From 325e4af356cc94232806588bf26d118a4fffe82d Mon Sep 17 00:00:00 2001
From: Sean Wei <me@sean.taipei>
Date: Thu, 7 Nov 2019 11:12:36 +0800
Subject: [PATCH 01/91] Fix building instruction of macOS (crashpad)

---
 docs/building-osx.md   | 4 ++--
 docs/building-xcode.md | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/docs/building-osx.md b/docs/building-osx.md
index fadd82002..8d51ed56b 100644
--- a/docs/building-osx.md
+++ b/docs/building-osx.md
@@ -213,12 +213,12 @@ Go to ***BuildPath*** and run
     git clone https://chromium.googlesource.com/crashpad/crashpad.git
     cd crashpad
     git checkout feb3aa3923
-    git apply ../../patches/crashpad.diff
+    git apply ../patches/crashpad.diff
     cd third_party/mini_chromium
     git clone https://chromium.googlesource.com/chromium/mini_chromium
     cd mini_chromium
     git checkout 7c5b0c1ab4
-    git apply ../../../../../patches/mini_chromium.diff
+    git apply ../../../../patches/mini_chromium.diff
     cd ../../gtest
     git clone https://chromium.googlesource.com/external/github.com/google/googletest gtest
     cd gtest
diff --git a/docs/building-xcode.md b/docs/building-xcode.md
index 220f823ab..a780a4ba0 100644
--- a/docs/building-xcode.md
+++ b/docs/building-xcode.md
@@ -213,12 +213,12 @@ Go to ***BuildPath*** and run
     git clone https://chromium.googlesource.com/crashpad/crashpad.git
     cd crashpad
     git checkout feb3aa3923
-    git apply ../../patches/crashpad.diff
+    git apply ../patches/crashpad.diff
     cd third_party/mini_chromium
     git clone https://chromium.googlesource.com/chromium/mini_chromium
     cd mini_chromium
     git checkout 7c5b0c1ab4
-    git apply ../../../../../patches/mini_chromium.diff
+    git apply ../../../../patches/mini_chromium.diff
     cd ../../gtest
     git clone https://chromium.googlesource.com/external/github.com/google/googletest gtest
     cd gtest

From a196b0aba723de85ee573594d9ad420412b6391a Mon Sep 17 00:00:00 2001
From: RadRussianRus <radrussianrus@gmail.com>
Date: Mon, 11 Nov 2019 19:39:48 +0300
Subject: [PATCH 02/91] Fixed animated stickers cache

---
 Telegram/SourceFiles/ffmpeg/ffmpeg_utility.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/ffmpeg/ffmpeg_utility.cpp b/Telegram/SourceFiles/ffmpeg/ffmpeg_utility.cpp
index 4693f2e11..6329bbddf 100644
--- a/Telegram/SourceFiles/ffmpeg/ffmpeg_utility.cpp
+++ b/Telegram/SourceFiles/ffmpeg/ffmpeg_utility.cpp
@@ -70,7 +70,7 @@ void PremultiplyLine(uchar *dst, const uchar *src, int intsCount) {
 
 #ifndef TDESKTOP_OFFICIAL_TARGET
 	for (auto i = 0; i != intsCount; ++i) {
-		dst[i] = qPremultiply(src[i]);
+		udst[i] = qPremultiply(usrc[i]);
 	}
 #elif QT_VERSION < QT_VERSION_CHECK(5, 12, 0)
 	static const auto layout = &qPixelLayouts[QImage::Format_ARGB32];

From 793862bee641e3b0eee59451897f50f1ab6e2ed2 Mon Sep 17 00:00:00 2001
From: Nicholas Guriev <guriev-ns@ya.ru>
Date: Tue, 12 Nov 2019 18:15:34 +0300
Subject: [PATCH 03/91] Fix -Wredundant-move and -Wdeprecated-copy warnings
 (#6663)

* Do not move result at end of function

This makes GCC 9.1.2 happy with the active -Wredundant-move warning.
Indeed, such moving of local variables or local arguments before
returning is unnecessary and prevents the compiler from copy elision
optimization.
---
 Telegram/SourceFiles/boxes/connection_box.cpp             | 2 +-
 Telegram/SourceFiles/boxes/create_poll_box.cpp            | 2 +-
 Telegram/SourceFiles/boxes/peers/edit_linked_chat_box.cpp | 2 +-
 .../SourceFiles/boxes/peers/edit_participants_box.cpp     | 4 ++--
 Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp   | 8 ++++----
 Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp   | 6 +++---
 Telegram/SourceFiles/calls/calls_box_controller.cpp       | 3 +--
 Telegram/SourceFiles/chat_helpers/emoji_list_widget.cpp   | 2 +-
 Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp    | 2 +-
 Telegram/SourceFiles/chat_helpers/stickers.cpp            | 2 +-
 .../SourceFiles/chat_helpers/stickers_list_widget.cpp     | 2 +-
 Telegram/SourceFiles/chat_helpers/tabbed_section.cpp      | 2 +-
 .../history/admin_log/history_admin_log_section.cpp       | 4 ++--
 .../SourceFiles/history/feed/history_feed_section.cpp     | 4 ++--
 .../history/view/history_view_scheduled_section.cpp       | 4 ++--
 .../SourceFiles/info/channels/info_channels_widget.cpp    | 4 ++--
 .../info/common_groups/info_common_groups_widget.cpp      | 4 ++--
 .../info/feed/info_feed_profile_inner_widget.cpp          | 2 +-
 .../SourceFiles/info/feed/info_feed_profile_widget.cpp    | 4 ++--
 Telegram/SourceFiles/info/info_memento.cpp                | 4 ++--
 Telegram/SourceFiles/info/info_wrap_widget.cpp            | 2 +-
 Telegram/SourceFiles/info/media/info_media_buttons.h      | 6 +++---
 Telegram/SourceFiles/info/media/info_media_widget.cpp     | 4 ++--
 Telegram/SourceFiles/info/members/info_members_widget.cpp | 4 ++--
 .../SourceFiles/info/profile/info_profile_actions.cpp     | 8 ++++----
 .../info/profile/info_profile_inner_widget.cpp            | 4 ++--
 Telegram/SourceFiles/info/profile/info_profile_widget.cpp | 4 ++--
 .../SourceFiles/info/settings/info_settings_widget.cpp    | 4 ++--
 .../SourceFiles/media/streaming/media_streaming_file.cpp  | 2 +-
 .../SourceFiles/passport/passport_panel_controller.cpp    | 4 ++--
 .../SourceFiles/settings/settings_privacy_controllers.cpp | 4 ++--
 .../SourceFiles/settings/settings_privacy_security.cpp    | 4 ++--
 Telegram/SourceFiles/window/window_outdated_bar.cpp       | 2 +-
 Telegram/lib_base                                         | 2 +-
 34 files changed, 60 insertions(+), 61 deletions(-)

diff --git a/Telegram/SourceFiles/boxes/connection_box.cpp b/Telegram/SourceFiles/boxes/connection_box.cpp
index a4873f019..663739f26 100644
--- a/Telegram/SourceFiles/boxes/connection_box.cpp
+++ b/Telegram/SourceFiles/boxes/connection_box.cpp
@@ -1148,7 +1148,7 @@ object_ptr<Ui::BoxContent> ProxiesBoxController::create() {
 	for (const auto &item : _list) {
 		updateView(item);
 	}
-	return std::move(result);
+	return result;
 }
 
 auto ProxiesBoxController::findById(int id) -> std::vector<Item>::iterator {
diff --git a/Telegram/SourceFiles/boxes/create_poll_box.cpp b/Telegram/SourceFiles/boxes/create_poll_box.cpp
index ad9a1db47..11d44d311 100644
--- a/Telegram/SourceFiles/boxes/create_poll_box.cpp
+++ b/Telegram/SourceFiles/boxes/create_poll_box.cpp
@@ -768,7 +768,7 @@ object_ptr<Ui::RpWidget> CreatePollBox::setupContent() {
 		FocusAtEnd(question);
 	}, lifetime());
 
-	return std::move(result);
+	return result;
 }
 
 void CreatePollBox::prepare() {
diff --git a/Telegram/SourceFiles/boxes/peers/edit_linked_chat_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_linked_chat_box.cpp
index d490a38f4..cc55265a8 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_linked_chat_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_linked_chat_box.cpp
@@ -223,7 +223,7 @@ object_ptr<Ui::RpWidget> SetupAbout(
 			tr::now,
 			Ui::Text::WithEntities);
 	}());
-	return std::move(about);
+	return about;
 }
 
 object_ptr<Ui::RpWidget> SetupFooter(
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
index 09a0960f6..892b5a6a6 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
@@ -1786,7 +1786,7 @@ std::unique_ptr<PeerListRow> ParticipantsBoxController::createRow(
 			row->setActionLink(tr::lng_profile_kick(tr::now));
 		}
 	}
-	return std::move(row);
+	return row;
 }
 
 auto ParticipantsBoxController::computeType(
@@ -1931,7 +1931,7 @@ auto ParticipantsBoxSearchController::saveState() const
 	result->offset = _offset;
 	result->allLoaded = _allLoaded;
 	result->wasLoading = (_requestId != 0);
-	return std::move(result);
+	return result;
 }
 
 void ParticipantsBoxSearchController::restoreState(
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
index 918901b88..c84e6be4e 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
@@ -478,7 +478,7 @@ object_ptr<Ui::RpWidget> Controller::createTitleEdit() {
 		[=] { submitTitle(); });
 
 	_controls.title = result->entity();
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::RpWidget> Controller::createDescriptionEdit() {
@@ -512,7 +512,7 @@ object_ptr<Ui::RpWidget> Controller::createDescriptionEdit() {
 		[=] { submitDescription(); });
 
 	_controls.description = result->entity();
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::RpWidget> Controller::createManageGroupButtons() {
@@ -526,7 +526,7 @@ object_ptr<Ui::RpWidget> Controller::createManageGroupButtons() {
 
 	fillManageSection();
 
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::RpWidget> Controller::createStickersEdit() {
@@ -564,7 +564,7 @@ object_ptr<Ui::RpWidget> Controller::createStickersEdit() {
 		Ui::show(Box<StickersBox>(channel), Ui::LayerOption::KeepOther);
 	});
 
-	return std::move(result);
+	return result;
 }
 
 bool Controller::canEditInformation() const {
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
index 7c67aba61..8dd0c2eaa 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
@@ -364,7 +364,7 @@ object_ptr<Ui::RpWidget> Controller::createUsernameEdit() {
 	const auto shown = (_controls.privacy->value() == Privacy::HasUsername);
 	result->toggle(shown, anim::type::instant);
 
-	return std::move(result);
+	return result;
 }
 
 void Controller::privacyChanged(Privacy value) {
@@ -630,7 +630,7 @@ object_ptr<Ui::RpWidget> Controller::createInviteLinkEdit() {
 
 	observeInviteLink();
 
-	return std::move(result);
+	return result;
 }
 
 void Controller::refreshEditInviteLink() {
@@ -692,7 +692,7 @@ object_ptr<Ui::RpWidget> Controller::createInviteLinkCreate() {
 
 	observeInviteLink();
 
-	return std::move(result);
+	return result;
 }
 
 void Controller::refreshCreateInviteLink() {
diff --git a/Telegram/SourceFiles/calls/calls_box_controller.cpp b/Telegram/SourceFiles/calls/calls_box_controller.cpp
index 937c34a74..ab5189452 100644
--- a/Telegram/SourceFiles/calls/calls_box_controller.cpp
+++ b/Telegram/SourceFiles/calls/calls_box_controller.cpp
@@ -404,8 +404,7 @@ BoxController::Row *BoxController::rowForItem(not_null<const HistoryItem*> item)
 
 std::unique_ptr<PeerListRow> BoxController::createRow(
 		not_null<HistoryItem*> item) const {
-	auto row = std::make_unique<Row>(item);
-	return std::move(row);
+	return std::make_unique<Row>(item);
 }
 
 } // namespace Calls
diff --git a/Telegram/SourceFiles/chat_helpers/emoji_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/emoji_list_widget.cpp
index a9b4129f0..3f597b931 100644
--- a/Telegram/SourceFiles/chat_helpers/emoji_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/emoji_list_widget.cpp
@@ -427,7 +427,7 @@ object_ptr<TabbedSelector::InnerFooter> EmojiListWidget::createFooter() {
 	Expects(_footer == nullptr);
 	auto result = object_ptr<Footer>(this);
 	_footer = result;
-	return std::move(result);
+	return result;
 }
 
 template <typename Callback>
diff --git a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
index cd1dc1d38..274f12f61 100644
--- a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
@@ -178,7 +178,7 @@ object_ptr<TabbedSelector::InnerFooter> GifsListWidget::createFooter() {
 
 	auto result = object_ptr<Footer>(this);
 	_footer = result;
-	return std::move(result);
+	return result;
 }
 
 void GifsListWidget::visibleTopBottomUpdated(
diff --git a/Telegram/SourceFiles/chat_helpers/stickers.cpp b/Telegram/SourceFiles/chat_helpers/stickers.cpp
index 6cebd226f..9b25b7fa0 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers.cpp
+++ b/Telegram/SourceFiles/chat_helpers/stickers.cpp
@@ -891,7 +891,7 @@ std::optional<std::vector<not_null<EmojiPtr>>> GetEmojiListFromSet(
 		if (result.empty()) {
 			return std::nullopt;
 		}
-		return std::move(result);
+		return result;
 	}
 	return std::nullopt;
 }
diff --git a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
index e3cb75407..d53b516a0 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
@@ -878,7 +878,7 @@ object_ptr<TabbedSelector::InnerFooter> StickersListWidget::createFooter() {
 
 	auto result = object_ptr<Footer>(this);
 	_footer = result;
-	return std::move(result);
+	return result;
 }
 
 void StickersListWidget::visibleTopBottomUpdated(
diff --git a/Telegram/SourceFiles/chat_helpers/tabbed_section.cpp b/Telegram/SourceFiles/chat_helpers/tabbed_section.cpp
index 990ccbd78..57a6d9325 100644
--- a/Telegram/SourceFiles/chat_helpers/tabbed_section.cpp
+++ b/Telegram/SourceFiles/chat_helpers/tabbed_section.cpp
@@ -20,7 +20,7 @@ object_ptr<Window::SectionWidget> TabbedMemento::createWidget(
 		const QRect &geometry) {
 	auto result = object_ptr<TabbedSection>(parent, controller);
 	result->setGeometry(geometry);
-	return std::move(result);
+	return result;
 }
 
 TabbedSection::TabbedSection(
diff --git a/Telegram/SourceFiles/history/admin_log/history_admin_log_section.cpp b/Telegram/SourceFiles/history/admin_log/history_admin_log_section.cpp
index 2e5ad7f76..d73bbea33 100644
--- a/Telegram/SourceFiles/history/admin_log/history_admin_log_section.cpp
+++ b/Telegram/SourceFiles/history/admin_log/history_admin_log_section.cpp
@@ -97,7 +97,7 @@ object_ptr<Window::SectionWidget> SectionMemento::createWidget(
 	}
 	auto result = object_ptr<Widget>(parent, controller, _channel);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 FixedBar::FixedBar(
@@ -365,7 +365,7 @@ void Widget::setupShortcuts() {
 std::unique_ptr<Window::SectionMemento> Widget::createMemento() {
 	auto result = std::make_unique<SectionMemento>(channel());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<SectionMemento*> memento) {
diff --git a/Telegram/SourceFiles/history/feed/history_feed_section.cpp b/Telegram/SourceFiles/history/feed/history_feed_section.cpp
index ceb360c09..571492247 100644
--- a/Telegram/SourceFiles/history/feed/history_feed_section.cpp
+++ b/Telegram/SourceFiles/history/feed/history_feed_section.cpp
@@ -59,7 +59,7 @@ object_ptr<Window::SectionWidget> Memento::createWidget(
 	}
 	auto result = object_ptr<Widget>(parent, controller, _feed);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 Widget::Widget(
@@ -456,7 +456,7 @@ ClickHandlerPtr Widget::listDateLink(not_null<Element*> view) {
 std::unique_ptr<Window::SectionMemento> Widget::createMemento() {
 	auto result = std::make_unique<Memento>(_feed);
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/history/view/history_view_scheduled_section.cpp b/Telegram/SourceFiles/history/view/history_view_scheduled_section.cpp
index 93e61fa71..0730b1869 100644
--- a/Telegram/SourceFiles/history/view/history_view_scheduled_section.cpp
+++ b/Telegram/SourceFiles/history/view/history_view_scheduled_section.cpp
@@ -67,7 +67,7 @@ object_ptr<Window::SectionWidget> ScheduledMemento::createWidget(
 	}
 	auto result = object_ptr<ScheduledWidget>(parent, controller, _history);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 ScheduledWidget::ScheduledWidget(
@@ -714,7 +714,7 @@ bool ScheduledWidget::returnTabbedSelector() {
 std::unique_ptr<Window::SectionMemento> ScheduledWidget::createMemento() {
 	auto result = std::make_unique<ScheduledMemento>(history());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void ScheduledWidget::saveState(not_null<ScheduledMemento*> memento) {
diff --git a/Telegram/SourceFiles/info/channels/info_channels_widget.cpp b/Telegram/SourceFiles/info/channels/info_channels_widget.cpp
index d6bbd1671..3b6c115a1 100644
--- a/Telegram/SourceFiles/info/channels/info_channels_widget.cpp
+++ b/Telegram/SourceFiles/info/channels/info_channels_widget.cpp
@@ -35,7 +35,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		parent,
 		controller);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 void Memento::setState(std::unique_ptr<SavedState> state) {
@@ -79,7 +79,7 @@ void Widget::setInternalState(
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(controller());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/info/common_groups/info_common_groups_widget.cpp b/Telegram/SourceFiles/info/common_groups/info_common_groups_widget.cpp
index c74a78f1b..524e4e977 100644
--- a/Telegram/SourceFiles/info/common_groups/info_common_groups_widget.cpp
+++ b/Telegram/SourceFiles/info/common_groups/info_common_groups_widget.cpp
@@ -33,7 +33,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		controller,
 		Auth().data().user(userId()));
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 void Memento::setListState(std::unique_ptr<PeerListState> state) {
@@ -85,7 +85,7 @@ void Widget::setInternalState(
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(user()->bareId());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/info/feed/info_feed_profile_inner_widget.cpp b/Telegram/SourceFiles/info/feed/info_feed_profile_inner_widget.cpp
index 2fee32e9b..b5f8d48c5 100644
--- a/Telegram/SourceFiles/info/feed/info_feed_profile_inner_widget.cpp
+++ b/Telegram/SourceFiles/info/feed/info_feed_profile_inner_widget.cpp
@@ -61,7 +61,7 @@ object_ptr<Ui::RpWidget> InnerWidget::setupContent(
 		_scrollToRequests.fire({ min, max });
 	}, _channels->lifetime());
 
-	return std::move(result);
+	return result;
 }
 
 int InnerWidget::countDesiredHeight() const {
diff --git a/Telegram/SourceFiles/info/feed/info_feed_profile_widget.cpp b/Telegram/SourceFiles/info/feed/info_feed_profile_widget.cpp
index bf77083ea..ec09c252c 100644
--- a/Telegram/SourceFiles/info/feed/info_feed_profile_widget.cpp
+++ b/Telegram/SourceFiles/info/feed/info_feed_profile_widget.cpp
@@ -35,7 +35,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		parent,
 		controller);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 void Memento::setChannelsState(std::unique_ptr<ChannelsState> state) {
@@ -99,7 +99,7 @@ void Widget::setInternalState(
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(controller());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/info/info_memento.cpp b/Telegram/SourceFiles/info/info_memento.cpp
index a4495b677..f7d75ef63 100644
--- a/Telegram/SourceFiles/info/info_memento.cpp
+++ b/Telegram/SourceFiles/info/info_memento.cpp
@@ -160,7 +160,7 @@ object_ptr<Window::SectionWidget> Memento::createWidget(
 		wrap,
 		this);
 	result->setGeometry(geometry);
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::LayerWidget> Memento::createLayer(
@@ -198,7 +198,7 @@ object_ptr<Window::SectionWidget> MoveMemento::createWidget(
 		wrap,
 		this);
 	result->setGeometry(geometry);
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::LayerWidget> MoveMemento::createLayer(
diff --git a/Telegram/SourceFiles/info/info_wrap_widget.cpp b/Telegram/SourceFiles/info/info_wrap_widget.cpp
index 4ef14a780..88440a5de 100644
--- a/Telegram/SourceFiles/info/info_wrap_widget.cpp
+++ b/Telegram/SourceFiles/info/info_wrap_widget.cpp
@@ -1043,7 +1043,7 @@ object_ptr<Ui::RpWidget> WrapWidget::createTopBarSurrogate(
 		});
 		result->setGeometry(_topBar->geometry());
 		result->show();
-		return std::move(result);
+		return result;
 	}
 	return nullptr;
 }
diff --git a/Telegram/SourceFiles/info/media/info_media_buttons.h b/Telegram/SourceFiles/info/media/info_media_buttons.h
index e79cac60d..56427c835 100644
--- a/Telegram/SourceFiles/info/media/info_media_buttons.h
+++ b/Telegram/SourceFiles/info/media/info_media_buttons.h
@@ -94,7 +94,7 @@ inline auto AddButton(
 		navigation->showSection(
 			Info::Memento(peer->id, Section(type)));
 	});
-	return std::move(result);
+	return result;
 };
 
 inline auto AddCommonGroupsButton(
@@ -113,8 +113,8 @@ inline auto AddCommonGroupsButton(
 		navigation->showSection(
 			Info::Memento(user->id, Section::Type::CommonGroups));
 	});
-	return std::move(result);
+	return result;
 };
 
 } // namespace Media
-} // namespace Info
\ No newline at end of file
+} // namespace Info
diff --git a/Telegram/SourceFiles/info/media/info_media_widget.cpp b/Telegram/SourceFiles/info/media/info_media_widget.cpp
index ab405f56e..dece63f6f 100644
--- a/Telegram/SourceFiles/info/media/info_media_widget.cpp
+++ b/Telegram/SourceFiles/info/media/info_media_widget.cpp
@@ -65,7 +65,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		parent,
 		controller);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 Widget::Widget(
@@ -117,7 +117,7 @@ void Widget::setInternalState(
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(controller());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/info/members/info_members_widget.cpp b/Telegram/SourceFiles/info/members/info_members_widget.cpp
index 5e8f4e0c6..d0e9c35b0 100644
--- a/Telegram/SourceFiles/info/members/info_members_widget.cpp
+++ b/Telegram/SourceFiles/info/members/info_members_widget.cpp
@@ -38,7 +38,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		parent,
 		controller);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 void Memento::setState(std::unique_ptr<SavedState> state) {
@@ -82,7 +82,7 @@ void Widget::setInternalState(
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(controller());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/info/profile/info_profile_actions.cpp b/Telegram/SourceFiles/info/profile/info_profile_actions.cpp
index 0b08107ba..2526057a2 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_actions.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_actions.cpp
@@ -344,7 +344,7 @@ object_ptr<Ui::RpWidget> DetailsFiller::setupInfo() {
 		result,
 		st::infoIconInformation,
 		st::infoInformationIconPosition);
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::RpWidget> DetailsFiller::setupMuteToggle() {
@@ -365,7 +365,7 @@ object_ptr<Ui::RpWidget> DetailsFiller::setupMuteToggle() {
 		result,
 		st::infoIconNotifications,
 		st::infoNotificationsIconPosition);
-	return std::move(result);
+	return result;
 }
 
 void DetailsFiller::setupMainButtons() {
@@ -775,7 +775,7 @@ object_ptr<Ui::RpWidget> ActionsFiller::fill() {
 //		result,
 //		st::infoIconNotifications,
 //		st::infoNotificationsIconPosition);
-//	return std::move(result);
+//	return result;
 //}
 
 } // namespace
@@ -870,7 +870,7 @@ object_ptr<Ui::RpWidget> SetupChannelMembers(
 		st::infoChannelMembersIconPosition);
 	members->add(CreateSkipWidget(members));
 
-	return std::move(result);
+	return result;
 }
 // // #feed
 //object_ptr<Ui::RpWidget> SetupFeedDetails(
diff --git a/Telegram/SourceFiles/info/profile/info_profile_inner_widget.cpp b/Telegram/SourceFiles/info/profile/info_profile_inner_widget.cpp
index ce67c438a..e1eaa4b21 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_inner_widget.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_inner_widget.cpp
@@ -125,7 +125,7 @@ object_ptr<Ui::RpWidget> InnerWidget::setupContent(
 		}, _members->lifetime());
 		_cover->setOnlineCount(_members->onlineCountValue());
 	}
-	return std::move(result);
+	return result;
 }
 
 object_ptr<Ui::RpWidget> InnerWidget::setupSharedMedia(
@@ -227,7 +227,7 @@ object_ptr<Ui::RpWidget> InnerWidget::setupSharedMedia(
 	)->setAttribute(Qt::WA_TransparentForMouseEvents);
 
 	_sharedMediaWrap = result;
-	return std::move(result);
+	return result;
 }
 
 int InnerWidget::countDesiredHeight() const {
diff --git a/Telegram/SourceFiles/info/profile/info_profile_widget.cpp b/Telegram/SourceFiles/info/profile/info_profile_widget.cpp
index f2d7546ea..f8156e14c 100644
--- a/Telegram/SourceFiles/info/profile/info_profile_widget.cpp
+++ b/Telegram/SourceFiles/info/profile/info_profile_widget.cpp
@@ -38,7 +38,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		parent,
 		controller);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 void Memento::setMembersState(std::unique_ptr<MembersState> state) {
@@ -102,7 +102,7 @@ void Widget::setInternalState(
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(controller());
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/info/settings/info_settings_widget.cpp b/Telegram/SourceFiles/info/settings/info_settings_widget.cpp
index 5b7b8818a..689164a8b 100644
--- a/Telegram/SourceFiles/info/settings/info_settings_widget.cpp
+++ b/Telegram/SourceFiles/info/settings/info_settings_widget.cpp
@@ -32,7 +32,7 @@ object_ptr<ContentWidget> Memento::createWidget(
 		parent,
 		controller);
 	result->setInternalState(geometry, this);
-	return std::move(result);
+	return result;
 }
 
 Memento::~Memento() = default;
@@ -95,7 +95,7 @@ rpl::producer<bool> Widget::desiredShadowVisibility() const {
 std::unique_ptr<ContentMemento> Widget::doCreateMemento() {
 	auto result = std::make_unique<Memento>(self(), _type);
 	saveState(result.get());
-	return std::move(result);
+	return result;
 }
 
 void Widget::saveState(not_null<Memento*> memento) {
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_file.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_file.cpp
index 2b66026b1..3762a4180 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_file.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_file.cpp
@@ -215,7 +215,7 @@ base::variant<FFmpeg::Packet, FFmpeg::AvErrorWrap> File::Context::readPacket() {
 	if (unroll()) {
 		return FFmpeg::AvErrorWrap();
 	} else if (!error) {
-		return std::move(result);
+		return result;
 	} else if (error.code() != AVERROR_EOF) {
 		logFatal(qstr("av_read_frame"), error);
 	}
diff --git a/Telegram/SourceFiles/passport/passport_panel_controller.cpp b/Telegram/SourceFiles/passport/passport_panel_controller.cpp
index c67cd04bb..4e0cf1568 100644
--- a/Telegram/SourceFiles/passport/passport_panel_controller.cpp
+++ b/Telegram/SourceFiles/passport/passport_panel_controller.cpp
@@ -1192,7 +1192,7 @@ void PanelController::startScopeEdit(
 			_panelHasUnsavedChanges = [=] {
 				return weak ? weak->hasUnsavedChanges() : false;
 			};
-			return std::move(result);
+			return result;
 		} break;
 		case Scope::Type::PersonalDetails:
 		case Scope::Type::AddressDetails: {
@@ -1210,7 +1210,7 @@ void PanelController::startScopeEdit(
 			_panelHasUnsavedChanges = [=] {
 				return weak ? weak->hasUnsavedChanges() : false;
 			};
-			return std::move(result);
+			return result;
 		} break;
 		case Scope::Type::Phone:
 		case Scope::Type::Email: {
diff --git a/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp b/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
index 1aaae0be2..6a15f9733 100644
--- a/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
+++ b/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
@@ -334,7 +334,7 @@ std::unique_ptr<PeerListRow> BlockedBoxController::createRow(
 		return tr::lng_blocked_list_unknown_phone(tr::now);
 	}();
 	row->setCustomStatus(status);
-	return std::move(row);
+	return row;
 }
 
 ApiWrap::Privacy::Key PhoneNumberPrivacyController::key() {
@@ -444,7 +444,7 @@ object_ptr<Ui::RpWidget> PhoneNumberPrivacyController::setupMiddleWidget(
 			QVector<MTPInputPrivacyRule>(1, value));
 	};
 
-	return std::move(widget);
+	return widget;
 }
 
 void PhoneNumberPrivacyController::saveAdditional() {
diff --git a/Telegram/SourceFiles/settings/settings_privacy_security.cpp b/Telegram/SourceFiles/settings/settings_privacy_security.cpp
index 3557a23ef..b2f6f99f4 100644
--- a/Telegram/SourceFiles/settings/settings_privacy_security.cpp
+++ b/Telegram/SourceFiles/settings/settings_privacy_security.cpp
@@ -525,7 +525,7 @@ object_ptr<Ui::BoxContent> EditCloudPasswordBox(not_null<Main::Session*> session
 		session->api().clearUnconfirmedPassword();
 	}, box->lifetime());
 
-	return std::move(result);
+	return result;
 }
 
 void RemoveCloudPassword(not_null<::Main::Session*> session) {
@@ -565,7 +565,7 @@ object_ptr<Ui::BoxContent> CloudPasswordAppOutdatedBox() {
 		tr::lng_menu_update(tr::now),
 		callback);
 	*box = result.data();
-	return std::move(result);
+	return result;
 }
 
 void AddPrivacyButton(
diff --git a/Telegram/SourceFiles/window/window_outdated_bar.cpp b/Telegram/SourceFiles/window/window_outdated_bar.cpp
index b585edf02..545b499d5 100644
--- a/Telegram/SourceFiles/window/window_outdated_bar.cpp
+++ b/Telegram/SourceFiles/window/window_outdated_bar.cpp
@@ -162,7 +162,7 @@ object_ptr<Ui::RpWidget> CreateOutdatedBar(not_null<QWidget*> parent) {
 		Closed();
 	}, wrap->lifetime());
 
-	return std::move(result);
+	return result;
 }
 
 } // namespace Window
diff --git a/Telegram/lib_base b/Telegram/lib_base
index a94ad7f81..3aaab8850 160000
--- a/Telegram/lib_base
+++ b/Telegram/lib_base
@@ -1 +1 @@
-Subproject commit a94ad7f817c1e1aeb242843d90f2bac313daab7a
+Subproject commit 3aaab885075b503950327e544316cd71a1412651

From 3b1fd9e45a17e89a855fbd9692f2ef62b0824498 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 12 Nov 2019 15:26:14 +0300
Subject: [PATCH 04/91] Fix travis build.

---
 .travis.yml      | 1 +
 .travis/build.sh | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 983351096..46708f159 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -49,6 +49,7 @@ addons:
       - libvdpau-dev
       - libxcb-xkb-dev
       - libxkbcommon-dev
+      - libatspi2.0-dev
       - lintian
       - quilt
       - valac
diff --git a/.travis/build.sh b/.travis/build.sh
index 91d9e06b1..1a1f55d78 100755
--- a/.travis/build.sh
+++ b/.travis/build.sh
@@ -17,7 +17,7 @@ XKB_PATH="$BUILD/libxkbcommon"
 XKB_CACHE_VERSION="3"
 
 QT_PATH="$BUILD/qt"
-QT_CACHE_VERSION="4"
+QT_CACHE_VERSION="5"
 QT_PATCH="$EXTERNAL/patches/qtbase_${QT_VERSION//\./_}.diff"
 
 BREAKPAD_PATH="$BUILD/breakpad"

From 0c0c8f3584b500ef053bb1a4d9165cdbd9e18394 Mon Sep 17 00:00:00 2001
From: Christian Hesse <mail@eworm.de>
Date: Tue, 12 Nov 2019 23:36:00 +0100
Subject: [PATCH 05/91] libnotify: capabilities are not exclusive

Capabilities "actions" and "body-markup" can be available at the
same time.

Signed-off-by: Christian Hesse <mail@eworm.de>
---
 .../SourceFiles/platform/linux/notifications_manager_linux.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp b/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp
index 0248e9152..cfba893de 100644
--- a/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp
+++ b/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp
@@ -371,7 +371,8 @@ void Manager::Private::init(Manager *manager) {
 		LOG(("LibNotify capabilities: %1").arg(_capabilities.join(qstr(", "))));
 		if (_capabilities.contains(qsl("actions"))) {
 			_actionsSupported = true;
-		} else if (_capabilities.contains(qsl("body-markup"))) {
+		}
+		if (_capabilities.contains(qsl("body-markup"))) {
 			_markupSupported = true;
 		}
 	} else {

From 2577bedeac3e236230d1bfabf30f124b74ba4034 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 13 Nov 2019 11:31:12 +0300
Subject: [PATCH 06/91] Remove mtproto/facade.h from main pch.

---
 Telegram/SourceFiles/boxes/calendar_box.cpp   |  1 +
 Telegram/SourceFiles/boxes/confirm_box.h      |  1 +
 .../SourceFiles/boxes/confirm_phone_box.cpp   |  1 +
 .../SourceFiles/boxes/confirm_phone_box.h     |  1 +
 Telegram/SourceFiles/boxes/edit_caption_box.h |  1 +
 .../boxes/peers/edit_participant_box.h        |  2 +
 Telegram/SourceFiles/boxes/report_box.cpp     |  1 +
 Telegram/SourceFiles/boxes/report_box.h       |  1 +
 Telegram/SourceFiles/boxes/share_box.h        |  1 +
 Telegram/SourceFiles/boxes/username_box.h     |  1 +
 .../dialogs/dialogs_inner_widget.h            |  1 +
 Telegram/SourceFiles/dialogs/dialogs_widget.h |  1 +
 Telegram/SourceFiles/main/main_account.h      |  1 +
 Telegram/SourceFiles/main/main_session.h      |  4 ++
 Telegram/SourceFiles/mainwidget.h             |  1 +
 Telegram/SourceFiles/mtproto/auth_key.cpp     | 58 ++++++++++++++++++
 Telegram/SourceFiles/mtproto/auth_key.h       | 60 ++++---------------
 .../SourceFiles/mtproto/concurrent_sender.cpp |  1 +
 .../SourceFiles/mtproto/config_loader.cpp     |  1 +
 Telegram/SourceFiles/mtproto/connection.cpp   | 16 ++---
 Telegram/SourceFiles/mtproto/connection.h     |  1 +
 .../SourceFiles/mtproto/connection_abstract.h |  3 +
 .../mtproto/connection_resolving.cpp          |  2 +
 Telegram/SourceFiles/mtproto/dc_options.cpp   |  1 +
 .../mtproto/dedicated_file_loader.cpp         |  1 +
 .../mtproto/dedicated_file_loader.h           |  4 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 25 ++++----
 Telegram/SourceFiles/mtproto/mtp_instance.h   |  5 +-
 Telegram/SourceFiles/mtproto/sender.h         |  3 +
 Telegram/SourceFiles/stdafx.h                 |  3 +-
 Telegram/SourceFiles/storage/file_download.h  |  1 +
 Telegram/SourceFiles/storage/file_upload.h    |  1 +
 .../window/window_connecting_widget.cpp       |  1 +
 33 files changed, 133 insertions(+), 73 deletions(-)

diff --git a/Telegram/SourceFiles/boxes/calendar_box.cpp b/Telegram/SourceFiles/boxes/calendar_box.cpp
index 25bbbfe79..54b14b221 100644
--- a/Telegram/SourceFiles/boxes/calendar_box.cpp
+++ b/Telegram/SourceFiles/boxes/calendar_box.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "boxes/calendar_box.h"
 
+#include "mtproto/rpc_sender.h"
 #include "ui/widgets/buttons.h"
 #include "lang/lang_keys.h"
 #include "ui/effects/ripple_animation.h"
diff --git a/Telegram/SourceFiles/boxes/confirm_box.h b/Telegram/SourceFiles/boxes/confirm_box.h
index 07c4971c0..cda3e0670 100644
--- a/Telegram/SourceFiles/boxes/confirm_box.h
+++ b/Telegram/SourceFiles/boxes/confirm_box.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "boxes/abstract_box.h"
+#include "mtproto/rpc_sender.h"
 
 namespace Main {
 class Session;
diff --git a/Telegram/SourceFiles/boxes/confirm_phone_box.cpp b/Telegram/SourceFiles/boxes/confirm_phone_box.cpp
index 8e4b8bf48..6cd1a62e2 100644
--- a/Telegram/SourceFiles/boxes/confirm_phone_box.cpp
+++ b/Telegram/SourceFiles/boxes/confirm_phone_box.cpp
@@ -19,6 +19,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "numbers.h"
 #include "app.h"
 #include "lang/lang_keys.h"
+#include "mtproto/facade.h"
 #include "styles/style_layers.h"
 #include "styles/style_boxes.h"
 
diff --git a/Telegram/SourceFiles/boxes/confirm_phone_box.h b/Telegram/SourceFiles/boxes/confirm_phone_box.h
index d2963f960..b474df152 100644
--- a/Telegram/SourceFiles/boxes/confirm_phone_box.h
+++ b/Telegram/SourceFiles/boxes/confirm_phone_box.h
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/abstract_box.h"
 #include "base/timer.h"
 #include "ui/widgets/input_fields.h"
+#include "mtproto/rpc_sender.h"
 
 namespace Ui {
 class InputField;
diff --git a/Telegram/SourceFiles/boxes/edit_caption_box.h b/Telegram/SourceFiles/boxes/edit_caption_box.h
index 14e7cd5c3..59e821954 100644
--- a/Telegram/SourceFiles/boxes/edit_caption_box.h
+++ b/Telegram/SourceFiles/boxes/edit_caption_box.h
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/storage_media_prepare.h"
 #include "ui/wrap/slide_wrap.h"
 #include "media/clip/media_clip_reader.h"
+#include "mtproto/rpc_sender.h"
 
 namespace ChatHelpers {
 class TabbedPanel;
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participant_box.h b/Telegram/SourceFiles/boxes/peers/edit_participant_box.h
index 7ef9e877e..689b08a7b 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participant_box.h
+++ b/Telegram/SourceFiles/boxes/peers/edit_participant_box.h
@@ -10,6 +10,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/abstract_box.h"
 #include "base/unique_qptr.h"
 
+class RPCError;
+
 namespace Ui {
 class FlatLabel;
 class LinkButton;
diff --git a/Telegram/SourceFiles/boxes/report_box.cpp b/Telegram/SourceFiles/boxes/report_box.cpp
index 5ad271db2..28697df52 100644
--- a/Telegram/SourceFiles/boxes/report_box.cpp
+++ b/Telegram/SourceFiles/boxes/report_box.cpp
@@ -14,6 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/input_fields.h"
 #include "ui/toast/toast.h"
+#include "mtproto/facade.h"
 #include "mainwindow.h"
 #include "styles/style_layers.h"
 #include "styles/style_boxes.h"
diff --git a/Telegram/SourceFiles/boxes/report_box.h b/Telegram/SourceFiles/boxes/report_box.h
index d7afc3761..17ed36236 100644
--- a/Telegram/SourceFiles/boxes/report_box.h
+++ b/Telegram/SourceFiles/boxes/report_box.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "boxes/abstract_box.h"
+#include "mtproto/rpc_sender.h"
 
 namespace Ui {
 template <typename Enum>
diff --git a/Telegram/SourceFiles/boxes/share_box.h b/Telegram/SourceFiles/boxes/share_box.h
index 55d223c04..822c7477f 100644
--- a/Telegram/SourceFiles/boxes/share_box.h
+++ b/Telegram/SourceFiles/boxes/share_box.h
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "ui/effects/animations.h"
 #include "ui/effects/round_checkbox.h"
+#include "mtproto/rpc_sender.h"
 
 enum class SendMenuType;
 
diff --git a/Telegram/SourceFiles/boxes/username_box.h b/Telegram/SourceFiles/boxes/username_box.h
index 2cc31dd52..433d9c05c 100644
--- a/Telegram/SourceFiles/boxes/username_box.h
+++ b/Telegram/SourceFiles/boxes/username_box.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "boxes/abstract_box.h"
+#include "mtproto/rpc_sender.h"
 
 namespace Ui {
 class UsernameInput;
diff --git a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
index b5b29a017..d0b8d5d7e 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/rp_widget.h"
 #include "base/flags.h"
 #include "base/object_ptr.h"
+#include "mtproto/rpc_sender.h"
 
 namespace Main {
 class Session;
diff --git a/Telegram/SourceFiles/dialogs/dialogs_widget.h b/Telegram/SourceFiles/dialogs/dialogs_widget.h
index 9fd8509e6..8d99ef5cc 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_widget.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_widget.h
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/scroll_area.h"
 #include "ui/special_buttons.h"
 #include "api/api_single_message_search.h"
+#include "mtproto/rpc_sender.h"
 
 namespace Main {
 class Session;
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 44765995a..6729c086e 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/auth_key.h"
+#include "mtproto/mtp_instance.h"
 #include "base/weak_ptr.h"
 
 namespace Main {
diff --git a/Telegram/SourceFiles/main/main_session.h b/Telegram/SourceFiles/main/main_session.h
index 91cf0c45b..34231c0a2 100644
--- a/Telegram/SourceFiles/main/main_session.h
+++ b/Telegram/SourceFiles/main/main_session.h
@@ -15,6 +15,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 class ApiWrap;
 
+namespace MTP {
+class Instance;
+} // namespace MTP
+
 namespace Support {
 class Helper;
 class Templates;
diff --git a/Telegram/SourceFiles/mainwidget.h b/Telegram/SourceFiles/mainwidget.h
index f2bd4ce59..cdce6b299 100644
--- a/Telegram/SourceFiles/mainwidget.h
+++ b/Telegram/SourceFiles/mainwidget.h
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/effects/animations.h"
 #include "media/player/media_player_float.h"
 #include "data/data_pts_waiter.h"
+#include "mtproto/rpc_sender.h"
 
 struct HistoryMessageMarkupButton;
 class MainWindow;
diff --git a/Telegram/SourceFiles/mtproto/auth_key.cpp b/Telegram/SourceFiles/mtproto/auth_key.cpp
index b9ef48800..f116a707b 100644
--- a/Telegram/SourceFiles/mtproto/auth_key.cpp
+++ b/Telegram/SourceFiles/mtproto/auth_key.cpp
@@ -14,6 +14,29 @@ extern "C" {
 
 namespace MTP {
 
+AuthKey::AuthKey(Type type, DcId dcId, const Data &data)
+: _type(type)
+, _dcId(dcId)
+, _key(data) {
+	countKeyId();
+}
+
+AuthKey::AuthKey(const Data &data) : _type(Type::Local), _key(data) {
+	countKeyId();
+}
+
+AuthKey::Type AuthKey::type() const {
+	return _type;
+}
+
+int AuthKey::dcId() const {
+	return _dcId;
+}
+
+AuthKey::KeyId AuthKey::keyId() const {
+	return _keyId;
+}
+
 void AuthKey::prepareAES_oldmtp(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const {
 	uint32 x = send ? 0 : 8;
 
@@ -72,6 +95,41 @@ void AuthKey::prepareAES(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &
 	memcpy(iv + 8 + 16, sha256_b + 24, 8);
 }
 
+const void *AuthKey::partForMsgKey(bool send) const {
+	return _key.data() + 88 + (send ? 0 : 8);
+}
+
+void AuthKey::write(QDataStream &to) const {
+	to.writeRawData(reinterpret_cast<const char*>(_key.data()), _key.size());
+}
+
+bytes::const_span AuthKey::data() const {
+	return _key;
+}
+
+bool AuthKey::equals(const std::shared_ptr<AuthKey> &other) const {
+	return other ? (_key == other->_key) : false;
+}
+
+void AuthKey::FillData(Data &authKey, bytes::const_span computedAuthKey) {
+	auto computedAuthKeySize = computedAuthKey.size();
+	Assert(computedAuthKeySize <= kSize);
+	auto authKeyBytes = gsl::make_span(authKey);
+	if (computedAuthKeySize < kSize) {
+		bytes::set_with_const(authKeyBytes.subspan(0, kSize - computedAuthKeySize), gsl::byte());
+		bytes::copy(authKeyBytes.subspan(kSize - computedAuthKeySize), computedAuthKey);
+	} else {
+		bytes::copy(authKeyBytes, computedAuthKey);
+	}
+}
+
+void AuthKey::countKeyId() {
+	auto sha1 = hashSha1(_key.data(), _key.size());
+
+	// Lower 64 bits = 8 bytes of 20 byte SHA1 hash.
+	_keyId = *reinterpret_cast<KeyId*>(sha1.data() + 12);
+}
+
 void aesIgeEncryptRaw(const void *src, void *dst, uint32 len, const void *key, const void *iv) {
 	uchar aes_key[32], aes_iv[32];
 	memcpy(aes_key, key, 32);
diff --git a/Telegram/SourceFiles/mtproto/auth_key.h b/Telegram/SourceFiles/mtproto/auth_key.h
index cf8f7169e..dcfae3244 100644
--- a/Telegram/SourceFiles/mtproto/auth_key.h
+++ b/Telegram/SourceFiles/mtproto/auth_key.h
@@ -7,9 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "base/bytes.h"
 #include <array>
 #include <memory>
-#include "base/bytes.h"
 
 namespace MTP {
 
@@ -24,65 +24,29 @@ public:
 		ReadFromFile,
 		Local,
 	};
-	AuthKey(Type type, DcId dcId, const Data &data) : _type(type), _dcId(dcId), _key(data) {
-		countKeyId();
-	}
-	AuthKey(const Data &data) : _type(Type::Local), _key(data) {
-		countKeyId();
-	}
+	AuthKey(Type type, DcId dcId, const Data &data);
+	explicit AuthKey(const Data &data);
 
 	AuthKey(const AuthKey &other) = delete;
 	AuthKey &operator=(const AuthKey &other) = delete;
 
-	Type type() const {
-		return _type;
-	}
-
-	int dcId() const {
-		return _dcId;
-	}
-
-	KeyId keyId() const {
-		return _keyId;
-	}
+	Type type() const;
+	int dcId() const;
+	KeyId keyId() const;
 
 	void prepareAES_oldmtp(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const;
 	void prepareAES(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const;
 
-	const void *partForMsgKey(bool send) const {
-		return _key.data() + 88 + (send ? 0 : 8);
-	}
+	const void *partForMsgKey(bool send) const;
 
-	void write(QDataStream &to) const {
-		to.writeRawData(reinterpret_cast<const char*>(_key.data()), _key.size());
-	}
-	bytes::const_span data() const {
-		return _key;
-	}
+	void write(QDataStream &to) const;
+	bytes::const_span data() const;
+	bool equals(const std::shared_ptr<AuthKey> &other) const;
 
-	bool equals(const std::shared_ptr<AuthKey> &other) const {
-		return other ? (_key == other->_key) : false;
-	}
-
-	static void FillData(Data &authKey, bytes::const_span computedAuthKey) {
-		auto computedAuthKeySize = computedAuthKey.size();
-		Assert(computedAuthKeySize <= kSize);
-		auto authKeyBytes = gsl::make_span(authKey);
-		if (computedAuthKeySize < kSize) {
-			bytes::set_with_const(authKeyBytes.subspan(0, kSize - computedAuthKeySize), gsl::byte());
-			bytes::copy(authKeyBytes.subspan(kSize - computedAuthKeySize), computedAuthKey);
-		} else {
-			bytes::copy(authKeyBytes, computedAuthKey);
-		}
-	}
+	static void FillData(Data &authKey, bytes::const_span computedAuthKey);
 
 private:
-	void countKeyId() {
-		auto sha1 = hashSha1(_key.data(), _key.size());
-
-		// Lower 64 bits = 8 bytes of 20 byte SHA1 hash.
-		_keyId = *reinterpret_cast<KeyId*>(sha1.data() + 12);
-	}
+	void countKeyId();
 
 	Type _type = Type::Generated;
 	DcId _dcId = 0;
diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
index a17e7031f..1d687bbdb 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
+++ b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "mtproto/mtp_instance.h"
 #include "mtproto/rpc_sender.h"
+#include "mtproto/facade.h"
 
 namespace MTP {
 
diff --git a/Telegram/SourceFiles/mtproto/config_loader.cpp b/Telegram/SourceFiles/mtproto/config_loader.cpp
index 7abc822cc..3f60590a5 100644
--- a/Telegram/SourceFiles/mtproto/config_loader.cpp
+++ b/Telegram/SourceFiles/mtproto/config_loader.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/config_loader.h"
 
+#include "mtproto/facade.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/mtp_instance.h"
 #include "mtproto/special_config_request.h"
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 90b8d2056..c52b3aa7b 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -1187,7 +1187,7 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 	if (_testConnections.empty()) {
 		if (_instance->isKeysDestroyer()) {
 			LOG(("MTP Error: DC %1 options for not found for auth key destruction!").arg(_shiftedDcId));
-			emit _instance->keyDestroyed(_shiftedDcId);
+			_instance->checkIfKeyWasDestroyed(_shiftedDcId);
 			return;
 		} else if (afterConfig) {
 			LOG(("MTP Error: DC %1 options for not found right after config load!").arg(_shiftedDcId));
@@ -2606,7 +2606,7 @@ void ConnectionPrivate::updateAuthKey() 	{
 	} else if (_instance->isKeysDestroyer()) {
 		// We are here to destroy an old key, so we're done.
 		LOG(("MTP Error: No key %1 in updateAuthKey() for destroying.").arg(_shiftedDcId));
-		emit _instance->keyDestroyed(_shiftedDcId);
+		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
 		return;
 	}
 
@@ -3104,15 +3104,17 @@ void ConnectionPrivate::handleError(int errorCode) {
 	_waitForConnectedTimer.cancel();
 
 	if (errorCode == -404) {
-		if (_instance->isKeysDestroyer()) {
-			LOG(("MTP Info: -404 error received on destroying key %1, assuming it is destroyed.").arg(_shiftedDcId));
-			emit _instance->keyDestroyed(_shiftedDcId);
-			return;
-		} else if (_dcType == DcType::Cdn) {
+		if (_dcType == DcType::Cdn) {
 			LOG(("MTP Info: -404 error received in CDN dc %1, assuming it was destroyed, recreating.").arg(_shiftedDcId));
 			clearMessages();
 			keyId = kRecreateKeyId;
 			return restart();
+		} else {
+			LOG(("MTP Info: -404 error received, informing instance."));
+			_instance->checkIfKeyWasDestroyed(_shiftedDcId);
+			if (_instance->isKeysDestroyer()) {
+				return;
+			}
 		}
 	}
 	MTP_LOG(_shiftedDcId, ("Restarting after error in connection, error code: %1...").arg(errorCode));
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 3155ddbcf..d947e537d 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/auth_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/connection_abstract.h"
+#include "mtproto/facade.h"
 #include "base/openssl_help.h"
 #include "base/timer.h"
 
diff --git a/Telegram/SourceFiles/mtproto/connection_abstract.h b/Telegram/SourceFiles/mtproto/connection_abstract.h
index b524388e3..889fa831e 100644
--- a/Telegram/SourceFiles/mtproto/connection_abstract.h
+++ b/Telegram/SourceFiles/mtproto/connection_abstract.h
@@ -11,6 +11,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/bytes.h"
 
 namespace MTP {
+
+class Instance;
+
 namespace internal {
 
 struct ConnectionOptions;
diff --git a/Telegram/SourceFiles/mtproto/connection_resolving.cpp b/Telegram/SourceFiles/mtproto/connection_resolving.cpp
index 0822d009b..171b8885b 100644
--- a/Telegram/SourceFiles/mtproto/connection_resolving.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_resolving.cpp
@@ -7,6 +7,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/connection_resolving.h"
 
+#include "mtproto/mtp_instance.h"
+
 namespace MTP {
 namespace internal {
 namespace {
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index 4dda90416..54d15ca1c 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/dc_options.h"
 
+#include "mtproto/facade.h"
 #include "storage/serialize_common.h"
 #include "mtproto/connection_tcp.h"
 
diff --git a/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp b/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp
index 543418a20..c6ab7d640 100644
--- a/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp
+++ b/Telegram/SourceFiles/mtproto/dedicated_file_loader.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/dedicated_file_loader.h"
 
+#include "mtproto/facade.h"
 #include "main/main_session.h"
 #include "main/main_account.h" // Account::sessionChanges.
 #include "core/application.h"
diff --git a/Telegram/SourceFiles/mtproto/dedicated_file_loader.h b/Telegram/SourceFiles/mtproto/dedicated_file_loader.h
index a21769f2b..645f7e29e 100644
--- a/Telegram/SourceFiles/mtproto/dedicated_file_loader.h
+++ b/Telegram/SourceFiles/mtproto/dedicated_file_loader.h
@@ -7,9 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-namespace MTP {
+#include "mtproto/mtp_instance.h"
 
-class Instance;
+namespace MTP {
 
 class WeakInstance : private QObject, private base::Subscriber {
 public:
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 87f5b4f88..14ea8fae7 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -17,8 +17,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/rsa_public_key.h"
 #include "storage/localstorage.h"
 #include "calls/calls_instance.h"
-#include "main/main_account.h"
-#include "main/main_session.h"
+#include "main/main_session.h" // Session::Exists.
+#include "main/main_account.h" // Account::configUpdated.
 #include "apiwrap.h"
 #include "core/application.h"
 #include "lang/lang_instance.h"
@@ -26,7 +26,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/unixtime.h"
 #include "base/call_delayed.h"
 #include "base/timer.h"
-#include "facades.h"
+#include "facades.h" // Proxies list.
 
 namespace MTP {
 namespace {
@@ -246,10 +246,6 @@ void Instance::Private::start(Config &&config) {
 	_deviceModel = std::move(config.deviceModel);
 	_systemVersion = std::move(config.systemVersion);
 
-	if (isKeysDestroyer()) {
-		_instance->connect(_instance, SIGNAL(keyDestroyed(qint32)), _instance, SLOT(onKeyDestroyed(qint32)), Qt::QueuedConnection);
-	}
-
 	for (auto &key : config.keys) {
 		auto dcId = key->dcId();
 		auto shiftedDcId = dcId;
@@ -1487,10 +1483,10 @@ void Instance::Private::performKeyDestroy(ShiftedDcId shiftedDcId) {
 		} break;
 		case mtpc_destroy_auth_key_none: LOG(("MTP Info: key %1 already destroyed.").arg(shiftedDcId)); break;
 		}
-		emit _instance->keyDestroyed(shiftedDcId);
+		_instance->checkIfKeyWasDestroyed(shiftedDcId);
 	}), rpcFail([this, shiftedDcId](const RPCError &error) {
 		LOG(("MTP Error: key %1 destruction resulted in error: %2").arg(shiftedDcId).arg(error.type()));
-		emit _instance->keyDestroyed(shiftedDcId);
+		_instance->checkIfKeyWasDestroyed(shiftedDcId);
 		return true;
 	}), shiftedDcId);
 }
@@ -1749,9 +1745,16 @@ void Instance::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
 	_private->scheduleKeyDestroy(shiftedDcId);
 }
 
-void Instance::onKeyDestroyed(qint32 shiftedDcId) {
-	_private->completedKeyDestroy(shiftedDcId);
+void Instance::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
+	crl::on_main(this, [=] {
+		if (isKeysDestroyer()) {
+			LOG(("MTP Info: checkIfKeyWasDestroyed on destroying key %1, "
+				"assuming it is destroyed.").arg(shiftedDcId));
+			_private->completedKeyDestroy(shiftedDcId);
+		}
+	});
 }
+
 void Instance::sendRequest(
 		mtpRequestId requestId,
 		SecureRequest &&request,
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index c12d7432c..1e8424582 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -173,6 +173,7 @@ public:
 
 	bool isKeysDestroyer() const;
 	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
+	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
 
 	void requestConfig();
 	void requestConfigIfOld();
@@ -190,16 +191,12 @@ public slots:
 signals:
 	void configLoaded();
 	void cdnConfigLoaded();
-	void keyDestroyed(qint32 shiftedDcId);
 	void allKeysDestroyed();
 	void proxyDomainResolved(
 		QString host,
 		QStringList ips,
 		qint64 expireAt);
 
-private slots:
-	void onKeyDestroyed(qint32 shiftedDcId);
-
 private:
 	void sendRequest(
 		mtpRequestId requestId,
diff --git a/Telegram/SourceFiles/mtproto/sender.h b/Telegram/SourceFiles/mtproto/sender.h
index 37210d3fa..ab6521735 100644
--- a/Telegram/SourceFiles/mtproto/sender.h
+++ b/Telegram/SourceFiles/mtproto/sender.h
@@ -8,6 +8,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "base/variant.h"
+#include "mtproto/rpc_sender.h"
+#include "mtproto/mtp_instance.h"
+#include "mtproto/facade.h"
 
 namespace MTP {
 
diff --git a/Telegram/SourceFiles/stdafx.h b/Telegram/SourceFiles/stdafx.h
index 2f93879cf..0cc9711e8 100644
--- a/Telegram/SourceFiles/stdafx.h
+++ b/Telegram/SourceFiles/stdafx.h
@@ -120,7 +120,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/utils.h"
 #include "config.h"
 
-#include "mtproto/facade.h"
+#include "scheme.h"
+#include "mtproto/type_utils.h"
 
 #include "ui/style/style_core.h"
 #include "styles/palette.h"
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index 558a89bb4..c15d8745d 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "base/binary_guard.h"
 #include "data/data_file_origin.h"
+#include "mtproto/facade.h"
 
 #include <QtNetwork/QNetworkReply>
 
diff --git a/Telegram/SourceFiles/storage/file_upload.h b/Telegram/SourceFiles/storage/file_upload.h
index df6f3bc2c..7890845b2 100644
--- a/Telegram/SourceFiles/storage/file_upload.h
+++ b/Telegram/SourceFiles/storage/file_upload.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "api/api_common.h"
+#include "mtproto/facade.h"
 
 #include <QtCore/QTimer>
 
diff --git a/Telegram/SourceFiles/window/window_connecting_widget.cpp b/Telegram/SourceFiles/window/window_connecting_widget.cpp
index 718b17ba5..154614247 100644
--- a/Telegram/SourceFiles/window/window_connecting_widget.cpp
+++ b/Telegram/SourceFiles/window/window_connecting_widget.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/buttons.h"
 #include "ui/effects/radial_animation.h"
 #include "ui/ui_utility.h"
+#include "mtproto/facade.h"
 #include "window/themes/window_theme.h"
 #include "boxes/connection_box.h"
 #include "boxes/abstract_box.h"

From 70dbd9e5b4e0ffd1c8dee30597d1958ac5e957b4 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 13 Nov 2019 17:11:29 +0300
Subject: [PATCH 07/91] Add base::expected.

---
 .gitmodules                  | 3 +++
 Telegram/ThirdParty/expected | 1 +
 Telegram/lib_base            | 2 +-
 3 files changed, 5 insertions(+), 1 deletion(-)
 create mode 160000 Telegram/ThirdParty/expected

diff --git a/.gitmodules b/.gitmodules
index f51e8e319..c0880c9cd 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -49,3 +49,6 @@
 [submodule "Telegram/lib_spellcheck"]
 	path = Telegram/lib_spellcheck
 	url = https://github.com/desktop-app/lib_spellcheck
+[submodule "Telegram/ThirdParty/expected"]
+	path = Telegram/ThirdParty/expected
+	url = https://github.com/TartanLlama/expected
diff --git a/Telegram/ThirdParty/expected b/Telegram/ThirdParty/expected
new file mode 160000
index 000000000..1d9c5d8c0
--- /dev/null
+++ b/Telegram/ThirdParty/expected
@@ -0,0 +1 @@
+Subproject commit 1d9c5d8c0da84b8ddc54bd3d90d632eec95c1f13
diff --git a/Telegram/lib_base b/Telegram/lib_base
index 3aaab8850..c1941996f 160000
--- a/Telegram/lib_base
+++ b/Telegram/lib_base
@@ -1 +1 @@
-Subproject commit 3aaab885075b503950327e544316cd71a1412651
+Subproject commit c1941996febf02c4216a16fc6037e7473bcf9d00

From 08bfe6f1c1147cdcf57d58b02f0727bbf86c3537 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 13 Nov 2019 17:12:04 +0300
Subject: [PATCH 08/91] Extract mtproto key generation code.

---
 Telegram/SourceFiles/apiwrap.cpp              |   4 +-
 Telegram/SourceFiles/boxes/connection_box.cpp |   2 +
 Telegram/SourceFiles/boxes/connection_box.h   |   2 +
 Telegram/SourceFiles/calls/calls_call.cpp     |   6 +-
 Telegram/SourceFiles/calls/calls_instance.cpp |   2 +-
 Telegram/SourceFiles/core/application.cpp     |  12 +-
 Telegram/SourceFiles/core/application.h       |   9 +-
 .../SourceFiles/core/core_cloud_password.cpp  |   2 +-
 .../SourceFiles/core/crash_report_window.cpp  |   8 +-
 .../SourceFiles/core/crash_report_window.h    |   8 +-
 .../SourceFiles/core/local_url_handlers.cpp   |   8 +-
 Telegram/SourceFiles/core/sandbox.cpp         |  16 +-
 Telegram/SourceFiles/core/sandbox.h           |   6 +-
 Telegram/SourceFiles/core/utils.cpp           | 221 -----
 Telegram/SourceFiles/core/utils.h             |  44 -
 Telegram/SourceFiles/facades.cpp              |  12 +-
 Telegram/SourceFiles/facades.h                |   7 +-
 Telegram/SourceFiles/main/main_account.cpp    |   4 +-
 Telegram/SourceFiles/mtproto/connection.cpp   | 763 ++----------------
 Telegram/SourceFiles/mtproto/connection.h     |  74 +-
 .../mtproto/connection_abstract.cpp           |   7 +
 .../SourceFiles/mtproto/connection_abstract.h |  54 +-
 Telegram/SourceFiles/mtproto/dc_options.cpp   |  30 +-
 Telegram/SourceFiles/mtproto/dc_options.h     |   9 +-
 .../details/mtproto_dc_key_checker.cpp        |  31 +
 .../mtproto/details/mtproto_dc_key_checker.h  |  35 +
 .../details/mtproto_dc_key_creator.cpp        | 572 +++++++++++++
 .../mtproto/details/mtproto_dc_key_creator.h  | 102 +++
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  33 +-
 .../SourceFiles/mtproto/mtproto_dh_utils.cpp  | 173 ++++
 .../SourceFiles/mtproto/mtproto_dh_utils.h    |  35 +
 .../mtproto/mtproto_proxy_data.cpp            | 238 ++++++
 .../SourceFiles/mtproto/mtproto_proxy_data.h  |  58 ++
 .../SourceFiles/mtproto/rsa_public_key.cpp    | 285 ++++---
 Telegram/SourceFiles/mtproto/rsa_public_key.h |  15 +-
 Telegram/SourceFiles/mtproto/session.h        |   1 +
 .../settings/settings_advanced.cpp            |   2 +-
 Telegram/SourceFiles/storage/localstorage.cpp |  64 +-
 .../window/window_connecting_widget.cpp       |   2 +-
 Telegram/gyp/lib_mtproto.gyp                  |   8 +
 40 files changed, 1667 insertions(+), 1297 deletions(-)
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
 create mode 100644 Telegram/SourceFiles/mtproto/mtproto_dh_utils.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/mtproto_dh_utils.h
 create mode 100644 Telegram/SourceFiles/mtproto/mtproto_proxy_data.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/mtproto_proxy_data.h

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index b33afa76a..df32f7241 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -280,11 +280,11 @@ void ApiWrap::refreshProxyPromotion() {
 		return;
 	}
 	const auto key = [&]() -> std::pair<QString, uint32> {
-		if (Global::ProxySettings() != ProxyData::Settings::Enabled) {
+		if (Global::ProxySettings() != MTP::ProxyData::Settings::Enabled) {
 			return {};
 		}
 		const auto &proxy = Global::SelectedProxy();
-		if (proxy.type != ProxyData::Type::Mtproto) {
+		if (proxy.type != MTP::ProxyData::Type::Mtproto) {
 			return {};
 		}
 		return { proxy.host, proxy.port };
diff --git a/Telegram/SourceFiles/boxes/connection_box.cpp b/Telegram/SourceFiles/boxes/connection_box.cpp
index 663739f26..2b9cd94cb 100644
--- a/Telegram/SourceFiles/boxes/connection_box.cpp
+++ b/Telegram/SourceFiles/boxes/connection_box.cpp
@@ -38,6 +38,8 @@ namespace {
 
 constexpr auto kSaveSettingsDelayedTimeout = crl::time(1000);
 
+using ProxyData = MTP::ProxyData;
+
 class Base64UrlInput : public Ui::MaskedInputField {
 public:
 	Base64UrlInput(
diff --git a/Telegram/SourceFiles/boxes/connection_box.h b/Telegram/SourceFiles/boxes/connection_box.h
index 37e7040f2..21d79f9ad 100644
--- a/Telegram/SourceFiles/boxes/connection_box.h
+++ b/Telegram/SourceFiles/boxes/connection_box.h
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "base/object_ptr.h"
 #include "mtproto/connection_abstract.h"
+#include "mtproto/mtproto_proxy_data.h"
 
 namespace Ui {
 class BoxContent;
@@ -25,6 +26,7 @@ class Radioenum;
 
 class ProxiesBoxController : public base::Subscriber {
 public:
+	using ProxyData = MTP::ProxyData;
 	using Type = ProxyData::Type;
 
 	ProxiesBoxController();
diff --git a/Telegram/SourceFiles/calls/calls_call.cpp b/Telegram/SourceFiles/calls/calls_call.cpp
index 428ebf94f..7539f1544 100644
--- a/Telegram/SourceFiles/calls/calls_call.cpp
+++ b/Telegram/SourceFiles/calls/calls_call.cpp
@@ -14,7 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/rate_call_box.h"
 #include "calls/calls_instance.h"
 #include "base/openssl_help.h"
-#include "mtproto/connection.h"
+#include "mtproto/mtproto_dh_utils.h"
 #include "media/audio/media_audio_track.h"
 #include "base/platform/base_platform_info.h"
 #include "calls/calls_panel.h"
@@ -623,10 +623,10 @@ void Call::createAndStartController(const MTPDphoneCall &call) {
 	_controller->SetEncryptionKey(reinterpret_cast<char*>(_authKey.data()), (_type == Type::Outgoing));
 	_controller->SetCallbacks(callbacks);
 	if (Global::UseProxyForCalls()
-		&& (Global::ProxySettings() == ProxyData::Settings::Enabled)) {
+		&& (Global::ProxySettings() == MTP::ProxyData::Settings::Enabled)) {
 		const auto &proxy = Global::SelectedProxy();
 		if (proxy.supportsCalls()) {
-			Assert(proxy.type == ProxyData::Type::Socks5);
+			Assert(proxy.type == MTP::ProxyData::Type::Socks5);
 			_controller->SetProxy(
 				tgvoip::PROXY_SOCKS5,
 				proxy.host.toStdString(),
diff --git a/Telegram/SourceFiles/calls/calls_instance.cpp b/Telegram/SourceFiles/calls/calls_instance.cpp
index 5154c8019..7da4cef5e 100644
--- a/Telegram/SourceFiles/calls/calls_instance.cpp
+++ b/Telegram/SourceFiles/calls/calls_instance.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "calls/calls_instance.h"
 
-#include "mtproto/connection.h"
+#include "mtproto/mtproto_dh_utils.h"
 #include "core/application.h"
 #include "main/main_session.h"
 #include "apiwrap.h"
diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index bd74ebb48..916af7b22 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -370,12 +370,12 @@ void Application::saveSettingsDelayed(crl::time delay) {
 }
 
 void Application::setCurrentProxy(
-		const ProxyData &proxy,
-		ProxyData::Settings settings) {
+		const MTP::ProxyData &proxy,
+		MTP::ProxyData::Settings settings) {
 	const auto current = [&] {
-		return (Global::ProxySettings() == ProxyData::Settings::Enabled)
+		return (Global::ProxySettings() == MTP::ProxyData::Settings::Enabled)
 			? Global::SelectedProxy()
-			: ProxyData();
+			: MTP::ProxyData();
 	};
 	const auto was = current();
 	Global::SetSelectedProxy(proxy);
@@ -391,12 +391,12 @@ auto Application::proxyChanges() const -> rpl::producer<ProxyChange> {
 }
 
 void Application::badMtprotoConfigurationError() {
-	if (Global::ProxySettings() == ProxyData::Settings::Enabled
+	if (Global::ProxySettings() == MTP::ProxyData::Settings::Enabled
 		&& !_badProxyDisableBox) {
 		const auto disableCallback = [=] {
 			setCurrentProxy(
 				Global::SelectedProxy(),
-				ProxyData::Settings::System);
+				MTP::ProxyData::Settings::System);
 		};
 		_badProxyDisableBox = Ui::show(Box<InformBox>(
 			Lang::Hard::ProxyConfigError(),
diff --git a/Telegram/SourceFiles/core/application.h b/Telegram/SourceFiles/core/application.h
index 6129e71bd..57f3ace71 100644
--- a/Telegram/SourceFiles/core/application.h
+++ b/Telegram/SourceFiles/core/application.h
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "core/core_settings.h"
 #include "mtproto/auth_key.h"
+#include "mtproto/mtproto_proxy_data.h"
 #include "base/observer.h"
 #include "base/timer.h"
 
@@ -131,12 +132,12 @@ public:
 		return _dcOptions.get();
 	}
 	struct ProxyChange {
-		ProxyData was;
-		ProxyData now;
+		MTP::ProxyData was;
+		MTP::ProxyData now;
 	};
 	void setCurrentProxy(
-		const ProxyData &proxy,
-		ProxyData::Settings settings);
+		const MTP::ProxyData &proxy,
+		MTP::ProxyData::Settings settings);
 	[[nodiscard]] rpl::producer<ProxyChange> proxyChanges() const;
 	void badMtprotoConfigurationError();
 
diff --git a/Telegram/SourceFiles/core/core_cloud_password.cpp b/Telegram/SourceFiles/core/core_cloud_password.cpp
index 982154a96..22b14a717 100644
--- a/Telegram/SourceFiles/core/core_cloud_password.cpp
+++ b/Telegram/SourceFiles/core/core_cloud_password.cpp
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/core_cloud_password.h"
 
 #include "base/openssl_help.h"
-#include "mtproto/connection.h"
+#include "mtproto/mtproto_dh_utils.h"
 
 namespace Core {
 namespace {
diff --git a/Telegram/SourceFiles/core/crash_report_window.cpp b/Telegram/SourceFiles/core/crash_report_window.cpp
index 68ba1d90a..44ee32d85 100644
--- a/Telegram/SourceFiles/core/crash_report_window.cpp
+++ b/Telegram/SourceFiles/core/crash_report_window.cpp
@@ -814,10 +814,10 @@ void LastCrashedWindow::onNetworkSettingsSaved(
 		QString password) {
 	Expects(host.isEmpty() || port != 0);
 
-	auto proxy = ProxyData();
+	auto proxy = MTP::ProxyData();
 	proxy.type = host.isEmpty()
-		? ProxyData::Type::None
-		: ProxyData::Type::Http;
+		? MTP::ProxyData::Type::None
+		: MTP::ProxyData::Type::Http;
 	proxy.host = host;
 	proxy.port = port;
 	proxy.user = username;
@@ -843,7 +843,7 @@ void LastCrashedWindow::proxyUpdated() {
 	activate();
 }
 
-rpl::producer<ProxyData> LastCrashedWindow::proxyChanges() const {
+rpl::producer<MTP::ProxyData> LastCrashedWindow::proxyChanges() const {
 	return _proxyChanges.events();
 }
 
diff --git a/Telegram/SourceFiles/core/crash_report_window.h b/Telegram/SourceFiles/core/crash_report_window.h
index 59b4ac72f..16507c744 100644
--- a/Telegram/SourceFiles/core/crash_report_window.h
+++ b/Telegram/SourceFiles/core/crash_report_window.h
@@ -16,6 +16,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtNetwork/QHttpMultiPart>
 #include <QtNetwork/QNetworkAccessManager>
 
+namespace MTP {
+struct ProxyData;
+} // namespace MTP
+
 namespace Core {
 class Launcher;
 } // namespace Core
@@ -96,7 +100,7 @@ public:
 		const QByteArray &crashdump,
 		Fn<void()> launch);
 
-	rpl::producer<ProxyData> proxyChanges() const;
+	rpl::producer<MTP::ProxyData> proxyChanges() const;
 
 	rpl::lifetime &lifetime() {
 		return _lifetime;
@@ -199,7 +203,7 @@ private:
 	void setDownloadProgress(qint64 ready, qint64 total);
 
 	Fn<void()> _launch;
-	rpl::event_stream<ProxyData> _proxyChanges;
+	rpl::event_stream<MTP::ProxyData> _proxyChanges;
 	rpl::lifetime _lifetime;
 
 };
diff --git a/Telegram/SourceFiles/core/local_url_handlers.cpp b/Telegram/SourceFiles/core/local_url_handlers.cpp
index f19f54a24..b72822231 100644
--- a/Telegram/SourceFiles/core/local_url_handlers.cpp
+++ b/Telegram/SourceFiles/core/local_url_handlers.cpp
@@ -163,7 +163,9 @@ bool ApplySocksProxy(
 	auto params = url_parse_params(
 		match->captured(1),
 		qthelp::UrlParamNameTransform::ToLower);
-	ProxiesBoxController::ShowApplyConfirmation(ProxyData::Type::Socks5, params);
+	ProxiesBoxController::ShowApplyConfirmation(
+		MTP::ProxyData::Type::Socks5,
+		params);
 	return true;
 }
 
@@ -174,7 +176,9 @@ bool ApplyMtprotoProxy(
 	auto params = url_parse_params(
 		match->captured(1),
 		qthelp::UrlParamNameTransform::ToLower);
-	ProxiesBoxController::ShowApplyConfirmation(ProxyData::Type::Mtproto, params);
+	ProxiesBoxController::ShowApplyConfirmation(
+		MTP::ProxyData::Type::Mtproto,
+		params);
 	return true;
 }
 
diff --git a/Telegram/SourceFiles/core/sandbox.cpp b/Telegram/SourceFiles/core/sandbox.cpp
index 6f255a94c..762fd66d6 100644
--- a/Telegram/SourceFiles/core/sandbox.cpp
+++ b/Telegram/SourceFiles/core/sandbox.cpp
@@ -329,7 +329,7 @@ void Sandbox::singleInstanceChecked() {
 			_lastCrashDump,
 			[=] { launchApplication(); });
 		window->proxyChanges(
-		) | rpl::start_with_next([=](ProxyData &&proxy) {
+		) | rpl::start_with_next([=](MTP::ProxyData &&proxy) {
 			_sandboxProxy = std::move(proxy);
 			refreshGlobalProxy();
 		}, window->lifetime());
@@ -443,15 +443,15 @@ void Sandbox::refreshGlobalProxy() {
 #ifndef TDESKTOP_DISABLE_NETWORK_PROXY
 	const auto proxy = !Global::started()
 		? _sandboxProxy
-		: (Global::ProxySettings() == ProxyData::Settings::Enabled)
+		: (Global::ProxySettings() == MTP::ProxyData::Settings::Enabled)
 		? Global::SelectedProxy()
-		: ProxyData();
-	if (proxy.type == ProxyData::Type::Socks5
-		|| proxy.type == ProxyData::Type::Http) {
+		: MTP::ProxyData();
+	if (proxy.type == MTP::ProxyData::Type::Socks5
+		|| proxy.type == MTP::ProxyData::Type::Http) {
 		QNetworkProxy::setApplicationProxy(
-			ToNetworkProxy(ToDirectIpProxy(proxy)));
+			MTP::ToNetworkProxy(MTP::ToDirectIpProxy(proxy)));
 	} else if (!Global::started()
-		|| Global::ProxySettings() == ProxyData::Settings::System) {
+		|| Global::ProxySettings() == MTP::ProxyData::Settings::System) {
 		QNetworkProxyFactory::setUseSystemConfiguration(true);
 	} else {
 		QNetworkProxy::setApplicationProxy(QNetworkProxy::NoProxy);
@@ -555,7 +555,7 @@ rpl::producer<> Sandbox::widgetUpdateRequests() const {
 	return _widgetUpdateRequests.events();
 }
 
-ProxyData Sandbox::sandboxProxy() const {
+MTP::ProxyData Sandbox::sandboxProxy() const {
 	return _sandboxProxy;
 }
 
diff --git a/Telegram/SourceFiles/core/sandbox.h b/Telegram/SourceFiles/core/sandbox.h
index 7719f8419..f2b591706 100644
--- a/Telegram/SourceFiles/core/sandbox.h
+++ b/Telegram/SourceFiles/core/sandbox.h
@@ -7,6 +7,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "mtproto/mtproto_proxy_data.h"
+
 #include <QtWidgets/QApplication>
 #include <QtNetwork/QLocalServer>
 #include <QtNetwork/QLocalSocket>
@@ -50,7 +52,7 @@ public:
 
 	rpl::producer<> widgetUpdateRequests() const;
 
-	ProxyData sandboxProxy() const;
+	MTP::ProxyData sandboxProxy() const;
 
 	static Sandbox &Instance() {
 		Expects(QCoreApplication::instance() != nullptr);
@@ -119,7 +121,7 @@ private:
 	std::unique_ptr<UpdateChecker> _updateChecker;
 
 	QByteArray _lastCrashDump;
-	ProxyData _sandboxProxy;
+	MTP::ProxyData _sandboxProxy;
 
 	rpl::event_stream<> _widgetUpdateRequests;
 
diff --git a/Telegram/SourceFiles/core/utils.cpp b/Telegram/SourceFiles/core/utils.cpp
index 54ded4de8..fd62a1716 100644
--- a/Telegram/SourceFiles/core/utils.cpp
+++ b/Telegram/SourceFiles/core/utils.cpp
@@ -62,128 +62,6 @@ namespace {
 
 std::atomic<int> GlobalAtomicRequestId = 0;
 
-[[nodiscard]] bool IsHexMtprotoPassword(const QString &password) {
-	const auto size = password.size();
-	if (size < 32 || size % 2 == 1) {
-		return false;
-	}
-	const auto bad = [](QChar ch) {
-		const auto code = ch.unicode();
-		return (code < 'a' || code > 'f')
-			&& (code < 'A' || code > 'F')
-			&& (code < '0' || code > '9');
-	};
-	const auto i = std::find_if(password.begin(), password.end(), bad);
-	return (i == password.end());
-}
-
-[[nodiscard]] ProxyData::Status HexMtprotoPasswordStatus(
-		const QString &password) {
-	const auto size = password.size() / 2;
-	const auto valid = (size == 16)
-		|| (size == 17 && (password[0] == 'd') && (password[1] == 'd'))
-		|| (size >= 21 && (password[0] == 'e') && (password[1] == 'e'));
-	if (valid) {
-		return ProxyData::Status::Valid;
-	} else if (size < 16) {
-		return ProxyData::Status::Invalid;
-	}
-	return ProxyData::Status::Unsupported;
-}
-
-[[nodiscard]] bytes::vector SecretFromHexMtprotoPassword(
-		const QString &password) {
-	Expects(password.size() % 2 == 0);
-
-	const auto size = password.size() / 2;
-	const auto fromHex = [](QChar ch) -> int {
-		const auto code = int(ch.unicode());
-		if (code >= '0' && code <= '9') {
-			return (code - '0');
-		} else if (code >= 'A' && code <= 'F') {
-			return 10 + (code - 'A');
-		} else if (ch >= 'a' && ch <= 'f') {
-			return 10 + (code - 'a');
-		}
-		Unexpected("Code in ProxyData fromHex.");
-	};
-	auto result = bytes::vector(size);
-	for (auto i = 0; i != size; ++i) {
-		const auto high = fromHex(password[2 * i]);
-		const auto low = fromHex(password[2 * i + 1]);
-		if (high < 0 || low < 0) {
-			return {};
-		}
-		result[i] = static_cast<bytes::type>(high * 16 + low);
-	}
-	return result;
-}
-
-[[nodiscard]] QStringRef Base64UrlInner(const QString &password) {
-	Expects(password.size() > 2);
-
-	// Skip one or two '=' at the end of the string.
-	return password.midRef(0, [&] {
-		auto result = password.size();
-		for (auto i = 0; i != 2; ++i) {
-			const auto prev = result - 1;
-			if (password[prev] != '=') {
-				break;
-			}
-			result = prev;
-		}
-		return result;
-	}());
-}
-
-[[nodiscard]] bool IsBase64UrlMtprotoPassword(const QString &password) {
-	const auto size = password.size();
-	if (size < 22 || size % 4 == 1) {
-		return false;
-	}
-	const auto bad = [](QChar ch) {
-		const auto code = ch.unicode();
-		return (code < 'a' || code > 'z')
-			&& (code < 'A' || code > 'Z')
-			&& (code < '0' || code > '9')
-			&& (code != '_')
-			&& (code != '-');
-	};
-	const auto inner = Base64UrlInner(password);
-	const auto begin = inner.data();
-	const auto end = begin + inner.size();
-	return (std::find_if(begin, end, bad) == end);
-}
-
-[[nodiscard]] ProxyData::Status Base64UrlMtprotoPasswordStatus(
-		const QString &password) {
-	const auto inner = Base64UrlInner(password);
-	const auto size = (inner.size() * 3) / 4;
-	const auto valid = (size == 16)
-		|| (size == 17
-			&& (password[0] == '3')
-			&& ((password[1] >= 'Q' && password[1] <= 'Z')
-				|| (password[1] >= 'a' && password[1] <= 'f')))
-		|| (size >= 21
-			&& (password[0] == '7')
-			&& (password[1] >= 'g')
-			&& (password[1] <= 'v'));
-	if (size < 16) {
-		return ProxyData::Status::Invalid;
-	} else if (valid) {
-		return ProxyData::Status::Valid;
-	}
-	return ProxyData::Status::Unsupported;
-}
-
-[[nodiscard]] bytes::vector SecretFromBase64UrlMtprotoPassword(
-		const QString &password) {
-	const auto result = QByteArray::fromBase64(
-		password.toLatin1(),
-		QByteArray::Base64UrlEncoding);
-	return bytes::make_vector(bytes::make_span(result));
-}
-
 } // namespace
 
 // Precise timing functions / rand init
@@ -248,105 +126,6 @@ namespace {
 	}
 }
 
-bool ProxyData::valid() const {
-	return status() == Status::Valid;
-}
-
-ProxyData::Status ProxyData::status() const {
-	if (type == Type::None || host.isEmpty() || !port) {
-		return Status::Invalid;
-	} else if (type == Type::Mtproto) {
-		return MtprotoPasswordStatus(password);
-	}
-	return Status::Valid;
-}
-
-bool ProxyData::supportsCalls() const {
-	return (type == Type::Socks5);
-}
-
-bool ProxyData::tryCustomResolve() const {
-	return (type == Type::Socks5 || type == Type::Mtproto)
-		&& !qthelp::is_ipv6(host)
-		&& !QRegularExpression(
-			qsl("^\\d+\\.\\d+\\.\\d+\\.\\d+$")
-		).match(host).hasMatch();
-}
-
-bytes::vector ProxyData::secretFromMtprotoPassword() const {
-	Expects(type == Type::Mtproto);
-
-	if (IsHexMtprotoPassword(password)) {
-		return SecretFromHexMtprotoPassword(password);
-	} else if (IsBase64UrlMtprotoPassword(password)) {
-		return SecretFromBase64UrlMtprotoPassword(password);
-	}
-	return {};
-}
-
-ProxyData::operator bool() const {
-	return valid();
-}
-
-bool ProxyData::operator==(const ProxyData &other) const {
-	if (!valid()) {
-		return !other.valid();
-	}
-	return (type == other.type)
-		&& (host == other.host)
-		&& (port == other.port)
-		&& (user == other.user)
-		&& (password == other.password);
-}
-
-bool ProxyData::operator!=(const ProxyData &other) const {
-	return !(*this == other);
-}
-
-bool ProxyData::ValidMtprotoPassword(const QString &password) {
-	return MtprotoPasswordStatus(password) == Status::Valid;
-}
-
-ProxyData::Status ProxyData::MtprotoPasswordStatus(const QString &password) {
-	if (IsHexMtprotoPassword(password)) {
-		return HexMtprotoPasswordStatus(password);
-	} else if (IsBase64UrlMtprotoPassword(password)) {
-		return Base64UrlMtprotoPasswordStatus(password);
-	}
-	return Status::Invalid;
-}
-
-ProxyData ToDirectIpProxy(const ProxyData &proxy, int ipIndex) {
-	if (!proxy.tryCustomResolve()
-		|| ipIndex < 0
-		|| ipIndex >= proxy.resolvedIPs.size()) {
-		return proxy;
-	}
-	return {
-		proxy.type,
-		proxy.resolvedIPs[ipIndex],
-		proxy.port,
-		proxy.user,
-		proxy.password
-	};
-}
-
-QNetworkProxy ToNetworkProxy(const ProxyData &proxy) {
-	if (proxy.type == ProxyData::Type::None) {
-		return QNetworkProxy::DefaultProxy;
-	} else if (proxy.type == ProxyData::Type::Mtproto) {
-		return QNetworkProxy::NoProxy;
-	}
-	return QNetworkProxy(
-		(proxy.type == ProxyData::Type::Socks5
-			? QNetworkProxy::Socks5Proxy
-			: QNetworkProxy::HttpProxy),
-		proxy.host,
-		proxy.port,
-		proxy.user,
-		proxy.password);
-}
-
 namespace ThirdParty {
 
 	void start() {
diff --git a/Telegram/SourceFiles/core/utils.h b/Telegram/SourceFiles/core/utils.h
index c219f036e..9a21cabce 100644
--- a/Telegram/SourceFiles/core/utils.h
+++ b/Telegram/SourceFiles/core/utils.h
@@ -218,50 +218,6 @@ enum DBIWorkMode {
 	dbiwmWindowOnly = 2,
 };
 
-struct ProxyData {
-	enum class Settings {
-		System,
-		Enabled,
-		Disabled,
-	};
-	enum class Type {
-		None,
-		Socks5,
-		Http,
-		Mtproto,
-	};
-	enum class Status {
-		Valid,
-		Unsupported,
-		Invalid,
-	};
-
-	Type type = Type::None;
-	QString host;
-	uint32 port = 0;
-	QString user, password;
-
-	std::vector<QString> resolvedIPs;
-	crl::time resolvedExpireAt = 0;
-
-	[[nodiscard]] bool valid() const;
-	[[nodiscard]] Status status() const;
-	[[nodiscard]] bool supportsCalls() const;
-	[[nodiscard]] bool tryCustomResolve() const;
-	[[nodiscard]] bytes::vector secretFromMtprotoPassword() const;
-	[[nodiscard]] explicit operator bool() const;
-	[[nodiscard]] bool operator==(const ProxyData &other) const;
-	[[nodiscard]] bool operator!=(const ProxyData &other) const;
-
-	[[nodiscard]] static bool ValidMtprotoPassword(const QString &password);
-	[[nodiscard]] static Status MtprotoPasswordStatus(
-		const QString &password);
-
-};
-
-ProxyData ToDirectIpProxy(const ProxyData &proxy, int ipIndex = 0);
-QNetworkProxy ToNetworkProxy(const ProxyData &proxy);
-
 static const int MatrixRowShift = 40000;
 
 inline int rowscount(int fullCount, int countPerRow) {
diff --git a/Telegram/SourceFiles/facades.cpp b/Telegram/SourceFiles/facades.cpp
index 19419045a..725130654 100644
--- a/Telegram/SourceFiles/facades.cpp
+++ b/Telegram/SourceFiles/facades.cpp
@@ -373,9 +373,9 @@ struct Data {
 	bool NotificationsDemoIsShown = false;
 
 	bool TryIPv6 = !Platform::IsWindows();
-	std::vector<ProxyData> ProxiesList;
-	ProxyData SelectedProxy;
-	ProxyData::Settings ProxySettings = ProxyData::Settings::System;
+	std::vector<MTP::ProxyData> ProxiesList;
+	MTP::ProxyData SelectedProxy;
+	MTP::ProxyData::Settings ProxySettings = MTP::ProxyData::Settings::System;
 	bool UseProxyForCalls = false;
 	base::Observable<void> ConnectionTypeChanged;
 
@@ -501,9 +501,9 @@ DefineVar(Global, Notify::ScreenCorner, NotificationsCorner);
 DefineVar(Global, bool, NotificationsDemoIsShown);
 
 DefineVar(Global, bool, TryIPv6);
-DefineVar(Global, std::vector<ProxyData>, ProxiesList);
-DefineVar(Global, ProxyData, SelectedProxy);
-DefineVar(Global, ProxyData::Settings, ProxySettings);
+DefineVar(Global, std::vector<MTP::ProxyData>, ProxiesList);
+DefineVar(Global, MTP::ProxyData, SelectedProxy);
+DefineVar(Global, MTP::ProxyData::Settings, ProxySettings);
 DefineVar(Global, bool, UseProxyForCalls);
 DefineRefVar(Global, base::Observable<void>, ConnectionTypeChanged);
 
diff --git a/Telegram/SourceFiles/facades.h b/Telegram/SourceFiles/facades.h
index 951764a2a..bfa29df18 100644
--- a/Telegram/SourceFiles/facades.h
+++ b/Telegram/SourceFiles/facades.h
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/observer.h"
 #include "base/call_delayed.h"
 #include "ui/effects/animation_value.h"
+#include "mtproto/mtproto_proxy_data.h"
 
 class History;
 
@@ -224,9 +225,9 @@ DeclareVar(Notify::ScreenCorner, NotificationsCorner);
 DeclareVar(bool, NotificationsDemoIsShown);
 
 DeclareVar(bool, TryIPv6);
-DeclareVar(std::vector<ProxyData>, ProxiesList);
-DeclareVar(ProxyData, SelectedProxy);
-DeclareVar(ProxyData::Settings, ProxySettings);
+DeclareVar(std::vector<MTP::ProxyData>, ProxiesList);
+DeclareVar(MTP::ProxyData, SelectedProxy);
+DeclareVar(MTP::ProxyData::Settings, ProxySettings);
 DeclareVar(bool, UseProxyForCalls);
 DeclareRefVar(base::Observable<void>, ConnectionTypeChanged);
 
diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index c0185388c..0f98bb2ea 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -35,8 +35,8 @@ void Account::watchProxyChanges() {
 
 	Core::App().proxyChanges(
 	) | rpl::start_with_next([=](const ProxyChange &change) {
-		const auto key = [&](const ProxyData &proxy) {
-			return (proxy.type == ProxyData::Type::Mtproto)
+		const auto key = [&](const MTP::ProxyData &proxy) {
+			return (proxy.type == MTP::ProxyData::Type::Mtproto)
 				? std::make_pair(proxy.host, proxy.port)
 				: std::make_pair(QString(), uint32(0));
 		};
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index c52b3aa7b..f48b90189 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/connection.h"
 
+#include "mtproto/details/mtproto_dc_key_creator.h"
 #include "mtproto/session.h"
 #include "mtproto/rsa_public_key.h"
 #include "mtproto/rpc_sender.h"
@@ -39,7 +40,6 @@ namespace {
 
 constexpr auto kRecreateKeyId = AuthKey::KeyId(0xFFFFFFFFFFFFFFFFULL);
 constexpr auto kIntSize = static_cast<int>(sizeof(mtpPrime));
-constexpr auto kMaxModExpSize = 256;
 constexpr auto kWaitForBetterTimeout = crl::time(2000);
 constexpr auto kMinConnectedTimeout = crl::time(1000);
 constexpr auto kMaxConnectedTimeout = crl::time(8000);
@@ -57,6 +57,8 @@ constexpr auto kRequestConfigTimeout = crl::time(8000);
 // Don't try to handle messages larger than this size.
 constexpr auto kMaxMessageLength = 16 * 1024 * 1024;
 
+using namespace details;
+
 QString LogIdsVector(const QVector<MTPlong> &ids) {
 	if (!ids.size()) return "[]";
 	auto idsStr = QString("[%1").arg(ids.cbegin()->v);
@@ -66,162 +68,6 @@ QString LogIdsVector(const QVector<MTPlong> &ids) {
 	return idsStr + "]";
 }
 
-bool IsGoodModExpFirst(
-		const openssl::BigNum &modexp,
-		const openssl::BigNum &prime) {
-	const auto diff = openssl::BigNum::Sub(prime, modexp);
-	if (modexp.failed() || prime.failed() || diff.failed()) {
-		return false;
-	}
-	constexpr auto kMinDiffBitsCount = 2048 - 64;
-	if (diff.isNegative()
-		|| diff.bitsSize() < kMinDiffBitsCount
-		|| modexp.bitsSize() < kMinDiffBitsCount
-		|| modexp.bytesSize() > kMaxModExpSize) {
-		return false;
-	}
-	return true;
-}
-
-bool IsPrimeAndGoodCheck(const openssl::BigNum &prime, int g) {
-	constexpr auto kGoodPrimeBitsCount = 2048;
-
-	if (prime.failed()
-		|| prime.isNegative()
-		|| prime.bitsSize() != kGoodPrimeBitsCount) {
-		LOG(("MTP Error: Bad prime bits count %1, expected %2."
-			).arg(prime.bitsSize()
-			).arg(kGoodPrimeBitsCount));
-		return false;
-	}
-
-	const auto context = openssl::Context();
-	if (!prime.isPrime(context)) {
-		LOG(("MTP Error: Bad prime."));
-		return false;
-	}
-
-	switch (g) {
-	case 2: {
-		const auto mod8 = prime.countModWord(8);
-		if (mod8 != 7) {
-			LOG(("BigNum PT Error: bad g value: %1, mod8: %2").arg(g).arg(mod8));
-			return false;
-		}
-	} break;
-	case 3: {
-		const auto mod3 = prime.countModWord(3);
-		if (mod3 != 2) {
-			LOG(("BigNum PT Error: bad g value: %1, mod3: %2").arg(g).arg(mod3));
-			return false;
-		}
-	} break;
-	case 4: break;
-	case 5: {
-		const auto mod5 = prime.countModWord(5);
-		if (mod5 != 1 && mod5 != 4) {
-			LOG(("BigNum PT Error: bad g value: %1, mod5: %2").arg(g).arg(mod5));
-			return false;
-		}
-	} break;
-	case 6: {
-		const auto mod24 = prime.countModWord(24);
-		if (mod24 != 19 && mod24 != 23) {
-			LOG(("BigNum PT Error: bad g value: %1, mod24: %2").arg(g).arg(mod24));
-			return false;
-		}
-	} break;
-	case 7: {
-		const auto mod7 = prime.countModWord(7);
-		if (mod7 != 3 && mod7 != 5 && mod7 != 6) {
-			LOG(("BigNum PT Error: bad g value: %1, mod7: %2").arg(g).arg(mod7));
-			return false;
-		}
-	} break;
-	default: {
-		LOG(("BigNum PT Error: bad g value: %1").arg(g));
-		return false;
-	} break;
-	}
-
-	if (!openssl::BigNum(prime).subWord(1).divWord(2).isPrime(context)) {
-		LOG(("MTP Error: Bad (prime - 1) / 2."));
-		return false;
-	}
-
-	return true;
-}
-
-bool IsPrimeAndGood(bytes::const_span primeBytes, int g) {
-	static constexpr unsigned char GoodPrime[] = {
-		0xC7, 0x1C, 0xAE, 0xB9, 0xC6, 0xB1, 0xC9, 0x04, 0x8E, 0x6C, 0x52, 0x2F, 0x70, 0xF1, 0x3F, 0x73,
-		0x98, 0x0D, 0x40, 0x23, 0x8E, 0x3E, 0x21, 0xC1, 0x49, 0x34, 0xD0, 0x37, 0x56, 0x3D, 0x93, 0x0F,
-		0x48, 0x19, 0x8A, 0x0A, 0xA7, 0xC1, 0x40, 0x58, 0x22, 0x94, 0x93, 0xD2, 0x25, 0x30, 0xF4, 0xDB,
-		0xFA, 0x33, 0x6F, 0x6E, 0x0A, 0xC9, 0x25, 0x13, 0x95, 0x43, 0xAE, 0xD4, 0x4C, 0xCE, 0x7C, 0x37,
-		0x20, 0xFD, 0x51, 0xF6, 0x94, 0x58, 0x70, 0x5A, 0xC6, 0x8C, 0xD4, 0xFE, 0x6B, 0x6B, 0x13, 0xAB,
-		0xDC, 0x97, 0x46, 0x51, 0x29, 0x69, 0x32, 0x84, 0x54, 0xF1, 0x8F, 0xAF, 0x8C, 0x59, 0x5F, 0x64,
-		0x24, 0x77, 0xFE, 0x96, 0xBB, 0x2A, 0x94, 0x1D, 0x5B, 0xCD, 0x1D, 0x4A, 0xC8, 0xCC, 0x49, 0x88,
-		0x07, 0x08, 0xFA, 0x9B, 0x37, 0x8E, 0x3C, 0x4F, 0x3A, 0x90, 0x60, 0xBE, 0xE6, 0x7C, 0xF9, 0xA4,
-		0xA4, 0xA6, 0x95, 0x81, 0x10, 0x51, 0x90, 0x7E, 0x16, 0x27, 0x53, 0xB5, 0x6B, 0x0F, 0x6B, 0x41,
-		0x0D, 0xBA, 0x74, 0xD8, 0xA8, 0x4B, 0x2A, 0x14, 0xB3, 0x14, 0x4E, 0x0E, 0xF1, 0x28, 0x47, 0x54,
-		0xFD, 0x17, 0xED, 0x95, 0x0D, 0x59, 0x65, 0xB4, 0xB9, 0xDD, 0x46, 0x58, 0x2D, 0xB1, 0x17, 0x8D,
-		0x16, 0x9C, 0x6B, 0xC4, 0x65, 0xB0, 0xD6, 0xFF, 0x9C, 0xA3, 0x92, 0x8F, 0xEF, 0x5B, 0x9A, 0xE4,
-		0xE4, 0x18, 0xFC, 0x15, 0xE8, 0x3E, 0xBE, 0xA0, 0xF8, 0x7F, 0xA9, 0xFF, 0x5E, 0xED, 0x70, 0x05,
-		0x0D, 0xED, 0x28, 0x49, 0xF4, 0x7B, 0xF9, 0x59, 0xD9, 0x56, 0x85, 0x0C, 0xE9, 0x29, 0x85, 0x1F,
-		0x0D, 0x81, 0x15, 0xF6, 0x35, 0xB1, 0x05, 0xEE, 0x2E, 0x4E, 0x15, 0xD0, 0x4B, 0x24, 0x54, 0xBF,
-		0x6F, 0x4F, 0xAD, 0xF0, 0x34, 0xB1, 0x04, 0x03, 0x11, 0x9C, 0xD8, 0xE3, 0xB9, 0x2F, 0xCC, 0x5B };
-
-	if (!bytes::compare(bytes::make_span(GoodPrime), primeBytes)) {
-		if (g == 3 || g == 4 || g == 5 || g == 7) {
-			return true;
-		}
-	}
-
-	return IsPrimeAndGoodCheck(openssl::BigNum(primeBytes), g);
-}
-
-bytes::vector CreateAuthKey(
-		bytes::const_span firstBytes,
-		bytes::const_span randomBytes,
-		bytes::const_span primeBytes) {
-	using openssl::BigNum;
-
-	const auto first = BigNum(firstBytes);
-	const auto prime = BigNum(primeBytes);
-	if (!IsGoodModExpFirst(first, prime)) {
-		LOG(("AuthKey Error: Bad first prime in CreateAuthKey()."));
-		return {};
-	}
-	return BigNum::ModExp(first, BigNum(randomBytes), prime).getBytes();
-}
-
-ModExpFirst CreateModExp(
-		int g,
-		bytes::const_span primeBytes,
-		bytes::const_span randomSeed) {
-	Expects(randomSeed.size() == ModExpFirst::kRandomPowerSize);
-
-	using namespace openssl;
-
-	BigNum prime(primeBytes);
-	auto result = ModExpFirst();
-	result.randomPower.resize(ModExpFirst::kRandomPowerSize);
-	while (true) {
-		bytes::set_random(result.randomPower);
-		for (auto i = 0; i != ModExpFirst::kRandomPowerSize; ++i) {
-			result.randomPower[i] ^= randomSeed[i];
-		}
-		const auto modexp = BigNum::ModExp(
-			BigNum(g),
-			BigNum(result.randomPower),
-			prime);
-		if (IsGoodModExpFirst(modexp, prime)) {
-			result.modexp = modexp.getBytes();
-			return result;
-		}
-	}
-}
-
 void wrapInvokeAfter(SecureRequest &to, const SecureRequest &from, const RequestMap &haveSent, int32 skipBeforeRequest = 0) {
 	const auto afterId = *(mtpMsgId*)(from->after->data() + 4);
 	const auto i = afterId ? haveSent.constFind(afterId) : haveSent.cend();
@@ -245,48 +91,6 @@ void wrapInvokeAfter(SecureRequest &to, const SecureRequest &from, const Request
 	}
 }
 
-bool parsePQ(const QByteArray &pqStr, QByteArray &pStr, QByteArray &qStr) {
-	if (pqStr.length() > 8) return false; // more than 64 bit pq
-
-	uint64 pq = 0, p, q;
-	const uchar *pqChars = (const uchar*)pqStr.constData();
-	for (uint32 i = 0, l = pqStr.length(); i < l; ++i) {
-		pq <<= 8;
-		pq |= (uint64)pqChars[i];
-	}
-	uint64 pqSqrt = (uint64)sqrtl((long double)pq), ySqr, y;
-	while (pqSqrt * pqSqrt > pq) --pqSqrt;
-	while (pqSqrt * pqSqrt < pq) ++pqSqrt;
-	for (ySqr = pqSqrt * pqSqrt - pq; ; ++pqSqrt, ySqr = pqSqrt * pqSqrt - pq) {
-		y = (uint64)sqrtl((long double)ySqr);
-		while (y * y > ySqr) --y;
-		while (y * y < ySqr) ++y;
-		if (!ySqr || y + pqSqrt >= pq) return false;
-		if (y * y == ySqr) {
-			p = pqSqrt + y;
-			q = (pqSqrt > y) ? (pqSqrt - y) : (y - pqSqrt);
-			break;
-		}
-	}
-	if (p > q) std::swap(p, q);
-
-	pStr.resize(4);
-	uchar *pChars = (uchar*)pStr.data();
-	for (uint32 i = 0; i < 4; ++i) {
-		*(pChars + 3 - i) = (uchar)(p & 0xFF);
-		p >>= 8;
-	}
-
-	qStr.resize(4);
-	uchar *qChars = (uchar*)qStr.data();
-	for (uint32 i = 0; i < 4; ++i) {
-		*(qChars + 3 - i) = (uchar)(q & 0xFF);
-		q >>= 8;
-	}
-
-	return true;
-}
-
 } // namespace
 
 Connection::Connection(not_null<Instance*> instance) : _instance(instance) {
@@ -411,6 +215,7 @@ void ConnectionPrivate::destroyAllConnections() {
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
 	_testConnections.clear();
+	_keyCreator = nullptr;
 	_connection = nullptr;
 }
 
@@ -1392,8 +1197,6 @@ void ConnectionPrivate::doDisconnect() {
 		}
 	}
 
-	clearAuthKeyData();
-
 	setState(DisconnectedState);
 	restarted = false;
 }
@@ -2568,7 +2371,7 @@ void ConnectionPrivate::removeTestConnection(
 		end(_testConnections));
 }
 
-void ConnectionPrivate::updateAuthKey() 	{
+void ConnectionPrivate::updateAuthKey() {
 	QReadLocker lockFinished(&sessionDataMutex);
 	if (!sessionData || !_connection) return;
 
@@ -2597,7 +2400,7 @@ void ConnectionPrivate::updateAuthKey() 	{
 	DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), will be creating auth_key"));
 	lockKey();
 
-	auto &key = sessionData->getKey();
+	const auto &key = sessionData->getKey();
 	if (key) {
 		if (keyId != key->keyId()) clearMessages();
 		keyId = key->keyId();
@@ -2609,19 +2412,49 @@ void ConnectionPrivate::updateAuthKey() 	{
 		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
 		return;
 	}
-
-	_authKeyData = std::make_unique<ConnectionPrivate::AuthKeyCreateData>();
-	_authKeyStrings = std::make_unique<ConnectionPrivate::AuthKeyCreateStrings>();
-	const auto nonce = _authKeyData->nonce = rand_value<MTPint128>();
-
-	connect(_connection, &AbstractConnection::receivedData, [=] {
-		pqAnswered();
-	});
-
-	DEBUG_LOG(("AuthKey Info: sending Req_pq..."));
 	lockFinished.unlock();
 
-	sendNotSecureRequest(MTPReq_pq_multi(nonce));
+	createDcKey();
+}
+
+void ConnectionPrivate::createDcKey() {
+	using Result = DcKeyCreator::Result;
+	using Error = DcKeyCreator::Error;
+	auto delegate = DcKeyCreator::Delegate();
+	delegate.done = [=](base::expected<Result, Error> result) {
+		_keyCreator = nullptr;
+
+		if (result) {
+			QReadLocker lockFinished(&sessionDataMutex);
+			if (!sessionData) return;
+
+			sessionData->setSalt(result->serverSalt);
+
+			auto authKey = std::move(result->key);
+
+			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(authKey->keyId()).arg(result->serverSalt));
+
+			sessionData->owner()->notifyKeyCreated(std::move(authKey)); // slot will call authKeyCreated()
+			sessionData->clear(_instance);
+			unlockKey();
+		} else if (result.error() == Error::UnknownPublicKey) {
+			if (_dcType == DcType::Cdn) {
+				LOG(("Warning: CDN public RSA key not found"));
+				requestCDNConfig();
+			} else {
+				LOG(("AuthKey Error: could not choose public RSA key"));
+				restart();
+			}
+		} else {
+			restart();
+		}
+	};
+	_keyCreator = std::make_unique<DcKeyCreator>(
+		BareDcId(_shiftedDcId),
+		getProtocolDcId(),
+		_connection.get(),
+		_instance->dcOptions(),
+		std::move(delegate));
 }
 
 void ConnectionPrivate::clearMessages() {
@@ -2630,410 +2463,8 @@ void ConnectionPrivate::clearMessages() {
 	}
 }
 
-void ConnectionPrivate::pqAnswered() {
-	disconnect(_connection, &AbstractConnection::receivedData, nullptr, nullptr);
-	DEBUG_LOG(("AuthKey Info: receiving Req_pq answer..."));
-
-	MTPReq_pq::ResponseType res_pq;
-	if (!readNotSecureResponse(res_pq)) {
-		return restart();
-	}
-
-	auto &res_pq_data = res_pq.c_resPQ();
-	if (res_pq_data.vnonce() != _authKeyData->nonce) {
-		LOG(("AuthKey Error: received nonce <> sent nonce (in res_pq)!"));
-		DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&res_pq_data.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-		return restart();
-	}
-
-	auto rsaKey = internal::RSAPublicKey();
-	if (!_instance->dcOptions()->getDcRSAKey(BareDcId(_shiftedDcId), res_pq.c_resPQ().vserver_public_key_fingerprints().v, &rsaKey)) {
-		if (_dcType == DcType::Cdn) {
-			LOG(("Warning: CDN public RSA key not found"));
-			requestCDNConfig();
-			return;
-		}
-		LOG(("AuthKey Error: could not choose public RSA key"));
-		return restart();
-	}
-	Assert(rsaKey.isValid());
-
-	_authKeyData->server_nonce = res_pq_data.vserver_nonce();
-	_authKeyData->new_nonce = rand_value<MTPint256>();
-
-	auto &pq = res_pq_data.vpq().v;
-	auto p = QByteArray();
-	auto q = QByteArray();
-	if (!internal::parsePQ(pq, p, q)) {
-		LOG(("AuthKey Error: could not factor pq!"));
-		DEBUG_LOG(("AuthKey Error: problematic pq: %1").arg(Logs::mb(pq.constData(), pq.length()).str()));
-		return restart();
-	}
-
-	auto p_q_inner = MTP_p_q_inner_data_dc(
-		res_pq_data.vpq(),
-		MTP_bytes(std::move(p)),
-		MTP_bytes(std::move(q)),
-		_authKeyData->nonce,
-		_authKeyData->server_nonce,
-		_authKeyData->new_nonce,
-		MTP_int(getProtocolDcId()));
-	auto dhEncString = encryptPQInnerRSA(p_q_inner, rsaKey);
-	if (dhEncString.empty()) {
-		return restart();
-	}
-
-	connect(_connection, &AbstractConnection::receivedData, [=] {
-		dhParamsAnswered();
-	});
-
-	DEBUG_LOG(("AuthKey Info: sending Req_DH_params..."));
-
-	sendNotSecureRequest(MTPReq_DH_params(
-		_authKeyData->nonce,
-		_authKeyData->server_nonce,
-		p_q_inner.c_p_q_inner_data_dc().vp(),
-		p_q_inner.c_p_q_inner_data_dc().vq(),
-		MTP_long(rsaKey.getFingerPrint()),
-		MTP_bytes(dhEncString)));
-}
-
-bytes::vector ConnectionPrivate::encryptPQInnerRSA(
-		const MTPP_Q_inner_data &data,
-		const internal::RSAPublicKey &key) {
-	auto p_q_inner_size = tl::count_length(data);
-	auto encSize = (p_q_inner_size >> 2) + 6;
-	if (encSize >= 65) {
-		auto tmp = mtpBuffer();
-		tmp.reserve(encSize);
-		data.write(tmp);
-		LOG(("AuthKey Error: too large data for RSA encrypt, size %1").arg(encSize * sizeof(mtpPrime)));
-		DEBUG_LOG(("AuthKey Error: bad data for RSA encrypt %1").arg(Logs::mb(&tmp[0], tmp.size() * 4).str()));
-		return {}; // can't be 255-byte string
-	}
-
-	auto encBuffer = mtpBuffer();
-	encBuffer.reserve(65); // 260 bytes
-	encBuffer.resize(6);
-	encBuffer[0] = 0;
-	data.write(encBuffer);
-
-	hashSha1(&encBuffer[6], p_q_inner_size, &encBuffer[1]);
-	if (encSize < 65) {
-		encBuffer.resize(65);
-		memset_rand(&encBuffer[encSize], (65 - encSize) * sizeof(mtpPrime));
-	}
-
-	auto bytes = bytes::make_span(encBuffer);
-	auto bytesToEncrypt = bytes.subspan(3, 256);
-	return key.encrypt(bytesToEncrypt);
-}
-
-void ConnectionPrivate::dhParamsAnswered() {
-	disconnect(_connection, &AbstractConnection::receivedData, nullptr, nullptr);
-	DEBUG_LOG(("AuthKey Info: receiving Req_DH_params answer..."));
-
-	MTPReq_DH_params::ResponseType res_DH_params;
-	if (!readNotSecureResponse(res_DH_params)) {
-		return restart();
-	}
-
-	switch (res_DH_params.type()) {
-	case mtpc_server_DH_params_ok: {
-		const auto &encDH(res_DH_params.c_server_DH_params_ok());
-		if (encDH.vnonce() != _authKeyData->nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_params_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&encDH.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-			return restart();
-		}
-		if (encDH.vserver_nonce() != _authKeyData->server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&encDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_authKeyData->server_nonce, 16).str()));
-			return restart();
-		}
-
-		auto &encDHStr = encDH.vencrypted_answer().v;
-		uint32 encDHLen = encDHStr.length(), encDHBufLen = encDHLen >> 2;
-		if ((encDHLen & 0x03) || encDHBufLen < 6) {
-			LOG(("AuthKey Error: bad encrypted data length %1 (in server_DH_params_ok)!").arg(encDHLen));
-			DEBUG_LOG(("AuthKey Error: received encrypted data %1").arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
-			return restart();
-		}
-
-		uint32 nlen = tl::count_length(_authKeyData->new_nonce), slen = tl::count_length(_authKeyData->server_nonce);
-		uchar tmp_aes[1024], sha1ns[20], sha1sn[20], sha1nn[20];
-		memcpy(tmp_aes, &_authKeyData->new_nonce, nlen);
-		memcpy(tmp_aes + nlen, &_authKeyData->server_nonce, slen);
-		memcpy(tmp_aes + nlen + slen, &_authKeyData->new_nonce, nlen);
-		memcpy(tmp_aes + nlen + slen + nlen, &_authKeyData->new_nonce, nlen);
-		hashSha1(tmp_aes, nlen + slen, sha1ns);
-		hashSha1(tmp_aes + nlen, nlen + slen, sha1sn);
-		hashSha1(tmp_aes + nlen + slen, nlen + nlen, sha1nn);
-
-		mtpBuffer decBuffer;
-		decBuffer.resize(encDHBufLen);
-
-		memcpy(_authKeyData->aesKey, sha1ns, 20);
-		memcpy(_authKeyData->aesKey + 20, sha1sn, 12);
-		memcpy(_authKeyData->aesIV, sha1sn + 12, 8);
-		memcpy(_authKeyData->aesIV + 8, sha1nn, 20);
-		memcpy(_authKeyData->aesIV + 28, &_authKeyData->new_nonce, 4);
-
-		aesIgeDecryptRaw(encDHStr.constData(), &decBuffer[0], encDHLen, _authKeyData->aesKey, _authKeyData->aesIV);
-
-		const mtpPrime *from(&decBuffer[5]), *to(from), *end(from + (encDHBufLen - 5));
-		MTPServer_DH_inner_data dh_inner;
-		if (!dh_inner.read(to, end)) {
-			LOG(("AuthKey Error: could not decrypt server_DH_inner_data!"));
-			return restart();
-		}
-		const auto &dh_inner_data(dh_inner.c_server_DH_inner_data());
-		if (dh_inner_data.vnonce() != _authKeyData->nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_inner_data)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&dh_inner_data.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-			return restart();
-		}
-		if (dh_inner_data.vserver_nonce() != _authKeyData->server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_inner_data)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&dh_inner_data.vserver_nonce(), 16).str()).arg(Logs::mb(&_authKeyData->server_nonce, 16).str()));
-			return restart();
-		}
-		uchar sha1Buffer[20];
-		if (memcmp(&decBuffer[0], hashSha1(&decBuffer[5], (to - from) * sizeof(mtpPrime), sha1Buffer), 20)) {
-			LOG(("AuthKey Error: sha1 hash of encrypted part did not match!"));
-			DEBUG_LOG(("AuthKey Error: sha1 did not match, server_nonce: %1, new_nonce %2, encrypted data %3").arg(Logs::mb(&_authKeyData->server_nonce, 16).str()).arg(Logs::mb(&_authKeyData->new_nonce, 16).str()).arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
-			return restart();
-		}
-		base::unixtime::update(dh_inner_data.vserver_time().v);
-
-		// check that dhPrime and (dhPrime - 1) / 2 are really prime
-		if (!IsPrimeAndGood(bytes::make_span(dh_inner_data.vdh_prime().v), dh_inner_data.vg().v)) {
-			LOG(("AuthKey Error: bad dh_prime primality!"));
-			return restart();
-		}
-
-		_authKeyStrings->dh_prime = bytes::make_vector(
-			dh_inner_data.vdh_prime().v);
-		_authKeyData->g = dh_inner_data.vg().v;
-		_authKeyStrings->g_a = bytes::make_vector(dh_inner_data.vg_a().v);
-		_authKeyData->retry_id = MTP_long(0);
-		_authKeyData->retries = 0;
-	} return dhClientParamsSend();
-
-	case mtpc_server_DH_params_fail: {
-		const auto &encDH(res_DH_params.c_server_DH_params_fail());
-		if (encDH.vnonce() != _authKeyData->nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_params_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&encDH.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-			return restart();
-		}
-		if (encDH.vserver_nonce() != _authKeyData->server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&encDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_authKeyData->server_nonce, 16).str()));
-			return restart();
-		}
-		uchar sha1Buffer[20];
-		if (encDH.vnew_nonce_hash() != *(MTPint128*)(hashSha1(&_authKeyData->new_nonce, 32, sha1Buffer) + 1)) {
-			LOG(("AuthKey Error: received new_nonce_hash did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash: %1, new_nonce: %2").arg(Logs::mb(&encDH.vnew_nonce_hash(), 16).str()).arg(Logs::mb(&_authKeyData->new_nonce, 32).str()));
-			return restart();
-		}
-		LOG(("AuthKey Error: server_DH_params_fail received!"));
-	} return restart();
-
-	}
-	LOG(("AuthKey Error: unknown server_DH_params received, typeId = %1").arg(res_DH_params.type()));
-	return restart();
-}
-
-void ConnectionPrivate::dhClientParamsSend() {
-	if (++_authKeyData->retries > 5) {
-		LOG(("AuthKey Error: could not create auth_key for %1 retries").arg(_authKeyData->retries - 1));
-		return restart();
-	}
-
-	// gen rand 'b'
-	auto randomSeed = bytes::vector(ModExpFirst::kRandomPowerSize);
-	bytes::set_random(randomSeed);
-	auto g_b_data = CreateModExp(_authKeyData->g, _authKeyStrings->dh_prime, randomSeed);
-	if (g_b_data.modexp.empty()) {
-		LOG(("AuthKey Error: could not generate good g_b."));
-		return restart();
-	}
-
-	auto computedAuthKey = CreateAuthKey(_authKeyStrings->g_a, g_b_data.randomPower, _authKeyStrings->dh_prime);
-	if (computedAuthKey.empty()) {
-		LOG(("AuthKey Error: could not generate auth_key."));
-		return restart();
-	}
-	AuthKey::FillData(_authKeyStrings->auth_key, computedAuthKey);
-
-	// count auth_key hashes - parts of sha1(auth_key)
-	auto auth_key_sha = hashSha1(_authKeyStrings->auth_key.data(), _authKeyStrings->auth_key.size());
-	memcpy(&_authKeyData->auth_key_aux_hash, auth_key_sha.data(), 8);
-	memcpy(&_authKeyData->auth_key_hash, auth_key_sha.data() + 12, 8);
-
-	auto client_dh_inner = MTP_client_DH_inner_data(_authKeyData->nonce, _authKeyData->server_nonce, _authKeyData->retry_id, MTP_bytes(g_b_data.modexp));
-
-	auto sdhEncString = encryptClientDHInner(client_dh_inner);
-
-	connect(_connection, &AbstractConnection::receivedData, [=] {
-		dhClientParamsAnswered();
-	});
-
-	DEBUG_LOG(("AuthKey Info: sending Req_client_DH_params..."));
-	sendNotSecureRequest(MTPSet_client_DH_params(
-		_authKeyData->nonce,
-		_authKeyData->server_nonce,
-		MTP_string(std::move(sdhEncString))));
-}
-
-std::string ConnectionPrivate::encryptClientDHInner(const MTPClient_DH_Inner_Data &data) {
-	auto client_dh_inner_size = tl::count_length(data);
-	auto encSize = (client_dh_inner_size >> 2) + 5;
-	auto encFullSize = encSize;
-	if (encSize & 0x03) {
-		encFullSize += 4 - (encSize & 0x03);
-	}
-
-	auto encBuffer = mtpBuffer();
-	encBuffer.reserve(encFullSize);
-	encBuffer.resize(5);
-	data.write(encBuffer);
-
-	hashSha1(&encBuffer[5], client_dh_inner_size, &encBuffer[0]);
-	if (encSize < encFullSize) {
-		encBuffer.resize(encFullSize);
-		memset_rand(&encBuffer[encSize], (encFullSize - encSize) * sizeof(mtpPrime));
-	}
-
-	auto sdhEncString = std::string(encFullSize * 4, ' ');
-
-	aesIgeEncryptRaw(&encBuffer[0], &sdhEncString[0], encFullSize * sizeof(mtpPrime), _authKeyData->aesKey, _authKeyData->aesIV);
-
-	return sdhEncString;
-}
-
-void ConnectionPrivate::dhClientParamsAnswered() {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData) return;
-
-	disconnect(_connection, &AbstractConnection::receivedData, nullptr, nullptr);
-	DEBUG_LOG(("AuthKey Info: receiving Req_client_DH_params answer..."));
-
-	MTPSet_client_DH_params::ResponseType res_client_DH_params;
-	if (!readNotSecureResponse(res_client_DH_params)) {
-		lockFinished.unlock();
-		return restart();
-	}
-
-	switch (res_client_DH_params.type()) {
-	case mtpc_dh_gen_ok: {
-		const auto &resDH(res_client_DH_params.c_dh_gen_ok());
-		if (resDH.vnonce() != _authKeyData->nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		if (resDH.vserver_nonce() != _authKeyData->server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_authKeyData->server_nonce, 16).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		_authKeyData->new_nonce_buf[32] = 1;
-		uchar sha1Buffer[20];
-		if (resDH.vnew_nonce_hash1() != *(MTPint128*)(hashSha1(_authKeyData->new_nonce_buf, 41, sha1Buffer) + 1)) {
-			LOG(("AuthKey Error: received new_nonce_hash1 did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash1: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash1(), 16).str()).arg(Logs::mb(_authKeyData->new_nonce_buf, 41).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-
-		uint64 salt1 = _authKeyData->new_nonce.l.l, salt2 = _authKeyData->server_nonce.l, serverSalt = salt1 ^ salt2;
-		sessionData->setSalt(serverSalt);
-
-		auto authKey = std::make_shared<AuthKey>(AuthKey::Type::Generated, BareDcId(_shiftedDcId), _authKeyStrings->auth_key);
-
-		DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(authKey->keyId()).arg(serverSalt));
-
-		sessionData->owner()->notifyKeyCreated(std::move(authKey)); // slot will call authKeyCreated()
-		sessionData->clear(_instance);
-		unlockKey();
-	} return;
-
-	case mtpc_dh_gen_retry: {
-		const auto &resDH(res_client_DH_params.c_dh_gen_retry());
-		if (resDH.vnonce() != _authKeyData->nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_retry)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		if (resDH.vserver_nonce() != _authKeyData->server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_retry)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_authKeyData->server_nonce, 16).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		_authKeyData->new_nonce_buf[32] = 2;
-		uchar sha1Buffer[20];
-		if (resDH.vnew_nonce_hash2() != *(MTPint128*)(hashSha1(_authKeyData->new_nonce_buf, 41, sha1Buffer) + 1)) {
-			LOG(("AuthKey Error: received new_nonce_hash2 did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash2: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash2(), 16).str()).arg(Logs::mb(_authKeyData->new_nonce_buf, 41).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		_authKeyData->retry_id = _authKeyData->auth_key_aux_hash;
-	} return dhClientParamsSend();
-
-	case mtpc_dh_gen_fail: {
-		const auto &resDH(res_client_DH_params.c_dh_gen_fail());
-		if (resDH.vnonce() != _authKeyData->nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_authKeyData->nonce, 16).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		if (resDH.vserver_nonce() != _authKeyData->server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_authKeyData->server_nonce, 16).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		_authKeyData->new_nonce_buf[32] = 3;
-		uchar sha1Buffer[20];
-		if (resDH.vnew_nonce_hash3() != *(MTPint128*)(hashSha1(_authKeyData->new_nonce_buf, 41, sha1Buffer) + 1)) {
-			LOG(("AuthKey Error: received new_nonce_hash3 did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash3: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash3(), 16).str()).arg(Logs::mb(_authKeyData->new_nonce_buf, 41).str()));
-
-			lockFinished.unlock();
-			return restart();
-		}
-		LOG(("AuthKey Error: dh_gen_fail received!"));
-	}
-
-		lockFinished.unlock();
-		return restart();
-
-	}
-	LOG(("AuthKey Error: unknown set_client_DH_params_answer received, typeId = %1").arg(res_client_DH_params.type()));
-
-	lockFinished.unlock();
-	return restart();
-}
-
 void ConnectionPrivate::authKeyCreated() {
-	clearAuthKeyData();
+	_keyCreator = nullptr;
 
 	connect(_connection, &AbstractConnection::receivedData, [=] {
 		handleReceived();
@@ -3052,33 +2483,6 @@ void ConnectionPrivate::authKeyCreated() {
 	emit needToSendAsync();
 }
 
-void ConnectionPrivate::clearAuthKeyData() {
-	auto zeroMemory = [](bytes::span bytes) {
-#ifdef Q_OS_WIN2
-		SecureZeroMemory(bytes.data(), bytes.size());
-#else // Q_OS_WIN
-		auto end = reinterpret_cast<char*>(bytes.data()) + bytes.size();
-		for (volatile auto p = reinterpret_cast<volatile char*>(bytes.data()); p != end; ++p) {
-			*p = 0;
-		}
-#endif // Q_OS_WIN
-	};
-	if (_authKeyData) {
-		zeroMemory(gsl::make_span(reinterpret_cast<gsl::byte*>(_authKeyData.get()), sizeof(AuthKeyCreateData)));
-		_authKeyData.reset();
-	}
-	if (_authKeyStrings) {
-		if (!_authKeyStrings->dh_prime.empty()) {
-			zeroMemory(_authKeyStrings->dh_prime);
-		}
-		if (!_authKeyStrings->g_a.empty()) {
-			zeroMemory(_authKeyStrings->g_a);
-		}
-		zeroMemory(_authKeyStrings->auth_key);
-		_authKeyStrings.reset();
-	}
-}
-
 void ConnectionPrivate::onError(
 		not_null<AbstractConnection*> connection,
 		qint32 errorCode) {
@@ -3104,7 +2508,7 @@ void ConnectionPrivate::handleError(int errorCode) {
 	_waitForConnectedTimer.cancel();
 
 	if (errorCode == -404) {
-		if (_dcType == DcType::Cdn) {
+		if (_dcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
 			LOG(("MTP Info: -404 error received in CDN dc %1, assuming it was destroyed, recreating.").arg(_shiftedDcId));
 			clearMessages();
 			keyId = kRecreateKeyId;
@@ -3124,44 +2528,6 @@ void ConnectionPrivate::handleError(int errorCode) {
 void ConnectionPrivate::onReadyData() {
 }
 
-template <typename Request>
-void ConnectionPrivate::sendNotSecureRequest(const Request &request) {
-	auto packet = _connection->prepareNotSecurePacket(
-		request,
-		base::unixtime::mtproto_msg_id());
-
-	DEBUG_LOG(("AuthKey Info: sending request, size: %1, time: %3"
-		).arg(packet.size() - 8
-		).arg(packet[5]));
-
-	const auto bytesSize = packet.size() * sizeof(mtpPrime);
-
-	_connection->sendData(std::move(packet));
-
-	onSentSome(bytesSize);
-}
-
-template <typename Response>
-bool ConnectionPrivate::readNotSecureResponse(Response &response) {
-	onReceivedSome();
-
-	if (_connection->received().empty()) {
-		LOG(("AuthKey Error: "
-			"trying to read response from empty received list"));
-		return false;
-	}
-
-	const auto buffer = std::move(_connection->received().front());
-	_connection->received().pop_front();
-
-	const auto answer = _connection->parseNotSecureResponse(buffer);
-	if (answer.empty()) {
-		return false;
-	}
-	auto from = answer.data();
-	return response.read(from, from + answer.size());
-}
-
 bool ConnectionPrivate::sendSecureRequest(
 		SecureRequest &&request,
 		bool needAnyResponse,
@@ -3299,8 +2665,10 @@ void ConnectionPrivate::unlockKey() {
 }
 
 ConnectionPrivate::~ConnectionPrivate() {
-	clearAuthKeyData();
-	Assert(_finished && _connection == nullptr && _testConnections.empty());
+	Expects(_finished);
+	Expects(!_connection);
+	Expects(_testConnections.empty());
+	Expects(!_keyCreator);
 }
 
 void ConnectionPrivate::stop() {
@@ -3316,29 +2684,4 @@ void ConnectionPrivate::stop() {
 }
 
 } // namespace internal
-
-bool IsPrimeAndGood(bytes::const_span primeBytes, int g) {
-	return internal::IsPrimeAndGood(primeBytes, g);
-}
-
-bool IsGoodModExpFirst(
-		const openssl::BigNum &modexp,
-		const openssl::BigNum &prime) {
-	return internal::IsGoodModExpFirst(modexp, prime);
-}
-
-ModExpFirst CreateModExp(
-		int g,
-		bytes::const_span primeBytes,
-		bytes::const_span randomSeed) {
-	return internal::CreateModExp(g, primeBytes, randomSeed);
-}
-
-bytes::vector CreateAuthKey(
-		bytes::const_span firstBytes,
-		bytes::const_span randomBytes,
-		bytes::const_span primeBytes) {
-	return internal::CreateAuthKey(firstBytes, randomBytes, primeBytes);
-}
-
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index d947e537d..e03a1815d 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -15,31 +15,15 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 
 namespace MTP {
+namespace details {
+class DcKeyCreator;
+} // namespace details
 
 // How much time to wait for some more requests, when sending msg acks.
 constexpr auto kAckSendWaiting = crl::time(10000);
 
 class Instance;
 
-[[nodiscard]] bool IsPrimeAndGood(bytes::const_span primeBytes, int g);
-struct ModExpFirst {
-	static constexpr auto kRandomPowerSize = 256;
-
-	bytes::vector modexp;
-	bytes::vector randomPower;
-};
-[[nodiscard]] bool IsGoodModExpFirst(
-	const openssl::BigNum &modexp,
-	const openssl::BigNum &prime);
-[[nodiscard]] ModExpFirst CreateModExp(
-	int g,
-	bytes::const_span primeBytes,
-	bytes::const_span randomSeed);
-[[nodiscard]] bytes::vector CreateAuthKey(
-	bytes::const_span firstBytes,
-	bytes::const_span randomBytes,
-	bytes::const_span primeBytes);
-
 namespace internal {
 
 class AbstractConnection;
@@ -139,11 +123,6 @@ public slots:
 
 	void onReadyData();
 
-	// Auth key creation packet receive slots
-	void pqAnswered();
-	void dhParamsAnswered();
-	void dhClientParamsAnswered();
-
 	// General packet receive slot, connected to conn->receivedData signal
 	void handleReceived();
 
@@ -214,8 +193,6 @@ private:
 
 	bool setState(int32 state, int32 ifState = Connection::UpdateAlways);
 
-	bytes::vector encryptPQInnerRSA(const MTPP_Q_inner_data &data, const internal::RSAPublicKey &key);
-	std::string encryptClientDHInner(const MTPClient_DH_Inner_Data &data);
 	void appendTestConnection(
 		DcOptions::Variants::Protocol protocol,
 		const QString &ip,
@@ -231,11 +208,11 @@ private:
 	void resend(quint64 msgId, qint64 msCanWait = 0, bool forceContainer = false, bool sendMsgStateInfo = false);
 	void resendMany(QVector<quint64> msgIds, qint64 msCanWait = 0, bool forceContainer = false, bool sendMsgStateInfo = false);
 
-	template <typename Request>
-	void sendNotSecureRequest(const Request &request);
-
-	template <typename Response>
-	[[nodiscard]] bool readNotSecureResponse(Response &response);
+	void createDcKey();
+	void resetSession();
+	void lockKey();
+	void unlockKey();
+	void authKeyCreated();
 
 	not_null<Instance*> _instance;
 	DcType _dcType = DcType::Regular;
@@ -244,7 +221,6 @@ private:
 	int32 _state = DisconnectedState;
 
 	bool _needSessionReset = false;
-	void resetSession();
 
 	ShiftedDcId _shiftedDcId = 0;
 	not_null<Connection*> _owner;
@@ -283,40 +259,8 @@ private:
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 
 	bool myKeyLock = false;
-	void lockKey();
-	void unlockKey();
 
-	// Auth key creation fields and methods
-	struct AuthKeyCreateData {
-		AuthKeyCreateData()
-		: new_nonce(*(MTPint256*)((uchar*)new_nonce_buf))
-		, auth_key_aux_hash(*(MTPlong*)((uchar*)new_nonce_buf + 33)) {
-		}
-		MTPint128 nonce, server_nonce;
-		uchar new_nonce_buf[41] = { 0 }; // 32 bytes new_nonce + 1 check byte + 8 bytes of auth_key_aux_hash
-		MTPint256 &new_nonce;
-		MTPlong &auth_key_aux_hash;
-
-		uint32 retries = 0;
-		MTPlong retry_id;
-
-		int32 g = 0;
-
-		uchar aesKey[32] = { 0 };
-		uchar aesIV[32] = { 0 };
-		MTPlong auth_key_hash;
-	};
-	struct AuthKeyCreateStrings {
-		bytes::vector dh_prime;
-		bytes::vector g_a;
-		AuthKey::Data auth_key = { { gsl::byte{} } };
-	};
-	std::unique_ptr<AuthKeyCreateData> _authKeyData;
-	std::unique_ptr<AuthKeyCreateStrings> _authKeyStrings;
-
-	void dhClientParamsSend();
-	void authKeyCreated();
-	void clearAuthKeyData();
+	std::unique_ptr<details::DcKeyCreator> _keyCreator;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/connection_abstract.cpp b/Telegram/SourceFiles/mtproto/connection_abstract.cpp
index 48974856d..831141c29 100644
--- a/Telegram/SourceFiles/mtproto/connection_abstract.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_abstract.cpp
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/connection_resolving.h"
 #include "mtproto/session.h"
 #include "base/unixtime.h"
+#include "base/openssl_help.h"
 
 namespace MTP {
 namespace internal {
@@ -187,5 +188,11 @@ ConnectionPointer AbstractConnection::Create(
 	return result;
 }
 
+uint32 AbstractConnection::extendedNotSecurePadding() const {
+	return requiresExtendedPadding()
+		? uint32(openssl::RandomValue<uchar>() & 0x3F)
+		: 0;
+}
+
 } // namespace internal
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_abstract.h b/Telegram/SourceFiles/mtproto/connection_abstract.h
index 889fa831e..802f9fbd9 100644
--- a/Telegram/SourceFiles/mtproto/connection_abstract.h
+++ b/Telegram/SourceFiles/mtproto/connection_abstract.h
@@ -8,8 +8,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/dc_options.h"
+#include "mtproto/mtproto_proxy_data.h"
 #include "base/bytes.h"
 
+#include <QtCore/QObject>
+#include <QtCore/QThread>
+
 namespace MTP {
 
 class Instance;
@@ -60,17 +64,17 @@ public:
 	virtual ~AbstractConnection() = default;
 
 	// virtual constructor
-	static ConnectionPointer Create(
+	[[nodiscard]] static ConnectionPointer Create(
 		not_null<Instance*> instance,
 		DcOptions::Variants::Protocol protocol,
 		QThread *thread,
 		const bytes::vector &secret,
 		const ProxyData &proxy);
 
-	virtual ConnectionPointer clone(const ProxyData &proxy) = 0;
+	[[nodiscard]] virtual ConnectionPointer clone(const ProxyData &proxy) = 0;
 
-	virtual crl::time pingTime() const = 0;
-	virtual crl::time fullConnectTimeout() const = 0;
+	[[nodiscard]] virtual crl::time pingTime() const = 0;
+	[[nodiscard]] virtual crl::time fullConnectTimeout() const = 0;
 	virtual void sendData(mtpBuffer &&buffer) = 0;
 	virtual void disconnectFromServer() = 0;
 	virtual void connectToServer(
@@ -80,41 +84,41 @@ public:
 		int16 protocolDcId) = 0;
 	virtual void timedOut() {
 	}
-	virtual bool isConnected() const = 0;
-	virtual bool usingHttpWait() {
+	[[nodiscard]] virtual bool isConnected() const = 0;
+	[[nodiscard]] virtual bool usingHttpWait() {
 		return false;
 	}
-	virtual bool needHttpWait() {
+	[[nodiscard]] virtual bool needHttpWait() {
 		return false;
 	}
-	virtual bool requiresExtendedPadding() const {
+	[[nodiscard]] virtual bool requiresExtendedPadding() const {
 		return false;
 	}
 
-	virtual int32 debugState() const = 0;
+	[[nodiscard]] virtual int32 debugState() const = 0;
 
-	virtual QString transport() const = 0;
-	virtual QString tag() const = 0;
+	[[nodiscard]] virtual QString transport() const = 0;
+	[[nodiscard]] virtual QString tag() const = 0;
 
 	void setSentEncrypted() {
 		_sentEncrypted = true;
 	}
 
 	using BuffersQueue = std::deque<mtpBuffer>;
-	BuffersQueue &received() {
+	[[nodiscard]] BuffersQueue &received() {
 		return _receivedQueue;
 	}
 
 	template <typename Request>
-	mtpBuffer prepareNotSecurePacket(
+	[[nodiscard]] mtpBuffer prepareNotSecurePacket(
 		const Request &request,
 		mtpMsgId newId) const;
-	mtpBuffer prepareSecurePacket(
+	[[nodiscard]] mtpBuffer prepareSecurePacket(
 		uint64 keyId,
 		MTPint128 msgKey,
 		uint32 size) const;
 
-	gsl::span<const mtpPrime> parseNotSecureResponse(
+	[[nodiscard]] gsl::span<const mtpPrime> parseNotSecureResponse(
 		const mtpBuffer &buffer) const;
 
 	// Used to emit error(...) with no real code from the server.
@@ -139,8 +143,12 @@ protected:
 
 	// first we always send fake MTPReq_pq to see if connection works at all
 	// we send them simultaneously through TCP/HTTP/IPv4/IPv6 to choose the working one
-	mtpBuffer preparePQFake(const MTPint128 &nonce) const;
-	std::optional<MTPResPQ> readPQFakeReply(const mtpBuffer &buffer) const;
+	[[nodiscard]] mtpBuffer preparePQFake(const MTPint128 &nonce) const;
+	[[nodiscard]] std::optional<MTPResPQ> readPQFakeReply(
+		const mtpBuffer &buffer) const;
+
+private:
+	[[nodiscard]] uint32 extendedNotSecurePadding() const;
 
 };
 
@@ -149,9 +157,7 @@ mtpBuffer AbstractConnection::prepareNotSecurePacket(
 		const Request &request,
 		mtpMsgId newId) const {
 	const auto intsSize = tl::count_length(request) >> 2;
-	const auto intsPadding = requiresExtendedPadding()
-		? uint32(rand_value<uchar>() & 0x3F)
-		: 0;
+	const auto intsPadding = extendedNotSecurePadding();
 
 	auto result = mtpBuffer();
 	constexpr auto kTcpPrefixInts = 2;
@@ -176,10 +182,10 @@ mtpBuffer AbstractConnection::prepareNotSecurePacket(
 	*messageLength = (result.size() - kPrefixInts + intsPadding) << 2;
 
 	if (intsPadding > 0) {
-		result.resize(result.size() + intsPadding);
-		memset_rand(
-			result.data() + result.size() - intsPadding,
-			intsPadding * sizeof(mtpPrime));
+		const auto skipPrimes = result.size();
+		result.resize(skipPrimes + intsPadding);
+		const auto skipBytes = skipPrimes * sizeof(mtpPrime);
+		bytes::set_random(bytes::make_span(result).subspan(skipBytes));
 	}
 
 	return result;
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index 54d15ca1c..a072048d4 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -105,8 +105,8 @@ void DcOptions::readBuiltInPublicKeys() {
 	for (const auto key : PublicRSAKeys) {
 		const auto keyBytes = bytes::make_span(key, strlen(key));
 		auto parsed = internal::RSAPublicKey(keyBytes);
-		if (parsed.isValid()) {
-			_publicKeys.emplace(parsed.getFingerPrint(), std::move(parsed));
+		if (parsed.valid()) {
+			_publicKeys.emplace(parsed.fingerprint(), std::move(parsed));
 		} else {
 			LOG(("MTP Error: could not read this public RSA key:"));
 			LOG((key));
@@ -505,8 +505,8 @@ void DcOptions::constructFromSerialized(const QByteArray &serialized) {
 			}
 
 			auto key = internal::RSAPublicKey(n, e);
-			if (key.isValid()) {
-				_cdnPublicKeys[dcId].emplace(key.getFingerPrint(), std::move(key));
+			if (key.valid()) {
+				_cdnPublicKeys[dcId].emplace(key.fingerprint(), std::move(key));
 			} else {
 				LOG(("MTP Error: Could not read valid CDN public key."));
 			}
@@ -554,9 +554,9 @@ void DcOptions::setCDNConfig(const MTPDcdnConfig &config) {
 		const auto &keyData = publicKey.c_cdnPublicKey();
 		const auto keyBytes = bytes::make_span(keyData.vpublic_key().v);
 		auto key = internal::RSAPublicKey(keyBytes);
-		if (key.isValid()) {
+		if (key.valid()) {
 			_cdnPublicKeys[keyData.vdc_id().v].emplace(
-				key.getFingerPrint(),
+				key.fingerprint(),
 				std::move(key));
 		} else {
 			LOG(("MTP Error: could not read this public RSA key:"));
@@ -570,20 +570,22 @@ bool DcOptions::hasCDNKeysForDc(DcId dcId) const {
 	return _cdnPublicKeys.find(dcId) != _cdnPublicKeys.cend();
 }
 
-bool DcOptions::getDcRSAKey(DcId dcId, const QVector<MTPlong> &fingerprints, internal::RSAPublicKey *result) const {
-	auto findKey = [&fingerprints, &result](const std::map<uint64, internal::RSAPublicKey> &keys) {
-		for_const (auto &fingerprint, fingerprints) {
-			auto it = keys.find(static_cast<uint64>(fingerprint.v));
+internal::RSAPublicKey DcOptions::getDcRSAKey(
+		DcId dcId,
+		const QVector<MTPlong> &fingerprints) const {
+	const auto findKey = [&](
+			const std::map<uint64, internal::RSAPublicKey> &keys) {
+		for (const auto &fingerprint : fingerprints) {
+			const auto it = keys.find(static_cast<uint64>(fingerprint.v));
 			if (it != keys.cend()) {
-				*result = it->second;
-				return true;
+				return it->second;
 			}
 		}
-		return false;
+		return internal::RSAPublicKey();
 	};
 	{
 		ReadLocker lock(this);
-		auto it = _cdnPublicKeys.find(dcId);
+		const auto it = _cdnPublicKeys.find(dcId);
 		if (it != _cdnPublicKeys.cend()) {
 			return findKey(it->second);
 		}
diff --git a/Telegram/SourceFiles/mtproto/dc_options.h b/Telegram/SourceFiles/mtproto/dc_options.h
index cbd20d68a..71d3dec85 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.h
+++ b/Telegram/SourceFiles/mtproto/dc_options.h
@@ -10,9 +10,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/observer.h"
 #include "base/bytes.h"
 #include "mtproto/rsa_public_key.h"
+
+#include <QtCore/QReadWriteLock>
 #include <string>
 #include <vector>
 #include <map>
+#include <set>
 
 namespace MTP {
 
@@ -90,8 +93,10 @@ public:
 	DcType dcType(ShiftedDcId shiftedDcId) const;
 
 	void setCDNConfig(const MTPDcdnConfig &config);
-	bool hasCDNKeysForDc(DcId dcId) const;
-	bool getDcRSAKey(DcId dcId, const QVector<MTPlong> &fingerprints, internal::RSAPublicKey *result) const;
+	[[nodiscard]] bool hasCDNKeysForDc(DcId dcId) const;
+	[[nodiscard]] internal::RSAPublicKey getDcRSAKey(
+		DcId dcId,
+		const QVector<MTPlong> &fingerprints) const;
 
 	// Debug feature for now.
 	bool loadFromFile(const QString &path);
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
new file mode 100644
index 000000000..54f713a20
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
@@ -0,0 +1,31 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/details/mtproto_dc_key_checker.h"
+
+#include "mtproto/mtp_instance.h"
+
+#include <QtCore/QPointer>
+
+namespace MTP::details {
+
+DcKeyChecker::DcKeyChecker(
+	not_null<Instance*> instance,
+	DcId dcId,
+	const AuthKeyPtr &key,
+	FnMut<void()> destroyMe)
+: _instance(instance)
+, _dcId(dcId)
+, _key(key)
+, _destroyMe(std::move(destroyMe)) {
+	crl::on_main(instance, [=] {
+		auto destroy = std::move(_destroyMe);
+		destroy();
+	});
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
new file mode 100644
index 000000000..08f631277
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
@@ -0,0 +1,35 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "mtproto/core_types.h"
+#include "mtproto/auth_key.h"
+
+namespace MTP {
+class Instance;
+} // namespace MTP
+
+namespace MTP::details {
+
+class DcKeyChecker final {
+public:
+	DcKeyChecker(
+		not_null<Instance*> instance,
+		DcId dcId,
+		const AuthKeyPtr &key,
+		FnMut<void()> destroyMe);
+
+private:
+	not_null<Instance*> _instance;
+	DcId _dcId = 0;
+	AuthKeyPtr _key;
+	FnMut<void()> _destroyMe;
+
+};
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
new file mode 100644
index 000000000..1f12d81ac
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -0,0 +1,572 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/details/mtproto_dc_key_creator.h"
+
+#include "mtproto/connection_abstract.h"
+#include "mtproto/mtproto_dh_utils.h"
+#include "base/openssl_help.h"
+#include "base/unixtime.h"
+#include "scheme.h"
+#include "logs.h"
+
+namespace MTP::details {
+namespace {
+
+struct ParsedPQ {
+	QByteArray p;
+	QByteArray q;
+};
+
+[[nodiscard]] ParsedPQ ParsePQ(const QByteArray &pqStr) {
+	if (pqStr.length() > 8) {
+		// More than 64 bit pq.
+		return ParsedPQ();
+	}
+
+	uint64 pq = 0, p, q;
+	const uchar *pqChars = (const uchar*)pqStr.constData();
+	for (uint32 i = 0, l = pqStr.length(); i < l; ++i) {
+		pq <<= 8;
+		pq |= (uint64)pqChars[i];
+	}
+	uint64 pqSqrt = (uint64)sqrtl((long double)pq), ySqr, y;
+	while (pqSqrt * pqSqrt > pq) --pqSqrt;
+	while (pqSqrt * pqSqrt < pq) ++pqSqrt;
+	for (ySqr = pqSqrt * pqSqrt - pq; ; ++pqSqrt, ySqr = pqSqrt * pqSqrt - pq) {
+		y = (uint64)sqrtl((long double)ySqr);
+		while (y * y > ySqr) --y;
+		while (y * y < ySqr) ++y;
+		if (!ySqr || y + pqSqrt >= pq) {
+			return ParsedPQ();
+		}
+		if (y * y == ySqr) {
+			p = pqSqrt + y;
+			q = (pqSqrt > y) ? (pqSqrt - y) : (y - pqSqrt);
+			break;
+		}
+	}
+	if (p > q) std::swap(p, q);
+
+	auto pStr = QByteArray(4, Qt::Uninitialized);
+	uchar *pChars = (uchar*)pStr.data();
+	for (uint32 i = 0; i < 4; ++i) {
+		*(pChars + 3 - i) = (uchar)(p & 0xFF);
+		p >>= 8;
+	}
+
+	auto qStr = QByteArray(4, Qt::Uninitialized);
+	uchar *qChars = (uchar*)qStr.data();
+	for (uint32 i = 0; i < 4; ++i) {
+		*(qChars + 3 - i) = (uchar)(q & 0xFF);
+		q >>= 8;
+	}
+
+	return { pStr, qStr };
+}
+
+[[nodiscard]] bytes::vector EncryptPQInnerRSA(
+		const MTPP_Q_inner_data &data,
+		const RSAPublicKey &key) {
+	constexpr auto kSkipPrimes = 6;
+	constexpr auto kMaxPrimes = 65; // 260 bytes
+
+	const auto p_q_inner_size = tl::count_length(data);
+	const auto sizeInPrimes = (p_q_inner_size >> 2) + kSkipPrimes;
+	if (sizeInPrimes >= kMaxPrimes) {
+		auto tmp = mtpBuffer();
+		tmp.reserve(sizeInPrimes);
+		data.write(tmp);
+		LOG(("AuthKey Error: too large data for RSA encrypt, size %1").arg(sizeInPrimes * sizeof(mtpPrime)));
+		DEBUG_LOG(("AuthKey Error: bad data for RSA encrypt %1").arg(Logs::mb(&tmp[0], tmp.size() * 4).str()));
+		return {}; // can't be 255-byte string
+	}
+
+	auto encBuffer = mtpBuffer();
+	encBuffer.reserve(kMaxPrimes);
+	encBuffer.resize(kSkipPrimes);
+	data.write(encBuffer);
+	encBuffer.resize(kMaxPrimes);
+	const auto bytes = bytes::make_span(encBuffer);
+
+	const auto hashSrc = bytes.subspan(
+		kSkipPrimes * sizeof(mtpPrime),
+		p_q_inner_size);
+	bytes::copy(bytes.subspan(sizeof(mtpPrime)), openssl::Sha1(hashSrc));
+	bytes::set_random(bytes.subspan(sizeInPrimes * sizeof(mtpPrime)));
+
+	const auto bytesToEncrypt = bytes.subspan(3, 256);
+	return key.encrypt(bytesToEncrypt);
+}
+
+[[nodiscard]] std::string EncryptClientDHInner(
+		const MTPClient_DH_Inner_Data &data,
+		const void *aesKey,
+		const void *aesIV) {
+	constexpr auto kSkipPrimes = openssl::kSha1Size / sizeof(mtpPrime);
+
+	auto client_dh_inner_size = tl::count_length(data);
+	auto encSize = (client_dh_inner_size >> 2) + kSkipPrimes;
+	auto encFullSize = encSize;
+	if (encSize & 0x03) {
+		encFullSize += 4 - (encSize & 0x03);
+	}
+
+	auto encBuffer = mtpBuffer();
+	encBuffer.reserve(encFullSize);
+	encBuffer.resize(kSkipPrimes);
+	data.write(encBuffer);
+	encBuffer.resize(encFullSize);
+
+	const auto bytes = bytes::make_span(encBuffer);
+
+	const auto hash = openssl::Sha1(bytes.subspan(
+		kSkipPrimes * sizeof(mtpPrime),
+		client_dh_inner_size));
+	bytes::copy(bytes, hash);
+	bytes::set_random(bytes.subspan(encSize * sizeof(mtpPrime)));
+
+	auto sdhEncString = std::string(encFullSize * 4, ' ');
+
+	aesIgeEncryptRaw(&encBuffer[0], &sdhEncString[0], encFullSize * sizeof(mtpPrime), aesKey, aesIV);
+
+	return sdhEncString;
+}
+
+// 128 lower-order bits of SHA1.
+MTPint128 NonceDigest(bytes::const_span data) {
+	const auto hash = openssl::Sha1(data);
+	return *(MTPint128*)(hash.data() + 4);
+}
+
+} // namespace
+
+DcKeyCreator::DcKeyCreator(
+	DcId dcId,
+	int16 protocolDcId,
+	not_null<AbstractConnection*> connection,
+	not_null<DcOptions*> dcOptions,
+	Delegate delegate)
+: _connection(connection)
+, _dcOptions(dcOptions)
+, _dcId(dcId)
+, _protocolDcId(protocolDcId)
+, _delegate(std::move(delegate)) {
+	Expects(_delegate.done != nullptr);
+
+	_data.nonce = openssl::RandomValue<MTPint128>();
+	pqSend();
+}
+
+DcKeyCreator::~DcKeyCreator() {
+	const auto clearBytes = [](bytes::span bytes) {
+		OPENSSL_cleanse(bytes.data(), bytes.size());
+	};
+	OPENSSL_cleanse(&_data, sizeof(_data));
+	clearBytes(_dhPrime);
+	clearBytes(_g_a);
+	clearBytes(_authKey);
+}
+
+void DcKeyCreator::pqSend() {
+	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
+		pqAnswered();
+	});
+
+	DEBUG_LOG(("AuthKey Info: sending Req_pq..."));
+	sendNotSecureRequest(MTPReq_pq_multi(_data.nonce));
+}
+
+void DcKeyCreator::pqAnswered() {
+	QObject::disconnect(
+		_connection,
+		&AbstractConnection::receivedData,
+		nullptr,
+		nullptr);
+	DEBUG_LOG(("AuthKey Info: receiving Req_pq answer..."));
+
+	MTPReq_pq::ResponseType res_pq;
+	if (!readNotSecureResponse(res_pq)) {
+		return failed();
+	}
+
+	auto &res_pq_data = res_pq.c_resPQ();
+	if (res_pq_data.vnonce() != _data.nonce) {
+		LOG(("AuthKey Error: received nonce <> sent nonce (in res_pq)!"));
+		DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&res_pq_data.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+		return failed();
+	}
+
+	const auto rsaKey = _dcOptions->getDcRSAKey(
+		_dcId,
+		res_pq.c_resPQ().vserver_public_key_fingerprints().v);
+	if (!rsaKey.valid()) {
+		return failed(Error::UnknownPublicKey);
+	}
+
+	_data.server_nonce = res_pq_data.vserver_nonce();
+	_data.new_nonce = openssl::RandomValue<MTPint256>();
+
+	const auto &pq = res_pq_data.vpq().v;
+	const auto parsed = ParsePQ(res_pq_data.vpq().v);
+	if (parsed.p.isEmpty() || parsed.q.isEmpty()) {
+		LOG(("AuthKey Error: could not factor pq!"));
+		DEBUG_LOG(("AuthKey Error: problematic pq: %1").arg(Logs::mb(pq.constData(), pq.length()).str()));
+		return failed();
+	}
+
+	auto p_q_inner = MTP_p_q_inner_data_dc(
+		res_pq_data.vpq(),
+		MTP_bytes(parsed.p),
+		MTP_bytes(parsed.q),
+		_data.nonce,
+		_data.server_nonce,
+		_data.new_nonce,
+		MTP_int(_protocolDcId));
+	const auto dhEncString = EncryptPQInnerRSA(p_q_inner, rsaKey);
+	if (dhEncString.empty()) {
+		return failed();
+	}
+
+	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
+		dhParamsAnswered();
+	});
+
+	DEBUG_LOG(("AuthKey Info: sending Req_DH_params..."));
+
+	sendNotSecureRequest(MTPReq_DH_params(
+		_data.nonce,
+		_data.server_nonce,
+		p_q_inner.c_p_q_inner_data_dc().vp(),
+		p_q_inner.c_p_q_inner_data_dc().vq(),
+		MTP_long(rsaKey.fingerprint()),
+		MTP_bytes(dhEncString)));
+}
+
+void DcKeyCreator::dhParamsAnswered() {
+	QObject::disconnect(
+		_connection,
+		&AbstractConnection::receivedData,
+		nullptr,
+		nullptr);
+	DEBUG_LOG(("AuthKey Info: receiving Req_DH_params answer..."));
+
+	MTPReq_DH_params::ResponseType res_DH_params;
+	if (!readNotSecureResponse(res_DH_params)) {
+		return failed();
+	}
+
+	switch (res_DH_params.type()) {
+	case mtpc_server_DH_params_ok: {
+		const auto &encDH(res_DH_params.c_server_DH_params_ok());
+		if (encDH.vnonce() != _data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_params_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&encDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+			return failed();
+		}
+		if (encDH.vserver_nonce() != _data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&encDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
+			return failed();
+		}
+
+		auto &encDHStr = encDH.vencrypted_answer().v;
+		uint32 encDHLen = encDHStr.length(), encDHBufLen = encDHLen >> 2;
+		if ((encDHLen & 0x03) || encDHBufLen < 6) {
+			LOG(("AuthKey Error: bad encrypted data length %1 (in server_DH_params_ok)!").arg(encDHLen));
+			DEBUG_LOG(("AuthKey Error: received encrypted data %1").arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
+			return failed();
+		}
+
+		const auto nlen = sizeof(_data.new_nonce);
+		const auto slen = sizeof(_data.server_nonce);
+		auto tmp_aes_buffer = bytes::array<1024>();
+		const auto tmp_aes = bytes::make_span(tmp_aes_buffer);
+		bytes::copy(tmp_aes, bytes::object_as_span(&_data.new_nonce));
+		bytes::copy(tmp_aes.subspan(nlen), bytes::object_as_span(&_data.server_nonce));
+		bytes::copy(tmp_aes.subspan(nlen + slen), bytes::object_as_span(&_data.new_nonce));
+		bytes::copy(tmp_aes.subspan(nlen + slen + nlen), bytes::object_as_span(&_data.new_nonce));
+		const auto sha1ns = openssl::Sha1(tmp_aes.subspan(0, nlen + slen));
+		const auto sha1sn = openssl::Sha1(tmp_aes.subspan(nlen, nlen + slen));
+		const auto sha1nn = openssl::Sha1(tmp_aes.subspan(nlen + slen, nlen + nlen));
+
+		mtpBuffer decBuffer;
+		decBuffer.resize(encDHBufLen);
+
+		const auto aesKey = bytes::make_span(_data.aesKey);
+		const auto aesIV = bytes::make_span(_data.aesIV);
+		bytes::copy(aesKey, bytes::make_span(sha1ns).subspan(0, 20));
+		bytes::copy(aesKey.subspan(20), bytes::make_span(sha1sn).subspan(0, 12));
+		bytes::copy(aesIV, bytes::make_span(sha1sn).subspan(12, 8));
+		bytes::copy(aesIV.subspan(8), bytes::make_span(sha1nn).subspan(0, 20));
+		bytes::copy(aesIV.subspan(28), bytes::object_as_span(&_data.new_nonce).subspan(0, 4));
+
+		aesIgeDecryptRaw(encDHStr.constData(), &decBuffer[0], encDHLen, aesKey.data(), aesIV.data());
+
+		const mtpPrime *from(&decBuffer[5]), *to(from), *end(from + (encDHBufLen - 5));
+		MTPServer_DH_inner_data dh_inner;
+		if (!dh_inner.read(to, end)) {
+			LOG(("AuthKey Error: could not decrypt server_DH_inner_data!"));
+			return failed();
+		}
+		const auto &dh_inner_data(dh_inner.c_server_DH_inner_data());
+		if (dh_inner_data.vnonce() != _data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_inner_data)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&dh_inner_data.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+			return failed();
+		}
+		if (dh_inner_data.vserver_nonce() != _data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_inner_data)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&dh_inner_data.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
+			return failed();
+		}
+		const auto sha1Buffer = openssl::Sha1(
+			bytes::make_span(decBuffer).subspan(
+				5 * sizeof(mtpPrime),
+				(to - from) * sizeof(mtpPrime)));
+		const auto sha1Dec = bytes::make_span(decBuffer).subspan(
+			0,
+			openssl::kSha1Size);
+		if (bytes::compare(sha1Dec, sha1Buffer)) {
+			LOG(("AuthKey Error: sha1 hash of encrypted part did not match!"));
+			DEBUG_LOG(("AuthKey Error: sha1 did not match, server_nonce: %1, new_nonce %2, encrypted data %3").arg(Logs::mb(&_data.server_nonce, 16).str()).arg(Logs::mb(&_data.new_nonce, 16).str()).arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
+			return failed();
+		}
+		base::unixtime::update(dh_inner_data.vserver_time().v);
+
+		// check that dhPrime and (dhPrime - 1) / 2 are really prime
+		if (!IsPrimeAndGood(bytes::make_span(dh_inner_data.vdh_prime().v), dh_inner_data.vg().v)) {
+			LOG(("AuthKey Error: bad dh_prime primality!"));
+			return failed();
+		}
+
+		_dhPrime = bytes::make_vector(
+			dh_inner_data.vdh_prime().v);
+		_data.g = dh_inner_data.vg().v;
+		_g_a = bytes::make_vector(dh_inner_data.vg_a().v);
+		_data.retry_id = MTP_long(0);
+		_data.retries = 0;
+	} return dhClientParamsSend();
+
+	case mtpc_server_DH_params_fail: {
+		const auto &encDH(res_DH_params.c_server_DH_params_fail());
+		if (encDH.vnonce() != _data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_params_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&encDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+			return failed();
+		}
+		if (encDH.vserver_nonce() != _data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&encDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
+			return failed();
+		}
+		if (encDH.vnew_nonce_hash() != NonceDigest(bytes::object_as_span(&_data.new_nonce))) {
+			LOG(("AuthKey Error: received new_nonce_hash did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash: %1, new_nonce: %2").arg(Logs::mb(&encDH.vnew_nonce_hash(), 16).str()).arg(Logs::mb(&_data.new_nonce, 32).str()));
+			return failed();
+		}
+		LOG(("AuthKey Error: server_DH_params_fail received!"));
+	} return failed();
+
+	}
+	LOG(("AuthKey Error: unknown server_DH_params received, typeId = %1").arg(res_DH_params.type()));
+	return failed();
+}
+
+void DcKeyCreator::dhClientParamsSend() {
+	if (++_data.retries > 5) {
+		LOG(("AuthKey Error: could not create auth_key for %1 retries").arg(_data.retries - 1));
+		return failed();
+	}
+
+	// gen rand 'b'
+	auto randomSeed = bytes::vector(ModExpFirst::kRandomPowerSize);
+	bytes::set_random(randomSeed);
+	auto g_b_data = CreateModExp(_data.g, _dhPrime, randomSeed);
+	if (g_b_data.modexp.empty()) {
+		LOG(("AuthKey Error: could not generate good g_b."));
+		return failed();
+	}
+
+	auto computedAuthKey = CreateAuthKey(_g_a, g_b_data.randomPower, _dhPrime);
+	if (computedAuthKey.empty()) {
+		LOG(("AuthKey Error: could not generate auth_key."));
+		return failed();
+	}
+	AuthKey::FillData(_authKey, computedAuthKey);
+
+	auto auth_key_sha = openssl::Sha1(_authKey);
+	memcpy(&_data.auth_key_aux_hash, auth_key_sha.data(), 8);
+	memcpy(&_data.auth_key_hash, auth_key_sha.data() + 12, 8);
+
+	const auto client_dh_inner = MTP_client_DH_inner_data(
+		_data.nonce,
+		_data.server_nonce,
+		_data.retry_id,
+		MTP_bytes(g_b_data.modexp));
+
+	auto sdhEncString = EncryptClientDHInner(
+		client_dh_inner,
+		_data.aesKey.data(),
+		_data.aesIV.data());
+
+	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
+		dhClientParamsAnswered();
+	});
+
+	DEBUG_LOG(("AuthKey Info: sending Req_client_DH_params..."));
+	sendNotSecureRequest(MTPSet_client_DH_params(
+		_data.nonce,
+		_data.server_nonce,
+		MTP_string(std::move(sdhEncString))));
+}
+
+void DcKeyCreator::dhClientParamsAnswered() {
+	QObject::disconnect(
+		_connection,
+		&AbstractConnection::receivedData,
+		nullptr,
+		nullptr);
+	DEBUG_LOG(("AuthKey Info: receiving Req_client_DH_params answer..."));
+
+	MTPSet_client_DH_params::ResponseType res_client_DH_params;
+	if (!readNotSecureResponse(res_client_DH_params)) {
+		return failed();
+	}
+
+	switch (res_client_DH_params.type()) {
+	case mtpc_dh_gen_ok: {
+		const auto &resDH(res_client_DH_params.c_dh_gen_ok());
+		if (resDH.vnonce() != _data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+			return failed();
+		}
+		if (resDH.vserver_nonce() != _data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
+			return failed();
+		}
+		_data.new_nonce_buf[32] = bytes::type(1);
+		if (resDH.vnew_nonce_hash1() != NonceDigest(_data.new_nonce_buf)) {
+			LOG(("AuthKey Error: received new_nonce_hash1 did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash1: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash1(), 16).str()).arg(Logs::mb(_data.new_nonce_buf.data(), 41).str()));
+			return failed();
+		}
+
+		uint64 salt1 = _data.new_nonce.l.l, salt2 = _data.server_nonce.l;
+		done(salt1 ^ salt2);
+	} return;
+
+	case mtpc_dh_gen_retry: {
+		const auto &resDH(res_client_DH_params.c_dh_gen_retry());
+		if (resDH.vnonce() != _data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_retry)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+			return failed();
+		}
+		if (resDH.vserver_nonce() != _data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_retry)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
+			return failed();
+		}
+		_data.new_nonce_buf[32] = bytes::type(2);
+		uchar sha1Buffer[20];
+		if (resDH.vnew_nonce_hash2() != NonceDigest(_data.new_nonce_buf)) {
+			LOG(("AuthKey Error: received new_nonce_hash2 did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash2: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash2(), 16).str()).arg(Logs::mb(_data.new_nonce_buf.data(), 41).str()));
+			return failed();
+		}
+		_data.retry_id = _data.auth_key_aux_hash;
+	} return dhClientParamsSend();
+
+	case mtpc_dh_gen_fail: {
+		const auto &resDH(res_client_DH_params.c_dh_gen_fail());
+		if (resDH.vnonce() != _data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
+			return failed();
+		}
+		if (resDH.vserver_nonce() != _data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
+			return failed();
+		}
+		_data.new_nonce_buf[32] = bytes::type(3);
+		uchar sha1Buffer[20];
+		if (resDH.vnew_nonce_hash3() != NonceDigest(_data.new_nonce_buf)) {
+			LOG(("AuthKey Error: received new_nonce_hash3 did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash3: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash3(), 16).str()).arg(Logs::mb(_data.new_nonce_buf.data(), 41).str()));
+			return failed();
+		}
+		LOG(("AuthKey Error: dh_gen_fail received!"));
+	} return failed();
+	}
+
+	LOG(("AuthKey Error: unknown set_client_DH_params_answer received, typeId = %1").arg(res_client_DH_params.type()));
+	return failed();
+}
+
+template <typename Request>
+void DcKeyCreator::sendNotSecureRequest(const Request &request) {
+	auto packet = _connection->prepareNotSecurePacket(
+		request,
+		base::unixtime::mtproto_msg_id());
+
+	DEBUG_LOG(("AuthKey Info: sending request, size: %1, time: %3"
+		).arg(packet.size() - 8
+		).arg(packet[5]));
+
+	const auto bytesSize = packet.size() * sizeof(mtpPrime);
+
+	_connection->sendData(std::move(packet));
+
+	if (_delegate.sentSome) {
+		_delegate.sentSome(bytesSize);
+	}
+}
+
+template <typename Response>
+bool DcKeyCreator::readNotSecureResponse(Response &response) {
+	if (_delegate.receivedSome) {
+		_delegate.receivedSome();
+	}
+
+	if (_connection->received().empty()) {
+		LOG(("AuthKey Error: "
+			"trying to read response from empty received list"));
+		return false;
+	}
+
+	const auto buffer = std::move(_connection->received().front());
+	_connection->received().pop_front();
+
+	const auto answer = _connection->parseNotSecureResponse(buffer);
+	if (answer.empty()) {
+		return false;
+	}
+	auto from = answer.data();
+	return response.read(from, from + answer.size());
+}
+
+void DcKeyCreator::failed(Error error) {
+	auto onstack = std::move(_delegate.done);
+	onstack(tl::unexpected(error));
+}
+
+void DcKeyCreator::done(uint64 serverSalt) {
+	auto result = Result();
+	result.key = std::make_shared<AuthKey>(
+		AuthKey::Type::Generated,
+		_dcId,
+		_authKey);
+	result.serverSalt = serverSalt;
+	auto onstack = std::move(_delegate.done);
+	onstack(std::move(result));
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
new file mode 100644
index 000000000..6d774143b
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -0,0 +1,102 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "mtproto/core_types.h"
+#include "mtproto/auth_key.h"
+#include "mtproto/connection_abstract.h"
+#include "base/basic_types.h"
+#include "base/expected.h"
+
+namespace MTP {
+class DcOptions;
+} // namespace MTP
+
+namespace MTP::details {
+
+using namespace ::MTP::internal;
+
+class DcKeyCreator final {
+public:
+	enum class Error {
+		UnknownPublicKey,
+		Other,
+	};
+	struct Result {
+		AuthKeyPtr key;
+		uint64 serverSalt = 0;
+	};
+	struct Delegate {
+		FnMut<void(base::expected<Result, Error>)> done;
+		Fn<void(uint64)> sentSome;
+		Fn<void()> receivedSome;
+	};
+
+	DcKeyCreator(
+		DcId dcId,
+		int16 protocolDcId,
+		not_null<AbstractConnection*> connection,
+		not_null<DcOptions*> dcOptions,
+		Delegate delegate);
+	~DcKeyCreator();
+
+private:
+	// Auth key creation fields and methods
+	struct Data {
+		Data()
+		: new_nonce(*(MTPint256*)((uchar*)new_nonce_buf.data()))
+		, auth_key_aux_hash(*(MTPlong*)((uchar*)new_nonce_buf.data() + 33)) {
+		}
+		MTPint128 nonce, server_nonce;
+
+		// 32 bytes new_nonce + 1 check byte + 8 bytes of auth_key_aux_hash.
+		bytes::array<41> new_nonce_buf;
+
+		MTPint256 &new_nonce;
+		MTPlong &auth_key_aux_hash;
+
+		uint32 retries = 0;
+		MTPlong retry_id;
+
+		int32 g = 0;
+
+		bytes::array<32> aesKey;
+		bytes::array<32> aesIV;
+		MTPlong auth_key_hash;
+	};
+
+	template <typename Request>
+	void sendNotSecureRequest(const Request &request);
+
+	template <typename Response>
+	[[nodiscard]] bool readNotSecureResponse(Response &response);
+
+	void pqSend();
+	void pqAnswered();
+	void dhParamsAnswered();
+	void dhClientParamsSend();
+	void dhClientParamsAnswered();
+
+	void failed(Error error = Error::Other);
+	void done(uint64 serverSalt);
+
+	const not_null<AbstractConnection*> _connection;
+	const not_null<DcOptions*> _dcOptions;
+	const DcId _dcId;
+	const int16 _protocolDcId = 0;
+	Delegate _delegate;
+
+	Data _data;
+	bytes::vector _dhPrime;
+	bytes::vector _g_a;
+	AuthKey::Data _authKey = { { gsl::byte{} } };
+	FnMut<void(base::expected<Result, Error>)> _done;
+
+};
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 14ea8fae7..64881911e 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/mtp_instance.h"
 
+#include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/session.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/dcenter.h"
@@ -74,7 +75,6 @@ public:
 	void cancel(mtpRequestId requestId);
 	[[nodiscard]] int32 state(mtpRequestId requestId); // < 0 means waiting for such count of ms
 	void killSession(ShiftedDcId shiftedDcId);
-	void killSession(std::unique_ptr<internal::Session> session);
 	void stopSession(ShiftedDcId shiftedDcId);
 	void reInitConnection(DcId dcId);
 	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
@@ -133,6 +133,7 @@ public:
 	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
 	void performKeyDestroy(ShiftedDcId shiftedDcId);
 	void completedKeyDestroy(ShiftedDcId shiftedDcId);
+	void checkMainDcKey();
 
 	void clearKilledSessions();
 	void prepareToDestroy();
@@ -227,6 +228,8 @@ private:
 
 	base::Timer _checkDelayedTimer;
 
+	std::unique_ptr<details::DcKeyChecker> _mainDcKeyChecker;
+
 	// Debug flag to find out how we end up crashing.
 	bool MustNotCreateSessions = false;
 
@@ -1102,13 +1105,13 @@ void Instance::Private::globalCallback(const mtpPrime *from, const mtpPrime *end
 	[[maybe_unused]] bool result = (*_globalHandler.onDone)(0, from, end);
 }
 
-void Instance::Private::onStateChange(int32 dcWithShift, int32 state) {
+void Instance::Private::onStateChange(ShiftedDcId dcWithShift, int32 state) {
 	if (_stateChangedHandler) {
 		_stateChangedHandler(dcWithShift, state);
 	}
 }
 
-void Instance::Private::onSessionReset(int32 dcWithShift) {
+void Instance::Private::onSessionReset(ShiftedDcId dcWithShift) {
 	if (_sessionResetHandler) {
 		_sessionResetHandler(dcWithShift);
 	}
@@ -1505,6 +1508,26 @@ void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 	}
 }
 
+void Instance::Private::checkMainDcKey() {
+	if (_mainDcKeyChecker) {
+		return;
+	}
+	const auto id = mainDcId();
+	const auto key = [&] {
+		QReadLocker lock(&_keysForWriteLock);
+		const auto i = _keysForWrite.find(id);
+		return (i != end(_keysForWrite)) ? i->second : AuthKeyPtr();
+	}();
+	if (!key) {
+		return;
+	}
+	_mainDcKeyChecker = std::make_unique<details::DcKeyChecker>(
+		_instance,
+		id,
+		key,
+		[=] { _mainDcKeyChecker = nullptr; });
+}
+
 void Instance::Private::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
 	_globalHandler.onDone = onDone;
 }
@@ -1751,6 +1774,10 @@ void Instance::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
 			LOG(("MTP Info: checkIfKeyWasDestroyed on destroying key %1, "
 				"assuming it is destroyed.").arg(shiftedDcId));
 			_private->completedKeyDestroy(shiftedDcId);
+		} else if (BareDcId(shiftedDcId) == mainDcId()) {
+			LOG(("MTP Info: checkIfKeyWasDestroyed for main dc %1, "
+				"checking.").arg(shiftedDcId));
+			_private->checkMainDcKey();
 		}
 	});
 }
diff --git a/Telegram/SourceFiles/mtproto/mtproto_dh_utils.cpp b/Telegram/SourceFiles/mtproto/mtproto_dh_utils.cpp
new file mode 100644
index 000000000..9c136eb1d
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/mtproto_dh_utils.cpp
@@ -0,0 +1,173 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/mtproto_dh_utils.h"
+
+namespace MTP {
+namespace {
+
+constexpr auto kMaxModExpSize = 256;
+
+bool IsPrimeAndGoodCheck(const openssl::BigNum &prime, int g) {
+	constexpr auto kGoodPrimeBitsCount = 2048;
+
+	if (prime.failed()
+		|| prime.isNegative()
+		|| prime.bitsSize() != kGoodPrimeBitsCount) {
+		LOG(("MTP Error: Bad prime bits count %1, expected %2."
+			).arg(prime.bitsSize()
+			).arg(kGoodPrimeBitsCount));
+		return false;
+	}
+
+	const auto context = openssl::Context();
+	if (!prime.isPrime(context)) {
+		LOG(("MTP Error: Bad prime."));
+		return false;
+	}
+
+	switch (g) {
+	case 2: {
+		const auto mod8 = prime.countModWord(8);
+		if (mod8 != 7) {
+			LOG(("BigNum PT Error: bad g value: %1, mod8: %2").arg(g).arg(mod8));
+			return false;
+		}
+	} break;
+	case 3: {
+		const auto mod3 = prime.countModWord(3);
+		if (mod3 != 2) {
+			LOG(("BigNum PT Error: bad g value: %1, mod3: %2").arg(g).arg(mod3));
+			return false;
+		}
+	} break;
+	case 4: break;
+	case 5: {
+		const auto mod5 = prime.countModWord(5);
+		if (mod5 != 1 && mod5 != 4) {
+			LOG(("BigNum PT Error: bad g value: %1, mod5: %2").arg(g).arg(mod5));
+			return false;
+		}
+	} break;
+	case 6: {
+		const auto mod24 = prime.countModWord(24);
+		if (mod24 != 19 && mod24 != 23) {
+			LOG(("BigNum PT Error: bad g value: %1, mod24: %2").arg(g).arg(mod24));
+			return false;
+		}
+	} break;
+	case 7: {
+		const auto mod7 = prime.countModWord(7);
+		if (mod7 != 3 && mod7 != 5 && mod7 != 6) {
+			LOG(("BigNum PT Error: bad g value: %1, mod7: %2").arg(g).arg(mod7));
+			return false;
+		}
+	} break;
+	default: {
+		LOG(("BigNum PT Error: bad g value: %1").arg(g));
+		return false;
+	} break;
+	}
+
+	if (!openssl::BigNum(prime).subWord(1).divWord(2).isPrime(context)) {
+		LOG(("MTP Error: Bad (prime - 1) / 2."));
+		return false;
+	}
+
+	return true;
+}
+
+} // namespace
+
+bool IsGoodModExpFirst(
+		const openssl::BigNum &modexp,
+		const openssl::BigNum &prime) {
+	const auto diff = openssl::BigNum::Sub(prime, modexp);
+	if (modexp.failed() || prime.failed() || diff.failed()) {
+		return false;
+	}
+	constexpr auto kMinDiffBitsCount = 2048 - 64;
+	if (diff.isNegative()
+		|| diff.bitsSize() < kMinDiffBitsCount
+		|| modexp.bitsSize() < kMinDiffBitsCount
+		|| modexp.bytesSize() > kMaxModExpSize) {
+		return false;
+	}
+	return true;
+}
+
+bool IsPrimeAndGood(bytes::const_span primeBytes, int g) {
+	static constexpr unsigned char GoodPrime[] = {
+		0xC7, 0x1C, 0xAE, 0xB9, 0xC6, 0xB1, 0xC9, 0x04, 0x8E, 0x6C, 0x52, 0x2F, 0x70, 0xF1, 0x3F, 0x73,
+		0x98, 0x0D, 0x40, 0x23, 0x8E, 0x3E, 0x21, 0xC1, 0x49, 0x34, 0xD0, 0x37, 0x56, 0x3D, 0x93, 0x0F,
+		0x48, 0x19, 0x8A, 0x0A, 0xA7, 0xC1, 0x40, 0x58, 0x22, 0x94, 0x93, 0xD2, 0x25, 0x30, 0xF4, 0xDB,
+		0xFA, 0x33, 0x6F, 0x6E, 0x0A, 0xC9, 0x25, 0x13, 0x95, 0x43, 0xAE, 0xD4, 0x4C, 0xCE, 0x7C, 0x37,
+		0x20, 0xFD, 0x51, 0xF6, 0x94, 0x58, 0x70, 0x5A, 0xC6, 0x8C, 0xD4, 0xFE, 0x6B, 0x6B, 0x13, 0xAB,
+		0xDC, 0x97, 0x46, 0x51, 0x29, 0x69, 0x32, 0x84, 0x54, 0xF1, 0x8F, 0xAF, 0x8C, 0x59, 0x5F, 0x64,
+		0x24, 0x77, 0xFE, 0x96, 0xBB, 0x2A, 0x94, 0x1D, 0x5B, 0xCD, 0x1D, 0x4A, 0xC8, 0xCC, 0x49, 0x88,
+		0x07, 0x08, 0xFA, 0x9B, 0x37, 0x8E, 0x3C, 0x4F, 0x3A, 0x90, 0x60, 0xBE, 0xE6, 0x7C, 0xF9, 0xA4,
+		0xA4, 0xA6, 0x95, 0x81, 0x10, 0x51, 0x90, 0x7E, 0x16, 0x27, 0x53, 0xB5, 0x6B, 0x0F, 0x6B, 0x41,
+		0x0D, 0xBA, 0x74, 0xD8, 0xA8, 0x4B, 0x2A, 0x14, 0xB3, 0x14, 0x4E, 0x0E, 0xF1, 0x28, 0x47, 0x54,
+		0xFD, 0x17, 0xED, 0x95, 0x0D, 0x59, 0x65, 0xB4, 0xB9, 0xDD, 0x46, 0x58, 0x2D, 0xB1, 0x17, 0x8D,
+		0x16, 0x9C, 0x6B, 0xC4, 0x65, 0xB0, 0xD6, 0xFF, 0x9C, 0xA3, 0x92, 0x8F, 0xEF, 0x5B, 0x9A, 0xE4,
+		0xE4, 0x18, 0xFC, 0x15, 0xE8, 0x3E, 0xBE, 0xA0, 0xF8, 0x7F, 0xA9, 0xFF, 0x5E, 0xED, 0x70, 0x05,
+		0x0D, 0xED, 0x28, 0x49, 0xF4, 0x7B, 0xF9, 0x59, 0xD9, 0x56, 0x85, 0x0C, 0xE9, 0x29, 0x85, 0x1F,
+		0x0D, 0x81, 0x15, 0xF6, 0x35, 0xB1, 0x05, 0xEE, 0x2E, 0x4E, 0x15, 0xD0, 0x4B, 0x24, 0x54, 0xBF,
+		0x6F, 0x4F, 0xAD, 0xF0, 0x34, 0xB1, 0x04, 0x03, 0x11, 0x9C, 0xD8, 0xE3, 0xB9, 0x2F, 0xCC, 0x5B };
+
+	if (!bytes::compare(bytes::make_span(GoodPrime), primeBytes)) {
+		if (g == 3 || g == 4 || g == 5 || g == 7) {
+			return true;
+		}
+	}
+
+	return IsPrimeAndGoodCheck(openssl::BigNum(primeBytes), g);
+}
+
+ModExpFirst CreateModExp(
+		int g,
+		bytes::const_span primeBytes,
+		bytes::const_span randomSeed) {
+	Expects(randomSeed.size() == ModExpFirst::kRandomPowerSize);
+
+	using namespace openssl;
+
+	BigNum prime(primeBytes);
+	auto result = ModExpFirst();
+	result.randomPower.resize(ModExpFirst::kRandomPowerSize);
+	while (true) {
+		bytes::set_random(result.randomPower);
+		for (auto i = 0; i != ModExpFirst::kRandomPowerSize; ++i) {
+			result.randomPower[i] ^= randomSeed[i];
+		}
+		const auto modexp = BigNum::ModExp(
+			BigNum(g),
+			BigNum(result.randomPower),
+			prime);
+		if (IsGoodModExpFirst(modexp, prime)) {
+			result.modexp = modexp.getBytes();
+			return result;
+		}
+	}
+}
+
+bytes::vector CreateAuthKey(
+		bytes::const_span firstBytes,
+		bytes::const_span randomBytes,
+		bytes::const_span primeBytes) {
+	using openssl::BigNum;
+
+	const auto first = BigNum(firstBytes);
+	const auto prime = BigNum(primeBytes);
+	if (!IsGoodModExpFirst(first, prime)) {
+		LOG(("AuthKey Error: Bad first prime in CreateAuthKey()."));
+		return {};
+	}
+	return BigNum::ModExp(first, BigNum(randomBytes), prime).getBytes();
+}
+
+} // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/mtproto_dh_utils.h b/Telegram/SourceFiles/mtproto/mtproto_dh_utils.h
new file mode 100644
index 000000000..2860bf02c
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/mtproto_dh_utils.h
@@ -0,0 +1,35 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/bytes.h"
+#include "base/openssl_help.h"
+
+namespace MTP {
+
+struct ModExpFirst {
+	static constexpr auto kRandomPowerSize = 256;
+
+	bytes::vector modexp;
+	bytes::vector randomPower;
+};
+
+[[nodiscard]] bool IsPrimeAndGood(bytes::const_span primeBytes, int g);
+[[nodiscard]] bool IsGoodModExpFirst(
+	const openssl::BigNum &modexp,
+	const openssl::BigNum &prime);
+[[nodiscard]] ModExpFirst CreateModExp(
+	int g,
+	bytes::const_span primeBytes,
+	bytes::const_span randomSeed);
+[[nodiscard]] bytes::vector CreateAuthKey(
+	bytes::const_span firstBytes,
+	bytes::const_span randomBytes,
+	bytes::const_span primeBytes);
+
+} // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/mtproto_proxy_data.cpp b/Telegram/SourceFiles/mtproto/mtproto_proxy_data.cpp
new file mode 100644
index 000000000..cb401a589
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/mtproto_proxy_data.cpp
@@ -0,0 +1,238 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/mtproto_proxy_data.h"
+
+#include "base/qthelp_url.h"
+
+namespace MTP {
+namespace {
+
+[[nodiscard]] bool IsHexMtprotoPassword(const QString &password) {
+	const auto size = password.size();
+	if (size < 32 || size % 2 == 1) {
+		return false;
+	}
+	const auto bad = [](QChar ch) {
+		const auto code = ch.unicode();
+		return (code < 'a' || code > 'f')
+			&& (code < 'A' || code > 'F')
+			&& (code < '0' || code > '9');
+	};
+	const auto i = std::find_if(password.begin(), password.end(), bad);
+	return (i == password.end());
+}
+
+[[nodiscard]] ProxyData::Status HexMtprotoPasswordStatus(
+		const QString &password) {
+	const auto size = password.size() / 2;
+	const auto valid = (size == 16)
+		|| (size == 17 && (password[0] == 'd') && (password[1] == 'd'))
+		|| (size >= 21 && (password[0] == 'e') && (password[1] == 'e'));
+	if (valid) {
+		return ProxyData::Status::Valid;
+	} else if (size < 16) {
+		return ProxyData::Status::Invalid;
+	}
+	return ProxyData::Status::Unsupported;
+}
+
+[[nodiscard]] bytes::vector SecretFromHexMtprotoPassword(
+		const QString &password) {
+	Expects(password.size() % 2 == 0);
+
+	const auto size = password.size() / 2;
+	const auto fromHex = [](QChar ch) -> int {
+		const auto code = int(ch.unicode());
+		if (code >= '0' && code <= '9') {
+			return (code - '0');
+		} else if (code >= 'A' && code <= 'F') {
+			return 10 + (code - 'A');
+		} else if (ch >= 'a' && ch <= 'f') {
+			return 10 + (code - 'a');
+		}
+		Unexpected("Code in ProxyData fromHex.");
+	};
+	auto result = bytes::vector(size);
+	for (auto i = 0; i != size; ++i) {
+		const auto high = fromHex(password[2 * i]);
+		const auto low = fromHex(password[2 * i + 1]);
+		if (high < 0 || low < 0) {
+			return {};
+		}
+		result[i] = static_cast<bytes::type>(high * 16 + low);
+	}
+	return result;
+}
+
+[[nodiscard]] QStringRef Base64UrlInner(const QString &password) {
+	Expects(password.size() > 2);
+
+	// Skip one or two '=' at the end of the string.
+	return password.midRef(0, [&] {
+		auto result = password.size();
+		for (auto i = 0; i != 2; ++i) {
+			const auto prev = result - 1;
+			if (password[prev] != '=') {
+				break;
+			}
+			result = prev;
+		}
+		return result;
+	}());
+}
+
+[[nodiscard]] bool IsBase64UrlMtprotoPassword(const QString &password) {
+	const auto size = password.size();
+	if (size < 22 || size % 4 == 1) {
+		return false;
+	}
+	const auto bad = [](QChar ch) {
+		const auto code = ch.unicode();
+		return (code < 'a' || code > 'z')
+			&& (code < 'A' || code > 'Z')
+			&& (code < '0' || code > '9')
+			&& (code != '_')
+			&& (code != '-');
+	};
+	const auto inner = Base64UrlInner(password);
+	const auto begin = inner.data();
+	const auto end = begin + inner.size();
+	return (std::find_if(begin, end, bad) == end);
+}
+
+[[nodiscard]] ProxyData::Status Base64UrlMtprotoPasswordStatus(
+		const QString &password) {
+	const auto inner = Base64UrlInner(password);
+	const auto size = (inner.size() * 3) / 4;
+	const auto valid = (size == 16)
+		|| (size == 17
+			&& (password[0] == '3')
+			&& ((password[1] >= 'Q' && password[1] <= 'Z')
+				|| (password[1] >= 'a' && password[1] <= 'f')))
+		|| (size >= 21
+			&& (password[0] == '7')
+			&& (password[1] >= 'g')
+			&& (password[1] <= 'v'));
+	if (size < 16) {
+		return ProxyData::Status::Invalid;
+	} else if (valid) {
+		return ProxyData::Status::Valid;
+	}
+	return ProxyData::Status::Unsupported;
+}
+
+[[nodiscard]] bytes::vector SecretFromBase64UrlMtprotoPassword(
+		const QString &password) {
+	const auto result = QByteArray::fromBase64(
+		password.toLatin1(),
+		QByteArray::Base64UrlEncoding);
+	return bytes::make_vector(bytes::make_span(result));
+}
+
+} // namespace
+
+bool ProxyData::valid() const {
+	return status() == Status::Valid;
+}
+
+ProxyData::Status ProxyData::status() const {
+	if (type == Type::None || host.isEmpty() || !port) {
+		return Status::Invalid;
+	} else if (type == Type::Mtproto) {
+		return MtprotoPasswordStatus(password);
+	}
+	return Status::Valid;
+}
+
+bool ProxyData::supportsCalls() const {
+	return (type == Type::Socks5);
+}
+
+bool ProxyData::tryCustomResolve() const {
+	return (type == Type::Socks5 || type == Type::Mtproto)
+		&& !qthelp::is_ipv6(host)
+		&& !QRegularExpression(
+			QStringLiteral("^\\d+\\.\\d+\\.\\d+\\.\\d+$")
+		).match(host).hasMatch();
+}
+
+bytes::vector ProxyData::secretFromMtprotoPassword() const {
+	Expects(type == Type::Mtproto);
+
+	if (IsHexMtprotoPassword(password)) {
+		return SecretFromHexMtprotoPassword(password);
+	} else if (IsBase64UrlMtprotoPassword(password)) {
+		return SecretFromBase64UrlMtprotoPassword(password);
+	}
+	return {};
+}
+
+ProxyData::operator bool() const {
+	return valid();
+}
+
+bool ProxyData::operator==(const ProxyData &other) const {
+	if (!valid()) {
+		return !other.valid();
+	}
+	return (type == other.type)
+		&& (host == other.host)
+		&& (port == other.port)
+		&& (user == other.user)
+		&& (password == other.password);
+}
+
+bool ProxyData::operator!=(const ProxyData &other) const {
+	return !(*this == other);
+}
+
+bool ProxyData::ValidMtprotoPassword(const QString &password) {
+	return MtprotoPasswordStatus(password) == Status::Valid;
+}
+
+ProxyData::Status ProxyData::MtprotoPasswordStatus(const QString &password) {
+	if (IsHexMtprotoPassword(password)) {
+		return HexMtprotoPasswordStatus(password);
+	} else if (IsBase64UrlMtprotoPassword(password)) {
+		return Base64UrlMtprotoPasswordStatus(password);
+	}
+	return Status::Invalid;
+}
+
+ProxyData ToDirectIpProxy(const ProxyData &proxy, int ipIndex) {
+	if (!proxy.tryCustomResolve()
+		|| ipIndex < 0
+		|| ipIndex >= proxy.resolvedIPs.size()) {
+		return proxy;
+	}
+	return {
+		proxy.type,
+		proxy.resolvedIPs[ipIndex],
+		proxy.port,
+		proxy.user,
+		proxy.password
+	};
+}
+
+QNetworkProxy ToNetworkProxy(const ProxyData &proxy) {
+	if (proxy.type == ProxyData::Type::None) {
+		return QNetworkProxy::DefaultProxy;
+	} else if (proxy.type == ProxyData::Type::Mtproto) {
+		return QNetworkProxy::NoProxy;
+	}
+	return QNetworkProxy(
+		(proxy.type == ProxyData::Type::Socks5
+			? QNetworkProxy::Socks5Proxy
+			: QNetworkProxy::HttpProxy),
+		proxy.host,
+		proxy.port,
+		proxy.user,
+		proxy.password);
+}
+
+} // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/mtproto_proxy_data.h b/Telegram/SourceFiles/mtproto/mtproto_proxy_data.h
new file mode 100644
index 000000000..52acf6661
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/mtproto_proxy_data.h
@@ -0,0 +1,58 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+namespace MTP {
+
+struct ProxyData {
+	enum class Settings {
+		System,
+		Enabled,
+		Disabled,
+	};
+	enum class Type {
+		None,
+		Socks5,
+		Http,
+		Mtproto,
+	};
+	enum class Status {
+		Valid,
+		Unsupported,
+		Invalid,
+	};
+
+	Type type = Type::None;
+	QString host;
+	uint32 port = 0;
+	QString user, password;
+
+	std::vector<QString> resolvedIPs;
+	crl::time resolvedExpireAt = 0;
+
+	[[nodiscard]] bool valid() const;
+	[[nodiscard]] Status status() const;
+	[[nodiscard]] bool supportsCalls() const;
+	[[nodiscard]] bool tryCustomResolve() const;
+	[[nodiscard]] bytes::vector secretFromMtprotoPassword() const;
+	[[nodiscard]] explicit operator bool() const;
+	[[nodiscard]] bool operator==(const ProxyData &other) const;
+	[[nodiscard]] bool operator!=(const ProxyData &other) const;
+
+	[[nodiscard]] static bool ValidMtprotoPassword(const QString &password);
+	[[nodiscard]] static Status MtprotoPasswordStatus(
+		const QString &password);
+
+};
+
+[[nodiscard]] ProxyData ToDirectIpProxy(
+	const ProxyData &proxy,
+	int ipIndex = 0);
+[[nodiscard]] QNetworkProxy ToNetworkProxy(const ProxyData &proxy);
+
+} // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/rsa_public_key.cpp b/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
index 3188fb65f..361c9930d 100644
--- a/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
+++ b/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
@@ -92,133 +92,159 @@ RSA *CreateRaw(bytes::const_span key) {
 
 class RSAPublicKey::Private {
 public:
-	Private(bytes::const_span key)
-	: _rsa(CreateRaw(key)) {
-		if (_rsa) {
-			computeFingerprint();
-		}
-	}
-	Private(bytes::const_span nBytes, bytes::const_span eBytes)
-	: _rsa(RSA_new()) {
-		if (_rsa) {
-			const auto n = openssl::BigNum(nBytes).takeRaw();
-			const auto e = openssl::BigNum(eBytes).takeRaw();
-			const auto valid = (n != nullptr) && (e != nullptr);
-			// We still pass both values to RSA_set0_key() so that even
-			// if only one of them is valid RSA would take ownership of it.
-			if (!RSA_set0_key(_rsa, n, e, nullptr) || !valid) {
-				RSA_free(base::take(_rsa));
-			} else {
-				computeFingerprint();
-			}
-		}
-	}
-	bytes::vector getN() const {
-		Expects(isValid());
+	explicit Private(bytes::const_span key);
+	Private(bytes::const_span nBytes, bytes::const_span eBytes);
+	~Private();
 
-		const BIGNUM *n;
-		RSA_get0_key(_rsa, &n, nullptr, nullptr);
-		return toBytes(n);
-	}
-	bytes::vector getE() const {
-		Expects(isValid());
-
-		const BIGNUM *e;
-		RSA_get0_key(_rsa, nullptr, &e, nullptr);
-		return toBytes(e);
-	}
-	uint64 getFingerPrint() const {
-		return _fingerprint;
-	}
-	bool isValid() const {
-		return _rsa != nullptr;
-	}
-	bytes::vector encrypt(bytes::const_span data) const {
-		Expects(isValid());
-
-		constexpr auto kEncryptSize = 256;
-		auto result = bytes::vector(kEncryptSize, gsl::byte {});
-		auto res = RSA_public_encrypt(kEncryptSize, reinterpret_cast<const unsigned char*>(data.data()), reinterpret_cast<unsigned char*>(result.data()), _rsa, RSA_NO_PADDING);
-		if (res < 0 || res > kEncryptSize) {
-			ERR_load_crypto_strings();
-			LOG(("RSA Error: RSA_public_encrypt failed, key fp: %1, result: %2, error: %3").arg(getFingerPrint()).arg(res).arg(ERR_error_string(ERR_get_error(), 0)));
-			return {};
-		} else if (auto zeroBytes = kEncryptSize - res) {
-			auto resultBytes = gsl::make_span(result);
-			bytes::move(resultBytes.subspan(zeroBytes, res), resultBytes.subspan(0, res));
-			bytes::set_with_const(resultBytes.subspan(0, zeroBytes), gsl::byte {});
-		}
-		return result;
-	}
-	bytes::vector decrypt(bytes::const_span data) const {
-		Expects(isValid());
-
-		constexpr auto kDecryptSize = 256;
-		auto result = bytes::vector(kDecryptSize, gsl::byte {});
-		auto res = RSA_public_decrypt(kDecryptSize, reinterpret_cast<const unsigned char*>(data.data()), reinterpret_cast<unsigned char*>(result.data()), _rsa, RSA_NO_PADDING);
-		if (res < 0 || res > kDecryptSize) {
-			ERR_load_crypto_strings();
-			LOG(("RSA Error: RSA_public_encrypt failed, key fp: %1, result: %2, error: %3").arg(getFingerPrint()).arg(res).arg(ERR_error_string(ERR_get_error(), 0)));
-			return {};
-		} else if (auto zeroBytes = kDecryptSize - res) {
-			auto resultBytes = gsl::make_span(result);
-			bytes::move(resultBytes.subspan(zeroBytes - res, res), resultBytes.subspan(0, res));
-			bytes::set_with_const(resultBytes.subspan(0, zeroBytes - res), gsl::byte {});
-		}
-		return result;
-	}
-	bytes::vector encryptOAEPpadding(bytes::const_span data) const {
-		Expects(isValid());
-
-		const auto resultSize = RSA_size(_rsa);
-		auto result = bytes::vector(resultSize, gsl::byte{});
-		const auto encryptedSize = RSA_public_encrypt(
-			data.size(),
-			reinterpret_cast<const unsigned char*>(data.data()),
-			reinterpret_cast<unsigned char*>(result.data()),
-			_rsa,
-			RSA_PKCS1_OAEP_PADDING);
-		if (encryptedSize != resultSize) {
-			ERR_load_crypto_strings();
-			LOG(("RSA Error: RSA_public_encrypt failed, "
-				"key fp: %1, result: %2, error: %3"
-				).arg(getFingerPrint()
-				).arg(encryptedSize
-				).arg(ERR_error_string(ERR_get_error(), 0)
-				));
-			return {};
-		}
-		return result;
-	}
-	~Private() {
-		RSA_free(_rsa);
-	}
+	[[nodiscard]] bool valid() const;
+	[[nodiscard]] uint64 fingerprint() const;
+	[[nodiscard]] bytes::vector getN() const;
+	[[nodiscard]] bytes::vector getE() const;
+	[[nodiscard]] bytes::vector encrypt(bytes::const_span data) const;
+	[[nodiscard]] bytes::vector decrypt(bytes::const_span data) const;
+	[[nodiscard]] bytes::vector encryptOAEPpadding(
+		bytes::const_span data) const;
 
 private:
-	void computeFingerprint() {
-		Expects(isValid());
-
-		const BIGNUM *n, *e;
-		mtpBuffer string;
-		RSA_get0_key(_rsa, &n, &e, nullptr);
-		MTP_bytes(toBytes(n)).write(string);
-		MTP_bytes(toBytes(e)).write(string);
-
-		uchar sha1Buffer[20];
-		_fingerprint = *(uint64*)(hashSha1(&string[0], string.size() * sizeof(mtpPrime), sha1Buffer) + 3);
-	}
-	static bytes::vector toBytes(const BIGNUM *number) {
-		auto size = BN_num_bytes(number);
-		auto result = bytes::vector(size, gsl::byte {});
-		BN_bn2bin(number, reinterpret_cast<unsigned char*>(result.data()));
-		return result;
-	}
+	void computeFingerprint();
+	[[nodiscard]] static bytes::vector ToBytes(const BIGNUM *number);
 
 	RSA *_rsa = nullptr;
 	uint64 _fingerprint = 0;
 
 };
 
+RSAPublicKey::Private::Private(bytes::const_span key)
+	: _rsa(CreateRaw(key)) {
+	if (_rsa) {
+		computeFingerprint();
+	}
+}
+
+RSAPublicKey::Private::Private(bytes::const_span nBytes, bytes::const_span eBytes)
+	: _rsa(RSA_new()) {
+	if (_rsa) {
+		const auto n = openssl::BigNum(nBytes).takeRaw();
+		const auto e = openssl::BigNum(eBytes).takeRaw();
+		const auto valid = (n != nullptr) && (e != nullptr);
+		// We still pass both values to RSA_set0_key() so that even
+		// if only one of them is valid RSA would take ownership of it.
+		if (!RSA_set0_key(_rsa, n, e, nullptr) || !valid) {
+			RSA_free(base::take(_rsa));
+		} else {
+			computeFingerprint();
+		}
+	}
+}
+
+bool RSAPublicKey::Private::valid() const {
+	return _rsa != nullptr;
+}
+
+uint64 RSAPublicKey::Private::fingerprint() const {
+	return _fingerprint;
+}
+
+bytes::vector RSAPublicKey::Private::getN() const {
+	Expects(valid());
+
+	const BIGNUM *n;
+	RSA_get0_key(_rsa, &n, nullptr, nullptr);
+	return ToBytes(n);
+}
+
+bytes::vector RSAPublicKey::Private::getE() const {
+	Expects(valid());
+
+	const BIGNUM *e;
+	RSA_get0_key(_rsa, nullptr, &e, nullptr);
+	return ToBytes(e);
+}
+
+bytes::vector RSAPublicKey::Private::encrypt(bytes::const_span data) const {
+	Expects(valid());
+
+	constexpr auto kEncryptSize = 256;
+	auto result = bytes::vector(kEncryptSize, gsl::byte{});
+	auto res = RSA_public_encrypt(kEncryptSize, reinterpret_cast<const unsigned char*>(data.data()), reinterpret_cast<unsigned char*>(result.data()), _rsa, RSA_NO_PADDING);
+	if (res < 0 || res > kEncryptSize) {
+		ERR_load_crypto_strings();
+		LOG(("RSA Error: RSA_public_encrypt failed, key fp: %1, result: %2, error: %3").arg(fingerprint()).arg(res).arg(ERR_error_string(ERR_get_error(), 0)));
+		return {};
+	} else if (auto zeroBytes = kEncryptSize - res) {
+		auto resultBytes = gsl::make_span(result);
+		bytes::move(resultBytes.subspan(zeroBytes, res), resultBytes.subspan(0, res));
+		bytes::set_with_const(resultBytes.subspan(0, zeroBytes), gsl::byte{});
+	}
+	return result;
+}
+
+bytes::vector RSAPublicKey::Private::decrypt(bytes::const_span data) const {
+	Expects(valid());
+
+	constexpr auto kDecryptSize = 256;
+	auto result = bytes::vector(kDecryptSize, gsl::byte{});
+	auto res = RSA_public_decrypt(kDecryptSize, reinterpret_cast<const unsigned char*>(data.data()), reinterpret_cast<unsigned char*>(result.data()), _rsa, RSA_NO_PADDING);
+	if (res < 0 || res > kDecryptSize) {
+		ERR_load_crypto_strings();
+		LOG(("RSA Error: RSA_public_encrypt failed, key fp: %1, result: %2, error: %3").arg(fingerprint()).arg(res).arg(ERR_error_string(ERR_get_error(), 0)));
+		return {};
+	} else if (auto zeroBytes = kDecryptSize - res) {
+		auto resultBytes = gsl::make_span(result);
+		bytes::move(resultBytes.subspan(zeroBytes - res, res), resultBytes.subspan(0, res));
+		bytes::set_with_const(resultBytes.subspan(0, zeroBytes - res), gsl::byte{});
+	}
+	return result;
+}
+
+bytes::vector RSAPublicKey::Private::encryptOAEPpadding(bytes::const_span data) const {
+	Expects(valid());
+
+	const auto resultSize = RSA_size(_rsa);
+	auto result = bytes::vector(resultSize, gsl::byte{});
+	const auto encryptedSize = RSA_public_encrypt(
+		data.size(),
+		reinterpret_cast<const unsigned char*>(data.data()),
+		reinterpret_cast<unsigned char*>(result.data()),
+		_rsa,
+		RSA_PKCS1_OAEP_PADDING);
+	if (encryptedSize != resultSize) {
+		ERR_load_crypto_strings();
+		LOG(("RSA Error: RSA_public_encrypt failed, "
+			"key fp: %1, result: %2, error: %3"
+			).arg(fingerprint()
+			).arg(encryptedSize
+			).arg(ERR_error_string(ERR_get_error(), 0)
+			));
+		return {};
+	}
+	return result;
+}
+
+RSAPublicKey::Private::~Private() {
+	RSA_free(_rsa);
+}
+
+void RSAPublicKey::Private::computeFingerprint() {
+	Expects(valid());
+
+	const BIGNUM *n, *e;
+	mtpBuffer string;
+	RSA_get0_key(_rsa, &n, &e, nullptr);
+	MTP_bytes(ToBytes(n)).write(string);
+	MTP_bytes(ToBytes(e)).write(string);
+
+	uchar sha1Buffer[20];
+	_fingerprint = *(uint64*)(hashSha1(&string[0], string.size() * sizeof(mtpPrime), sha1Buffer) + 3);
+}
+
+bytes::vector RSAPublicKey::Private::ToBytes(const BIGNUM *number) {
+	auto size = BN_num_bytes(number);
+	auto result = bytes::vector(size, gsl::byte{});
+	BN_bn2bin(number, reinterpret_cast<unsigned char*>(result.data()));
+	return result;
+}
+
 RSAPublicKey::RSAPublicKey(bytes::const_span key)
 : _private(std::make_shared<Private>(key)) {
 }
@@ -229,35 +255,40 @@ RSAPublicKey::RSAPublicKey(
 : _private(std::make_shared<Private>(nBytes, eBytes)) {
 }
 
-bool RSAPublicKey::isValid() const {
-	return _private && _private->isValid();
+bool RSAPublicKey::empty() const {
+	return !_private;
 }
 
-uint64 RSAPublicKey::getFingerPrint() const {
-	Expects(isValid());
-	return _private->getFingerPrint();
+bool RSAPublicKey::valid() const {
+	return !empty() && _private->valid();
+}
+
+uint64 RSAPublicKey::fingerprint() const {
+	Expects(valid());
+
+	return _private->fingerprint();
 }
 
 bytes::vector RSAPublicKey::getN() const {
-	Expects(isValid());
+	Expects(valid());
 
 	return _private->getN();
 }
 
 bytes::vector RSAPublicKey::getE() const {
-	Expects(isValid());
+	Expects(valid());
 
 	return _private->getE();
 }
 
 bytes::vector RSAPublicKey::encrypt(bytes::const_span data) const {
-	Expects(isValid());
+	Expects(valid());
 
 	return _private->encrypt(data);
 }
 
 bytes::vector RSAPublicKey::decrypt(bytes::const_span data) const {
-	Expects(isValid());
+	Expects(valid());
 
 	return _private->decrypt(data);
 }
diff --git a/Telegram/SourceFiles/mtproto/rsa_public_key.h b/Telegram/SourceFiles/mtproto/rsa_public_key.h
index 8e748d8a5..402b17426 100644
--- a/Telegram/SourceFiles/mtproto/rsa_public_key.h
+++ b/Telegram/SourceFiles/mtproto/rsa_public_key.h
@@ -26,19 +26,20 @@ public:
 	// or in "-----BEGIN PUBLIC KEY----- ..." format
 	explicit RSAPublicKey(bytes::const_span key);
 
-	bool isValid() const;
-	uint64 getFingerPrint() const;
-	bytes::vector getN() const;
-	bytes::vector getE() const;
+	[[nodiscard]] bool empty() const;
+	[[nodiscard]] bool valid() const;
+	[[nodiscard]] uint64 fingerprint() const;
+	[[nodiscard]] bytes::vector getN() const;
+	[[nodiscard]] bytes::vector getE() const;
 
 	// data has exactly 256 chars to be encrypted
-	bytes::vector encrypt(bytes::const_span data) const;
+	[[nodiscard]] bytes::vector encrypt(bytes::const_span data) const;
 
 	// data has exactly 256 chars to be decrypted
-	bytes::vector decrypt(bytes::const_span data) const;
+	[[nodiscard]] bytes::vector decrypt(bytes::const_span data) const;
 
 	// data has lequal than 215 chars to be decrypted
-	bytes::vector encryptOAEPpadding(bytes::const_span data) const;
+	[[nodiscard]] bytes::vector encryptOAEPpadding(bytes::const_span data) const;
 
 private:
 	class Private;
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 061bac330..a08315852 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "base/timer.h"
 #include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_proxy_data.h"
 
 #include <QtCore/QTimer>
 
diff --git a/Telegram/SourceFiles/settings/settings_advanced.cpp b/Telegram/SourceFiles/settings/settings_advanced.cpp
index 26539db81..f00fc5482 100644
--- a/Telegram/SourceFiles/settings/settings_advanced.cpp
+++ b/Telegram/SourceFiles/settings/settings_advanced.cpp
@@ -48,7 +48,7 @@ void SetupConnectionType(not_null<Ui::VerticalLayout*> container) {
 #ifndef TDESKTOP_DISABLE_NETWORK_PROXY
 	const auto connectionType = [] {
 		const auto transport = MTP::dctransport();
-		if (Global::ProxySettings() != ProxyData::Settings::Enabled) {
+		if (Global::ProxySettings() != MTP::ProxyData::Settings::Enabled) {
 			return transport.isEmpty()
 				? tr::lng_connection_auto_connecting(tr::now)
 				: tr::lng_connection_auto(tr::now, lt_transport, transport);
diff --git a/Telegram/SourceFiles/storage/localstorage.cpp b/Telegram/SourceFiles/storage/localstorage.cpp
index 4ce04ab92..821d492d2 100644
--- a/Telegram/SourceFiles/storage/localstorage.cpp
+++ b/Telegram/SourceFiles/storage/localstorage.cpp
@@ -1264,7 +1264,7 @@ bool _readSetting(quint32 blockId, QDataStream &stream, int version, ReadSetting
 		stream >> v;
 		if (!_checkStreamStatus(stream)) return false;
 
-		ProxyData proxy;
+		MTP::ProxyData proxy;
 		switch (v) {
 		case dbictHttpProxy:
 		case dbictTcpProxy: {
@@ -1274,14 +1274,14 @@ bool _readSetting(quint32 blockId, QDataStream &stream, int version, ReadSetting
 
 			proxy.port = uint32(port);
 			proxy.type = (v == dbictTcpProxy)
-				? ProxyData::Type::Socks5
-				: ProxyData::Type::Http;
+				? MTP::ProxyData::Type::Socks5
+				: MTP::ProxyData::Type::Http;
 		} break;
 		};
-		Global::SetSelectedProxy(proxy ? proxy : ProxyData());
+		Global::SetSelectedProxy(proxy ? proxy : MTP::ProxyData());
 		Global::SetProxySettings(proxy
-			? ProxyData::Settings::Enabled
-			: ProxyData::Settings::System);
+			? MTP::ProxyData::Settings::Enabled
+			: MTP::ProxyData::Settings::System);
 		if (proxy) {
 			Global::SetProxiesList({ 1, proxy });
 		} else {
@@ -1299,20 +1299,20 @@ bool _readSetting(quint32 blockId, QDataStream &stream, int version, ReadSetting
 
 		const auto readProxy = [&] {
 			qint32 proxyType, port;
-			ProxyData proxy;
+			MTP::ProxyData proxy;
 			stream >> proxyType >> proxy.host >> port >> proxy.user >> proxy.password;
 			proxy.port = port;
 			proxy.type = (proxyType == dbictTcpProxy)
-				? ProxyData::Type::Socks5
+				? MTP::ProxyData::Type::Socks5
 				: (proxyType == dbictHttpProxy)
-				? ProxyData::Type::Http
-				: (proxyType == kProxyTypeShift + int(ProxyData::Type::Socks5))
-				? ProxyData::Type::Socks5
-				: (proxyType == kProxyTypeShift + int(ProxyData::Type::Http))
-				? ProxyData::Type::Http
-				: (proxyType == kProxyTypeShift + int(ProxyData::Type::Mtproto))
-				? ProxyData::Type::Mtproto
-				: ProxyData::Type::None;
+				? MTP::ProxyData::Type::Http
+				: (proxyType == kProxyTypeShift + int(MTP::ProxyData::Type::Socks5))
+				? MTP::ProxyData::Type::Socks5
+				: (proxyType == kProxyTypeShift + int(MTP::ProxyData::Type::Http))
+				? MTP::ProxyData::Type::Http
+				: (proxyType == kProxyTypeShift + int(MTP::ProxyData::Type::Mtproto))
+				? MTP::ProxyData::Type::Mtproto
+				: MTP::ProxyData::Type::None;
 			return proxy;
 		};
 		if (connectionType == dbictProxiesListOld
@@ -1327,7 +1327,7 @@ bool _readSetting(quint32 blockId, QDataStream &stream, int version, ReadSetting
 				index -= (index > 0 ? count : -count);
 			}
 
-			auto list = std::vector<ProxyData>();
+			auto list = std::vector<MTP::ProxyData>();
 			for (auto i = 0; i < count; ++i) {
 				const auto proxy = readProxy();
 				if (proxy) {
@@ -1345,29 +1345,29 @@ bool _readSetting(quint32 blockId, QDataStream &stream, int version, ReadSetting
 			if (connectionType == dbictProxiesListOld) {
 				settings = static_cast<qint32>(
 					(index > 0 && index <= list.size()
-						? ProxyData::Settings::Enabled
-						: ProxyData::Settings::System));
+						? MTP::ProxyData::Settings::Enabled
+						: MTP::ProxyData::Settings::System));
 				index = std::abs(index);
 			}
 			if (index > 0 && index <= list.size()) {
 				Global::SetSelectedProxy(list[index - 1]);
 			} else {
-				Global::SetSelectedProxy(ProxyData());
+				Global::SetSelectedProxy(MTP::ProxyData());
 			}
 
-			const auto unchecked = static_cast<ProxyData::Settings>(settings);
+			const auto unchecked = static_cast<MTP::ProxyData::Settings>(settings);
 			switch (unchecked) {
-			case ProxyData::Settings::Enabled:
+			case MTP::ProxyData::Settings::Enabled:
 				Global::SetProxySettings(Global::SelectedProxy()
-					? ProxyData::Settings::Enabled
-					: ProxyData::Settings::System);
+					? MTP::ProxyData::Settings::Enabled
+					: MTP::ProxyData::Settings::System);
 				break;
-			case ProxyData::Settings::Disabled:
-			case ProxyData::Settings::System:
+			case MTP::ProxyData::Settings::Disabled:
+			case MTP::ProxyData::Settings::System:
 				Global::SetProxySettings(unchecked);
 				break;
 			default:
-				Global::SetProxySettings(ProxyData::Settings::System);
+				Global::SetProxySettings(MTP::ProxyData::Settings::System);
 				break;
 			}
 			Global::SetUseProxyForCalls(calls == 1);
@@ -1381,14 +1381,14 @@ bool _readSetting(quint32 blockId, QDataStream &stream, int version, ReadSetting
 				Global::SetSelectedProxy(proxy);
 				if (connectionType == dbictTcpProxy
 					|| connectionType == dbictHttpProxy) {
-					Global::SetProxySettings(ProxyData::Settings::Enabled);
+					Global::SetProxySettings(MTP::ProxyData::Settings::Enabled);
 				} else {
-					Global::SetProxySettings(ProxyData::Settings::System);
+					Global::SetProxySettings(MTP::ProxyData::Settings::System);
 				}
 			} else {
 				Global::SetProxiesList({});
-				Global::SetSelectedProxy(ProxyData());
-				Global::SetProxySettings(ProxyData::Settings::System);
+				Global::SetSelectedProxy(MTP::ProxyData());
+				Global::SetProxySettings(MTP::ProxyData::Settings::System);
 			}
 		}
 		Core::App().refreshGlobalProxy();
@@ -2646,7 +2646,7 @@ void writeSettings() {
 	auto &proxies = Global::RefProxiesList();
 	const auto &proxy = Global::SelectedProxy();
 	auto proxyIt = ranges::find(proxies, proxy);
-	if (proxy.type != ProxyData::Type::None
+	if (proxy.type != MTP::ProxyData::Type::None
 		&& proxyIt == end(proxies)) {
 		proxies.push_back(proxy);
 		proxyIt = end(proxies) - 1;
diff --git a/Telegram/SourceFiles/window/window_connecting_widget.cpp b/Telegram/SourceFiles/window/window_connecting_widget.cpp
index 154614247..622c5e6b2 100644
--- a/Telegram/SourceFiles/window/window_connecting_widget.cpp
+++ b/Telegram/SourceFiles/window/window_connecting_widget.cpp
@@ -271,7 +271,7 @@ void ConnectionState::refreshState() {
 		const auto under = _widget && _widget->isOver();
 		const auto mtp = MTP::dcstate();
 		const auto throughProxy
-			= (Global::ProxySettings() == ProxyData::Settings::Enabled);
+			= (Global::ProxySettings() == MTP::ProxyData::Settings::Enabled);
 		if (mtp == MTP::ConnectingState
 			|| mtp == MTP::DisconnectedState
 			|| (mtp < 0 && mtp > -600)) {
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index 5344f6e10..f86c004ff 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -34,6 +34,14 @@
       '<(src_loc)',
     ],
     'sources': [
+      '<(src_loc)/mtproto/details/mtproto_dc_key_checker.cpp',
+      '<(src_loc)/mtproto/details/mtproto_dc_key_checker.h',
+      '<(src_loc)/mtproto/details/mtproto_dc_key_creator.cpp',
+      '<(src_loc)/mtproto/details/mtproto_dc_key_creator.h',
+      '<(src_loc)/mtproto/mtproto_dh_utils.cpp',
+      '<(src_loc)/mtproto/mtproto_dh_utils.h',
+      '<(src_loc)/mtproto/mtproto_proxy_data.cpp',
+      '<(src_loc)/mtproto/mtproto_proxy_data.h',
       '<(src_loc)/mtproto/mtp_abstract_socket.cpp',
       '<(src_loc)/mtproto/mtp_abstract_socket.h',
       '<(src_loc)/mtproto/mtp_tcp_socket.cpp',

From 1524b4a9300a42141a67160ccd0ded6881ca9a9d Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 14 Nov 2019 10:13:17 +0300
Subject: [PATCH 09/91] Allow creating temporary keys.

---
 Telegram/Resources/tl/mtproto.tl              |   2 +
 Telegram/SourceFiles/mtproto/connection.cpp   | 451 +++++++++---------
 Telegram/SourceFiles/mtproto/connection.h     |  16 +-
 Telegram/SourceFiles/mtproto/core_types.h     |   1 +
 .../details/mtproto_dc_key_creator.cpp        |  45 +-
 .../mtproto/details/mtproto_dc_key_creator.h  |   6 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 177 +++----
 Telegram/SourceFiles/mtproto/session.h        |  28 +-
 8 files changed, 381 insertions(+), 345 deletions(-)

diff --git a/Telegram/Resources/tl/mtproto.tl b/Telegram/Resources/tl/mtproto.tl
index 83a770292..4b92c3e6e 100644
--- a/Telegram/Resources/tl/mtproto.tl
+++ b/Telegram/Resources/tl/mtproto.tl
@@ -21,6 +21,8 @@ p_q_inner_data_dc#a9f55f95 pq:string p:string q:string nonce:int128 server_nonce
 p_q_inner_data_temp#3c6a84d4 pq:string p:string q:string nonce:int128 server_nonce:int128 new_nonce:int256 expires_in:int = P_Q_inner_data;
 p_q_inner_data_temp_dc#56fddf88 pq:string p:string q:string nonce:int128 server_nonce:int128 new_nonce:int256 dc:int expires_in:int = P_Q_inner_data;
 
+bind_auth_key_inner#75a3f765 nonce:long temp_auth_key_id:long perm_auth_key_id:long temp_session_id:long expires_at:int = BindAuthKeyInner;
+
 server_DH_params_fail#79cb045d nonce:int128 server_nonce:int128 new_nonce_hash:int128 = Server_DH_Params;
 server_DH_params_ok#d0e8075c nonce:int128 server_nonce:int128 encrypted_answer:string = Server_DH_Params;
 
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index f48b90189..318330699 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -47,8 +47,9 @@ constexpr auto kMinReceiveTimeout = crl::time(4000);
 constexpr auto kMaxReceiveTimeout = crl::time(64000);
 constexpr auto kMarkConnectionOldTimeout = crl::time(192000);
 constexpr auto kPingDelayDisconnect = 60;
-constexpr auto kPingSendAfter = crl::time(30000);
-constexpr auto kPingSendAfterForce = crl::time(45000);
+constexpr auto kPingSendAfter = 30 * crl::time(1000);
+constexpr auto kPingSendAfterForce = 45 * crl::time(1000);
+constexpr auto kCheckKeyExpiresIn = TimeId(3600);
 constexpr auto kTestModeDcIdShift = 10000;
 
 // If we can't connect for this time we will ask _instance to update config.
@@ -174,7 +175,7 @@ void ConnectionPrivate::appendTestConnection(
 	connect(weak, &AbstractConnection::receivedSome, [=] {
 		onReceivedSome();
 	});
-	firstSentAt = 0;
+	_firstSentAt = 0;
 	if (_oldConnection) {
 		_oldConnection = false;
 		DEBUG_LOG(("This connection marked as not old!"));
@@ -238,7 +239,7 @@ ConnectionPrivate::ConnectionPrivate(
 , _waitForReceived(kMinReceiveTimeout)
 , _waitForConnected(kMinConnectedTimeout)
 , _pingSender(thread, [=] { sendPingByTimer(); })
-, sessionData(data) {
+, _sessionData(data) {
 	Expects(_shiftedDcId != 0);
 
 	moveToThread(thread);
@@ -247,13 +248,13 @@ ConnectionPrivate::ConnectionPrivate(
 	connect(thread, &QThread::finished, this, [=] { finishAndDestroy(); });
 	connect(this, SIGNAL(finished(internal::Connection*)), _instance, SLOT(connectionFinished(internal::Connection*)), Qt::QueuedConnection);
 
-	connect(sessionData->owner(), SIGNAL(authKeyCreated()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
-	connect(sessionData->owner(), SIGNAL(needToRestart()), this, SLOT(restartNow()), Qt::QueuedConnection);
-	connect(this, SIGNAL(needToReceive()), sessionData->owner(), SLOT(tryToReceive()), Qt::QueuedConnection);
-	connect(this, SIGNAL(stateChanged(qint32)), sessionData->owner(), SLOT(onConnectionStateChange(qint32)), Qt::QueuedConnection);
-	connect(sessionData->owner(), SIGNAL(needToSend()), this, SLOT(tryToSend()), Qt::QueuedConnection);
-	connect(sessionData->owner(), SIGNAL(needToPing()), this, SLOT(onPingSendForce()), Qt::QueuedConnection);
-	connect(this, SIGNAL(sessionResetDone()), sessionData->owner(), SLOT(onResetDone()), Qt::QueuedConnection);
+	connect(_sessionData->owner(), SIGNAL(authKeyCreated()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
+	connect(_sessionData->owner(), SIGNAL(needToRestart()), this, SLOT(restartNow()), Qt::QueuedConnection);
+	connect(this, SIGNAL(needToReceive()), _sessionData->owner(), SLOT(tryToReceive()), Qt::QueuedConnection);
+	connect(this, SIGNAL(stateChanged(qint32)), _sessionData->owner(), SLOT(onConnectionStateChange(qint32)), Qt::QueuedConnection);
+	connect(_sessionData->owner(), SIGNAL(needToSend()), this, SLOT(tryToSend()), Qt::QueuedConnection);
+	connect(_sessionData->owner(), SIGNAL(needToPing()), this, SLOT(onPingSendForce()), Qt::QueuedConnection);
+	connect(this, SIGNAL(sessionResetDone()), _sessionData->owner(), SLOT(onResetDone()), Qt::QueuedConnection);
 
 	static bool _registered = false;
 	if (!_registered) {
@@ -261,14 +262,14 @@ ConnectionPrivate::ConnectionPrivate(
 		qRegisterMetaType<QVector<quint64> >("QVector<quint64>");
 	}
 
-	connect(this, SIGNAL(needToSendAsync()), sessionData->owner(), SLOT(needToResumeAndSend()), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendAnythingAsync(qint64)), sessionData->owner(), SLOT(sendAnything(qint64)), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendHttpWaitAsync()), sessionData->owner(), SLOT(sendAnything()), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendPongAsync(quint64,quint64)), sessionData->owner(), SLOT(sendPong(quint64,quint64)), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendMsgsStateInfoAsync(quint64, QByteArray)), sessionData->owner(), SLOT(sendMsgsStateInfo(quint64,QByteArray)), Qt::QueuedConnection);
-	connect(this, SIGNAL(resendAsync(quint64,qint64,bool,bool)), sessionData->owner(), SLOT(resend(quint64,qint64,bool,bool)), Qt::QueuedConnection);
-	connect(this, SIGNAL(resendManyAsync(QVector<quint64>,qint64,bool,bool)), sessionData->owner(), SLOT(resendMany(QVector<quint64>,qint64,bool,bool)), Qt::QueuedConnection);
-	connect(this, SIGNAL(resendAllAsync()), sessionData->owner(), SLOT(resendAll()), Qt::QueuedConnection);
+	connect(this, SIGNAL(needToSendAsync()), _sessionData->owner(), SLOT(needToResumeAndSend()), Qt::QueuedConnection);
+	connect(this, SIGNAL(sendAnythingAsync(qint64)), _sessionData->owner(), SLOT(sendAnything(qint64)), Qt::QueuedConnection);
+	connect(this, SIGNAL(sendHttpWaitAsync()), _sessionData->owner(), SLOT(sendAnything()), Qt::QueuedConnection);
+	connect(this, SIGNAL(sendPongAsync(quint64,quint64)), _sessionData->owner(), SLOT(sendPong(quint64,quint64)), Qt::QueuedConnection);
+	connect(this, SIGNAL(sendMsgsStateInfoAsync(quint64, QByteArray)), _sessionData->owner(), SLOT(sendMsgsStateInfo(quint64,QByteArray)), Qt::QueuedConnection);
+	connect(this, SIGNAL(resendAsync(quint64,qint64,bool,bool)), _sessionData->owner(), SLOT(resend(quint64,qint64,bool,bool)), Qt::QueuedConnection);
+	connect(this, SIGNAL(resendManyAsync(QVector<quint64>,qint64,bool,bool)), _sessionData->owner(), SLOT(resendMany(QVector<quint64>,qint64,bool,bool)), Qt::QueuedConnection);
+	connect(this, SIGNAL(resendAllAsync()), _sessionData->owner(), SLOT(resendAll()), Qt::QueuedConnection);
 }
 
 void ConnectionPrivate::onConfigLoaded() {
@@ -327,14 +328,14 @@ bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 	_needSessionReset = false;
 
-	QWriteLocker locker1(sessionData->haveSentMutex());
-	QWriteLocker locker2(sessionData->toResendMutex());
-	QWriteLocker locker3(sessionData->toSendMutex());
-	QWriteLocker locker4(sessionData->wereAckedMutex());
-	auto &haveSent = sessionData->haveSentMap();
-	auto &toResend = sessionData->toResendMap();
-	auto &toSend = sessionData->toSendMap();
-	auto &wereAcked = sessionData->wereAckedMap();
+	QWriteLocker locker1(_sessionData->haveSentMutex());
+	QWriteLocker locker2(_sessionData->toResendMutex());
+	QWriteLocker locker3(_sessionData->toSendMutex());
+	QWriteLocker locker4(_sessionData->wereAckedMutex());
+	auto &haveSent = _sessionData->haveSentMap();
+	auto &toResend = _sessionData->toResendMap();
+	auto &toSend = _sessionData->toSendMap();
+	auto &wereAcked = _sessionData->wereAckedMap();
 
 	auto newId = base::unixtime::mtproto_msg_id();
 	auto setSeqNumbers = RequestMap();
@@ -400,13 +401,13 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 		}
 	}
 
-	uint64 session = rand_value<uint64>();
-	DEBUG_LOG(("MTP Info: creating new session after bad_msg_notification, setting random server_session %1").arg(session));
-	sessionData->setSession(session);
+	const auto sessionId = rand_value<uint64>();
+	DEBUG_LOG(("MTP Info: creating new session after bad_msg_notification, setting random server_session %1").arg(sessionId));
+	_sessionData->setSessionId(sessionId);
 
 	for (auto i = setSeqNumbers.cbegin(), e = setSeqNumbers.cend(); i != e; ++i) { // generate new seq_numbers
 		bool wasNeedAck = (*(i.value()->data() + 6) & 1);
-		*(i.value()->data() + 6) = sessionData->nextRequestSeqNumber(wasNeedAck);
+		*(i.value()->data() + 6) = _sessionData->nextRequestSeqNumber(wasNeedAck);
 	}
 	if (!replaces.isEmpty()) {
 		for (auto i = replaces.cbegin(), e = replaces.cend(); i != e; ++i) { // replace msgIds keys in all data structs
@@ -446,11 +447,11 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 		}
 	}
 
-	ackRequestData.clear();
-	resendRequestData.clear();
+	_ackRequestData.clear();
+	_resendRequestData.clear();
 	{
-		QWriteLocker locker5(sessionData->stateRequestMutex());
-		sessionData->stateRequestMap().clear();
+		QWriteLocker locker5(_sessionData->stateRequestMutex());
+		_sessionData->stateRequestMap().clear();
 	}
 
 	emit sessionResetDone();
@@ -460,15 +461,15 @@ mtpMsgId ConnectionPrivate::prepareToSend(SecureRequest &request, mtpMsgId curre
 	if (request->size() < 9) return 0;
 	mtpMsgId msgId = *(mtpMsgId*)(request->constData() + 4);
 	if (msgId) { // resending this request
-		QWriteLocker locker(sessionData->toResendMutex());
-		auto &toResend = sessionData->toResendMap();
+		QWriteLocker locker(_sessionData->toResendMutex());
+		auto &toResend = _sessionData->toResendMap();
 		const auto i = toResend.find(msgId);
 		if (i != toResend.cend()) {
 			toResend.erase(i);
 		}
 	} else {
 		msgId = *(mtpMsgId*)(request->data() + 4) = currentLastId;
-		*(request->data() + 6) = sessionData->nextRequestSeqNumber(request.needAck());
+		*(request->data() + 6) = _sessionData->nextRequestSeqNumber(request.needAck());
 	}
 	return msgId;
 }
@@ -479,12 +480,12 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 	mtpMsgId oldMsgId = *(mtpMsgId*)(request->constData() + 4);
 	if (oldMsgId != newId) {
 		if (oldMsgId) {
-			QWriteLocker locker(sessionData->toResendMutex());
+			QWriteLocker locker(_sessionData->toResendMutex());
 			// haveSentMutex() and wereAckedMutex() were locked in tryToSend()
 
-			auto &toResend = sessionData->toResendMap();
-			auto &wereAcked = sessionData->wereAckedMap();
-			auto &haveSent = sessionData->haveSentMap();
+			auto &toResend = _sessionData->toResendMap();
+			auto &wereAcked = _sessionData->wereAckedMap();
+			auto &haveSent = _sessionData->haveSentMap();
 
 			while (true) {
 				if (toResend.constFind(newId) == toResend.cend() && wereAcked.constFind(newId) == wereAcked.cend() && haveSent.constFind(newId) == haveSent.cend()) {
@@ -529,7 +530,7 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 				}
 			}
 		} else {
-			*(request->data() + 6) = sessionData->nextRequestSeqNumber(request.needAck());
+			*(request->data() + 6) = _sessionData->nextRequestSeqNumber(request.needAck());
 		}
 		*(mtpMsgId*)(request->data() + 4) = newId;
 	}
@@ -554,8 +555,8 @@ mtpMsgId ConnectionPrivate::placeToContainer(SecureRequest &toSendRequest, mtpMs
 }
 
 void ConnectionPrivate::tryToSend() {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData || !_connection) {
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData || !_connection) {
 		return;
 	}
 
@@ -603,27 +604,27 @@ void ConnectionPrivate::tryToSend() {
 	}
 
 	SecureRequest ackRequest, resendRequest, stateRequest, httpWaitRequest;
-	if (!prependOnly && !ackRequestData.isEmpty()) {
+	if (!prependOnly && !_ackRequestData.isEmpty()) {
 		ackRequest = SecureRequest::Serialize(MTPMsgsAck(
-			MTP_msgs_ack(MTP_vector<MTPlong>(ackRequestData))));
+			MTP_msgs_ack(MTP_vector<MTPlong>(_ackRequestData))));
 		ackRequest->msDate = crl::now(); // > 0 - can send without container
 		ackRequest->requestId = 0; // dont add to haveSent / wereAcked maps
 
-		ackRequestData.clear();
+		_ackRequestData.clear();
 	}
-	if (!prependOnly && !resendRequestData.isEmpty()) {
+	if (!prependOnly && !_resendRequestData.isEmpty()) {
 		resendRequest = SecureRequest::Serialize(MTPMsgResendReq(
-			MTP_msg_resend_req(MTP_vector<MTPlong>(resendRequestData))));
+			MTP_msg_resend_req(MTP_vector<MTPlong>(_resendRequestData))));
 		resendRequest->msDate = crl::now(); // > 0 - can send without container
 		resendRequest->requestId = 0; // dont add to haveSent / wereAcked maps
 
-		resendRequestData.clear();
+		_resendRequestData.clear();
 	}
 	if (!prependOnly) {
 		QVector<MTPlong> stateReq;
 		{
-			QWriteLocker locker(sessionData->stateRequestMutex());
-			auto &ids = sessionData->stateRequestMap();
+			QWriteLocker locker(_sessionData->stateRequestMutex());
+			auto &ids = _sessionData->stateRequestMap();
 			if (!ids.isEmpty()) {
 				stateReq.reserve(ids.size());
 				for (auto i = ids.cbegin(), e = ids.cend(); i != e; ++i) {
@@ -694,10 +695,10 @@ void ConnectionPrivate::tryToSend() {
 	bool needAnyResponse = false;
 	SecureRequest toSendRequest;
 	{
-		QWriteLocker locker1(sessionData->toSendMutex());
+		QWriteLocker locker1(_sessionData->toSendMutex());
 
 		auto toSendDummy = PreRequestMap();
-		auto &toSend = prependOnly ? toSendDummy : sessionData->toSendMap();
+		auto &toSend = prependOnly ? toSendDummy : _sessionData->toSendMap();
 		if (prependOnly) locker1.unlock();
 
 		uint32 toSendCount = toSend.size();
@@ -731,8 +732,8 @@ void ConnectionPrivate::tryToSend() {
 				if (toSendRequest.needAck()) {
 					toSendRequest->msDate = toSendRequest.isStateRequest() ? 0 : crl::now();
 
-					QWriteLocker locker2(sessionData->haveSentMutex());
-					auto &haveSent = sessionData->haveSentMap();
+					QWriteLocker locker2(_sessionData->haveSentMutex());
+					auto &haveSent = _sessionData->haveSentMap();
 					haveSent.insert(msgId, toSendRequest);
 
 					if (needsLayer && !toSendRequest->needsLayer) needsLayer = false;
@@ -761,8 +762,8 @@ void ConnectionPrivate::tryToSend() {
 
 					needAnyResponse = true;
 				} else {
-					QWriteLocker locker3(sessionData->wereAckedMutex());
-					sessionData->wereAckedMap().insert(msgId, toSendRequest->requestId);
+					QWriteLocker locker3(_sessionData->wereAckedMutex());
+					_sessionData->wereAckedMap().insert(msgId, toSendRequest->requestId);
 				}
 			}
 		} else { // send in container
@@ -798,12 +799,12 @@ void ConnectionPrivate::tryToSend() {
 			auto bigMsgId = base::unixtime::mtproto_msg_id();
 
 			// the fact of this lock is used in replaceMsgId()
-			QWriteLocker locker2(sessionData->haveSentMutex());
-			auto &haveSent = sessionData->haveSentMap();
+			QWriteLocker locker2(_sessionData->haveSentMutex());
+			auto &haveSent = _sessionData->haveSentMap();
 
 			// the fact of this lock is used in replaceMsgId()
-			QWriteLocker locker3(sessionData->wereAckedMutex());
-			auto &wereAcked = sessionData->wereAckedMap();
+			QWriteLocker locker3(_sessionData->wereAckedMutex());
+			auto &wereAcked = _sessionData->wereAckedMap();
 
 			// prepare "request-like" wrap for msgId vector
 			auto haveSentIdsWrap = SecureRequest::Prepare(idsWrapSize);
@@ -883,8 +884,8 @@ void ConnectionPrivate::tryToSend() {
 }
 
 void ConnectionPrivate::retryByTimer() {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData) return;
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData) return;
 
 	if (_retryTimeout < 3) {
 		++_retryTimeout;
@@ -893,14 +894,14 @@ void ConnectionPrivate::retryByTimer() {
 	} else if (_retryTimeout < 64000) {
 		_retryTimeout *= 2;
 	}
-	if (keyId == kRecreateKeyId) {
-		if (sessionData->getKey()) {
+	if (_keyId == kRecreateKeyId) {
+		if (_sessionData->getKey()) {
 			unlockKey();
 
-			QWriteLocker lock(sessionData->keyMutex());
-			sessionData->owner()->destroyKey();
+			QWriteLocker lock(_sessionData->keyMutex());
+			_sessionData->owner()->destroyKey();
 		}
-		keyId = 0;
+		_keyId = 0;
 	}
 	connectToServer();
 }
@@ -917,19 +918,19 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 			"connectToServer() called for finished connection!"));
 		return;
 	}
-	auto hasKey = true;
-	{
-		QReadLocker lockFinished(&sessionDataMutex);
-		if (!sessionData) {
-			DEBUG_LOG(("MTP Error: "
-				"connectToServer() called for stopped connection!"));
-			return;
-		}
-		_connectionOptions = std::make_unique<ConnectionOptions>(
-			sessionData->connectionOptions());
-		hasKey = (sessionData->getKey() != nullptr);
+
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData) {
+		DEBUG_LOG(("MTP Error: "
+			"connectToServer() called for stopped connection!"));
+		return;
 	}
-	auto bareDc = BareDcId(_shiftedDcId);
+	_connectionOptions = std::make_unique<ConnectionOptions>(
+		_sessionData->connectionOptions());
+	const auto hasKey = (_sessionData->getKey() != nullptr);
+	lockFinished.unlock();
+
+	const auto bareDc = BareDcId(_shiftedDcId);
 	_dcType = _instance->dcOptions()->dcType(_shiftedDcId);
 
 	// Use media_only addresses only if key for this dc is already created.
@@ -1028,27 +1029,27 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 }
 
 void ConnectionPrivate::restart() {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData) return;
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData) return;
 
 	DEBUG_LOG(("MTP Info: restarting Connection"));
 
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
 
-	auto key = sessionData->getKey();
+	auto key = _sessionData->getKey();
 	if (key) {
-		if (!sessionData->isCheckedKey()) {
+		if (!_sessionData->isCheckedKey()) {
 			// No destroying in case of an error.
 			//
 			//if (mayBeBadKey) {
 			//	clearMessages();
-			//	keyId = kRecreateKeyId;
+			//	_keyId = kRecreateKeyId;
 //				retryTimeout = 1; // no ddos please
 			//	LOG(("MTP Info: key may be bad and was not checked - but won't be destroyed, no log outs because of bad server right now..."));
 			//}
 		} else {
-			sessionData->setCheckedKey(false);
+			_sessionData->setCheckedKey(false);
 		}
 	}
 
@@ -1056,10 +1057,10 @@ void ConnectionPrivate::restart() {
 	doDisconnect();
 
 	lockFinished.relock();
-	if (sessionData && _needSessionReset) {
+	if (_sessionData && _needSessionReset) {
 		resetSession();
 	}
-	restarted = true;
+	_restarted = true;
 	if (_retryTimer.isActive()) return;
 
 	DEBUG_LOG(("MTP Info: restart timeout: %1ms").arg(_retryTimeout));
@@ -1084,7 +1085,7 @@ void ConnectionPrivate::onSentSome(uint64 size) {
 		}
 		_waitForReceivedTimer.callOnce(remain);
 	}
-	if (!firstSentAt) firstSentAt = crl::now();
+	if (!_firstSentAt) _firstSentAt = crl::now();
 }
 
 void ConnectionPrivate::onReceivedSome() {
@@ -1094,14 +1095,14 @@ void ConnectionPrivate::onReceivedSome() {
 	}
 	_oldConnectionTimer.callOnce(kMarkConnectionOldTimeout);
 	_waitForReceivedTimer.cancel();
-	if (firstSentAt > 0) {
-		const auto ms = crl::now() - firstSentAt;
+	if (_firstSentAt > 0) {
+		const auto ms = crl::now() - _firstSentAt;
 		DEBUG_LOG(("MTP Info: response in %1ms, _waitForReceived: %2ms").arg(ms).arg(_waitForReceived));
 
 		if (ms > 0 && ms * 2 < _waitForReceived) {
 			_waitForReceived = qMax(ms * 2, kMinReceiveTimeout);
 		}
-		firstSentAt = -1;
+		_firstSentAt = -1;
 	}
 }
 
@@ -1150,7 +1151,7 @@ void ConnectionPrivate::waitReceivedFailed() {
 		_waitForReceived *= 2;
 	}
 	doDisconnect();
-	restarted = true;
+	_restarted = true;
 	if (_retryTimer.isActive()) {
 		return;
 	}
@@ -1170,7 +1171,7 @@ void ConnectionPrivate::waitConnectedFailed() {
 	}
 
 	connectingTimedOut();
-	restarted = true;
+	_restarted = true;
 
 	DEBUG_LOG(("MTP Info: immediate restart!"));
 	InvokeQueued(this, [=] { connectToServer(); });
@@ -1191,14 +1192,14 @@ void ConnectionPrivate::doDisconnect() {
 	destroyAllConnections();
 
 	{
-		QReadLocker lockFinished(&sessionDataMutex);
-		if (sessionData) {
+		QReadLocker lockFinished(&_sessionDataMutex);
+		if (_sessionData) {
 			unlockKey();
 		}
 	}
 
 	setState(DisconnectedState);
-	restarted = false;
+	_restarted = false;
 }
 
 void ConnectionPrivate::finishAndDestroy() {
@@ -1221,8 +1222,8 @@ void ConnectionPrivate::requestCDNConfig() {
 }
 
 void ConnectionPrivate::handleReceived() {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData) return;
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData) return;
 
 	onReceivedSome();
 
@@ -1231,17 +1232,17 @@ void ConnectionPrivate::handleReceived() {
 		restart();
 	};
 
-	ReadLockerAttempt lock(sessionData->keyMutex());
+	ReadLockerAttempt lock(_sessionData->keyMutex());
 	if (!lock) {
 		DEBUG_LOG(("MTP Error: auth_key for dc %1 busy, cant lock").arg(_shiftedDcId));
 		clearMessages();
-		keyId = 0;
+		_keyId = 0;
 
 		return restartOnError();
 	}
 
-	auto key = sessionData->getKey();
-	if (!key || key->keyId() != keyId) {
+	auto key = _sessionData->getKey();
+	if (!key || key->keyId() != _keyId) {
 		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
 		return restartOnError();
 	}
@@ -1262,8 +1263,8 @@ void ConnectionPrivate::handleReceived() {
 
 			return restartOnError();
 		}
-		if (keyId != *(uint64*)ints) {
-			LOG(("TCP Error: bad auth_key_id %1 instead of %2 received").arg(keyId).arg(*(uint64*)ints));
+		if (_keyId != *(uint64*)ints) {
+			LOG(("TCP Error: bad auth_key_id %1 instead of %2 received").arg(_keyId).arg(*(uint64*)ints));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(ints, intsCount * kIntSize).str()));
 
 			return restartOnError();
@@ -1347,7 +1348,7 @@ void ConnectionPrivate::handleReceived() {
 
 		TCP_LOG(("TCP Info: decrypted message %1,%2,%3 is %4 len").arg(msgId).arg(seqNo).arg(Logs::b(needAck)).arg(fullDataLength));
 
-		uint64 serverSession = sessionData->getSession();
+		uint64 serverSession = _sessionData->getSessionId();
 		if (session != serverSession) {
 			LOG(("MTP Error: bad server session received"));
 			TCP_LOG(("MTP Error: bad server session %1 instead of %2 in message received").arg(session).arg(serverSession));
@@ -1365,7 +1366,7 @@ void ConnectionPrivate::handleReceived() {
 		}
 
 		bool badTime = false;
-		uint64 mySalt = sessionData->getSalt();
+		uint64 mySalt = _sessionData->getSalt();
 		if (serverTime > clientTime + 60 || serverTime + 300 < clientTime) {
 			DEBUG_LOG(("MTP Info: bad server time from msg_id: %1, my time: %2").arg(serverTime).arg(clientTime));
 			badTime = true;
@@ -1375,11 +1376,11 @@ void ConnectionPrivate::handleReceived() {
 		if (serverSalt != mySalt) {
 			if (!badTime) {
 				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2, updating...").arg(serverSalt).arg(mySalt));
-				sessionData->setSalt(serverSalt);
+				_sessionData->setSalt(serverSalt);
 				if (setState(ConnectedState, ConnectingState)) { // only connected
-					if (restarted) {
+					if (_restarted) {
 						emit resendAllAsync();
-						restarted = false;
+						_restarted = false;
 					}
 				}
 			} else {
@@ -1389,7 +1390,7 @@ void ConnectionPrivate::handleReceived() {
 			serverSalt = 0; // dont pass to handle method, so not to lock in setSalt()
 		}
 
-		if (needAck) ackRequestData.push_back(MTP_long(msgId));
+		if (needAck) _ackRequestData.push_back(MTP_long(msgId));
 
 		auto res = HandleResult::Success; // if no need to handle, then succeed
 		auto from = decryptedInts + kEncryptedHeaderIntsCount;
@@ -1399,30 +1400,30 @@ void ConnectionPrivate::handleReceived() {
 
 		bool needToHandle = false;
 		{
-			QWriteLocker lock(sessionData->receivedIdsMutex());
-			needToHandle = sessionData->receivedIdsSet().registerMsgId(msgId, needAck);
+			QWriteLocker lock(_sessionData->receivedIdsMutex());
+			needToHandle = _sessionData->receivedIdsSet().registerMsgId(msgId, needAck);
 		}
 		if (needToHandle) {
 			res = handleOneReceived(from, end, msgId, serverTime, serverSalt, badTime);
 		}
 		{
-			QWriteLocker lock(sessionData->receivedIdsMutex());
-			sessionData->receivedIdsSet().shrink();
+			QWriteLocker lock(_sessionData->receivedIdsMutex());
+			_sessionData->receivedIdsSet().shrink();
 		}
 
 		// send acks
-		uint32 toAckSize = ackRequestData.size();
+		uint32 toAckSize = _ackRequestData.size();
 		if (toAckSize) {
-			DEBUG_LOG(("MTP Info: will send %1 acks, ids: %2").arg(toAckSize).arg(LogIdsVector(ackRequestData)));
+			DEBUG_LOG(("MTP Info: will send %1 acks, ids: %2").arg(toAckSize).arg(LogIdsVector(_ackRequestData)));
 			emit sendAnythingAsync(kAckSendWaiting);
 		}
 
 		bool emitSignal = false;
 		{
-			QReadLocker locker(sessionData->haveReceivedMutex());
-			emitSignal = !sessionData->haveReceivedResponses().isEmpty() || !sessionData->haveReceivedUpdates().isEmpty();
+			QReadLocker locker(_sessionData->haveReceivedMutex());
+			emitSignal = !_sessionData->haveReceivedResponses().isEmpty() || !_sessionData->haveReceivedUpdates().isEmpty();
 			if (emitSignal) {
-				DEBUG_LOG(("MTP Info: emitting needToReceive() - need to parse in another thread, %1 responses, %2 updates.").arg(sessionData->haveReceivedResponses().size()).arg(sessionData->haveReceivedUpdates().size()));
+				DEBUG_LOG(("MTP Info: emitting needToReceive() - need to parse in another thread, %1 responses, %2 updates.").arg(_sessionData->haveReceivedResponses().size()).arg(_sessionData->haveReceivedUpdates().size()));
 			}
 		}
 
@@ -1437,9 +1438,9 @@ void ConnectionPrivate::handleReceived() {
 		}
 		_retryTimeout = 1; // reset restart() timer
 
-		if (!sessionData->isCheckedKey()) {
+		if (!_sessionData->isCheckedKey()) {
 			DEBUG_LOG(("MTP Info: marked auth key as checked"));
-			sessionData->setCheckedKey(true);
+			_sessionData->setCheckedKey(true);
 		}
 		_startedConnectingAt = crl::time(0);
 
@@ -1506,7 +1507,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			}
 
 			bool needAck = (inSeqNo.v & 0x01);
-			if (needAck) ackRequestData.push_back(inMsgId);
+			if (needAck) _ackRequestData.push_back(inMsgId);
 
 			DEBUG_LOG(("Message Info: message from container, msg_id: %1, needAck: %2").arg(inMsgId.v).arg(Logs::b(needAck)));
 
@@ -1517,8 +1518,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 
 			bool needToHandle = false;
 			{
-				QWriteLocker lock(sessionData->receivedIdsMutex());
-				needToHandle = sessionData->receivedIdsSet().registerMsgId(inMsgId.v, needAck);
+				QWriteLocker lock(_sessionData->receivedIdsMutex());
+				needToHandle = _sessionData->receivedIdsSet().registerMsgId(inMsgId.v, needAck);
 			}
 			auto res = HandleResult::Success; // if no need to handle, then succeed
 			if (needToHandle) {
@@ -1581,8 +1582,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				if (Logs::DebugEnabled()) {
 					SecureRequest request;
 					{
-						QWriteLocker locker(sessionData->haveSentMutex());
-						auto &haveSent = sessionData->haveSentMap();
+						QWriteLocker locker(_sessionData->haveSentMutex());
+						auto &haveSent = _sessionData->haveSentMap();
 
 						const auto i = haveSent.constFind(resendId);
 						if (i == haveSent.cend()) {
@@ -1615,7 +1616,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			}
 
 			if (needResend) { // bad msg_id or bad container
-				if (serverSalt) sessionData->setSalt(serverSalt);
+				if (serverSalt) _sessionData->setSalt(serverSalt);
 				base::unixtime::update(serverTime, true);
 
 				DEBUG_LOG(("Message Info: unixtime updated, now %1, resending in container...").arg(serverTime));
@@ -1623,7 +1624,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				resend(resendId, 0, true);
 			} else { // must create new session, because msg_id and msg_seqno are inconsistent
 				if (badTime) {
-					if (serverSalt) sessionData->setSalt(serverSalt);
+					if (serverSalt) _sessionData->setSalt(serverSalt);
 					base::unixtime::update(serverTime, true);
 					badTime = false;
 				}
@@ -1670,13 +1671,13 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 
 		uint64 serverSalt = data.vnew_server_salt().v;
-		sessionData->setSalt(serverSalt);
+		_sessionData->setSalt(serverSalt);
 		base::unixtime::update(serverTime);
 
 		if (setState(ConnectedState, ConnectingState)) { // maybe only connected
-			if (restarted) {
+			if (_restarted) {
 				emit resendAllAsync();
-				restarted = false;
+				_restarted = false;
 			}
 		}
 
@@ -1702,13 +1703,13 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 
 		QByteArray info(idsCount, Qt::Uninitialized);
 		{
-			QReadLocker lock(sessionData->receivedIdsMutex());
-			auto &receivedIds = sessionData->receivedIdsSet();
+			QReadLocker lock(_sessionData->receivedIdsMutex());
+			auto &receivedIds = _sessionData->receivedIdsSet();
 			auto minRecv = receivedIds.min();
 			auto maxRecv = receivedIds.max();
 
-			QReadLocker locker(sessionData->wereAckedMutex());
-			const auto &wereAcked = sessionData->wereAckedMap();
+			QReadLocker locker(_sessionData->wereAckedMutex());
+			const auto &wereAcked = _sessionData->wereAckedMap();
 			const auto wereAckedEnd = wereAcked.cend();
 
 			for (uint32 i = 0, l = idsCount; i < l; ++i) {
@@ -1753,15 +1754,15 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		DEBUG_LOG(("Message Info: msg state received, msgId %1, reqMsgId: %2, HEX states %3").arg(msgId).arg(reqMsgId).arg(Logs::mb(states.data(), states.length()).str()));
 		SecureRequest requestBuffer;
 		{ // find this request in session-shared sent requests map
-			QReadLocker locker(sessionData->haveSentMutex());
-			const auto &haveSent = sessionData->haveSentMap();
+			QReadLocker locker(_sessionData->haveSentMutex());
+			const auto &haveSent = _sessionData->haveSentMap();
 			const auto replyTo = haveSent.constFind(reqMsgId);
 			if (replyTo == haveSent.cend()) { // do not look in toResend, because we do not resend msgs_state_req requests
 				DEBUG_LOG(("Message Error: such message was not sent recently %1").arg(reqMsgId));
 				return (badTime ? HandleResult::Ignored : HandleResult::Success);
 			}
 			if (badTime) {
-				if (serverSalt) sessionData->setSalt(serverSalt); // requestsFixTimeSalt with no lookup
+				if (serverSalt) _sessionData->setSalt(serverSalt); // requestsFixTimeSalt with no lookup
 				base::unixtime::update(serverTime, true);
 
 				DEBUG_LOG(("Message Info: unixtime updated from mtpc_msgs_state_info, now %1").arg(serverTime));
@@ -1842,14 +1843,14 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		bool received = false;
 		MTPlong resMsgId = data.vanswer_msg_id();
 		{
-			QReadLocker lock(sessionData->receivedIdsMutex());
-			received = (sessionData->receivedIdsSet().lookup(resMsgId.v) != ReceivedMsgIds::State::NotFound);
+			QReadLocker lock(_sessionData->receivedIdsMutex());
+			received = (_sessionData->receivedIdsSet().lookup(resMsgId.v) != ReceivedMsgIds::State::NotFound);
 		}
 		if (received) {
-			ackRequestData.push_back(resMsgId);
+			_ackRequestData.push_back(resMsgId);
 		} else {
 			DEBUG_LOG(("Message Info: answer message %1 was not received, requesting...").arg(resMsgId.v));
-			resendRequestData.push_back(resMsgId);
+			_resendRequestData.push_back(resMsgId);
 		}
 	} return HandleResult::Success;
 
@@ -1869,14 +1870,14 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		bool received = false;
 		MTPlong resMsgId = data.vanswer_msg_id();
 		{
-			QReadLocker lock(sessionData->receivedIdsMutex());
-			received = (sessionData->receivedIdsSet().lookup(resMsgId.v) != ReceivedMsgIds::State::NotFound);
+			QReadLocker lock(_sessionData->receivedIdsMutex());
+			received = (_sessionData->receivedIdsSet().lookup(resMsgId.v) != ReceivedMsgIds::State::NotFound);
 		}
 		if (received) {
-			ackRequestData.push_back(resMsgId);
+			_ackRequestData.push_back(resMsgId);
 		} else {
 			DEBUG_LOG(("Message Info: answer message %1 was not received, requesting...").arg(resMsgId.v));
-			resendRequestData.push_back(resMsgId);
+			_resendRequestData.push_back(resMsgId);
 		}
 	} return HandleResult::Success;
 
@@ -1940,15 +1941,15 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			// Wait till a good response is received.
 			if (!_connectionOptions->inited) {
 				_connectionOptions->inited = true;
-				sessionData->notifyConnectionInited(*_connectionOptions);
+				_sessionData->notifyConnectionInited(*_connectionOptions);
 			}
 		}
 
 		auto requestId = wasSent(reqMsgId.v);
 		if (requestId && requestId != mtpRequestId(0xFFFFFFFF)) {
 			// Save rpc_result for processing in the main thread.
-			QWriteLocker locker(sessionData->haveReceivedMutex());
-			sessionData->haveReceivedResponses().insert(requestId, response);
+			QWriteLocker locker(_sessionData->haveReceivedMutex());
+			_sessionData->haveReceivedResponses().insert(requestId, response);
 		} else {
 			DEBUG_LOG(("RPC Info: requestId not found for msgId %1").arg(reqMsgId.v));
 		}
@@ -1972,13 +1973,13 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 
 		DEBUG_LOG(("Message Info: new server session created, unique_id %1, first_msg_id %2, server_salt %3").arg(data.vunique_id().v).arg(data.vfirst_msg_id().v).arg(data.vserver_salt().v));
-		sessionData->setSalt(data.vserver_salt().v);
+		_sessionData->setSalt(data.vserver_salt().v);
 
 		mtpMsgId firstMsgId = data.vfirst_msg_id().v;
 		QVector<quint64> toResend;
 		{
-			QReadLocker locker(sessionData->haveSentMutex());
-			const auto &haveSent = sessionData->haveSentMap();
+			QReadLocker locker(_sessionData->haveSentMutex());
+			const auto &haveSent = _sessionData->haveSentMap();
 			toResend.reserve(haveSent.size());
 			for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
 				if (i.key() >= firstMsgId) break;
@@ -1991,8 +1992,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		if (from > start) memcpy(update.data(), start, (from - start) * sizeof(mtpPrime));
 
 		// Notify main process about new session - need to get difference.
-		QWriteLocker locker(sessionData->haveReceivedMutex());
-		sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
+		QWriteLocker locker(_sessionData->haveReceivedMutex());
+		_sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
 	} return HandleResult::Success;
 
 	case mtpc_pong: {
@@ -2036,8 +2037,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		if (end > from) memcpy(update.data(), from, (end - from) * sizeof(mtpPrime));
 
 		// Notify main process about the new updates.
-		QWriteLocker locker(sessionData->haveReceivedMutex());
-		sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
+		QWriteLocker locker(_sessionData->haveReceivedMutex());
+		_sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
 
 		if (cons != mtpc_updatesTooLong
 			&& cons != mtpc_updateShortMessage
@@ -2113,7 +2114,7 @@ bool ConnectionPrivate::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 s
 
 	for (uint32 i = 0; i < idsCount; ++i) {
 		if (wasSent(ids[i].v)) {// found such msg_id in recent acked requests or in recent sent requests
-			if (serverSalt) sessionData->setSalt(serverSalt);
+			if (serverSalt) _sessionData->setSalt(serverSalt);
 			base::unixtime::update(serverTime, true);
 			return true;
 		}
@@ -2129,12 +2130,12 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 	auto clearedBecauseTooOld = std::vector<RPCCallbackClear>();
 	QVector<MTPlong> toAckMore;
 	{
-		QWriteLocker locker1(sessionData->wereAckedMutex());
-		auto &wereAcked = sessionData->wereAckedMap();
+		QWriteLocker locker1(_sessionData->wereAckedMutex());
+		auto &wereAcked = _sessionData->wereAckedMap();
 
 		{
-			QWriteLocker locker2(sessionData->haveSentMutex());
-			auto &haveSent = sessionData->haveSentMap();
+			QWriteLocker locker2(_sessionData->haveSentMutex());
+			auto &haveSent = _sessionData->haveSentMap();
 
 			for (uint32 i = 0; i < idsCount; ++i) {
 				mtpMsgId msgId = ids[i].v;
@@ -2164,8 +2165,8 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 					}
 				} else {
 					DEBUG_LOG(("Message Info: msgId %1 was not found in recent sent, while acking requests, searching in resend...").arg(msgId));
-					QWriteLocker locker3(sessionData->toResendMutex());
-					auto &toResend = sessionData->toResendMap();
+					QWriteLocker locker3(_sessionData->toResendMutex());
+					auto &toResend = _sessionData->toResendMap();
 					const auto reqIt = toResend.find(msgId);
 					if (reqIt != toResend.cend()) {
 						const auto reqId = reqIt.value();
@@ -2174,8 +2175,8 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 							moveToAcked = !_instance->hasCallbacks(reqId);
 						}
 						if (moveToAcked) {
-							QWriteLocker locker4(sessionData->toSendMutex());
-							auto &toSend = sessionData->toSendMap();
+							QWriteLocker locker4(_sessionData->toSendMutex());
+							auto &toSend = _sessionData->toSendMap();
 							const auto req = toSend.find(reqId);
 							if (req != toSend.cend()) {
 								wereAcked.insert(msgId, req.value()->requestId);
@@ -2238,13 +2239,13 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 		char state = states[i];
 		uint64 requestMsgId = ids[i].v;
 		{
-			QReadLocker locker(sessionData->haveSentMutex());
-			const auto &haveSent = sessionData->haveSentMap();
+			QReadLocker locker(_sessionData->haveSentMutex());
+			const auto &haveSent = _sessionData->haveSentMap();
 			const auto haveSentEnd = haveSent.cend();
 			if (haveSent.find(requestMsgId) == haveSentEnd) {
 				DEBUG_LOG(("Message Info: state was received for msgId %1, but request is not found, looking in resent requests...").arg(requestMsgId));
-				QWriteLocker locker2(sessionData->toResendMutex());
-				auto &toResend = sessionData->toResendMap();
+				QWriteLocker locker2(_sessionData->toResendMutex());
+				auto &toResend = _sessionData->toResendMap();
 				const auto reqIt = toResend.find(requestMsgId);
 				if (reqIt != toResend.cend()) {
 					if ((state & 0x07) != 0x04) { // was received
@@ -2286,8 +2287,8 @@ void ConnectionPrivate::resendMany(QVector<quint64> msgIds, qint64 msCanWait, bo
 
 void ConnectionPrivate::onConnected(
 		not_null<AbstractConnection*> connection) {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData) return;
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData) return;
 
 	disconnect(connection, &AbstractConnection::connected, nullptr, nullptr);
 	if (!connection->isConnected()) {
@@ -2372,38 +2373,40 @@ void ConnectionPrivate::removeTestConnection(
 }
 
 void ConnectionPrivate::updateAuthKey() {
-	QReadLocker lockFinished(&sessionDataMutex);
-	if (!sessionData || !_connection) return;
+	QReadLocker lockFinished(&_sessionDataMutex);
+	if (!_sessionData || !_connection) {
+		return;
+	}
 
 	DEBUG_LOG(("AuthKey Info: Connection updating key from Session, dc %1").arg(_shiftedDcId));
 	uint64 newKeyId = 0;
 	{
-		ReadLockerAttempt lock(sessionData->keyMutex());
+		ReadLockerAttempt lock(_sessionData->keyMutex());
 		if (!lock) {
 			DEBUG_LOG(("MTP Info: could not lock auth_key for read, waiting signal emit"));
 			clearMessages();
-			keyId = newKeyId;
+			_keyId = newKeyId;
 			return; // some other connection is getting key
 		}
-		auto key = sessionData->getKey();
+		auto key = _sessionData->getKey();
 		newKeyId = key ? key->keyId() : 0;
 	}
-	if (keyId != newKeyId) {
+	if (_keyId != newKeyId) {
 		clearMessages();
-		keyId = newKeyId;
+		_keyId = newKeyId;
 	}
-	DEBUG_LOG(("AuthKey Info: Connection update key from Session, dc %1 result: %2").arg(_shiftedDcId).arg(Logs::mb(&keyId, sizeof(keyId)).str()));
-	if (keyId) {
+	DEBUG_LOG(("AuthKey Info: Connection update key from Session, dc %1 result: %2").arg(_shiftedDcId).arg(Logs::mb(&_keyId, sizeof(_keyId)).str()));
+	if (_keyId) {
 		return authKeyCreated();
 	}
 
 	DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), will be creating auth_key"));
 	lockKey();
 
-	const auto &key = sessionData->getKey();
+	const auto &key = _sessionData->getKey();
 	if (key) {
-		if (keyId != key->keyId()) clearMessages();
-		keyId = key->keyId();
+		if (_keyId != key->keyId()) clearMessages();
+		_keyId = key->keyId();
 		unlockKey();
 		return authKeyCreated();
 	} else if (_instance->isKeysDestroyer()) {
@@ -2425,17 +2428,17 @@ void ConnectionPrivate::createDcKey() {
 		_keyCreator = nullptr;
 
 		if (result) {
-			QReadLocker lockFinished(&sessionDataMutex);
-			if (!sessionData) return;
+			QReadLocker lockFinished(&_sessionDataMutex);
+			if (!_sessionData) return;
 
-			sessionData->setSalt(result->serverSalt);
+			_sessionData->setSalt(result->serverSalt);
 
 			auto authKey = std::move(result->key);
 
 			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(authKey->keyId()).arg(result->serverSalt));
 
-			sessionData->owner()->notifyKeyCreated(std::move(authKey)); // slot will call authKeyCreated()
-			sessionData->clear(_instance);
+			_sessionData->owner()->notifyKeyCreated(std::move(authKey)); // slot will call authKeyCreated()
+			_sessionData->clear(_instance);
 			unlockKey();
 		} else if (result.error() == Error::UnknownPublicKey) {
 			if (_dcType == DcType::Cdn) {
@@ -2449,16 +2452,20 @@ void ConnectionPrivate::createDcKey() {
 			restart();
 		}
 	};
+	const auto expireIn = (GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift)
+		? kCheckKeyExpiresIn
+		: TimeId(0);
 	_keyCreator = std::make_unique<DcKeyCreator>(
 		BareDcId(_shiftedDcId),
 		getProtocolDcId(),
 		_connection.get(),
 		_instance->dcOptions(),
-		std::move(delegate));
+		std::move(delegate),
+		expireIn);
 }
 
 void ConnectionPrivate::clearMessages() {
-	if (keyId && keyId != kRecreateKeyId && _connection) {
+	if (_keyId && _keyId != kRecreateKeyId && _connection) {
 		_connection->received().clear();
 	}
 }
@@ -2470,11 +2477,11 @@ void ConnectionPrivate::authKeyCreated() {
 		handleReceived();
 	});
 
-	if (sessionData->getSalt()) { // else receive salt in bad_server_salt first, then try to send all the requests
+	if (_sessionData->getSalt()) { // else receive salt in bad_server_salt first, then try to send all the requests
 		setState(ConnectedState);
-		if (restarted) {
+		if (_restarted) {
 			emit resendAllAsync();
-			restarted = false;
+			_restarted = false;
 		}
 	}
 
@@ -2511,7 +2518,7 @@ void ConnectionPrivate::handleError(int errorCode) {
 		if (_dcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
 			LOG(("MTP Info: -404 error received in CDN dc %1, assuming it was destroyed, recreating.").arg(_shiftedDcId));
 			clearMessages();
-			keyId = kRecreateKeyId;
+			_keyId = kRecreateKeyId;
 			return restart();
 		} else {
 			LOG(("MTP Info: -404 error received, informing instance."));
@@ -2543,7 +2550,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		return false;
 	}
 
-	auto lock = ReadLockerAttempt(sessionData->keyMutex());
+	auto lock = ReadLockerAttempt(_sessionData->keyMutex());
 	if (!lock) {
 		DEBUG_LOG(("MTP Info: could not lock key for read in sendBuffer(), dc %1, restarting...").arg(_shiftedDcId));
 
@@ -2552,8 +2559,8 @@ bool ConnectionPrivate::sendSecureRequest(
 		return false;
 	}
 
-	auto key = sessionData->getKey();
-	if (!key || key->keyId() != keyId) {
+	auto key = _sessionData->getKey();
+	if (!key || key->keyId() != _keyId) {
 		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
 
 		lockFinished.unlock();
@@ -2561,8 +2568,8 @@ bool ConnectionPrivate::sendSecureRequest(
 		return false;
 	}
 
-	auto session = sessionData->getSession();
-	auto salt = sessionData->getSalt();
+	auto session = _sessionData->getSessionId();
+	auto salt = _sessionData->getSalt();
 
 	memcpy(request->data() + 0, &salt, 2 * sizeof(mtpPrime));
 	memcpy(request->data() + 2, &session, 2 * sizeof(mtpPrime));
@@ -2580,7 +2587,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		(fullSize - padding) * sizeof(mtpPrime),
 		encryptedSHA);
 
-	auto packet = _connection->prepareSecurePacket(keyId, msgKey, fullSize);
+	auto packet = _connection->prepareSecurePacket(_keyId, msgKey, fullSize);
 	const auto prefix = packet.size();
 	packet.resize(prefix + fullSize);
 
@@ -2600,7 +2607,7 @@ bool ConnectionPrivate::sendSecureRequest(
 	SHA256_Update(&msgKeyLargeContext, request->constData(), fullSize * sizeof(mtpPrime));
 	SHA256_Final(encryptedSHA256, &msgKeyLargeContext);
 
-	auto packet = _connection->prepareSecurePacket(keyId, msgKey, fullSize);
+	auto packet = _connection->prepareSecurePacket(_keyId, msgKey, fullSize);
 	const auto prefix = packet.size();
 	packet.resize(prefix + fullSize);
 
@@ -2627,8 +2634,8 @@ bool ConnectionPrivate::sendSecureRequest(
 mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 	if (msgId == _pingMsgId) return mtpRequestId(0xFFFFFFFF);
 	{
-		QReadLocker locker(sessionData->haveSentMutex());
-		const auto &haveSent = sessionData->haveSentMap();
+		QReadLocker locker(_sessionData->haveSentMutex());
+		const auto &haveSent = _sessionData->haveSentMap();
 		const auto i = haveSent.constFind(msgId);
 		if (i != haveSent.cend()) {
 			return i.value()->requestId
@@ -2637,14 +2644,14 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 		}
 	}
 	{
-		QReadLocker locker(sessionData->toResendMutex());
-		const auto &toResend = sessionData->toResendMap();
+		QReadLocker locker(_sessionData->toResendMutex());
+		const auto &toResend = _sessionData->toResendMap();
 		const auto i = toResend.constFind(msgId);
 		if (i != toResend.cend()) return i.value();
 	}
 	{
-		QReadLocker locker(sessionData->wereAckedMutex());
-		const auto &wereAcked = sessionData->wereAckedMap();
+		QReadLocker locker(_sessionData->wereAckedMutex());
+		const auto &wereAcked = _sessionData->wereAckedMap();
 		const auto i = wereAcked.constFind(msgId);
 		if (i != wereAcked.cend()) return i.value();
 	}
@@ -2653,14 +2660,14 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 
 void ConnectionPrivate::lockKey() {
 	unlockKey();
-	sessionData->keyMutex()->lockForWrite();
-	myKeyLock = true;
+	_sessionData->keyMutex()->lockForWrite();
+	_myKeyLock = true;
 }
 
 void ConnectionPrivate::unlockKey() {
-	if (myKeyLock) {
-		myKeyLock = false;
-		sessionData->keyMutex()->unlock();
+	if (_myKeyLock) {
+		_myKeyLock = false;
+		_sessionData->keyMutex()->unlock();
 	}
 }
 
@@ -2672,14 +2679,14 @@ ConnectionPrivate::~ConnectionPrivate() {
 }
 
 void ConnectionPrivate::stop() {
-	QWriteLocker lockFinished(&sessionDataMutex);
-	if (sessionData) {
-		if (myKeyLock) {
-			sessionData->owner()->notifyKeyCreated(AuthKeyPtr()); // release key lock, let someone else create it
-			sessionData->keyMutex()->unlock();
-			myKeyLock = false;
+	QWriteLocker lockFinished(&_sessionDataMutex);
+	if (_sessionData) {
+		if (_myKeyLock) {
+			_sessionData->owner()->notifyKeyCreated(AuthKeyPtr()); // release key lock, let someone else create it
+			_sessionData->keyMutex()->unlock();
+			_myKeyLock = false;
 		}
-		sessionData = nullptr;
+		_sessionData = nullptr;
 	}
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index e03a1815d..5d1c8f0a1 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -17,6 +17,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace MTP {
 namespace details {
 class DcKeyCreator;
+class DcKeyChecker;
 } // namespace details
 
 // How much time to wait for some more requests, when sending msg acks.
@@ -240,9 +241,10 @@ private:
 	base::Timer _waitForBetterTimer;
 	crl::time _waitForReceived = 0;
 	crl::time _waitForConnected = 0;
-	crl::time firstSentAt = -1;
+	crl::time _firstSentAt = -1;
 
-	QVector<MTPlong> ackRequestData, resendRequestData;
+	QVector<MTPlong> _ackRequestData;
+	QVector<MTPlong> _resendRequestData;
 
 	mtpPingId _pingId = 0;
 	mtpPingId _pingIdToSend = 0;
@@ -250,15 +252,15 @@ private:
 	mtpMsgId _pingMsgId = 0;
 	base::Timer _pingSender;
 
-	bool restarted = false;
+	bool _restarted = false;
 	bool _finished = false;
 
-	uint64 keyId = 0;
-	QReadWriteLock sessionDataMutex;
-	SessionData *sessionData = nullptr;
+	uint64 _keyId = 0;
+	QReadWriteLock _sessionDataMutex;
+	SessionData *_sessionData = nullptr;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 
-	bool myKeyLock = false;
+	bool _myKeyLock = false;
 
 	std::unique_ptr<details::DcKeyCreator> _keyCreator;
 
diff --git a/Telegram/SourceFiles/mtproto/core_types.h b/Telegram/SourceFiles/mtproto/core_types.h
index 3d666d038..bbf48680c 100644
--- a/Telegram/SourceFiles/mtproto/core_types.h
+++ b/Telegram/SourceFiles/mtproto/core_types.h
@@ -42,6 +42,7 @@ constexpr auto kLogoutDcShift = 0x02;
 constexpr auto kUpdaterDcShift = 0x03;
 constexpr auto kExportDcShift = 0x04;
 constexpr auto kExportMediaDcShift = 0x05;
+constexpr auto kCheckKeyDcShift = 0x06;
 constexpr auto kMaxMediaDcCount = 0x10;
 constexpr auto kBaseDownloadDcShift = 0x10;
 constexpr auto kBaseUploadDcShift = 0x20;
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index 1f12d81ac..60e03840d 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -69,8 +69,9 @@ struct ParsedPQ {
 	return { pStr, qStr };
 }
 
+template <typename PQInnerData>
 [[nodiscard]] bytes::vector EncryptPQInnerRSA(
-		const MTPP_Q_inner_data &data,
+		const PQInnerData &data,
 		const RSAPublicKey &key) {
 	constexpr auto kSkipPrimes = 6;
 	constexpr auto kMaxPrimes = 65; // 260 bytes
@@ -150,12 +151,15 @@ DcKeyCreator::DcKeyCreator(
 	int16 protocolDcId,
 	not_null<AbstractConnection*> connection,
 	not_null<DcOptions*> dcOptions,
-	Delegate delegate)
+	Delegate delegate,
+	TimeId expireIn)
 : _connection(connection)
 , _dcOptions(dcOptions)
 , _dcId(dcId)
 , _protocolDcId(protocolDcId)
+, _expireIn(expireIn)
 , _delegate(std::move(delegate)) {
+	Expects(_expireIn >= 0);
 	Expects(_delegate.done != nullptr);
 
 	_data.nonce = openssl::RandomValue<MTPint128>();
@@ -219,15 +223,30 @@ void DcKeyCreator::pqAnswered() {
 		return failed();
 	}
 
-	auto p_q_inner = MTP_p_q_inner_data_dc(
-		res_pq_data.vpq(),
-		MTP_bytes(parsed.p),
-		MTP_bytes(parsed.q),
-		_data.nonce,
-		_data.server_nonce,
-		_data.new_nonce,
-		MTP_int(_protocolDcId));
-	const auto dhEncString = EncryptPQInnerRSA(p_q_inner, rsaKey);
+	const auto dhEncString = [&] {
+		return (_expireIn == 0)
+			? EncryptPQInnerRSA(
+				MTP_p_q_inner_data_dc(
+					res_pq_data.vpq(),
+					MTP_bytes(parsed.p),
+					MTP_bytes(parsed.q),
+					_data.nonce,
+					_data.server_nonce,
+					_data.new_nonce,
+					MTP_int(_protocolDcId)),
+				rsaKey)
+			: EncryptPQInnerRSA(
+				MTP_p_q_inner_data_temp_dc(
+					res_pq_data.vpq(),
+					MTP_bytes(parsed.p),
+					MTP_bytes(parsed.q),
+					_data.nonce,
+					_data.server_nonce,
+					_data.new_nonce,
+					MTP_int(_protocolDcId),
+					MTP_int(_expireIn)),
+				rsaKey);
+	}();
 	if (dhEncString.empty()) {
 		return failed();
 	}
@@ -241,8 +260,8 @@ void DcKeyCreator::pqAnswered() {
 	sendNotSecureRequest(MTPReq_DH_params(
 		_data.nonce,
 		_data.server_nonce,
-		p_q_inner.c_p_q_inner_data_dc().vp(),
-		p_q_inner.c_p_q_inner_data_dc().vq(),
+		MTP_bytes(parsed.p),
+		MTP_bytes(parsed.q),
 		MTP_long(rsaKey.fingerprint()),
 		MTP_bytes(dhEncString)));
 }
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
index 6d774143b..2dfa2da86 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -42,7 +42,8 @@ public:
 		int16 protocolDcId,
 		not_null<AbstractConnection*> connection,
 		not_null<DcOptions*> dcOptions,
-		Delegate delegate);
+		Delegate delegate,
+		TimeId expireIn = 0); // 0 - persistent, > 0 - temporary
 	~DcKeyCreator();
 
 private:
@@ -87,8 +88,9 @@ private:
 
 	const not_null<AbstractConnection*> _connection;
 	const not_null<DcOptions*> _dcOptions;
-	const DcId _dcId;
+	const DcId _dcId = 0;
 	const int16 _protocolDcId = 0;
+	const TimeId _expireIn = 0;
 	Delegate _delegate;
 
 	Data _data;
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index f6f381f05..d6c182c09 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -64,13 +64,13 @@ ConnectionOptions::ConnectionOptions(
 
 void SessionData::setKey(const AuthKeyPtr &key) {
 	if (_authKey != key) {
-		uint64 session = rand_value<uint64>();
+		const auto sessionId = rand_value<uint64>();
 		_authKey = key;
 
-		DEBUG_LOG(("MTP Info: new auth key set in SessionData, id %1, setting random server_session %2").arg(key ? key->keyId() : 0).arg(session));
+		DEBUG_LOG(("MTP Info: new auth key set in SessionData, id %1, setting random server_session %2").arg(key ? key->keyId() : 0).arg(sessionId));
 		QWriteLocker locker(&_lock);
-		if (_session != session) {
-			_session = session;
+		if (_sessionId != sessionId) {
+			_sessionId = sessionId;
 			_messagesSent = 0;
 		}
 		_layerInited = false;
@@ -135,13 +135,14 @@ void SessionData::clear(Instance *instance) {
 	instance->clearCallbacksDelayed(std::move(clearCallbacks));
 }
 
-Session::Session(not_null<Instance*> instance, ShiftedDcId shiftedDcId) : QObject()
+Session::Session(not_null<Instance*> instance, ShiftedDcId shiftedDcId)
+: QObject()
 , _instance(instance)
-, data(this)
-, dcWithShift(shiftedDcId)
-, sender([=] { needToResumeAndSend(); }) {
-	connect(&timeouter, SIGNAL(timeout()), this, SLOT(checkRequestsByTimer()));
-	timeouter.start(1000);
+, _data(this)
+, _shiftedDcId(shiftedDcId)
+, _sender([=] { needToResumeAndSend(); }) {
+	connect(&_timeouter, SIGNAL(timeout()), this, SLOT(checkRequestsByTimer()));
+	_timeouter.start(1000);
 
 	refreshOptions();
 }
@@ -149,26 +150,26 @@ Session::Session(not_null<Instance*> instance, ShiftedDcId shiftedDcId) : QObjec
 void Session::start() {
 	createDcData();
 	_connection = std::make_unique<Connection>(_instance);
-	_connection->start(&data, dcWithShift);
+	_connection->start(&_data, _shiftedDcId);
 	if (_instance->isKeysDestroyer()) {
-		_instance->scheduleKeyDestroy(dcWithShift);
+		_instance->scheduleKeyDestroy(_shiftedDcId);
 	}
 }
 
 void Session::createDcData() {
-	if (dc) {
+	if (_dc) {
 		return;
 	}
-	dc = _instance->getDcById(dcWithShift);
+	_dc = _instance->getDcById(_shiftedDcId);
 
 	if (auto lock = ReadLockerAttempt(keyMutex())) {
-		data.setKey(dc->getKey());
-		if (dc->connectionInited()) {
-			data.setConnectionInited();
+		_data.setKey(_dc->getKey());
+		if (_dc->connectionInited()) {
+			_data.setConnectionInited();
 		}
 	}
-	connect(dc.get(), SIGNAL(authKeyCreated()), this, SLOT(authKeyCreatedForDC()), Qt::QueuedConnection);
-	connect(dc.get(), SIGNAL(connectionWasInited()), this, SLOT(connectionWasInitedForDC()), Qt::QueuedConnection);
+	connect(_dc.get(), SIGNAL(authKeyCreated()), this, SLOT(authKeyCreatedForDC()), Qt::QueuedConnection);
+	connect(_dc.get(), SIGNAL(connectionWasInited()), this, SLOT(connectionWasInitedForDC()), Qt::QueuedConnection);
 }
 
 bool Session::rpcErrorOccured(
@@ -197,7 +198,7 @@ void Session::refreshOptions() {
 	const auto useHttp = (proxyType != ProxyData::Type::Mtproto);
 	const auto useIPv4 = true;
 	const auto useIPv6 = Global::TryIPv6();
-	data.applyConnectionOptions(ConnectionOptions(
+	_data.applyConnectionOptions(ConnectionOptions(
 		_instance->systemLangCode(),
 		_instance->cloudLangCode(),
 		_instance->langPackName(),
@@ -211,8 +212,8 @@ void Session::refreshOptions() {
 }
 
 void Session::reInitConnection() {
-	dc->setConnectionInited(false);
-	data.setConnectionInited(false);
+	_dc->setConnectionInited(false);
+	_data.setConnectionInited(false);
 	restart();
 }
 
@@ -221,7 +222,7 @@ void Session::stop() {
 		DEBUG_LOG(("Session Error: can't kill a killed session"));
 		return;
 	}
-	DEBUG_LOG(("Session Info: stopping session dcWithShift %1").arg(dcWithShift));
+	DEBUG_LOG(("Session Info: stopping session dcWithShift %1").arg(_shiftedDcId));
 	if (_connection) {
 		_connection->kill();
 		_instance->queueQuittingConnection(std::move(_connection));
@@ -231,7 +232,7 @@ void Session::stop() {
 void Session::kill() {
 	stop();
 	_killed = true;
-	DEBUG_LOG(("Session Info: marked session dcWithShift %1 as killed").arg(dcWithShift));
+	DEBUG_LOG(("Session Info: marked session dcWithShift %1 as killed").arg(_shiftedDcId));
 }
 
 void Session::unpaused() {
@@ -246,27 +247,27 @@ void Session::sendAnything(qint64 msCanWait) {
 		DEBUG_LOG(("Session Error: can't send anything in a killed session"));
 		return;
 	}
-	auto ms = crl::now();
-	if (msSendCall) {
-		if (ms > msSendCall + msWait) {
-			msWait = 0;
+	const auto ms = crl::now();
+	if (_msSendCall) {
+		if (ms > _msSendCall + _msWait) {
+			_msWait = 0;
 		} else {
-			msWait = (msSendCall + msWait) - ms;
-			if (msWait > msCanWait) {
-				msWait = msCanWait;
+			_msWait = (_msSendCall + _msWait) - ms;
+			if (_msWait > msCanWait) {
+				_msWait = msCanWait;
 			}
 		}
 	} else {
-		msWait = msCanWait;
+		_msWait = msCanWait;
 	}
-	if (msWait) {
-		DEBUG_LOG(("MTP Info: dcWithShift %1 can wait for %2ms from current %3").arg(dcWithShift).arg(msWait).arg(msSendCall));
-		msSendCall = ms;
-		sender.callOnce(msWait);
+	if (_msWait) {
+		DEBUG_LOG(("MTP Info: dcWithShift %1 can wait for %2ms from current %3").arg(_shiftedDcId).arg(_msWait).arg(_msSendCall));
+		_msSendCall = ms;
+		_sender.callOnce(_msWait);
 	} else {
-		DEBUG_LOG(("MTP Info: dcWithShift %1 stopped send timer, can wait for %2ms from current %3").arg(dcWithShift).arg(msWait).arg(msSendCall));
-		sender.cancel();
-		msSendCall = 0;
+		DEBUG_LOG(("MTP Info: dcWithShift %1 stopped send timer, can wait for %2ms from current %3").arg(_shiftedDcId).arg(_msWait).arg(_msSendCall));
+		_sender.cancel();
+		_msSendCall = 0;
 		needToResumeAndSend();
 	}
 }
@@ -277,10 +278,10 @@ void Session::needToResumeAndSend() {
 		return;
 	}
 	if (!_connection) {
-		DEBUG_LOG(("Session Info: resuming session dcWithShift %1").arg(dcWithShift));
+		DEBUG_LOG(("Session Info: resuming session dcWithShift %1").arg(_shiftedDcId));
 		createDcData();
 		_connection = std::make_unique<Connection>(_instance);
-		_connection->start(&data, dcWithShift);
+		_connection->start(&_data, _shiftedDcId);
 	}
 	if (_ping) {
 		_ping = false;
@@ -292,7 +293,7 @@ void Session::needToResumeAndSend() {
 
 void Session::sendPong(quint64 msgId, quint64 pingId) {
 	_instance->sendProtocolMessage(
-		dcWithShift,
+		_shiftedDcId,
 		MTPPong(MTP_pong(MTP_long(msgId), MTP_long(pingId))));
 }
 
@@ -303,7 +304,7 @@ void Session::sendMsgsStateInfo(quint64 msgId, QByteArray data) {
 		bytes::copy(info, bytes::make_span(data));
 	}
 	_instance->sendProtocolMessage(
-		dcWithShift,
+		_shiftedDcId,
 		MTPMsgsStateInfo(
 			MTP_msgs_state_info(MTP_long(msgId), MTP_bytes(data))));
 }
@@ -314,8 +315,8 @@ void Session::checkRequestsByTimer() {
 	QVector<mtpMsgId> stateRequestIds;
 
 	{
-		QReadLocker locker(data.haveSentMutex());
-		auto &haveSent = data.haveSentMap();
+		QReadLocker locker(_data.haveSentMutex());
+		auto &haveSent = _data.haveSentMap();
 		const auto haveSentCount = haveSent.size();
 		auto ms = crl::now();
 		for (auto i = haveSent.begin(), e = haveSent.end(); i != e; ++i) {
@@ -342,9 +343,9 @@ void Session::checkRequestsByTimer() {
 	if (stateRequestIds.size()) {
 		DEBUG_LOG(("MTP Info: requesting state of msgs: %1").arg(LogIds(stateRequestIds)));
 		{
-			QWriteLocker locker(data.stateRequestMutex());
+			QWriteLocker locker(_data.stateRequestMutex());
 			for (uint32 i = 0, l = stateRequestIds.size(); i < l; ++i) {
-				data.stateRequestMap().insert(stateRequestIds[i], true);
+				_data.stateRequestMap().insert(stateRequestIds[i], true);
 			}
 		}
 		sendAnything(kCheckResendWaiting);
@@ -358,8 +359,8 @@ void Session::checkRequestsByTimer() {
 	if (!removingIds.isEmpty()) {
 		auto clearCallbacks = std::vector<RPCCallbackClear>();
 		{
-			QWriteLocker locker(data.haveSentMutex());
-			auto &haveSent = data.haveSentMap();
+			QWriteLocker locker(_data.haveSentMutex());
+			auto &haveSent = _data.haveSentMap();
 			for (uint32 i = 0, l = removingIds.size(); i < l; ++i) {
 				auto j = haveSent.find(removingIds[i]);
 				if (j != haveSent.cend()) {
@@ -375,21 +376,21 @@ void Session::checkRequestsByTimer() {
 }
 
 void Session::onConnectionStateChange(qint32 newState) {
-	_instance->onStateChange(dcWithShift, newState);
+	_instance->onStateChange(_shiftedDcId, newState);
 }
 
 void Session::onResetDone() {
-	_instance->onSessionReset(dcWithShift);
+	_instance->onSessionReset(_shiftedDcId);
 }
 
 void Session::cancel(mtpRequestId requestId, mtpMsgId msgId) {
 	if (requestId) {
-		QWriteLocker locker(data.toSendMutex());
-		data.toSendMap().remove(requestId);
+		QWriteLocker locker(_data.toSendMutex());
+		_data.toSendMap().remove(requestId);
 	}
 	if (msgId) {
-		QWriteLocker locker(data.haveSentMutex());
-		data.haveSentMap().remove(msgId);
+		QWriteLocker locker(_data.haveSentMutex());
+		_data.haveSentMap().remove(msgId);
 	}
 }
 
@@ -421,8 +422,8 @@ int32 Session::requestState(mtpRequestId requestId) const {
 	}
 	if (!requestId) return MTP::RequestSent;
 
-	QWriteLocker locker(data.toSendMutex());
-	const auto &toSend = data.toSendMap();
+	QWriteLocker locker(_data.toSendMutex());
+	const auto &toSend = _data.toSendMap();
 	const auto i = toSend.constFind(requestId);
 	if (i != toSend.cend()) {
 		return MTP::RequestSending;
@@ -461,8 +462,8 @@ QString Session::transport() const {
 mtpRequestId Session::resend(quint64 msgId, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo) {
 	SecureRequest request;
 	{
-		QWriteLocker locker(data.haveSentMutex());
-		auto &haveSent = data.haveSentMap();
+		QWriteLocker locker(_data.haveSentMutex());
+		auto &haveSent = _data.haveSentMap();
 
 		auto i = haveSent.find(msgId);
 		if (i == haveSent.end()) {
@@ -472,7 +473,7 @@ mtpRequestId Session::resend(quint64 msgId, qint64 msCanWait, bool forceContaine
 
 				auto info = std::string(cantResend, cantResend + 1);
 				return _instance->sendProtocolMessage(
-					dcWithShift,
+					_shiftedDcId,
 					MTPMsgsStateInfo(
 						MTP_msgs_state_info(
 							MTP_long(msgId),
@@ -495,8 +496,8 @@ mtpRequestId Session::resend(quint64 msgId, qint64 msCanWait, bool forceContaine
 		request->msDate = forceContainer ? 0 : crl::now();
 		sendPrepared(request, msCanWait, false);
 		{
-			QWriteLocker locker(data.toResendMutex());
-			data.toResendMap().insert(msgId, request->requestId);
+			QWriteLocker locker(_data.toResendMutex());
+			_data.toResendMap().insert(msgId, request->requestId);
 		}
 		return request->requestId;
 	} else {
@@ -513,8 +514,8 @@ void Session::resendMany(QVector<quint64> msgIds, qint64 msCanWait, bool forceCo
 void Session::resendAll() {
 	QVector<mtpMsgId> toResend;
 	{
-		QReadLocker locker(data.haveSentMutex());
-		const auto &haveSent = data.haveSentMap();
+		QReadLocker locker(_data.haveSentMutex());
+		const auto &haveSent = _data.haveSentMap();
 		toResend.reserve(haveSent.size());
 		for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
 			if (i.value()->requestId) {
@@ -534,8 +535,8 @@ void Session::sendPrepared(
 	DEBUG_LOG(("MTP Info: adding request to toSendMap, msCanWait %1"
 		).arg(msCanWait));
 	{
-		QWriteLocker locker(data.toSendMutex());
-		data.toSendMap().insert(request->requestId, request);
+		QWriteLocker locker(_data.toSendMutex());
+		_data.toSendMap().insert(request->requestId, request);
 
 		if (newRequest) {
 			*(mtpMsgId*)(request->data() + 4) = 0;
@@ -549,45 +550,47 @@ void Session::sendPrepared(
 }
 
 QReadWriteLock *Session::keyMutex() const {
-	return dc->keyMutex();
+	return _dc->keyMutex();
 }
 
 void Session::authKeyCreatedForDC() {
-	DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, emitting authKeyCreated(), dcWithShift %1").arg(dcWithShift));
-	data.setKey(dc->getKey());
+	DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, emitting authKeyCreated(), dcWithShift %1").arg(_shiftedDcId));
+	_data.setKey(_dc->getKey());
 	emit authKeyCreated();
 }
 
 void Session::notifyKeyCreated(AuthKeyPtr &&key) {
-	DEBUG_LOG(("AuthKey Info: Session::keyCreated(), setting, dcWithShift %1").arg(dcWithShift));
-	dc->setKey(std::move(key));
+	DEBUG_LOG(("AuthKey Info: Session::keyCreated(), setting, dcWithShift %1").arg(_shiftedDcId));
+	_dc->setKey(std::move(key));
 }
 
 void Session::connectionWasInitedForDC() {
-	DEBUG_LOG(("MTP Info: Session::connectionWasInitedForDC slot, dcWithShift %1").arg(dcWithShift));
-	data.setConnectionInited();
+	DEBUG_LOG(("MTP Info: Session::connectionWasInitedForDC slot, dcWithShift %1").arg(_shiftedDcId));
+	_data.setConnectionInited();
 }
 
 void Session::notifyDcConnectionInited() {
-	DEBUG_LOG(("MTP Info: emitting MTProtoDC::connectionWasInited(), dcWithShift %1").arg(dcWithShift));
-	dc->setConnectionInited();
-	emit dc->connectionWasInited();
+	DEBUG_LOG(("MTP Info: emitting MTProtoDC::connectionWasInited(), dcWithShift %1").arg(_shiftedDcId));
+	_dc->setConnectionInited();
+	emit _dc->connectionWasInited();
 }
 
 void Session::destroyKey() {
-	if (!dc) return;
+	if (!_dc) {
+		return;
+	}
 
-	if (data.getKey()) {
-		DEBUG_LOG(("MTP Info: destroying auth_key for dcWithShift %1").arg(dcWithShift));
-		if (data.getKey() == dc->getKey()) {
-			dc->destroyKey();
+	if (_data.getKey()) {
+		DEBUG_LOG(("MTP Info: destroying auth_key for dcWithShift %1").arg(_shiftedDcId));
+		if (_data.getKey() == _dc->getKey()) {
+			_dc->destroyKey();
 		}
-		data.setKey(AuthKeyPtr());
+		_data.setKey(AuthKeyPtr());
 	}
 }
 
 int32 Session::getDcWithShift() const {
-	return dcWithShift;
+	return _shiftedDcId;
 }
 
 void Session::tryToReceive() {
@@ -604,11 +607,11 @@ void Session::tryToReceive() {
 		auto isUpdate = false;
 		auto message = SerializedMessage();
 		{
-			QWriteLocker locker(data.haveReceivedMutex());
-			auto &responses = data.haveReceivedResponses();
+			QWriteLocker locker(_data.haveReceivedMutex());
+			auto &responses = _data.haveReceivedResponses();
 			auto response = responses.begin();
 			if (response == responses.cend()) {
-				auto &updates = data.haveReceivedUpdates();
+				auto &updates = _data.haveReceivedUpdates();
 				auto update = updates.begin();
 				if (update == updates.cend()) {
 					return;
@@ -624,7 +627,7 @@ void Session::tryToReceive() {
 			}
 		}
 		if (isUpdate) {
-			if (dcWithShift == BareDcId(dcWithShift)) { // call globalCallback only in main session
+			if (_shiftedDcId == BareDcId(_shiftedDcId)) { // call globalCallback only in main session
 				_instance->globalCallback(message.constData(), message.constData() + message.size());
 			}
 		} else {
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index a08315852..f53a356fe 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -141,18 +141,18 @@ public:
 	SessionData(not_null<Session*> creator) : _owner(creator) {
 	}
 
-	void setSession(uint64 session) {
-		DEBUG_LOG(("MTP Info: setting server_session: %1").arg(session));
+	void setSessionId(uint64 sessionId) {
+		DEBUG_LOG(("MTP Info: setting server_session: %1").arg(sessionId));
 
 		QWriteLocker locker(&_lock);
-		if (_session != session) {
-			_session = session;
+		if (_sessionId != sessionId) {
+			_sessionId = sessionId;
 			_messagesSent = 0;
 		}
 	}
-	uint64 getSession() const {
+	uint64 getSessionId() const {
 		QReadLocker locker(&_lock);
-		return _session;
+		return _sessionId;
 	}
 	void setConnectionInited(bool inited = true) {
 		QWriteLocker locker(&_lock);
@@ -283,7 +283,7 @@ public:
 	void clear(Instance *instance);
 
 private:
-	uint64 _session = 0;
+	uint64 _sessionId = 0;
 	uint64 _salt = 0;
 
 	uint32 _messagesSent = 0;
@@ -389,18 +389,18 @@ private:
 	bool _killed = false;
 	bool _needToReceive = false;
 
-	SessionData data;
+	SessionData _data;
 
-	ShiftedDcId dcWithShift = 0;
-	std::shared_ptr<Dcenter> dc;
+	ShiftedDcId _shiftedDcId = 0;
+	std::shared_ptr<Dcenter> _dc;
 
-	crl::time msSendCall = 0;
-	crl::time msWait = 0;
+	crl::time _msSendCall = 0;
+	crl::time _msWait = 0;
 
 	bool _ping = false;
 
-	QTimer timeouter;
-	base::Timer sender;
+	QTimer _timeouter;
+	base::Timer _sender;
 
 };
 

From 7243fb52ad5c6b6158b580739519f6e04bbfd6de Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 14 Nov 2019 16:34:58 +0300
Subject: [PATCH 10/91] Check keys that receive -404 error codes.

---
 Telegram/SourceFiles/core/utils.h             |  29 ---
 Telegram/SourceFiles/mtproto/auth_key.cpp     |  11 ++
 Telegram/SourceFiles/mtproto/auth_key.h       |  16 +-
 Telegram/SourceFiles/mtproto/connection.cpp   | 176 +++++++++++-------
 Telegram/SourceFiles/mtproto/connection.h     |   1 +
 Telegram/SourceFiles/mtproto/core_types.cpp   |  58 ++++--
 Telegram/SourceFiles/mtproto/core_types.h     |  20 +-
 Telegram/SourceFiles/mtproto/dcenter.h        |   5 +
 .../details/mtproto_dc_key_checker.cpp        | 135 +++++++++++++-
 .../mtproto/details/mtproto_dc_key_checker.h  |  23 ++-
 .../details/mtproto_dc_key_creator.cpp        |  11 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  44 ++++-
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   2 +
 Telegram/SourceFiles/mtproto/session.cpp      |  46 +++--
 Telegram/SourceFiles/mtproto/session.h        |  42 ++++-
 15 files changed, 460 insertions(+), 159 deletions(-)

diff --git a/Telegram/SourceFiles/core/utils.h b/Telegram/SourceFiles/core/utils.h
index 9a21cabce..1fb36a8c9 100644
--- a/Telegram/SourceFiles/core/utils.h
+++ b/Telegram/SourceFiles/core/utils.h
@@ -167,35 +167,6 @@ T rand_value() {
 	return result;
 }
 
-class ReadLockerAttempt {
-public:
-	ReadLockerAttempt(not_null<QReadWriteLock*> lock) : _lock(lock), _locked(_lock->tryLockForRead()) {
-	}
-	ReadLockerAttempt(const ReadLockerAttempt &other) = delete;
-	ReadLockerAttempt &operator=(const ReadLockerAttempt &other) = delete;
-	ReadLockerAttempt(ReadLockerAttempt &&other) : _lock(other._lock), _locked(base::take(other._locked)) {
-	}
-	ReadLockerAttempt &operator=(ReadLockerAttempt &&other) {
-		_lock = other._lock;
-		_locked = base::take(other._locked);
-		return *this;
-	}
-	~ReadLockerAttempt() {
-		if (_locked) {
-			_lock->unlock();
-		}
-	}
-
-	operator bool() const {
-		return _locked;
-	}
-
-private:
-	not_null<QReadWriteLock*> _lock;
-	bool _locked = false;
-
-};
-
 static const QRegularExpression::PatternOptions reMultiline(QRegularExpression::DotMatchesEverythingOption | QRegularExpression::MultilineOption);
 
 template <typename T>
diff --git a/Telegram/SourceFiles/mtproto/auth_key.cpp b/Telegram/SourceFiles/mtproto/auth_key.cpp
index f116a707b..6df7761c3 100644
--- a/Telegram/SourceFiles/mtproto/auth_key.cpp
+++ b/Telegram/SourceFiles/mtproto/auth_key.cpp
@@ -19,6 +19,9 @@ AuthKey::AuthKey(Type type, DcId dcId, const Data &data)
 , _dcId(dcId)
 , _key(data) {
 	countKeyId();
+	if (type == Type::Generated) {
+		_lastCheckTime = crl::now();
+	}
 }
 
 AuthKey::AuthKey(const Data &data) : _type(Type::Local), _key(data) {
@@ -111,6 +114,14 @@ bool AuthKey::equals(const std::shared_ptr<AuthKey> &other) const {
 	return other ? (_key == other->_key) : false;
 }
 
+crl::time AuthKey::lastCheckTime() const {
+	return _lastCheckTime;
+}
+
+void AuthKey::setLastCheckTime(crl::time time) {
+	_lastCheckTime = time;
+}
+
 void AuthKey::FillData(Data &authKey, bytes::const_span computedAuthKey) {
 	auto computedAuthKeySize = computedAuthKey.size();
 	Assert(computedAuthKeySize <= kSize);
diff --git a/Telegram/SourceFiles/mtproto/auth_key.h b/Telegram/SourceFiles/mtproto/auth_key.h
index dcfae3244..7120cfa48 100644
--- a/Telegram/SourceFiles/mtproto/auth_key.h
+++ b/Telegram/SourceFiles/mtproto/auth_key.h
@@ -30,18 +30,21 @@ public:
 	AuthKey(const AuthKey &other) = delete;
 	AuthKey &operator=(const AuthKey &other) = delete;
 
-	Type type() const;
-	int dcId() const;
-	KeyId keyId() const;
+	[[nodiscard]] Type type() const;
+	[[nodiscard]] int dcId() const;
+	[[nodiscard]] KeyId keyId() const;
 
 	void prepareAES_oldmtp(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const;
 	void prepareAES(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const;
 
-	const void *partForMsgKey(bool send) const;
+	[[nodiscard]] const void *partForMsgKey(bool send) const;
 
 	void write(QDataStream &to) const;
-	bytes::const_span data() const;
-	bool equals(const std::shared_ptr<AuthKey> &other) const;
+	[[nodiscard]] bytes::const_span data() const;
+	[[nodiscard]] bool equals(const std::shared_ptr<AuthKey> &other) const;
+
+	[[nodiscard]] crl::time lastCheckTime() const;
+	void setLastCheckTime(crl::time time);
 
 	static void FillData(Data &authKey, bytes::const_span computedAuthKey);
 
@@ -52,6 +55,7 @@ private:
 	DcId _dcId = 0;
 	Data _key = { { gsl::byte{} } };
 	KeyId _keyId = 0;
+	crl::time _lastCheckTime = 0;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 318330699..38b902067 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/connection.h"
 
 #include "mtproto/details/mtproto_dc_key_creator.h"
+#include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/session.h"
 #include "mtproto/rsa_public_key.h"
 #include "mtproto/rpc_sender.h"
@@ -94,7 +95,8 @@ void wrapInvokeAfter(SecureRequest &to, const SecureRequest &from, const Request
 
 } // namespace
 
-Connection::Connection(not_null<Instance*> instance) : _instance(instance) {
+Connection::Connection(not_null<Instance*> instance)
+: _instance(instance) {
 }
 
 void Connection::start(SessionData *sessionData, ShiftedDcId shiftedDcId) {
@@ -457,27 +459,31 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 	emit sessionResetDone();
 }
 
-mtpMsgId ConnectionPrivate::prepareToSend(SecureRequest &request, mtpMsgId currentLastId) {
-	if (request->size() < 9) return 0;
-	mtpMsgId msgId = *(mtpMsgId*)(request->constData() + 4);
-	if (msgId) { // resending this request
+mtpMsgId ConnectionPrivate::prepareToSend(
+		SecureRequest &request,
+		mtpMsgId currentLastId) {
+	if (request->size() < 9) {
+		return 0;
+	}
+	if (const auto msgId = request.getMsgId()) {
+		// resending this request
 		QWriteLocker locker(_sessionData->toResendMutex());
 		auto &toResend = _sessionData->toResendMap();
 		const auto i = toResend.find(msgId);
 		if (i != toResend.cend()) {
 			toResend.erase(i);
 		}
-	} else {
-		msgId = *(mtpMsgId*)(request->data() + 4) = currentLastId;
-		*(request->data() + 6) = _sessionData->nextRequestSeqNumber(request.needAck());
+		return msgId;
 	}
-	return msgId;
+	request.setMsgId(currentLastId);
+	request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
+	return currentLastId;
 }
 
 mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId) {
 	if (request->size() < 9) return 0;
 
-	mtpMsgId oldMsgId = *(mtpMsgId*)(request->constData() + 4);
+	const auto oldMsgId = request.getMsgId();
 	if (oldMsgId != newId) {
 		if (oldMsgId) {
 			QWriteLocker locker(_sessionData->toResendMutex());
@@ -530,9 +536,9 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 				}
 			}
 		} else {
-			*(request->data() + 6) = _sessionData->nextRequestSeqNumber(request.needAck());
+			request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
 		}
-		*(mtpMsgId*)(request->data() + 4) = newId;
+		request.setMsgId(newId);
 	}
 	return newId;
 }
@@ -562,15 +568,25 @@ void ConnectionPrivate::tryToSend() {
 
 	auto needsLayer = !_connectionOptions->inited;
 	auto state = getState();
-	auto prependOnly = (state != ConnectedState);
+	auto sendOnlyFirstPing = (state != ConnectedState);
+	if (sendOnlyFirstPing && !_pingIdToSend) {
+		DEBUG_LOG(("MTP Info: dc %1 not sending, waiting for Connected state, state: %2").arg(_shiftedDcId).arg(state));
+		return; // just do nothing, if is not connected yet
+	}
+
 	auto pingRequest = SecureRequest();
+	auto ackRequest = SecureRequest();
+	auto resendRequest = SecureRequest();
+	auto stateRequest = SecureRequest();
+	auto httpWaitRequest = SecureRequest();
+	auto checkDcKeyRequest = SecureRequest();
 	if (_shiftedDcId == BareDcId(_shiftedDcId)) { // main session
-		if (!prependOnly && !_pingIdToSend && !_pingId && _pingSendAt <= crl::now()) {
+		if (!sendOnlyFirstPing && !_pingIdToSend && !_pingId && _pingSendAt <= crl::now()) {
 			_pingIdToSend = rand_value<mtpPingId>();
 		}
 	}
 	if (_pingIdToSend) {
-		if (prependOnly || _shiftedDcId != BareDcId(_shiftedDcId)) {
+		if (sendOnlyFirstPing || _shiftedDcId != BareDcId(_shiftedDcId)) {
 			pingRequest = SecureRequest::Serialize(MTPPing(
 				MTP_long(_pingIdToSend)
 			));
@@ -584,44 +600,28 @@ void ConnectionPrivate::tryToSend() {
 				"ping_id: %1").arg(_pingIdToSend));
 		}
 
-		pingRequest->msDate = crl::now(); // > 0 - can send without container
 		_pingSendAt = pingRequest->msDate + kPingSendAfter;
-		pingRequest->requestId = 0; // dont add to haveSent / wereAcked maps
-
-		if (_shiftedDcId == BareDcId(_shiftedDcId) && !prependOnly) { // main session
+		if (_shiftedDcId == BareDcId(_shiftedDcId) && !sendOnlyFirstPing) { // main session
 			_pingSender.callOnce(kPingSendAfterForce);
 		}
-
-		_pingId = _pingIdToSend;
-		_pingIdToSend = 0;
+		_pingId = base::take(_pingIdToSend);
 	} else {
-		if (prependOnly) {
-			DEBUG_LOG(("MTP Info: dc %1 not sending, waiting for Connected state, state: %2").arg(_shiftedDcId).arg(state));
-			return; // just do nothing, if is not connected yet
-		} else {
-			DEBUG_LOG(("MTP Info: dc %1 trying to send after ping, state: %2").arg(_shiftedDcId).arg(state));
+		DEBUG_LOG(("MTP Info: dc %1 trying to send after ping, state: %2").arg(_shiftedDcId).arg(state));
+	}
+
+	if (!sendOnlyFirstPing) {
+		if (!_ackRequestData.isEmpty()) {
+			ackRequest = SecureRequest::Serialize(MTPMsgsAck(
+				MTP_msgs_ack(MTP_vector<MTPlong>(
+					base::take(_ackRequestData)))));
+		}
+		if (!_resendRequestData.isEmpty()) {
+			resendRequest = SecureRequest::Serialize(MTPMsgResendReq(
+				MTP_msg_resend_req(MTP_vector<MTPlong>(
+					base::take(_resendRequestData)))));
 		}
-	}
 
-	SecureRequest ackRequest, resendRequest, stateRequest, httpWaitRequest;
-	if (!prependOnly && !_ackRequestData.isEmpty()) {
-		ackRequest = SecureRequest::Serialize(MTPMsgsAck(
-			MTP_msgs_ack(MTP_vector<MTPlong>(_ackRequestData))));
-		ackRequest->msDate = crl::now(); // > 0 - can send without container
-		ackRequest->requestId = 0; // dont add to haveSent / wereAcked maps
-
-		_ackRequestData.clear();
-	}
-	if (!prependOnly && !_resendRequestData.isEmpty()) {
-		resendRequest = SecureRequest::Serialize(MTPMsgResendReq(
-			MTP_msg_resend_req(MTP_vector<MTPlong>(_resendRequestData))));
-		resendRequest->msDate = crl::now(); // > 0 - can send without container
-		resendRequest->requestId = 0; // dont add to haveSent / wereAcked maps
-
-		_resendRequestData.clear();
-	}
-	if (!prependOnly) {
-		QVector<MTPlong> stateReq;
+		auto stateReq = QVector<MTPlong>();
 		{
 			QWriteLocker locker(_sessionData->stateRequestMutex());
 			auto &ids = _sessionData->stateRequestMap();
@@ -636,14 +636,30 @@ void ConnectionPrivate::tryToSend() {
 		if (!stateReq.isEmpty()) {
 			stateRequest = SecureRequest::Serialize(MTPMsgsStateReq(
 				MTP_msgs_state_req(MTP_vector<MTPlong>(stateReq))));
-			stateRequest->msDate = crl::now(); // > 0 - can send without container
-			stateRequest->requestId = GetNextRequestId();// add to haveSent / wereAcked maps, but don't add to requestMap
+			// Add to haveSent / wereAcked maps, but don't add to requestMap.
+			stateRequest->requestId = GetNextRequestId();
 		}
 		if (_connection->usingHttpWait()) {
 			httpWaitRequest = SecureRequest::Serialize(MTPHttpWait(
 				MTP_http_wait(MTP_int(100), MTP_int(30), MTP_int(25000))));
-			httpWaitRequest->msDate = crl::now(); // > 0 - can send without container
-			httpWaitRequest->requestId = 0; // dont add to haveSent / wereAcked maps
+		}
+		if (!_keyChecker) {
+			if (const auto &keyForCheck = _sessionData->getKeyForCheck()) {
+				_keyChecker = std::make_unique<details::DcKeyChecker>(
+					_instance,
+					_shiftedDcId,
+					keyForCheck);
+				checkDcKeyRequest = _keyChecker->prepareRequest(
+					_sessionData->getKey(),
+					_sessionData->getSessionId());
+
+				// This is a special request with msgId used inside the message
+				// body, so it is prepared already with a msgId and we place
+				// seqNo for it manually here.
+				checkDcKeyRequest.setSeqNo(
+					_sessionData->nextRequestSeqNumber(
+						checkDcKeyRequest.needAck()));
+			}
 		}
 	}
 
@@ -698,8 +714,12 @@ void ConnectionPrivate::tryToSend() {
 		QWriteLocker locker1(_sessionData->toSendMutex());
 
 		auto toSendDummy = PreRequestMap();
-		auto &toSend = prependOnly ? toSendDummy : _sessionData->toSendMap();
-		if (prependOnly) locker1.unlock();
+		auto &toSend = sendOnlyFirstPing
+			? toSendDummy
+			: _sessionData->toSendMap();
+		if (sendOnlyFirstPing) {
+			locker1.unlock();
+		}
 
 		uint32 toSendCount = toSend.size();
 		if (pingRequest) ++toSendCount;
@@ -707,13 +727,28 @@ void ConnectionPrivate::tryToSend() {
 		if (resendRequest) ++toSendCount;
 		if (stateRequest) ++toSendCount;
 		if (httpWaitRequest) ++toSendCount;
+		if (checkDcKeyRequest) ++toSendCount;
 
-		if (!toSendCount) return; // nothing to send
+		if (!toSendCount) {
+			return; // nothing to send
+		}
 
-		auto first = pingRequest ? pingRequest : (ackRequest ? ackRequest : (resendRequest ? resendRequest : (stateRequest ? stateRequest : (httpWaitRequest ? httpWaitRequest : toSend.cbegin().value()))));
+		const auto first = pingRequest
+			? pingRequest
+			: ackRequest
+			? ackRequest
+			: resendRequest
+			? resendRequest
+			: stateRequest
+			? stateRequest
+			: httpWaitRequest
+			? httpWaitRequest
+			: checkDcKeyRequest
+			? checkDcKeyRequest
+			: toSend.cbegin().value();
 		if (toSendCount == 1 && first->msDate > 0) { // if can send without container
 			toSendRequest = first;
-			if (!prependOnly) {
+			if (!sendOnlyFirstPing) {
 				toSend.clear();
 				locker1.unlock();
 			}
@@ -774,6 +809,7 @@ void ConnectionPrivate::tryToSend() {
 			if (resendRequest) containerSize += resendRequest.messageSize();
 			if (stateRequest) containerSize += stateRequest.messageSize();
 			if (httpWaitRequest) containerSize += httpWaitRequest.messageSize();
+			if (checkDcKeyRequest) containerSize += checkDcKeyRequest.messageSize();
 			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
 				containerSize += i.value().messageSize();
 				if (needsLayer && i.value()->needsLayer) {
@@ -815,7 +851,7 @@ void ConnectionPrivate::tryToSend() {
 			if (pingRequest) {
 				_pingMsgId = placeToContainer(toSendRequest, bigMsgId, haveSentArr, pingRequest);
 				needAnyResponse = true;
-			} else if (resendRequest || stateRequest) {
+			} else if (resendRequest || stateRequest || checkDcKeyRequest) {
 				needAnyResponse = true;
 			}
 			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
@@ -869,6 +905,7 @@ void ConnectionPrivate::tryToSend() {
 			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, resendRequest);
 			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, ackRequest);
 			if (httpWaitRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, httpWaitRequest);
+			if (checkDcKeyRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, checkDcKeyRequest);
 
 			mtpMsgId contMsgId = prepareToSend(toSendRequest, bigMsgId);
 			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = contMsgId;
@@ -1945,6 +1982,9 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			}
 		}
 
+		if (_keyChecker && _keyChecker->handleResponse(reqMsgId, response)) {
+			return HandleResult::Success;
+		}
 		auto requestId = wasSent(reqMsgId.v);
 		if (requestId && requestId != mtpRequestId(0xFFFFFFFF)) {
 			// Save rpc_result for processing in the main thread.
@@ -2437,7 +2477,8 @@ void ConnectionPrivate::createDcKey() {
 
 			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(authKey->keyId()).arg(result->serverSalt));
 
-			_sessionData->owner()->notifyKeyCreated(std::move(authKey)); // slot will call authKeyCreated()
+			// slot will call authKeyCreated().
+			_sessionData->owner()->notifyKeyCreated(std::move(authKey));
 			_sessionData->clear(_instance);
 			unlockKey();
 		} else if (result.error() == Error::UnknownPublicKey) {
@@ -2539,7 +2580,13 @@ bool ConnectionPrivate::sendSecureRequest(
 		SecureRequest &&request,
 		bool needAnyResponse,
 		QReadLocker &lockFinished) {
-	request.addPadding(_connection->requiresExtendedPadding());
+#ifdef TDESKTOP_MTPROTO_OLD
+	const auto oldPadding = true;
+#else // TDESKTOP_MTPROTO_OLD
+	const auto oldPadding = false;
+#endif // TDESKTOP_MTPROTO_OLD
+	request.addPadding(_connection->requiresExtendedPadding(), oldPadding);
+
 	uint32 fullSize = request->size();
 	if (fullSize < 9) {
 		return false;
@@ -2660,14 +2707,18 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 
 void ConnectionPrivate::lockKey() {
 	unlockKey();
-	_sessionData->keyMutex()->lockForWrite();
+	if (const auto mutex = _sessionData->keyMutex()) {
+		mutex->lockForWrite();
+	}
 	_myKeyLock = true;
 }
 
 void ConnectionPrivate::unlockKey() {
 	if (_myKeyLock) {
 		_myKeyLock = false;
-		_sessionData->keyMutex()->unlock();
+		if (const auto mutex = _sessionData->keyMutex()) {
+			mutex->unlock();
+		}
 	}
 }
 
@@ -2683,8 +2734,7 @@ void ConnectionPrivate::stop() {
 	if (_sessionData) {
 		if (_myKeyLock) {
 			_sessionData->owner()->notifyKeyCreated(AuthKeyPtr()); // release key lock, let someone else create it
-			_sessionData->keyMutex()->unlock();
-			_myKeyLock = false;
+			unlockKey();
 		}
 		_sessionData = nullptr;
 	}
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 5d1c8f0a1..337525e6b 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -263,6 +263,7 @@ private:
 	bool _myKeyLock = false;
 
 	std::unique_ptr<details::DcKeyCreator> _keyCreator;
+	std::unique_ptr<details::DcKeyChecker> _keyChecker;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/core_types.cpp b/Telegram/SourceFiles/mtproto/core_types.cpp
index 7a5a8bc1f..12b250919 100644
--- a/Telegram/SourceFiles/mtproto/core_types.cpp
+++ b/Telegram/SourceFiles/mtproto/core_types.cpp
@@ -12,12 +12,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace MTP {
 namespace {
 
-uint32 CountPaddingAmountInInts(uint32 requestSize, bool extended) {
-#ifdef TDESKTOP_MTPROTO_OLD
-	return ((8 + requestSize) & 0x03)
-		? (4 - ((8 + requestSize) & 0x03))
-		: 0;
-#else // TDESKTOP_MTPROTO_OLD
+uint32 CountPaddingPrimesCount(uint32 requestSize, bool extended, bool old) {
+	if (old) {
+		return ((8 + requestSize) & 0x03)
+			? (4 - ((8 + requestSize) & 0x03))
+			: 0;
+	}
 	auto result = ((8 + requestSize) & 0x03)
 		? (4 - ((8 + requestSize) & 0x03))
 		: 0;
@@ -33,7 +33,6 @@ uint32 CountPaddingAmountInInts(uint32 requestSize, bool extended) {
 	}
 
 	return result;
-#endif // TDESKTOP_MTPROTO_OLD
 }
 
 } // namespace
@@ -49,6 +48,7 @@ SecureRequest SecureRequest::Prepare(uint32 size, uint32 reserveSize) {
 	result->reserve(kMessageBodyPosition + finalSize);
 	result->resize(kMessageBodyPosition);
 	result->back() = (size << 2);
+	result->msDate = crl::now(); // > 0 - can send without container
 	return result;
 }
 
@@ -68,11 +68,39 @@ SecureRequest::operator bool() const {
 	return (_data != nullptr);
 }
 
-void SecureRequest::addPadding(bool extended) {
-	if (_data->size() <= kMessageBodyPosition) return;
+void SecureRequest::setMsgId(mtpMsgId msgId) {
+	Expects(_data != nullptr);
+
+	memcpy(_data->data() + kMessageIdPosition, &msgId, sizeof(mtpMsgId));
+}
+
+mtpMsgId SecureRequest::getMsgId() const {
+	Expects(_data != nullptr);
+
+	return *(mtpMsgId*)(_data->constData() + kMessageIdPosition);
+}
+
+void SecureRequest::setSeqNo(uint32 seqNo) {
+	Expects(_data != nullptr);
+
+	(*_data)[kSeqNoPosition] = mtpPrime(seqNo);
+}
+
+uint32 SecureRequest::getSeqNo() const {
+	Expects(_data != nullptr);
+
+	return uint32((*_data)[kSeqNoPosition]);
+}
+
+void SecureRequest::addPadding(bool extended, bool old) {
+	Expects(_data != nullptr);
+
+	if (_data->size() <= kMessageBodyPosition) {
+		return;
+	}
 
 	const auto requestSize = (tl::count_length(*this) >> 2);
-	const auto padding = CountPaddingAmountInInts(requestSize, extended);
+	const auto padding = CountPaddingPrimesCount(requestSize, extended, old);
 	const auto fullSize = kMessageBodyPosition + requestSize + padding;
 	if (uint32(_data->size()) != fullSize) {
 		_data->resize(fullSize);
@@ -85,6 +113,8 @@ void SecureRequest::addPadding(bool extended) {
 }
 
 uint32 SecureRequest::messageSize() const {
+	Expects(_data != nullptr);
+
 	if (_data->size() <= kMessageBodyPosition) {
 		return 0;
 	}
@@ -93,13 +123,17 @@ uint32 SecureRequest::messageSize() const {
 }
 
 bool SecureRequest::isSentContainer() const {
+	Expects(_data != nullptr);
+
 	if (_data->size() <= kMessageBodyPosition) {
 		return false;
 	}
-	return (!_data->msDate && !(*_data)[kSeqNoPosition]); // msDate = 0, seqNo = 0
+	return (!_data->msDate && !getSeqNo()); // msDate = 0, seqNo = 0
 }
 
 bool SecureRequest::isStateRequest() const {
+	Expects(_data != nullptr);
+
 	if (_data->size() <= kMessageBodyPosition) {
 		return false;
 	}
@@ -108,6 +142,8 @@ bool SecureRequest::isStateRequest() const {
 }
 
 bool SecureRequest::needAck() const {
+	Expects(_data != nullptr);
+
 	if (_data->size() <= kMessageBodyPosition) {
 		return false;
 	}
diff --git a/Telegram/SourceFiles/mtproto/core_types.h b/Telegram/SourceFiles/mtproto/core_types.h
index bbf48680c..c5c952da1 100644
--- a/Telegram/SourceFiles/mtproto/core_types.h
+++ b/Telegram/SourceFiles/mtproto/core_types.h
@@ -138,9 +138,9 @@ public:
 
 	static constexpr auto kSaltInts = 2;
 	static constexpr auto kSessionIdInts = 2;
+	static constexpr auto kMessageIdPosition = kSaltInts + kSessionIdInts;
 	static constexpr auto kMessageIdInts = 2;
-	static constexpr auto kSeqNoPosition = kSaltInts
-		+ kSessionIdInts
+	static constexpr auto kSeqNoPosition = kMessageIdPosition
 		+ kMessageIdInts;
 	static constexpr auto kSeqNoInts = 1;
 	static constexpr auto kMessageLengthPosition = kSeqNoPosition
@@ -168,13 +168,19 @@ public:
 	SecureRequestData &operator*() const;
 	explicit operator bool() const;
 
-	void addPadding(bool extended);
-	uint32 messageSize() const;
+	void setMsgId(mtpMsgId msgId);
+	[[nodiscard]] mtpMsgId getMsgId() const;
+
+	void setSeqNo(uint32 seqNo);
+	[[nodiscard]] uint32 getSeqNo() const;
+
+	void addPadding(bool extended, bool old);
+	[[nodiscard]] uint32 messageSize() const;
 
 	// "request-like" wrap for msgIds vector
-	bool isSentContainer() const;
-	bool isStateRequest() const;
-	bool needAck() const;
+	[[nodiscard]] bool isSentContainer() const;
+	[[nodiscard]] bool isStateRequest() const;
+	[[nodiscard]] bool needAck() const;
 
 	using ResponseType = void; // don't know real response type =(
 
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/dcenter.h
index 7fab8d153..d0111fcad 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/dcenter.h
@@ -33,6 +33,11 @@ public:
 	void setConnectionInited(bool connectionInited = true) {
 		QMutexLocker lock(&initLock);
 		_connectionInited = connectionInited;
+		lock.unlock();
+
+		if (connectionInited) {
+			emit connectionWasInited();
+		}
 	}
 
 signals:
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
index 54f713a20..81dded5d4 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
@@ -8,24 +8,143 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/details/mtproto_dc_key_checker.h"
 
 #include "mtproto/mtp_instance.h"
+#include "base/unixtime.h"
+#include "base/openssl_help.h"
+#include "scheme.h"
 
 #include <QtCore/QPointer>
 
 namespace MTP::details {
+namespace {
+
+constexpr auto kBindKeyExpireTimeout = TimeId(3600);
+
+[[nodiscard]] QByteArray EncryptBindAuthKeyInner(
+		const AuthKeyPtr &persistentKey,
+		mtpMsgId realMsgId,
+		const MTPBindAuthKeyInner &data) {
+	auto serialized = SecureRequest::Serialize(data);
+	serialized.setMsgId(realMsgId);
+	serialized.setSeqNo(0);
+	serialized.addPadding(false, true);
+
+	constexpr auto kMsgIdPosition = SecureRequest::kMessageIdPosition;
+	constexpr auto kMinMessageSize = 5;
+
+	const auto sizeInPrimes = serialized->size();
+	const auto messageSize = serialized.messageSize();
+	Assert(messageSize >= kMinMessageSize);
+	Assert(sizeInPrimes >= kMsgIdPosition + messageSize);
+
+	const auto sizeInBytes = sizeInPrimes * sizeof(mtpPrime);
+	const auto padding = sizeInBytes
+		- (kMsgIdPosition + messageSize) * sizeof(mtpPrime);
+
+	// session_id, salt - just random here.
+	bytes::set_random(bytes::make_span(*serialized).subspan(
+		0,
+		kMsgIdPosition * sizeof(mtpPrime)));
+
+	const auto hash = openssl::Sha1(bytes::make_span(*serialized).subspan(
+		0,
+		sizeInBytes - padding));
+	auto msgKey = MTPint128();
+	bytes::copy(
+		bytes::object_as_span(&msgKey),
+		bytes::make_span(hash).subspan(4));
+
+	constexpr auto kAuthKeyIdBytes = 2 * sizeof(mtpPrime);
+	constexpr auto kMessageKeyPosition = kAuthKeyIdBytes;
+	constexpr auto kMessageKeyBytes = 4 * sizeof(mtpPrime);
+	constexpr auto kPrefix = (kAuthKeyIdBytes + kMessageKeyBytes);
+	auto encrypted = QByteArray(kPrefix + sizeInBytes, Qt::Uninitialized);
+	*reinterpret_cast<uint64*>(encrypted.data()) = persistentKey->keyId();
+	*reinterpret_cast<MTPint128*>(encrypted.data() + kMessageKeyPosition)
+		= msgKey;
+
+	aesIgeEncrypt_oldmtp(
+		serialized->constData(),
+		encrypted.data() + kPrefix,
+		sizeInBytes,
+		persistentKey,
+		msgKey);
+
+	return encrypted;
+}
+
+} // namespace
 
 DcKeyChecker::DcKeyChecker(
 	not_null<Instance*> instance,
-	DcId dcId,
-	const AuthKeyPtr &key,
-	FnMut<void()> destroyMe)
+	ShiftedDcId shiftedDcId,
+	const AuthKeyPtr &persistentKey)
 : _instance(instance)
-, _dcId(dcId)
-, _key(key)
-, _destroyMe(std::move(destroyMe)) {
+, _shiftedDcId(shiftedDcId)
+, _persistentKey(persistentKey) {
+}
+
+SecureRequest DcKeyChecker::prepareRequest(
+		const AuthKeyPtr &temporaryKey,
+		uint64 sessionId) {
+	Expects(_requestMsgId == 0);
+
+	const auto nonce = openssl::RandomValue<uint64>();
+	_requestMsgId = base::unixtime::mtproto_msg_id();
+	auto result = SecureRequest::Serialize(MTPauth_BindTempAuthKey(
+		MTP_long(_persistentKey->keyId()),
+		MTP_long(nonce),
+		MTP_int(kBindKeyExpireTimeout),
+		MTP_bytes(EncryptBindAuthKeyInner(
+			_persistentKey,
+			_requestMsgId,
+			MTP_bind_auth_key_inner(
+				MTP_long(nonce),
+				MTP_long(temporaryKey->keyId()),
+				MTP_long(_persistentKey->keyId()),
+				MTP_long(sessionId),
+				MTP_int(kBindKeyExpireTimeout))))));
+	result.setMsgId(_requestMsgId);
+	return result;
+}
+
+bool DcKeyChecker::handleResponse(
+		MTPlong requestMsgId,
+		const mtpBuffer &response) {
+	Expects(!response.isEmpty());
+
+	if (!_requestMsgId || requestMsgId.v != _requestMsgId) {
+		return false;
+	}
+
+	const auto destroyed = [&] {
+		if (response[0] != mtpc_rpc_error) {
+			return false;
+		}
+		auto error = MTPRpcError();
+		auto from = response.begin();
+		const auto end = from + response.size();
+		if (!error.read(from, end)) {
+			return false;
+		}
+		return error.match([&](const MTPDrpc_error &data) {
+			return (data.verror_code().v == 400)
+				&& (data.verror_message().v == "ENCRYPTED_MESSAGE_INVALID");
+		});
+	}();
+
+	const auto instance = _instance;
+	const auto shiftedDcId = _shiftedDcId;
+	const auto keyId = _persistentKey->keyId();
+	_persistentKey->setLastCheckTime(crl::now());
 	crl::on_main(instance, [=] {
-		auto destroy = std::move(_destroyMe);
-		destroy();
+		instance->killSession(shiftedDcId);
+		if (destroyed) {
+			instance->keyDestroyedOnServer(BareDcId(shiftedDcId), keyId);
+		}
 	});
+
+	_requestMsgId = 0;
+	return true;
 }
 
 } // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
index 08f631277..80cb5b4e9 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
@@ -16,19 +16,28 @@ class Instance;
 
 namespace MTP::details {
 
+enum class DcKeyState {
+	MaybeExisting,
+	DefinitelyDestroyed,
+};
+
 class DcKeyChecker final {
 public:
 	DcKeyChecker(
 		not_null<Instance*> instance,
-		DcId dcId,
-		const AuthKeyPtr &key,
-		FnMut<void()> destroyMe);
+		ShiftedDcId shiftedDcId,
+		const AuthKeyPtr &persistentKey);
+
+	[[nodiscard]] SecureRequest prepareRequest(
+		const AuthKeyPtr &temporaryKey,
+		uint64 sessionId);
+	bool handleResponse(MTPlong requestMsgId, const mtpBuffer &response);
 
 private:
-	not_null<Instance*> _instance;
-	DcId _dcId = 0;
-	AuthKeyPtr _key;
-	FnMut<void()> _destroyMe;
+	const not_null<Instance*> _instance;
+	const ShiftedDcId _shiftedDcId = 0;
+	const AuthKeyPtr _persistentKey;
+	mtpMsgId _requestMsgId = 0;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index 60e03840d..9cb1cade2 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -76,12 +76,17 @@ template <typename PQInnerData>
 	constexpr auto kSkipPrimes = 6;
 	constexpr auto kMaxPrimes = 65; // 260 bytes
 
-	const auto p_q_inner_size = tl::count_length(data);
+	using BoxedPQInnerData = std::conditional_t<
+		tl::is_boxed_v<PQInnerData>,
+		PQInnerData,
+		tl::boxed<PQInnerData>>;
+	const auto boxed = BoxedPQInnerData(data);
+	const auto p_q_inner_size = tl::count_length(boxed);
 	const auto sizeInPrimes = (p_q_inner_size >> 2) + kSkipPrimes;
 	if (sizeInPrimes >= kMaxPrimes) {
 		auto tmp = mtpBuffer();
 		tmp.reserve(sizeInPrimes);
-		data.write(tmp);
+		boxed.write(tmp);
 		LOG(("AuthKey Error: too large data for RSA encrypt, size %1").arg(sizeInPrimes * sizeof(mtpPrime)));
 		DEBUG_LOG(("AuthKey Error: bad data for RSA encrypt %1").arg(Logs::mb(&tmp[0], tmp.size() * 4).str()));
 		return {}; // can't be 255-byte string
@@ -90,7 +95,7 @@ template <typename PQInnerData>
 	auto encBuffer = mtpBuffer();
 	encBuffer.reserve(kMaxPrimes);
 	encBuffer.resize(kSkipPrimes);
-	data.write(encBuffer);
+	boxed.write(encBuffer);
 	encBuffer.resize(kMaxPrimes);
 	const auto bytes = bytes::make_span(encBuffer);
 
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 64881911e..728b85fc4 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -7,7 +7,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/mtp_instance.h"
 
-#include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/session.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/dcenter.h"
@@ -34,6 +33,7 @@ namespace {
 
 constexpr auto kConfigBecomesOldIn = 2 * 60 * crl::time(1000);
 constexpr auto kConfigBecomesOldForBlockedIn = 8 * crl::time(1000);
+constexpr auto kCheckKeyEach = 60 * crl::time(1000);
 
 } // namespace
 
@@ -134,6 +134,7 @@ public:
 	void performKeyDestroy(ShiftedDcId shiftedDcId);
 	void completedKeyDestroy(ShiftedDcId shiftedDcId);
 	void checkMainDcKey();
+	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
 
 	void clearKilledSessions();
 	void prepareToDestroy();
@@ -228,8 +229,6 @@ private:
 
 	base::Timer _checkDelayedTimer;
 
-	std::unique_ptr<details::DcKeyChecker> _mainDcKeyChecker;
-
 	// Debug flag to find out how we end up crashing.
 	bool MustNotCreateSessions = false;
 
@@ -1509,10 +1508,11 @@ void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 }
 
 void Instance::Private::checkMainDcKey() {
-	if (_mainDcKeyChecker) {
+	const auto id = mainDcId();
+	const auto shiftedDcId = ShiftDcId(id, kCheckKeyDcShift);
+	if (_sessions.find(shiftedDcId) != _sessions.end()) {
 		return;
 	}
-	const auto id = mainDcId();
 	const auto key = [&] {
 		QReadLocker lock(&_keysForWriteLock);
 		const auto i = _keysForWrite.find(id);
@@ -1521,11 +1521,26 @@ void Instance::Private::checkMainDcKey() {
 	if (!key) {
 		return;
 	}
-	_mainDcKeyChecker = std::make_unique<details::DcKeyChecker>(
-		_instance,
-		id,
-		key,
-		[=] { _mainDcKeyChecker = nullptr; });
+	const auto lastCheckTime = key->lastCheckTime();
+	if (lastCheckTime > 0 && lastCheckTime + kCheckKeyEach >= crl::now()) {
+		return;
+	}
+	_instance->sendDcKeyCheck(shiftedDcId, key);
+}
+
+void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
+	if (dcId == _mainDcId) {
+		for (const auto &[id, dc] : _dcenters) {
+			dc->destroyKey();
+		}
+		restart();
+	} else {
+		const auto i = _dcenters.find(dcId);
+		if (i != end(_dcenters)) {
+			i->second->destroyKey();
+		}
+		restart(dcId);
+	}
 }
 
 void Instance::Private::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
@@ -1782,6 +1797,10 @@ void Instance::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
 	});
 }
 
+void Instance::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
+	_private->keyDestroyedOnServer(dcId, keyId);
+}
+
 void Instance::sendRequest(
 		mtpRequestId requestId,
 		SecureRequest &&request,
@@ -1805,6 +1824,11 @@ void Instance::sendAnything(ShiftedDcId shiftedDcId, crl::time msCanWait) {
 	session->sendAnything(msCanWait);
 }
 
+void Instance::sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key) {
+	const auto session = _private->getSession(shiftedDcId);
+	session->sendDcKeyCheck(key);
+}
+
 Instance::~Instance() {
 	_private->prepareToDestroy();
 }
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 1e8424582..25ce04ac2 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -135,6 +135,7 @@ public:
 	}
 
 	void sendAnything(ShiftedDcId shiftedDcId = 0, crl::time msCanWait = 0);
+	void sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key);
 
 	void restart();
 	void restart(ShiftedDcId shiftedDcId);
@@ -174,6 +175,7 @@ public:
 	bool isKeysDestroyer() const;
 	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
 	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
+	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
 
 	void requestConfig();
 	void requestConfigIfOld();
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index d6c182c09..385c2e634 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/session.h"
 
+#include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/connection.h"
 #include "mtproto/dcenter.h"
 #include "mtproto/auth_key.h"
@@ -77,6 +78,10 @@ void SessionData::setKey(const AuthKeyPtr &key) {
 	}
 }
 
+void SessionData::setKeyForCheck(const AuthKeyPtr &key) {
+	_dcKeyForCheck = key;
+}
+
 void SessionData::notifyConnectionInited(const ConnectionOptions &options) {
 	QWriteLocker locker(&_lock);
 	if (options.cloudLangCode == _options.cloudLangCode
@@ -157,7 +162,7 @@ void Session::start() {
 }
 
 void Session::createDcData() {
-	if (_dc) {
+	if (_dc || GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift) {
 		return;
 	}
 	_dc = _instance->getDcById(_shiftedDcId);
@@ -212,7 +217,9 @@ void Session::refreshOptions() {
 }
 
 void Session::reInitConnection() {
-	_dc->setConnectionInited(false);
+	if (_dc) {
+		_dc->setConnectionInited(false);
+	}
 	_data.setConnectionInited(false);
 	restart();
 }
@@ -242,6 +249,11 @@ void Session::unpaused() {
 	}
 }
 
+void Session::sendDcKeyCheck(const AuthKeyPtr &key) {
+	_data.setKeyForCheck(key);
+	needToResumeAndSend();
+}
+
 void Session::sendAnything(qint64 msCanWait) {
 	if (_killed) {
 		DEBUG_LOG(("Session Error: can't send anything in a killed session"));
@@ -550,10 +562,12 @@ void Session::sendPrepared(
 }
 
 QReadWriteLock *Session::keyMutex() const {
-	return _dc->keyMutex();
+	return _dc ? _dc->keyMutex() : nullptr;
 }
 
 void Session::authKeyCreatedForDC() {
+	Expects(_dc != nullptr);
+
 	DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, emitting authKeyCreated(), dcWithShift %1").arg(_shiftedDcId));
 	_data.setKey(_dc->getKey());
 	emit authKeyCreated();
@@ -561,31 +575,37 @@ void Session::authKeyCreatedForDC() {
 
 void Session::notifyKeyCreated(AuthKeyPtr &&key) {
 	DEBUG_LOG(("AuthKey Info: Session::keyCreated(), setting, dcWithShift %1").arg(_shiftedDcId));
-	_dc->setKey(std::move(key));
+	if (_dc) {
+		_dc->setKey(std::move(key));
+	} else {
+		_data.setKey(std::move(key));
+		emit authKeyCreated();
+	}
 }
 
 void Session::connectionWasInitedForDC() {
+	Expects(_dc != nullptr);
+
 	DEBUG_LOG(("MTP Info: Session::connectionWasInitedForDC slot, dcWithShift %1").arg(_shiftedDcId));
 	_data.setConnectionInited();
 }
 
 void Session::notifyDcConnectionInited() {
 	DEBUG_LOG(("MTP Info: emitting MTProtoDC::connectionWasInited(), dcWithShift %1").arg(_shiftedDcId));
-	_dc->setConnectionInited();
-	emit _dc->connectionWasInited();
+	if (_dc) {
+		_dc->setConnectionInited();
+	} else {
+		_data.setConnectionInited();
+	}
 }
 
 void Session::destroyKey() {
-	if (!_dc) {
-		return;
-	}
-
-	if (_data.getKey()) {
+	if (const auto key = _data.getKey()) {
 		DEBUG_LOG(("MTP Info: destroying auth_key for dcWithShift %1").arg(_shiftedDcId));
-		if (_data.getKey() == _dc->getKey()) {
+		if (_dc && _dc->getKey() == key) {
 			_dc->destroyKey();
 		}
-		_data.setKey(AuthKeyPtr());
+		_data.setKey(nullptr);
 	}
 }
 
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index f53a356fe..b91efbd5e 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -184,6 +184,11 @@ public:
 	}
 	void setKey(const AuthKeyPtr &key);
 
+	const AuthKeyPtr &getKeyForCheck() const {
+		return _dcKeyForCheck;
+	}
+	void setKeyForCheck(const AuthKeyPtr &key);
+
 	bool isCheckedKey() const {
 		QReadLocker locker(&_lock);
 		return _keyChecked;
@@ -193,7 +198,7 @@ public:
 		_keyChecked = checked;
 	}
 
-	not_null<QReadWriteLock*> keyMutex() const;
+	QReadWriteLock *keyMutex() const;
 
 	not_null<QReadWriteLock*> toSendMutex() const {
 		return &_toSendLock;
@@ -291,6 +296,7 @@ private:
 	not_null<Session*> _owner;
 
 	AuthKeyPtr _authKey;
+	AuthKeyPtr _dcKeyForCheck;
 	bool _keyChecked = false;
 	bool _layerInited = false;
 	ConnectionOptions _options;
@@ -345,6 +351,8 @@ public:
 	int32 getState() const;
 	QString transport() const;
 
+	void sendDcKeyCheck(const AuthKeyPtr &key);
+
 	// Nulls msgId and seqNo in request, if newRequest = true.
 	void sendPrepared(
 		const SecureRequest &request,
@@ -393,6 +401,7 @@ private:
 
 	ShiftedDcId _shiftedDcId = 0;
 	std::shared_ptr<Dcenter> _dc;
+	AuthKeyPtr _dcKeyForCheck;
 
 	crl::time _msSendCall = 0;
 	crl::time _msWait = 0;
@@ -404,9 +413,38 @@ private:
 
 };
 
-inline not_null<QReadWriteLock*> SessionData::keyMutex() const {
+inline QReadWriteLock *SessionData::keyMutex() const {
 	return _owner->keyMutex();
 }
 
+class ReadLockerAttempt {
+public:
+	ReadLockerAttempt(QReadWriteLock *lock) : _lock(lock), _locked(_lock ? _lock->tryLockForRead() : true) {
+	}
+	ReadLockerAttempt(const ReadLockerAttempt &other) = delete;
+	ReadLockerAttempt &operator=(const ReadLockerAttempt &other) = delete;
+	ReadLockerAttempt(ReadLockerAttempt &&other) : _lock(other._lock), _locked(base::take(other._locked)) {
+	}
+	ReadLockerAttempt &operator=(ReadLockerAttempt &&other) {
+		_lock = other._lock;
+		_locked = base::take(other._locked);
+		return *this;
+	}
+	~ReadLockerAttempt() {
+		if (_lock && _locked) {
+			_lock->unlock();
+		}
+	}
+
+	operator bool() const {
+		return _locked;
+	}
+
+private:
+	QReadWriteLock *_lock = nullptr;
+	bool _locked = false;
+
+};
+
 } // namespace internal
 } // namespace MTP

From 8b14249cd2be01e32ef3cf096ce9e60bd1cd4095 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 14 Nov 2019 18:29:45 +0300
Subject: [PATCH 11/91] Move DumpToText from Telegram to lib_mtproto.

---
 .../codegen/scheme/codegen_scheme.py          |   5 +-
 Telegram/SourceFiles/mtproto/connection.cpp   |   5 +-
 Telegram/SourceFiles/mtproto/core_types.cpp   | 148 ---------------
 Telegram/SourceFiles/mtproto/core_types.h     |  74 --------
 .../mtproto/details/mtproto_dump_to_text.cpp  | 168 ++++++++++++++++++
 .../mtproto/details/mtproto_dump_to_text.h    |  81 +++++++++
 Telegram/gyp/Telegram.gyp                     |   1 -
 Telegram/gyp/lib_mtproto.gyp                  |   2 +
 Telegram/gyp/lib_scheme.gyp                   |   2 +
 Telegram/lib_base                             |   2 +-
 Telegram/lib_tl                               |   2 +-
 11 files changed, 262 insertions(+), 228 deletions(-)
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h

diff --git a/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py b/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
index 08e546979..1193e6afd 100644
--- a/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
+++ b/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
@@ -28,7 +28,6 @@ generate({
     'buffer': 'mtpBuffer',
   },
   'sections': [
-    'serialization',
     'read-write',
   ],
 
@@ -91,4 +90,8 @@ generate({
   },
   'builtinInclude': 'mtproto/core_types.h',
 
+  'dumpToText': {
+    'include': 'mtproto/details/mtproto_dump_to_text.h',
+  },
+
 })
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 38b902067..2cb5735da 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "mtproto/details/mtproto_dc_key_creator.h"
 #include "mtproto/details/mtproto_dc_key_checker.h"
+#include "mtproto/details/mtproto_dump_to_text.h"
 #include "mtproto/session.h"
 #include "mtproto/rsa_public_key.h"
 #include "mtproto/rpc_sender.h"
@@ -1433,7 +1434,7 @@ void ConnectionPrivate::handleReceived() {
 		auto from = decryptedInts + kEncryptedHeaderIntsCount;
 		auto end = from + (messageLength / kIntSize);
 		auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
-		MTP_LOG(_shiftedDcId, ("Recv: ") + mtpTextSerialize(sfrom, end));
+		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end));
 
 		bool needToHandle = false;
 		{
@@ -2622,7 +2623,7 @@ bool ConnectionPrivate::sendSecureRequest(
 	memcpy(request->data() + 2, &session, 2 * sizeof(mtpPrime));
 
 	auto from = request->constData() + 4;
-	MTP_LOG(_shiftedDcId, ("Send: ") + mtpTextSerialize(from, from + messageSize));
+	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize));
 
 #ifdef TDESKTOP_MTPROTO_OLD
 	uint32 padding = fullSize - 4 - messageSize;
diff --git a/Telegram/SourceFiles/mtproto/core_types.cpp b/Telegram/SourceFiles/mtproto/core_types.cpp
index 12b250919..50e62f95e 100644
--- a/Telegram/SourceFiles/mtproto/core_types.cpp
+++ b/Telegram/SourceFiles/mtproto/core_types.cpp
@@ -7,8 +7,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/core_types.h"
 
-#include "zlib.h"
-
 namespace MTP {
 namespace {
 
@@ -175,149 +173,3 @@ const void *SecureRequest::dataInBytes() const {
 }
 
 } // namespace MTP
-
-bool mtpTextSerializeCore(MTPStringLogger &to, const mtpPrime *&from, const mtpPrime *end, mtpTypeId cons, uint32 level, mtpPrime vcons) {
-	switch (mtpTypeId(cons)) {
-	case mtpc_int: {
-		MTPint value;
-		if (value.read(from, end, cons)) {
-			to.add(QString::number(value.v)).add(" [INT]");
-			return true;
-		}
-	} break;
-
-	case mtpc_long: {
-		MTPlong value;
-		if (value.read(from, end, cons)) {
-			to.add(QString::number(value.v)).add(" [LONG]");
-			return true;
-		}
-	} break;
-
-	case mtpc_int128: {
-		MTPint128 value;
-		if (value.read(from, end, cons)) {
-			to.add(QString::number(value.h)).add(" * 2^64 + ").add(QString::number(value.l)).add(" [INT128]");
-			return true;
-		}
-	} break;
-
-	case mtpc_int256: {
-		MTPint256 value;
-		if (value.read(from, end, cons)) {
-			to.add(QString::number(value.h.h)).add(" * 2^192 + ").add(QString::number(value.h.l)).add(" * 2^128 + ").add(QString::number(value.l.h)).add(" * 2 ^ 64 + ").add(QString::number(value.l.l)).add(" [INT256]");
-			return true;
-		}
-	} break;
-
-	case mtpc_double: {
-		MTPdouble value;
-		if (value.read(from, end, cons)) {
-			to.add(QString::number(value.v)).add(" [DOUBLE]");
-			return true;
-		}
-	} break;
-
-	case mtpc_string: {
-		MTPstring value;
-		if (value.read(from, end, cons)) {
-			auto strUtf8 = value.v;
-			auto str = QString::fromUtf8(strUtf8);
-			if (str.toUtf8() == strUtf8) {
-				to.add("\"").add(str.replace('\\', "\\\\").replace('"', "\\\"").replace('\n', "\\n")).add("\" [STRING]");
-			} else if (strUtf8.size() < 64) {
-				to.add(Logs::mb(strUtf8.constData(), strUtf8.size()).str()).add(" [").add(QString::number(strUtf8.size())).add(" BYTES]");
-			} else {
-				to.add(Logs::mb(strUtf8.constData(), 16).str()).add("... [").add(QString::number(strUtf8.size())).add(" BYTES]");
-			}
-			return true;
-		}
-	} break;
-
-	case mtpc_vector: {
-		if (from < end) {
-			int32 cnt = *(from++);
-			to.add("[ vector<0x").add(QString::number(vcons, 16)).add(">");
-			if (cnt) {
-				to.add("\n").addSpaces(level);
-				for (int32 i = 0; i < cnt; ++i) {
-					to.add("  ");
-					if (!mtpTextSerializeType(to, from, end, vcons, level + 1)) {
-						return false;
-					}
-					to.add(",\n").addSpaces(level);
-				}
-			} else {
-				to.add(" ");
-			}
-			to.add("]");
-			return true;
-		}
-	} break;
-
-	case mtpc_gzip_packed: {
-		MTPstring packed;
-		// read packed string as serialized mtp string type
-		if (!packed.read(from, end)) {
-			return false;
-		}
-		uint32 packedLen = packed.v.size(), unpackedChunk = packedLen;
-		mtpBuffer result; // * 4 because of mtpPrime type
-		result.resize(0);
-
-		z_stream stream;
-		stream.zalloc = nullptr;
-		stream.zfree = nullptr;
-		stream.opaque = nullptr;
-		stream.avail_in = 0;
-		stream.next_in = nullptr;
-		int res = inflateInit2(&stream, 16 + MAX_WBITS);
-		if (res != Z_OK) {
-			return false;
-		}
-		stream.avail_in = packedLen;
-		stream.next_in = reinterpret_cast<Bytef*>(packed.v.data());
-		stream.avail_out = 0;
-		while (!stream.avail_out) {
-			result.resize(result.size() + unpackedChunk);
-			stream.avail_out = unpackedChunk * sizeof(mtpPrime);
-			stream.next_out = (Bytef*)&result[result.size() - unpackedChunk];
-			int res = inflate(&stream, Z_NO_FLUSH);
-			if (res != Z_OK && res != Z_STREAM_END) {
-				inflateEnd(&stream);
-				return false;
-			}
-		}
-		if (stream.avail_out & 0x03) {
-			return false;
-		}
-		result.resize(result.size() - (stream.avail_out >> 2));
-		inflateEnd(&stream);
-
-		if (result.empty()) {
-			return false;
-		}
-		const mtpPrime *newFrom = result.constData(), *newEnd = result.constData() + result.size();
-		to.add("[GZIPPED] ");
-		return mtpTextSerializeType(to, newFrom, newEnd, 0, level);
-	} break;
-
-	default: {
-		for (uint32 i = 1; i < mtpLayerMaxSingle; ++i) {
-			if (cons == mtpLayers[i]) {
-				to.add("[LAYER").add(QString::number(i + 1)).add("] ");
-				return mtpTextSerializeType(to, from, end, 0, level);
-			}
-		}
-		if (cons == mtpc_invokeWithLayer) {
-			if (from >= end) {
-				return false;
-			}
-			int32 layer = *(from++);
-			to.add("[LAYER").add(QString::number(layer)).add("] ");
-			return mtpTextSerializeType(to, from, end, 0, level);
-		}
-	} break;
-	}
-	return false;
-}
diff --git a/Telegram/SourceFiles/mtproto/core_types.h b/Telegram/SourceFiles/mtproto/core_types.h
index c5c952da1..58db5caa4 100644
--- a/Telegram/SourceFiles/mtproto/core_types.h
+++ b/Telegram/SourceFiles/mtproto/core_types.h
@@ -335,80 +335,6 @@ inline MTPvector<T> MTP_vector() {
 	return tl::make_vector<T>();
 }
 
-// Human-readable text serialization
-
-struct MTPStringLogger {
-	static constexpr auto kBufferSize = 1024 * 1024; // 1 mb start size
-
-	MTPStringLogger()
-	: p(new char[kBufferSize])
-	, alloced(kBufferSize) {
-	}
-	~MTPStringLogger() {
-		delete[] p;
-	}
-
-	MTPStringLogger &add(const QString &data) {
-		auto d = data.toUtf8();
-		return add(d.constData(), d.size());
-	}
-
-	MTPStringLogger &add(const char *data, int32 len = -1) {
-		if (len < 0) len = strlen(data);
-		if (!len) return (*this);
-
-		ensureLength(len);
-		memcpy(p + size, data, len);
-		size += len;
-		return (*this);
-	}
-
-	MTPStringLogger &addSpaces(int32 level) {
-		int32 len = level * 2;
-		if (!len) return (*this);
-
-		ensureLength(len);
-		for (char *ptr = p + size, *end = ptr + len; ptr != end; ++ptr) {
-			*ptr = ' ';
-		}
-		size += len;
-		return (*this);
-	}
-
-	MTPStringLogger &error(const char *problem = "could not decode type") {
-		return add("[ERROR] (").add(problem).add(")");
-	}
-
-	void ensureLength(int32 add) {
-		if (size + add <= alloced) return;
-
-		int32 newsize = size + add;
-		if (newsize % kBufferSize) {
-			newsize += kBufferSize - (newsize % kBufferSize);
-		}
-		char *b = new char[newsize];
-		memcpy(b, p, size);
-		alloced = newsize;
-		delete[] p;
-		p = b;
-	}
-
-	char *p = nullptr;
-	int size = 0;
-	int alloced = 0;
-
-};
-
-[[nodiscard]] bool mtpTextSerializeType(MTPStringLogger &to, const mtpPrime *&from, const mtpPrime *end, mtpPrime cons = 0, uint32 level = 0, mtpPrime vcons = 0);
-
-[[nodiscard]] bool mtpTextSerializeCore(MTPStringLogger &to, const mtpPrime *&from, const mtpPrime *end, mtpTypeId cons, uint32 level, mtpPrime vcons = 0);
-
-inline QString mtpTextSerialize(const mtpPrime *&from, const mtpPrime *end) {
-	MTPStringLogger to;
-	[[maybe_unused]] bool result = mtpTextSerializeType(to, from, end, mtpc_core_message);
-	return QString::fromUtf8(to.p, to.size);
-}
-
 namespace tl {
 
 template <typename Accumulator>
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.cpp
new file mode 100644
index 000000000..2ec424f6c
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.cpp
@@ -0,0 +1,168 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/details/mtproto_dump_to_text.h"
+
+#include "base/zlib_help.h"
+#include "scheme-dump_to_text.h"
+#include "scheme.h"
+
+namespace MTP::details {
+
+bool DumpToTextCore(DumpToTextBuffer &to, const mtpPrime *&from, const mtpPrime *end, mtpTypeId cons, uint32 level, mtpPrime vcons) {
+	switch (mtpTypeId(cons)) {
+	case mtpc_int: {
+		MTPint value;
+		if (value.read(from, end, cons)) {
+			to.add(QString::number(value.v)).add(" [INT]");
+			return true;
+		}
+	} break;
+
+	case mtpc_long: {
+		MTPlong value;
+		if (value.read(from, end, cons)) {
+			to.add(QString::number(value.v)).add(" [LONG]");
+			return true;
+		}
+	} break;
+
+	case mtpc_int128: {
+		MTPint128 value;
+		if (value.read(from, end, cons)) {
+			to.add(QString::number(value.h)).add(" * 2^64 + ").add(QString::number(value.l)).add(" [INT128]");
+			return true;
+		}
+	} break;
+
+	case mtpc_int256: {
+		MTPint256 value;
+		if (value.read(from, end, cons)) {
+			to.add(QString::number(value.h.h)).add(" * 2^192 + ").add(QString::number(value.h.l)).add(" * 2^128 + ").add(QString::number(value.l.h)).add(" * 2 ^ 64 + ").add(QString::number(value.l.l)).add(" [INT256]");
+			return true;
+		}
+	} break;
+
+	case mtpc_double: {
+		MTPdouble value;
+		if (value.read(from, end, cons)) {
+			to.add(QString::number(value.v)).add(" [DOUBLE]");
+			return true;
+		}
+	} break;
+
+	case mtpc_string: {
+		MTPstring value;
+		if (value.read(from, end, cons)) {
+			auto strUtf8 = value.v;
+			auto str = QString::fromUtf8(strUtf8);
+			if (str.toUtf8() == strUtf8) {
+				to.add("\"").add(str.replace('\\', "\\\\").replace('"', "\\\"").replace('\n', "\\n")).add("\" [STRING]");
+			} else if (strUtf8.size() < 64) {
+				to.add(Logs::mb(strUtf8.constData(), strUtf8.size()).str()).add(" [").add(QString::number(strUtf8.size())).add(" BYTES]");
+			} else {
+				to.add(Logs::mb(strUtf8.constData(), 16).str()).add("... [").add(QString::number(strUtf8.size())).add(" BYTES]");
+			}
+			return true;
+		}
+	} break;
+
+	case mtpc_vector: {
+		if (from < end) {
+			int32 cnt = *(from++);
+			to.add("[ vector<0x").add(QString::number(vcons, 16)).add(">");
+			if (cnt) {
+				to.add("\n").addSpaces(level);
+				for (int32 i = 0; i < cnt; ++i) {
+					to.add("  ");
+					if (!DumpToTextType(to, from, end, vcons, level + 1)) {
+						return false;
+					}
+					to.add(",\n").addSpaces(level);
+				}
+			} else {
+				to.add(" ");
+			}
+			to.add("]");
+			return true;
+		}
+	} break;
+
+	case mtpc_gzip_packed: {
+		MTPstring packed;
+		// read packed string as serialized mtp string type
+		if (!packed.read(from, end)) {
+			return false;
+		}
+		uint32 packedLen = packed.v.size(), unpackedChunk = packedLen;
+		mtpBuffer result; // * 4 because of mtpPrime type
+		result.resize(0);
+
+		z_stream stream;
+		stream.zalloc = nullptr;
+		stream.zfree = nullptr;
+		stream.opaque = nullptr;
+		stream.avail_in = 0;
+		stream.next_in = nullptr;
+		int res = inflateInit2(&stream, 16 + MAX_WBITS);
+		if (res != Z_OK) {
+			return false;
+		}
+		stream.avail_in = packedLen;
+		stream.next_in = reinterpret_cast<Bytef*>(packed.v.data());
+		stream.avail_out = 0;
+		while (!stream.avail_out) {
+			result.resize(result.size() + unpackedChunk);
+			stream.avail_out = unpackedChunk * sizeof(mtpPrime);
+			stream.next_out = (Bytef*)&result[result.size() - unpackedChunk];
+			int res = inflate(&stream, Z_NO_FLUSH);
+			if (res != Z_OK && res != Z_STREAM_END) {
+				inflateEnd(&stream);
+				return false;
+			}
+		}
+		if (stream.avail_out & 0x03) {
+			return false;
+		}
+		result.resize(result.size() - (stream.avail_out >> 2));
+		inflateEnd(&stream);
+
+		if (result.empty()) {
+			return false;
+		}
+		const mtpPrime *newFrom = result.constData(), *newEnd = result.constData() + result.size();
+		to.add("[GZIPPED] ");
+		return DumpToTextType(to, newFrom, newEnd, 0, level);
+	} break;
+
+	default: {
+		for (uint32 i = 1; i < mtpLayerMaxSingle; ++i) {
+			if (cons == mtpLayers[i]) {
+				to.add("[LAYER").add(QString::number(i + 1)).add("] ");
+				return DumpToTextType(to, from, end, 0, level);
+			}
+		}
+		if (cons == mtpc_invokeWithLayer) {
+			if (from >= end) {
+				return false;
+			}
+			int32 layer = *(from++);
+			to.add("[LAYER").add(QString::number(layer)).add("] ");
+			return DumpToTextType(to, from, end, 0, level);
+		}
+	} break;
+	}
+	return false;
+}
+
+QString DumpToText(const mtpPrime *&from, const mtpPrime *end) {
+	DumpToTextBuffer to;
+	[[maybe_unused]] bool result = DumpToTextType(to, from, end, mtpc_core_message);
+	return QString::fromUtf8(to.p, to.size);
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h b/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h
new file mode 100644
index 000000000..f24361655
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h
@@ -0,0 +1,81 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "mtproto/core_types.h"
+
+namespace MTP::details {
+
+// Human-readable text serialization
+QString DumpToText(const mtpPrime *&from, const mtpPrime *end);
+
+struct DumpToTextBuffer {
+	static constexpr auto kBufferSize = 1024 * 1024; // 1 mb start size
+
+	DumpToTextBuffer()
+		: p(new char[kBufferSize])
+		, alloced(kBufferSize) {
+	}
+	~DumpToTextBuffer() {
+		delete[] p;
+	}
+
+	DumpToTextBuffer &add(const QString &data) {
+		auto d = data.toUtf8();
+		return add(d.constData(), d.size());
+	}
+
+	DumpToTextBuffer &add(const char *data, int32 len = -1) {
+		if (len < 0) len = strlen(data);
+		if (!len) return (*this);
+
+		ensureLength(len);
+		memcpy(p + size, data, len);
+		size += len;
+		return (*this);
+	}
+
+	DumpToTextBuffer &addSpaces(int32 level) {
+		int32 len = level * 2;
+		if (!len) return (*this);
+
+		ensureLength(len);
+		for (char *ptr = p + size, *end = ptr + len; ptr != end; ++ptr) {
+			*ptr = ' ';
+		}
+		size += len;
+		return (*this);
+	}
+
+	DumpToTextBuffer &error(const char *problem = "could not decode type") {
+		return add("[ERROR] (").add(problem).add(")");
+	}
+
+	void ensureLength(int32 add) {
+		if (size + add <= alloced) return;
+
+		int32 newsize = size + add;
+		if (newsize % kBufferSize) {
+			newsize += kBufferSize - (newsize % kBufferSize);
+		}
+		char *b = new char[newsize];
+		memcpy(b, p, size);
+		alloced = newsize;
+		delete[] p;
+		p = b;
+	}
+
+	char *p = nullptr;
+	int size = 0;
+	int alloced = 0;
+
+};
+
+[[nodiscard]] bool DumpToTextCore(DumpToTextBuffer &to, const mtpPrime *&from, const mtpPrime *end, mtpTypeId cons, uint32 level, mtpPrime vcons = 0);
+
+} // namespace MTP::details
diff --git a/Telegram/gyp/Telegram.gyp b/Telegram/gyp/Telegram.gyp
index b141322a9..7f080fba8 100644
--- a/Telegram/gyp/Telegram.gyp
+++ b/Telegram/gyp/Telegram.gyp
@@ -99,7 +99,6 @@
       '<(SHARED_INTERMEDIATE_DIR)',
       '<(libs_loc)/breakpad/src',
       '<(libs_loc)/lzma/C',
-      '<(libs_loc)/zlib',
       '<(libs_loc)/openal-soft/include',
       '<(libs_loc)/opus/include',
       '<(minizip_loc)',
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index f86c004ff..bbc7a3e17 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -38,6 +38,8 @@
       '<(src_loc)/mtproto/details/mtproto_dc_key_checker.h',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.cpp',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.h',
+      '<(src_loc)/mtproto/details/mtproto_dump_to_text.cpp',
+      '<(src_loc)/mtproto/details/mtproto_dump_to_text.h',
       '<(src_loc)/mtproto/mtproto_dh_utils.cpp',
       '<(src_loc)/mtproto/mtproto_dh_utils.h',
       '<(src_loc)/mtproto/mtproto_proxy_data.cpp',
diff --git a/Telegram/gyp/lib_scheme.gyp b/Telegram/gyp/lib_scheme.gyp
index 265c27a3f..2975bc30f 100644
--- a/Telegram/gyp/lib_scheme.gyp
+++ b/Telegram/gyp/lib_scheme.gyp
@@ -50,6 +50,8 @@
       'outputs': [
         '<(SHARED_INTERMEDIATE_DIR)/scheme.cpp',
         '<(SHARED_INTERMEDIATE_DIR)/scheme.h',
+        '<(SHARED_INTERMEDIATE_DIR)/scheme-dump_to_text.cpp',
+        '<(SHARED_INTERMEDIATE_DIR)/scheme-dump_to_text.h',
       ],
       'action': [
         'python', '<(src_loc)/codegen/scheme/codegen_scheme.py',
diff --git a/Telegram/lib_base b/Telegram/lib_base
index c1941996f..bdc4127ff 160000
--- a/Telegram/lib_base
+++ b/Telegram/lib_base
@@ -1 +1 @@
-Subproject commit c1941996febf02c4216a16fc6037e7473bcf9d00
+Subproject commit bdc4127ff5d5a14eb9d04986725ef7ec94e6d807
diff --git a/Telegram/lib_tl b/Telegram/lib_tl
index 89a1e3fed..2bf101114 160000
--- a/Telegram/lib_tl
+++ b/Telegram/lib_tl
@@ -1 +1 @@
-Subproject commit 89a1e3fed24bc0bfc268fa0352e7d2658ee4ef22
+Subproject commit 2bf101114f0a54c868a2703a9a80c06c0f2d2c41

From 3a7faffa3a8975c854a5f55399c31ca4f51f61a9 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 14 Nov 2019 20:03:44 +0300
Subject: [PATCH 12/91] Use thread_local counter in logs for thread index.

---
 Telegram/SourceFiles/logs.cpp               | 14 +++++++++-----
 Telegram/SourceFiles/mtproto/connection.cpp |  2 +-
 Telegram/SourceFiles/mtproto/connection.h   | 18 ------------------
 3 files changed, 10 insertions(+), 24 deletions(-)

diff --git a/Telegram/SourceFiles/logs.cpp b/Telegram/SourceFiles/logs.cpp
index 5a3955955..348a26213 100644
--- a/Telegram/SourceFiles/logs.cpp
+++ b/Telegram/SourceFiles/logs.cpp
@@ -8,10 +8,15 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "logs.h"
 
 #include "platform/platform_specific.h"
-#include "mtproto/connection.h"
 #include "core/crash_reports.h"
 #include "core/launcher.h"
 
+namespace {
+
+std::atomic<int> ThreadCounter/* = 0*/;
+
+} // namespace
+
 enum LogDataType {
 	LogDataMain,
 	LogDataDebug,
@@ -45,11 +50,10 @@ QString _logsFilePath(LogDataType type, const QString &postfix = QString()) {
 
 int32 LogsStartIndexChosen = -1;
 QString _logsEntryStart() {
-	static int32 index = 0;
-	QDateTime tm(QDateTime::currentDateTime());
+	static thread_local auto threadId = ThreadCounter++;
+	static auto index = 0;
 
-	auto thread = qobject_cast<MTP::internal::Thread*>(QThread::currentThread());
-	auto threadId = thread ? thread->getThreadIndex() : 0;
+	const auto tm = QDateTime::currentDateTime();
 
 	return QString("[%1 %2-%3]").arg(tm.toString("hh:mm:ss.zzz")).arg(QString("%1").arg(threadId, 2, 10, QChar('0'))).arg(++index, 7, 10, QChar('0'));
 }
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 2cb5735da..d7e0a95bf 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -103,7 +103,7 @@ Connection::Connection(not_null<Instance*> instance)
 void Connection::start(SessionData *sessionData, ShiftedDcId shiftedDcId) {
 	Expects(_thread == nullptr && _private == nullptr);
 
-	_thread = std::make_unique<Thread>();
+	_thread = std::make_unique<QThread>();
 	auto newData = std::make_unique<ConnectionPrivate>(
 		_instance,
 		_thread.get(),
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 337525e6b..912ac8fec 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -33,24 +33,6 @@ class SessionData;
 class RSAPublicKey;
 struct ConnectionOptions;
 
-class Thread : public QThread {
-	// The Q_OBJECT meta info is used for qobject_cast!
-	Q_OBJECT
-
-public:
-	Thread() {
-		static int ThreadCounter = 0;
-		_threadIndex = ++ThreadCounter;
-	}
-	int getThreadIndex() const {
-		return _threadIndex;
-	}
-
-private:
-	int _threadIndex = 0;
-
-};
-
 class Connection {
 public:
 	enum ConnectionType {

From 1e252a65056d9db06ead0fdec67e6bef1f850d1f Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 14 Nov 2019 20:05:10 +0300
Subject: [PATCH 13/91] Remove old debug information.

---
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 728b85fc4..c0eed709c 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -229,9 +229,6 @@ private:
 
 	base::Timer _checkDelayedTimer;
 
-	// Debug flag to find out how we end up crashing.
-	bool MustNotCreateSessions = false;
-
 };
 
 Instance::Private::Private(
@@ -273,14 +270,12 @@ void Instance::Private::start(Config &&config) {
 
 	if (isKeysDestroyer()) {
 		for (auto &dc : _dcenters) {
-			Assert(!MustNotCreateSessions);
 			auto shiftedDcId = dc.first;
 			auto session = std::make_unique<internal::Session>(_instance, shiftedDcId);
 			auto it = _sessions.emplace(shiftedDcId, std::move(session)).first;
 			it->second->start();
 		}
 	} else if (_mainDcId != Config::kNoneMainDc) {
-		Assert(!MustNotCreateSessions);
 		auto main = std::make_unique<internal::Session>(_instance, _mainDcId);
 		_mainSession = main.get();
 		_sessions.emplace(_mainDcId, std::move(main));
@@ -581,7 +576,6 @@ void Instance::Private::killSession(ShiftedDcId shiftedDcId) {
 	if (checkIfMainAndKill(shiftedDcId)) {
 		checkIfMainAndKill(_mainDcId);
 
-		Assert(!MustNotCreateSessions);
 		auto main = std::make_unique<internal::Session>(_instance, _mainDcId);
 		_mainSession = main.get();
 		_sessions.emplace(_mainDcId, std::move(main));
@@ -715,7 +709,6 @@ void Instance::Private::addKeysForDestroy(AuthKeysList &&keys) {
 		auto dc = std::make_shared<internal::Dcenter>(_instance, dcId, std::move(key));
 		_dcenters.emplace(shiftedDcId, std::move(dc));
 
-		Assert(!MustNotCreateSessions);
 		auto session = std::make_unique<internal::Session>(_instance, shiftedDcId);
 		auto it = _sessions.emplace(shiftedDcId, std::move(session)).first;
 		it->second->start();
@@ -1450,7 +1443,6 @@ not_null<internal::Session*> Instance::Private::getSession(
 
 	auto it = _sessions.find(shiftedDcId);
 	if (it == _sessions.cend()) {
-		Assert(!MustNotCreateSessions);
 		it = _sessions.emplace(shiftedDcId, std::make_unique<internal::Session>(_instance, shiftedDcId)).first;
 		it->second->start();
 	}
@@ -1576,8 +1568,6 @@ void Instance::Private::prepareToDestroy() {
 		session.second->kill();
 	}
 	_mainSession = nullptr;
-
-	MustNotCreateSessions = true;
 }
 
 Instance::Instance(not_null<DcOptions*> options, Mode mode, Config &&config)

From fe1e627cacf742e384036c3f6e4f9bfc7eaa6096 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 14 Nov 2019 20:39:15 +0300
Subject: [PATCH 14/91] Improve working with sessions.

---
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 235 ++++++++++--------
 Telegram/SourceFiles/mtproto/session.cpp      |  11 +-
 Telegram/SourceFiles/mtproto/session.h        |   9 +-
 3 files changed, 139 insertions(+), 116 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index c0eed709c..cc3c37ed2 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -35,6 +35,8 @@ constexpr auto kConfigBecomesOldIn = 2 * 60 * crl::time(1000);
 constexpr auto kConfigBecomesOldForBlockedIn = 8 * crl::time(1000);
 constexpr auto kCheckKeyEach = 60 * crl::time(1000);
 
+using namespace internal;
+
 } // namespace
 
 class Instance::Private : private Sender {
@@ -79,12 +81,17 @@ public:
 	void reInitConnection(DcId dcId);
 	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
 
-	std::shared_ptr<internal::Dcenter> getDcById(ShiftedDcId shiftedDcId);
+	std::shared_ptr<Dcenter> getDcById(ShiftedDcId shiftedDcId);
+	std::shared_ptr<Dcenter> findDc(ShiftedDcId shiftedDcId);
+	std::shared_ptr<Dcenter> addDc(
+		ShiftedDcId shiftedDcId,
+		AuthKeyPtr &&key = nullptr);
+	void removeDc(ShiftedDcId shiftedDcId);
 	void unpaused();
 
 	void queueQuittingConnection(
-		std::unique_ptr<internal::Connection> &&connection);
-	void connectionFinished(internal::Connection *connection);
+		std::unique_ptr<Connection> &&connection);
+	void connectionFinished(Connection *connection);
 
 	void sendRequest(
 		mtpRequestId requestId,
@@ -121,7 +128,7 @@ public:
 	void setSessionResetHandler(Fn<void(ShiftedDcId shiftedDcId)> handler);
 	void clearGlobalHandlers();
 
-	not_null<internal::Session*> getSession(ShiftedDcId shiftedDcId);
+	[[nodiscard]] not_null<Session*> getSession(ShiftedDcId shiftedDcId);
 
 	bool isNormal() const {
 		return (_mode == Instance::Mode::Normal);
@@ -147,6 +154,10 @@ private:
 	bool exportFail(const RPCError &error, mtpRequestId requestId);
 	bool onErrorDefault(mtpRequestId requestId, const RPCError &error);
 
+	Session *findSession(ShiftedDcId shiftedDcId);
+	not_null<Session*> startSession(ShiftedDcId shiftedDcId);
+	Session *removeSessionToKilled(ShiftedDcId shiftedDcId);
+
 	void applyDomainIps(
 		const QString &host,
 		const QStringList &ips,
@@ -178,18 +189,18 @@ private:
 
 	DcId _mainDcId = Config::kDefaultMainDc;
 	bool _mainDcIdForced = false;
-	std::map<DcId, std::shared_ptr<internal::Dcenter>> _dcenters;
+	base::flat_map<DcId, std::shared_ptr<Dcenter>> _dcenters;
 
 	QString _deviceModel;
 	QString _systemVersion;
 
-	internal::Session *_mainSession = nullptr;
-	std::map<ShiftedDcId, std::unique_ptr<internal::Session>> _sessions;
-	std::vector<std::unique_ptr<internal::Session>> _killedSessions; // delayed delete
+	Session *_mainSession = nullptr;
+	base::flat_map<ShiftedDcId, std::unique_ptr<Session>> _sessions;
+	std::vector<std::unique_ptr<Session>> _killedSessions; // delayed delete
 
-	base::set_of_unique_ptr<internal::Connection> _quittingConnections;
+	base::set_of_unique_ptr<Connection> _quittingConnections;
 
-	std::unique_ptr<internal::ConfigLoader> _configLoader;
+	std::unique_ptr<ConfigLoader> _configLoader;
 	std::unique_ptr<DomainResolver> _domainResolver;
 	std::unique_ptr<SpecialConfigRequest> _httpUnixtimeLoader;
 	QString _userPhone;
@@ -258,9 +269,7 @@ void Instance::Private::start(Config &&config) {
 			}
 		}
 		_keysForWrite[shiftedDcId] = key;
-
-		auto dc = std::make_shared<internal::Dcenter>(_instance, dcId, std::move(key));
-		_dcenters.emplace(shiftedDcId, std::move(dc));
+		addDc(shiftedDcId, std::move(key));
 	}
 
 	if (config.mainDcId != Config::kNotSetMainDc) {
@@ -269,17 +278,11 @@ void Instance::Private::start(Config &&config) {
 	}
 
 	if (isKeysDestroyer()) {
-		for (auto &dc : _dcenters) {
-			auto shiftedDcId = dc.first;
-			auto session = std::make_unique<internal::Session>(_instance, shiftedDcId);
-			auto it = _sessions.emplace(shiftedDcId, std::move(session)).first;
-			it->second->start();
+		for (const auto &[shiftedDcId, dc] : _dcenters) {
+			startSession(shiftedDcId);
 		}
 	} else if (_mainDcId != Config::kNoneMainDc) {
-		auto main = std::make_unique<internal::Session>(_instance, _mainDcId);
-		_mainSession = main.get();
-		_sessions.emplace(_mainDcId, std::move(main));
-		_mainSession->start();
+		_mainSession = startSession(_mainDcId);
 	}
 
 	_checkDelayedTimer.setCallback([this] { checkDelayedRequests(); });
@@ -335,8 +338,8 @@ void Instance::Private::applyDomainIps(
 	}
 	if (applyToProxy(Global::RefSelectedProxy())
 		&& (Global::ProxySettings() == ProxyData::Settings::Enabled)) {
-		for (auto &session : _sessions) {
-			session.second->refreshOptions();
+		for (const auto &[shiftedDcId, session] : _sessions) {
+			session->refreshOptions();
 		}
 	}
 	emit _instance->proxyDomainResolved(host, ips, expireAt);
@@ -398,7 +401,7 @@ void Instance::Private::requestConfig() {
 	if (_configLoader || isKeysDestroyer()) {
 		return;
 	}
-	_configLoader = std::make_unique<internal::ConfigLoader>(
+	_configLoader = std::make_unique<ConfigLoader>(
 		_instance,
 		_userPhone,
 		rpcDone([=](const MTPConfig &result) { configLoadDone(result); }),
@@ -472,16 +475,16 @@ void Instance::Private::requestCDNConfig() {
 }
 
 void Instance::Private::restart() {
-	for (auto &session : _sessions) {
-		session.second->restart();
+	for (const auto &[shiftedDcId, session] : _sessions) {
+		session->restart();
 	}
 }
 
 void Instance::Private::restart(ShiftedDcId shiftedDcId) {
-	auto dcId = BareDcId(shiftedDcId);
-	for (auto &session : _sessions) {
-		if (BareDcId(session.second->getDcWithShift()) == dcId) {
-			session.second->restart();
+	const auto dcId = BareDcId(shiftedDcId);
+	for (const auto &[shiftedDcId, session] : _sessions) {
+		if (BareDcId(shiftedDcId) == dcId) {
+			session->restart();
 		}
 	}
 }
@@ -497,11 +500,9 @@ int32 Instance::Private::dcstate(ShiftedDcId shiftedDcId) {
 		shiftedDcId += BareDcId(_mainSession->getDcWithShift());
 	}
 
-	auto it = _sessions.find(shiftedDcId);
-	if (it != _sessions.cend()) {
-		return it->second->getState();
+	if (const auto session = findSession(shiftedDcId)) {
+		return session->getState();
 	}
-
 	return DisconnectedState;
 }
 
@@ -515,11 +516,9 @@ QString Instance::Private::dctransport(ShiftedDcId shiftedDcId) {
 		shiftedDcId += BareDcId(_mainSession->getDcWithShift());
 	}
 
-	auto it = _sessions.find(shiftedDcId);
-	if (it != _sessions.cend()) {
-		return it->second->transport();
+	if (const auto session = findSession(shiftedDcId)) {
+		return session->transport();
 	}
-
 	return QString();
 }
 
@@ -563,25 +562,15 @@ int32 Instance::Private::state(mtpRequestId requestId) {
 }
 
 void Instance::Private::killSession(ShiftedDcId shiftedDcId) {
-	auto checkIfMainAndKill = [this](ShiftedDcId shiftedDcId) {
-		auto it = _sessions.find(shiftedDcId);
-		if (it != _sessions.cend()) {
-			_killedSessions.push_back(std::move(it->second));
-			_sessions.erase(it);
-			_killedSessions.back()->kill();
-			return (_killedSessions.back().get() == _mainSession);
-		}
-		return false;
+	const auto checkIfMainAndKill = [&](ShiftedDcId shiftedDcId) {
+		const auto killed = removeSessionToKilled(shiftedDcId);
+		return killed && (killed == _mainSession);
 	};
 	if (checkIfMainAndKill(shiftedDcId)) {
 		checkIfMainAndKill(_mainDcId);
-
-		auto main = std::make_unique<internal::Session>(_instance, _mainDcId);
-		_mainSession = main.get();
-		_sessions.emplace(_mainDcId, std::move(main));
-		_mainSession->start();
+		_mainSession = startSession(_mainDcId);
 	}
-	InvokeQueued(_instance, [this] {
+	InvokeQueued(_instance, [=] {
 		clearKilledSessions();
 	});
 }
@@ -591,18 +580,17 @@ void Instance::Private::clearKilledSessions() {
 }
 
 void Instance::Private::stopSession(ShiftedDcId shiftedDcId) {
-	auto it = _sessions.find(shiftedDcId);
-	if (it != _sessions.end()) {
-		if (it->second.get() != _mainSession) { // don't stop main session
-			it->second->stop();
+	if (const auto session = findSession(shiftedDcId)) {
+		if (session != _mainSession) { // don't stop main session
+			session->stop();
 		}
 	}
 }
 
 void Instance::Private::reInitConnection(DcId dcId) {
-	for (auto &session : _sessions) {
-		if (BareDcId(session.second->getDcWithShift()) == dcId) {
-			session.second->reInitConnection();
+	for (const auto &[shiftedDcId, session] : _sessions) {
+		if (BareDcId(shiftedDcId) == dcId) {
+			session->reInitConnection();
 		}
 	}
 }
@@ -647,22 +635,40 @@ bool Instance::Private::logoutGuestDone(mtpRequestId requestId) {
 	return false;
 }
 
-std::shared_ptr<internal::Dcenter> Instance::Private::getDcById(ShiftedDcId shiftedDcId) {
-	auto it = _dcenters.find(shiftedDcId);
-	if (it == _dcenters.cend()) {
-		auto dcId = BareDcId(shiftedDcId);
-		if (isTemporaryDcId(dcId)) {
-			if (auto realDcId = getRealIdFromTemporaryDcId(dcId)) {
-				dcId = realDcId;
-			}
-		}
-		it = _dcenters.find(dcId);
-		if (it == _dcenters.cend()) {
-			auto result = std::make_shared<internal::Dcenter>(_instance, dcId, AuthKeyPtr());
-			return _dcenters.emplace(dcId, std::move(result)).first->second;
+std::shared_ptr<Dcenter> Instance::Private::findDc(ShiftedDcId shiftedDcId) {
+	const auto i = _dcenters.find(shiftedDcId);
+	return (i != _dcenters.end()) ? i->second : nullptr;
+}
+
+std::shared_ptr<Dcenter> Instance::Private::addDc(
+		ShiftedDcId shiftedDcId,
+		AuthKeyPtr &&key) {
+	const auto dcId = BareDcId(shiftedDcId);
+	return _dcenters.emplace(
+		shiftedDcId,
+		std::make_shared<Dcenter>(_instance, dcId, std::move(key))
+	).first->second;
+}
+
+void Instance::Private::removeDc(ShiftedDcId shiftedDcId) {
+	_dcenters.erase(shiftedDcId);
+}
+
+std::shared_ptr<Dcenter> Instance::Private::getDcById(
+		ShiftedDcId shiftedDcId) {
+	if (auto result = findDc(shiftedDcId)) {
+		return result;
+	}
+	auto dcId = BareDcId(shiftedDcId);
+	if (isTemporaryDcId(dcId)) {
+		if (const auto realDcId = getRealIdFromTemporaryDcId(dcId)) {
+			dcId = realDcId;
 		}
 	}
-	return it->second;
+	if (auto result = findDc(dcId)) {
+		return result;
+	}
+	return addDc(dcId);
 }
 
 void Instance::Private::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
@@ -693,7 +699,7 @@ void Instance::Private::addKeysForDestroy(AuthKeysList &&keys) {
 	Expects(isKeysDestroyer());
 
 	for (auto &key : keys) {
-		auto dcId = key->dcId();
+		const auto dcId = key->dcId();
 		auto shiftedDcId = MTP::destroyKeyNextDcId(dcId);
 
 		{
@@ -706,12 +712,8 @@ void Instance::Private::addKeysForDestroy(AuthKeysList &&keys) {
 			_keysForWrite[shiftedDcId] = key;
 		}
 
-		auto dc = std::make_shared<internal::Dcenter>(_instance, dcId, std::move(key));
-		_dcenters.emplace(shiftedDcId, std::move(dc));
-
-		auto session = std::make_unique<internal::Session>(_instance, shiftedDcId);
-		auto it = _sessions.emplace(shiftedDcId, std::move(session)).first;
-		it->second->start();
+		addDc(shiftedDcId, std::move(key));
+		startSession(shiftedDcId);
 	}
 }
 
@@ -728,18 +730,18 @@ QString Instance::Private::systemVersion() const {
 }
 
 void Instance::Private::unpaused() {
-	for (auto &session : _sessions) {
-		session.second->unpaused();
+	for (const auto &[shiftedDcId, session] : _sessions) {
+		session->unpaused();
 	}
 }
 
 void Instance::Private::queueQuittingConnection(
-		std::unique_ptr<internal::Connection> &&connection) {
+		std::unique_ptr<Connection> &&connection) {
 	_quittingConnections.insert(std::move(connection));
 }
 
-void Instance::Private::connectionFinished(internal::Connection *connection) {
-	auto it = _quittingConnections.find(connection);
+void Instance::Private::connectionFinished(Connection *connection) {
+	const auto it = _quittingConnections.find(connection);
 	if (it != _quittingConnections.end()) {
 		_quittingConnections.erase(it);
 	}
@@ -1430,23 +1432,47 @@ bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &e
 	return false;
 }
 
-not_null<internal::Session*> Instance::Private::getSession(
+not_null<Session*> Instance::Private::getSession(
 		ShiftedDcId shiftedDcId) {
 	if (!shiftedDcId) {
 		Assert(_mainSession != nullptr);
 		return _mainSession;
-	}
-	if (!BareDcId(shiftedDcId)) {
+	} else if (!BareDcId(shiftedDcId)) {
 		Assert(_mainSession != nullptr);
 		shiftedDcId += BareDcId(_mainSession->getDcWithShift());
 	}
 
-	auto it = _sessions.find(shiftedDcId);
-	if (it == _sessions.cend()) {
-		it = _sessions.emplace(shiftedDcId, std::make_unique<internal::Session>(_instance, shiftedDcId)).first;
-		it->second->start();
+	if (const auto session = findSession(shiftedDcId)) {
+		return session;
 	}
-	return it->second.get();
+	return startSession(shiftedDcId);
+}
+
+Session *Instance::Private::findSession(ShiftedDcId shiftedDcId) {
+	const auto i = _sessions.find(shiftedDcId);
+	return (i != _sessions.end()) ? i->second.get() : nullptr;
+}
+
+not_null<Session*> Instance::Private::startSession(ShiftedDcId shiftedDcId) {
+	Expects(BareDcId(shiftedDcId) != 0);
+
+	const auto result = _sessions.emplace(
+		shiftedDcId,
+		std::make_unique<Session>(_instance, shiftedDcId)
+	).first->second.get();
+	result->start();
+	return result;
+}
+
+Session *Instance::Private::removeSessionToKilled(ShiftedDcId shiftedDcId) {
+	const auto i = _sessions.find(shiftedDcId);
+	if (i == _sessions.cend()) {
+		return nullptr;
+	}
+	i->second->kill();
+	_killedSessions.push_back(std::move(i->second));
+	_sessions.erase(i);
+	return _killedSessions.back().get();
 }
 
 void Instance::Private::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
@@ -1488,7 +1514,7 @@ void Instance::Private::performKeyDestroy(ShiftedDcId shiftedDcId) {
 void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 	Expects(isKeysDestroyer());
 
-	_dcenters.erase(shiftedDcId);
+	removeDc(shiftedDcId);
 	{
 		QWriteLocker lock(&_keysForWriteLock);
 		_keysForWrite.erase(shiftedDcId);
@@ -1502,7 +1528,7 @@ void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 void Instance::Private::checkMainDcKey() {
 	const auto id = mainDcId();
 	const auto shiftedDcId = ShiftDcId(id, kCheckKeyDcShift);
-	if (_sessions.find(shiftedDcId) != _sessions.end()) {
+	if (findSession(shiftedDcId)) {
 		return;
 	}
 	const auto key = [&] {
@@ -1527,9 +1553,8 @@ void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
 		}
 		restart();
 	} else {
-		const auto i = _dcenters.find(dcId);
-		if (i != end(_dcenters)) {
-			i->second->destroyKey();
+		if (const auto dc = findDc(dcId)) {
+			return dc->destroyKey();
 		}
 		restart(dcId);
 	}
@@ -1564,8 +1589,8 @@ void Instance::Private::prepareToDestroy() {
 
 	requestCancellingDiscard();
 
-	for (auto &session : base::take(_sessions)) {
-		session.second->kill();
+	for (const auto &[shiftedDcId, session] : base::take(_sessions)) {
+		session->kill();
 	}
 	_mainSession = nullptr;
 }
@@ -1632,7 +1657,7 @@ void Instance::requestCDNConfig() {
 	_private->requestCDNConfig();
 }
 
-void Instance::connectionFinished(internal::Connection *connection) {
+void Instance::connectionFinished(Connection *connection) {
 	_private->connectionFinished(connection);
 }
 
@@ -1680,7 +1705,7 @@ void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
 	_private->logout(onDone, onFail);
 }
 
-std::shared_ptr<internal::Dcenter> Instance::getDcById(ShiftedDcId shiftedDcId) {
+std::shared_ptr<Dcenter> Instance::getDcById(ShiftedDcId shiftedDcId) {
 	return _private->getDcById(shiftedDcId);
 }
 
@@ -1713,7 +1738,7 @@ void Instance::unpaused() {
 }
 
 void Instance::queueQuittingConnection(
-		std::unique_ptr<internal::Connection> &&connection) {
+		std::unique_ptr<Connection> &&connection) {
 	_private->queueQuittingConnection(std::move(connection));
 }
 
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 385c2e634..5c5c0b76f 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -143,12 +143,11 @@ void SessionData::clear(Instance *instance) {
 Session::Session(not_null<Instance*> instance, ShiftedDcId shiftedDcId)
 : QObject()
 , _instance(instance)
-, _data(this)
 , _shiftedDcId(shiftedDcId)
+, _data(this)
+, _timeouter([=] { checkRequestsByTimer(); })
 , _sender([=] { needToResumeAndSend(); }) {
-	connect(&_timeouter, SIGNAL(timeout()), this, SLOT(checkRequestsByTimer()));
-	_timeouter.start(1000);
-
+	_timeouter.callEach(1000);
 	refreshOptions();
 }
 
@@ -291,9 +290,7 @@ void Session::needToResumeAndSend() {
 	}
 	if (!_connection) {
 		DEBUG_LOG(("Session Info: resuming session dcWithShift %1").arg(_shiftedDcId));
-		createDcData();
-		_connection = std::make_unique<Connection>(_instance);
-		_connection->start(&_data, _shiftedDcId);
+		start();
 	}
 	if (_ping) {
 		_ping = false;
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index b91efbd5e..839f3c797 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -378,7 +378,6 @@ public slots:
 	void connectionWasInitedForDC();
 
 	void tryToReceive();
-	void checkRequestsByTimer();
 	void onConnectionStateChange(qint32 newState);
 	void onResetDone();
 
@@ -388,10 +387,13 @@ public slots:
 
 private:
 	void createDcData();
+	void checkRequestsByTimer();
 
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
 
-	not_null<Instance*> _instance;
+	const not_null<Instance*> _instance;
+	const ShiftedDcId _shiftedDcId = 0;
+
 	std::unique_ptr<Connection> _connection;
 
 	bool _killed = false;
@@ -399,7 +401,6 @@ private:
 
 	SessionData _data;
 
-	ShiftedDcId _shiftedDcId = 0;
 	std::shared_ptr<Dcenter> _dc;
 	AuthKeyPtr _dcKeyForCheck;
 
@@ -408,7 +409,7 @@ private:
 
 	bool _ping = false;
 
-	QTimer _timeouter;
+	base::Timer _timeouter;
 	base::Timer _sender;
 
 };

From f37ab6e38ec987210b1c5e841fa7099d74705f74 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 15 Nov 2019 09:43:44 +0300
Subject: [PATCH 15/91] Remove checked key property.

---
 Telegram/SourceFiles/mtproto/connection.cpp | 20 --------------------
 Telegram/SourceFiles/mtproto/session.h      | 10 ----------
 2 files changed, 30 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index d7e0a95bf..0a056e5f0 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -1075,22 +1075,6 @@ void ConnectionPrivate::restart() {
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
 
-	auto key = _sessionData->getKey();
-	if (key) {
-		if (!_sessionData->isCheckedKey()) {
-			// No destroying in case of an error.
-			//
-			//if (mayBeBadKey) {
-			//	clearMessages();
-			//	_keyId = kRecreateKeyId;
-//				retryTimeout = 1; // no ddos please
-			//	LOG(("MTP Info: key may be bad and was not checked - but won't be destroyed, no log outs because of bad server right now..."));
-			//}
-		} else {
-			_sessionData->setCheckedKey(false);
-		}
-	}
-
 	lockFinished.unlock();
 	doDisconnect();
 
@@ -1476,10 +1460,6 @@ void ConnectionPrivate::handleReceived() {
 		}
 		_retryTimeout = 1; // reset restart() timer
 
-		if (!_sessionData->isCheckedKey()) {
-			DEBUG_LOG(("MTP Info: marked auth key as checked"));
-			_sessionData->setCheckedKey(true);
-		}
 		_startedConnectingAt = crl::time(0);
 
 		if (!wasConnected) {
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 839f3c797..17a69272a 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -189,15 +189,6 @@ public:
 	}
 	void setKeyForCheck(const AuthKeyPtr &key);
 
-	bool isCheckedKey() const {
-		QReadLocker locker(&_lock);
-		return _keyChecked;
-	}
-	void setCheckedKey(bool checked) {
-		QWriteLocker locker(&_lock);
-		_keyChecked = checked;
-	}
-
 	QReadWriteLock *keyMutex() const;
 
 	not_null<QReadWriteLock*> toSendMutex() const {
@@ -297,7 +288,6 @@ private:
 
 	AuthKeyPtr _authKey;
 	AuthKeyPtr _dcKeyForCheck;
-	bool _keyChecked = false;
 	bool _layerInited = false;
 	ConnectionOptions _options;
 

From 055b99f5b0c01ffe03076466f694c362762e436e Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 15 Nov 2019 10:28:33 +0300
Subject: [PATCH 16/91] Don't use shared_ptr for Dcenters.

---
 Telegram/SourceFiles/core/utils.h             |   6 -
 Telegram/SourceFiles/mtproto/connection.cpp   |   9 +-
 Telegram/SourceFiles/mtproto/connection.h     |   2 -
 Telegram/SourceFiles/mtproto/dcenter.cpp      |  15 ++
 Telegram/SourceFiles/mtproto/dcenter.h        |  17 +--
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 137 ++++++++++--------
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   6 +-
 Telegram/SourceFiles/mtproto/session.cpp      |  33 ++---
 Telegram/SourceFiles/mtproto/session.h        |   8 +-
 9 files changed, 123 insertions(+), 110 deletions(-)

diff --git a/Telegram/SourceFiles/core/utils.h b/Telegram/SourceFiles/core/utils.h
index 1fb36a8c9..051ada8d2 100644
--- a/Telegram/SourceFiles/core/utils.h
+++ b/Telegram/SourceFiles/core/utils.h
@@ -25,12 +25,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace base {
 
-template <typename T>
-using set_of_unique_ptr = std::set<std::unique_ptr<T>, base::pointer_comparator<T>>;
-
-template <typename T>
-using set_of_shared_ptr = std::set<std::shared_ptr<T>, base::pointer_comparator<T>>;
-
 template <typename Value, typename From, typename Till>
 inline bool in_range(Value &&value, From &&from, Till &&till) {
 	return (value >= from) && (value < till);
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 0a056e5f0..8eecc3088 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -249,7 +249,6 @@ ConnectionPrivate::ConnectionPrivate(
 
 	connect(thread, &QThread::started, this, [=] { connectToServer(); });
 	connect(thread, &QThread::finished, this, [=] { finishAndDestroy(); });
-	connect(this, SIGNAL(finished(internal::Connection*)), _instance, SLOT(connectionFinished(internal::Connection*)), Qt::QueuedConnection);
 
 	connect(_sessionData->owner(), SIGNAL(authKeyCreated()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
 	connect(_sessionData->owner(), SIGNAL(needToRestart()), this, SLOT(restartNow()), Qt::QueuedConnection);
@@ -1227,7 +1226,11 @@ void ConnectionPrivate::doDisconnect() {
 void ConnectionPrivate::finishAndDestroy() {
 	doDisconnect();
 	_finished = true;
-	emit finished(_owner);
+	const auto connection = _owner;
+	const auto instance = _instance;
+	InvokeQueued(instance, [=] {
+		instance->connectionFinished(connection);
+	});
 	deleteLater();
 }
 
@@ -1249,7 +1252,7 @@ void ConnectionPrivate::handleReceived() {
 
 	onReceivedSome();
 
-	auto restartOnError = [this, &lockFinished] {
+	const auto restartOnError = [&] {
 		lockFinished.unlock();
 		restart();
 	};
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 912ac8fec..8a8339f98 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -94,8 +94,6 @@ signals:
 	void resendManyAsync(QVector<quint64> msgIds, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo);
 	void resendAllAsync();
 
-	void finished(internal::Connection *connection);
-
 public slots:
 	void restartNow();
 
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/dcenter.cpp
index be1fed5e6..f1ce5c769 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/dcenter.cpp
@@ -57,5 +57,20 @@ void Dcenter::destroyKey() {
 	setKey(AuthKeyPtr());
 }
 
+bool Dcenter::connectionInited() const {
+	const auto lock = QMutexLocker(&_initLock);
+	return _connectionInited;
+}
+
+void Dcenter::setConnectionInited(bool connectionInited) {
+	auto lock = QMutexLocker(&_initLock);
+	_connectionInited = connectionInited;
+	lock.unlock();
+
+	if (connectionInited) {
+		emit connectionWasInited();
+	}
+}
+
 } // namespace internal
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/dcenter.h
index d0111fcad..14e064339 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/dcenter.h
@@ -26,19 +26,8 @@ public:
 	void setKey(AuthKeyPtr &&key);
 	void destroyKey();
 
-	bool connectionInited() const {
-		QMutexLocker lock(&initLock);
-		return _connectionInited;
-	}
-	void setConnectionInited(bool connectionInited = true) {
-		QMutexLocker lock(&initLock);
-		_connectionInited = connectionInited;
-		lock.unlock();
-
-		if (connectionInited) {
-			emit connectionWasInited();
-		}
-	}
+	[[nodiscard]] bool connectionInited() const;
+	void setConnectionInited(bool connectionInited = true);
 
 signals:
 	void authKeyCreated();
@@ -49,7 +38,7 @@ private slots:
 
 private:
 	mutable QReadWriteLock keyLock;
-	mutable QMutex initLock;
+	mutable QMutex _initLock;
 	not_null<Instance*> _instance;
 	DcId _id = 0;
 	AuthKeyPtr _key;
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index cc3c37ed2..769810e00 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -81,9 +81,9 @@ public:
 	void reInitConnection(DcId dcId);
 	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
 
-	std::shared_ptr<Dcenter> getDcById(ShiftedDcId shiftedDcId);
-	std::shared_ptr<Dcenter> findDc(ShiftedDcId shiftedDcId);
-	std::shared_ptr<Dcenter> addDc(
+	not_null<Dcenter*> getDcById(ShiftedDcId shiftedDcId);
+	Dcenter *findDc(ShiftedDcId shiftedDcId);
+	not_null<Dcenter*> addDc(
 		ShiftedDcId shiftedDcId,
 		AuthKeyPtr &&key = nullptr);
 	void removeDc(ShiftedDcId shiftedDcId);
@@ -91,7 +91,7 @@ public:
 
 	void queueQuittingConnection(
 		std::unique_ptr<Connection> &&connection);
-	void connectionFinished(Connection *connection);
+	void connectionFinished(not_null<Connection*> connection);
 
 	void sendRequest(
 		mtpRequestId requestId,
@@ -138,12 +138,12 @@ public:
 	}
 
 	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
+	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
 	void performKeyDestroy(ShiftedDcId shiftedDcId);
 	void completedKeyDestroy(ShiftedDcId shiftedDcId);
 	void checkMainDcKey();
 	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
 
-	void clearKilledSessions();
 	void prepareToDestroy();
 
 private:
@@ -156,7 +156,7 @@ private:
 
 	Session *findSession(ShiftedDcId shiftedDcId);
 	not_null<Session*> startSession(ShiftedDcId shiftedDcId);
-	Session *removeSessionToKilled(ShiftedDcId shiftedDcId);
+	Session *removeSession(ShiftedDcId shiftedDcId);
 
 	void applyDomainIps(
 		const QString &host,
@@ -187,18 +187,19 @@ private:
 	const not_null<DcOptions*> _dcOptions;
 	const Instance::Mode _mode = Instance::Mode::Normal;
 
-	DcId _mainDcId = Config::kDefaultMainDc;
-	bool _mainDcIdForced = false;
-	base::flat_map<DcId, std::shared_ptr<Dcenter>> _dcenters;
-
 	QString _deviceModel;
 	QString _systemVersion;
 
+	DcId _mainDcId = Config::kDefaultMainDc;
+	bool _mainDcIdForced = false;
+	base::flat_map<DcId, std::unique_ptr<Dcenter>> _dcenters;
+	std::vector<std::unique_ptr<Dcenter>> _dcentersToDestroy;
+
 	Session *_mainSession = nullptr;
 	base::flat_map<ShiftedDcId, std::unique_ptr<Session>> _sessions;
-	std::vector<std::unique_ptr<Session>> _killedSessions; // delayed delete
+	std::vector<std::unique_ptr<Session>> _sessionsToDestroy;
 
-	base::set_of_unique_ptr<Connection> _quittingConnections;
+	std::vector<std::unique_ptr<Connection>> _connectionsToDestroy;
 
 	std::unique_ptr<ConfigLoader> _configLoader;
 	std::unique_ptr<DomainResolver> _domainResolver;
@@ -563,22 +564,20 @@ int32 Instance::Private::state(mtpRequestId requestId) {
 
 void Instance::Private::killSession(ShiftedDcId shiftedDcId) {
 	const auto checkIfMainAndKill = [&](ShiftedDcId shiftedDcId) {
-		const auto killed = removeSessionToKilled(shiftedDcId);
-		return killed && (killed == _mainSession);
+		if (const auto removed = removeSession(shiftedDcId)) {
+			return (removed == _mainSession);
+		}
+		return false;
 	};
 	if (checkIfMainAndKill(shiftedDcId)) {
 		checkIfMainAndKill(_mainDcId);
 		_mainSession = startSession(_mainDcId);
 	}
 	InvokeQueued(_instance, [=] {
-		clearKilledSessions();
+		_sessionsToDestroy.clear();
 	});
 }
 
-void Instance::Private::clearKilledSessions() {
-	_killedSessions.clear();
-}
-
 void Instance::Private::stopSession(ShiftedDcId shiftedDcId) {
 	if (const auto session = findSession(shiftedDcId)) {
 		if (session != _mainSession) { // don't stop main session
@@ -635,38 +634,47 @@ bool Instance::Private::logoutGuestDone(mtpRequestId requestId) {
 	return false;
 }
 
-std::shared_ptr<Dcenter> Instance::Private::findDc(ShiftedDcId shiftedDcId) {
+Dcenter *Instance::Private::findDc(ShiftedDcId shiftedDcId) {
 	const auto i = _dcenters.find(shiftedDcId);
-	return (i != _dcenters.end()) ? i->second : nullptr;
+	return (i != _dcenters.end()) ? i->second.get() : nullptr;
 }
 
-std::shared_ptr<Dcenter> Instance::Private::addDc(
+not_null<Dcenter*> Instance::Private::addDc(
 		ShiftedDcId shiftedDcId,
 		AuthKeyPtr &&key) {
 	const auto dcId = BareDcId(shiftedDcId);
 	return _dcenters.emplace(
 		shiftedDcId,
-		std::make_shared<Dcenter>(_instance, dcId, std::move(key))
-	).first->second;
+		std::make_unique<Dcenter>(_instance, dcId, std::move(key))
+	).first->second.get();
 }
 
 void Instance::Private::removeDc(ShiftedDcId shiftedDcId) {
-	_dcenters.erase(shiftedDcId);
+	const auto i = _dcenters.find(shiftedDcId);
+	if (i != _dcenters.end()) {
+		_dcentersToDestroy.push_back(std::move(i->second));
+		_dcenters.erase(i);
+	}
 }
 
-std::shared_ptr<Dcenter> Instance::Private::getDcById(
+not_null<Dcenter*> Instance::Private::getDcById(
 		ShiftedDcId shiftedDcId) {
-	if (auto result = findDc(shiftedDcId)) {
+	if (const auto result = findDc(shiftedDcId)) {
 		return result;
 	}
-	auto dcId = BareDcId(shiftedDcId);
-	if (isTemporaryDcId(dcId)) {
-		if (const auto realDcId = getRealIdFromTemporaryDcId(dcId)) {
-			dcId = realDcId;
+	const auto dcId = [&] {
+		const auto result = BareDcId(shiftedDcId);
+		if (isTemporaryDcId(result)) {
+			if (const auto realDcId = getRealIdFromTemporaryDcId(result)) {
+				return realDcId;
+			}
 		}
-	}
-	if (auto result = findDc(dcId)) {
 		return result;
+	}();
+	if (dcId != shiftedDcId) {
+		if (const auto result = findDc(dcId)) {
+			return result;
+		}
 	}
 	return addDc(dcId);
 }
@@ -737,13 +745,17 @@ void Instance::Private::unpaused() {
 
 void Instance::Private::queueQuittingConnection(
 		std::unique_ptr<Connection> &&connection) {
-	_quittingConnections.insert(std::move(connection));
+	_connectionsToDestroy.push_back(std::move(connection));
 }
 
-void Instance::Private::connectionFinished(Connection *connection) {
-	const auto it = _quittingConnections.find(connection);
-	if (it != _quittingConnections.end()) {
-		_quittingConnections.erase(it);
+void Instance::Private::connectionFinished(
+		not_null<Connection*> connection) {
+	const auto i = ranges::find(
+		_connectionsToDestroy,
+		connection.get(),
+		&std::unique_ptr<Connection>::get);
+	if (i != _connectionsToDestroy.end()) {
+		_connectionsToDestroy.erase(i);
 	}
 }
 
@@ -1005,7 +1017,7 @@ void Instance::Private::clearCallbacksDelayed(
 			).arg(idsString.join(", ")));
 	}
 
-	crl::on_main(_instance, [this, list = std::move(ids)] {
+	InvokeQueued(_instance, [=, list = std::move(ids)] {
 		clearCallbacks(list);
 	});
 }
@@ -1456,23 +1468,26 @@ Session *Instance::Private::findSession(ShiftedDcId shiftedDcId) {
 not_null<Session*> Instance::Private::startSession(ShiftedDcId shiftedDcId) {
 	Expects(BareDcId(shiftedDcId) != 0);
 
+	const auto dc = (GetDcIdShift(shiftedDcId) != kCheckKeyDcShift)
+		? getDcById(shiftedDcId).get()
+		: nullptr;
 	const auto result = _sessions.emplace(
 		shiftedDcId,
-		std::make_unique<Session>(_instance, shiftedDcId)
+		std::make_unique<Session>(_instance, shiftedDcId, dc)
 	).first->second.get();
 	result->start();
 	return result;
 }
 
-Session *Instance::Private::removeSessionToKilled(ShiftedDcId shiftedDcId) {
+Session *Instance::Private::removeSession(ShiftedDcId shiftedDcId) {
 	const auto i = _sessions.find(shiftedDcId);
 	if (i == _sessions.cend()) {
 		return nullptr;
 	}
 	i->second->kill();
-	_killedSessions.push_back(std::move(i->second));
+	_sessionsToDestroy.push_back(std::move(i->second));
 	_sessions.erase(i);
-	return _killedSessions.back().get();
+	return _sessionsToDestroy.back().get();
 }
 
 void Instance::Private::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
@@ -1484,13 +1499,29 @@ void Instance::Private::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
 		_instance->send(MTPauth_LogOut(), rpcDone([=](const MTPBool &) {
 			performKeyDestroy(shiftedDcId);
 		}), rpcFail([=](const RPCError &error) {
-			if (isDefaultHandledError(error)) return false;
+			if (isDefaultHandledError(error)) {
+				return false;
+			}
 			performKeyDestroy(shiftedDcId);
 			return true;
 		}), shiftedDcId);
 	}
 }
 
+void Instance::Private::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
+	InvokeQueued(_instance, [=] {
+		if (isKeysDestroyer()) {
+			LOG(("MTP Info: checkIfKeyWasDestroyed on destroying key %1, "
+				"assuming it is destroyed.").arg(shiftedDcId));
+			completedKeyDestroy(shiftedDcId);
+		} else if (BareDcId(shiftedDcId) == mainDcId()) {
+			LOG(("MTP Info: checkIfKeyWasDestroyed for main dc %1, "
+				"checking.").arg(shiftedDcId));
+			checkMainDcKey();
+		}
+	});
+}
+
 void Instance::Private::performKeyDestroy(ShiftedDcId shiftedDcId) {
 	Expects(isKeysDestroyer());
 
@@ -1657,7 +1688,7 @@ void Instance::requestCDNConfig() {
 	_private->requestCDNConfig();
 }
 
-void Instance::connectionFinished(Connection *connection) {
+void Instance::connectionFinished(not_null<Connection*> connection) {
 	_private->connectionFinished(connection);
 }
 
@@ -1705,10 +1736,6 @@ void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
 	_private->logout(onDone, onFail);
 }
 
-std::shared_ptr<Dcenter> Instance::getDcById(ShiftedDcId shiftedDcId) {
-	return _private->getDcById(shiftedDcId);
-}
-
 void Instance::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
 	_private->setKeyForWrite(dcId, key);
 }
@@ -1799,17 +1826,7 @@ void Instance::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
 }
 
 void Instance::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
-	crl::on_main(this, [=] {
-		if (isKeysDestroyer()) {
-			LOG(("MTP Info: checkIfKeyWasDestroyed on destroying key %1, "
-				"assuming it is destroyed.").arg(shiftedDcId));
-			_private->completedKeyDestroy(shiftedDcId);
-		} else if (BareDcId(shiftedDcId) == mainDcId()) {
-			LOG(("MTP Info: checkIfKeyWasDestroyed for main dc %1, "
-				"checking.").arg(shiftedDcId));
-			_private->checkMainDcKey();
-		}
-	});
+	_private->checkIfKeyWasDestroyed(shiftedDcId);
 }
 
 void Instance::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 25ce04ac2..2fdbdf23f 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -149,7 +149,6 @@ public:
 	void reInitConnection(DcId dcId);
 	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
 
-	std::shared_ptr<internal::Dcenter> getDcById(ShiftedDcId shiftedDcId);
 	void unpaused();
 
 	void queueQuittingConnection(std::unique_ptr<internal::Connection> &&connection);
@@ -185,10 +184,9 @@ public:
 
 	void syncHttpUnixtime();
 
-	~Instance();
+	void connectionFinished(not_null<internal::Connection*> connection);
 
-public slots:
-	void connectionFinished(internal::Connection *connection);
+	~Instance();
 
 signals:
 	void configLoaded();
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 5c5c0b76f..709ebf1ff 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -140,19 +140,32 @@ void SessionData::clear(Instance *instance) {
 	instance->clearCallbacksDelayed(std::move(clearCallbacks));
 }
 
-Session::Session(not_null<Instance*> instance, ShiftedDcId shiftedDcId)
+Session::Session(
+	not_null<Instance*> instance,
+	ShiftedDcId shiftedDcId,
+	Dcenter *dc)
 : QObject()
 , _instance(instance)
 , _shiftedDcId(shiftedDcId)
+, _dc(dc)
 , _data(this)
 , _timeouter([=] { checkRequestsByTimer(); })
 , _sender([=] { needToResumeAndSend(); }) {
 	_timeouter.callEach(1000);
 	refreshOptions();
+	if (_dc) {
+		if (const auto lock = ReadLockerAttempt(keyMutex())) {
+			_data.setKey(_dc->getKey());
+			if (_dc->connectionInited()) {
+				_data.setConnectionInited();
+			}
+		}
+		connect(_dc, SIGNAL(authKeyCreated()), this, SLOT(authKeyCreatedForDC()), Qt::QueuedConnection);
+		connect(_dc, SIGNAL(connectionWasInited()), this, SLOT(connectionWasInitedForDC()), Qt::QueuedConnection);
+	}
 }
 
 void Session::start() {
-	createDcData();
 	_connection = std::make_unique<Connection>(_instance);
 	_connection->start(&_data, _shiftedDcId);
 	if (_instance->isKeysDestroyer()) {
@@ -160,22 +173,6 @@ void Session::start() {
 	}
 }
 
-void Session::createDcData() {
-	if (_dc || GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift) {
-		return;
-	}
-	_dc = _instance->getDcById(_shiftedDcId);
-
-	if (auto lock = ReadLockerAttempt(keyMutex())) {
-		_data.setKey(_dc->getKey());
-		if (_dc->connectionInited()) {
-			_data.setConnectionInited();
-		}
-	}
-	connect(_dc.get(), SIGNAL(authKeyCreated()), this, SLOT(authKeyCreatedForDC()), Qt::QueuedConnection);
-	connect(_dc.get(), SIGNAL(connectionWasInited()), this, SLOT(connectionWasInitedForDC()), Qt::QueuedConnection);
-}
-
 bool Session::rpcErrorOccured(
 		mtpRequestId requestId,
 		const RPCFailHandlerPtr &onFail,
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 17a69272a..536998bd8 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -317,7 +317,10 @@ class Session : public QObject {
 	Q_OBJECT
 
 public:
-	Session(not_null<Instance*> instance, ShiftedDcId shiftedDcId);
+	Session(
+		not_null<Instance*> instance,
+		ShiftedDcId shiftedDcId,
+		Dcenter *dc);
 
 	void start();
 	void restart();
@@ -376,13 +379,13 @@ public slots:
 	void sendMsgsStateInfo(quint64 msgId, QByteArray data);
 
 private:
-	void createDcData();
 	void checkRequestsByTimer();
 
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
 
 	const not_null<Instance*> _instance;
 	const ShiftedDcId _shiftedDcId = 0;
+	Dcenter *_dc = nullptr;
 
 	std::unique_ptr<Connection> _connection;
 
@@ -391,7 +394,6 @@ private:
 
 	SessionData _data;
 
-	std::shared_ptr<Dcenter> _dc;
 	AuthKeyPtr _dcKeyForCheck;
 
 	crl::time _msSendCall = 0;

From be06d68468bcb9d8e67091e53b290b27117e46fd Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 15 Nov 2019 16:04:32 +0300
Subject: [PATCH 17/91] Don't lock whole key creation by a mutex.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 262 ++++++++----------
 Telegram/SourceFiles/mtproto/connection.h     |  30 +-
 .../SourceFiles/mtproto/connection_abstract.h |  10 +-
 Telegram/SourceFiles/mtproto/dcenter.cpp      |  86 ++++--
 Telegram/SourceFiles/mtproto/dcenter.h        |  33 ++-
 .../details/mtproto_dc_key_creator.cpp        |  36 +--
 .../mtproto/details/mtproto_dc_key_creator.h  |   1 +
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  27 +-
 Telegram/SourceFiles/mtproto/mtp_instance.h   | 117 ++++----
 Telegram/SourceFiles/mtproto/rpc_sender.h     |   6 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 140 +++++-----
 Telegram/SourceFiles/mtproto/session.h        |  94 ++-----
 12 files changed, 397 insertions(+), 445 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 8eecc3088..d5328d9d7 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -40,7 +40,6 @@ namespace MTP {
 namespace internal {
 namespace {
 
-constexpr auto kRecreateKeyId = AuthKey::KeyId(0xFFFFFFFFFFFFFFFFULL);
 constexpr auto kIntSize = static_cast<int>(sizeof(mtpPrime));
 constexpr auto kWaitForBetterTimeout = crl::time(2000);
 constexpr auto kMinConnectedTimeout = crl::time(1000);
@@ -100,6 +99,14 @@ Connection::Connection(not_null<Instance*> instance)
 : _instance(instance) {
 }
 
+Connection::~Connection() {
+	Expects(_private == nullptr);
+
+	if (_thread) {
+		waitTillFinish();
+	}
+}
+
 void Connection::start(SessionData *sessionData, ShiftedDcId shiftedDcId) {
 	Expects(_thread == nullptr && _private == nullptr);
 
@@ -144,14 +151,6 @@ QString Connection::transport() const {
 	return _private->transport();
 }
 
-Connection::~Connection() {
-	Expects(_private == nullptr);
-
-	if (_thread) {
-		waitTillFinish();
-	}
-}
-
 void ConnectionPrivate::appendTestConnection(
 		DcOptions::Variants::Protocol protocol,
 		const QString &ip,
@@ -215,11 +214,14 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 }
 
 void ConnectionPrivate::destroyAllConnections() {
+	{
+		QReadLocker lockFinished(&_sessionDataMutex);
+		clearKeyCreatorOnFail();
+	}
 	_waitForBetterTimer.cancel();
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
 	_testConnections.clear();
-	_keyCreator = nullptr;
 	_connection = nullptr;
 }
 
@@ -250,7 +252,7 @@ ConnectionPrivate::ConnectionPrivate(
 	connect(thread, &QThread::started, this, [=] { connectToServer(); });
 	connect(thread, &QThread::finished, this, [=] { finishAndDestroy(); });
 
-	connect(_sessionData->owner(), SIGNAL(authKeyCreated()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
+	connect(_sessionData->owner(), SIGNAL(authKeyChanged()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
 	connect(_sessionData->owner(), SIGNAL(needToRestart()), this, SLOT(restartNow()), Qt::QueuedConnection);
 	connect(this, SIGNAL(needToReceive()), _sessionData->owner(), SLOT(tryToReceive()), Qt::QueuedConnection);
 	connect(this, SIGNAL(stateChanged(qint32)), _sessionData->owner(), SLOT(onConnectionStateChange(qint32)), Qt::QueuedConnection);
@@ -274,6 +276,13 @@ ConnectionPrivate::ConnectionPrivate(
 	connect(this, SIGNAL(resendAllAsync()), _sessionData->owner(), SLOT(resendAll()), Qt::QueuedConnection);
 }
 
+ConnectionPrivate::~ConnectionPrivate() {
+	Expects(_finished);
+	Expects(!_connection);
+	Expects(_testConnections.empty());
+	Expects(!_keyCreator);
+}
+
 void ConnectionPrivate::onConfigLoaded() {
 	connectToServer(true);
 }
@@ -562,11 +571,11 @@ mtpMsgId ConnectionPrivate::placeToContainer(SecureRequest &toSendRequest, mtpMs
 
 void ConnectionPrivate::tryToSend() {
 	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData || !_connection) {
+	if (!_sessionData || !_connection || !_keyId) {
 		return;
 	}
 
-	auto needsLayer = !_connectionOptions->inited;
+	auto needsLayer = !_sessionData->owner()->connectionInited();
 	auto state = getState();
 	auto sendOnlyFirstPing = (state != ConnectedState);
 	if (sendOnlyFirstPing && !_pingIdToSend) {
@@ -650,7 +659,7 @@ void ConnectionPrivate::tryToSend() {
 					_shiftedDcId,
 					keyForCheck);
 				checkDcKeyRequest = _keyChecker->prepareRequest(
-					_sessionData->getKey(),
+					_key,
 					_sessionData->getSessionId());
 
 				// This is a special request with msgId used inside the message
@@ -771,7 +780,9 @@ void ConnectionPrivate::tryToSend() {
 					auto &haveSent = _sessionData->haveSentMap();
 					haveSent.insert(msgId, toSendRequest);
 
-					if (needsLayer && !toSendRequest->needsLayer) needsLayer = false;
+					if (needsLayer && !toSendRequest->needsLayer) {
+						needsLayer = false;
+					}
 					if (toSendRequest->after) {
 						const auto toSendSize = tl::count_length(toSendRequest) >> 2;
 						auto wrappedRequest = SecureRequest::Prepare(
@@ -844,6 +855,7 @@ void ConnectionPrivate::tryToSend() {
 
 			// prepare "request-like" wrap for msgId vector
 			auto haveSentIdsWrap = SecureRequest::Prepare(idsWrapSize);
+			haveSentIdsWrap->msDate = 0; // Container: msDate = 0, seqNo = 0.
 			haveSentIdsWrap->requestId = 0;
 			haveSentIdsWrap->resize(haveSentIdsWrap->size() + idsWrapSize);
 			auto haveSentArr = (mtpMsgId*)(haveSentIdsWrap->data() + 8);
@@ -931,15 +943,6 @@ void ConnectionPrivate::retryByTimer() {
 	} else if (_retryTimeout < 64000) {
 		_retryTimeout *= 2;
 	}
-	if (_keyId == kRecreateKeyId) {
-		if (_sessionData->getKey()) {
-			unlockKey();
-
-			QWriteLocker lock(_sessionData->keyMutex());
-			_sessionData->owner()->destroyKey();
-		}
-		_keyId = 0;
-	}
 	connectToServer();
 }
 
@@ -964,7 +967,8 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 	}
 	_connectionOptions = std::make_unique<ConnectionOptions>(
 		_sessionData->connectionOptions());
-	const auto hasKey = (_sessionData->getKey() != nullptr);
+	// #TODO race.
+	const auto hasKey = (_sessionData->owner()->getKey() != nullptr);
 	lockFinished.unlock();
 
 	const auto bareDc = BareDcId(_shiftedDcId);
@@ -1212,13 +1216,6 @@ void ConnectionPrivate::connectingTimedOut() {
 void ConnectionPrivate::doDisconnect() {
 	destroyAllConnections();
 
-	{
-		QReadLocker lockFinished(&_sessionDataMutex);
-		if (_sessionData) {
-			unlockKey();
-		}
-	}
-
 	setState(DisconnectedState);
 	_restarted = false;
 }
@@ -1257,21 +1254,6 @@ void ConnectionPrivate::handleReceived() {
 		restart();
 	};
 
-	ReadLockerAttempt lock(_sessionData->keyMutex());
-	if (!lock) {
-		DEBUG_LOG(("MTP Error: auth_key for dc %1 busy, cant lock").arg(_shiftedDcId));
-		clearMessages();
-		_keyId = 0;
-
-		return restartOnError();
-	}
-
-	auto key = _sessionData->getKey();
-	if (!key || key->keyId() != _keyId) {
-		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
-		return restartOnError();
-	}
-
 	while (!_connection->received().empty()) {
 		auto intsBuffer = std::move(_connection->received().front());
 		_connection->received().pop_front();
@@ -1302,9 +1284,9 @@ void ConnectionPrivate::handleReceived() {
 		auto msgKey = *(MTPint128*)(ints + 2);
 
 #ifdef TDESKTOP_MTPROTO_OLD
-		aesIgeDecrypt_oldmtp(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, key, msgKey);
+		aesIgeDecrypt_oldmtp(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _key, msgKey);
 #else // TDESKTOP_MTPROTO_OLD
-		aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, key, msgKey);
+		aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _key, msgKey);
 #endif // TDESKTOP_MTPROTO_OLD
 
 		auto decryptedInts = reinterpret_cast<const mtpPrime*>(decryptedBuffer.constData());
@@ -1351,7 +1333,7 @@ void ConnectionPrivate::handleReceived() {
 
 		SHA256_CTX msgKeyLargeContext;
 		SHA256_Init(&msgKeyLargeContext);
-		SHA256_Update(&msgKeyLargeContext, key->partForMsgKey(false), 32);
+		SHA256_Update(&msgKeyLargeContext, _key->partForMsgKey(false), 32);
 		SHA256_Update(&msgKeyLargeContext, decryptedInts, encryptedBytesCount);
 		SHA256_Final(sha256Buffer.data(), &msgKeyLargeContext);
 
@@ -1960,10 +1942,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			// An error could be some RPC_CALL_FAIL or other error inside
 			// the initConnection, so we're not sure yet that it was inited.
 			// Wait till a good response is received.
-			if (!_connectionOptions->inited) {
-				_connectionOptions->inited = true;
-				_sessionData->notifyConnectionInited(*_connectionOptions);
-			}
+			_sessionData->notifyConnectionInited(*_connectionOptions);
 		}
 
 		if (_keyChecker && _keyChecker->handleResponse(reqMsgId, response)) {
@@ -2346,7 +2325,7 @@ void ConnectionPrivate::onConnected(
 		_testConnections.clear();
 
 		lockFinished.unlock();
-		updateAuthKey();
+		checkAuthKey();
 	}
 }
 
@@ -2383,7 +2362,7 @@ void ConnectionPrivate::confirmBestConnection() {
 	_connection = std::move(i->data);
 	_testConnections.clear();
 
-	updateAuthKey();
+	checkAuthKey();
 }
 
 void ConnectionPrivate::removeTestConnection(
@@ -2396,51 +2375,58 @@ void ConnectionPrivate::removeTestConnection(
 		end(_testConnections));
 }
 
+void ConnectionPrivate::checkAuthKey() {
+	if (!_keyId) {
+		updateAuthKey();
+	} else {
+		authKeyChecked();
+	}
+}
+
 void ConnectionPrivate::updateAuthKey() {
 	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData || !_connection) {
+	if (!_sessionData || _keyCreator) {
 		return;
 	}
 
 	DEBUG_LOG(("AuthKey Info: Connection updating key from Session, dc %1").arg(_shiftedDcId));
-	uint64 newKeyId = 0;
-	{
-		ReadLockerAttempt lock(_sessionData->keyMutex());
-		if (!lock) {
-			DEBUG_LOG(("MTP Info: could not lock auth_key for read, waiting signal emit"));
-			clearMessages();
-			_keyId = newKeyId;
-			return; // some other connection is getting key
+	_key = _sessionData->owner()->getKey();
+	const auto newKeyId = _key ? _key->keyId() : 0;
+	if (newKeyId) {
+		if (_keyId == newKeyId) {
+			return;
 		}
-		auto key = _sessionData->getKey();
-		newKeyId = key ? key->keyId() : 0;
+		_sessionData->setCurrentKeyId(newKeyId);
 	}
-	if (_keyId != newKeyId) {
-		clearMessages();
-		_keyId = newKeyId;
+	_keyId = newKeyId;
+	if (!_connection) {
+		return;
+	}
+	if (const auto already = _connection->sentEncryptedWithKeyId()) {
+		Assert(already != newKeyId);
+		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
+
+		lockFinished.unlock();
+		restart();
+		return;
 	}
 	DEBUG_LOG(("AuthKey Info: Connection update key from Session, dc %1 result: %2").arg(_shiftedDcId).arg(Logs::mb(&_keyId, sizeof(_keyId)).str()));
 	if (_keyId) {
-		return authKeyCreated();
+		return authKeyChecked();
 	}
 
-	DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), will be creating auth_key"));
-	lockKey();
-
-	const auto &key = _sessionData->getKey();
-	if (key) {
-		if (_keyId != key->keyId()) clearMessages();
-		_keyId = key->keyId();
-		unlockKey();
-		return authKeyCreated();
-	} else if (_instance->isKeysDestroyer()) {
+	if (_instance->isKeysDestroyer()) {
 		// We are here to destroy an old key, so we're done.
 		LOG(("MTP Error: No key %1 in updateAuthKey() for destroying.").arg(_shiftedDcId));
 		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
 		return;
+	} else if (!_sessionData->owner()->acquireKeyCreation()) {
+		DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), but someone is creating already."));
+		return;
 	}
 	lockFinished.unlock();
 
+	DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), creating."));
 	createDcKey();
 }
 
@@ -2449,23 +2435,24 @@ void ConnectionPrivate::createDcKey() {
 	using Error = DcKeyCreator::Error;
 	auto delegate = DcKeyCreator::Delegate();
 	delegate.done = [=](base::expected<Result, Error> result) {
-		_keyCreator = nullptr;
+		QReadLocker lockFinished(&_sessionDataMutex);
+		if (!_sessionData) return;
 
 		if (result) {
-			QReadLocker lockFinished(&_sessionDataMutex);
-			if (!_sessionData) return;
+			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(result->key->keyId()).arg(result->serverSalt));
 
 			_sessionData->setSalt(result->serverSalt);
+			_sessionData->clearForNewKey(_instance);
 
-			auto authKey = std::move(result->key);
+			_keyCreator = nullptr;
+			_sessionData->owner()->releaseKeyCreationOnDone(
+				std::move(result->key));
 
-			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(authKey->keyId()).arg(result->serverSalt));
-
-			// slot will call authKeyCreated().
-			_sessionData->owner()->notifyKeyCreated(std::move(authKey));
-			_sessionData->clear(_instance);
-			unlockKey();
-		} else if (result.error() == Error::UnknownPublicKey) {
+			updateAuthKey();
+			return;
+		}
+		clearKeyCreatorOnFail();
+		if (result.error() == Error::UnknownPublicKey) {
 			if (_dcType == DcType::Cdn) {
 				LOG(("Warning: CDN public RSA key not found"));
 				requestCDNConfig();
@@ -2489,26 +2476,18 @@ void ConnectionPrivate::createDcKey() {
 		expireIn);
 }
 
-void ConnectionPrivate::clearMessages() {
-	if (_keyId && _keyId != kRecreateKeyId && _connection) {
-		_connection->received().clear();
-	}
-}
-
-void ConnectionPrivate::authKeyCreated() {
-	_keyCreator = nullptr;
-
+void ConnectionPrivate::authKeyChecked() {
 	connect(_connection, &AbstractConnection::receivedData, [=] {
 		handleReceived();
 	});
 
-	if (_sessionData->getSalt()) { // else receive salt in bad_server_salt first, then try to send all the requests
+	if (_sessionData->getSalt()) {
 		setState(ConnectedState);
 		if (_restarted) {
 			emit resendAllAsync();
 			_restarted = false;
 		}
-	}
+	} // else receive salt in bad_server_salt first, then try to send all the requests
 
 	_pingIdToSend = rand_value<uint64>(); // get server_salt
 
@@ -2542,8 +2521,7 @@ void ConnectionPrivate::handleError(int errorCode) {
 	if (errorCode == -404) {
 		if (_dcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
 			LOG(("MTP Info: -404 error received in CDN dc %1, assuming it was destroyed, recreating.").arg(_shiftedDcId));
-			clearMessages();
-			_keyId = kRecreateKeyId;
+			destroyCdnKey();
 			return restart();
 		} else {
 			LOG(("MTP Info: -404 error received, informing instance."));
@@ -2557,7 +2535,16 @@ void ConnectionPrivate::handleError(int errorCode) {
 	return restart();
 }
 
-void ConnectionPrivate::onReadyData() {
+void ConnectionPrivate::destroyCdnKey() {
+	if (_key) {
+		QReadLocker lockFinished(&_sessionDataMutex);
+		if (_sessionData) {
+			_sessionData->owner()->destroyCdnKey(_keyId);
+		}
+	}
+	_key = nullptr;
+	_keyId = 0;
+
 }
 
 bool ConnectionPrivate::sendSecureRequest(
@@ -2581,24 +2568,6 @@ bool ConnectionPrivate::sendSecureRequest(
 		return false;
 	}
 
-	auto lock = ReadLockerAttempt(_sessionData->keyMutex());
-	if (!lock) {
-		DEBUG_LOG(("MTP Info: could not lock key for read in sendBuffer(), dc %1, restarting...").arg(_shiftedDcId));
-
-		lockFinished.unlock();
-		restart();
-		return false;
-	}
-
-	auto key = _sessionData->getKey();
-	if (!key || key->keyId() != _keyId) {
-		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
-
-		lockFinished.unlock();
-		restart();
-		return false;
-	}
-
 	auto session = _sessionData->getSessionId();
 	auto salt = _sessionData->getSalt();
 
@@ -2626,7 +2595,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		request->constData(),
 		&packet[prefix],
 		fullSize * sizeof(mtpPrime),
-		key,
+		_key,
 		msgKey);
 #else // TDESKTOP_MTPROTO_OLD
 	uchar encryptedSHA256[32];
@@ -2634,7 +2603,7 @@ bool ConnectionPrivate::sendSecureRequest(
 
 	SHA256_CTX msgKeyLargeContext;
 	SHA256_Init(&msgKeyLargeContext);
-	SHA256_Update(&msgKeyLargeContext, key->partForMsgKey(true), 32);
+	SHA256_Update(&msgKeyLargeContext, _key->partForMsgKey(true), 32);
 	SHA256_Update(&msgKeyLargeContext, request->constData(), fullSize * sizeof(mtpPrime));
 	SHA256_Final(encryptedSHA256, &msgKeyLargeContext);
 
@@ -2646,13 +2615,13 @@ bool ConnectionPrivate::sendSecureRequest(
 		request->constData(),
 		&packet[prefix],
 		fullSize * sizeof(mtpPrime),
-		key,
+		_key,
 		msgKey);
 #endif // TDESKTOP_MTPROTO_OLD
 
 	DEBUG_LOG(("MTP Info: sending request, size: %1, num: %2, time: %3").arg(fullSize + 6).arg((*request)[4]).arg((*request)[5]));
 
-	_connection->setSentEncrypted();
+	_connection->setSentEncryptedWithKeyId(_keyId);
 	_connection->sendData(std::move(packet));
 
 	if (needAnyResponse) {
@@ -2689,39 +2658,24 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 	return 0;
 }
 
-void ConnectionPrivate::lockKey() {
-	unlockKey();
-	if (const auto mutex = _sessionData->keyMutex()) {
-		mutex->lockForWrite();
-	}
-	_myKeyLock = true;
-}
+// _sessionDataMutex must be locked for read.
+void ConnectionPrivate::clearKeyCreatorOnFail() {
+	if (_keyCreator) {
+		_keyCreator = nullptr;
 
-void ConnectionPrivate::unlockKey() {
-	if (_myKeyLock) {
-		_myKeyLock = false;
-		if (const auto mutex = _sessionData->keyMutex()) {
-			mutex->unlock();
-		}
+		Assert(_sessionData != nullptr);
+		_sessionData->owner()->releaseKeyCreationOnFail();
 	}
 }
 
-ConnectionPrivate::~ConnectionPrivate() {
-	Expects(_finished);
-	Expects(!_connection);
-	Expects(_testConnections.empty());
-	Expects(!_keyCreator);
-}
-
 void ConnectionPrivate::stop() {
 	QWriteLocker lockFinished(&_sessionDataMutex);
-	if (_sessionData) {
-		if (_myKeyLock) {
-			_sessionData->owner()->notifyKeyCreated(AuthKeyPtr()); // release key lock, let someone else create it
-			unlockKey();
-		}
-		_sessionData = nullptr;
+	if (!_sessionData) {
+		Assert(_keyCreator == nullptr);
+		return;
 	}
+	clearKeyCreatorOnFail();
+	_sessionData = nullptr;
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 8a8339f98..8a6084474 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -41,12 +41,12 @@ public:
 	};
 
 	Connection(not_null<Instance*> instance);
+	~Connection();
 
 	void start(SessionData *data, ShiftedDcId shiftedDcId);
 
 	void kill();
 	void waitTillFinish();
-	~Connection();
 
 	static const int UpdateAlways = 666;
 
@@ -99,14 +99,6 @@ public slots:
 
 	void onPingSendForce();
 
-	void onSentSome(uint64 size);
-	void onReceivedSome();
-
-	void onReadyData();
-
-	// General packet receive slot, connected to conn->receivedData signal
-	void handleReceived();
-
 	// Sessions signals, when we need to send something
 	void tryToSend();
 
@@ -132,6 +124,10 @@ private:
 		qint32 errorCode);
 	void onConnected(not_null<AbstractConnection*> connection);
 	void onDisconnected(not_null<AbstractConnection*> connection);
+	void onSentSome(uint64 size);
+	void onReceivedSome();
+
+	void handleReceived();
 
 	void retryByTimer();
 	void waitConnectedFailed();
@@ -140,7 +136,9 @@ private:
 	void markConnectionOld();
 	void sendPingByTimer();
 
+	// Locks _sessionDataMutex.
 	void destroyAllConnections();
+
 	void confirmBestConnection();
 	void removeTestConnection(not_null<AbstractConnection*> connection);
 	int16 getProtocolDcId() const;
@@ -170,8 +168,6 @@ private:
 	mtpBuffer ungzip(const mtpPrime *from, const mtpPrime *end) const;
 	void handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked);
 
-	void clearMessages();
-
 	bool setState(int32 state, int32 ifState = Connection::UpdateAlways);
 
 	void appendTestConnection(
@@ -191,9 +187,12 @@ private:
 
 	void createDcKey();
 	void resetSession();
-	void lockKey();
-	void unlockKey();
-	void authKeyCreated();
+	void checkAuthKey();
+	void authKeyChecked();
+	void destroyCdnKey();
+
+	// _sessionDataMutex must be locked for read.
+	void clearKeyCreatorOnFail();
 
 	not_null<Instance*> _instance;
 	DcType _dcType = DcType::Regular;
@@ -235,13 +234,12 @@ private:
 	bool _restarted = false;
 	bool _finished = false;
 
+	AuthKeyPtr _key;
 	uint64 _keyId = 0;
 	QReadWriteLock _sessionDataMutex;
 	SessionData *_sessionData = nullptr;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 
-	bool _myKeyLock = false;
-
 	std::unique_ptr<details::DcKeyCreator> _keyCreator;
 	std::unique_ptr<details::DcKeyChecker> _keyChecker;
 
diff --git a/Telegram/SourceFiles/mtproto/connection_abstract.h b/Telegram/SourceFiles/mtproto/connection_abstract.h
index 802f9fbd9..b84ae0d08 100644
--- a/Telegram/SourceFiles/mtproto/connection_abstract.h
+++ b/Telegram/SourceFiles/mtproto/connection_abstract.h
@@ -100,8 +100,11 @@ public:
 	[[nodiscard]] virtual QString transport() const = 0;
 	[[nodiscard]] virtual QString tag() const = 0;
 
-	void setSentEncrypted() {
-		_sentEncrypted = true;
+	void setSentEncryptedWithKeyId(uint64 keyId) {
+		_sentEncryptedWithKeyId = keyId;
+	}
+	[[nodiscard]] uint64 sentEncryptedWithKeyId() const {
+		return _sentEncryptedWithKeyId;
 	}
 
 	using BuffersQueue = std::deque<mtpBuffer>;
@@ -137,7 +140,6 @@ signals:
 
 protected:
 	BuffersQueue _receivedQueue; // list of received packets, not processed yet
-	bool _sentEncrypted = false;
 	int _pingTime = 0;
 	ProxyData _proxy;
 
@@ -150,6 +152,8 @@ protected:
 private:
 	[[nodiscard]] uint32 extendedNotSecurePadding() const;
 
+	uint64 _sentEncryptedWithKeyId = 0;
+
 };
 
 template <typename Request>
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/dcenter.cpp
index f1ce5c769..970ca3f39 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/dcenter.cpp
@@ -23,53 +23,81 @@ constexpr auto kSpecialRequestTimeoutMs = 6000; // 4 seconds timeout for it to w
 
 } // namespace
 
-Dcenter::Dcenter(not_null<Instance*> instance, DcId dcId, AuthKeyPtr &&key)
-: _instance(instance)
-, _id(dcId)
+Dcenter::Dcenter(DcId dcId, AuthKeyPtr &&key)
+: _id(dcId)
 , _key(std::move(key)) {
-	connect(this, SIGNAL(authKeyCreated()), this, SLOT(authKeyWrite()), Qt::QueuedConnection);
 }
 
-void Dcenter::authKeyWrite() {
-	DEBUG_LOG(("AuthKey Info: MTProtoDC::authKeyWrite() slot, dc %1").arg(_id));
-	if (_key) {
-		Local::writeMtpData();
-	}
+DcId Dcenter::id() const {
+	return _id;
 }
 
-void Dcenter::setKey(AuthKeyPtr &&key) {
-	DEBUG_LOG(("AuthKey Info: MTProtoDC::setKey(%1), emitting authKeyCreated, dc %2").arg(key ? key->keyId() : 0).arg(_id));
-	_key = std::move(key);
-	_connectionInited = false;
-	_instance->setKeyForWrite(_id, _key);
-	emit authKeyCreated();
-}
-
-QReadWriteLock *Dcenter::keyMutex() const {
-	return &keyLock;
-}
-
-const AuthKeyPtr &Dcenter::getKey() const {
+AuthKeyPtr Dcenter::getKey() const {
+	QReadLocker lock(&_mutex);
 	return _key;
 }
 
-void Dcenter::destroyKey() {
-	setKey(AuthKeyPtr());
+void Dcenter::destroyCdnKey(uint64 keyId) {
+	destroyKey(keyId);
+}
+
+bool Dcenter::destroyConfirmedForgottenKey(uint64 keyId) {
+	return destroyKey(keyId);
+}
+
+bool Dcenter::destroyKey(uint64 keyId) {
+	Expects(!_creatingKey || !_key);
+
+	QWriteLocker lock(&_mutex);
+	if (_key->keyId() != keyId) {
+		return false;
+	}
+	_key = nullptr;
+	_connectionInited = false;
+	lock.unlock();
+
+	emit authKeyChanged();
+	return true;
 }
 
 bool Dcenter::connectionInited() const {
-	const auto lock = QMutexLocker(&_initLock);
+	QReadLocker lock(&_mutex);
 	return _connectionInited;
 }
 
 void Dcenter::setConnectionInited(bool connectionInited) {
-	auto lock = QMutexLocker(&_initLock);
+	QWriteLocker lock(&_mutex);
 	_connectionInited = connectionInited;
+}
+
+bool Dcenter::acquireKeyCreation() {
+	QReadLocker lock(&_mutex);
+	if (_key != nullptr) {
+		return false;
+	}
+	auto expected = false;
+	return _creatingKey.compare_exchange_strong(expected, true);
+}
+
+void Dcenter::releaseKeyCreationOnFail() {
+	Expects(_creatingKey);
+	Expects(_key == nullptr);
+
+	_creatingKey = false;
+}
+
+void Dcenter::releaseKeyCreationOnDone(AuthKeyPtr &&key) {
+	Expects(_creatingKey);
+	Expects(_key == nullptr);
+
+	QWriteLocker lock(&_mutex);
+	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1), emitting authKeyChanged, dc %2").arg(key ? key->keyId() : 0).arg(_id));
+	_key = std::move(key);
+	_connectionInited = false;
+	_creatingKey = false;
 	lock.unlock();
 
-	if (connectionInited) {
-		emit connectionWasInited();
-	}
+	emit authKeyChanged();
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/dcenter.h
index 14e064339..002762b1c 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/dcenter.h
@@ -19,30 +19,35 @@ class Dcenter : public QObject {
 	Q_OBJECT
 
 public:
-	Dcenter(not_null<Instance*> instance, DcId dcId, AuthKeyPtr &&key);
+	// Main thread.
+	Dcenter(DcId dcId, AuthKeyPtr &&key);
 
-	QReadWriteLock *keyMutex() const;
-	const AuthKeyPtr &getKey() const;
-	void setKey(AuthKeyPtr &&key);
-	void destroyKey();
+	// Thread-safe.
+	[[nodiscard]] DcId id() const;
+
+	[[nodiscard]] AuthKeyPtr getKey() const;
+	void destroyCdnKey(uint64 keyId);
+	bool destroyConfirmedForgottenKey(uint64 keyId);
+	void releaseKeyCreationOnDone(AuthKeyPtr &&key);
 
 	[[nodiscard]] bool connectionInited() const;
 	void setConnectionInited(bool connectionInited = true);
 
-signals:
-	void authKeyCreated();
-	void connectionWasInited();
+	[[nodiscard]] bool acquireKeyCreation();
+	void releaseKeyCreationOnFail();
 
-private slots:
-	void authKeyWrite();
+signals:
+	void authKeyChanged();
 
 private:
-	mutable QReadWriteLock keyLock;
-	mutable QMutex _initLock;
-	not_null<Instance*> _instance;
-	DcId _id = 0;
+	bool destroyKey(uint64 keyId);
+
+	const DcId _id = 0;
+	mutable QReadWriteLock _mutex;
+
 	AuthKeyPtr _key;
 	bool _connectionInited = false;
+	std::atomic<bool> _creatingKey = false;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index 9cb1cade2..b9532ec08 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -172,6 +172,9 @@ DcKeyCreator::DcKeyCreator(
 }
 
 DcKeyCreator::~DcKeyCreator() {
+	if (_delegate.done) {
+		stopReceiving();
+	}
 	const auto clearBytes = [](bytes::span bytes) {
 		OPENSSL_cleanse(bytes.data(), bytes.size());
 	};
@@ -191,11 +194,7 @@ void DcKeyCreator::pqSend() {
 }
 
 void DcKeyCreator::pqAnswered() {
-	QObject::disconnect(
-		_connection,
-		&AbstractConnection::receivedData,
-		nullptr,
-		nullptr);
+	stopReceiving();
 	DEBUG_LOG(("AuthKey Info: receiving Req_pq answer..."));
 
 	MTPReq_pq::ResponseType res_pq;
@@ -272,11 +271,7 @@ void DcKeyCreator::pqAnswered() {
 }
 
 void DcKeyCreator::dhParamsAnswered() {
-	QObject::disconnect(
-		_connection,
-		&AbstractConnection::receivedData,
-		nullptr,
-		nullptr);
+	stopReceiving();
 	DEBUG_LOG(("AuthKey Info: receiving Req_DH_params answer..."));
 
 	MTPReq_DH_params::ResponseType res_DH_params;
@@ -450,11 +445,7 @@ void DcKeyCreator::dhClientParamsSend() {
 }
 
 void DcKeyCreator::dhClientParamsAnswered() {
-	QObject::disconnect(
-		_connection,
-		&AbstractConnection::receivedData,
-		nullptr,
-		nullptr);
+	stopReceiving();
 	DEBUG_LOG(("AuthKey Info: receiving Req_client_DH_params answer..."));
 
 	MTPSet_client_DH_params::ResponseType res_client_DH_params;
@@ -578,7 +569,8 @@ bool DcKeyCreator::readNotSecureResponse(Response &response) {
 }
 
 void DcKeyCreator::failed(Error error) {
-	auto onstack = std::move(_delegate.done);
+	stopReceiving();
+	auto onstack = base::take(_delegate.done);
 	onstack(tl::unexpected(error));
 }
 
@@ -589,8 +581,18 @@ void DcKeyCreator::done(uint64 serverSalt) {
 		_dcId,
 		_authKey);
 	result.serverSalt = serverSalt;
-	auto onstack = std::move(_delegate.done);
+
+	stopReceiving();
+	auto onstack = base::take(_delegate.done);
 	onstack(std::move(result));
 }
 
+void DcKeyCreator::stopReceiving() {
+	QObject::disconnect(
+		_connection,
+		&AbstractConnection::receivedData,
+		nullptr,
+		nullptr);
+}
+
 } // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
index 2dfa2da86..c5738cd48 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -83,6 +83,7 @@ private:
 	void dhClientParamsSend();
 	void dhClientParamsAnswered();
 
+	void stopReceiving();
 	void failed(Error error = Error::Other);
 	void done(uint64 serverSalt);
 
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 769810e00..62cd32a3a 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -645,7 +645,7 @@ not_null<Dcenter*> Instance::Private::addDc(
 	const auto dcId = BareDcId(shiftedDcId);
 	return _dcenters.emplace(
 		shiftedDcId,
-		std::make_unique<Dcenter>(_instance, dcId, std::move(key))
+		std::make_unique<Dcenter>(dcId, std::move(key))
 	).first->second.get();
 }
 
@@ -690,6 +690,10 @@ void Instance::Private::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
 	} else {
 		_keysForWrite.erase(dcId);
 	}
+	crl::on_main(_instance, [=] {
+		DEBUG_LOG(("AuthKey Info: writing auth keys, called by dc %1").arg(dcId));
+		Local::writeMtpData();
+	});
 }
 
 AuthKeysList Instance::Private::getKeysForWrite() const {
@@ -1578,17 +1582,16 @@ void Instance::Private::checkMainDcKey() {
 }
 
 void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
-	if (dcId == _mainDcId) {
-		for (const auto &[id, dc] : _dcenters) {
-			dc->destroyKey();
+	LOG(("Destroying key for dc: %1").arg(dcId));
+	if (const auto dc = findDc(dcId)) {
+		if (dc->destroyConfirmedForgottenKey(keyId)) {
+			LOG(("Key destroyed!"));
+			setKeyForWrite(dcId, nullptr);
+		} else {
+			LOG(("Key already is different."));
 		}
-		restart();
-	} else {
-		if (const auto dc = findDc(dcId)) {
-			return dc->destroyKey();
-		}
-		restart(dcId);
 	}
+	restart(dcId);
 }
 
 void Instance::Private::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
@@ -1737,7 +1740,9 @@ void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
 }
 
 void Instance::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
-	_private->setKeyForWrite(dcId, key);
+	InvokeQueued(this, [=] {
+		_private->setKeyForWrite(dcId, key);
+	});
 }
 
 AuthKeysList Instance::getKeysForWrite() const {
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 2fdbdf23f..04a1afb1c 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -38,14 +38,16 @@ public:
 		QString deviceModel;
 		QString systemVersion;
 	};
+
 	enum class Mode {
 		Normal,
 		KeysDestroyer,
 	};
-	Instance(not_null<DcOptions*> options, Mode mode, Config &&config);
 
+	Instance(not_null<DcOptions*> options, Mode mode, Config &&config);
 	Instance(const Instance &other) = delete;
 	Instance &operator=(const Instance &other) = delete;
+	~Instance();
 
 	void resolveProxyDomain(const QString &host);
 	void setGoodProxyDomain(const QString &host, const QString &ip);
@@ -56,16 +58,71 @@ public:
 	[[nodiscard]] QString cloudLangCode() const;
 	[[nodiscard]] QString langPackName() const;
 
-	// Thread safe.
+	// Thread-safe.
 	[[nodiscard]] QString deviceModel() const;
 	[[nodiscard]] QString systemVersion() const;
-
 	void setKeyForWrite(DcId dcId, const AuthKeyPtr &key);
+
+	// Main thread.
 	[[nodiscard]] AuthKeysList getKeysForWrite() const;
 	void addKeysForDestroy(AuthKeysList &&keys);
 
 	[[nodiscard]] not_null<DcOptions*> dcOptions();
 
+	void restart();
+	void restart(ShiftedDcId shiftedDcId);
+	int32 dcstate(ShiftedDcId shiftedDcId = 0);
+	QString dctransport(ShiftedDcId shiftedDcId = 0);
+	void ping();
+	void cancel(mtpRequestId requestId);
+	int32 state(mtpRequestId requestId); // < 0 means waiting for such count of ms
+
+	// Main thread.
+	void killSession(ShiftedDcId shiftedDcId);
+	void stopSession(ShiftedDcId shiftedDcId);
+	void reInitConnection(DcId dcId);
+	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
+
+	void unpaused();
+
+	void queueQuittingConnection(std::unique_ptr<internal::Connection> &&connection);
+
+	void setUpdatesHandler(RPCDoneHandlerPtr onDone);
+	void setGlobalFailHandler(RPCFailHandlerPtr onFail);
+	void setStateChangedHandler(Fn<void(ShiftedDcId shiftedDcId, int32 state)> handler);
+	void setSessionResetHandler(Fn<void(ShiftedDcId shiftedDcId)> handler);
+	void clearGlobalHandlers();
+
+	void onStateChange(ShiftedDcId shiftedDcId, int32 state);
+	void onSessionReset(ShiftedDcId shiftedDcId);
+
+	void clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids);
+
+	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
+	bool hasCallbacks(mtpRequestId requestId);
+	void globalCallback(const mtpPrime *from, const mtpPrime *end);
+
+	// return true if need to clean request data
+	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
+
+	bool isKeysDestroyer() const;
+	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
+	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
+	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
+
+	void requestConfig();
+	void requestConfigIfOld();
+	void requestCDNConfig();
+	void setUserPhone(const QString &phone);
+	void badConfigurationError();
+
+	void syncHttpUnixtime();
+
+	void connectionFinished(not_null<internal::Connection*> connection);
+
+	void sendAnything(ShiftedDcId shiftedDcId = 0, crl::time msCanWait = 0);
+	void sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key);
+
 	template <typename Request>
 	mtpRequestId send(
 			const Request &request,
@@ -134,60 +191,6 @@ public:
 			afterRequestId);
 	}
 
-	void sendAnything(ShiftedDcId shiftedDcId = 0, crl::time msCanWait = 0);
-	void sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key);
-
-	void restart();
-	void restart(ShiftedDcId shiftedDcId);
-	int32 dcstate(ShiftedDcId shiftedDcId = 0);
-	QString dctransport(ShiftedDcId shiftedDcId = 0);
-	void ping();
-	void cancel(mtpRequestId requestId);
-	int32 state(mtpRequestId requestId); // < 0 means waiting for such count of ms
-	void killSession(ShiftedDcId shiftedDcId);
-	void stopSession(ShiftedDcId shiftedDcId);
-	void reInitConnection(DcId dcId);
-	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
-
-	void unpaused();
-
-	void queueQuittingConnection(std::unique_ptr<internal::Connection> &&connection);
-
-	void setUpdatesHandler(RPCDoneHandlerPtr onDone);
-	void setGlobalFailHandler(RPCFailHandlerPtr onFail);
-	void setStateChangedHandler(Fn<void(ShiftedDcId shiftedDcId, int32 state)> handler);
-	void setSessionResetHandler(Fn<void(ShiftedDcId shiftedDcId)> handler);
-	void clearGlobalHandlers();
-
-	void onStateChange(ShiftedDcId shiftedDcId, int32 state);
-	void onSessionReset(ShiftedDcId shiftedDcId);
-
-	void clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids);
-
-	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
-	bool hasCallbacks(mtpRequestId requestId);
-	void globalCallback(const mtpPrime *from, const mtpPrime *end);
-
-	// return true if need to clean request data
-	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
-
-	bool isKeysDestroyer() const;
-	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
-	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
-	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
-
-	void requestConfig();
-	void requestConfigIfOld();
-	void requestCDNConfig();
-	void setUserPhone(const QString &phone);
-	void badConfigurationError();
-
-	void syncHttpUnixtime();
-
-	void connectionFinished(not_null<internal::Connection*> connection);
-
-	~Instance();
-
 signals:
 	void configLoaded();
 	void cdnConfigLoaded();
diff --git a/Telegram/SourceFiles/mtproto/rpc_sender.h b/Telegram/SourceFiles/mtproto/rpc_sender.h
index 068bd4d32..4de116548 100644
--- a/Telegram/SourceFiles/mtproto/rpc_sender.h
+++ b/Telegram/SourceFiles/mtproto/rpc_sender.h
@@ -261,13 +261,13 @@ private:
 };
 
 struct RPCCallbackClear {
-	RPCCallbackClear(mtpRequestId id , int32 code = RPCError::NoError)
+	RPCCallbackClear(mtpRequestId id, int32 code = RPCError::NoError)
 	: requestId(id)
 	, errorCode(code) {
 	}
 
-	mtpRequestId requestId;
-	int32 errorCode;
+	mtpRequestId requestId = 0;
+	int32 errorCode = 0;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 709ebf1ff..3d525cf7c 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/dcenter.h"
 #include "mtproto/auth_key.h"
 #include "base/unixtime.h"
+#include "base/openssl_help.h"
 #include "core/crash_reports.h"
 #include "facades.h"
 
@@ -63,19 +64,15 @@ ConnectionOptions::ConnectionOptions(
 , useTcp(useTcp) {
 }
 
-void SessionData::setKey(const AuthKeyPtr &key) {
-	if (_authKey != key) {
-		const auto sessionId = rand_value<uint64>();
-		_authKey = key;
-
-		DEBUG_LOG(("MTP Info: new auth key set in SessionData, id %1, setting random server_session %2").arg(key ? key->keyId() : 0).arg(sessionId));
-		QWriteLocker locker(&_lock);
-		if (_sessionId != sessionId) {
-			_sessionId = sessionId;
-			_messagesSent = 0;
-		}
-		_layerInited = false;
+void SessionData::setCurrentKeyId(uint64 keyId) {
+	QWriteLocker locker(&_lock);
+	if (_keyId == keyId) {
+		return;
 	}
+	_keyId = keyId;
+	_sessionId = openssl::RandomValue<uint64>();
+	_messagesSent = 0;
+	DEBUG_LOG(("MTP Info: new auth key set in SessionData, id %1, setting random server_session %2").arg(_keyId).arg(_sessionId));
 }
 
 void SessionData::setKeyForCheck(const AuthKeyPtr &key) {
@@ -83,25 +80,24 @@ void SessionData::setKeyForCheck(const AuthKeyPtr &key) {
 }
 
 void SessionData::notifyConnectionInited(const ConnectionOptions &options) {
-	QWriteLocker locker(&_lock);
-	if (options.cloudLangCode == _options.cloudLangCode
-		&& options.systemLangCode == _options.systemLangCode
-		&& options.langPackName == _options.langPackName
-		&& options.proxy == _options.proxy
-		&& !_options.inited) {
-		_options.inited = true;
-
-		locker.unlock();
+	// #TODO race
+	const auto current = connectionOptions();
+	if (current.cloudLangCode == _options.cloudLangCode
+		&& current.systemLangCode == _options.systemLangCode
+		&& current.langPackName == _options.langPackName
+		&& current.proxy == _options.proxy) {
 		owner()->notifyDcConnectionInited();
 	}
 }
 
-void SessionData::clear(Instance *instance) {
+void SessionData::clearForNewKey(not_null<Instance*> instance) {
 	auto clearCallbacks = std::vector<RPCCallbackClear>();
 	{
-		QReadLocker locker1(haveSentMutex()), locker2(toResendMutex()), locker3(haveReceivedMutex()), locker4(wereAckedMutex());
-		auto receivedResponsesEnd = _receivedResponses.cend();
-		clearCallbacks.reserve(_haveSent.size() + _wereAcked.size());
+		QReadLocker locker1(haveSentMutex());
+		QReadLocker locker2(toResendMutex());
+		QReadLocker locker3(haveReceivedMutex());
+		QReadLocker locker4(wereAckedMutex());
+		clearCallbacks.reserve(_haveSent.size() + _toResend.size() + _wereAcked.size());
 		for (auto i = _haveSent.cbegin(), e = _haveSent.cend(); i != e; ++i) {
 			auto requestId = i.value()->requestId;
 			if (!_receivedResponses.contains(requestId)) {
@@ -147,21 +143,15 @@ Session::Session(
 : QObject()
 , _instance(instance)
 , _shiftedDcId(shiftedDcId)
-, _dc(dc)
+, _ownedDc(dc ? nullptr : std::make_unique<Dcenter>(shiftedDcId, nullptr))
+, _dc(dc ? dc : _ownedDc.get())
 , _data(this)
 , _timeouter([=] { checkRequestsByTimer(); })
 , _sender([=] { needToResumeAndSend(); }) {
 	_timeouter.callEach(1000);
 	refreshOptions();
-	if (_dc) {
-		if (const auto lock = ReadLockerAttempt(keyMutex())) {
-			_data.setKey(_dc->getKey());
-			if (_dc->connectionInited()) {
-				_data.setConnectionInited();
-			}
-		}
-		connect(_dc, SIGNAL(authKeyCreated()), this, SLOT(authKeyCreatedForDC()), Qt::QueuedConnection);
-		connect(_dc, SIGNAL(connectionWasInited()), this, SLOT(connectionWasInitedForDC()), Qt::QueuedConnection);
+	if (sharedDc()) {
+		connect(_dc, SIGNAL(authKeyChanged()), this, SLOT(authKeyChangedForDC()), Qt::QueuedConnection);
 	}
 }
 
@@ -199,7 +189,7 @@ void Session::refreshOptions() {
 	const auto useHttp = (proxyType != ProxyData::Type::Mtproto);
 	const auto useIPv4 = true;
 	const auto useIPv6 = Global::TryIPv6();
-	_data.applyConnectionOptions(ConnectionOptions(
+	_data.setConnectionOptions(ConnectionOptions(
 		_instance->systemLangCode(),
 		_instance->cloudLangCode(),
 		_instance->langPackName(),
@@ -213,10 +203,7 @@ void Session::refreshOptions() {
 }
 
 void Session::reInitConnection() {
-	if (_dc) {
-		_dc->setConnectionInited(false);
-	}
-	_data.setConnectionInited(false);
+	_dc->setConnectionInited(false);
 	restart();
 }
 
@@ -315,6 +302,10 @@ void Session::sendMsgsStateInfo(quint64 msgId, QByteArray data) {
 			MTP_msgs_state_info(MTP_long(msgId), MTP_bytes(data))));
 }
 
+bool Session::sharedDc() const {
+	return (_ownedDc == nullptr);
+}
+
 void Session::checkRequestsByTimer() {
 	QVector<mtpMsgId> resendingIds;
 	QVector<mtpMsgId> removingIds; // remove very old (10 minutes) containers and resend requests
@@ -555,51 +546,44 @@ void Session::sendPrepared(
 	sendAnything(msCanWait);
 }
 
-QReadWriteLock *Session::keyMutex() const {
-	return _dc ? _dc->keyMutex() : nullptr;
+void Session::authKeyChangedForDC() {
+	DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, emitting authKeyChanged(), dcWithShift %1").arg(_shiftedDcId));
+	emit authKeyChanged();
 }
 
-void Session::authKeyCreatedForDC() {
-	Expects(_dc != nullptr);
-
-	DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, emitting authKeyCreated(), dcWithShift %1").arg(_shiftedDcId));
-	_data.setKey(_dc->getKey());
-	emit authKeyCreated();
+bool Session::acquireKeyCreation() {
+	return _dc->acquireKeyCreation();
 }
 
-void Session::notifyKeyCreated(AuthKeyPtr &&key) {
-	DEBUG_LOG(("AuthKey Info: Session::keyCreated(), setting, dcWithShift %1").arg(_shiftedDcId));
-	if (_dc) {
-		_dc->setKey(std::move(key));
-	} else {
-		_data.setKey(std::move(key));
-		emit authKeyCreated();
+void Session::releaseKeyCreationOnFail() {
+	_dc->releaseKeyCreationOnFail();
+}
+
+void Session::releaseKeyCreationOnDone(AuthKeyPtr &&key) {
+	DEBUG_LOG(("AuthKey Info: Session key created, setting, dcWithShift %1").arg(_shiftedDcId));
+	if (sharedDc()) {
+		const auto dcId = _dc->id();
+		const auto instance = _instance;
+		InvokeQueued(instance, [=] {
+			instance->setKeyForWrite(dcId, key);
+		});
 	}
-}
-
-void Session::connectionWasInitedForDC() {
-	Expects(_dc != nullptr);
-
-	DEBUG_LOG(("MTP Info: Session::connectionWasInitedForDC slot, dcWithShift %1").arg(_shiftedDcId));
-	_data.setConnectionInited();
+	_dc->releaseKeyCreationOnDone(std::move(key));
 }
 
 void Session::notifyDcConnectionInited() {
 	DEBUG_LOG(("MTP Info: emitting MTProtoDC::connectionWasInited(), dcWithShift %1").arg(_shiftedDcId));
-	if (_dc) {
-		_dc->setConnectionInited();
-	} else {
-		_data.setConnectionInited();
-	}
+	_dc->setConnectionInited();
 }
 
-void Session::destroyKey() {
-	if (const auto key = _data.getKey()) {
-		DEBUG_LOG(("MTP Info: destroying auth_key for dcWithShift %1").arg(_shiftedDcId));
-		if (_dc && _dc->getKey() == key) {
-			_dc->destroyKey();
-		}
-		_data.setKey(nullptr);
+void Session::destroyCdnKey(uint64 keyId) {
+	_dc->destroyCdnKey(keyId);
+	if (sharedDc()) {
+		const auto dcId = _dc->id();
+		const auto instance = _instance;
+		InvokeQueued(instance, [=] {
+			instance->setKeyForWrite(dcId, nullptr);
+		});
 	}
 }
 
@@ -607,6 +591,14 @@ int32 Session::getDcWithShift() const {
 	return _shiftedDcId;
 }
 
+AuthKeyPtr Session::getKey() const {
+	return _dc->getKey();
+}
+
+bool Session::connectionInited() const {
+	return _dc->connectionInited();
+}
+
 void Session::tryToReceive() {
 	if (_killed) {
 		DEBUG_LOG(("Session Error: can't receive in a killed session"));
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 536998bd8..1d6ffb68c 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -131,7 +131,6 @@ struct ConnectionOptions {
 	bool useIPv6 = true;
 	bool useHttp = true;
 	bool useTcp = true;
-	bool inited = false;
 
 };
 
@@ -141,6 +140,7 @@ public:
 	SessionData(not_null<Session*> creator) : _owner(creator) {
 	}
 
+	void setCurrentKeyId(uint64 keyId);
 	void setSessionId(uint64 sessionId) {
 		DEBUG_LOG(("MTP Info: setting server_session: %1").arg(sessionId));
 
@@ -150,22 +150,16 @@ public:
 			_messagesSent = 0;
 		}
 	}
-	uint64 getSessionId() const {
+	[[nodiscard]] uint64 getSessionId() const {
 		QReadLocker locker(&_lock);
 		return _sessionId;
 	}
-	void setConnectionInited(bool inited = true) {
-		QWriteLocker locker(&_lock);
-		_options.inited = inited;
-	}
 	void notifyConnectionInited(const ConnectionOptions &options);
-	void applyConnectionOptions(ConnectionOptions options) {
+	void setConnectionOptions(ConnectionOptions options) {
 		QWriteLocker locker(&_lock);
-		const auto inited = _options.inited;
 		_options = options;
-		_options.inited = inited;
 	}
-	ConnectionOptions connectionOptions() const {
+	[[nodiscard]] ConnectionOptions connectionOptions() const {
 		QReadLocker locker(&_lock);
 		return _options;
 	}
@@ -174,23 +168,16 @@ public:
 		QWriteLocker locker(&_lock);
 		_salt = salt;
 	}
-	uint64 getSalt() const {
+	[[nodiscard]] uint64 getSalt() const {
 		QReadLocker locker(&_lock);
 		return _salt;
 	}
 
-	const AuthKeyPtr &getKey() const {
-		return _authKey;
-	}
-	void setKey(const AuthKeyPtr &key);
-
-	const AuthKeyPtr &getKeyForCheck() const {
+	[[nodiscard]] const AuthKeyPtr &getKeyForCheck() const {
 		return _dcKeyForCheck;
 	}
 	void setKeyForCheck(const AuthKeyPtr &key);
 
-	QReadWriteLock *keyMutex() const;
-
 	not_null<QReadWriteLock*> toSendMutex() const {
 		return &_toSendLock;
 	}
@@ -276,19 +263,17 @@ public:
 		return result * 2 + (needAck ? 1 : 0);
 	}
 
-	void clear(Instance *instance);
+	void clearForNewKey(not_null<Instance*> instance);
 
 private:
+	uint64 _keyId = 0;
 	uint64 _sessionId = 0;
 	uint64 _salt = 0;
-
 	uint32 _messagesSent = 0;
 
 	not_null<Session*> _owner;
 
-	AuthKeyPtr _authKey;
 	AuthKeyPtr _dcKeyForCheck;
-	bool _layerInited = false;
 	ConnectionOptions _options;
 
 	PreRequestMap _toSend; // map of request_id -> request, that is waiting to be sent
@@ -317,25 +302,34 @@ class Session : public QObject {
 	Q_OBJECT
 
 public:
+	// Main thread.
 	Session(
 		not_null<Instance*> instance,
 		ShiftedDcId shiftedDcId,
 		Dcenter *dc);
+	~Session();
 
 	void start();
+	void reInitConnection();
+
 	void restart();
 	void refreshOptions();
-	void reInitConnection();
 	void stop();
 	void kill();
 
 	void unpaused();
 
-	ShiftedDcId getDcWithShift() const;
+	// Thread-safe.
+	[[nodiscard]] ShiftedDcId getDcWithShift() const;
+	[[nodiscard]] AuthKeyPtr getKey() const;
+	[[nodiscard]] bool connectionInited() const;
+
+	// Connection thread.
+	[[nodiscard]] bool acquireKeyCreation();
+	void releaseKeyCreationOnFail();
+	void releaseKeyCreationOnDone(AuthKeyPtr &&key);
+	void destroyCdnKey(uint64 keyId);
 
-	QReadWriteLock *keyMutex() const;
-	void notifyKeyCreated(AuthKeyPtr &&key);
-	void destroyKey();
 	void notifyDcConnectionInited();
 
 	void ping();
@@ -352,10 +346,8 @@ public:
 		crl::time msCanWait = 0,
 		bool newRequest = true);
 
-	~Session();
-
 signals:
-	void authKeyCreated();
+	void authKeyChanged();
 	void needToSend();
 	void needToPing();
 	void needToRestart();
@@ -367,8 +359,7 @@ public slots:
 	void resendMany(QVector<quint64> msgIds, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo);
 	void resendAll(); // after connection restart
 
-	void authKeyCreatedForDC();
-	void connectionWasInitedForDC();
+	void authKeyChangedForDC();
 
 	void tryToReceive();
 	void onConnectionStateChange(qint32 newState);
@@ -379,13 +370,15 @@ public slots:
 	void sendMsgsStateInfo(quint64 msgId, QByteArray data);
 
 private:
+	[[nodiscard]] bool sharedDc() const;
 	void checkRequestsByTimer();
 
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
 
 	const not_null<Instance*> _instance;
 	const ShiftedDcId _shiftedDcId = 0;
-	Dcenter *_dc = nullptr;
+	const std::unique_ptr<Dcenter> _ownedDc;
+	const not_null<Dcenter*> _dc;
 
 	std::unique_ptr<Connection> _connection;
 
@@ -406,38 +399,5 @@ private:
 
 };
 
-inline QReadWriteLock *SessionData::keyMutex() const {
-	return _owner->keyMutex();
-}
-
-class ReadLockerAttempt {
-public:
-	ReadLockerAttempt(QReadWriteLock *lock) : _lock(lock), _locked(_lock ? _lock->tryLockForRead() : true) {
-	}
-	ReadLockerAttempt(const ReadLockerAttempt &other) = delete;
-	ReadLockerAttempt &operator=(const ReadLockerAttempt &other) = delete;
-	ReadLockerAttempt(ReadLockerAttempt &&other) : _lock(other._lock), _locked(base::take(other._locked)) {
-	}
-	ReadLockerAttempt &operator=(ReadLockerAttempt &&other) {
-		_lock = other._lock;
-		_locked = base::take(other._locked);
-		return *this;
-	}
-	~ReadLockerAttempt() {
-		if (_lock && _locked) {
-			_lock->unlock();
-		}
-	}
-
-	operator bool() const {
-		return _locked;
-	}
-
-private:
-	QReadWriteLock *_lock = nullptr;
-	bool _locked = false;
-
-};
-
 } // namespace internal
 } // namespace MTP

From 1ef877d9a5dd8ca6c1c0d737184331f5fd15e9df Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Wed, 6 Nov 2019 23:11:56 +0300
Subject: [PATCH 18/91] Fixed moving cursor to begin/end when using reply
 shortcuts for macOS.

---
 Telegram/SourceFiles/history/history_widget.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Telegram/SourceFiles/history/history_widget.cpp b/Telegram/SourceFiles/history/history_widget.cpp
index 069b81a11..3ff0e1619 100644
--- a/Telegram/SourceFiles/history/history_widget.cpp
+++ b/Telegram/SourceFiles/history/history_widget.cpp
@@ -3610,8 +3610,20 @@ bool HistoryWidget::eventFilter(QObject *obj, QEvent *e) {
 		const auto k = static_cast<QKeyEvent*>(e);
 		if ((k->modifiers() & kCommonModifiers) == Qt::ControlModifier) {
 			if (k->key() == Qt::Key_Up) {
+#ifdef Q_OS_MAC
+				// Cmd + Up is used instead of Home.
+				if (!_field->textCursor().atStart()) {
+					return false;
+				}
+#endif
 				return replyToPreviousMessage();
 			} else if (k->key() == Qt::Key_Down) {
+#ifdef Q_OS_MAC
+				// Cmd + Down is used instead of End.
+				if (!_field->textCursor().atEnd()) {
+					return false;
+				}
+#endif
 				return replyToNextMessage();
 			}
 		}

From cfcd12e8799a52f4c341a5e18a5275dcf1099ccb Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 15 Nov 2019 16:10:41 +0300
Subject: [PATCH 19/91] Several spellchecker fixes.

---
 Telegram/lib_spellcheck | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/lib_spellcheck b/Telegram/lib_spellcheck
index 0269666de..6dcaae361 160000
--- a/Telegram/lib_spellcheck
+++ b/Telegram/lib_spellcheck
@@ -1 +1 @@
-Subproject commit 0269666dea57837f56f0eca965fc1f1a61bb9e27
+Subproject commit 6dcaae361d942defb5908400bb3f4bf805a5e740

From 8fa9172818bb4ee0430b0751522c3b85d5ece7de Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 15 Nov 2019 16:11:17 +0300
Subject: [PATCH 20/91] Closed alpha version 1.9.1.1.

---
 Telegram/Resources/uwp/AppX/AppxManifest.xml | 2 +-
 Telegram/Resources/winrc/Telegram.rc         | 8 ++++----
 Telegram/Resources/winrc/Updater.rc          | 8 ++++----
 Telegram/SourceFiles/core/version.h          | 4 ++--
 Telegram/build/version                       | 4 ++--
 5 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Telegram/Resources/uwp/AppX/AppxManifest.xml b/Telegram/Resources/uwp/AppX/AppxManifest.xml
index 91eed0956..3f378237a 100644
--- a/Telegram/Resources/uwp/AppX/AppxManifest.xml
+++ b/Telegram/Resources/uwp/AppX/AppxManifest.xml
@@ -9,7 +9,7 @@
   <Identity Name="TelegramMessengerLLP.TelegramDesktop"
     ProcessorArchitecture="ARCHITECTURE"
     Publisher="CN=536BC709-8EE1-4478-AF22-F0F0F26FF64A"
-    Version="1.9.1.0" />
+    Version="1.9.1.1" />
   <Properties>
     <DisplayName>Telegram Desktop</DisplayName>
     <PublisherDisplayName>Telegram FZ-LLC</PublisherDisplayName>
diff --git a/Telegram/Resources/winrc/Telegram.rc b/Telegram/Resources/winrc/Telegram.rc
index 4ace1984c..f4e3a8506 100644
--- a/Telegram/Resources/winrc/Telegram.rc
+++ b/Telegram/Resources/winrc/Telegram.rc
@@ -33,8 +33,8 @@ IDI_ICON1               ICON                    "..\\art\\icon256.ico"
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,0
- PRODUCTVERSION 1,9,1,0
+ FILEVERSION 1,9,1,1
+ PRODUCTVERSION 1,9,1,1
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -51,10 +51,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop"
-            VALUE "FileVersion", "1.9.1.0"
+            VALUE "FileVersion", "1.9.1.1"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.0"
+            VALUE "ProductVersion", "1.9.1.1"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/Resources/winrc/Updater.rc b/Telegram/Resources/winrc/Updater.rc
index 29dcc0b7b..74f56f7ee 100644
--- a/Telegram/Resources/winrc/Updater.rc
+++ b/Telegram/Resources/winrc/Updater.rc
@@ -24,8 +24,8 @@ LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,0
- PRODUCTVERSION 1,9,1,0
+ FILEVERSION 1,9,1,1
+ PRODUCTVERSION 1,9,1,1
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -42,10 +42,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop Updater"
-            VALUE "FileVersion", "1.9.1.0"
+            VALUE "FileVersion", "1.9.1.1"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.0"
+            VALUE "ProductVersion", "1.9.1.1"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/SourceFiles/core/version.h b/Telegram/SourceFiles/core/version.h
index 111d359d5..84ba377de 100644
--- a/Telegram/SourceFiles/core/version.h
+++ b/Telegram/SourceFiles/core/version.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#define TDESKTOP_REQUESTED_ALPHA_VERSION (0ULL)
+#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001001ULL)
 
 #ifdef TDESKTOP_OFFICIAL_TARGET
 #define TDESKTOP_ALPHA_VERSION TDESKTOP_REQUESTED_ALPHA_VERSION
@@ -17,5 +17,5 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 constexpr auto AppVersion = 1009001;
 constexpr auto AppVersionStr = "1.9.1";
-constexpr auto AppBetaVersion = true;
+constexpr auto AppBetaVersion = false;
 constexpr auto AppAlphaVersion = TDESKTOP_ALPHA_VERSION;
diff --git a/Telegram/build/version b/Telegram/build/version
index d4f9f3413..c77479b5c 100644
--- a/Telegram/build/version
+++ b/Telegram/build/version
@@ -2,5 +2,5 @@ AppVersion         1009001
 AppVersionStrMajor 1.9
 AppVersionStrSmall 1.9.1
 AppVersionStr      1.9.1
-BetaChannel        1
-AlphaVersion       0
+BetaChannel        0
+AlphaVersion       1009001001

From 90c6475c8c7f242d32224c24178a9a50eaa2c9fc Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 15 Nov 2019 17:11:05 +0300
Subject: [PATCH 21/91] Closed alpha version 1.9.1.1: Fix build on macOS.

---
 Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index b9532ec08..7b1ca17f0 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -14,6 +14,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "scheme.h"
 #include "logs.h"
 
+#include <cmath>
+
 namespace MTP::details {
 namespace {
 

From c961acabbc505ee6220270748f126d5ab27e7ecd Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 10:52:08 +0300
Subject: [PATCH 22/91] Include private header only if needed.

---
 Telegram/SourceFiles/platform/linux/file_utilities_linux.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Telegram/SourceFiles/platform/linux/file_utilities_linux.cpp b/Telegram/SourceFiles/platform/linux/file_utilities_linux.cpp
index 823cccaaf..5bb691f23 100644
--- a/Telegram/SourceFiles/platform/linux/file_utilities_linux.cpp
+++ b/Telegram/SourceFiles/platform/linux/file_utilities_linux.cpp
@@ -18,7 +18,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "facades.h"
 
 #include <QtCore/QProcess>
+
+#ifndef TDESKTOP_DISABLE_GTK_INTEGRATION
 #include <private/qguiapplication_p.h>
+#endif // TDESKTOP_DISABLE_GTK_INTEGRATION
 
 QStringList qt_make_filter_list(const QString &filter);
 

From da4120bdddbc18be780a4ff6f353893d68635f27 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 10:52:32 +0300
Subject: [PATCH 23/91] Fix building without glib.

---
 .../SourceFiles/platform/linux/notifications_manager_linux.cpp  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp b/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp
index cfba893de..b2dd4e2f6 100644
--- a/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp
+++ b/Telegram/SourceFiles/platform/linux/notifications_manager_linux.cpp
@@ -366,7 +366,7 @@ void Manager::Private::init(Manager *manager) {
 			auto capabilityText = QString::fromUtf8(static_cast<const char*>(capability->data));
 			_capabilities.push_back(capabilityText);
 		}
-		Libs::g_list_free_full(capabilities, g_free);
+		Libs::g_list_free_full(capabilities, Libs::g_free);
 
 		LOG(("LibNotify capabilities: %1").arg(_capabilities.join(qstr(", "))));
 		if (_capabilities.contains(qsl("actions"))) {

From 1afae74d1eedf0ce0afb85ea7f252f5969592bdf Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 10:52:45 +0300
Subject: [PATCH 24/91] Remove libdee from linking.

---
 Telegram/gyp/telegram/linux.gypi | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Telegram/gyp/telegram/linux.gypi b/Telegram/gyp/telegram/linux.gypi
index ba6bc45e8..5fd7dd057 100644
--- a/Telegram/gyp/telegram/linux.gypi
+++ b/Telegram/gyp/telegram/linux.gypi
@@ -79,7 +79,6 @@
         'cflags_cc': [
           '<!(pkg-config 2> /dev/null --cflags gtk+-2.0)',
           '<!(pkg-config 2> /dev/null --cflags glib-2.0)',
-          '<!(pkg-config 2> /dev/null --cflags dee-1.0)',
         ],
       }], ['<!(pkg-config ayatana-appindicator3-0.1; echo $?) == 0', {
         'cflags_cc': [ '<!(pkg-config --cflags ayatana-appindicator3-0.1)' ],

From 50b2b6c5b1d6ec61b0b2a8c4fd46b9f4513eb227 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 11:46:53 +0300
Subject: [PATCH 25/91] Use installed opus on non-Windows.

---
 .travis/build.sh              | 1 -
 Telegram/ThirdParty/libtgvoip | 2 +-
 Telegram/gyp/helpers          | 2 +-
 3 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/.travis/build.sh b/.travis/build.sh
index 1a1f55d78..6033b51d3 100755
--- a/.travis/build.sh
+++ b/.travis/build.sh
@@ -694,7 +694,6 @@ buildTelegram() {
       -Dlinux_path_qt=$QT_PATH \
       -Dlinux_path_breakpad=$BREAKPAD_PATH \
       -Dlinux_path_libexif_lib=/usr/local/lib \
-      -Dlinux_path_opus_include=/usr/include/opus \
       -Dlinux_lib_ssl=-lssl \
       -Dlinux_lib_crypto=-lcrypto \
       -Dlinux_lib_icu=-licuuc\ -licutu\ -licui18n \
diff --git a/Telegram/ThirdParty/libtgvoip b/Telegram/ThirdParty/libtgvoip
index 302d42fc2..75b4565a5 160000
--- a/Telegram/ThirdParty/libtgvoip
+++ b/Telegram/ThirdParty/libtgvoip
@@ -1 +1 @@
-Subproject commit 302d42fc201f9a8b973ba152e04cf804b0d9d521
+Subproject commit 75b4565a5bab8fb24afe315aeda2131c7a1f362a
diff --git a/Telegram/gyp/helpers b/Telegram/gyp/helpers
index 1b346350e..9d456ff5e 160000
--- a/Telegram/gyp/helpers
+++ b/Telegram/gyp/helpers
@@ -1 +1 @@
-Subproject commit 1b346350ead307c8d7015a9b4fd6a8af06e0efd2
+Subproject commit 9d456ff5e1dafc7f3bc3f788707806a6001435ab

From a05e2f0d8d72b0ea747d0508ec19bf2f45fdc7fc Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 12:10:31 +0300
Subject: [PATCH 26/91] Use 'uname -m' instead of 'uname -p'.

---
 Telegram/gyp/helpers             | 2 +-
 Telegram/gyp/telegram/linux.gypi | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Telegram/gyp/helpers b/Telegram/gyp/helpers
index 9d456ff5e..5b000acfb 160000
--- a/Telegram/gyp/helpers
+++ b/Telegram/gyp/helpers
@@ -1 +1 @@
-Subproject commit 9d456ff5e1dafc7f3bc3f788707806a6001435ab
+Subproject commit 5b000acfb554e98b6575203cd84859bc4cc9d344
diff --git a/Telegram/gyp/telegram/linux.gypi b/Telegram/gyp/telegram/linux.gypi
index 5fd7dd057..521dd8f40 100644
--- a/Telegram/gyp/telegram/linux.gypi
+++ b/Telegram/gyp/telegram/linux.gypi
@@ -71,7 +71,7 @@
       },
     },
     'conditions': [
-      [ '"<!(uname -p)" != "x86_64"', {
+      [ '"<!(uname -m)" != "x86_64"', {
         'ldflags': [
           '-Wl,-wrap,__divmoddi4',
         ],

From 782025a0a6717cddcddc3369f1141054c35a4c46 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 12:10:52 +0300
Subject: [PATCH 27/91] Wrap 'divmodti4' the same as 'divmoddi4'.

---
 Telegram/gyp/telegram/linux.gypi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Telegram/gyp/telegram/linux.gypi b/Telegram/gyp/telegram/linux.gypi
index 521dd8f40..59f6acc93 100644
--- a/Telegram/gyp/telegram/linux.gypi
+++ b/Telegram/gyp/telegram/linux.gypi
@@ -75,6 +75,10 @@
         'ldflags': [
           '-Wl,-wrap,__divmoddi4',
         ],
+      }, {
+        'ldflags': [
+          '-Wl,-wrap,__divmodti4',
+        ],
       }], ['not_need_gtk!="True"', {
         'cflags_cc': [
           '<!(pkg-config 2> /dev/null --cflags gtk+-2.0)',

From cfe12f773fa6b5a6618516e95a9b147c40e68eca Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 12:28:14 +0300
Subject: [PATCH 28/91] Move some modules to lib_mtproto.

---
 Telegram/SourceFiles/boxes/calendar_box.cpp   |  2 +-
 Telegram/SourceFiles/boxes/confirm_box.h      |  2 +-
 .../SourceFiles/boxes/confirm_phone_box.h     |  2 +-
 Telegram/SourceFiles/boxes/edit_caption_box.h |  2 +-
 Telegram/SourceFiles/boxes/report_box.h       |  2 +-
 Telegram/SourceFiles/boxes/share_box.h        |  2 +-
 Telegram/SourceFiles/boxes/username_box.h     |  2 +-
 Telegram/SourceFiles/calls/calls_call.h       |  2 +-
 Telegram/SourceFiles/core/application.h       |  2 +-
 Telegram/SourceFiles/core/utils.cpp           | 14 ---
 Telegram/SourceFiles/core/utils.h             |  4 -
 .../dialogs/dialogs_inner_widget.h            |  2 +-
 Telegram/SourceFiles/dialogs/dialogs_widget.h |  2 +-
 .../SourceFiles/export/export_api_wrap.cpp    |  2 +-
 .../SourceFiles/export/export_controller.h    |  5 +-
 Telegram/SourceFiles/main/main_account.h      |  2 +-
 Telegram/SourceFiles/mainwidget.h             |  2 +-
 .../SourceFiles/mtproto/concurrent_sender.cpp |  4 +-
 Telegram/SourceFiles/mtproto/config_loader.h  |  2 +-
 Telegram/SourceFiles/mtproto/connection.cpp   |  4 +-
 Telegram/SourceFiles/mtproto/connection.h     |  2 +-
 .../mtproto/connection_resolving.h            |  2 +-
 .../SourceFiles/mtproto/connection_tcp.cpp    |  2 +-
 Telegram/SourceFiles/mtproto/connection_tcp.h |  2 +-
 Telegram/SourceFiles/mtproto/dc_options.h     |  2 +-
 Telegram/SourceFiles/mtproto/dcenter.cpp      |  2 +-
 .../mtproto/details/mtproto_dc_key_checker.h  |  2 +-
 .../mtproto/details/mtproto_dc_key_creator.h  |  2 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 16 +++-
 Telegram/SourceFiles/mtproto/mtp_instance.h   | 12 ++-
 ...socket.cpp => mtproto_abstract_socket.cpp} |  6 +-
 ...act_socket.h => mtproto_abstract_socket.h} |  0
 .../{auth_key.cpp => mtproto_auth_key.cpp}    | 95 ++++++++++---------
 .../{auth_key.h => mtproto_auth_key.h}        |  0
 .../mtproto/{mtp_pch.cpp => mtproto_pch.cpp}  |  2 +-
 .../mtproto/{mtp_pch.h => mtproto_pch.h}      |  0
 ...{rpc_sender.cpp => mtproto_rpc_sender.cpp} | 13 ++-
 .../{rpc_sender.h => mtproto_rpc_sender.h}    |  2 -
 ...lic_key.cpp => mtproto_rsa_public_key.cpp} | 14 +--
 ..._public_key.h => mtproto_rsa_public_key.h} |  0
 ..._tcp_socket.cpp => mtproto_tcp_socket.cpp} |  2 +-
 ...{mtp_tcp_socket.h => mtproto_tcp_socket.h} |  2 +-
 ..._tls_socket.cpp => mtproto_tls_socket.cpp} |  4 +-
 ...{mtp_tls_socket.h => mtproto_tls_socket.h} |  2 +-
 Telegram/SourceFiles/mtproto/sender.h         |  2 +-
 Telegram/SourceFiles/mtproto/session.cpp      |  2 +-
 Telegram/SourceFiles/mtproto/session.h        |  2 +-
 .../mtproto/special_config_request.cpp        |  4 +-
 .../passport/passport_encryption.cpp          |  2 +-
 .../SourceFiles/storage/serialize_common.h    |  2 +-
 Telegram/gyp/lib_mtproto.gyp                  | 22 +++--
 Telegram/gyp/telegram/sources.txt             |  6 --
 Telegram/lib_base                             |  2 +-
 53 files changed, 143 insertions(+), 148 deletions(-)
 rename Telegram/SourceFiles/mtproto/{mtp_abstract_socket.cpp => mtproto_abstract_socket.cpp} (84%)
 rename Telegram/SourceFiles/mtproto/{mtp_abstract_socket.h => mtproto_abstract_socket.h} (100%)
 rename Telegram/SourceFiles/mtproto/{auth_key.cpp => mtproto_auth_key.cpp} (64%)
 rename Telegram/SourceFiles/mtproto/{auth_key.h => mtproto_auth_key.h} (100%)
 rename Telegram/SourceFiles/mtproto/{mtp_pch.cpp => mtproto_pch.cpp} (89%)
 rename Telegram/SourceFiles/mtproto/{mtp_pch.h => mtproto_pch.h} (100%)
 rename Telegram/SourceFiles/mtproto/{rpc_sender.cpp => mtproto_rpc_sender.cpp} (78%)
 rename Telegram/SourceFiles/mtproto/{rpc_sender.h => mtproto_rpc_sender.h} (99%)
 rename Telegram/SourceFiles/mtproto/{rsa_public_key.cpp => mtproto_rsa_public_key.cpp} (96%)
 rename Telegram/SourceFiles/mtproto/{rsa_public_key.h => mtproto_rsa_public_key.h} (100%)
 rename Telegram/SourceFiles/mtproto/{mtp_tcp_socket.cpp => mtproto_tcp_socket.cpp} (99%)
 rename Telegram/SourceFiles/mtproto/{mtp_tcp_socket.h => mtproto_tcp_socket.h} (95%)
 rename Telegram/SourceFiles/mtproto/{mtp_tls_socket.cpp => mtproto_tls_socket.cpp} (99%)
 rename Telegram/SourceFiles/mtproto/{mtp_tls_socket.h => mtproto_tls_socket.h} (97%)

diff --git a/Telegram/SourceFiles/boxes/calendar_box.cpp b/Telegram/SourceFiles/boxes/calendar_box.cpp
index 54b14b221..48cfdd794 100644
--- a/Telegram/SourceFiles/boxes/calendar_box.cpp
+++ b/Telegram/SourceFiles/boxes/calendar_box.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "boxes/calendar_box.h"
 
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 #include "ui/widgets/buttons.h"
 #include "lang/lang_keys.h"
 #include "ui/effects/ripple_animation.h"
diff --git a/Telegram/SourceFiles/boxes/confirm_box.h b/Telegram/SourceFiles/boxes/confirm_box.h
index cda3e0670..d3c53edda 100644
--- a/Telegram/SourceFiles/boxes/confirm_box.h
+++ b/Telegram/SourceFiles/boxes/confirm_box.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "boxes/abstract_box.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace Main {
 class Session;
diff --git a/Telegram/SourceFiles/boxes/confirm_phone_box.h b/Telegram/SourceFiles/boxes/confirm_phone_box.h
index b474df152..398b8062f 100644
--- a/Telegram/SourceFiles/boxes/confirm_phone_box.h
+++ b/Telegram/SourceFiles/boxes/confirm_phone_box.h
@@ -10,7 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/abstract_box.h"
 #include "base/timer.h"
 #include "ui/widgets/input_fields.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace Ui {
 class InputField;
diff --git a/Telegram/SourceFiles/boxes/edit_caption_box.h b/Telegram/SourceFiles/boxes/edit_caption_box.h
index 59e821954..d5136afb4 100644
--- a/Telegram/SourceFiles/boxes/edit_caption_box.h
+++ b/Telegram/SourceFiles/boxes/edit_caption_box.h
@@ -11,7 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/storage_media_prepare.h"
 #include "ui/wrap/slide_wrap.h"
 #include "media/clip/media_clip_reader.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace ChatHelpers {
 class TabbedPanel;
diff --git a/Telegram/SourceFiles/boxes/report_box.h b/Telegram/SourceFiles/boxes/report_box.h
index 17ed36236..05782b8ce 100644
--- a/Telegram/SourceFiles/boxes/report_box.h
+++ b/Telegram/SourceFiles/boxes/report_box.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "boxes/abstract_box.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace Ui {
 template <typename Enum>
diff --git a/Telegram/SourceFiles/boxes/share_box.h b/Telegram/SourceFiles/boxes/share_box.h
index 822c7477f..b5d3f5397 100644
--- a/Telegram/SourceFiles/boxes/share_box.h
+++ b/Telegram/SourceFiles/boxes/share_box.h
@@ -12,7 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "ui/effects/animations.h"
 #include "ui/effects/round_checkbox.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 enum class SendMenuType;
 
diff --git a/Telegram/SourceFiles/boxes/username_box.h b/Telegram/SourceFiles/boxes/username_box.h
index 433d9c05c..3a78c6596 100644
--- a/Telegram/SourceFiles/boxes/username_box.h
+++ b/Telegram/SourceFiles/boxes/username_box.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "boxes/abstract_box.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace Ui {
 class UsernameInput;
diff --git a/Telegram/SourceFiles/calls/calls_call.h b/Telegram/SourceFiles/calls/calls_call.h
index 04ade9804..2580b4026 100644
--- a/Telegram/SourceFiles/calls/calls_call.h
+++ b/Telegram/SourceFiles/calls/calls_call.h
@@ -11,7 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "base/bytes.h"
 #include "mtproto/sender.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 
 namespace Media {
 namespace Audio {
diff --git a/Telegram/SourceFiles/core/application.h b/Telegram/SourceFiles/core/application.h
index 57f3ace71..1f68e48a0 100644
--- a/Telegram/SourceFiles/core/application.h
+++ b/Telegram/SourceFiles/core/application.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "core/core_settings.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "mtproto/mtproto_proxy_data.h"
 #include "base/observer.h"
 #include "base/timer.h"
diff --git a/Telegram/SourceFiles/core/utils.cpp b/Telegram/SourceFiles/core/utils.cpp
index fd62a1716..f51c43323 100644
--- a/Telegram/SourceFiles/core/utils.cpp
+++ b/Telegram/SourceFiles/core/utils.cpp
@@ -58,12 +58,6 @@ static_assert(sizeof(MTPdouble) == 8, "Basic types size check failed");
 
 static_assert(sizeof(int) >= 4, "Basic types size check failed");
 
-namespace {
-
-std::atomic<int> GlobalAtomicRequestId = 0;
-
-} // namespace
-
 // Precise timing functions / rand init
 
 struct CRYPTO_dynlock_value {
@@ -206,14 +200,6 @@ namespace ThirdParty {
 	}
 }
 
-int GetNextRequestId() {
-	const auto result = ++GlobalAtomicRequestId;
-	if (result == std::numeric_limits<int>::max() / 2) {
-		GlobalAtomicRequestId = 0;
-	}
-	return result;
-}
-
 int32 *hashSha1(const void *data, uint32 len, void *dest) {
 	return (int32*)SHA1((const uchar*)data, (size_t)len, (uchar*)dest);
 }
diff --git a/Telegram/SourceFiles/core/utils.h b/Telegram/SourceFiles/core/utils.h
index 051ada8d2..44b2d53da 100644
--- a/Telegram/SourceFiles/core/utils.h
+++ b/Telegram/SourceFiles/core/utils.h
@@ -82,8 +82,6 @@ inline QByteArray str_const_toByteArray(const str_const &str) {
 	return QByteArray::fromRawData(str.c_str(), str.size());
 }
 
-int GetNextRequestId();
-
 inline void mylocaltime(struct tm * _Tm, const time_t * _Time) {
 #ifdef Q_OS_WIN
 	localtime_s(_Tm, _Time);
@@ -161,8 +159,6 @@ T rand_value() {
 	return result;
 }
 
-static const QRegularExpression::PatternOptions reMultiline(QRegularExpression::DotMatchesEverythingOption | QRegularExpression::MultilineOption);
-
 template <typename T>
 inline T snap(const T &v, const T &_min, const T &_max) {
 	return (v < _min) ? _min : ((v > _max) ? _max : v);
diff --git a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
index d0b8d5d7e..0015d4501 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.h
@@ -13,7 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/rp_widget.h"
 #include "base/flags.h"
 #include "base/object_ptr.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace Main {
 class Session;
diff --git a/Telegram/SourceFiles/dialogs/dialogs_widget.h b/Telegram/SourceFiles/dialogs/dialogs_widget.h
index 8d99ef5cc..42799d2dd 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_widget.h
+++ b/Telegram/SourceFiles/dialogs/dialogs_widget.h
@@ -13,7 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/scroll_area.h"
 #include "ui/special_buttons.h"
 #include "api/api_single_message_search.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace Main {
 class Session;
diff --git a/Telegram/SourceFiles/export/export_api_wrap.cpp b/Telegram/SourceFiles/export/export_api_wrap.cpp
index ef8f938c6..8a6b29811 100644
--- a/Telegram/SourceFiles/export/export_api_wrap.cpp
+++ b/Telegram/SourceFiles/export/export_api_wrap.cpp
@@ -11,7 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "export/data/export_data_types.h"
 #include "export/output/export_output_result.h"
 #include "export/output/export_output_file.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 #include "base/value_ordering.h"
 #include "base/bytes.h"
 #include <set>
diff --git a/Telegram/SourceFiles/export/export_controller.h b/Telegram/SourceFiles/export/export_controller.h
index 5dc59ad14..aa8afa9a4 100644
--- a/Telegram/SourceFiles/export/export_controller.h
+++ b/Telegram/SourceFiles/export/export_controller.h
@@ -7,9 +7,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include <crl/crl_object_on_queue.h>
 #include "base/variant.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
+
+#include <crl/crl_object_on_queue.h>
 
 namespace Export {
 
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 6729c086e..64aff4a1c 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "mtproto/mtp_instance.h"
 #include "base/weak_ptr.h"
 
diff --git a/Telegram/SourceFiles/mainwidget.h b/Telegram/SourceFiles/mainwidget.h
index cdce6b299..d07cd1ddc 100644
--- a/Telegram/SourceFiles/mainwidget.h
+++ b/Telegram/SourceFiles/mainwidget.h
@@ -13,7 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/effects/animations.h"
 #include "media/player/media_player_float.h"
 #include "data/data_pts_waiter.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 struct HistoryMessageMarkupButton;
 class MainWindow;
diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
index 1d687bbdb..b2ffb0028 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
+++ b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/concurrent_sender.h"
 
 #include "mtproto/mtp_instance.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/facade.h"
 
 namespace MTP {
@@ -135,7 +135,7 @@ void ConcurrentSender::RequestBuilder::setAfter(
 }
 
 mtpRequestId ConcurrentSender::RequestBuilder::send() {
-	const auto requestId = GetNextRequestId();
+	const auto requestId = internal::GetNextRequestId();
 	const auto dcId = _dcId;
 	const auto msCanWait = _canWait;
 	const auto afterRequestId = _afterRequestId;
diff --git a/Telegram/SourceFiles/mtproto/config_loader.h b/Telegram/SourceFiles/mtproto/config_loader.h
index 923dc2e25..476e8f164 100644
--- a/Telegram/SourceFiles/mtproto/config_loader.h
+++ b/Telegram/SourceFiles/mtproto/config_loader.h
@@ -10,7 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "base/weak_ptr.h"
 #include "base/bytes.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace MTP {
 
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index d5328d9d7..854469960 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -11,8 +11,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/details/mtproto_dump_to_text.h"
 #include "mtproto/session.h"
-#include "mtproto/rsa_public_key.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rsa_public_key.h"
+#include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/connection_abstract.h"
 #include "zlib.h"
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 8a6084474..5e151b29a 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/connection_abstract.h"
 #include "mtproto/facade.h"
diff --git a/Telegram/SourceFiles/mtproto/connection_resolving.h b/Telegram/SourceFiles/mtproto/connection_resolving.h
index 4a91657db..ceb9c474e 100644
--- a/Telegram/SourceFiles/mtproto/connection_resolving.h
+++ b/Telegram/SourceFiles/mtproto/connection_resolving.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "mtproto/connection_abstract.h"
 #include "base/timer.h"
 
diff --git a/Telegram/SourceFiles/mtproto/connection_tcp.cpp b/Telegram/SourceFiles/mtproto/connection_tcp.cpp
index 2b73bce79..f46e16c26 100644
--- a/Telegram/SourceFiles/mtproto/connection_tcp.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_tcp.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/connection_tcp.h"
 
-#include "mtproto/mtp_abstract_socket.h"
+#include "mtproto/mtproto_abstract_socket.h"
 #include "base/bytes.h"
 #include "base/openssl_help.h"
 #include "base/qthelp_url.h"
diff --git a/Telegram/SourceFiles/mtproto/connection_tcp.h b/Telegram/SourceFiles/mtproto/connection_tcp.h
index 10da72760..07134f14f 100644
--- a/Telegram/SourceFiles/mtproto/connection_tcp.h
+++ b/Telegram/SourceFiles/mtproto/connection_tcp.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/connection_abstract.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 
 namespace MTP {
 namespace internal {
diff --git a/Telegram/SourceFiles/mtproto/dc_options.h b/Telegram/SourceFiles/mtproto/dc_options.h
index 71d3dec85..1e910f9a6 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.h
+++ b/Telegram/SourceFiles/mtproto/dc_options.h
@@ -9,7 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "base/observer.h"
 #include "base/bytes.h"
-#include "mtproto/rsa_public_key.h"
+#include "mtproto/mtproto_rsa_public_key.h"
 
 #include <QtCore/QReadWriteLock>
 #include <string>
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/dcenter.cpp
index 970ca3f39..65bd84fb9 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/dcenter.cpp
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/dcenter.h"
 
 #include "mtproto/facade.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/mtp_instance.h"
 #include "mtproto/special_config_request.h"
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
index 80cb5b4e9..85d4a55da 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/core_types.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 
 namespace MTP {
 class Instance;
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
index c5738cd48..23dcadbd6 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/core_types.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "mtproto/connection_abstract.h"
 #include "base/basic_types.h"
 #include "base/expected.h"
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 62cd32a3a..c82305c6d 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -14,7 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/special_config_request.h"
 #include "mtproto/connection.h"
 #include "mtproto/sender.h"
-#include "mtproto/rsa_public_key.h"
+#include "mtproto/mtproto_rsa_public_key.h"
 #include "storage/localstorage.h"
 #include "calls/calls_instance.h"
 #include "main/main_session.h" // Session::Exists.
@@ -37,8 +37,22 @@ constexpr auto kCheckKeyEach = 60 * crl::time(1000);
 
 using namespace internal;
 
+std::atomic<int> GlobalAtomicRequestId = 0;
+
 } // namespace
 
+namespace internal {
+
+int GetNextRequestId() {
+	const auto result = ++GlobalAtomicRequestId;
+	if (result == std::numeric_limits<int>::max() / 2) {
+		GlobalAtomicRequestId = 0;
+	}
+	return result;
+}
+
+} // namespace internal
+
 class Instance::Private : private Sender {
 public:
 	Private(not_null<Instance*> instance, not_null<DcOptions*> options, Instance::Mode mode);
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 04a1afb1c..5443745c4 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -7,15 +7,17 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include <map>
-#include <set>
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 
 namespace MTP {
 namespace internal {
+
 class Dcenter;
 class Session;
 class Connection;
+
+[[nodiscard]] int GetNextRequestId();
+
 } // namespace internal
 
 class DcOptions;
@@ -130,7 +132,7 @@ public:
 			ShiftedDcId shiftedDcId = 0,
 			crl::time msCanWait = 0,
 			mtpRequestId afterRequestId = 0) {
-		const auto requestId = GetNextRequestId();
+		const auto requestId = internal::GetNextRequestId();
 		sendSerialized(
 			requestId,
 			SecureRequest::Serialize(request),
@@ -161,7 +163,7 @@ public:
 	mtpRequestId sendProtocolMessage(
 			ShiftedDcId shiftedDcId,
 			const Request &request) {
-		const auto requestId = GetNextRequestId();
+		const auto requestId = internal::GetNextRequestId();
 		sendRequest(
 			requestId,
 			SecureRequest::Serialize(request),
diff --git a/Telegram/SourceFiles/mtproto/mtp_abstract_socket.cpp b/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.cpp
similarity index 84%
rename from Telegram/SourceFiles/mtproto/mtp_abstract_socket.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_abstract_socket.cpp
index 1de6e6654..2f77cd144 100644
--- a/Telegram/SourceFiles/mtproto/mtp_abstract_socket.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.cpp
@@ -5,10 +5,10 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtp_abstract_socket.h"
+#include "mtproto/mtproto_abstract_socket.h"
 
-#include "mtproto/mtp_tcp_socket.h"
-#include "mtproto/mtp_tls_socket.h"
+#include "mtproto/mtproto_tcp_socket.h"
+#include "mtproto/mtproto_tls_socket.h"
 
 namespace MTP {
 namespace internal {
diff --git a/Telegram/SourceFiles/mtproto/mtp_abstract_socket.h b/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.h
similarity index 100%
rename from Telegram/SourceFiles/mtproto/mtp_abstract_socket.h
rename to Telegram/SourceFiles/mtproto/mtproto_abstract_socket.h
diff --git a/Telegram/SourceFiles/mtproto/auth_key.cpp b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
similarity index 64%
rename from Telegram/SourceFiles/mtproto/auth_key.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
index 6df7761c3..b2991a880 100644
--- a/Telegram/SourceFiles/mtproto/auth_key.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
@@ -5,12 +5,11 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 
-extern "C" {
-#include <openssl/aes.h>
-#include <openssl/modes.h>
-} // extern "C"
+#include "base/openssl_help.h"
+
+#include <QtCore/QDataStream>
 
 namespace MTP {
 
@@ -43,59 +42,61 @@ AuthKey::KeyId AuthKey::keyId() const {
 void AuthKey::prepareAES_oldmtp(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const {
 	uint32 x = send ? 0 : 8;
 
-	uchar data_a[16 + 32], sha1_a[20];
-	memcpy(data_a, &msgKey, 16);
-	memcpy(data_a + 16, _key.data() + x, 32);
-	hashSha1(data_a, 16 + 32, sha1_a);
+	bytes::array<20> sha1_a, sha1_b, sha1_c, sha1_d;
+	bytes::array<16 + 32> data_a;
+	memcpy(data_a.data(), &msgKey, 16);
+	memcpy(data_a.data() + 16, _key.data() + x, 32);
+	openssl::Sha1To(sha1_a, data_a);
 
-	uchar data_b[16 + 16 + 16], sha1_b[20];
-	memcpy(data_b, _key.data() + 32 + x, 16);
-	memcpy(data_b + 16, &msgKey, 16);
-	memcpy(data_b + 32, _key.data() + 48 + x, 16);
-	hashSha1(data_b, 16 + 16 + 16, sha1_b);
+	bytes::array<16 + 16 + 16> data_b;
+	memcpy(data_b.data(), _key.data() + 32 + x, 16);
+	memcpy(data_b.data() + 16, &msgKey, 16);
+	memcpy(data_b.data() + 32, _key.data() + 48 + x, 16);
+	openssl::Sha1To(sha1_b, data_b);
 
-	uchar data_c[32 + 16], sha1_c[20];
-	memcpy(data_c, _key.data() + 64 + x, 32);
-	memcpy(data_c + 32, &msgKey, 16);
-	hashSha1(data_c, 32 + 16, sha1_c);
+	bytes::array<32 + 16> data_c;
+	memcpy(data_c.data(), _key.data() + 64 + x, 32);
+	memcpy(data_c.data() + 32, &msgKey, 16);
+	openssl::Sha1To(sha1_c, data_c);
 
-	uchar data_d[16 + 32], sha1_d[20];
-	memcpy(data_d, &msgKey, 16);
-	memcpy(data_d + 16, _key.data() + 96 + x, 32);
-	hashSha1(data_d, 16 + 32, sha1_d);
+	bytes::array<16 + 32> data_d;
+	memcpy(data_d.data(), &msgKey, 16);
+	memcpy(data_d.data() + 16, _key.data() + 96 + x, 32);
+	openssl::Sha1To(sha1_d, data_d);
 
-	auto key = reinterpret_cast<uchar*>(&aesKey);
-	auto iv = reinterpret_cast<uchar*>(&aesIV);
-	memcpy(key, sha1_a, 8);
-	memcpy(key + 8, sha1_b + 8, 12);
-	memcpy(key + 8 + 12, sha1_c + 4, 12);
-	memcpy(iv, sha1_a + 8, 12);
-	memcpy(iv + 12, sha1_b, 8);
-	memcpy(iv + 12 + 8, sha1_c + 16, 4);
-	memcpy(iv + 12 + 8 + 4, sha1_d, 8);
+	auto key = reinterpret_cast<bytes::type*>(&aesKey);
+	auto iv = reinterpret_cast<bytes::type*>(&aesIV);
+	memcpy(key, sha1_a.data(), 8);
+	memcpy(key + 8, sha1_b.data() + 8, 12);
+	memcpy(key + 8 + 12, sha1_c.data() + 4, 12);
+	memcpy(iv, sha1_a.data() + 8, 12);
+	memcpy(iv + 12, sha1_b.data(), 8);
+	memcpy(iv + 12 + 8, sha1_c.data() + 16, 4);
+	memcpy(iv + 12 + 8 + 4, sha1_d.data(), 8);
 }
 
 void AuthKey::prepareAES(const MTPint128 &msgKey, MTPint256 &aesKey, MTPint256 &aesIV, bool send) const {
 	uint32 x = send ? 0 : 8;
 
-	uchar data_a[16 + 36], sha256_a[32];
-	memcpy(data_a, &msgKey, 16);
-	memcpy(data_a + 16, _key.data() + x, 36);
-	hashSha256(data_a, 16 + 36, sha256_a);
+	bytes::array<32> sha256_a, sha256_b;
+	bytes::array<16 + 36> data_a;
+	memcpy(data_a.data(), &msgKey, 16);
+	memcpy(data_a.data() + 16, _key.data() + x, 36);
+	openssl::Sha256To(sha256_a, data_a);
 
-	uchar data_b[36 + 16], sha256_b[32];
-	memcpy(data_b, _key.data() + 40 + x, 36);
-	memcpy(data_b + 36, &msgKey, 16);
-	hashSha256(data_b, 36 + 16, sha256_b);
+	bytes::array<36 + 16> data_b;
+	memcpy(data_b.data(), _key.data() + 40 + x, 36);
+	memcpy(data_b.data() + 36, &msgKey, 16);
+	openssl::Sha256To(sha256_b, data_b);
 
 	auto key = reinterpret_cast<uchar*>(&aesKey);
 	auto iv = reinterpret_cast<uchar*>(&aesIV);
-	memcpy(key, sha256_a, 8);
-	memcpy(key + 8, sha256_b + 8, 16);
-	memcpy(key + 8 + 16, sha256_a + 24, 8);
-	memcpy(iv, sha256_b, 8);
-	memcpy(iv + 8, sha256_a + 8, 16);
-	memcpy(iv + 8 + 16, sha256_b + 24, 8);
+	memcpy(key, sha256_a.data(), 8);
+	memcpy(key + 8, sha256_b.data() + 8, 16);
+	memcpy(key + 8 + 16, sha256_a.data() + 24, 8);
+	memcpy(iv, sha256_b.data(), 8);
+	memcpy(iv + 8, sha256_a.data() + 8, 16);
+	memcpy(iv + 8 + 16, sha256_b.data() + 24, 8);
 }
 
 const void *AuthKey::partForMsgKey(bool send) const {
@@ -135,10 +136,10 @@ void AuthKey::FillData(Data &authKey, bytes::const_span computedAuthKey) {
 }
 
 void AuthKey::countKeyId() {
-	auto sha1 = hashSha1(_key.data(), _key.size());
+	const auto hash = openssl::Sha1(_key);
 
 	// Lower 64 bits = 8 bytes of 20 byte SHA1 hash.
-	_keyId = *reinterpret_cast<KeyId*>(sha1.data() + 12);
+	_keyId = *reinterpret_cast<const KeyId*>(hash.data() + 12);
 }
 
 void aesIgeEncryptRaw(const void *src, void *dst, uint32 len, const void *key, const void *iv) {
diff --git a/Telegram/SourceFiles/mtproto/auth_key.h b/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
similarity index 100%
rename from Telegram/SourceFiles/mtproto/auth_key.h
rename to Telegram/SourceFiles/mtproto/mtproto_auth_key.h
diff --git a/Telegram/SourceFiles/mtproto/mtp_pch.cpp b/Telegram/SourceFiles/mtproto/mtproto_pch.cpp
similarity index 89%
rename from Telegram/SourceFiles/mtproto/mtp_pch.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_pch.cpp
index 3194b80c1..bdad25fc3 100644
--- a/Telegram/SourceFiles/mtproto/mtp_pch.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_pch.cpp
@@ -5,6 +5,6 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtp_pch.h"
+#include "mtproto/mtproto_pch.h"
 
 // Precompiled header helper.
diff --git a/Telegram/SourceFiles/mtproto/mtp_pch.h b/Telegram/SourceFiles/mtproto/mtproto_pch.h
similarity index 100%
rename from Telegram/SourceFiles/mtproto/mtp_pch.h
rename to Telegram/SourceFiles/mtproto/mtproto_pch.h
diff --git a/Telegram/SourceFiles/mtproto/rpc_sender.cpp b/Telegram/SourceFiles/mtproto/mtproto_rpc_sender.cpp
similarity index 78%
rename from Telegram/SourceFiles/mtproto/rpc_sender.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_rpc_sender.cpp
index a3859ec4f..b723fd292 100644
--- a/Telegram/SourceFiles/mtproto/rpc_sender.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_rpc_sender.cpp
@@ -5,25 +5,28 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
+
+#include <QtCore/QRegularExpression>
 
 RPCError::RPCError(const MTPrpcError &error)
 : _code(error.c_rpc_error().verror_code().v) {
 	QString text = qs(error.c_rpc_error().verror_message());
 	if (_code < 0 || _code >= 500) {
-		_type = qsl("INTERNAL_SERVER_ERROR");
+		_type = "INTERNAL_SERVER_ERROR";
 		_description = text;
 	} else {
 		const auto expression = QRegularExpression(
 			"^([A-Z0-9_]+)(: .*)?$",
-			reMultiline);
+			(QRegularExpression::DotMatchesEverythingOption
+				| QRegularExpression::MultilineOption));
 		const auto match = expression.match(text);
 		if (match.hasMatch()) {
 			_type = match.captured(1);
 			_description = match.captured(2).mid(2);
 		} else {
-			_type = qsl("CLIENT_BAD_RPC_ERROR");
-			_description = qsl("Bad rpc error received, text = '") + text + '\'';
+			_type = "CLIENT_BAD_RPC_ERROR";
+			_description = "Bad rpc error received, text = '" + text + '\'';
 		}
 	}
 }
diff --git a/Telegram/SourceFiles/mtproto/rpc_sender.h b/Telegram/SourceFiles/mtproto/mtproto_rpc_sender.h
similarity index 99%
rename from Telegram/SourceFiles/mtproto/rpc_sender.h
rename to Telegram/SourceFiles/mtproto/mtproto_rpc_sender.h
index 4de116548..c3ae32324 100644
--- a/Telegram/SourceFiles/mtproto/rpc_sender.h
+++ b/Telegram/SourceFiles/mtproto/mtproto_rpc_sender.h
@@ -8,8 +8,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "base/flat_set.h"
-#include "core/utils.h"
-#include <rpl/details/callable.h>
 
 class RPCError {
 public:
diff --git a/Telegram/SourceFiles/mtproto/rsa_public_key.cpp b/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.cpp
similarity index 96%
rename from Telegram/SourceFiles/mtproto/rsa_public_key.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.cpp
index 361c9930d..ca10f0a29 100644
--- a/Telegram/SourceFiles/mtproto/rsa_public_key.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.cpp
@@ -5,17 +5,10 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/rsa_public_key.h"
+#include "mtproto/mtproto_rsa_public_key.h"
 
 #include "base/openssl_help.h"
 
-extern "C" {
-#include <openssl/rsa.h>
-#include <openssl/pem.h>
-#include <openssl/bio.h>
-#include <openssl/err.h>
-} // extern "C"
-
 namespace MTP {
 namespace internal {
 namespace {
@@ -234,8 +227,9 @@ void RSAPublicKey::Private::computeFingerprint() {
 	MTP_bytes(ToBytes(n)).write(string);
 	MTP_bytes(ToBytes(e)).write(string);
 
-	uchar sha1Buffer[20];
-	_fingerprint = *(uint64*)(hashSha1(&string[0], string.size() * sizeof(mtpPrime), sha1Buffer) + 3);
+	bytes::array<20> sha1Buffer;
+	openssl::Sha1To(sha1Buffer, bytes::make_span(string));
+	_fingerprint = *(uint64*)(sha1Buffer.data() + 12);
 }
 
 bytes::vector RSAPublicKey::Private::ToBytes(const BIGNUM *number) {
diff --git a/Telegram/SourceFiles/mtproto/rsa_public_key.h b/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.h
similarity index 100%
rename from Telegram/SourceFiles/mtproto/rsa_public_key.h
rename to Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.h
diff --git a/Telegram/SourceFiles/mtproto/mtp_tcp_socket.cpp b/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.cpp
similarity index 99%
rename from Telegram/SourceFiles/mtproto/mtp_tcp_socket.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_tcp_socket.cpp
index 3349cbadd..d2fbd6ad9 100644
--- a/Telegram/SourceFiles/mtproto/mtp_tcp_socket.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.cpp
@@ -5,7 +5,7 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtp_tcp_socket.h"
+#include "mtproto/mtproto_tcp_socket.h"
 
 #include "base/invoke_queued.h"
 
diff --git a/Telegram/SourceFiles/mtproto/mtp_tcp_socket.h b/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.h
similarity index 95%
rename from Telegram/SourceFiles/mtproto/mtp_tcp_socket.h
rename to Telegram/SourceFiles/mtproto/mtproto_tcp_socket.h
index 487b2dcc0..c8919fce2 100644
--- a/Telegram/SourceFiles/mtproto/mtp_tcp_socket.h
+++ b/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/mtp_abstract_socket.h"
+#include "mtproto/mtproto_abstract_socket.h"
 
 namespace MTP {
 namespace internal {
diff --git a/Telegram/SourceFiles/mtproto/mtp_tls_socket.cpp b/Telegram/SourceFiles/mtproto/mtproto_tls_socket.cpp
similarity index 99%
rename from Telegram/SourceFiles/mtproto/mtp_tls_socket.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_tls_socket.cpp
index 691a482cd..8aa38f523 100644
--- a/Telegram/SourceFiles/mtproto/mtp_tls_socket.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_tls_socket.cpp
@@ -5,9 +5,9 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtp_tls_socket.h"
+#include "mtproto/mtproto_tls_socket.h"
 
-#include "mtproto/mtp_tcp_socket.h"
+#include "mtproto/mtproto_tcp_socket.h"
 #include "base/openssl_help.h"
 #include "base/bytes.h"
 #include "base/invoke_queued.h"
diff --git a/Telegram/SourceFiles/mtproto/mtp_tls_socket.h b/Telegram/SourceFiles/mtproto/mtproto_tls_socket.h
similarity index 97%
rename from Telegram/SourceFiles/mtproto/mtp_tls_socket.h
rename to Telegram/SourceFiles/mtproto/mtproto_tls_socket.h
index df8742b34..a93ef4014 100644
--- a/Telegram/SourceFiles/mtproto/mtp_tls_socket.h
+++ b/Telegram/SourceFiles/mtproto/mtproto_tls_socket.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/mtp_abstract_socket.h"
+#include "mtproto/mtproto_abstract_socket.h"
 
 namespace MTP {
 namespace internal {
diff --git a/Telegram/SourceFiles/mtproto/sender.h b/Telegram/SourceFiles/mtproto/sender.h
index ab6521735..3e1fd6c71 100644
--- a/Telegram/SourceFiles/mtproto/sender.h
+++ b/Telegram/SourceFiles/mtproto/sender.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "base/variant.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/mtp_instance.h"
 #include "mtproto/facade.h"
 
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 3d525cf7c..4ef0ecdd4 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -10,7 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/connection.h"
 #include "mtproto/dcenter.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "base/unixtime.h"
 #include "base/openssl_help.h"
 #include "core/crash_reports.h"
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 1d6ffb68c..cc5a03d6d 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "base/timer.h"
-#include "mtproto/rpc_sender.h"
+#include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/mtproto_proxy_data.h"
 
 #include <QtCore/QTimer>
diff --git a/Telegram/SourceFiles/mtproto/special_config_request.cpp b/Telegram/SourceFiles/mtproto/special_config_request.cpp
index 362a21d7a..992c436c6 100644
--- a/Telegram/SourceFiles/mtproto/special_config_request.cpp
+++ b/Telegram/SourceFiles/mtproto/special_config_request.cpp
@@ -7,9 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/special_config_request.h"
 
-#include "mtproto/rsa_public_key.h"
+#include "mtproto/mtproto_rsa_public_key.h"
 #include "mtproto/dc_options.h"
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 #include "base/unixtime.h"
 #include "base/openssl_help.h"
 #include "base/call_delayed.h"
diff --git a/Telegram/SourceFiles/passport/passport_encryption.cpp b/Telegram/SourceFiles/passport/passport_encryption.cpp
index c37e53872..ce83fa5d8 100644
--- a/Telegram/SourceFiles/passport/passport_encryption.cpp
+++ b/Telegram/SourceFiles/passport/passport_encryption.cpp
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "passport/passport_encryption.h"
 
 #include "base/openssl_help.h"
-#include "mtproto/rsa_public_key.h"
+#include "mtproto/mtproto_rsa_public_key.h"
 
 #include <QtCore/QJsonDocument>
 #include <QtCore/QJsonArray>
diff --git a/Telegram/SourceFiles/storage/serialize_common.h b/Telegram/SourceFiles/storage/serialize_common.h
index 679c0fece..a1acb9b6b 100644
--- a/Telegram/SourceFiles/storage/serialize_common.h
+++ b/Telegram/SourceFiles/storage/serialize_common.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/auth_key.h"
+#include "mtproto/mtproto_auth_key.h"
 
 namespace Serialize {
 
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index bbc7a3e17..99ec10634 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -19,8 +19,8 @@
     'variables': {
       'src_loc': '../SourceFiles',
       'res_loc': '../Resources',
-      'pch_source': '<(src_loc)/mtproto/mtp_pch.cpp',
-      'pch_header': '<(src_loc)/mtproto/mtp_pch.h',
+      'pch_source': '<(src_loc)/mtproto/mtproto_pch.cpp',
+      'pch_header': '<(src_loc)/mtproto/mtproto_pch.h',
     },
     'defines': [
     ],
@@ -40,16 +40,22 @@
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.h',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.cpp',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.h',
+      '<(src_loc)/mtproto/mtproto_abstract_socket.cpp',
+      '<(src_loc)/mtproto/mtproto_abstract_socket.h',
+      '<(src_loc)/mtproto/mtproto_auth_key.cpp',
+      '<(src_loc)/mtproto/mtproto_auth_key.h',
       '<(src_loc)/mtproto/mtproto_dh_utils.cpp',
       '<(src_loc)/mtproto/mtproto_dh_utils.h',
       '<(src_loc)/mtproto/mtproto_proxy_data.cpp',
       '<(src_loc)/mtproto/mtproto_proxy_data.h',
-      '<(src_loc)/mtproto/mtp_abstract_socket.cpp',
-      '<(src_loc)/mtproto/mtp_abstract_socket.h',
-      '<(src_loc)/mtproto/mtp_tcp_socket.cpp',
-      '<(src_loc)/mtproto/mtp_tcp_socket.h',
-      '<(src_loc)/mtproto/mtp_tls_socket.cpp',
-      '<(src_loc)/mtproto/mtp_tls_socket.h',
+      '<(src_loc)/mtproto/mtproto_rsa_public_key.cpp',
+      '<(src_loc)/mtproto/mtproto_rsa_public_key.h',
+      '<(src_loc)/mtproto/mtproto_rpc_sender.cpp',
+      '<(src_loc)/mtproto/mtproto_rpc_sender.h',
+      '<(src_loc)/mtproto/mtproto_tcp_socket.cpp',
+      '<(src_loc)/mtproto/mtproto_tcp_socket.h',
+      '<(src_loc)/mtproto/mtproto_tls_socket.cpp',
+      '<(src_loc)/mtproto/mtproto_tls_socket.h',
     ],
   }],
 }
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index ca89de7a3..e7ccceed3 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -533,8 +533,6 @@
 <(src_loc)/media/view/media_view_group_thumbs.h
 <(src_loc)/media/view/media_view_overlay_widget.cpp
 <(src_loc)/media/view/media_view_overlay_widget.h
-<(src_loc)/mtproto/auth_key.cpp
-<(src_loc)/mtproto/auth_key.h
 <(src_loc)/mtproto/concurrent_sender.cpp
 <(src_loc)/mtproto/concurrent_sender.h
 <(src_loc)/mtproto/config_loader.cpp
@@ -561,10 +559,6 @@
 <(src_loc)/mtproto/facade.h
 <(src_loc)/mtproto/mtp_instance.cpp
 <(src_loc)/mtproto/mtp_instance.h
-<(src_loc)/mtproto/rsa_public_key.cpp
-<(src_loc)/mtproto/rsa_public_key.h
-<(src_loc)/mtproto/rpc_sender.cpp
-<(src_loc)/mtproto/rpc_sender.h
 <(src_loc)/mtproto/sender.h
 <(src_loc)/mtproto/session.cpp
 <(src_loc)/mtproto/session.h
diff --git a/Telegram/lib_base b/Telegram/lib_base
index bdc4127ff..95ea34f59 160000
--- a/Telegram/lib_base
+++ b/Telegram/lib_base
@@ -1 +1 @@
-Subproject commit bdc4127ff5d5a14eb9d04986725ef7ec94e6d807
+Subproject commit 95ea34f59c2e747343aef9c78dd1afbd3fa086c2

From d9fc3619c2a5dd3d680e695239fc4d801a0ad742 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 18 Nov 2019 15:53:37 +0300
Subject: [PATCH 29/91] Remove all signals from ConnectionPrivate.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 240 ++++++-----------
 Telegram/SourceFiles/mtproto/connection.h     |  65 ++---
 Telegram/SourceFiles/mtproto/dcenter.cpp      |  19 +-
 Telegram/SourceFiles/mtproto/dcenter.h        |   9 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  24 +-
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   5 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 255 ++++++++++++++----
 Telegram/SourceFiles/mtproto/session.h        |  79 ++++--
 8 files changed, 399 insertions(+), 297 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 854469960..1ab49e795 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -23,15 +23,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/qthelp_url.h"
 #include "base/unixtime.h"
 
-extern "C" {
-#include <openssl/bn.h>
-#include <openssl/err.h>
-#include <openssl/aes.h>
-#include <openssl/sha.h>
-#include <openssl/md5.h>
-#include <openssl/rand.h>
-} // extern "C"
-
 #ifdef small
 #undef small
 #endif // small
@@ -107,7 +98,7 @@ Connection::~Connection() {
 	}
 }
 
-void Connection::start(SessionData *sessionData, ShiftedDcId shiftedDcId) {
+void Connection::start(std::shared_ptr<SessionData> sessionData, ShiftedDcId shiftedDcId) {
 	Expects(_thread == nullptr && _private == nullptr);
 
 	_thread = std::make_unique<QThread>();
@@ -115,7 +106,7 @@ void Connection::start(SessionData *sessionData, ShiftedDcId shiftedDcId) {
 		_instance,
 		_thread.get(),
 		this,
-		sessionData,
+		std::move(sessionData),
 		shiftedDcId);
 
 	// will be deleted in the thread::finished signal
@@ -214,10 +205,7 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 }
 
 void ConnectionPrivate::destroyAllConnections() {
-	{
-		QReadLocker lockFinished(&_sessionDataMutex);
-		clearKeyCreatorOnFail();
-	}
+	clearKeyCreatorOnFail();
 	_waitForBetterTimer.cancel();
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
@@ -229,7 +217,7 @@ ConnectionPrivate::ConnectionPrivate(
 	not_null<Instance*> instance,
 	not_null<QThread*> thread,
 	not_null<Connection*> owner,
-	not_null<SessionData*> data,
+	std::shared_ptr<SessionData> data,
 	ShiftedDcId shiftedDcId)
 : QObject(nullptr)
 , _instance(instance)
@@ -244,7 +232,7 @@ ConnectionPrivate::ConnectionPrivate(
 , _waitForReceived(kMinReceiveTimeout)
 , _waitForConnected(kMinConnectedTimeout)
 , _pingSender(thread, [=] { sendPingByTimer(); })
-, _sessionData(data) {
+, _sessionData(std::move(data)) {
 	Expects(_shiftedDcId != 0);
 
 	moveToThread(thread);
@@ -254,33 +242,16 @@ ConnectionPrivate::ConnectionPrivate(
 
 	connect(_sessionData->owner(), SIGNAL(authKeyChanged()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
 	connect(_sessionData->owner(), SIGNAL(needToRestart()), this, SLOT(restartNow()), Qt::QueuedConnection);
-	connect(this, SIGNAL(needToReceive()), _sessionData->owner(), SLOT(tryToReceive()), Qt::QueuedConnection);
-	connect(this, SIGNAL(stateChanged(qint32)), _sessionData->owner(), SLOT(onConnectionStateChange(qint32)), Qt::QueuedConnection);
 	connect(_sessionData->owner(), SIGNAL(needToSend()), this, SLOT(tryToSend()), Qt::QueuedConnection);
 	connect(_sessionData->owner(), SIGNAL(needToPing()), this, SLOT(onPingSendForce()), Qt::QueuedConnection);
-	connect(this, SIGNAL(sessionResetDone()), _sessionData->owner(), SLOT(onResetDone()), Qt::QueuedConnection);
-
-	static bool _registered = false;
-	if (!_registered) {
-		_registered = true;
-		qRegisterMetaType<QVector<quint64> >("QVector<quint64>");
-	}
-
-	connect(this, SIGNAL(needToSendAsync()), _sessionData->owner(), SLOT(needToResumeAndSend()), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendAnythingAsync(qint64)), _sessionData->owner(), SLOT(sendAnything(qint64)), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendHttpWaitAsync()), _sessionData->owner(), SLOT(sendAnything()), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendPongAsync(quint64,quint64)), _sessionData->owner(), SLOT(sendPong(quint64,quint64)), Qt::QueuedConnection);
-	connect(this, SIGNAL(sendMsgsStateInfoAsync(quint64, QByteArray)), _sessionData->owner(), SLOT(sendMsgsStateInfo(quint64,QByteArray)), Qt::QueuedConnection);
-	connect(this, SIGNAL(resendAsync(quint64,qint64,bool,bool)), _sessionData->owner(), SLOT(resend(quint64,qint64,bool,bool)), Qt::QueuedConnection);
-	connect(this, SIGNAL(resendManyAsync(QVector<quint64>,qint64,bool,bool)), _sessionData->owner(), SLOT(resendMany(QVector<quint64>,qint64,bool,bool)), Qt::QueuedConnection);
-	connect(this, SIGNAL(resendAllAsync()), _sessionData->owner(), SLOT(resendAll()), Qt::QueuedConnection);
 }
 
 ConnectionPrivate::~ConnectionPrivate() {
+	clearKeyCreatorOnFail();
+
 	Expects(_finished);
 	Expects(!_connection);
 	Expects(_testConnections.empty());
-	Expects(!_keyCreator);
 }
 
 void ConnectionPrivate::onConfigLoaded() {
@@ -324,6 +295,7 @@ bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 		QReadLocker lock(&stateConnMutex);
 		if (_state != ifState) return false;
 	}
+
 	QWriteLocker lock(&stateConnMutex);
 	if (_state == state) return false;
 	_state = state;
@@ -332,7 +304,9 @@ bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 		_retryTimer.callOnce(_retryTimeout);
 		_retryWillFinish = crl::now() + _retryTimeout;
 	}
-	emit stateChanged(state);
+	lock.unlock();
+
+	_sessionData->queueConnectionStateChange(state);
 	return true;
 }
 
@@ -465,7 +439,7 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 		_sessionData->stateRequestMap().clear();
 	}
 
-	emit sessionResetDone();
+	_sessionData->queueResetDone();
 }
 
 mtpMsgId ConnectionPrivate::prepareToSend(
@@ -570,12 +544,11 @@ mtpMsgId ConnectionPrivate::placeToContainer(SecureRequest &toSendRequest, mtpMs
 }
 
 void ConnectionPrivate::tryToSend() {
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData || !_connection || !_keyId) {
+	if (!_connection || !_keyId) {
 		return;
 	}
 
-	auto needsLayer = !_sessionData->owner()->connectionInited();
+	auto needsLayer = !_sessionData->connectionInited();
 	auto state = getState();
 	auto sendOnlyFirstPing = (state != ConnectedState);
 	if (sendOnlyFirstPing && !_pingIdToSend) {
@@ -926,16 +899,10 @@ void ConnectionPrivate::tryToSend() {
 			toSend.clear();
 		}
 	}
-	sendSecureRequest(
-		std::move(toSendRequest),
-		needAnyResponse,
-		lockFinished);
+	sendSecureRequest(std::move(toSendRequest), needAnyResponse);
 }
 
 void ConnectionPrivate::retryByTimer() {
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData) return;
-
 	if (_retryTimeout < 3) {
 		++_retryTimeout;
 	} else if (_retryTimeout == 3) {
@@ -959,17 +926,11 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 		return;
 	}
 
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData) {
-		DEBUG_LOG(("MTP Error: "
-			"connectToServer() called for stopped connection!"));
-		return;
-	}
 	_connectionOptions = std::make_unique<ConnectionOptions>(
 		_sessionData->connectionOptions());
+
 	// #TODO race.
-	const auto hasKey = (_sessionData->owner()->getKey() != nullptr);
-	lockFinished.unlock();
+	const auto hasKey = (_sessionData->getKey() != nullptr);
 
 	const auto bareDc = BareDcId(_shiftedDcId);
 	_dcType = _instance->dcOptions()->dcType(_shiftedDcId);
@@ -1063,6 +1024,7 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 	_waitForConnectedTimer.cancel();
 
 	setState(ConnectingState);
+
 	_pingId = _pingMsgId = _pingIdToSend = _pingSendAt = 0;
 	_pingSender.cancel();
 
@@ -1070,25 +1032,23 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 }
 
 void ConnectionPrivate::restart() {
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData) return;
-
 	DEBUG_LOG(("MTP Info: restarting Connection"));
 
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
 
-	lockFinished.unlock();
 	doDisconnect();
 
-	lockFinished.relock();
-	if (_sessionData && _needSessionReset) {
+	if (_needSessionReset) {
 		resetSession();
 	}
 	_restarted = true;
-	if (_retryTimer.isActive()) return;
+	if (_retryTimer.isActive()) {
+		return;
+	}
 
 	DEBUG_LOG(("MTP Info: restart timeout: %1ms").arg(_retryTimeout));
+
 	setState(-_retryTimeout);
 }
 
@@ -1152,7 +1112,7 @@ void ConnectionPrivate::sendPingByTimer() {
 			_pingSender.callOnce(mustSendTill - now);
 		}
 	} else {
-		emit needToSendAsync();
+		_sessionData->queueNeedToResumeAndSend();
 	}
 }
 
@@ -1244,16 +1204,8 @@ void ConnectionPrivate::requestCDNConfig() {
 }
 
 void ConnectionPrivate::handleReceived() {
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData) return;
-
 	onReceivedSome();
 
-	const auto restartOnError = [&] {
-		lockFinished.unlock();
-		restart();
-	};
-
 	while (!_connection->received().empty()) {
 		auto intsBuffer = std::move(_connection->received().front());
 		_connection->received().pop_front();
@@ -1268,13 +1220,13 @@ void ConnectionPrivate::handleReceived() {
 			LOG(("TCP Error: bad message received, len %1").arg(intsCount * kIntSize));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(ints, intsCount * kIntSize).str()));
 
-			return restartOnError();
+			return restart();
 		}
 		if (_keyId != *(uint64*)ints) {
 			LOG(("TCP Error: bad auth_key_id %1 instead of %2 received").arg(_keyId).arg(*(uint64*)ints));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(ints, intsCount * kIntSize).str()));
 
-			return restartOnError();
+			return restart();
 		}
 
 		auto encryptedInts = ints + kExternalHeaderIntsCount;
@@ -1301,7 +1253,7 @@ void ConnectionPrivate::handleReceived() {
 			LOG(("TCP Error: bad messageLength %1").arg(messageLength));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(ints, intsCount * kIntSize).str()));
 
-			return restartOnError();
+			return restart();
 
 		}
 		auto fullDataLength = kEncryptedHeaderIntsCount * kIntSize + messageLength; // Without padding.
@@ -1322,7 +1274,7 @@ void ConnectionPrivate::handleReceived() {
 			LOG(("TCP Error: bad SHA1 hash after aesDecrypt in message."));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encryptedInts, encryptedBytesCount).str()));
 
-			return restartOnError();
+			return restart();
 		}
 #else // TDESKTOP_MTPROTO_OLD
 		constexpr auto kMinPaddingSize = 12U;
@@ -1342,7 +1294,7 @@ void ConnectionPrivate::handleReceived() {
 			LOG(("TCP Error: bad SHA256 hash after aesDecrypt in message"));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encryptedInts, encryptedBytesCount).str()));
 
-			return restartOnError();
+			return restart();
 		}
 #endif // TDESKTOP_MTPROTO_OLD
 
@@ -1350,7 +1302,7 @@ void ConnectionPrivate::handleReceived() {
 			LOG(("TCP Error: bad msg_len received %1, data size: %2").arg(messageLength).arg(encryptedBytesCount));
 			TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encryptedInts, encryptedBytesCount).str()));
 
-			return restartOnError();
+			return restart();
 		}
 
 		TCP_LOG(("TCP Info: decrypted message %1,%2,%3 is %4 len").arg(msgId).arg(seqNo).arg(Logs::b(needAck)).arg(fullDataLength));
@@ -1360,7 +1312,7 @@ void ConnectionPrivate::handleReceived() {
 			LOG(("MTP Error: bad server session received"));
 			TCP_LOG(("MTP Error: bad server session %1 instead of %2 in message received").arg(session).arg(serverSession));
 
-			return restartOnError();
+			return restart();
 		}
 
 		const auto serverTime = int32(msgId >> 32);
@@ -1369,7 +1321,7 @@ void ConnectionPrivate::handleReceived() {
 		if (!isReply && ((msgId & 0x03) != 3)) {
 			LOG(("MTP Error: bad msg_id %1 in message received").arg(msgId));
 
-			return restartOnError();
+			return restart();
 		}
 
 		bool badTime = false;
@@ -1384,11 +1336,10 @@ void ConnectionPrivate::handleReceived() {
 			if (!badTime) {
 				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2, updating...").arg(serverSalt).arg(mySalt));
 				_sessionData->setSalt(serverSalt);
-				if (setState(ConnectedState, ConnectingState)) { // only connected
-					if (_restarted) {
-						emit resendAllAsync();
-						_restarted = false;
-					}
+
+				if (setState(ConnectedState, ConnectingState) && _restarted) {
+					_sessionData->queueResendAll();
+					_restarted = false;
 				}
 			} else {
 				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2").arg(serverSalt).arg(mySalt));
@@ -1419,29 +1370,24 @@ void ConnectionPrivate::handleReceived() {
 		}
 
 		// send acks
-		uint32 toAckSize = _ackRequestData.size();
-		if (toAckSize) {
+		if (const auto toAckSize = _ackRequestData.size()) {
 			DEBUG_LOG(("MTP Info: will send %1 acks, ids: %2").arg(toAckSize).arg(LogIdsVector(_ackRequestData)));
-			emit sendAnythingAsync(kAckSendWaiting);
+			_sessionData->queueSendAnything(kAckSendWaiting);
 		}
 
-		bool emitSignal = false;
-		{
-			QReadLocker locker(_sessionData->haveReceivedMutex());
-			emitSignal = !_sessionData->haveReceivedResponses().isEmpty() || !_sessionData->haveReceivedUpdates().isEmpty();
-			if (emitSignal) {
-				DEBUG_LOG(("MTP Info: emitting needToReceive() - need to parse in another thread, %1 responses, %2 updates.").arg(_sessionData->haveReceivedResponses().size()).arg(_sessionData->haveReceivedUpdates().size()));
-			}
-		}
+		auto lock = QReadLocker(_sessionData->haveReceivedMutex());
+		const auto tryToReceive = !_sessionData->haveReceivedResponses().isEmpty() || !_sessionData->haveReceivedUpdates().isEmpty();
+		lock.unlock();
 
-		if (emitSignal) {
-			emit needToReceive();
+		if (tryToReceive) {
+			DEBUG_LOG(("MTP Info: queueTryToReceive() - need to parse in another thread, %1 responses, %2 updates.").arg(_sessionData->haveReceivedResponses().size()).arg(_sessionData->haveReceivedUpdates().size()));
+			_sessionData->queueTryToReceive();
 		}
 
 		if (res != HandleResult::Success && res != HandleResult::Ignored) {
 			_needSessionReset = (res == HandleResult::ResetSession);
 
-			return restartOnError();
+			return restart();
 		}
 		_retryTimeout = 1; // reset restart() timer
 
@@ -1449,12 +1395,12 @@ void ConnectionPrivate::handleReceived() {
 
 		if (!wasConnected) {
 			if (getState() == ConnectedState) {
-				emit needToSendAsync();
+				_sessionData->queueNeedToResumeAndSend();
 			}
 		}
 	}
 	if (_connection->needHttpWait()) {
-		emit sendHttpWaitAsync();
+		_sessionData->queueSendAnything();
 	}
 }
 
@@ -1679,7 +1625,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 
 		if (setState(ConnectedState, ConnectingState)) { // maybe only connected
 			if (_restarted) {
-				emit resendAllAsync();
+				_sessionData->queueResendAll();
 				_restarted = false;
 			}
 		}
@@ -1741,7 +1687,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				info[i] = state;
 			}
 		}
-		emit sendMsgsStateInfoAsync(msgId, info);
+		_sessionData->queueSendMsgsStateInfo(msgId, info);
 	} return HandleResult::Success;
 
 	case mtpc_msgs_state_info: {
@@ -2273,32 +2219,45 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 	}
 }
 
-void ConnectionPrivate::resend(quint64 msgId, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo) {
-	if (msgId == _pingMsgId) return;
-	emit resendAsync(msgId, msCanWait, forceContainer, sendMsgStateInfo);
+void ConnectionPrivate::resend(
+		mtpMsgId msgId,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo) {
+	if (msgId == _pingMsgId) {
+		return;
+	}
+	_sessionData->queueResend(
+		msgId,
+		msCanWait,
+		forceContainer,
+		sendMsgStateInfo);
 }
 
-void ConnectionPrivate::resendMany(QVector<quint64> msgIds, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo) {
+void ConnectionPrivate::resendMany(
+		QVector<mtpMsgId> msgIds,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo) {
 	for (int32 i = 0, l = msgIds.size(); i < l; ++i) {
 		if (msgIds.at(i) == _pingMsgId) {
 			msgIds.remove(i);
 			--l;
 		}
 	}
-	emit resendManyAsync(msgIds, msCanWait, forceContainer, sendMsgStateInfo);
+	_sessionData->queueResendMany(
+		std::move(msgIds),
+		msCanWait,
+		forceContainer,
+		sendMsgStateInfo);
 }
 
 void ConnectionPrivate::onConnected(
 		not_null<AbstractConnection*> connection) {
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData) return;
-
 	disconnect(connection, &AbstractConnection::connected, nullptr, nullptr);
 	if (!connection->isConnected()) {
 		LOG(("Connection Error: not connected in onConnected(), "
 			"state: %1").arg(connection->debugState()));
-
-		lockFinished.unlock();
 		return restart();
 	}
 
@@ -2323,8 +2282,6 @@ void ConnectionPrivate::onConnected(
 		_waitForBetterTimer.cancel();
 		_connection = std::move(i->data);
 		_testConnections.clear();
-
-		lockFinished.unlock();
 		checkAuthKey();
 	}
 }
@@ -2384,13 +2341,16 @@ void ConnectionPrivate::checkAuthKey() {
 }
 
 void ConnectionPrivate::updateAuthKey() {
-	QReadLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData || _keyCreator) {
+	if (_keyCreator) {
 		return;
 	}
 
 	DEBUG_LOG(("AuthKey Info: Connection updating key from Session, dc %1").arg(_shiftedDcId));
-	_key = _sessionData->owner()->getKey();
+	applyAuthKey(_sessionData->getKey());
+}
+
+void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&key) {
+	_key = std::move(key);
 	const auto newKeyId = _key ? _key->keyId() : 0;
 	if (newKeyId) {
 		if (_keyId == newKeyId) {
@@ -2406,7 +2366,6 @@ void ConnectionPrivate::updateAuthKey() {
 		Assert(already != newKeyId);
 		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
 
-		lockFinished.unlock();
 		restart();
 		return;
 	}
@@ -2420,11 +2379,10 @@ void ConnectionPrivate::updateAuthKey() {
 		LOG(("MTP Error: No key %1 in updateAuthKey() for destroying.").arg(_shiftedDcId));
 		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
 		return;
-	} else if (!_sessionData->owner()->acquireKeyCreation()) {
+	} else if (!_sessionData->acquireKeyCreation()) {
 		DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), but someone is creating already."));
 		return;
 	}
-	lockFinished.unlock();
 
 	DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), creating."));
 	createDcKey();
@@ -2435,9 +2393,6 @@ void ConnectionPrivate::createDcKey() {
 	using Error = DcKeyCreator::Error;
 	auto delegate = DcKeyCreator::Delegate();
 	delegate.done = [=](base::expected<Result, Error> result) {
-		QReadLocker lockFinished(&_sessionDataMutex);
-		if (!_sessionData) return;
-
 		if (result) {
 			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(result->key->keyId()).arg(result->serverSalt));
 
@@ -2445,10 +2400,8 @@ void ConnectionPrivate::createDcKey() {
 			_sessionData->clearForNewKey(_instance);
 
 			_keyCreator = nullptr;
-			_sessionData->owner()->releaseKeyCreationOnDone(
-				std::move(result->key));
-
-			updateAuthKey();
+			_sessionData->releaseKeyCreationOnDone(result->key);
+			applyAuthKey(std::move(result->key));
 			return;
 		}
 		clearKeyCreatorOnFail();
@@ -2484,14 +2437,13 @@ void ConnectionPrivate::authKeyChecked() {
 	if (_sessionData->getSalt()) {
 		setState(ConnectedState);
 		if (_restarted) {
-			emit resendAllAsync();
+			_sessionData->queueResendAll();
 			_restarted = false;
 		}
 	} // else receive salt in bad_server_salt first, then try to send all the requests
 
 	_pingIdToSend = rand_value<uint64>(); // get server_salt
-
-	emit needToSendAsync();
+	_sessionData->queueNeedToResumeAndSend();
 }
 
 void ConnectionPrivate::onError(
@@ -2537,20 +2489,15 @@ void ConnectionPrivate::handleError(int errorCode) {
 
 void ConnectionPrivate::destroyCdnKey() {
 	if (_key) {
-		QReadLocker lockFinished(&_sessionDataMutex);
-		if (_sessionData) {
-			_sessionData->owner()->destroyCdnKey(_keyId);
-		}
+		_sessionData->destroyCdnKey(_keyId);
 	}
 	_key = nullptr;
 	_keyId = 0;
-
 }
 
 bool ConnectionPrivate::sendSecureRequest(
 		SecureRequest &&request,
-		bool needAnyResponse,
-		QReadLocker &lockFinished) {
+		bool needAnyResponse) {
 #ifdef TDESKTOP_MTPROTO_OLD
 	const auto oldPadding = true;
 #else // TDESKTOP_MTPROTO_OLD
@@ -2658,24 +2605,15 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 	return 0;
 }
 
-// _sessionDataMutex must be locked for read.
 void ConnectionPrivate::clearKeyCreatorOnFail() {
-	if (_keyCreator) {
-		_keyCreator = nullptr;
-
-		Assert(_sessionData != nullptr);
-		_sessionData->owner()->releaseKeyCreationOnFail();
+	if (!_keyCreator) {
+		return;
 	}
+	_keyCreator = nullptr;
+	_sessionData->releaseKeyCreationOnFail();
 }
 
 void ConnectionPrivate::stop() {
-	QWriteLocker lockFinished(&_sessionDataMutex);
-	if (!_sessionData) {
-		Assert(_keyCreator == nullptr);
-		return;
-	}
-	clearKeyCreatorOnFail();
-	_sessionData = nullptr;
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 5e151b29a..78c2217a8 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -21,7 +21,7 @@ class DcKeyChecker;
 } // namespace details
 
 // How much time to wait for some more requests, when sending msg acks.
-constexpr auto kAckSendWaiting = crl::time(10000);
+constexpr auto kAckSendWaiting = 10 * crl::time(1000);
 
 class Instance;
 
@@ -43,7 +43,7 @@ public:
 	Connection(not_null<Instance*> instance);
 	~Connection();
 
-	void start(SessionData *data, ShiftedDcId shiftedDcId);
+	void start(std::shared_ptr<SessionData> data, ShiftedDcId shiftedDcId);
 
 	void kill();
 	void waitTillFinish();
@@ -68,7 +68,7 @@ public:
 		not_null<Instance*> instance,
 		not_null<QThread*> thread,
 		not_null<Connection*> owner,
-		not_null<SessionData*> data,
+		std::shared_ptr<SessionData> data,
 		ShiftedDcId shiftedDcId);
 	~ConnectionPrivate();
 
@@ -79,21 +79,6 @@ public:
 	int32 getState() const;
 	QString transport() const;
 
-signals:
-	void needToReceive();
-	void needToRestart();
-	void stateChanged(qint32 newState);
-	void sessionResetDone();
-
-	void needToSendAsync();
-	void sendAnythingAsync(qint64 msWait);
-	void sendHttpWaitAsync();
-	void sendPongAsync(quint64 msgId, quint64 pingId);
-	void sendMsgsStateInfoAsync(quint64 msgId, QByteArray data);
-	void resendAsync(quint64 msgId, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo);
-	void resendManyAsync(QVector<quint64> msgIds, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo);
-	void resendAllAsync();
-
 public slots:
 	void restartNow();
 
@@ -112,6 +97,15 @@ private:
 		ConnectionPointer data;
 		int priority = 0;
 	};
+
+	enum class HandleResult {
+		Success,
+		Ignored,
+		RestartConnection,
+		ResetSession,
+		ParseError,
+	};
+
 	void connectToServer(bool afterConfig = false);
 	void connectingTimedOut();
 	void doDisconnect();
@@ -135,8 +129,6 @@ private:
 	void waitBetterFailed();
 	void markConnectionOld();
 	void sendPingByTimer();
-
-	// Locks _sessionDataMutex.
 	void destroyAllConnections();
 
 	void confirmBestConnection();
@@ -151,23 +143,14 @@ private:
 	mtpMsgId prepareToSend(SecureRequest &request, mtpMsgId currentLastId);
 	mtpMsgId replaceMsgId(SecureRequest &request, mtpMsgId newId);
 
-	bool sendSecureRequest(
-		SecureRequest &&request,
-		bool needAnyResponse,
-		QReadLocker &lockFinished);
+	bool sendSecureRequest(SecureRequest &&request, bool needAnyResponse);
 	mtpRequestId wasSent(mtpMsgId msgId) const;
 
-	enum class HandleResult {
-		Success,
-		Ignored,
-		RestartConnection,
-		ResetSession,
-		ParseError,
-	};
 	[[nodiscard]] HandleResult handleOneReceived(const mtpPrime *from, const mtpPrime *end, uint64 msgId, int32 serverTime, uint64 serverSalt, bool badTime);
 	mtpBuffer ungzip(const mtpPrime *from, const mtpPrime *end) const;
 	void handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked);
 
+	// _sessionDataMutex must be locked for read.
 	bool setState(int32 state, int32 ifState = Connection::UpdateAlways);
 
 	void appendTestConnection(
@@ -182,19 +165,26 @@ private:
 	// remove msgs with such ids from sessionData->haveSent, add to sessionData->wereAcked
 	void requestsAcked(const QVector<MTPlong> &ids, bool byResponse = false);
 
-	void resend(quint64 msgId, qint64 msCanWait = 0, bool forceContainer = false, bool sendMsgStateInfo = false);
-	void resendMany(QVector<quint64> msgIds, qint64 msCanWait = 0, bool forceContainer = false, bool sendMsgStateInfo = false);
+	void resend(
+		mtpMsgId msgId,
+		crl::time msCanWait = 0,
+		bool forceContainer = false,
+		bool sendMsgStateInfo = false);
+	void resendMany(
+		QVector<mtpMsgId> msgIds,
+		crl::time msCanWait = 0,
+		bool forceContainer = false,
+		bool sendMsgStateInfo = false);
 
 	void createDcKey();
 	void resetSession();
 	void checkAuthKey();
 	void authKeyChecked();
 	void destroyCdnKey();
-
-	// _sessionDataMutex must be locked for read.
 	void clearKeyCreatorOnFail();
+	void applyAuthKey(AuthKeyPtr &&key);
 
-	not_null<Instance*> _instance;
+	const not_null<Instance*> _instance;
 	DcType _dcType = DcType::Regular;
 
 	mutable QReadWriteLock stateConnMutex;
@@ -236,8 +226,7 @@ private:
 
 	AuthKeyPtr _key;
 	uint64 _keyId = 0;
-	QReadWriteLock _sessionDataMutex;
-	SessionData *_sessionData = nullptr;
+	std::shared_ptr<SessionData> _sessionData;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 
 	std::unique_ptr<details::DcKeyCreator> _keyCreator;
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/dcenter.cpp
index 65bd84fb9..fa2f10d8a 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/dcenter.cpp
@@ -37,8 +37,8 @@ AuthKeyPtr Dcenter::getKey() const {
 	return _key;
 }
 
-void Dcenter::destroyCdnKey(uint64 keyId) {
-	destroyKey(keyId);
+bool Dcenter::destroyCdnKey(uint64 keyId) {
+	return destroyKey(keyId);
 }
 
 bool Dcenter::destroyConfirmedForgottenKey(uint64 keyId) {
@@ -54,9 +54,6 @@ bool Dcenter::destroyKey(uint64 keyId) {
 	}
 	_key = nullptr;
 	_connectionInited = false;
-	lock.unlock();
-
-	emit authKeyChanged();
 	return true;
 }
 
@@ -86,18 +83,18 @@ void Dcenter::releaseKeyCreationOnFail() {
 	_creatingKey = false;
 }
 
-void Dcenter::releaseKeyCreationOnDone(AuthKeyPtr &&key) {
+void Dcenter::releaseKeyCreationOnDone(const AuthKeyPtr &key) {
 	Expects(_creatingKey);
 	Expects(_key == nullptr);
 
 	QWriteLocker lock(&_mutex);
-	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1), emitting authKeyChanged, dc %2").arg(key ? key->keyId() : 0).arg(_id));
-	_key = std::move(key);
+	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1), "
+		"emitting authKeyChanged, dc %2"
+		).arg(key ? key->keyId() : 0
+		).arg(_id));
+	_key = key;
 	_connectionInited = false;
 	_creatingKey = false;
-	lock.unlock();
-
-	emit authKeyChanged();
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/dcenter.h
index 002762b1c..f935c8619 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/dcenter.h
@@ -16,8 +16,6 @@ using AuthKeyPtr = std::shared_ptr<AuthKey>;
 namespace internal {
 
 class Dcenter : public QObject {
-	Q_OBJECT
-
 public:
 	// Main thread.
 	Dcenter(DcId dcId, AuthKeyPtr &&key);
@@ -26,9 +24,9 @@ public:
 	[[nodiscard]] DcId id() const;
 
 	[[nodiscard]] AuthKeyPtr getKey() const;
-	void destroyCdnKey(uint64 keyId);
+	bool destroyCdnKey(uint64 keyId);
 	bool destroyConfirmedForgottenKey(uint64 keyId);
-	void releaseKeyCreationOnDone(AuthKeyPtr &&key);
+	void releaseKeyCreationOnDone(const AuthKeyPtr &key);
 
 	[[nodiscard]] bool connectionInited() const;
 	void setConnectionInited(bool connectionInited = true);
@@ -36,9 +34,6 @@ public:
 	[[nodiscard]] bool acquireKeyCreation();
 	void releaseKeyCreationOnFail();
 
-signals:
-	void authKeyChanged();
-
 private:
 	bool destroyKey(uint64 keyId);
 
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index c82305c6d..320f1b77c 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -65,7 +65,8 @@ public:
 	void setMainDcId(DcId mainDcId);
 	[[nodiscard]] DcId mainDcId() const;
 
-	void setKeyForWrite(DcId dcId, const AuthKeyPtr &key);
+	void dcKeyChanged(DcId dcId, const AuthKeyPtr &key);
+	[[nodiscard]] rpl::producer<DcId> dcKeyChanged() const;
 	[[nodiscard]] AuthKeysList getKeysForWrite() const;
 	void addKeysForDestroy(AuthKeysList &&keys);
 
@@ -208,6 +209,7 @@ private:
 	bool _mainDcIdForced = false;
 	base::flat_map<DcId, std::unique_ptr<Dcenter>> _dcenters;
 	std::vector<std::unique_ptr<Dcenter>> _dcentersToDestroy;
+	rpl::event_stream<DcId> _dcKeyChanged;
 
 	Session *_mainSession = nullptr;
 	base::flat_map<ShiftedDcId, std::unique_ptr<Session>> _sessions;
@@ -693,7 +695,9 @@ not_null<Dcenter*> Instance::Private::getDcById(
 	return addDc(dcId);
 }
 
-void Instance::Private::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
+void Instance::Private::dcKeyChanged(DcId dcId, const AuthKeyPtr &key) {
+	_dcKeyChanged.fire_copy(dcId);
+
 	if (isTemporaryDcId(dcId)) {
 		return;
 	}
@@ -710,6 +714,10 @@ void Instance::Private::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
 	});
 }
 
+rpl::producer<DcId> Instance::Private::dcKeyChanged() const {
+	return _dcKeyChanged.events();
+}
+
 AuthKeysList Instance::Private::getKeysForWrite() const {
 	auto result = AuthKeysList();
 
@@ -1600,7 +1608,7 @@ void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
 	if (const auto dc = findDc(dcId)) {
 		if (dc->destroyConfirmedForgottenKey(keyId)) {
 			LOG(("Key destroyed!"));
-			setKeyForWrite(dcId, nullptr);
+			dcKeyChanged(dcId, nullptr);
 		} else {
 			LOG(("Key already is different."));
 		}
@@ -1753,10 +1761,12 @@ void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
 	_private->logout(onDone, onFail);
 }
 
-void Instance::setKeyForWrite(DcId dcId, const AuthKeyPtr &key) {
-	InvokeQueued(this, [=] {
-		_private->setKeyForWrite(dcId, key);
-	});
+void Instance::dcKeyChanged(DcId dcId, const AuthKeyPtr &key) {
+	_private->dcKeyChanged(dcId, key);
+}
+
+rpl::producer<DcId> Instance::dcKeyChanged() const {
+	return _private->dcKeyChanged();
 }
 
 AuthKeysList Instance::getKeysForWrite() const {
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 5443745c4..bf4ddc117 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -63,9 +63,10 @@ public:
 	// Thread-safe.
 	[[nodiscard]] QString deviceModel() const;
 	[[nodiscard]] QString systemVersion() const;
-	void setKeyForWrite(DcId dcId, const AuthKeyPtr &key);
 
 	// Main thread.
+	void dcKeyChanged(DcId dcId, const AuthKeyPtr &key);
+	[[nodiscard]] rpl::producer<DcId> dcKeyChanged() const;
 	[[nodiscard]] AuthKeysList getKeysForWrite() const;
 	void addKeysForDestroy(AuthKeysList &&keys);
 
@@ -110,6 +111,8 @@ public:
 	bool isKeysDestroyer() const;
 	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
 	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
+
+	// Main thread.
 	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
 
 	void requestConfig();
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 4ef0ecdd4..99feebb62 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -64,6 +64,19 @@ ConnectionOptions::ConnectionOptions(
 , useTcp(useTcp) {
 }
 
+template <typename Callback>
+void SessionData::withSession(Callback &&callback) {
+	QMutexLocker lock(&_ownerMutex);
+	if (const auto session = _owner) {
+		InvokeQueued(session, [
+			session,
+			callback = std::forward<Callback>(callback)
+		] {
+			callback(session);
+		});
+	}
+}
+
 void SessionData::setCurrentKeyId(uint64 keyId) {
 	QWriteLocker locker(&_lock);
 	if (_keyId == keyId) {
@@ -136,6 +149,115 @@ void SessionData::clearForNewKey(not_null<Instance*> instance) {
 	instance->clearCallbacksDelayed(std::move(clearCallbacks));
 }
 
+void SessionData::queueTryToReceive() {
+	withSession([](not_null<Session*> session) {
+		session->tryToReceive();
+	});
+}
+
+void SessionData::queueNeedToResumeAndSend() {
+	withSession([](not_null<Session*> session) {
+		session->needToResumeAndSend();
+	});
+}
+
+void SessionData::queueConnectionStateChange(int newState) {
+	withSession([=](not_null<Session*> session) {
+		session->connectionStateChange(newState);
+	});
+}
+
+void SessionData::queueResendAll() {
+	withSession([](not_null<Session*> session) {
+		session->resendAll();
+	});
+}
+
+void SessionData::queueResetDone() {
+	withSession([](not_null<Session*> session) {
+		session->resetDone();
+	});
+}
+
+void SessionData::queueSendAnything(crl::time msCanWait) {
+	withSession([=](not_null<Session*> session) {
+		session->sendAnything(msCanWait);
+	});
+}
+
+void SessionData::queueSendMsgsStateInfo(quint64 msgId, QByteArray data) {
+	withSession([=](not_null<Session*> session) {
+		session->sendMsgsStateInfo(msgId, data);
+	});
+}
+
+void SessionData::queueResend(
+		mtpMsgId msgId,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo) {
+	withSession([=](not_null<Session*> session) {
+		session->resend(msgId, msCanWait, forceContainer, sendMsgStateInfo);
+	});
+}
+
+void SessionData::queueResendMany(
+		QVector<mtpMsgId> msgIds,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo) {
+	withSession([=](not_null<Session*> session) {
+		for (const auto msgId : msgIds) {
+			session->resend(
+				msgId,
+				msCanWait,
+				forceContainer,
+				sendMsgStateInfo);
+		}
+	});
+}
+
+bool SessionData::connectionInited() const {
+	QMutexLocker lock(&_ownerMutex);
+	return _owner ? _owner->connectionInited() : false;
+}
+
+AuthKeyPtr SessionData::getKey() const {
+	QMutexLocker lock(&_ownerMutex);
+	return _owner ? _owner->getKey() : nullptr;
+}
+
+bool SessionData::acquireKeyCreation() {
+	QMutexLocker lock(&_ownerMutex);
+	return _owner ? _owner->acquireKeyCreation() : false;
+}
+
+void SessionData::releaseKeyCreationOnDone(const AuthKeyPtr &key) {
+	QMutexLocker lock(&_ownerMutex);
+	if (_owner) {
+		_owner->releaseKeyCreationOnDone(key);
+	}
+}
+
+void SessionData::releaseKeyCreationOnFail() {
+	QMutexLocker lock(&_ownerMutex);
+	if (_owner) {
+		_owner->releaseKeyCreationOnFail();
+	}
+}
+
+void SessionData::destroyCdnKey(uint64 keyId) {
+	QMutexLocker lock(&_ownerMutex);
+	if (_owner) {
+		_owner->destroyCdnKey(keyId);
+	}
+}
+
+void SessionData::detach() {
+	QMutexLocker lock(&_ownerMutex);
+	_owner = nullptr;
+}
+
 Session::Session(
 	not_null<Instance*> instance,
 	ShiftedDcId shiftedDcId,
@@ -145,19 +267,30 @@ Session::Session(
 , _shiftedDcId(shiftedDcId)
 , _ownedDc(dc ? nullptr : std::make_unique<Dcenter>(shiftedDcId, nullptr))
 , _dc(dc ? dc : _ownedDc.get())
-, _data(this)
+, _data(std::make_shared<SessionData>(this))
 , _timeouter([=] { checkRequestsByTimer(); })
 , _sender([=] { needToResumeAndSend(); }) {
 	_timeouter.callEach(1000);
 	refreshOptions();
 	if (sharedDc()) {
-		connect(_dc, SIGNAL(authKeyChanged()), this, SLOT(authKeyChangedForDC()), Qt::QueuedConnection);
+		watchDcKeyChanges();
 	}
 }
 
+void Session::watchDcKeyChanges() {
+	_instance->dcKeyChanged(
+	) | rpl::filter([=](DcId dcId) {
+		return (dcId == _shiftedDcId) || (dcId == BareDcId(_shiftedDcId));
+	}) | rpl::start_with_next([=] {
+		DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, "
+			"emitting authKeyChanged(), dcWithShift %1").arg(_shiftedDcId));
+		emit authKeyChanged();
+	}, _lifetime);
+}
+
 void Session::start() {
 	_connection = std::make_unique<Connection>(_instance);
-	_connection->start(&_data, _shiftedDcId);
+	_connection->start(_data, _shiftedDcId);
 	if (_instance->isKeysDestroyer()) {
 		_instance->scheduleKeyDestroy(_shiftedDcId);
 	}
@@ -189,7 +322,7 @@ void Session::refreshOptions() {
 	const auto useHttp = (proxyType != ProxyData::Type::Mtproto);
 	const auto useIPv4 = true;
 	const auto useIPv6 = Global::TryIPv6();
-	_data.setConnectionOptions(ConnectionOptions(
+	_data->setConnectionOptions(ConnectionOptions(
 		_instance->systemLangCode(),
 		_instance->cloudLangCode(),
 		_instance->langPackName(),
@@ -222,22 +355,25 @@ void Session::stop() {
 void Session::kill() {
 	stop();
 	_killed = true;
+	_data->detach();
 	DEBUG_LOG(("Session Info: marked session dcWithShift %1 as killed").arg(_shiftedDcId));
 }
 
 void Session::unpaused() {
 	if (_needToReceive) {
 		_needToReceive = false;
-		QTimer::singleShot(0, this, SLOT(tryToReceive()));
+		InvokeQueued(this, [=] {
+			tryToReceive();
+		});
 	}
 }
 
 void Session::sendDcKeyCheck(const AuthKeyPtr &key) {
-	_data.setKeyForCheck(key);
+	_data->setKeyForCheck(key);
 	needToResumeAndSend();
 }
 
-void Session::sendAnything(qint64 msCanWait) {
+void Session::sendAnything(crl::time msCanWait) {
 	if (_killed) {
 		DEBUG_LOG(("Session Error: can't send anything in a killed session"));
 		return;
@@ -284,12 +420,6 @@ void Session::needToResumeAndSend() {
 	}
 }
 
-void Session::sendPong(quint64 msgId, quint64 pingId) {
-	_instance->sendProtocolMessage(
-		_shiftedDcId,
-		MTPPong(MTP_pong(MTP_long(msgId), MTP_long(pingId))));
-}
-
 void Session::sendMsgsStateInfo(quint64 msgId, QByteArray data) {
 	auto info = bytes::vector();
 	if (!data.isEmpty()) {
@@ -312,8 +442,8 @@ void Session::checkRequestsByTimer() {
 	QVector<mtpMsgId> stateRequestIds;
 
 	{
-		QReadLocker locker(_data.haveSentMutex());
-		auto &haveSent = _data.haveSentMap();
+		QReadLocker locker(_data->haveSentMutex());
+		auto &haveSent = _data->haveSentMap();
 		const auto haveSentCount = haveSent.size();
 		auto ms = crl::now();
 		for (auto i = haveSent.begin(), e = haveSent.end(); i != e; ++i) {
@@ -340,9 +470,9 @@ void Session::checkRequestsByTimer() {
 	if (stateRequestIds.size()) {
 		DEBUG_LOG(("MTP Info: requesting state of msgs: %1").arg(LogIds(stateRequestIds)));
 		{
-			QWriteLocker locker(_data.stateRequestMutex());
+			QWriteLocker locker(_data->stateRequestMutex());
 			for (uint32 i = 0, l = stateRequestIds.size(); i < l; ++i) {
-				_data.stateRequestMap().insert(stateRequestIds[i], true);
+				_data->stateRequestMap().insert(stateRequestIds[i], true);
 			}
 		}
 		sendAnything(kCheckResendWaiting);
@@ -356,8 +486,8 @@ void Session::checkRequestsByTimer() {
 	if (!removingIds.isEmpty()) {
 		auto clearCallbacks = std::vector<RPCCallbackClear>();
 		{
-			QWriteLocker locker(_data.haveSentMutex());
-			auto &haveSent = _data.haveSentMap();
+			QWriteLocker locker(_data->haveSentMutex());
+			auto &haveSent = _data->haveSentMap();
 			for (uint32 i = 0, l = removingIds.size(); i < l; ++i) {
 				auto j = haveSent.find(removingIds[i]);
 				if (j != haveSent.cend()) {
@@ -372,28 +502,28 @@ void Session::checkRequestsByTimer() {
 	}
 }
 
-void Session::onConnectionStateChange(qint32 newState) {
+void Session::connectionStateChange(int newState) {
 	_instance->onStateChange(_shiftedDcId, newState);
 }
 
-void Session::onResetDone() {
+void Session::resetDone() {
 	_instance->onSessionReset(_shiftedDcId);
 }
 
 void Session::cancel(mtpRequestId requestId, mtpMsgId msgId) {
 	if (requestId) {
-		QWriteLocker locker(_data.toSendMutex());
-		_data.toSendMap().remove(requestId);
+		QWriteLocker locker(_data->toSendMutex());
+		_data->toSendMap().remove(requestId);
 	}
 	if (msgId) {
-		QWriteLocker locker(_data.haveSentMutex());
-		_data.haveSentMap().remove(msgId);
+		QWriteLocker locker(_data->haveSentMutex());
+		_data->haveSentMap().remove(msgId);
 	}
 }
 
 void Session::ping() {
 	_ping = true;
-	sendAnything(0);
+	sendAnything();
 }
 
 int32 Session::requestState(mtpRequestId requestId) const {
@@ -419,8 +549,8 @@ int32 Session::requestState(mtpRequestId requestId) const {
 	}
 	if (!requestId) return MTP::RequestSent;
 
-	QWriteLocker locker(_data.toSendMutex());
-	const auto &toSend = _data.toSendMap();
+	QWriteLocker locker(_data->toSendMutex());
+	const auto &toSend = _data->toSendMap();
 	const auto i = toSend.constFind(requestId);
 	if (i != toSend.cend()) {
 		return MTP::RequestSending;
@@ -456,11 +586,15 @@ QString Session::transport() const {
 	return _connection ? _connection->transport() : QString();
 }
 
-mtpRequestId Session::resend(quint64 msgId, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo) {
+mtpRequestId Session::resend(
+		mtpMsgId msgId,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo) {
 	SecureRequest request;
 	{
-		QWriteLocker locker(_data.haveSentMutex());
-		auto &haveSent = _data.haveSentMap();
+		QWriteLocker locker(_data->haveSentMutex());
+		auto &haveSent = _data->haveSentMap();
 
 		auto i = haveSent.find(msgId);
 		if (i == haveSent.end()) {
@@ -493,8 +627,8 @@ mtpRequestId Session::resend(quint64 msgId, qint64 msCanWait, bool forceContaine
 		request->msDate = forceContainer ? 0 : crl::now();
 		sendPrepared(request, msCanWait, false);
 		{
-			QWriteLocker locker(_data.toResendMutex());
-			_data.toResendMap().insert(msgId, request->requestId);
+			QWriteLocker locker(_data->toResendMutex());
+			_data->toResendMap().insert(msgId, request->requestId);
 		}
 		return request->requestId;
 	} else {
@@ -502,17 +636,11 @@ mtpRequestId Session::resend(quint64 msgId, qint64 msCanWait, bool forceContaine
 	}
 }
 
-void Session::resendMany(QVector<quint64> msgIds, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo) {
-	for (int32 i = 0, l = msgIds.size(); i < l; ++i) {
-		resend(msgIds.at(i), msCanWait, forceContainer, sendMsgStateInfo);
-	}
-}
-
 void Session::resendAll() {
 	QVector<mtpMsgId> toResend;
 	{
-		QReadLocker locker(_data.haveSentMutex());
-		const auto &haveSent = _data.haveSentMap();
+		QReadLocker locker(_data->haveSentMutex());
+		const auto &haveSent = _data->haveSentMap();
 		toResend.reserve(haveSent.size());
 		for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
 			if (i.value()->requestId) {
@@ -532,8 +660,8 @@ void Session::sendPrepared(
 	DEBUG_LOG(("MTP Info: adding request to toSendMap, msCanWait %1"
 		).arg(msCanWait));
 	{
-		QWriteLocker locker(_data.toSendMutex());
-		_data.toSendMap().insert(request->requestId, request);
+		QWriteLocker locker(_data->toSendMutex());
+		_data->toSendMap().insert(request->requestId, request);
 
 		if (newRequest) {
 			*(mtpMsgId*)(request->data() + 4) = 0;
@@ -546,29 +674,37 @@ void Session::sendPrepared(
 	sendAnything(msCanWait);
 }
 
-void Session::authKeyChangedForDC() {
-	DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, emitting authKeyChanged(), dcWithShift %1").arg(_shiftedDcId));
-	emit authKeyChanged();
-}
-
 bool Session::acquireKeyCreation() {
-	return _dc->acquireKeyCreation();
+	Expects(!_myKeyCreation);
+
+	if (!_dc->acquireKeyCreation()) {
+		return false;
+	}
+	_myKeyCreation = true;
+	return true;
 }
 
 void Session::releaseKeyCreationOnFail() {
+	Expects(_myKeyCreation);
+
 	_dc->releaseKeyCreationOnFail();
+	_myKeyCreation = false;
 }
 
-void Session::releaseKeyCreationOnDone(AuthKeyPtr &&key) {
+void Session::releaseKeyCreationOnDone(const AuthKeyPtr &key) {
+	Expects(_myKeyCreation);
+
 	DEBUG_LOG(("AuthKey Info: Session key created, setting, dcWithShift %1").arg(_shiftedDcId));
+	_dc->releaseKeyCreationOnDone(key);
+	_myKeyCreation = false;
+
 	if (sharedDc()) {
 		const auto dcId = _dc->id();
 		const auto instance = _instance;
 		InvokeQueued(instance, [=] {
-			instance->setKeyForWrite(dcId, key);
+			instance->dcKeyChanged(dcId, key);
 		});
 	}
-	_dc->releaseKeyCreationOnDone(std::move(key));
 }
 
 void Session::notifyDcConnectionInited() {
@@ -577,12 +713,14 @@ void Session::notifyDcConnectionInited() {
 }
 
 void Session::destroyCdnKey(uint64 keyId) {
-	_dc->destroyCdnKey(keyId);
+	if (!_dc->destroyCdnKey(keyId)) {
+		return;
+	}
 	if (sharedDc()) {
 		const auto dcId = _dc->id();
 		const auto instance = _instance;
 		InvokeQueued(instance, [=] {
-			instance->setKeyForWrite(dcId, nullptr);
+			instance->dcKeyChanged(dcId, nullptr);
 		});
 	}
 }
@@ -613,11 +751,11 @@ void Session::tryToReceive() {
 		auto isUpdate = false;
 		auto message = SerializedMessage();
 		{
-			QWriteLocker locker(_data.haveReceivedMutex());
-			auto &responses = _data.haveReceivedResponses();
+			QWriteLocker locker(_data->haveReceivedMutex());
+			auto &responses = _data->haveReceivedResponses();
 			auto response = responses.begin();
 			if (response == responses.cend()) {
-				auto &updates = _data.haveReceivedUpdates();
+				auto &updates = _data->haveReceivedUpdates();
 				auto update = updates.begin();
 				if (update == updates.cend()) {
 					return;
@@ -643,6 +781,9 @@ void Session::tryToReceive() {
 }
 
 Session::~Session() {
+	if (_myKeyCreation) {
+		releaseKeyCreationOnFail();
+	}
 	Assert(_connection == nullptr);
 }
 
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index cc5a03d6d..a0075a214 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -249,10 +249,8 @@ public:
 		return _stateRequest;
 	}
 
-	not_null<Session*> owner() {
-		return _owner;
-	}
-	not_null<const Session*> owner() const {
+	// Warning! Valid only in constructor, _owner is guaranteed != null.
+	[[nodiscard]] not_null<Session*> owner() {
 		return _owner;
 	}
 
@@ -265,13 +263,45 @@ public:
 
 	void clearForNewKey(not_null<Instance*> instance);
 
+	// Connection -> Session interface.
+	void queueTryToReceive();
+	void queueNeedToResumeAndSend();
+	void queueConnectionStateChange(int newState);
+	void queueResendAll();
+	void queueResetDone();
+	void queueSendAnything(crl::time msCanWait = 0);
+	void queueSendMsgsStateInfo(quint64 msgId, QByteArray data);
+	void queueResend(
+		mtpMsgId msgId,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo);
+	void queueResendMany(
+		QVector<mtpMsgId> msgIds,
+		crl::time msCanWait,
+		bool forceContainer,
+		bool sendMsgStateInfo);
+
+	[[nodiscard]] bool connectionInited() const;
+	[[nodiscard]] AuthKeyPtr getKey() const;
+	[[nodiscard]] bool acquireKeyCreation();
+	void releaseKeyCreationOnDone(const AuthKeyPtr &key);
+	void releaseKeyCreationOnFail();
+	void destroyCdnKey(uint64 keyId);
+
+	void detach();
+
 private:
+	template <typename Callback>
+	void withSession(Callback &&callback);
+
 	uint64 _keyId = 0;
 	uint64 _sessionId = 0;
 	uint64 _salt = 0;
 	uint32 _messagesSent = 0;
 
-	not_null<Session*> _owner;
+	Session *_owner = nullptr;
+	mutable QMutex _ownerMutex;
 
 	AuthKeyPtr _dcKeyForCheck;
 	ConnectionOptions _options;
@@ -327,7 +357,7 @@ public:
 	// Connection thread.
 	[[nodiscard]] bool acquireKeyCreation();
 	void releaseKeyCreationOnFail();
-	void releaseKeyCreationOnDone(AuthKeyPtr &&key);
+	void releaseKeyCreationOnDone(const AuthKeyPtr &key);
 	void destroyCdnKey(uint64 keyId);
 
 	void notifyDcConnectionInited();
@@ -346,32 +376,29 @@ public:
 		crl::time msCanWait = 0,
 		bool newRequest = true);
 
+	void tryToReceive();
+	void needToResumeAndSend();
+	void connectionStateChange(int newState);
+	void resendAll(); // After connection restart.
+	void resetDone();
+	void sendAnything(crl::time msCanWait = 0);
+	void sendMsgsStateInfo(quint64 msgId, QByteArray data);
+	mtpRequestId resend(
+		mtpMsgId msgId,
+		crl::time msCanWait = 0,
+		bool forceContainer = false,
+		bool sendMsgStateInfo = false);
+
 signals:
 	void authKeyChanged();
 	void needToSend();
 	void needToPing();
 	void needToRestart();
 
-public slots:
-	void needToResumeAndSend();
-
-	mtpRequestId resend(quint64 msgId, qint64 msCanWait = 0, bool forceContainer = false, bool sendMsgStateInfo = false);
-	void resendMany(QVector<quint64> msgIds, qint64 msCanWait, bool forceContainer, bool sendMsgStateInfo);
-	void resendAll(); // after connection restart
-
-	void authKeyChangedForDC();
-
-	void tryToReceive();
-	void onConnectionStateChange(qint32 newState);
-	void onResetDone();
-
-	void sendAnything(qint64 msCanWait = 0);
-	void sendPong(quint64 msgId, quint64 pingId);
-	void sendMsgsStateInfo(quint64 msgId, QByteArray data);
-
 private:
 	[[nodiscard]] bool sharedDc() const;
 	void checkRequestsByTimer();
+	void watchDcKeyChanges();
 
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
 
@@ -379,15 +406,15 @@ private:
 	const ShiftedDcId _shiftedDcId = 0;
 	const std::unique_ptr<Dcenter> _ownedDc;
 	const not_null<Dcenter*> _dc;
+	const std::shared_ptr<SessionData> _data;
 
 	std::unique_ptr<Connection> _connection;
 
 	bool _killed = false;
 	bool _needToReceive = false;
 
-	SessionData _data;
-
 	AuthKeyPtr _dcKeyForCheck;
+	bool _myKeyCreation = false;
 
 	crl::time _msSendCall = 0;
 	crl::time _msWait = 0;
@@ -397,6 +424,8 @@ private:
 	base::Timer _timeouter;
 	base::Timer _sender;
 
+	rpl::lifetime _lifetime;
+
 };
 
 } // namespace internal

From 173ae746a296a1815e79614e6179255f00379c5d Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 19 Nov 2019 13:10:51 +0300
Subject: [PATCH 30/91] First version of working through temp keys.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 258 +++---
 Telegram/SourceFiles/mtproto/connection.h     |  12 +-
 Telegram/SourceFiles/mtproto/dcenter.cpp      |  54 +-
 Telegram/SourceFiles/mtproto/dcenter.h        |  14 +-
 ..._checker.cpp => mtproto_dc_key_binder.cpp} |  85 +-
 ..._key_checker.h => mtproto_dc_key_binder.h} |  26 +-
 .../details/mtproto_dc_key_creator.cpp        | 774 +++++++++---------
 .../mtproto/details/mtproto_dc_key_creator.h  |  75 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 137 ++--
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   5 +-
 .../SourceFiles/mtproto/mtproto_auth_key.cpp  |  10 +
 .../SourceFiles/mtproto/mtproto_auth_key.h    |   4 +
 Telegram/SourceFiles/mtproto/session.cpp      |  75 +-
 Telegram/SourceFiles/mtproto/session.h        |  18 +-
 Telegram/gyp/lib_mtproto.gyp                  |   4 +-
 15 files changed, 883 insertions(+), 668 deletions(-)
 rename Telegram/SourceFiles/mtproto/details/{mtproto_dc_key_checker.cpp => mtproto_dc_key_binder.cpp} (67%)
 rename Telegram/SourceFiles/mtproto/details/{mtproto_dc_key_checker.h => mtproto_dc_key_binder.h} (58%)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 1ab49e795..64a766075 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -7,8 +7,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/connection.h"
 
+#include "mtproto/details/mtproto_dc_key_binder.h"
 #include "mtproto/details/mtproto_dc_key_creator.h"
-#include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/details/mtproto_dump_to_text.h"
 #include "mtproto/session.h"
 #include "mtproto/mtproto_rsa_public_key.h"
@@ -23,10 +23,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/qthelp_url.h"
 #include "base/unixtime.h"
 
-#ifdef small
-#undef small
-#endif // small
-
 namespace MTP {
 namespace internal {
 namespace {
@@ -42,6 +38,7 @@ constexpr auto kPingDelayDisconnect = 60;
 constexpr auto kPingSendAfter = 30 * crl::time(1000);
 constexpr auto kPingSendAfterForce = 45 * crl::time(1000);
 constexpr auto kCheckKeyExpiresIn = TimeId(3600);
+constexpr auto kTemporaryExpiresIn = TimeId(10);
 constexpr auto kTestModeDcIdShift = 10000;
 
 // If we can't connect for this time we will ask _instance to update config.
@@ -248,6 +245,7 @@ ConnectionPrivate::ConnectionPrivate(
 
 ConnectionPrivate::~ConnectionPrivate() {
 	clearKeyCreatorOnFail();
+	cancelKeyBinder();
 
 	Expects(_finished);
 	Expects(!_connection);
@@ -548,12 +546,20 @@ void ConnectionPrivate::tryToSend() {
 		return;
 	}
 
-	auto needsLayer = !_sessionData->connectionInited();
-	auto state = getState();
-	auto sendOnlyFirstPing = (state != ConnectedState);
+	const auto needsLayer = !_sessionData->connectionInited();
+	const auto state = getState();
+	const auto sendOnlyFirstPing = (state != ConnectedState);
+	const auto sendAll = !sendOnlyFirstPing && !_keyBinder;
+	const auto isMainSession = (GetDcIdShift(_shiftedDcId) == 0);
 	if (sendOnlyFirstPing && !_pingIdToSend) {
 		DEBUG_LOG(("MTP Info: dc %1 not sending, waiting for Connected state, state: %2").arg(_shiftedDcId).arg(state));
 		return; // just do nothing, if is not connected yet
+	} else if (isMainSession
+		&& !sendOnlyFirstPing
+		&& !_pingIdToSend
+		&& !_pingId
+		&& _pingSendAt <= crl::now()) {
+		_pingIdToSend = openssl::RandomValue<mtpPingId>();
 	}
 
 	auto pingRequest = SecureRequest();
@@ -561,34 +567,31 @@ void ConnectionPrivate::tryToSend() {
 	auto resendRequest = SecureRequest();
 	auto stateRequest = SecureRequest();
 	auto httpWaitRequest = SecureRequest();
-	auto checkDcKeyRequest = SecureRequest();
-	if (_shiftedDcId == BareDcId(_shiftedDcId)) { // main session
-		if (!sendOnlyFirstPing && !_pingIdToSend && !_pingId && _pingSendAt <= crl::now()) {
-			_pingIdToSend = rand_value<mtpPingId>();
-		}
-	}
+	auto bindDcKeyRequest = SecureRequest();
 	if (_pingIdToSend) {
-		if (sendOnlyFirstPing || _shiftedDcId != BareDcId(_shiftedDcId)) {
+		if (sendOnlyFirstPing || !isMainSession) {
+			DEBUG_LOG(("MTP Info: sending ping, ping_id: %1"
+				).arg(_pingIdToSend));
 			pingRequest = SecureRequest::Serialize(MTPPing(
 				MTP_long(_pingIdToSend)
 			));
-			DEBUG_LOG(("MTP Info: sending ping, ping_id: %1"
-				).arg(_pingIdToSend));
 		} else {
+			DEBUG_LOG(("MTP Info: sending ping_delay_disconnect, "
+				"ping_id: %1").arg(_pingIdToSend));
 			pingRequest = SecureRequest::Serialize(MTPPing_delay_disconnect(
 				MTP_long(_pingIdToSend),
 				MTP_int(kPingDelayDisconnect)));
-			DEBUG_LOG(("MTP Info: sending ping_delay_disconnect, "
-				"ping_id: %1").arg(_pingIdToSend));
-		}
-
-		_pingSendAt = pingRequest->msDate + kPingSendAfter;
-		if (_shiftedDcId == BareDcId(_shiftedDcId) && !sendOnlyFirstPing) { // main session
 			_pingSender.callOnce(kPingSendAfterForce);
 		}
+		_pingSendAt = pingRequest->msDate + kPingSendAfter;
 		_pingId = base::take(_pingIdToSend);
+	} else if (!sendAll) {
+		DEBUG_LOG(("MTP Info: dc %1 sending only service or bind."
+			).arg(_shiftedDcId));
 	} else {
-		DEBUG_LOG(("MTP Info: dc %1 trying to send after ping, state: %2").arg(_shiftedDcId).arg(state));
+		DEBUG_LOG(("MTP Info: dc %1 trying to send after ping, state: %2"
+			).arg(_shiftedDcId
+			).arg(state));
 	}
 
 	if (!sendOnlyFirstPing) {
@@ -625,23 +628,34 @@ void ConnectionPrivate::tryToSend() {
 			httpWaitRequest = SecureRequest::Serialize(MTPHttpWait(
 				MTP_http_wait(MTP_int(100), MTP_int(30), MTP_int(25000))));
 		}
-		if (!_keyChecker) {
-			if (const auto &keyForCheck = _sessionData->getKeyForCheck()) {
-				_keyChecker = std::make_unique<details::DcKeyChecker>(
-					_instance,
-					_shiftedDcId,
-					keyForCheck);
-				checkDcKeyRequest = _keyChecker->prepareRequest(
-					_key,
-					_sessionData->getSessionId());
+		if (_keyBinder && !_keyBinder->requested()) {
+			bindDcKeyRequest = _keyBinder->prepareRequest(
+				_temporaryKey,
+				_sessionData->getSessionId());
 
-				// This is a special request with msgId used inside the message
-				// body, so it is prepared already with a msgId and we place
-				// seqNo for it manually here.
-				checkDcKeyRequest.setSeqNo(
-					_sessionData->nextRequestSeqNumber(
-						checkDcKeyRequest.needAck()));
-			}
+			// This is a special request with msgId used inside the message
+			// body, so it is prepared already with a msgId and we place
+			// seqNo for it manually here.
+			bindDcKeyRequest.setSeqNo(
+				_sessionData->nextRequestSeqNumber(
+					bindDcKeyRequest.needAck()));
+		//} else if (!_keyChecker) {
+		//	if (const auto &keyForCheck = _sessionData->getKeyForCheck()) {
+		//		_keyChecker = std::make_unique<details::DcKeyChecker>(
+		//			_instance,
+		//			_shiftedDcId,
+		//			keyForCheck);
+		//		bindDcKeyRequest = _keyChecker->prepareRequest(
+		//			_temporaryKey,
+		//			_sessionData->getSessionId());
+
+		//		// This is a special request with msgId used inside the message
+		//		// body, so it is prepared already with a msgId and we place
+		//		// seqNo for it manually here.
+		//		bindDcKeyRequest.setSeqNo(
+		//			_sessionData->nextRequestSeqNumber(
+		//				bindDcKeyRequest.needAck()));
+		//	}
 		}
 	}
 
@@ -696,11 +710,14 @@ void ConnectionPrivate::tryToSend() {
 		QWriteLocker locker1(_sessionData->toSendMutex());
 
 		auto toSendDummy = PreRequestMap();
-		auto &toSend = sendOnlyFirstPing
-			? toSendDummy
-			: _sessionData->toSendMap();
-		if (sendOnlyFirstPing) {
+		auto &toSend = sendAll
+			? _sessionData->toSendMap()
+			: toSendDummy;
+		if (!sendAll) {
 			locker1.unlock();
+		} else {
+			int time = crl::now();
+			int now = crl::now();
 		}
 
 		uint32 toSendCount = toSend.size();
@@ -709,7 +726,7 @@ void ConnectionPrivate::tryToSend() {
 		if (resendRequest) ++toSendCount;
 		if (stateRequest) ++toSendCount;
 		if (httpWaitRequest) ++toSendCount;
-		if (checkDcKeyRequest) ++toSendCount;
+		if (bindDcKeyRequest) ++toSendCount;
 
 		if (!toSendCount) {
 			return; // nothing to send
@@ -725,12 +742,12 @@ void ConnectionPrivate::tryToSend() {
 			? stateRequest
 			: httpWaitRequest
 			? httpWaitRequest
-			: checkDcKeyRequest
-			? checkDcKeyRequest
+			: bindDcKeyRequest
+			? bindDcKeyRequest
 			: toSend.cbegin().value();
 		if (toSendCount == 1 && first->msDate > 0) { // if can send without container
 			toSendRequest = first;
-			if (!sendOnlyFirstPing) {
+			if (sendAll) {
 				toSend.clear();
 				locker1.unlock();
 			}
@@ -753,9 +770,7 @@ void ConnectionPrivate::tryToSend() {
 					auto &haveSent = _sessionData->haveSentMap();
 					haveSent.insert(msgId, toSendRequest);
 
-					if (needsLayer && !toSendRequest->needsLayer) {
-						needsLayer = false;
-					}
+					const auto wrapLayer = needsLayer && toSendRequest->needsLayer;
 					if (toSendRequest->after) {
 						const auto toSendSize = tl::count_length(toSendRequest) >> 2;
 						auto wrappedRequest = SecureRequest::Prepare(
@@ -766,7 +781,7 @@ void ConnectionPrivate::tryToSend() {
 						wrapInvokeAfter(wrappedRequest, toSendRequest, haveSent);
 						toSendRequest = std::move(wrappedRequest);
 					}
-					if (needsLayer) {
+					if (wrapLayer) {
 						const auto noWrapSize = (tl::count_length(toSendRequest) >> 2);
 						const auto toSendSize = noWrapSize + initSizeInInts;
 						auto wrappedRequest = SecureRequest::Prepare(toSendSize);
@@ -793,7 +808,7 @@ void ConnectionPrivate::tryToSend() {
 			if (resendRequest) containerSize += resendRequest.messageSize();
 			if (stateRequest) containerSize += stateRequest.messageSize();
 			if (httpWaitRequest) containerSize += httpWaitRequest.messageSize();
-			if (checkDcKeyRequest) containerSize += checkDcKeyRequest.messageSize();
+			if (bindDcKeyRequest) containerSize += bindDcKeyRequest.messageSize();
 			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
 				containerSize += i.value().messageSize();
 				if (needsLayer && i.value()->needsLayer) {
@@ -836,7 +851,7 @@ void ConnectionPrivate::tryToSend() {
 			if (pingRequest) {
 				_pingMsgId = placeToContainer(toSendRequest, bigMsgId, haveSentArr, pingRequest);
 				needAnyResponse = true;
-			} else if (resendRequest || stateRequest || checkDcKeyRequest) {
+			} else if (resendRequest || stateRequest || bindDcKeyRequest) {
 				needAnyResponse = true;
 			}
 			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
@@ -890,7 +905,7 @@ void ConnectionPrivate::tryToSend() {
 			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, resendRequest);
 			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, ackRequest);
 			if (httpWaitRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, httpWaitRequest);
-			if (checkDcKeyRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, checkDcKeyRequest);
+			if (bindDcKeyRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, bindDcKeyRequest);
 
 			mtpMsgId contMsgId = prepareToSend(toSendRequest, bigMsgId);
 			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = contMsgId;
@@ -930,7 +945,7 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 		_sessionData->connectionOptions());
 
 	// #TODO race.
-	const auto hasKey = (_sessionData->getKey() != nullptr);
+	const auto hasKey = (_sessionData->getTemporaryKey() != nullptr);
 
 	const auto bareDc = BareDcId(_shiftedDcId);
 	_dcType = _instance->dcOptions()->dcType(_shiftedDcId);
@@ -1236,9 +1251,9 @@ void ConnectionPrivate::handleReceived() {
 		auto msgKey = *(MTPint128*)(ints + 2);
 
 #ifdef TDESKTOP_MTPROTO_OLD
-		aesIgeDecrypt_oldmtp(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _key, msgKey);
+		aesIgeDecrypt_oldmtp(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _temporaryKey, msgKey);
 #else // TDESKTOP_MTPROTO_OLD
-		aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _key, msgKey);
+		aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _temporaryKey, msgKey);
 #endif // TDESKTOP_MTPROTO_OLD
 
 		auto decryptedInts = reinterpret_cast<const mtpPrime*>(decryptedBuffer.constData());
@@ -1285,7 +1300,7 @@ void ConnectionPrivate::handleReceived() {
 
 		SHA256_CTX msgKeyLargeContext;
 		SHA256_Init(&msgKeyLargeContext);
-		SHA256_Update(&msgKeyLargeContext, _key->partForMsgKey(false), 32);
+		SHA256_Update(&msgKeyLargeContext, _temporaryKey->partForMsgKey(false), 32);
 		SHA256_Update(&msgKeyLargeContext, decryptedInts, encryptedBytesCount);
 		SHA256_Final(sha256Buffer.data(), &msgKeyLargeContext);
 
@@ -1386,7 +1401,9 @@ void ConnectionPrivate::handleReceived() {
 
 		if (res != HandleResult::Success && res != HandleResult::Ignored) {
 			_needSessionReset = (res == HandleResult::ResetSession);
-
+			if (res == HandleResult::DestroyTemporaryKey) {
+				destroyTemporaryKey();
+			}
 			return restart();
 		}
 		_retryTimeout = 1; // reset restart() timer
@@ -1884,15 +1901,37 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			response.resize(end - from);
 			memcpy(response.data(), from, (end - from) * sizeof(mtpPrime));
 		}
-		if (typeId != mtpc_rpc_error) {
+		if (typeId == mtpc_rpc_error) {
+			if (DcKeyBinder::IsDestroyedTemporaryKeyError(response)) {
+				return HandleResult::DestroyTemporaryKey;
+			}
+		} else {
 			// An error could be some RPC_CALL_FAIL or other error inside
 			// the initConnection, so we're not sure yet that it was inited.
 			// Wait till a good response is received.
 			_sessionData->notifyConnectionInited(*_connectionOptions);
 		}
 
-		if (_keyChecker && _keyChecker->handleResponse(reqMsgId, response)) {
-			return HandleResult::Success;
+		if (_keyBinder) {
+			const auto result = _keyBinder->handleResponse(
+				reqMsgId,
+				response);
+			if (result == DcKeyBindState::Success) {
+				_sessionData->releaseKeyCreationOnDone(
+					_temporaryKey,
+					base::take(_keyBinder)->persistentKey());
+				_sessionData->queueNeedToResumeAndSend();
+				return HandleResult::Success;
+			} else if (result == DcKeyBindState::Failed
+				|| result == DcKeyBindState::DefinitelyDestroyed) {
+				// #TODO maybe destroy persistent key
+				// crl::on_main(
+				//   _keyBinder->persistentKey()->setLastCheckTime(crl::now());
+				//   instance->keyDestroyedOnServer(BareDcId(shiftedDcId), base::take(_keyBinder)->persistentKey()->keyId());
+				// )
+				_sessionData->queueNeedToResumeAndSend();
+				return HandleResult::Success;
+			}
 		}
 		auto requestId = wasSent(reqMsgId.v);
 		if (requestId && requestId != mtpRequestId(0xFFFFFFFF)) {
@@ -2341,17 +2380,17 @@ void ConnectionPrivate::checkAuthKey() {
 }
 
 void ConnectionPrivate::updateAuthKey() {
-	if (_keyCreator) {
+	if (_keyCreator || _keyBinder) {
 		return;
 	}
 
 	DEBUG_LOG(("AuthKey Info: Connection updating key from Session, dc %1").arg(_shiftedDcId));
-	applyAuthKey(_sessionData->getKey());
+	applyAuthKey(_sessionData->getTemporaryKey());
 }
 
-void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&key) {
-	_key = std::move(key);
-	const auto newKeyId = _key ? _key->keyId() : 0;
+void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
+	_temporaryKey = std::move(temporaryKey);
+	const auto newKeyId = _temporaryKey ? _temporaryKey->keyId() : 0;
 	if (newKeyId) {
 		if (_keyId == newKeyId) {
 			return;
@@ -2389,19 +2428,39 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&key) {
 }
 
 void ConnectionPrivate::createDcKey() {
+	Expects(_keyCreator == nullptr);
+	Expects(_keyBinder == nullptr);
+
 	using Result = DcKeyCreator::Result;
 	using Error = DcKeyCreator::Error;
 	auto delegate = DcKeyCreator::Delegate();
 	delegate.done = [=](base::expected<Result, Error> result) {
 		if (result) {
-			DEBUG_LOG(("AuthKey Info: auth key gen succeed, id: %1, server salt: %2").arg(result->key->keyId()).arg(result->serverSalt));
+			DEBUG_LOG(("AuthKey Info: auth key gen succeed, "
+				"ids: (%1, %2) server salts: (%3, %4)"
+				).arg(result->temporaryKey
+					? result->temporaryKey->keyId()
+					: 0
+				).arg(result->persistentKey
+					? result->persistentKey->keyId()
+					: 0
+				).arg(result->temporaryServerSalt
+				).arg(result->persistentServerSalt));
 
-			_sessionData->setSalt(result->serverSalt);
+			_sessionData->setSalt(result->temporaryServerSalt);
 			_sessionData->clearForNewKey(_instance);
 
+			auto key = result->persistentKey
+				? std::move(result->persistentKey)
+				: _sessionData->getPersistentKey();
+			if (!key) {
+				restart();
+			}
 			_keyCreator = nullptr;
-			_sessionData->releaseKeyCreationOnDone(result->key);
-			applyAuthKey(std::move(result->key));
+			_keyBinder = std::make_unique<DcKeyBinder>(std::move(key));
+			result->temporaryKey->setExpiresAt(
+				base::unixtime::now() + kTemporaryExpiresIn);
+			applyAuthKey(std::move(result->temporaryKey));
 			return;
 		}
 		clearKeyCreatorOnFail();
@@ -2417,16 +2476,23 @@ void ConnectionPrivate::createDcKey() {
 			restart();
 		}
 	};
-	const auto expireIn = (GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift)
-		? kCheckKeyExpiresIn
-		: TimeId(0);
+	delegate.sentSome = [=](uint64 size) {
+		onSentSome(size);
+	};
+	delegate.receivedSome = [=] {
+		onReceivedSome();
+	};
+//	const auto check = (GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift); // #TODO remove kCheckKeyDcShift
+	auto request = DcKeyCreator::Request();
+	request.persistentNeeded = !_sessionData->getPersistentKey();
+	request.temporaryExpiresIn = kTemporaryExpiresIn;
 	_keyCreator = std::make_unique<DcKeyCreator>(
 		BareDcId(_shiftedDcId),
 		getProtocolDcId(),
 		_connection.get(),
 		_instance->dcOptions(),
 		std::move(delegate),
-		expireIn);
+		request);
 }
 
 void ConnectionPrivate::authKeyChecked() {
@@ -2471,28 +2537,26 @@ void ConnectionPrivate::handleError(int errorCode) {
 	_waitForConnectedTimer.cancel();
 
 	if (errorCode == -404) {
-		if (_dcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
-			LOG(("MTP Info: -404 error received in CDN dc %1, assuming it was destroyed, recreating.").arg(_shiftedDcId));
-			destroyCdnKey();
-			return restart();
-		} else {
-			LOG(("MTP Info: -404 error received, informing instance."));
+		if (_instance->isKeysDestroyer()) {
+			LOG(("MTP Info: -404 error received in destroyer %1, assuming key was destroyed.").arg(_shiftedDcId));
 			_instance->checkIfKeyWasDestroyed(_shiftedDcId);
-			if (_instance->isKeysDestroyer()) {
-				return;
-			}
+			return;
+		} else if (_temporaryKey) {
+			LOG(("MTP Info: -404 error received in %1 with temporary key, assuming it was destroyed.").arg(_shiftedDcId));
+			destroyTemporaryKey();
 		}
 	}
 	MTP_LOG(_shiftedDcId, ("Restarting after error in connection, error code: %1...").arg(errorCode));
 	return restart();
 }
 
-void ConnectionPrivate::destroyCdnKey() {
-	if (_key) {
-		_sessionData->destroyCdnKey(_keyId);
+void ConnectionPrivate::destroyTemporaryKey() {
+	cancelKeyBinder();
+	if (_temporaryKey) {
+		_sessionData->destroyTemporaryKey(_temporaryKey->keyId());
 	}
-	_key = nullptr;
-	_keyId = 0;
+	_needSessionReset = true;
+	applyAuthKey(nullptr);
 }
 
 bool ConnectionPrivate::sendSecureRequest(
@@ -2542,7 +2606,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		request->constData(),
 		&packet[prefix],
 		fullSize * sizeof(mtpPrime),
-		_key,
+		_temporaryKey,
 		msgKey);
 #else // TDESKTOP_MTPROTO_OLD
 	uchar encryptedSHA256[32];
@@ -2550,7 +2614,7 @@ bool ConnectionPrivate::sendSecureRequest(
 
 	SHA256_CTX msgKeyLargeContext;
 	SHA256_Init(&msgKeyLargeContext);
-	SHA256_Update(&msgKeyLargeContext, _key->partForMsgKey(true), 32);
+	SHA256_Update(&msgKeyLargeContext, _temporaryKey->partForMsgKey(true), 32);
 	SHA256_Update(&msgKeyLargeContext, request->constData(), fullSize * sizeof(mtpPrime));
 	SHA256_Final(encryptedSHA256, &msgKeyLargeContext);
 
@@ -2562,7 +2626,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		request->constData(),
 		&packet[prefix],
 		fullSize * sizeof(mtpPrime),
-		_key,
+		_temporaryKey,
 		msgKey);
 #endif // TDESKTOP_MTPROTO_OLD
 
@@ -2613,6 +2677,14 @@ void ConnectionPrivate::clearKeyCreatorOnFail() {
 	_sessionData->releaseKeyCreationOnFail();
 }
 
+void ConnectionPrivate::cancelKeyBinder() {
+	if (!_keyBinder) {
+		return;
+	}
+	_keyBinder = nullptr;
+	_sessionData->releaseKeyCreationOnFail();
+}
+
 void ConnectionPrivate::stop() {
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 78c2217a8..ed6950adf 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -17,7 +17,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace MTP {
 namespace details {
 class DcKeyCreator;
-class DcKeyChecker;
+class DcKeyBinder;
 } // namespace details
 
 // How much time to wait for some more requests, when sending msg acks.
@@ -103,6 +103,7 @@ private:
 		Ignored,
 		RestartConnection,
 		ResetSession,
+		DestroyTemporaryKey,
 		ParseError,
 	};
 
@@ -180,9 +181,10 @@ private:
 	void resetSession();
 	void checkAuthKey();
 	void authKeyChecked();
-	void destroyCdnKey();
+	void destroyTemporaryKey();
 	void clearKeyCreatorOnFail();
-	void applyAuthKey(AuthKeyPtr &&key);
+	void cancelKeyBinder();
+	void applyAuthKey(AuthKeyPtr &&temporaryKey);
 
 	const not_null<Instance*> _instance;
 	DcType _dcType = DcType::Regular;
@@ -224,13 +226,13 @@ private:
 	bool _restarted = false;
 	bool _finished = false;
 
-	AuthKeyPtr _key;
+	AuthKeyPtr _temporaryKey;
 	uint64 _keyId = 0;
 	std::shared_ptr<SessionData> _sessionData;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 
 	std::unique_ptr<details::DcKeyCreator> _keyCreator;
-	std::unique_ptr<details::DcKeyChecker> _keyChecker;
+	std::unique_ptr<details::DcKeyBinder> _keyBinder;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/dcenter.cpp
index fa2f10d8a..22e212698 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/dcenter.cpp
@@ -25,34 +25,40 @@ constexpr auto kSpecialRequestTimeoutMs = 6000; // 4 seconds timeout for it to w
 
 Dcenter::Dcenter(DcId dcId, AuthKeyPtr &&key)
 : _id(dcId)
-, _key(std::move(key)) {
+, _persistentKey(std::move(key)) {
 }
 
 DcId Dcenter::id() const {
 	return _id;
 }
 
-AuthKeyPtr Dcenter::getKey() const {
+AuthKeyPtr Dcenter::getTemporaryKey() const {
 	QReadLocker lock(&_mutex);
-	return _key;
+	return _temporaryKey;
 }
 
-bool Dcenter::destroyCdnKey(uint64 keyId) {
-	return destroyKey(keyId);
+AuthKeyPtr Dcenter::getPersistentKey() const {
+	QReadLocker lock(&_mutex);
+	return _persistentKey;
+}
+
+bool Dcenter::destroyTemporaryKey(uint64 keyId) {
+	QWriteLocker lock(&_mutex);
+	if (!_temporaryKey || _temporaryKey->keyId() != keyId) {
+		return false;
+	}
+	_temporaryKey = nullptr;
+	_connectionInited = false;
+	return true;
 }
 
 bool Dcenter::destroyConfirmedForgottenKey(uint64 keyId) {
-	return destroyKey(keyId);
-}
-
-bool Dcenter::destroyKey(uint64 keyId) {
-	Expects(!_creatingKey || !_key);
-
 	QWriteLocker lock(&_mutex);
-	if (_key->keyId() != keyId) {
+	if (!_persistentKey || _persistentKey->keyId() != keyId) {
 		return false;
 	}
-	_key = nullptr;
+	_temporaryKey = nullptr;
+	_persistentKey = nullptr;
 	_connectionInited = false;
 	return true;
 }
@@ -69,7 +75,7 @@ void Dcenter::setConnectionInited(bool connectionInited) {
 
 bool Dcenter::acquireKeyCreation() {
 	QReadLocker lock(&_mutex);
-	if (_key != nullptr) {
+	if (_temporaryKey != nullptr) {
 		return false;
 	}
 	auto expected = false;
@@ -78,21 +84,27 @@ bool Dcenter::acquireKeyCreation() {
 
 void Dcenter::releaseKeyCreationOnFail() {
 	Expects(_creatingKey);
-	Expects(_key == nullptr);
+	Expects(_temporaryKey == nullptr);
 
 	_creatingKey = false;
 }
 
-void Dcenter::releaseKeyCreationOnDone(const AuthKeyPtr &key) {
+void Dcenter::releaseKeyCreationOnDone(
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKey) {
 	Expects(_creatingKey);
-	Expects(_key == nullptr);
+	Expects(_temporaryKey == nullptr);
 
 	QWriteLocker lock(&_mutex);
-	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1), "
-		"emitting authKeyChanged, dc %2"
-		).arg(key ? key->keyId() : 0
+	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1, %2), "
+		"emitting authKeyChanged, dc %3"
+		).arg(temporaryKey ? temporaryKey->keyId() : 0
+		).arg(persistentKey ? persistentKey->keyId() : 0
 		).arg(_id));
-	_key = key;
+	_temporaryKey = temporaryKey;
+	if (persistentKey) {
+		_persistentKey = persistentKey;
+	}
 	_connectionInited = false;
 	_creatingKey = false;
 }
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/dcenter.h
index f935c8619..96326c425 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/dcenter.h
@@ -23,10 +23,13 @@ public:
 	// Thread-safe.
 	[[nodiscard]] DcId id() const;
 
-	[[nodiscard]] AuthKeyPtr getKey() const;
-	bool destroyCdnKey(uint64 keyId);
+	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
+	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
+	bool destroyTemporaryKey(uint64 keyId);
 	bool destroyConfirmedForgottenKey(uint64 keyId);
-	void releaseKeyCreationOnDone(const AuthKeyPtr &key);
+	void releaseKeyCreationOnDone(
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKey);
 
 	[[nodiscard]] bool connectionInited() const;
 	void setConnectionInited(bool connectionInited = true);
@@ -35,12 +38,11 @@ public:
 	void releaseKeyCreationOnFail();
 
 private:
-	bool destroyKey(uint64 keyId);
-
 	const DcId _id = 0;
 	mutable QReadWriteLock _mutex;
 
-	AuthKeyPtr _key;
+	AuthKeyPtr _temporaryKey;
+	AuthKeyPtr _persistentKey;
 	bool _connectionInited = false;
 	std::atomic<bool> _creatingKey = false;
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
similarity index 67%
rename from Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
index 81dded5d4..bd2f3686b 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
@@ -5,7 +5,7 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/details/mtproto_dc_key_checker.h"
+#include "mtproto/details/mtproto_dc_key_binder.h"
 
 #include "mtproto/mtp_instance.h"
 #include "base/unixtime.h"
@@ -17,8 +17,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace MTP::details {
 namespace {
 
-constexpr auto kBindKeyExpireTimeout = TimeId(3600);
-
 [[nodiscard]] QByteArray EncryptBindAuthKeyInner(
 		const AuthKeyPtr &persistentKey,
 		mtpMsgId realMsgId,
@@ -74,26 +72,28 @@ constexpr auto kBindKeyExpireTimeout = TimeId(3600);
 
 } // namespace
 
-DcKeyChecker::DcKeyChecker(
-	not_null<Instance*> instance,
-	ShiftedDcId shiftedDcId,
-	const AuthKeyPtr &persistentKey)
-: _instance(instance)
-, _shiftedDcId(shiftedDcId)
-, _persistentKey(persistentKey) {
+DcKeyBinder::DcKeyBinder(AuthKeyPtr &&persistentKey)
+: _persistentKey(std::move(persistentKey)) {
+	Expects(_persistentKey != nullptr);
 }
 
-SecureRequest DcKeyChecker::prepareRequest(
+bool DcKeyBinder::requested() const {
+	return _requestMsgId != 0;
+}
+
+SecureRequest DcKeyBinder::prepareRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId) {
 	Expects(_requestMsgId == 0);
+	Expects(temporaryKey != nullptr);
+	Expects(temporaryKey->expiresAt() != 0);
 
 	const auto nonce = openssl::RandomValue<uint64>();
 	_requestMsgId = base::unixtime::mtproto_msg_id();
 	auto result = SecureRequest::Serialize(MTPauth_BindTempAuthKey(
 		MTP_long(_persistentKey->keyId()),
 		MTP_long(nonce),
-		MTP_int(kBindKeyExpireTimeout),
+		MTP_int(temporaryKey->expiresAt()),
 		MTP_bytes(EncryptBindAuthKeyInner(
 			_persistentKey,
 			_requestMsgId,
@@ -102,49 +102,56 @@ SecureRequest DcKeyChecker::prepareRequest(
 				MTP_long(temporaryKey->keyId()),
 				MTP_long(_persistentKey->keyId()),
 				MTP_long(sessionId),
-				MTP_int(kBindKeyExpireTimeout))))));
+				MTP_int(temporaryKey->expiresAt()))))));
 	result.setMsgId(_requestMsgId);
 	return result;
 }
 
-bool DcKeyChecker::handleResponse(
+DcKeyBindState DcKeyBinder::handleResponse(
 		MTPlong requestMsgId,
 		const mtpBuffer &response) {
 	Expects(!response.isEmpty());
 
 	if (!_requestMsgId || requestMsgId.v != _requestMsgId) {
-		return false;
+		return DcKeyBindState::Unknown;
 	}
+	_requestMsgId = 0;
 
-	const auto destroyed = [&] {
-		if (response[0] != mtpc_rpc_error) {
-			return false;
-		}
-		auto error = MTPRpcError();
-		auto from = response.begin();
-		const auto end = from + response.size();
-		if (!error.read(from, end)) {
-			return false;
-		}
-		return error.match([&](const MTPDrpc_error &data) {
+	auto from = response.begin();
+	const auto end = from + response.size();
+	auto error = MTPRpcError();
+	auto result = MTPBool();
+	if (response[0] == mtpc_boolTrue) {
+		return DcKeyBindState::Success;
+	} else if (response[0] == mtpc_rpc_error && error.read(from, end)) {
+		const auto destroyed = error.match([&](const MTPDrpc_error &data) {
 			return (data.verror_code().v == 400)
 				&& (data.verror_message().v == "ENCRYPTED_MESSAGE_INVALID");
 		});
-	}();
+		return destroyed
+			? DcKeyBindState::DefinitelyDestroyed
+			: DcKeyBindState::Failed;
+	} else {
+		return DcKeyBindState::Failed;
+	}
+}
 
-	const auto instance = _instance;
-	const auto shiftedDcId = _shiftedDcId;
-	const auto keyId = _persistentKey->keyId();
-	_persistentKey->setLastCheckTime(crl::now());
-	crl::on_main(instance, [=] {
-		instance->killSession(shiftedDcId);
-		if (destroyed) {
-			instance->keyDestroyedOnServer(BareDcId(shiftedDcId), keyId);
-		}
+AuthKeyPtr DcKeyBinder::persistentKey() const {
+	return _persistentKey;
+}
+
+bool DcKeyBinder::IsDestroyedTemporaryKeyError(
+		const mtpBuffer &buffer) {
+	auto from = buffer.data();
+	const auto end = from + buffer.size();
+	auto error = MTPRpcError();
+	if (!error.read(from, from + buffer.size())) {
+		return false;
+	}
+	return error.match([&](const MTPDrpc_error &data) {
+		return (data.verror_code().v == 401)
+			&& (data.verror_message().v == "AUTH_KEY_PERM_EMPTY");
 	});
-
-	_requestMsgId = 0;
-	return true;
 }
 
 } // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
similarity index 58%
rename from Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
rename to Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
index 85d4a55da..2ea16f33e 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_checker.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
@@ -16,27 +16,31 @@ class Instance;
 
 namespace MTP::details {
 
-enum class DcKeyState {
-	MaybeExisting,
+enum class DcKeyBindState {
+	Unknown,
+	Success,
+	Failed,
 	DefinitelyDestroyed,
 };
 
-class DcKeyChecker final {
+class DcKeyBinder final {
 public:
-	DcKeyChecker(
-		not_null<Instance*> instance,
-		ShiftedDcId shiftedDcId,
-		const AuthKeyPtr &persistentKey);
+	DcKeyBinder(AuthKeyPtr &&persistentKey);
 
+	[[nodiscard]] bool requested() const;
 	[[nodiscard]] SecureRequest prepareRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId);
-	bool handleResponse(MTPlong requestMsgId, const mtpBuffer &response);
+	[[nodiscard]] DcKeyBindState handleResponse(
+		MTPlong requestMsgId,
+		const mtpBuffer &response);
+	[[nodiscard]] AuthKeyPtr persistentKey() const;
+
+	[[nodiscard]] static bool IsDestroyedTemporaryKeyError(
+		const mtpBuffer &buffer);
 
 private:
-	const not_null<Instance*> _instance;
-	const ShiftedDcId _shiftedDcId = 0;
-	const AuthKeyPtr _persistentKey;
+	AuthKeyPtr _persistentKey;
 	mtpMsgId _requestMsgId = 0;
 
 };
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index 7b1ca17f0..71f12b2ca 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -153,383 +153,50 @@ MTPint128 NonceDigest(bytes::const_span data) {
 
 } // namespace
 
+DcKeyCreator::Attempt::~Attempt() {
+	const auto clearBytes = [](bytes::span bytes) {
+		OPENSSL_cleanse(bytes.data(), bytes.size());
+	};
+	OPENSSL_cleanse(&data, sizeof(data));
+	clearBytes(dhPrime);
+	clearBytes(g_a);
+	clearBytes(authKey);
+}
+
 DcKeyCreator::DcKeyCreator(
 	DcId dcId,
 	int16 protocolDcId,
 	not_null<AbstractConnection*> connection,
 	not_null<DcOptions*> dcOptions,
 	Delegate delegate,
-	TimeId expireIn)
+	Request request)
 : _connection(connection)
 , _dcOptions(dcOptions)
 , _dcId(dcId)
 , _protocolDcId(protocolDcId)
-, _expireIn(expireIn)
+, _request(request)
 , _delegate(std::move(delegate)) {
-	Expects(_expireIn >= 0);
+	Expects(_request.temporaryExpiresIn > 0);
 	Expects(_delegate.done != nullptr);
 
-	_data.nonce = openssl::RandomValue<MTPint128>();
-	pqSend();
+	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
+		answered();
+	});
+
+	pqSend(&_temporary, _request.temporaryExpiresIn);
+	if (_request.persistentNeeded) {
+		pqSend(&_persistent, 0);
+	}
 }
 
 DcKeyCreator::~DcKeyCreator() {
 	if (_delegate.done) {
 		stopReceiving();
 	}
-	const auto clearBytes = [](bytes::span bytes) {
-		OPENSSL_cleanse(bytes.data(), bytes.size());
-	};
-	OPENSSL_cleanse(&_data, sizeof(_data));
-	clearBytes(_dhPrime);
-	clearBytes(_g_a);
-	clearBytes(_authKey);
 }
 
-void DcKeyCreator::pqSend() {
-	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
-		pqAnswered();
-	});
-
-	DEBUG_LOG(("AuthKey Info: sending Req_pq..."));
-	sendNotSecureRequest(MTPReq_pq_multi(_data.nonce));
-}
-
-void DcKeyCreator::pqAnswered() {
-	stopReceiving();
-	DEBUG_LOG(("AuthKey Info: receiving Req_pq answer..."));
-
-	MTPReq_pq::ResponseType res_pq;
-	if (!readNotSecureResponse(res_pq)) {
-		return failed();
-	}
-
-	auto &res_pq_data = res_pq.c_resPQ();
-	if (res_pq_data.vnonce() != _data.nonce) {
-		LOG(("AuthKey Error: received nonce <> sent nonce (in res_pq)!"));
-		DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&res_pq_data.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-		return failed();
-	}
-
-	const auto rsaKey = _dcOptions->getDcRSAKey(
-		_dcId,
-		res_pq.c_resPQ().vserver_public_key_fingerprints().v);
-	if (!rsaKey.valid()) {
-		return failed(Error::UnknownPublicKey);
-	}
-
-	_data.server_nonce = res_pq_data.vserver_nonce();
-	_data.new_nonce = openssl::RandomValue<MTPint256>();
-
-	const auto &pq = res_pq_data.vpq().v;
-	const auto parsed = ParsePQ(res_pq_data.vpq().v);
-	if (parsed.p.isEmpty() || parsed.q.isEmpty()) {
-		LOG(("AuthKey Error: could not factor pq!"));
-		DEBUG_LOG(("AuthKey Error: problematic pq: %1").arg(Logs::mb(pq.constData(), pq.length()).str()));
-		return failed();
-	}
-
-	const auto dhEncString = [&] {
-		return (_expireIn == 0)
-			? EncryptPQInnerRSA(
-				MTP_p_q_inner_data_dc(
-					res_pq_data.vpq(),
-					MTP_bytes(parsed.p),
-					MTP_bytes(parsed.q),
-					_data.nonce,
-					_data.server_nonce,
-					_data.new_nonce,
-					MTP_int(_protocolDcId)),
-				rsaKey)
-			: EncryptPQInnerRSA(
-				MTP_p_q_inner_data_temp_dc(
-					res_pq_data.vpq(),
-					MTP_bytes(parsed.p),
-					MTP_bytes(parsed.q),
-					_data.nonce,
-					_data.server_nonce,
-					_data.new_nonce,
-					MTP_int(_protocolDcId),
-					MTP_int(_expireIn)),
-				rsaKey);
-	}();
-	if (dhEncString.empty()) {
-		return failed();
-	}
-
-	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
-		dhParamsAnswered();
-	});
-
-	DEBUG_LOG(("AuthKey Info: sending Req_DH_params..."));
-
-	sendNotSecureRequest(MTPReq_DH_params(
-		_data.nonce,
-		_data.server_nonce,
-		MTP_bytes(parsed.p),
-		MTP_bytes(parsed.q),
-		MTP_long(rsaKey.fingerprint()),
-		MTP_bytes(dhEncString)));
-}
-
-void DcKeyCreator::dhParamsAnswered() {
-	stopReceiving();
-	DEBUG_LOG(("AuthKey Info: receiving Req_DH_params answer..."));
-
-	MTPReq_DH_params::ResponseType res_DH_params;
-	if (!readNotSecureResponse(res_DH_params)) {
-		return failed();
-	}
-
-	switch (res_DH_params.type()) {
-	case mtpc_server_DH_params_ok: {
-		const auto &encDH(res_DH_params.c_server_DH_params_ok());
-		if (encDH.vnonce() != _data.nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_params_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&encDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-			return failed();
-		}
-		if (encDH.vserver_nonce() != _data.server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&encDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
-			return failed();
-		}
-
-		auto &encDHStr = encDH.vencrypted_answer().v;
-		uint32 encDHLen = encDHStr.length(), encDHBufLen = encDHLen >> 2;
-		if ((encDHLen & 0x03) || encDHBufLen < 6) {
-			LOG(("AuthKey Error: bad encrypted data length %1 (in server_DH_params_ok)!").arg(encDHLen));
-			DEBUG_LOG(("AuthKey Error: received encrypted data %1").arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
-			return failed();
-		}
-
-		const auto nlen = sizeof(_data.new_nonce);
-		const auto slen = sizeof(_data.server_nonce);
-		auto tmp_aes_buffer = bytes::array<1024>();
-		const auto tmp_aes = bytes::make_span(tmp_aes_buffer);
-		bytes::copy(tmp_aes, bytes::object_as_span(&_data.new_nonce));
-		bytes::copy(tmp_aes.subspan(nlen), bytes::object_as_span(&_data.server_nonce));
-		bytes::copy(tmp_aes.subspan(nlen + slen), bytes::object_as_span(&_data.new_nonce));
-		bytes::copy(tmp_aes.subspan(nlen + slen + nlen), bytes::object_as_span(&_data.new_nonce));
-		const auto sha1ns = openssl::Sha1(tmp_aes.subspan(0, nlen + slen));
-		const auto sha1sn = openssl::Sha1(tmp_aes.subspan(nlen, nlen + slen));
-		const auto sha1nn = openssl::Sha1(tmp_aes.subspan(nlen + slen, nlen + nlen));
-
-		mtpBuffer decBuffer;
-		decBuffer.resize(encDHBufLen);
-
-		const auto aesKey = bytes::make_span(_data.aesKey);
-		const auto aesIV = bytes::make_span(_data.aesIV);
-		bytes::copy(aesKey, bytes::make_span(sha1ns).subspan(0, 20));
-		bytes::copy(aesKey.subspan(20), bytes::make_span(sha1sn).subspan(0, 12));
-		bytes::copy(aesIV, bytes::make_span(sha1sn).subspan(12, 8));
-		bytes::copy(aesIV.subspan(8), bytes::make_span(sha1nn).subspan(0, 20));
-		bytes::copy(aesIV.subspan(28), bytes::object_as_span(&_data.new_nonce).subspan(0, 4));
-
-		aesIgeDecryptRaw(encDHStr.constData(), &decBuffer[0], encDHLen, aesKey.data(), aesIV.data());
-
-		const mtpPrime *from(&decBuffer[5]), *to(from), *end(from + (encDHBufLen - 5));
-		MTPServer_DH_inner_data dh_inner;
-		if (!dh_inner.read(to, end)) {
-			LOG(("AuthKey Error: could not decrypt server_DH_inner_data!"));
-			return failed();
-		}
-		const auto &dh_inner_data(dh_inner.c_server_DH_inner_data());
-		if (dh_inner_data.vnonce() != _data.nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_inner_data)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&dh_inner_data.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-			return failed();
-		}
-		if (dh_inner_data.vserver_nonce() != _data.server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_inner_data)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&dh_inner_data.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
-			return failed();
-		}
-		const auto sha1Buffer = openssl::Sha1(
-			bytes::make_span(decBuffer).subspan(
-				5 * sizeof(mtpPrime),
-				(to - from) * sizeof(mtpPrime)));
-		const auto sha1Dec = bytes::make_span(decBuffer).subspan(
-			0,
-			openssl::kSha1Size);
-		if (bytes::compare(sha1Dec, sha1Buffer)) {
-			LOG(("AuthKey Error: sha1 hash of encrypted part did not match!"));
-			DEBUG_LOG(("AuthKey Error: sha1 did not match, server_nonce: %1, new_nonce %2, encrypted data %3").arg(Logs::mb(&_data.server_nonce, 16).str()).arg(Logs::mb(&_data.new_nonce, 16).str()).arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
-			return failed();
-		}
-		base::unixtime::update(dh_inner_data.vserver_time().v);
-
-		// check that dhPrime and (dhPrime - 1) / 2 are really prime
-		if (!IsPrimeAndGood(bytes::make_span(dh_inner_data.vdh_prime().v), dh_inner_data.vg().v)) {
-			LOG(("AuthKey Error: bad dh_prime primality!"));
-			return failed();
-		}
-
-		_dhPrime = bytes::make_vector(
-			dh_inner_data.vdh_prime().v);
-		_data.g = dh_inner_data.vg().v;
-		_g_a = bytes::make_vector(dh_inner_data.vg_a().v);
-		_data.retry_id = MTP_long(0);
-		_data.retries = 0;
-	} return dhClientParamsSend();
-
-	case mtpc_server_DH_params_fail: {
-		const auto &encDH(res_DH_params.c_server_DH_params_fail());
-		if (encDH.vnonce() != _data.nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_params_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&encDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-			return failed();
-		}
-		if (encDH.vserver_nonce() != _data.server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&encDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
-			return failed();
-		}
-		if (encDH.vnew_nonce_hash() != NonceDigest(bytes::object_as_span(&_data.new_nonce))) {
-			LOG(("AuthKey Error: received new_nonce_hash did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash: %1, new_nonce: %2").arg(Logs::mb(&encDH.vnew_nonce_hash(), 16).str()).arg(Logs::mb(&_data.new_nonce, 32).str()));
-			return failed();
-		}
-		LOG(("AuthKey Error: server_DH_params_fail received!"));
-	} return failed();
-
-	}
-	LOG(("AuthKey Error: unknown server_DH_params received, typeId = %1").arg(res_DH_params.type()));
-	return failed();
-}
-
-void DcKeyCreator::dhClientParamsSend() {
-	if (++_data.retries > 5) {
-		LOG(("AuthKey Error: could not create auth_key for %1 retries").arg(_data.retries - 1));
-		return failed();
-	}
-
-	// gen rand 'b'
-	auto randomSeed = bytes::vector(ModExpFirst::kRandomPowerSize);
-	bytes::set_random(randomSeed);
-	auto g_b_data = CreateModExp(_data.g, _dhPrime, randomSeed);
-	if (g_b_data.modexp.empty()) {
-		LOG(("AuthKey Error: could not generate good g_b."));
-		return failed();
-	}
-
-	auto computedAuthKey = CreateAuthKey(_g_a, g_b_data.randomPower, _dhPrime);
-	if (computedAuthKey.empty()) {
-		LOG(("AuthKey Error: could not generate auth_key."));
-		return failed();
-	}
-	AuthKey::FillData(_authKey, computedAuthKey);
-
-	auto auth_key_sha = openssl::Sha1(_authKey);
-	memcpy(&_data.auth_key_aux_hash, auth_key_sha.data(), 8);
-	memcpy(&_data.auth_key_hash, auth_key_sha.data() + 12, 8);
-
-	const auto client_dh_inner = MTP_client_DH_inner_data(
-		_data.nonce,
-		_data.server_nonce,
-		_data.retry_id,
-		MTP_bytes(g_b_data.modexp));
-
-	auto sdhEncString = EncryptClientDHInner(
-		client_dh_inner,
-		_data.aesKey.data(),
-		_data.aesIV.data());
-
-	QObject::connect(_connection, &AbstractConnection::receivedData, [=] {
-		dhClientParamsAnswered();
-	});
-
-	DEBUG_LOG(("AuthKey Info: sending Req_client_DH_params..."));
-	sendNotSecureRequest(MTPSet_client_DH_params(
-		_data.nonce,
-		_data.server_nonce,
-		MTP_string(std::move(sdhEncString))));
-}
-
-void DcKeyCreator::dhClientParamsAnswered() {
-	stopReceiving();
-	DEBUG_LOG(("AuthKey Info: receiving Req_client_DH_params answer..."));
-
-	MTPSet_client_DH_params::ResponseType res_client_DH_params;
-	if (!readNotSecureResponse(res_client_DH_params)) {
-		return failed();
-	}
-
-	switch (res_client_DH_params.type()) {
-	case mtpc_dh_gen_ok: {
-		const auto &resDH(res_client_DH_params.c_dh_gen_ok());
-		if (resDH.vnonce() != _data.nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-			return failed();
-		}
-		if (resDH.vserver_nonce() != _data.server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_ok)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
-			return failed();
-		}
-		_data.new_nonce_buf[32] = bytes::type(1);
-		if (resDH.vnew_nonce_hash1() != NonceDigest(_data.new_nonce_buf)) {
-			LOG(("AuthKey Error: received new_nonce_hash1 did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash1: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash1(), 16).str()).arg(Logs::mb(_data.new_nonce_buf.data(), 41).str()));
-			return failed();
-		}
-
-		uint64 salt1 = _data.new_nonce.l.l, salt2 = _data.server_nonce.l;
-		done(salt1 ^ salt2);
-	} return;
-
-	case mtpc_dh_gen_retry: {
-		const auto &resDH(res_client_DH_params.c_dh_gen_retry());
-		if (resDH.vnonce() != _data.nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_retry)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-			return failed();
-		}
-		if (resDH.vserver_nonce() != _data.server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_retry)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
-			return failed();
-		}
-		_data.new_nonce_buf[32] = bytes::type(2);
-		uchar sha1Buffer[20];
-		if (resDH.vnew_nonce_hash2() != NonceDigest(_data.new_nonce_buf)) {
-			LOG(("AuthKey Error: received new_nonce_hash2 did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash2: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash2(), 16).str()).arg(Logs::mb(_data.new_nonce_buf.data(), 41).str()));
-			return failed();
-		}
-		_data.retry_id = _data.auth_key_aux_hash;
-	} return dhClientParamsSend();
-
-	case mtpc_dh_gen_fail: {
-		const auto &resDH(res_client_DH_params.c_dh_gen_fail());
-		if (resDH.vnonce() != _data.nonce) {
-			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&resDH.vnonce(), 16).str()).arg(Logs::mb(&_data.nonce, 16).str()));
-			return failed();
-		}
-		if (resDH.vserver_nonce() != _data.server_nonce) {
-			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_fail)!"));
-			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&resDH.vserver_nonce(), 16).str()).arg(Logs::mb(&_data.server_nonce, 16).str()));
-			return failed();
-		}
-		_data.new_nonce_buf[32] = bytes::type(3);
-		uchar sha1Buffer[20];
-		if (resDH.vnew_nonce_hash3() != NonceDigest(_data.new_nonce_buf)) {
-			LOG(("AuthKey Error: received new_nonce_hash3 did not match!"));
-			DEBUG_LOG(("AuthKey Error: received new_nonce_hash3: %1, new_nonce_buf: %2").arg(Logs::mb(&resDH.vnew_nonce_hash3(), 16).str()).arg(Logs::mb(_data.new_nonce_buf.data(), 41).str()));
-			return failed();
-		}
-		LOG(("AuthKey Error: dh_gen_fail received!"));
-	} return failed();
-	}
-
-	LOG(("AuthKey Error: unknown set_client_DH_params_answer received, typeId = %1").arg(res_client_DH_params.type()));
-	return failed();
-}
-
-template <typename Request>
-void DcKeyCreator::sendNotSecureRequest(const Request &request) {
+template <typename RequestType>
+void DcKeyCreator::sendNotSecureRequest(const RequestType &request) {
 	auto packet = _connection->prepareNotSecurePacket(
 		request,
 		base::unixtime::mtproto_msg_id());
@@ -547,8 +214,18 @@ void DcKeyCreator::sendNotSecureRequest(const Request &request) {
 	}
 }
 
-template <typename Response>
-bool DcKeyCreator::readNotSecureResponse(Response &response) {
+template <typename RequestType, typename Response>
+std::optional<Response> DcKeyCreator::readNotSecureResponse(
+		gsl::span<const mtpPrime> answer) {
+	auto from = answer.data();
+	auto result = Response();
+	if (result.read(from, from + answer.size())) {
+		return result;
+	}
+	return std::nullopt;
+}
+
+void DcKeyCreator::answered() {
 	if (_delegate.receivedSome) {
 		_delegate.receivedSome();
 	}
@@ -556,7 +233,7 @@ bool DcKeyCreator::readNotSecureResponse(Response &response) {
 	if (_connection->received().empty()) {
 		LOG(("AuthKey Error: "
 			"trying to read response from empty received list"));
-		return false;
+		return failed();
 	}
 
 	const auto buffer = std::move(_connection->received().front());
@@ -564,10 +241,358 @@ bool DcKeyCreator::readNotSecureResponse(Response &response) {
 
 	const auto answer = _connection->parseNotSecureResponse(buffer);
 	if (answer.empty()) {
-		return false;
+		return failed();
 	}
-	auto from = answer.data();
-	return response.read(from, from + answer.size());
+
+	handleAnswer(answer);
+}
+
+DcKeyCreator::Attempt *DcKeyCreator::attemptByNonce(const MTPint128 &nonce) {
+	if (_temporary.data.nonce == nonce) {
+		DEBUG_LOG(("AuthKey Info: receiving answer for temporary..."));
+		return &_temporary;
+	} else if (_persistent.data.nonce == nonce) {
+		DEBUG_LOG(("AuthKey Info: receiving answer for persistent..."));
+		return &_persistent;
+	}
+	LOG(("AuthKey Error: attempt by nonce not found."));
+	return nullptr;
+}
+
+void DcKeyCreator::handleAnswer(gsl::span<const mtpPrime> answer) {
+	if (const auto resPQ = readNotSecureResponse<MTPReq_pq>(answer)) {
+		const auto nonce = resPQ->match([](const auto &data) {
+			return data.vnonce();
+		});
+		if (const auto attempt = attemptByNonce(nonce)) {
+			DEBUG_LOG(("AuthKey Info: receiving Req_pq answer..."));
+			return pqAnswered(attempt, *resPQ);
+		}
+	} else if (const auto resDH = readNotSecureResponse<MTPReq_DH_params>(answer)) {
+		const auto nonce = resDH->match([](const auto &data) {
+			return data.vnonce();
+		});
+		if (const auto attempt = attemptByNonce(nonce)) {
+			DEBUG_LOG(("AuthKey Info: receiving Req_DH_params answer..."));
+			return dhParamsAnswered(attempt, *resDH);
+		}
+	} else if (const auto result = readNotSecureResponse<MTPSet_client_DH_params>(answer)) {
+		const auto nonce = result->match([](const auto &data) {
+			return data.vnonce();
+		});
+		if (const auto attempt = attemptByNonce(nonce)) {
+			DEBUG_LOG(("AuthKey Info: receiving Req_client_DH_params answer..."));
+			return dhClientParamsAnswered(attempt, *result);
+		}
+	}
+	LOG(("AuthKey Error: Unknown answer received."));
+	failed();
+}
+
+void DcKeyCreator::pqSend(not_null<Attempt*> attempt, TimeId expiresIn) {
+	DEBUG_LOG(("AuthKey Info: sending Req_pq for %1..."
+		).arg(expiresIn ? "temporary" : "persistent"));
+	attempt->stage = Stage::WaitingPQ;
+	attempt->expiresIn = expiresIn;
+	attempt->data.nonce = openssl::RandomValue<MTPint128>();
+	sendNotSecureRequest(MTPReq_pq_multi(attempt->data.nonce));
+}
+
+void DcKeyCreator::pqAnswered(
+		not_null<Attempt*> attempt,
+		const MTPresPQ &data) {
+	data.match([&](const MTPDresPQ &data) {
+		Expects(data.vnonce() == attempt->data.nonce);
+
+		if (attempt->stage != Stage::WaitingPQ) {
+			LOG(("AuthKey Error: Unexpected stage %1").arg(int(attempt->stage)));
+			return failed();
+		}
+		const auto rsaKey = _dcOptions->getDcRSAKey(
+			_dcId,
+			data.vserver_public_key_fingerprints().v);
+		if (!rsaKey.valid()) {
+			return failed(Error::UnknownPublicKey);
+		}
+
+		attempt->data.server_nonce = data.vserver_nonce();
+		attempt->data.new_nonce = openssl::RandomValue<MTPint256>();
+
+		const auto &pq = data.vpq().v;
+		const auto parsed = ParsePQ(data.vpq().v);
+		if (parsed.p.isEmpty() || parsed.q.isEmpty()) {
+			LOG(("AuthKey Error: could not factor pq!"));
+			DEBUG_LOG(("AuthKey Error: problematic pq: %1").arg(Logs::mb(pq.constData(), pq.length()).str()));
+			return failed();
+		}
+
+		const auto dhEncString = [&] {
+			return (attempt->expiresIn == 0)
+				? EncryptPQInnerRSA(
+					MTP_p_q_inner_data_dc(
+						data.vpq(),
+						MTP_bytes(parsed.p),
+						MTP_bytes(parsed.q),
+						attempt->data.nonce,
+						attempt->data.server_nonce,
+						attempt->data.new_nonce,
+						MTP_int(_protocolDcId)),
+					rsaKey)
+				: EncryptPQInnerRSA(
+					MTP_p_q_inner_data_temp_dc(
+						data.vpq(),
+						MTP_bytes(parsed.p),
+						MTP_bytes(parsed.q),
+						attempt->data.nonce,
+						attempt->data.server_nonce,
+						attempt->data.new_nonce,
+						MTP_int(_protocolDcId),
+						MTP_int(attempt->expiresIn)),
+					rsaKey);
+		}();
+		if (dhEncString.empty()) {
+			return failed();
+		}
+
+		attempt->stage = Stage::WaitingDH;
+		DEBUG_LOG(("AuthKey Info: sending Req_DH_params..."));
+		sendNotSecureRequest(MTPReq_DH_params(
+			attempt->data.nonce,
+			attempt->data.server_nonce,
+			MTP_bytes(parsed.p),
+			MTP_bytes(parsed.q),
+			MTP_long(rsaKey.fingerprint()),
+			MTP_bytes(dhEncString)));
+	});
+}
+
+void DcKeyCreator::dhParamsAnswered(
+		not_null<Attempt*> attempt,
+		const MTPserver_DH_Params &data) {
+	if (attempt->stage != Stage::WaitingDH) {
+		LOG(("AuthKey Error: Unexpected stage %1").arg(int(attempt->stage)));
+		return failed();
+	}
+	data.match([&](const MTPDserver_DH_params_ok &data) {
+		Expects(data.vnonce() == attempt->data.nonce);
+
+		if (data.vserver_nonce() != attempt->data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&data.vserver_nonce(), 16).str()).arg(Logs::mb(&attempt->data.server_nonce, 16).str()));
+			return failed();
+		}
+
+		auto &encDHStr = data.vencrypted_answer().v;
+		uint32 encDHLen = encDHStr.length(), encDHBufLen = encDHLen >> 2;
+		if ((encDHLen & 0x03) || encDHBufLen < 6) {
+			LOG(("AuthKey Error: bad encrypted data length %1 (in server_DH_params_ok)!").arg(encDHLen));
+			DEBUG_LOG(("AuthKey Error: received encrypted data %1").arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
+			return failed();
+		}
+
+		const auto nlen = sizeof(attempt->data.new_nonce);
+		const auto slen = sizeof(attempt->data.server_nonce);
+		auto tmp_aes_buffer = bytes::array<1024>();
+		const auto tmp_aes = bytes::make_span(tmp_aes_buffer);
+		bytes::copy(tmp_aes, bytes::object_as_span(&attempt->data.new_nonce));
+		bytes::copy(tmp_aes.subspan(nlen), bytes::object_as_span(&attempt->data.server_nonce));
+		bytes::copy(tmp_aes.subspan(nlen + slen), bytes::object_as_span(&attempt->data.new_nonce));
+		bytes::copy(tmp_aes.subspan(nlen + slen + nlen), bytes::object_as_span(&attempt->data.new_nonce));
+		const auto sha1ns = openssl::Sha1(tmp_aes.subspan(0, nlen + slen));
+		const auto sha1sn = openssl::Sha1(tmp_aes.subspan(nlen, nlen + slen));
+		const auto sha1nn = openssl::Sha1(tmp_aes.subspan(nlen + slen, nlen + nlen));
+
+		mtpBuffer decBuffer;
+		decBuffer.resize(encDHBufLen);
+
+		const auto aesKey = bytes::make_span(attempt->data.aesKey);
+		const auto aesIV = bytes::make_span(attempt->data.aesIV);
+		bytes::copy(aesKey, bytes::make_span(sha1ns).subspan(0, 20));
+		bytes::copy(aesKey.subspan(20), bytes::make_span(sha1sn).subspan(0, 12));
+		bytes::copy(aesIV, bytes::make_span(sha1sn).subspan(12, 8));
+		bytes::copy(aesIV.subspan(8), bytes::make_span(sha1nn).subspan(0, 20));
+		bytes::copy(aesIV.subspan(28), bytes::object_as_span(&attempt->data.new_nonce).subspan(0, 4));
+
+		aesIgeDecryptRaw(encDHStr.constData(), &decBuffer[0], encDHLen, aesKey.data(), aesIV.data());
+
+		const mtpPrime *from(&decBuffer[5]), *to(from), *end(from + (encDHBufLen - 5));
+		MTPServer_DH_inner_data dh_inner;
+		if (!dh_inner.read(to, end)) {
+			LOG(("AuthKey Error: could not decrypt server_DH_inner_data!"));
+			return failed();
+		}
+		const auto &dh_inner_data(dh_inner.c_server_DH_inner_data());
+		if (dh_inner_data.vnonce() != attempt->data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in server_DH_inner_data)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&dh_inner_data.vnonce(), 16).str()).arg(Logs::mb(&attempt->data.nonce, 16).str()));
+			return failed();
+		}
+		if (dh_inner_data.vserver_nonce() != attempt->data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_inner_data)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&dh_inner_data.vserver_nonce(), 16).str()).arg(Logs::mb(&attempt->data.server_nonce, 16).str()));
+			return failed();
+		}
+		const auto sha1Buffer = openssl::Sha1(
+			bytes::make_span(decBuffer).subspan(
+				5 * sizeof(mtpPrime),
+				(to - from) * sizeof(mtpPrime)));
+		const auto sha1Dec = bytes::make_span(decBuffer).subspan(
+			0,
+			openssl::kSha1Size);
+		if (bytes::compare(sha1Dec, sha1Buffer)) {
+			LOG(("AuthKey Error: sha1 hash of encrypted part did not match!"));
+			DEBUG_LOG(("AuthKey Error: sha1 did not match, server_nonce: %1, new_nonce %2, encrypted data %3").arg(Logs::mb(&attempt->data.server_nonce, 16).str()).arg(Logs::mb(&attempt->data.new_nonce, 16).str()).arg(Logs::mb(encDHStr.constData(), encDHLen).str()));
+			return failed();
+		}
+		base::unixtime::update(dh_inner_data.vserver_time().v);
+
+		// check that dhPrime and (dhPrime - 1) / 2 are really prime
+		if (!IsPrimeAndGood(bytes::make_span(dh_inner_data.vdh_prime().v), dh_inner_data.vg().v)) {
+			LOG(("AuthKey Error: bad dh_prime primality!"));
+			return failed();
+		}
+
+		attempt->dhPrime = bytes::make_vector(
+			dh_inner_data.vdh_prime().v);
+		attempt->data.g = dh_inner_data.vg().v;
+		attempt->g_a = bytes::make_vector(dh_inner_data.vg_a().v);
+		attempt->data.retry_id = MTP_long(0);
+		attempt->retries = 0;
+		dhClientParamsSend(attempt);
+	}, [&](const MTPDserver_DH_params_fail &data) {
+		Expects(data.vnonce() == attempt->data.nonce);
+
+		if (data.vserver_nonce() != attempt->data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in server_DH_params_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&data.vserver_nonce(), 16).str()).arg(Logs::mb(&attempt->data.server_nonce, 16).str()));
+			return failed();
+		}
+		if (data.vnew_nonce_hash() != NonceDigest(bytes::object_as_span(&attempt->data.new_nonce))) {
+			LOG(("AuthKey Error: received new_nonce_hash did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash: %1, new_nonce: %2").arg(Logs::mb(&data.vnew_nonce_hash(), 16).str()).arg(Logs::mb(&attempt->data.new_nonce, 32).str()));
+			return failed();
+		}
+		LOG(("AuthKey Error: server_DH_params_fail received!"));
+		failed();
+	});
+}
+
+void DcKeyCreator::dhClientParamsSend(not_null<Attempt*> attempt) {
+	if (++attempt->retries > 5) {
+		LOG(("AuthKey Error: could not create auth_key for %1 retries").arg(attempt->retries - 1));
+		return failed();
+	}
+
+	// gen rand 'b'
+	auto randomSeed = bytes::vector(ModExpFirst::kRandomPowerSize);
+	bytes::set_random(randomSeed);
+	auto g_b_data = CreateModExp(attempt->data.g, attempt->dhPrime, randomSeed);
+	if (g_b_data.modexp.empty()) {
+		LOG(("AuthKey Error: could not generate good g_b."));
+		return failed();
+	}
+
+	auto computedAuthKey = CreateAuthKey(attempt->g_a, g_b_data.randomPower, attempt->dhPrime);
+	if (computedAuthKey.empty()) {
+		LOG(("AuthKey Error: could not generate auth_key."));
+		return failed();
+	}
+	AuthKey::FillData(attempt->authKey, computedAuthKey);
+
+	auto auth_key_sha = openssl::Sha1(attempt->authKey);
+	memcpy(&attempt->data.auth_key_aux_hash, auth_key_sha.data(), 8);
+	memcpy(&attempt->data.auth_key_hash, auth_key_sha.data() + 12, 8);
+
+	const auto client_dh_inner = MTP_client_DH_inner_data(
+		attempt->data.nonce,
+		attempt->data.server_nonce,
+		attempt->data.retry_id,
+		MTP_bytes(g_b_data.modexp));
+
+	auto sdhEncString = EncryptClientDHInner(
+		client_dh_inner,
+		attempt->data.aesKey.data(),
+		attempt->data.aesIV.data());
+
+	attempt->stage = Stage::WaitingDone;
+	DEBUG_LOG(("AuthKey Info: sending Req_client_DH_params..."));
+	sendNotSecureRequest(MTPSet_client_DH_params(
+		attempt->data.nonce,
+		attempt->data.server_nonce,
+		MTP_string(std::move(sdhEncString))));
+}
+
+void DcKeyCreator::dhClientParamsAnswered(
+		not_null<Attempt*> attempt,
+		const MTPset_client_DH_params_answer &data) {
+	if (attempt->stage != Stage::WaitingDone) {
+		LOG(("AuthKey Error: Unexpected stage %1").arg(int(attempt->stage)));
+		return failed();
+	}
+
+	data.match([&](const MTPDdh_gen_ok &data) {
+		if (data.vnonce() != attempt->data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&data.vnonce(), 16).str()).arg(Logs::mb(&attempt->data.nonce, 16).str()));
+			return failed();
+		}
+		if (data.vserver_nonce() != attempt->data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_ok)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&data.vserver_nonce(), 16).str()).arg(Logs::mb(&attempt->data.server_nonce, 16).str()));
+			return failed();
+		}
+		attempt->data.new_nonce_buf[32] = bytes::type(1);
+		if (data.vnew_nonce_hash1() != NonceDigest(attempt->data.new_nonce_buf)) {
+			LOG(("AuthKey Error: received new_nonce_hash1 did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash1: %1, new_nonce_buf: %2").arg(Logs::mb(&data.vnew_nonce_hash1(), 16).str()).arg(Logs::mb(attempt->data.new_nonce_buf.data(), 41).str()));
+			return failed();
+		}
+
+		uint64 salt1 = attempt->data.new_nonce.l.l, salt2 = attempt->data.server_nonce.l;
+		attempt->data.doneSalt = salt1 ^ salt2;
+		attempt->stage = Stage::Ready;
+		done();
+	}, [&](const MTPDdh_gen_retry &data) {
+		if (data.vnonce() != attempt->data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_retry)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&data.vnonce(), 16).str()).arg(Logs::mb(&attempt->data.nonce, 16).str()));
+			return failed();
+		}
+		if (data.vserver_nonce() != attempt->data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_retry)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&data.vserver_nonce(), 16).str()).arg(Logs::mb(&attempt->data.server_nonce, 16).str()));
+			return failed();
+		}
+		attempt->data.new_nonce_buf[32] = bytes::type(2);
+		uchar sha1Buffer[20];
+		if (data.vnew_nonce_hash2() != NonceDigest(attempt->data.new_nonce_buf)) {
+			LOG(("AuthKey Error: received new_nonce_hash2 did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash2: %1, new_nonce_buf: %2").arg(Logs::mb(&data.vnew_nonce_hash2(), 16).str()).arg(Logs::mb(attempt->data.new_nonce_buf.data(), 41).str()));
+			return failed();
+		}
+		attempt->data.retry_id = attempt->data.auth_key_aux_hash;
+		dhClientParamsSend(attempt);
+	}, [&](const MTPDdh_gen_fail &data) {
+		if (data.vnonce() != attempt->data.nonce) {
+			LOG(("AuthKey Error: received nonce <> sent nonce (in dh_gen_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received nonce: %1, sent nonce: %2").arg(Logs::mb(&data.vnonce(), 16).str()).arg(Logs::mb(&attempt->data.nonce, 16).str()));
+			return failed();
+		}
+		if (data.vserver_nonce() != attempt->data.server_nonce) {
+			LOG(("AuthKey Error: received server_nonce <> sent server_nonce (in dh_gen_fail)!"));
+			DEBUG_LOG(("AuthKey Error: received server_nonce: %1, sent server_nonce: %2").arg(Logs::mb(&data.vserver_nonce(), 16).str()).arg(Logs::mb(&attempt->data.server_nonce, 16).str()));
+			return failed();
+		}
+		attempt->data.new_nonce_buf[32] = bytes::type(3);
+		uchar sha1Buffer[20];
+		if (data.vnew_nonce_hash3() != NonceDigest(attempt->data.new_nonce_buf)) {
+			LOG(("AuthKey Error: received new_nonce_hash3 did not match!"));
+			DEBUG_LOG(("AuthKey Error: received new_nonce_hash3: %1, new_nonce_buf: %2").arg(Logs::mb(&data.vnew_nonce_hash3(), 16).str()).arg(Logs::mb(attempt->data.new_nonce_buf.data(), 41).str()));
+			return failed();
+		}
+		LOG(("AuthKey Error: dh_gen_fail received!"));
+		failed();
+	});
 }
 
 void DcKeyCreator::failed(Error error) {
@@ -576,13 +601,28 @@ void DcKeyCreator::failed(Error error) {
 	onstack(tl::unexpected(error));
 }
 
-void DcKeyCreator::done(uint64 serverSalt) {
+void DcKeyCreator::done() {
+	Expects(_temporary.stage != Stage::None);
+
+	if (_persistent.stage != Stage::None && _persistent.stage != Stage::Ready) {
+		return;
+	} else if (_temporary.stage != Stage::Ready) {
+		return;
+	}
+
 	auto result = Result();
-	result.key = std::make_shared<AuthKey>(
-		AuthKey::Type::Generated,
+	result.temporaryKey = std::make_shared<AuthKey>(
+		AuthKey::Type::Temporary,
 		_dcId,
-		_authKey);
-	result.serverSalt = serverSalt;
+		_temporary.authKey);
+	result.temporaryServerSalt = _temporary.data.doneSalt;
+	if (_persistent.stage == Stage::Ready) {
+		result.persistentKey = std::make_shared<AuthKey>(
+			AuthKey::Type::Generated,
+			_dcId,
+			_persistent.authKey);
+		result.persistentServerSalt = _persistent.data.doneSalt;
+	}
 
 	stopReceiving();
 	auto onstack = base::take(_delegate.done);
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
index 23dcadbd6..e98312694 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -23,13 +23,19 @@ using namespace ::MTP::internal;
 
 class DcKeyCreator final {
 public:
+	struct Request {
+		TimeId temporaryExpiresIn = 0;
+		bool persistentNeeded = false;
+	};
 	enum class Error {
 		UnknownPublicKey,
 		Other,
 	};
 	struct Result {
-		AuthKeyPtr key;
-		uint64 serverSalt = 0;
+		AuthKeyPtr persistentKey;
+		AuthKeyPtr temporaryKey;
+		uint64 temporaryServerSalt = 0;
+		uint64 persistentServerSalt = 0;
 	};
 	struct Delegate {
 		FnMut<void(base::expected<Result, Error>)> done;
@@ -43,11 +49,17 @@ public:
 		not_null<AbstractConnection*> connection,
 		not_null<DcOptions*> dcOptions,
 		Delegate delegate,
-		TimeId expireIn = 0); // 0 - persistent, > 0 - temporary
+		Request request);
 	~DcKeyCreator();
 
 private:
-	// Auth key creation fields and methods
+	enum class Stage {
+		None,
+		WaitingPQ,
+		WaitingDH,
+		WaitingDone,
+		Ready,
+	};
 	struct Data {
 		Data()
 		: new_nonce(*(MTPint256*)((uchar*)new_nonce_buf.data()))
@@ -61,7 +73,6 @@ private:
 		MTPint256 &new_nonce;
 		MTPlong &auth_key_aux_hash;
 
-		uint32 retries = 0;
 		MTPlong retry_id;
 
 		int32 g = 0;
@@ -69,35 +80,59 @@ private:
 		bytes::array<32> aesKey;
 		bytes::array<32> aesIV;
 		MTPlong auth_key_hash;
+		uint64 doneSalt = 0;
+	};
+	struct Attempt {
+		~Attempt();
+
+		Data data;
+		bytes::vector dhPrime;
+		bytes::vector g_a;
+		AuthKey::Data authKey = { { gsl::byte{} } };
+		TimeId expiresIn = 0;
+		uint32 retries = 0;
+		Stage stage = Stage::None;
 	};
 
-	template <typename Request>
-	void sendNotSecureRequest(const Request &request);
+	template <typename RequestType>
+	void sendNotSecureRequest(const RequestType &request);
 
-	template <typename Response>
-	[[nodiscard]] bool readNotSecureResponse(Response &response);
+	template <
+		typename RequestType,
+		typename Response = typename RequestType::ResponseType>
+	[[nodiscard]] std::optional<Response> readNotSecureResponse(
+			gsl::span<const mtpPrime> answer);
 
-	void pqSend();
-	void pqAnswered();
-	void dhParamsAnswered();
-	void dhClientParamsSend();
-	void dhClientParamsAnswered();
+	Attempt *attemptByNonce(const MTPint128 &nonce);
+
+	void answered();
+	void handleAnswer(gsl::span<const mtpPrime> answer);
+	void pqSend(not_null<Attempt*> attempt, TimeId expiresIn);
+	void pqAnswered(
+		not_null<Attempt*> attempt,
+		const MTPresPQ &data);
+	void dhParamsAnswered(
+		not_null<Attempt*> attempt,
+		const MTPserver_DH_Params &data);
+	void dhClientParamsSend(not_null<Attempt*> attempt);
+	void dhClientParamsAnswered(
+		not_null<Attempt*> attempt,
+		const MTPset_client_DH_params_answer &data);
 
 	void stopReceiving();
 	void failed(Error error = Error::Other);
-	void done(uint64 serverSalt);
+	void done();
 
 	const not_null<AbstractConnection*> _connection;
 	const not_null<DcOptions*> _dcOptions;
 	const DcId _dcId = 0;
 	const int16 _protocolDcId = 0;
-	const TimeId _expireIn = 0;
+	const Request _request;
 	Delegate _delegate;
 
-	Data _data;
-	bytes::vector _dhPrime;
-	bytes::vector _g_a;
-	AuthKey::Data _authKey = { { gsl::byte{} } };
+	Attempt _temporary;
+	Attempt _persistent;
+
 	FnMut<void(base::expected<Result, Error>)> _done;
 
 };
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 320f1b77c..0f73de8da 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -65,8 +65,9 @@ public:
 	void setMainDcId(DcId mainDcId);
 	[[nodiscard]] DcId mainDcId() const;
 
-	void dcKeyChanged(DcId dcId, const AuthKeyPtr &key);
-	[[nodiscard]] rpl::producer<DcId> dcKeyChanged() const;
+	void dcPersistentKeyChanged(DcId dcId, const AuthKeyPtr &persistentKey);
+	void dcTemporaryKeyChanged(DcId dcId);
+	[[nodiscard]] rpl::producer<DcId> dcTemporaryKeyChanged() const;
 	[[nodiscard]] AuthKeysList getKeysForWrite() const;
 	void addKeysForDestroy(AuthKeysList &&keys);
 
@@ -209,7 +210,7 @@ private:
 	bool _mainDcIdForced = false;
 	base::flat_map<DcId, std::unique_ptr<Dcenter>> _dcenters;
 	std::vector<std::unique_ptr<Dcenter>> _dcentersToDestroy;
-	rpl::event_stream<DcId> _dcKeyChanged;
+	rpl::event_stream<DcId> _dcTemporaryKeyChanged;
 
 	Session *_mainSession = nullptr;
 	base::flat_map<ShiftedDcId, std::unique_ptr<Session>> _sessions;
@@ -225,10 +226,8 @@ private:
 	crl::time _lastConfigLoadedTime = 0;
 	crl::time _configExpiresAt = 0;
 
-	std::map<DcId, AuthKeyPtr> _keysForWrite;
-	mutable QReadWriteLock _keysForWriteLock;
-
-	std::map<ShiftedDcId, mtpRequestId> _logoutGuestRequestIds;
+	base::flat_map<DcId, AuthKeyPtr> _keysForWrite;
+	base::flat_map<ShiftedDcId, mtpRequestId> _logoutGuestRequestIds;
 
 	// holds dcWithShift for request to this dc or -dc for request to main dc
 	std::map<mtpRequestId, ShiftedDcId> _requestsByDc;
@@ -619,23 +618,22 @@ void Instance::Private::logout(
 
 void Instance::Private::logoutGuestDcs() {
 	auto dcIds = std::vector<DcId>();
-	{
-		QReadLocker lock(&_keysForWriteLock);
-		dcIds.reserve(_keysForWrite.size());
-		for (auto &key : _keysForWrite) {
-			dcIds.push_back(key.first);
-		}
+	dcIds.reserve(_keysForWrite.size());
+	for (const auto &key : _keysForWrite) {
+		dcIds.push_back(key.first);
 	}
-	for (auto dcId : dcIds) {
-		if (dcId != mainDcId() && dcOptions()->dcType(dcId) != DcType::Cdn) {
-			auto shiftedDcId = MTP::logoutDcId(dcId);
-			auto requestId = _instance->send(MTPauth_LogOut(), rpcDone([this](mtpRequestId requestId) {
-				logoutGuestDone(requestId);
-			}), rpcFail([this](mtpRequestId requestId) {
-				return logoutGuestDone(requestId);
-			}), shiftedDcId);
-			_logoutGuestRequestIds.emplace(shiftedDcId, requestId);
+	for (const auto dcId : dcIds) {
+		if (dcId == mainDcId() || dcOptions()->dcType(dcId) == DcType::Cdn) {
+			continue;
 		}
+		const auto shiftedDcId = MTP::logoutDcId(dcId);
+		const auto requestId = _instance->send(MTPauth_LogOut(), rpcDone([=](
+				mtpRequestId requestId) {
+			logoutGuestDone(requestId);
+		}), rpcFail([=](mtpRequestId requestId) {
+			return logoutGuestDone(requestId);
+		}), shiftedDcId);
+		_logoutGuestRequestIds.emplace(shiftedDcId, requestId);
 	}
 }
 
@@ -695,35 +693,45 @@ not_null<Dcenter*> Instance::Private::getDcById(
 	return addDc(dcId);
 }
 
-void Instance::Private::dcKeyChanged(DcId dcId, const AuthKeyPtr &key) {
-	_dcKeyChanged.fire_copy(dcId);
+void Instance::Private::dcPersistentKeyChanged(
+		DcId dcId,
+		const AuthKeyPtr &persistentKey) {
+	dcTemporaryKeyChanged(dcId);
 
 	if (isTemporaryDcId(dcId)) {
 		return;
 	}
 
-	QWriteLocker lock(&_keysForWriteLock);
-	if (key) {
-		_keysForWrite[dcId] = key;
-	} else {
-		_keysForWrite.erase(dcId);
+	const auto i = _keysForWrite.find(dcId);
+	if (i != _keysForWrite.end() && i->second == persistentKey) {
+		return;
+	} else if (i == _keysForWrite.end() && !persistentKey) {
+		return;
 	}
-	crl::on_main(_instance, [=] {
-		DEBUG_LOG(("AuthKey Info: writing auth keys, called by dc %1").arg(dcId));
-		Local::writeMtpData();
-	});
+	if (!persistentKey) {
+		_keysForWrite.erase(i);
+	} else if (i != _keysForWrite.end()) {
+		i->second = persistentKey;
+	} else {
+		_keysForWrite.emplace(dcId, persistentKey);
+	}
+	DEBUG_LOG(("AuthKey Info: writing auth keys, called by dc %1").arg(dcId));
+	Local::writeMtpData();
 }
 
-rpl::producer<DcId> Instance::Private::dcKeyChanged() const {
-	return _dcKeyChanged.events();
+void Instance::Private::dcTemporaryKeyChanged(DcId dcId) {
+	_dcTemporaryKeyChanged.fire_copy(dcId);
+}
+
+rpl::producer<DcId> Instance::Private::dcTemporaryKeyChanged() const {
+	return _dcTemporaryKeyChanged.events();
 }
 
 AuthKeysList Instance::Private::getKeysForWrite() const {
 	auto result = AuthKeysList();
 
-	QReadLocker lock(&_keysForWriteLock);
 	result.reserve(_keysForWrite.size());
-	for (auto &key : _keysForWrite) {
+	for (const auto &key : _keysForWrite) {
 		result.push_back(key.second);
 	}
 	return result;
@@ -736,15 +744,12 @@ void Instance::Private::addKeysForDestroy(AuthKeysList &&keys) {
 		const auto dcId = key->dcId();
 		auto shiftedDcId = MTP::destroyKeyNextDcId(dcId);
 
-		{
-			QWriteLocker lock(&_keysForWriteLock);
-			// There could be several keys for one dc if we're destroying them.
-			// Place them all in separate shiftedDcId so that they won't conflict.
-			while (_keysForWrite.find(shiftedDcId) != _keysForWrite.cend()) {
-				shiftedDcId = MTP::destroyKeyNextDcId(shiftedDcId);
-			}
-			_keysForWrite[shiftedDcId] = key;
+		// There could be several keys for one dc if we're destroying them.
+		// Place them all in separate shiftedDcId so that they won't conflict.
+		while (_keysForWrite.find(shiftedDcId) != _keysForWrite.cend()) {
+			shiftedDcId = MTP::destroyKeyNextDcId(shiftedDcId);
 		}
+		_keysForWrite[shiftedDcId] = key;
 
 		addDc(shiftedDcId, std::move(key));
 		startSession(shiftedDcId);
@@ -1352,7 +1357,8 @@ bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &e
 		checkDelayedRequests();
 
 		return true;
-	} else if (code == 401 || (badGuestDc && _badGuestDcRequests.find(requestId) == _badGuestDcRequests.cend())) {
+	} else if ((code == 401 && err != "AUTH_KEY_PERM_EMPTY")
+		|| (badGuestDc && _badGuestDcRequests.find(requestId) == _badGuestDcRequests.cend())) {
 		auto dcWithShift = ShiftedDcId(0);
 		if (const auto shiftedDcId = queryRequestByDc(requestId)) {
 			dcWithShift = *shiftedDcId;
@@ -1572,10 +1578,7 @@ void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 	Expects(isKeysDestroyer());
 
 	removeDc(shiftedDcId);
-	{
-		QWriteLocker lock(&_keysForWriteLock);
-		_keysForWrite.erase(shiftedDcId);
-	}
+	_keysForWrite.erase(shiftedDcId);
 	killSession(shiftedDcId);
 	if (_dcenters.empty()) {
 		emit _instance->allKeysDestroyed();
@@ -1588,19 +1591,15 @@ void Instance::Private::checkMainDcKey() {
 	if (findSession(shiftedDcId)) {
 		return;
 	}
-	const auto key = [&] {
-		QReadLocker lock(&_keysForWriteLock);
-		const auto i = _keysForWrite.find(id);
-		return (i != end(_keysForWrite)) ? i->second : AuthKeyPtr();
-	}();
-	if (!key) {
+	const auto i = _keysForWrite.find(id);
+	if (i == end(_keysForWrite)) {
 		return;
 	}
-	const auto lastCheckTime = key->lastCheckTime();
+	const auto lastCheckTime = i->second->lastCheckTime();
 	if (lastCheckTime > 0 && lastCheckTime + kCheckKeyEach >= crl::now()) {
 		return;
 	}
-	_instance->sendDcKeyCheck(shiftedDcId, key);
+	_instance->sendDcKeyCheck(shiftedDcId, i->second);
 }
 
 void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
@@ -1608,7 +1607,7 @@ void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
 	if (const auto dc = findDc(dcId)) {
 		if (dc->destroyConfirmedForgottenKey(keyId)) {
 			LOG(("Key destroyed!"));
-			dcKeyChanged(dcId, nullptr);
+			dcPersistentKeyChanged(dcId, nullptr);
 		} else {
 			LOG(("Key already is different."));
 		}
@@ -1761,12 +1760,18 @@ void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
 	_private->logout(onDone, onFail);
 }
 
-void Instance::dcKeyChanged(DcId dcId, const AuthKeyPtr &key) {
-	_private->dcKeyChanged(dcId, key);
+void Instance::dcPersistentKeyChanged(
+		DcId dcId,
+		const AuthKeyPtr &persistentKey) {
+	_private->dcPersistentKeyChanged(dcId, persistentKey);
 }
 
-rpl::producer<DcId> Instance::dcKeyChanged() const {
-	return _private->dcKeyChanged();
+void Instance::dcTemporaryKeyChanged(DcId dcId) {
+	_private->dcTemporaryKeyChanged(dcId);
+}
+
+rpl::producer<DcId> Instance::dcTemporaryKeyChanged() const {
+	return _private->dcTemporaryKeyChanged();
 }
 
 AuthKeysList Instance::getKeysForWrite() const {
@@ -1881,13 +1886,11 @@ void Instance::sendRequest(
 }
 
 void Instance::sendAnything(ShiftedDcId shiftedDcId, crl::time msCanWait) {
-	const auto session = _private->getSession(shiftedDcId);
-	session->sendAnything(msCanWait);
+	_private->getSession(shiftedDcId)->sendAnything(msCanWait);
 }
 
 void Instance::sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key) {
-	const auto session = _private->getSession(shiftedDcId);
-	session->sendDcKeyCheck(key);
+	_private->getSession(shiftedDcId)->sendDcKeyCheck(key);
 }
 
 Instance::~Instance() {
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index bf4ddc117..dc400e8b6 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -65,8 +65,9 @@ public:
 	[[nodiscard]] QString systemVersion() const;
 
 	// Main thread.
-	void dcKeyChanged(DcId dcId, const AuthKeyPtr &key);
-	[[nodiscard]] rpl::producer<DcId> dcKeyChanged() const;
+	void dcPersistentKeyChanged(DcId dcId, const AuthKeyPtr &persistentKey);
+	void dcTemporaryKeyChanged(DcId dcId);
+	[[nodiscard]] rpl::producer<DcId> dcTemporaryKeyChanged() const;
 	[[nodiscard]] AuthKeysList getKeysForWrite() const;
 	void addKeysForDestroy(AuthKeysList &&keys);
 
diff --git a/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
index b2991a880..ef0693085 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
@@ -123,6 +123,16 @@ void AuthKey::setLastCheckTime(crl::time time) {
 	_lastCheckTime = time;
 }
 
+TimeId AuthKey::expiresAt() const {
+	return _expiresAt;
+}
+
+void AuthKey::setExpiresAt(TimeId expiresAt) {
+	Expects(_type == Type::Temporary);
+
+	_expiresAt = expiresAt;
+}
+
 void AuthKey::FillData(Data &authKey, bytes::const_span computedAuthKey) {
 	auto computedAuthKeySize = computedAuthKey.size();
 	Assert(computedAuthKeySize <= kSize);
diff --git a/Telegram/SourceFiles/mtproto/mtproto_auth_key.h b/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
index 7120cfa48..082d47310 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
+++ b/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
@@ -21,6 +21,7 @@ public:
 
 	enum class Type {
 		Generated,
+		Temporary,
 		ReadFromFile,
 		Local,
 	};
@@ -45,6 +46,8 @@ public:
 
 	[[nodiscard]] crl::time lastCheckTime() const;
 	void setLastCheckTime(crl::time time);
+	[[nodiscard]] TimeId expiresAt() const;
+	void setExpiresAt(TimeId expiresAt);
 
 	static void FillData(Data &authKey, bytes::const_span computedAuthKey);
 
@@ -56,6 +59,7 @@ private:
 	Data _key = { { gsl::byte{} } };
 	KeyId _keyId = 0;
 	crl::time _lastCheckTime = 0;
+	TimeId _expiresAt = 0;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 99feebb62..f1ee15fcb 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -7,7 +7,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/session.h"
 
-#include "mtproto/details/mtproto_dc_key_checker.h"
 #include "mtproto/connection.h"
 #include "mtproto/dcenter.h"
 #include "mtproto/mtproto_auth_key.h"
@@ -222,9 +221,14 @@ bool SessionData::connectionInited() const {
 	return _owner ? _owner->connectionInited() : false;
 }
 
-AuthKeyPtr SessionData::getKey() const {
+AuthKeyPtr SessionData::getTemporaryKey() const {
 	QMutexLocker lock(&_ownerMutex);
-	return _owner ? _owner->getKey() : nullptr;
+	return _owner ? _owner->getTemporaryKey() : nullptr;
+}
+
+AuthKeyPtr SessionData::getPersistentKey() const {
+	QMutexLocker lock(&_ownerMutex);
+	return _owner ? _owner->getPersistentKey() : nullptr;
 }
 
 bool SessionData::acquireKeyCreation() {
@@ -232,10 +236,12 @@ bool SessionData::acquireKeyCreation() {
 	return _owner ? _owner->acquireKeyCreation() : false;
 }
 
-void SessionData::releaseKeyCreationOnDone(const AuthKeyPtr &key) {
+void SessionData::releaseKeyCreationOnDone(
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKey) {
 	QMutexLocker lock(&_ownerMutex);
 	if (_owner) {
-		_owner->releaseKeyCreationOnDone(key);
+		_owner->releaseKeyCreationOnDone(temporaryKey, persistentKey);
 	}
 }
 
@@ -246,10 +252,10 @@ void SessionData::releaseKeyCreationOnFail() {
 	}
 }
 
-void SessionData::destroyCdnKey(uint64 keyId) {
+void SessionData::destroyTemporaryKey(uint64 keyId) {
 	QMutexLocker lock(&_ownerMutex);
 	if (_owner) {
-		_owner->destroyCdnKey(keyId);
+		_owner->destroyTemporaryKey(keyId);
 	}
 }
 
@@ -278,7 +284,7 @@ Session::Session(
 }
 
 void Session::watchDcKeyChanges() {
-	_instance->dcKeyChanged(
+	_instance->dcTemporaryKeyChanged(
 	) | rpl::filter([=](DcId dcId) {
 		return (dcId == _shiftedDcId) || (dcId == BareDcId(_shiftedDcId));
 	}) | rpl::start_with_next([=] {
@@ -684,6 +690,29 @@ bool Session::acquireKeyCreation() {
 	return true;
 }
 
+void Session::releaseKeyCreationOnDone(
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKey) {
+	Expects(_myKeyCreation);
+
+	DEBUG_LOG(("AuthKey Info: Session key bound, setting, dcWithShift %1"
+		).arg(_shiftedDcId));
+	_dc->releaseKeyCreationOnDone(temporaryKey, persistentKey);
+	_myKeyCreation = false;
+
+	if (sharedDc()) {
+		const auto dcId = _dc->id();
+		const auto instance = _instance;
+		InvokeQueued(instance, [=] {
+			if (persistentKey) {
+				instance->dcPersistentKeyChanged(dcId, persistentKey);
+			} else {
+				instance->dcTemporaryKeyChanged(dcId);
+			}
+		});
+	}
+}
+
 void Session::releaseKeyCreationOnFail() {
 	Expects(_myKeyCreation);
 
@@ -691,36 +720,20 @@ void Session::releaseKeyCreationOnFail() {
 	_myKeyCreation = false;
 }
 
-void Session::releaseKeyCreationOnDone(const AuthKeyPtr &key) {
-	Expects(_myKeyCreation);
-
-	DEBUG_LOG(("AuthKey Info: Session key created, setting, dcWithShift %1").arg(_shiftedDcId));
-	_dc->releaseKeyCreationOnDone(key);
-	_myKeyCreation = false;
-
-	if (sharedDc()) {
-		const auto dcId = _dc->id();
-		const auto instance = _instance;
-		InvokeQueued(instance, [=] {
-			instance->dcKeyChanged(dcId, key);
-		});
-	}
-}
-
 void Session::notifyDcConnectionInited() {
 	DEBUG_LOG(("MTP Info: emitting MTProtoDC::connectionWasInited(), dcWithShift %1").arg(_shiftedDcId));
 	_dc->setConnectionInited();
 }
 
-void Session::destroyCdnKey(uint64 keyId) {
-	if (!_dc->destroyCdnKey(keyId)) {
+void Session::destroyTemporaryKey(uint64 keyId) {
+	if (!_dc->destroyTemporaryKey(keyId)) {
 		return;
 	}
 	if (sharedDc()) {
 		const auto dcId = _dc->id();
 		const auto instance = _instance;
 		InvokeQueued(instance, [=] {
-			instance->dcKeyChanged(dcId, nullptr);
+			instance->dcTemporaryKeyChanged(dcId);
 		});
 	}
 }
@@ -729,8 +742,12 @@ int32 Session::getDcWithShift() const {
 	return _shiftedDcId;
 }
 
-AuthKeyPtr Session::getKey() const {
-	return _dc->getKey();
+AuthKeyPtr Session::getTemporaryKey() const {
+	return _dc->getTemporaryKey();
+}
+
+AuthKeyPtr Session::getPersistentKey() const {
+	return _dc->getPersistentKey();
 }
 
 bool Session::connectionInited() const {
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index a0075a214..1eb307e40 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -283,11 +283,14 @@ public:
 		bool sendMsgStateInfo);
 
 	[[nodiscard]] bool connectionInited() const;
-	[[nodiscard]] AuthKeyPtr getKey() const;
+	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
+	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
 	[[nodiscard]] bool acquireKeyCreation();
-	void releaseKeyCreationOnDone(const AuthKeyPtr &key);
+	void releaseKeyCreationOnDone(
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKey);
 	void releaseKeyCreationOnFail();
-	void destroyCdnKey(uint64 keyId);
+	void destroyTemporaryKey(uint64 keyId);
 
 	void detach();
 
@@ -351,14 +354,17 @@ public:
 
 	// Thread-safe.
 	[[nodiscard]] ShiftedDcId getDcWithShift() const;
-	[[nodiscard]] AuthKeyPtr getKey() const;
+	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
+	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
 	[[nodiscard]] bool connectionInited() const;
 
 	// Connection thread.
 	[[nodiscard]] bool acquireKeyCreation();
+	void releaseKeyCreationOnDone(
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKey);
 	void releaseKeyCreationOnFail();
-	void releaseKeyCreationOnDone(const AuthKeyPtr &key);
-	void destroyCdnKey(uint64 keyId);
+	void destroyTemporaryKey(uint64 keyId);
 
 	void notifyDcConnectionInited();
 
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index 99ec10634..83fb05965 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -34,8 +34,8 @@
       '<(src_loc)',
     ],
     'sources': [
-      '<(src_loc)/mtproto/details/mtproto_dc_key_checker.cpp',
-      '<(src_loc)/mtproto/details/mtproto_dc_key_checker.h',
+      '<(src_loc)/mtproto/details/mtproto_dc_key_binder.cpp',
+      '<(src_loc)/mtproto/details/mtproto_dc_key_binder.h',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.cpp',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.h',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.cpp',

From e7e1c9aa5af97af9e6b4c98fea66941b526a21a2 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 19 Nov 2019 14:55:39 +0300
Subject: [PATCH 31/91] Don't handle 'msg_resend_req'.

---
 Telegram/SourceFiles/mtproto/connection.cpp | 70 ++++++---------------
 Telegram/SourceFiles/mtproto/connection.h   |  6 +-
 Telegram/SourceFiles/mtproto/session.cpp    | 29 ++-------
 Telegram/SourceFiles/mtproto/session.h      |  9 +--
 4 files changed, 30 insertions(+), 84 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 64a766075..6cef04aed 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -311,6 +311,8 @@ bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 	_needSessionReset = false;
 
+	MTP_LOG(_shiftedDcId, ("Resetting session!"));
+
 	QWriteLocker locker1(_sessionData->haveSentMutex());
 	QWriteLocker locker2(_sessionData->toResendMutex());
 	QWriteLocker locker3(_sessionData->toSendMutex());
@@ -329,16 +331,10 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 
 			mtpMsgId id = i.key();
 			if (id > newId) {
-				while (true) {
-					if (toResend.constFind(newId) == toResend.cend()
-						&& wereAcked.constFind(newId) == wereAcked.cend()
-						&& haveSent.constFind(newId) == haveSent.cend()) {
-						break;
-					}
-					const auto m = base::unixtime::mtproto_msg_id();
-					if (m <= newId) break; // wtf
-
-					newId = m;
+				while (toResend.constFind(newId) != toResend.cend()
+					|| wereAcked.constFind(newId) != wereAcked.cend()
+					|| haveSent.constFind(newId) != haveSent.cend()) {
+					newId = base::unixtime::mtproto_msg_id();
 				}
 
 				MTP_LOG(_shiftedDcId, ("Replacing msgId %1 to %2!"
@@ -361,16 +357,10 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 
 			mtpMsgId id = i.key();
 			if (id > newId) {
-				while (true) {
-					if (toResend.constFind(newId) == toResend.cend()
-						&& wereAcked.constFind(newId) == wereAcked.cend()
-						&& haveSent.constFind(newId) == haveSent.cend()) {
-						break;
-					}
-					const auto m = base::unixtime::mtproto_msg_id();
-					if (m <= newId) break; // wtf
-
-					newId = m;
+				while (toResend.constFind(newId) != toResend.cend()
+					|| wereAcked.constFind(newId) != wereAcked.cend()
+					|| haveSent.constFind(newId) != haveSent.cend()) {
+					newId = base::unixtime::mtproto_msg_id();
 				}
 
 				MTP_LOG(_shiftedDcId, ("Replacing msgId %1 to %2!"
@@ -884,6 +874,7 @@ void ConnectionPrivate::tryToSend() {
 							*(toSendRequest->data() + reqNeedsLayer + 3) += initSize;
 							added = true;
 						}
+						Assert(!haveSent.contains(msgId));
 						haveSent.insert(msgId, req);
 
 						needAnyResponse = true;
@@ -900,6 +891,7 @@ void ConnectionPrivate::tryToSend() {
 			if (stateRequest) {
 				mtpMsgId msgId = placeToContainer(toSendRequest, bigMsgId, haveSentArr, stateRequest);
 				stateRequest->msDate = 0; // 0 for state request, do not request state of it
+				Assert(!haveSent.contains(msgId));
 				haveSent.insert(msgId, stateRequest);
 			}
 			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, resendRequest);
@@ -910,6 +902,7 @@ void ConnectionPrivate::tryToSend() {
 			mtpMsgId contMsgId = prepareToSend(toSendRequest, bigMsgId);
 			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = contMsgId;
 			(*haveSentIdsWrap)[6] = 0; // for container, msDate = 0, seqNo = 0
+			Assert(!haveSent.contains(contMsgId));
 			haveSent.insert(contMsgId, haveSentIdsWrap);
 			toSend.clear();
 		}
@@ -1847,24 +1840,6 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 	} return HandleResult::Success;
 
-	case mtpc_msg_resend_req: {
-		MTPMsgResendReq msg;
-		if (!msg.read(from, end)) {
-			return HandleResult::ParseError;
-		}
-		auto &ids = msg.c_msg_resend_req().vmsg_ids().v;
-
-		auto idsCount = ids.size();
-		DEBUG_LOG(("Message Info: resend of msgs requested, ids: %1").arg(LogIdsVector(ids)));
-		if (!idsCount) return (badTime ? HandleResult::Ignored : HandleResult::Success);
-
-		QVector<quint64> toResend(ids.size());
-		for (int32 i = 0, l = ids.size(); i < l; ++i) {
-			toResend[i] = ids.at(i).v;
-		}
-		resendMany(toResend, 0, false, true);
-	} return HandleResult::Success;
-
 	case mtpc_rpc_result: {
 		if (from + 3 > end) {
 			return HandleResult::ParseError;
@@ -2261,23 +2236,17 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 void ConnectionPrivate::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo) {
+		bool forceContainer) {
 	if (msgId == _pingMsgId) {
 		return;
 	}
-	_sessionData->queueResend(
-		msgId,
-		msCanWait,
-		forceContainer,
-		sendMsgStateInfo);
+	_sessionData->queueResend(msgId, msCanWait, forceContainer);
 }
 
 void ConnectionPrivate::resendMany(
 		QVector<mtpMsgId> msgIds,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo) {
+		bool forceContainer) {
 	for (int32 i = 0, l = msgIds.size(); i < l; ++i) {
 		if (msgIds.at(i) == _pingMsgId) {
 			msgIds.remove(i);
@@ -2287,8 +2256,7 @@ void ConnectionPrivate::resendMany(
 	_sessionData->queueResendMany(
 		std::move(msgIds),
 		msCanWait,
-		forceContainer,
-		sendMsgStateInfo);
+		forceContainer);
 }
 
 void ConnectionPrivate::onConnected(
@@ -2448,7 +2416,9 @@ void ConnectionPrivate::createDcKey() {
 				).arg(result->persistentServerSalt));
 
 			_sessionData->setSalt(result->temporaryServerSalt);
-			_sessionData->clearForNewKey(_instance);
+			if (result->persistentKey) {
+				_sessionData->clearForNewKey(_instance);
+			}
 
 			auto key = result->persistentKey
 				? std::move(result->persistentKey)
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index ed6950adf..1aa3ae376 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -169,13 +169,11 @@ private:
 	void resend(
 		mtpMsgId msgId,
 		crl::time msCanWait = 0,
-		bool forceContainer = false,
-		bool sendMsgStateInfo = false);
+		bool forceContainer = false);
 	void resendMany(
 		QVector<mtpMsgId> msgIds,
 		crl::time msCanWait = 0,
-		bool forceContainer = false,
-		bool sendMsgStateInfo = false);
+		bool forceContainer = false);
 
 	void createDcKey();
 	void resetSession();
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index f1ee15fcb..38f3586c8 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -193,25 +193,19 @@ void SessionData::queueSendMsgsStateInfo(quint64 msgId, QByteArray data) {
 void SessionData::queueResend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo) {
+		bool forceContainer) {
 	withSession([=](not_null<Session*> session) {
-		session->resend(msgId, msCanWait, forceContainer, sendMsgStateInfo);
+		session->resend(msgId, msCanWait, forceContainer);
 	});
 }
 
 void SessionData::queueResendMany(
 		QVector<mtpMsgId> msgIds,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo) {
+		bool forceContainer) {
 	withSession([=](not_null<Session*> session) {
 		for (const auto msgId : msgIds) {
-			session->resend(
-				msgId,
-				msCanWait,
-				forceContainer,
-				sendMsgStateInfo);
+			session->resend(msgId, msCanWait, forceContainer);
 		}
 	});
 }
@@ -595,8 +589,7 @@ QString Session::transport() const {
 mtpRequestId Session::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo) {
+		bool forceContainer) {
 	SecureRequest request;
 	{
 		QWriteLocker locker(_data->haveSentMutex());
@@ -604,18 +597,6 @@ mtpRequestId Session::resend(
 
 		auto i = haveSent.find(msgId);
 		if (i == haveSent.end()) {
-			if (sendMsgStateInfo) {
-				char cantResend[2] = {1, 0};
-				DEBUG_LOG(("Message Info: cant resend %1, request not found").arg(msgId));
-
-				auto info = std::string(cantResend, cantResend + 1);
-				return _instance->sendProtocolMessage(
-					_shiftedDcId,
-					MTPMsgsStateInfo(
-						MTP_msgs_state_info(
-							MTP_long(msgId),
-							MTP_string(std::move(info)))));
-			}
 			return 0;
 		}
 
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 1eb307e40..7432bec33 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -274,13 +274,11 @@ public:
 	void queueResend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo);
+		bool forceContainer);
 	void queueResendMany(
 		QVector<mtpMsgId> msgIds,
 		crl::time msCanWait,
-		bool forceContainer,
-		bool sendMsgStateInfo);
+		bool forceContainer);
 
 	[[nodiscard]] bool connectionInited() const;
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
@@ -392,8 +390,7 @@ public:
 	mtpRequestId resend(
 		mtpMsgId msgId,
 		crl::time msCanWait = 0,
-		bool forceContainer = false,
-		bool sendMsgStateInfo = false);
+		bool forceContainer = false);
 
 signals:
 	void authKeyChanged();

From e6d3b2b0989f70b173dbbed41ae8e8d255dff667 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 19 Nov 2019 19:14:50 +0300
Subject: [PATCH 32/91] Fix resending requests after new session.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 412 +++++++-----------
 Telegram/SourceFiles/mtproto/connection.h     |   7 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |   4 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 138 +++---
 Telegram/SourceFiles/mtproto/session.h        |  60 +--
 5 files changed, 276 insertions(+), 345 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 6cef04aed..e21f8df16 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -291,11 +291,15 @@ QString ConnectionPrivate::transport() const {
 bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 	if (ifState != Connection::UpdateAlways) {
 		QReadLocker lock(&stateConnMutex);
-		if (_state != ifState) return false;
+		if (_state != ifState) {
+			return false;
+		}
 	}
 
 	QWriteLocker lock(&stateConnMutex);
-	if (_state == state) return false;
+	if (_state == state) {
+		return false;
+	}
 	_state = state;
 	if (state < 0) {
 		_retryTimeout = -state;
@@ -308,118 +312,14 @@ bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 	return true;
 }
 
-void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
+void ConnectionPrivate::resetSession() {
+	MTP_LOG(_shiftedDcId, ("Resetting session!"));
 	_needSessionReset = false;
 
-	MTP_LOG(_shiftedDcId, ("Resetting session!"));
-
-	QWriteLocker locker1(_sessionData->haveSentMutex());
-	QWriteLocker locker2(_sessionData->toResendMutex());
-	QWriteLocker locker3(_sessionData->toSendMutex());
-	QWriteLocker locker4(_sessionData->wereAckedMutex());
-	auto &haveSent = _sessionData->haveSentMap();
-	auto &toResend = _sessionData->toResendMap();
-	auto &toSend = _sessionData->toSendMap();
-	auto &wereAcked = _sessionData->wereAckedMap();
-
-	auto newId = base::unixtime::mtproto_msg_id();
-	auto setSeqNumbers = RequestMap();
-	auto replaces = QMap<mtpMsgId, mtpMsgId>();
-	for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
-		if (!i.value().isSentContainer()) {
-			if (!*(mtpMsgId*)(i.value()->constData() + 4)) continue;
-
-			mtpMsgId id = i.key();
-			if (id > newId) {
-				while (toResend.constFind(newId) != toResend.cend()
-					|| wereAcked.constFind(newId) != wereAcked.cend()
-					|| haveSent.constFind(newId) != haveSent.cend()) {
-					newId = base::unixtime::mtproto_msg_id();
-				}
-
-				MTP_LOG(_shiftedDcId, ("Replacing msgId %1 to %2!"
-					).arg(id
-					).arg(newId));
-				replaces.insert(id, newId);
-				id = newId;
-				*(mtpMsgId*)(i.value()->data() + 4) = id;
-			}
-			setSeqNumbers.insert(id, i.value());
-		}
-	}
-	// Collect all non-container requests.
-	for (auto i = toResend.cbegin(), e = toResend.cend(); i != e; ++i) {
-		const auto j = toSend.constFind(i.value());
-		if (j == toSend.cend()) continue;
-
-		if (!j.value().isSentContainer()) {
-			if (!*(mtpMsgId*)(j.value()->constData() + 4)) continue;
-
-			mtpMsgId id = i.key();
-			if (id > newId) {
-				while (toResend.constFind(newId) != toResend.cend()
-					|| wereAcked.constFind(newId) != wereAcked.cend()
-					|| haveSent.constFind(newId) != haveSent.cend()) {
-					newId = base::unixtime::mtproto_msg_id();
-				}
-
-				MTP_LOG(_shiftedDcId, ("Replacing msgId %1 to %2!"
-					).arg(id
-					).arg(newId));
-				replaces.insert(id, newId);
-				id = newId;
-				*(mtpMsgId*)(j.value()->data() + 4) = id;
-			}
-			setSeqNumbers.insert(id, j.value());
-		}
-	}
-
-	const auto sessionId = rand_value<uint64>();
-	DEBUG_LOG(("MTP Info: creating new session after bad_msg_notification, setting random server_session %1").arg(sessionId));
-	_sessionData->setSessionId(sessionId);
-
-	for (auto i = setSeqNumbers.cbegin(), e = setSeqNumbers.cend(); i != e; ++i) { // generate new seq_numbers
-		bool wasNeedAck = (*(i.value()->data() + 6) & 1);
-		*(i.value()->data() + 6) = _sessionData->nextRequestSeqNumber(wasNeedAck);
-	}
-	if (!replaces.isEmpty()) {
-		for (auto i = replaces.cbegin(), e = replaces.cend(); i != e; ++i) { // replace msgIds keys in all data structs
-			const auto j = haveSent.find(i.key());
-			if (j != haveSent.cend()) {
-				const auto req = j.value();
-				haveSent.erase(j);
-				haveSent.insert(i.value(), req);
-			}
-			const auto k = toResend.find(i.key());
-			if (k != toResend.cend()) {
-				const auto req = k.value();
-				toResend.erase(k);
-				toResend.insert(i.value(), req);
-			}
-			const auto l = wereAcked.find(i.key());
-			if (l != wereAcked.cend()) {
-				DEBUG_LOG(("MTP Info: Replaced %1 with %2 in wereAcked."
-					).arg(i.key()
-					).arg(i.value()));
-
-				const auto req = l.value();
-				wereAcked.erase(l);
-				wereAcked.insert(i.value(), req);
-			}
-		}
-		for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) { // replace msgIds in saved containers
-			if (i.value().isSentContainer()) {
-				mtpMsgId *ids = (mtpMsgId*)(i.value()->data() + 8);
-				for (uint32 j = 0, l = (i.value()->size() - 8) >> 1; j < l; ++j) {
-					const auto k = replaces.constFind(ids[j]);
-					if (k != replaces.cend()) {
-						ids[j] = k.value();
-					}
-				}
-			}
-		}
-	}
+	DEBUG_LOG(("MTP Info: creating new session in resetSession."));
+	_sessionData->changeSessionId();
 
+	// #TODO move to sessionData, clear on changeSessionIdLocked.
 	_ackRequestData.clear();
 	_resendRequestData.clear();
 	{
@@ -432,93 +332,99 @@ void ConnectionPrivate::resetSession() { // recreate all msg_id and msg_seqno
 
 mtpMsgId ConnectionPrivate::prepareToSend(
 		SecureRequest &request,
-		mtpMsgId currentLastId) {
-	if (request->size() < 9) {
-		return 0;
-	}
+		mtpMsgId currentLastId,
+		bool forceNewMsgId) {
+	Expects(request->size() > 8);
+
 	if (const auto msgId = request.getMsgId()) {
 		// resending this request
-		QWriteLocker locker(_sessionData->toResendMutex());
+		QWriteLocker lock(_sessionData->toResendMutex());
 		auto &toResend = _sessionData->toResendMap();
 		const auto i = toResend.find(msgId);
 		if (i != toResend.cend()) {
 			toResend.erase(i);
 		}
-		return msgId;
+		lock.unlock();
+
+		return (forceNewMsgId || msgId > currentLastId)
+			? replaceMsgId(request, currentLastId)
+			: msgId;
 	}
 	request.setMsgId(currentLastId);
 	request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
+	if (request->requestId) {
+		MTP_LOG(_shiftedDcId, ("[r%1] msg_id 0 -> %2").arg(request->requestId).arg(currentLastId));
+	}
 	return currentLastId;
 }
 
 mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId) {
-	if (request->size() < 9) return 0;
+	Expects(request->size() > 8);
 
 	const auto oldMsgId = request.getMsgId();
-	if (oldMsgId != newId) {
-		if (oldMsgId) {
-			QWriteLocker locker(_sessionData->toResendMutex());
-			// haveSentMutex() and wereAckedMutex() were locked in tryToSend()
-
-			auto &toResend = _sessionData->toResendMap();
-			auto &wereAcked = _sessionData->wereAckedMap();
-			auto &haveSent = _sessionData->haveSentMap();
-
-			while (true) {
-				if (toResend.constFind(newId) == toResend.cend() && wereAcked.constFind(newId) == wereAcked.cend() && haveSent.constFind(newId) == haveSent.cend()) {
-					break;
-				}
-				const auto m = base::unixtime::mtproto_msg_id();
-				if (m <= newId) break; // wtf
-
-				newId = m;
-			}
-
-			const auto i = toResend.find(oldMsgId);
-			if (i != toResend.cend()) {
-				const auto req = i.value();
-				toResend.erase(i);
-				toResend.insert(newId, req);
-			}
-
-			const auto j = wereAcked.find(oldMsgId);
-			if (j != wereAcked.cend()) {
-				const auto req = j.value();
-				wereAcked.erase(j);
-				wereAcked.insert(newId, req);
-			}
-
-			const auto k = haveSent.find(oldMsgId);
-			if (k != haveSent.cend()) {
-				const auto req = k.value();
-				haveSent.erase(k);
-				haveSent.insert(newId, req);
-			}
-
-			for (auto l = haveSent.begin(); l != haveSent.cend(); ++l) {
-				const auto req = l.value();
-				if (req.isSentContainer()) {
-					const auto ids = (mtpMsgId *)(req->data() + 8);
-					for (uint32 i = 0, l = (req->size() - 8) >> 1; i < l; ++i) {
-						if (ids[i] == oldMsgId) {
-							ids[i] = newId;
-						}
-					}
-				}
-			}
-		} else {
-			request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
-		}
-		request.setMsgId(newId);
+	if (oldMsgId == newId) {
+		return newId;
 	}
+	QWriteLocker locker(_sessionData->toResendMutex());
+	// haveSentMutex() and wereAckedMutex() were locked in tryToSend()
+
+	auto &toResend = _sessionData->toResendMap();
+	auto &wereAcked = _sessionData->wereAckedMap();
+	auto &haveSent = _sessionData->haveSentMap();
+
+	while (toResend.constFind(newId) != toResend.cend()
+		|| wereAcked.constFind(newId) != wereAcked.cend()
+		|| haveSent.constFind(newId) != haveSent.cend()) {
+		newId = base::unixtime::mtproto_msg_id();
+	}
+
+	MTP_LOG(_shiftedDcId, ("[r%1] msg_id %2 -> %3").arg(request->requestId).arg(oldMsgId).arg(newId));
+
+	const auto i = toResend.find(oldMsgId);
+	if (i != toResend.cend()) {
+		const auto req = i.value();
+		toResend.erase(i);
+		toResend.insert(newId, req);
+	}
+
+	const auto j = wereAcked.find(oldMsgId);
+	if (j != wereAcked.cend()) {
+		const auto req = j.value();
+		wereAcked.erase(j);
+		wereAcked.insert(newId, req);
+	}
+
+	const auto k = haveSent.find(oldMsgId);
+	if (k != haveSent.cend()) {
+		const auto req = k.value();
+		haveSent.erase(k);
+		haveSent.insert(newId, req);
+	}
+
+	for (auto l = haveSent.begin(); l != haveSent.cend(); ++l) {
+		const auto req = l.value();
+		if (req.isSentContainer()) {
+			const auto ids = (mtpMsgId *)(req->data() + 8);
+			for (uint32 i = 0, l = (req->size() - 8) >> 1; i < l; ++i) {
+				if (ids[i] == oldMsgId) {
+					ids[i] = newId;
+				}
+			}
+		}
+	}
+
+	request.setMsgId(newId);
+	request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
 	return newId;
 }
 
-mtpMsgId ConnectionPrivate::placeToContainer(SecureRequest &toSendRequest, mtpMsgId &bigMsgId, mtpMsgId *&haveSentArr, SecureRequest &req) {
-	auto msgId = prepareToSend(req, bigMsgId);
-	if (msgId > bigMsgId) {
-		msgId = replaceMsgId(req, bigMsgId);
-	}
+mtpMsgId ConnectionPrivate::placeToContainer(
+		SecureRequest &toSendRequest,
+		mtpMsgId &bigMsgId,
+		bool forceNewMsgId,
+		mtpMsgId *&haveSentArr,
+		SecureRequest &req) {
+	const auto msgId = prepareToSend(req, bigMsgId, forceNewMsgId);
 	if (msgId >= bigMsgId) {
 		bigMsgId = base::unixtime::mtproto_msg_id();
 	}
@@ -551,7 +457,12 @@ void ConnectionPrivate::tryToSend() {
 		&& _pingSendAt <= crl::now()) {
 		_pingIdToSend = openssl::RandomValue<mtpPingId>();
 	}
+	const auto forceNewMsgId = sendAll
+		&& _sessionData->markSessionAsStarted();
 
+	if (forceNewMsgId) {
+		int a = 0;
+	}
 	auto pingRequest = SecureRequest();
 	auto ackRequest = SecureRequest();
 	auto resendRequest = SecureRequest();
@@ -744,7 +655,8 @@ void ConnectionPrivate::tryToSend() {
 
 			const auto msgId = prepareToSend(
 				toSendRequest,
-				base::unixtime::mtproto_msg_id());
+				base::unixtime::mtproto_msg_id(),
+				forceNewMsgId);
 			if (pingRequest) {
 				_pingMsgId = msgId;
 				needAnyResponse = true;
@@ -839,17 +751,22 @@ void ConnectionPrivate::tryToSend() {
 			auto haveSentArr = (mtpMsgId*)(haveSentIdsWrap->data() + 8);
 
 			if (pingRequest) {
-				_pingMsgId = placeToContainer(toSendRequest, bigMsgId, haveSentArr, pingRequest);
+				_pingMsgId = placeToContainer(
+					toSendRequest,
+					bigMsgId,
+					forceNewMsgId,
+					haveSentArr,
+					pingRequest);
 				needAnyResponse = true;
 			} else if (resendRequest || stateRequest || bindDcKeyRequest) {
 				needAnyResponse = true;
 			}
 			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
 				auto &req = i.value();
-				auto msgId = prepareToSend(req, bigMsgId);
-				if (msgId > bigMsgId) {
-					msgId = replaceMsgId(req, bigMsgId);
-				}
+				const auto msgId = prepareToSend(
+					req,
+					bigMsgId,
+					forceNewMsgId);
 				if (msgId >= bigMsgId) {
 					bigMsgId = base::unixtime::mtproto_msg_id();
 				}
@@ -889,21 +806,24 @@ void ConnectionPrivate::tryToSend() {
 				}
 			}
 			if (stateRequest) {
-				mtpMsgId msgId = placeToContainer(toSendRequest, bigMsgId, haveSentArr, stateRequest);
+				mtpMsgId msgId = placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, stateRequest);
 				stateRequest->msDate = 0; // 0 for state request, do not request state of it
 				Assert(!haveSent.contains(msgId));
 				haveSent.insert(msgId, stateRequest);
 			}
-			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, resendRequest);
-			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, ackRequest);
-			if (httpWaitRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, httpWaitRequest);
-			if (bindDcKeyRequest) placeToContainer(toSendRequest, bigMsgId, haveSentArr, bindDcKeyRequest);
+			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, resendRequest);
+			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, ackRequest);
+			if (httpWaitRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, httpWaitRequest);
+			if (bindDcKeyRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, bindDcKeyRequest);
 
-			mtpMsgId contMsgId = prepareToSend(toSendRequest, bigMsgId);
-			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = contMsgId;
+			const auto containerMsgId = prepareToSend(
+				toSendRequest,
+				bigMsgId,
+				forceNewMsgId);
+			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = containerMsgId;
 			(*haveSentIdsWrap)[6] = 0; // for container, msDate = 0, seqNo = 0
-			Assert(!haveSent.contains(contMsgId));
-			haveSent.insert(contMsgId, haveSentIdsWrap);
+			Assert(!haveSent.contains(containerMsgId));
+			haveSent.insert(containerMsgId, haveSentIdsWrap);
 			toSend.clear();
 		}
 	}
@@ -1050,7 +970,6 @@ void ConnectionPrivate::restart() {
 	if (_needSessionReset) {
 		resetSession();
 	}
-	_restarted = true;
 	if (_retryTimer.isActive()) {
 		return;
 	}
@@ -1144,7 +1063,6 @@ void ConnectionPrivate::waitReceivedFailed() {
 		_waitForReceived *= 2;
 	}
 	doDisconnect();
-	_restarted = true;
 	if (_retryTimer.isActive()) {
 		return;
 	}
@@ -1164,7 +1082,6 @@ void ConnectionPrivate::waitConnectedFailed() {
 	}
 
 	connectingTimedOut();
-	_restarted = true;
 
 	DEBUG_LOG(("MTP Info: immediate restart!"));
 	InvokeQueued(this, [=] { connectToServer(); });
@@ -1183,9 +1100,7 @@ void ConnectionPrivate::connectingTimedOut() {
 
 void ConnectionPrivate::doDisconnect() {
 	destroyAllConnections();
-
 	setState(DisconnectedState);
-	_restarted = false;
 }
 
 void ConnectionPrivate::finishAndDestroy() {
@@ -1212,6 +1127,8 @@ void ConnectionPrivate::requestCDNConfig() {
 }
 
 void ConnectionPrivate::handleReceived() {
+	Expects(_temporaryKey != nullptr);
+
 	onReceivedSome();
 
 	while (!_connection->received().empty()) {
@@ -1345,9 +1262,8 @@ void ConnectionPrivate::handleReceived() {
 				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2, updating...").arg(serverSalt).arg(mySalt));
 				_sessionData->setSalt(serverSalt);
 
-				if (setState(ConnectedState, ConnectingState) && _restarted) {
-					_sessionData->queueResendAll();
-					_restarted = false;
+				if (setState(ConnectedState, ConnectingState)) {
+					_sessionData->resendAll();
 				}
 			} else {
 				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2").arg(serverSalt).arg(mySalt));
@@ -1393,9 +1309,10 @@ void ConnectionPrivate::handleReceived() {
 		}
 
 		if (res != HandleResult::Success && res != HandleResult::Ignored) {
-			_needSessionReset = (res == HandleResult::ResetSession);
 			if (res == HandleResult::DestroyTemporaryKey) {
 				destroyTemporaryKey();
+			} else if (res == HandleResult::ResetSession) {
+				_needSessionReset = true;
 			}
 			return restart();
 		}
@@ -1633,11 +1550,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		_sessionData->setSalt(serverSalt);
 		base::unixtime::update(serverTime);
 
-		if (setState(ConnectedState, ConnectingState)) { // maybe only connected
-			if (_restarted) {
-				_sessionData->queueResendAll();
-				_restarted = false;
-			}
+		if (setState(ConnectedState, ConnectingState)) {
+			_sessionData->resendAll();
 		}
 
 		badTime = false;
@@ -1863,7 +1777,6 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				return HandleResult::Ignored;
 			}
 		}
-		requestsAcked(ids, true);
 
 		if (typeId == mtpc_gzip_packed) {
 			DEBUG_LOG(("RPC Info: gzip container"));
@@ -1880,12 +1793,13 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			if (DcKeyBinder::IsDestroyedTemporaryKeyError(response)) {
 				return HandleResult::DestroyTemporaryKey;
 			}
-		} else {
 			// An error could be some RPC_CALL_FAIL or other error inside
 			// the initConnection, so we're not sure yet that it was inited.
 			// Wait till a good response is received.
+		} else {
 			_sessionData->notifyConnectionInited(*_connectionOptions);
 		}
+		requestsAcked(ids, true);
 
 		if (_keyBinder) {
 			const auto result = _keyBinder->handleResponse(
@@ -1945,11 +1859,16 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			const auto &haveSent = _sessionData->haveSentMap();
 			toResend.reserve(haveSent.size());
 			for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
-				if (i.key() >= firstMsgId) break;
-				if (i.value()->requestId) toResend.push_back(i.key());
+				if (i.key() >= firstMsgId) {
+					break;
+				} else if (i.value()->requestId) {
+					toResend.push_back(i.key());
+				}
 			}
 		}
-		resendMany(toResend, 10, true);
+		for (const auto msgId : toResend) {
+			_sessionData->resend(msgId, 10, true);
+		}
 
 		mtpBuffer update(from - start);
 		if (from > start) memcpy(update.data(), start, (from - start) * sizeof(mtpPrime));
@@ -2237,26 +2156,18 @@ void ConnectionPrivate::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
 		bool forceContainer) {
-	if (msgId == _pingMsgId) {
-		return;
+	if (msgId != _pingMsgId) {
+		_sessionData->resend(msgId, msCanWait, forceContainer);
 	}
-	_sessionData->queueResend(msgId, msCanWait, forceContainer);
 }
 
 void ConnectionPrivate::resendMany(
 		QVector<mtpMsgId> msgIds,
 		crl::time msCanWait,
 		bool forceContainer) {
-	for (int32 i = 0, l = msgIds.size(); i < l; ++i) {
-		if (msgIds.at(i) == _pingMsgId) {
-			msgIds.remove(i);
-			--l;
-		}
+	for (const auto msgId : msgIds) {
+		resend(msgId, msCanWait, forceContainer);
 	}
-	_sessionData->queueResendMany(
-		std::move(msgIds),
-		msCanWait,
-		forceContainer);
 }
 
 void ConnectionPrivate::onConnected(
@@ -2340,10 +2251,13 @@ void ConnectionPrivate::removeTestConnection(
 }
 
 void ConnectionPrivate::checkAuthKey() {
-	if (!_keyId) {
-		updateAuthKey();
-	} else {
+	Expects(_keyCreator == nullptr);
+	Expects(_keyBinder == nullptr || _keyId != 0);
+
+	if (_keyId) {
 		authKeyChecked();
+	} else {
+		applyAuthKey(_sessionData->getTemporaryKey());
 	}
 }
 
@@ -2359,23 +2273,40 @@ void ConnectionPrivate::updateAuthKey() {
 void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
 	_temporaryKey = std::move(temporaryKey);
 	const auto newKeyId = _temporaryKey ? _temporaryKey->keyId() : 0;
-	if (newKeyId) {
+	if (_keyId) {
 		if (_keyId == newKeyId) {
 			return;
 		}
-		_sessionData->setCurrentKeyId(newKeyId);
+		_keyId = 0;
+		if (_sessionData->setCurrentKeyId(_keyId)) {
+			_ackRequestData.clear(); // #TODO move to sessionData.
+			_resendRequestData.clear();
+			{
+				QWriteLocker locker5(_sessionData->stateRequestMutex());
+				_sessionData->stateRequestMap().clear();
+			}
+		}
+		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed, restarting..."
+			).arg(_shiftedDcId));
+		if (_connection) {
+			restart();
+		}
+		return;
 	}
-	_keyId = newKeyId;
 	if (!_connection) {
 		return;
 	}
-	if (const auto already = _connection->sentEncryptedWithKeyId()) {
-		Assert(already != newKeyId);
-		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
-
-		restart();
-		return;
+	if (newKeyId && _sessionData->setCurrentKeyId(newKeyId)) {
+		_ackRequestData.clear(); // #TODO move to sessionData.
+		_resendRequestData.clear();
+		{
+			QWriteLocker locker5(_sessionData->stateRequestMutex());
+			_sessionData->stateRequestMap().clear();
+		}
 	}
+	_keyId = newKeyId;
+	Assert(!_connection->sentEncryptedWithKeyId());
+
 	DEBUG_LOG(("AuthKey Info: Connection update key from Session, dc %1 result: %2").arg(_shiftedDcId).arg(Logs::mb(&_keyId, sizeof(_keyId)).str()));
 	if (_keyId) {
 		return authKeyChecked();
@@ -2470,12 +2401,8 @@ void ConnectionPrivate::authKeyChecked() {
 		handleReceived();
 	});
 
-	if (_sessionData->getSalt()) {
-		setState(ConnectedState);
-		if (_restarted) {
-			_sessionData->queueResendAll();
-			_restarted = false;
-		}
+	if (_sessionData->getSalt() && setState(ConnectedState)) {
+		_sessionData->resendAll();
 	} // else receive salt in bad_server_salt first, then try to send all the requests
 
 	_pingIdToSend = rand_value<uint64>(); // get server_salt
@@ -2525,7 +2452,6 @@ void ConnectionPrivate::destroyTemporaryKey() {
 	if (_temporaryKey) {
 		_sessionData->destroyTemporaryKey(_temporaryKey->keyId());
 	}
-	_needSessionReset = true;
 	applyAuthKey(nullptr);
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 1aa3ae376..d786f80ea 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -139,9 +139,13 @@ private:
 	mtpMsgId placeToContainer(
 		SecureRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
+		bool forceNewMsgId,
 		mtpMsgId *&haveSentArr,
 		SecureRequest &req);
-	mtpMsgId prepareToSend(SecureRequest &request, mtpMsgId currentLastId);
+	mtpMsgId prepareToSend(
+		SecureRequest &request,
+		mtpMsgId currentLastId,
+		bool forceNewMsgId);
 	mtpMsgId replaceMsgId(SecureRequest &request, mtpMsgId newId);
 
 	bool sendSecureRequest(SecureRequest &&request, bool needAnyResponse);
@@ -221,7 +225,6 @@ private:
 	mtpMsgId _pingMsgId = 0;
 	base::Timer _pingSender;
 
-	bool _restarted = false;
 	bool _finished = false;
 
 	AuthKeyPtr _temporaryKey;
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 0f73de8da..f4c0a22e9 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -1156,7 +1156,9 @@ void Instance::Private::onSessionReset(ShiftedDcId dcWithShift) {
 
 bool Instance::Private::rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err) { // return true if need to clean request data
 	if (isDefaultHandledError(err)) {
-		if (onFail && (*onFail)(requestId, err)) return true;
+		if (onFail && (*onFail)(requestId, err)) {
+			return true;
+		}
 	}
 
 	if (onErrorDefault(requestId, err)) {
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 38f3586c8..0504cb045 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -26,10 +26,6 @@ constexpr auto kCheckResendTimeout = crl::time(10000);
 // when resending request or checking its state.
 constexpr auto kCheckResendWaiting = crl::time(1000);
 
-// How much ints should message contain for us not to resend,
-// but instead to check its state.
-constexpr auto kResendThreshold = 1;
-
 // Container lives 10 minutes in haveSent map.
 constexpr auto kContainerLives = 600;
 
@@ -76,15 +72,51 @@ void SessionData::withSession(Callback &&callback) {
 	}
 }
 
-void SessionData::setCurrentKeyId(uint64 keyId) {
+bool SessionData::setCurrentKeyId(uint64 keyId) {
 	QWriteLocker locker(&_lock);
 	if (_keyId == keyId) {
-		return;
+		return false;
 	}
 	_keyId = keyId;
-	_sessionId = openssl::RandomValue<uint64>();
+
+	DEBUG_LOG(("MTP Info: auth key set in SessionData, id %1").arg(keyId));
+
+	changeSessionIdLocked();
+	return true;
+}
+
+void SessionData::changeSessionId() {
+	QWriteLocker locker(&_lock);
+	changeSessionIdLocked();
+}
+
+void SessionData::changeSessionIdLocked() {
+	auto sessionId = _sessionId;
+	do {
+		sessionId = openssl::RandomValue<uint64>();
+	} while (_sessionId == sessionId);
+
+	DEBUG_LOG(("MTP Info: setting server_session: %1").arg(sessionId));
+
+	_sessionId = sessionId;
 	_messagesSent = 0;
-	DEBUG_LOG(("MTP Info: new auth key set in SessionData, id %1, setting random server_session %2").arg(_keyId).arg(_sessionId));
+	_sessionMarkedAsStarted = false;
+}
+
+uint32 SessionData::nextRequestSeqNumber(bool needAck) {
+	QWriteLocker locker(&_lock);
+	auto result = _messagesSent;
+	_messagesSent += (needAck ? 1 : 0);
+	return result * 2 + (needAck ? 1 : 0);
+}
+
+bool SessionData::markSessionAsStarted() {
+	QWriteLocker locker(&_lock);
+	if (_sessionMarkedAsStarted) {
+		return false;
+	}
+	_sessionMarkedAsStarted = true;
+	return true;
 }
 
 void SessionData::setKeyForCheck(const AuthKeyPtr &key) {
@@ -166,12 +198,6 @@ void SessionData::queueConnectionStateChange(int newState) {
 	});
 }
 
-void SessionData::queueResendAll() {
-	withSession([](not_null<Session*> session) {
-		session->resendAll();
-	});
-}
-
 void SessionData::queueResetDone() {
 	withSession([](not_null<Session*> session) {
 		session->resetDone();
@@ -190,24 +216,21 @@ void SessionData::queueSendMsgsStateInfo(quint64 msgId, QByteArray data) {
 	});
 }
 
-void SessionData::queueResend(
+void SessionData::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
 		bool forceContainer) {
-	withSession([=](not_null<Session*> session) {
-		session->resend(msgId, msCanWait, forceContainer);
-	});
+	QMutexLocker lock(&_ownerMutex);
+	if (_owner) {
+		_owner->resend(msgId, msCanWait, forceContainer);
+	}
 }
 
-void SessionData::queueResendMany(
-		QVector<mtpMsgId> msgIds,
-		crl::time msCanWait,
-		bool forceContainer) {
-	withSession([=](not_null<Session*> session) {
-		for (const auto msgId : msgIds) {
-			session->resend(msgId, msCanWait, forceContainer);
-		}
-	});
+void SessionData::resendAll() {
+	QMutexLocker lock(&_ownerMutex);
+	if (_owner) {
+		_owner->resendAll();
+	}
 }
 
 bool SessionData::connectionInited() const {
@@ -437,7 +460,6 @@ bool Session::sharedDc() const {
 }
 
 void Session::checkRequestsByTimer() {
-	QVector<mtpMsgId> resendingIds;
 	QVector<mtpMsgId> removingIds; // remove very old (10 minutes) containers and resend requests
 	QVector<mtpMsgId> stateRequestIds;
 
@@ -450,14 +472,9 @@ void Session::checkRequestsByTimer() {
 			auto &req = i.value();
 			if (req->msDate > 0) {
 				if (req->msDate + kCheckResendTimeout < ms) { // need to resend or check state
-					if (req.messageSize() < kResendThreshold) { // resend
-						resendingIds.reserve(haveSentCount);
-						resendingIds.push_back(i.key());
-					} else {
-						req->msDate = ms;
-						stateRequestIds.reserve(haveSentCount);
-						stateRequestIds.push_back(i.key());
-					}
+					req->msDate = ms;
+					stateRequestIds.reserve(haveSentCount);
+					stateRequestIds.push_back(i.key());
 				}
 			} else if (base::unixtime::now()
 					> int32(i.key() >> 32) + kContainerLives) {
@@ -477,12 +494,6 @@ void Session::checkRequestsByTimer() {
 		}
 		sendAnything(kCheckResendWaiting);
 	}
-	if (!resendingIds.isEmpty()) {
-		for (uint32 i = 0, l = resendingIds.size(); i < l; ++i) {
-			DEBUG_LOG(("MTP Info: resending request %1").arg(resendingIds[i]));
-			resend(resendingIds[i], kCheckResendWaiting);
-		}
-	}
 	if (!removingIds.isEmpty()) {
 		auto clearCallbacks = std::vector<RPCCallbackClear>();
 		{
@@ -586,40 +597,35 @@ QString Session::transport() const {
 	return _connection ? _connection->transport() : QString();
 }
 
-mtpRequestId Session::resend(
+void Session::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
 		bool forceContainer) {
-	SecureRequest request;
-	{
-		QWriteLocker locker(_data->haveSentMutex());
-		auto &haveSent = _data->haveSentMap();
+	auto lock = QWriteLocker(_data->haveSentMutex());
+	auto &haveSent = _data->haveSentMap();
 
-		auto i = haveSent.find(msgId);
-		if (i == haveSent.end()) {
-			return 0;
-		}
-
-		request = i.value();
-		haveSent.erase(i);
+	auto i = haveSent.find(msgId);
+	if (i == haveSent.end()) {
+		return;
 	}
-	if (request.isSentContainer()) { // for container just resend all messages we can
+	auto request = i.value();
+	haveSent.erase(i);
+	lock.unlock();
+
+	// For container just resend all messages we can.
+	if (request.isSentContainer()) {
 		DEBUG_LOG(("Message Info: resending container from haveSent, msgId %1").arg(msgId));
 		const mtpMsgId *ids = (const mtpMsgId *)(request->constData() + 8);
 		for (uint32 i = 0, l = (request->size() - 8) >> 1; i < l; ++i) {
 			resend(ids[i], 10, true);
 		}
-		return 0xFFFFFFFF;
 	} else if (!request.isStateRequest()) {
 		request->msDate = forceContainer ? 0 : crl::now();
-		sendPrepared(request, msCanWait, false);
 		{
 			QWriteLocker locker(_data->toResendMutex());
 			_data->toResendMap().insert(msgId, request->requestId);
 		}
-		return request->requestId;
-	} else {
-		return 0;
+		sendPrepared(request, msCanWait, false);
 	}
 }
 
@@ -636,8 +642,11 @@ void Session::resendAll() {
 		}
 	}
 	for (uint32 i = 0, l = toResend.size(); i < l; ++i) {
-		resend(toResend[i], 10, true);
+		resend(toResend[i], -1, true);
 	}
+	InvokeQueued(this, [=] {
+		sendAnything();
+	});
 }
 
 void Session::sendPrepared(
@@ -657,8 +666,11 @@ void Session::sendPrepared(
 	}
 
 	DEBUG_LOG(("MTP Info: added, requestId %1").arg(request->requestId));
-
-	sendAnything(msCanWait);
+	if (msCanWait >= 0) {
+		InvokeQueued(this, [=] {
+			sendAnything(msCanWait);
+		});
+	}
 }
 
 bool Session::acquireKeyCreation() {
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 7432bec33..b3034dcc8 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -140,16 +140,8 @@ public:
 	SessionData(not_null<Session*> creator) : _owner(creator) {
 	}
 
-	void setCurrentKeyId(uint64 keyId);
-	void setSessionId(uint64 sessionId) {
-		DEBUG_LOG(("MTP Info: setting server_session: %1").arg(sessionId));
-
-		QWriteLocker locker(&_lock);
-		if (_sessionId != sessionId) {
-			_sessionId = sessionId;
-			_messagesSent = 0;
-		}
-	}
+	bool setCurrentKeyId(uint64 keyId);
+	void changeSessionId();
 	[[nodiscard]] uint64 getSessionId() const {
 		QReadLocker locker(&_lock);
 		return _sessionId;
@@ -254,12 +246,8 @@ public:
 		return _owner;
 	}
 
-	uint32 nextRequestSeqNumber(bool needAck = true) {
-		QWriteLocker locker(&_lock);
-		auto result = _messagesSent;
-		_messagesSent += (needAck ? 1 : 0);
-		return result * 2 + (needAck ? 1 : 0);
-	}
+	[[nodiscard]] bool markSessionAsStarted();
+	[[nodiscard]] uint32 nextRequestSeqNumber(bool needAck);
 
 	void clearForNewKey(not_null<Instance*> instance);
 
@@ -267,18 +255,9 @@ public:
 	void queueTryToReceive();
 	void queueNeedToResumeAndSend();
 	void queueConnectionStateChange(int newState);
-	void queueResendAll();
 	void queueResetDone();
 	void queueSendAnything(crl::time msCanWait = 0);
 	void queueSendMsgsStateInfo(quint64 msgId, QByteArray data);
-	void queueResend(
-		mtpMsgId msgId,
-		crl::time msCanWait,
-		bool forceContainer);
-	void queueResendMany(
-		QVector<mtpMsgId> msgIds,
-		crl::time msCanWait,
-		bool forceContainer);
 
 	[[nodiscard]] bool connectionInited() const;
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
@@ -289,10 +268,17 @@ public:
 		const AuthKeyPtr &persistentKey);
 	void releaseKeyCreationOnFail();
 	void destroyTemporaryKey(uint64 keyId);
+	void resend(
+		mtpMsgId msgId,
+		crl::time msCanWait,
+		bool forceContainer);
+	void resendAll();
 
 	void detach();
 
 private:
+	void changeSessionIdLocked();
+
 	template <typename Callback>
 	void withSession(Callback &&callback);
 
@@ -300,6 +286,7 @@ private:
 	uint64 _sessionId = 0;
 	uint64 _salt = 0;
 	uint32 _messagesSent = 0;
+	bool _sessionMarkedAsStarted = false;
 
 	Session *_owner = nullptr;
 	mutable QMutex _ownerMutex;
@@ -355,6 +342,18 @@ public:
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
 	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
 	[[nodiscard]] bool connectionInited() const;
+	void resend(
+		mtpMsgId msgId,
+		crl::time msCanWait = 0,
+		bool forceContainer = false);
+	void resendAll();
+
+	// Thread-safe.
+	// Nulls msgId and seqNo in request, if newRequest = true.
+	void sendPrepared(
+		const SecureRequest &request,
+		crl::time msCanWait = 0,
+		bool newRequest = true);
 
 	// Connection thread.
 	[[nodiscard]] bool acquireKeyCreation();
@@ -374,23 +373,12 @@ public:
 
 	void sendDcKeyCheck(const AuthKeyPtr &key);
 
-	// Nulls msgId and seqNo in request, if newRequest = true.
-	void sendPrepared(
-		const SecureRequest &request,
-		crl::time msCanWait = 0,
-		bool newRequest = true);
-
 	void tryToReceive();
 	void needToResumeAndSend();
 	void connectionStateChange(int newState);
-	void resendAll(); // After connection restart.
 	void resetDone();
 	void sendAnything(crl::time msCanWait = 0);
 	void sendMsgsStateInfo(quint64 msgId, QByteArray data);
-	mtpRequestId resend(
-		mtpMsgId msgId,
-		crl::time msCanWait = 0,
-		bool forceContainer = false);
 
 signals:
 	void authKeyChanged();

From f424cb54f7c1c2f4f5d92d87fa93ff5d0e51f2d3 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 19 Nov 2019 19:22:02 +0300
Subject: [PATCH 33/91] Create keys not simultaneously.

---
 .../mtproto/details/mtproto_dc_key_creator.cpp       | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index 71f12b2ca..bf8fac938 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -183,9 +183,10 @@ DcKeyCreator::DcKeyCreator(
 		answered();
 	});
 
-	pqSend(&_temporary, _request.temporaryExpiresIn);
 	if (_request.persistentNeeded) {
 		pqSend(&_persistent, 0);
+	} else {
+		pqSend(&_temporary, _request.temporaryExpiresIn);
 	}
 }
 
@@ -602,13 +603,12 @@ void DcKeyCreator::failed(Error error) {
 }
 
 void DcKeyCreator::done() {
-	Expects(_temporary.stage != Stage::None);
-
-	if (_persistent.stage != Stage::None && _persistent.stage != Stage::Ready) {
-		return;
-	} else if (_temporary.stage != Stage::Ready) {
+	if (_temporary.stage == Stage::None) {
+		pqSend(&_temporary, _request.temporaryExpiresIn);
 		return;
 	}
+	Assert(_temporary.stage == Stage::Ready);
+	Assert(_persistent.stage == Stage::Ready || _persistent.stage == Stage::None);
 
 	auto result = Result();
 	result.temporaryKey = std::make_shared<AuthKey>(

From 43bab3eeaaddee8bcf697d95aaa59fa06ffb4725 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 11:23:30 +0300
Subject: [PATCH 34/91] Fix instant restarts with additional timeout.

---
 Telegram/SourceFiles/mtproto/connection.cpp       | 13 +++++++------
 Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp |  2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index e21f8df16..5d3895ae0 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -37,12 +37,12 @@ constexpr auto kMarkConnectionOldTimeout = crl::time(192000);
 constexpr auto kPingDelayDisconnect = 60;
 constexpr auto kPingSendAfter = 30 * crl::time(1000);
 constexpr auto kPingSendAfterForce = 45 * crl::time(1000);
-constexpr auto kCheckKeyExpiresIn = TimeId(3600);
 constexpr auto kTemporaryExpiresIn = TimeId(10);
+constexpr auto kBindKeyAdditionalExpiresTimeout = TimeId(30);
 constexpr auto kTestModeDcIdShift = 10000;
 
 // If we can't connect for this time we will ask _instance to update config.
-constexpr auto kRequestConfigTimeout = crl::time(8000);
+constexpr auto kRequestConfigTimeout = 8 * crl::time(1000);
 
 // Don't try to handle messages larger than this size.
 constexpr auto kMaxMessageLength = 16 * 1024 * 1024;
@@ -1278,7 +1278,7 @@ void ConnectionPrivate::handleReceived() {
 		auto from = decryptedInts + kEncryptedHeaderIntsCount;
 		auto end = from + (messageLength / kIntSize);
 		auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
-		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end));
+		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end) + QString(" (keyId:%1)").arg(_temporaryKey->keyId()));
 
 		bool needToHandle = false;
 		{
@@ -2359,8 +2359,9 @@ void ConnectionPrivate::createDcKey() {
 			}
 			_keyCreator = nullptr;
 			_keyBinder = std::make_unique<DcKeyBinder>(std::move(key));
-			result->temporaryKey->setExpiresAt(
-				base::unixtime::now() + kTemporaryExpiresIn);
+			result->temporaryKey->setExpiresAt(base::unixtime::now()
+				+ kTemporaryExpiresIn
+				+ kBindKeyAdditionalExpiresTimeout);
 			applyAuthKey(std::move(result->temporaryKey));
 			return;
 		}
@@ -2482,7 +2483,7 @@ bool ConnectionPrivate::sendSecureRequest(
 	memcpy(request->data() + 2, &session, 2 * sizeof(mtpPrime));
 
 	auto from = request->constData() + 4;
-	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize));
+	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize) + QString(" (keyId:%1)").arg(_temporaryKey->keyId()));
 
 #ifdef TDESKTOP_MTPROTO_OLD
 	uint32 padding = fullSize - 4 - messageSize;
diff --git a/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
index ef0693085..706d6bdca 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
@@ -18,7 +18,7 @@ AuthKey::AuthKey(Type type, DcId dcId, const Data &data)
 , _dcId(dcId)
 , _key(data) {
 	countKeyId();
-	if (type == Type::Generated) {
+	if (type == Type::Generated || type == Type::Temporary) {
 		_lastCheckTime = crl::now();
 	}
 }

From 885738ac32db1fb59a0460508248848258f710d8 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 12:16:53 +0300
Subject: [PATCH 35/91] Always choose correct address for key creation.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 183 +++++++++---------
 Telegram/SourceFiles/mtproto/connection.h     |  12 +-
 .../details/mtproto_bound_key_creator.cpp     |  92 +++++++++
 .../details/mtproto_bound_key_creator.h       |  55 ++++++
 .../mtproto/details/mtproto_dc_key_binder.cpp |  14 --
 .../mtproto/details/mtproto_dc_key_binder.h   |   5 +-
 .../details/mtproto_dc_key_creator.cpp        |   8 +-
 .../mtproto/details/mtproto_dc_key_creator.h  |  41 ++--
 Telegram/gyp/lib_mtproto.gyp                  |   2 +
 9 files changed, 267 insertions(+), 145 deletions(-)
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 5d3895ae0..ff312d44d 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -7,8 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/connection.h"
 
-#include "mtproto/details/mtproto_dc_key_binder.h"
-#include "mtproto/details/mtproto_dc_key_creator.h"
+#include "mtproto/details/mtproto_bound_key_creator.h"
 #include "mtproto/details/mtproto_dump_to_text.h"
 #include "mtproto/session.h"
 #include "mtproto/mtproto_rsa_public_key.h"
@@ -202,7 +201,7 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 }
 
 void ConnectionPrivate::destroyAllConnections() {
-	clearKeyCreatorOnFail();
+	clearUnboundKeyCreator();
 	_waitForBetterTimer.cancel();
 	_waitForReceivedTimer.cancel();
 	_waitForConnectedTimer.cancel();
@@ -244,8 +243,7 @@ ConnectionPrivate::ConnectionPrivate(
 }
 
 ConnectionPrivate::~ConnectionPrivate() {
-	clearKeyCreatorOnFail();
-	cancelKeyBinder();
+	releaseKeyCreationOnFail();
 
 	Expects(_finished);
 	Expects(!_connection);
@@ -445,7 +443,7 @@ void ConnectionPrivate::tryToSend() {
 	const auto needsLayer = !_sessionData->connectionInited();
 	const auto state = getState();
 	const auto sendOnlyFirstPing = (state != ConnectedState);
-	const auto sendAll = !sendOnlyFirstPing && !_keyBinder;
+	const auto sendAll = !sendOnlyFirstPing && !_keyCreator;
 	const auto isMainSession = (GetDcIdShift(_shiftedDcId) == 0);
 	if (sendOnlyFirstPing && !_pingIdToSend) {
 		DEBUG_LOG(("MTP Info: dc %1 not sending, waiting for Connected state, state: %2").arg(_shiftedDcId).arg(state));
@@ -459,10 +457,10 @@ void ConnectionPrivate::tryToSend() {
 	}
 	const auto forceNewMsgId = sendAll
 		&& _sessionData->markSessionAsStarted();
-
-	if (forceNewMsgId) {
-		int a = 0;
+	if (forceNewMsgId && _keyCreator) {
+		_keyCreator->restartBinder();
 	}
+
 	auto pingRequest = SecureRequest();
 	auto ackRequest = SecureRequest();
 	auto resendRequest = SecureRequest();
@@ -529,8 +527,8 @@ void ConnectionPrivate::tryToSend() {
 			httpWaitRequest = SecureRequest::Serialize(MTPHttpWait(
 				MTP_http_wait(MTP_int(100), MTP_int(30), MTP_int(25000))));
 		}
-		if (_keyBinder && !_keyBinder->requested()) {
-			bindDcKeyRequest = _keyBinder->prepareRequest(
+		if (_keyCreator && _keyCreator->bindReadyToRequest()) {
+			bindDcKeyRequest = _keyCreator->prepareBindRequest(
 				_temporaryKey,
 				_sessionData->getSessionId());
 
@@ -857,14 +855,13 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 	_connectionOptions = std::make_unique<ConnectionOptions>(
 		_sessionData->connectionOptions());
 
-	// #TODO race.
-	const auto hasKey = (_sessionData->getTemporaryKey() != nullptr);
+	tryAcquireKeyCreation();
 
 	const auto bareDc = BareDcId(_shiftedDcId);
 	_dcType = _instance->dcOptions()->dcType(_shiftedDcId);
 
 	// Use media_only addresses only if key for this dc is already created.
-	if (_dcType == DcType::MediaDownload && !hasKey) {
+	if (_dcType == DcType::MediaDownload && _keyCreator) {
 		_dcType = DcType::Regular;
 	} else if (_dcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
 		if (!_instance->dcOptions()->hasCDNKeysForDc(bareDc)) {
@@ -1790,7 +1787,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			memcpy(response.data(), from, (end - from) * sizeof(mtpPrime));
 		}
 		if (typeId == mtpc_rpc_error) {
-			if (DcKeyBinder::IsDestroyedTemporaryKeyError(response)) {
+			if (IsDestroyedTemporaryKeyError(response)) {
 				return HandleResult::DestroyTemporaryKey;
 			}
 			// An error could be some RPC_CALL_FAIL or other error inside
@@ -1801,22 +1798,22 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 		requestsAcked(ids, true);
 
-		if (_keyBinder) {
-			const auto result = _keyBinder->handleResponse(
+		if (_keyCreator) {
+			const auto result = _keyCreator->handleBindResponse(
 				reqMsgId,
 				response);
 			if (result == DcKeyBindState::Success) {
 				_sessionData->releaseKeyCreationOnDone(
 					_temporaryKey,
-					base::take(_keyBinder)->persistentKey());
+					base::take(_keyCreator)->bindPersistentKey());
 				_sessionData->queueNeedToResumeAndSend();
 				return HandleResult::Success;
 			} else if (result == DcKeyBindState::Failed
 				|| result == DcKeyBindState::DefinitelyDestroyed) {
 				// #TODO maybe destroy persistent key
 				// crl::on_main(
-				//   _keyBinder->persistentKey()->setLastCheckTime(crl::now());
-				//   instance->keyDestroyedOnServer(BareDcId(shiftedDcId), base::take(_keyBinder)->persistentKey()->keyId());
+				//   _keyCreator->bindPersistentKey()->setLastCheckTime(crl::now());
+				//   instance->keyDestroyedOnServer(BareDcId(shiftedDcId), base::take(_keyCreator)->bindPersistentKey()->keyId());
 				// )
 				_sessionData->queueNeedToResumeAndSend();
 				return HandleResult::Success;
@@ -2251,9 +2248,6 @@ void ConnectionPrivate::removeTestConnection(
 }
 
 void ConnectionPrivate::checkAuthKey() {
-	Expects(_keyCreator == nullptr);
-	Expects(_keyBinder == nullptr || _keyId != 0);
-
 	if (_keyId) {
 		authKeyChecked();
 	} else {
@@ -2262,7 +2256,7 @@ void ConnectionPrivate::checkAuthKey() {
 }
 
 void ConnectionPrivate::updateAuthKey() {
-	if (_keyCreator || _keyBinder) {
+	if (_keyCreator) {
 		return;
 	}
 
@@ -2316,67 +2310,69 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
 		// We are here to destroy an old key, so we're done.
 		LOG(("MTP Error: No key %1 in updateAuthKey() for destroying.").arg(_shiftedDcId));
 		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
-		return;
-	} else if (!_sessionData->acquireKeyCreation()) {
+	} else if (_keyCreator) {
+		DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), creating."));
+		_keyCreator->start(
+			BareDcId(_shiftedDcId),
+			getProtocolDcId(),
+			_connection.get(),
+			_instance->dcOptions());
+	} else {
 		DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), but someone is creating already."));
+	}
+}
+
+void ConnectionPrivate::tryAcquireKeyCreation() {
+	if (_keyCreator || !_sessionData->acquireKeyCreation()) {
 		return;
 	}
 
-	DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), creating."));
-	createDcKey();
-}
-
-void ConnectionPrivate::createDcKey() {
-	Expects(_keyCreator == nullptr);
-	Expects(_keyBinder == nullptr);
-
-	using Result = DcKeyCreator::Result;
-	using Error = DcKeyCreator::Error;
-	auto delegate = DcKeyCreator::Delegate();
-	delegate.done = [=](base::expected<Result, Error> result) {
-		if (result) {
-			DEBUG_LOG(("AuthKey Info: auth key gen succeed, "
-				"ids: (%1, %2) server salts: (%3, %4)"
-				).arg(result->temporaryKey
-					? result->temporaryKey->keyId()
-					: 0
-				).arg(result->persistentKey
-					? result->persistentKey->keyId()
-					: 0
-				).arg(result->temporaryServerSalt
-				).arg(result->persistentServerSalt));
-
-			_sessionData->setSalt(result->temporaryServerSalt);
-			if (result->persistentKey) {
-				_sessionData->clearForNewKey(_instance);
+	using Result = DcKeyResult;
+	using Error = DcKeyError;
+	auto delegate = BoundKeyCreator::Delegate();
+	delegate.unboundReady = [=](base::expected<Result, Error> result) {
+		if (!result) {
+			releaseKeyCreationOnFail();
+			if (result.error() == Error::UnknownPublicKey) {
+				if (_dcType == DcType::Cdn) {
+					LOG(("Warning: CDN public RSA key not found"));
+					requestCDNConfig();
+					return;
+				}
+				LOG(("AuthKey Error: could not choose public RSA key"));
 			}
-
-			auto key = result->persistentKey
-				? std::move(result->persistentKey)
-				: _sessionData->getPersistentKey();
-			if (!key) {
-				restart();
-			}
-			_keyCreator = nullptr;
-			_keyBinder = std::make_unique<DcKeyBinder>(std::move(key));
-			result->temporaryKey->setExpiresAt(base::unixtime::now()
-				+ kTemporaryExpiresIn
-				+ kBindKeyAdditionalExpiresTimeout);
-			applyAuthKey(std::move(result->temporaryKey));
+			restart();
 			return;
 		}
-		clearKeyCreatorOnFail();
-		if (result.error() == Error::UnknownPublicKey) {
-			if (_dcType == DcType::Cdn) {
-				LOG(("Warning: CDN public RSA key not found"));
-				requestCDNConfig();
-			} else {
-				LOG(("AuthKey Error: could not choose public RSA key"));
-				restart();
-			}
-		} else {
-			restart();
+		DEBUG_LOG(("AuthKey Info: unbound key creation succeed, "
+			"ids: (%1, %2) server salts: (%3, %4)"
+			).arg(result->temporaryKey
+				? result->temporaryKey->keyId()
+				: 0
+			).arg(result->persistentKey
+				? result->persistentKey->keyId()
+				: 0
+			).arg(result->temporaryServerSalt
+			).arg(result->persistentServerSalt));
+
+		_sessionData->setSalt(result->temporaryServerSalt);
+		if (result->persistentKey) {
+			_sessionData->clearForNewKey(_instance);
 		}
+
+		auto key = result->persistentKey
+			? std::move(result->persistentKey)
+			: _sessionData->getPersistentKey();
+		if (!key) {
+			releaseKeyCreationOnFail();
+			restart();
+			return;
+		}
+		result->temporaryKey->setExpiresAt(base::unixtime::now()
+			+ kTemporaryExpiresIn
+			+ kBindKeyAdditionalExpiresTimeout);
+		_keyCreator->bind(std::move(key));
+		applyAuthKey(std::move(result->temporaryKey));
 	};
 	delegate.sentSome = [=](uint64 size) {
 		onSentSome(size);
@@ -2384,17 +2380,14 @@ void ConnectionPrivate::createDcKey() {
 	delegate.receivedSome = [=] {
 		onReceivedSome();
 	};
-//	const auto check = (GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift); // #TODO remove kCheckKeyDcShift
-	auto request = DcKeyCreator::Request();
+
+	//	const auto check = (GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift); // #TODO remove kCheckKeyDcShift
+	auto request = DcKeyRequest();
 	request.persistentNeeded = !_sessionData->getPersistentKey();
 	request.temporaryExpiresIn = kTemporaryExpiresIn;
-	_keyCreator = std::make_unique<DcKeyCreator>(
-		BareDcId(_shiftedDcId),
-		getProtocolDcId(),
-		_connection.get(),
-		_instance->dcOptions(),
-		std::move(delegate),
-		request);
+	_keyCreator = std::make_unique<BoundKeyCreator>(
+		request,
+		std::move(delegate));
 }
 
 void ConnectionPrivate::authKeyChecked() {
@@ -2449,7 +2442,7 @@ void ConnectionPrivate::handleError(int errorCode) {
 }
 
 void ConnectionPrivate::destroyTemporaryKey() {
-	cancelKeyBinder();
+	releaseKeyCreationOnFail();
 	if (_temporaryKey) {
 		_sessionData->destroyTemporaryKey(_temporaryKey->keyId());
 	}
@@ -2566,7 +2559,13 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 	return 0;
 }
 
-void ConnectionPrivate::clearKeyCreatorOnFail() {
+void ConnectionPrivate::clearUnboundKeyCreator() {
+	if (_keyCreator) {
+		_keyCreator->stop();
+	}
+}
+
+void ConnectionPrivate::releaseKeyCreationOnFail() {
 	if (!_keyCreator) {
 		return;
 	}
@@ -2574,14 +2573,6 @@ void ConnectionPrivate::clearKeyCreatorOnFail() {
 	_sessionData->releaseKeyCreationOnFail();
 }
 
-void ConnectionPrivate::cancelKeyBinder() {
-	if (!_keyBinder) {
-		return;
-	}
-	_keyBinder = nullptr;
-	_sessionData->releaseKeyCreationOnFail();
-}
-
 void ConnectionPrivate::stop() {
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index d786f80ea..b8c0d536d 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -16,8 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace MTP {
 namespace details {
-class DcKeyCreator;
-class DcKeyBinder;
+class BoundKeyCreator;
 } // namespace details
 
 // How much time to wait for some more requests, when sending msg acks.
@@ -179,13 +178,13 @@ private:
 		crl::time msCanWait = 0,
 		bool forceContainer = false);
 
-	void createDcKey();
+	void tryAcquireKeyCreation();
 	void resetSession();
 	void checkAuthKey();
 	void authKeyChecked();
 	void destroyTemporaryKey();
-	void clearKeyCreatorOnFail();
-	void cancelKeyBinder();
+	void clearUnboundKeyCreator();
+	void releaseKeyCreationOnFail();
 	void applyAuthKey(AuthKeyPtr &&temporaryKey);
 
 	const not_null<Instance*> _instance;
@@ -232,8 +231,7 @@ private:
 	std::shared_ptr<SessionData> _sessionData;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 
-	std::unique_ptr<details::DcKeyCreator> _keyCreator;
-	std::unique_ptr<details::DcKeyBinder> _keyBinder;
+	std::unique_ptr<details::BoundKeyCreator> _keyCreator;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
new file mode 100644
index 000000000..ab8dd2488
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
@@ -0,0 +1,92 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/details/mtproto_bound_key_creator.h"
+
+namespace MTP::details {
+
+BoundKeyCreator::BoundKeyCreator(DcKeyRequest request, Delegate delegate)
+: _request(request)
+, _delegate(std::move(delegate)) {
+}
+
+void BoundKeyCreator::start(
+		DcId dcId,
+		int16 protocolDcId,
+		not_null<AbstractConnection*> connection,
+		not_null<DcOptions*> dcOptions) {
+	Expects(!_creator.has_value());
+
+	auto delegate = DcKeyCreator::Delegate();
+	delegate.done = _delegate.unboundReady;
+	delegate.sentSome = _delegate.sentSome;
+	delegate.receivedSome = _delegate.receivedSome;
+
+	_creator.emplace(
+		dcId,
+		protocolDcId,
+		connection,
+		dcOptions,
+		std::move(delegate),
+		_request);
+}
+
+void BoundKeyCreator::stop() {
+	_creator = std::nullopt;
+}
+
+void BoundKeyCreator::bind(AuthKeyPtr &&persistentKey) {
+	stop();
+	_binder.emplace(std::move(persistentKey));
+}
+
+void BoundKeyCreator::restartBinder() {
+	if (_binder) {
+		_binder.emplace(_binder->persistentKey());
+	}
+}
+
+bool BoundKeyCreator::bindReadyToRequest() const {
+	return _binder ? !_binder->requested() : false;
+}
+
+SecureRequest BoundKeyCreator::prepareBindRequest(
+		const AuthKeyPtr &temporaryKey,
+		uint64 sessionId) {
+	Expects(_binder.has_value());
+
+	return _binder->prepareRequest(temporaryKey, sessionId);
+}
+
+DcKeyBindState BoundKeyCreator::handleBindResponse(
+		MTPlong requestMsgId,
+		const mtpBuffer &response) {
+	return _binder
+		? _binder->handleResponse(requestMsgId, response)
+		: DcKeyBindState::Unknown;
+}
+
+AuthKeyPtr BoundKeyCreator::bindPersistentKey() const {
+	Expects(_binder.has_value());
+
+	return _binder->persistentKey();
+}
+
+bool IsDestroyedTemporaryKeyError(const mtpBuffer &buffer) {
+	auto from = buffer.data();
+	const auto end = from + buffer.size();
+	auto error = MTPRpcError();
+	if (!error.read(from, from + buffer.size())) {
+		return false;
+	}
+	return error.match([&](const MTPDrpc_error &data) {
+		return (data.verror_code().v == 401)
+			&& (data.verror_message().v == "AUTH_KEY_PERM_EMPTY");
+	});
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
new file mode 100644
index 000000000..78d624b96
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
@@ -0,0 +1,55 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "mtproto/details/mtproto_dc_key_creator.h"
+#include "mtproto/details/mtproto_dc_key_binder.h"
+
+namespace MTP::details {
+
+class BoundKeyCreator final {
+public:
+	struct Delegate {
+		Fn<void(base::expected<DcKeyResult, DcKeyError>)> unboundReady;
+		Fn<void(uint64)> sentSome;
+		Fn<void()> receivedSome;
+	};
+
+	BoundKeyCreator(DcKeyRequest request, Delegate delegate);
+
+	void start(
+		DcId dcId,
+		int16 protocolDcId,
+		not_null<AbstractConnection*> connection,
+		not_null<DcOptions*> dcOptions);
+	void stop();
+
+	void bind(AuthKeyPtr &&persistentKey);
+	void restartBinder();
+	[[nodiscard]] bool bindReadyToRequest() const;
+	[[nodiscard]] SecureRequest prepareBindRequest(
+		const AuthKeyPtr &temporaryKey,
+		uint64 sessionId);
+	[[nodiscard]] DcKeyBindState handleBindResponse(
+		MTPlong requestMsgId,
+		const mtpBuffer &response);
+	[[nodiscard]] AuthKeyPtr bindPersistentKey() const;
+
+private:
+	const DcKeyRequest _request;
+	Delegate _delegate;
+
+	std::optional<DcKeyCreator> _creator;
+	std::optional<DcKeyBinder> _binder;
+
+};
+
+
+[[nodiscard]] bool IsDestroyedTemporaryKeyError(const mtpBuffer &buffer);
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
index bd2f3686b..44ca8a4c7 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
@@ -140,18 +140,4 @@ AuthKeyPtr DcKeyBinder::persistentKey() const {
 	return _persistentKey;
 }
 
-bool DcKeyBinder::IsDestroyedTemporaryKeyError(
-		const mtpBuffer &buffer) {
-	auto from = buffer.data();
-	const auto end = from + buffer.size();
-	auto error = MTPRpcError();
-	if (!error.read(from, from + buffer.size())) {
-		return false;
-	}
-	return error.match([&](const MTPDrpc_error &data) {
-		return (data.verror_code().v == 401)
-			&& (data.verror_message().v == "AUTH_KEY_PERM_EMPTY");
-	});
-}
-
 } // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
index 2ea16f33e..db311b3b4 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
@@ -25,7 +25,7 @@ enum class DcKeyBindState {
 
 class DcKeyBinder final {
 public:
-	DcKeyBinder(AuthKeyPtr &&persistentKey);
+	explicit DcKeyBinder(AuthKeyPtr &&persistentKey);
 
 	[[nodiscard]] bool requested() const;
 	[[nodiscard]] SecureRequest prepareRequest(
@@ -36,9 +36,6 @@ public:
 		const mtpBuffer &response);
 	[[nodiscard]] AuthKeyPtr persistentKey() const;
 
-	[[nodiscard]] static bool IsDestroyedTemporaryKeyError(
-		const mtpBuffer &buffer);
-
 private:
 	AuthKeyPtr _persistentKey;
 	mtpMsgId _requestMsgId = 0;
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index bf8fac938..6b90e1b6a 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -169,7 +169,7 @@ DcKeyCreator::DcKeyCreator(
 	not_null<AbstractConnection*> connection,
 	not_null<DcOptions*> dcOptions,
 	Delegate delegate,
-	Request request)
+	DcKeyRequest request)
 : _connection(connection)
 , _dcOptions(dcOptions)
 , _dcId(dcId)
@@ -313,7 +313,7 @@ void DcKeyCreator::pqAnswered(
 			_dcId,
 			data.vserver_public_key_fingerprints().v);
 		if (!rsaKey.valid()) {
-			return failed(Error::UnknownPublicKey);
+			return failed(DcKeyError::UnknownPublicKey);
 		}
 
 		attempt->data.server_nonce = data.vserver_nonce();
@@ -596,7 +596,7 @@ void DcKeyCreator::dhClientParamsAnswered(
 	});
 }
 
-void DcKeyCreator::failed(Error error) {
+void DcKeyCreator::failed(DcKeyError error) {
 	stopReceiving();
 	auto onstack = base::take(_delegate.done);
 	onstack(tl::unexpected(error));
@@ -610,7 +610,7 @@ void DcKeyCreator::done() {
 	Assert(_temporary.stage == Stage::Ready);
 	Assert(_persistent.stage == Stage::Ready || _persistent.stage == Stage::None);
 
-	auto result = Result();
+	auto result = DcKeyResult();
 	result.temporaryKey = std::make_shared<AuthKey>(
 		AuthKey::Type::Temporary,
 		_dcId,
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
index e98312694..756044444 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -21,24 +21,27 @@ namespace MTP::details {
 
 using namespace ::MTP::internal;
 
+struct DcKeyRequest {
+	TimeId temporaryExpiresIn = 0;
+	bool persistentNeeded = false;
+};
+
+enum class DcKeyError {
+	UnknownPublicKey,
+	Other,
+};
+
+struct DcKeyResult {
+	AuthKeyPtr persistentKey;
+	AuthKeyPtr temporaryKey;
+	uint64 temporaryServerSalt = 0;
+	uint64 persistentServerSalt = 0;
+};
+
 class DcKeyCreator final {
 public:
-	struct Request {
-		TimeId temporaryExpiresIn = 0;
-		bool persistentNeeded = false;
-	};
-	enum class Error {
-		UnknownPublicKey,
-		Other,
-	};
-	struct Result {
-		AuthKeyPtr persistentKey;
-		AuthKeyPtr temporaryKey;
-		uint64 temporaryServerSalt = 0;
-		uint64 persistentServerSalt = 0;
-	};
 	struct Delegate {
-		FnMut<void(base::expected<Result, Error>)> done;
+		Fn<void(base::expected<DcKeyResult, DcKeyError>)> done;
 		Fn<void(uint64)> sentSome;
 		Fn<void()> receivedSome;
 	};
@@ -49,7 +52,7 @@ public:
 		not_null<AbstractConnection*> connection,
 		not_null<DcOptions*> dcOptions,
 		Delegate delegate,
-		Request request);
+		DcKeyRequest request);
 	~DcKeyCreator();
 
 private:
@@ -120,21 +123,19 @@ private:
 		const MTPset_client_DH_params_answer &data);
 
 	void stopReceiving();
-	void failed(Error error = Error::Other);
+	void failed(DcKeyError error = DcKeyError::Other);
 	void done();
 
 	const not_null<AbstractConnection*> _connection;
 	const not_null<DcOptions*> _dcOptions;
 	const DcId _dcId = 0;
 	const int16 _protocolDcId = 0;
-	const Request _request;
+	const DcKeyRequest _request;
 	Delegate _delegate;
 
 	Attempt _temporary;
 	Attempt _persistent;
 
-	FnMut<void(base::expected<Result, Error>)> _done;
-
 };
 
 } // namespace MTP::details
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index 83fb05965..93a02d331 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -34,6 +34,8 @@
       '<(src_loc)',
     ],
     'sources': [
+      '<(src_loc)/mtproto/details/mtproto_bound_key_creator.cpp',
+      '<(src_loc)/mtproto/details/mtproto_bound_key_creator.h',
       '<(src_loc)/mtproto/details/mtproto_dc_key_binder.cpp',
       '<(src_loc)/mtproto/details/mtproto_dc_key_binder.h',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.cpp',

From bdc7f4114faa472407e5afbc27eb826e4cd38bf2 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 13:41:14 +0300
Subject: [PATCH 36/91] Move some things from SessionData.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 272 ++++++++++--------
 Telegram/SourceFiles/mtproto/connection.h     |  28 +-
 .../details/mtproto_received_ids_manager.cpp  |  54 ++++
 .../details/mtproto_received_ids_manager.h    |  38 +++
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   1 +
 Telegram/SourceFiles/mtproto/session.cpp      | 128 ---------
 Telegram/SourceFiles/mtproto/session.h        | 112 +-------
 Telegram/gyp/lib_mtproto.gyp                  |   2 +
 8 files changed, 280 insertions(+), 355 deletions(-)
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.h

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index ff312d44d..9c206ff27 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -39,6 +39,7 @@ constexpr auto kPingSendAfterForce = 45 * crl::time(1000);
 constexpr auto kTemporaryExpiresIn = TimeId(10);
 constexpr auto kBindKeyAdditionalExpiresTimeout = TimeId(30);
 constexpr auto kTestModeDcIdShift = 10000;
+constexpr auto kCheckSentRequestsEach = 1 * crl::time(1000);
 
 // If we can't connect for this time we will ask _instance to update config.
 constexpr auto kRequestConfigTimeout = 8 * crl::time(1000);
@@ -46,9 +47,19 @@ constexpr auto kRequestConfigTimeout = 8 * crl::time(1000);
 // Don't try to handle messages larger than this size.
 constexpr auto kMaxMessageLength = 16 * 1024 * 1024;
 
+// How much time passed from send till we resend request or check its state.
+constexpr auto kCheckSentRequestTimeout = 10 * crl::time(1000);
+
+// How much time to wait for some more requests,
+// when resending request or checking its state.
+constexpr auto kSendStateRequestWaiting = crl::time(1000);
+
+// Container lives 10 minutes in haveSent map.
+constexpr auto kContainerLives = TimeId(600);
+
 using namespace details;
 
-QString LogIdsVector(const QVector<MTPlong> &ids) {
+[[nodiscard]] QString LogIdsVector(const QVector<MTPlong> &ids) {
 	if (!ids.size()) return "[]";
 	auto idsStr = QString("[%1").arg(ids.cbegin()->v);
 	for (const auto &id : ids) {
@@ -57,6 +68,15 @@ QString LogIdsVector(const QVector<MTPlong> &ids) {
 	return idsStr + "]";
 }
 
+[[nodiscard]] QString LogIds(const QVector<uint64> &ids) {
+	if (!ids.size()) return "[]";
+	auto idsStr = QString("[%1").arg(*ids.cbegin());
+	for (const auto id : ids) {
+		idsStr += QString(", %2").arg(id);
+	}
+	return idsStr + "]";
+}
+
 void wrapInvokeAfter(SecureRequest &to, const SecureRequest &from, const RequestMap &haveSent, int32 skipBeforeRequest = 0) {
 	const auto afterId = *(mtpMsgId*)(from->after->data() + 4);
 	const auto i = afterId ? haveSent.constFind(afterId) : haveSent.cend();
@@ -200,6 +220,47 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 		: testedDcId;
 }
 
+void ConnectionPrivate::checkSentRequests() {
+	QVector<mtpMsgId> removingIds; // remove very old (10 minutes) containers and resend requests
+	auto requesting = false;
+	{
+		QReadLocker locker(_sessionData->haveSentMutex());
+		auto &haveSent = _sessionData->haveSentMap();
+		const auto haveSentCount = haveSent.size();
+		auto ms = crl::now();
+		for (auto i = haveSent.begin(), e = haveSent.end(); i != e; ++i) {
+			auto &req = i.value();
+			if (req->msDate > 0) {
+				if (req->msDate + kCheckSentRequestTimeout < ms) {
+					// Need to check state.
+					req->msDate = ms;
+					if (_stateRequestData.emplace(i.key()).second) {
+						requesting = true;
+					}
+				}
+			} else if (base::unixtime::now()
+				> int32(i.key() >> 32) + kContainerLives) {
+				removingIds.reserve(haveSentCount);
+				removingIds.push_back(i.key());
+			}
+		}
+	}
+	if (requesting) {
+		_sessionData->queueSendAnything(kSendStateRequestWaiting);
+	}
+	if (!removingIds.isEmpty()) {
+		QWriteLocker locker(_sessionData->haveSentMutex());
+		auto &haveSent = _sessionData->haveSentMap();
+		for (uint32 i = 0, l = removingIds.size(); i < l; ++i) {
+			auto j = haveSent.find(removingIds[i]);
+			if (j != haveSent.cend()) {
+				Assert(!j.value()->requestId);
+				haveSent.erase(j);
+			}
+		}
+	}
+}
+
 void ConnectionPrivate::destroyAllConnections() {
 	clearUnboundKeyCreator();
 	_waitForBetterTimer.cancel();
@@ -228,12 +289,16 @@ ConnectionPrivate::ConnectionPrivate(
 , _waitForReceived(kMinReceiveTimeout)
 , _waitForConnected(kMinConnectedTimeout)
 , _pingSender(thread, [=] { sendPingByTimer(); })
+, _checkSentRequestsTimer(thread, [=] { checkSentRequests(); })
 , _sessionData(std::move(data)) {
 	Expects(_shiftedDcId != 0);
 
 	moveToThread(thread);
 
-	connect(thread, &QThread::started, this, [=] { connectToServer(); });
+	connect(thread, &QThread::started, this, [=] {
+		_checkSentRequestsTimer.callEach(kCheckSentRequestsEach);
+		connectToServer();
+	});
 	connect(thread, &QThread::finished, this, [=] { finishAndDestroy(); });
 
 	connect(_sessionData->owner(), SIGNAL(authKeyChanged()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
@@ -315,19 +380,42 @@ void ConnectionPrivate::resetSession() {
 	_needSessionReset = false;
 
 	DEBUG_LOG(("MTP Info: creating new session in resetSession."));
-	_sessionData->changeSessionId();
-
-	// #TODO move to sessionData, clear on changeSessionIdLocked.
-	_ackRequestData.clear();
-	_resendRequestData.clear();
-	{
-		QWriteLocker locker5(_sessionData->stateRequestMutex());
-		_sessionData->stateRequestMap().clear();
-	}
+	changeSessionId();
 
 	_sessionData->queueResetDone();
 }
 
+void ConnectionPrivate::changeSessionId() {
+	auto sessionId = _sessionId;
+	do {
+		sessionId = openssl::RandomValue<uint64>();
+	} while (_sessionId == sessionId);
+
+	DEBUG_LOG(("MTP Info: setting server_session: %1").arg(sessionId));
+
+	_sessionId = sessionId;
+	_messagesCounter = 0;
+	_sessionMarkedAsStarted = false;
+	_ackRequestData.clear();
+	_resendRequestData.clear();
+	_stateRequestData.clear();
+	_receivedMessageIds.clear();
+}
+
+uint32 ConnectionPrivate::nextRequestSeqNumber(bool needAck) {
+	const auto result = _messagesCounter;
+	_messagesCounter += (needAck ? 1 : 0);
+	return result * 2 + (needAck ? 1 : 0);
+}
+
+bool ConnectionPrivate::markSessionAsStarted() {
+	if (_sessionMarkedAsStarted) {
+		return false;
+	}
+	_sessionMarkedAsStarted = true;
+	return true;
+}
+
 mtpMsgId ConnectionPrivate::prepareToSend(
 		SecureRequest &request,
 		mtpMsgId currentLastId,
@@ -349,7 +437,7 @@ mtpMsgId ConnectionPrivate::prepareToSend(
 			: msgId;
 	}
 	request.setMsgId(currentLastId);
-	request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
+	request.setSeqNo(nextRequestSeqNumber(request.needAck()));
 	if (request->requestId) {
 		MTP_LOG(_shiftedDcId, ("[r%1] msg_id 0 -> %2").arg(request->requestId).arg(currentLastId));
 	}
@@ -412,7 +500,7 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 	}
 
 	request.setMsgId(newId);
-	request.setSeqNo(_sessionData->nextRequestSeqNumber(request.needAck()));
+	request.setSeqNo(nextRequestSeqNumber(request.needAck()));
 	return newId;
 }
 
@@ -455,8 +543,7 @@ void ConnectionPrivate::tryToSend() {
 		&& _pingSendAt <= crl::now()) {
 		_pingIdToSend = openssl::RandomValue<mtpPingId>();
 	}
-	const auto forceNewMsgId = sendAll
-		&& _sessionData->markSessionAsStarted();
+	const auto forceNewMsgId = sendAll && markSessionAsStarted();
 	if (forceNewMsgId && _keyCreator) {
 		_keyCreator->restartBinder();
 	}
@@ -504,22 +591,14 @@ void ConnectionPrivate::tryToSend() {
 				MTP_msg_resend_req(MTP_vector<MTPlong>(
 					base::take(_resendRequestData)))));
 		}
-
-		auto stateReq = QVector<MTPlong>();
-		{
-			QWriteLocker locker(_sessionData->stateRequestMutex());
-			auto &ids = _sessionData->stateRequestMap();
-			if (!ids.isEmpty()) {
-				stateReq.reserve(ids.size());
-				for (auto i = ids.cbegin(), e = ids.cend(); i != e; ++i) {
-					stateReq.push_back(MTP_long(i.key()));
-				}
+		if (!_stateRequestData.empty()) {
+			auto ids = QVector<MTPlong>();
+			ids.reserve(_stateRequestData.size());
+			for (const auto id : base::take(_stateRequestData)) {
+				ids.push_back(MTP_long(id));
 			}
-			ids.clear();
-		}
-		if (!stateReq.isEmpty()) {
 			stateRequest = SecureRequest::Serialize(MTPMsgsStateReq(
-				MTP_msgs_state_req(MTP_vector<MTPlong>(stateReq))));
+				MTP_msgs_state_req(MTP_vector<MTPlong>(ids))));
 			// Add to haveSent / wereAcked maps, but don't add to requestMap.
 			stateRequest->requestId = GetNextRequestId();
 		}
@@ -530,14 +609,13 @@ void ConnectionPrivate::tryToSend() {
 		if (_keyCreator && _keyCreator->bindReadyToRequest()) {
 			bindDcKeyRequest = _keyCreator->prepareBindRequest(
 				_temporaryKey,
-				_sessionData->getSessionId());
+				_sessionId);
 
 			// This is a special request with msgId used inside the message
 			// body, so it is prepared already with a msgId and we place
 			// seqNo for it manually here.
 			bindDcKeyRequest.setSeqNo(
-				_sessionData->nextRequestSeqNumber(
-					bindDcKeyRequest.needAck()));
+				nextRequestSeqNumber(bindDcKeyRequest.needAck()));
 		//} else if (!_keyChecker) {
 		//	if (const auto &keyForCheck = _sessionData->getKeyForCheck()) {
 		//		_keyChecker = std::make_unique<details::DcKeyChecker>(
@@ -546,14 +624,13 @@ void ConnectionPrivate::tryToSend() {
 		//			keyForCheck);
 		//		bindDcKeyRequest = _keyChecker->prepareRequest(
 		//			_temporaryKey,
-		//			_sessionData->getSessionId());
+		//			_sessionId);
 
 		//		// This is a special request with msgId used inside the message
 		//		// body, so it is prepared already with a msgId and we place
 		//		// seqNo for it manually here.
 		//		bindDcKeyRequest.setSeqNo(
-		//			_sessionData->nextRequestSeqNumber(
-		//				bindDcKeyRequest.needAck()));
+		//			nextRequestSeqNumber(bindDcKeyRequest.needAck()));
 		//	}
 		}
 	}
@@ -1229,10 +1306,9 @@ void ConnectionPrivate::handleReceived() {
 
 		TCP_LOG(("TCP Info: decrypted message %1,%2,%3 is %4 len").arg(msgId).arg(seqNo).arg(Logs::b(needAck)).arg(fullDataLength));
 
-		uint64 serverSession = _sessionData->getSessionId();
-		if (session != serverSession) {
+		if (session != _sessionId) {
 			LOG(("MTP Error: bad server session received"));
-			TCP_LOG(("MTP Error: bad server session %1 instead of %2 in message received").arg(session).arg(serverSession));
+			TCP_LOG(("MTP Error: bad server session %1 instead of %2 in message received").arg(session).arg(_sessionId));
 
 			return restart();
 		}
@@ -1247,23 +1323,22 @@ void ConnectionPrivate::handleReceived() {
 		}
 
 		bool badTime = false;
-		uint64 mySalt = _sessionData->getSalt();
 		if (serverTime > clientTime + 60 || serverTime + 300 < clientTime) {
 			DEBUG_LOG(("MTP Info: bad server time from msg_id: %1, my time: %2").arg(serverTime).arg(clientTime));
 			badTime = true;
 		}
 
 		bool wasConnected = (getState() == ConnectedState);
-		if (serverSalt != mySalt) {
+		if (serverSalt != _sessionSalt) {
 			if (!badTime) {
-				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2, updating...").arg(serverSalt).arg(mySalt));
-				_sessionData->setSalt(serverSalt);
+				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2, updating...").arg(serverSalt).arg(_sessionSalt));
+				_sessionSalt = serverSalt;
 
 				if (setState(ConnectedState, ConnectingState)) {
 					_sessionData->resendAll();
 				}
 			} else {
-				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2").arg(serverSalt).arg(mySalt));
+				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2").arg(serverSalt).arg(_sessionSalt));
 			}
 		} else {
 			serverSalt = 0; // dont pass to handle method, so not to lock in setSalt()
@@ -1277,18 +1352,10 @@ void ConnectionPrivate::handleReceived() {
 		auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
 		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end) + QString(" (keyId:%1)").arg(_temporaryKey->keyId()));
 
-		bool needToHandle = false;
-		{
-			QWriteLocker lock(_sessionData->receivedIdsMutex());
-			needToHandle = _sessionData->receivedIdsSet().registerMsgId(msgId, needAck);
-		}
-		if (needToHandle) {
+		if (_receivedMessageIds.registerMsgId(msgId, needAck)) {
 			res = handleOneReceived(from, end, msgId, serverTime, serverSalt, badTime);
 		}
-		{
-			QWriteLocker lock(_sessionData->receivedIdsMutex());
-			_sessionData->receivedIdsSet().shrink();
-		}
+		_receivedMessageIds.shrink();
 
 		// send acks
 		if (const auto toAckSize = _ackRequestData.size()) {
@@ -1389,13 +1456,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				return HandleResult::ParseError;
 			}
 
-			bool needToHandle = false;
-			{
-				QWriteLocker lock(_sessionData->receivedIdsMutex());
-				needToHandle = _sessionData->receivedIdsSet().registerMsgId(inMsgId.v, needAck);
-			}
 			auto res = HandleResult::Success; // if no need to handle, then succeed
-			if (needToHandle) {
+			if (_receivedMessageIds.registerMsgId(inMsgId.v, needAck)) {
 				res = handleOneReceived(from, otherEnd, inMsgId.v, serverTime, serverSalt, badTime);
 				badTime = false;
 			}
@@ -1489,7 +1551,9 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			}
 
 			if (needResend) { // bad msg_id or bad container
-				if (serverSalt) _sessionData->setSalt(serverSalt);
+				if (serverSalt) {
+					_sessionSalt = serverSalt;
+				}
 				base::unixtime::update(serverTime, true);
 
 				DEBUG_LOG(("Message Info: unixtime updated, now %1, resending in container...").arg(serverTime));
@@ -1497,7 +1561,9 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				resend(resendId, 0, true);
 			} else { // must create new session, because msg_id and msg_seqno are inconsistent
 				if (badTime) {
-					if (serverSalt) _sessionData->setSalt(serverSalt);
+					if (serverSalt) {
+						_sessionSalt = serverSalt;
+					}
 					base::unixtime::update(serverTime, true);
 					badTime = false;
 				}
@@ -1543,8 +1609,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			return (badTime ? HandleResult::Ignored : HandleResult::Success);
 		}
 
-		uint64 serverSalt = data.vnew_server_salt().v;
-		_sessionData->setSalt(serverSalt);
+		_sessionSalt = data.vnew_server_salt().v;
 		base::unixtime::update(serverTime);
 
 		if (setState(ConnectedState, ConnectingState)) {
@@ -1573,10 +1638,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 
 		QByteArray info(idsCount, Qt::Uninitialized);
 		{
-			QReadLocker lock(_sessionData->receivedIdsMutex());
-			auto &receivedIds = _sessionData->receivedIdsSet();
-			auto minRecv = receivedIds.min();
-			auto maxRecv = receivedIds.max();
+			const auto minRecv = _receivedMessageIds.min();
+			const auto maxRecv = _receivedMessageIds.max();
 
 			QReadLocker locker(_sessionData->wereAckedMutex());
 			const auto &wereAcked = _sessionData->wereAckedMap();
@@ -1590,15 +1653,15 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				} else if (reqMsgId > maxRecv) {
 					state |= 0x03;
 				} else {
-					auto msgIdState = receivedIds.lookup(reqMsgId);
-					if (msgIdState == ReceivedMsgIds::State::NotFound) {
+					auto msgIdState = _receivedMessageIds.lookup(reqMsgId);
+					if (msgIdState == ReceivedIdsManager::State::NotFound) {
 						state |= 0x02;
 					} else {
 						state |= 0x04;
 						if (wereAcked.constFind(reqMsgId) != wereAckedEnd) {
 							state |= 0x80; // we know, that server knows, that we received request
 						}
-						if (msgIdState == ReceivedMsgIds::State::NeedsAck) { // need ack, so we sent ack
+						if (msgIdState == ReceivedIdsManager::State::NeedsAck) { // need ack, so we sent ack
 							state |= 0x08;
 						} else {
 							state |= 0x10;
@@ -1632,7 +1695,9 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				return (badTime ? HandleResult::Ignored : HandleResult::Success);
 			}
 			if (badTime) {
-				if (serverSalt) _sessionData->setSalt(serverSalt); // requestsFixTimeSalt with no lookup
+				if (serverSalt) {
+					_sessionSalt = serverSalt; // requestsFixTimeSalt with no lookup
+				}
 				base::unixtime::update(serverTime, true);
 
 				DEBUG_LOG(("Message Info: unixtime updated from mtpc_msgs_state_info, now %1").arg(serverTime));
@@ -1710,13 +1775,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 		requestsAcked(ids);
 
-		bool received = false;
-		MTPlong resMsgId = data.vanswer_msg_id();
-		{
-			QReadLocker lock(_sessionData->receivedIdsMutex());
-			received = (_sessionData->receivedIdsSet().lookup(resMsgId.v) != ReceivedMsgIds::State::NotFound);
-		}
-		if (received) {
+		const auto resMsgId = data.vanswer_msg_id();
+		if (_receivedMessageIds.lookup(resMsgId.v) != ReceivedIdsManager::State::NotFound) {
 			_ackRequestData.push_back(resMsgId);
 		} else {
 			DEBUG_LOG(("Message Info: answer message %1 was not received, requesting...").arg(resMsgId.v));
@@ -1737,13 +1797,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 
 		DEBUG_LOG(("Message Info: msg new detailed info, answerId %2, status %3, bytes %4").arg(data.vanswer_msg_id().v).arg(data.vstatus().v).arg(data.vbytes().v));
 
-		bool received = false;
-		MTPlong resMsgId = data.vanswer_msg_id();
-		{
-			QReadLocker lock(_sessionData->receivedIdsMutex());
-			received = (_sessionData->receivedIdsSet().lookup(resMsgId.v) != ReceivedMsgIds::State::NotFound);
-		}
-		if (received) {
+		const auto resMsgId = data.vanswer_msg_id();
+		if (_receivedMessageIds.lookup(resMsgId.v) != ReceivedIdsManager::State::NotFound) {
 			_ackRequestData.push_back(resMsgId);
 		} else {
 			DEBUG_LOG(("Message Info: answer message %1 was not received, requesting...").arg(resMsgId.v));
@@ -1847,7 +1902,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 
 		DEBUG_LOG(("Message Info: new server session created, unique_id %1, first_msg_id %2, server_salt %3").arg(data.vunique_id().v).arg(data.vfirst_msg_id().v).arg(data.vserver_salt().v));
-		_sessionData->setSalt(data.vserver_salt().v);
+		_sessionSalt = data.vserver_salt().v;
 
 		mtpMsgId firstMsgId = data.vfirst_msg_id().v;
 		QVector<quint64> toResend;
@@ -1993,7 +2048,9 @@ bool ConnectionPrivate::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 s
 
 	for (uint32 i = 0; i < idsCount; ++i) {
 		if (wasSent(ids[i].v)) {// found such msg_id in recent acked requests or in recent sent requests
-			if (serverSalt) _sessionData->setSalt(serverSalt);
+			if (serverSalt) {
+				_sessionSalt = serverSalt;
+			}
 			base::unixtime::update(serverTime, true);
 			return true;
 		}
@@ -2264,6 +2321,16 @@ void ConnectionPrivate::updateAuthKey() {
 	applyAuthKey(_sessionData->getTemporaryKey());
 }
 
+void ConnectionPrivate::setCurrentKeyId(uint64 newKeyId) {
+	if (_keyId == newKeyId) {
+		return;
+	}
+	_keyId = newKeyId;
+
+	DEBUG_LOG(("MTP Info: auth key id set to id %1").arg(newKeyId));
+	changeSessionId();
+}
+
 void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
 	_temporaryKey = std::move(temporaryKey);
 	const auto newKeyId = _temporaryKey ? _temporaryKey->keyId() : 0;
@@ -2271,15 +2338,7 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
 		if (_keyId == newKeyId) {
 			return;
 		}
-		_keyId = 0;
-		if (_sessionData->setCurrentKeyId(_keyId)) {
-			_ackRequestData.clear(); // #TODO move to sessionData.
-			_resendRequestData.clear();
-			{
-				QWriteLocker locker5(_sessionData->stateRequestMutex());
-				_sessionData->stateRequestMap().clear();
-			}
-		}
+		setCurrentKeyId(0);
 		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed, restarting..."
 			).arg(_shiftedDcId));
 		if (_connection) {
@@ -2290,15 +2349,7 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
 	if (!_connection) {
 		return;
 	}
-	if (newKeyId && _sessionData->setCurrentKeyId(newKeyId)) {
-		_ackRequestData.clear(); // #TODO move to sessionData.
-		_resendRequestData.clear();
-		{
-			QWriteLocker locker5(_sessionData->stateRequestMutex());
-			_sessionData->stateRequestMap().clear();
-		}
-	}
-	_keyId = newKeyId;
+	setCurrentKeyId(newKeyId);
 	Assert(!_connection->sentEncryptedWithKeyId());
 
 	DEBUG_LOG(("AuthKey Info: Connection update key from Session, dc %1 result: %2").arg(_shiftedDcId).arg(Logs::mb(&_keyId, sizeof(_keyId)).str()));
@@ -2355,7 +2406,7 @@ void ConnectionPrivate::tryAcquireKeyCreation() {
 			).arg(result->temporaryServerSalt
 			).arg(result->persistentServerSalt));
 
-		_sessionData->setSalt(result->temporaryServerSalt);
+		_sessionSalt = result->temporaryServerSalt;
 		if (result->persistentKey) {
 			_sessionData->clearForNewKey(_instance);
 		}
@@ -2395,7 +2446,7 @@ void ConnectionPrivate::authKeyChecked() {
 		handleReceived();
 	});
 
-	if (_sessionData->getSalt() && setState(ConnectedState)) {
+	if (_sessionSalt && setState(ConnectedState)) {
 		_sessionData->resendAll();
 	} // else receive salt in bad_server_salt first, then try to send all the requests
 
@@ -2469,11 +2520,8 @@ bool ConnectionPrivate::sendSecureRequest(
 		return false;
 	}
 
-	auto session = _sessionData->getSessionId();
-	auto salt = _sessionData->getSalt();
-
-	memcpy(request->data() + 0, &salt, 2 * sizeof(mtpPrime));
-	memcpy(request->data() + 2, &session, 2 * sizeof(mtpPrime));
+	memcpy(request->data() + 0, &_sessionSalt, 2 * sizeof(mtpPrime));
+	memcpy(request->data() + 2, &_sessionId, 2 * sizeof(mtpPrime));
 
 	auto from = request->constData() + 4;
 	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize) + QString(" (keyId:%1)").arg(_temporaryKey->keyId()));
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index b8c0d536d..77e7debc0 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "mtproto/details/mtproto_received_ids_manager.h"
 #include "mtproto/mtproto_auth_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/connection_abstract.h"
@@ -133,7 +134,9 @@ private:
 
 	void confirmBestConnection();
 	void removeTestConnection(not_null<AbstractConnection*> connection);
-	int16 getProtocolDcId() const;
+	[[nodiscard]] int16 getProtocolDcId() const;
+
+	void checkSentRequests();
 
 	mtpMsgId placeToContainer(
 		SecureRequest &toSendRequest,
@@ -187,6 +190,12 @@ private:
 	void releaseKeyCreationOnFail();
 	void applyAuthKey(AuthKeyPtr &&temporaryKey);
 
+	void setCurrentKeyId(uint64 newKeyId);
+	void changeSessionId();
+	void setSessionSalt(uint64 salt);
+	[[nodiscard]] bool markSessionAsStarted();
+	[[nodiscard]] uint32 nextRequestSeqNumber(bool needAck);
+
 	const not_null<Instance*> _instance;
 	DcType _dcType = DcType::Regular;
 
@@ -215,21 +224,28 @@ private:
 	crl::time _waitForConnected = 0;
 	crl::time _firstSentAt = -1;
 
-	QVector<MTPlong> _ackRequestData;
-	QVector<MTPlong> _resendRequestData;
-
 	mtpPingId _pingId = 0;
 	mtpPingId _pingIdToSend = 0;
 	crl::time _pingSendAt = 0;
 	mtpMsgId _pingMsgId = 0;
 	base::Timer _pingSender;
+	base::Timer _checkSentRequestsTimer;
 
 	bool _finished = false;
 
-	AuthKeyPtr _temporaryKey;
-	uint64 _keyId = 0;
 	std::shared_ptr<SessionData> _sessionData;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
+	AuthKeyPtr _temporaryKey;
+	uint64 _keyId = 0;
+	uint64 _sessionId = 0;
+	uint64 _sessionSalt = 0;
+	uint32 _messagesCounter = 0;
+	bool _sessionMarkedAsStarted = false;
+
+	QVector<MTPlong> _ackRequestData;
+	QVector<MTPlong> _resendRequestData;
+	base::flat_set<mtpMsgId> _stateRequestData;
+	details::ReceivedIdsManager _receivedMessageIds;
 
 	std::unique_ptr<details::BoundKeyCreator> _keyCreator;
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.cpp
new file mode 100644
index 000000000..28e6ad518
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.cpp
@@ -0,0 +1,54 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/details/mtproto_received_ids_manager.h"
+
+namespace MTP::details {
+
+bool ReceivedIdsManager::registerMsgId(mtpMsgId msgId, bool needAck) {
+	const auto i = _idsNeedAck.find(msgId);
+	if (i == _idsNeedAck.end()) {
+		if (_idsNeedAck.size() < kIdsBufferSize || msgId > min()) {
+			_idsNeedAck.emplace(msgId, needAck);
+			return true;
+		}
+		MTP_LOG(-1, ("No need to handle - %1 < min = %2").arg(msgId).arg(min()));
+	} else {
+		MTP_LOG(-1, ("No need to handle - %1 already is in map").arg(msgId));
+	}
+	return false;
+}
+
+mtpMsgId ReceivedIdsManager::min() const {
+	return _idsNeedAck.empty() ? 0 : _idsNeedAck.begin()->first;
+}
+
+mtpMsgId ReceivedIdsManager::max() const {
+	auto end = _idsNeedAck.end();
+	return _idsNeedAck.empty() ? 0 : (--end)->first;
+}
+
+ReceivedIdsManager::State ReceivedIdsManager::lookup(mtpMsgId msgId) const {
+	auto i = _idsNeedAck.find(msgId);
+	if (i == _idsNeedAck.end()) {
+		return State::NotFound;
+	}
+	return i->second ? State::NeedsAck : State::NoAckNeeded;
+}
+
+void ReceivedIdsManager::shrink() {
+	auto size = _idsNeedAck.size();
+	while (size-- > kIdsBufferSize) {
+		_idsNeedAck.erase(_idsNeedAck.begin());
+	}
+}
+
+void ReceivedIdsManager::clear() {
+	_idsNeedAck.clear();
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.h b/Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.h
new file mode 100644
index 000000000..2a8d6a57a
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_received_ids_manager.h
@@ -0,0 +1,38 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/flat_map.h"
+
+namespace MTP::details {
+
+// Received msgIds and wereAcked msgIds count stored.
+inline constexpr auto kIdsBufferSize = 400;
+
+class ReceivedIdsManager final {
+public:
+	enum class State {
+		NotFound,
+		NeedsAck,
+		NoAckNeeded,
+	};
+
+	bool registerMsgId(mtpMsgId msgId, bool needAck);
+	[[nodiscard]] mtpMsgId min() const;
+	[[nodiscard]] mtpMsgId max() const;
+	[[nodiscard]] State lookup(mtpMsgId msgId) const;
+
+	void shrink();
+	void clear();
+
+private:
+	base::flat_map<mtpMsgId, bool> _idsNeedAck;
+
+};
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index dc400e8b6..3dacb252a 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -100,6 +100,7 @@ public:
 	void onStateChange(ShiftedDcId shiftedDcId, int32 state);
 	void onSessionReset(ShiftedDcId shiftedDcId);
 
+	// Thread-safe.
 	void clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids);
 
 	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 0504cb045..64677c4ab 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -17,28 +17,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace MTP {
 namespace internal {
-namespace {
-
-// How much time passed from send till we resend request or check its state.
-constexpr auto kCheckResendTimeout = crl::time(10000);
-
-// How much time to wait for some more requests,
-// when resending request or checking its state.
-constexpr auto kCheckResendWaiting = crl::time(1000);
-
-// Container lives 10 minutes in haveSent map.
-constexpr auto kContainerLives = 600;
-
-QString LogIds(const QVector<uint64> &ids) {
-	if (!ids.size()) return "[]";
-	auto idsStr = QString("[%1").arg(*ids.cbegin());
-	for (const auto id : ids) {
-		idsStr += QString(", %2").arg(id);
-	}
-	return idsStr + "]";
-}
-
-} // namespace
 
 ConnectionOptions::ConnectionOptions(
 	const QString &systemLangCode,
@@ -72,53 +50,6 @@ void SessionData::withSession(Callback &&callback) {
 	}
 }
 
-bool SessionData::setCurrentKeyId(uint64 keyId) {
-	QWriteLocker locker(&_lock);
-	if (_keyId == keyId) {
-		return false;
-	}
-	_keyId = keyId;
-
-	DEBUG_LOG(("MTP Info: auth key set in SessionData, id %1").arg(keyId));
-
-	changeSessionIdLocked();
-	return true;
-}
-
-void SessionData::changeSessionId() {
-	QWriteLocker locker(&_lock);
-	changeSessionIdLocked();
-}
-
-void SessionData::changeSessionIdLocked() {
-	auto sessionId = _sessionId;
-	do {
-		sessionId = openssl::RandomValue<uint64>();
-	} while (_sessionId == sessionId);
-
-	DEBUG_LOG(("MTP Info: setting server_session: %1").arg(sessionId));
-
-	_sessionId = sessionId;
-	_messagesSent = 0;
-	_sessionMarkedAsStarted = false;
-}
-
-uint32 SessionData::nextRequestSeqNumber(bool needAck) {
-	QWriteLocker locker(&_lock);
-	auto result = _messagesSent;
-	_messagesSent += (needAck ? 1 : 0);
-	return result * 2 + (needAck ? 1 : 0);
-}
-
-bool SessionData::markSessionAsStarted() {
-	QWriteLocker locker(&_lock);
-	if (_sessionMarkedAsStarted) {
-		return false;
-	}
-	_sessionMarkedAsStarted = true;
-	return true;
-}
-
 void SessionData::setKeyForCheck(const AuthKeyPtr &key) {
 	_dcKeyForCheck = key;
 }
@@ -173,10 +104,6 @@ void SessionData::clearForNewKey(not_null<Instance*> instance) {
 		QWriteLocker locker(wereAckedMutex());
 		_wereAcked.clear();
 	}
-	{
-		QWriteLocker locker(receivedIdsMutex());
-		_receivedIds.clear();
-	}
 	instance->clearCallbacksDelayed(std::move(clearCallbacks));
 }
 
@@ -291,7 +218,6 @@ Session::Session(
 , _ownedDc(dc ? nullptr : std::make_unique<Dcenter>(shiftedDcId, nullptr))
 , _dc(dc ? dc : _ownedDc.get())
 , _data(std::make_shared<SessionData>(this))
-, _timeouter([=] { checkRequestsByTimer(); })
 , _sender([=] { needToResumeAndSend(); }) {
 	_timeouter.callEach(1000);
 	refreshOptions();
@@ -459,60 +385,6 @@ bool Session::sharedDc() const {
 	return (_ownedDc == nullptr);
 }
 
-void Session::checkRequestsByTimer() {
-	QVector<mtpMsgId> removingIds; // remove very old (10 minutes) containers and resend requests
-	QVector<mtpMsgId> stateRequestIds;
-
-	{
-		QReadLocker locker(_data->haveSentMutex());
-		auto &haveSent = _data->haveSentMap();
-		const auto haveSentCount = haveSent.size();
-		auto ms = crl::now();
-		for (auto i = haveSent.begin(), e = haveSent.end(); i != e; ++i) {
-			auto &req = i.value();
-			if (req->msDate > 0) {
-				if (req->msDate + kCheckResendTimeout < ms) { // need to resend or check state
-					req->msDate = ms;
-					stateRequestIds.reserve(haveSentCount);
-					stateRequestIds.push_back(i.key());
-				}
-			} else if (base::unixtime::now()
-					> int32(i.key() >> 32) + kContainerLives) {
-				removingIds.reserve(haveSentCount);
-				removingIds.push_back(i.key());
-			}
-		}
-	}
-
-	if (stateRequestIds.size()) {
-		DEBUG_LOG(("MTP Info: requesting state of msgs: %1").arg(LogIds(stateRequestIds)));
-		{
-			QWriteLocker locker(_data->stateRequestMutex());
-			for (uint32 i = 0, l = stateRequestIds.size(); i < l; ++i) {
-				_data->stateRequestMap().insert(stateRequestIds[i], true);
-			}
-		}
-		sendAnything(kCheckResendWaiting);
-	}
-	if (!removingIds.isEmpty()) {
-		auto clearCallbacks = std::vector<RPCCallbackClear>();
-		{
-			QWriteLocker locker(_data->haveSentMutex());
-			auto &haveSent = _data->haveSentMap();
-			for (uint32 i = 0, l = removingIds.size(); i < l; ++i) {
-				auto j = haveSent.find(removingIds[i]);
-				if (j != haveSent.cend()) {
-					if (j.value()->requestId) {
-						clearCallbacks.push_back(j.value()->requestId);
-					}
-					haveSent.erase(j);
-				}
-			}
-		}
-		_instance->clearCallbacksDelayed(std::move(clearCallbacks));
-	}
-}
-
 void Session::connectionStateChange(int newState) {
 	_instance->onStateChange(_shiftedDcId, newState);
 }
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index b3034dcc8..2508e1cc8 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -21,9 +21,6 @@ using AuthKeyPtr = std::shared_ptr<AuthKey>;
 
 namespace internal {
 
-// Received msgIds and wereAcked msgIds count stored.
-constexpr auto kIdsBufferSize = 400;
-
 class Dcenter;
 class Connection;
 
@@ -45,60 +42,6 @@ public:
 
 };
 
-class ReceivedMsgIds {
-public:
-	bool registerMsgId(mtpMsgId msgId, bool needAck) {
-		auto i = _idsNeedAck.constFind(msgId);
-		if (i == _idsNeedAck.cend()) {
-			if (_idsNeedAck.size() < kIdsBufferSize || msgId > min()) {
-				_idsNeedAck.insert(msgId, needAck);
-				return true;
-			}
-			MTP_LOG(-1, ("No need to handle - %1 < min = %2").arg(msgId).arg(min()));
-		} else {
-			MTP_LOG(-1, ("No need to handle - %1 already is in map").arg(msgId));
-		}
-		return false;
-	}
-
-	mtpMsgId min() const {
-		return _idsNeedAck.isEmpty() ? 0 : _idsNeedAck.cbegin().key();
-	}
-
-	mtpMsgId max() const {
-		auto end = _idsNeedAck.cend();
-		return _idsNeedAck.isEmpty() ? 0 : (--end).key();
-	}
-
-	void shrink() {
-		auto size = _idsNeedAck.size();
-		while (size-- > kIdsBufferSize) {
-			_idsNeedAck.erase(_idsNeedAck.begin());
-		}
-	}
-
-	enum class State {
-		NotFound,
-		NeedsAck,
-		NoAckNeeded,
-	};
-	State lookup(mtpMsgId msgId) const {
-		auto i = _idsNeedAck.constFind(msgId);
-		if (i == _idsNeedAck.cend()) {
-			return State::NotFound;
-		}
-		return i.value() ? State::NeedsAck : State::NoAckNeeded;
-	}
-
-	void clear() {
-		_idsNeedAck.clear();
-	}
-
-private:
-	QMap<mtpMsgId, bool> _idsNeedAck;
-
-};
-
 using SerializedMessage = mtpBuffer;
 
 inline bool ResponseNeedsAck(const SerializedMessage &response) {
@@ -140,31 +83,16 @@ public:
 	SessionData(not_null<Session*> creator) : _owner(creator) {
 	}
 
-	bool setCurrentKeyId(uint64 keyId);
-	void changeSessionId();
-	[[nodiscard]] uint64 getSessionId() const {
-		QReadLocker locker(&_lock);
-		return _sessionId;
-	}
 	void notifyConnectionInited(const ConnectionOptions &options);
 	void setConnectionOptions(ConnectionOptions options) {
-		QWriteLocker locker(&_lock);
+		QWriteLocker locker(&_optionsLock);
 		_options = options;
 	}
 	[[nodiscard]] ConnectionOptions connectionOptions() const {
-		QReadLocker locker(&_lock);
+		QReadLocker locker(&_optionsLock);
 		return _options;
 	}
 
-	void setSalt(uint64 salt) {
-		QWriteLocker locker(&_lock);
-		_salt = salt;
-	}
-	[[nodiscard]] uint64 getSalt() const {
-		QReadLocker locker(&_lock);
-		return _salt;
-	}
-
 	[[nodiscard]] const AuthKeyPtr &getKeyForCheck() const {
 		return _dcKeyForCheck;
 	}
@@ -182,15 +110,9 @@ public:
 	not_null<QReadWriteLock*> wereAckedMutex() const {
 		return &_wereAckedLock;
 	}
-	not_null<QReadWriteLock*> receivedIdsMutex() const {
-		return &_receivedIdsLock;
-	}
 	not_null<QReadWriteLock*> haveReceivedMutex() const {
 		return &_haveReceivedLock;
 	}
-	not_null<QReadWriteLock*> stateRequestMutex() const {
-		return &_stateRequestLock;
-	}
 
 	PreRequestMap &toSendMap() {
 		return _toSend;
@@ -210,12 +132,6 @@ public:
 	const RequestIdsMap &toResendMap() const {
 		return _toResend;
 	}
-	ReceivedMsgIds &receivedIdsSet() {
-		return _receivedIds;
-	}
-	const ReceivedMsgIds &receivedIdsSet() const {
-		return _receivedIds;
-	}
 	RequestIdsMap &wereAckedMap() {
 		return _wereAcked;
 	}
@@ -234,21 +150,12 @@ public:
 	const QList<SerializedMessage> &haveReceivedUpdates() const {
 		return _receivedUpdates;
 	}
-	QMap<mtpMsgId, bool> &stateRequestMap() {
-		return _stateRequest;
-	}
-	const QMap<mtpMsgId, bool> &stateRequestMap() const {
-		return _stateRequest;
-	}
 
 	// Warning! Valid only in constructor, _owner is guaranteed != null.
 	[[nodiscard]] not_null<Session*> owner() {
 		return _owner;
 	}
 
-	[[nodiscard]] bool markSessionAsStarted();
-	[[nodiscard]] uint32 nextRequestSeqNumber(bool needAck);
-
 	void clearForNewKey(not_null<Instance*> instance);
 
 	// Connection -> Session interface.
@@ -277,17 +184,9 @@ public:
 	void detach();
 
 private:
-	void changeSessionIdLocked();
-
 	template <typename Callback>
 	void withSession(Callback &&callback);
 
-	uint64 _keyId = 0;
-	uint64 _sessionId = 0;
-	uint64 _salt = 0;
-	uint32 _messagesSent = 0;
-	bool _sessionMarkedAsStarted = false;
-
 	Session *_owner = nullptr;
 	mutable QMutex _ownerMutex;
 
@@ -297,22 +196,18 @@ private:
 	PreRequestMap _toSend; // map of request_id -> request, that is waiting to be sent
 	RequestMap _haveSent; // map of msg_id -> request, that was sent, msDate = 0 for msgs_state_req (no resend / state req), msDate = 0, seqNo = 0 for containers
 	RequestIdsMap _toResend; // map of msg_id -> request_id, that request_id -> request lies in toSend and is waiting to be resent
-	ReceivedMsgIds _receivedIds; // set of received msg_id's, for checking new msg_ids
 	RequestIdsMap _wereAcked; // map of msg_id -> request_id, this msg_ids already were acked or do not need ack
-	QMap<mtpMsgId, bool> _stateRequest; // set of msg_id's, whose state should be requested
 
 	QMap<mtpRequestId, SerializedMessage> _receivedResponses; // map of request_id -> response that should be processed in the main thread
 	QList<SerializedMessage> _receivedUpdates; // list of updates that should be processed in the main thread
 
 	// mutexes
-	mutable QReadWriteLock _lock;
+	mutable QReadWriteLock _optionsLock;
 	mutable QReadWriteLock _toSendLock;
 	mutable QReadWriteLock _haveSentLock;
 	mutable QReadWriteLock _toResendLock;
-	mutable QReadWriteLock _receivedIdsLock;
 	mutable QReadWriteLock _wereAckedLock;
 	mutable QReadWriteLock _haveReceivedLock;
-	mutable QReadWriteLock _stateRequestLock;
 
 };
 
@@ -388,7 +283,6 @@ signals:
 
 private:
 	[[nodiscard]] bool sharedDc() const;
-	void checkRequestsByTimer();
 	void watchDcKeyChanges();
 
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index 93a02d331..4b01766a2 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -42,6 +42,8 @@
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.h',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.cpp',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.h',
+      '<(src_loc)/mtproto/details/mtproto_received_ids_manager.cpp',
+      '<(src_loc)/mtproto/details/mtproto_received_ids_manager.h',
       '<(src_loc)/mtproto/mtproto_abstract_socket.cpp',
       '<(src_loc)/mtproto/mtproto_abstract_socket.h',
       '<(src_loc)/mtproto/mtproto_auth_key.cpp',

From 4c24ec772553857e40662fdd5c67390f01ae316b Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 14:50:19 +0300
Subject: [PATCH 37/91] Fix keys destruction on logout.

---
 Telegram/SourceFiles/mtproto/connection.cpp | 63 +++++++++++----------
 Telegram/SourceFiles/mtproto/connection.h   |  4 +-
 2 files changed, 36 insertions(+), 31 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 9c206ff27..83474c4cf 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -608,7 +608,7 @@ void ConnectionPrivate::tryToSend() {
 		}
 		if (_keyCreator && _keyCreator->bindReadyToRequest()) {
 			bindDcKeyRequest = _keyCreator->prepareBindRequest(
-				_temporaryKey,
+				_encryptionKey,
 				_sessionId);
 
 			// This is a special request with msgId used inside the message
@@ -623,7 +623,7 @@ void ConnectionPrivate::tryToSend() {
 		//			_shiftedDcId,
 		//			keyForCheck);
 		//		bindDcKeyRequest = _keyChecker->prepareRequest(
-		//			_temporaryKey,
+		//			_encryptionKey,
 		//			_sessionId);
 
 		//		// This is a special request with msgId used inside the message
@@ -1201,7 +1201,7 @@ void ConnectionPrivate::requestCDNConfig() {
 }
 
 void ConnectionPrivate::handleReceived() {
-	Expects(_temporaryKey != nullptr);
+	Expects(_encryptionKey != nullptr);
 
 	onReceivedSome();
 
@@ -1235,9 +1235,9 @@ void ConnectionPrivate::handleReceived() {
 		auto msgKey = *(MTPint128*)(ints + 2);
 
 #ifdef TDESKTOP_MTPROTO_OLD
-		aesIgeDecrypt_oldmtp(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _temporaryKey, msgKey);
+		aesIgeDecrypt_oldmtp(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _encryptionKey, msgKey);
 #else // TDESKTOP_MTPROTO_OLD
-		aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _temporaryKey, msgKey);
+		aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, _encryptionKey, msgKey);
 #endif // TDESKTOP_MTPROTO_OLD
 
 		auto decryptedInts = reinterpret_cast<const mtpPrime*>(decryptedBuffer.constData());
@@ -1284,7 +1284,7 @@ void ConnectionPrivate::handleReceived() {
 
 		SHA256_CTX msgKeyLargeContext;
 		SHA256_Init(&msgKeyLargeContext);
-		SHA256_Update(&msgKeyLargeContext, _temporaryKey->partForMsgKey(false), 32);
+		SHA256_Update(&msgKeyLargeContext, _encryptionKey->partForMsgKey(false), 32);
 		SHA256_Update(&msgKeyLargeContext, decryptedInts, encryptedBytesCount);
 		SHA256_Final(sha256Buffer.data(), &msgKeyLargeContext);
 
@@ -1350,7 +1350,7 @@ void ConnectionPrivate::handleReceived() {
 		auto from = decryptedInts + kEncryptedHeaderIntsCount;
 		auto end = from + (messageLength / kIntSize);
 		auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
-		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end) + QString(" (keyId:%1)").arg(_temporaryKey->keyId()));
+		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end) + QString(" (keyId:%1)").arg(_encryptionKey->keyId()));
 
 		if (_receivedMessageIds.registerMsgId(msgId, needAck)) {
 			res = handleOneReceived(from, end, msgId, serverTime, serverSalt, badTime);
@@ -1859,7 +1859,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				response);
 			if (result == DcKeyBindState::Success) {
 				_sessionData->releaseKeyCreationOnDone(
-					_temporaryKey,
+					_encryptionKey,
 					base::take(_keyCreator)->bindPersistentKey());
 				_sessionData->queueNeedToResumeAndSend();
 				return HandleResult::Success;
@@ -2307,13 +2307,15 @@ void ConnectionPrivate::removeTestConnection(
 void ConnectionPrivate::checkAuthKey() {
 	if (_keyId) {
 		authKeyChecked();
+	} else if (_instance->isKeysDestroyer()) {
+		applyAuthKey(_sessionData->getPersistentKey());
 	} else {
 		applyAuthKey(_sessionData->getTemporaryKey());
 	}
 }
 
 void ConnectionPrivate::updateAuthKey() {
-	if (_keyCreator) {
+	if (_instance->isKeysDestroyer() || _keyCreator) {
 		return;
 	}
 
@@ -2331,9 +2333,9 @@ void ConnectionPrivate::setCurrentKeyId(uint64 newKeyId) {
 	changeSessionId();
 }
 
-void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
-	_temporaryKey = std::move(temporaryKey);
-	const auto newKeyId = _temporaryKey ? _temporaryKey->keyId() : 0;
+void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&encryptionKey) {
+	_encryptionKey = std::move(encryptionKey);
+	const auto newKeyId = _encryptionKey ? _encryptionKey->keyId() : 0;
 	if (_keyId) {
 		if (_keyId == newKeyId) {
 			return;
@@ -2374,7 +2376,9 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&temporaryKey) {
 }
 
 void ConnectionPrivate::tryAcquireKeyCreation() {
-	if (_keyCreator || !_sessionData->acquireKeyCreation()) {
+	if (_instance->isKeysDestroyer()
+		|| _keyCreator
+		|| !_sessionData->acquireKeyCreation()) {
 		return;
 	}
 
@@ -2479,25 +2483,26 @@ void ConnectionPrivate::handleError(int errorCode) {
 	_waitForConnectedTimer.cancel();
 
 	if (errorCode == -404) {
-		if (_instance->isKeysDestroyer()) {
-			LOG(("MTP Info: -404 error received in destroyer %1, assuming key was destroyed.").arg(_shiftedDcId));
-			_instance->checkIfKeyWasDestroyed(_shiftedDcId);
-			return;
-		} else if (_temporaryKey) {
-			LOG(("MTP Info: -404 error received in %1 with temporary key, assuming it was destroyed.").arg(_shiftedDcId));
-			destroyTemporaryKey();
-		}
+		destroyTemporaryKey();
+	} else {
+		MTP_LOG(_shiftedDcId, ("Restarting after error in connection, error code: %1...").arg(errorCode));
+		return restart();
 	}
-	MTP_LOG(_shiftedDcId, ("Restarting after error in connection, error code: %1...").arg(errorCode));
-	return restart();
 }
 
 void ConnectionPrivate::destroyTemporaryKey() {
+	if (_instance->isKeysDestroyer()) {
+		LOG(("MTP Info: -404 error received in destroyer %1, assuming key was destroyed.").arg(_shiftedDcId));
+		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
+		return;
+	}
+	LOG(("MTP Info: -404 error received in %1 with temporary key, assuming it was destroyed.").arg(_shiftedDcId));
 	releaseKeyCreationOnFail();
-	if (_temporaryKey) {
-		_sessionData->destroyTemporaryKey(_temporaryKey->keyId());
+	if (_encryptionKey) {
+		_sessionData->destroyTemporaryKey(_encryptionKey->keyId());
 	}
 	applyAuthKey(nullptr);
+	restart();
 }
 
 bool ConnectionPrivate::sendSecureRequest(
@@ -2524,7 +2529,7 @@ bool ConnectionPrivate::sendSecureRequest(
 	memcpy(request->data() + 2, &_sessionId, 2 * sizeof(mtpPrime));
 
 	auto from = request->constData() + 4;
-	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize) + QString(" (keyId:%1)").arg(_temporaryKey->keyId()));
+	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize) + QString(" (keyId:%1)").arg(_encryptionKey->keyId()));
 
 #ifdef TDESKTOP_MTPROTO_OLD
 	uint32 padding = fullSize - 4 - messageSize;
@@ -2544,7 +2549,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		request->constData(),
 		&packet[prefix],
 		fullSize * sizeof(mtpPrime),
-		_temporaryKey,
+		_encryptionKey,
 		msgKey);
 #else // TDESKTOP_MTPROTO_OLD
 	uchar encryptedSHA256[32];
@@ -2552,7 +2557,7 @@ bool ConnectionPrivate::sendSecureRequest(
 
 	SHA256_CTX msgKeyLargeContext;
 	SHA256_Init(&msgKeyLargeContext);
-	SHA256_Update(&msgKeyLargeContext, _temporaryKey->partForMsgKey(true), 32);
+	SHA256_Update(&msgKeyLargeContext, _encryptionKey->partForMsgKey(true), 32);
 	SHA256_Update(&msgKeyLargeContext, request->constData(), fullSize * sizeof(mtpPrime));
 	SHA256_Final(encryptedSHA256, &msgKeyLargeContext);
 
@@ -2564,7 +2569,7 @@ bool ConnectionPrivate::sendSecureRequest(
 		request->constData(),
 		&packet[prefix],
 		fullSize * sizeof(mtpPrime),
-		_temporaryKey,
+		_encryptionKey,
 		msgKey);
 #endif // TDESKTOP_MTPROTO_OLD
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 77e7debc0..cc303d329 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -188,7 +188,7 @@ private:
 	void destroyTemporaryKey();
 	void clearUnboundKeyCreator();
 	void releaseKeyCreationOnFail();
-	void applyAuthKey(AuthKeyPtr &&temporaryKey);
+	void applyAuthKey(AuthKeyPtr &&encryptionKey);
 
 	void setCurrentKeyId(uint64 newKeyId);
 	void changeSessionId();
@@ -235,7 +235,7 @@ private:
 
 	std::shared_ptr<SessionData> _sessionData;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
-	AuthKeyPtr _temporaryKey;
+	AuthKeyPtr _encryptionKey;
 	uint64 _keyId = 0;
 	uint64 _sessionId = 0;
 	uint64 _sessionSalt = 0;

From 4edfd4804fdf8160ae5df840e176133bd79191a3 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 16:33:45 +0300
Subject: [PATCH 38/91] Fix destroyed key clearing.

---
 Telegram/SourceFiles/main/main_account.cpp    | 12 +--
 Telegram/SourceFiles/main/main_account.h      |  1 +
 Telegram/SourceFiles/mtproto/connection.cpp   | 43 +++++---
 Telegram/SourceFiles/mtproto/connection.h     |  1 +
 Telegram/SourceFiles/mtproto/core_types.h     |  1 -
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 99 +++++++------------
 Telegram/SourceFiles/mtproto/mtp_instance.h   |  9 +-
 .../SourceFiles/mtproto/mtproto_auth_key.cpp  | 10 +-
 .../SourceFiles/mtproto/mtproto_auth_key.h    |  5 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 62 ++++--------
 Telegram/SourceFiles/mtproto/session.h        | 12 +--
 11 files changed, 108 insertions(+), 147 deletions(-)

diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index 0f98bb2ea..5fbbd0b64 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -378,13 +378,12 @@ void Account::startMtp() {
 
 
 void Account::logOut() {
+	if (_loggingOut) {
+		return;
+	}
+	_loggingOut = true;
 	if (_mtp) {
-		_mtp->logout(::rpcDone([=] {
-			loggedOut();
-		}), ::rpcFail([=] {
-			loggedOut();
-			return true;
-		}));
+		_mtp->logout([=] { loggedOut(); });
 	} else {
 		// We log out because we've forgotten passcode.
 		loggedOut();
@@ -399,6 +398,7 @@ void Account::forcedLogOut() {
 }
 
 void Account::loggedOut() {
+	_loggingOut = false;
 	if (Global::LocalPasscode()) {
 		Global::SetLocalPasscode(false);
 		Global::RefLocalPasscodeChanged().notify();
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 64aff4a1c..8783e9a08 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -97,6 +97,7 @@ private:
 	std::unique_ptr<Settings> _storedSettings;
 	MTP::Instance::Config _mtpConfig;
 	MTP::AuthKeysList _mtpKeysToDestroy;
+	bool _loggingOut = false;
 
 	rpl::lifetime _lifetime;
 
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 83474c4cf..1aec169cd 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -40,6 +40,7 @@ constexpr auto kTemporaryExpiresIn = TimeId(10);
 constexpr auto kBindKeyAdditionalExpiresTimeout = TimeId(30);
 constexpr auto kTestModeDcIdShift = 10000;
 constexpr auto kCheckSentRequestsEach = 1 * crl::time(1000);
+constexpr auto kKeyOldEnoughForDestroy = 60 * crl::time(1000);
 
 // If we can't connect for this time we will ask _instance to update config.
 constexpr auto kRequestConfigTimeout = 8 * crl::time(1000);
@@ -997,7 +998,7 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 	if (_testConnections.empty()) {
 		if (_instance->isKeysDestroyer()) {
 			LOG(("MTP Error: DC %1 options for not found for auth key destruction!").arg(_shiftedDcId));
-			_instance->checkIfKeyWasDestroyed(_shiftedDcId);
+			_instance->keyWasPossiblyDestroyed(_shiftedDcId);
 			return;
 		} else if (afterConfig) {
 			LOG(("MTP Error: DC %1 options for not found right after config load!").arg(_shiftedDcId));
@@ -1857,19 +1858,19 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			const auto result = _keyCreator->handleBindResponse(
 				reqMsgId,
 				response);
-			if (result == DcKeyBindState::Success) {
+			switch (result) {
+			case DcKeyBindState::Success:
 				_sessionData->releaseKeyCreationOnDone(
 					_encryptionKey,
 					base::take(_keyCreator)->bindPersistentKey());
 				_sessionData->queueNeedToResumeAndSend();
 				return HandleResult::Success;
-			} else if (result == DcKeyBindState::Failed
-				|| result == DcKeyBindState::DefinitelyDestroyed) {
-				// #TODO maybe destroy persistent key
-				// crl::on_main(
-				//   _keyCreator->bindPersistentKey()->setLastCheckTime(crl::now());
-				//   instance->keyDestroyedOnServer(BareDcId(shiftedDcId), base::take(_keyCreator)->bindPersistentKey()->keyId());
-				// )
+			case DcKeyBindState::DefinitelyDestroyed:
+				if (destroyOldEnoughPersistentKey()) {
+					return HandleResult::DestroyTemporaryKey;
+				}
+				[[fallthrough]];
+			case DcKeyBindState::Failed:
 				_sessionData->queueNeedToResumeAndSend();
 				return HandleResult::Success;
 			}
@@ -2362,7 +2363,7 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 	if (_instance->isKeysDestroyer()) {
 		// We are here to destroy an old key, so we're done.
 		LOG(("MTP Error: No key %1 in updateAuthKey() for destroying.").arg(_shiftedDcId));
-		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
+		_instance->keyWasPossiblyDestroyed(_shiftedDcId);
 	} else if (_keyCreator) {
 		DEBUG_LOG(("AuthKey Info: No key in updateAuthKey(), creating."));
 		_keyCreator->start(
@@ -2375,6 +2376,25 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 	}
 }
 
+bool ConnectionPrivate::destroyOldEnoughPersistentKey() {
+	Expects(_keyCreator != nullptr);
+
+	const auto key = _keyCreator->bindPersistentKey();
+	Assert(key != nullptr);
+
+	const auto created = key->creationTime();
+	if (created > 0 && crl::now() - created < kKeyOldEnoughForDestroy) {
+		return false;
+	}
+	const auto instance = _instance;
+	const auto shiftedDcId = _shiftedDcId;
+	const auto keyId = key->keyId();
+	InvokeQueued(instance, [=] {
+		instance->keyDestroyedOnServer(shiftedDcId, keyId);
+	});
+	return true;
+}
+
 void ConnectionPrivate::tryAcquireKeyCreation() {
 	if (_instance->isKeysDestroyer()
 		|| _keyCreator
@@ -2436,7 +2456,6 @@ void ConnectionPrivate::tryAcquireKeyCreation() {
 		onReceivedSome();
 	};
 
-	//	const auto check = (GetDcIdShift(_shiftedDcId) == kCheckKeyDcShift); // #TODO remove kCheckKeyDcShift
 	auto request = DcKeyRequest();
 	request.persistentNeeded = !_sessionData->getPersistentKey();
 	request.temporaryExpiresIn = kTemporaryExpiresIn;
@@ -2493,7 +2512,7 @@ void ConnectionPrivate::handleError(int errorCode) {
 void ConnectionPrivate::destroyTemporaryKey() {
 	if (_instance->isKeysDestroyer()) {
 		LOG(("MTP Info: -404 error received in destroyer %1, assuming key was destroyed.").arg(_shiftedDcId));
-		_instance->checkIfKeyWasDestroyed(_shiftedDcId);
+		_instance->keyWasPossiblyDestroyed(_shiftedDcId);
 		return;
 	}
 	LOG(("MTP Info: -404 error received in %1 with temporary key, assuming it was destroyed.").arg(_shiftedDcId));
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index cc303d329..fa8ec88cd 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -189,6 +189,7 @@ private:
 	void clearUnboundKeyCreator();
 	void releaseKeyCreationOnFail();
 	void applyAuthKey(AuthKeyPtr &&encryptionKey);
+	bool destroyOldEnoughPersistentKey();
 
 	void setCurrentKeyId(uint64 newKeyId);
 	void changeSessionId();
diff --git a/Telegram/SourceFiles/mtproto/core_types.h b/Telegram/SourceFiles/mtproto/core_types.h
index 58db5caa4..37c84a16d 100644
--- a/Telegram/SourceFiles/mtproto/core_types.h
+++ b/Telegram/SourceFiles/mtproto/core_types.h
@@ -42,7 +42,6 @@ constexpr auto kLogoutDcShift = 0x02;
 constexpr auto kUpdaterDcShift = 0x03;
 constexpr auto kExportDcShift = 0x04;
 constexpr auto kExportMediaDcShift = 0x05;
-constexpr auto kCheckKeyDcShift = 0x06;
 constexpr auto kMaxMediaDcCount = 0x10;
 constexpr auto kBaseDownloadDcShift = 0x10;
 constexpr auto kBaseUploadDcShift = 0x20;
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index f4c0a22e9..20fa3e1a5 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -95,7 +95,7 @@ public:
 	void killSession(ShiftedDcId shiftedDcId);
 	void stopSession(ShiftedDcId shiftedDcId);
 	void reInitConnection(DcId dcId);
-	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
+	void logout(Fn<void()> done);
 
 	not_null<Dcenter*> getDcById(ShiftedDcId shiftedDcId);
 	Dcenter *findDc(ShiftedDcId shiftedDcId);
@@ -154,11 +154,10 @@ public:
 	}
 
 	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
-	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
+	void keyWasPossiblyDestroyed(ShiftedDcId shiftedDcId);
 	void performKeyDestroy(ShiftedDcId shiftedDcId);
 	void completedKeyDestroy(ShiftedDcId shiftedDcId);
-	void checkMainDcKey();
-	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
+	void keyDestroyedOnServer(ShiftedDcId shiftedDcId, uint64 keyId);
 
 	void prepareToDestroy();
 
@@ -609,10 +608,13 @@ void Instance::Private::reInitConnection(DcId dcId) {
 	}
 }
 
-void Instance::Private::logout(
-		RPCDoneHandlerPtr onDone,
-		RPCFailHandlerPtr onFail) {
-	_instance->send(MTPauth_LogOut(), std::move(onDone), std::move(onFail));
+void Instance::Private::logout(Fn<void()> done) {
+	_instance->send(MTPauth_LogOut(), rpcDone([=] {
+		done();
+	}), rpcFail([=] {
+		done();
+		return true;
+	}));
 	logoutGuestDcs();
 }
 
@@ -1502,14 +1504,16 @@ Session *Instance::Private::findSession(ShiftedDcId shiftedDcId) {
 not_null<Session*> Instance::Private::startSession(ShiftedDcId shiftedDcId) {
 	Expects(BareDcId(shiftedDcId) != 0);
 
-	const auto dc = (GetDcIdShift(shiftedDcId) != kCheckKeyDcShift)
-		? getDcById(shiftedDcId).get()
-		: nullptr;
+	const auto dc = getDcById(shiftedDcId);
 	const auto result = _sessions.emplace(
 		shiftedDcId,
 		std::make_unique<Session>(_instance, shiftedDcId, dc)
 	).first->second.get();
 	result->start();
+	if (isKeysDestroyer()) {
+		scheduleKeyDestroy(shiftedDcId);
+	}
+
 	return result;
 }
 
@@ -1542,24 +1546,20 @@ void Instance::Private::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
 	}
 }
 
-void Instance::Private::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
+void Instance::Private::keyWasPossiblyDestroyed(ShiftedDcId shiftedDcId) {
+	Expects(isKeysDestroyer());
+
 	InvokeQueued(_instance, [=] {
-		if (isKeysDestroyer()) {
-			LOG(("MTP Info: checkIfKeyWasDestroyed on destroying key %1, "
-				"assuming it is destroyed.").arg(shiftedDcId));
-			completedKeyDestroy(shiftedDcId);
-		} else if (BareDcId(shiftedDcId) == mainDcId()) {
-			LOG(("MTP Info: checkIfKeyWasDestroyed for main dc %1, "
-				"checking.").arg(shiftedDcId));
-			checkMainDcKey();
-		}
+		LOG(("MTP Info: checkIfKeyWasDestroyed on destroying key %1, "
+			"assuming it is destroyed.").arg(shiftedDcId));
+		completedKeyDestroy(shiftedDcId);
 	});
 }
 
 void Instance::Private::performKeyDestroy(ShiftedDcId shiftedDcId) {
 	Expects(isKeysDestroyer());
 
-	_instance->send(MTPDestroy_auth_key(), rpcDone([this, shiftedDcId](const MTPDestroyAuthKeyRes &result) {
+	_instance->send(MTPDestroy_auth_key(), rpcDone([=](const MTPDestroyAuthKeyRes &result) {
 		switch (result.type()) {
 		case mtpc_destroy_auth_key_ok: LOG(("MTP Info: key %1 destroyed.").arg(shiftedDcId)); break;
 		case mtpc_destroy_auth_key_fail: {
@@ -1568,10 +1568,10 @@ void Instance::Private::performKeyDestroy(ShiftedDcId shiftedDcId) {
 		} break;
 		case mtpc_destroy_auth_key_none: LOG(("MTP Info: key %1 already destroyed.").arg(shiftedDcId)); break;
 		}
-		_instance->checkIfKeyWasDestroyed(shiftedDcId);
-	}), rpcFail([this, shiftedDcId](const RPCError &error) {
+		_instance->keyWasPossiblyDestroyed(shiftedDcId);
+	}), rpcFail([=](const RPCError &error) {
 		LOG(("MTP Error: key %1 destruction resulted in error: %2").arg(shiftedDcId).arg(error.type()));
-		_instance->checkIfKeyWasDestroyed(shiftedDcId);
+		_instance->keyWasPossiblyDestroyed(shiftedDcId);
 		return true;
 	}), shiftedDcId);
 }
@@ -1587,34 +1587,19 @@ void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 	}
 }
 
-void Instance::Private::checkMainDcKey() {
-	const auto id = mainDcId();
-	const auto shiftedDcId = ShiftDcId(id, kCheckKeyDcShift);
-	if (findSession(shiftedDcId)) {
-		return;
-	}
-	const auto i = _keysForWrite.find(id);
-	if (i == end(_keysForWrite)) {
-		return;
-	}
-	const auto lastCheckTime = i->second->lastCheckTime();
-	if (lastCheckTime > 0 && lastCheckTime + kCheckKeyEach >= crl::now()) {
-		return;
-	}
-	_instance->sendDcKeyCheck(shiftedDcId, i->second);
-}
-
-void Instance::Private::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
-	LOG(("Destroying key for dc: %1").arg(dcId));
-	if (const auto dc = findDc(dcId)) {
+void Instance::Private::keyDestroyedOnServer(
+		ShiftedDcId shiftedDcId,
+		uint64 keyId) {
+	LOG(("Destroying key for dc: %1").arg(shiftedDcId));
+	if (const auto dc = findDc(BareDcId(shiftedDcId))) {
 		if (dc->destroyConfirmedForgottenKey(keyId)) {
 			LOG(("Key destroyed!"));
-			dcPersistentKeyChanged(dcId, nullptr);
+			dcPersistentKeyChanged(BareDcId(shiftedDcId), nullptr);
 		} else {
 			LOG(("Key already is different."));
 		}
 	}
-	restart(dcId);
+	restart(shiftedDcId);
 }
 
 void Instance::Private::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
@@ -1758,8 +1743,8 @@ void Instance::reInitConnection(DcId dcId) {
 	_private->reInitConnection(dcId);
 }
 
-void Instance::logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail) {
-	_private->logout(onDone, onFail);
+void Instance::logout(Fn<void()> done) {
+	_private->logout(std::move(done));
 }
 
 void Instance::dcPersistentKeyChanged(
@@ -1857,16 +1842,12 @@ bool Instance::isKeysDestroyer() const {
 	return _private->isKeysDestroyer();
 }
 
-void Instance::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
-	_private->scheduleKeyDestroy(shiftedDcId);
+void Instance::keyWasPossiblyDestroyed(ShiftedDcId shiftedDcId) {
+	_private->keyWasPossiblyDestroyed(shiftedDcId);
 }
 
-void Instance::checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId) {
-	_private->checkIfKeyWasDestroyed(shiftedDcId);
-}
-
-void Instance::keyDestroyedOnServer(DcId dcId, uint64 keyId) {
-	_private->keyDestroyedOnServer(dcId, keyId);
+void Instance::keyDestroyedOnServer(ShiftedDcId shiftedDcId, uint64 keyId) {
+	_private->keyDestroyedOnServer(shiftedDcId, keyId);
 }
 
 void Instance::sendRequest(
@@ -1891,10 +1872,6 @@ void Instance::sendAnything(ShiftedDcId shiftedDcId, crl::time msCanWait) {
 	_private->getSession(shiftedDcId)->sendAnything(msCanWait);
 }
 
-void Instance::sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key) {
-	_private->getSession(shiftedDcId)->sendDcKeyCheck(key);
-}
-
 Instance::~Instance() {
 	_private->prepareToDestroy();
 }
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 3dacb252a..a59a96a9b 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -85,7 +85,7 @@ public:
 	void killSession(ShiftedDcId shiftedDcId);
 	void stopSession(ShiftedDcId shiftedDcId);
 	void reInitConnection(DcId dcId);
-	void logout(RPCDoneHandlerPtr onDone, RPCFailHandlerPtr onFail);
+	void logout(Fn<void()> done);
 
 	void unpaused();
 
@@ -110,12 +110,12 @@ public:
 	// return true if need to clean request data
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
 
+	// Thread-safe.
 	bool isKeysDestroyer() const;
-	void scheduleKeyDestroy(ShiftedDcId shiftedDcId);
-	void checkIfKeyWasDestroyed(ShiftedDcId shiftedDcId);
+	void keyWasPossiblyDestroyed(ShiftedDcId shiftedDcId);
 
 	// Main thread.
-	void keyDestroyedOnServer(DcId dcId, uint64 keyId);
+	void keyDestroyedOnServer(ShiftedDcId shiftedDcId, uint64 keyId);
 
 	void requestConfig();
 	void requestConfigIfOld();
@@ -128,7 +128,6 @@ public:
 	void connectionFinished(not_null<internal::Connection*> connection);
 
 	void sendAnything(ShiftedDcId shiftedDcId = 0, crl::time msCanWait = 0);
-	void sendDcKeyCheck(ShiftedDcId shiftedDcId, const AuthKeyPtr &key);
 
 	template <typename Request>
 	mtpRequestId send(
diff --git a/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
index 706d6bdca..c84d19a61 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_auth_key.cpp
@@ -19,7 +19,7 @@ AuthKey::AuthKey(Type type, DcId dcId, const Data &data)
 , _key(data) {
 	countKeyId();
 	if (type == Type::Generated || type == Type::Temporary) {
-		_lastCheckTime = crl::now();
+		_creationTime = crl::now();
 	}
 }
 
@@ -115,12 +115,8 @@ bool AuthKey::equals(const std::shared_ptr<AuthKey> &other) const {
 	return other ? (_key == other->_key) : false;
 }
 
-crl::time AuthKey::lastCheckTime() const {
-	return _lastCheckTime;
-}
-
-void AuthKey::setLastCheckTime(crl::time time) {
-	_lastCheckTime = time;
+crl::time AuthKey::creationTime() const {
+	return _creationTime;
 }
 
 TimeId AuthKey::expiresAt() const {
diff --git a/Telegram/SourceFiles/mtproto/mtproto_auth_key.h b/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
index 082d47310..31d0e3db3 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
+++ b/Telegram/SourceFiles/mtproto/mtproto_auth_key.h
@@ -44,8 +44,7 @@ public:
 	[[nodiscard]] bytes::const_span data() const;
 	[[nodiscard]] bool equals(const std::shared_ptr<AuthKey> &other) const;
 
-	[[nodiscard]] crl::time lastCheckTime() const;
-	void setLastCheckTime(crl::time time);
+	[[nodiscard]] crl::time creationTime() const; // > 0 if known.
 	[[nodiscard]] TimeId expiresAt() const;
 	void setExpiresAt(TimeId expiresAt);
 
@@ -58,7 +57,7 @@ private:
 	DcId _dcId = 0;
 	Data _key = { { gsl::byte{} } };
 	KeyId _keyId = 0;
-	crl::time _lastCheckTime = 0;
+	crl::time _creationTime = 0;
 	TimeId _expiresAt = 0;
 
 };
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 64677c4ab..5fb0b9e66 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -50,10 +50,6 @@ void SessionData::withSession(Callback &&callback) {
 	}
 }
 
-void SessionData::setKeyForCheck(const AuthKeyPtr &key) {
-	_dcKeyForCheck = key;
-}
-
 void SessionData::notifyConnectionInited(const ConnectionOptions &options) {
 	// #TODO race
 	const auto current = connectionOptions();
@@ -61,7 +57,10 @@ void SessionData::notifyConnectionInited(const ConnectionOptions &options) {
 		&& current.systemLangCode == _options.systemLangCode
 		&& current.langPackName == _options.langPackName
 		&& current.proxy == _options.proxy) {
-		owner()->notifyDcConnectionInited();
+		QMutexLocker lock(&_ownerMutex);
+		if (_owner) {
+			_owner->notifyDcConnectionInited();
+		}
 	}
 }
 
@@ -211,19 +210,16 @@ void SessionData::detach() {
 Session::Session(
 	not_null<Instance*> instance,
 	ShiftedDcId shiftedDcId,
-	Dcenter *dc)
+	not_null<Dcenter*> dc)
 : QObject()
 , _instance(instance)
 , _shiftedDcId(shiftedDcId)
-, _ownedDc(dc ? nullptr : std::make_unique<Dcenter>(shiftedDcId, nullptr))
-, _dc(dc ? dc : _ownedDc.get())
+, _dc(dc)
 , _data(std::make_shared<SessionData>(this))
 , _sender([=] { needToResumeAndSend(); }) {
 	_timeouter.callEach(1000);
 	refreshOptions();
-	if (sharedDc()) {
-		watchDcKeyChanges();
-	}
+	watchDcKeyChanges();
 }
 
 void Session::watchDcKeyChanges() {
@@ -240,9 +236,6 @@ void Session::watchDcKeyChanges() {
 void Session::start() {
 	_connection = std::make_unique<Connection>(_instance);
 	_connection->start(_data, _shiftedDcId);
-	if (_instance->isKeysDestroyer()) {
-		_instance->scheduleKeyDestroy(_shiftedDcId);
-	}
 }
 
 bool Session::rpcErrorOccured(
@@ -317,11 +310,6 @@ void Session::unpaused() {
 	}
 }
 
-void Session::sendDcKeyCheck(const AuthKeyPtr &key) {
-	_data->setKeyForCheck(key);
-	needToResumeAndSend();
-}
-
 void Session::sendAnything(crl::time msCanWait) {
 	if (_killed) {
 		DEBUG_LOG(("Session Error: can't send anything in a killed session"));
@@ -381,10 +369,6 @@ void Session::sendMsgsStateInfo(quint64 msgId, QByteArray data) {
 			MTP_msgs_state_info(MTP_long(msgId), MTP_bytes(data))));
 }
 
-bool Session::sharedDc() const {
-	return (_ownedDc == nullptr);
-}
-
 void Session::connectionStateChange(int newState) {
 	_instance->onStateChange(_shiftedDcId, newState);
 }
@@ -565,17 +549,15 @@ void Session::releaseKeyCreationOnDone(
 	_dc->releaseKeyCreationOnDone(temporaryKey, persistentKey);
 	_myKeyCreation = false;
 
-	if (sharedDc()) {
-		const auto dcId = _dc->id();
-		const auto instance = _instance;
-		InvokeQueued(instance, [=] {
-			if (persistentKey) {
-				instance->dcPersistentKeyChanged(dcId, persistentKey);
-			} else {
-				instance->dcTemporaryKeyChanged(dcId);
-			}
-		});
-	}
+	const auto dcId = _dc->id();
+	const auto instance = _instance;
+	InvokeQueued(instance, [=] {
+		if (persistentKey) {
+			instance->dcPersistentKeyChanged(dcId, persistentKey);
+		} else {
+			instance->dcTemporaryKeyChanged(dcId);
+		}
+	});
 }
 
 void Session::releaseKeyCreationOnFail() {
@@ -594,13 +576,11 @@ void Session::destroyTemporaryKey(uint64 keyId) {
 	if (!_dc->destroyTemporaryKey(keyId)) {
 		return;
 	}
-	if (sharedDc()) {
-		const auto dcId = _dc->id();
-		const auto instance = _instance;
-		InvokeQueued(instance, [=] {
-			instance->dcTemporaryKeyChanged(dcId);
-		});
-	}
+	const auto dcId = _dc->id();
+	const auto instance = _instance;
+	InvokeQueued(instance, [=] {
+		instance->dcTemporaryKeyChanged(dcId);
+	});
 }
 
 int32 Session::getDcWithShift() const {
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 2508e1cc8..dc32e130d 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -93,11 +93,6 @@ public:
 		return _options;
 	}
 
-	[[nodiscard]] const AuthKeyPtr &getKeyForCheck() const {
-		return _dcKeyForCheck;
-	}
-	void setKeyForCheck(const AuthKeyPtr &key);
-
 	not_null<QReadWriteLock*> toSendMutex() const {
 		return &_toSendLock;
 	}
@@ -190,7 +185,6 @@ private:
 	Session *_owner = nullptr;
 	mutable QMutex _ownerMutex;
 
-	AuthKeyPtr _dcKeyForCheck;
 	ConnectionOptions _options;
 
 	PreRequestMap _toSend; // map of request_id -> request, that is waiting to be sent
@@ -219,7 +213,7 @@ public:
 	Session(
 		not_null<Instance*> instance,
 		ShiftedDcId shiftedDcId,
-		Dcenter *dc);
+		not_null<Dcenter*> dc);
 	~Session();
 
 	void start();
@@ -266,8 +260,6 @@ public:
 	int32 getState() const;
 	QString transport() const;
 
-	void sendDcKeyCheck(const AuthKeyPtr &key);
-
 	void tryToReceive();
 	void needToResumeAndSend();
 	void connectionStateChange(int newState);
@@ -282,14 +274,12 @@ signals:
 	void needToRestart();
 
 private:
-	[[nodiscard]] bool sharedDc() const;
 	void watchDcKeyChanges();
 
 	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
 
 	const not_null<Instance*> _instance;
 	const ShiftedDcId _shiftedDcId = 0;
-	const std::unique_ptr<Dcenter> _ownedDc;
 	const not_null<Dcenter*> _dc;
 	const std::shared_ptr<SessionData> _data;
 

From e748a68153dbd3b4b23cb98522a0259a275265e0 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 17:25:42 +0300
Subject: [PATCH 39/91] Fix build for macOS.

---
 Telegram/ThirdParty/libtgvoip | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/ThirdParty/libtgvoip b/Telegram/ThirdParty/libtgvoip
index 75b4565a5..ade9db14f 160000
--- a/Telegram/ThirdParty/libtgvoip
+++ b/Telegram/ThirdParty/libtgvoip
@@ -1 +1 @@
-Subproject commit 75b4565a5bab8fb24afe315aeda2131c7a1f362a
+Subproject commit ade9db14ffac15cca2fec9487b59317a469e6185

From 410efc924bf8128c2a71c94dedf7e03286043fb7 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 17:23:39 +0300
Subject: [PATCH 40/91] Closed alpha version 1.9.1.2.

---
 Telegram/Resources/uwp/AppX/AppxManifest.xml | 2 +-
 Telegram/Resources/winrc/Telegram.rc         | 8 ++++----
 Telegram/Resources/winrc/Updater.rc          | 8 ++++----
 Telegram/SourceFiles/core/version.h          | 2 +-
 Telegram/SourceFiles/mtproto/connection.cpp  | 8 ++++----
 Telegram/build/version                       | 2 +-
 6 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/Telegram/Resources/uwp/AppX/AppxManifest.xml b/Telegram/Resources/uwp/AppX/AppxManifest.xml
index 3f378237a..7dd60cca9 100644
--- a/Telegram/Resources/uwp/AppX/AppxManifest.xml
+++ b/Telegram/Resources/uwp/AppX/AppxManifest.xml
@@ -9,7 +9,7 @@
   <Identity Name="TelegramMessengerLLP.TelegramDesktop"
     ProcessorArchitecture="ARCHITECTURE"
     Publisher="CN=536BC709-8EE1-4478-AF22-F0F0F26FF64A"
-    Version="1.9.1.1" />
+    Version="1.9.1.2" />
   <Properties>
     <DisplayName>Telegram Desktop</DisplayName>
     <PublisherDisplayName>Telegram FZ-LLC</PublisherDisplayName>
diff --git a/Telegram/Resources/winrc/Telegram.rc b/Telegram/Resources/winrc/Telegram.rc
index f4e3a8506..47b76bfca 100644
--- a/Telegram/Resources/winrc/Telegram.rc
+++ b/Telegram/Resources/winrc/Telegram.rc
@@ -33,8 +33,8 @@ IDI_ICON1               ICON                    "..\\art\\icon256.ico"
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,1
- PRODUCTVERSION 1,9,1,1
+ FILEVERSION 1,9,1,2
+ PRODUCTVERSION 1,9,1,2
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -51,10 +51,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop"
-            VALUE "FileVersion", "1.9.1.1"
+            VALUE "FileVersion", "1.9.1.2"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.1"
+            VALUE "ProductVersion", "1.9.1.2"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/Resources/winrc/Updater.rc b/Telegram/Resources/winrc/Updater.rc
index 74f56f7ee..2a4243e08 100644
--- a/Telegram/Resources/winrc/Updater.rc
+++ b/Telegram/Resources/winrc/Updater.rc
@@ -24,8 +24,8 @@ LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,1
- PRODUCTVERSION 1,9,1,1
+ FILEVERSION 1,9,1,2
+ PRODUCTVERSION 1,9,1,2
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -42,10 +42,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop Updater"
-            VALUE "FileVersion", "1.9.1.1"
+            VALUE "FileVersion", "1.9.1.2"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.1"
+            VALUE "ProductVersion", "1.9.1.2"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/SourceFiles/core/version.h b/Telegram/SourceFiles/core/version.h
index 84ba377de..e7ca94112 100644
--- a/Telegram/SourceFiles/core/version.h
+++ b/Telegram/SourceFiles/core/version.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001001ULL)
+#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001002ULL)
 
 #ifdef TDESKTOP_OFFICIAL_TARGET
 #define TDESKTOP_ALPHA_VERSION TDESKTOP_REQUESTED_ALPHA_VERSION
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 1aec169cd..3ea3f70a0 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -1315,7 +1315,6 @@ void ConnectionPrivate::handleReceived() {
 		}
 
 		const auto serverTime = int32(msgId >> 32);
-		const auto clientTime = base::unixtime::now();
 		const auto isReply = ((msgId & 0x03) == 1);
 		if (!isReply && ((msgId & 0x03) != 3)) {
 			LOG(("MTP Error: bad msg_id %1 in message received").arg(msgId));
@@ -1323,10 +1322,11 @@ void ConnectionPrivate::handleReceived() {
 			return restart();
 		}
 
-		bool badTime = false;
-		if (serverTime > clientTime + 60 || serverTime + 300 < clientTime) {
+		const auto clientTime = base::unixtime::now();
+		const auto badTime = (serverTime > clientTime + 60)
+			|| (serverTime + 300 < clientTime);
+		if (badTime) {
 			DEBUG_LOG(("MTP Info: bad server time from msg_id: %1, my time: %2").arg(serverTime).arg(clientTime));
-			badTime = true;
 		}
 
 		bool wasConnected = (getState() == ConnectedState);
diff --git a/Telegram/build/version b/Telegram/build/version
index c77479b5c..97b2f3729 100644
--- a/Telegram/build/version
+++ b/Telegram/build/version
@@ -3,4 +3,4 @@ AppVersionStrMajor 1.9
 AppVersionStrSmall 1.9.1
 AppVersionStr      1.9.1
 BetaChannel        0
-AlphaVersion       1009001001
+AlphaVersion       1009001002

From 54b5342af4e4a1e885b149226326edb36c33d225 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 20 Nov 2019 17:30:20 +0300
Subject: [PATCH 41/91] Closed alpha version 1.9.1.2: Key expire in 10 min.

---
 Telegram/SourceFiles/mtproto/connection.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 3ea3f70a0..7bcec5115 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -36,7 +36,7 @@ constexpr auto kMarkConnectionOldTimeout = crl::time(192000);
 constexpr auto kPingDelayDisconnect = 60;
 constexpr auto kPingSendAfter = 30 * crl::time(1000);
 constexpr auto kPingSendAfterForce = 45 * crl::time(1000);
-constexpr auto kTemporaryExpiresIn = TimeId(10);
+constexpr auto kTemporaryExpiresIn = TimeId(600);
 constexpr auto kBindKeyAdditionalExpiresTimeout = TimeId(30);
 constexpr auto kTestModeDcIdShift = 10000;
 constexpr auto kCheckSentRequestsEach = 1 * crl::time(1000);

From 276adec0ffb3d4b7571e8efaef67b4f48de76aa9 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 21 Nov 2019 13:37:39 +0300
Subject: [PATCH 42/91] Fix temporary keys for media cluster.

---
 Telegram/SourceFiles/mtproto/connection.cpp | 130 +++++++++++++-------
 Telegram/SourceFiles/mtproto/connection.h   |  16 +--
 Telegram/SourceFiles/mtproto/dc_options.cpp |  75 ++++++-----
 Telegram/SourceFiles/mtproto/dc_options.h   |  11 +-
 Telegram/SourceFiles/mtproto/dcenter.cpp    | 120 +++++++++++++-----
 Telegram/SourceFiles/mtproto/dcenter.h      |  33 +++--
 Telegram/SourceFiles/mtproto/session.cpp    |  74 ++++++-----
 Telegram/SourceFiles/mtproto/session.h      |  21 ++--
 8 files changed, 318 insertions(+), 162 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 7bcec5115..2a3072383 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/mtproto_rsa_public_key.h"
 #include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/dc_options.h"
+#include "mtproto/dcenter.h"
 #include "mtproto/connection_abstract.h"
 #include "zlib.h"
 #include "core/application.h"
@@ -78,6 +79,12 @@ using namespace details;
 	return idsStr + "]";
 }
 
+[[nodiscard]] TemporaryKeyType TemporaryKeyTypeByDcType(DcType type) {
+	return (type == DcType::MediaCluster)
+		? TemporaryKeyType::MediaCluster
+		: TemporaryKeyType::Regular;
+}
+
 void wrapInvokeAfter(SecureRequest &to, const SecureRequest &from, const RequestMap &haveSent, int32 skipBeforeRequest = 0) {
 	const auto afterId = *(mtpMsgId*)(from->after->data() + 4);
 	const auto i = afterId ? haveSent.constFind(afterId) : haveSent.cend();
@@ -164,7 +171,7 @@ void ConnectionPrivate::appendTestConnection(
 		const QString &ip,
 		int port,
 		const bytes::vector &protocolSecret) {
-	QWriteLocker lock(&stateConnMutex);
+	QWriteLocker lock(&_stateMutex);
 
 	const auto priority = (qthelp::is_ipv6(ip) ? 0 : 1)
 		+ (protocol == DcOptions::Variants::Tcp ? 1 : 0)
@@ -216,7 +223,7 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 	const auto testedDcId = cTestMode()
 		? (kTestModeDcIdShift + simpleDcId)
 		: simpleDcId;
-	return (_dcType == DcType::MediaDownload)
+	return (_currentDcType == DcType::MediaCluster)
 		? -testedDcId
 		: testedDcId;
 }
@@ -279,9 +286,11 @@ ConnectionPrivate::ConnectionPrivate(
 	ShiftedDcId shiftedDcId)
 : QObject(nullptr)
 , _instance(instance)
-, _state(DisconnectedState)
-, _shiftedDcId(shiftedDcId)
 , _owner(owner)
+, _shiftedDcId(shiftedDcId)
+, _realDcType(_instance->dcOptions()->dcType(_shiftedDcId))
+, _currentDcType(_realDcType)
+, _state(DisconnectedState)
 , _retryTimer(thread, [=] { retryByTimer(); })
 , _oldConnectionTimer(thread, [=] { markConnectionOld(); })
 , _waitForConnectedTimer(thread, [=] { waitConnectedFailed(); })
@@ -329,7 +338,7 @@ int32 ConnectionPrivate::getShiftedDcId() const {
 }
 
 int32 ConnectionPrivate::getState() const {
-	QReadLocker lock(&stateConnMutex);
+	QReadLocker lock(&_stateMutex);
 	int32 result = _state;
 	if (_state < 0) {
 		if (_retryTimer.isActive()) {
@@ -343,7 +352,7 @@ int32 ConnectionPrivate::getState() const {
 }
 
 QString ConnectionPrivate::transport() const {
-	QReadLocker lock(&stateConnMutex);
+	QReadLocker lock(&_stateMutex);
 	if (!_connection || (_state < 0)) {
 		return QString();
 	}
@@ -354,13 +363,13 @@ QString ConnectionPrivate::transport() const {
 
 bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 	if (ifState != Connection::UpdateAlways) {
-		QReadLocker lock(&stateConnMutex);
+		QReadLocker lock(&_stateMutex);
 		if (_state != ifState) {
 			return false;
 		}
 	}
 
-	QWriteLocker lock(&stateConnMutex);
+	QWriteLocker lock(&_stateMutex);
 	if (_state == state) {
 		return false;
 	}
@@ -409,6 +418,15 @@ uint32 ConnectionPrivate::nextRequestSeqNumber(bool needAck) {
 	return result * 2 + (needAck ? 1 : 0);
 }
 
+bool ConnectionPrivate::realDcTypeChanged() {
+	const auto now = _instance->dcOptions()->dcType(_shiftedDcId);
+	if (_realDcType == now) {
+		return false;
+	}
+	_realDcType = now;
+	return true;
+}
+
 bool ConnectionPrivate::markSessionAsStarted() {
 	if (_sessionMarkedAsStarted) {
 		return false;
@@ -643,10 +661,10 @@ void ConnectionPrivate::tryToSend() {
 		const auto systemLangCode = _connectionOptions->systemLangCode;
 		const auto cloudLangCode = _connectionOptions->cloudLangCode;
 		const auto langPackName = _connectionOptions->langPackName;
-		const auto deviceModel = (_dcType == DcType::Cdn)
+		const auto deviceModel = (_currentDcType == DcType::Cdn)
 			? "n/a"
 			: _instance->deviceModel();
-		const auto systemVersion = (_dcType == DcType::Cdn)
+		const auto systemVersion = (_currentDcType == DcType::Cdn)
 			? "n/a"
 			: _instance->systemVersion();
 #if defined OS_MAC_STORE
@@ -928,40 +946,38 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 		DEBUG_LOG(("MTP Error: "
 			"connectToServer() called for finished connection!"));
 		return;
+	} else if (afterConfig && (!_testConnections.empty() || _connection)) {
+		return;
+	}
+
+	destroyAllConnections();
+
+	if (realDcTypeChanged() && _keyCreator) {
+		destroyTemporaryKey();
+		return;
 	}
 
 	_connectionOptions = std::make_unique<ConnectionOptions>(
 		_sessionData->connectionOptions());
 
-	tryAcquireKeyCreation();
-
 	const auto bareDc = BareDcId(_shiftedDcId);
-	_dcType = _instance->dcOptions()->dcType(_shiftedDcId);
 
-	// Use media_only addresses only if key for this dc is already created.
-	if (_dcType == DcType::MediaDownload && _keyCreator) {
-		_dcType = DcType::Regular;
-	} else if (_dcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
+	_currentDcType = tryAcquireKeyCreation();
+	if (_currentDcType == DcType::Cdn && !_instance->isKeysDestroyer()) {
 		if (!_instance->dcOptions()->hasCDNKeysForDc(bareDc)) {
 			requestCDNConfig();
 			return;
 		}
 	}
-
-	if (afterConfig && (!_testConnections.empty() || _connection)) {
-		return;
-	}
-
-	destroyAllConnections();
 	if (_connectionOptions->proxy.type == ProxyData::Type::Mtproto) {
 		// host, port, secret for mtproto proxy are taken from proxy.
 		appendTestConnection(DcOptions::Variants::Tcp, {}, 0, {});
 	} else {
 		using Variants = DcOptions::Variants;
-		const auto special = (_dcType == DcType::Temporary);
+		const auto special = (_currentDcType == DcType::Temporary);
 		const auto variants = _instance->dcOptions()->lookup(
 			bareDc,
-			_dcType,
+			_currentDcType,
 			_connectionOptions->proxy.type != ProxyData::Type::None);
 		const auto useIPv4 = special ? true : _connectionOptions->useIPv4;
 		const auto useIPv6 = special ? false : _connectionOptions->useIPv6;
@@ -1351,7 +1367,11 @@ void ConnectionPrivate::handleReceived() {
 		auto from = decryptedInts + kEncryptedHeaderIntsCount;
 		auto end = from + (messageLength / kIntSize);
 		auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
-		MTP_LOG(_shiftedDcId, ("Recv: ") + details::DumpToText(sfrom, end) + QString(" (keyId:%1)").arg(_encryptionKey->keyId()));
+		MTP_LOG(_shiftedDcId, ("Recv: ")
+			+ details::DumpToText(sfrom, end)
+			+ QString(" (protocolDcId:%1,key:%2)"
+			).arg(getProtocolDcId()
+			).arg(_encryptionKey->keyId()));
 
 		if (_receivedMessageIds.registerMsgId(msgId, needAck)) {
 			res = handleOneReceived(from, end, msgId, serverTime, serverSalt, badTime);
@@ -1860,9 +1880,11 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 				response);
 			switch (result) {
 			case DcKeyBindState::Success:
-				_sessionData->releaseKeyCreationOnDone(
+				if (!_sessionData->releaseKeyCreationOnDone(
 					_encryptionKey,
-					base::take(_keyCreator)->bindPersistentKey());
+					base::take(_keyCreator)->bindPersistentKey())) {
+					return HandleResult::DestroyTemporaryKey;
+				}
 				_sessionData->queueNeedToResumeAndSend();
 				return HandleResult::Success;
 			case DcKeyBindState::DefinitelyDestroyed:
@@ -1967,7 +1989,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		return HandleResult::ResetSession;
 	}
 
-	if (_dcType == DcType::Regular) {
+	if (_currentDcType == DcType::Regular) {
 		mtpBuffer update(end - from);
 		if (end > from) memcpy(update.data(), from, (end - from) * sizeof(mtpPrime));
 
@@ -1986,7 +2008,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			LOG(("Message Error: unknown constructor 0x%1").arg(cons, 0, 16));
 		}
 	} else {
-		LOG(("Message Error: unexpected updates in dcType: %1").arg(static_cast<int>(_dcType)));
+		LOG(("Message Error: unexpected updates in dcType: %1"
+			).arg(static_cast<int>(_currentDcType)));
 	}
 
 	return HandleResult::Success;
@@ -2311,17 +2334,27 @@ void ConnectionPrivate::checkAuthKey() {
 	} else if (_instance->isKeysDestroyer()) {
 		applyAuthKey(_sessionData->getPersistentKey());
 	} else {
-		applyAuthKey(_sessionData->getTemporaryKey());
+		applyAuthKey(_sessionData->getTemporaryKey(
+			TemporaryKeyTypeByDcType(_currentDcType)));
 	}
 }
 
 void ConnectionPrivate::updateAuthKey() {
-	if (_instance->isKeysDestroyer() || _keyCreator) {
+	if (_instance->isKeysDestroyer() || _keyCreator || !_connection) {
 		return;
 	}
 
-	DEBUG_LOG(("AuthKey Info: Connection updating key from Session, dc %1").arg(_shiftedDcId));
-	applyAuthKey(_sessionData->getTemporaryKey());
+	DEBUG_LOG(("AuthKey Info: Connection updating key from Session, dc %1"
+		).arg(_shiftedDcId));
+	const auto myKeyType = TemporaryKeyTypeByDcType(_currentDcType);
+	applyAuthKey(_sessionData->getTemporaryKey(myKeyType));
+
+	if (_connection
+		&& !_encryptionKey
+		&& myKeyType == TemporaryKeyType::MediaCluster
+		&& _sessionData->getTemporaryKey(TemporaryKeyType::Regular)) {
+		restart();
+	}
 }
 
 void ConnectionPrivate::setCurrentKeyId(uint64 newKeyId) {
@@ -2395,11 +2428,17 @@ bool ConnectionPrivate::destroyOldEnoughPersistentKey() {
 	return true;
 }
 
-void ConnectionPrivate::tryAcquireKeyCreation() {
-	if (_instance->isKeysDestroyer()
-		|| _keyCreator
-		|| !_sessionData->acquireKeyCreation()) {
-		return;
+DcType ConnectionPrivate::tryAcquireKeyCreation() {
+	if (_keyCreator) {
+		return _currentDcType;
+	} else if (_instance->isKeysDestroyer()) {
+		return _realDcType;
+	}
+
+	const auto keyType = TemporaryKeyTypeByDcType(_realDcType);
+	const auto acquired = _sessionData->acquireKeyCreation(keyType);
+	if (acquired == CreatingKeyType::None) {
+		return _realDcType;
 	}
 
 	using Result = DcKeyResult;
@@ -2409,7 +2448,7 @@ void ConnectionPrivate::tryAcquireKeyCreation() {
 		if (!result) {
 			releaseKeyCreationOnFail();
 			if (result.error() == Error::UnknownPublicKey) {
-				if (_dcType == DcType::Cdn) {
+				if (_realDcType == DcType::Cdn) {
 					LOG(("Warning: CDN public RSA key not found"));
 					requestCDNConfig();
 					return;
@@ -2457,11 +2496,14 @@ void ConnectionPrivate::tryAcquireKeyCreation() {
 	};
 
 	auto request = DcKeyRequest();
-	request.persistentNeeded = !_sessionData->getPersistentKey();
+	request.persistentNeeded = (acquired == CreatingKeyType::Persistent);
 	request.temporaryExpiresIn = kTemporaryExpiresIn;
 	_keyCreator = std::make_unique<BoundKeyCreator>(
 		request,
 		std::move(delegate));
+	const auto forceUseRegular = (_realDcType == DcType::MediaCluster)
+		&& (acquired != CreatingKeyType::TemporaryMediaCluster);
+	return forceUseRegular ? DcType::Regular : _realDcType;
 }
 
 void ConnectionPrivate::authKeyChecked() {
@@ -2548,7 +2590,11 @@ bool ConnectionPrivate::sendSecureRequest(
 	memcpy(request->data() + 2, &_sessionId, 2 * sizeof(mtpPrime));
 
 	auto from = request->constData() + 4;
-	MTP_LOG(_shiftedDcId, ("Send: ") + details::DumpToText(from, from + messageSize) + QString(" (keyId:%1)").arg(_encryptionKey->keyId()));
+	MTP_LOG(_shiftedDcId, ("Send: ")
+		+ details::DumpToText(from, from + messageSize)
+		+ QString(" (protocolDcId:%1,key:%2)"
+		).arg(getProtocolDcId()
+		).arg(_encryptionKey->keyId()));
 
 #ifdef TDESKTOP_MTPROTO_OLD
 	uint32 padding = fullSize - 4 - messageSize;
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index fa8ec88cd..b53a827ad 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -181,7 +181,7 @@ private:
 		crl::time msCanWait = 0,
 		bool forceContainer = false);
 
-	void tryAcquireKeyCreation();
+	[[nodiscard]] DcType tryAcquireKeyCreation();
 	void resetSession();
 	void checkAuthKey();
 	void authKeyChecked();
@@ -193,20 +193,22 @@ private:
 
 	void setCurrentKeyId(uint64 newKeyId);
 	void changeSessionId();
-	void setSessionSalt(uint64 salt);
 	[[nodiscard]] bool markSessionAsStarted();
 	[[nodiscard]] uint32 nextRequestSeqNumber(bool needAck);
 
-	const not_null<Instance*> _instance;
-	DcType _dcType = DcType::Regular;
+	[[nodiscard]] bool realDcTypeChanged();
 
-	mutable QReadWriteLock stateConnMutex;
+	const not_null<Instance*> _instance;
+	const not_null<Connection*> _owner;
+	const ShiftedDcId _shiftedDcId = 0;
+	DcType _realDcType = DcType();
+	DcType _currentDcType = DcType();
+
+	mutable QReadWriteLock _stateMutex;
 	int32 _state = DisconnectedState;
 
 	bool _needSessionReset = false;
 
-	ShiftedDcId _shiftedDcId = 0;
-	not_null<Connection*> _owner;
 	ConnectionPointer _connection;
 	std::vector<TestConnection> _testConnections;
 	crl::time _startedConnectingAt = 0;
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index a072048d4..7e22e4c5b 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -540,8 +540,9 @@ DcType DcOptions::dcType(ShiftedDcId shiftedDcId) const {
 	if (_cdnDcIds.find(BareDcId(shiftedDcId)) != _cdnDcIds.cend()) {
 		return DcType::Cdn;
 	}
-	if (isDownloadDcId(shiftedDcId)) {
-		return DcType::MediaDownload;
+	const auto dcId = BareDcId(shiftedDcId);
+	if (isDownloadDcId(shiftedDcId) && hasMediaOnlyOptionsFor(dcId)) {
+		return DcType::MediaCluster;
 	}
 	return DcType::Regular;
 }
@@ -599,40 +600,54 @@ auto DcOptions::lookup(
 		bool throughProxy) const -> Variants {
 	using Flag = Flag;
 	auto result = Variants();
-	{
-		ReadLocker lock(this);
-		const auto i = _data.find(dcId);
-		if (i == end(_data)) {
-			return result;
+
+	ReadLocker lock(this);
+	const auto i = _data.find(dcId);
+	if (i == end(_data)) {
+		return result;
+	}
+	for (const auto &endpoint : i->second) {
+		const auto flags = endpoint.flags;
+		if (type == DcType::Cdn && !(flags & Flag::f_cdn)) {
+			continue;
+		} else if (type != DcType::MediaCluster
+			&& (flags & Flag::f_media_only)) {
+			continue;
+		} else if (!ValidateSecret(endpoint.secret)) {
+			continue;
 		}
-		for (const auto &endpoint : i->second) {
-			const auto flags = endpoint.flags;
-			if (type == DcType::Cdn && !(flags & Flag::f_cdn)) {
-				continue;
-			} else if (type != DcType::MediaDownload
-				&& (flags & Flag::f_media_only)) {
-				continue;
-			} else if (!ValidateSecret(endpoint.secret)) {
-				continue;
-			}
-			const auto address = (flags & Flag::f_ipv6)
-				? Variants::IPv6
-				: Variants::IPv4;
-			result.data[address][Variants::Tcp].push_back(endpoint);
-			if (!(flags & (Flag::f_tcpo_only | Flag::f_secret))) {
-				result.data[address][Variants::Http].push_back(endpoint);
-			}
-		}
-		if (type == DcType::MediaDownload) {
-			FilterIfHasWithFlag(result, Flag::f_media_only);
-		}
-		if (throughProxy) {
-			FilterIfHasWithFlag(result, Flag::f_static);
+		const auto address = (flags & Flag::f_ipv6)
+			? Variants::IPv6
+			: Variants::IPv4;
+		result.data[address][Variants::Tcp].push_back(endpoint);
+		if (!(flags & (Flag::f_tcpo_only | Flag::f_secret))) {
+			result.data[address][Variants::Http].push_back(endpoint);
 		}
 	}
+	if (type == DcType::MediaCluster) {
+		FilterIfHasWithFlag(result, Flag::f_media_only);
+	}
+	if (throughProxy) {
+		FilterIfHasWithFlag(result, Flag::f_static);
+	}
 	return result;
 }
 
+bool DcOptions::hasMediaOnlyOptionsFor(DcId dcId) const {
+	ReadLocker lock(this);
+	const auto i = _data.find(dcId);
+	if (i == end(_data)) {
+		return false;
+	}
+	for (const auto &endpoint : i->second) {
+		const auto flags = endpoint.flags;
+		if (flags & Flag::f_media_only) {
+			return true;
+		}
+	}
+	return false;
+}
+
 void DcOptions::FilterIfHasWithFlag(Variants &variants, Flag flag) {
 	const auto is = [&](const Endpoint &endpoint) {
 		return (endpoint.flags & flag) != 0;
diff --git a/Telegram/SourceFiles/mtproto/dc_options.h b/Telegram/SourceFiles/mtproto/dc_options.h
index 1e910f9a6..70b7a79dd 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.h
+++ b/Telegram/SourceFiles/mtproto/dc_options.h
@@ -22,7 +22,7 @@ namespace MTP {
 enum class DcType {
 	Regular,
 	Temporary,
-	MediaDownload,
+	MediaCluster,
 	Cdn,
 };
 class DcOptions {
@@ -89,8 +89,11 @@ public:
 		};
 		std::vector<Endpoint> data[AddressTypeCount][ProtocolCount];
 	};
-	Variants lookup(DcId dcId, DcType type, bool throughProxy) const;
-	DcType dcType(ShiftedDcId shiftedDcId) const;
+	[[nodiscard]] Variants lookup(
+		DcId dcId,
+		DcType type,
+		bool throughProxy) const;
+	[[nodiscard]] DcType dcType(ShiftedDcId shiftedDcId) const;
 
 	void setCDNConfig(const MTPDcdnConfig &config);
 	[[nodiscard]] bool hasCDNKeysForDc(DcId dcId) const;
@@ -121,6 +124,8 @@ private:
 		const std::map<DcId, std::vector<Endpoint>> &b);
 	static void FilterIfHasWithFlag(Variants &variants, Flag flag);
 
+	[[nodiscard]] bool hasMediaOnlyOptionsFor(DcId dcId) const;
+
 	void processFromList(const QVector<MTPDcOption> &options, bool overwrite);
 	void computeCdnDcIds();
 
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/dcenter.cpp
index 22e212698..663d72897 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/dcenter.cpp
@@ -21,6 +21,32 @@ namespace {
 constexpr auto kEnumerateDcTimeout = 8000; // 8 seconds timeout for help_getConfig to work (then move to other dc)
 constexpr auto kSpecialRequestTimeoutMs = 6000; // 4 seconds timeout for it to work in a specially requested dc.
 
+int IndexByType(TemporaryKeyType type) {
+	switch (type) {
+	case TemporaryKeyType::Regular: return 0;
+	case TemporaryKeyType::MediaCluster: return 1;
+	}
+	Unexpected("Type value in IndexByType.");
+}
+
+int IndexByType(CreatingKeyType type) {
+	switch (type) {
+	case CreatingKeyType::Persistent:
+	case CreatingKeyType::TemporaryRegular: return 0;
+	case CreatingKeyType::TemporaryMediaCluster: return 1;
+	}
+	Unexpected("Creating type value in IndexByType.");
+}
+
+const char *NameOfType(CreatingKeyType type) {
+	switch (type) {
+	case CreatingKeyType::Persistent: return "persistent";
+	case CreatingKeyType::TemporaryRegular: return "regular";
+	case CreatingKeyType::TemporaryMediaCluster: return "media";
+	}
+	Unexpected("Type value in NameOfType.");
+}
+
 } // namespace
 
 Dcenter::Dcenter(DcId dcId, AuthKeyPtr &&key)
@@ -32,9 +58,9 @@ DcId Dcenter::id() const {
 	return _id;
 }
 
-AuthKeyPtr Dcenter::getTemporaryKey() const {
+AuthKeyPtr Dcenter::getTemporaryKey(TemporaryKeyType type) const {
 	QReadLocker lock(&_mutex);
-	return _temporaryKey;
+	return _temporaryKeys[IndexByType(type)];
 }
 
 AuthKeyPtr Dcenter::getPersistentKey() const {
@@ -44,12 +70,14 @@ AuthKeyPtr Dcenter::getPersistentKey() const {
 
 bool Dcenter::destroyTemporaryKey(uint64 keyId) {
 	QWriteLocker lock(&_mutex);
-	if (!_temporaryKey || _temporaryKey->keyId() != keyId) {
-		return false;
+	for (auto &key : _temporaryKeys) {
+		if (key && key->keyId() == keyId) {
+			key = nullptr;
+			_connectionInited = false;
+			return true;
+		}
 	}
-	_temporaryKey = nullptr;
-	_connectionInited = false;
-	return true;
+	return false;
 }
 
 bool Dcenter::destroyConfirmedForgottenKey(uint64 keyId) {
@@ -57,7 +85,9 @@ bool Dcenter::destroyConfirmedForgottenKey(uint64 keyId) {
 	if (!_persistentKey || _persistentKey->keyId() != keyId) {
 		return false;
 	}
-	_temporaryKey = nullptr;
+	for (auto &key : _temporaryKeys) {
+		key = nullptr;
+	}
 	_persistentKey = nullptr;
 	_connectionInited = false;
 	return true;
@@ -73,40 +103,66 @@ void Dcenter::setConnectionInited(bool connectionInited) {
 	_connectionInited = connectionInited;
 }
 
-bool Dcenter::acquireKeyCreation() {
+CreatingKeyType Dcenter::acquireKeyCreation(TemporaryKeyType type) {
 	QReadLocker lock(&_mutex);
-	if (_temporaryKey != nullptr) {
-		return false;
+	if (type == TemporaryKeyType::MediaCluster) {
+		int a = 0;
+	}
+	const auto index = IndexByType(type);
+	auto &key = _temporaryKeys[index];
+	if (key != nullptr) {
+		return CreatingKeyType::None;
 	}
 	auto expected = false;
-	return _creatingKey.compare_exchange_strong(expected, true);
+	const auto regular = IndexByType(TemporaryKeyType::Regular);
+	if (type == TemporaryKeyType::MediaCluster && _temporaryKeys[regular]) {
+		return !_creatingKeys[index].compare_exchange_strong(expected, true)
+			? CreatingKeyType::None
+			: CreatingKeyType::TemporaryMediaCluster;
+	}
+	return !_creatingKeys[regular].compare_exchange_strong(expected, true)
+		? CreatingKeyType::None
+		: !_persistentKey
+		? CreatingKeyType::Persistent
+		: CreatingKeyType::TemporaryRegular;
 }
 
-void Dcenter::releaseKeyCreationOnFail() {
-	Expects(_creatingKey);
-	Expects(_temporaryKey == nullptr);
-
-	_creatingKey = false;
-}
-
-void Dcenter::releaseKeyCreationOnDone(
+bool Dcenter::releaseKeyCreationOnDone(
+		CreatingKeyType type,
 		const AuthKeyPtr &temporaryKey,
-		const AuthKeyPtr &persistentKey) {
-	Expects(_creatingKey);
-	Expects(_temporaryKey == nullptr);
+		const AuthKeyPtr &persistentKeyUsedForBind) {
+	Expects(_creatingKeys[IndexByType(type)]);
+	Expects(_temporaryKeys[IndexByType(type)] == nullptr);
+	Expects(temporaryKey != nullptr);
 
 	QWriteLocker lock(&_mutex);
-	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1, %2), "
-		"emitting authKeyChanged, dc %3"
-		).arg(temporaryKey ? temporaryKey->keyId() : 0
-		).arg(persistentKey ? persistentKey->keyId() : 0
-		).arg(_id));
-	_temporaryKey = temporaryKey;
-	if (persistentKey) {
-		_persistentKey = persistentKey;
+	if (type != CreatingKeyType::Persistent
+		&& _persistentKey != persistentKeyUsedForBind) {
+		return false;
 	}
+	if (type == CreatingKeyType::Persistent) {
+		_persistentKey = persistentKeyUsedForBind;
+	} else if (_persistentKey != persistentKeyUsedForBind) {
+		return false;
+	}
+	_temporaryKeys[IndexByType(type)] = temporaryKey;
+	_creatingKeys[IndexByType(type)] = false;
 	_connectionInited = false;
-	_creatingKey = false;
+
+	DEBUG_LOG(("AuthKey Info: Dcenter::releaseKeyCreationOnDone(%1, %2, %3)."
+		).arg(NameOfType(type)
+		).arg(temporaryKey ? temporaryKey->keyId() : 0
+		).arg(persistentKeyUsedForBind
+			? persistentKeyUsedForBind->keyId()
+			: 0));
+	return true;
+}
+
+void Dcenter::releaseKeyCreationOnFail(CreatingKeyType type) {
+	Expects(_creatingKeys[IndexByType(type)]);
+	Expects(_temporaryKeys[IndexByType(type)] == nullptr);
+
+	_creatingKeys[IndexByType(type)] = false;
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/dcenter.h
index 96326c425..0b4636014 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/dcenter.h
@@ -15,6 +15,18 @@ using AuthKeyPtr = std::shared_ptr<AuthKey>;
 
 namespace internal {
 
+enum class TemporaryKeyType {
+	Regular,
+	MediaCluster
+};
+
+enum class CreatingKeyType {
+	None,
+	Persistent,
+	TemporaryRegular,
+	TemporaryMediaCluster
+};
+
 class Dcenter : public QObject {
 public:
 	// Main thread.
@@ -22,29 +34,30 @@ public:
 
 	// Thread-safe.
 	[[nodiscard]] DcId id() const;
-
-	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
+	[[nodiscard]] AuthKeyPtr getTemporaryKey(TemporaryKeyType type) const;
+	[[nodiscard]] CreatingKeyType acquireKeyCreation(TemporaryKeyType type);
+	bool releaseKeyCreationOnDone(
+		CreatingKeyType type,
+		const AuthKeyPtr &temporaryKey,
+		const AuthKeyPtr &persistentKeyUsedForBind);
+	void releaseKeyCreationOnFail(CreatingKeyType type);
 	bool destroyTemporaryKey(uint64 keyId);
 	bool destroyConfirmedForgottenKey(uint64 keyId);
-	void releaseKeyCreationOnDone(
-		const AuthKeyPtr &temporaryKey,
-		const AuthKeyPtr &persistentKey);
 
 	[[nodiscard]] bool connectionInited() const;
 	void setConnectionInited(bool connectionInited = true);
 
-	[[nodiscard]] bool acquireKeyCreation();
-	void releaseKeyCreationOnFail();
-
 private:
+	static constexpr auto kTemporaryKeysCount = 2;
+
 	const DcId _id = 0;
 	mutable QReadWriteLock _mutex;
 
-	AuthKeyPtr _temporaryKey;
+	AuthKeyPtr _temporaryKeys[kTemporaryKeysCount];
 	AuthKeyPtr _persistentKey;
 	bool _connectionInited = false;
-	std::atomic<bool> _creatingKey = false;
+	std::atomic<bool> _creatingKeys[kTemporaryKeysCount] = { false };
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 5fb0b9e66..2dc955cb6 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -164,9 +164,9 @@ bool SessionData::connectionInited() const {
 	return _owner ? _owner->connectionInited() : false;
 }
 
-AuthKeyPtr SessionData::getTemporaryKey() const {
+AuthKeyPtr SessionData::getTemporaryKey(TemporaryKeyType type) const {
 	QMutexLocker lock(&_ownerMutex);
-	return _owner ? _owner->getTemporaryKey() : nullptr;
+	return _owner ? _owner->getTemporaryKey(type) : nullptr;
 }
 
 AuthKeyPtr SessionData::getPersistentKey() const {
@@ -174,18 +174,20 @@ AuthKeyPtr SessionData::getPersistentKey() const {
 	return _owner ? _owner->getPersistentKey() : nullptr;
 }
 
-bool SessionData::acquireKeyCreation() {
+CreatingKeyType SessionData::acquireKeyCreation(TemporaryKeyType type) {
 	QMutexLocker lock(&_ownerMutex);
-	return _owner ? _owner->acquireKeyCreation() : false;
+	return _owner ? _owner->acquireKeyCreation(type) : CreatingKeyType::None;
 }
 
-void SessionData::releaseKeyCreationOnDone(
+bool SessionData::releaseKeyCreationOnDone(
 		const AuthKeyPtr &temporaryKey,
-		const AuthKeyPtr &persistentKey) {
+		const AuthKeyPtr &persistentKeyUsedForBind) {
 	QMutexLocker lock(&_ownerMutex);
-	if (_owner) {
-		_owner->releaseKeyCreationOnDone(temporaryKey, persistentKey);
-	}
+	return _owner
+		? _owner->releaseKeyCreationOnDone(
+			temporaryKey,
+			persistentKeyUsedForBind)
+		: false;
 }
 
 void SessionData::releaseKeyCreationOnFail() {
@@ -529,42 +531,56 @@ void Session::sendPrepared(
 	}
 }
 
-bool Session::acquireKeyCreation() {
-	Expects(!_myKeyCreation);
+CreatingKeyType Session::acquireKeyCreation(TemporaryKeyType type) {
+	Expects(_myKeyCreation == CreatingKeyType::None);
 
-	if (!_dc->acquireKeyCreation()) {
-		return false;
-	}
-	_myKeyCreation = true;
-	return true;
+	_myKeyCreation = _dc->acquireKeyCreation(type);
+	return _myKeyCreation;
 }
 
-void Session::releaseKeyCreationOnDone(
+bool Session::releaseKeyCreationOnDone(
 		const AuthKeyPtr &temporaryKey,
-		const AuthKeyPtr &persistentKey) {
-	Expects(_myKeyCreation);
+		const AuthKeyPtr &persistentKeyUsedForBind) {
+	Expects(_myKeyCreation != CreatingKeyType::None);
+	Expects(persistentKeyUsedForBind != nullptr);
+
+	const auto wasKeyCreation = std::exchange(
+		_myKeyCreation,
+		CreatingKeyType::None);
+	const auto result = _dc->releaseKeyCreationOnDone(
+		wasKeyCreation,
+		temporaryKey,
+		persistentKeyUsedForBind);
+
+	if (!result) {
+		DEBUG_LOG(("AuthKey Info: Persistent key changed "
+			"while binding temporary, dcWithShift %1"
+			).arg(_shiftedDcId));
+		return false;
+	}
 
 	DEBUG_LOG(("AuthKey Info: Session key bound, setting, dcWithShift %1"
 		).arg(_shiftedDcId));
-	_dc->releaseKeyCreationOnDone(temporaryKey, persistentKey);
-	_myKeyCreation = false;
 
 	const auto dcId = _dc->id();
 	const auto instance = _instance;
 	InvokeQueued(instance, [=] {
-		if (persistentKey) {
-			instance->dcPersistentKeyChanged(dcId, persistentKey);
+		if (wasKeyCreation == CreatingKeyType::Persistent) {
+			instance->dcPersistentKeyChanged(dcId, persistentKeyUsedForBind);
 		} else {
 			instance->dcTemporaryKeyChanged(dcId);
 		}
 	});
+	return true;
 }
 
 void Session::releaseKeyCreationOnFail() {
-	Expects(_myKeyCreation);
+	Expects(_myKeyCreation != CreatingKeyType::None);
 
-	_dc->releaseKeyCreationOnFail();
-	_myKeyCreation = false;
+	const auto wasKeyCreation = std::exchange(
+		_myKeyCreation,
+		CreatingKeyType::None);
+	_dc->releaseKeyCreationOnFail(wasKeyCreation);
 }
 
 void Session::notifyDcConnectionInited() {
@@ -587,8 +603,8 @@ int32 Session::getDcWithShift() const {
 	return _shiftedDcId;
 }
 
-AuthKeyPtr Session::getTemporaryKey() const {
-	return _dc->getTemporaryKey();
+AuthKeyPtr Session::getTemporaryKey(TemporaryKeyType type) const {
+	return _dc->getTemporaryKey(type);
 }
 
 AuthKeyPtr Session::getPersistentKey() const {
@@ -643,7 +659,7 @@ void Session::tryToReceive() {
 }
 
 Session::~Session() {
-	if (_myKeyCreation) {
+	if (_myKeyCreation != CreatingKeyType::None) {
 		releaseKeyCreationOnFail();
 	}
 	Assert(_connection == nullptr);
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index dc32e130d..d7dd23b3d 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -24,6 +24,9 @@ namespace internal {
 class Dcenter;
 class Connection;
 
+enum class TemporaryKeyType;
+enum class CreatingKeyType;
+
 using PreRequestMap = QMap<mtpRequestId, SecureRequest>;
 using RequestMap = QMap<mtpMsgId, SecureRequest>;
 
@@ -163,11 +166,11 @@ public:
 
 	[[nodiscard]] bool connectionInited() const;
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
-	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
-	[[nodiscard]] bool acquireKeyCreation();
-	void releaseKeyCreationOnDone(
+	[[nodiscard]] AuthKeyPtr getTemporaryKey(TemporaryKeyType type) const;
+	[[nodiscard]] CreatingKeyType acquireKeyCreation(TemporaryKeyType type);
+	[[nodiscard]] bool releaseKeyCreationOnDone(
 		const AuthKeyPtr &temporaryKey,
-		const AuthKeyPtr &persistentKey);
+		const AuthKeyPtr &persistentKeyUsedForBind);
 	void releaseKeyCreationOnFail();
 	void destroyTemporaryKey(uint64 keyId);
 	void resend(
@@ -229,7 +232,7 @@ public:
 	// Thread-safe.
 	[[nodiscard]] ShiftedDcId getDcWithShift() const;
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
-	[[nodiscard]] AuthKeyPtr getTemporaryKey() const;
+	[[nodiscard]] AuthKeyPtr getTemporaryKey(TemporaryKeyType type) const;
 	[[nodiscard]] bool connectionInited() const;
 	void resend(
 		mtpMsgId msgId,
@@ -245,10 +248,10 @@ public:
 		bool newRequest = true);
 
 	// Connection thread.
-	[[nodiscard]] bool acquireKeyCreation();
-	void releaseKeyCreationOnDone(
+	[[nodiscard]] CreatingKeyType acquireKeyCreation(TemporaryKeyType type);
+	[[nodiscard]] bool releaseKeyCreationOnDone(
 		const AuthKeyPtr &temporaryKey,
-		const AuthKeyPtr &persistentKey);
+		const AuthKeyPtr &persistentKeyUsedForBind);
 	void releaseKeyCreationOnFail();
 	void destroyTemporaryKey(uint64 keyId);
 
@@ -289,7 +292,7 @@ private:
 	bool _needToReceive = false;
 
 	AuthKeyPtr _dcKeyForCheck;
-	bool _myKeyCreation = false;
+	CreatingKeyType _myKeyCreation = CreatingKeyType();
 
 	crl::time _msSendCall = 0;
 	crl::time _msWait = 0;

From 311a1274c574d720a0dca03768968fa025ed7cf2 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 21 Nov 2019 13:46:29 +0300
Subject: [PATCH 43/91] Closed alpha version 1.9.1.2: Update lib_spellcheck.

---
 Telegram/lib_spellcheck | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/lib_spellcheck b/Telegram/lib_spellcheck
index 6dcaae361..b815a8385 160000
--- a/Telegram/lib_spellcheck
+++ b/Telegram/lib_spellcheck
@@ -1 +1 @@
-Subproject commit 6dcaae361d942defb5908400bb3f4bf805a5e740
+Subproject commit b815a83854939cac6aa37430be54193b2b0e50c6

From ec84589ecae3949ec4aa95ed83a1cb0255d01ce4 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 21 Nov 2019 18:18:53 +0300
Subject: [PATCH 44/91] Update lib_lottie with useCache fixes.

---
 Telegram/lib_lottie | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/lib_lottie b/Telegram/lib_lottie
index 94efb93b0..6debd5de4 160000
--- a/Telegram/lib_lottie
+++ b/Telegram/lib_lottie
@@ -1 +1 @@
-Subproject commit 94efb93b07ca46a3f0142cf75059093f8dfe6f06
+Subproject commit 6debd5de46160a06f1f29ee23f903424c716ee07

From 2597bc9f4e024f5472d84bac96aa52d504704797 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 21 Nov 2019 18:28:49 +0300
Subject: [PATCH 45/91] Fix layout of polls with huge questions.

---
 Telegram/SourceFiles/history/view/media/history_view_poll.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/history/view/media/history_view_poll.cpp b/Telegram/SourceFiles/history/view/media/history_view_poll.cpp
index d095ad661..afabb10c7 100644
--- a/Telegram/SourceFiles/history/view/media/history_view_poll.cpp
+++ b/Telegram/SourceFiles/history/view/media/history_view_poll.cpp
@@ -302,10 +302,12 @@ void Poll::updateTexts() {
 	const auto willStartAnimation = checkAnimationStart();
 
 	if (_question.toString() != _poll->question) {
+		auto options = Ui::WebpageTextTitleOptions();
+		options.maxw = options.maxh = 0;
 		_question.setText(
 			st::historyPollQuestionStyle,
 			_poll->question,
-			Ui::WebpageTextTitleOptions());
+			options);
 	}
 	if (_closed != _poll->closed || _subtitle.isEmpty()) {
 		_closed = _poll->closed;

From 46a42e02bc729897767b273cf1d2aa2a1d1eae6b Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 22 Nov 2019 12:06:48 +0300
Subject: [PATCH 46/91] Fix lost bind key messages.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 454 +++++++++---------
 Telegram/SourceFiles/mtproto/connection.h     |  12 +-
 .../details/mtproto_bound_key_creator.cpp     |  11 +-
 .../details/mtproto_bound_key_creator.h       |   3 +-
 .../mtproto/details/mtproto_dc_key_binder.cpp |  20 +-
 .../mtproto/details/mtproto_dc_key_binder.h   |   7 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 121 +----
 Telegram/SourceFiles/mtproto/session.h        |  58 +--
 8 files changed, 255 insertions(+), 431 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 2a3072383..e5d5be76a 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -443,13 +443,10 @@ mtpMsgId ConnectionPrivate::prepareToSend(
 
 	if (const auto msgId = request.getMsgId()) {
 		// resending this request
-		QWriteLocker lock(_sessionData->toResendMutex());
-		auto &toResend = _sessionData->toResendMap();
-		const auto i = toResend.find(msgId);
-		if (i != toResend.cend()) {
-			toResend.erase(i);
+		const auto i = _resendingIds.find(msgId);
+		if (i != _resendingIds.cend()) {
+			_resendingIds.erase(i);
 		}
-		lock.unlock();
 
 		return (forceNewMsgId || msgId > currentLastId)
 			? replaceMsgId(request, currentLastId)
@@ -470,33 +467,29 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 	if (oldMsgId == newId) {
 		return newId;
 	}
-	QWriteLocker locker(_sessionData->toResendMutex());
-	// haveSentMutex() and wereAckedMutex() were locked in tryToSend()
-
-	auto &toResend = _sessionData->toResendMap();
-	auto &wereAcked = _sessionData->wereAckedMap();
+	// haveSentMutex() was locked in tryToSend()
 	auto &haveSent = _sessionData->haveSentMap();
 
-	while (toResend.constFind(newId) != toResend.cend()
-		|| wereAcked.constFind(newId) != wereAcked.cend()
+	while (_resendingIds.contains(newId)
+		|| _ackedIds.contains(newId)
 		|| haveSent.constFind(newId) != haveSent.cend()) {
 		newId = base::unixtime::mtproto_msg_id();
 	}
 
 	MTP_LOG(_shiftedDcId, ("[r%1] msg_id %2 -> %3").arg(request->requestId).arg(oldMsgId).arg(newId));
 
-	const auto i = toResend.find(oldMsgId);
-	if (i != toResend.cend()) {
-		const auto req = i.value();
-		toResend.erase(i);
-		toResend.insert(newId, req);
+	const auto i = _resendingIds.find(oldMsgId);
+	if (i != _resendingIds.end()) {
+		const auto requestId = i->second;
+		_resendingIds.erase(i);
+		_resendingIds.emplace(newId, requestId);
 	}
 
-	const auto j = wereAcked.find(oldMsgId);
-	if (j != wereAcked.cend()) {
-		const auto req = j.value();
-		wereAcked.erase(j);
-		wereAcked.insert(newId, req);
+	const auto j = _ackedIds.find(oldMsgId);
+	if (j != _ackedIds.cend()) {
+		const auto requestId = j->second;
+		_ackedIds.erase(j);
+		_ackedIds.emplace(newId, requestId);
 	}
 
 	const auto k = haveSent.find(oldMsgId);
@@ -618,14 +611,14 @@ void ConnectionPrivate::tryToSend() {
 			}
 			stateRequest = SecureRequest::Serialize(MTPMsgsStateReq(
 				MTP_msgs_state_req(MTP_vector<MTPlong>(ids))));
-			// Add to haveSent / wereAcked maps, but don't add to requestMap.
+			// Add to haveSent / _ackedIds, but don't add to requestMap.
 			stateRequest->requestId = GetNextRequestId();
 		}
 		if (_connection->usingHttpWait()) {
 			httpWaitRequest = SecureRequest::Serialize(MTPHttpWait(
 				MTP_http_wait(MTP_int(100), MTP_int(30), MTP_int(25000))));
 		}
-		if (_keyCreator && _keyCreator->bindReadyToRequest()) {
+		if (!_bindMsgId && _keyCreator && _keyCreator->readyToBind()) {
 			bindDcKeyRequest = _keyCreator->prepareBindRequest(
 				_encryptionKey,
 				_sessionId);
@@ -635,22 +628,6 @@ void ConnectionPrivate::tryToSend() {
 			// seqNo for it manually here.
 			bindDcKeyRequest.setSeqNo(
 				nextRequestSeqNumber(bindDcKeyRequest.needAck()));
-		//} else if (!_keyChecker) {
-		//	if (const auto &keyForCheck = _sessionData->getKeyForCheck()) {
-		//		_keyChecker = std::make_unique<details::DcKeyChecker>(
-		//			_instance,
-		//			_shiftedDcId,
-		//			keyForCheck);
-		//		bindDcKeyRequest = _keyChecker->prepareRequest(
-		//			_encryptionKey,
-		//			_sessionId);
-
-		//		// This is a special request with msgId used inside the message
-		//		// body, so it is prepared already with a msgId and we place
-		//		// seqNo for it manually here.
-		//		bindDcKeyRequest.setSeqNo(
-		//			nextRequestSeqNumber(bindDcKeyRequest.needAck()));
-		//	}
 		}
 	}
 
@@ -750,8 +727,11 @@ void ConnectionPrivate::tryToSend() {
 			const auto msgId = prepareToSend(
 				toSendRequest,
 				base::unixtime::mtproto_msg_id(),
-				forceNewMsgId);
-			if (pingRequest) {
+				forceNewMsgId && !bindDcKeyRequest);
+			if (bindDcKeyRequest) {
+				_bindMsgId = msgId;
+				needAnyResponse = true;
+			} else if (pingRequest) {
 				_pingMsgId = msgId;
 				needAnyResponse = true;
 			} else if (resendRequest || stateRequest) {
@@ -792,8 +772,7 @@ void ConnectionPrivate::tryToSend() {
 
 					needAnyResponse = true;
 				} else {
-					QWriteLocker locker3(_sessionData->wereAckedMutex());
-					_sessionData->wereAckedMap().insert(msgId, toSendRequest->requestId);
+					_ackedIds.emplace(msgId, toSendRequest->requestId);
 				}
 			}
 		} else { // send in container
@@ -833,10 +812,6 @@ void ConnectionPrivate::tryToSend() {
 			QWriteLocker locker2(_sessionData->haveSentMutex());
 			auto &haveSent = _sessionData->haveSentMap();
 
-			// the fact of this lock is used in replaceMsgId()
-			QWriteLocker locker3(_sessionData->wereAckedMutex());
-			auto &wereAcked = _sessionData->wereAckedMap();
-
 			// prepare "request-like" wrap for msgId vector
 			auto haveSentIdsWrap = SecureRequest::Prepare(idsWrapSize);
 			haveSentIdsWrap->msDate = 0; // Container: msDate = 0, seqNo = 0.
@@ -844,6 +819,15 @@ void ConnectionPrivate::tryToSend() {
 			haveSentIdsWrap->resize(haveSentIdsWrap->size() + idsWrapSize);
 			auto haveSentArr = (mtpMsgId*)(haveSentIdsWrap->data() + 8);
 
+			if (bindDcKeyRequest) {
+				_bindMsgId = placeToContainer(
+					toSendRequest,
+					bigMsgId,
+					false,
+					haveSentArr,
+					bindDcKeyRequest);
+				needAnyResponse = true;
+			}
 			if (pingRequest) {
 				_pingMsgId = placeToContainer(
 					toSendRequest,
@@ -852,7 +836,8 @@ void ConnectionPrivate::tryToSend() {
 					haveSentArr,
 					pingRequest);
 				needAnyResponse = true;
-			} else if (resendRequest || stateRequest || bindDcKeyRequest) {
+			}
+			if (resendRequest || stateRequest) {
 				needAnyResponse = true;
 			}
 			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
@@ -890,7 +875,7 @@ void ConnectionPrivate::tryToSend() {
 
 						needAnyResponse = true;
 					} else {
-						wereAcked.insert(msgId, req->requestId);
+						_ackedIds.emplace(msgId, req->requestId);
 					}
 				}
 				if (!added) {
@@ -908,7 +893,6 @@ void ConnectionPrivate::tryToSend() {
 			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, resendRequest);
 			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, ackRequest);
 			if (httpWaitRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, httpWaitRequest);
-			if (bindDcKeyRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, bindDcKeyRequest);
 
 			const auto containerMsgId = prepareToSend(
 				toSendRequest,
@@ -1044,6 +1028,7 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 
 	setState(ConnectingState);
 
+	_bindMsgId = 0;
 	_pingId = _pingMsgId = _pingIdToSend = _pingSendAt = 0;
 	_pingSender.cancel();
 
@@ -1352,7 +1337,7 @@ void ConnectionPrivate::handleReceived() {
 				_sessionSalt = serverSalt;
 
 				if (setState(ConnectedState, ConnectingState)) {
-					_sessionData->resendAll();
+					resendAll();
 				}
 			} else {
 				DEBUG_LOG(("MTP Info: other salt received... received: %1, my salt: %2").arg(serverSalt).arg(_sessionSalt));
@@ -1416,10 +1401,16 @@ void ConnectionPrivate::handleReceived() {
 	}
 }
 
-ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPrime *from, const mtpPrime *end, uint64 msgId, int32 serverTime, uint64 serverSalt, bool badTime) {
-	const auto cons = mtpTypeId(*from);
+ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
+		const mtpPrime *from,
+		const mtpPrime *end,
+		uint64 msgId,
+		int32 serverTime,
+		uint64 serverSalt,
+		bool badTime) {
+	Expects(from < end);
 
-	switch (cons) {
+	switch (mtpTypeId(*from)) {
 
 	case mtpc_gzip_packed: {
 		DEBUG_LOG(("Message Info: gzip container"));
@@ -1495,18 +1486,15 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		if (!msg.read(from, end)) {
 			return HandleResult::ParseError;
 		}
-		auto &ids = msg.c_msgs_ack().vmsg_ids().v;
-		uint32 idsCount = ids.size();
+		const auto &ids = msg.c_msgs_ack().vmsg_ids().v;
+		DEBUG_LOG(("Message Info: acks received, ids: %1"
+			).arg(LogIdsVector(ids)));
+		if (ids.isEmpty()) {
+			return badTime ? HandleResult::Ignored : HandleResult::Success;
+		}
 
-		DEBUG_LOG(("Message Info: acks received, ids: %1").arg(LogIdsVector(ids)));
-		if (!idsCount) return (badTime ? HandleResult::Ignored : HandleResult::Success);
-
-		if (badTime) {
-			if (requestsFixTimeSalt(ids, serverTime, serverSalt)) {
-				badTime = false;
-			} else {
-				return HandleResult::Ignored;
-			}
+		if (badTime && !requestsFixTimeSalt(ids, serverTime, serverSalt)) {
+			return HandleResult::Ignored;
 		}
 		requestsAcked(ids);
 	} return HandleResult::Success;
@@ -1519,11 +1507,8 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		const auto &data(msg.c_bad_msg_notification());
 		LOG(("Message Info: bad message notification received (error_code %3) for msg_id = %1, seq_no = %2").arg(data.vbad_msg_id().v).arg(data.vbad_msg_seqno().v).arg(data.verror_code().v));
 
-		mtpMsgId resendId = data.vbad_msg_id().v;
-		if (resendId == _pingMsgId) {
-			_pingId = 0;
-		}
-		int32 errorCode = data.verror_code().v;
+		const auto resendId = data.vbad_msg_id().v;
+		const auto errorCode = data.verror_code().v;
 		if (false
 			|| errorCode == 16
 			|| errorCode == 17
@@ -1619,13 +1604,11 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		if (!msg.read(from, end)) {
 			return HandleResult::ParseError;
 		}
-		const auto &data(msg.c_bad_server_salt());
+		const auto &data = msg.c_bad_server_salt();
 		DEBUG_LOG(("Message Info: bad server salt received (error_code %4) for msg_id = %1, seq_no = %2, new salt: %3").arg(data.vbad_msg_id().v).arg(data.vbad_msg_seqno().v).arg(data.vnew_server_salt().v).arg(data.verror_code().v));
 
-		mtpMsgId resendId = data.vbad_msg_id().v;
-		if (resendId == _pingMsgId) {
-			_pingId = 0;
-		} else if (!wasSent(resendId)) {
+		const auto resendId = data.vbad_msg_id().v;
+		if (!wasSent(resendId)) {
 			DEBUG_LOG(("Message Error: such message was not sent recently %1").arg(resendId));
 			return (badTime ? HandleResult::Ignored : HandleResult::Success);
 		}
@@ -1634,7 +1617,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		base::unixtime::update(serverTime);
 
 		if (setState(ConnectedState, ConnectingState)) {
-			_sessionData->resendAll();
+			resendAll();
 		}
 
 		badTime = false;
@@ -1661,11 +1644,6 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		{
 			const auto minRecv = _receivedMessageIds.min();
 			const auto maxRecv = _receivedMessageIds.max();
-
-			QReadLocker locker(_sessionData->wereAckedMutex());
-			const auto &wereAcked = _sessionData->wereAckedMap();
-			const auto wereAckedEnd = wereAcked.cend();
-
 			for (uint32 i = 0, l = idsCount; i < l; ++i) {
 				char state = 0;
 				uint64 reqMsgId = ids[i].v;
@@ -1679,7 +1657,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 						state |= 0x02;
 					} else {
 						state |= 0x04;
-						if (wereAcked.constFind(reqMsgId) != wereAckedEnd) {
+						if (_ackedIds.contains(reqMsgId)) {
 							state |= 0x80; // we know, that server knows, that we received request
 						}
 						if (msgIdState == ReceivedIdsManager::State::NeedsAck) { // need ack, so we sent ack
@@ -1837,20 +1815,21 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		if (!reqMsgId.read(++from, end)) {
 			return HandleResult::ParseError;
 		}
-		mtpTypeId typeId = from[0];
+		const auto requestMsgId = reqMsgId.v;
 
-		DEBUG_LOG(("RPC Info: response received for %1, queueing...").arg(reqMsgId.v));
+		DEBUG_LOG(("RPC Info: response received for %1, queueing...").arg(requestMsgId));
 
 		QVector<MTPlong> ids(1, reqMsgId);
 		if (badTime) {
 			if (requestsFixTimeSalt(ids, serverTime, serverSalt)) {
 				badTime = false;
 			} else {
-				DEBUG_LOG(("Message Info: error, such message was not sent recently %1").arg(reqMsgId.v));
+				DEBUG_LOG(("Message Info: error, such message was not sent recently %1").arg(requestMsgId));
 				return HandleResult::Ignored;
 			}
 		}
 
+		mtpTypeId typeId = from[0];
 		if (typeId == mtpc_gzip_packed) {
 			DEBUG_LOG(("RPC Info: gzip container"));
 			response = ungzip(++from, end);
@@ -1874,36 +1853,17 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 		}
 		requestsAcked(ids, true);
 
-		if (_keyCreator) {
-			const auto result = _keyCreator->handleBindResponse(
-				reqMsgId,
-				response);
-			switch (result) {
-			case DcKeyBindState::Success:
-				if (!_sessionData->releaseKeyCreationOnDone(
-					_encryptionKey,
-					base::take(_keyCreator)->bindPersistentKey())) {
-					return HandleResult::DestroyTemporaryKey;
-				}
-				_sessionData->queueNeedToResumeAndSend();
-				return HandleResult::Success;
-			case DcKeyBindState::DefinitelyDestroyed:
-				if (destroyOldEnoughPersistentKey()) {
-					return HandleResult::DestroyTemporaryKey;
-				}
-				[[fallthrough]];
-			case DcKeyBindState::Failed:
-				_sessionData->queueNeedToResumeAndSend();
-				return HandleResult::Success;
-			}
+		const auto bindResult = handleBindResponse(requestMsgId, response);
+		if (bindResult != HandleResult::Ignored) {
+			return bindResult;
 		}
-		auto requestId = wasSent(reqMsgId.v);
+		const auto requestId = wasSent(requestMsgId);
 		if (requestId && requestId != mtpRequestId(0xFFFFFFFF)) {
 			// Save rpc_result for processing in the main thread.
 			QWriteLocker locker(_sessionData->haveReceivedMutex());
 			_sessionData->haveReceivedResponses().insert(requestId, response);
 		} else {
-			DEBUG_LOG(("RPC Info: requestId not found for msgId %1").arg(reqMsgId.v));
+			DEBUG_LOG(("RPC Info: requestId not found for msgId %1").arg(requestMsgId));
 		}
 	} return HandleResult::Success;
 
@@ -1942,7 +1902,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 			}
 		}
 		for (const auto msgId : toResend) {
-			_sessionData->resend(msgId, 10, true);
+			resend(msgId, 10, true);
 		}
 
 		mtpBuffer update(from - start);
@@ -1991,22 +1951,13 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 
 	if (_currentDcType == DcType::Regular) {
 		mtpBuffer update(end - from);
-		if (end > from) memcpy(update.data(), from, (end - from) * sizeof(mtpPrime));
+		if (end > from) {
+			memcpy(update.data(), from, (end - from) * sizeof(mtpPrime));
+		}
 
 		// Notify main process about the new updates.
 		QWriteLocker locker(_sessionData->haveReceivedMutex());
 		_sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
-
-		if (cons != mtpc_updatesTooLong
-			&& cons != mtpc_updateShortMessage
-			&& cons != mtpc_updateShortChatMessage
-			&& cons != mtpc_updateShortSentMessage
-			&& cons != mtpc_updateShort
-			&& cons != mtpc_updatesCombined
-			&& cons != mtpc_updates) {
-			// Maybe some new unknown update?
-			LOG(("Message Error: unknown constructor 0x%1").arg(cons, 0, 16));
-		}
 	} else {
 		LOG(("Message Error: unexpected updates in dcType: %1"
 			).arg(static_cast<int>(_currentDcType)));
@@ -2015,6 +1966,34 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(const mtpPr
 	return HandleResult::Success;
 }
 
+ConnectionPrivate::HandleResult ConnectionPrivate::handleBindResponse(
+		mtpMsgId requestMsgId,
+		const mtpBuffer &response) {
+	if (!_keyCreator || !_bindMsgId || _bindMsgId != requestMsgId) {
+		return HandleResult::Ignored;
+	}
+	const auto result = _keyCreator->handleBindResponse(response);
+	switch (result) {
+	case DcKeyBindState::Success:
+		if (!_sessionData->releaseKeyCreationOnDone(
+			_encryptionKey,
+			base::take(_keyCreator)->bindPersistentKey())) {
+			return HandleResult::DestroyTemporaryKey;
+		}
+		_sessionData->queueNeedToResumeAndSend();
+		return HandleResult::Success;
+	case DcKeyBindState::DefinitelyDestroyed:
+		if (destroyOldEnoughPersistentKey()) {
+			return HandleResult::DestroyTemporaryKey;
+		}
+		[[fallthrough]];
+	case DcKeyBindState::Failed:
+		_sessionData->queueNeedToResumeAndSend();
+		return HandleResult::Success;
+	}
+	Unexpected("Result of BoundKeyCreator::handleBindResponse.");
+}
+
 mtpBuffer ConnectionPrivate::ungzip(const mtpPrime *from, const mtpPrime *end) const {
 	mtpBuffer result; // * 4 because of mtpPrime type
 	result.resize(0);
@@ -2090,87 +2069,80 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 	auto clearedBecauseTooOld = std::vector<RPCCallbackClear>();
 	QVector<MTPlong> toAckMore;
 	{
-		QWriteLocker locker1(_sessionData->wereAckedMutex());
-		auto &wereAcked = _sessionData->wereAckedMap();
+		QWriteLocker locker2(_sessionData->haveSentMutex());
+		auto &haveSent = _sessionData->haveSentMap();
 
-		{
-			QWriteLocker locker2(_sessionData->haveSentMutex());
-			auto &haveSent = _sessionData->haveSentMap();
-
-			for (uint32 i = 0; i < idsCount; ++i) {
-				mtpMsgId msgId = ids[i].v;
-				const auto req = haveSent.find(msgId);
-				if (req != haveSent.cend()) {
-					if (!req.value()->msDate) {
-						DEBUG_LOG(("Message Info: container ack received, msgId %1").arg(ids[i].v));
-						uint32 inContCount = ((*req)->size() - 8) / 2;
-						const mtpMsgId *inContId = (const mtpMsgId *)(req.value()->constData() + 8);
-						toAckMore.reserve(toAckMore.size() + inContCount);
-						for (uint32 j = 0; j < inContCount; ++j) {
-							toAckMore.push_back(MTP_long(*(inContId++)));
-						}
+		for (uint32 i = 0; i < idsCount; ++i) {
+			mtpMsgId msgId = ids[i].v;
+			const auto req = haveSent.find(msgId);
+			if (req != haveSent.cend()) {
+				if (!req.value()->msDate) {
+					DEBUG_LOG(("Message Info: container ack received, msgId %1").arg(ids[i].v));
+					uint32 inContCount = ((*req)->size() - 8) / 2;
+					const mtpMsgId *inContId = (const mtpMsgId *)(req.value()->constData() + 8);
+					toAckMore.reserve(toAckMore.size() + inContCount);
+					for (uint32 j = 0; j < inContCount; ++j) {
+						toAckMore.push_back(MTP_long(*(inContId++)));
+					}
+					haveSent.erase(req);
+				} else {
+					mtpRequestId reqId = req.value()->requestId;
+					bool moveToAcked = byResponse;
+					if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
+						moveToAcked = !_instance->hasCallbacks(reqId);
+					}
+					if (moveToAcked) {
+						_ackedIds.emplace(msgId, reqId);
 						haveSent.erase(req);
 					} else {
-						mtpRequestId reqId = req.value()->requestId;
-						bool moveToAcked = byResponse;
-						if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
-							moveToAcked = !_instance->hasCallbacks(reqId);
-						}
-						if (moveToAcked) {
-							wereAcked.insert(msgId, reqId);
-							haveSent.erase(req);
+						DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(reqId));
+					}
+				}
+			} else {
+				DEBUG_LOG(("Message Info: msgId %1 was not found in recent sent, while acking requests, searching in resend...").arg(msgId));
+				const auto reqIt = _resendingIds.find(msgId);
+				if (reqIt != _resendingIds.end()) {
+					const auto reqId = reqIt->second;
+					bool moveToAcked = byResponse;
+					if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
+						moveToAcked = !_instance->hasCallbacks(reqId);
+					}
+					if (moveToAcked) {
+						QWriteLocker locker4(_sessionData->toSendMutex());
+						auto &toSend = _sessionData->toSendMap();
+						const auto req = toSend.find(reqId);
+						if (req != toSend.cend()) {
+							_ackedIds.emplace(msgId, req.value()->requestId);
+							if (req.value()->requestId != reqId) {
+								DEBUG_LOG(("Message Error: for msgId %1 found resent request, requestId %2, contains requestId %3").arg(msgId).arg(reqId).arg(req.value()->requestId));
+							} else {
+								DEBUG_LOG(("Message Info: acked msgId %1 that was prepared to resend, requestId %2").arg(msgId).arg(reqId));
+							}
+							toSend.erase(req);
 						} else {
-							DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(reqId));
+							DEBUG_LOG(("Message Info: msgId %1 was found in recent resent, requestId %2 was not found in prepared to send").arg(msgId));
 						}
+						_resendingIds.erase(reqIt);
+					} else {
+						DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(reqId));
 					}
 				} else {
-					DEBUG_LOG(("Message Info: msgId %1 was not found in recent sent, while acking requests, searching in resend...").arg(msgId));
-					QWriteLocker locker3(_sessionData->toResendMutex());
-					auto &toResend = _sessionData->toResendMap();
-					const auto reqIt = toResend.find(msgId);
-					if (reqIt != toResend.cend()) {
-						const auto reqId = reqIt.value();
-						bool moveToAcked = byResponse;
-						if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
-							moveToAcked = !_instance->hasCallbacks(reqId);
-						}
-						if (moveToAcked) {
-							QWriteLocker locker4(_sessionData->toSendMutex());
-							auto &toSend = _sessionData->toSendMap();
-							const auto req = toSend.find(reqId);
-							if (req != toSend.cend()) {
-								wereAcked.insert(msgId, req.value()->requestId);
-								if (req.value()->requestId != reqId) {
-									DEBUG_LOG(("Message Error: for msgId %1 found resent request, requestId %2, contains requestId %3").arg(msgId).arg(reqId).arg(req.value()->requestId));
-								} else {
-									DEBUG_LOG(("Message Info: acked msgId %1 that was prepared to resend, requestId %2").arg(msgId).arg(reqId));
-								}
-								toSend.erase(req);
-							} else {
-								DEBUG_LOG(("Message Info: msgId %1 was found in recent resent, requestId %2 was not found in prepared to send").arg(msgId));
-							}
-							toResend.erase(reqIt);
-						} else {
-							DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(reqId));
-						}
-					} else {
-						DEBUG_LOG(("Message Info: msgId %1 was not found in recent resent either").arg(msgId));
-					}
+					DEBUG_LOG(("Message Info: msgId %1 was not found in recent resent either").arg(msgId));
 				}
 			}
 		}
+	}
 
-		uint32 ackedCount = wereAcked.size();
-		if (ackedCount > kIdsBufferSize) {
-			DEBUG_LOG(("Message Info: removing some old acked sent msgIds %1").arg(ackedCount - kIdsBufferSize));
-			clearedBecauseTooOld.reserve(ackedCount - kIdsBufferSize);
-			while (ackedCount-- > kIdsBufferSize) {
-				auto i = wereAcked.begin();
-				clearedBecauseTooOld.push_back(RPCCallbackClear(
-					i.value(),
-					RPCError::TimeoutError));
-				wereAcked.erase(i);
-			}
+	auto ackedCount = _ackedIds.size();
+	if (ackedCount > kIdsBufferSize) {
+		DEBUG_LOG(("Message Info: removing some old acked sent msgIds %1").arg(ackedCount - kIdsBufferSize));
+		clearedBecauseTooOld.reserve(ackedCount - kIdsBufferSize);
+		while (ackedCount-- > kIdsBufferSize) {
+			auto i = _ackedIds.begin();
+			clearedBecauseTooOld.push_back(RPCCallbackClear(
+				i->second,
+				RPCError::TimeoutError));
+			_ackedIds.erase(i);
 		}
 	}
 
@@ -2204,10 +2176,8 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 			const auto haveSentEnd = haveSent.cend();
 			if (haveSent.find(requestMsgId) == haveSentEnd) {
 				DEBUG_LOG(("Message Info: state was received for msgId %1, but request is not found, looking in resent requests...").arg(requestMsgId));
-				QWriteLocker locker2(_sessionData->toResendMutex());
-				auto &toResend = _sessionData->toResendMap();
-				const auto reqIt = toResend.find(requestMsgId);
-				if (reqIt != toResend.cend()) {
+				const auto reqIt = _resendingIds.find(requestMsgId);
+				if (reqIt != _resendingIds.cend()) {
 					if ((state & 0x07) != 0x04) { // was received
 						DEBUG_LOG(("Message Info: state was received for msgId %1, state %2, already resending in container").arg(requestMsgId).arg((int32)state));
 					} else {
@@ -2230,22 +2200,70 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 	}
 }
 
+void ConnectionPrivate::clearSpecialMsgId(mtpMsgId msgId) {
+	if (msgId == _pingMsgId) {
+		_pingMsgId = 0;
+		_pingId = 0;
+	} else if (msgId == _bindMsgId) {
+		_bindMsgId = 0;
+	}
+}
+
 void ConnectionPrivate::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
 		bool forceContainer) {
-	if (msgId != _pingMsgId) {
-		_sessionData->resend(msgId, msCanWait, forceContainer);
+	const auto guard = gsl::finally([&] {
+		clearSpecialMsgId(msgId);
+		if (msCanWait >= 0) {
+			_sessionData->queueSendAnything(msCanWait);
+		}
+	});
+
+	auto lock = QWriteLocker(_sessionData->haveSentMutex());
+	auto &haveSent = _sessionData->haveSentMap();
+	auto i = haveSent.find(msgId);
+	if (i == haveSent.end()) {
+		return;
+	}
+	auto request = i.value();
+	haveSent.erase(i);
+	lock.unlock();
+
+	// For container just resend all messages we can.
+	if (request.isSentContainer()) {
+		DEBUG_LOG(("Message Info: resending container from haveSent, msgId %1").arg(msgId));
+		const mtpMsgId *ids = (const mtpMsgId *)(request->constData() + 8);
+		for (uint32 i = 0, l = (request->size() - 8) >> 1; i < l; ++i) {
+			resend(ids[i], -1, true);
+		}
+	} else if (!request.isStateRequest()) {
+		request->msDate = forceContainer ? 0 : crl::now();
+		_resendingIds.emplace(msgId, request->requestId);
+		{
+			QWriteLocker locker(_sessionData->toSendMutex());
+			_sessionData->toSendMap().insert(request->requestId, request);
+		}
 	}
 }
 
-void ConnectionPrivate::resendMany(
-		QVector<mtpMsgId> msgIds,
-		crl::time msCanWait,
-		bool forceContainer) {
-	for (const auto msgId : msgIds) {
-		resend(msgId, msCanWait, forceContainer);
+void ConnectionPrivate::resendAll() {
+	auto toResend = std::vector<mtpMsgId>();
+
+	auto lock = QReadLocker(_sessionData->haveSentMutex());
+	const auto &haveSent = _sessionData->haveSentMap();
+	toResend.reserve(haveSent.size());
+	for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
+		if (!i.value().isSentContainer()) {
+			toResend.push_back(i.key());
+		}
 	}
+	lock.unlock();
+
+	for (const auto msgId : toResend) {
+		resend(msgId, -1, true);
+	}
+	_sessionData->queueSendAnything();
 }
 
 void ConnectionPrivate::onConnected(
@@ -2470,10 +2488,6 @@ DcType ConnectionPrivate::tryAcquireKeyCreation() {
 			).arg(result->persistentServerSalt));
 
 		_sessionSalt = result->temporaryServerSalt;
-		if (result->persistentKey) {
-			_sessionData->clearForNewKey(_instance);
-		}
-
 		auto key = result->persistentKey
 			? std::move(result->persistentKey)
 			: _sessionData->getPersistentKey();
@@ -2512,7 +2526,7 @@ void ConnectionPrivate::authKeyChecked() {
 	});
 
 	if (_sessionSalt && setState(ConnectedState)) {
-		_sessionData->resendAll();
+		resendAll();
 	} // else receive salt in bad_server_salt first, then try to send all the requests
 
 	_pingIdToSend = rand_value<uint64>(); // get server_salt
@@ -2651,7 +2665,9 @@ bool ConnectionPrivate::sendSecureRequest(
 }
 
 mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
-	if (msgId == _pingMsgId) return mtpRequestId(0xFFFFFFFF);
+	if (msgId == _pingMsgId || msgId == _bindMsgId) {
+		return mtpRequestId(0xFFFFFFFF);
+	}
 	{
 		QReadLocker locker(_sessionData->haveSentMutex());
 		const auto &haveSent = _sessionData->haveSentMap();
@@ -2662,17 +2678,11 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 				: mtpRequestId(0xFFFFFFFF);
 		}
 	}
-	{
-		QReadLocker locker(_sessionData->toResendMutex());
-		const auto &toResend = _sessionData->toResendMap();
-		const auto i = toResend.constFind(msgId);
-		if (i != toResend.cend()) return i.value();
+	if (const auto i = _resendingIds.find(msgId); i != end(_resendingIds)) {
+		return i->second;
 	}
-	{
-		QReadLocker locker(_sessionData->wereAckedMutex());
-		const auto &wereAcked = _sessionData->wereAckedMap();
-		const auto i = wereAcked.constFind(msgId);
-		if (i != wereAcked.cend()) return i.value();
+	if (const auto i = _ackedIds.find(msgId); i != end(_ackedIds)) {
+		return i->second;
 	}
 	return 0;
 }
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index b53a827ad..36c5706d3 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -154,6 +154,9 @@ private:
 	mtpRequestId wasSent(mtpMsgId msgId) const;
 
 	[[nodiscard]] HandleResult handleOneReceived(const mtpPrime *from, const mtpPrime *end, uint64 msgId, int32 serverTime, uint64 serverSalt, bool badTime);
+	[[nodiscard]] HandleResult handleBindResponse(
+		mtpMsgId requestMsgId,
+		const mtpBuffer &response);
 	mtpBuffer ungzip(const mtpPrime *from, const mtpPrime *end) const;
 	void handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked);
 
@@ -176,10 +179,8 @@ private:
 		mtpMsgId msgId,
 		crl::time msCanWait = 0,
 		bool forceContainer = false);
-	void resendMany(
-		QVector<mtpMsgId> msgIds,
-		crl::time msCanWait = 0,
-		bool forceContainer = false);
+	void resendAll();
+	void clearSpecialMsgId(mtpMsgId msgId);
 
 	[[nodiscard]] DcType tryAcquireKeyCreation();
 	void resetSession();
@@ -249,8 +250,11 @@ private:
 	QVector<MTPlong> _resendRequestData;
 	base::flat_set<mtpMsgId> _stateRequestData;
 	details::ReceivedIdsManager _receivedMessageIds;
+	base::flat_map<mtpMsgId, mtpRequestId> _resendingIds;
+	base::flat_map<mtpMsgId, mtpRequestId> _ackedIds;
 
 	std::unique_ptr<details::BoundKeyCreator> _keyCreator;
+	mtpMsgId _bindMsgId = 0;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
index ab8dd2488..ae68422b5 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
@@ -50,8 +50,8 @@ void BoundKeyCreator::restartBinder() {
 	}
 }
 
-bool BoundKeyCreator::bindReadyToRequest() const {
-	return _binder ? !_binder->requested() : false;
+bool BoundKeyCreator::readyToBind() const {
+	return _binder.has_value();
 }
 
 SecureRequest BoundKeyCreator::prepareBindRequest(
@@ -63,11 +63,10 @@ SecureRequest BoundKeyCreator::prepareBindRequest(
 }
 
 DcKeyBindState BoundKeyCreator::handleBindResponse(
-		MTPlong requestMsgId,
 		const mtpBuffer &response) {
-	return _binder
-		? _binder->handleResponse(requestMsgId, response)
-		: DcKeyBindState::Unknown;
+	Expects(_binder.has_value());
+
+	return _binder->handleResponse(response);
 }
 
 AuthKeyPtr BoundKeyCreator::bindPersistentKey() const {
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
index 78d624b96..e8a7bf100 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
@@ -31,12 +31,11 @@ public:
 
 	void bind(AuthKeyPtr &&persistentKey);
 	void restartBinder();
-	[[nodiscard]] bool bindReadyToRequest() const;
+	[[nodiscard]] bool readyToBind() const;
 	[[nodiscard]] SecureRequest prepareBindRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId);
 	[[nodiscard]] DcKeyBindState handleBindResponse(
-		MTPlong requestMsgId,
 		const mtpBuffer &response);
 	[[nodiscard]] AuthKeyPtr bindPersistentKey() const;
 
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
index 44ca8a4c7..736a6f4fa 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
@@ -77,46 +77,34 @@ DcKeyBinder::DcKeyBinder(AuthKeyPtr &&persistentKey)
 	Expects(_persistentKey != nullptr);
 }
 
-bool DcKeyBinder::requested() const {
-	return _requestMsgId != 0;
-}
-
 SecureRequest DcKeyBinder::prepareRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId) {
-	Expects(_requestMsgId == 0);
 	Expects(temporaryKey != nullptr);
 	Expects(temporaryKey->expiresAt() != 0);
 
 	const auto nonce = openssl::RandomValue<uint64>();
-	_requestMsgId = base::unixtime::mtproto_msg_id();
+	const auto msgId = base::unixtime::mtproto_msg_id();
 	auto result = SecureRequest::Serialize(MTPauth_BindTempAuthKey(
 		MTP_long(_persistentKey->keyId()),
 		MTP_long(nonce),
 		MTP_int(temporaryKey->expiresAt()),
 		MTP_bytes(EncryptBindAuthKeyInner(
 			_persistentKey,
-			_requestMsgId,
+			msgId,
 			MTP_bind_auth_key_inner(
 				MTP_long(nonce),
 				MTP_long(temporaryKey->keyId()),
 				MTP_long(_persistentKey->keyId()),
 				MTP_long(sessionId),
 				MTP_int(temporaryKey->expiresAt()))))));
-	result.setMsgId(_requestMsgId);
+	result.setMsgId(msgId);
 	return result;
 }
 
-DcKeyBindState DcKeyBinder::handleResponse(
-		MTPlong requestMsgId,
-		const mtpBuffer &response) {
+DcKeyBindState DcKeyBinder::handleResponse(const mtpBuffer &response) {
 	Expects(!response.isEmpty());
 
-	if (!_requestMsgId || requestMsgId.v != _requestMsgId) {
-		return DcKeyBindState::Unknown;
-	}
-	_requestMsgId = 0;
-
 	auto from = response.begin();
 	const auto end = from + response.size();
 	auto error = MTPRpcError();
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
index db311b3b4..ba18176e4 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
@@ -17,7 +17,6 @@ class Instance;
 namespace MTP::details {
 
 enum class DcKeyBindState {
-	Unknown,
 	Success,
 	Failed,
 	DefinitelyDestroyed,
@@ -27,18 +26,14 @@ class DcKeyBinder final {
 public:
 	explicit DcKeyBinder(AuthKeyPtr &&persistentKey);
 
-	[[nodiscard]] bool requested() const;
 	[[nodiscard]] SecureRequest prepareRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId);
-	[[nodiscard]] DcKeyBindState handleResponse(
-		MTPlong requestMsgId,
-		const mtpBuffer &response);
+	[[nodiscard]] DcKeyBindState handleResponse(const mtpBuffer &response);
 	[[nodiscard]] AuthKeyPtr persistentKey() const;
 
 private:
 	AuthKeyPtr _persistentKey;
-	mtpMsgId _requestMsgId = 0;
 
 };
 
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 2dc955cb6..ba2ce7fd4 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -64,48 +64,6 @@ void SessionData::notifyConnectionInited(const ConnectionOptions &options) {
 	}
 }
 
-void SessionData::clearForNewKey(not_null<Instance*> instance) {
-	auto clearCallbacks = std::vector<RPCCallbackClear>();
-	{
-		QReadLocker locker1(haveSentMutex());
-		QReadLocker locker2(toResendMutex());
-		QReadLocker locker3(haveReceivedMutex());
-		QReadLocker locker4(wereAckedMutex());
-		clearCallbacks.reserve(_haveSent.size() + _toResend.size() + _wereAcked.size());
-		for (auto i = _haveSent.cbegin(), e = _haveSent.cend(); i != e; ++i) {
-			auto requestId = i.value()->requestId;
-			if (!_receivedResponses.contains(requestId)) {
-				clearCallbacks.push_back(requestId);
-			}
-		}
-		for (auto i = _toResend.cbegin(), e = _toResend.cend(); i != e; ++i) {
-			auto requestId = i.value();
-			if (!_receivedResponses.contains(requestId)) {
-				clearCallbacks.push_back(requestId);
-			}
-		}
-		for (auto i = _wereAcked.cbegin(), e = _wereAcked.cend(); i != e; ++i) {
-			auto requestId = i.value();
-			if (!_receivedResponses.contains(requestId)) {
-				clearCallbacks.push_back(requestId);
-			}
-		}
-	}
-	{
-		QWriteLocker locker(haveSentMutex());
-		_haveSent.clear();
-	}
-	{
-		QWriteLocker locker(toResendMutex());
-		_toResend.clear();
-	}
-	{
-		QWriteLocker locker(wereAckedMutex());
-		_wereAcked.clear();
-	}
-	instance->clearCallbacksDelayed(std::move(clearCallbacks));
-}
-
 void SessionData::queueTryToReceive() {
 	withSession([](not_null<Session*> session) {
 		session->tryToReceive();
@@ -142,23 +100,6 @@ void SessionData::queueSendMsgsStateInfo(quint64 msgId, QByteArray data) {
 	});
 }
 
-void SessionData::resend(
-		mtpMsgId msgId,
-		crl::time msCanWait,
-		bool forceContainer) {
-	QMutexLocker lock(&_ownerMutex);
-	if (_owner) {
-		_owner->resend(msgId, msCanWait, forceContainer);
-	}
-}
-
-void SessionData::resendAll() {
-	QMutexLocker lock(&_ownerMutex);
-	if (_owner) {
-		_owner->resendAll();
-	}
-}
-
 bool SessionData::connectionInited() const {
 	QMutexLocker lock(&_ownerMutex);
 	return _owner ? _owner->connectionInited() : false;
@@ -455,72 +396,16 @@ QString Session::transport() const {
 	return _connection ? _connection->transport() : QString();
 }
 
-void Session::resend(
-		mtpMsgId msgId,
-		crl::time msCanWait,
-		bool forceContainer) {
-	auto lock = QWriteLocker(_data->haveSentMutex());
-	auto &haveSent = _data->haveSentMap();
-
-	auto i = haveSent.find(msgId);
-	if (i == haveSent.end()) {
-		return;
-	}
-	auto request = i.value();
-	haveSent.erase(i);
-	lock.unlock();
-
-	// For container just resend all messages we can.
-	if (request.isSentContainer()) {
-		DEBUG_LOG(("Message Info: resending container from haveSent, msgId %1").arg(msgId));
-		const mtpMsgId *ids = (const mtpMsgId *)(request->constData() + 8);
-		for (uint32 i = 0, l = (request->size() - 8) >> 1; i < l; ++i) {
-			resend(ids[i], 10, true);
-		}
-	} else if (!request.isStateRequest()) {
-		request->msDate = forceContainer ? 0 : crl::now();
-		{
-			QWriteLocker locker(_data->toResendMutex());
-			_data->toResendMap().insert(msgId, request->requestId);
-		}
-		sendPrepared(request, msCanWait, false);
-	}
-}
-
-void Session::resendAll() {
-	QVector<mtpMsgId> toResend;
-	{
-		QReadLocker locker(_data->haveSentMutex());
-		const auto &haveSent = _data->haveSentMap();
-		toResend.reserve(haveSent.size());
-		for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
-			if (i.value()->requestId) {
-				toResend.push_back(i.key());
-			}
-		}
-	}
-	for (uint32 i = 0, l = toResend.size(); i < l; ++i) {
-		resend(toResend[i], -1, true);
-	}
-	InvokeQueued(this, [=] {
-		sendAnything();
-	});
-}
-
 void Session::sendPrepared(
 		const SecureRequest &request,
-		crl::time msCanWait,
-		bool newRequest) {
+		crl::time msCanWait) {
 	DEBUG_LOG(("MTP Info: adding request to toSendMap, msCanWait %1"
 		).arg(msCanWait));
 	{
 		QWriteLocker locker(_data->toSendMutex());
 		_data->toSendMap().insert(request->requestId, request);
-
-		if (newRequest) {
-			*(mtpMsgId*)(request->data() + 4) = 0;
-			*(request->data() + 6) = 0;
-		}
+		*(mtpMsgId*)(request->data() + 4) = 0;
+		*(request->data() + 6) = 0;
 	}
 
 	DEBUG_LOG(("MTP Info: added, requestId %1").arg(request->requestId));
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index d7dd23b3d..896dafe4b 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -29,22 +29,6 @@ enum class CreatingKeyType;
 
 using PreRequestMap = QMap<mtpRequestId, SecureRequest>;
 using RequestMap = QMap<mtpMsgId, SecureRequest>;
-
-class RequestIdsMap : public QMap<mtpMsgId, mtpRequestId> {
-public:
-	using ParentType = QMap<mtpMsgId, mtpRequestId>;
-
-	mtpMsgId min() const {
-		return size() ? cbegin().key() : 0;
-	}
-
-	mtpMsgId max() const {
-		ParentType::const_iterator e(cend());
-		return size() ? (--e).key() : 0;
-	}
-
-};
-
 using SerializedMessage = mtpBuffer;
 
 inline bool ResponseNeedsAck(const SerializedMessage &response) {
@@ -102,12 +86,6 @@ public:
 	not_null<QReadWriteLock*> haveSentMutex() const {
 		return &_haveSentLock;
 	}
-	not_null<QReadWriteLock*> toResendMutex() const {
-		return &_toResendLock;
-	}
-	not_null<QReadWriteLock*> wereAckedMutex() const {
-		return &_wereAckedLock;
-	}
 	not_null<QReadWriteLock*> haveReceivedMutex() const {
 		return &_haveReceivedLock;
 	}
@@ -124,18 +102,6 @@ public:
 	const RequestMap &haveSentMap() const {
 		return _haveSent;
 	}
-	RequestIdsMap &toResendMap() { // msgId -> requestId, on which toSend: requestId -> request for resended requests
-		return _toResend;
-	}
-	const RequestIdsMap &toResendMap() const {
-		return _toResend;
-	}
-	RequestIdsMap &wereAckedMap() {
-		return _wereAcked;
-	}
-	const RequestIdsMap &wereAckedMap() const {
-		return _wereAcked;
-	}
 	QMap<mtpRequestId, SerializedMessage> &haveReceivedResponses() {
 		return _receivedResponses;
 	}
@@ -154,8 +120,6 @@ public:
 		return _owner;
 	}
 
-	void clearForNewKey(not_null<Instance*> instance);
-
 	// Connection -> Session interface.
 	void queueTryToReceive();
 	void queueNeedToResumeAndSend();
@@ -173,11 +137,6 @@ public:
 		const AuthKeyPtr &persistentKeyUsedForBind);
 	void releaseKeyCreationOnFail();
 	void destroyTemporaryKey(uint64 keyId);
-	void resend(
-		mtpMsgId msgId,
-		crl::time msCanWait,
-		bool forceContainer);
-	void resendAll();
 
 	void detach();
 
@@ -192,8 +151,6 @@ private:
 
 	PreRequestMap _toSend; // map of request_id -> request, that is waiting to be sent
 	RequestMap _haveSent; // map of msg_id -> request, that was sent, msDate = 0 for msgs_state_req (no resend / state req), msDate = 0, seqNo = 0 for containers
-	RequestIdsMap _toResend; // map of msg_id -> request_id, that request_id -> request lies in toSend and is waiting to be resent
-	RequestIdsMap _wereAcked; // map of msg_id -> request_id, this msg_ids already were acked or do not need ack
 
 	QMap<mtpRequestId, SerializedMessage> _receivedResponses; // map of request_id -> response that should be processed in the main thread
 	QList<SerializedMessage> _receivedUpdates; // list of updates that should be processed in the main thread
@@ -202,8 +159,6 @@ private:
 	mutable QReadWriteLock _optionsLock;
 	mutable QReadWriteLock _toSendLock;
 	mutable QReadWriteLock _haveSentLock;
-	mutable QReadWriteLock _toResendLock;
-	mutable QReadWriteLock _wereAckedLock;
 	mutable QReadWriteLock _haveReceivedLock;
 
 };
@@ -234,18 +189,7 @@ public:
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
 	[[nodiscard]] AuthKeyPtr getTemporaryKey(TemporaryKeyType type) const;
 	[[nodiscard]] bool connectionInited() const;
-	void resend(
-		mtpMsgId msgId,
-		crl::time msCanWait = 0,
-		bool forceContainer = false);
-	void resendAll();
-
-	// Thread-safe.
-	// Nulls msgId and seqNo in request, if newRequest = true.
-	void sendPrepared(
-		const SecureRequest &request,
-		crl::time msCanWait = 0,
-		bool newRequest = true);
+	void sendPrepared(const SecureRequest &request, crl::time msCanWait = 0);
 
 	// Connection thread.
 	[[nodiscard]] CreatingKeyType acquireKeyCreation(TemporaryKeyType type);

From 8be4dfb34625e05a0b1369e539ef68f56cac52d8 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 22 Nov 2019 12:15:38 +0300
Subject: [PATCH 47/91] Use explicit fields for sent container ids wrap.

---
 .../SourceFiles/mtproto/concurrent_sender.cpp |   2 +-
 .../SourceFiles/mtproto/concurrent_sender.h   |   9 +-
 Telegram/SourceFiles/mtproto/connection.cpp   | 322 ++++++++----------
 Telegram/SourceFiles/mtproto/connection.h     |  15 +-
 Telegram/SourceFiles/mtproto/core_types.h     |  96 ------
 .../details/mtproto_bound_key_creator.cpp     |   4 +-
 .../details/mtproto_bound_key_creator.h       |   4 +-
 .../mtproto/details/mtproto_dc_key_binder.cpp |   9 +-
 .../mtproto/details/mtproto_dc_key_binder.h   |   4 +-
 .../mtproto/details/mtproto_dump_to_text.h    |   1 +
 .../mtproto_serialized_request.cpp}           |  91 +++--
 .../details/mtproto_serialized_request.h      | 109 ++++++
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  31 +-
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   9 +-
 Telegram/SourceFiles/mtproto/session.cpp      |  83 ++---
 Telegram/SourceFiles/mtproto/session.h        |  66 ++--
 Telegram/gyp/lib_mtproto.gyp                  |   2 +
 Telegram/gyp/telegram/sources.txt             |   1 -
 Telegram/lib_tl                               |   2 +-
 19 files changed, 392 insertions(+), 468 deletions(-)
 rename Telegram/SourceFiles/mtproto/{core_types.cpp => details/mtproto_serialized_request.cpp} (55%)
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h

diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
index b2ffb0028..3d484296a 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
+++ b/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
@@ -111,7 +111,7 @@ auto ConcurrentSender::with_instance(Method &&method)
 
 ConcurrentSender::RequestBuilder::RequestBuilder(
 	not_null<ConcurrentSender*> sender,
-	SecureRequest &&serialized) noexcept
+	details::SerializedRequest &&serialized) noexcept
 : _sender(sender)
 , _serialized(std::move(serialized)) {
 }
diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.h b/Telegram/SourceFiles/mtproto/concurrent_sender.h
index 5929f800c..68fb22781 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.h
+++ b/Telegram/SourceFiles/mtproto/concurrent_sender.h
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/weak_ptr.h"
 #include "base/flat_map.h"
 #include "mtproto/core_types.h"
+#include "mtproto/details/mtproto_serialized_request.h"
 
 #ifndef _DEBUG
 #define MTP_SENDER_USE_GENERIC_HANDLERS
@@ -61,7 +62,7 @@ class ConcurrentSender : public base::has_weak_ptr {
 	protected:
 		RequestBuilder(
 			not_null<ConcurrentSender*> sender,
-			SecureRequest &&serialized) noexcept;
+			details::SerializedRequest &&serialized) noexcept;
 
 		void setToDC(ShiftedDcId dcId) noexcept;
 		void setCanWait(crl::time ms) noexcept;
@@ -74,7 +75,7 @@ class ConcurrentSender : public base::has_weak_ptr {
 
 	private:
 		not_null<ConcurrentSender*> _sender;
-		SecureRequest _serialized;
+		details::SerializedRequest _serialized;
 		ShiftedDcId _dcId = 0;
 		crl::time _canWait = 0;
 
@@ -224,8 +225,8 @@ void ConcurrentSender::RequestBuilder::setFailHandler(
 template <typename Request>
 ConcurrentSender::SpecificRequestBuilder<Request>::SpecificRequestBuilder(
 	not_null<ConcurrentSender*> sender,
-	Request &&request
-) noexcept : RequestBuilder(sender, SecureRequest::Serialize(request)) {
+	Request &&request) noexcept
+: RequestBuilder(sender, details::SerializedRequest::Serialize(request)) {
 }
 
 template <typename Request>
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index e5d5be76a..80f4e478e 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -85,11 +85,15 @@ using namespace details;
 		: TemporaryKeyType::Regular;
 }
 
-void wrapInvokeAfter(SecureRequest &to, const SecureRequest &from, const RequestMap &haveSent, int32 skipBeforeRequest = 0) {
+void WrapInvokeAfter(
+		SerializedRequest &to,
+		const SerializedRequest &from,
+		const base::flat_map<mtpMsgId, SerializedRequest> &haveSent,
+		int32 skipBeforeRequest = 0) {
 	const auto afterId = *(mtpMsgId*)(from->after->data() + 4);
-	const auto i = afterId ? haveSent.constFind(afterId) : haveSent.cend();
+	const auto i = afterId ? haveSent.find(afterId) : haveSent.end();
 	int32 size = to->size(), lenInInts = (tl::count_length(from) >> 2), headlen = 4, fulllen = headlen + lenInInts;
-	if (i == haveSent.constEnd()) { // no invoke after or such msg was not sent or was completed recently
+	if (i == haveSent.end()) { // no invoke after or such msg was not sent or was completed recently
 		to->resize(size + fulllen + skipBeforeRequest);
 		if (skipBeforeRequest) {
 			memcpy(to->data() + size, from->constData() + 4, headlen * sizeof(mtpPrime));
@@ -229,41 +233,41 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 }
 
 void ConnectionPrivate::checkSentRequests() {
-	QVector<mtpMsgId> removingIds; // remove very old (10 minutes) containers and resend requests
+	// Remove very old (10 minutes) containers and resend requests.
+	auto removingIds = std::vector<mtpMsgId>();
 	auto requesting = false;
 	{
 		QReadLocker locker(_sessionData->haveSentMutex());
 		auto &haveSent = _sessionData->haveSentMap();
 		const auto haveSentCount = haveSent.size();
-		auto ms = crl::now();
-		for (auto i = haveSent.begin(), e = haveSent.end(); i != e; ++i) {
-			auto &req = i.value();
-			if (req->msDate > 0) {
-				if (req->msDate + kCheckSentRequestTimeout < ms) {
-					// Need to check state.
-					req->msDate = ms;
-					if (_stateRequestData.emplace(i.key()).second) {
-						requesting = true;
-					}
+		auto now = crl::now();
+		for (const auto &[msgId, request] : haveSent) {
+			if (request.isStateRequest()) {
+				continue;
+			} else if (request.isSentContainer()) {
+				if (base::unixtime::now()
+					> int32(msgId >> 32) + kContainerLives) {
+					removingIds.push_back(msgId);
+				}
+			} else if (request->lastSentTime + kCheckSentRequestTimeout
+				< now) {
+				// Need to check state.
+				request->lastSentTime = now;
+				if (_stateRequestData.emplace(msgId).second) {
+					requesting = true;
 				}
-			} else if (base::unixtime::now()
-				> int32(i.key() >> 32) + kContainerLives) {
-				removingIds.reserve(haveSentCount);
-				removingIds.push_back(i.key());
 			}
 		}
 	}
 	if (requesting) {
 		_sessionData->queueSendAnything(kSendStateRequestWaiting);
 	}
-	if (!removingIds.isEmpty()) {
+	if (!removingIds.empty()) {
 		QWriteLocker locker(_sessionData->haveSentMutex());
 		auto &haveSent = _sessionData->haveSentMap();
-		for (uint32 i = 0, l = removingIds.size(); i < l; ++i) {
-			auto j = haveSent.find(removingIds[i]);
-			if (j != haveSent.cend()) {
-				Assert(!j.value()->requestId);
-				haveSent.erase(j);
+		for (const auto msgId : removingIds) {
+			if (const auto removed = haveSent.take(msgId)) {
+				Assert(!(*removed)->requestId);
 			}
 		}
 	}
@@ -436,7 +440,7 @@ bool ConnectionPrivate::markSessionAsStarted() {
 }
 
 mtpMsgId ConnectionPrivate::prepareToSend(
-		SecureRequest &request,
+		SerializedRequest &request,
 		mtpMsgId currentLastId,
 		bool forceNewMsgId) {
 	Expects(request->size() > 8);
@@ -460,7 +464,7 @@ mtpMsgId ConnectionPrivate::prepareToSend(
 	return currentLastId;
 }
 
-mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId) {
+mtpMsgId ConnectionPrivate::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
 	Expects(request->size() > 8);
 
 	const auto oldMsgId = request.getMsgId();
@@ -472,11 +476,14 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 
 	while (_resendingIds.contains(newId)
 		|| _ackedIds.contains(newId)
-		|| haveSent.constFind(newId) != haveSent.cend()) {
+		|| haveSent.contains(newId)) {
 		newId = base::unixtime::mtproto_msg_id();
 	}
 
-	MTP_LOG(_shiftedDcId, ("[r%1] msg_id %2 -> %3").arg(request->requestId).arg(oldMsgId).arg(newId));
+	MTP_LOG(_shiftedDcId, ("[r%1] msg_id %2 -> %3"
+		).arg(request->requestId
+		).arg(oldMsgId
+		).arg(newId));
 
 	const auto i = _resendingIds.find(oldMsgId);
 	if (i != _resendingIds.end()) {
@@ -486,24 +493,23 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 	}
 
 	const auto j = _ackedIds.find(oldMsgId);
-	if (j != _ackedIds.cend()) {
+	if (j != _ackedIds.end()) {
 		const auto requestId = j->second;
 		_ackedIds.erase(j);
 		_ackedIds.emplace(newId, requestId);
 	}
 
 	const auto k = haveSent.find(oldMsgId);
-	if (k != haveSent.cend()) {
-		const auto req = k.value();
+	if (k != haveSent.end()) {
+		const auto request = k->second;
 		haveSent.erase(k);
-		haveSent.insert(newId, req);
+		haveSent.emplace(newId, request);
 	}
 
-	for (auto l = haveSent.begin(); l != haveSent.cend(); ++l) {
-		const auto req = l.value();
-		if (req.isSentContainer()) {
-			const auto ids = (mtpMsgId *)(req->data() + 8);
-			for (uint32 i = 0, l = (req->size() - 8) >> 1; i < l; ++i) {
+	for (const auto &[requestId, sent] : haveSent) {
+		if (sent.isSentContainer()) {
+			const auto ids = (mtpMsgId *)(sent->data() + 8);
+			for (uint32 i = 0, l = (sent->size() - 8) >> 1; i < l; ++i) {
 				if (ids[i] == oldMsgId) {
 					ids[i] = newId;
 				}
@@ -517,11 +523,11 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SecureRequest &request, mtpMsgId newId)
 }
 
 mtpMsgId ConnectionPrivate::placeToContainer(
-		SecureRequest &toSendRequest,
+		SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
 		mtpMsgId *&haveSentArr,
-		SecureRequest &req) {
+		SerializedRequest &req) {
 	const auto msgId = prepareToSend(req, bigMsgId, forceNewMsgId);
 	if (msgId >= bigMsgId) {
 		bigMsgId = base::unixtime::mtproto_msg_id();
@@ -560,28 +566,28 @@ void ConnectionPrivate::tryToSend() {
 		_keyCreator->restartBinder();
 	}
 
-	auto pingRequest = SecureRequest();
-	auto ackRequest = SecureRequest();
-	auto resendRequest = SecureRequest();
-	auto stateRequest = SecureRequest();
-	auto httpWaitRequest = SecureRequest();
-	auto bindDcKeyRequest = SecureRequest();
+	auto pingRequest = SerializedRequest();
+	auto ackRequest = SerializedRequest();
+	auto resendRequest = SerializedRequest();
+	auto stateRequest = SerializedRequest();
+	auto httpWaitRequest = SerializedRequest();
+	auto bindDcKeyRequest = SerializedRequest();
 	if (_pingIdToSend) {
 		if (sendOnlyFirstPing || !isMainSession) {
 			DEBUG_LOG(("MTP Info: sending ping, ping_id: %1"
 				).arg(_pingIdToSend));
-			pingRequest = SecureRequest::Serialize(MTPPing(
+			pingRequest = SerializedRequest::Serialize(MTPPing(
 				MTP_long(_pingIdToSend)
 			));
 		} else {
 			DEBUG_LOG(("MTP Info: sending ping_delay_disconnect, "
 				"ping_id: %1").arg(_pingIdToSend));
-			pingRequest = SecureRequest::Serialize(MTPPing_delay_disconnect(
+			pingRequest = SerializedRequest::Serialize(MTPPing_delay_disconnect(
 				MTP_long(_pingIdToSend),
 				MTP_int(kPingDelayDisconnect)));
 			_pingSender.callOnce(kPingSendAfterForce);
 		}
-		_pingSendAt = pingRequest->msDate + kPingSendAfter;
+		_pingSendAt = pingRequest->lastSentTime + kPingSendAfter;
 		_pingId = base::take(_pingIdToSend);
 	} else if (!sendAll) {
 		DEBUG_LOG(("MTP Info: dc %1 sending only service or bind."
@@ -594,12 +600,12 @@ void ConnectionPrivate::tryToSend() {
 
 	if (!sendOnlyFirstPing) {
 		if (!_ackRequestData.isEmpty()) {
-			ackRequest = SecureRequest::Serialize(MTPMsgsAck(
+			ackRequest = SerializedRequest::Serialize(MTPMsgsAck(
 				MTP_msgs_ack(MTP_vector<MTPlong>(
 					base::take(_ackRequestData)))));
 		}
 		if (!_resendRequestData.isEmpty()) {
-			resendRequest = SecureRequest::Serialize(MTPMsgResendReq(
+			resendRequest = SerializedRequest::Serialize(MTPMsgResendReq(
 				MTP_msg_resend_req(MTP_vector<MTPlong>(
 					base::take(_resendRequestData)))));
 		}
@@ -609,13 +615,13 @@ void ConnectionPrivate::tryToSend() {
 			for (const auto id : base::take(_stateRequestData)) {
 				ids.push_back(MTP_long(id));
 			}
-			stateRequest = SecureRequest::Serialize(MTPMsgsStateReq(
+			stateRequest = SerializedRequest::Serialize(MTPMsgsStateReq(
 				MTP_msgs_state_req(MTP_vector<MTPlong>(ids))));
 			// Add to haveSent / _ackedIds, but don't add to requestMap.
 			stateRequest->requestId = GetNextRequestId();
 		}
 		if (_connection->usingHttpWait()) {
-			httpWaitRequest = SecureRequest::Serialize(MTPHttpWait(
+			httpWaitRequest = SerializedRequest::Serialize(MTPHttpWait(
 				MTP_http_wait(MTP_int(100), MTP_int(30), MTP_int(25000))));
 		}
 		if (!_bindMsgId && _keyCreator && _keyCreator->readyToBind()) {
@@ -631,7 +637,7 @@ void ConnectionPrivate::tryToSend() {
 		}
 	}
 
-	MTPInitConnection<SecureRequest> initWrapper;
+	MTPInitConnection<SerializedRequest> initWrapper;
 	int32 initSize = 0, initSizeInInts = 0;
 	if (needsLayer) {
 		Assert(_connectionOptions != nullptr);
@@ -660,8 +666,8 @@ void ConnectionPrivate::tryToSend() {
 				MTP_string(_connectionOptions->proxy.host),
 				MTP_int(_connectionOptions->proxy.port))
 			: MTPInputClientProxy();
-		using Flag = MTPInitConnection<SecureRequest>::Flag;
-		initWrapper = MTPInitConnection<SecureRequest>(
+		using Flag = MTPInitConnection<SerializedRequest>::Flag;
+		initWrapper = MTPInitConnection<SerializedRequest>(
 			MTP_flags(mtprotoProxy ? Flag::f_proxy : Flag(0)),
 			MTP_int(ApiId),
 			MTP_string(deviceModel),
@@ -671,25 +677,22 @@ void ConnectionPrivate::tryToSend() {
 			MTP_string(langPackName),
 			MTP_string(cloudLangCode),
 			clientProxyFields,
-			SecureRequest());
+			SerializedRequest());
 		initSizeInInts = (tl::count_length(initWrapper) >> 2) + 2;
 		initSize = initSizeInInts * sizeof(mtpPrime);
 	}
 
 	bool needAnyResponse = false;
-	SecureRequest toSendRequest;
+	SerializedRequest toSendRequest;
 	{
 		QWriteLocker locker1(_sessionData->toSendMutex());
 
-		auto toSendDummy = PreRequestMap();
+		auto toSendDummy = base::flat_map<mtpRequestId, SerializedRequest>();
 		auto &toSend = sendAll
 			? _sessionData->toSendMap()
 			: toSendDummy;
 		if (!sendAll) {
 			locker1.unlock();
-		} else {
-			int time = crl::now();
-			int now = crl::now();
 		}
 
 		uint32 toSendCount = toSend.size();
@@ -716,8 +719,8 @@ void ConnectionPrivate::tryToSend() {
 			? httpWaitRequest
 			: bindDcKeyRequest
 			? bindDcKeyRequest
-			: toSend.cbegin().value();
-		if (toSendCount == 1 && first->msDate > 0) { // if can send without container
+			: toSend.begin()->second;
+		if (toSendCount == 1 && !first->forceSendInContainer) {
 			toSendRequest = first;
 			if (sendAll) {
 				toSend.clear();
@@ -740,27 +743,27 @@ void ConnectionPrivate::tryToSend() {
 
 			if (toSendRequest->requestId) {
 				if (toSendRequest.needAck()) {
-					toSendRequest->msDate = toSendRequest.isStateRequest() ? 0 : crl::now();
+					toSendRequest->lastSentTime = crl::now();
 
 					QWriteLocker locker2(_sessionData->haveSentMutex());
 					auto &haveSent = _sessionData->haveSentMap();
-					haveSent.insert(msgId, toSendRequest);
+					haveSent.emplace(msgId, toSendRequest);
 
 					const auto wrapLayer = needsLayer && toSendRequest->needsLayer;
 					if (toSendRequest->after) {
 						const auto toSendSize = tl::count_length(toSendRequest) >> 2;
-						auto wrappedRequest = SecureRequest::Prepare(
+						auto wrappedRequest = SerializedRequest::Prepare(
 							toSendSize,
 							toSendSize + 3);
 						wrappedRequest->resize(4);
 						memcpy(wrappedRequest->data(), toSendRequest->constData(), 4 * sizeof(mtpPrime));
-						wrapInvokeAfter(wrappedRequest, toSendRequest, haveSent);
+						WrapInvokeAfter(wrappedRequest, toSendRequest, haveSent);
 						toSendRequest = std::move(wrappedRequest);
 					}
 					if (wrapLayer) {
 						const auto noWrapSize = (tl::count_length(toSendRequest) >> 2);
 						const auto toSendSize = noWrapSize + initSizeInInts;
-						auto wrappedRequest = SecureRequest::Prepare(toSendSize);
+						auto wrappedRequest = SerializedRequest::Prepare(toSendSize);
 						memcpy(wrappedRequest->data(), toSendRequest->constData(), 7 * sizeof(mtpPrime)); // all except length
 						wrappedRequest->push_back(mtpc_invokeWithLayer);
 						wrappedRequest->push_back(internal::CurrentLayer);
@@ -784,9 +787,9 @@ void ConnectionPrivate::tryToSend() {
 			if (stateRequest) containerSize += stateRequest.messageSize();
 			if (httpWaitRequest) containerSize += httpWaitRequest.messageSize();
 			if (bindDcKeyRequest) containerSize += bindDcKeyRequest.messageSize();
-			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
-				containerSize += i.value().messageSize();
-				if (needsLayer && i.value()->needsLayer) {
+			for (const auto &[requestId, request] : toSend) {
+				containerSize += request.messageSize();
+				if (needsLayer && request->needsLayer) {
 					containerSize += initSizeInInts;
 					willNeedInit = true;
 				}
@@ -799,7 +802,7 @@ void ConnectionPrivate::tryToSend() {
 				initWrapper.write<mtpBuffer>(initSerialized);
 			}
 			// prepare container + each in invoke after
-			toSendRequest = SecureRequest::Prepare(
+			toSendRequest = SerializedRequest::Prepare(
 				containerSize,
 				containerSize + 3 * toSend.size());
 			toSendRequest->push_back(mtpc_msg_container);
@@ -813,9 +816,8 @@ void ConnectionPrivate::tryToSend() {
 			auto &haveSent = _sessionData->haveSentMap();
 
 			// prepare "request-like" wrap for msgId vector
-			auto haveSentIdsWrap = SecureRequest::Prepare(idsWrapSize);
-			haveSentIdsWrap->msDate = 0; // Container: msDate = 0, seqNo = 0.
-			haveSentIdsWrap->requestId = 0;
+			auto haveSentIdsWrap = SerializedRequest::Prepare(idsWrapSize);
+			haveSentIdsWrap->isContainerIdsWrap = true;
 			haveSentIdsWrap->resize(haveSentIdsWrap->size() + idsWrapSize);
 			auto haveSentArr = (mtpMsgId*)(haveSentIdsWrap->data() + 8);
 
@@ -840,10 +842,9 @@ void ConnectionPrivate::tryToSend() {
 			if (resendRequest || stateRequest) {
 				needAnyResponse = true;
 			}
-			for (auto i = toSend.begin(), e = toSend.end(); i != e; ++i) {
-				auto &req = i.value();
+			for (auto &[requestId, request] : toSend) {
 				const auto msgId = prepareToSend(
-					req,
+					request,
 					bigMsgId,
 					forceNewMsgId);
 				if (msgId >= bigMsgId) {
@@ -851,44 +852,43 @@ void ConnectionPrivate::tryToSend() {
 				}
 				*(haveSentArr++) = msgId;
 				bool added = false;
-				if (req->requestId) {
-					if (req.needAck()) {
-						req->msDate = req.isStateRequest() ? 0 : crl::now();
-						int32 reqNeedsLayer = (needsLayer && req->needsLayer) ? toSendRequest->size() : 0;
-						if (req->after) {
-							wrapInvokeAfter(toSendRequest, req, haveSent, reqNeedsLayer ? initSizeInInts : 0);
+				if (request->requestId) {
+					if (request.needAck()) {
+						request->lastSentTime = crl::now();
+						int32 reqNeedsLayer = (needsLayer && request->needsLayer) ? toSendRequest->size() : 0;
+						if (request->after) {
+							WrapInvokeAfter(toSendRequest, request, haveSent, reqNeedsLayer ? initSizeInInts : 0);
 							if (reqNeedsLayer) {
 								memcpy(toSendRequest->data() + reqNeedsLayer + 4, initSerialized.constData(), initSize);
 								*(toSendRequest->data() + reqNeedsLayer + 3) += initSize;
 							}
 							added = true;
 						} else if (reqNeedsLayer) {
-							toSendRequest->resize(reqNeedsLayer + initSizeInInts + req.messageSize());
-							memcpy(toSendRequest->data() + reqNeedsLayer, req->constData() + 4, 4 * sizeof(mtpPrime));
+							toSendRequest->resize(reqNeedsLayer + initSizeInInts + request.messageSize());
+							memcpy(toSendRequest->data() + reqNeedsLayer, request->constData() + 4, 4 * sizeof(mtpPrime));
 							memcpy(toSendRequest->data() + reqNeedsLayer + 4, initSerialized.constData(), initSize);
-							memcpy(toSendRequest->data() + reqNeedsLayer + 4 + initSizeInInts, req->constData() + 8, tl::count_length(req));
+							memcpy(toSendRequest->data() + reqNeedsLayer + 4 + initSizeInInts, request->constData() + 8, tl::count_length(request));
 							*(toSendRequest->data() + reqNeedsLayer + 3) += initSize;
 							added = true;
 						}
 						Assert(!haveSent.contains(msgId));
-						haveSent.insert(msgId, req);
+						haveSent.emplace(msgId, request);
 
 						needAnyResponse = true;
 					} else {
-						_ackedIds.emplace(msgId, req->requestId);
+						_ackedIds.emplace(msgId, request->requestId);
 					}
 				}
 				if (!added) {
-					uint32 from = toSendRequest->size(), len = req.messageSize();
+					uint32 from = toSendRequest->size(), len = request.messageSize();
 					toSendRequest->resize(from + len);
-					memcpy(toSendRequest->data() + from, req->constData() + 4, len * sizeof(mtpPrime));
+					memcpy(toSendRequest->data() + from, request->constData() + 4, len * sizeof(mtpPrime));
 				}
 			}
 			if (stateRequest) {
-				mtpMsgId msgId = placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, stateRequest);
-				stateRequest->msDate = 0; // 0 for state request, do not request state of it
+				const auto msgId = placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, stateRequest);
 				Assert(!haveSent.contains(msgId));
-				haveSent.insert(msgId, stateRequest);
+				haveSent.emplace(msgId, stateRequest);
 			}
 			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, resendRequest);
 			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, ackRequest);
@@ -899,9 +899,8 @@ void ConnectionPrivate::tryToSend() {
 				bigMsgId,
 				forceNewMsgId);
 			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = containerMsgId;
-			(*haveSentIdsWrap)[6] = 0; // for container, msDate = 0, seqNo = 0
 			Assert(!haveSent.contains(containerMsgId));
-			haveSent.insert(containerMsgId, haveSentIdsWrap);
+			haveSent.emplace(containerMsgId, haveSentIdsWrap);
 			toSend.clear();
 		}
 	}
@@ -1370,7 +1369,8 @@ void ConnectionPrivate::handleReceived() {
 		}
 
 		auto lock = QReadLocker(_sessionData->haveReceivedMutex());
-		const auto tryToReceive = !_sessionData->haveReceivedResponses().isEmpty() || !_sessionData->haveReceivedUpdates().isEmpty();
+		const auto tryToReceive = !_sessionData->haveReceivedResponses().empty()
+			|| !_sessionData->haveReceivedUpdates().empty();
 		lock.unlock();
 
 		if (tryToReceive) {
@@ -1521,16 +1521,16 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 				|| (errorCode == 64); // bad container
 			if (errorCode == 64) { // bad container!
 				if (Logs::DebugEnabled()) {
-					SecureRequest request;
+					SerializedRequest request;
 					{
 						QWriteLocker locker(_sessionData->haveSentMutex());
 						auto &haveSent = _sessionData->haveSentMap();
 
-						const auto i = haveSent.constFind(resendId);
-						if (i == haveSent.cend()) {
+						const auto i = haveSent.find(resendId);
+						if (i == haveSent.end()) {
 							LOG(("Message Error: Container not found!"));
 						} else {
-							request = i.value();
+							request = i->second;
 						}
 					}
 					if (request) {
@@ -1626,53 +1626,6 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 		resend(resendId);
 	} return HandleResult::Success;
 
-	case mtpc_msgs_state_req: {
-		if (badTime) {
-			DEBUG_LOG(("Message Info: skipping with bad time..."));
-			return HandleResult::Ignored;
-		}
-		MTPMsgsStateReq msg;
-		if (!msg.read(from, end)) {
-			return HandleResult::ParseError;
-		}
-		auto &ids = msg.c_msgs_state_req().vmsg_ids().v;
-		auto idsCount = ids.size();
-		DEBUG_LOG(("Message Info: msgs_state_req received, ids: %1").arg(LogIdsVector(ids)));
-		if (!idsCount) return HandleResult::Success;
-
-		QByteArray info(idsCount, Qt::Uninitialized);
-		{
-			const auto minRecv = _receivedMessageIds.min();
-			const auto maxRecv = _receivedMessageIds.max();
-			for (uint32 i = 0, l = idsCount; i < l; ++i) {
-				char state = 0;
-				uint64 reqMsgId = ids[i].v;
-				if (reqMsgId < minRecv) {
-					state |= 0x01;
-				} else if (reqMsgId > maxRecv) {
-					state |= 0x03;
-				} else {
-					auto msgIdState = _receivedMessageIds.lookup(reqMsgId);
-					if (msgIdState == ReceivedIdsManager::State::NotFound) {
-						state |= 0x02;
-					} else {
-						state |= 0x04;
-						if (_ackedIds.contains(reqMsgId)) {
-							state |= 0x80; // we know, that server knows, that we received request
-						}
-						if (msgIdState == ReceivedIdsManager::State::NeedsAck) { // need ack, so we sent ack
-							state |= 0x08;
-						} else {
-							state |= 0x10;
-						}
-					}
-				}
-				info[i] = state;
-			}
-		}
-		_sessionData->queueSendMsgsStateInfo(msgId, info);
-	} return HandleResult::Success;
-
 	case mtpc_msgs_state_info: {
 		MTPMsgsStateInfo msg;
 		if (!msg.read(from, end)) {
@@ -1684,12 +1637,12 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 		auto &states = data.vinfo().v;
 
 		DEBUG_LOG(("Message Info: msg state received, msgId %1, reqMsgId: %2, HEX states %3").arg(msgId).arg(reqMsgId).arg(Logs::mb(states.data(), states.length()).str()));
-		SecureRequest requestBuffer;
+		SerializedRequest requestBuffer;
 		{ // find this request in session-shared sent requests map
 			QReadLocker locker(_sessionData->haveSentMutex());
 			const auto &haveSent = _sessionData->haveSentMap();
-			const auto replyTo = haveSent.constFind(reqMsgId);
-			if (replyTo == haveSent.cend()) { // do not look in toResend, because we do not resend msgs_state_req requests
+			const auto replyTo = haveSent.find(reqMsgId);
+			if (replyTo == haveSent.end()) { // do not look in toResend, because we do not resend msgs_state_req requests
 				DEBUG_LOG(("Message Error: such message was not sent recently %1").arg(reqMsgId));
 				return (badTime ? HandleResult::Ignored : HandleResult::Success);
 			}
@@ -1703,7 +1656,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 
 				badTime = false;
 			}
-			requestBuffer = replyTo.value();
+			requestBuffer = replyTo->second;
 		}
 		QVector<MTPlong> toAckReq(1, MTP_long(reqMsgId)), toAck;
 		requestsAcked(toAck, true);
@@ -1809,7 +1762,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 		if (from + 3 > end) {
 			return HandleResult::ParseError;
 		}
-		auto response = SerializedMessage();
+		auto response = mtpBuffer();
 
 		MTPlong reqMsgId;
 		if (!reqMsgId.read(++from, end)) {
@@ -1861,7 +1814,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 		if (requestId && requestId != mtpRequestId(0xFFFFFFFF)) {
 			// Save rpc_result for processing in the main thread.
 			QWriteLocker locker(_sessionData->haveReceivedMutex());
-			_sessionData->haveReceivedResponses().insert(requestId, response);
+			_sessionData->haveReceivedResponses().emplace(requestId, response);
 		} else {
 			DEBUG_LOG(("RPC Info: requestId not found for msgId %1").arg(requestMsgId));
 		}
@@ -1893,11 +1846,11 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 			QReadLocker locker(_sessionData->haveSentMutex());
 			const auto &haveSent = _sessionData->haveSentMap();
 			toResend.reserve(haveSent.size());
-			for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
-				if (i.key() >= firstMsgId) {
+			for (const auto &[msgId, request] : haveSent) {
+				if (msgId >= firstMsgId) {
 					break;
-				} else if (i.value()->requestId) {
-					toResend.push_back(i.key());
+				} else if (request->requestId) {
+					toResend.push_back(msgId);
 				}
 			}
 		}
@@ -1910,7 +1863,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 
 		// Notify main process about new session - need to get difference.
 		QWriteLocker locker(_sessionData->haveReceivedMutex());
-		_sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
+		_sessionData->haveReceivedUpdates().push_back(mtpBuffer(update));
 	} return HandleResult::Success;
 
 	case mtpc_pong: {
@@ -1957,7 +1910,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 
 		// Notify main process about the new updates.
 		QWriteLocker locker(_sessionData->haveReceivedMutex());
-		_sessionData->haveReceivedUpdates().push_back(SerializedMessage(update));
+		_sessionData->haveReceivedUpdates().push_back(mtpBuffer(update));
 	} else {
 		LOG(("Message Error: unexpected updates in dcType: %1"
 			).arg(static_cast<int>(_currentDcType)));
@@ -2075,27 +2028,27 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 		for (uint32 i = 0; i < idsCount; ++i) {
 			mtpMsgId msgId = ids[i].v;
 			const auto req = haveSent.find(msgId);
-			if (req != haveSent.cend()) {
-				if (!req.value()->msDate) {
+			if (req != haveSent.end()) {
+				if (req->second.isSentContainer()) {
 					DEBUG_LOG(("Message Info: container ack received, msgId %1").arg(ids[i].v));
-					uint32 inContCount = ((*req)->size() - 8) / 2;
-					const mtpMsgId *inContId = (const mtpMsgId *)(req.value()->constData() + 8);
+					uint32 inContCount = (req->second->size() - 8) / 2;
+					const mtpMsgId *inContId = (const mtpMsgId *)(req->second->constData() + 8);
 					toAckMore.reserve(toAckMore.size() + inContCount);
 					for (uint32 j = 0; j < inContCount; ++j) {
 						toAckMore.push_back(MTP_long(*(inContId++)));
 					}
 					haveSent.erase(req);
 				} else {
-					mtpRequestId reqId = req.value()->requestId;
+					const auto requestId = req->second->requestId;
 					bool moveToAcked = byResponse;
 					if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
-						moveToAcked = !_instance->hasCallbacks(reqId);
+						moveToAcked = !_instance->hasCallbacks(requestId);
 					}
 					if (moveToAcked) {
-						_ackedIds.emplace(msgId, reqId);
+						_ackedIds.emplace(msgId, requestId);
 						haveSent.erase(req);
 					} else {
-						DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(reqId));
+						DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(requestId));
 					}
 				}
 			} else {
@@ -2112,9 +2065,9 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 						auto &toSend = _sessionData->toSendMap();
 						const auto req = toSend.find(reqId);
 						if (req != toSend.cend()) {
-							_ackedIds.emplace(msgId, req.value()->requestId);
-							if (req.value()->requestId != reqId) {
-								DEBUG_LOG(("Message Error: for msgId %1 found resent request, requestId %2, contains requestId %3").arg(msgId).arg(reqId).arg(req.value()->requestId));
+							_ackedIds.emplace(msgId, req->second->requestId);
+							if (req->second->requestId != reqId) {
+								DEBUG_LOG(("Message Error: for msgId %1 found resent request, requestId %2, contains requestId %3").arg(msgId).arg(reqId).arg(req->second->requestId));
 							} else {
 								DEBUG_LOG(("Message Info: acked msgId %1 that was prepared to resend, requestId %2").arg(msgId).arg(reqId));
 							}
@@ -2172,9 +2125,7 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 		uint64 requestMsgId = ids[i].v;
 		{
 			QReadLocker locker(_sessionData->haveSentMutex());
-			const auto &haveSent = _sessionData->haveSentMap();
-			const auto haveSentEnd = haveSent.cend();
-			if (haveSent.find(requestMsgId) == haveSentEnd) {
+			if (!_sessionData->haveSentMap().contains(requestMsgId)) {
 				DEBUG_LOG(("Message Info: state was received for msgId %1, but request is not found, looking in resent requests...").arg(requestMsgId));
 				const auto reqIt = _resendingIds.find(requestMsgId);
 				if (reqIt != _resendingIds.cend()) {
@@ -2226,7 +2177,7 @@ void ConnectionPrivate::resend(
 	if (i == haveSent.end()) {
 		return;
 	}
-	auto request = i.value();
+	auto request = i->second;
 	haveSent.erase(i);
 	lock.unlock();
 
@@ -2238,11 +2189,12 @@ void ConnectionPrivate::resend(
 			resend(ids[i], -1, true);
 		}
 	} else if (!request.isStateRequest()) {
-		request->msDate = forceContainer ? 0 : crl::now();
+		request->lastSentTime = crl::now();
+		request->forceSendInContainer = forceContainer;
 		_resendingIds.emplace(msgId, request->requestId);
 		{
 			QWriteLocker locker(_sessionData->toSendMutex());
-			_sessionData->toSendMap().insert(request->requestId, request);
+			_sessionData->toSendMap().emplace(request->requestId, request);
 		}
 	}
 }
@@ -2253,9 +2205,9 @@ void ConnectionPrivate::resendAll() {
 	auto lock = QReadLocker(_sessionData->haveSentMutex());
 	const auto &haveSent = _sessionData->haveSentMap();
 	toResend.reserve(haveSent.size());
-	for (auto i = haveSent.cbegin(), e = haveSent.cend(); i != e; ++i) {
-		if (!i.value().isSentContainer()) {
-			toResend.push_back(i.key());
+	for (const auto &[msgId, request] : haveSent) {
+		if (!request.isSentContainer() && !request.isStateRequest()) {
+			toResend.push_back(msgId);
 		}
 	}
 	lock.unlock();
@@ -2581,7 +2533,7 @@ void ConnectionPrivate::destroyTemporaryKey() {
 }
 
 bool ConnectionPrivate::sendSecureRequest(
-		SecureRequest &&request,
+		SerializedRequest &&request,
 		bool needAnyResponse) {
 #ifdef TDESKTOP_MTPROTO_OLD
 	const auto oldPadding = true;
@@ -2671,10 +2623,10 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 	{
 		QReadLocker locker(_sessionData->haveSentMutex());
 		const auto &haveSent = _sessionData->haveSentMap();
-		const auto i = haveSent.constFind(msgId);
-		if (i != haveSent.cend()) {
-			return i.value()->requestId
-				? i.value()->requestId
+		const auto i = haveSent.find(msgId);
+		if (i != haveSent.end()) {
+			return i->second->requestId
+				? i->second->requestId
 				: mtpRequestId(0xFFFFFFFF);
 		}
 	}
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 36c5706d3..2715bb640 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/details/mtproto_received_ids_manager.h"
+#include "mtproto/details/mtproto_serialized_request.h"
 #include "mtproto/mtproto_auth_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/connection_abstract.h"
@@ -139,18 +140,22 @@ private:
 	void checkSentRequests();
 
 	mtpMsgId placeToContainer(
-		SecureRequest &toSendRequest,
+		details::SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
 		mtpMsgId *&haveSentArr,
-		SecureRequest &req);
+		details::SerializedRequest &req);
 	mtpMsgId prepareToSend(
-		SecureRequest &request,
+		details::SerializedRequest &request,
 		mtpMsgId currentLastId,
 		bool forceNewMsgId);
-	mtpMsgId replaceMsgId(SecureRequest &request, mtpMsgId newId);
+	mtpMsgId replaceMsgId(
+		details::SerializedRequest &request,
+		mtpMsgId newId);
 
-	bool sendSecureRequest(SecureRequest &&request, bool needAnyResponse);
+	bool sendSecureRequest(
+		details::SerializedRequest &&request,
+		bool needAnyResponse);
 	mtpRequestId wasSent(mtpMsgId msgId) const;
 
 	[[nodiscard]] HandleResult handleOneReceived(const mtpPrime *from, const mtpPrime *end, uint64 msgId, int32 serverTime, uint64 serverSalt, bool badTime);
diff --git a/Telegram/SourceFiles/mtproto/core_types.h b/Telegram/SourceFiles/mtproto/core_types.h
index 37c84a16d..93724f611 100644
--- a/Telegram/SourceFiles/mtproto/core_types.h
+++ b/Telegram/SourceFiles/mtproto/core_types.h
@@ -122,102 +122,6 @@ static const mtpTypeId mtpLayers[] = {
 };
 static const uint32 mtpLayerMaxSingle = sizeof(mtpLayers) / sizeof(mtpLayers[0]);
 
-namespace MTP {
-namespace details {
-
-struct SecureRequestCreateTag {
-};
-
-} // namespace details
-
-class SecureRequestData;
-class SecureRequest {
-public:
-	SecureRequest() = default;
-
-	static constexpr auto kSaltInts = 2;
-	static constexpr auto kSessionIdInts = 2;
-	static constexpr auto kMessageIdPosition = kSaltInts + kSessionIdInts;
-	static constexpr auto kMessageIdInts = 2;
-	static constexpr auto kSeqNoPosition = kMessageIdPosition
-		+ kMessageIdInts;
-	static constexpr auto kSeqNoInts = 1;
-	static constexpr auto kMessageLengthPosition = kSeqNoPosition
-		+ kSeqNoInts;
-	static constexpr auto kMessageLengthInts = 1;
-	static constexpr auto kMessageBodyPosition = kMessageLengthPosition
-		+ kMessageLengthInts;
-
-	static SecureRequest Prepare(uint32 size, uint32 reserveSize = 0);
-
-	template <
-		typename Request,
-		typename = std::enable_if_t<tl::is_boxed_v<Request>>>
-	static SecureRequest Serialize(const Request &request);
-
-	// For template MTP requests and MTPBoxed instanciation.
-	template <typename Accumulator>
-	void write(Accumulator &to) const {
-		if (const auto size = sizeInBytes()) {
-			tl::Writer<Accumulator>::PutBytes(to, dataInBytes(), size);
-		}
-	}
-
-	SecureRequestData *operator->() const;
-	SecureRequestData &operator*() const;
-	explicit operator bool() const;
-
-	void setMsgId(mtpMsgId msgId);
-	[[nodiscard]] mtpMsgId getMsgId() const;
-
-	void setSeqNo(uint32 seqNo);
-	[[nodiscard]] uint32 getSeqNo() const;
-
-	void addPadding(bool extended, bool old);
-	[[nodiscard]] uint32 messageSize() const;
-
-	// "request-like" wrap for msgIds vector
-	[[nodiscard]] bool isSentContainer() const;
-	[[nodiscard]] bool isStateRequest() const;
-	[[nodiscard]] bool needAck() const;
-
-	using ResponseType = void; // don't know real response type =(
-
-private:
-	explicit SecureRequest(const details::SecureRequestCreateTag &);
-
-	[[nodiscard]] size_t sizeInBytes() const;
-	[[nodiscard]] const void *dataInBytes() const;
-
-	std::shared_ptr<SecureRequestData> _data;
-
-};
-
-class SecureRequestData : public mtpBuffer {
-public:
-	explicit SecureRequestData(const details::SecureRequestCreateTag &) {
-	}
-
-	// in toSend: = 0 - must send in container, > 0 - can send without container
-	// in haveSent: = 0 - container with msgIds, > 0 - when was sent
-	int64 msDate = 0;
-
-	mtpRequestId requestId = 0;
-	SecureRequest after;
-	bool needsLayer = false;
-
-};
-
-template <typename Request, typename>
-SecureRequest SecureRequest::Serialize(const Request &request) {
-	const auto requestSize = tl::count_length(request) >> 2;
-	auto serialized = Prepare(requestSize);
-	request.template write<mtpBuffer>(*serialized);
-	return serialized;
-}
-
-} // namespace MTP
-
 using MTPint = tl::int_type;
 
 inline MTPint MTP_int(int32 v) {
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
index ae68422b5..c84a40bbd 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.cpp
@@ -7,6 +7,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/details/mtproto_bound_key_creator.h"
 
+#include "mtproto/details/mtproto_serialized_request.h"
+
 namespace MTP::details {
 
 BoundKeyCreator::BoundKeyCreator(DcKeyRequest request, Delegate delegate)
@@ -54,7 +56,7 @@ bool BoundKeyCreator::readyToBind() const {
 	return _binder.has_value();
 }
 
-SecureRequest BoundKeyCreator::prepareBindRequest(
+SerializedRequest BoundKeyCreator::prepareBindRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId) {
 	Expects(_binder.has_value());
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
index e8a7bf100..a1ca4cb83 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_bound_key_creator.h
@@ -12,6 +12,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace MTP::details {
 
+class SerializedRequest;
+
 class BoundKeyCreator final {
 public:
 	struct Delegate {
@@ -32,7 +34,7 @@ public:
 	void bind(AuthKeyPtr &&persistentKey);
 	void restartBinder();
 	[[nodiscard]] bool readyToBind() const;
-	[[nodiscard]] SecureRequest prepareBindRequest(
+	[[nodiscard]] SerializedRequest prepareBindRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId);
 	[[nodiscard]] DcKeyBindState handleBindResponse(
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
index 736a6f4fa..0f6b0b56c 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/details/mtproto_dc_key_binder.h"
 
+#include "mtproto/details/mtproto_serialized_request.h"
 #include "mtproto/mtp_instance.h"
 #include "base/unixtime.h"
 #include "base/openssl_help.h"
@@ -21,12 +22,12 @@ namespace {
 		const AuthKeyPtr &persistentKey,
 		mtpMsgId realMsgId,
 		const MTPBindAuthKeyInner &data) {
-	auto serialized = SecureRequest::Serialize(data);
+	auto serialized = SerializedRequest::Serialize(data);
 	serialized.setMsgId(realMsgId);
 	serialized.setSeqNo(0);
 	serialized.addPadding(false, true);
 
-	constexpr auto kMsgIdPosition = SecureRequest::kMessageIdPosition;
+	constexpr auto kMsgIdPosition = SerializedRequest::kMessageIdPosition;
 	constexpr auto kMinMessageSize = 5;
 
 	const auto sizeInPrimes = serialized->size();
@@ -77,7 +78,7 @@ DcKeyBinder::DcKeyBinder(AuthKeyPtr &&persistentKey)
 	Expects(_persistentKey != nullptr);
 }
 
-SecureRequest DcKeyBinder::prepareRequest(
+SerializedRequest DcKeyBinder::prepareRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId) {
 	Expects(temporaryKey != nullptr);
@@ -85,7 +86,7 @@ SecureRequest DcKeyBinder::prepareRequest(
 
 	const auto nonce = openssl::RandomValue<uint64>();
 	const auto msgId = base::unixtime::mtproto_msg_id();
-	auto result = SecureRequest::Serialize(MTPauth_BindTempAuthKey(
+	auto result = SerializedRequest::Serialize(MTPauth_BindTempAuthKey(
 		MTP_long(_persistentKey->keyId()),
 		MTP_long(nonce),
 		MTP_int(temporaryKey->expiresAt()),
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
index ba18176e4..882e0f88d 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_binder.h
@@ -16,6 +16,8 @@ class Instance;
 
 namespace MTP::details {
 
+class SerializedRequest;
+
 enum class DcKeyBindState {
 	Success,
 	Failed,
@@ -26,7 +28,7 @@ class DcKeyBinder final {
 public:
 	explicit DcKeyBinder(AuthKeyPtr &&persistentKey);
 
-	[[nodiscard]] SecureRequest prepareRequest(
+	[[nodiscard]] SerializedRequest prepareRequest(
 		const AuthKeyPtr &temporaryKey,
 		uint64 sessionId);
 	[[nodiscard]] DcKeyBindState handleResponse(const mtpBuffer &response);
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h b/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h
index f24361655..61c47665e 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dump_to_text.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/core_types.h"
+#include "mtproto/details/mtproto_serialized_request.h"
 
 namespace MTP::details {
 
diff --git a/Telegram/SourceFiles/mtproto/core_types.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
similarity index 55%
rename from Telegram/SourceFiles/mtproto/core_types.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
index 50e62f95e..032957d40 100644
--- a/Telegram/SourceFiles/mtproto/core_types.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
@@ -5,9 +5,11 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/core_types.h"
+#include "mtproto/details/mtproto_serialized_request.h"
 
-namespace MTP {
+#include "base/openssl_help.h"
+
+namespace MTP::details {
 namespace {
 
 uint32 CountPaddingPrimesCount(uint32 requestSize, bool extended, bool old) {
@@ -27,7 +29,7 @@ uint32 CountPaddingPrimesCount(uint32 requestSize, bool extended, bool old) {
 
 	if (extended) {
 		// Some more random padding.
-		result += ((rand_value<uchar>() & 0x0F) << 2);
+		result += ((openssl::RandomValue<uchar>() & 0x0F) << 2);
 	}
 
 	return result;
@@ -35,67 +37,72 @@ uint32 CountPaddingPrimesCount(uint32 requestSize, bool extended, bool old) {
 
 } // namespace
 
-SecureRequest::SecureRequest(const details::SecureRequestCreateTag &tag)
-: _data(std::make_shared<SecureRequestData>(tag)) {
+SerializedRequest::SerializedRequest(const RequestConstructHider::Tag &tag)
+: _data(std::make_shared<RequestData>(tag)) {
 }
 
-SecureRequest SecureRequest::Prepare(uint32 size, uint32 reserveSize) {
+SerializedRequest SerializedRequest::Prepare(
+		uint32 size,
+		uint32 reserveSize) {
+	Expects(size > 0);
+
 	const auto finalSize = std::max(size, reserveSize);
 
-	auto result = SecureRequest(details::SecureRequestCreateTag{});
+	auto result = SerializedRequest(RequestConstructHider::Tag{});
 	result->reserve(kMessageBodyPosition + finalSize);
 	result->resize(kMessageBodyPosition);
 	result->back() = (size << 2);
-	result->msDate = crl::now(); // > 0 - can send without container
+	result->lastSentTime = crl::now();
 	return result;
 }
 
-SecureRequestData *SecureRequest::operator->() const {
+RequestData *SerializedRequest::operator->() const {
 	Expects(_data != nullptr);
 
 	return _data.get();
 }
 
-SecureRequestData &SecureRequest::operator*() const {
+RequestData &SerializedRequest::operator*() const {
 	Expects(_data != nullptr);
 
 	return *_data;
 }
 
-SecureRequest::operator bool() const {
+SerializedRequest::operator bool() const {
 	return (_data != nullptr);
 }
 
-void SecureRequest::setMsgId(mtpMsgId msgId) {
+void SerializedRequest::setMsgId(mtpMsgId msgId) {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
 	memcpy(_data->data() + kMessageIdPosition, &msgId, sizeof(mtpMsgId));
 }
 
-mtpMsgId SecureRequest::getMsgId() const {
+mtpMsgId SerializedRequest::getMsgId() const {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
 	return *(mtpMsgId*)(_data->constData() + kMessageIdPosition);
 }
 
-void SecureRequest::setSeqNo(uint32 seqNo) {
+void SerializedRequest::setSeqNo(uint32 seqNo) {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
 	(*_data)[kSeqNoPosition] = mtpPrime(seqNo);
 }
 
-uint32 SecureRequest::getSeqNo() const {
+uint32 SerializedRequest::getSeqNo() const {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
 	return uint32((*_data)[kSeqNoPosition]);
 }
 
-void SecureRequest::addPadding(bool extended, bool old) {
+void SerializedRequest::addPadding(bool extended, bool old) {
 	Expects(_data != nullptr);
-
-	if (_data->size() <= kMessageBodyPosition) {
-		return;
-	}
+	Expects(_data->size() > kMessageBodyPosition);
 
 	const auto requestSize = (tl::count_length(*this) >> 2);
 	const auto padding = CountPaddingPrimesCount(requestSize, extended, old);
@@ -103,48 +110,38 @@ void SecureRequest::addPadding(bool extended, bool old) {
 	if (uint32(_data->size()) != fullSize) {
 		_data->resize(fullSize);
 		if (padding > 0) {
-			memset_rand(
-				_data->data() + (fullSize - padding),
-				padding * sizeof(mtpPrime));
+			bytes::set_random(bytes::make_span(*_data).subspan(
+				(fullSize - padding) * sizeof(mtpPrime)));
 		}
 	}
 }
 
-uint32 SecureRequest::messageSize() const {
+uint32 SerializedRequest::messageSize() const {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
-	if (_data->size() <= kMessageBodyPosition) {
-		return 0;
-	}
 	const auto ints = (tl::count_length(*this) >> 2);
 	return kMessageIdInts + kSeqNoInts + kMessageLengthInts + ints;
 }
 
-bool SecureRequest::isSentContainer() const {
+bool SerializedRequest::isSentContainer() const {
 	Expects(_data != nullptr);
 
-	if (_data->size() <= kMessageBodyPosition) {
-		return false;
-	}
-	return (!_data->msDate && !getSeqNo()); // msDate = 0, seqNo = 0
+	return _data->isContainerIdsWrap;
 }
 
-bool SecureRequest::isStateRequest() const {
+bool SerializedRequest::isStateRequest() const {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
-	if (_data->size() <= kMessageBodyPosition) {
-		return false;
-	}
 	const auto type = mtpTypeId((*_data)[kMessageBodyPosition]);
 	return (type == mtpc_msgs_state_req);
 }
 
-bool SecureRequest::needAck() const {
+bool SerializedRequest::needAck() const {
 	Expects(_data != nullptr);
+	Expects(_data->size() > kMessageBodyPosition);
 
-	if (_data->size() <= kMessageBodyPosition) {
-		return false;
-	}
 	const auto type = mtpTypeId((*_data)[kMessageBodyPosition]);
 	switch (type) {
 	case mtpc_msg_container:
@@ -160,16 +157,14 @@ bool SecureRequest::needAck() const {
 	return true;
 }
 
-size_t SecureRequest::sizeInBytes() const {
-	return (_data && _data->size() > kMessageBodyPosition)
-		? (*_data)[kMessageLengthPosition]
-		: 0;
+size_t SerializedRequest::sizeInBytes() const {
+	Expects(!_data || _data->size() > kMessageBodyPosition);
+	return _data ? (*_data)[kMessageLengthPosition] : 0;
 }
 
-const void *SecureRequest::dataInBytes() const {
-	return (_data && _data->size() > kMessageBodyPosition)
-		? (_data->constData() + kMessageBodyPosition)
-		: nullptr;
+const void *SerializedRequest::dataInBytes() const {
+	Expects(!_data || _data->size() > kMessageBodyPosition);
+	return _data ? (_data->constData() + kMessageBodyPosition) : nullptr;
 }
 
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
new file mode 100644
index 000000000..08e13380e
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
@@ -0,0 +1,109 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "mtproto/core_types.h"
+
+#include <crl/crl_time.h>
+
+namespace MTP::details {
+
+class RequestData;
+class SerializedRequest;
+
+class RequestConstructHider {
+	struct Tag {};
+	friend class RequestData;
+	friend class SerializedRequest;
+};
+
+class SerializedRequest {
+public:
+	SerializedRequest() = default;
+
+	static constexpr auto kSaltInts = 2;
+	static constexpr auto kSessionIdInts = 2;
+	static constexpr auto kMessageIdPosition = kSaltInts + kSessionIdInts;
+	static constexpr auto kMessageIdInts = 2;
+	static constexpr auto kSeqNoPosition = kMessageIdPosition
+		+ kMessageIdInts;
+	static constexpr auto kSeqNoInts = 1;
+	static constexpr auto kMessageLengthPosition = kSeqNoPosition
+		+ kSeqNoInts;
+	static constexpr auto kMessageLengthInts = 1;
+	static constexpr auto kMessageBodyPosition = kMessageLengthPosition
+		+ kMessageLengthInts;
+
+	static SerializedRequest Prepare(uint32 size, uint32 reserveSize = 0);
+
+	template <
+		typename Request,
+		typename = std::enable_if_t<tl::is_boxed_v<Request>>>
+	static SerializedRequest Serialize(const Request &request);
+
+	// For template MTP requests and MTPBoxed instantiation.
+	template <typename Accumulator>
+	void write(Accumulator &to) const {
+		if (const auto size = sizeInBytes()) {
+			tl::Writer<Accumulator>::PutBytes(to, dataInBytes(), size);
+		}
+	}
+
+	RequestData *operator->() const;
+	RequestData &operator*() const;
+	explicit operator bool() const;
+
+	void setMsgId(mtpMsgId msgId);
+	[[nodiscard]] mtpMsgId getMsgId() const;
+
+	void setSeqNo(uint32 seqNo);
+	[[nodiscard]] uint32 getSeqNo() const;
+
+	void addPadding(bool extended, bool old);
+	[[nodiscard]] uint32 messageSize() const;
+
+	// "request-like" wrap for msgIds vector
+	[[nodiscard]] bool isSentContainer() const;
+	[[nodiscard]] bool isStateRequest() const;
+	[[nodiscard]] bool needAck() const;
+
+	using ResponseType = void; // don't know real response type =(
+
+private:
+	explicit SerializedRequest(const RequestConstructHider::Tag &);
+
+	[[nodiscard]] size_t sizeInBytes() const;
+	[[nodiscard]] const void *dataInBytes() const;
+
+	std::shared_ptr<RequestData> _data;
+
+};
+
+class RequestData : public mtpBuffer {
+public:
+	explicit RequestData(const RequestConstructHider::Tag &) {
+	}
+
+	SerializedRequest after;
+	crl::time lastSentTime = 0;
+	mtpRequestId requestId = 0;
+	bool needsLayer = false;
+	bool forceSendInContainer = false;
+	bool isContainerIdsWrap = false;
+
+};
+
+template <typename Request, typename>
+SerializedRequest SerializedRequest::Serialize(const Request &request) {
+	const auto requestSize = tl::count_length(request) >> 2;
+	auto serialized = Prepare(requestSize);
+	request.template write<mtpBuffer>(*serialized);
+	return serialized;
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 20fa3e1a5..888728b9d 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -36,6 +36,7 @@ constexpr auto kConfigBecomesOldForBlockedIn = 8 * crl::time(1000);
 constexpr auto kCheckKeyEach = 60 * crl::time(1000);
 
 using namespace internal;
+using namespace details;
 
 std::atomic<int> GlobalAtomicRequestId = 0;
 
@@ -111,7 +112,7 @@ public:
 
 	void sendRequest(
 		mtpRequestId requestId,
-		SecureRequest &&request,
+		SerializedRequest &&request,
 		RPCResponseHandler &&callbacks,
 		ShiftedDcId shiftedDcId,
 		crl::time msCanWait,
@@ -121,9 +122,9 @@ public:
 	void unregisterRequest(mtpRequestId requestId);
 	void storeRequest(
 		mtpRequestId requestId,
-		const SecureRequest &request,
+		const SerializedRequest &request,
 		RPCResponseHandler &&callbacks);
-	SecureRequest getRequest(mtpRequestId requestId);
+	SerializedRequest getRequest(mtpRequestId requestId);
 	void clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids);
 	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
 	bool hasCallbacks(mtpRequestId requestId);
@@ -238,7 +239,7 @@ private:
 	std::map<mtpRequestId, RPCResponseHandler> _parserMap;
 	QMutex _parserMapLock;
 
-	std::map<mtpRequestId, SecureRequest> _requestMap;
+	std::map<mtpRequestId, SerializedRequest> _requestMap;
 	QReadWriteLock _requestMapLock;
 
 	std::deque<std::pair<mtpRequestId, crl::time>> _delayedRequests;
@@ -911,7 +912,7 @@ void Instance::Private::checkDelayedRequests() {
 			continue;
 		}
 
-		auto request = SecureRequest();
+		auto request = SerializedRequest();
 		{
 			QReadLocker locker(&_requestMapLock);
 			auto it = _requestMap.find(requestId);
@@ -932,7 +933,7 @@ void Instance::Private::checkDelayedRequests() {
 
 void Instance::Private::sendRequest(
 		mtpRequestId requestId,
-		SecureRequest &&request,
+		SerializedRequest &&request,
 		RPCResponseHandler &&callbacks,
 		ShiftedDcId shiftedDcId,
 		crl::time msCanWait,
@@ -951,7 +952,7 @@ void Instance::Private::sendRequest(
 	if (afterRequestId) {
 		request->after = getRequest(afterRequestId);
 	}
-	request->msDate = crl::now(); // > 0 - can send without container
+	request->lastSentTime = crl::now();
 	request->needsLayer = needsLayer;
 
 	session->sendPrepared(request, msCanWait);
@@ -980,7 +981,7 @@ void Instance::Private::unregisterRequest(mtpRequestId requestId) {
 
 void Instance::Private::storeRequest(
 		mtpRequestId requestId,
-		const SecureRequest &request,
+		const SerializedRequest &request,
 		RPCResponseHandler &&callbacks) {
 	if (callbacks.onDone || callbacks.onFail) {
 		QMutexLocker locker(&_parserMapLock);
@@ -992,8 +993,8 @@ void Instance::Private::storeRequest(
 	}
 }
 
-SecureRequest Instance::Private::getRequest(mtpRequestId requestId) {
-	auto result = SecureRequest();
+SerializedRequest Instance::Private::getRequest(mtpRequestId requestId) {
+	auto result = SerializedRequest();
 	{
 		QReadLocker locker(&_requestMapLock);
 		auto it = _requestMap.find(requestId);
@@ -1319,7 +1320,7 @@ bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &e
 			newdcWithShift = ShiftDcId(newdcWithShift, GetDcIdShift(dcWithShift));
 		}
 
-		auto request = SecureRequest();
+		auto request = SerializedRequest();
 		{
 			QReadLocker locker(&_requestMapLock);
 			auto it = _requestMap.find(requestId);
@@ -1391,7 +1392,7 @@ bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &e
 		if (badGuestDc) _badGuestDcRequests.insert(requestId);
 		return true;
 	} else if (err == qstr("CONNECTION_NOT_INITED") || err == qstr("CONNECTION_LAYER_INVALID")) {
-		SecureRequest request;
+		SerializedRequest request;
 		{
 			QReadLocker locker(&_requestMapLock);
 			auto it = _requestMap.find(requestId);
@@ -1416,7 +1417,7 @@ bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &e
 	} else if (err == qstr("CONNECTION_LANG_CODE_INVALID")) {
 		Lang::CurrentCloudManager().resetToDefault();
 	} else if (err == qstr("MSG_WAIT_FAILED")) {
-		SecureRequest request;
+		SerializedRequest request;
 		{
 			QReadLocker locker(&_requestMapLock);
 			auto it = _requestMap.find(requestId);
@@ -1435,7 +1436,7 @@ bool Instance::Private::onErrorDefault(mtpRequestId requestId, const RPCError &e
 			if (const auto afterDcId = queryRequestByDc(request->after->requestId)) {
 				dcWithShift = *shiftedDcId;
 				if (*shiftedDcId != *afterDcId) {
-					request->after = SecureRequest();
+					request->after = SerializedRequest();
 				}
 			} else {
 				LOG(("MTP Error: could not find dependent request %1 by dc").arg(request->after->requestId));
@@ -1852,7 +1853,7 @@ void Instance::keyDestroyedOnServer(ShiftedDcId shiftedDcId, uint64 keyId) {
 
 void Instance::sendRequest(
 		mtpRequestId requestId,
-		SecureRequest &&request,
+		SerializedRequest &&request,
 		RPCResponseHandler &&callbacks,
 		ShiftedDcId shiftedDcId,
 		crl::time msCanWait,
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index a59a96a9b..17e2f5889 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -8,6 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "mtproto/mtproto_rpc_sender.h"
+#include "mtproto/details/mtproto_serialized_request.h"
 
 namespace MTP {
 namespace internal {
@@ -139,7 +140,7 @@ public:
 		const auto requestId = internal::GetNextRequestId();
 		sendSerialized(
 			requestId,
-			SecureRequest::Serialize(request),
+			details::SerializedRequest::Serialize(request),
 			std::move(callbacks),
 			shiftedDcId,
 			msCanWait,
@@ -170,7 +171,7 @@ public:
 		const auto requestId = internal::GetNextRequestId();
 		sendRequest(
 			requestId,
-			SecureRequest::Serialize(request),
+			details::SerializedRequest::Serialize(request),
 			{},
 			shiftedDcId,
 			0,
@@ -181,7 +182,7 @@ public:
 
 	void sendSerialized(
 			mtpRequestId requestId,
-			SecureRequest &&request,
+			details::SerializedRequest &&request,
 			RPCResponseHandler &&callbacks,
 			ShiftedDcId shiftedDcId,
 			crl::time msCanWait,
@@ -209,7 +210,7 @@ signals:
 private:
 	void sendRequest(
 		mtpRequestId requestId,
-		SecureRequest &&request,
+		details::SerializedRequest &&request,
 		RPCResponseHandler &&callbacks,
 		ShiftedDcId shiftedDcId,
 		crl::time msCanWait,
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index ba2ce7fd4..66cf7f31e 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -94,12 +94,6 @@ void SessionData::queueSendAnything(crl::time msCanWait) {
 	});
 }
 
-void SessionData::queueSendMsgsStateInfo(quint64 msgId, QByteArray data) {
-	withSession([=](not_null<Session*> session) {
-		session->sendMsgsStateInfo(msgId, data);
-	});
-}
-
 bool SessionData::connectionInited() const {
 	QMutexLocker lock(&_ownerMutex);
 	return _owner ? _owner->connectionInited() : false;
@@ -300,18 +294,6 @@ void Session::needToResumeAndSend() {
 	}
 }
 
-void Session::sendMsgsStateInfo(quint64 msgId, QByteArray data) {
-	auto info = bytes::vector();
-	if (!data.isEmpty()) {
-		info.resize(data.size());
-		bytes::copy(info, bytes::make_span(data));
-	}
-	_instance->sendProtocolMessage(
-		_shiftedDcId,
-		MTPMsgsStateInfo(
-			MTP_msgs_state_info(MTP_long(msgId), MTP_bytes(data))));
-}
-
 void Session::connectionStateChange(int newState) {
 	_instance->onStateChange(_shiftedDcId, newState);
 }
@@ -356,17 +338,14 @@ int32 Session::requestState(mtpRequestId requestId) const {
 	}
 	if (!connected) {
 		return result;
-	}
-	if (!requestId) return MTP::RequestSent;
-
-	QWriteLocker locker(_data->toSendMutex());
-	const auto &toSend = _data->toSendMap();
-	const auto i = toSend.constFind(requestId);
-	if (i != toSend.cend()) {
-		return MTP::RequestSending;
-	} else {
+	} else if (!requestId) {
 		return MTP::RequestSent;
 	}
+
+	QWriteLocker locker(_data->toSendMutex());
+	return _data->toSendMap().contains(requestId)
+		? MTP::RequestSending
+		: MTP::RequestSent;
 }
 
 int32 Session::getState() const {
@@ -397,13 +376,13 @@ QString Session::transport() const {
 }
 
 void Session::sendPrepared(
-		const SecureRequest &request,
+		const details::SerializedRequest &request,
 		crl::time msCanWait) {
 	DEBUG_LOG(("MTP Info: adding request to toSendMap, msCanWait %1"
 		).arg(msCanWait));
 	{
 		QWriteLocker locker(_data->toSendMutex());
-		_data->toSendMap().insert(request->requestId, request);
+		_data->toSendMap().emplace(request->requestId, request);
 		*(mtpMsgId*)(request->data() + 4) = 0;
 		*(request->data() + 6) = 0;
 	}
@@ -510,35 +489,27 @@ void Session::tryToReceive() {
 		return;
 	}
 	while (true) {
-		auto requestId = mtpRequestId(0);
-		auto isUpdate = false;
-		auto message = SerializedMessage();
-		{
-			QWriteLocker locker(_data->haveReceivedMutex());
-			auto &responses = _data->haveReceivedResponses();
-			auto response = responses.begin();
-			if (response == responses.cend()) {
-				auto &updates = _data->haveReceivedUpdates();
-				auto update = updates.begin();
-				if (update == updates.cend()) {
-					return;
-				} else {
-					message = std::move(*update);
-					isUpdate = true;
-					updates.pop_front();
-				}
-			} else {
-				requestId = response.key();
-				message = std::move(response.value());
-				responses.erase(response);
-			}
+		auto lock = QWriteLocker(_data->haveReceivedMutex());
+		const auto responses = base::take(_data->haveReceivedResponses());
+		const auto updates = base::take(_data->haveReceivedUpdates());
+		lock.unlock();
+		if (responses.empty() && updates.empty()) {
+			break;
 		}
-		if (isUpdate) {
-			if (_shiftedDcId == BareDcId(_shiftedDcId)) { // call globalCallback only in main session
-				_instance->globalCallback(message.constData(), message.constData() + message.size());
+		for (const auto &[requestId, response] : responses) {
+			_instance->execCallback(
+				requestId,
+				response.constData(),
+				response.constData() + response.size());
+		}
+
+		// Call globalCallback only in main session.
+		if (_shiftedDcId == BareDcId(_shiftedDcId)) {
+			for (const auto &update : updates) {
+				_instance->globalCallback(
+					update.constData(),
+					update.constData() + update.size());
 			}
-		} else {
-			_instance->execCallback(requestId, message.constData(), message.constData() + message.size());
 		}
 	}
 }
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 896dafe4b..ce4ef83a3 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 #include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/mtproto_proxy_data.h"
+#include "mtproto/details/mtproto_serialized_request.h"
 
 #include <QtCore/QTimer>
 
@@ -27,18 +28,6 @@ class Connection;
 enum class TemporaryKeyType;
 enum class CreatingKeyType;
 
-using PreRequestMap = QMap<mtpRequestId, SecureRequest>;
-using RequestMap = QMap<mtpMsgId, SecureRequest>;
-using SerializedMessage = mtpBuffer;
-
-inline bool ResponseNeedsAck(const SerializedMessage &response) {
-	if (response.size() < 8) {
-		return false;
-	}
-	auto seqNo = *(uint32*)(response.constData() + 6);
-	return (seqNo & 0x01) ? true : false;
-}
-
 struct ConnectionOptions {
 	ConnectionOptions() = default;
 	ConnectionOptions(
@@ -80,38 +69,26 @@ public:
 		return _options;
 	}
 
-	not_null<QReadWriteLock*> toSendMutex() const {
+	not_null<QReadWriteLock*> toSendMutex() {
 		return &_toSendLock;
 	}
-	not_null<QReadWriteLock*> haveSentMutex() const {
+	not_null<QReadWriteLock*> haveSentMutex() {
 		return &_haveSentLock;
 	}
-	not_null<QReadWriteLock*> haveReceivedMutex() const {
+	not_null<QReadWriteLock*> haveReceivedMutex() {
 		return &_haveReceivedLock;
 	}
 
-	PreRequestMap &toSendMap() {
+	base::flat_map<mtpRequestId, details::SerializedRequest> &toSendMap() {
 		return _toSend;
 	}
-	const PreRequestMap &toSendMap() const {
-		return _toSend;
-	}
-	RequestMap &haveSentMap() {
+	base::flat_map<mtpMsgId, details::SerializedRequest> &haveSentMap() {
 		return _haveSent;
 	}
-	const RequestMap &haveSentMap() const {
-		return _haveSent;
-	}
-	QMap<mtpRequestId, SerializedMessage> &haveReceivedResponses() {
+	base::flat_map<mtpRequestId, mtpBuffer> &haveReceivedResponses() {
 		return _receivedResponses;
 	}
-	const QMap<mtpRequestId, SerializedMessage> &haveReceivedResponses() const {
-		return _receivedResponses;
-	}
-	QList<SerializedMessage> &haveReceivedUpdates() {
-		return _receivedUpdates;
-	}
-	const QList<SerializedMessage> &haveReceivedUpdates() const {
+	std::vector<mtpBuffer> &haveReceivedUpdates() {
 		return _receivedUpdates;
 	}
 
@@ -126,7 +103,6 @@ public:
 	void queueConnectionStateChange(int newState);
 	void queueResetDone();
 	void queueSendAnything(crl::time msCanWait = 0);
-	void queueSendMsgsStateInfo(quint64 msgId, QByteArray data);
 
 	[[nodiscard]] bool connectionInited() const;
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
@@ -148,18 +124,17 @@ private:
 	mutable QMutex _ownerMutex;
 
 	ConnectionOptions _options;
-
-	PreRequestMap _toSend; // map of request_id -> request, that is waiting to be sent
-	RequestMap _haveSent; // map of msg_id -> request, that was sent, msDate = 0 for msgs_state_req (no resend / state req), msDate = 0, seqNo = 0 for containers
-
-	QMap<mtpRequestId, SerializedMessage> _receivedResponses; // map of request_id -> response that should be processed in the main thread
-	QList<SerializedMessage> _receivedUpdates; // list of updates that should be processed in the main thread
-
-	// mutexes
 	mutable QReadWriteLock _optionsLock;
-	mutable QReadWriteLock _toSendLock;
-	mutable QReadWriteLock _haveSentLock;
-	mutable QReadWriteLock _haveReceivedLock;
+
+	base::flat_map<mtpRequestId, details::SerializedRequest> _toSend; // map of request_id -> request, that is waiting to be sent
+	QReadWriteLock _toSendLock;
+
+	base::flat_map<mtpMsgId, details::SerializedRequest> _haveSent; // map of msg_id -> request, that was sent
+	QReadWriteLock _haveSentLock;
+
+	base::flat_map<mtpRequestId, mtpBuffer> _receivedResponses; // map of request_id -> response that should be processed in the main thread
+	std::vector<mtpBuffer> _receivedUpdates; // list of updates that should be processed in the main thread
+	QReadWriteLock _haveReceivedLock;
 
 };
 
@@ -189,7 +164,9 @@ public:
 	[[nodiscard]] AuthKeyPtr getPersistentKey() const;
 	[[nodiscard]] AuthKeyPtr getTemporaryKey(TemporaryKeyType type) const;
 	[[nodiscard]] bool connectionInited() const;
-	void sendPrepared(const SecureRequest &request, crl::time msCanWait = 0);
+	void sendPrepared(
+		const details::SerializedRequest &request,
+		crl::time msCanWait = 0);
 
 	// Connection thread.
 	[[nodiscard]] CreatingKeyType acquireKeyCreation(TemporaryKeyType type);
@@ -212,7 +189,6 @@ public:
 	void connectionStateChange(int newState);
 	void resetDone();
 	void sendAnything(crl::time msCanWait = 0);
-	void sendMsgsStateInfo(quint64 msgId, QByteArray data);
 
 signals:
 	void authKeyChanged();
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index 4b01766a2..f95b4310d 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -44,6 +44,8 @@
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.h',
       '<(src_loc)/mtproto/details/mtproto_received_ids_manager.cpp',
       '<(src_loc)/mtproto/details/mtproto_received_ids_manager.h',
+      '<(src_loc)/mtproto/details/mtproto_serialized_request.cpp',
+      '<(src_loc)/mtproto/details/mtproto_serialized_request.h',
       '<(src_loc)/mtproto/mtproto_abstract_socket.cpp',
       '<(src_loc)/mtproto/mtproto_abstract_socket.h',
       '<(src_loc)/mtproto/mtproto_auth_key.cpp',
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index e7ccceed3..0bd944970 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -547,7 +547,6 @@
 <(src_loc)/mtproto/connection_resolving.h
 <(src_loc)/mtproto/connection_tcp.cpp
 <(src_loc)/mtproto/connection_tcp.h
-<(src_loc)/mtproto/core_types.cpp
 <(src_loc)/mtproto/core_types.h
 <(src_loc)/mtproto/dcenter.cpp
 <(src_loc)/mtproto/dcenter.h
diff --git a/Telegram/lib_tl b/Telegram/lib_tl
index 2bf101114..13918d5b5 160000
--- a/Telegram/lib_tl
+++ b/Telegram/lib_tl
@@ -1 +1 @@
-Subproject commit 2bf101114f0a54c868a2703a9a80c06c0f2d2c41
+Subproject commit 13918d5b5c4611ef1563a13ac1daf4d2c77c5f49

From 9e37088f43cea6ab8ddefb96cab80fb7f50689be Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Sat, 23 Nov 2019 19:34:15 +0300
Subject: [PATCH 48/91] Closed alpha version 1.9.1.3.

---
 Telegram/Resources/uwp/AppX/AppxManifest.xml | 2 +-
 Telegram/Resources/winrc/Telegram.rc         | 8 ++++----
 Telegram/Resources/winrc/Updater.rc          | 8 ++++----
 Telegram/SourceFiles/core/version.h          | 2 +-
 Telegram/build/version                       | 2 +-
 5 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Telegram/Resources/uwp/AppX/AppxManifest.xml b/Telegram/Resources/uwp/AppX/AppxManifest.xml
index 7dd60cca9..ffade44d8 100644
--- a/Telegram/Resources/uwp/AppX/AppxManifest.xml
+++ b/Telegram/Resources/uwp/AppX/AppxManifest.xml
@@ -9,7 +9,7 @@
   <Identity Name="TelegramMessengerLLP.TelegramDesktop"
     ProcessorArchitecture="ARCHITECTURE"
     Publisher="CN=536BC709-8EE1-4478-AF22-F0F0F26FF64A"
-    Version="1.9.1.2" />
+    Version="1.9.1.3" />
   <Properties>
     <DisplayName>Telegram Desktop</DisplayName>
     <PublisherDisplayName>Telegram FZ-LLC</PublisherDisplayName>
diff --git a/Telegram/Resources/winrc/Telegram.rc b/Telegram/Resources/winrc/Telegram.rc
index 47b76bfca..825b6608b 100644
--- a/Telegram/Resources/winrc/Telegram.rc
+++ b/Telegram/Resources/winrc/Telegram.rc
@@ -33,8 +33,8 @@ IDI_ICON1               ICON                    "..\\art\\icon256.ico"
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,2
- PRODUCTVERSION 1,9,1,2
+ FILEVERSION 1,9,1,3
+ PRODUCTVERSION 1,9,1,3
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -51,10 +51,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop"
-            VALUE "FileVersion", "1.9.1.2"
+            VALUE "FileVersion", "1.9.1.3"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.2"
+            VALUE "ProductVersion", "1.9.1.3"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/Resources/winrc/Updater.rc b/Telegram/Resources/winrc/Updater.rc
index 2a4243e08..d76eb4ee2 100644
--- a/Telegram/Resources/winrc/Updater.rc
+++ b/Telegram/Resources/winrc/Updater.rc
@@ -24,8 +24,8 @@ LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,2
- PRODUCTVERSION 1,9,1,2
+ FILEVERSION 1,9,1,3
+ PRODUCTVERSION 1,9,1,3
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -42,10 +42,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop Updater"
-            VALUE "FileVersion", "1.9.1.2"
+            VALUE "FileVersion", "1.9.1.3"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.2"
+            VALUE "ProductVersion", "1.9.1.3"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/SourceFiles/core/version.h b/Telegram/SourceFiles/core/version.h
index e7ca94112..958226fd4 100644
--- a/Telegram/SourceFiles/core/version.h
+++ b/Telegram/SourceFiles/core/version.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001002ULL)
+#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001003ULL)
 
 #ifdef TDESKTOP_OFFICIAL_TARGET
 #define TDESKTOP_ALPHA_VERSION TDESKTOP_REQUESTED_ALPHA_VERSION
diff --git a/Telegram/build/version b/Telegram/build/version
index 97b2f3729..e54030ce1 100644
--- a/Telegram/build/version
+++ b/Telegram/build/version
@@ -3,4 +3,4 @@ AppVersionStrMajor 1.9
 AppVersionStrSmall 1.9.1
 AppVersionStr      1.9.1
 BetaChannel        0
-AlphaVersion       1009001002
+AlphaVersion       1009001003

From 9d0332be0a49c8a5d4642bf0d158fddbeb577bba Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Sat, 23 Nov 2019 19:40:06 +0300
Subject: [PATCH 49/91] Closed alpha version 1.9.1.3: Update lib_spellcheck.

---
 Telegram/lib_spellcheck | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/lib_spellcheck b/Telegram/lib_spellcheck
index b815a8385..dd47a0c30 160000
--- a/Telegram/lib_spellcheck
+++ b/Telegram/lib_spellcheck
@@ -1 +1 @@
-Subproject commit b815a83854939cac6aa37430be54193b2b0e50c6
+Subproject commit dd47a0c3080c5d5cfb431f87f17bca9239151ca7

From 8979525dc0ab8fb96fbc05687b98084f3e4d17c4 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 25 Nov 2019 09:57:55 +0300
Subject: [PATCH 50/91] Closed alpha version 1.9.1.4.

---
 Telegram/Resources/uwp/AppX/AppxManifest.xml | 2 +-
 Telegram/Resources/winrc/Telegram.rc         | 8 ++++----
 Telegram/Resources/winrc/Updater.rc          | 8 ++++----
 Telegram/SourceFiles/core/version.h          | 2 +-
 Telegram/build/version                       | 2 +-
 Telegram/lib_spellcheck                      | 2 +-
 6 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/Telegram/Resources/uwp/AppX/AppxManifest.xml b/Telegram/Resources/uwp/AppX/AppxManifest.xml
index ffade44d8..044d61af4 100644
--- a/Telegram/Resources/uwp/AppX/AppxManifest.xml
+++ b/Telegram/Resources/uwp/AppX/AppxManifest.xml
@@ -9,7 +9,7 @@
   <Identity Name="TelegramMessengerLLP.TelegramDesktop"
     ProcessorArchitecture="ARCHITECTURE"
     Publisher="CN=536BC709-8EE1-4478-AF22-F0F0F26FF64A"
-    Version="1.9.1.3" />
+    Version="1.9.1.4" />
   <Properties>
     <DisplayName>Telegram Desktop</DisplayName>
     <PublisherDisplayName>Telegram FZ-LLC</PublisherDisplayName>
diff --git a/Telegram/Resources/winrc/Telegram.rc b/Telegram/Resources/winrc/Telegram.rc
index 825b6608b..9a17a3f2d 100644
--- a/Telegram/Resources/winrc/Telegram.rc
+++ b/Telegram/Resources/winrc/Telegram.rc
@@ -33,8 +33,8 @@ IDI_ICON1               ICON                    "..\\art\\icon256.ico"
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,3
- PRODUCTVERSION 1,9,1,3
+ FILEVERSION 1,9,1,4
+ PRODUCTVERSION 1,9,1,4
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -51,10 +51,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop"
-            VALUE "FileVersion", "1.9.1.3"
+            VALUE "FileVersion", "1.9.1.4"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.3"
+            VALUE "ProductVersion", "1.9.1.4"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/Resources/winrc/Updater.rc b/Telegram/Resources/winrc/Updater.rc
index d76eb4ee2..b99e85983 100644
--- a/Telegram/Resources/winrc/Updater.rc
+++ b/Telegram/Resources/winrc/Updater.rc
@@ -24,8 +24,8 @@ LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,3
- PRODUCTVERSION 1,9,1,3
+ FILEVERSION 1,9,1,4
+ PRODUCTVERSION 1,9,1,4
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -42,10 +42,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop Updater"
-            VALUE "FileVersion", "1.9.1.3"
+            VALUE "FileVersion", "1.9.1.4"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.3"
+            VALUE "ProductVersion", "1.9.1.4"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/SourceFiles/core/version.h b/Telegram/SourceFiles/core/version.h
index 958226fd4..f643ad225 100644
--- a/Telegram/SourceFiles/core/version.h
+++ b/Telegram/SourceFiles/core/version.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001003ULL)
+#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001004ULL)
 
 #ifdef TDESKTOP_OFFICIAL_TARGET
 #define TDESKTOP_ALPHA_VERSION TDESKTOP_REQUESTED_ALPHA_VERSION
diff --git a/Telegram/build/version b/Telegram/build/version
index e54030ce1..f27ed1fce 100644
--- a/Telegram/build/version
+++ b/Telegram/build/version
@@ -3,4 +3,4 @@ AppVersionStrMajor 1.9
 AppVersionStrSmall 1.9.1
 AppVersionStr      1.9.1
 BetaChannel        0
-AlphaVersion       1009001003
+AlphaVersion       1009001004
diff --git a/Telegram/lib_spellcheck b/Telegram/lib_spellcheck
index dd47a0c30..47b2f293c 160000
--- a/Telegram/lib_spellcheck
+++ b/Telegram/lib_spellcheck
@@ -1 +1 @@
-Subproject commit dd47a0c3080c5d5cfb431f87f17bca9239151ca7
+Subproject commit 47b2f293c3b63ccbe871ab6d50edd8d4b8411ecc

From 95ba12e3cba402585fd560650760c3a9efdb3cbe Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 7 Nov 2019 13:24:13 +0300
Subject: [PATCH 51/91] Update API scheme to layer 107.

---
 Telegram/Resources/tl/api.tl                     | 15 ++++++++++++++-
 Telegram/SourceFiles/export/export_api_wrap.cpp  |  4 ++++
 Telegram/SourceFiles/ui/image/image_location.cpp |  6 ++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/Telegram/Resources/tl/api.tl b/Telegram/Resources/tl/api.tl
index 5baf29966..823e996c2 100644
--- a/Telegram/Resources/tl/api.tl
+++ b/Telegram/Resources/tl/api.tl
@@ -89,6 +89,7 @@ inputDocumentFileLocation#bad07584 id:long access_hash:long file_reference:bytes
 inputSecureFileLocation#cbc7ee28 id:long access_hash:long = InputFileLocation;
 inputTakeoutFileLocation#29be5899 = InputFileLocation;
 inputPhotoFileLocation#40181ffe id:long access_hash:long file_reference:bytes thumb_size:string = InputFileLocation;
+inputPhotoLegacyFileLocation#d83466f3 id:long access_hash:long file_reference:bytes volume_id:long local_id:int secret:long = InputFileLocation;
 inputPeerPhotoFileLocation#27d69997 flags:# big:flags.0?true peer:InputPeer volume_id:long local_id:int = InputFileLocation;
 inputStickerSetThumb#dbaeae9 stickerset:InputStickerSet volume_id:long local_id:int = InputFileLocation;
 
@@ -347,6 +348,8 @@ updatePeerLocated#b4afcfb0 peers:Vector<PeerLocated> = Update;
 updateNewScheduledMessage#39a51dfb message:Message = Update;
 updateDeleteScheduledMessages#90866cee peer:Peer messages:Vector<int> = Update;
 updateTheme#8216fba3 theme:Theme = Update;
+updateGeoLiveViewed#871fb939 peer:Peer msg_id:int = Update;
+updateLoginToken#564fe691 = Update;
 
 updates.state#a56c2a3e pts:int qts:int date:int seq:int unread_count:int = updates.State;
 
@@ -1082,6 +1085,12 @@ wallet.liteResponse#764386d7 response:bytes = wallet.LiteResponse;
 
 wallet.secretSalt#dd484d64 salt:bytes = wallet.KeySecretSalt;
 
+auth.loginToken#629f1980 expires:int token:bytes = auth.LoginToken;
+auth.loginTokenMigrateTo#68e9916 dc_id:int token:bytes = auth.LoginToken;
+auth.loginTokenSuccess#390d5c5e authorization:auth.Authorization = auth.LoginToken;
+
+auth.loginTokenInfo#5203303a dc_id:int auth_key_id:long device_model:string platform:string system_version:string api_id:int app_name:string app_version:string ip:string region:string = auth.LoginTokenInfo;
+
 ---functions---
 
 invokeAfterMsg#cb9f372d {X:Type} msg_id:long query:!X = X;
@@ -1107,6 +1116,10 @@ auth.recoverPassword#4ea56e92 code:string = auth.Authorization;
 auth.resendCode#3ef1a9bf phone_number:string phone_code_hash:string = auth.SentCode;
 auth.cancelCode#1f040578 phone_number:string phone_code_hash:string = Bool;
 auth.dropTempAuthKeys#8e48a188 except_auth_keys:Vector<long> = Bool;
+auth.exportLoginToken#b1b41517 api_id:int api_hash:string except_ids:Vector<int> = auth.LoginToken;
+auth.importLoginToken#95ac5ce4 token:bytes = auth.LoginToken;
+auth.acceptLoginToken#42e731b9 token:bytes = Updates;
+auth.checkLoginToken#7d4fd4b0 token:bytes = auth.LoginTokenInfo;
 
 account.registerDevice#68976c6f flags:# no_muted:flags.0?true token_type:int token:string app_sandbox:Bool secret:bytes other_uids:Vector<int> = Bool;
 account.unregisterDevice#3076c4bf token_type:int token:string other_uids:Vector<int> = Bool;
@@ -1422,4 +1435,4 @@ folders.deleteFolder#1c295881 folder_id:int = Updates;
 wallet.sendLiteRequest#e2c9d33e body:bytes = wallet.LiteResponse;
 wallet.getKeySecretSalt#b57f346 revoke:Bool = wallet.KeySecretSalt;
 
-// LAYER 106
+// LAYER 107
diff --git a/Telegram/SourceFiles/export/export_api_wrap.cpp b/Telegram/SourceFiles/export/export_api_wrap.cpp
index 8a6b29811..c47c61379 100644
--- a/Telegram/SourceFiles/export/export_api_wrap.cpp
+++ b/Telegram/SourceFiles/export/export_api_wrap.cpp
@@ -84,6 +84,10 @@ LocationKey ComputeLocationKey(const Data::FileLocation &value) {
 		result.type |= (8ULL << 24);
 		result.type |= (uint64(uint32(data.vlocal_id().v)) << 32);
 		result.id = data.vvolume_id().v;
+	}, [&](const MTPDinputPhotoLegacyFileLocation &data) {
+		result.type |= (9ULL << 24);
+		result.type |= (uint64(uint32(data.vlocal_id().v)) << 32);
+		result.id = data.vvolume_id().v;
 	});
 	return result;
 }
diff --git a/Telegram/SourceFiles/ui/image/image_location.cpp b/Telegram/SourceFiles/ui/image/image_location.cpp
index 573e4678f..ccd7ac2bb 100644
--- a/Telegram/SourceFiles/ui/image/image_location.cpp
+++ b/Telegram/SourceFiles/ui/image/image_location.cpp
@@ -116,6 +116,12 @@ StorageFileLocation::StorageFileLocation(
 		_sizeLetter = data.vthumb_size().v.isEmpty()
 			? char(0)
 			: data.vthumb_size().v[0];
+	}, [&](const MTPDinputPhotoLegacyFileLocation &data) {
+		_type = Type::Legacy;
+		_volumeId = data.vvolume_id().v;
+		_localId = data.vlocal_id().v;
+		_accessHash = data.vsecret().v;
+		_fileReference = data.vfile_reference().v;
 	}, [&](const MTPDinputPeerPhotoFileLocation &data) {
 		_type = Type::PeerPhoto;
 		const auto fillPeer = base::overload([&](

From d5718f96b8c7011dc63910832eaecc838d35b1d0 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 22 Nov 2019 12:40:52 +0300
Subject: [PATCH 52/91] First working auth by QR code.

---
 .gitmodules                                   |   6 +
 Telegram/Resources/langs/lang.strings         |   4 +
 Telegram/SourceFiles/intro/intro.style        |   3 +
 Telegram/SourceFiles/intro/intro_qr.cpp       | 240 ++++++++++++++++++
 Telegram/SourceFiles/intro/intro_qr.h         |  64 +++++
 Telegram/SourceFiles/intro/introcode.cpp      |   2 +-
 Telegram/SourceFiles/intro/introphone.cpp     |  11 -
 Telegram/SourceFiles/intro/introphone.h       |   3 -
 Telegram/SourceFiles/intro/introstart.cpp     |   4 +-
 Telegram/SourceFiles/main/main_account.cpp    |  44 ++--
 Telegram/SourceFiles/main/main_account.h      |   4 +
 Telegram/SourceFiles/mainwidget.cpp           |  40 ++-
 Telegram/SourceFiles/mainwidget.h             |   3 +-
 .../SourceFiles/storage/file_download.cpp     |   2 +-
 Telegram/SourceFiles/storage/file_download.h  |   2 +-
 Telegram/ThirdParty/QR                        |   1 +
 Telegram/gyp/Telegram.gyp                     |   1 +
 Telegram/gyp/telegram/sources.txt             |   2 +
 Telegram/lib_qr                               |   1 +
 19 files changed, 380 insertions(+), 57 deletions(-)
 create mode 100644 Telegram/SourceFiles/intro/intro_qr.cpp
 create mode 100644 Telegram/SourceFiles/intro/intro_qr.h
 create mode 160000 Telegram/ThirdParty/QR
 create mode 160000 Telegram/lib_qr

diff --git a/.gitmodules b/.gitmodules
index c0880c9cd..56e46263b 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -52,3 +52,9 @@
 [submodule "Telegram/ThirdParty/expected"]
 	path = Telegram/ThirdParty/expected
 	url = https://github.com/TartanLlama/expected
+[submodule "Telegram/ThirdParty/QR"]
+	path = Telegram/ThirdParty/QR
+	url = https://github.com/nayuki/QR-Code-generator
+[submodule "Telegram/lib_qr"]
+	path = Telegram/lib_qr
+	url = https://github.com/desktop-app/lib_qr.git
diff --git a/Telegram/Resources/langs/lang.strings b/Telegram/Resources/langs/lang.strings
index f72fad17b..78983bab6 100644
--- a/Telegram/Resources/langs/lang.strings
+++ b/Telegram/Resources/langs/lang.strings
@@ -178,6 +178,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_photo_caption" = "Caption";
 "lng_photos_comment" = "Comment";
 
+"lng_intro_qr_title" = "Scan From Mobile Telegram";
+"lng_intro_qr_description" = "Please scan this code from your Telegram on iOS or Android.";
+"lng_intro_qr_skip" = "Log in using phone";
+
 "lng_phone_title" = "Your Phone Number";
 "lng_phone_desc" = "Please confirm your country code and\nenter your mobile phone number.";
 "lng_country_code" = "Country Code";
diff --git a/Telegram/SourceFiles/intro/intro.style b/Telegram/SourceFiles/intro/intro.style
index fdae237d7..01852c497 100644
--- a/Telegram/SourceFiles/intro/intro.style
+++ b/Telegram/SourceFiles/intro/intro.style
@@ -160,3 +160,6 @@ introBackButton: IconButton(defaultIconButton) {
 	}
 }
 
+introQrTop: 90px;
+introQrPixel: 50px; // large enough
+introQrMaxSize: 170px;
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
new file mode 100644
index 000000000..07770fcd4
--- /dev/null
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -0,0 +1,240 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "intro/intro_qr.h"
+
+#include "lang/lang_keys.h"
+#include "intro/introphone.h"
+#include "ui/widgets/buttons.h"
+#include "ui/widgets/labels.h"
+#include "ui/wrap/fade_wrap.h"
+#include "main/main_account.h"
+#include "boxes/confirm_box.h"
+#include "core/application.h"
+#include "base/unixtime.h"
+#include "qr/qr_generate.h"
+#include "styles/style_intro.h"
+
+namespace Intro {
+namespace {
+
+[[nodiscard]] QImage TelegramLogoImage(int size) {
+	return Core::App().logo().scaled(
+		size,
+		size,
+		Qt::KeepAspectRatio,
+		Qt::SmoothTransformation);
+}
+
+[[nodiscard]] QImage TelegramQrExact(const Qr::Data &data, int pixel) {
+	return Qr::ReplaceCenter(
+		Qr::Generate(data, pixel),
+		TelegramLogoImage(Qr::ReplaceSize(data, pixel)));
+}
+
+[[nodiscard]] QImage TelegramQr(const Qr::Data &data, int pixel, int max = 0) {
+	Expects(data.size > 0);
+
+	if (max > 0 && data.size * pixel > max) {
+		pixel = std::max(max / data.size, 1);
+	}
+	return TelegramQrExact(data, pixel * style::DevicePixelRatio());
+}
+
+[[nodiscard]] QImage TelegramQr(const QString &text, int pixel, int max) {
+	return TelegramQr(Qr::Encode(text), pixel, max);
+}
+
+[[nodiscard]] not_null<Ui::RpWidget*> PrepareQrWidget(
+		not_null<QWidget*> parent,
+		rpl::producer<QImage> images) {
+	auto result = Ui::CreateChild<Ui::RpWidget>(parent.get());
+	auto current = result->lifetime().make_state<QImage>();
+	std::move(
+		images
+	) | rpl::start_with_next([=](QImage &&image) {
+		result->resize(image.size() / cIntRetinaFactor());
+		*current = std::move(image);
+		result->update();
+	}, result->lifetime());
+	result->paintRequest(
+	) | rpl::filter([=] {
+		return !current->isNull();
+	}) | rpl::start_with_next([=](QRect clip) {
+		QPainter(result).drawImage(
+			QRect(QPoint(), current->size() / cIntRetinaFactor()),
+			*current);
+	}, result->lifetime());
+	return result;
+}
+
+} // namespace
+
+QrWidget::QrWidget(
+	QWidget *parent,
+	not_null<Main::Account*> account,
+	not_null<Widget::Data*> data)
+: Step(parent, account, data)
+, _code(PrepareQrWidget(this, _qrImages.events()))
+, _refreshTimer([=] { refreshCode(); }) {
+	setTitleText(tr::lng_intro_qr_title());
+	setDescriptionText(tr::lng_intro_qr_description());
+	setErrorCentered(true);
+
+	account->destroyStaleAuthorizationKeys();
+	account->mtpUpdates(
+	) | rpl::start_with_next([=](const MTPUpdates &updates) {
+		checkForTokenUpdate(updates);
+	}, lifetime());
+
+	_code->widthValue(
+	) | rpl::start_with_next([=] {
+		updateCodeGeometry();
+	}, _code->lifetime());
+	_code->show();
+
+	refreshCode();
+}
+
+void QrWidget::resizeEvent(QResizeEvent *e) {
+	Step::resizeEvent(e);
+	updateCodeGeometry();
+}
+
+void QrWidget::checkForTokenUpdate(const MTPUpdates &updates) {
+	updates.match([&](const MTPDupdateShort &data) {
+		checkForTokenUpdate(data.vupdate());
+	}, [&](const MTPDupdates &data) {
+		for (const auto &update : data.vupdates().v) {
+			checkForTokenUpdate(update);
+		}
+	}, [&](const MTPDupdatesCombined &data) {
+		for (const auto &update : data.vupdates().v) {
+			checkForTokenUpdate(update);
+		}
+	}, [](const auto &) {});
+}
+
+void QrWidget::checkForTokenUpdate(const MTPUpdate &update) {
+	update.match([&](const MTPDupdateLoginToken &data) {
+		if (_requestId) {
+			_forceRefresh = true;
+		} else {
+			_refreshTimer.cancel();
+			refreshCode();
+		}
+	}, [](const auto &) {});
+}
+
+void QrWidget::updateCodeGeometry() {
+	_code->moveToLeft(
+		(width() - _code->width()) / 2,
+		contentTop() + st::introQrTop);
+}
+
+void QrWidget::submit() {
+	goReplace<PhoneWidget>();
+}
+
+rpl::producer<QString> QrWidget::nextButtonText() const {
+	return tr::lng_intro_qr_skip();
+}
+
+void QrWidget::refreshCode() {
+	if (_requestId) {
+		return;
+	}
+	_requestId = _api.request(MTPauth_ExportLoginToken(
+		MTP_int(ApiId),
+		MTP_string(ApiHash),
+		MTP_vector<MTPint>(0)
+	)).done([=](const MTPauth_LoginToken &result) {
+		handleTokenResult(result);
+	}).fail([=](const RPCError &error) {
+		showTokenError(error);
+	}).send();
+}
+
+void QrWidget::handleTokenResult(const MTPauth_LoginToken &result) {
+	result.match([&](const MTPDauth_loginToken &data) {
+		_requestId = 0;
+		showToken(data.vtoken().v);
+
+		if (base::take(_forceRefresh)) {
+			refreshCode();
+		} else {
+			const auto left = data.vexpires().v - base::unixtime::now();
+			_refreshTimer.callOnce(std::max(left, 1) * crl::time(1000));
+		}
+	}, [&](const MTPDauth_loginTokenMigrateTo &data) {
+		importTo(data.vdc_id().v, data.vtoken().v);
+	}, [&](const MTPDauth_loginTokenSuccess &data) {
+		done(data.vauthorization());
+	});
+}
+
+void QrWidget::showTokenError(const RPCError &error) {
+	_requestId = 0;
+	if (base::take(_forceRefresh)) {
+		refreshCode();
+	} else {
+		showError(rpl::single(error.type()));
+	}
+}
+
+void QrWidget::showToken(const QByteArray &token) {
+	const auto encoded = token.toBase64(QByteArray::Base64UrlEncoding);
+	const auto text = "tg_login/" + encoded;
+	_qrImages.fire(TelegramQr(text, st::introQrPixel, st::introQrMaxSize));
+}
+
+void QrWidget::importTo(MTP::DcId dcId, const QByteArray &token) {
+	Expects(_requestId != 0);
+
+	_requestId = _api.request(MTPauth_ImportLoginToken(
+		MTP_bytes(token)
+	)).done([=](const MTPauth_LoginToken &result) {
+		handleTokenResult(result);
+	}).fail([=](const RPCError &error) {
+		showTokenError(error);
+	}).toDC(dcId).send();
+}
+
+void QrWidget::done(const MTPauth_Authorization &authorization) {
+	authorization.match([&](const MTPDauth_authorization &data) {
+		if (data.vuser().type() != mtpc_user
+			|| !data.vuser().c_user().is_self()) {
+			showError(rpl::single(Lang::Hard::ServerError()));
+			return;
+		}
+		const auto phone = data.vuser().c_user().vphone().value_or_empty();
+		cSetLoggedPhoneNumber(phone);
+		finish(data.vuser());
+	}, [&](const MTPDauth_authorizationSignUpRequired &data) {
+		_requestId = 0;
+		LOG(("API Error: Unexpected auth.authorizationSignUpRequired."));
+		showError(rpl::single(Lang::Hard::ServerError()));
+	});
+}
+
+void QrWidget::activate() {
+	Step::activate();
+	_code->show();
+}
+
+void QrWidget::finished() {
+	Step::finished();
+	_refreshTimer.cancel();
+	rpcInvalidate();
+	cancelled();
+}
+
+void QrWidget::cancelled() {
+	_api.request(base::take(_requestId)).cancel();
+}
+
+} // namespace Intro
diff --git a/Telegram/SourceFiles/intro/intro_qr.h b/Telegram/SourceFiles/intro/intro_qr.h
new file mode 100644
index 000000000..af2d3f7fc
--- /dev/null
+++ b/Telegram/SourceFiles/intro/intro_qr.h
@@ -0,0 +1,64 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "ui/countryinput.h"
+#include "intro/introwidget.h"
+#include "mtproto/sender.h"
+#include "base/timer.h"
+
+namespace Ui {
+class PhonePartInput;
+class CountryCodeInput;
+class RoundButton;
+class FlatLabel;
+} // namespace Ui
+
+namespace Intro {
+
+class QrWidget : public Widget::Step {
+public:
+	QrWidget(
+		QWidget *parent,
+		not_null<Main::Account*> account,
+		not_null<Widget::Data*> data);
+
+	void activate() override;
+	void finished() override;
+	void cancelled() override;
+	void submit() override;
+	rpl::producer<QString> nextButtonText() const override;
+
+	bool hasBack() const override {
+		return true;
+	}
+
+protected:
+	void resizeEvent(QResizeEvent *e) override;
+
+private:
+	void refreshCode();
+	void updateCodeGeometry();
+	void checkForTokenUpdate(const MTPUpdates &updates);
+	void checkForTokenUpdate(const MTPUpdate &update);
+	void handleTokenResult(const MTPauth_LoginToken &result);
+	void showTokenError(const RPCError &error);
+	void importTo(MTP::DcId dcId, const QByteArray &token);
+	void showToken(const QByteArray &token);
+	void done(const MTPauth_Authorization &authorization);
+
+	rpl::event_stream<QImage> _qrImages;
+	not_null<Ui::RpWidget*> _code;
+	base::Timer _refreshTimer;
+	MTP::Sender _api;
+	mtpRequestId _requestId = 0;
+	bool _forceRefresh = false;
+
+};
+
+} // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introcode.cpp b/Telegram/SourceFiles/intro/introcode.cpp
index 26736e1a8..32eee158b 100644
--- a/Telegram/SourceFiles/intro/introcode.cpp
+++ b/Telegram/SourceFiles/intro/introcode.cpp
@@ -236,7 +236,7 @@ void CodeWidget::codeSubmitDone(const MTPauth_Authorization &result) {
 	result.match([&](const MTPDauth_authorization &data) {
 		if (data.vuser().type() != mtpc_user
 			|| !data.vuser().c_user().is_self()) {
-			showCodeError(rpl::single(Lang::Hard::ServerError()));
+			showError(rpl::single(Lang::Hard::ServerError()));
 			return;
 		}
 		cSetLoggedPhoneNumber(getData()->phone);
diff --git a/Telegram/SourceFiles/intro/introphone.cpp b/Telegram/SourceFiles/intro/introphone.cpp
index d9a3e2d5f..ea838a170 100644
--- a/Telegram/SourceFiles/intro/introphone.cpp
+++ b/Telegram/SourceFiles/intro/introphone.cpp
@@ -69,13 +69,6 @@ void PhoneWidget::resizeEvent(QResizeEvent *e) {
 	auto phoneTop = _country->y() + _country->height() + st::introPhoneTop;
 	_code->moveToLeft(contentLeft(), phoneTop);
 	_phone->moveToLeft(contentLeft() + _country->width() - st::introPhone.width, phoneTop);
-	updateSignupGeometry();
-}
-
-void PhoneWidget::updateSignupGeometry() {
-	if (_signup) {
-		_signup->moveToLeft(contentLeft() + st::buttonRadius, contentTop() + st::introDescriptionTop);
-	}
 }
 
 void PhoneWidget::showPhoneError(rpl::producer<QString> text) {
@@ -85,10 +78,6 @@ void PhoneWidget::showPhoneError(rpl::producer<QString> text) {
 
 void PhoneWidget::hidePhoneError() {
 	hideError();
-	if (_signup) {
-		_signup->hide(anim::type::instant);
-		showDescription();
-	}
 }
 
 void PhoneWidget::countryChanged() {
diff --git a/Telegram/SourceFiles/intro/introphone.h b/Telegram/SourceFiles/intro/introphone.h
index 60e706345..71316cdfe 100644
--- a/Telegram/SourceFiles/intro/introphone.h
+++ b/Telegram/SourceFiles/intro/introphone.h
@@ -48,7 +48,6 @@ private slots:
 	void onCheckRequest();
 
 private:
-	void updateSignupGeometry();
 	void countryChanged();
 
 	void phoneSubmitDone(const MTPauth_SentCode &result);
@@ -66,8 +65,6 @@ private:
 	object_ptr<Ui::CountryCodeInput> _code;
 	object_ptr<Ui::PhonePartInput> _phone;
 
-	object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _signup = { nullptr };
-
 	QString _sentPhone;
 	mtpRequestId _sentRequest = 0;
 
diff --git a/Telegram/SourceFiles/intro/introstart.cpp b/Telegram/SourceFiles/intro/introstart.cpp
index 8ee0b1e5c..cd70a996e 100644
--- a/Telegram/SourceFiles/intro/introstart.cpp
+++ b/Telegram/SourceFiles/intro/introstart.cpp
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "intro/introstart.h"
 
 #include "lang/lang_keys.h"
-#include "intro/introphone.h"
+#include "intro/intro_qr.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
 
@@ -26,7 +26,7 @@ StartWidget::StartWidget(
 }
 
 void StartWidget::submit() {
-	goNext<PhoneWidget>();
+	goNext<QrWidget>();
 }
 
 rpl::producer<QString> StartWidget::nextButtonText() const {
diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index 5fbbd0b64..faa11e7cc 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -120,21 +120,6 @@ void Account::createSession(
 	Expects(_session == nullptr);
 	Expects(_sessionValue.current() == nullptr);
 
-	_mtp->setUpdatesHandler(::rpcDone([](
-		const mtpPrime *from,
-		const mtpPrime *end) {
-		if (const auto main = App::main()) {
-			return main->updateReceived(from, end);
-		}
-		return true;
-	}));
-	_mtp->setGlobalFailHandler(::rpcFail([=](const RPCError &error) {
-		if (sessionExists()) {
-			crl::on_main(&session(), [=] { logOut(); });
-		}
-		return true;
-	}));
-
 	_session = std::make_unique<Session>(this, user, std::move(settings));
 	_sessionValue = _session.get();
 
@@ -152,7 +137,6 @@ void Account::destroySession() {
 		return;
 	}
 	session().data().clear();
-	_mtp->clearGlobalHandlers();
 
 	_sessionValue = nullptr;
 	_session = nullptr;
@@ -192,6 +176,14 @@ rpl::producer<MTP::Instance*> Account::mtpChanges() const {
 	return _mtpValue.changes();
 }
 
+rpl::producer<MTPUpdates> Account::mtpUpdates() const {
+	return _mtpUpdates.events();
+}
+
+rpl::producer<> Account::mtpNewSessionCreated() const {
+	return _mtpNewSessionCreated.events();
+}
+
 void Account::setMtpMainDcId(MTP::DcId mainDcId) {
 	Expects(!_mtp);
 
@@ -344,6 +336,26 @@ void Account::startMtp() {
 	_mtp->setUserPhone(cLoggedPhoneNumber());
 	_mtpConfig.mainDcId = _mtp->mainDcId();
 
+	_mtp->setUpdatesHandler(::rpcDone([=](
+			const mtpPrime *from,
+			const mtpPrime *end) {
+		auto newSession = MTPNewSession();
+		auto updates = MTPUpdates();
+		if (updates.read(from, end)) {
+			_mtpUpdates.fire(std::move(updates));
+		} else if (newSession.read(from, end)) {
+			_mtpNewSessionCreated.fire({});
+		} else {
+			return false;
+		}
+		return true;
+	}));
+	_mtp->setGlobalFailHandler(::rpcFail([=](const RPCError &error) {
+		if (sessionExists()) {
+			crl::on_main(&session(), [=] { logOut(); });
+		}
+		return true;
+	}));
 	_mtp->setStateChangedHandler([](MTP::ShiftedDcId dc, int32 state) {
 		if (dc == MTP::maindc()) {
 			Global::RefConnectionTypeChanged().notify();
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 8783e9a08..5e4fc1238 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -56,6 +56,8 @@ public:
 		QByteArray &&selfSerialized,
 		int32 selfStreamVersion);
 	[[nodiscard]] Settings *getSessionSettings();
+	[[nodiscard]] rpl::producer<> mtpNewSessionCreated() const;
+	[[nodiscard]] rpl::producer<MTPUpdates> mtpUpdates() const;
 
 	// Serialization.
 	[[nodiscard]] QByteArray serializeMtpAuthorization() const;
@@ -86,6 +88,8 @@ private:
 	std::unique_ptr<MTP::Instance> _mtp;
 	rpl::variable<MTP::Instance*> _mtpValue;
 	std::unique_ptr<MTP::Instance> _mtpForKeysDestroy;
+	rpl::event_stream<MTPUpdates> _mtpUpdates;
+	rpl::event_stream<> _mtpNewSessionCreated;
 	rpl::event_stream<> _configUpdates;
 
 	std::unique_ptr<Session> _session;
diff --git a/Telegram/SourceFiles/mainwidget.cpp b/Telegram/SourceFiles/mainwidget.cpp
index ee09ab726..58e007dbb 100644
--- a/Telegram/SourceFiles/mainwidget.cpp
+++ b/Telegram/SourceFiles/mainwidget.cpp
@@ -93,6 +93,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "export/view/export_view_top_bar.h"
 #include "export/view/export_view_panel_controller.h"
 #include "main/main_session.h"
+#include "main/main_account.h"
 #include "support/support_helper.h"
 #include "storage/storage_facade.h"
 #include "storage/storage_shared_media.h"
@@ -430,6 +431,16 @@ MainWidget::MainWidget(
 		[this] { updateControlsGeometry(); },
 		lifetime());
 
+	session().account().mtpUpdates(
+	) | rpl::start_with_next([=](const MTPUpdates &updates) {
+		mtpUpdateReceived(updates);
+	}, lifetime());
+
+	session().account().mtpNewSessionCreated(
+	) | rpl::start_with_next([=] {
+		mtpNewSessionCreated();
+	}, lifetime());
+
 	// MSVC BUG + REGRESSION rpl::mappers::tuple :(
 	using namespace rpl::mappers;
 	_controller->activeChatValue(
@@ -3673,35 +3684,22 @@ void MainWidget::checkIdleFinish() {
 	}
 }
 
-bool MainWidget::updateReceived(const mtpPrime *from, const mtpPrime *end) {
-	if (end <= from) {
-		return false;
-	}
-
+void MainWidget::mtpNewSessionCreated() {
 	session().checkAutoLock();
+	updSeq = 0;
+	MTP_LOG(0, ("getDifference { after new_session_created }%1"
+		).arg(cTestMode() ? " TESTMODE" : ""));
+	getDifference();
+}
 
-	if (mtpTypeId(*from) == mtpc_new_session_created) {
-		MTPNewSession newSession;
-		if (!newSession.read(from, end)) {
-			return false;
-		}
-		updSeq = 0;
-		MTP_LOG(0, ("getDifference { after new_session_created }%1").arg(cTestMode() ? " TESTMODE" : ""));
-		getDifference();
-		return true;
-	}
-	MTPUpdates updates;
-	if (!updates.read(from, end)) {
-		return false;
-	}
-
+void MainWidget::mtpUpdateReceived(const MTPUpdates &updates) {
+	session().checkAutoLock();
 	_lastUpdateTime = crl::now();
 	_noUpdatesTimer.callOnce(kNoUpdatesTimeout);
 	if (!requestingDifference()
 		|| HasForceLogoutNotification(updates)) {
 		feedUpdates(updates);
 	}
-	return true;
 }
 
 void MainWidget::feedUpdates(const MTPUpdates &updates, uint64 randomId) {
diff --git a/Telegram/SourceFiles/mainwidget.h b/Telegram/SourceFiles/mainwidget.h
index d07cd1ddc..6a41d156e 100644
--- a/Telegram/SourceFiles/mainwidget.h
+++ b/Telegram/SourceFiles/mainwidget.h
@@ -133,7 +133,6 @@ public:
 	void incrementSticker(DocumentData *sticker);
 
 	void activate();
-	[[nodiscard]] bool updateReceived(const mtpPrime *from, const mtpPrime *end);
 
 	void refreshDialog(Dialogs::Key key);
 	void removeDialog(Dialogs::Key key);
@@ -394,6 +393,8 @@ private:
 	bool failChannelDifference(ChannelData *channel, const RPCError &err);
 	void failDifferenceStartTimerFor(ChannelData *channel);
 
+	void mtpUpdateReceived(const MTPUpdates &updates);
+	void mtpNewSessionCreated();
 	void feedUpdateVector(
 		const MTPVector<MTPUpdate> &updates,
 		bool skipMessageIds = false);
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index ffac1874e..ae046b0d4 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -60,7 +60,7 @@ void Downloader::requestedAmountIncrement(MTP::DcId dcId, int index, int amount)
 	using namespace rpl::mappers;
 
 	auto it = _requestedBytesAmount.find(dcId);
-	if (it == _requestedBytesAmount.cend()) {
+	if (it == _requestedBytesAmount.end()) {
 		it = _requestedBytesAmount.emplace(dcId, RequestedInDc { { 0 } }).first;
 	}
 	it->second[index] += amount;
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index c15d8745d..32f20677b 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -79,7 +79,7 @@ private:
 	int _priority = 1;
 
 	using RequestedInDc = std::array<int64, MTP::kDownloadSessionsCount>;
-	std::map<MTP::DcId, RequestedInDc> _requestedBytesAmount;
+	base::flat_map<MTP::DcId, RequestedInDc> _requestedBytesAmount;
 
 	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
 	base::Timer _killDownloadSessionsTimer;
diff --git a/Telegram/ThirdParty/QR b/Telegram/ThirdParty/QR
new file mode 160000
index 000000000..67c62461d
--- /dev/null
+++ b/Telegram/ThirdParty/QR
@@ -0,0 +1 @@
+Subproject commit 67c62461d380352500fc39557fd9f046b7fe1d18
diff --git a/Telegram/gyp/Telegram.gyp b/Telegram/gyp/Telegram.gyp
index 7f080fba8..ac05463a9 100644
--- a/Telegram/gyp/Telegram.gyp
+++ b/Telegram/gyp/Telegram.gyp
@@ -75,6 +75,7 @@
       '<(submodules_loc)/codegen/codegen.gyp:codegen_style',
       '<(submodules_loc)/lib_base/lib_base.gyp:lib_base',
       '<(submodules_loc)/lib_ui/lib_ui.gyp:lib_ui',
+      '<(submodules_loc)/lib_qr/lib_qr.gyp:lib_qr',
       '<(third_party_loc)/libtgvoip/libtgvoip.gyp:libtgvoip',
       '<(submodules_loc)/lib_lottie/lib_lottie.gyp:lib_lottie',
       'tests/tests.gyp:tests',
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index 0bd944970..ca6bea78e 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -444,6 +444,8 @@
 <(src_loc)/intro/introsignup.h
 <(src_loc)/intro/introstart.cpp
 <(src_loc)/intro/introstart.h
+<(src_loc)/intro/intro_qr.cpp
+<(src_loc)/intro/intro_qr.h
 <(src_loc)/lang/lang_cloud_manager.cpp
 <(src_loc)/lang/lang_cloud_manager.h
 <(src_loc)/lang/lang_file_parser.cpp
diff --git a/Telegram/lib_qr b/Telegram/lib_qr
new file mode 160000
index 000000000..6111aa3ce
--- /dev/null
+++ b/Telegram/lib_qr
@@ -0,0 +1 @@
+Subproject commit 6111aa3cef49d481d6450f463cfc4fe482755db7

From 32d567120b2827bc8f1256b471efbb23fb15b8d0 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 22 Nov 2019 15:45:23 +0300
Subject: [PATCH 53/91] Change URL in Windows setup script.

---
 Telegram/build/setup.iss | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/build/setup.iss b/Telegram/build/setup.iss
index a599e247e..819ad5618 100644
--- a/Telegram/build/setup.iss
+++ b/Telegram/build/setup.iss
@@ -1,7 +1,7 @@
 #define MyAppShortName "Telegram"
 #define MyAppName "Telegram Desktop"
 #define MyAppPublisher "Telegram FZ-LLC"
-#define MyAppURL "https://tdesktop.com"
+#define MyAppURL "https://desktop.telegram.org"
 #define MyAppExeName "Telegram.exe"
 #define MyAppId "53F49750-6209-4FBF-9CA8-7A333C87D1ED"
 

From 339a80e192085e095bbae182422a6a2d5199b48c Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 26 Nov 2019 14:10:44 +0300
Subject: [PATCH 54/91] Improve QR code login layout.

---
 Telegram/Resources/langs/lang.strings        |   6 +-
 Telegram/SourceFiles/intro/intro.style       |  21 +-
 Telegram/SourceFiles/intro/intro_qr.cpp      | 142 +++--
 Telegram/SourceFiles/intro/intro_qr.h        |  16 +-
 Telegram/SourceFiles/intro/intro_step.cpp    | 508 +++++++++++++++++
 Telegram/SourceFiles/intro/intro_step.h      | 192 +++++++
 Telegram/SourceFiles/intro/introcode.cpp     |  24 +-
 Telegram/SourceFiles/intro/introcode.h       |  13 +-
 Telegram/SourceFiles/intro/introphone.cpp    |  10 +-
 Telegram/SourceFiles/intro/introphone.h      |   8 +-
 Telegram/SourceFiles/intro/intropwdcheck.cpp |   9 +-
 Telegram/SourceFiles/intro/intropwdcheck.h   |   9 +-
 Telegram/SourceFiles/intro/introsignup.cpp   |  29 +-
 Telegram/SourceFiles/intro/introsignup.h     |   8 +-
 Telegram/SourceFiles/intro/introstart.cpp    |   4 +-
 Telegram/SourceFiles/intro/introstart.h      |   8 +-
 Telegram/SourceFiles/intro/introwidget.cpp   | 556 ++-----------------
 Telegram/SourceFiles/intro/introwidget.h     | 273 ++-------
 Telegram/gyp/telegram/sources.txt            |   2 +
 Telegram/lib_qr                              |   2 +-
 20 files changed, 1031 insertions(+), 809 deletions(-)
 create mode 100644 Telegram/SourceFiles/intro/intro_step.cpp
 create mode 100644 Telegram/SourceFiles/intro/intro_step.h

diff --git a/Telegram/Resources/langs/lang.strings b/Telegram/Resources/langs/lang.strings
index 78983bab6..58094bfa5 100644
--- a/Telegram/Resources/langs/lang.strings
+++ b/Telegram/Resources/langs/lang.strings
@@ -179,8 +179,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_photos_comment" = "Comment";
 
 "lng_intro_qr_title" = "Scan From Mobile Telegram";
-"lng_intro_qr_description" = "Please scan this code from your Telegram on iOS or Android.";
-"lng_intro_qr_skip" = "Log in using phone";
+"lng_intro_qr_step1" = "**1.** Open Telegram on your phone";
+"lng_intro_qr_step2" = "**2.** Go to **Settings** and tap \"Scan QR code\"";
+"lng_intro_qr_step3" = "**3.** Scan this image to Log In";
+"lng_intro_qr_skip" = "Or log in using your phone number";
 
 "lng_phone_title" = "Your Phone Number";
 "lng_phone_desc" = "Please confirm your country code and\nenter your mobile phone number.";
diff --git a/Telegram/SourceFiles/intro/intro.style b/Telegram/SourceFiles/intro/intro.style
index 01852c497..95af195b7 100644
--- a/Telegram/SourceFiles/intro/intro.style
+++ b/Telegram/SourceFiles/intro/intro.style
@@ -74,8 +74,9 @@ introPlaneHeight: 38px;
 introHeight: 406px;
 introStepTopMin: 76px;
 introStepWidth: 380px;
-introStepHeight: 266px;
-introStepHeightAdd: 30px;
+introNextTop: 266px;
+introStepHeight: 384px;
+introContentTopAdd: 30px;
 introStepHeightFull: 590px;
 introSlideDuration: 200;
 introCoverDuration: 200;
@@ -160,6 +161,20 @@ introBackButton: IconButton(defaultIconButton) {
 	}
 }
 
-introQrTop: 90px;
+introQrTop: 0px;
 introQrPixel: 50px; // large enough
 introQrMaxSize: 170px;
+introQrLabelsWidth: 292px;
+introQrTitle: FlatLabel(defaultFlatLabel) {
+	textFg: introTitleFg;
+	style: TextStyle(defaultTextStyle) {
+		font: font(20px semibold);
+		linkFont: font(20px semibold);
+		linkFontOver: font(20px semibold underline);
+	}
+}
+introQrTitleTop: 196px;
+introQrStep: defaultFlatLabel;
+introQrStepsTop: 232px;
+introQrStepMargins: margins(0px, 8px, 0px, 0px);
+introQrSkipTop: 360px;
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index 07770fcd4..a7b6c1679 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -7,11 +7,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "intro/intro_qr.h"
 
-#include "lang/lang_keys.h"
 #include "intro/introphone.h"
+#include "lang/lang_keys.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
 #include "ui/wrap/fade_wrap.h"
+#include "ui/wrap/vertical_layout.h"
+#include "ui/text/text_utilities.h"
 #include "main/main_account.h"
 #include "boxes/confirm_box.h"
 #include "core/application.h"
@@ -20,14 +22,31 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "styles/style_intro.h"
 
 namespace Intro {
+namespace details {
 namespace {
 
 [[nodiscard]] QImage TelegramLogoImage(int size) {
-	return Core::App().logo().scaled(
-		size,
-		size,
+	constexpr auto kScale = 0.8;
+	const auto used = int(size * kScale);
+	const auto adjusted = used + ((used % 2) + (size % 2)) % 2;
+	const auto image = Core::App().logo().scaled(
+		adjusted,
+		adjusted,
 		Qt::KeepAspectRatio,
 		Qt::SmoothTransformation);
+	auto result = QImage(size, size, QImage::Format_ARGB32_Premultiplied);
+	result.fill(Qt::transparent);
+	{
+		QPainter p(&result);
+		p.drawImage(
+			QRect(
+			(size - adjusted) / 2,
+				(size - adjusted) / 2,
+				adjusted,
+				adjusted),
+			image);
+	}
+	return result;
 }
 
 [[nodiscard]] QImage TelegramQrExact(const Qr::Data &data, int pixel) {
@@ -46,17 +65,22 @@ namespace {
 }
 
 [[nodiscard]] QImage TelegramQr(const QString &text, int pixel, int max) {
-	return TelegramQr(Qr::Encode(text), pixel, max);
+	return TelegramQr(
+		Qr::Encode(text, Qr::Redundancy::Quartile),
+		pixel,
+		max);
 }
 
 [[nodiscard]] not_null<Ui::RpWidget*> PrepareQrWidget(
 		not_null<QWidget*> parent,
-		rpl::producer<QImage> images) {
+		rpl::producer<QByteArray> codes) {
 	auto result = Ui::CreateChild<Ui::RpWidget>(parent.get());
 	auto current = result->lifetime().make_state<QImage>();
 	std::move(
-		images
-	) | rpl::start_with_next([=](QImage &&image) {
+		codes
+	) | rpl::map([](const QByteArray &code) {
+		return TelegramQr(code, st::introQrPixel, st::introQrMaxSize);
+	}) | rpl::start_with_next([=](QImage &&image) {
 		result->resize(image.size() / cIntRetinaFactor());
 		*current = std::move(image);
 		result->update();
@@ -77,12 +101,11 @@ namespace {
 QrWidget::QrWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
-	not_null<Widget::Data*> data)
-: Step(parent, account, data)
-, _code(PrepareQrWidget(this, _qrImages.events()))
-, _refreshTimer([=] { refreshCode(); }) {
-	setTitleText(tr::lng_intro_qr_title());
-	setDescriptionText(tr::lng_intro_qr_description());
+	not_null<Data*> data)
+	: Step(parent, account, data)
+	, _refreshTimer([=] { refreshCode(); }) {
+	setTitleText(rpl::single(QString()));
+	setDescriptionText(rpl::single(QString()));
 	setErrorCentered(true);
 
 	account->destroyStaleAuthorizationKeys();
@@ -91,20 +114,10 @@ QrWidget::QrWidget(
 		checkForTokenUpdate(updates);
 	}, lifetime());
 
-	_code->widthValue(
-	) | rpl::start_with_next([=] {
-		updateCodeGeometry();
-	}, _code->lifetime());
-	_code->show();
-
+	setupControls();
 	refreshCode();
 }
 
-void QrWidget::resizeEvent(QResizeEvent *e) {
-	Step::resizeEvent(e);
-	updateCodeGeometry();
-}
-
 void QrWidget::checkForTokenUpdate(const MTPUpdates &updates) {
 	updates.match([&](const MTPDupdateShort &data) {
 		checkForTokenUpdate(data.vupdate());
@@ -130,18 +143,77 @@ void QrWidget::checkForTokenUpdate(const MTPUpdate &update) {
 	}, [](const auto &) {});
 }
 
-void QrWidget::updateCodeGeometry() {
-	_code->moveToLeft(
-		(width() - _code->width()) / 2,
-		contentTop() + st::introQrTop);
-}
-
 void QrWidget::submit() {
 	goReplace<PhoneWidget>();
 }
 
 rpl::producer<QString> QrWidget::nextButtonText() const {
-	return tr::lng_intro_qr_skip();
+	return rpl::single(QString());
+}
+
+void QrWidget::setupControls() {
+	const auto code = PrepareQrWidget(this, _qrCodes.events());
+	rpl::combine(
+		sizeValue(),
+		code->widthValue()
+	) | rpl::start_with_next([=](QSize size, int codeWidth) {
+		code->moveToLeft(
+			(size.width() - codeWidth) / 2,
+			contentTop() + st::introQrTop);
+	}, code->lifetime());
+
+	const auto title = Ui::CreateChild<Ui::FlatLabel>(
+		this,
+		tr::lng_intro_qr_title(),
+		st::introQrTitle);
+	rpl::combine(
+		sizeValue(),
+		title->widthValue()
+	) | rpl::start_with_next([=](QSize size, int titleWidth) {
+		title->moveToLeft(
+			(size.width() - st::introQrLabelsWidth) / 2,
+			contentTop() + st::introQrTitleTop);
+	}, title->lifetime());
+
+	const auto steps = Ui::CreateChild<Ui::VerticalLayout>(this);
+	const auto texts = {
+		tr::lng_intro_qr_step1,
+		tr::lng_intro_qr_step2,
+		tr::lng_intro_qr_step3,
+	};
+	for (const auto &text : texts) {
+		steps->add(
+			object_ptr<Ui::FlatLabel>(
+				this,
+				text(Ui::Text::RichLangValue),
+				st::introQrStep),
+			st::introQrStepMargins);
+	}
+	steps->resizeToWidth(st::introQrLabelsWidth);
+	rpl::combine(
+		sizeValue(),
+		steps->widthValue()
+	) | rpl::start_with_next([=](QSize size, int stepsWidth) {
+		steps->moveToLeft(
+			(size.width() - stepsWidth) / 2,
+			contentTop() + st::introQrStepsTop);
+	}, steps->lifetime());
+
+	const auto skip = Ui::CreateChild<Ui::LinkButton>(
+		this,
+		tr::lng_intro_qr_skip(tr::now));
+	rpl::combine(
+		sizeValue(),
+		skip->widthValue()
+	) | rpl::start_with_next([=](QSize size, int skipWidth) {
+		skip->moveToLeft(
+			(size.width() - skipWidth) / 2,
+			contentTop() + st::introQrSkipTop);
+	}, skip->lifetime());
+
+	skip->setClickedCallback([=] {
+		goNext<PhoneWidget>();
+	});
 }
 
 void QrWidget::refreshCode() {
@@ -188,8 +260,7 @@ void QrWidget::showTokenError(const RPCError &error) {
 
 void QrWidget::showToken(const QByteArray &token) {
 	const auto encoded = token.toBase64(QByteArray::Base64UrlEncoding);
-	const auto text = "tg_login/" + encoded;
-	_qrImages.fire(TelegramQr(text, st::introQrPixel, st::introQrMaxSize));
+	_qrCodes.fire_copy("tg_login/" + encoded);
 }
 
 void QrWidget::importTo(MTP::DcId dcId, const QByteArray &token) {
@@ -223,7 +294,7 @@ void QrWidget::done(const MTPauth_Authorization &authorization) {
 
 void QrWidget::activate() {
 	Step::activate();
-	_code->show();
+	showChildren();
 }
 
 void QrWidget::finished() {
@@ -237,4 +308,5 @@ void QrWidget::cancelled() {
 	_api.request(base::take(_requestId)).cancel();
 }
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/intro_qr.h b/Telegram/SourceFiles/intro/intro_qr.h
index af2d3f7fc..fbcf1f5a9 100644
--- a/Telegram/SourceFiles/intro/intro_qr.h
+++ b/Telegram/SourceFiles/intro/intro_qr.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "ui/countryinput.h"
-#include "intro/introwidget.h"
+#include "intro/intro_step.h"
 #include "mtproto/sender.h"
 #include "base/timer.h"
 
@@ -20,13 +20,14 @@ class FlatLabel;
 } // namespace Ui
 
 namespace Intro {
+namespace details {
 
-class QrWidget : public Widget::Step {
+class QrWidget : public Step {
 public:
 	QrWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
-		not_null<Widget::Data*> data);
+		not_null<Data*> data);
 
 	void activate() override;
 	void finished() override;
@@ -38,12 +39,9 @@ public:
 		return true;
 	}
 
-protected:
-	void resizeEvent(QResizeEvent *e) override;
-
 private:
+	void setupControls();
 	void refreshCode();
-	void updateCodeGeometry();
 	void checkForTokenUpdate(const MTPUpdates &updates);
 	void checkForTokenUpdate(const MTPUpdate &update);
 	void handleTokenResult(const MTPauth_LoginToken &result);
@@ -52,8 +50,7 @@ private:
 	void showToken(const QByteArray &token);
 	void done(const MTPauth_Authorization &authorization);
 
-	rpl::event_stream<QImage> _qrImages;
-	not_null<Ui::RpWidget*> _code;
+	rpl::event_stream<QByteArray> _qrCodes;
 	base::Timer _refreshTimer;
 	MTP::Sender _api;
 	mtpRequestId _requestId = 0;
@@ -61,4 +58,5 @@ private:
 
 };
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/intro_step.cpp b/Telegram/SourceFiles/intro/intro_step.cpp
new file mode 100644
index 000000000..99100704c
--- /dev/null
+++ b/Telegram/SourceFiles/intro/intro_step.cpp
@@ -0,0 +1,508 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "intro/intro_step.h"
+
+#include "intro/introwidget.h"
+#include "storage/localstorage.h"
+#include "lang/lang_keys.h"
+#include "lang/lang_cloud_manager.h"
+#include "main/main_account.h"
+#include "apiwrap.h"
+#include "mainwindow.h"
+#include "boxes/confirm_box.h"
+#include "ui/text/text_utilities.h"
+#include "ui/widgets/labels.h"
+#include "ui/wrap/fade_wrap.h"
+#include "ui/effects/slide_animation.h"
+#include "data/data_user.h"
+#include "data/data_auto_download.h"
+#include "window/themes/window_theme.h"
+#include "facades.h"
+#include "app.h"
+#include "styles/style_intro.h"
+#include "styles/style_window.h"
+
+namespace Intro {
+namespace details {
+namespace {
+
+void PrepareSupportMode() {
+	using ::Data::AutoDownload::Full;
+
+	anim::SetDisabled(true);
+	Local::writeSettings();
+
+	Global::SetDesktopNotify(false);
+	Global::SetSoundNotify(false);
+	Auth().settings().autoDownload() = Full::FullDisabled();
+	Local::writeUserSettings();
+}
+
+} // namespace
+
+Step::CoverAnimation::~CoverAnimation() = default;
+
+Step::Step(
+	QWidget *parent,
+	not_null<Main::Account*> account,
+	not_null<Data*> data,
+	bool hasCover)
+: RpWidget(parent)
+, _account(account)
+, _data(data)
+, _hasCover(hasCover)
+, _title(this, _hasCover ? st::introCoverTitle : st::introTitle)
+, _description(
+	this,
+	object_ptr<Ui::FlatLabel>(
+		this,
+		_hasCover
+			? st::introCoverDescription
+			: st::introDescription)) {
+	hide();
+	subscribe(Window::Theme::Background(), [this](
+			const Window::Theme::BackgroundUpdate &update) {
+		if (update.paletteChanged()) {
+			if (!_coverMask.isNull()) {
+				_coverMask = QPixmap();
+				prepareCoverMask();
+			}
+		}
+	});
+
+	_errorText.value(
+	) | rpl::start_with_next([=](const QString &text) {
+		refreshError(text);
+	}, lifetime());
+
+	_titleText.value(
+	) | rpl::start_with_next([=](const QString &text) {
+		_title->setText(text);
+		updateLabelsPosition();
+	}, lifetime());
+
+	_descriptionText.value(
+	) | rpl::start_with_next([=](const TextWithEntities &text) {
+		_description->entity()->setMarkedText(text);
+		updateLabelsPosition();
+	}, lifetime());
+}
+
+Step::~Step() = default;
+
+rpl::producer<QString> Step::nextButtonText() const {
+	return tr::lng_intro_next();
+}
+
+void Step::goBack() {
+	if (_goCallback) {
+		_goCallback(nullptr, Direction::Back);
+	}
+}
+
+void Step::goNext(Step *step) {
+	if (_goCallback) {
+		_goCallback(step, Direction::Forward);
+	}
+}
+
+void Step::goReplace(Step *step) {
+	if (_goCallback) {
+		_goCallback(step, Direction::Replace);
+	}
+}
+
+void Step::finish(const MTPUser &user, QImage &&photo) {
+	if (user.type() != mtpc_user
+		|| !user.c_user().is_self()
+		|| !user.c_user().vid().v) {
+		// No idea what to do here.
+		// We could've reset intro and MTP, but this really should not happen.
+		Ui::show(Box<InformBox>("Internal error: bad user.is_self() after sign in."));
+		return;
+	}
+
+	// Save the default language if we've suggested some other and user ignored it.
+	const auto currentId = Lang::Current().id();
+	const auto defaultId = Lang::DefaultLanguageId();
+	const auto suggested = Lang::CurrentCloudManager().suggestedLanguage();
+	if (currentId.isEmpty() && !suggested.isEmpty() && suggested != defaultId) {
+		Lang::Current().switchToId(Lang::DefaultLanguage());
+		Local::writeLangPack();
+	}
+
+	const auto account = _account;
+	const auto weak = base::make_weak(account.get());
+	account->createSession(user);
+	Local::writeMtpData();
+	App::wnd()->setupMain();
+
+	// "this" is already deleted here by creating the main widget.
+	if (weak && account->sessionExists()) {
+		auto &session = account->session();
+		if (!photo.isNull()) {
+			session.api().uploadPeerPhoto(session.user(), std::move(photo));
+		}
+		if (session.supportMode()) {
+			PrepareSupportMode();
+		}
+	}
+}
+
+void Step::paintEvent(QPaintEvent *e) {
+	Painter p(this);
+	paintAnimated(p, e->rect());
+}
+
+void Step::resizeEvent(QResizeEvent *e) {
+	updateLabelsPosition();
+}
+
+void Step::updateLabelsPosition() {
+	Ui::SendPendingMoveResizeEvents(_description->entity());
+	if (hasCover()) {
+		_title->moveToLeft((width() - _title->width()) / 2, contentTop() + st::introCoverTitleTop);
+		_description->moveToLeft((width() - _description->width()) / 2, contentTop() + st::introCoverDescriptionTop);
+	} else {
+		_title->moveToLeft(contentLeft() + st::buttonRadius, contentTop() + st::introTitleTop);
+		_description->resizeToWidth(st::introDescription.minWidth);
+		_description->moveToLeft(contentLeft() + st::buttonRadius, contentTop() + st::introDescriptionTop);
+	}
+	if (_error) {
+		if (_errorCentered) {
+			_error->entity()->resizeToWidth(width());
+		}
+		Ui::SendPendingMoveResizeEvents(_error->entity());
+		auto errorLeft = _errorCentered ? 0 : (contentLeft() + st::buttonRadius);
+		auto errorTop = contentTop() + (_errorBelowLink ? st::introErrorBelowLinkTop : st::introErrorTop);
+		_error->moveToLeft(errorLeft, errorTop);
+	}
+}
+
+void Step::setTitleText(rpl::producer<QString> titleText) {
+	_titleText = std::move(titleText);
+}
+
+void Step::setDescriptionText(
+		rpl::producer<QString> descriptionText) {
+	setDescriptionText(
+		std::move(descriptionText) | Ui::Text::ToWithEntities());
+}
+
+void Step::setDescriptionText(
+		rpl::producer<TextWithEntities> richDescriptionText) {
+	_descriptionText = std::move(richDescriptionText);
+}
+
+void Step::showFinished() {
+	_a_show.stop();
+	_coverAnimation = CoverAnimation();
+	_slideAnimation.reset();
+	prepareCoverMask();
+	activate();
+}
+
+bool Step::paintAnimated(Painter &p, QRect clip) {
+	if (_slideAnimation) {
+		_slideAnimation->paintFrame(p, (width() - st::introStepWidth) / 2, contentTop(), width());
+		if (!_slideAnimation->animating()) {
+			showFinished();
+			return false;
+		}
+		return true;
+	}
+
+	auto dt = _a_show.value(1.);
+	if (!_a_show.animating()) {
+		if (hasCover()) {
+			paintCover(p, 0);
+		}
+		if (_coverAnimation.title) {
+			showFinished();
+		}
+		if (!QRect(0, contentTop(), width(), st::introStepHeight).intersects(clip)) {
+			return true;
+		}
+		return false;
+	}
+
+	auto progress = (hasCover() ? anim::easeOutCirc(1., dt) : anim::linear(1., dt));
+	auto arrivingAlpha = progress;
+	auto departingAlpha = 1. - progress;
+	auto showCoverMethod = progress;
+	auto hideCoverMethod = progress;
+	auto coverTop = (hasCover() ? anim::interpolate(-st::introCoverHeight, 0, showCoverMethod) : anim::interpolate(0, -st::introCoverHeight, hideCoverMethod));
+
+	paintCover(p, coverTop);
+
+	auto positionReady = hasCover() ? showCoverMethod : hideCoverMethod;
+	_coverAnimation.title->paintFrame(p, positionReady, departingAlpha, arrivingAlpha);
+	_coverAnimation.description->paintFrame(p, positionReady, departingAlpha, arrivingAlpha);
+
+	paintContentSnapshot(p, _coverAnimation.contentSnapshotWas, departingAlpha, showCoverMethod);
+	paintContentSnapshot(p, _coverAnimation.contentSnapshotNow, arrivingAlpha, 1. - hideCoverMethod);
+
+	return true;
+}
+
+void Step::fillSentCodeData(const MTPDauth_sentCode &data) {
+	const auto &type = data.vtype();
+	switch (type.type()) {
+	case mtpc_auth_sentCodeTypeApp: {
+		getData()->codeByTelegram = true;
+		getData()->codeLength = type.c_auth_sentCodeTypeApp().vlength().v;
+	} break;
+	case mtpc_auth_sentCodeTypeSms: {
+		getData()->codeByTelegram = false;
+		getData()->codeLength = type.c_auth_sentCodeTypeSms().vlength().v;
+	} break;
+	case mtpc_auth_sentCodeTypeCall: {
+		getData()->codeByTelegram = false;
+		getData()->codeLength = type.c_auth_sentCodeTypeCall().vlength().v;
+	} break;
+	case mtpc_auth_sentCodeTypeFlashCall: LOG(("Error: should not be flashcall!")); break;
+	}
+}
+
+void Step::showDescription() {
+	_description->show(anim::type::normal);
+}
+
+void Step::hideDescription() {
+	_description->hide(anim::type::normal);
+}
+
+void Step::paintContentSnapshot(Painter &p, const QPixmap &snapshot, float64 alpha, float64 howMuchHidden) {
+	if (!snapshot.isNull()) {
+		auto contentTop = anim::interpolate(height() - (snapshot.height() / cIntRetinaFactor()), height(), howMuchHidden);
+		if (contentTop < height()) {
+			p.setOpacity(alpha);
+			p.drawPixmap(QPoint(contentLeft(), contentTop), snapshot, QRect(0, 0, snapshot.width(), (height() - contentTop) * cIntRetinaFactor()));
+		}
+	}
+}
+
+void Step::prepareCoverMask() {
+	if (!_coverMask.isNull()) return;
+
+	auto maskWidth = cIntRetinaFactor();
+	auto maskHeight = st::introCoverHeight * cIntRetinaFactor();
+	auto mask = QImage(maskWidth, maskHeight, QImage::Format_ARGB32_Premultiplied);
+	auto maskInts = reinterpret_cast<uint32*>(mask.bits());
+	Assert(mask.depth() == (sizeof(uint32) << 3));
+	auto maskIntsPerLineAdded = (mask.bytesPerLine() >> 2) - maskWidth;
+	Assert(maskIntsPerLineAdded >= 0);
+	auto realHeight = static_cast<float64>(maskHeight - 1);
+	for (auto y = 0; y != maskHeight; ++y) {
+		auto color = anim::color(st::introCoverTopBg, st::introCoverBottomBg, y / realHeight);
+		auto colorInt = anim::getPremultiplied(color);
+		for (auto x = 0; x != maskWidth; ++x) {
+			*maskInts++ = colorInt;
+		}
+		maskInts += maskIntsPerLineAdded;
+	}
+	_coverMask = App::pixmapFromImageInPlace(std::move(mask));
+}
+
+void Step::paintCover(Painter &p, int top) {
+	auto coverHeight = top + st::introCoverHeight;
+	if (coverHeight > 0) {
+		p.drawPixmap(QRect(0, 0, width(), coverHeight), _coverMask, QRect(0, -top * cIntRetinaFactor(), _coverMask.width(), coverHeight * cIntRetinaFactor()));
+	}
+
+	auto left = 0;
+	auto right = 0;
+	if (width() < st::introCoverMaxWidth) {
+		auto iconsMaxSkip = st::introCoverMaxWidth - st::introCoverLeft.width() - st::introCoverRight.width();
+		auto iconsSkip = st::introCoverIconsMinSkip + (iconsMaxSkip - st::introCoverIconsMinSkip) * (width() - st::introStepWidth) / (st::introCoverMaxWidth - st::introStepWidth);
+		auto outside = iconsSkip + st::introCoverLeft.width() + st::introCoverRight.width() - width();
+		left = -outside / 2;
+		right = -outside - left;
+	}
+	if (top < 0) {
+		auto shown = float64(coverHeight) / st::introCoverHeight;
+		auto leftShown = qRound(shown * (left + st::introCoverLeft.width()));
+		left = leftShown - st::introCoverLeft.width();
+		auto rightShown = qRound(shown * (right + st::introCoverRight.width()));
+		right = rightShown - st::introCoverRight.width();
+	}
+	st::introCoverLeft.paint(p, left, coverHeight - st::introCoverLeft.height(), width());
+	st::introCoverRight.paint(p, width() - right - st::introCoverRight.width(), coverHeight - st::introCoverRight.height(), width());
+
+	auto planeLeft = (width() - st::introCoverIcon.width()) / 2 - st::introCoverIconLeft;
+	auto planeTop = top + st::introCoverIconTop;
+	if (top < 0 && !_hasCover) {
+		auto deltaLeft = -qRound(float64(st::introPlaneWidth / st::introPlaneHeight) * top);
+//		auto deltaTop = top;
+		planeLeft += deltaLeft;
+	//	planeTop += top;
+	}
+	st::introCoverIcon.paint(p, planeLeft, planeTop, width());
+}
+
+int Step::contentLeft() const {
+	return (width() - st::introNextButton.width) / 2;
+}
+
+int Step::contentTop() const {
+	auto result = (height() - st::introHeight) / 2;
+	accumulate_max(result, st::introStepTopMin);
+	if (_hasCover) {
+		auto added = 1. - snap(float64(height() - st::windowMinHeight) / (st::introStepHeightFull - st::windowMinHeight), 0., 1.);
+		result += qRound(added * st::introContentTopAdd);
+	}
+	return result;
+}
+
+void Step::setErrorCentered(bool centered) {
+	_errorCentered = centered;
+	_error.destroy();
+}
+
+void Step::setErrorBelowLink(bool below) {
+	_errorBelowLink = below;
+	if (_error) {
+		updateLabelsPosition();
+	}
+}
+
+void Step::showError(rpl::producer<QString> text) {
+	_errorText = std::move(text);
+}
+
+void Step::refreshError(const QString &text) {
+	if (text.isEmpty()) {
+		if (_error) _error->hide(anim::type::normal);
+	} else {
+		if (!_error) {
+			_error.create(
+				this,
+				object_ptr<Ui::FlatLabel>(
+					this,
+					_errorCentered
+						? st::introErrorCentered
+						: st::introError));
+			_error->hide(anim::type::instant);
+		}
+		_error->entity()->setText(text);
+		updateLabelsPosition();
+		_error->show(anim::type::normal);
+	}
+}
+
+void Step::prepareShowAnimated(Step *after) {
+	setInnerFocus();
+	if (hasCover() || after->hasCover()) {
+		_coverAnimation = prepareCoverAnimation(after);
+		prepareCoverMask();
+	} else {
+		auto leftSnapshot = after->prepareSlideAnimation();
+		auto rightSnapshot = prepareSlideAnimation();
+		_slideAnimation = std::make_unique<Ui::SlideAnimation>();
+		_slideAnimation->setSnapshots(std::move(leftSnapshot), std::move(rightSnapshot));
+		_slideAnimation->setOverflowHidden(false);
+	}
+}
+
+Step::CoverAnimation Step::prepareCoverAnimation(Step *after) {
+	auto result = CoverAnimation();
+	result.title = Ui::FlatLabel::CrossFade(
+		after->_title,
+		_title,
+		st::introBg);
+	result.description = Ui::FlatLabel::CrossFade(
+		after->_description->entity(),
+		_description->entity(),
+		st::introBg,
+		after->_description->pos(),
+		_description->pos());
+	result.contentSnapshotWas = after->prepareContentSnapshot();
+	result.contentSnapshotNow = prepareContentSnapshot();
+	return result;
+}
+
+QPixmap Step::prepareContentSnapshot() {
+	auto otherTop = _description->y() + _description->height();
+	auto otherRect = myrtlrect(contentLeft(), otherTop, st::introStepWidth, height() - otherTop);
+	return Ui::GrabWidget(this, otherRect);
+}
+
+QPixmap Step::prepareSlideAnimation() {
+	auto grabLeft = (width() - st::introStepWidth) / 2;
+	auto grabTop = contentTop();
+	return Ui::GrabWidget(
+		this,
+		QRect(grabLeft, grabTop, st::introStepWidth, st::introStepHeight));
+}
+
+void Step::showAnimated(Direction direction) {
+	setFocus();
+	show();
+	hideChildren();
+	if (_slideAnimation) {
+		auto slideLeft = (direction == Direction::Back);
+		_slideAnimation->start(
+			slideLeft,
+			[=] { update(0, contentTop(), width(), st::introStepHeight); },
+			st::introSlideDuration);
+	} else {
+		_a_show.start([this] { update(); }, 0., 1., st::introCoverDuration);
+	}
+}
+
+void Step::setGoCallback(Fn<void(Step *step, Direction direction)> callback) {
+	_goCallback = std::move(callback);
+}
+
+void Step::setShowResetCallback(Fn<void()> callback) {
+	_showResetCallback = std::move(callback);
+}
+
+void Step::setShowTermsCallback(Fn<void()> callback) {
+	_showTermsCallback = std::move(callback);
+}
+
+void Step::setAcceptTermsCallback(
+		Fn<void(Fn<void()> callback)> callback) {
+	_acceptTermsCallback = std::move(callback);
+}
+
+void Step::showFast() {
+	show();
+	showFinished();
+}
+
+bool Step::animating() const {
+	return (_slideAnimation && _slideAnimation->animating()) || _a_show.animating();
+}
+
+bool Step::hasCover() const {
+	return _hasCover;
+}
+
+bool Step::hasBack() const {
+	return false;
+}
+
+void Step::activate() {
+	_title->show();
+	_description->show(anim::type::instant);
+	if (!_errorText.current().isEmpty()) {
+		_error->show(anim::type::instant);
+	}
+}
+
+void Step::cancelled() {
+}
+
+void Step::finished() {
+	hide();
+}
+
+} // namespace details
+} // namespace Intro
diff --git a/Telegram/SourceFiles/intro/intro_step.h b/Telegram/SourceFiles/intro/intro_step.h
new file mode 100644
index 000000000..81ed97259
--- /dev/null
+++ b/Telegram/SourceFiles/intro/intro_step.h
@@ -0,0 +1,192 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/object_ptr.h"
+#include "mtproto/sender.h"
+#include "ui/rp_widget.h"
+#include "ui/effects/animations.h"
+
+namespace Main {
+class Account;
+} // namespace Main;
+
+namespace Ui {
+class SlideAnimation;
+class CrossFadeAnimation;
+class FlatLabel;
+template <typename Widget>
+class FadeWrap;
+} // namespace Ui
+
+namespace Intro {
+namespace details {
+
+struct Data;
+enum class Direction;
+
+class Step
+	: public Ui::RpWidget
+	, public RPCSender
+	, protected base::Subscriber {
+public:
+	Step(
+		QWidget *parent,
+		not_null<Main::Account*> account,
+		not_null<Data*> data,
+		bool hasCover = false);
+	~Step();
+
+	[[nodiscard]] Main::Account &account() const {
+		return *_account;
+	}
+
+	virtual void finishInit() {
+	}
+	virtual void setInnerFocus() {
+		setFocus();
+	}
+
+	void setGoCallback(
+		Fn<void(Step *step, Direction direction)> callback);
+	void setShowResetCallback(Fn<void()> callback);
+	void setShowTermsCallback(
+		Fn<void()> callback);
+	void setAcceptTermsCallback(
+		Fn<void(Fn<void()> callback)> callback);
+
+	void prepareShowAnimated(Step *after);
+	void showAnimated(Direction direction);
+	void showFast();
+	[[nodiscard]] bool animating() const;
+
+	[[nodiscard]] bool hasCover() const;
+	[[nodiscard]] virtual bool hasBack() const;
+	virtual void activate();
+	virtual void cancelled();
+	virtual void finished();
+
+	virtual void submit() = 0;
+	[[nodiscard]] virtual rpl::producer<QString> nextButtonText() const;
+
+	[[nodiscard]] int contentLeft() const;
+	[[nodiscard]] int contentTop() const;
+
+	void setErrorCentered(bool centered);
+	void setErrorBelowLink(bool below);
+	void showError(rpl::producer<QString> text);
+	void hideError() {
+		showError(rpl::single(QString()));
+	}
+
+protected:
+	void paintEvent(QPaintEvent *e) override;
+	void resizeEvent(QResizeEvent *e) override;
+
+	void setTitleText(rpl::producer<QString> titleText);
+	void setDescriptionText(rpl::producer<QString> descriptionText);
+	void setDescriptionText(
+		rpl::producer<TextWithEntities> richDescriptionText);
+	bool paintAnimated(Painter &p, QRect clip);
+
+	void fillSentCodeData(const MTPDauth_sentCode &type);
+
+	void showDescription();
+	void hideDescription();
+
+	[[nodiscard]] not_null<Data*> getData() const {
+		return _data;
+	}
+	void finish(const MTPUser &user, QImage &&photo = QImage());
+
+	void goBack();
+
+	template <typename StepType>
+	void goNext() {
+		goNext(new StepType(parentWidget(), _account, _data));
+	}
+
+	template <typename StepType>
+	void goReplace() {
+		goReplace(new StepType(parentWidget(), _account, _data));
+	}
+
+	void showResetButton() {
+		if (_showResetCallback) _showResetCallback();
+	}
+	void showTerms() {
+		if (_showTermsCallback) _showTermsCallback();
+	}
+	void acceptTerms(Fn<void()> callback) {
+		if (_acceptTermsCallback) {
+			_acceptTermsCallback(callback);
+		}
+	}
+
+private:
+	struct CoverAnimation {
+		CoverAnimation() = default;
+		CoverAnimation(CoverAnimation &&other) = default;
+		CoverAnimation &operator=(CoverAnimation &&other) = default;
+		~CoverAnimation();
+
+		std::unique_ptr<Ui::CrossFadeAnimation> title;
+		std::unique_ptr<Ui::CrossFadeAnimation> description;
+
+		// From content top till the next button top.
+		QPixmap contentSnapshotWas;
+		QPixmap contentSnapshotNow;
+	};
+	void updateLabelsPosition();
+	void paintContentSnapshot(
+		Painter &p,
+		const QPixmap &snapshot,
+		float64 alpha,
+		float64 howMuchHidden);
+	void refreshError(const QString &text);
+
+	void goNext(Step *step);
+	void goReplace(Step *step);
+
+	[[nodiscard]] CoverAnimation prepareCoverAnimation(Step *step);
+	[[nodiscard]] QPixmap prepareContentSnapshot();
+	[[nodiscard]] QPixmap prepareSlideAnimation();
+	void showFinished();
+
+	void prepareCoverMask();
+	void paintCover(Painter &p, int top);
+
+	const not_null<Main::Account*> _account;
+	const not_null<Data*> _data;
+
+	bool _hasCover = false;
+	Fn<void(Step *step, Direction direction)> _goCallback;
+	Fn<void()> _showResetCallback;
+	Fn<void()> _showTermsCallback;
+	Fn<void(Fn<void()> callback)> _acceptTermsCallback;
+
+	rpl::variable<QString> _titleText;
+	object_ptr<Ui::FlatLabel> _title;
+	rpl::variable<TextWithEntities> _descriptionText;
+	object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _description;
+
+	bool _errorCentered = false;
+	bool _errorBelowLink = false;
+	rpl::variable<QString> _errorText;
+	object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _error = { nullptr };
+
+	Ui::Animations::Simple _a_show;
+	CoverAnimation _coverAnimation;
+	std::unique_ptr<Ui::SlideAnimation> _slideAnimation;
+	QPixmap _coverMask;
+
+};
+
+
+} // namespace details
+} // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introcode.cpp b/Telegram/SourceFiles/intro/introcode.cpp
index 32eee158b..d8d6fce51 100644
--- a/Telegram/SourceFiles/intro/introcode.cpp
+++ b/Telegram/SourceFiles/intro/introcode.cpp
@@ -19,6 +19,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "styles/style_intro.h"
 
 namespace Intro {
+namespace details {
 
 CodeInput::CodeInput(
 	QWidget *parent,
@@ -77,7 +78,7 @@ void CodeInput::correctValue(const QString &was, int wasCursor, QString &now, in
 CodeWidget::CodeWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
-	not_null<Widget::Data*> data)
+	not_null<Data*> data)
 : Step(parent, account, data)
 , _noTelegramCode(this, tr::lng_code_no_telegram(tr::now), st::introLink)
 , _code(this, st::introCode, tr::lng_code_ph())
@@ -118,7 +119,7 @@ void CodeWidget::updateDescText() {
 		_noTelegramCode->hide();
 		_callStatus = getData()->callStatus;
 		_callTimeout = getData()->callTimeout;
-		if (_callStatus == Widget::Data::CallStatus::Waiting && !_callTimer->isActive()) {
+		if (_callStatus == CallStatus::Waiting && !_callTimer->isActive()) {
 			_callTimer->start(1000);
 		}
 	}
@@ -131,7 +132,7 @@ void CodeWidget::updateCallText() {
 			return QString();
 		}
 		switch (_callStatus) {
-		case Widget::Data::CallStatus::Waiting: {
+		case CallStatus::Waiting: {
 			if (_callTimeout >= 3600) {
 				return tr::lng_code_call(
 					tr::now,
@@ -150,9 +151,9 @@ void CodeWidget::updateCallText() {
 					qsl("%1").arg(_callTimeout % 60, 2, 10, QChar('0')));
 			}
 		} break;
-		case Widget::Data::CallStatus::Calling:
+		case CallStatus::Calling:
 			return tr::lng_code_calling(tr::now);
-		case Widget::Data::CallStatus::Called:
+		case CallStatus::Called:
 			return tr::lng_code_called(tr::now);
 		}
 		return QString();
@@ -295,9 +296,9 @@ void CodeWidget::onInputChange() {
 }
 
 void CodeWidget::onSendCall() {
-	if (_callStatus == Widget::Data::CallStatus::Waiting) {
+	if (_callStatus == CallStatus::Waiting) {
 		if (--_callTimeout <= 0) {
-			_callStatus = Widget::Data::CallStatus::Calling;
+			_callStatus = CallStatus::Calling;
 			_callTimer->stop();
 			_callRequestId = MTP::send(MTPauth_ResendCode(MTP_string(getData()->phone), MTP_bytes(getData()->phoneHash)), rpcDone(&CodeWidget::callDone));
 		} else {
@@ -313,8 +314,8 @@ void CodeWidget::callDone(const MTPauth_SentCode &v) {
 		fillSentCodeData(v.c_auth_sentCode());
 		_code->setDigitsCountMax(getData()->codeLength);
 	}
-	if (_callStatus == Widget::Data::CallStatus::Calling) {
-		_callStatus = Widget::Data::CallStatus::Called;
+	if (_callStatus == CallStatus::Calling) {
+		_callStatus = CallStatus::Called;
 		getData()->callStatus = _callStatus;
 		getData()->callTimeout = _callTimeout;
 		updateCallText();
@@ -406,10 +407,10 @@ void CodeWidget::noTelegramCodeDone(const MTPauth_SentCode &result) {
 	_code->setDigitsCountMax(getData()->codeLength);
 	const auto next = d.vnext_type();
 	if (next && next->type() == mtpc_auth_codeTypeCall) {
-		getData()->callStatus = Widget::Data::CallStatus::Waiting;
+		getData()->callStatus = CallStatus::Waiting;
 		getData()->callTimeout = d.vtimeout().value_or(60);
 	} else {
-		getData()->callStatus = Widget::Data::CallStatus::Disabled;
+		getData()->callStatus = CallStatus::Disabled;
 		getData()->callTimeout = 0;
 	}
 	getData()->codeByTelegram = false;
@@ -435,4 +436,5 @@ bool CodeWidget::noTelegramCodeFail(const RPCError &error) {
 	return false;
 }
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introcode.h b/Telegram/SourceFiles/intro/introcode.h
index 527715035..5aaaeb352 100644
--- a/Telegram/SourceFiles/intro/introcode.h
+++ b/Telegram/SourceFiles/intro/introcode.h
@@ -7,8 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "intro/introwidget.h"
+#include "intro/intro_step.h"
 #include "ui/widgets/input_fields.h"
+#include "intro/introwidget.h"
 
 namespace Ui {
 class RoundButton;
@@ -17,6 +18,9 @@ class FlatLabel;
 } // namespace Ui
 
 namespace Intro {
+namespace details {
+
+enum class CallStatus;
 
 class CodeInput final : public Ui::MaskedInputField {
 public:
@@ -35,14 +39,14 @@ private:
 
 };
 
-class CodeWidget : public Widget::Step {
+class CodeWidget : public Step {
 	Q_OBJECT
 
 public:
 	CodeWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
-		not_null<Widget::Data*> data);
+		not_null<Data*> data);
 
 	bool hasBack() const override {
 		return true;
@@ -89,7 +93,7 @@ private:
 	mtpRequestId _sentRequest = 0;
 
 	object_ptr<QTimer> _callTimer;
-	Widget::Data::CallStatus _callStatus;
+	CallStatus _callStatus = CallStatus();
 	int _callTimeout;
 	mtpRequestId _callRequestId = 0;
 	object_ptr<Ui::FlatLabel> _callLabel;
@@ -98,4 +102,5 @@ private:
 
 };
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introphone.cpp b/Telegram/SourceFiles/intro/introphone.cpp
index ea838a170..e6bee5332 100644
--- a/Telegram/SourceFiles/intro/introphone.cpp
+++ b/Telegram/SourceFiles/intro/introphone.cpp
@@ -20,6 +20,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/application.h"
 
 namespace Intro {
+namespace details {
 namespace {
 
 bool AllowPhoneAttempt(const QString &phone) {
@@ -34,7 +35,7 @@ bool AllowPhoneAttempt(const QString &phone) {
 PhoneWidget::PhoneWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
-	not_null<Widget::Data*> data)
+	not_null<Data*> data)
 : Step(parent, account, data)
 , _country(this, st::introCountry)
 , _code(this, st::introCountryCode)
@@ -52,7 +53,7 @@ PhoneWidget::PhoneWidget(
 
 	setTitleText(tr::lng_phone_title());
 	setDescriptionText(tr::lng_phone_desc());
-	subscribe(getData()->updated, [this] { countryChanged(); });
+	subscribe(getData()->updated, [=] { countryChanged(); });
 	setErrorCentered(true);
 
 	if (!_country->onChooseCountry(getData()->country)) {
@@ -149,10 +150,10 @@ void PhoneWidget::phoneSubmitDone(const MTPauth_SentCode &result) {
 	getData()->phoneHash = qba(d.vphone_code_hash());
 	const auto next = d.vnext_type();
 	if (next && next->type() == mtpc_auth_codeTypeCall) {
-		getData()->callStatus = Widget::Data::CallStatus::Waiting;
+		getData()->callStatus = CallStatus::Waiting;
 		getData()->callTimeout = d.vtimeout().value_or(60);
 	} else {
-		getData()->callStatus = Widget::Data::CallStatus::Disabled;
+		getData()->callStatus = CallStatus::Disabled;
 		getData()->callTimeout = 0;
 	}
 	goNext<CodeWidget>();
@@ -220,4 +221,5 @@ void PhoneWidget::cancelled() {
 	MTP::cancel(base::take(_sentRequest));
 }
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introphone.h b/Telegram/SourceFiles/intro/introphone.h
index 71316cdfe..17ce9abce 100644
--- a/Telegram/SourceFiles/intro/introphone.h
+++ b/Telegram/SourceFiles/intro/introphone.h
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "ui/countryinput.h"
-#include "intro/introwidget.h"
+#include "intro/intro_step.h"
 
 namespace Ui {
 class PhonePartInput;
@@ -18,15 +18,16 @@ class FlatLabel;
 } // namespace Ui
 
 namespace Intro {
+namespace details {
 
-class PhoneWidget : public Widget::Step {
+class PhoneWidget : public Step {
 	Q_OBJECT
 
 public:
 	PhoneWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
-		not_null<Widget::Data*> data);
+		not_null<Data*> data);
 
 	void selectCountry(const QString &country);
 
@@ -72,4 +73,5 @@ private:
 
 };
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.cpp b/Telegram/SourceFiles/intro/intropwdcheck.cpp
index b8d31d8ab..db2e807b2 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.cpp
+++ b/Telegram/SourceFiles/intro/intropwdcheck.cpp
@@ -7,8 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "intro/intropwdcheck.h"
 
-#include "styles/style_intro.h"
-#include "styles/style_boxes.h"
+#include "intro/introwidget.h"
 #include "core/file_utilities.h"
 #include "core/core_cloud_password.h"
 #include "boxes/confirm_box.h"
@@ -18,13 +17,16 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/input_fields.h"
 #include "ui/widgets/labels.h"
 #include "base/openssl_help.h"
+#include "styles/style_intro.h"
+#include "styles/style_boxes.h"
 
 namespace Intro {
+namespace details {
 
 PwdCheckWidget::PwdCheckWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
-	not_null<Widget::Data*> data)
+	not_null<Data*> data)
 : Step(parent, account, data)
 , _request(getData()->pwdRequest)
 , _hasRecovery(getData()->hasRecovery)
@@ -389,4 +391,5 @@ rpl::producer<QString> PwdCheckWidget::nextButtonText() const {
 	return tr::lng_intro_submit();
 }
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.h b/Telegram/SourceFiles/intro/intropwdcheck.h
index a0fc7b555..5113781b5 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.h
+++ b/Telegram/SourceFiles/intro/intropwdcheck.h
@@ -7,7 +7,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "intro/introwidget.h"
+#include "intro/intro_step.h"
+#include "core/core_cloud_password.h"
 #include "mtproto/sender.h"
 
 namespace Ui {
@@ -18,15 +19,16 @@ class LinkButton;
 } // namespace Ui
 
 namespace Intro {
+namespace details {
 
-class PwdCheckWidget : public Widget::Step, private MTP::Sender {
+class PwdCheckWidget : public Step, private MTP::Sender {
 	Q_OBJECT
 
 public:
 	PwdCheckWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
-		not_null<Widget::Data*> data);
+		not_null<Data*> data);
 
 	void setInnerFocus() override;
 	void activate() override;
@@ -81,4 +83,5 @@ private:
 
 };
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introsignup.cpp b/Telegram/SourceFiles/intro/introsignup.cpp
index 01d71d369..9594820b9 100644
--- a/Telegram/SourceFiles/intro/introsignup.cpp
+++ b/Telegram/SourceFiles/intro/introsignup.cpp
@@ -7,8 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "intro/introsignup.h"
 
-#include "styles/style_intro.h"
-#include "styles/style_boxes.h"
+#include "intro/introwidget.h"
 #include "core/file_utilities.h"
 #include "boxes/photo_crop_box.h"
 #include "boxes/confirm_box.h"
@@ -17,23 +16,26 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/input_fields.h"
 #include "ui/widgets/labels.h"
 #include "ui/special_buttons.h"
+#include "styles/style_intro.h"
+#include "styles/style_boxes.h"
 
 namespace Intro {
+namespace details {
 
 SignupWidget::SignupWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
-	not_null<Widget::Data*> data)
-: Step(parent, account, data)
-, _photo(
-	this,
-	tr::lng_settings_crop_profile(tr::now),
-	Ui::UserpicButton::Role::ChangePhoto,
-	st::defaultUserpicButton)
-, _first(this, st::introName, tr::lng_signup_firstname())
-, _last(this, st::introName, tr::lng_signup_lastname())
-, _invertOrder(langFirstNameGoesSecond())
-, _checkRequest(this) {
+	not_null<Data*> data)
+	: Step(parent, account, data)
+	, _photo(
+		this,
+		tr::lng_settings_crop_profile(tr::now),
+		Ui::UserpicButton::Role::ChangePhoto,
+		st::defaultUserpicButton)
+	, _first(this, st::introName, tr::lng_signup_firstname())
+	, _last(this, st::introName, tr::lng_signup_lastname())
+	, _invertOrder(langFirstNameGoesSecond())
+	, _checkRequest(this) {
 	subscribe(Lang::Current().updated(), [this] { refreshLang(); });
 	if (_invertOrder) {
 		setTabOrder(_last, _first);
@@ -236,4 +238,5 @@ rpl::producer<QString> SignupWidget::nextButtonText() const {
 	return tr::lng_intro_finish();
 }
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introsignup.h b/Telegram/SourceFiles/intro/introsignup.h
index 7eadd5ae8..f9969d6d4 100644
--- a/Telegram/SourceFiles/intro/introsignup.h
+++ b/Telegram/SourceFiles/intro/introsignup.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "intro/introwidget.h"
+#include "intro/intro_step.h"
 
 namespace Ui {
 class RoundButton;
@@ -16,15 +16,16 @@ class UserpicButton;
 } // namespace Ui
 
 namespace Intro {
+namespace details {
 
-class SignupWidget : public Widget::Step {
+class SignupWidget : public Step {
 	Q_OBJECT
 
 public:
 	SignupWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
-		not_null<Widget::Data*> data);
+		not_null<Data*> data);
 
 	void finishInit() override;
 	void setInnerFocus() override;
@@ -62,4 +63,5 @@ private:
 
 };
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introstart.cpp b/Telegram/SourceFiles/intro/introstart.cpp
index cd70a996e..e5aab0612 100644
--- a/Telegram/SourceFiles/intro/introstart.cpp
+++ b/Telegram/SourceFiles/intro/introstart.cpp
@@ -13,11 +13,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/labels.h"
 
 namespace Intro {
+namespace details {
 
 StartWidget::StartWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
-	not_null<Widget::Data*> data)
+	not_null<Data*> data)
 : Step(parent, account, data, true) {
 	setMouseTracking(true);
 	setTitleText(rpl::single(qsl("Telegram Desktop")));
@@ -33,4 +34,5 @@ rpl::producer<QString> StartWidget::nextButtonText() const {
 	return tr::lng_start_msgs();
 }
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introstart.h b/Telegram/SourceFiles/intro/introstart.h
index 9f7048f6f..4b3f072cd 100644
--- a/Telegram/SourceFiles/intro/introstart.h
+++ b/Telegram/SourceFiles/intro/introstart.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "intro/introwidget.h"
+#include "intro/intro_step.h"
 
 namespace Ui {
 class FlatLabel;
@@ -16,17 +16,19 @@ class RoundButton;
 } // namespace Ui
 
 namespace Intro {
+namespace details {
 
-class StartWidget : public Widget::Step {
+class StartWidget : public Step {
 public:
 	StartWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
-		not_null<Widget::Data*> data);
+		not_null<Data*> data);
 
 	void submit() override;
 	rpl::producer<QString> nextButtonText() const override;
 
 };
 
+} // namespace details
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introwidget.cpp b/Telegram/SourceFiles/intro/introwidget.cpp
index 6ffe8b060..c183069f6 100644
--- a/Telegram/SourceFiles/intro/introwidget.cpp
+++ b/Telegram/SourceFiles/intro/introwidget.cpp
@@ -7,55 +7,34 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "intro/introwidget.h"
 
-#include "lang/lang_keys.h"
-#include "lang/lang_file_parser.h"
-#include "storage/localstorage.h"
 #include "intro/introstart.h"
 #include "intro/introphone.h"
 #include "intro/introcode.h"
 #include "intro/introsignup.h"
 #include "intro/intropwdcheck.h"
+#include "lang/lang_keys.h"
+#include "lang/lang_cloud_manager.h"
+#include "storage/localstorage.h"
 #include "main/main_account.h"
-#include "mainwidget.h"
-#include "apiwrap.h"
 #include "mainwindow.h"
-#include "core/application.h"
 #include "boxes/confirm_box.h"
-#include "ui/text/text.h"
 #include "ui/text/text_utilities.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
 #include "ui/wrap/fade_wrap.h"
-#include "ui/effects/slide_animation.h"
 #include "core/update_checker.h"
 #include "window/window_slide_animation.h"
 #include "window/window_connecting_widget.h"
-#include "window/window_lock_widgets.h"
 #include "base/platform/base_platform_info.h"
-#include "data/data_user.h"
-#include "window/themes/window_theme.h"
-#include "lang/lang_cloud_manager.h"
-#include "main/main_session.h"
 #include "facades.h"
 #include "app.h"
 #include "styles/style_layers.h"
 #include "styles/style_intro.h"
-#include "styles/style_window.h"
 
 namespace Intro {
 namespace {
 
-void PrepareSupportMode() {
-	using Data::AutoDownload::Full;
-
-	anim::SetDisabled(true);
-	Local::writeSettings();
-
-	Global::SetDesktopNotify(false);
-	Global::SetSoundNotify(false);
-	Auth().settings().autoDownload() = Full::FullDisabled();
-	Local::writeUserSettings();
-}
+using namespace ::Intro::details;
 
 } // namespace
 
@@ -72,7 +51,9 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 , _next(this, nullptr, st::introNextButton) {
 	getData()->country = Platform::SystemCountry();
 
-	_back->entity()->setClickedCallback([this] { historyMove(Direction::Back); });
+	_back->entity()->setClickedCallback([=] {
+		historyMove(Direction::Back);
+	});
 	_back->hide(anim::type::instant);
 
 	_next->setClickedCallback([this] { getStep()->submit(); });
@@ -100,17 +81,15 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 
 	if (!Core::UpdaterDisabled()) {
 		Core::UpdateChecker checker;
-		checker.isLatest() | rpl::start_with_next([=] {
-			onCheckUpdateStatus();
-		}, lifetime());
-		checker.failed() | rpl::start_with_next([=] {
-			onCheckUpdateStatus();
-		}, lifetime());
-		checker.ready() | rpl::start_with_next([=] {
-			onCheckUpdateStatus();
-		}, lifetime());
 		checker.start();
-		onCheckUpdateStatus();
+		rpl::merge(
+			rpl::single(rpl::empty_value()),
+			checker.isLatest(),
+			checker.failed(),
+			checker.ready()
+		) | rpl::start_with_next([=] {
+			checkUpdateStatus();
+		}, lifetime());
 	}
 }
 
@@ -165,7 +144,7 @@ void Widget::createLanguageLink() {
 	}
 }
 
-void Widget::onCheckUpdateStatus() {
+void Widget::checkUpdateStatus() {
 	Expects(!Core::UpdaterDisabled());
 
 	if (Core::UpdateChecker().state() == Core::UpdateChecker::State::Ready) {
@@ -201,16 +180,18 @@ void Widget::setInnerFocus() {
 }
 
 void Widget::historyMove(Direction direction) {
-	if (getStep()->animating()) return;
+	Expects(_stepHistory.size() > 1);
 
-	Assert(_stepHistory.size() > 1);
+	if (getStep()->animating()) {
+		return;
+	}
 
 	auto wasStep = getStep((direction == Direction::Back) ? 0 : 1);
 	if (direction == Direction::Back) {
 		_stepHistory.pop_back();
 		wasStep->cancelled();
 	} else if (direction == Direction::Replace) {
-		_stepHistory.removeAt(_stepHistory.size() - 2);
+		_stepHistory.erase(_stepHistory.end() - 2);
 	}
 
 	if (_resetAccount) {
@@ -223,7 +204,7 @@ void Widget::historyMove(Direction direction) {
 	getStep()->finishInit();
 	getStep()->prepareShowAnimated(wasStep);
 	if (wasStep->hasCover() != getStep()->hasCover()) {
-		_nextTopFrom = wasStep->contentTop() + st::introStepHeight;
+		_nextTopFrom = wasStep->contentTop() + st::introNextTop;
 		_controlsTopFrom = wasStep->hasCover() ? st::introCoverHeight : 0;
 		_coverShownAnimation.start([this] { updateControlsGeometry(); }, 0., 1., st::introCoverDuration, wasStep->hasCover() ? anim::linear : anim::easeOutCirc);
 	}
@@ -241,7 +222,7 @@ void Widget::historyMove(Direction direction) {
 	if (_update) {
 		_update->toggle(!stepHasCover, anim::type::normal);
 	}
-	_next->setText(getStep()->nextButtonText());
+	setupNextButton();
 	if (_resetAccount) _resetAccount->show(anim::type::normal);
 	if (_terms) _terms->show(anim::type::normal);
 	if (_changeLanguage) {
@@ -286,7 +267,7 @@ void Widget::moveToStep(Step *step, Direction direction) {
 
 void Widget::appendStep(Step *step) {
 	_stepHistory.push_back(step);
-	step->setGeometry(calculateStepRect());
+	step->setGeometry(rect());
 	step->setGoCallback([=](Step *step, Direction direction) {
 		if (direction == Direction::Back) {
 			historyMove(direction);
@@ -495,7 +476,8 @@ void Widget::showTerms(Fn<void()> callback) {
 void Widget::showControls() {
 	getStep()->show();
 	_next->show();
-	_next->setText(getStep()->nextButtonText());
+	setupNextButton();
+	_nextShownAnimation.stop();
 	_connecting->setForceHidden(false);
 	auto hasCover = getStep()->hasCover();
 	_settings->toggle(!hasCover, anim::type::instant);
@@ -513,6 +495,27 @@ void Widget::showControls() {
 	_back->toggle(getStep()->hasBack(), anim::type::instant);
 }
 
+void Widget::setupNextButton() {
+	_next->setText(getStep()->nextButtonText(
+	) | rpl::filter([](const QString &text) {
+		return !text.isEmpty();
+	}));
+	auto visible = getStep()->nextButtonText(
+	) | rpl::map([](const QString &text) {
+		return !text.isEmpty();
+	}) | rpl::distinct_until_changed();
+	std::move(
+		visible
+	) | rpl::start_with_next([=](bool visible) {
+		_nextShown = visible;
+		_nextShownAnimation.start(
+			[=] { updateControlsGeometry(); },
+			_nextShown ? 0. : 1.,
+			_nextShown ? 1. : 0.,
+			st::slideDuration);
+	}, getStep()->lifetime());
+}
+
 void Widget::hideControls() {
 	getStep()->hide();
 	_next->hide();
@@ -534,7 +537,12 @@ void Widget::showAnimated(const QPixmap &bgAnimCache, bool back) {
 	(_showBack ? _cacheUnder : _cacheOver) = Ui::GrabWidget(this);
 	hideControls();
 
-	_a_show.start([=] { animationCallback(); }, 0., 1., st::slideDuration, Window::SlideAnimation::transition());
+	_a_show.start(
+		[=] { animationCallback(); },
+		0.,
+		1.,
+		st::slideDuration,
+		Window::SlideAnimation::transition());
 
 	show();
 }
@@ -575,20 +583,9 @@ void Widget::paintEvent(QPaintEvent *e) {
 	}
 }
 
-QRect Widget::calculateStepRect() const {
-	auto stepInnerTop = (height() - st::introHeight) / 2;
-	accumulate_max(stepInnerTop, st::introStepTopMin);
-	auto nextTop = stepInnerTop + st::introStepHeight;
-	auto additionalHeight = st::introStepHeightAdd;
-	auto stepWidth = width();
-	auto stepHeight = nextTop + additionalHeight;
-	return QRect(0, 0, stepWidth, stepHeight);
-}
-
 void Widget::resizeEvent(QResizeEvent *e) {
-	auto stepRect = calculateStepRect();
-	for_const (auto step, _stepHistory) {
-		step->setGeometry(stepRect);
+	for (const auto step : _stepHistory) {
+		step->setGeometry(rect());
 	}
 
 	updateControlsGeometry();
@@ -605,9 +602,11 @@ void Widget::updateControlsGeometry() {
 	}
 	_back->moveToLeft(0, controlsTop);
 
-	auto nextTopTo = getStep()->contentTop() + st::introStepHeight;
+	auto nextTopTo = getStep()->contentTop() + st::introNextTop;
 	auto nextTop = anim::interpolate(_nextTopFrom, nextTopTo, shown);
-	_next->moveToLeft((width() - _next->width()) / 2, nextTop);
+	const auto shownAmount = _nextShownAnimation.value(_nextShown ? 1. : 0.);
+	const auto realNextTop = anim::interpolate(height(), nextTop, shownAmount);
+	_next->moveToLeft((width() - _next->width()) / 2, realNextTop);
 	if (_changeLanguage) {
 		_changeLanguage->moveToLeft((width() - _changeLanguage->width()) / 2, _next->y() + _next->height() + _changeLanguage->height());
 	}
@@ -641,441 +640,4 @@ Widget::~Widget() {
 	if (App::wnd()) App::wnd()->noIntro(this);
 }
 
-rpl::producer<QString> Widget::Step::nextButtonText() const {
-	return tr::lng_intro_next();
-}
-
-void Widget::Step::finish(const MTPUser &user, QImage &&photo) {
-	if (user.type() != mtpc_user
-		|| !user.c_user().is_self()
-		|| !user.c_user().vid().v) {
-		// No idea what to do here.
-		// We could've reset intro and MTP, but this really should not happen.
-		Ui::show(Box<InformBox>("Internal error: bad user.is_self() after sign in."));
-		return;
-	}
-
-	// Save the default language if we've suggested some other and user ignored it.
-	const auto currentId = Lang::Current().id();
-	const auto defaultId = Lang::DefaultLanguageId();
-	const auto suggested = Lang::CurrentCloudManager().suggestedLanguage();
-	if (currentId.isEmpty() && !suggested.isEmpty() && suggested != defaultId) {
-		Lang::Current().switchToId(Lang::DefaultLanguage());
-		Local::writeLangPack();
-	}
-
-	const auto account = _account;
-	const auto weak = base::make_weak(account.get());
-	account->createSession(user);
-	Local::writeMtpData();
-	App::wnd()->setupMain();
-
-	// "this" is already deleted here by creating the main widget.
-	if (weak && account->sessionExists()) {
-		auto &session = account->session();
-		if (!photo.isNull()) {
-			session.api().uploadPeerPhoto(session.user(), std::move(photo));
-		}
-		if (session.supportMode()) {
-			PrepareSupportMode();
-		}
-	}
-}
-
-void Widget::Step::paintEvent(QPaintEvent *e) {
-	Painter p(this);
-	paintAnimated(p, e->rect());
-}
-
-void Widget::Step::resizeEvent(QResizeEvent *e) {
-	updateLabelsPosition();
-}
-
-void Widget::Step::updateLabelsPosition() {
-	Ui::SendPendingMoveResizeEvents(_description->entity());
-	if (hasCover()) {
-		_title->moveToLeft((width() - _title->width()) / 2, contentTop() + st::introCoverTitleTop);
-		_description->moveToLeft((width() - _description->width()) / 2, contentTop() + st::introCoverDescriptionTop);
-	} else {
-		_title->moveToLeft(contentLeft() + st::buttonRadius, contentTop() + st::introTitleTop);
-		_description->resizeToWidth(st::introDescription.minWidth);
-		_description->moveToLeft(contentLeft() + st::buttonRadius, contentTop() + st::introDescriptionTop);
-	}
-	if (_error) {
-		if (_errorCentered) {
-			_error->entity()->resizeToWidth(width());
-		}
-		Ui::SendPendingMoveResizeEvents(_error->entity());
-		auto errorLeft = _errorCentered ? 0 : (contentLeft() + st::buttonRadius);
-		auto errorTop = contentTop() + (_errorBelowLink ? st::introErrorBelowLinkTop : st::introErrorTop);
-		_error->moveToLeft(errorLeft, errorTop);
-	}
-}
-
-void Widget::Step::setTitleText(rpl::producer<QString> titleText) {
-	_titleText = std::move(titleText);
-}
-
-void Widget::Step::setDescriptionText(
-		rpl::producer<QString> descriptionText) {
-	setDescriptionText(
-		std::move(descriptionText) | Ui::Text::ToWithEntities());
-}
-
-void Widget::Step::setDescriptionText(
-		rpl::producer<TextWithEntities> richDescriptionText) {
-	_descriptionText = std::move(richDescriptionText);
-}
-
-void Widget::Step::showFinished() {
-	_a_show.stop();
-	_coverAnimation = CoverAnimation();
-	_slideAnimation.reset();
-	prepareCoverMask();
-	activate();
-}
-
-bool Widget::Step::paintAnimated(Painter &p, QRect clip) {
-	if (_slideAnimation) {
-		_slideAnimation->paintFrame(p, (width() - st::introStepWidth) / 2, contentTop(), width());
-		if (!_slideAnimation->animating()) {
-			showFinished();
-			return false;
-		}
-		return true;
-	}
-
-	auto dt = _a_show.value(1.);
-	if (!_a_show.animating()) {
-		if (hasCover()) {
-			paintCover(p, 0);
-		}
-		if (_coverAnimation.title) {
-			showFinished();
-		}
-		if (!QRect(0, contentTop(), width(), st::introStepHeight).intersects(clip)) {
-			return true;
-		}
-		return false;
-	}
-
-	auto progress = (hasCover() ? anim::easeOutCirc(1., dt) : anim::linear(1., dt));
-	auto arrivingAlpha = progress;
-	auto departingAlpha = 1. - progress;
-	auto showCoverMethod = progress;
-	auto hideCoverMethod = progress;
-	auto coverTop = (hasCover() ? anim::interpolate(-st::introCoverHeight, 0, showCoverMethod) : anim::interpolate(0, -st::introCoverHeight, hideCoverMethod));
-
-	paintCover(p, coverTop);
-
-	auto positionReady = hasCover() ? showCoverMethod : hideCoverMethod;
-	_coverAnimation.title->paintFrame(p, positionReady, departingAlpha, arrivingAlpha);
-	_coverAnimation.description->paintFrame(p, positionReady, departingAlpha, arrivingAlpha);
-
-	paintContentSnapshot(p, _coverAnimation.contentSnapshotWas, departingAlpha, showCoverMethod);
-	paintContentSnapshot(p, _coverAnimation.contentSnapshotNow, arrivingAlpha, 1. - hideCoverMethod);
-
-	return true;
-}
-
-void Widget::Step::fillSentCodeData(const MTPDauth_sentCode &data) {
-	const auto &type = data.vtype();
-	switch (type.type()) {
-	case mtpc_auth_sentCodeTypeApp: {
-		getData()->codeByTelegram = true;
-		getData()->codeLength = type.c_auth_sentCodeTypeApp().vlength().v;
-	} break;
-	case mtpc_auth_sentCodeTypeSms: {
-		getData()->codeByTelegram = false;
-		getData()->codeLength = type.c_auth_sentCodeTypeSms().vlength().v;
-	} break;
-	case mtpc_auth_sentCodeTypeCall: {
-		getData()->codeByTelegram = false;
-		getData()->codeLength = type.c_auth_sentCodeTypeCall().vlength().v;
-	} break;
-	case mtpc_auth_sentCodeTypeFlashCall: LOG(("Error: should not be flashcall!")); break;
-	}
-}
-
-void Widget::Step::showDescription() {
-	_description->show(anim::type::normal);
-}
-
-void Widget::Step::hideDescription() {
-	_description->hide(anim::type::normal);
-}
-
-void Widget::Step::paintContentSnapshot(Painter &p, const QPixmap &snapshot, float64 alpha, float64 howMuchHidden) {
-	if (!snapshot.isNull()) {
-		auto contentTop = anim::interpolate(height() - (snapshot.height() / cIntRetinaFactor()), height(), howMuchHidden);
-		if (contentTop < height()) {
-			p.setOpacity(alpha);
-			p.drawPixmap(QPoint(contentLeft(), contentTop), snapshot, QRect(0, 0, snapshot.width(), (height() - contentTop) * cIntRetinaFactor()));
-		}
-	}
-}
-
-void Widget::Step::prepareCoverMask() {
-	if (!_coverMask.isNull()) return;
-
-	auto maskWidth = cIntRetinaFactor();
-	auto maskHeight = st::introCoverHeight * cIntRetinaFactor();
-	auto mask = QImage(maskWidth, maskHeight, QImage::Format_ARGB32_Premultiplied);
-	auto maskInts = reinterpret_cast<uint32*>(mask.bits());
-	Assert(mask.depth() == (sizeof(uint32) << 3));
-	auto maskIntsPerLineAdded = (mask.bytesPerLine() >> 2) - maskWidth;
-	Assert(maskIntsPerLineAdded >= 0);
-	auto realHeight = static_cast<float64>(maskHeight - 1);
-	for (auto y = 0; y != maskHeight; ++y) {
-		auto color = anim::color(st::introCoverTopBg, st::introCoverBottomBg, y / realHeight);
-		auto colorInt = anim::getPremultiplied(color);
-		for (auto x = 0; x != maskWidth; ++x) {
-			*maskInts++ = colorInt;
-		}
-		maskInts += maskIntsPerLineAdded;
-	}
-	_coverMask = App::pixmapFromImageInPlace(std::move(mask));
-}
-
-void Widget::Step::paintCover(Painter &p, int top) {
-	auto coverHeight = top + st::introCoverHeight;
-	if (coverHeight > 0) {
-		p.drawPixmap(QRect(0, 0, width(), coverHeight), _coverMask, QRect(0, -top * cIntRetinaFactor(), _coverMask.width(), coverHeight * cIntRetinaFactor()));
-	}
-
-	auto left = 0;
-	auto right = 0;
-	if (width() < st::introCoverMaxWidth) {
-		auto iconsMaxSkip = st::introCoverMaxWidth - st::introCoverLeft.width() - st::introCoverRight.width();
-		auto iconsSkip = st::introCoverIconsMinSkip + (iconsMaxSkip - st::introCoverIconsMinSkip) * (width() - st::introStepWidth) / (st::introCoverMaxWidth - st::introStepWidth);
-		auto outside = iconsSkip + st::introCoverLeft.width() + st::introCoverRight.width() - width();
-		left = -outside / 2;
-		right = -outside - left;
-	}
-	if (top < 0) {
-		auto shown = float64(coverHeight) / st::introCoverHeight;
-		auto leftShown = qRound(shown * (left + st::introCoverLeft.width()));
-		left = leftShown - st::introCoverLeft.width();
-		auto rightShown = qRound(shown * (right + st::introCoverRight.width()));
-		right = rightShown - st::introCoverRight.width();
-	}
-	st::introCoverLeft.paint(p, left, coverHeight - st::introCoverLeft.height(), width());
-	st::introCoverRight.paint(p, width() - right - st::introCoverRight.width(), coverHeight - st::introCoverRight.height(), width());
-
-	auto planeLeft = (width() - st::introCoverIcon.width()) / 2 - st::introCoverIconLeft;
-	auto planeTop = top + st::introCoverIconTop;
-	if (top < 0 && !_hasCover) {
-		auto deltaLeft = -qRound(float64(st::introPlaneWidth / st::introPlaneHeight) * top);
-//		auto deltaTop = top;
-		planeLeft += deltaLeft;
-	//	planeTop += top;
-	}
-	st::introCoverIcon.paint(p, planeLeft, planeTop, width());
-}
-
-int Widget::Step::contentLeft() const {
-	return (width() - st::introNextButton.width) / 2;
-}
-
-int Widget::Step::contentTop() const {
-	auto result = height() - st::introStepHeight - st::introStepHeightAdd;
-	if (_hasCover) {
-		auto added = 1. - snap(float64(height() - st::windowMinHeight) / (st::introStepHeightFull - st::windowMinHeight), 0., 1.);
-		result += qRound(added * st::introStepHeightAdd);
-	}
-	return result;
-}
-
-void Widget::Step::setErrorCentered(bool centered) {
-	_errorCentered = centered;
-	_error.destroy();
-}
-
-void Widget::Step::setErrorBelowLink(bool below) {
-	_errorBelowLink = below;
-	if (_error) {
-		updateLabelsPosition();
-	}
-}
-
-void Widget::Step::showError(rpl::producer<QString> text) {
-	_errorText = std::move(text);
-}
-
-void Widget::Step::refreshError(const QString &text) {
-	if (text.isEmpty()) {
-		if (_error) _error->hide(anim::type::normal);
-	} else {
-		if (!_error) {
-			_error.create(
-				this,
-				object_ptr<Ui::FlatLabel>(
-					this,
-					_errorCentered
-						? st::introErrorCentered
-						: st::introError));
-			_error->hide(anim::type::instant);
-		}
-		_error->entity()->setText(text);
-		updateLabelsPosition();
-		_error->show(anim::type::normal);
-	}
-}
-
-Widget::Step::Step(
-	QWidget *parent,
-	not_null<Main::Account*> account,
-	not_null<Data*> data,
-	bool hasCover)
-: RpWidget(parent)
-, _account(account)
-, _data(data)
-, _hasCover(hasCover)
-, _title(this, _hasCover ? st::introCoverTitle : st::introTitle)
-, _description(
-	this,
-	object_ptr<Ui::FlatLabel>(
-		this,
-		_hasCover
-			? st::introCoverDescription
-			: st::introDescription)) {
-	hide();
-	subscribe(Window::Theme::Background(), [this](
-			const Window::Theme::BackgroundUpdate &update) {
-		if (update.paletteChanged()) {
-			if (!_coverMask.isNull()) {
-				_coverMask = QPixmap();
-				prepareCoverMask();
-			}
-		}
-	});
-
-	_errorText.value(
-	) | rpl::start_with_next([=](const QString &text) {
-		refreshError(text);
-	}, lifetime());
-
-	_titleText.value(
-	) | rpl::start_with_next([=](const QString &text) {
-		_title->setText(text);
-		updateLabelsPosition();
-	}, lifetime());
-
-	_descriptionText.value(
-	) | rpl::start_with_next([=](const TextWithEntities &text) {
-		_description->entity()->setMarkedText(text);
-		updateLabelsPosition();
-	}, lifetime());
-}
-
-void Widget::Step::prepareShowAnimated(Step *after) {
-	setInnerFocus();
-	if (hasCover() || after->hasCover()) {
-		_coverAnimation = prepareCoverAnimation(after);
-		prepareCoverMask();
-	} else {
-		auto leftSnapshot = after->prepareSlideAnimation();
-		auto rightSnapshot = prepareSlideAnimation();
-		_slideAnimation = std::make_unique<Ui::SlideAnimation>();
-		_slideAnimation->setSnapshots(std::move(leftSnapshot), std::move(rightSnapshot));
-		_slideAnimation->setOverflowHidden(false);
-	}
-}
-
-Widget::Step::CoverAnimation Widget::Step::prepareCoverAnimation(Step *after) {
-	auto result = CoverAnimation();
-	result.title = Ui::FlatLabel::CrossFade(
-		after->_title,
-		_title,
-		st::introBg);
-	result.description = Ui::FlatLabel::CrossFade(
-		after->_description->entity(),
-		_description->entity(),
-		st::introBg,
-		after->_description->pos(),
-		_description->pos());
-	result.contentSnapshotWas = after->prepareContentSnapshot();
-	result.contentSnapshotNow = prepareContentSnapshot();
-	return result;
-}
-
-QPixmap Widget::Step::prepareContentSnapshot() {
-	auto otherTop = _description->y() + _description->height();
-	auto otherRect = myrtlrect(contentLeft(), otherTop, st::introStepWidth, height() - otherTop);
-	return Ui::GrabWidget(this, otherRect);
-}
-
-QPixmap Widget::Step::prepareSlideAnimation() {
-	auto grabLeft = (width() - st::introStepWidth) / 2;
-	auto grabTop = contentTop();
-	return Ui::GrabWidget(
-		this,
-		QRect(grabLeft, grabTop, st::introStepWidth, st::introStepHeight));
-}
-
-void Widget::Step::showAnimated(Direction direction) {
-	setFocus();
-	show();
-	hideChildren();
-	if (_slideAnimation) {
-		auto slideLeft = (direction == Direction::Back);
-		_slideAnimation->start(slideLeft, [this] { update(0, contentTop(), width(), st::introStepHeight); }, st::introSlideDuration);
-	} else {
-		_a_show.start([this] { update(); }, 0., 1., st::introCoverDuration);
-	}
-}
-
-void Widget::Step::setGoCallback(Fn<void(Step *step, Direction direction)> callback) {
-	_goCallback = std::move(callback);
-}
-
-void Widget::Step::setShowResetCallback(Fn<void()> callback) {
-	_showResetCallback = std::move(callback);
-}
-
-void Widget::Step::setShowTermsCallback(Fn<void()> callback) {
-	_showTermsCallback = std::move(callback);
-}
-
-void Widget::Step::setAcceptTermsCallback(
-		Fn<void(Fn<void()> callback)> callback) {
-	_acceptTermsCallback = std::move(callback);
-}
-
-void Widget::Step::showFast() {
-	show();
-	showFinished();
-}
-
-bool Widget::Step::animating() const {
-	return (_slideAnimation && _slideAnimation->animating()) || _a_show.animating();
-}
-
-bool Widget::Step::hasCover() const {
-	return _hasCover;
-}
-
-bool Widget::Step::hasBack() const {
-	return false;
-}
-
-void Widget::Step::activate() {
-	_title->show();
-	_description->show(anim::type::instant);
-	if (!_errorText.current().isEmpty()) {
-		_error->show(anim::type::instant);
-	}
-}
-
-void Widget::Step::cancelled() {
-}
-
-void Widget::Step::finished() {
-	hide();
-}
-
-Widget::Step::CoverAnimation::~CoverAnimation() = default;
-
-Widget::Step::~Step() = default;
-
 } // namespace Intro
diff --git a/Telegram/SourceFiles/intro/introwidget.h b/Telegram/SourceFiles/intro/introwidget.h
index 58d49d524..4d2f69411 100644
--- a/Telegram/SourceFiles/intro/introwidget.h
+++ b/Telegram/SourceFiles/intro/introwidget.h
@@ -21,8 +21,6 @@ namespace Ui {
 class IconButton;
 class RoundButton;
 class LinkButton;
-class SlideAnimation;
-class CrossFadeAnimation;
 class FlatLabel;
 template <typename Widget>
 class FadeWrap;
@@ -33,10 +31,51 @@ class ConnectionState;
 } // namespace Window
 
 namespace Intro {
+namespace details {
 
-class Widget : public Ui::RpWidget, private MTP::Sender, private base::Subscriber {
-	Q_OBJECT
+enum class CallStatus {
+	Waiting,
+	Calling,
+	Called,
+	Disabled,
+};
 
+struct Data {
+	QString country;
+	QString phone;
+	QByteArray phoneHash;
+
+	CallStatus callStatus = CallStatus::Disabled;
+	int callTimeout = 0;
+
+	int codeLength = 5;
+	bool codeByTelegram = false;
+
+	Core::CloudPasswordCheckRequest pwdRequest;
+	bool hasRecovery = false;
+	QString pwdHint;
+	bool pwdNotEmptyPassport = false;
+
+	Window::TermsLock termsLock;
+
+	base::Observable<void> updated;
+
+};
+
+enum class Direction {
+	Back,
+	Forward,
+	Replace,
+};
+
+class Step;
+
+} // namespace details
+
+class Widget
+	: public Ui::RpWidget
+	, private MTP::Sender
+	, private base::Subscriber {
 public:
 	Widget(QWidget *parent, not_null<Main::Account*> account);
 
@@ -51,221 +90,22 @@ protected:
 	void resizeEvent(QResizeEvent *e) override;
 	void keyPressEvent(QKeyEvent *e) override;
 
-signals:
-	void countryChanged();
-
-private slots:
-	void onCheckUpdateStatus();
-
-	// Internal interface.
-public:
-	struct Data {
-		QString country;
-		QString phone;
-		QByteArray phoneHash;
-
-		enum class CallStatus {
-			Waiting,
-			Calling,
-			Called,
-			Disabled,
-		};
-		CallStatus callStatus = CallStatus::Disabled;
-		int callTimeout = 0;
-
-		int codeLength = 5;
-		bool codeByTelegram = false;
-
-		Core::CloudPasswordCheckRequest pwdRequest;
-		bool hasRecovery = false;
-		QString pwdHint;
-		bool pwdNotEmptyPassport = false;
-
-		Window::TermsLock termsLock;
-
-		base::Observable<void> updated;
-
-	};
-
-	enum class Direction {
-		Back,
-		Forward,
-		Replace,
-	};
-	class Step : public Ui::RpWidget, public RPCSender, protected base::Subscriber {
-	public:
-		Step(
-			QWidget *parent,
-			not_null<Main::Account*> account,
-			not_null<Data*> data,
-			bool hasCover = false);
-
-		Main::Account &account() const {
-			return *_account;
-		}
-
-		virtual void finishInit() {
-		}
-		virtual void setInnerFocus() {
-			setFocus();
-		}
-
-		void setGoCallback(
-			Fn<void(Step *step, Direction direction)> callback);
-		void setShowResetCallback(Fn<void()> callback);
-		void setShowTermsCallback(
-			Fn<void()> callback);
-		void setAcceptTermsCallback(
-			Fn<void(Fn<void()> callback)> callback);
-
-		void prepareShowAnimated(Step *after);
-		void showAnimated(Direction direction);
-		void showFast();
-		bool animating() const;
-
-		bool hasCover() const;
-		virtual bool hasBack() const;
-		virtual void activate();
-		virtual void cancelled();
-		virtual void finished();
-
-		virtual void submit() = 0;
-		virtual rpl::producer<QString> nextButtonText() const;
-
-		int contentLeft() const;
-		int contentTop() const;
-
-		void setErrorCentered(bool centered);
-		void setErrorBelowLink(bool below);
-		void showError(rpl::producer<QString> text);
-		void hideError() {
-			showError(rpl::single(QString()));
-		}
-
-		~Step();
-
-	protected:
-		void paintEvent(QPaintEvent *e) override;
-		void resizeEvent(QResizeEvent *e) override;
-
-		void setTitleText(rpl::producer<QString> titleText);
-		void setDescriptionText(rpl::producer<QString> descriptionText);
-		void setDescriptionText(
-			rpl::producer<TextWithEntities> richDescriptionText);
-		bool paintAnimated(Painter &p, QRect clip);
-
-		void fillSentCodeData(const MTPDauth_sentCode &type);
-
-		void showDescription();
-		void hideDescription();
-
-		not_null<Data*> getData() const {
-			return _data;
-		}
-		void finish(const MTPUser &user, QImage &&photo = QImage());
-
-		void goBack() {
-			if (_goCallback) {
-				_goCallback(nullptr, Direction::Back);
-			}
-		}
-
-		template <typename StepType>
-		void goNext() {
-			if (_goCallback) {
-				_goCallback(
-					new StepType(parentWidget(), _account, _data),
-					Direction::Forward);
-			}
-		}
-
-		template <typename StepType>
-		void goReplace() {
-			if (_goCallback) {
-				_goCallback(
-					new StepType(parentWidget(), _account, _data),
-					Direction::Replace);
-			}
-		}
-		void showResetButton() {
-			if (_showResetCallback) _showResetCallback();
-		}
-		void showTerms() {
-			if (_showTermsCallback) _showTermsCallback();
-		}
-		void acceptTerms(Fn<void()> callback) {
-			if (_acceptTermsCallback) {
-				_acceptTermsCallback(callback);
-			}
-		}
-
-	private:
-		struct CoverAnimation {
-			CoverAnimation() = default;
-			CoverAnimation(CoverAnimation &&other) = default;
-			CoverAnimation &operator=(CoverAnimation &&other) = default;
-			~CoverAnimation();
-
-			std::unique_ptr<Ui::CrossFadeAnimation> title;
-			std::unique_ptr<Ui::CrossFadeAnimation> description;
-
-			// From content top till the next button top.
-			QPixmap contentSnapshotWas;
-			QPixmap contentSnapshotNow;
-		};
-		void updateLabelsPosition();
-		void paintContentSnapshot(Painter &p, const QPixmap &snapshot, float64 alpha, float64 howMuchHidden);
-		void refreshError(const QString &text);
-
-		CoverAnimation prepareCoverAnimation(Step *step);
-		QPixmap prepareContentSnapshot();
-		QPixmap prepareSlideAnimation();
-		void showFinished();
-
-		void prepareCoverMask();
-		void paintCover(Painter &p, int top);
-
-		const not_null<Main::Account*> _account;
-		const not_null<Data*> _data;
-
-		bool _hasCover = false;
-		Fn<void(Step *step, Direction direction)> _goCallback;
-		Fn<void()> _showResetCallback;
-		Fn<void()> _showTermsCallback;
-		Fn<void(Fn<void()> callback)> _acceptTermsCallback;
-
-		rpl::variable<QString> _titleText;
-		object_ptr<Ui::FlatLabel> _title;
-		rpl::variable<TextWithEntities> _descriptionText;
-		object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _description;
-
-		bool _errorCentered = false;
-		bool _errorBelowLink = false;
-		rpl::variable<QString> _errorText;
-		object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _error = { nullptr };
-
-		Ui::Animations::Simple _a_show;
-		CoverAnimation _coverAnimation;
-		std::unique_ptr<Ui::SlideAnimation> _slideAnimation;
-		QPixmap _coverMask;
-
-	};
-
 private:
 	void setupConnectingWidget();
 	void refreshLang();
 	void animationCallback();
 	void createLanguageLink();
+	void checkUpdateStatus();
+	void setupNextButton();
 
 	void updateControlsGeometry();
-	not_null<Data*> getData() {
+	[[nodiscard]] not_null<details::Data*> getData() {
 		return &_data;
 	}
 
 	void fixOrder();
 	void showControls();
 	void hideControls();
-	QRect calculateStepRect() const;
 
 	void showResetButton();
 	void resetAccount();
@@ -274,13 +114,15 @@ private:
 	void acceptTerms(Fn<void()> callback);
 	void hideAndDestroy(object_ptr<Ui::FadeWrap<Ui::RpWidget>> widget);
 
-	Step *getStep(int skip = 0) {
-		Assert(_stepHistory.size() + skip > 0);
-		return _stepHistory.at(_stepHistory.size() - skip - 1);
+	[[nodiscard]] details::Step *getStep(int skip = 0) const {
+		Expects(skip >= 0);
+		Expects(skip < _stepHistory.size());
+
+		return _stepHistory[_stepHistory.size() - skip - 1];
 	}
-	void historyMove(Direction direction);
-	void moveToStep(Step *step, Direction direction);
-	void appendStep(Step *step);
+	void historyMove(details::Direction direction);
+	void moveToStep(details::Step *step, details::Direction direction);
+	void appendStep(details::Step *step);
 
 	void getNearestDC();
 	void showTerms(Fn<void()> callback);
@@ -291,9 +133,9 @@ private:
 	bool _showBack = false;
 	QPixmap _cacheUnder, _cacheOver;
 
-	QVector<Step*> _stepHistory;
+	std::vector<details::Step*> _stepHistory;
 
-	Data _data;
+	details::Data _data;
 
 	Ui::Animations::Simple _coverShownAnimation;
 	int _nextTopFrom = 0;
@@ -310,6 +152,9 @@ private:
 
 	std::unique_ptr<Window::ConnectionState> _connecting;
 
+	bool _nextShown = false;
+	Ui::Animations::Simple _nextShownAnimation;
+
 	mtpRequestId _resetRequest = 0;
 
 };
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index ca6bea78e..37b643429 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -446,6 +446,8 @@
 <(src_loc)/intro/introstart.h
 <(src_loc)/intro/intro_qr.cpp
 <(src_loc)/intro/intro_qr.h
+<(src_loc)/intro/intro_step.cpp
+<(src_loc)/intro/intro_step.h
 <(src_loc)/lang/lang_cloud_manager.cpp
 <(src_loc)/lang/lang_cloud_manager.h
 <(src_loc)/lang/lang_file_parser.cpp
diff --git a/Telegram/lib_qr b/Telegram/lib_qr
index 6111aa3ce..4b0a1d5fb 160000
--- a/Telegram/lib_qr
+++ b/Telegram/lib_qr
@@ -1 +1 @@
-Subproject commit 6111aa3cef49d481d6450f463cfc4fe482755db7
+Subproject commit 4b0a1d5fb546af4671048aeeec9c355a67a12a01

From 7dbba7577656c8296cfaeaae86059c289426d891 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 26 Nov 2019 14:39:54 +0300
Subject: [PATCH 55/91] Make login QR follow the color theme.

---
 Telegram/SourceFiles/intro/intro.style     |  1 +
 Telegram/SourceFiles/intro/intro_qr.cpp    | 29 +++++++++++-----------
 Telegram/SourceFiles/intro/introwidget.cpp | 21 +++++++++++-----
 Telegram/SourceFiles/intro/introwidget.h   |  2 +-
 Telegram/lib_qr                            |  2 +-
 5 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/Telegram/SourceFiles/intro/intro.style b/Telegram/SourceFiles/intro/intro.style
index 95af195b7..8491d5b14 100644
--- a/Telegram/SourceFiles/intro/intro.style
+++ b/Telegram/SourceFiles/intro/intro.style
@@ -75,6 +75,7 @@ introHeight: 406px;
 introStepTopMin: 76px;
 introStepWidth: 380px;
 introNextTop: 266px;
+introNextSlide: 200px;
 introStepHeight: 384px;
 introContentTopAdd: 30px;
 introStepHeightFull: 590px;
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index a7b6c1679..fe6971903 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -14,6 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/wrap/fade_wrap.h"
 #include "ui/wrap/vertical_layout.h"
 #include "ui/text/text_utilities.h"
+#include "ui/image/image_prepare.h"
 #include "main/main_account.h"
 #include "boxes/confirm_box.h"
 #include "core/application.h"
@@ -50,9 +51,10 @@ namespace {
 }
 
 [[nodiscard]] QImage TelegramQrExact(const Qr::Data &data, int pixel) {
-	return Qr::ReplaceCenter(
-		Qr::Generate(data, pixel),
-		TelegramLogoImage(Qr::ReplaceSize(data, pixel)));
+	return Qr::Generate(data, pixel, st::windowFg->c);
+	//Qr::ReplaceCenter(
+	//	Qr::Generate(data, pixel),
+	//	TelegramLogoImage(Qr::ReplaceSize(data, pixel)));
 }
 
 [[nodiscard]] QImage TelegramQr(const Qr::Data &data, int pixel, int max = 0) {
@@ -64,21 +66,20 @@ namespace {
 	return TelegramQrExact(data, pixel * style::DevicePixelRatio());
 }
 
-[[nodiscard]] QImage TelegramQr(const QString &text, int pixel, int max) {
-	return TelegramQr(
-		Qr::Encode(text, Qr::Redundancy::Quartile),
-		pixel,
-		max);
-}
-
 [[nodiscard]] not_null<Ui::RpWidget*> PrepareQrWidget(
 		not_null<QWidget*> parent,
 		rpl::producer<QByteArray> codes) {
-	auto result = Ui::CreateChild<Ui::RpWidget>(parent.get());
-	auto current = result->lifetime().make_state<QImage>();
-	std::move(
+	auto qrs = std::move(
 		codes
 	) | rpl::map([](const QByteArray &code) {
+		return Qr::Encode(code, Qr::Redundancy::Quartile);
+	});
+	auto result = Ui::CreateChild<Ui::RpWidget>(parent.get());
+	auto current = result->lifetime().make_state<QImage>();
+	rpl::combine(
+		std::move(qrs),
+		rpl::single(rpl::empty_value()) | rpl::then(style::PaletteChanged())
+	) | rpl::map([](const Qr::Data &code, const auto &) {
 		return TelegramQr(code, st::introQrPixel, st::introQrMaxSize);
 	}) | rpl::start_with_next([=](QImage &&image) {
 		result->resize(image.size() / cIntRetinaFactor());
@@ -102,7 +103,7 @@ QrWidget::QrWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
 	not_null<Data*> data)
-	: Step(parent, account, data)
+: Step(parent, account, data)
 	, _refreshTimer([=] { refreshCode(); }) {
 	setTitleText(rpl::single(QString()));
 	setDescriptionText(rpl::single(QString()));
diff --git a/Telegram/SourceFiles/intro/introwidget.cpp b/Telegram/SourceFiles/intro/introwidget.cpp
index c183069f6..98b6d5524 100644
--- a/Telegram/SourceFiles/intro/introwidget.cpp
+++ b/Telegram/SourceFiles/intro/introwidget.cpp
@@ -48,7 +48,12 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 		this,
 		tr::lng_menu_settings(),
 		st::defaultBoxButton))
-, _next(this, nullptr, st::introNextButton) {
+, _next(
+	this,
+	object_ptr<Ui::RoundButton>(
+		this,
+		nullptr,
+		st::introNextButton)) {
 	getData()->country = Platform::SystemCountry();
 
 	_back->entity()->setClickedCallback([=] {
@@ -56,7 +61,7 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 	});
 	_back->hide(anim::type::instant);
 
-	_next->setClickedCallback([this] { getStep()->submit(); });
+	_next->entity()->setClickedCallback([this] { getStep()->submit(); });
 
 	_settings->entity()->setClickedCallback([] { App::wnd()->showSettings(); });
 
@@ -475,8 +480,8 @@ void Widget::showTerms(Fn<void()> callback) {
 
 void Widget::showControls() {
 	getStep()->show();
-	_next->show();
 	setupNextButton();
+	_next->show(anim::type::instant);
 	_nextShownAnimation.stop();
 	_connecting->setForceHidden(false);
 	auto hasCover = getStep()->hasCover();
@@ -496,7 +501,7 @@ void Widget::showControls() {
 }
 
 void Widget::setupNextButton() {
-	_next->setText(getStep()->nextButtonText(
+	_next->entity()->setText(getStep()->nextButtonText(
 	) | rpl::filter([](const QString &text) {
 		return !text.isEmpty();
 	}));
@@ -507,6 +512,7 @@ void Widget::setupNextButton() {
 	std::move(
 		visible
 	) | rpl::start_with_next([=](bool visible) {
+		_next->toggle(visible, anim::type::normal);
 		_nextShown = visible;
 		_nextShownAnimation.start(
 			[=] { updateControlsGeometry(); },
@@ -518,7 +524,7 @@ void Widget::setupNextButton() {
 
 void Widget::hideControls() {
 	getStep()->hide();
-	_next->hide();
+	_next->hide(anim::type::instant);
 	_connecting->setForceHidden(true);
 	_settings->hide(anim::type::instant);
 	if (_update) _update->hide(anim::type::instant);
@@ -605,7 +611,10 @@ void Widget::updateControlsGeometry() {
 	auto nextTopTo = getStep()->contentTop() + st::introNextTop;
 	auto nextTop = anim::interpolate(_nextTopFrom, nextTopTo, shown);
 	const auto shownAmount = _nextShownAnimation.value(_nextShown ? 1. : 0.);
-	const auto realNextTop = anim::interpolate(height(), nextTop, shownAmount);
+	const auto realNextTop = anim::interpolate(
+		nextTop + st::introNextSlide,
+		nextTop,
+		shownAmount);
 	_next->moveToLeft((width() - _next->width()) / 2, realNextTop);
 	if (_changeLanguage) {
 		_changeLanguage->moveToLeft((width() - _changeLanguage->width()) / 2, _next->y() + _next->height() + _changeLanguage->height());
diff --git a/Telegram/SourceFiles/intro/introwidget.h b/Telegram/SourceFiles/intro/introwidget.h
index 4d2f69411..f56f984df 100644
--- a/Telegram/SourceFiles/intro/introwidget.h
+++ b/Telegram/SourceFiles/intro/introwidget.h
@@ -145,7 +145,7 @@ private:
 	object_ptr<Ui::FadeWrap<Ui::RoundButton>> _update = { nullptr };
 	object_ptr<Ui::FadeWrap<Ui::RoundButton>> _settings;
 
-	object_ptr<Ui::RoundButton> _next;
+	object_ptr<Ui::FadeWrap<Ui::RoundButton>> _next;
 	object_ptr<Ui::FadeWrap<Ui::LinkButton>> _changeLanguage = { nullptr };
 	object_ptr<Ui::FadeWrap<Ui::RoundButton>> _resetAccount = { nullptr };
 	object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _terms = { nullptr };
diff --git a/Telegram/lib_qr b/Telegram/lib_qr
index 4b0a1d5fb..1efe65125 160000
--- a/Telegram/lib_qr
+++ b/Telegram/lib_qr
@@ -1 +1 @@
-Subproject commit 4b0a1d5fb546af4671048aeeec9c355a67a12a01
+Subproject commit 1efe65125ddca2a4a663c004380f31befd22ea76

From ba7762305eef955d9738d82ef45658d99c9345c5 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 26 Nov 2019 15:56:07 +0300
Subject: [PATCH 56/91] Use special plane icon for login QR.

---
 Telegram/Resources/icons/intro_qr_plane.png   | Bin 0 -> 635 bytes
 .../Resources/icons/intro_qr_plane@2x.png     | Bin 0 -> 1264 bytes
 .../Resources/icons/intro_qr_plane@3x.png     | Bin 0 -> 1921 bytes
 Telegram/SourceFiles/intro/intro.style        |   6 +-
 Telegram/SourceFiles/intro/intro_qr.cpp       |  76 +++++++++++-------
 5 files changed, 52 insertions(+), 30 deletions(-)
 create mode 100644 Telegram/Resources/icons/intro_qr_plane.png
 create mode 100644 Telegram/Resources/icons/intro_qr_plane@2x.png
 create mode 100644 Telegram/Resources/icons/intro_qr_plane@3x.png

diff --git a/Telegram/Resources/icons/intro_qr_plane.png b/Telegram/Resources/icons/intro_qr_plane.png
new file mode 100644
index 0000000000000000000000000000000000000000..cdc309f9d8c90c02b84e6824b3026a2958d65aca
GIT binary patch
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literal 0
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diff --git a/Telegram/Resources/icons/intro_qr_plane@2x.png b/Telegram/Resources/icons/intro_qr_plane@2x.png
new file mode 100644
index 0000000000000000000000000000000000000000..3d0c2e9afb737e266037a3b962541e9a53a912c6
GIT binary patch
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diff --git a/Telegram/Resources/icons/intro_qr_plane@3x.png b/Telegram/Resources/icons/intro_qr_plane@3x.png
new file mode 100644
index 0000000000000000000000000000000000000000..ae5c5442e1db6aae8c5ae79a4d1b3e8d9be8c443
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diff --git a/Telegram/SourceFiles/intro/intro.style b/Telegram/SourceFiles/intro/intro.style
index 8491d5b14..c9d4be939 100644
--- a/Telegram/SourceFiles/intro/intro.style
+++ b/Telegram/SourceFiles/intro/intro.style
@@ -162,9 +162,9 @@ introBackButton: IconButton(defaultIconButton) {
 	}
 }
 
-introQrTop: 0px;
+introQrTop: -6px;
 introQrPixel: 50px; // large enough
-introQrMaxSize: 170px;
+introQrMaxSize: 180px;
 introQrLabelsWidth: 292px;
 introQrTitle: FlatLabel(defaultFlatLabel) {
 	textFg: introTitleFg;
@@ -179,3 +179,5 @@ introQrStep: defaultFlatLabel;
 introQrStepsTop: 232px;
 introQrStepMargins: margins(0px, 8px, 0px, 0px);
 introQrSkipTop: 360px;
+introQrCenterSize: 44px;
+introQrPlane: icon {{ "intro_qr_plane", activeButtonFg }};
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index fe6971903..3ee26130e 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -15,6 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/wrap/vertical_layout.h"
 #include "ui/text/text_utilities.h"
 #include "ui/image/image_prepare.h"
+#include "ui/painter.h"
 #include "main/main_account.h"
 #include "boxes/confirm_box.h"
 #include "core/application.h"
@@ -26,35 +27,26 @@ namespace Intro {
 namespace details {
 namespace {
 
-[[nodiscard]] QImage TelegramLogoImage(int size) {
-	constexpr auto kScale = 0.8;
-	const auto used = int(size * kScale);
-	const auto adjusted = used + ((used % 2) + (size % 2)) % 2;
-	const auto image = Core::App().logo().scaled(
-		adjusted,
-		adjusted,
-		Qt::KeepAspectRatio,
-		Qt::SmoothTransformation);
-	auto result = QImage(size, size, QImage::Format_ARGB32_Premultiplied);
+[[nodiscard]] QImage TelegramLogoImage() {
+	const auto size = QSize(st::introQrCenterSize, st::introQrCenterSize);
+	auto result = QImage(
+		size * style::DevicePixelRatio(),
+		QImage::Format_ARGB32_Premultiplied);
 	result.fill(Qt::transparent);
+	result.setDevicePixelRatio(style::DevicePixelRatio());
 	{
-		QPainter p(&result);
-		p.drawImage(
-			QRect(
-			(size - adjusted) / 2,
-				(size - adjusted) / 2,
-				adjusted,
-				adjusted),
-			image);
+		auto p = QPainter(&result);
+		auto hq = PainterHighQualityEnabler(p);
+		p.setBrush(st::activeButtonBg);
+		p.setPen(Qt::NoPen);
+		p.drawEllipse(QRect(QPoint(), size));
+		st::introQrPlane.paintInCenter(p, QRect(QPoint(), size));
 	}
 	return result;
 }
 
 [[nodiscard]] QImage TelegramQrExact(const Qr::Data &data, int pixel) {
 	return Qr::Generate(data, pixel, st::windowFg->c);
-	//Qr::ReplaceCenter(
-	//	Qr::Generate(data, pixel),
-	//	TelegramLogoImage(Qr::ReplaceSize(data, pixel)));
 }
 
 [[nodiscard]] QImage TelegramQr(const Qr::Data &data, int pixel, int max = 0) {
@@ -74,25 +66,53 @@ namespace {
 	) | rpl::map([](const QByteArray &code) {
 		return Qr::Encode(code, Qr::Redundancy::Quartile);
 	});
+	auto palettes = rpl::single(
+		rpl::empty_value()
+	) | rpl::then(
+		style::PaletteChanged()
+	);
 	auto result = Ui::CreateChild<Ui::RpWidget>(parent.get());
-	auto current = result->lifetime().make_state<QImage>();
+	const auto current = result->lifetime().make_state<QImage>();
+	const auto center = result->lifetime().make_state<QImage>();
+	result->resize(st::introQrMaxSize, st::introQrMaxSize);
 	rpl::combine(
 		std::move(qrs),
-		rpl::single(rpl::empty_value()) | rpl::then(style::PaletteChanged())
+		rpl::duplicate(palettes)
 	) | rpl::map([](const Qr::Data &code, const auto &) {
 		return TelegramQr(code, st::introQrPixel, st::introQrMaxSize);
 	}) | rpl::start_with_next([=](QImage &&image) {
-		result->resize(image.size() / cIntRetinaFactor());
 		*current = std::move(image);
 		result->update();
 	}, result->lifetime());
+	std::move(
+		palettes
+	) | rpl::map([] {
+		return TelegramLogoImage();
+	}) | rpl::start_with_next([=](QImage &&image) {
+		*center = std::move(image);
+	}, result->lifetime());
 	result->paintRequest(
 	) | rpl::filter([=] {
-		return !current->isNull();
+		return !center->isNull();
 	}) | rpl::start_with_next([=](QRect clip) {
-		QPainter(result).drawImage(
-			QRect(QPoint(), current->size() / cIntRetinaFactor()),
-			*current);
+		auto p = QPainter(result);
+		p.drawImage(
+			QRect(
+				(result->width() - st::introQrCenterSize) / 2,
+				(result->height() - st::introQrCenterSize) / 2,
+				st::introQrCenterSize,
+				st::introQrCenterSize),
+			*center);
+		if (current) {
+			const auto size = current->size() / cIntRetinaFactor();
+			p.drawImage(
+				QRect(
+					(result->width() - size.width()) / 2,
+					(result->height() - size.height()) / 2,
+					size.width(),
+					size.height()),
+				*current);
+		}
 	}, result->lifetime());
 	return result;
 }

From f4bf79b06709a7dae31c3c7fc002922dbfa13607 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 26 Nov 2019 16:17:19 +0300
Subject: [PATCH 57/91] Add QR code generation progress.

---
 Telegram/SourceFiles/intro/intro_qr.cpp   | 58 ++++++++++++++++-------
 Telegram/SourceFiles/intro/intro_step.cpp |  3 +-
 2 files changed, 43 insertions(+), 18 deletions(-)

diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index 3ee26130e..908aedc9a 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/labels.h"
 #include "ui/wrap/fade_wrap.h"
 #include "ui/wrap/vertical_layout.h"
+#include "ui/effects/radial_animation.h"
 #include "ui/text/text_utilities.h"
 #include "ui/image/image_prepare.h"
 #include "ui/painter.h"
@@ -61,6 +62,15 @@ namespace {
 [[nodiscard]] not_null<Ui::RpWidget*> PrepareQrWidget(
 		not_null<QWidget*> parent,
 		rpl::producer<QByteArray> codes) {
+	struct State {
+		explicit State(Fn<void()> callback)
+		: waiting(callback, st::defaultInfiniteRadialAnimation) {
+		}
+
+		QImage qr;
+		QImage center;
+		Ui::InfiniteRadialAnimation waiting;
+	};
 	auto qrs = std::move(
 		codes
 	) | rpl::map([](const QByteArray &code) {
@@ -72,8 +82,9 @@ namespace {
 		style::PaletteChanged()
 	);
 	auto result = Ui::CreateChild<Ui::RpWidget>(parent.get());
-	const auto current = result->lifetime().make_state<QImage>();
-	const auto center = result->lifetime().make_state<QImage>();
+	const auto state = result->lifetime().make_state<State>(
+		[=] { result->update(); });
+	state->waiting.start();
 	result->resize(st::introQrMaxSize, st::introQrMaxSize);
 	rpl::combine(
 		std::move(qrs),
@@ -81,7 +92,8 @@ namespace {
 	) | rpl::map([](const Qr::Data &code, const auto &) {
 		return TelegramQr(code, st::introQrPixel, st::introQrMaxSize);
 	}) | rpl::start_with_next([=](QImage &&image) {
-		*current = std::move(image);
+		state->qr = std::move(image);
+		state->waiting.stop();
 		result->update();
 	}, result->lifetime());
 	std::move(
@@ -89,29 +101,41 @@ namespace {
 	) | rpl::map([] {
 		return TelegramLogoImage();
 	}) | rpl::start_with_next([=](QImage &&image) {
-		*center = std::move(image);
+		state->center = std::move(image);
 	}, result->lifetime());
 	result->paintRequest(
-	) | rpl::filter([=] {
-		return !center->isNull();
-	}) | rpl::start_with_next([=](QRect clip) {
+	) | rpl::start_with_next([=](QRect clip) {
 		auto p = QPainter(result);
-		p.drawImage(
-			QRect(
-				(result->width() - st::introQrCenterSize) / 2,
-				(result->height() - st::introQrCenterSize) / 2,
-				st::introQrCenterSize,
-				st::introQrCenterSize),
-			*center);
-		if (current) {
-			const auto size = current->size() / cIntRetinaFactor();
+		auto rect = QRect(
+			(result->width() - st::introQrCenterSize) / 2,
+			(result->height() - st::introQrCenterSize) / 2,
+			st::introQrCenterSize,
+			st::introQrCenterSize);
+		p.drawImage(rect, state->center);
+		if (!anim::Disabled() && state->waiting.animating()) {
+			auto hq = PainterHighQualityEnabler(p);
+			const auto line = st::radialLine;
+			const auto radial = state->waiting.computeState();
+			auto pen = st::activeButtonBg->p;
+			pen.setWidth(line);
+			pen.setCapStyle(Qt::RoundCap);
+			p.setOpacity(radial.shown);
+			p.setPen(pen);
+			p.drawArc(
+				rect.marginsAdded({ line, line, line, line }),
+				radial.arcFrom,
+				radial.arcLength);
+			p.setOpacity(1.);
+		}
+		if (!state->qr.isNull()) {
+			const auto size = state->qr.size() / cIntRetinaFactor();
 			p.drawImage(
 				QRect(
 					(result->width() - size.width()) / 2,
 					(result->height() - size.height()) / 2,
 					size.width(),
 					size.height()),
-				*current);
+				state->qr);
 		}
 	}, result->lifetime());
 	return result;
diff --git a/Telegram/SourceFiles/intro/intro_step.cpp b/Telegram/SourceFiles/intro/intro_step.cpp
index 99100704c..6afa818dc 100644
--- a/Telegram/SourceFiles/intro/intro_step.cpp
+++ b/Telegram/SourceFiles/intro/intro_step.cpp
@@ -478,7 +478,8 @@ void Step::showFast() {
 }
 
 bool Step::animating() const {
-	return (_slideAnimation && _slideAnimation->animating()) || _a_show.animating();
+	return (_slideAnimation && _slideAnimation->animating())
+		|| _a_show.animating();
 }
 
 bool Step::hasCover() const {

From a0152557ecbf4539c7e01ec7b82abd51a1311ea6 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 26 Nov 2019 17:27:09 +0300
Subject: [PATCH 58/91] Cross-fade login QR.

---
 Telegram/SourceFiles/intro/intro.style       |  1 +
 Telegram/SourceFiles/intro/intro_qr.cpp      | 60 ++++++++++++++------
 Telegram/SourceFiles/intro/intro_qr.h        |  2 +
 Telegram/SourceFiles/intro/intro_step.cpp    | 14 ++---
 Telegram/SourceFiles/intro/intro_step.h      |  3 +-
 Telegram/SourceFiles/intro/introcode.cpp     |  5 +-
 Telegram/SourceFiles/intro/introcode.h       |  2 +
 Telegram/SourceFiles/intro/intropwdcheck.cpp |  5 +-
 Telegram/SourceFiles/intro/intropwdcheck.h   |  2 +
 Telegram/SourceFiles/intro/introwidget.cpp   | 23 ++++----
 Telegram/SourceFiles/intro/introwidget.h     |  2 +-
 11 files changed, 78 insertions(+), 41 deletions(-)

diff --git a/Telegram/SourceFiles/intro/intro.style b/Telegram/SourceFiles/intro/intro.style
index c9d4be939..26426f40d 100644
--- a/Telegram/SourceFiles/intro/intro.style
+++ b/Telegram/SourceFiles/intro/intro.style
@@ -174,6 +174,7 @@ introQrTitle: FlatLabel(defaultFlatLabel) {
 		linkFontOver: font(20px semibold underline);
 	}
 }
+introQrErrorTop: 336px;
 introQrTitleTop: 196px;
 introQrStep: defaultFlatLabel;
 introQrStepsTop: 232px;
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index 908aedc9a..2eb46ef52 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -56,7 +56,14 @@ namespace {
 	if (max > 0 && data.size * pixel > max) {
 		pixel = std::max(max / data.size, 1);
 	}
-	return TelegramQrExact(data, pixel * style::DevicePixelRatio());
+	const auto qr = TelegramQrExact(data, pixel * style::DevicePixelRatio());
+	auto result = QImage(qr.size(), QImage::Format_ARGB32_Premultiplied);
+	result.fill(st::windowBg->c);
+	{
+		auto p = QPainter(&result);
+		p.drawImage(QRect(QPoint(), qr.size()), qr);
+	}
+	return result;
 }
 
 [[nodiscard]] not_null<Ui::RpWidget*> PrepareQrWidget(
@@ -67,8 +74,10 @@ namespace {
 		: waiting(callback, st::defaultInfiniteRadialAnimation) {
 		}
 
+		QImage previous;
 		QImage qr;
 		QImage center;
+		Ui::Animations::Simple shown;
 		Ui::InfiniteRadialAnimation waiting;
 	};
 	auto qrs = std::move(
@@ -92,9 +101,15 @@ namespace {
 	) | rpl::map([](const Qr::Data &code, const auto &) {
 		return TelegramQr(code, st::introQrPixel, st::introQrMaxSize);
 	}) | rpl::start_with_next([=](QImage &&image) {
+		state->previous = std::move(state->qr);
 		state->qr = std::move(image);
 		state->waiting.stop();
-		result->update();
+		state->shown.stop();
+		state->shown.start(
+			[=] { result->update(); },
+			0.,
+			1.,
+			st::fadeWrapDuration);
 	}, result->lifetime());
 	std::move(
 		palettes
@@ -106,7 +121,24 @@ namespace {
 	result->paintRequest(
 	) | rpl::start_with_next([=](QRect clip) {
 		auto p = QPainter(result);
-		auto rect = QRect(
+		const auto shown = state->qr.isNull() ? 0. : state->shown.value(1.);
+		if (!state->qr.isNull()) {
+			const auto size = state->qr.size() / cIntRetinaFactor();
+			const auto qr = QRect(
+				(result->width() - size.width()) / 2,
+				(result->height() - size.height()) / 2,
+				size.width(),
+				size.height());
+			if (shown == 1.) {
+				state->previous = QImage();
+			} else if (!state->previous.isNull()) {
+				p.drawImage(qr, state->previous);
+			}
+			p.setOpacity(shown);
+			p.drawImage(qr, state->qr);
+			p.setOpacity(1.);
+		}
+		const auto rect = QRect(
 			(result->width() - st::introQrCenterSize) / 2,
 			(result->height() - st::introQrCenterSize) / 2,
 			st::introQrCenterSize,
@@ -119,7 +151,7 @@ namespace {
 			auto pen = st::activeButtonBg->p;
 			pen.setWidth(line);
 			pen.setCapStyle(Qt::RoundCap);
-			p.setOpacity(radial.shown);
+			p.setOpacity(radial.shown * (1. - shown));
 			p.setPen(pen);
 			p.drawArc(
 				rect.marginsAdded({ line, line, line, line }),
@@ -127,16 +159,6 @@ namespace {
 				radial.arcLength);
 			p.setOpacity(1.);
 		}
-		if (!state->qr.isNull()) {
-			const auto size = state->qr.size() / cIntRetinaFactor();
-			p.drawImage(
-				QRect(
-					(result->width() - size.width()) / 2,
-					(result->height() - size.height()) / 2,
-					size.width(),
-					size.height()),
-				state->qr);
-		}
 	}, result->lifetime());
 	return result;
 }
@@ -148,7 +170,7 @@ QrWidget::QrWidget(
 	not_null<Main::Account*> account,
 	not_null<Data*> data)
 : Step(parent, account, data)
-	, _refreshTimer([=] { refreshCode(); }) {
+, _refreshTimer([=] { refreshCode(); }) {
 	setTitleText(rpl::single(QString()));
 	setDescriptionText(rpl::single(QString()));
 	setErrorCentered(true);
@@ -163,6 +185,10 @@ QrWidget::QrWidget(
 	refreshCode();
 }
 
+int QrWidget::errorTop() const {
+	return contentTop() + st::introQrErrorTop;
+}
+
 void QrWidget::checkForTokenUpdate(const MTPUpdates &updates) {
 	updates.match([&](const MTPDupdateShort &data) {
 		checkForTokenUpdate(data.vupdate());
@@ -256,9 +282,7 @@ void QrWidget::setupControls() {
 			contentTop() + st::introQrSkipTop);
 	}, skip->lifetime());
 
-	skip->setClickedCallback([=] {
-		goNext<PhoneWidget>();
-	});
+	skip->setClickedCallback([=] { submit(); });
 }
 
 void QrWidget::refreshCode() {
diff --git a/Telegram/SourceFiles/intro/intro_qr.h b/Telegram/SourceFiles/intro/intro_qr.h
index fbcf1f5a9..0a97d263d 100644
--- a/Telegram/SourceFiles/intro/intro_qr.h
+++ b/Telegram/SourceFiles/intro/intro_qr.h
@@ -40,6 +40,8 @@ public:
 	}
 
 private:
+	int errorTop() const override;
+
 	void setupControls();
 	void refreshCode();
 	void checkForTokenUpdate(const MTPUpdates &updates);
diff --git a/Telegram/SourceFiles/intro/intro_step.cpp b/Telegram/SourceFiles/intro/intro_step.cpp
index 6afa818dc..0a5f3e2d3 100644
--- a/Telegram/SourceFiles/intro/intro_step.cpp
+++ b/Telegram/SourceFiles/intro/intro_step.cpp
@@ -179,11 +179,14 @@ void Step::updateLabelsPosition() {
 		}
 		Ui::SendPendingMoveResizeEvents(_error->entity());
 		auto errorLeft = _errorCentered ? 0 : (contentLeft() + st::buttonRadius);
-		auto errorTop = contentTop() + (_errorBelowLink ? st::introErrorBelowLinkTop : st::introErrorTop);
-		_error->moveToLeft(errorLeft, errorTop);
+		_error->moveToLeft(errorLeft, errorTop());
 	}
 }
 
+int Step::errorTop() const {
+	return contentTop() + st::introErrorTop;
+}
+
 void Step::setTitleText(rpl::producer<QString> titleText) {
 	_titleText = std::move(titleText);
 }
@@ -364,13 +367,6 @@ void Step::setErrorCentered(bool centered) {
 	_error.destroy();
 }
 
-void Step::setErrorBelowLink(bool below) {
-	_errorBelowLink = below;
-	if (_error) {
-		updateLabelsPosition();
-	}
-}
-
 void Step::showError(rpl::producer<QString> text) {
 	_errorText = std::move(text);
 }
diff --git a/Telegram/SourceFiles/intro/intro_step.h b/Telegram/SourceFiles/intro/intro_step.h
index 81ed97259..67e2ad225 100644
--- a/Telegram/SourceFiles/intro/intro_step.h
+++ b/Telegram/SourceFiles/intro/intro_step.h
@@ -78,7 +78,6 @@ public:
 	[[nodiscard]] int contentTop() const;
 
 	void setErrorCentered(bool centered);
-	void setErrorBelowLink(bool below);
 	void showError(rpl::producer<QString> text);
 	void hideError() {
 		showError(rpl::single(QString()));
@@ -128,6 +127,8 @@ protected:
 		}
 	}
 
+	virtual int errorTop() const;
+
 private:
 	struct CoverAnimation {
 		CoverAnimation() = default;
diff --git a/Telegram/SourceFiles/intro/introcode.cpp b/Telegram/SourceFiles/intro/introcode.cpp
index d8d6fce51..c8ba9ab8a 100644
--- a/Telegram/SourceFiles/intro/introcode.cpp
+++ b/Telegram/SourceFiles/intro/introcode.cpp
@@ -95,7 +95,6 @@ CodeWidget::CodeWidget(
 	_noTelegramCode->addClickHandler([=] { onNoTelegramCode(); });
 
 	_code->setDigitsCountMax(getData()->codeLength);
-	setErrorBelowLink(true);
 
 	setTitleText(rpl::single(App::formatPhone(getData()->phone)));
 	updateDescText();
@@ -107,6 +106,10 @@ void CodeWidget::refreshLang() {
 	updateControlsGeometry();
 }
 
+int CodeWidget::errorTop() const {
+	return contentTop() + st::introErrorBelowLinkTop;
+}
+
 void CodeWidget::updateDescText() {
 	const auto byTelegram = getData()->codeByTelegram;
 	setDescriptionText(
diff --git a/Telegram/SourceFiles/intro/introcode.h b/Telegram/SourceFiles/intro/introcode.h
index 5aaaeb352..d02ed7d82 100644
--- a/Telegram/SourceFiles/intro/introcode.h
+++ b/Telegram/SourceFiles/intro/introcode.h
@@ -69,6 +69,8 @@ private slots:
 	void onCheckRequest();
 
 private:
+	int errorTop() const override;
+
 	void updateCallText();
 	void refreshLang();
 	void updateControlsGeometry();
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.cpp b/Telegram/SourceFiles/intro/intropwdcheck.cpp
index db2e807b2..0e5bad618 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.cpp
+++ b/Telegram/SourceFiles/intro/intropwdcheck.cpp
@@ -50,7 +50,6 @@ PwdCheckWidget::PwdCheckWidget(
 
 	setTitleText(tr::lng_signin_title());
 	updateDescriptionText();
-	setErrorBelowLink(true);
 
 	if (_hint.isEmpty()) {
 		_pwdHint->hide();
@@ -79,6 +78,10 @@ void PwdCheckWidget::refreshLang() {
 	updateControlsGeometry();
 }
 
+int PwdCheckWidget::errorTop() const {
+	return contentTop() + st::introErrorBelowLinkTop;
+}
+
 void PwdCheckWidget::resizeEvent(QResizeEvent *e) {
 	Step::resizeEvent(e);
 	updateControlsGeometry();
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.h b/Telegram/SourceFiles/intro/intropwdcheck.h
index 5113781b5..02e392eae 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.h
+++ b/Telegram/SourceFiles/intro/intropwdcheck.h
@@ -46,6 +46,8 @@ private slots:
 	void onCheckRequest();
 
 private:
+	int errorTop() const override;
+
 	void showReset();
 	void refreshLang();
 	void updateControlsGeometry();
diff --git a/Telegram/SourceFiles/intro/introwidget.cpp b/Telegram/SourceFiles/intro/introwidget.cpp
index 98b6d5524..493c8913a 100644
--- a/Telegram/SourceFiles/intro/introwidget.cpp
+++ b/Telegram/SourceFiles/intro/introwidget.cpp
@@ -122,7 +122,7 @@ void Widget::createLanguageLink() {
 			Lang::CurrentCloudManager().switchToLanguage(languageId);
 		});
 		_changeLanguage->toggle(
-			!_resetAccount && !_terms,
+			!_resetAccount && !_terms && _nextShown,
 			anim::type::normal);
 		updateControlsGeometry();
 	};
@@ -230,11 +230,6 @@ void Widget::historyMove(Direction direction) {
 	setupNextButton();
 	if (_resetAccount) _resetAccount->show(anim::type::normal);
 	if (_terms) _terms->show(anim::type::normal);
-	if (_changeLanguage) {
-		_changeLanguage->toggle(
-			!_resetAccount && !_terms,
-			anim::type::normal);
-	}
 	getStep()->showAnimated(direction);
 	fixOrder();
 }
@@ -253,6 +248,7 @@ void Widget::hideAndDestroy(object_ptr<Ui::FadeWrap<Ui::RpWidget>> widget) {
 void Widget::fixOrder() {
 	_next->raise();
 	if (_update) _update->raise();
+	if (_changeLanguage) _changeLanguage->raise();
 	_settings->raise();
 	_back->raise();
 	_connecting->raise();
@@ -333,7 +329,7 @@ void Widget::showTerms() {
 	}
 	if (_changeLanguage) {
 		_changeLanguage->toggle(
-			!_terms && !_resetAccount,
+			!_terms && !_resetAccount && _nextShown,
 			anim::type::normal);
 	}
 }
@@ -491,7 +487,7 @@ void Widget::showControls() {
 	}
 	if (_changeLanguage) {
 		_changeLanguage->toggle(
-			!_resetAccount && !_terms,
+			!_resetAccount && !_terms && _nextShown,
 			anim::type::instant);
 	}
 	if (_terms) {
@@ -508,12 +504,19 @@ void Widget::setupNextButton() {
 	auto visible = getStep()->nextButtonText(
 	) | rpl::map([](const QString &text) {
 		return !text.isEmpty();
-	}) | rpl::distinct_until_changed();
+	});
 	std::move(
 		visible
-	) | rpl::start_with_next([=](bool visible) {
+	) | rpl::filter([=](bool visible) {
+		return visible != _nextShown;
+	}) | rpl::start_with_next([=](bool visible) {
 		_next->toggle(visible, anim::type::normal);
 		_nextShown = visible;
+		if (_changeLanguage) {
+			_changeLanguage->toggle(
+				!_resetAccount && !_terms && _nextShown,
+				anim::type::normal);
+		}
 		_nextShownAnimation.start(
 			[=] { updateControlsGeometry(); },
 			_nextShown ? 0. : 1.,
diff --git a/Telegram/SourceFiles/intro/introwidget.h b/Telegram/SourceFiles/intro/introwidget.h
index f56f984df..e9a84f541 100644
--- a/Telegram/SourceFiles/intro/introwidget.h
+++ b/Telegram/SourceFiles/intro/introwidget.h
@@ -152,7 +152,7 @@ private:
 
 	std::unique_ptr<Window::ConnectionState> _connecting;
 
-	bool _nextShown = false;
+	bool _nextShown = true;
 	Ui::Animations::Simple _nextShownAnimation;
 
 	mtpRequestId _resetRequest = 0;

From e943264823ed1f210acbb6a8dc38cadbc7dae074 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 27 Nov 2019 11:02:56 +0300
Subject: [PATCH 59/91] Pass MTP::Instance to MTP::Sender.

---
 Telegram/SourceFiles/apiwrap.cpp              |  4 +-
 .../SourceFiles/boxes/add_contact_box.cpp     | 15 +--
 Telegram/SourceFiles/boxes/add_contact_box.h  |  3 +-
 Telegram/SourceFiles/boxes/background_box.cpp |  9 +-
 Telegram/SourceFiles/boxes/edit_privacy_box.h |  2 +-
 Telegram/SourceFiles/boxes/passcode_box.cpp   | 23 +++--
 Telegram/SourceFiles/boxes/passcode_box.h     |  3 +-
 .../boxes/peer_list_controllers.cpp           |  5 +-
 .../SourceFiles/boxes/peer_list_controllers.h |  5 +-
 .../boxes/peers/add_participants_box.cpp      | 10 +-
 .../boxes/peers/add_participants_box.h        |  8 +-
 .../boxes/peers/edit_participants_box.cpp     | 12 ++-
 .../boxes/peers/edit_participants_box.h       |  7 +-
 .../boxes/peers/edit_peer_info_box.cpp        | 23 +++--
 .../boxes/peers/edit_peer_type_box.cpp        | 12 +--
 Telegram/SourceFiles/boxes/rate_call_box.cpp  |  3 +-
 Telegram/SourceFiles/boxes/rate_call_box.h    |  3 +-
 .../SourceFiles/boxes/self_destruction_box.h  |  2 +-
 Telegram/SourceFiles/boxes/sessions_box.cpp   | 12 ++-
 Telegram/SourceFiles/boxes/sessions_box.h     |  3 +-
 .../SourceFiles/boxes/sticker_set_box.cpp     |  7 +-
 Telegram/SourceFiles/boxes/stickers_box.cpp   |  8 +-
 Telegram/SourceFiles/boxes/stickers_box.h     |  4 +-
 .../calls/calls_box_controller.cpp            |  6 +-
 .../SourceFiles/calls/calls_box_controller.h  |  6 +-
 Telegram/SourceFiles/calls/calls_call.cpp     | 15 +--
 Telegram/SourceFiles/calls/calls_call.h       |  3 +-
 Telegram/SourceFiles/calls/calls_instance.cpp | 13 ++-
 Telegram/SourceFiles/calls/calls_instance.h   |  4 +-
 .../chat_helpers/gifs_list_widget.cpp         | 10 +-
 .../chat_helpers/gifs_list_widget.h           |  5 +-
 .../chat_helpers/stickers_list_widget.cpp     | 17 ++--
 .../chat_helpers/stickers_list_widget.h       |  4 +-
 Telegram/SourceFiles/core/application.cpp     |  9 +-
 Telegram/SourceFiles/core/application.h       |  2 +-
 .../data/data_search_controller.cpp           | 13 ++-
 .../SourceFiles/data/data_search_controller.h | 10 +-
 .../admin_log/history_admin_log_inner.cpp     | 11 ++-
 .../admin_log/history_admin_log_inner.h       |  9 +-
 .../info_common_groups_inner_widget.cpp       | 12 +--
 Telegram/SourceFiles/info/info_controller.cpp |  2 +-
 .../inline_bots/inline_results_widget.cpp     | 12 ++-
 .../inline_bots/inline_results_widget.h       |  3 +-
 Telegram/SourceFiles/intro/intro_qr.cpp       |  2 +-
 Telegram/SourceFiles/intro/intro_qr.h         |  2 +-
 Telegram/SourceFiles/intro/intro_step.h       |  1 -
 Telegram/SourceFiles/intro/introphone.cpp     |  2 -
 Telegram/SourceFiles/intro/intropwdcheck.cpp  | 20 ++--
 Telegram/SourceFiles/intro/intropwdcheck.h    |  3 +-
 Telegram/SourceFiles/intro/introstart.cpp     |  2 +
 Telegram/SourceFiles/intro/introwidget.cpp    | 76 +++++++++------
 Telegram/SourceFiles/intro/introwidget.h      |  9 +-
 .../SourceFiles/lang/lang_cloud_manager.cpp   | 96 ++++++++++++++-----
 .../SourceFiles/lang/lang_cloud_manager.h     | 14 ++-
 Telegram/SourceFiles/main/main_account.cpp    |  4 +-
 .../media_streaming_loader_mtproto.cpp        |  9 +-
 .../media_streaming_loader_mtproto.h          |  2 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  2 +-
 Telegram/SourceFiles/mtproto/sender.h         | 22 ++---
 .../passport/passport_form_controller.cpp     | 42 ++++----
 .../passport/passport_form_controller.h       |  3 +-
 .../settings/settings_privacy_controllers.cpp |  5 +-
 .../settings/settings_privacy_controllers.h   |  4 +-
 .../SourceFiles/support/support_helper.cpp    |  9 +-
 Telegram/SourceFiles/support/support_helper.h |  3 +-
 65 files changed, 406 insertions(+), 275 deletions(-)

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index df32f7241..9cb0a8f54 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -40,6 +40,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 //#include "history/feed/history_feed_section.h" // #feed
 #include "storage/localstorage.h"
 #include "main/main_session.h"
+#include "main/main_account.h"
 #include "boxes/confirm_box.h"
 #include "boxes/stickers_box.h"
 #include "boxes/sticker_set_box.h"
@@ -222,7 +223,8 @@ bool ApiWrap::BlockedUsersSlice::operator!=(const BlockedUsersSlice &other) cons
 }
 
 ApiWrap::ApiWrap(not_null<Main::Session*> session)
-: _session(session)
+: MTP::Sender(session->account().mtp())
+, _session(session)
 , _messageDataResolveDelayed([=] { resolveMessageDatas(); })
 , _webPagesTimer([=] { resolveWebPages(); })
 , _draftsSaveTimer([=] { saveDraftsToCloud(); })
diff --git a/Telegram/SourceFiles/boxes/add_contact_box.cpp b/Telegram/SourceFiles/boxes/add_contact_box.cpp
index ed831de5f..06e10fc37 100644
--- a/Telegram/SourceFiles/boxes/add_contact_box.cpp
+++ b/Telegram/SourceFiles/boxes/add_contact_box.cpp
@@ -203,7 +203,7 @@ void ShowAddParticipantsError(
 	Ui::show(Box<InformBox>(text), Ui::LayerOption::KeepOther);
 }
 
-class RevokePublicLinkBox::Inner : public TWidget, private MTP::Sender {
+class RevokePublicLinkBox::Inner : public TWidget {
 public:
 	Inner(
 		QWidget *parent,
@@ -228,6 +228,7 @@ private:
 	void updateSelected();
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	PeerData *_selected = nullptr;
 	PeerData *_pressed = nullptr;
@@ -450,6 +451,7 @@ GroupInfoBox::GroupInfoBox(
 	const QString &title,
 	Fn<void(not_null<ChannelData*>)> channelDone)
 : _navigation(navigation)
+, _api(_navigation->session().api().instance())
 , _type(type)
 , _initialTitle(title)
 , _channelDone(std::move(channelDone)) {
@@ -569,7 +571,7 @@ void GroupInfoBox::createGroup(
 	if (inputs.empty()) {
 		return;
 	}
-	_creationRequestId = request(MTPmessages_CreateChat(
+	_creationRequestId = _api.request(MTPmessages_CreateChat(
 		MTP_vector<MTPInputUser>(inputs),
 		MTP_string(title)
 	)).done([=](const MTPUpdates &result) {
@@ -645,7 +647,7 @@ void GroupInfoBox::createChannel(const QString &title, const QString &descriptio
 	const auto flags = (_type == Type::Megagroup)
 		? MTPchannels_CreateChannel::Flag::f_megagroup
 		: MTPchannels_CreateChannel::Flag::f_broadcast;
-	_creationRequestId = request(MTPchannels_CreateChannel(
+	_creationRequestId = _api.request(MTPchannels_CreateChannel(
 		MTP_flags(flags),
 		MTP_string(title),
 		MTP_string(description),
@@ -682,7 +684,7 @@ void GroupInfoBox::createChannel(const QString &title, const QString &descriptio
 						std::move(image));
 				}
 				_createdChannel = channel;
-				_creationRequestId = request(MTPmessages_ExportChatInvite(
+				_creationRequestId = _api.request(MTPmessages_ExportChatInvite(
 					_createdChannel->input
 				)).done([=](const MTPExportedChatInvite &result) {
 					_creationRequestId = 0;
@@ -1287,6 +1289,7 @@ RevokePublicLinkBox::Inner::Inner(
 	Fn<void()> revokeCallback)
 : TWidget(parent)
 , _session(session)
+, _api(_session->api().instance())
 , _rowHeight(st::contactsPadding.top() + st::contactsPhotoSize + st::contactsPadding.bottom())
 , _revokeWidth(st::normalFont->width(tr::lng_channels_too_much_public_revoke(tr::now)))
 , _revokeCallback(std::move(revokeCallback)) {
@@ -1294,7 +1297,7 @@ RevokePublicLinkBox::Inner::Inner(
 
 	resize(width(), 5 * _rowHeight);
 
-	request(MTPchannels_GetAdminedPublicChannels(
+	_api.request(MTPchannels_GetAdminedPublicChannels(
 		MTP_flags(0)
 	)).done([=](const MTPmessages_Chats &result) {
 		const auto &chats = result.match([](const auto &data) {
@@ -1401,7 +1404,7 @@ void RevokePublicLinkBox::Inner::mouseReleaseEvent(QMouseEvent *e) {
 		auto confirmText = tr::lng_channels_too_much_public_revoke(tr::now);
 		_weakRevokeConfirmBox = Ui::show(Box<ConfirmBox>(text, confirmText, crl::guard(this, [this, pressed]() {
 			if (_revokeRequestId) return;
-			_revokeRequestId = request(MTPchannels_UpdateUsername(
+			_revokeRequestId = _api.request(MTPchannels_UpdateUsername(
 				pressed->asChannel()->inputChannel,
 				MTP_string()
 			)).done([=](const MTPBool &result) {
diff --git a/Telegram/SourceFiles/boxes/add_contact_box.h b/Telegram/SourceFiles/boxes/add_contact_box.h
index e97eff55e..488893da8 100644
--- a/Telegram/SourceFiles/boxes/add_contact_box.h
+++ b/Telegram/SourceFiles/boxes/add_contact_box.h
@@ -94,7 +94,7 @@ private:
 
 };
 
-class GroupInfoBox : public Ui::BoxContent, private MTP::Sender {
+class GroupInfoBox : public Ui::BoxContent {
 public:
 	enum class Type {
 		Group,
@@ -124,6 +124,7 @@ private:
 	void updateMaxHeight();
 
 	const not_null<Window::SessionNavigation*> _navigation;
+	MTP::Sender _api;
 
 	Type _type = Type::Group;
 	QString _initialTitle;
diff --git a/Telegram/SourceFiles/boxes/background_box.cpp b/Telegram/SourceFiles/boxes/background_box.cpp
index 9d91c177a..f69aac5db 100644
--- a/Telegram/SourceFiles/boxes/background_box.cpp
+++ b/Telegram/SourceFiles/boxes/background_box.cpp
@@ -53,10 +53,7 @@ QImage TakeMiddleSample(QImage original, QSize size) {
 
 } // namespace
 
-class BackgroundBox::Inner
-	: public Ui::RpWidget
-	, private MTP::Sender
-	, private base::Subscriber {
+class BackgroundBox::Inner : public Ui::RpWidget, private base::Subscriber {
 public:
 	Inner(
 		QWidget *parent,
@@ -114,6 +111,7 @@ private:
 	void validatePaperThumbnail(const Paper &paper) const;
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	std::vector<Paper> _papers;
 
@@ -185,6 +183,7 @@ BackgroundBox::Inner::Inner(
 	not_null<Main::Session*> session)
 : RpWidget(parent)
 , _session(session)
+, _api(_session->api().instance())
 , _check(std::make_unique<Ui::RoundCheckbox>(st::overviewCheck, [=] { update(); })) {
 	_check->setChecked(true, Ui::RoundCheckbox::SetStyle::Fast);
 	if (_session->data().wallpapers().empty()) {
@@ -209,7 +208,7 @@ BackgroundBox::Inner::Inner(
 }
 
 void BackgroundBox::Inner::requestPapers() {
-	request(MTPaccount_GetWallPapers(
+	_api.request(MTPaccount_GetWallPapers(
 		MTP_int(_session->data().wallpapersHash())
 	)).done([=](const MTPaccount_WallPapers &result) {
 		if (_session->data().updateWallpapers(result)) {
diff --git a/Telegram/SourceFiles/boxes/edit_privacy_box.h b/Telegram/SourceFiles/boxes/edit_privacy_box.h
index 1060157fd..4310d1b51 100644
--- a/Telegram/SourceFiles/boxes/edit_privacy_box.h
+++ b/Telegram/SourceFiles/boxes/edit_privacy_box.h
@@ -100,7 +100,7 @@ private:
 
 };
 
-class EditPrivacyBox : public Ui::BoxContent, private MTP::Sender {
+class EditPrivacyBox : public Ui::BoxContent {
 public:
 	using Value = ApiWrap::Privacy;
 	using Option = Value::Option;
diff --git a/Telegram/SourceFiles/boxes/passcode_box.cpp b/Telegram/SourceFiles/boxes/passcode_box.cpp
index 26a073c50..96ce5c731 100644
--- a/Telegram/SourceFiles/boxes/passcode_box.cpp
+++ b/Telegram/SourceFiles/boxes/passcode_box.cpp
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/confirm_box.h"
 #include "boxes/confirm_phone_box.h"
 #include "mainwindow.h"
+#include "apiwrap.h"
 #include "main/main_session.h"
 #include "storage/localstorage.h"
 #include "ui/widgets/buttons.h"
@@ -47,6 +48,7 @@ PasscodeBox::PasscodeBox(
 	not_null<Main::Session*> session,
 	bool turningOff)
 : _session(session)
+, _api(_session->api().instance())
 , _turningOff(turningOff)
 , _about(st::boxWidth - st::boxPadding.left() * 1.5)
 , _oldPasscode(this, st::defaultInputField, tr::lng_passcode_enter_old())
@@ -62,6 +64,7 @@ PasscodeBox::PasscodeBox(
 	not_null<Main::Session*> session,
 	const CloudFields &fields)
 : _session(session)
+, _api(_session->api().instance())
 , _turningOff(fields.turningOff)
 , _cloudPwd(true)
 , _cloudFields(fields)
@@ -357,7 +360,7 @@ void PasscodeBox::validateEmail(
 		if (_setRequest) {
 			return;
 		}
-		_setRequest = request(MTPaccount_ConfirmPasswordEmail(
+		_setRequest = _api.request(MTPaccount_ConfirmPasswordEmail(
 			MTP_string(code)
 		)).done([=](const MTPBool &result) {
 			*set = true;
@@ -387,7 +390,7 @@ void PasscodeBox::validateEmail(
 		if (_setRequest) {
 			return;
 		}
-		_setRequest = request(MTPaccount_ResendPasswordEmail(
+		_setRequest = _api.request(MTPaccount_ResendPasswordEmail(
 		)).done([=](const MTPBool &result) {
 			_setRequest = 0;
 			resent->fire(tr::lng_cloud_password_resent(tr::now));
@@ -597,8 +600,8 @@ void PasscodeBox::requestPasswordData() {
 		return serverError();
 	}
 
-	request(base::take(_setRequest)).cancel();
-	_setRequest = request(
+	_api.request(base::take(_setRequest)).cancel();
+	_setRequest = _api.request(
 		MTPaccount_GetPassword()
 	).done([=](const MTPaccount_Password &result) {
 		_setRequest = 0;
@@ -636,7 +639,7 @@ void PasscodeBox::sendClearCloudPassword(
 		| MTPDaccount_passwordInputSettings::Flag::f_new_password_hash
 		| MTPDaccount_passwordInputSettings::Flag::f_hint
 		| MTPDaccount_passwordInputSettings::Flag::f_email;
-	_setRequest = request(MTPaccount_UpdatePasswordSettings(
+	_setRequest = _api.request(MTPaccount_UpdatePasswordSettings(
 		check.result,
 		MTP_account_passwordInputSettings(
 			MTP_flags(flags),
@@ -667,7 +670,7 @@ void PasscodeBox::setNewCloudPassword(const QString &newPassword) {
 		| MTPDaccount_passwordInputSettings::Flag::f_hint
 		| MTPDaccount_passwordInputSettings::Flag::f_email;
 	_checkPasswordCallback = nullptr;
-	_setRequest = request(MTPaccount_UpdatePasswordSettings(
+	_setRequest = _api.request(MTPaccount_UpdatePasswordSettings(
 		MTP_inputCheckPasswordEmpty(),
 		MTP_account_passwordInputSettings(
 			MTP_flags(flags),
@@ -695,7 +698,7 @@ void PasscodeBox::changeCloudPassword(
 		const QString &oldPassword,
 		const Core::CloudPasswordResult &check,
 		const QString &newPassword) {
-	_setRequest = request(MTPaccount_GetPasswordSettings(
+	_setRequest = _api.request(MTPaccount_GetPasswordSettings(
 		check.result
 	)).done([=](const MTPaccount_PasswordSettings &result) {
 		_setRequest = 0;
@@ -760,7 +763,7 @@ void PasscodeBox::resetSecret(
 		const QString &newPassword,
 		Fn<void()> callback) {
 	using Flag = MTPDaccount_passwordInputSettings::Flag;
-	_setRequest = request(MTPaccount_UpdatePasswordSettings(
+	_setRequest = _api.request(MTPaccount_UpdatePasswordSettings(
 		check.result,
 		MTP_account_passwordInputSettings(
 			MTP_flags(Flag::f_new_secure_settings),
@@ -814,7 +817,7 @@ void PasscodeBox::sendChangeCloudPassword(
 				_cloudFields.newSecureSecretAlgo,
 				bytes::make_span(newPasswordBytes)));
 	}
-	_setRequest = request(MTPaccount_UpdatePasswordSettings(
+	_setRequest = _api.request(MTPaccount_UpdatePasswordSettings(
 		check.result,
 		MTP_account_passwordInputSettings(
 			MTP_flags(flags),
@@ -873,7 +876,7 @@ void PasscodeBox::emailChanged() {
 void PasscodeBox::recoverByEmail() {
 	if (_pattern.isEmpty()) {
 		_pattern = "-";
-		request(MTPauth_RequestPasswordRecovery(
+		_api.request(MTPauth_RequestPasswordRecovery(
 		)).done([=](const MTPauth_PasswordRecovery &result) {
 			recoverStarted(result);
 		}).fail([=](const RPCError &error) {
diff --git a/Telegram/SourceFiles/boxes/passcode_box.h b/Telegram/SourceFiles/boxes/passcode_box.h
index a8ad5ea8c..03ab68f87 100644
--- a/Telegram/SourceFiles/boxes/passcode_box.h
+++ b/Telegram/SourceFiles/boxes/passcode_box.h
@@ -25,7 +25,7 @@ namespace Core {
 struct CloudPasswordState;
 } // namespace Core
 
-class PasscodeBox : public Ui::BoxContent, private MTP::Sender {
+class PasscodeBox : public Ui::BoxContent {
 public:
 	PasscodeBox(QWidget*, not_null<Main::Session*> session, bool turningOff);
 
@@ -130,6 +130,7 @@ private:
 	void serverError();
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	QString _pattern;
 
diff --git a/Telegram/SourceFiles/boxes/peer_list_controllers.cpp b/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
index 190c2f372..606ecc4f4 100644
--- a/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
+++ b/Telegram/SourceFiles/boxes/peer_list_controllers.cpp
@@ -142,7 +142,8 @@ void PeerListRowWithLink::paintAction(
 
 PeerListGlobalSearchController::PeerListGlobalSearchController(
 	not_null<Window::SessionNavigation*> navigation)
-: _navigation(navigation) {
+: _navigation(navigation)
+, _api(_navigation->session().api().instance()) {
 	_timer.setCallback([this] { searchOnServer(); });
 }
 
@@ -169,7 +170,7 @@ bool PeerListGlobalSearchController::searchInCache() {
 }
 
 void PeerListGlobalSearchController::searchOnServer() {
-	_requestId = request(MTPcontacts_Search(
+	_requestId = _api.request(MTPcontacts_Search(
 		MTP_string(_query),
 		MTP_int(SearchPeopleLimit)
 	)).done([=](const MTPcontacts_Found &result, mtpRequestId requestId) {
diff --git a/Telegram/SourceFiles/boxes/peer_list_controllers.h b/Telegram/SourceFiles/boxes/peer_list_controllers.h
index ddc4ba4f8..a1a52e701 100644
--- a/Telegram/SourceFiles/boxes/peer_list_controllers.h
+++ b/Telegram/SourceFiles/boxes/peer_list_controllers.h
@@ -59,9 +59,7 @@ private:
 
 };
 
-class PeerListGlobalSearchController
-	: public PeerListSearchController
-	, private MTP::Sender {
+class PeerListGlobalSearchController : public PeerListSearchController {
 public:
 	PeerListGlobalSearchController(
 		not_null<Window::SessionNavigation*> navigation);
@@ -78,6 +76,7 @@ private:
 	void searchDone(const MTPcontacts_Found &result, mtpRequestId requestId);
 
 	const not_null<Window::SessionNavigation*> _navigation;
+	MTP::Sender _api;
 	base::Timer _timer;
 	QString _query;
 	mtpRequestId _requestId = 0;
diff --git a/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
index 08c95bc72..ff7d2c3d1 100644
--- a/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/add_participants_box.cpp
@@ -276,6 +276,7 @@ AddSpecialBoxController::AddSpecialBoxController(
 	peer,
 	&_additional))
 , _peer(peer)
+, _api(_peer->session().api().instance())
 , _role(role)
 , _additional(peer, Role::Members)
 , _adminDoneCallback(std::move(adminDoneCallback))
@@ -408,7 +409,7 @@ void AddSpecialBoxController::loadMoreRows() {
 	const auto participantsHash = 0;
 	const auto channel = _peer->asChannel();
 
-	_loadRequestId = request(MTPchannels_GetParticipants(
+	_loadRequestId = _api.request(MTPchannels_GetParticipants(
 		channel->inputChannel,
 		MTP_channelParticipantsRecent(),
 		MTP_int(_offset),
@@ -464,7 +465,7 @@ bool AddSpecialBoxController::checkInfoLoaded(
 
 	// We don't know what this user status is in the group.
 	const auto channel = _peer->asChannel();
-	request(MTPchannels_GetParticipant(
+	_api.request(MTPchannels_GetParticipant(
 		channel->inputChannel,
 		user->inputUser
 	)).done([=](const MTPchannels_ChannelParticipant &result) {
@@ -829,6 +830,7 @@ AddSpecialBoxSearchController::AddSpecialBoxSearchController(
 	not_null<ParticipantsAdditionalData*> additional)
 : _peer(peer)
 , _additional(additional)
+, _api(_peer->session().api().instance())
 , _timer([=] { searchOnServer(); }) {
 	subscribeToMigration();
 }
@@ -924,7 +926,7 @@ void AddSpecialBoxSearchController::requestParticipants() {
 	const auto participantsHash = 0;
 	const auto channel = _peer->asChannel();
 
-	_requestId = request(MTPchannels_GetParticipants(
+	_requestId = _api.request(MTPchannels_GetParticipants(
 		channel->inputChannel,
 		MTP_channelParticipantsSearch(MTP_string(_query)),
 		MTP_int(_offset),
@@ -1012,7 +1014,7 @@ void AddSpecialBoxSearchController::requestGlobal() {
 	}
 
 	auto perPage = SearchPeopleLimit;
-	_requestId = request(MTPcontacts_Search(
+	_requestId = _api.request(MTPcontacts_Search(
 		MTP_string(_query),
 		MTP_int(perPage)
 	)).done([=](const MTPcontacts_Found &result, mtpRequestId requestId) {
diff --git a/Telegram/SourceFiles/boxes/peers/add_participants_box.h b/Telegram/SourceFiles/boxes/peers/add_participants_box.h
index d15f474e8..2761d172d 100644
--- a/Telegram/SourceFiles/boxes/peers/add_participants_box.h
+++ b/Telegram/SourceFiles/boxes/peers/add_participants_box.h
@@ -69,7 +69,6 @@ private:
 class AddSpecialBoxController
 	: public PeerListController
 	, private base::Subscriber
-	, private MTP::Sender
 	, public base::has_weak_ptr {
 public:
 	using Role = ParticipantsBoxController::Role;
@@ -87,12 +86,12 @@ public:
 		AdminDoneCallback adminDoneCallback,
 		BannedDoneCallback bannedDoneCallback);
 
-	Main::Session &session() const override;
+	[[nodiscard]] Main::Session &session() const override;
 	void prepare() override;
 	void rowClicked(not_null<PeerListRow*> row) override;
 	void loadMoreRows() override;
 
-	std::unique_ptr<PeerListRow> createSearchRow(
+	[[nodiscard]] std::unique_ptr<PeerListRow> createSearchRow(
 		not_null<PeerData*> peer) override;
 
 private:
@@ -120,6 +119,7 @@ private:
 	void migrate(not_null<ChannelData*> channel);
 
 	not_null<PeerData*> _peer;
+	MTP::Sender _api;
 	Role _role = Role::Admins;
 	int _offset = 0;
 	mtpRequestId _loadRequestId = 0;
@@ -139,7 +139,6 @@ protected:
 // Finds chat/channel members, then contacts, then global search results.
 class AddSpecialBoxSearchController
 	: public PeerListSearchController
-	, private MTP::Sender
 	, private base::Subscriber {
 public:
 	using Role = ParticipantsBoxController::Role;
@@ -181,6 +180,7 @@ private:
 
 	not_null<PeerData*> _peer;
 	not_null<ParticipantsAdditionalData*> _additional;
+	MTP::Sender _api;
 
 	base::Timer _timer;
 	QString _query;
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
index 892b5a6a6..f250ca81f 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.cpp
@@ -745,6 +745,7 @@ ParticipantsBoxController::ParticipantsBoxController(
 : PeerListController(CreateSearchController(peer, role, &_additional))
 , _navigation(navigation)
 , _peer(peer)
+, _api(_peer->session().api().instance())
 , _role(role)
 , _additional(peer, _role) {
 	subscribeToMigration();
@@ -1022,7 +1023,7 @@ void ParticipantsBoxController::restoreState(
 		: nullptr;
 	if (const auto my = dynamic_cast<SavedState*>(typeErasedState)) {
 		if (const auto requestId = base::take(_loadRequestId)) {
-			request(requestId).cancel();
+			_api.request(requestId).cancel();
 		}
 
 		_additional = std::move(my->additional);
@@ -1251,7 +1252,7 @@ void ParticipantsBoxController::loadMoreRows() {
 		: kParticipantsFirstPageCount;
 	const auto participantsHash = 0;
 
-	_loadRequestId = request(MTPchannels_GetParticipants(
+	_loadRequestId = _api.request(MTPchannels_GetParticipants(
 		channel->inputChannel,
 		filter,
 		MTP_int(_offset),
@@ -1906,7 +1907,8 @@ ParticipantsBoxSearchController::ParticipantsBoxSearchController(
 	not_null<ParticipantsAdditionalData*> additional)
 : _channel(channel)
 , _role(role)
-, _additional(additional) {
+, _additional(additional)
+, _api(_channel->session().api().instance()) {
 	_timer.setCallback([=] { searchOnServer(); });
 }
 
@@ -1938,7 +1940,7 @@ void ParticipantsBoxSearchController::restoreState(
 		std::unique_ptr<SavedStateBase> state) {
 	if (auto my = dynamic_cast<SavedState*>(state.get())) {
 		if (auto requestId = base::take(_requestId)) {
-			request(requestId).cancel();
+			_api.request(requestId).cancel();
 		}
 		_cache.clear();
 		_queries.clear();
@@ -2002,7 +2004,7 @@ bool ParticipantsBoxSearchController::loadMoreRows() {
 	auto perPage = kParticipantsPerPage;
 	auto participantsHash = 0;
 
-	_requestId = request(MTPchannels_GetParticipants(
+	_requestId = _api.request(MTPchannels_GetParticipants(
 		_channel->inputChannel,
 		filter,
 		MTP_int(_offset),
diff --git a/Telegram/SourceFiles/boxes/peers/edit_participants_box.h b/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
index af0b8decc..fd36c97ce 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
+++ b/Telegram/SourceFiles/boxes/peers/edit_participants_box.h
@@ -134,7 +134,6 @@ private:
 class ParticipantsBoxController
 	: public PeerListController
 	, private base::Subscriber
-	, private MTP::Sender
 	, public base::has_weak_ptr {
 public:
 	using Role = ParticipantsRole;
@@ -238,6 +237,7 @@ private:
 
 	not_null<Window::SessionNavigation*> _navigation;
 	not_null<PeerData*> _peer;
+	MTP::Sender _api;
 	Role _role = Role::Admins;
 	int _offset = 0;
 	mtpRequestId _loadRequestId = 0;
@@ -251,9 +251,7 @@ private:
 };
 
 // Members, banned and restricted users server side search.
-class ParticipantsBoxSearchController
-	: public PeerListSearchController
-	, private MTP::Sender {
+class ParticipantsBoxSearchController : public PeerListSearchController {
 public:
 	using Role = ParticipantsBoxController::Role;
 
@@ -295,6 +293,7 @@ private:
 	not_null<ChannelData*> _channel;
 	Role _role = Role::Restricted;
 	not_null<ParticipantsAdditionalData*> _additional;
+	MTP::Sender _api;
 
 	base::Timer _timer;
 	QString _query;
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
index c84e6be4e..7dd7e538f 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_info_box.cpp
@@ -240,9 +240,7 @@ namespace {
 constexpr auto kMaxGroupChannelTitle = 128; // See also add_contact_box.
 constexpr auto kMaxChannelDescription = 255; // See also add_contact_box.
 
-class Controller
-	: public base::has_weak_ptr
-	, private MTP::Sender {
+class Controller : public base::has_weak_ptr {
 public:
 	Controller(
 		not_null<Window::SessionNavigation*> navigation,
@@ -334,6 +332,7 @@ private:
 	const not_null<Window::SessionNavigation*> _navigation;
 	const not_null<Ui::BoxContent*> _box;
 	not_null<PeerData*> _peer;
+	MTP::Sender _api;
 	const bool _isGroup = false;
 
 	base::unique_qptr<Ui::VerticalLayout> _wrap;
@@ -344,7 +343,6 @@ private:
 
 	const rpl::event_stream<Privacy> _privacyTypeUpdates;
 	const rpl::event_stream<ChannelData*> _linkedChatUpdates;
-	MTP::Sender _linkedChatsRequester;
 	mtpRequestId _linkedChatsRequestId = 0;
 
 	rpl::lifetime _lifetime;
@@ -358,6 +356,7 @@ Controller::Controller(
 : _navigation(navigation)
 , _box(box)
 , _peer(peer)
+, _api(_peer->session().api().instance())
 , _isGroup(_peer->isChat() || _peer->isMegagroup()) {
 	_box->setTitle(_isGroup
 		? tr::lng_edit_group()
@@ -644,7 +643,7 @@ void Controller::showEditLinkedChatBox() {
 		callback(_linkedChatOriginalValue);
 		return;
 	}
-	_linkedChatsRequestId = _linkedChatsRequester.request(
+	_linkedChatsRequestId = _api.request(
 		MTPchannels_GetGroupsForDiscussion()
 	).done([=](const MTPmessages_Chats &result) {
 		_linkedChatsRequestId = 0;
@@ -1187,7 +1186,7 @@ void Controller::saveUsername() {
 		return;
 	}
 
-	request(MTPchannels_UpdateUsername(
+	_api.request(MTPchannels_UpdateUsername(
 		channel->inputChannel,
 		MTP_string(*_savingData.username)
 	)).done([=](const MTPBool &result) {
@@ -1242,7 +1241,7 @@ void Controller::saveLinkedChat() {
 	const auto input = *_savingData.linkedChat
 		? (*_savingData.linkedChat)->inputChannel
 		: MTP_inputChannelEmpty();
-	request(MTPchannels_SetDiscussionGroup(
+	_api.request(MTPchannels_SetDiscussionGroup(
 		(channel->isBroadcast() ? channel->inputChannel : input),
 		(channel->isBroadcast() ? input : channel->inputChannel)
 	)).done([=](const MTPBool &result) {
@@ -1283,14 +1282,14 @@ void Controller::saveTitle() {
 	};
 
 	if (const auto channel = _peer->asChannel()) {
-		request(MTPchannels_EditTitle(
+		_api.request(MTPchannels_EditTitle(
 			channel->inputChannel,
 			MTP_string(*_savingData.title)
 		)).done(std::move(onDone)
 		).fail(std::move(onFail)
 		).send();
 	} else if (const auto chat = _peer->asChat()) {
-		request(MTPmessages_EditChatTitle(
+		_api.request(MTPmessages_EditChatTitle(
 			chat->inputChat,
 			MTP_string(*_savingData.title)
 		)).done(std::move(onDone)
@@ -1311,7 +1310,7 @@ void Controller::saveDescription() {
 		_peer->setAbout(*_savingData.description);
 		continueSave();
 	};
-	request(MTPmessages_EditChatAbout(
+	_api.request(MTPmessages_EditChatAbout(
 		_peer->input,
 		MTP_string(*_savingData.description)
 	)).done([=](const MTPBool &result) {
@@ -1368,7 +1367,7 @@ void Controller::togglePreHistoryHidden(
 
 		done();
 	};
-	request(MTPchannels_TogglePreHistoryHidden(
+	_api.request(MTPchannels_TogglePreHistoryHidden(
 		channel->inputChannel,
 		MTP_bool(hidden)
 	)).done([=](const MTPUpdates &result) {
@@ -1390,7 +1389,7 @@ void Controller::saveSignatures() {
 		|| *_savingData.signatures == channel->addsSignature()) {
 		return continueSave();
 	}
-	request(MTPchannels_ToggleSignatures(
+	_api.request(MTPchannels_ToggleSignatures(
 		channel->inputChannel,
 		MTP_bool(*_savingData.signatures)
 	)).done([=](const MTPUpdates &result) {
diff --git a/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp b/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
index 8dd0c2eaa..71ee082ca 100644
--- a/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
+++ b/Telegram/SourceFiles/boxes/peers/edit_peer_type_box.cpp
@@ -51,9 +51,7 @@ namespace {
 constexpr auto kUsernameCheckTimeout = crl::time(200);
 constexpr auto kMinUsernameLength = 5;
 
-class Controller
-	: public base::has_weak_ptr
-	, private MTP::Sender {
+class Controller : public base::has_weak_ptr {
 public:
 	Controller(
 		not_null<Ui::VerticalLayout*> container,
@@ -144,6 +142,7 @@ private:
 	QString inviteLinkText();
 
 	not_null<PeerData*> _peer;
+	MTP::Sender _api;
 	std::optional<Privacy> _privacySavedValue;
 	std::optional<QString> _usernameSavedValue;
 
@@ -169,6 +168,7 @@ Controller::Controller(
 	std::optional<Privacy> privacySavedValue,
 	std::optional<QString> usernameSavedValue)
 : _peer(peer)
+, _api(_peer->session().api().instance())
 , _privacySavedValue(privacySavedValue)
 , _usernameSavedValue(usernameSavedValue)
 , _useLocationPhrases(useLocationPhrases)
@@ -401,7 +401,7 @@ void Controller::privacyChanged(Privacy value) {
 		refreshVisibilities();
 		_controls.usernameInput->setDisplayFocused(true);
 	} else {
-		request(base::take(_checkUsernameRequestId)).cancel();
+		_api.request(base::take(_checkUsernameRequestId)).cancel();
 		_checkUsernameTimer.cancel();
 		refreshVisibilities();
 	}
@@ -420,11 +420,11 @@ void Controller::checkUsernameAvailability() {
 		return;
 	}
 	if (_checkUsernameRequestId) {
-		request(_checkUsernameRequestId).cancel();
+		_api.request(_checkUsernameRequestId).cancel();
 	}
 	const auto channel = _peer->migrateToOrMe()->asChannel();
 	const auto username = channel ? channel->username : QString();
-	_checkUsernameRequestId = request(MTPchannels_CheckUsername(
+	_checkUsernameRequestId = _api.request(MTPchannels_CheckUsername(
 		channel ? channel->inputChannel : MTP_inputChannelEmpty(),
 		MTP_string(checking)
 	)).done([=](const MTPBool &result) {
diff --git a/Telegram/SourceFiles/boxes/rate_call_box.cpp b/Telegram/SourceFiles/boxes/rate_call_box.cpp
index be102184b..85294a3fe 100644
--- a/Telegram/SourceFiles/boxes/rate_call_box.cpp
+++ b/Telegram/SourceFiles/boxes/rate_call_box.cpp
@@ -31,6 +31,7 @@ RateCallBox::RateCallBox(
 	uint64 callId,
 	uint64 callAccessHash)
 : _session(session)
+, _api(_session->api().instance())
 , _callId(callId)
 , _callAccessHash(callAccessHash) {
 }
@@ -120,7 +121,7 @@ void RateCallBox::send() {
 		return;
 	}
 	auto comment = _comment ? _comment->getLastText().trimmed() : QString();
-	_requestId = request(MTPphone_SetCallRating(
+	_requestId = _api.request(MTPphone_SetCallRating(
 		MTP_flags(0),
 		MTP_inputPhoneCall(MTP_long(_callId), MTP_long(_callAccessHash)),
 		MTP_int(_rating),
diff --git a/Telegram/SourceFiles/boxes/rate_call_box.h b/Telegram/SourceFiles/boxes/rate_call_box.h
index 9efaa4d53..99ca677d8 100644
--- a/Telegram/SourceFiles/boxes/rate_call_box.h
+++ b/Telegram/SourceFiles/boxes/rate_call_box.h
@@ -20,7 +20,7 @@ namespace Main {
 class Session;
 } // namespace Main
 
-class RateCallBox : public Ui::BoxContent, private MTP::Sender {
+class RateCallBox : public Ui::BoxContent {
 public:
 	RateCallBox(
 		QWidget*,
@@ -41,6 +41,7 @@ private:
 	void commentResized();
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	uint64 _callId = 0;
 	uint64 _callAccessHash = 0;
diff --git a/Telegram/SourceFiles/boxes/self_destruction_box.h b/Telegram/SourceFiles/boxes/self_destruction_box.h
index 475f59749..95f7928c8 100644
--- a/Telegram/SourceFiles/boxes/self_destruction_box.h
+++ b/Telegram/SourceFiles/boxes/self_destruction_box.h
@@ -20,7 +20,7 @@ namespace Main {
 class Session;
 } // namespace Main
 
-class SelfDestructionBox : public Ui::BoxContent, private MTP::Sender {
+class SelfDestructionBox : public Ui::BoxContent {
 public:
 	SelfDestructionBox(
 		QWidget*,
diff --git a/Telegram/SourceFiles/boxes/sessions_box.cpp b/Telegram/SourceFiles/boxes/sessions_box.cpp
index 91247790d..071058b17 100644
--- a/Telegram/SourceFiles/boxes/sessions_box.cpp
+++ b/Telegram/SourceFiles/boxes/sessions_box.cpp
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/localstorage.h"
 #include "mainwidget.h"
 #include "mainwindow.h"
+#include "apiwrap.h"
 #include "main/main_session.h"
 #include "data/data_session.h"
 #include "base/unixtime.h"
@@ -77,6 +78,7 @@ private:
 
 SessionsBox::SessionsBox(QWidget*, not_null<Main::Session*> session)
 : _session(session)
+, _api(_session->api().instance())
 , _shortPollTimer([=] { shortPollSessions(); }) {
 }
 
@@ -280,7 +282,7 @@ void SessionsBox::shortPollSessions() {
 	if (_shortPollRequest) {
 		return;
 	}
-	_shortPollRequest = request(MTPaccount_GetAuthorizations(
+	_shortPollRequest = _api.request(MTPaccount_GetAuthorizations(
 	)).done([=](const MTPaccount_Authorizations &result) {
 		got(result);
 	}).send();
@@ -294,7 +296,7 @@ void SessionsBox::terminateOne(uint64 hash) {
 			_terminateBox->closeBox();
 			_terminateBox = nullptr;
 		}
-		request(MTPaccount_ResetAuthorization(
+		_api.request(MTPaccount_ResetAuthorization(
 			MTP_long(hash)
 		)).done([=](const MTPBool &result) {
 			_inner->terminatingOne(hash, false);
@@ -330,12 +332,12 @@ void SessionsBox::terminateAll() {
 			_terminateBox->closeBox();
 			_terminateBox = nullptr;
 		}
-		request(MTPauth_ResetAuthorizations(
+		_api.request(MTPauth_ResetAuthorizations(
 		)).done([=](const MTPBool &result) {
-			request(base::take(_shortPollRequest)).cancel();
+			_api.request(base::take(_shortPollRequest)).cancel();
 			shortPollSessions();
 		}).fail([=](const RPCError &result) {
-			request(base::take(_shortPollRequest)).cancel();
+			_api.request(base::take(_shortPollRequest)).cancel();
 			shortPollSessions();
 		}).send();
 		setLoading(true);
diff --git a/Telegram/SourceFiles/boxes/sessions_box.h b/Telegram/SourceFiles/boxes/sessions_box.h
index b27ec5dd4..b2c7953eb 100644
--- a/Telegram/SourceFiles/boxes/sessions_box.h
+++ b/Telegram/SourceFiles/boxes/sessions_box.h
@@ -22,7 +22,7 @@ namespace Main {
 class Session;
 } // namespace Main
 
-class SessionsBox : public Ui::BoxContent, private MTP::Sender {
+class SessionsBox : public Ui::BoxContent {
 public:
 	SessionsBox(QWidget*, not_null<Main::Session*> session);
 
@@ -60,6 +60,7 @@ private:
 	void terminateAll();
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	bool _loading = false;
 	Full _data;
diff --git a/Telegram/SourceFiles/boxes/sticker_set_box.cpp b/Telegram/SourceFiles/boxes/sticker_set_box.cpp
index 597d71826..b5a496112 100644
--- a/Telegram/SourceFiles/boxes/sticker_set_box.cpp
+++ b/Telegram/SourceFiles/boxes/sticker_set_box.cpp
@@ -99,7 +99,7 @@ private:
 	void showPreview();
 
 	not_null<Window::SessionController*> _controller;
-	MTP::Sender _mtp;
+	MTP::Sender _api;
 	std::vector<Element> _elements;
 	std::unique_ptr<Lottie::MultiPlayer> _lottiePlayer;
 	Stickers::Pack _pack;
@@ -220,6 +220,7 @@ StickerSetBox::Inner::Inner(
 	const MTPInputStickerSet &set)
 : RpWidget(parent)
 , _controller(controller)
+, _api(_controller->session().api().instance())
 , _input(set)
 , _previewTimer([=] { showPreview(); }) {
 	set.match([&](const MTPDinputStickerSetID &data) {
@@ -231,7 +232,7 @@ StickerSetBox::Inner::Inner(
 	}, [&](const MTPDinputStickerSetAnimatedEmoji &) {
 	});
 
-	_mtp.request(MTPmessages_GetStickerSet(
+	_api.request(MTPmessages_GetStickerSet(
 		_input
 	)).done([=](const MTPmessages_StickerSet &result) {
 		gotSet(result);
@@ -700,7 +701,7 @@ void StickerSetBox::Inner::install() {
 	} else if (_installRequest) {
 		return;
 	}
-	_installRequest = _mtp.request(MTPmessages_InstallStickerSet(
+	_installRequest = _api.request(MTPmessages_InstallStickerSet(
 		_input,
 		MTP_bool(false)
 	)).done([=](const MTPmessages_StickerSetInstallResult &result) {
diff --git a/Telegram/SourceFiles/boxes/stickers_box.cpp b/Telegram/SourceFiles/boxes/stickers_box.cpp
index c426a2316..1be373e51 100644
--- a/Telegram/SourceFiles/boxes/stickers_box.cpp
+++ b/Telegram/SourceFiles/boxes/stickers_box.cpp
@@ -661,6 +661,7 @@ StickersBox::Inner::Inner(
 	StickersBox::Section section)
 : RpWidget(parent)
 , _session(session)
+, _api(_session->api().instance())
 , _section(section)
 , _rowHeight(st::contactsPadding.top() + st::contactsPhotoSize + st::contactsPadding.bottom())
 , _shiftingAnimation([=](crl::time now) {
@@ -677,6 +678,7 @@ StickersBox::Inner::Inner(
 StickersBox::Inner::Inner(QWidget *parent, not_null<ChannelData*> megagroup)
 : RpWidget(parent)
 , _session(&megagroup->session())
+, _api(_session->api().instance())
 , _section(StickersBox::Section::Installed)
 , _rowHeight(st::contactsPadding.top() + st::contactsPhotoSize + st::contactsPadding.bottom())
 , _shiftingAnimation([=](crl::time now) {
@@ -1469,11 +1471,13 @@ void StickersBox::Inner::handleMegagroupSetAddressChange() {
 			}
 		}
 	} else if (!_megagroupSetRequestId) {
-		_megagroupSetRequestId = request(MTPmessages_GetStickerSet(MTP_inputStickerSetShortName(MTP_string(text)))).done([this](const MTPmessages_StickerSet &result) {
+		_megagroupSetRequestId = _api.request(MTPmessages_GetStickerSet(
+			MTP_inputStickerSetShortName(MTP_string(text))
+		)).done([=](const MTPmessages_StickerSet &result) {
 			_megagroupSetRequestId = 0;
 			auto set = Stickers::FeedSetFull(result);
 			setMegagroupSelectedSet(MTP_inputStickerSetID(MTP_long(set->id), MTP_long(set->access)));
-		}).fail([this](const RPCError &error) {
+		}).fail([=](const RPCError &error) {
 			_megagroupSetRequestId = 0;
 			setMegagroupSelectedSet(MTP_inputStickerSetEmpty());
 		}).send();
diff --git a/Telegram/SourceFiles/boxes/stickers_box.h b/Telegram/SourceFiles/boxes/stickers_box.h
index d5aba39ed..3cdd90a18 100644
--- a/Telegram/SourceFiles/boxes/stickers_box.h
+++ b/Telegram/SourceFiles/boxes/stickers_box.h
@@ -153,8 +153,7 @@ private:
 // This class is hold in header because it requires Qt preprocessing.
 class StickersBox::Inner
 	: public Ui::RpWidget
-	, private base::Subscriber
-	, private MTP::Sender {
+	, private base::Subscriber {
 	Q_OBJECT
 
 public:
@@ -320,6 +319,7 @@ private:
 	int countMaxNameWidth() const;
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	Section _section;
 
diff --git a/Telegram/SourceFiles/calls/calls_box_controller.cpp b/Telegram/SourceFiles/calls/calls_box_controller.cpp
index ab5189452..7b2000892 100644
--- a/Telegram/SourceFiles/calls/calls_box_controller.cpp
+++ b/Telegram/SourceFiles/calls/calls_box_controller.cpp
@@ -21,6 +21,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_media_types.h"
 #include "data/data_user.h"
+#include "apiwrap.h"
 #include "facades.h"
 #include "app.h"
 
@@ -216,7 +217,8 @@ void BoxController::Row::stopLastActionRipple() {
 }
 
 BoxController::BoxController(not_null<Window::SessionController*> window)
-: _window(window) {
+: _window(window)
+, _api(_window->session().api().instance()) {
 }
 
 Main::Session &BoxController::session() const {
@@ -256,7 +258,7 @@ void BoxController::loadMoreRows() {
 		return;
 	}
 
-	_loadRequestId = request(MTPmessages_Search(
+	_loadRequestId = _api.request(MTPmessages_Search(
 		MTP_flags(0),
 		MTP_inputPeerEmpty(),
 		MTP_string(),
diff --git a/Telegram/SourceFiles/calls/calls_box_controller.h b/Telegram/SourceFiles/calls/calls_box_controller.h
index 9833469f1..d67e22c04 100644
--- a/Telegram/SourceFiles/calls/calls_box_controller.h
+++ b/Telegram/SourceFiles/calls/calls_box_controller.h
@@ -15,10 +15,7 @@ class SessionController;
 
 namespace Calls {
 
-class BoxController
-	: public PeerListController
-	, private base::Subscriber
-	, private MTP::Sender {
+class BoxController : public PeerListController, private base::Subscriber {
 public:
 	explicit BoxController(not_null<Window::SessionController*> window);
 
@@ -44,6 +41,7 @@ private:
 		not_null<HistoryItem*> item) const;
 
 	const not_null<Window::SessionController*> _window;
+	MTP::Sender _api;
 
 	MsgId _offsetId = 0;
 	mtpRequestId _loadRequestId = 0;
diff --git a/Telegram/SourceFiles/calls/calls_call.cpp b/Telegram/SourceFiles/calls/calls_call.cpp
index 7539f1544..bf57bdca4 100644
--- a/Telegram/SourceFiles/calls/calls_call.cpp
+++ b/Telegram/SourceFiles/calls/calls_call.cpp
@@ -130,6 +130,7 @@ Call::Call(
 	Type type)
 : _delegate(delegate)
 , _user(user)
+, _api(_user->session().api().instance())
 , _type(type) {
 	_discardByTimeoutTimer.setCallback([this] { hangup(); });
 
@@ -189,7 +190,7 @@ void Call::startOutgoing() {
 	Expects(_state == State::Requesting);
 	Expects(_gaHash.size() == kSha256Size);
 
-	request(MTPphone_RequestCall(
+	_api.request(MTPphone_RequestCall(
 		MTP_flags(0),
 		_user->inputUser,
 		MTP_int(rand_value<int32>()),
@@ -236,11 +237,13 @@ void Call::startIncoming() {
 	Expects(_type == Type::Incoming);
 	Expects(_state == State::Starting);
 
-	request(MTPphone_ReceivedCall(MTP_inputPhoneCall(MTP_long(_id), MTP_long(_accessHash)))).done([this](const MTPBool &result) {
+	_api.request(MTPphone_ReceivedCall(
+		MTP_inputPhoneCall(MTP_long(_id), MTP_long(_accessHash))
+	)).done([=](const MTPBool &result) {
 		if (_state == State::Starting) {
 			setState(State::WaitingIncoming);
 		}
-	}).fail([this](const RPCError &error) {
+	}).fail([=](const RPCError &error) {
 		handleRequestError(error);
 	}).send();
 }
@@ -267,7 +270,7 @@ void Call::actuallyAnswer() {
 	} else {
 		_answerAfterDhConfigReceived = false;
 	}
-	request(MTPphone_AcceptCall(
+	_api.request(MTPphone_AcceptCall(
 		MTP_inputPhoneCall(MTP_long(_id), MTP_long(_accessHash)),
 		MTP_bytes(_gb),
 		MTP_phoneCallProtocol(
@@ -504,7 +507,7 @@ void Call::confirmAcceptedCall(const MTPDphoneCallAccepted &call) {
 	_keyFingerprint = ComputeFingerprint(_authKey);
 
 	setState(State::ExchangingKeys);
-	request(MTPphone_ConfirmCall(
+	_api.request(MTPphone_ConfirmCall(
 		MTP_inputPhoneCall(MTP_long(_id), MTP_long(_accessHash)),
 		MTP_bytes(_ga),
 		MTP_long(_keyFingerprint),
@@ -840,7 +843,7 @@ void Call::finish(FinishType type, const MTPPhoneCallDiscardReason &reason) {
 	auto duration = getDurationMs() / 1000;
 	auto connectionId = _controller ? _controller->GetPreferredRelayID() : 0;
 	_finishByTimeoutTimer.call(kHangupTimeoutMs, [this, finalState] { setState(finalState); });
-	request(MTPphone_DiscardCall(
+	_api.request(MTPphone_DiscardCall(
 		MTP_flags(0),
 		MTP_inputPhoneCall(
 			MTP_long(_id),
diff --git a/Telegram/SourceFiles/calls/calls_call.h b/Telegram/SourceFiles/calls/calls_call.h
index 2580b4026..98bc6b5a6 100644
--- a/Telegram/SourceFiles/calls/calls_call.h
+++ b/Telegram/SourceFiles/calls/calls_call.h
@@ -31,7 +31,7 @@ struct DhConfig {
 	bytes::vector p;
 };
 
-class Call : public base::has_weak_ptr, private MTP::Sender {
+class Call : public base::has_weak_ptr {
 public:
 	class Delegate {
 	public:
@@ -183,6 +183,7 @@ private:
 
 	not_null<Delegate*> _delegate;
 	not_null<UserData*> _user;
+	MTP::Sender _api;
 	Type _type = Type::Outgoing;
 	State _state = State::Starting;
 	FinishType _finishAfterRequestingCall = FinishType::None;
diff --git a/Telegram/SourceFiles/calls/calls_instance.cpp b/Telegram/SourceFiles/calls/calls_instance.cpp
index 7da4cef5e..6faaff119 100644
--- a/Telegram/SourceFiles/calls/calls_instance.cpp
+++ b/Telegram/SourceFiles/calls/calls_instance.cpp
@@ -32,7 +32,9 @@ constexpr auto kServerConfigUpdateTimeoutMs = 24 * 3600 * crl::time(1000);
 
 } // namespace
 
-Instance::Instance(not_null<Main::Session*> session) : _session(session) {
+Instance::Instance(not_null<Main::Session*> session)
+: _session(session)
+, _api(_session->api().instance()) {
 }
 
 void Instance::startOutgoingCall(not_null<UserData*> user) {
@@ -139,7 +141,7 @@ void Instance::refreshDhConfig() {
 	Expects(_currentCall != nullptr);
 
 	const auto weak = base::make_weak(_currentCall);
-	request(MTPmessages_GetDhConfig(
+	_api.request(MTPmessages_GetDhConfig(
 		MTP_int(_dhConfig.version),
 		MTP_int(MTP::ModExpFirst::kRandomPowerSize)
 	)).done([=](const MTPmessages_DhConfig &result) {
@@ -203,13 +205,14 @@ void Instance::refreshServerConfig() {
 	if (_lastServerConfigUpdateTime && (crl::now() - _lastServerConfigUpdateTime) < kServerConfigUpdateTimeoutMs) {
 		return;
 	}
-	_serverConfigRequestId = request(MTPphone_GetCallConfig()).done([this](const MTPDataJSON &result) {
+	_serverConfigRequestId = _api.request(MTPphone_GetCallConfig(
+	)).done([=](const MTPDataJSON &result) {
 		_serverConfigRequestId = 0;
 		_lastServerConfigUpdateTime = crl::now();
 
 		const auto &json = result.c_dataJSON().vdata().v;
 		UpdateConfig(std::string(json.data(), json.size()));
-	}).fail([this](const RPCError &error) {
+	}).fail([=](const RPCError &error) {
 		_serverConfigRequestId = 0;
 	}).send();
 }
@@ -246,7 +249,7 @@ void Instance::handleCallUpdate(const MTPPhoneCall &call) {
 			LOG(("API Error: Self found in phoneCallRequested."));
 		}
 		if (alreadyInCall() || !user || user->isSelf()) {
-			request(MTPphone_DiscardCall(
+			_api.request(MTPphone_DiscardCall(
 				MTP_flags(0),
 				MTP_inputPhoneCall(phoneCall.vid(), phoneCall.vaccess_hash()),
 				MTP_int(0),
diff --git a/Telegram/SourceFiles/calls/calls_instance.h b/Telegram/SourceFiles/calls/calls_instance.h
index f5d30fa9b..d8987f458 100644
--- a/Telegram/SourceFiles/calls/calls_instance.h
+++ b/Telegram/SourceFiles/calls/calls_instance.h
@@ -25,8 +25,7 @@ namespace Calls {
 class Panel;
 
 class Instance
-	: private MTP::Sender
-	, private Call::Delegate
+	: private Call::Delegate
 	, private base::Subscriber
 	, public base::has_weak_ptr {
 public:
@@ -74,6 +73,7 @@ private:
 	void handleCallUpdate(const MTPPhoneCall &call);
 
 	const not_null<Main::Session*> _session;
+	MTP::Sender _api;
 
 	DhConfig _dhConfig;
 
diff --git a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
index 274f12f61..a99c0ecbe 100644
--- a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
@@ -22,6 +22,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/localstorage.h"
 #include "lang/lang_keys.h"
 #include "mainwindow.h"
+#include "apiwrap.h"
 #include "window/window_session_controller.h"
 #include "history/view/history_view_cursor_state.h"
 #include "facades.h"
@@ -130,6 +131,7 @@ GifsListWidget::GifsListWidget(
 	QWidget *parent,
 	not_null<Window::SessionController*> controller)
 : Inner(parent, controller)
+, _api(controller->session().api().instance())
 , _section(Section::Gifs)
 , _updateInlineItems([=] { updateInlineItems(); })
 , _previewTimer([=] { showPreview(); }) {
@@ -217,7 +219,7 @@ GifsListWidget::~GifsListWidget() {
 void GifsListWidget::cancelGifsSearch() {
 	_footer->setLoading(false);
 	if (_inlineRequestId) {
-		request(_inlineRequestId).cancel();
+		_api.request(_inlineRequestId).cancel();
 		_inlineRequestId = 0;
 	}
 	_inlineRequestTimer.stop();
@@ -840,7 +842,7 @@ void GifsListWidget::searchForGifs(const QString &query) {
 	if (_inlineQuery != query) {
 		_footer->setLoading(false);
 		if (_inlineRequestId) {
-			request(_inlineRequestId).cancel();
+			_api.request(_inlineRequestId).cancel();
 			_inlineRequestId = 0;
 		}
 		if (_inlineCache.find(query) != _inlineCache.cend()) {
@@ -855,7 +857,7 @@ void GifsListWidget::searchForGifs(const QString &query) {
 
 	if (!_searchBot && !_searchBotRequestId) {
 		auto username = str_const_toString(kSearchBotUsername);
-		_searchBotRequestId = request(MTPcontacts_ResolveUsername(
+		_searchBotRequestId = _api.request(MTPcontacts_ResolveUsername(
 			MTP_string(username)
 		)).done([=](const MTPcontacts_ResolvedPeer &result) {
 			Expects(result.type() == mtpc_contacts_resolvedPeer);
@@ -905,7 +907,7 @@ void GifsListWidget::sendInlineRequest() {
 	}
 
 	_footer->setLoading(true);
-	_inlineRequestId = request(MTPmessages_GetInlineBotResults(
+	_inlineRequestId = _api.request(MTPmessages_GetInlineBotResults(
 		MTP_flags(0),
 		_searchBot->inputUser,
 		_inlineQueryPeer->input,
diff --git a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.h b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.h
index 1859459c0..f1ae5e73f 100644
--- a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.h
+++ b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.h
@@ -34,8 +34,7 @@ namespace ChatHelpers {
 class GifsListWidget
 	: public TabbedSelector::Inner
 	, public InlineBots::Layout::Context
-	, private base::Subscriber
-	, private MTP::Sender {
+	, private base::Subscriber {
 public:
 	using InlineChosen = TabbedSelector::InlineChosen;
 
@@ -119,6 +118,8 @@ private:
 	void updateInlineItems();
 	void showPreview();
 
+	MTP::Sender _api;
+
 	Section _section = Section::Gifs;
 	crl::time _lastScrolled = 0;
 	base::Timer _updateInlineItems;
diff --git a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
index d53b516a0..3a5afa29e 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
@@ -828,6 +828,7 @@ StickersListWidget::StickersListWidget(
 	QWidget *parent,
 	not_null<Window::SessionController*> controller)
 : Inner(parent, controller)
+, _api(controller->session().api().instance())
 , _section(Section::Stickers)
 , _megagroupSetAbout(st::columnMinimalWidthThird - st::emojiScroll.width - st::emojiPanHeaderLeft)
 , _addText(tr::lng_stickers_featured_add(tr::now).toUpper())
@@ -1069,7 +1070,7 @@ void StickersListWidget::sendSearchRequest() {
 
 	_footer->setLoading(true);
 	const auto hash = int32(0);
-	_searchRequestId = request(MTPmessages_SearchStickerSets(
+	_searchRequestId = _api.request(MTPmessages_SearchStickerSets(
 		MTP_flags(0),
 		MTP_string(_searchQuery),
 		MTP_int(hash)
@@ -1092,7 +1093,7 @@ void StickersListWidget::searchForSets(const QString &query) {
 	if (_searchQuery != cleaned) {
 		_footer->setLoading(false);
 		if (const auto requestId = base::take(_searchRequestId)) {
-			request(requestId).cancel();
+			_api.request(requestId).cancel();
 		}
 		if (_searchCache.find(cleaned) != _searchCache.cend()) {
 			_searchRequestTimer.cancel();
@@ -1108,7 +1109,7 @@ void StickersListWidget::searchForSets(const QString &query) {
 void StickersListWidget::cancelSetsSearch() {
 	_footer->setLoading(false);
 	if (const auto requestId = base::take(_searchRequestId)) {
-		request(requestId).cancel();
+		_api.request(requestId).cancel();
 	}
 	_searchRequestTimer.cancel();
 	_searchQuery = _searchNextQuery = QString();
@@ -2468,7 +2469,7 @@ void StickersListWidget::refreshMegagroupStickers(GroupStickersPlace place) {
 		return;
 	}
 	_megagroupSetIdRequested = set.vid().v;
-	request(MTPmessages_GetStickerSet(
+	_api.request(MTPmessages_GetStickerSet(
 		_megagroupSet->mgInfo->stickerSet
 	)).done([=](const MTPmessages_StickerSet &result) {
 		if (const auto set = Stickers::FeedSetFull(result)) {
@@ -2810,7 +2811,7 @@ void StickersListWidget::installSet(uint64 setId) {
 		const auto input = Stickers::inputSetId(*it);
 		if ((it->flags & MTPDstickerSet_ClientFlag::f_not_loaded)
 			|| it->stickers.empty()) {
-			request(MTPmessages_GetStickerSet(
+			_api.request(MTPmessages_GetStickerSet(
 				input
 			)).done([=](const MTPmessages_StickerSet &result) {
 				Stickers::FeedSetFull(result);
@@ -2825,7 +2826,7 @@ void StickersListWidget::installSet(uint64 setId) {
 void StickersListWidget::sendInstallRequest(
 		uint64 setId,
 		const MTPInputStickerSet &input) {
-	request(MTPmessages_InstallStickerSet(
+	_api.request(MTPmessages_InstallStickerSet(
 		input,
 		MTP_bool(false)
 	)).done([=](const MTPmessages_StickerSetInstallResult &result) {
@@ -2876,9 +2877,9 @@ void StickersListWidget::removeSet(uint64 setId) {
 			auto it = sets.find(_removingSetId);
 			if (it != sets.cend()) {
 				if (it->id && it->access) {
-					request(MTPmessages_UninstallStickerSet(MTP_inputStickerSetID(MTP_long(it->id), MTP_long(it->access)))).send();
+					_api.request(MTPmessages_UninstallStickerSet(MTP_inputStickerSetID(MTP_long(it->id), MTP_long(it->access)))).send();
 				} else if (!it->shortName.isEmpty()) {
-					request(MTPmessages_UninstallStickerSet(MTP_inputStickerSetShortName(MTP_string(it->shortName)))).send();
+					_api.request(MTPmessages_UninstallStickerSet(MTP_inputStickerSetShortName(MTP_string(it->shortName)))).send();
 				}
 				auto writeRecent = false;
 				auto &recent = Stickers::GetRecentPack();
diff --git a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.h b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.h
index 53c11c794..b0e17bea7 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.h
+++ b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.h
@@ -38,8 +38,7 @@ struct StickerIcon;
 
 class StickersListWidget
 	: public TabbedSelector::Inner
-	, private base::Subscriber
-	, private MTP::Sender {
+	, private base::Subscriber {
 public:
 	StickersListWidget(
 		QWidget *parent,
@@ -300,6 +299,7 @@ private:
 
 	void showPreview();
 
+	MTP::Sender _api;
 	ChannelData *_megagroupSet = nullptr;
 	uint64 _megagroupSetIdRequested = 0;
 	std::vector<Set> _mySets;
diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index 916af7b22..048a6794e 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -93,6 +93,7 @@ Application::Application(not_null<Launcher*> launcher)
 , _dcOptions(std::make_unique<MTP::DcOptions>())
 , _account(std::make_unique<Main::Account>(cDataFile()))
 , _langpack(std::make_unique<Lang::Instance>())
+, _langCloudManager(std::make_unique<Lang::CloudManager>(langpack()))
 , _emojiKeywords(std::make_unique<ChatHelpers::EmojiKeywords>())
 , _audio(std::make_unique<Media::Audio::Instance>())
 , _logo(Window::LoadLogo())
@@ -114,9 +115,6 @@ Application::Application(not_null<Launcher*> launcher)
 	) | rpl::filter([=](MTP::Instance *instance) {
 		return instance != nullptr;
 	}) | rpl::start_with_next([=](not_null<MTP::Instance*> mtp) {
-		_langCloudManager = std::make_unique<Lang::CloudManager>(
-			langpack(),
-			mtp);
 		if (!UpdaterDisabled()) {
 			UpdateChecker().setMtproto(mtp.get());
 		}
@@ -134,11 +132,6 @@ Application::~Application() {
 	// Some MTP requests can be cancelled from data clearing.
 	unlockTerms();
 	activeAccount().destroySession();
-
-	// The langpack manager should be destroyed before MTProto instance,
-	// because it is MTP::Sender and it may have pending requests.
-	_langCloudManager.reset();
-
 	activeAccount().clearMtp();
 
 	Shortcuts::Finish();
diff --git a/Telegram/SourceFiles/core/application.h b/Telegram/SourceFiles/core/application.h
index 1f68e48a0..6854aaa32 100644
--- a/Telegram/SourceFiles/core/application.h
+++ b/Telegram/SourceFiles/core/application.h
@@ -266,7 +266,7 @@ private:
 	std::unique_ptr<Window::Controller> _window;
 	std::unique_ptr<Media::View::OverlayWidget> _mediaView;
 	const std::unique_ptr<Lang::Instance> _langpack;
-	std::unique_ptr<Lang::CloudManager> _langCloudManager;
+	const std::unique_ptr<Lang::CloudManager> _langCloudManager;
 	const std::unique_ptr<ChatHelpers::EmojiKeywords> _emojiKeywords;
 	std::unique_ptr<Lang::Translator> _translator;
 	base::Observable<void> _passcodedChanged;
diff --git a/Telegram/SourceFiles/data/data_search_controller.cpp b/Telegram/SourceFiles/data/data_search_controller.cpp
index 01dcf7f86..243654287 100644
--- a/Telegram/SourceFiles/data/data_search_controller.cpp
+++ b/Telegram/SourceFiles/data/data_search_controller.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "history/history.h"
 #include "history/history_item.h"
+#include "apiwrap.h"
 
 namespace Api {
 namespace {
@@ -191,6 +192,10 @@ SearchController::CacheEntry::CacheEntry(const Query &query)
 	: std::nullopt) {
 }
 
+SearchController::SearchController(not_null<Main::Session*> session)
+: _api(session->api().instance()) {
+}
+
 bool SearchController::hasInCache(const Query &query) const {
 	return query.query.isEmpty() || _cache.contains(query);
 }
@@ -361,7 +366,7 @@ void SearchController::requestMore(
 	if (!prepared) {
 		return;
 	}
-	auto requestId = request(
+	auto requestId = _api.request(
 		std::move(*prepared)
 	).done([=](const MTPmessages_Messages &result) {
 		listData->requests.remove(key);
@@ -377,11 +382,13 @@ void SearchController::requestMore(
 			parsed.fullCount);
 	}).send();
 	listData->requests.emplace(key, [=] {
-		request(requestId).cancel();
+		_api.request(requestId).cancel();
 	});
 }
 
-DelayedSearchController::DelayedSearchController() {
+DelayedSearchController::DelayedSearchController(
+	not_null<Main::Session*> session)
+: _controller(session) {
 	_timer.setCallback([this] { setQueryFast(_nextQuery); });
 }
 
diff --git a/Telegram/SourceFiles/data/data_search_controller.h b/Telegram/SourceFiles/data/data_search_controller.h
index c166d59f3..fcc2b8853 100644
--- a/Telegram/SourceFiles/data/data_search_controller.h
+++ b/Telegram/SourceFiles/data/data_search_controller.h
@@ -14,6 +14,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/value_ordering.h"
 #include "base/timer.h"
 
+namespace Main {
+class Session;
+} // namespace Main
+
 namespace Data {
 enum class LoadDirection : char;
 } // namespace Data
@@ -40,7 +44,7 @@ SearchResult ParseSearchResult(
 	Data::LoadDirection direction,
 	const MTPmessages_Messages &data);
 
-class SearchController : private MTP::Sender {
+class SearchController final {
 public:
 	using IdsList = Storage::SparseIdsList;
 	struct Query {
@@ -67,6 +71,7 @@ public:
 		std::optional<IdsList> migratedList;
 	};
 
+	explicit SearchController(not_null<Main::Session*> session);
 	void setQuery(const Query &query);
 	bool hasInCache(const Query &query) const;
 
@@ -124,6 +129,7 @@ private:
 		const Query &query,
 		Data *listData);
 
+	MTP::Sender _api;
 	Cache _cache;
 	Cache::iterator _current = _cache.end();
 
@@ -131,7 +137,7 @@ private:
 
 class DelayedSearchController {
 public:
-	DelayedSearchController();
+	explicit DelayedSearchController(not_null<Main::Session*> session);
 
 	using Query = SearchController::Query;
 	using SavedState = SearchController::SavedState;
diff --git a/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.cpp b/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.cpp
index 555364637..31758e82d 100644
--- a/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.cpp
+++ b/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.cpp
@@ -226,6 +226,7 @@ InnerWidget::InnerWidget(
 , _controller(controller)
 , _channel(channel)
 , _history(channel->owner().history(channel))
+, _api(_channel->session().api().instance())
 , _scrollDateCheck([=] { scrollDateCheck(); })
 , _emptyText(
 		st::historyAdminLogEmptyWidth
@@ -407,7 +408,7 @@ void InnerWidget::applySearch(const QString &query) {
 
 void InnerWidget::requestAdmins() {
 	auto participantsHash = 0;
-	request(MTPchannels_GetParticipants(
+	_api.request(MTPchannels_GetParticipants(
 		_channel->inputChannel,
 		MTP_channelParticipantsAdmins(),
 		MTP_int(0),
@@ -463,8 +464,8 @@ void InnerWidget::showFilter(Fn<void(FilterValue &&filter)> callback) {
 }
 
 void InnerWidget::clearAndRequestLog() {
-	request(base::take(_preloadUpRequestId)).cancel();
-	request(base::take(_preloadDownRequestId)).cancel();
+	_api.request(base::take(_preloadUpRequestId)).cancel();
+	_api.request(base::take(_preloadDownRequestId)).cancel();
 	_filterChanged = true;
 	_upLoaded = false;
 	_downLoaded = true;
@@ -635,7 +636,7 @@ void InnerWidget::preloadMore(Direction direction) {
 	auto maxId = (direction == Direction::Up) ? _minId : 0;
 	auto minId = (direction == Direction::Up) ? 0 : _maxId;
 	auto perPage = _items.empty() ? kEventsFirstPage : kEventsPerPage;
-	requestId = request(MTPchannels_GetAdminLog(
+	requestId = _api.request(MTPchannels_GetAdminLog(
 		MTP_flags(flags),
 		_channel->inputChannel,
 		MTP_string(_searchQuery),
@@ -1217,7 +1218,7 @@ void InnerWidget::suggestRestrictUser(not_null<UserData*> user) {
 		if (base::contains(_admins, user)) {
 			editRestrictions(true, MTP_chatBannedRights(MTP_flags(0), MTP_int(0)));
 		} else {
-			request(MTPchannels_GetParticipant(
+			_api.request(MTPchannels_GetParticipant(
 				_channel->inputChannel,
 				user->inputUser
 			)).done([=](const MTPchannels_ChannelParticipant &result) {
diff --git a/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.h b/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.h
index f20c58382..c9405ea05 100644
--- a/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.h
+++ b/Telegram/SourceFiles/history/admin_log/history_admin_log_inner.h
@@ -44,7 +44,6 @@ class InnerWidget final
 	: public Ui::RpWidget
 	, public Ui::AbstractTooltipShower
 	, public HistoryView::ElementDelegate
-	, private MTP::Sender
 	, private base::Subscriber {
 public:
 	InnerWidget(
@@ -216,9 +215,11 @@ private:
 	template <typename Method>
 	void enumerateDates(Method method);
 
-	not_null<Window::SessionController*> _controller;
-	not_null<ChannelData*> _channel;
-	not_null<History*> _history;
+	const not_null<Window::SessionController*> _controller;
+	const not_null<ChannelData*> _channel;
+	const not_null<History*> _history;
+	MTP::Sender _api;
+
 	std::vector<OwnedItem> _items;
 	std::set<uint64> _eventIds;
 	std::map<not_null<const HistoryItem*>, not_null<Element*>> _itemsByData;
diff --git a/Telegram/SourceFiles/info/common_groups/info_common_groups_inner_widget.cpp b/Telegram/SourceFiles/info/common_groups/info_common_groups_inner_widget.cpp
index 47427556a..065ef7857 100644
--- a/Telegram/SourceFiles/info/common_groups/info_common_groups_inner_widget.cpp
+++ b/Telegram/SourceFiles/info/common_groups/info_common_groups_inner_widget.cpp
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "info/info_controller.h"
 #include "lang/lang_keys.h"
 #include "mtproto/sender.h"
+#include "main/main_session.h"
 #include "window/window_session_controller.h"
 #include "ui/widgets/scroll_area.h"
 #include "ui/search_field_controller.h"
@@ -27,10 +28,7 @@ namespace {
 constexpr auto kCommonGroupsPerPage = 40;
 constexpr auto kCommonGroupsSearchAfter = 20;
 
-class ListController
-	: public PeerListController
-	, private base::Subscriber
-	, private MTP::Sender {
+class ListController : public PeerListController , private base::Subscriber {
 public:
 	ListController(
 		not_null<Controller*> controller,
@@ -58,6 +56,7 @@ private:
 		bool wasLoading = false;
 	};
 	const not_null<Controller*> _controller;
+	MTP::Sender _api;
 	not_null<UserData*> _user;
 	mtpRequestId _preloadRequestId = 0;
 	bool _allLoaded = false;
@@ -70,6 +69,7 @@ ListController::ListController(
 	not_null<UserData*> user)
 : PeerListController()
 , _controller(controller)
+, _api(_controller->session().api().instance())
 , _user(user) {
 	_controller->setSearchEnabledByContent(false);
 }
@@ -95,7 +95,7 @@ void ListController::loadMoreRows() {
 	if (_preloadRequestId || _allLoaded) {
 		return;
 	}
-	_preloadRequestId = request(MTPmessages_GetCommonChats(
+	_preloadRequestId = _api.request(MTPmessages_GetCommonChats(
 		_user->inputUser,
 		MTP_int(_preloadGroupId),
 		MTP_int(kCommonGroupsPerPage)
@@ -143,7 +143,7 @@ void ListController::restoreState(
 		: nullptr;
 	if (auto my = dynamic_cast<SavedState*>(typeErasedState)) {
 		if (auto requestId = base::take(_preloadRequestId)) {
-			request(requestId).cancel();
+			_api.request(requestId).cancel();
 		}
 		_allLoaded = my->allLoaded;
 		_preloadGroupId = my->preloadGroupId;
diff --git a/Telegram/SourceFiles/info/info_controller.cpp b/Telegram/SourceFiles/info/info_controller.cpp
index 68c328428..41f6951f6 100644
--- a/Telegram/SourceFiles/info/info_controller.cpp
+++ b/Telegram/SourceFiles/info/info_controller.cpp
@@ -196,7 +196,7 @@ void Controller::updateSearchControllers(
 	auto searchQuery = memento->searchFieldQuery();
 	if (isMedia) {
 		_searchController
-			= std::make_unique<Api::DelayedSearchController>();
+			= std::make_unique<Api::DelayedSearchController>(&session());
 		auto mediaMemento = dynamic_cast<Media::Memento*>(memento.get());
 		Assert(mediaMemento != nullptr);
 		_searchController->restoreState(
diff --git a/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp b/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
index 87d9e7da6..03fdf601c 100644
--- a/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
+++ b/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
@@ -754,6 +754,7 @@ Widget::Widget(
 	not_null<Window::SessionController*> controller)
 : RpWidget(parent)
 , _controller(controller)
+, _api(_controller->session().api().instance())
 , _contentMaxHeight(st::emojiPanMaxHeight)
 , _contentHeight(_contentMaxHeight)
 , _scroll(this, st::inlineBotsScroll) {
@@ -1133,9 +1134,16 @@ void Widget::onInlineRequest() {
 		}
 	}
 	Notify::inlineBotRequesting(true);
-	_inlineRequestId = request(MTPmessages_GetInlineBotResults(MTP_flags(0), _inlineBot->inputUser, _inlineQueryPeer->input, MTPInputGeoPoint(), MTP_string(_inlineQuery), MTP_string(nextOffset))).done([this](const MTPmessages_BotResults &result, mtpRequestId requestId) {
+	_inlineRequestId = _api.request(MTPmessages_GetInlineBotResults(
+		MTP_flags(0),
+		_inlineBot->inputUser,
+		_inlineQueryPeer->input,
+		MTPInputGeoPoint(),
+		MTP_string(_inlineQuery),
+		MTP_string(nextOffset)
+	)).done([=](const MTPmessages_BotResults &result) {
 		inlineResultsDone(result);
-	}).fail([this](const RPCError &error) {
+	}).fail([=](const RPCError &error) {
 		// show error?
 		Notify::inlineBotRequesting(false);
 		_inlineRequestId = 0;
diff --git a/Telegram/SourceFiles/inline_bots/inline_results_widget.h b/Telegram/SourceFiles/inline_bots/inline_results_widget.h
index 2c2281e89..d17b9da4c 100644
--- a/Telegram/SourceFiles/inline_bots/inline_results_widget.h
+++ b/Telegram/SourceFiles/inline_bots/inline_results_widget.h
@@ -173,7 +173,7 @@ private:
 
 } // namespace internal
 
-class Widget : public Ui::RpWidget, private MTP::Sender {
+class Widget : public Ui::RpWidget {
 	Q_OBJECT
 
 public:
@@ -246,6 +246,7 @@ private:
 	void inlineResultsDone(const MTPmessages_BotResults &result);
 
 	not_null<Window::SessionController*> _controller;
+	MTP::Sender _api;
 
 	int _contentMaxHeight = 0;
 	int _contentHeight = 0;
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index 2eb46ef52..92203e316 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -170,12 +170,12 @@ QrWidget::QrWidget(
 	not_null<Main::Account*> account,
 	not_null<Data*> data)
 : Step(parent, account, data)
+, _api(account->mtp())
 , _refreshTimer([=] { refreshCode(); }) {
 	setTitleText(rpl::single(QString()));
 	setDescriptionText(rpl::single(QString()));
 	setErrorCentered(true);
 
-	account->destroyStaleAuthorizationKeys();
 	account->mtpUpdates(
 	) | rpl::start_with_next([=](const MTPUpdates &updates) {
 		checkForTokenUpdate(updates);
diff --git a/Telegram/SourceFiles/intro/intro_qr.h b/Telegram/SourceFiles/intro/intro_qr.h
index 0a97d263d..6bad082fb 100644
--- a/Telegram/SourceFiles/intro/intro_qr.h
+++ b/Telegram/SourceFiles/intro/intro_qr.h
@@ -52,9 +52,9 @@ private:
 	void showToken(const QByteArray &token);
 	void done(const MTPauth_Authorization &authorization);
 
+	MTP::Sender _api;
 	rpl::event_stream<QByteArray> _qrCodes;
 	base::Timer _refreshTimer;
-	MTP::Sender _api;
 	mtpRequestId _requestId = 0;
 	bool _forceRefresh = false;
 
diff --git a/Telegram/SourceFiles/intro/intro_step.h b/Telegram/SourceFiles/intro/intro_step.h
index 67e2ad225..c53826622 100644
--- a/Telegram/SourceFiles/intro/intro_step.h
+++ b/Telegram/SourceFiles/intro/intro_step.h
@@ -177,7 +177,6 @@ private:
 	object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _description;
 
 	bool _errorCentered = false;
-	bool _errorBelowLink = false;
 	rpl::variable<QString> _errorText;
 	object_ptr<Ui::FadeWrap<Ui::FlatLabel>> _error = { nullptr };
 
diff --git a/Telegram/SourceFiles/intro/introphone.cpp b/Telegram/SourceFiles/intro/introphone.cpp
index e6bee5332..fe070bf52 100644
--- a/Telegram/SourceFiles/intro/introphone.cpp
+++ b/Telegram/SourceFiles/intro/introphone.cpp
@@ -60,8 +60,6 @@ PhoneWidget::PhoneWidget(
 		_country->onChooseCountry(qsl("US"));
 	}
 	_changed = false;
-
-	account->destroyStaleAuthorizationKeys();
 }
 
 void PhoneWidget::resizeEvent(QResizeEvent *e) {
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.cpp b/Telegram/SourceFiles/intro/intropwdcheck.cpp
index 0e5bad618..d56320910 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.cpp
+++ b/Telegram/SourceFiles/intro/intropwdcheck.cpp
@@ -16,6 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/input_fields.h"
 #include "ui/widgets/labels.h"
+#include "main/main_account.h"
 #include "base/openssl_help.h"
 #include "styles/style_intro.h"
 #include "styles/style_boxes.h"
@@ -28,6 +29,7 @@ PwdCheckWidget::PwdCheckWidget(
 	not_null<Main::Account*> account,
 	not_null<Data*> data)
 : Step(parent, account, data)
+, _api(account->mtp())
 , _request(getData()->pwdRequest)
 , _hasRecovery(getData()->hasRecovery)
 , _notEmptyPassport(getData()->pwdNotEmptyPassport)
@@ -115,7 +117,7 @@ void PwdCheckWidget::activate() {
 }
 
 void PwdCheckWidget::cancelled() {
-	request(base::take(_sentRequest)).cancel();
+	_api.request(base::take(_sentRequest)).cancel();
 }
 
 void PwdCheckWidget::stopCheck() {
@@ -127,7 +129,7 @@ void PwdCheckWidget::onCheckRequest() {
 	if (status < 0) {
 		auto leftms = -status;
 		if (leftms >= 1000) {
-			request(base::take(_sentRequest)).cancel();
+			_api.request(base::take(_sentRequest)).cancel();
 		}
 	}
 	if (!_sentRequest && status == MTP::RequestSent) {
@@ -202,8 +204,8 @@ void PwdCheckWidget::checkPasswordHash() {
 }
 
 void PwdCheckWidget::requestPasswordData() {
-	request(base::take(_sentRequest)).cancel();
-	_sentRequest = request(
+	_api.request(base::take(_sentRequest)).cancel();
+	_sentRequest = _api.request(
 		MTPaccount_GetPassword()
 	).done([=](const MTPaccount_Password &result) {
 		_sentRequest = 0;
@@ -225,7 +227,7 @@ void PwdCheckWidget::passwordChecked() {
 		return serverError();
 	}
 	_request.id = 0;
-	_sentRequest = request(
+	_sentRequest = _api.request(
 		MTPauth_CheckPassword(check.result)
 	).done([=](const MTPauth_Authorization &result) {
 		pwdSubmitDone(false, result);
@@ -289,7 +291,7 @@ void PwdCheckWidget::recoverStartFail(const RPCError &error) {
 void PwdCheckWidget::onToRecover() {
 	if (_hasRecovery) {
 		if (_sentRequest) {
-			request(base::take(_sentRequest)).cancel();
+			_api.request(base::take(_sentRequest)).cancel();
 		}
 		hideError();
 		_toRecover->hide();
@@ -301,7 +303,7 @@ void PwdCheckWidget::onToRecover() {
 		_codeField->setFocus();
 		updateDescriptionText();
 		if (_emailPattern.isEmpty()) {
-			request(
+			_api.request(
 				MTPauth_RequestPasswordRecovery()
 			).done([=](const MTPauth_PasswordRecovery &result) {
 				recoverStarted(result);
@@ -320,7 +322,7 @@ void PwdCheckWidget::onToPassword() {
 
 void PwdCheckWidget::showReset() {
 	if (_sentRequest) {
-		request(base::take(_sentRequest)).cancel();
+		_api.request(base::take(_sentRequest)).cancel();
 	}
 	_toRecover->show();
 	_toPassword->hide();
@@ -355,7 +357,7 @@ void PwdCheckWidget::submit() {
 			return;
 		}
 		const auto send = crl::guard(this, [=] {
-			_sentRequest = request(
+			_sentRequest = _api.request(
 				MTPauth_RecoverPassword(MTP_string(code))
 			).done([=](const MTPauth_Authorization &result) {
 				pwdSubmitDone(true, result);
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.h b/Telegram/SourceFiles/intro/intropwdcheck.h
index 02e392eae..98263b410 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.h
+++ b/Telegram/SourceFiles/intro/intropwdcheck.h
@@ -21,7 +21,7 @@ class LinkButton;
 namespace Intro {
 namespace details {
 
-class PwdCheckWidget : public Step, private MTP::Sender {
+class PwdCheckWidget : public Step {
 	Q_OBJECT
 
 public:
@@ -67,6 +67,7 @@ private:
 	void passwordChecked();
 	void serverError();
 
+	MTP::Sender _api;
 	Core::CloudPasswordCheckRequest _request;
 	crl::time _lastSrpIdInvalidTime = 0;
 	bytes::vector _passwordHash;
diff --git a/Telegram/SourceFiles/intro/introstart.cpp b/Telegram/SourceFiles/intro/introstart.cpp
index e5aab0612..b8b3cfc57 100644
--- a/Telegram/SourceFiles/intro/introstart.cpp
+++ b/Telegram/SourceFiles/intro/introstart.cpp
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "intro/intro_qr.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
+#include "main/main_account.h"
 
 namespace Intro {
 namespace details {
@@ -27,6 +28,7 @@ StartWidget::StartWidget(
 }
 
 void StartWidget::submit() {
+	account().destroyStaleAuthorizationKeys();
 	goNext<QrWidget>();
 }
 
diff --git a/Telegram/SourceFiles/intro/introwidget.cpp b/Telegram/SourceFiles/intro/introwidget.cpp
index 493c8913a..f6ed2d7e3 100644
--- a/Telegram/SourceFiles/intro/introwidget.cpp
+++ b/Telegram/SourceFiles/intro/introwidget.cpp
@@ -50,30 +50,42 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 		st::defaultBoxButton))
 , _next(
 	this,
-	object_ptr<Ui::RoundButton>(
+	object_ptr<Ui::RoundButton>(this, nullptr, st::introNextButton))
+, _connecting(std::make_unique<Window::ConnectionState>(
 		this,
-		nullptr,
-		st::introNextButton)) {
+		rpl::single(true))) {
+	appendStep(new StartWidget(this, _account, getData()));
+	fixOrder();
+
 	getData()->country = Platform::SystemCountry();
 
+	_account->mtpValue(
+	) | rpl::start_with_next([=](MTP::Instance *instance) {
+		if (instance) {
+			_api.emplace(instance);
+			createLanguageLink();
+		} else {
+			_api.reset();
+		}
+	}, lifetime());
+	subscribe(Lang::CurrentCloudManager().firstLanguageSuggestion(), [=] {
+		createLanguageLink();
+	});
+
 	_back->entity()->setClickedCallback([=] {
 		historyMove(Direction::Back);
 	});
 	_back->hide(anim::type::instant);
 
-	_next->entity()->setClickedCallback([this] { getStep()->submit(); });
+	_next->entity()->setClickedCallback([=] { getStep()->submit(); });
 
 	_settings->entity()->setClickedCallback([] { App::wnd()->showSettings(); });
 
 	getNearestDC();
-	setupConnectingWidget();
-
-	appendStep(new StartWidget(this, _account, getData()));
-	fixOrder();
-
-	subscribe(Lang::CurrentCloudManager().firstLanguageSuggestion(), [this] { createLanguageLink(); });
-	createLanguageLink();
-	if (_changeLanguage) _changeLanguage->finishAnimating();
+	
+	if (_changeLanguage) {
+		_changeLanguage->finishAnimating();
+	}
 
 	subscribe(Lang::Current().updated(), [this] { refreshLang(); });
 
@@ -98,12 +110,6 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 	}
 }
 
-void Widget::setupConnectingWidget() {
-	_connecting = std::make_unique<Window::ConnectionState>(
-		this,
-		rpl::single(true));
-}
-
 void Widget::refreshLang() {
 	_changeLanguage.destroy();
 	createLanguageLink();
@@ -111,9 +117,13 @@ void Widget::refreshLang() {
 }
 
 void Widget::createLanguageLink() {
-	if (_changeLanguage) return;
+	if (_changeLanguage) {
+		return;
+	}
 
-	auto createLink = [this](const QString &text, const QString &languageId) {
+	const auto createLink = [=](
+			const QString &text,
+			const QString &languageId) {
 		_changeLanguage.create(
 			this,
 			object_ptr<Ui::LinkButton>(this, text));
@@ -134,8 +144,8 @@ void Widget::createLanguageLink() {
 		createLink(
 			Lang::GetOriginalValue(tr::lng_switch_to_this.base),
 			defaultId);
-	} else if (!suggested.isEmpty() && suggested != currentId) {
-		request(MTPlangpack_GetStrings(
+	} else if (!suggested.isEmpty() && suggested != currentId && _api) {
+		_api->request(MTPlangpack_GetStrings(
 			MTP_string(Lang::CloudLangPackName()),
 			MTP_string(suggested),
 			MTP_vector<MTPstring>(1, MTP_string("lng_switch_to_this"))
@@ -339,18 +349,24 @@ void Widget::acceptTerms(Fn<void()> callback) {
 }
 
 void Widget::resetAccount() {
-	if (_resetRequest) return;
+	if (_resetRequest || !_api) {
+		return;
+	}
 
 	Ui::show(Box<ConfirmBox>(tr::lng_signin_sure_reset(tr::now), tr::lng_signin_reset(tr::now), st::attentionBoxButton, crl::guard(this, [this] {
-		if (_resetRequest) return;
-		_resetRequest = request(MTPaccount_DeleteAccount(MTP_string("Forgot password"))).done([this](const MTPBool &result) {
+		if (_resetRequest) {
+			return;
+		}
+		_resetRequest = _api->request(MTPaccount_DeleteAccount(
+			MTP_string("Forgot password")
+		)).done([=](const MTPBool &result) {
 			_resetRequest = 0;
 
 			Ui::hideLayer();
 			moveToStep(
 				new SignupWidget(this, _account, getData()),
 				Direction::Replace);
-		}).fail([this](const RPCError &error) {
+		}).fail([=](const RPCError &error) {
 			_resetRequest = 0;
 
 			const auto &type = error.type();
@@ -410,8 +426,12 @@ void Widget::resetAccount() {
 }
 
 void Widget::getNearestDC() {
-	request(MTPhelp_GetNearestDc()).done([this](const MTPNearestDc &result) {
-		auto &nearest = result.c_nearestDc();
+	if (!_api) {
+		return;
+	}
+	_api->request(MTPhelp_GetNearestDc(
+	)).done([=](const MTPNearestDc &result) {
+		const auto &nearest = result.c_nearestDc();
 		DEBUG_LOG(("Got nearest dc, country: %1, nearest: %2, this: %3"
 			).arg(qs(nearest.vcountry())
 			).arg(nearest.vnearest_dc().v
diff --git a/Telegram/SourceFiles/intro/introwidget.h b/Telegram/SourceFiles/intro/introwidget.h
index e9a84f541..84c53c4d1 100644
--- a/Telegram/SourceFiles/intro/introwidget.h
+++ b/Telegram/SourceFiles/intro/introwidget.h
@@ -72,10 +72,7 @@ class Step;
 
 } // namespace details
 
-class Widget
-	: public Ui::RpWidget
-	, private MTP::Sender
-	, private base::Subscriber {
+class Widget : public Ui::RpWidget, private base::Subscriber {
 public:
 	Widget(QWidget *parent, not_null<Main::Account*> account);
 
@@ -91,7 +88,6 @@ protected:
 	void keyPressEvent(QKeyEvent *e) override;
 
 private:
-	void setupConnectingWidget();
 	void refreshLang();
 	void animationCallback();
 	void createLanguageLink();
@@ -127,7 +123,8 @@ private:
 	void getNearestDC();
 	void showTerms(Fn<void()> callback);
 
-	not_null<Main::Account*> _account;
+	const not_null<Main::Account*> _account;
+	std::optional<MTP::Sender> _api;
 
 	Ui::Animations::Simple _a_show;
 	bool _showBack = false;
diff --git a/Telegram/SourceFiles/lang/lang_cloud_manager.cpp b/Telegram/SourceFiles/lang/lang_cloud_manager.cpp
index c025588fc..e081abe20 100644
--- a/Telegram/SourceFiles/lang/lang_cloud_manager.cpp
+++ b/Telegram/SourceFiles/lang/lang_cloud_manager.cpp
@@ -13,8 +13,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/mtp_instance.h"
 #include "storage/localstorage.h"
 #include "core/application.h"
-#include "apiwrap.h"
 #include "main/main_session.h"
+#include "main/main_account.h"
 #include "boxes/confirm_box.h"
 #include "ui/wrap/padding_wrap.h"
 #include "ui/widgets/labels.h"
@@ -156,11 +156,17 @@ Language ParseLanguage(const MTPLangPackLanguage &data) {
 	});
 }
 
-CloudManager::CloudManager(
-	Instance &langpack,
-	not_null<MTP::Instance*> mtproto)
-: MTP::Sender()
-, _langpack(langpack) {
+CloudManager::CloudManager(Instance &langpack)
+: _langpack(langpack) {
+	Core::App().activeAccount().mtpValue(
+	) | rpl::start_with_next([=](MTP::Instance *instance) {
+		if (instance) {
+			_api.emplace(instance);
+			resendRequests();
+		} else {
+			_api.reset();
+		}
+	}, _lifetime);
 }
 
 Pack CloudManager::packTypeFromId(const QString &id) const {
@@ -195,7 +201,10 @@ mtpRequestId CloudManager::packRequestId(Pack pack) const {
 }
 
 void CloudManager::requestLangPackDifference(Pack pack) {
-	request(base::take(packRequestId(pack))).cancel();
+	if (!_api) {
+		return;
+	}
+	_api->request(base::take(packRequestId(pack))).cancel();
 	if (_langpack.isCustom()) {
 		return;
 	}
@@ -206,7 +215,7 @@ void CloudManager::requestLangPackDifference(Pack pack) {
 		return;
 	}
 	if (version > 0) {
-		packRequestId(pack) = request(MTPlangpack_GetDifference(
+		packRequestId(pack) = _api->request(MTPlangpack_GetDifference(
 			MTP_string(CloudLangPackName()),
 			MTP_string(code),
 			MTP_int(version)
@@ -217,7 +226,7 @@ void CloudManager::requestLangPackDifference(Pack pack) {
 			packRequestId(pack) = 0;
 		}).send();
 	} else {
-		packRequestId(pack) = request(MTPlangpack_GetLangPack(
+		packRequestId(pack) = _api->request(MTPlangpack_GetLangPack(
 			MTP_string(CloudLangPackName()),
 			MTP_string(code)
 		)).done([=](const MTPLangPackDifference &result) {
@@ -284,7 +293,12 @@ void CloudManager::applyLangPackDifference(
 }
 
 void CloudManager::requestLanguageList() {
-	_languagesRequestId = request(MTPlangpack_GetLanguages(
+	if (!_api) {
+		_languagesRequestId = -1;
+		return;
+	}
+	_api->request(base::take(_languagesRequestId)).cancel();
+	_languagesRequestId = _api->request(MTPlangpack_GetLanguages(
 		MTP_string(CloudLangPackName())
 	)).done([=](const MTPVector<MTPLangPackLanguage> &result) {
 		auto languages = Languages();
@@ -402,10 +416,20 @@ void CloudManager::requestLanguageAndSwitch(
 		return;
 	}
 
-	request(_switchingToLanguageRequest).cancel();
-	_switchingToLanguageRequest = request(MTPlangpack_GetLanguage(
+	_switchingToLanguageId = id;
+	_switchingToLanguageWarning = warning;
+	sendSwitchingToLanguageRequest();
+}
+
+void CloudManager::sendSwitchingToLanguageRequest() {
+	if (!_api) {
+		_switchingToLanguageId = -1;
+		return;
+	}
+	_api->request(_switchingToLanguageRequest).cancel();
+	_switchingToLanguageRequest = _api->request(MTPlangpack_GetLanguage(
 		MTP_string(Lang::CloudLangPackName()),
-		MTP_string(id)
+		MTP_string(_switchingToLanguageId)
 	)).done([=](const MTPLangPackLanguage &result) {
 		_switchingToLanguageRequest = 0;
 		const auto language = Lang::ParseLanguage(result);
@@ -416,7 +440,7 @@ void CloudManager::requestLanguageAndSwitch(
 				performSwitchAndRestart(language);
 			}
 		};
-		if (!warning) {
+		if (!_switchingToLanguageWarning) {
 			finalize();
 			return;
 		}
@@ -438,9 +462,11 @@ void CloudManager::requestLanguageAndSwitch(
 void CloudManager::switchToLanguage(const Language &data) {
 	if (_langpack.id() == data.id && data.id != qstr("#custom")) {
 		return;
+	} else if (!_api) {
+		return;
 	}
 
-	request(_switchingToLanguageRequest).cancel();
+	_api->request(base::take(_getKeysForSwitchRequestId)).cancel();
 	if (data.id == qstr("#custom")) {
 		performSwitchToCustom();
 	} else if (canApplyWithoutRestart(data.id)) {
@@ -449,12 +475,12 @@ void CloudManager::switchToLanguage(const Language &data) {
 		QVector<MTPstring> keys;
 		keys.reserve(3);
 		keys.push_back(MTP_string("lng_sure_save_language"));
-		_switchingToLanguageRequest = request(MTPlangpack_GetStrings(
+		_getKeysForSwitchRequestId = _api->request(MTPlangpack_GetStrings(
 			MTP_string(Lang::CloudLangPackName()),
 			MTP_string(data.id),
 			MTP_vector<MTPstring>(std::move(keys))
 		)).done([=](const MTPVector<MTPLangPackString> &result) {
-			_switchingToLanguageRequest = 0;
+			_getKeysForSwitchRequestId = 0;
 			const auto values = Instance::ParseStrings(result);
 			const auto getValue = [&](ushort key) {
 				auto it = values.find(key);
@@ -473,7 +499,7 @@ void CloudManager::switchToLanguage(const Language &data) {
 					[=] { performSwitchAndRestart(data); }),
 				Ui::LayerOption::KeepOther);
 		}).fail([=](const RPCError &error) {
-			_switchingToLanguageRequest = 0;
+			_getKeysForSwitchRequestId = 0;
 		}).send();
 	}
 }
@@ -481,7 +507,7 @@ void CloudManager::switchToLanguage(const Language &data) {
 void CloudManager::performSwitchToCustom() {
 	auto filter = qsl("Language files (*.strings)");
 	auto title = qsl("Choose language .strings file");
-	FileDialog::GetOpenPath(Core::App().getFileDialogParent(), title, filter, [weak = base::make_weak(this)](const FileDialog::OpenResult &result) {
+	FileDialog::GetOpenPath(Core::App().getFileDialogParent(), title, filter, [=, weak = base::make_weak(this)](const FileDialog::OpenResult &result) {
 		if (!weak || result.paths.isEmpty()) {
 			return;
 		}
@@ -491,9 +517,13 @@ void CloudManager::performSwitchToCustom() {
 			filePath,
 			{ tr::lng_sure_save_language.base });
 		if (loader.errors().isEmpty()) {
-			weak->request(weak->_switchingToLanguageRequest).cancel();
-			if (weak->canApplyWithoutRestart(qsl("#custom"))) {
-				weak->_langpack.switchToCustomFile(filePath);
+			if (_api) {
+				_api->request(
+					base::take(_switchingToLanguageRequest)
+				).cancel();
+			}
+			if (canApplyWithoutRestart(qsl("#custom"))) {
+				_langpack.switchToCustomFile(filePath);
 			} else {
 				const auto values = loader.found();
 				const auto getValue = [&](ushort key) {
@@ -506,7 +536,7 @@ void CloudManager::performSwitchToCustom() {
 					+ "\n\n"
 					 + getValue(tr::lng_sure_save_language.base);
 				const auto change = [=] {
-					weak->_langpack.switchToCustomFile(filePath);
+					_langpack.switchToCustomFile(filePath);
 					App::restart();
 				};
 				Ui::show(
@@ -572,9 +602,25 @@ void CloudManager::switchLangPackId(const Language &data) {
 
 void CloudManager::changeIdAndReInitConnection(const Language &data) {
 	_langpack.switchToId(data);
+	if (_api) {
+		const auto mtproto = _api->instance();
+		mtproto->reInitConnection(mtproto->mainDcId());
+	}
+}
 
-	auto mtproto = requestMTP();
-	mtproto->reInitConnection(mtproto->mainDcId());
+void CloudManager::resendRequests() {
+	if (packRequestId(Pack::Base)) {
+		requestLangPackDifference(Pack::Base);
+	}
+	if (packRequestId(Pack::Current)) {
+		requestLangPackDifference(Pack::Current);
+	}
+	if (_languagesRequestId) {
+		requestLanguageList();
+	}
+	if (_switchingToLanguageRequest) {
+		sendSwitchingToLanguageRequest();
+	}
 }
 
 CloudManager &CurrentCloudManager() {
diff --git a/Telegram/SourceFiles/lang/lang_cloud_manager.h b/Telegram/SourceFiles/lang/lang_cloud_manager.h
index f95b4854a..d8b53deb8 100644
--- a/Telegram/SourceFiles/lang/lang_cloud_manager.h
+++ b/Telegram/SourceFiles/lang/lang_cloud_manager.h
@@ -22,9 +22,9 @@ struct Language;
 
 Language ParseLanguage(const MTPLangPackLanguage &data);
 
-class CloudManager : public base::has_weak_ptr, private MTP::Sender, private base::Subscriber {
+class CloudManager : public base::has_weak_ptr, private base::Subscriber {
 public:
-	CloudManager(Instance &langpack, not_null<MTP::Instance*> mtproto);
+	explicit CloudManager(Instance &langpack);
 
 	using Languages = std::vector<Language>;
 
@@ -72,6 +72,10 @@ private:
 	void switchLangPackId(const Language &data);
 	void changeIdAndReInitConnection(const Language &data);
 
+	void sendSwitchingToLanguageRequest();
+	void resendRequests();
+
+	std::optional<MTP::Sender> _api;
 	Instance &_langpack;
 	Languages _languages;
 	base::Observable<void> _languagesChanged;
@@ -87,6 +91,12 @@ private:
 	base::Observable<void> _firstLanguageSuggestion;
 
 	mtpRequestId _switchingToLanguageRequest = 0;
+	QString _switchingToLanguageId;
+	bool _switchingToLanguageWarning = false;
+
+	mtpRequestId _getKeysForSwitchRequestId = 0;
+
+	rpl::lifetime _lifetime;
 
 };
 
diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index faa11e7cc..fcc3a8ad6 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -498,16 +498,16 @@ rpl::producer<> Account::configUpdates() const {
 }
 
 void Account::resetAuthorizationKeys() {
+	_mtpValue = nullptr;
 	_mtp = nullptr;
-	_mtpValue = _mtp.get();
 	startMtp();
 	Local::writeMtpData();
 }
 
 void Account::clearMtp() {
+	_mtpValue = nullptr;
 	_mtp = nullptr;
 	_mtpForKeysDestroy = nullptr;
-	_mtpValue = _mtp.get();
 }
 
 } // namespace Main
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
index ced2d5b1d..95b5404da 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
@@ -29,7 +29,8 @@ LoaderMtproto::LoaderMtproto(
 , _location(location)
 , _dcId(location.dcId())
 , _size(size)
-, _origin(origin) {
+, _origin(origin)
+, _api(_owner->api().instance()) {
 }
 
 LoaderMtproto::~LoaderMtproto() {
@@ -68,7 +69,7 @@ void LoaderMtproto::stop() {
 	crl::on_main(this, [=] {
 		ranges::for_each(
 			base::take(_requests),
-			_sender.requestCanceller(),
+			_api.requestCanceller(),
 			&base::flat_map<int, mtpRequestId>::value_type::second);
 		_requested.clear();
 	});
@@ -82,7 +83,7 @@ void LoaderMtproto::cancel(int offset) {
 
 void LoaderMtproto::cancelForOffset(int offset) {
 	if (const auto requestId = _requests.take(offset)) {
-		_sender.request(*requestId).cancel();
+		_api.request(*requestId).cancel();
 		sendNext();
 	} else {
 		_requested.remove(offset);
@@ -122,7 +123,7 @@ void LoaderMtproto::sendNext() {
 	changeRequestedAmount(index, kPartSize);
 
 	const auto usedFileReference = _location.fileReference();
-	const auto id = _sender.request(MTPupload_GetFile(
+	const auto id = _api.request(MTPupload_GetFile(
 		MTP_flags(0),
 		_location.tl(Auth().userId()),
 		MTP_int(offset),
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
index 755e63dd9..bd9d1ef0e 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
@@ -70,7 +70,7 @@ private:
 	const int _size = 0;
 	const Data::FileOrigin _origin;
 
-	MTP::Sender _sender;
+	MTP::Sender _api;
 
 	PriorityQueue _requested;
 	base::flat_map<int, mtpRequestId> _requests;
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 888728b9d..5bef40a88 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -262,7 +262,7 @@ Instance::Private::Private(
 	not_null<Instance*> instance,
 	not_null<DcOptions*> options,
 	Instance::Mode mode)
-: Sender()
+: Sender(instance)
 , _instance(instance)
 , _dcOptions(options)
 , _mode(mode) {
diff --git a/Telegram/SourceFiles/mtproto/sender.h b/Telegram/SourceFiles/mtproto/sender.h
index 3e1fd6c71..6d91b2914 100644
--- a/Telegram/SourceFiles/mtproto/sender.h
+++ b/Telegram/SourceFiles/mtproto/sender.h
@@ -14,9 +14,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace MTP {
 
-class Instance;
-Instance *MainInstance();
-
 class Sender {
 	class RequestBuilder {
 	public:
@@ -104,11 +101,11 @@ class Sender {
 
 			bool operator()(mtpRequestId requestId, const RPCError &error) override {
 				if (_skipPolicy == FailSkipPolicy::Simple) {
-					if (MTP::isDefaultHandledError(error)) {
+					if (isDefaultHandledError(error)) {
 						return false;
 					}
 				} else if (_skipPolicy == FailSkipPolicy::HandleFlood) {
-					if (MTP::isDefaultHandledError(error) && !MTP::isFloodError(error)) {
+					if (isDefaultHandledError(error) && !isFloodError(error)) {
 						return false;
 					}
 				}
@@ -195,7 +192,12 @@ class Sender {
 	};
 
 public:
-	Sender() noexcept {
+	explicit Sender(not_null<Instance*> instance) noexcept
+	: _instance(instance) {
+	}
+
+	[[nodiscard]] not_null<Instance*> instance() const {
+		return _instance;
 	}
 
 	template <typename Request>
@@ -245,7 +247,7 @@ public:
 		}
 
 		mtpRequestId send() {
-			const auto id = MainInstance()->send(
+			const auto id = sender()->instance()->send(
 				_request,
 				takeOnDone(),
 				takeOnFail(),
@@ -293,16 +295,13 @@ public:
 	}
 
 	void requestSendDelayed() {
-		MainInstance()->sendAnything();
+		_instance->sendAnything();
 	}
 	void requestCancellingDiscard() {
 		for (auto &request : _requests) {
 			request.handled();
 		}
 	}
-	not_null<Instance*> requestMTP() const {
-		return MainInstance();
-	}
 
 private:
 	class RequestWrap {
@@ -392,6 +391,7 @@ private:
 		}
 	}
 
+	const not_null<Instance*> _instance;
 	base::flat_set<RequestWrap, RequestWrapComparator> _requests;
 
 };
diff --git a/Telegram/SourceFiles/passport/passport_form_controller.cpp b/Telegram/SourceFiles/passport/passport_form_controller.cpp
index d43349366..6d4e2c0fb 100644
--- a/Telegram/SourceFiles/passport/passport_form_controller.cpp
+++ b/Telegram/SourceFiles/passport/passport_form_controller.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/file_upload.h"
 #include "storage/file_download.h"
 #include "app.h"
+#include "apiwrap.h"
 
 #include <QtCore/QJsonDocument>
 #include <QtCore/QJsonArray>
@@ -620,6 +621,7 @@ FormController::FormController(
 	not_null<Window::SessionController*> controller,
 	const FormRequest &request)
 : _controller(controller)
+, _api(_controller->session().api().instance())
 , _request(PreprocessRequest(request))
 , _shortPollTimer([=] { reloadPassword(); })
 , _view(std::make_unique<PanelController>(this)) {
@@ -741,7 +743,7 @@ std::vector<not_null<const Value*>> FormController::submitGetErrors() {
 		credentialsEncryptedData.secret,
 		bytes::make_span(_request.publicKey.toUtf8()));
 
-	_submitRequestId = request(MTPaccount_AcceptAuthorization(
+	_submitRequestId = _api.request(MTPaccount_AcceptAuthorization(
 		MTP_int(_request.botId),
 		MTP_string(_request.scope),
 		MTP_string(_request.publicKey),
@@ -808,8 +810,8 @@ void FormController::requestPasswordData(mtpRequestId &guard) {
 		return passwordServerError();
 	}
 
-	request(base::take(guard)).cancel();
-	guard = request(
+	_api.request(base::take(guard)).cancel();
+	guard = _api.request(
 		MTPaccount_GetPassword()
 	).done([=, &guard](const MTPaccount_Password &result) {
 		guard = 0;
@@ -843,7 +845,7 @@ void FormController::submitPassword(
 		const Core::CloudPasswordResult &check,
 		const QByteArray &password,
 		bool submitSaved) {
-	_passwordCheckRequestId = request(MTPaccount_GetPasswordSettings(
+	_passwordCheckRequestId = _api.request(MTPaccount_GetPasswordSettings(
 		check.result
 	)).handleFloodErrors(
 	).done([=](const MTPaccount_PasswordSettings &result) {
@@ -936,7 +938,7 @@ void FormController::checkSavedPasswordSettings(
 void FormController::checkSavedPasswordSettings(
 		const Core::CloudPasswordResult &check,
 		const SavedCredentials &credentials) {
-	_passwordCheckRequestId = request(MTPaccount_GetPasswordSettings(
+	_passwordCheckRequestId = _api.request(MTPaccount_GetPasswordSettings(
 		check.result
 	)).done([=](const MTPaccount_PasswordSettings &result) {
 		Expects(result.type() == mtpc_account_passwordSettings);
@@ -982,7 +984,7 @@ void FormController::recoverPassword() {
 	} else if (_recoverRequestId) {
 		return;
 	}
-	_recoverRequestId = request(MTPauth_RequestPasswordRecovery(
+	_recoverRequestId = _api.request(MTPauth_RequestPasswordRecovery(
 	)).done([=](const MTPauth_PasswordRecovery &result) {
 		Expects(result.type() == mtpc_auth_passwordRecovery);
 
@@ -1024,7 +1026,7 @@ void FormController::cancelPassword() {
 	if (_passwordRequestId) {
 		return;
 	}
-	_passwordRequestId = request(MTPaccount_CancelPasswordEmail(
+	_passwordRequestId = _api.request(MTPaccount_CancelPasswordEmail(
 	)).done([=](const MTPBool &result) {
 		_passwordRequestId = 0;
 		reloadPassword();
@@ -1093,7 +1095,7 @@ void FormController::resetSecret(
 		const Core::CloudPasswordResult &check,
 		const bytes::vector &password) {
 	using Flag = MTPDaccount_passwordInputSettings::Flag;
-	_saveSecretRequestId = request(MTPaccount_UpdatePasswordSettings(
+	_saveSecretRequestId = _api.request(MTPaccount_UpdatePasswordSettings(
 		check.result,
 		MTP_account_passwordInputSettings(
 			MTP_flags(Flag::f_new_secure_settings),
@@ -1625,7 +1627,7 @@ void FormController::verify(
 	nonconst->verification.requestId = [&] {
 		switch (nonconst->type) {
 		case Value::Type::Phone:
-			return request(MTPaccount_VerifyPhone(
+			return _api.request(MTPaccount_VerifyPhone(
 				MTP_string(getPhoneFromValue(nonconst)),
 				MTP_string(nonconst->verification.phoneCodeHash),
 				MTP_string(prepared)
@@ -1643,7 +1645,7 @@ void FormController::verify(
 				}
 			}).send();
 		case Value::Type::Email:
-			return request(MTPaccount_VerifyEmail(
+			return _api.request(MTPaccount_VerifyEmail(
 				MTP_string(getEmailFromValue(nonconst)),
 				MTP_string(prepared)
 			)).done([=](const MTPBool &result) {
@@ -1825,7 +1827,7 @@ void FormController::cancelValueVerification(not_null<const Value*> value) {
 void FormController::clearValueVerification(not_null<Value*> value) {
 	const auto was = (value->verification.codeLength != 0);
 	if (const auto requestId = base::take(value->verification.requestId)) {
-		request(requestId).cancel();
+		_api.request(requestId).cancel();
 	}
 	value->verification = Verification();
 	if (was) {
@@ -1872,7 +1874,7 @@ void FormController::deleteValueEdit(not_null<const Value*> value) {
 	}
 
 	const auto nonconst = findValue(value);
-	nonconst->saveRequestId = request(MTPaccount_DeleteSecureValue(
+	nonconst->saveRequestId = _api.request(MTPaccount_DeleteSecureValue(
 		MTP_vector<MTPSecureValueType>(1, ConvertType(nonconst->type))
 	)).done([=](const MTPBool &result) {
 		resetValue(*nonconst);
@@ -2019,7 +2021,7 @@ void FormController::sendSaveRequest(
 		const MTPInputSecureValue &data) {
 	Expects(value->saveRequestId == 0);
 
-	value->saveRequestId = request(MTPaccount_SaveSecureValue(
+	value->saveRequestId = _api.request(MTPaccount_SaveSecureValue(
 		data,
 		MTP_long(_secretId)
 	)).done([=](const MTPSecureValue &result) {
@@ -2092,7 +2094,7 @@ QString FormController::getPlainTextFromValue(
 }
 
 void FormController::startPhoneVerification(not_null<Value*> value) {
-	value->verification.requestId = request(MTPaccount_SendVerifyPhoneCode(
+	value->verification.requestId = _api.request(MTPaccount_SendVerifyPhoneCode(
 		MTP_string(getPhoneFromValue(value)),
 		MTP_codeSettings(MTP_flags(0))
 	)).done([=](const MTPauth_SentCode &result) {
@@ -2149,7 +2151,7 @@ void FormController::startPhoneVerification(not_null<Value*> value) {
 }
 
 void FormController::startEmailVerification(not_null<Value*> value) {
-	value->verification.requestId = request(MTPaccount_SendVerifyEmailCode(
+	value->verification.requestId = _api.request(MTPaccount_SendVerifyEmailCode(
 		MTP_string(getEmailFromValue(value))
 	)).done([=](const MTPaccount_SentEmailCode &result) {
 		Expects(result.type() == mtpc_account_sentEmailCode);
@@ -2171,7 +2173,7 @@ void FormController::requestPhoneCall(not_null<Value*> value) {
 
 	value->verification.call->setStatus(
 		{ SentCodeCall::State::Calling, 0 });
-	request(MTPauth_ResendCode(
+	_api.request(MTPauth_ResendCode(
 		MTP_string(getPhoneFromValue(value)),
 		MTP_string(value->verification.phoneCodeHash)
 	)).done([=](const MTPauth_SentCode &code) {
@@ -2222,7 +2224,7 @@ void FormController::saveSecret(
 		saved.hashForSecret);
 
 	using Flag = MTPDaccount_passwordInputSettings::Flag;
-	_saveSecretRequestId = request(MTPaccount_UpdatePasswordSettings(
+	_saveSecretRequestId = _api.request(MTPaccount_UpdatePasswordSettings(
 		check.result,
 		MTP_account_passwordInputSettings(
 			MTP_flags(Flag::f_new_secure_settings),
@@ -2270,7 +2272,7 @@ void FormController::requestForm() {
 		formFail(NonceNameByScope(_request.scope).toUpper() + "_EMPTY");
 		return;
 	}
-	_formRequestId = request(MTPaccount_GetAuthorizationForm(
+	_formRequestId = _api.request(MTPaccount_GetAuthorizationForm(
 		MTP_int(_request.botId),
 		MTP_string(_request.scope),
 		MTP_string(_request.publicKey)
@@ -2478,7 +2480,7 @@ void FormController::formDone(const MTPaccount_AuthorizationForm &result) {
 
 void FormController::requestConfig() {
 	const auto hash = ConfigInstance().hash;
-	_configRequestId = request(MTPhelp_GetPassportConfig(
+	_configRequestId = _api.request(MTPhelp_GetPassportConfig(
 		MTP_int(hash)
 	)).done([=](const MTPhelp_PassportConfig &result) {
 		_configRequestId = 0;
@@ -2555,7 +2557,7 @@ void FormController::requestPassword() {
 	if (_passwordRequestId) {
 		return;
 	}
-	_passwordRequestId = request(MTPaccount_GetPassword(
+	_passwordRequestId = _api.request(MTPaccount_GetPassword(
 	)).done([=](const MTPaccount_Password &result) {
 		_passwordRequestId = 0;
 		passwordDone(result);
diff --git a/Telegram/SourceFiles/passport/passport_form_controller.h b/Telegram/SourceFiles/passport/passport_form_controller.h
index b7f56d467..4ae25ac65 100644
--- a/Telegram/SourceFiles/passport/passport_form_controller.h
+++ b/Telegram/SourceFiles/passport/passport_form_controller.h
@@ -318,7 +318,7 @@ struct FileKey {
 
 };
 
-class FormController : private MTP::Sender, public base::has_weak_ptr {
+class FormController : public base::has_weak_ptr {
 public:
 	FormController(
 		not_null<Window::SessionController*> controller,
@@ -512,6 +512,7 @@ private:
 	void shortPollEmailConfirmation();
 
 	not_null<Window::SessionController*> _controller;
+	MTP::Sender _api;
 	FormRequest _request;
 	UserData *_bot = nullptr;
 
diff --git a/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp b/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
index 6a15f9733..5368c1ece 100644
--- a/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
+++ b/Telegram/SourceFiles/settings/settings_privacy_controllers.cpp
@@ -180,7 +180,8 @@ AdminLog::OwnedItem GenerateForwardedItem(
 
 BlockedBoxController::BlockedBoxController(
 	not_null<Window::SessionController*> window)
-: _window(window) {
+: _window(window)
+, _api(_window->session().api().instance()) {
 }
 
 Main::Session &BlockedBoxController::session() const {
@@ -220,7 +221,7 @@ void BlockedBoxController::loadMoreRows() {
 		return;
 	}
 
-	_loadRequestId = request(MTPcontacts_GetBlocked(
+	_loadRequestId = _api.request(MTPcontacts_GetBlocked(
 		MTP_int(_offset),
 		MTP_int(kBlockedPerPage)
 	)).done([=](const MTPcontacts_Blocked &result) {
diff --git a/Telegram/SourceFiles/settings/settings_privacy_controllers.h b/Telegram/SourceFiles/settings/settings_privacy_controllers.h
index 1ba146bf8..461b97b25 100644
--- a/Telegram/SourceFiles/settings/settings_privacy_controllers.h
+++ b/Telegram/SourceFiles/settings/settings_privacy_controllers.h
@@ -16,8 +16,7 @@ namespace Settings {
 
 class BlockedBoxController
 	: public PeerListController
-	, private base::Subscriber
-	, private MTP::Sender {
+	, private base::Subscriber {
 public:
 	explicit BlockedBoxController(
 		not_null<Window::SessionController*> window);
@@ -39,6 +38,7 @@ private:
 	std::unique_ptr<PeerListRow> createRow(not_null<UserData*> user) const;
 
 	const not_null<Window::SessionController*> _window;
+	MTP::Sender _api;
 
 	int _offset = 0;
 	mtpRequestId _loadRequestId = 0;
diff --git a/Telegram/SourceFiles/support/support_helper.cpp b/Telegram/SourceFiles/support/support_helper.cpp
index 56e2d717d..00d3cf6dc 100644
--- a/Telegram/SourceFiles/support/support_helper.cpp
+++ b/Telegram/SourceFiles/support/support_helper.cpp
@@ -288,10 +288,11 @@ TimeId OccupiedBySomeoneTill(History *history) {
 
 Helper::Helper(not_null<Main::Session*> session)
 : _session(session)
+, _api(_session->api().instance())
 , _templates(_session)
 , _reoccupyTimer([=] { reoccupy(); })
 , _checkOccupiedTimer([=] { checkOccupiedChats(); }) {
-	request(MTPhelp_GetSupportName(
+	_api.request(MTPhelp_GetSupportName(
 	)).done([=](const MTPhelp_SupportName &result) {
 		result.match([&](const MTPDhelp_supportName &data) {
 			setSupportName(qs(data.vname()));
@@ -422,7 +423,7 @@ bool Helper::isOccupiedBySomeone(History *history) const {
 }
 
 void Helper::refreshInfo(not_null<UserData*> user) {
-	request(MTPhelp_GetUserInfo(
+	_api.request(MTPhelp_GetUserInfo(
 		user->inputUser
 	)).done([=](const MTPhelp_UserInfo &result) {
 		applyInfo(user, result);
@@ -531,7 +532,7 @@ void Helper::saveInfo(
 			return;
 		} else {
 			i->second.data = text;
-			request(base::take(i->second.requestId)).cancel();
+			_api.request(base::take(i->second.requestId)).cancel();
 		}
 	} else {
 		_userInfoSaving.emplace(user, SavingInfo{ text });
@@ -545,7 +546,7 @@ void Helper::saveInfo(
 	const auto entities = Api::EntitiesToMTP(
 		text.entities,
 		Api::ConvertOption::SkipLocal);
-	_userInfoSaving[user].requestId = request(MTPhelp_EditUserInfo(
+	_userInfoSaving[user].requestId = _api.request(MTPhelp_EditUserInfo(
 		user->inputUser,
 		MTP_string(text.text),
 		entities
diff --git a/Telegram/SourceFiles/support/support_helper.h b/Telegram/SourceFiles/support/support_helper.h
index e3cde4971..46cf1b468 100644
--- a/Telegram/SourceFiles/support/support_helper.h
+++ b/Telegram/SourceFiles/support/support_helper.h
@@ -39,7 +39,7 @@ inline bool operator!=(const UserInfo &a, const UserInfo &b) {
 	return !(a == b);
 }
 
-class Helper : private MTP::Sender {
+class Helper final {
 public:
 	explicit Helper(not_null<Main::Session*> session);
 
@@ -87,6 +87,7 @@ private:
 		Fn<void(bool success)> done);
 
 	not_null<Main::Session*> _session;
+	MTP::Sender _api;
 	Templates _templates;
 	QString _supportName;
 	QString _supportNameNormalized;

From 55f83129b7373b7a192c6413658134722ab597e6 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 27 Nov 2019 11:33:18 +0300
Subject: [PATCH 60/91] Remove Q_OBJECTs from Intro.

---
 Telegram/SourceFiles/intro/intro_qr.h        |  2 +-
 Telegram/SourceFiles/intro/introcode.cpp     | 46 +++++++++-------
 Telegram/SourceFiles/intro/introcode.h       | 20 +++----
 Telegram/SourceFiles/intro/introphone.cpp    | 17 +++---
 Telegram/SourceFiles/intro/introphone.h      | 13 ++---
 Telegram/SourceFiles/intro/intropwdcheck.cpp | 58 ++++++--------------
 Telegram/SourceFiles/intro/intropwdcheck.h   | 17 ++----
 Telegram/SourceFiles/intro/introsignup.cpp   | 45 +++------------
 Telegram/SourceFiles/intro/introsignup.h     | 11 +---
 9 files changed, 81 insertions(+), 148 deletions(-)

diff --git a/Telegram/SourceFiles/intro/intro_qr.h b/Telegram/SourceFiles/intro/intro_qr.h
index 6bad082fb..a912897d6 100644
--- a/Telegram/SourceFiles/intro/intro_qr.h
+++ b/Telegram/SourceFiles/intro/intro_qr.h
@@ -22,7 +22,7 @@ class FlatLabel;
 namespace Intro {
 namespace details {
 
-class QrWidget : public Step {
+class QrWidget final : public Step {
 public:
 	QrWidget(
 		QWidget *parent,
diff --git a/Telegram/SourceFiles/intro/introcode.cpp b/Telegram/SourceFiles/intro/introcode.cpp
index c8ba9ab8a..14d3ae07c 100644
--- a/Telegram/SourceFiles/intro/introcode.cpp
+++ b/Telegram/SourceFiles/intro/introcode.cpp
@@ -82,17 +82,15 @@ CodeWidget::CodeWidget(
 : Step(parent, account, data)
 , _noTelegramCode(this, tr::lng_code_no_telegram(tr::now), st::introLink)
 , _code(this, st::introCode, tr::lng_code_ph())
-, _callTimer(this)
+, _callTimer([=] { sendCall(); })
 , _callStatus(getData()->callStatus)
 , _callTimeout(getData()->callTimeout)
 , _callLabel(this, st::introDescription)
-, _checkRequest(this) {
+, _checkRequestTimer([=] { checkRequest(); }) {
 	subscribe(Lang::Current().updated(), [this] { refreshLang(); });
 
-	connect(_code, SIGNAL(changed()), this, SLOT(onInputChange()));
-	connect(_callTimer, SIGNAL(timeout()), this, SLOT(onSendCall()));
-	connect(_checkRequest, SIGNAL(timeout()), this, SLOT(onCheckRequest()));
-	_noTelegramCode->addClickHandler([=] { onNoTelegramCode(); });
+	connect(_code, &CodeInput::changed, [=] { codeChanged(); });
+	_noTelegramCode->addClickHandler([=] { noTelegramCode(); });
 
 	_code->setDigitsCountMax(getData()->codeLength);
 
@@ -101,7 +99,9 @@ CodeWidget::CodeWidget(
 }
 
 void CodeWidget::refreshLang() {
-	if (_noTelegramCode) _noTelegramCode->setText(tr::lng_code_no_telegram(tr::now));
+	if (_noTelegramCode) {
+		_noTelegramCode->setText(tr::lng_code_no_telegram(tr::now));
+	}
 	updateDescText();
 	updateControlsGeometry();
 }
@@ -117,13 +117,13 @@ void CodeWidget::updateDescText() {
 			Ui::Text::RichLangValue));
 	if (getData()->codeByTelegram) {
 		_noTelegramCode->show();
-		_callTimer->stop();
+		_callTimer.cancel();
 	} else {
 		_noTelegramCode->hide();
 		_callStatus = getData()->callStatus;
 		_callTimeout = getData()->callTimeout;
-		if (_callStatus == CallStatus::Waiting && !_callTimer->isActive()) {
-			_callTimer->start(1000);
+		if (_callStatus == CallStatus::Waiting && !_callTimer.isActive()) {
+			_callTimer.callEach(1000);
 		}
 	}
 	updateCallText();
@@ -199,8 +199,8 @@ void CodeWidget::activate() {
 
 void CodeWidget::finished() {
 	Step::finished();
-	_checkRequest->stop();
-	_callTimer->stop();
+	_checkRequestTimer.cancel();
+	_callTimer.cancel();
 	rpcInvalidate();
 
 	cancelled();
@@ -215,10 +215,10 @@ void CodeWidget::cancelled() {
 }
 
 void CodeWidget::stopCheck() {
-	_checkRequest->stop();
+	_checkRequestTimer.cancel();
 }
 
-void CodeWidget::onCheckRequest() {
+void CodeWidget::checkRequest() {
 	auto status = MTP::state(_sentRequest);
 	if (status < 0) {
 		auto leftms = -status;
@@ -278,7 +278,7 @@ bool CodeWidget::codeSubmitFail(const RPCError &error) {
 		showCodeError(tr::lng_bad_code());
 		return true;
 	} else if (err == qstr("SESSION_PASSWORD_NEEDED")) {
-		_checkRequest->start(1000);
+		_checkRequestTimer.callEach(1000);
 		_sentRequest = MTP::send(
 			MTPaccount_GetPassword(),
 			rpcDone(&CodeWidget::gotPassword),
@@ -293,17 +293,21 @@ bool CodeWidget::codeSubmitFail(const RPCError &error) {
 	return false;
 }
 
-void CodeWidget::onInputChange() {
+void CodeWidget::codeChanged() {
 	hideError();
 	submit();
 }
 
-void CodeWidget::onSendCall() {
+void CodeWidget::sendCall() {
 	if (_callStatus == CallStatus::Waiting) {
 		if (--_callTimeout <= 0) {
 			_callStatus = CallStatus::Calling;
-			_callTimer->stop();
-			_callRequestId = MTP::send(MTPauth_ResendCode(MTP_string(getData()->phone), MTP_bytes(getData()->phoneHash)), rpcDone(&CodeWidget::callDone));
+			_callTimer.cancel();
+			_callRequestId = MTP::send(
+				MTPauth_ResendCode(
+					MTP_string(getData()->phone),
+					MTP_bytes(getData()->phoneHash)),
+				rpcDone(&CodeWidget::callDone));
 		} else {
 			getData()->callStatus = _callStatus;
 			getData()->callTimeout = _callTimeout;
@@ -369,7 +373,7 @@ void CodeWidget::submit() {
 
 	hideError();
 
-	_checkRequest->start(1000);
+	_checkRequestTimer.callEach(1000);
 
 	_sentCode = text;
 	getData()->pwdRequest = Core::CloudPasswordCheckRequest();
@@ -385,7 +389,7 @@ void CodeWidget::submit() {
 		rpcFail(&CodeWidget::codeSubmitFail));
 }
 
-void CodeWidget::onNoTelegramCode() {
+void CodeWidget::noTelegramCode() {
 	if (_noTelegramCodeRequestId) {
 		return;
 	}
diff --git a/Telegram/SourceFiles/intro/introcode.h b/Telegram/SourceFiles/intro/introcode.h
index d02ed7d82..ddc72cdf1 100644
--- a/Telegram/SourceFiles/intro/introcode.h
+++ b/Telegram/SourceFiles/intro/introcode.h
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "intro/intro_step.h"
 #include "ui/widgets/input_fields.h"
 #include "intro/introwidget.h"
+#include "base/timer.h"
 
 namespace Ui {
 class RoundButton;
@@ -39,9 +40,7 @@ private:
 
 };
 
-class CodeWidget : public Step {
-	Q_OBJECT
-
+class CodeWidget final : public Step {
 public:
 	CodeWidget(
 		QWidget *parent,
@@ -62,13 +61,12 @@ public:
 protected:
 	void resizeEvent(QResizeEvent *e) override;
 
-private slots:
-	void onNoTelegramCode();
-	void onInputChange();
-	void onSendCall();
-	void onCheckRequest();
-
 private:
+	void noTelegramCode();
+	void codeChanged();
+	void sendCall();
+	void checkRequest();
+
 	int errorTop() const override;
 
 	void updateCallText();
@@ -94,13 +92,13 @@ private:
 	QString _sentCode;
 	mtpRequestId _sentRequest = 0;
 
-	object_ptr<QTimer> _callTimer;
+	base::Timer _callTimer;
 	CallStatus _callStatus = CallStatus();
 	int _callTimeout;
 	mtpRequestId _callRequestId = 0;
 	object_ptr<Ui::FlatLabel> _callLabel;
 
-	object_ptr<QTimer> _checkRequest;
+	base::Timer _checkRequestTimer;
 
 };
 
diff --git a/Telegram/SourceFiles/intro/introphone.cpp b/Telegram/SourceFiles/intro/introphone.cpp
index fe070bf52..fcf1f2036 100644
--- a/Telegram/SourceFiles/intro/introphone.cpp
+++ b/Telegram/SourceFiles/intro/introphone.cpp
@@ -40,16 +40,15 @@ PhoneWidget::PhoneWidget(
 , _country(this, st::introCountry)
 , _code(this, st::introCountryCode)
 , _phone(this, st::introPhone)
-, _checkRequest(this) {
+, _checkRequestTimer([=] { checkRequest(); }) {
 	connect(_phone, SIGNAL(voidBackspace(QKeyEvent*)), _code, SLOT(startErasing(QKeyEvent*)));
 	connect(_country, SIGNAL(codeChanged(const QString &)), _code, SLOT(codeSelected(const QString &)));
 	connect(_code, SIGNAL(codeChanged(const QString &)), _country, SLOT(onChooseCode(const QString &)));
 	connect(_code, SIGNAL(codeChanged(const QString &)), _phone, SLOT(onChooseCode(const QString &)));
 	connect(_country, SIGNAL(codeChanged(const QString &)), _phone, SLOT(onChooseCode(const QString &)));
 	connect(_code, SIGNAL(addedToNumber(const QString &)), _phone, SLOT(addedToNumber(const QString &)));
-	connect(_phone, SIGNAL(changed()), this, SLOT(onInputChange()));
-	connect(_code, SIGNAL(changed()), this, SLOT(onInputChange()));
-	connect(_checkRequest, SIGNAL(timeout()), this, SLOT(onCheckRequest()));
+	connect(_phone, &Ui::PhonePartInput::changed, [=] { phoneChanged(); });
+	connect(_code, &Ui::CountryCodeInput::changed, [=] { phoneChanged(); });
 
 	setTitleText(tr::lng_phone_title());
 	setDescriptionText(tr::lng_phone_desc());
@@ -85,7 +84,7 @@ void PhoneWidget::countryChanged() {
 	}
 }
 
-void PhoneWidget::onInputChange() {
+void PhoneWidget::phoneChanged() {
 	_changed = true;
 	hidePhoneError();
 }
@@ -102,7 +101,7 @@ void PhoneWidget::submit() {
 
 	hidePhoneError();
 
-	_checkRequest->start(1000);
+	_checkRequestTimer.callEach(1000);
 
 	_sentPhone = phone;
 	account().mtp()->setUserPhone(_sentPhone);
@@ -117,10 +116,10 @@ void PhoneWidget::submit() {
 }
 
 void PhoneWidget::stopCheck() {
-	_checkRequest->stop();
+	_checkRequestTimer.cancel();
 }
 
-void PhoneWidget::onCheckRequest() {
+void PhoneWidget::checkRequest() {
 	auto status = MTP::state(_sentRequest);
 	if (status < 0) {
 		auto leftms = -status;
@@ -209,7 +208,7 @@ void PhoneWidget::activate() {
 
 void PhoneWidget::finished() {
 	Step::finished();
-	_checkRequest->stop();
+	_checkRequestTimer.cancel();
 	rpcInvalidate();
 
 	cancelled();
diff --git a/Telegram/SourceFiles/intro/introphone.h b/Telegram/SourceFiles/intro/introphone.h
index 17ce9abce..cb34386c8 100644
--- a/Telegram/SourceFiles/intro/introphone.h
+++ b/Telegram/SourceFiles/intro/introphone.h
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "ui/countryinput.h"
 #include "intro/intro_step.h"
+#include "base/timer.h"
 
 namespace Ui {
 class PhonePartInput;
@@ -20,9 +21,7 @@ class FlatLabel;
 namespace Intro {
 namespace details {
 
-class PhoneWidget : public Step {
-	Q_OBJECT
-
+class PhoneWidget final : public Step {
 public:
 	PhoneWidget(
 		QWidget *parent,
@@ -44,11 +43,9 @@ public:
 protected:
 	void resizeEvent(QResizeEvent *e) override;
 
-private slots:
-	void onInputChange();
-	void onCheckRequest();
-
 private:
+	void phoneChanged();
+	void checkRequest();
 	void countryChanged();
 
 	void phoneSubmitDone(const MTPauth_SentCode &result);
@@ -69,7 +66,7 @@ private:
 	QString _sentPhone;
 	mtpRequestId _sentRequest = 0;
 
-	object_ptr<QTimer> _checkRequest;
+	base::Timer _checkRequestTimer;
 
 };
 
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.cpp b/Telegram/SourceFiles/intro/intropwdcheck.cpp
index d56320910..fe496fa31 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.cpp
+++ b/Telegram/SourceFiles/intro/intropwdcheck.cpp
@@ -38,17 +38,15 @@ PwdCheckWidget::PwdCheckWidget(
 , _pwdHint(this, st::introPasswordHint)
 , _codeField(this, st::introPassword, tr::lng_signin_code())
 , _toRecover(this, tr::lng_signin_recover(tr::now))
-, _toPassword(this, tr::lng_signin_try_password(tr::now))
-, _checkRequest(this) {
+, _toPassword(this, tr::lng_signin_try_password(tr::now)) {
 	Expects(!!_request);
 
-	subscribe(Lang::Current().updated(), [this] { refreshLang(); });
+	subscribe(Lang::Current().updated(), [=] { refreshLang(); });
 
-	connect(_checkRequest, SIGNAL(timeout()), this, SLOT(onCheckRequest()));
-	_toRecover->addClickHandler([=] { onToRecover(); });
-	_toPassword->addClickHandler([=] { onToPassword(); });
-	connect(_pwdField, SIGNAL(changed()), this, SLOT(onInputChange()));
-	connect(_codeField, SIGNAL(changed()), this, SLOT(onInputChange()));
+	_toRecover->addClickHandler([=] { toRecover(); });
+	_toPassword->addClickHandler([=] { toPassword(); });
+	connect(_pwdField, &Ui::PasswordInput::changed, [=] { hideError(); });
+	connect(_codeField, &Ui::InputField::changed, [=] { hideError(); });
 
 	setTitleText(tr::lng_signin_title());
 	updateDescriptionText();
@@ -120,26 +118,8 @@ void PwdCheckWidget::cancelled() {
 	_api.request(base::take(_sentRequest)).cancel();
 }
 
-void PwdCheckWidget::stopCheck() {
-	_checkRequest->stop();
-}
-
-void PwdCheckWidget::onCheckRequest() {
-	auto status = MTP::state(_sentRequest);
-	if (status < 0) {
-		auto leftms = -status;
-		if (leftms >= 1000) {
-			_api.request(base::take(_sentRequest)).cancel();
-		}
-	}
-	if (!_sentRequest && status == MTP::RequestSent) {
-		stopCheck();
-	}
-}
-
 void PwdCheckWidget::pwdSubmitDone(bool recover, const MTPauth_Authorization &result) {
 	_sentRequest = 0;
-	stopCheck();
 	if (recover) {
 		cSetPasswordRecovered(true);
 	}
@@ -154,14 +134,12 @@ void PwdCheckWidget::pwdSubmitDone(bool recover, const MTPauth_Authorization &re
 void PwdCheckWidget::pwdSubmitFail(const RPCError &error) {
 	if (MTP::isFloodError(error)) {
 		_sentRequest = 0;
-		stopCheck();
 		showError(tr::lng_flood_error());
 		_pwdField->showError();
 		return;
 	}
 
 	_sentRequest = 0;
-	stopCheck();
 	const auto &type = error.type();
 	if (type == qstr("PASSWORD_HASH_INVALID")
 		|| type == qstr("SRP_PASSWORD_CHANGED")) {
@@ -248,7 +226,6 @@ void PwdCheckWidget::codeSubmitFail(const RPCError &error) {
 	}
 
 	_sentRequest = 0;
-	stopCheck();
 	const auto &type = error.type();
 	if (type == qstr("PASSWORD_EMPTY")
 		|| type == qstr("AUTH_KEY_UNREGISTERED")) {
@@ -257,7 +234,7 @@ void PwdCheckWidget::codeSubmitFail(const RPCError &error) {
 		recoverStartFail(error);
 	} else if (type == qstr("PASSWORD_RECOVERY_EXPIRED")) {
 		_emailPattern = QString();
-		onToPassword();
+		toPassword();
 	} else if (type == qstr("CODE_INVALID")) {
 		showError(tr::lng_signin_wrong_code());
 		_codeField->selectAll();
@@ -278,7 +255,6 @@ void PwdCheckWidget::recoverStarted(const MTPauth_PasswordRecovery &result) {
 }
 
 void PwdCheckWidget::recoverStartFail(const RPCError &error) {
-	stopCheck();
 	_pwdField->show();
 	_pwdHint->show();
 	_codeField->hide();
@@ -288,7 +264,7 @@ void PwdCheckWidget::recoverStartFail(const RPCError &error) {
 	hideError();
 }
 
-void PwdCheckWidget::onToRecover() {
+void PwdCheckWidget::toRecover() {
 	if (_hasRecovery) {
 		if (_sentRequest) {
 			_api.request(base::take(_sentRequest)).cancel();
@@ -312,12 +288,16 @@ void PwdCheckWidget::onToRecover() {
 			}).send();
 		}
 	} else {
-		Ui::show(Box<InformBox>(tr::lng_signin_no_email_forgot(tr::now), [this] { showReset(); }));
+		Ui::show(Box<InformBox>(
+			tr::lng_signin_no_email_forgot(tr::now),
+			[=] { showReset(); }));
 	}
 }
 
-void PwdCheckWidget::onToPassword() {
-	Ui::show(Box<InformBox>(tr::lng_signin_cant_email_forgot(tr::now), [this] { showReset(); }));
+void PwdCheckWidget::toPassword() {
+	Ui::show(Box<InformBox>(
+		tr::lng_signin_cant_email_forgot(tr::now),
+		[=] { showReset(); }));
 }
 
 void PwdCheckWidget::showReset() {
@@ -344,12 +324,10 @@ void PwdCheckWidget::updateDescriptionText() {
 		: tr::lng_signin_desc());
 }
 
-void PwdCheckWidget::onInputChange() {
-	hideError();
-}
-
 void PwdCheckWidget::submit() {
-	if (_sentRequest) return;
+	if (_sentRequest) {
+		return;
+	}
 	if (_pwdField->isHidden()) {
 		auto code = _codeField->getLastText().trimmed();
 		if (code.isEmpty()) {
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.h b/Telegram/SourceFiles/intro/intropwdcheck.h
index 98263b410..7b4fac982 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.h
+++ b/Telegram/SourceFiles/intro/intropwdcheck.h
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "intro/intro_step.h"
 #include "core/core_cloud_password.h"
 #include "mtproto/sender.h"
+#include "base/timer.h"
 
 namespace Ui {
 class InputField;
@@ -21,9 +22,7 @@ class LinkButton;
 namespace Intro {
 namespace details {
 
-class PwdCheckWidget : public Step {
-	Q_OBJECT
-
+class PwdCheckWidget final : public Step {
 public:
 	PwdCheckWidget(
 		QWidget *parent,
@@ -39,13 +38,10 @@ public:
 protected:
 	void resizeEvent(QResizeEvent *e) override;
 
-private slots:
-	void onToRecover();
-	void onToPassword();
-	void onInputChange();
-	void onCheckRequest();
-
 private:
+	void toRecover();
+	void toPassword();
+
 	int errorTop() const override;
 
 	void showReset();
@@ -60,7 +56,6 @@ private:
 	void recoverStarted(const MTPauth_PasswordRecovery &result);
 
 	void updateDescriptionText();
-	void stopCheck();
 	void handleSrpIdInvalid();
 	void requestPasswordData();
 	void checkPasswordHash();
@@ -82,8 +77,6 @@ private:
 	object_ptr<Ui::LinkButton> _toPassword;
 	mtpRequestId _sentRequest = 0;
 
-	object_ptr<QTimer> _checkRequest;
-
 };
 
 } // namespace details
diff --git a/Telegram/SourceFiles/intro/introsignup.cpp b/Telegram/SourceFiles/intro/introsignup.cpp
index 9594820b9..9e0c02749 100644
--- a/Telegram/SourceFiles/intro/introsignup.cpp
+++ b/Telegram/SourceFiles/intro/introsignup.cpp
@@ -26,16 +26,15 @@ SignupWidget::SignupWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
 	not_null<Data*> data)
-	: Step(parent, account, data)
-	, _photo(
-		this,
-		tr::lng_settings_crop_profile(tr::now),
-		Ui::UserpicButton::Role::ChangePhoto,
-		st::defaultUserpicButton)
-	, _first(this, st::introName, tr::lng_signup_firstname())
-	, _last(this, st::introName, tr::lng_signup_lastname())
-	, _invertOrder(langFirstNameGoesSecond())
-	, _checkRequest(this) {
+: Step(parent, account, data)
+, _photo(
+	this,
+	tr::lng_settings_crop_profile(tr::now),
+	Ui::UserpicButton::Role::ChangePhoto,
+	st::defaultUserpicButton)
+, _first(this, st::introName, tr::lng_signup_firstname())
+, _last(this, st::introName, tr::lng_signup_lastname())
+, _invertOrder(langFirstNameGoesSecond()) {
 	subscribe(Lang::Current().updated(), [this] { refreshLang(); });
 	if (_invertOrder) {
 		setTabOrder(_last, _first);
@@ -43,8 +42,6 @@ SignupWidget::SignupWidget(
 		setTabOrder(_first, _last);
 	}
 
-	connect(_checkRequest, SIGNAL(timeout()), this, SLOT(onCheckRequest()));
-
 	setErrorCentered(true);
 
 	setTitleText(tr::lng_signup_title());
@@ -107,25 +104,7 @@ void SignupWidget::cancelled() {
 	MTP::cancel(base::take(_sentRequest));
 }
 
-void SignupWidget::stopCheck() {
-	_checkRequest->stop();
-}
-
-void SignupWidget::onCheckRequest() {
-	auto status = MTP::state(_sentRequest);
-	if (status < 0) {
-		auto leftms = -status;
-		if (leftms >= 1000) {
-			MTP::cancel(base::take(_sentRequest));
-		}
-	}
-	if (!_sentRequest && status == MTP::RequestSent) {
-		stopCheck();
-	}
-}
-
 void SignupWidget::nameSubmitDone(const MTPauth_Authorization &result) {
-	stopCheck();
 	auto &d = result.c_auth_authorization();
 	if (d.vuser().type() != mtpc_user || !d.vuser().c_user().is_self()) { // wtf?
 		showError(rpl::single(Lang::Hard::ServerError()));
@@ -136,7 +115,6 @@ void SignupWidget::nameSubmitDone(const MTPauth_Authorization &result) {
 
 bool SignupWidget::nameSubmitFail(const RPCError &error) {
 	if (MTP::isFloodError(error)) {
-		stopCheck();
 		showError(tr::lng_flood_error());
 		if (_invertOrder) {
 			_first->setFocus();
@@ -147,7 +125,6 @@ bool SignupWidget::nameSubmitFail(const RPCError &error) {
 	}
 	if (MTP::isDefaultHandledError(error)) return false;
 
-	stopCheck();
 	auto &err = error.type();
 	if (err == qstr("PHONE_NUMBER_FLOOD")) {
 		Ui::show(Box<InformBox>(tr::lng_error_phone_flood(tr::now)));
@@ -182,10 +159,6 @@ bool SignupWidget::nameSubmitFail(const RPCError &error) {
 	return false;
 }
 
-void SignupWidget::onInputChange() {
-	hideError();
-}
-
 void SignupWidget::submit() {
 	if (_sentRequest) {
 		return;
diff --git a/Telegram/SourceFiles/intro/introsignup.h b/Telegram/SourceFiles/intro/introsignup.h
index f9969d6d4..3867bcbbe 100644
--- a/Telegram/SourceFiles/intro/introsignup.h
+++ b/Telegram/SourceFiles/intro/introsignup.h
@@ -18,9 +18,7 @@ class UserpicButton;
 namespace Intro {
 namespace details {
 
-class SignupWidget : public Step {
-	Q_OBJECT
-
+class SignupWidget final : public Step {
 public:
 	SignupWidget(
 		QWidget *parent,
@@ -37,10 +35,6 @@ public:
 protected:
 	void resizeEvent(QResizeEvent *e) override;
 
-private slots:
-	void onInputChange();
-	void onCheckRequest();
-
 private:
 	void refreshLang();
 	void updateControlsGeometry();
@@ -48,8 +42,6 @@ private:
 	void nameSubmitDone(const MTPauth_Authorization &result);
 	bool nameSubmitFail(const RPCError &error);
 
-	void stopCheck();
-
 	object_ptr<Ui::UserpicButton> _photo;
 	object_ptr<Ui::InputField> _first;
 	object_ptr<Ui::InputField> _last;
@@ -59,7 +51,6 @@ private:
 	bool _invertOrder = false;
 
 	bool _termsAccepted = false;
-	object_ptr<QTimer> _checkRequest;
 
 };
 

From e6c86b19db3b0367f3ca22f15c1d90d08f284caf Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 27 Nov 2019 12:45:23 +0300
Subject: [PATCH 61/91] Use app config value for QR login.

---
 Telegram/Resources/langs/lang.strings         |  1 +
 .../view/media/history_view_sticker.cpp       |  5 +-
 Telegram/SourceFiles/intro/intro.style        |  1 +
 .../intro/{introcode.cpp => intro_code.cpp}   |  8 +--
 .../intro/{introcode.h => intro_code.h}       |  2 +-
 ...opwdcheck.cpp => intro_password_check.cpp} | 54 ++++++++---------
 ...intropwdcheck.h => intro_password_check.h} |  4 +-
 .../intro/{introphone.cpp => intro_phone.cpp} | 41 +++++++++++--
 .../intro/{introphone.h => intro_phone.h}     |  1 +
 Telegram/SourceFiles/intro/intro_qr.cpp       |  2 +-
 .../{introsignup.cpp => intro_signup.cpp}     |  4 +-
 .../intro/{introsignup.h => intro_signup.h}   |  0
 .../intro/{introstart.cpp => intro_start.cpp} | 13 +++-
 .../intro/{introstart.h => intro_start.h}     |  0
 Telegram/SourceFiles/intro/intro_step.cpp     |  2 +-
 .../{introwidget.cpp => intro_widget.cpp}     | 14 ++---
 .../intro/{introwidget.h => intro_widget.h}   |  0
 Telegram/SourceFiles/main/main_account.cpp    |  2 +
 Telegram/SourceFiles/main/main_account.h      |  7 +++
 Telegram/SourceFiles/main/main_app_config.cpp | 59 +++++++++++++++----
 Telegram/SourceFiles/main/main_app_config.h   | 29 +++++++--
 Telegram/SourceFiles/main/main_session.cpp    |  2 -
 Telegram/SourceFiles/main/main_session.h      |  5 --
 Telegram/SourceFiles/mainwindow.cpp           |  2 +-
 Telegram/gyp/telegram/sources.txt             | 24 ++++----
 25 files changed, 191 insertions(+), 91 deletions(-)
 rename Telegram/SourceFiles/intro/{introcode.cpp => intro_code.cpp} (98%)
 rename Telegram/SourceFiles/intro/{introcode.h => intro_code.h} (98%)
 rename Telegram/SourceFiles/intro/{intropwdcheck.cpp => intro_password_check.cpp} (86%)
 rename Telegram/SourceFiles/intro/{intropwdcheck.h => intro_password_check.h} (96%)
 rename Telegram/SourceFiles/intro/{introphone.cpp => intro_phone.cpp} (85%)
 rename Telegram/SourceFiles/intro/{introphone.h => intro_phone.h} (98%)
 rename Telegram/SourceFiles/intro/{introsignup.cpp => intro_signup.cpp} (98%)
 rename Telegram/SourceFiles/intro/{introsignup.h => intro_signup.h} (100%)
 rename Telegram/SourceFiles/intro/{introstart.cpp => intro_start.cpp} (76%)
 rename Telegram/SourceFiles/intro/{introstart.h => intro_start.h} (100%)
 rename Telegram/SourceFiles/intro/{introwidget.cpp => intro_widget.cpp} (98%)
 rename Telegram/SourceFiles/intro/{introwidget.h => intro_widget.h} (100%)

diff --git a/Telegram/Resources/langs/lang.strings b/Telegram/Resources/langs/lang.strings
index 58094bfa5..a6cb33086 100644
--- a/Telegram/Resources/langs/lang.strings
+++ b/Telegram/Resources/langs/lang.strings
@@ -186,6 +186,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 "lng_phone_title" = "Your Phone Number";
 "lng_phone_desc" = "Please confirm your country code and\nenter your mobile phone number.";
+"lng_phone_to_qr" = "Quick log in using QR code";
 "lng_country_code" = "Country Code";
 "lng_bad_country_code" = "Invalid Country Code";
 "lng_country_ph" = "Search";
diff --git a/Telegram/SourceFiles/history/view/media/history_view_sticker.cpp b/Telegram/SourceFiles/history/view/media/history_view_sticker.cpp
index 195b13915..717a0bf78 100644
--- a/Telegram/SourceFiles/history/view/media/history_view_sticker.cpp
+++ b/Telegram/SourceFiles/history/view/media/history_view_sticker.cpp
@@ -18,6 +18,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/image/image.h"
 #include "ui/emoji_config.h"
 #include "main/main_session.h"
+#include "main/main_account.h"
 #include "main/main_app_config.h"
 #include "mainwindow.h" // App::wnd()->sessionController.
 #include "window/window_session_controller.h" // isGifPausedAtLeastFor.
@@ -31,7 +32,9 @@ namespace HistoryView {
 namespace {
 
 double GetEmojiStickerZoom(not_null<Main::Session*> session) {
-	return session->appConfig().get<double>("emojies_animated_zoom", 0.625);
+	return session->account().appConfig().get<double>(
+		"emojies_animated_zoom",
+		0.625);
 }
 
 } // namespace
diff --git a/Telegram/SourceFiles/intro/intro.style b/Telegram/SourceFiles/intro/intro.style
index 26426f40d..ea76c95d5 100644
--- a/Telegram/SourceFiles/intro/intro.style
+++ b/Telegram/SourceFiles/intro/intro.style
@@ -107,6 +107,7 @@ introPhone: InputField(introCountry) {
 	textMargins: margins(12px, 27px, 12px, 6px);
 	width: 225px;
 }
+introQrLoginLinkTop: 368px;
 introCode: introCountry;
 introName: introCountry;
 introPassword: introCountry;
diff --git a/Telegram/SourceFiles/intro/introcode.cpp b/Telegram/SourceFiles/intro/intro_code.cpp
similarity index 98%
rename from Telegram/SourceFiles/intro/introcode.cpp
rename to Telegram/SourceFiles/intro/intro_code.cpp
index 14d3ae07c..1f2fbca91 100644
--- a/Telegram/SourceFiles/intro/introcode.cpp
+++ b/Telegram/SourceFiles/intro/intro_code.cpp
@@ -5,11 +5,11 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "intro/introcode.h"
+#include "intro/intro_code.h"
 
 #include "lang/lang_keys.h"
-#include "intro/introsignup.h"
-#include "intro/intropwdcheck.h"
+#include "intro/intro_signup.h"
+#include "intro/intro_password_check.h"
 #include "core/update_checker.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
@@ -355,7 +355,7 @@ void CodeWidget::gotPassword(const MTPaccount_Password &result) {
 	getData()->hasRecovery = d.is_has_recovery();
 	getData()->pwdHint = qs(d.vhint().value_or_empty());
 	getData()->pwdNotEmptyPassport = d.is_has_secure_values();
-	goReplace<PwdCheckWidget>();
+	goReplace<PasswordCheckWidget>();
 }
 
 void CodeWidget::submit() {
diff --git a/Telegram/SourceFiles/intro/introcode.h b/Telegram/SourceFiles/intro/intro_code.h
similarity index 98%
rename from Telegram/SourceFiles/intro/introcode.h
rename to Telegram/SourceFiles/intro/intro_code.h
index ddc72cdf1..719d8e091 100644
--- a/Telegram/SourceFiles/intro/introcode.h
+++ b/Telegram/SourceFiles/intro/intro_code.h
@@ -8,8 +8,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "intro/intro_step.h"
+#include "intro/intro_widget.h"
 #include "ui/widgets/input_fields.h"
-#include "intro/introwidget.h"
 #include "base/timer.h"
 
 namespace Ui {
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.cpp b/Telegram/SourceFiles/intro/intro_password_check.cpp
similarity index 86%
rename from Telegram/SourceFiles/intro/intropwdcheck.cpp
rename to Telegram/SourceFiles/intro/intro_password_check.cpp
index fe496fa31..eef08e616 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.cpp
+++ b/Telegram/SourceFiles/intro/intro_password_check.cpp
@@ -5,14 +5,14 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "intro/intropwdcheck.h"
+#include "intro/intro_password_check.h"
 
-#include "intro/introwidget.h"
+#include "intro/intro_widget.h"
 #include "core/file_utilities.h"
 #include "core/core_cloud_password.h"
 #include "boxes/confirm_box.h"
 #include "lang/lang_keys.h"
-#include "intro/introsignup.h"
+#include "intro/intro_signup.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/input_fields.h"
 #include "ui/widgets/labels.h"
@@ -24,7 +24,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace Intro {
 namespace details {
 
-PwdCheckWidget::PwdCheckWidget(
+PasswordCheckWidget::PasswordCheckWidget(
 	QWidget *parent,
 	not_null<Main::Account*> account,
 	not_null<Data*> data)
@@ -63,7 +63,7 @@ PwdCheckWidget::PwdCheckWidget(
 	setMouseTracking(true);
 }
 
-void PwdCheckWidget::refreshLang() {
+void PasswordCheckWidget::refreshLang() {
 	if (_toRecover) {
 		_toRecover->setText(tr::lng_signin_recover(tr::now));
 	}
@@ -78,16 +78,16 @@ void PwdCheckWidget::refreshLang() {
 	updateControlsGeometry();
 }
 
-int PwdCheckWidget::errorTop() const {
+int PasswordCheckWidget::errorTop() const {
 	return contentTop() + st::introErrorBelowLinkTop;
 }
 
-void PwdCheckWidget::resizeEvent(QResizeEvent *e) {
+void PasswordCheckWidget::resizeEvent(QResizeEvent *e) {
 	Step::resizeEvent(e);
 	updateControlsGeometry();
 }
 
-void PwdCheckWidget::updateControlsGeometry() {
+void PasswordCheckWidget::updateControlsGeometry() {
 	_pwdField->moveToLeft(contentLeft(), contentTop() + st::introPasswordTop);
 	_pwdHint->moveToLeft(contentLeft() + st::buttonRadius, contentTop() + st::introPasswordHintTop);
 	_codeField->moveToLeft(contentLeft(), contentTop() + st::introStepFieldTop);
@@ -96,7 +96,7 @@ void PwdCheckWidget::updateControlsGeometry() {
 	_toPassword->moveToLeft(contentLeft() + st::buttonRadius, linkTop);
 }
 
-void PwdCheckWidget::setInnerFocus() {
+void PasswordCheckWidget::setInnerFocus() {
 	if (_pwdField->isHidden()) {
 		_codeField->setFocusFast();
 	} else {
@@ -104,7 +104,7 @@ void PwdCheckWidget::setInnerFocus() {
 	}
 }
 
-void PwdCheckWidget::activate() {
+void PasswordCheckWidget::activate() {
 	if (_pwdField->isHidden() && _codeField->isHidden()) {
 		Step::activate();
 		_pwdField->show();
@@ -114,11 +114,11 @@ void PwdCheckWidget::activate() {
 	setInnerFocus();
 }
 
-void PwdCheckWidget::cancelled() {
+void PasswordCheckWidget::cancelled() {
 	_api.request(base::take(_sentRequest)).cancel();
 }
 
-void PwdCheckWidget::pwdSubmitDone(bool recover, const MTPauth_Authorization &result) {
+void PasswordCheckWidget::pwdSubmitDone(bool recover, const MTPauth_Authorization &result) {
 	_sentRequest = 0;
 	if (recover) {
 		cSetPasswordRecovered(true);
@@ -131,7 +131,7 @@ void PwdCheckWidget::pwdSubmitDone(bool recover, const MTPauth_Authorization &re
 	finish(d.vuser());
 }
 
-void PwdCheckWidget::pwdSubmitFail(const RPCError &error) {
+void PasswordCheckWidget::pwdSubmitFail(const RPCError &error) {
 	if (MTP::isFloodError(error)) {
 		_sentRequest = 0;
 		showError(tr::lng_flood_error());
@@ -161,7 +161,7 @@ void PwdCheckWidget::pwdSubmitFail(const RPCError &error) {
 	}
 }
 
-void PwdCheckWidget::handleSrpIdInvalid() {
+void PasswordCheckWidget::handleSrpIdInvalid() {
 	const auto now = crl::now();
 	if (_lastSrpIdInvalidTime > 0
 		&& now - _lastSrpIdInvalidTime < Core::kHandleSrpIdInvalidTimeout) {
@@ -173,7 +173,7 @@ void PwdCheckWidget::handleSrpIdInvalid() {
 	}
 }
 
-void PwdCheckWidget::checkPasswordHash() {
+void PasswordCheckWidget::checkPasswordHash() {
 	if (_request.id) {
 		passwordChecked();
 	} else {
@@ -181,7 +181,7 @@ void PwdCheckWidget::checkPasswordHash() {
 	}
 }
 
-void PwdCheckWidget::requestPasswordData() {
+void PasswordCheckWidget::requestPasswordData() {
 	_api.request(base::take(_sentRequest)).cancel();
 	_sentRequest = _api.request(
 		MTPaccount_GetPassword()
@@ -194,7 +194,7 @@ void PwdCheckWidget::requestPasswordData() {
 	}).send();
 }
 
-void PwdCheckWidget::passwordChecked() {
+void PasswordCheckWidget::passwordChecked() {
 	if (!_request || !_request.id) {
 		return serverError();
 	}
@@ -214,11 +214,11 @@ void PwdCheckWidget::passwordChecked() {
 	}).send();
 }
 
-void PwdCheckWidget::serverError() {
+void PasswordCheckWidget::serverError() {
 	showError(rpl::single(Lang::Hard::ServerError()));
 }
 
-void PwdCheckWidget::codeSubmitFail(const RPCError &error) {
+void PasswordCheckWidget::codeSubmitFail(const RPCError &error) {
 	if (MTP::isFloodError(error)) {
 		showError(tr::lng_flood_error());
 		_codeField->showError();
@@ -249,12 +249,12 @@ void PwdCheckWidget::codeSubmitFail(const RPCError &error) {
 	}
 }
 
-void PwdCheckWidget::recoverStarted(const MTPauth_PasswordRecovery &result) {
+void PasswordCheckWidget::recoverStarted(const MTPauth_PasswordRecovery &result) {
 	_emailPattern = qs(result.c_auth_passwordRecovery().vemail_pattern());
 	updateDescriptionText();
 }
 
-void PwdCheckWidget::recoverStartFail(const RPCError &error) {
+void PasswordCheckWidget::recoverStartFail(const RPCError &error) {
 	_pwdField->show();
 	_pwdHint->show();
 	_codeField->hide();
@@ -264,7 +264,7 @@ void PwdCheckWidget::recoverStartFail(const RPCError &error) {
 	hideError();
 }
 
-void PwdCheckWidget::toRecover() {
+void PasswordCheckWidget::toRecover() {
 	if (_hasRecovery) {
 		if (_sentRequest) {
 			_api.request(base::take(_sentRequest)).cancel();
@@ -294,13 +294,13 @@ void PwdCheckWidget::toRecover() {
 	}
 }
 
-void PwdCheckWidget::toPassword() {
+void PasswordCheckWidget::toPassword() {
 	Ui::show(Box<InformBox>(
 		tr::lng_signin_cant_email_forgot(tr::now),
 		[=] { showReset(); }));
 }
 
-void PwdCheckWidget::showReset() {
+void PasswordCheckWidget::showReset() {
 	if (_sentRequest) {
 		_api.request(base::take(_sentRequest)).cancel();
 	}
@@ -316,7 +316,7 @@ void PwdCheckWidget::showReset() {
 	update();
 }
 
-void PwdCheckWidget::updateDescriptionText() {
+void PasswordCheckWidget::updateDescriptionText() {
 	auto pwdHidden = _pwdField->isHidden();
 	auto emailPattern = _emailPattern;
 	setDescriptionText(pwdHidden
@@ -324,7 +324,7 @@ void PwdCheckWidget::updateDescriptionText() {
 		: tr::lng_signin_desc());
 }
 
-void PwdCheckWidget::submit() {
+void PasswordCheckWidget::submit() {
 	if (_sentRequest) {
 		return;
 	}
@@ -370,7 +370,7 @@ void PwdCheckWidget::submit() {
 	}
 }
 
-rpl::producer<QString> PwdCheckWidget::nextButtonText() const {
+rpl::producer<QString> PasswordCheckWidget::nextButtonText() const {
 	return tr::lng_intro_submit();
 }
 
diff --git a/Telegram/SourceFiles/intro/intropwdcheck.h b/Telegram/SourceFiles/intro/intro_password_check.h
similarity index 96%
rename from Telegram/SourceFiles/intro/intropwdcheck.h
rename to Telegram/SourceFiles/intro/intro_password_check.h
index 7b4fac982..fb16aae74 100644
--- a/Telegram/SourceFiles/intro/intropwdcheck.h
+++ b/Telegram/SourceFiles/intro/intro_password_check.h
@@ -22,9 +22,9 @@ class LinkButton;
 namespace Intro {
 namespace details {
 
-class PwdCheckWidget final : public Step {
+class PasswordCheckWidget final : public Step {
 public:
-	PwdCheckWidget(
+	PasswordCheckWidget(
 		QWidget *parent,
 		not_null<Main::Account*> account,
 		not_null<Data*> data);
diff --git a/Telegram/SourceFiles/intro/introphone.cpp b/Telegram/SourceFiles/intro/intro_phone.cpp
similarity index 85%
rename from Telegram/SourceFiles/intro/introphone.cpp
rename to Telegram/SourceFiles/intro/intro_phone.cpp
index fcf1f2036..c7f70c521 100644
--- a/Telegram/SourceFiles/intro/introphone.cpp
+++ b/Telegram/SourceFiles/intro/intro_phone.cpp
@@ -5,16 +5,18 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "intro/introphone.h"
+#include "intro/intro_phone.h"
 
 #include "lang/lang_keys.h"
-#include "intro/introcode.h"
+#include "intro/intro_code.h"
+#include "intro/intro_qr.h"
 #include "styles/style_intro.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
 #include "ui/wrap/fade_wrap.h"
 #include "ui/special_fields.h"
 #include "main/main_account.h"
+#include "main/main_app_config.h"
 #include "boxes/confirm_phone_box.h"
 #include "boxes/confirm_box.h"
 #include "core/application.h"
@@ -54,6 +56,7 @@ PhoneWidget::PhoneWidget(
 	setDescriptionText(tr::lng_phone_desc());
 	subscribe(getData()->updated, [=] { countryChanged(); });
 	setErrorCentered(true);
+	setupQrLogin();
 
 	if (!_country->onChooseCountry(getData()->country)) {
 		_country->onChooseCountry(qsl("US"));
@@ -61,6 +64,36 @@ PhoneWidget::PhoneWidget(
 	_changed = false;
 }
 
+void PhoneWidget::setupQrLogin() {
+	rpl::single(
+		rpl::empty_value()
+	) | rpl::then(
+		account().appConfig().refreshed()
+	) | rpl::map([=] {
+		return account().appConfig().get<QString>(
+			"qr_login_code",
+			"disabled");
+	}) | rpl::filter([](const QString &value) {
+		return (value != "disabled");
+	}) | rpl::take(1) | rpl::start_with_next([=] {
+		const auto qrLogin = Ui::CreateChild<Ui::LinkButton>(
+			this,
+			tr::lng_phone_to_qr(tr::now));
+		qrLogin->show();
+
+		rpl::combine(
+			sizeValue(),
+			qrLogin->widthValue()
+		) | rpl::start_with_next([=](QSize size, int qrLoginWidth) {
+			qrLogin->moveToLeft(
+				(size.width() - qrLoginWidth) / 2,
+				contentTop() + st::introQrLoginLinkTop);
+		}, qrLogin->lifetime());
+
+		qrLogin->setClickedCallback([=] { goReplace<QrWidget>(); });
+	}, lifetime());
+}
+
 void PhoneWidget::resizeEvent(QResizeEvent *e) {
 	Step::resizeEvent(e);
 	_country->moveToLeft(contentLeft(), contentTop() + st::introStepFieldTop);
@@ -200,9 +233,7 @@ void PhoneWidget::setInnerFocus() {
 
 void PhoneWidget::activate() {
 	Step::activate();
-	_country->show();
-	_phone->show();
-	_code->show();
+	showChildren();
 	setInnerFocus();
 }
 
diff --git a/Telegram/SourceFiles/intro/introphone.h b/Telegram/SourceFiles/intro/intro_phone.h
similarity index 98%
rename from Telegram/SourceFiles/intro/introphone.h
rename to Telegram/SourceFiles/intro/intro_phone.h
index cb34386c8..29e6699fc 100644
--- a/Telegram/SourceFiles/intro/introphone.h
+++ b/Telegram/SourceFiles/intro/intro_phone.h
@@ -44,6 +44,7 @@ protected:
 	void resizeEvent(QResizeEvent *e) override;
 
 private:
+	void setupQrLogin();
 	void phoneChanged();
 	void checkRequest();
 	void countryChanged();
diff --git a/Telegram/SourceFiles/intro/intro_qr.cpp b/Telegram/SourceFiles/intro/intro_qr.cpp
index 92203e316..079297c15 100644
--- a/Telegram/SourceFiles/intro/intro_qr.cpp
+++ b/Telegram/SourceFiles/intro/intro_qr.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "intro/intro_qr.h"
 
-#include "intro/introphone.h"
+#include "intro/intro_phone.h"
 #include "lang/lang_keys.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
diff --git a/Telegram/SourceFiles/intro/introsignup.cpp b/Telegram/SourceFiles/intro/intro_signup.cpp
similarity index 98%
rename from Telegram/SourceFiles/intro/introsignup.cpp
rename to Telegram/SourceFiles/intro/intro_signup.cpp
index 9e0c02749..e297dec66 100644
--- a/Telegram/SourceFiles/intro/introsignup.cpp
+++ b/Telegram/SourceFiles/intro/intro_signup.cpp
@@ -5,9 +5,9 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "intro/introsignup.h"
+#include "intro/intro_signup.h"
 
-#include "intro/introwidget.h"
+#include "intro/intro_widget.h"
 #include "core/file_utilities.h"
 #include "boxes/photo_crop_box.h"
 #include "boxes/confirm_box.h"
diff --git a/Telegram/SourceFiles/intro/introsignup.h b/Telegram/SourceFiles/intro/intro_signup.h
similarity index 100%
rename from Telegram/SourceFiles/intro/introsignup.h
rename to Telegram/SourceFiles/intro/intro_signup.h
diff --git a/Telegram/SourceFiles/intro/introstart.cpp b/Telegram/SourceFiles/intro/intro_start.cpp
similarity index 76%
rename from Telegram/SourceFiles/intro/introstart.cpp
rename to Telegram/SourceFiles/intro/intro_start.cpp
index b8b3cfc57..53ed00685 100644
--- a/Telegram/SourceFiles/intro/introstart.cpp
+++ b/Telegram/SourceFiles/intro/intro_start.cpp
@@ -5,13 +5,15 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "intro/introstart.h"
+#include "intro/intro_start.h"
 
 #include "lang/lang_keys.h"
 #include "intro/intro_qr.h"
+#include "intro/intro_phone.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/labels.h"
 #include "main/main_account.h"
+#include "main/main_app_config.h"
 
 namespace Intro {
 namespace details {
@@ -29,7 +31,14 @@ StartWidget::StartWidget(
 
 void StartWidget::submit() {
 	account().destroyStaleAuthorizationKeys();
-	goNext<QrWidget>();
+	const auto qrLogin = account().appConfig().get<QString>(
+		"qr_login_code",
+		"disabled");
+	if (qrLogin == "primary") {
+		goNext<QrWidget>();
+	} else {
+		goNext<PhoneWidget>();
+	}
 }
 
 rpl::producer<QString> StartWidget::nextButtonText() const {
diff --git a/Telegram/SourceFiles/intro/introstart.h b/Telegram/SourceFiles/intro/intro_start.h
similarity index 100%
rename from Telegram/SourceFiles/intro/introstart.h
rename to Telegram/SourceFiles/intro/intro_start.h
diff --git a/Telegram/SourceFiles/intro/intro_step.cpp b/Telegram/SourceFiles/intro/intro_step.cpp
index 0a5f3e2d3..151951b49 100644
--- a/Telegram/SourceFiles/intro/intro_step.cpp
+++ b/Telegram/SourceFiles/intro/intro_step.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "intro/intro_step.h"
 
-#include "intro/introwidget.h"
+#include "intro/intro_widget.h"
 #include "storage/localstorage.h"
 #include "lang/lang_keys.h"
 #include "lang/lang_cloud_manager.h"
diff --git a/Telegram/SourceFiles/intro/introwidget.cpp b/Telegram/SourceFiles/intro/intro_widget.cpp
similarity index 98%
rename from Telegram/SourceFiles/intro/introwidget.cpp
rename to Telegram/SourceFiles/intro/intro_widget.cpp
index f6ed2d7e3..078c43f3e 100644
--- a/Telegram/SourceFiles/intro/introwidget.cpp
+++ b/Telegram/SourceFiles/intro/intro_widget.cpp
@@ -5,13 +5,13 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "intro/introwidget.h"
+#include "intro/intro_widget.h"
 
-#include "intro/introstart.h"
-#include "intro/introphone.h"
-#include "intro/introcode.h"
-#include "intro/introsignup.h"
-#include "intro/intropwdcheck.h"
+#include "intro/intro_start.h"
+#include "intro/intro_phone.h"
+#include "intro/intro_code.h"
+#include "intro/intro_signup.h"
+#include "intro/intro_password_check.h"
 #include "lang/lang_keys.h"
 #include "lang/lang_cloud_manager.h"
 #include "storage/localstorage.h"
@@ -82,7 +82,7 @@ Widget::Widget(QWidget *parent, not_null<Main::Account*> account)
 	_settings->entity()->setClickedCallback([] { App::wnd()->showSettings(); });
 
 	getNearestDC();
-	
+
 	if (_changeLanguage) {
 		_changeLanguage->finishAnimating();
 	}
diff --git a/Telegram/SourceFiles/intro/introwidget.h b/Telegram/SourceFiles/intro/intro_widget.h
similarity index 100%
rename from Telegram/SourceFiles/intro/introwidget.h
rename to Telegram/SourceFiles/intro/intro_widget.h
diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index fcc3a8ad6..55ebf9c47 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -18,6 +18,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "media/audio/media_audio.h"
 #include "mainwidget.h"
 #include "observer_peer.h"
+#include "main/main_app_config.h"
 #include "main/main_session.h"
 #include "facades.h"
 
@@ -26,6 +27,7 @@ namespace Main {
 Account::Account(const QString &dataName) {
 	watchProxyChanges();
 	watchSessionChanges();
+	_appConfig = std::make_unique<AppConfig>(this);
 }
 
 Account::~Account() = default;
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 5e4fc1238..844f47845 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -15,6 +15,7 @@ namespace Main {
 
 class Session;
 class Settings;
+class AppConfig;
 
 class Account final : public base::has_weak_ptr {
 public:
@@ -35,6 +36,10 @@ public:
 	void logOut();
 	void forcedLogOut();
 
+	[[nodiscard]] AppConfig &appConfig() {
+		return *_appConfig;
+	}
+
 	[[nodiscard]] bool sessionExists() const;
 	[[nodiscard]] Session &session();
 	[[nodiscard]] const Session &session() const;
@@ -92,6 +97,8 @@ private:
 	rpl::event_stream<> _mtpNewSessionCreated;
 	rpl::event_stream<> _configUpdates;
 
+	std::unique_ptr<AppConfig> _appConfig;
+
 	std::unique_ptr<Session> _session;
 	rpl::variable<Session*> _sessionValue;
 
diff --git a/Telegram/SourceFiles/main/main_app_config.cpp b/Telegram/SourceFiles/main/main_app_config.cpp
index 2f6d76bb1..bf8820725 100644
--- a/Telegram/SourceFiles/main/main_app_config.cpp
+++ b/Telegram/SourceFiles/main/main_app_config.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "main/main_app_config.h"
 
-#include "main/main_session.h"
+#include "main/main_account.h"
 #include "base/call_delayed.h"
 #include "apiwrap.h"
 
@@ -18,15 +18,25 @@ constexpr auto kRefreshTimeout = 3600 * crl::time(1000);
 
 } // namespace
 
-AppConfig::AppConfig(not_null<Session*> session) : _session(session) {
+AppConfig::AppConfig(not_null<Account*> account) : _account(account) {
+	account->mtpValue(
+	) | rpl::start_with_next([=](MTP::Instance *instance) {
+		if (instance) {
+			_api.emplace(instance);
+			refresh();
+		} else {
+			_api.reset();
+			_requestId = 0;
+		}
+	}, _lifetime);
 	refresh();
 }
 
 void AppConfig::refresh() {
-	if (_requestId) {
+	if (_requestId || !_api) {
 		return;
 	}
-	_requestId = _session->api().request(MTPhelp_GetAppConfig(
+	_requestId = _api->request(MTPhelp_GetAppConfig(
 	)).done([=](const MTPJSONValue &result) {
 		_requestId = 0;
 		refreshDelayed();
@@ -37,6 +47,7 @@ void AppConfig::refresh() {
 				});
 			}
 		}
+		_refreshed.fire({});
 	}).fail([=](const RPCError &error) {
 		_requestId = 0;
 		refreshDelayed();
@@ -44,20 +55,42 @@ void AppConfig::refresh() {
 }
 
 void AppConfig::refreshDelayed() {
-	base::call_delayed(kRefreshTimeout, _session, [=] {
+	base::call_delayed(kRefreshTimeout, _account, [=] {
 		refresh();
 	});
 }
 
-double AppConfig::getDouble(const QString &key, double fallback) const {
+rpl::producer<> AppConfig::refreshed() const {
+	return _refreshed.events();
+}
+
+template <typename Extractor>
+auto AppConfig::getValue(const QString &key, Extractor &&extractor) const {
 	const auto i = _data.find(key);
-	if (i == end(_data)) {
-		return fallback;
-	}
-	return i->second.match([&](const MTPDjsonNumber &data) {
-		return data.vvalue().v;
-	}, [&](const auto &data) {
-		return fallback;
+	return extractor((i != end(_data))
+		? i->second
+		: MTPJSONValue(MTP_jsonNull()));
+}
+
+double AppConfig::getDouble(const QString &key, double fallback) const {
+	return getValue(key, [&](const MTPJSONValue &value) {
+		return value.match([&](const MTPDjsonNumber &data) {
+			return data.vvalue().v;
+		}, [&](const auto &data) {
+			return fallback;
+		});
+	});
+}
+
+QString AppConfig::getString(
+		const QString &key,
+		const QString &fallback) const {
+	return getValue(key, [&](const MTPJSONValue &value) {
+		return value.match([&](const MTPDjsonString &data) {
+			return qs(data.vvalue());
+		}, [&](const auto &data) {
+			return fallback;
+		});
 	});
 }
 
diff --git a/Telegram/SourceFiles/main/main_app_config.h b/Telegram/SourceFiles/main/main_app_config.h
index 25afb4e77..3eb8b4315 100644
--- a/Telegram/SourceFiles/main/main_app_config.h
+++ b/Telegram/SourceFiles/main/main_app_config.h
@@ -7,30 +7,49 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "mtproto/sender.h"
+
 namespace Main {
 
-class Session;
+class Account;
 
 class AppConfig final {
 public:
-	explicit AppConfig(not_null<Session*> session);
+	explicit AppConfig(not_null<Account*> account);
 
 	template <typename Type>
-	Type get(const QString &key, Type fallback) const {
+	[[nodiscard]] Type get(const QString &key, Type fallback) const {
 		if constexpr (std::is_same_v<Type, double>) {
 			return getDouble(key, fallback);
+		} else if constexpr (std::is_same_v<Type, QString>) {
+			return getString(key, fallback);
 		}
 	}
 
+	[[nodiscard]] rpl::producer<> refreshed() const;
+
 private:
 	void refresh();
 	void refreshDelayed();
 
-	double getDouble(const QString &key, double fallback) const;
+	template <typename Extractor>
+	[[nodiscard]] auto getValue(
+		const QString &key,
+		Extractor &&extractor) const;
 
-	not_null<Session*> _session;
+	[[nodiscard]] double getDouble(
+		const QString &key,
+		double fallback) const;
+	[[nodiscard]] QString getString(
+		const QString &key,
+		const QString &fallback) const;
+
+	const not_null<Account*> _account;
+	std::optional<MTP::Sender> _api;
 	mtpRequestId _requestId = 0;
 	base::flat_map<QString, MTPJSONValue> _data;
+	rpl::event_stream<> _refreshed;
+	rpl::lifetime _lifetime;
 
 };
 
diff --git a/Telegram/SourceFiles/main/main_session.cpp b/Telegram/SourceFiles/main/main_session.cpp
index fe93b0352..eceeaa826 100644
--- a/Telegram/SourceFiles/main/main_session.cpp
+++ b/Telegram/SourceFiles/main/main_session.cpp
@@ -11,7 +11,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/application.h"
 #include "core/changelogs.h"
 #include "main/main_account.h"
-#include "main/main_app_config.h"
 #include "chat_helpers/stickers_emoji_pack.h"
 #include "storage/file_download.h"
 #include "storage/file_upload.h"
@@ -44,7 +43,6 @@ Session::Session(
 , _saveSettingsTimer([=] { Local::writeUserSettings(); })
 , _autoLockTimer([=] { checkAutoLock(); })
 , _api(std::make_unique<ApiWrap>(this))
-, _appConfig(std::make_unique<AppConfig>(this))
 , _calls(std::make_unique<Calls::Instance>(this))
 , _downloader(std::make_unique<Storage::Downloader>(_api.get()))
 , _uploader(std::make_unique<Storage::Uploader>(_api.get()))
diff --git a/Telegram/SourceFiles/main/main_session.h b/Telegram/SourceFiles/main/main_session.h
index 34231c0a2..ed12fcc94 100644
--- a/Telegram/SourceFiles/main/main_session.h
+++ b/Telegram/SourceFiles/main/main_session.h
@@ -55,7 +55,6 @@ class Changelogs;
 namespace Main {
 
 class Account;
-class AppConfig;
 
 class Session final
 	: public base::has_weak_ptr
@@ -93,9 +92,6 @@ public:
 	[[nodiscard]] Stickers::EmojiPack &emojiStickersPack() {
 		return *_emojiStickersPack;
 	}
-	[[nodiscard]] AppConfig &appConfig() {
-		return *_appConfig;
-	}
 
 	[[nodiscard]] base::Observable<void> &downloaderTaskFinished();
 
@@ -148,7 +144,6 @@ private:
 	base::Timer _autoLockTimer;
 
 	const std::unique_ptr<ApiWrap> _api;
-	const std::unique_ptr<AppConfig> _appConfig;
 	const std::unique_ptr<Calls::Instance> _calls;
 	const std::unique_ptr<Storage::Downloader> _downloader;
 	const std::unique_ptr<Storage::Uploader> _uploader;
diff --git a/Telegram/SourceFiles/mainwindow.cpp b/Telegram/SourceFiles/mainwindow.cpp
index 24e641e7f..ccbd607f5 100644
--- a/Telegram/SourceFiles/mainwindow.cpp
+++ b/Telegram/SourceFiles/mainwindow.cpp
@@ -25,7 +25,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/sandbox.h"
 #include "core/application.h"
 #include "main/main_session.h"
-#include "intro/introwidget.h"
+#include "intro/intro_widget.h"
 #include "main/main_account.h" // Account::sessionValue.
 #include "mainwidget.h"
 #include "boxes/confirm_box.h"
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index 37b643429..c4d81714e 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -432,22 +432,22 @@
 <(src_loc)/inline_bots/inline_bot_send_data.h
 <(src_loc)/inline_bots/inline_results_widget.cpp
 <(src_loc)/inline_bots/inline_results_widget.h
-<(src_loc)/intro/introwidget.cpp
-<(src_loc)/intro/introwidget.h
-<(src_loc)/intro/introcode.cpp
-<(src_loc)/intro/introcode.h
-<(src_loc)/intro/introphone.cpp
-<(src_loc)/intro/introphone.h
-<(src_loc)/intro/intropwdcheck.cpp
-<(src_loc)/intro/intropwdcheck.h
-<(src_loc)/intro/introsignup.cpp
-<(src_loc)/intro/introsignup.h
-<(src_loc)/intro/introstart.cpp
-<(src_loc)/intro/introstart.h
+<(src_loc)/intro/intro_code.cpp
+<(src_loc)/intro/intro_code.h
+<(src_loc)/intro/intro_password_check.cpp
+<(src_loc)/intro/intro_password_check.h
+<(src_loc)/intro/intro_phone.cpp
+<(src_loc)/intro/intro_phone.h
 <(src_loc)/intro/intro_qr.cpp
 <(src_loc)/intro/intro_qr.h
+<(src_loc)/intro/intro_signup.cpp
+<(src_loc)/intro/intro_signup.h
+<(src_loc)/intro/intro_start.cpp
+<(src_loc)/intro/intro_start.h
 <(src_loc)/intro/intro_step.cpp
 <(src_loc)/intro/intro_step.h
+<(src_loc)/intro/intro_widget.cpp
+<(src_loc)/intro/intro_widget.h
 <(src_loc)/lang/lang_cloud_manager.cpp
 <(src_loc)/lang/lang_cloud_manager.h
 <(src_loc)/lang/lang_file_parser.cpp

From 06f5f7f7d93ab0de9df4bb67237055135fd1dcf0 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 27 Nov 2019 13:41:17 +0300
Subject: [PATCH 62/91] Don't always restart connection on config change.

---
 Telegram/SourceFiles/core/application.cpp     | 20 +++++++++------
 Telegram/SourceFiles/mtproto/connection.cpp   | 24 +++++++++++++-----
 Telegram/SourceFiles/mtproto/connection.h     |  3 ++-
 Telegram/SourceFiles/mtproto/dc_options.cpp   | 25 +++++++++++--------
 Telegram/SourceFiles/mtproto/dc_options.h     | 11 +++-----
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  2 --
 Telegram/SourceFiles/mtproto/mtp_instance.h   |  1 -
 7 files changed, 50 insertions(+), 36 deletions(-)

diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index 048a6794e..04a167751 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -399,14 +399,18 @@ void Application::badMtprotoConfigurationError() {
 
 void Application::startLocalStorage() {
 	Local::start();
-	subscribe(_dcOptions->changed(), [this](const MTP::DcOptions::Ids &ids) {
-		Local::writeSettings();
-		if (const auto instance = activeAccount().mtp()) {
-			for (const auto id : ids) {
-				instance->restart(id);
-			}
-		}
-	});
+
+	const auto writing = _lifetime.make_state<bool>(false);
+	_dcOptions->changed(
+	) | rpl::filter([=] {
+		return !*writing;
+	}) | rpl::start_with_next([=] {
+		*writing = true;
+		Ui::PostponeCall(this, [=] {
+			Local::writeSettings();
+		});
+	}, _lifetime);
+
 	_saveSettingsTimer.setCallback([=] { Local::writeSettings(); });
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 80f4e478e..8e35f8977 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -126,7 +126,9 @@ Connection::~Connection() {
 	}
 }
 
-void Connection::start(std::shared_ptr<SessionData> sessionData, ShiftedDcId shiftedDcId) {
+void Connection::start(
+		std::shared_ptr<SessionData> sessionData,
+		ShiftedDcId shiftedDcId) {
 	Expects(_thread == nullptr && _private == nullptr);
 
 	_thread = std::make_unique<QThread>();
@@ -137,6 +139,16 @@ void Connection::start(std::shared_ptr<SessionData> sessionData, ShiftedDcId shi
 		std::move(sessionData),
 		shiftedDcId);
 
+	_instance->dcOptions()->changed(
+	) | rpl::filter([=](DcId dcId) {
+		return (BareDcId(shiftedDcId) == dcId) && (_private != nullptr);
+	}) | rpl::start_with_next([=] {
+		const auto raw = _private;
+		InvokeQueued(raw, [=] {
+			raw->dcOptionsChanged();
+		});
+	}, _lifetime);
+
 	// will be deleted in the thread::finished signal
 	_private = newData.release();
 	_thread->start();
@@ -329,10 +341,6 @@ ConnectionPrivate::~ConnectionPrivate() {
 	Expects(_testConnections.empty());
 }
 
-void ConnectionPrivate::onConfigLoaded() {
-	connectToServer(true);
-}
-
 void ConnectionPrivate::onCDNConfigLoaded() {
 	restart();
 }
@@ -341,6 +349,11 @@ int32 ConnectionPrivate::getShiftedDcId() const {
 	return _shiftedDcId;
 }
 
+void ConnectionPrivate::dcOptionsChanged() {
+	_retryTimeout = 1;
+	connectToServer(true);
+}
+
 int32 ConnectionPrivate::getState() const {
 	QReadLocker lock(&_stateMutex);
 	int32 result = _state;
@@ -1004,7 +1017,6 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 			return restart();
 		}
 		DEBUG_LOG(("MTP Info: DC %1 options not found, waiting for config").arg(_shiftedDcId));
-		connect(_instance, SIGNAL(configLoaded()), this, SLOT(onConfigLoaded()), Qt::UniqueConnection);
 		InvokeQueued(_instance, [instance = _instance] {
 			instance->requestConfig();
 		});
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 2715bb640..fddd75bd7 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -58,6 +58,7 @@ private:
 	not_null<Instance*> _instance;
 	std::unique_ptr<QThread> _thread;
 	ConnectionPrivate *_private = nullptr;
+	rpl::lifetime _lifetime;
 
 };
 
@@ -76,6 +77,7 @@ public:
 	void stop();
 
 	int32 getShiftedDcId() const;
+	void dcOptionsChanged();
 
 	int32 getState() const;
 	QString transport() const;
@@ -90,7 +92,6 @@ public slots:
 
 	void updateAuthKey();
 
-	void onConfigLoaded();
 	void onCDNConfigLoaded();
 
 private:
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index 7e22e4c5b..cbac04e31 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -170,7 +170,7 @@ void DcOptions::processFromList(
 		ApplyOneOption(data, dcId, flags, ip, port, secret);
 	}
 
-	auto difference = [&] {
+	const auto difference = [&] {
 		WriteLocker lock(this);
 		auto result = CountOptionsDifference(_data, data);
 		if (!result.empty()) {
@@ -178,8 +178,8 @@ void DcOptions::processFromList(
 		}
 		return result;
 	}();
-	if (!difference.empty()) {
-		_changed.notify(std::move(difference));
+	for (const auto dcId : difference) {
+		_changed.fire_copy(dcId);
 	}
 }
 
@@ -232,9 +232,8 @@ void DcOptions::addFromOther(DcOptions &&options) {
 			}
 		}
 	}
-
-	if (!idsChanged.empty()) {
-		_changed.notify(std::move(idsChanged));
+	for (const auto dcId : idsChanged) {
+		_changed.fire_copy(dcId);
 	}
 }
 
@@ -280,10 +279,10 @@ bool DcOptions::ApplyOneOption(
 	return true;
 }
 
-auto DcOptions::CountOptionsDifference(
+std::vector<DcId> DcOptions::CountOptionsDifference(
 		const std::map<DcId, std::vector<Endpoint>> &a,
-		const std::map<DcId, std::vector<Endpoint>> &b) -> Ids {
-	auto result = Ids();
+		const std::map<DcId, std::vector<Endpoint>> &b) {
+	auto result = std::vector<DcId>();
 	const auto find = [](
 			const std::vector<Endpoint> &where,
 			const Endpoint &what) {
@@ -514,8 +513,12 @@ void DcOptions::constructFromSerialized(const QByteArray &serialized) {
 	}
 }
 
-DcOptions::Ids DcOptions::configEnumDcIds() const {
-	auto result = Ids();
+rpl::producer<DcId> DcOptions::changed() const {
+	return _changed.events();
+}
+
+std::vector<DcId> DcOptions::configEnumDcIds() const {
+	auto result = std::vector<DcId>();
 	{
 		ReadLocker lock(this);
 		result.reserve(_data.size());
diff --git a/Telegram/SourceFiles/mtproto/dc_options.h b/Telegram/SourceFiles/mtproto/dc_options.h
index 70b7a79dd..4c21e5567 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.h
+++ b/Telegram/SourceFiles/mtproto/dc_options.h
@@ -66,15 +66,12 @@ public:
 		const bytes::vector &secret);
 	QByteArray serialize() const;
 
-	using Ids = std::vector<DcId>;
-	base::Observable<Ids> &changed() const {
-		return _changed;
-	}
+	[[nodiscard]] rpl::producer<DcId> changed() const;
 	void setFromList(const MTPVector<MTPDcOption> &options);
 	void addFromList(const MTPVector<MTPDcOption> &options);
 	void addFromOther(DcOptions &&options);
 
-	Ids configEnumDcIds() const;
+	[[nodiscard]] std::vector<DcId> configEnumDcIds() const;
 
 	struct Variants {
 		enum Address {
@@ -119,7 +116,7 @@ private:
 		const std::string &ip,
 		int port,
 		const bytes::vector &secret);
-	static Ids CountOptionsDifference(
+	static std::vector<DcId> CountOptionsDifference(
 		const std::map<DcId, std::vector<Endpoint>> &a,
 		const std::map<DcId, std::vector<Endpoint>> &b);
 	static void FilterIfHasWithFlag(Variants &variants, Flag flag);
@@ -143,7 +140,7 @@ private:
 	std::map<DcId, std::map<uint64, internal::RSAPublicKey>> _cdnPublicKeys;
 	mutable QReadWriteLock _useThroughLockers;
 
-	mutable base::Observable<Ids> _changed;
+	rpl::event_stream<DcId> _changed;
 
 	// True when we have overriden options from a .tdesktop-endpoints file.
 	bool _immutable = false;
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 5bef40a88..3f4a91e63 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -860,8 +860,6 @@ void Instance::Private::configLoadDone(const MTPConfig &result) {
 	_configExpiresAt = crl::now()
 		+ (data.vexpires().v - base::unixtime::now()) * crl::time(1000);
 	requestConfigIfExpired();
-
-	emit _instance->configLoaded();
 }
 
 bool Instance::Private::configLoadFail(const RPCError &error) {
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 17e2f5889..f28f635cc 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -199,7 +199,6 @@ public:
 	}
 
 signals:
-	void configLoaded();
 	void cdnConfigLoaded();
 	void allKeysDestroyed();
 	void proxyDomainResolved(

From c742d7406cfa1daba8533f05c15bc5312ab9f195 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 27 Nov 2019 17:22:22 +0300
Subject: [PATCH 63/91] Make MTP::Session handle the connection thread.

---
 Telegram/SourceFiles/main/main_account.cpp    |  20 +-
 Telegram/SourceFiles/main/main_account.h      |   1 -
 Telegram/SourceFiles/mtproto/connection.cpp   | 296 ++++++------------
 Telegram/SourceFiles/mtproto/connection.h     |  70 +----
 Telegram/SourceFiles/mtproto/dc_options.cpp   |  42 ++-
 Telegram/SourceFiles/mtproto/dc_options.h     |   2 +
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  53 +---
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   9 +-
 Telegram/SourceFiles/mtproto/session.cpp      | 119 +++++--
 Telegram/SourceFiles/mtproto/session.h        |  32 +-
 10 files changed, 277 insertions(+), 367 deletions(-)

diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index 55ebf9c47..82030ea93 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -453,18 +453,14 @@ void Account::destroyMtpKeys(MTP::AuthKeysList &&keys) {
 		Core::App().dcOptions(),
 		MTP::Instance::Mode::KeysDestroyer,
 		std::move(destroyConfig));
-	QObject::connect(
-		_mtpForKeysDestroy.get(),
-		&MTP::Instance::allKeysDestroyed,
-		[=] { allKeysDestroyed(); });
-}
-
-void Account::allKeysDestroyed() {
-	LOG(("MTP Info: all keys scheduled for destroy are destroyed."));
-	crl::on_main(this, [=] {
-		_mtpForKeysDestroy = nullptr;
-		Local::writeMtpData();
-	});
+	_mtpForKeysDestroy->allKeysDestroyed(
+	) | rpl::start_with_next([=] {
+		LOG(("MTP Info: all keys scheduled for destroy are destroyed."));
+		crl::on_main(this, [=] {
+			_mtpForKeysDestroy = nullptr;
+			Local::writeMtpData();
+		});
+	}, _lifetime);
 }
 
 void Account::suggestMainDcId(MTP::DcId mainDcId) {
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 844f47845..374cad860 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -85,7 +85,6 @@ private:
 	void watchSessionChanges();
 
 	void destroyMtpKeys(MTP::AuthKeysList &&keys);
-	void allKeysDestroyed();
 	void resetAuthorizationKeys();
 
 	void loggedOut();
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 8e35f8977..b17f50b88 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -114,75 +114,46 @@ void WrapInvokeAfter(
 
 } // namespace
 
-Connection::Connection(not_null<Instance*> instance)
-: _instance(instance) {
+Connection::Connection(
+	not_null<Instance*> instance,
+	not_null<QThread*> thread,
+	std::shared_ptr<SessionData> data,
+	ShiftedDcId shiftedDcId)
+: QObject(nullptr)
+, _instance(instance)
+, _shiftedDcId(shiftedDcId)
+, _realDcType(_instance->dcOptions()->dcType(_shiftedDcId))
+, _currentDcType(_realDcType)
+, _state(DisconnectedState)
+, _retryTimer(thread, [=] { retryByTimer(); })
+, _oldConnectionTimer(thread, [=] { markConnectionOld(); })
+, _waitForConnectedTimer(thread, [=] { waitConnectedFailed(); })
+, _waitForReceivedTimer(thread, [=] { waitReceivedFailed(); })
+, _waitForBetterTimer(thread, [=] { waitBetterFailed(); })
+, _waitForReceived(kMinReceiveTimeout)
+, _waitForConnected(kMinConnectedTimeout)
+, _pingSender(thread, [=] { sendPingByTimer(); })
+, _checkSentRequestsTimer(thread, [=] { checkSentRequests(); })
+, _sessionData(std::move(data)) {
+	Expects(_shiftedDcId != 0);
+
+	moveToThread(thread);
+
+	connect(thread, &QThread::started, this, [=] {
+		_checkSentRequestsTimer.callEach(kCheckSentRequestsEach);
+		connectToServer();
+	});
 }
 
 Connection::~Connection() {
-	Expects(_private == nullptr);
+	releaseKeyCreationOnFail();
+	doDisconnect();
 
-	if (_thread) {
-		waitTillFinish();
-	}
+	Expects(!_connection);
+	Expects(_testConnections.empty());
 }
 
-void Connection::start(
-		std::shared_ptr<SessionData> sessionData,
-		ShiftedDcId shiftedDcId) {
-	Expects(_thread == nullptr && _private == nullptr);
-
-	_thread = std::make_unique<QThread>();
-	auto newData = std::make_unique<ConnectionPrivate>(
-		_instance,
-		_thread.get(),
-		this,
-		std::move(sessionData),
-		shiftedDcId);
-
-	_instance->dcOptions()->changed(
-	) | rpl::filter([=](DcId dcId) {
-		return (BareDcId(shiftedDcId) == dcId) && (_private != nullptr);
-	}) | rpl::start_with_next([=] {
-		const auto raw = _private;
-		InvokeQueued(raw, [=] {
-			raw->dcOptionsChanged();
-		});
-	}, _lifetime);
-
-	// will be deleted in the thread::finished signal
-	_private = newData.release();
-	_thread->start();
-}
-
-void Connection::kill() {
-	Expects(_private != nullptr && _thread != nullptr);
-
-	_private->stop();
-	_private = nullptr;
-	_thread->quit();
-}
-
-void Connection::waitTillFinish() {
-	Expects(_private == nullptr && _thread != nullptr);
-
-	DEBUG_LOG(("Waiting for connectionThread to finish"));
-	_thread->wait();
-	_thread.reset();
-}
-
-int32 Connection::state() const {
-	Expects(_private != nullptr && _thread != nullptr);
-
-	return _private->getState();
-}
-
-QString Connection::transport() const {
-	Expects(_private != nullptr && _thread != nullptr);
-
-	return _private->transport();
-}
-
-void ConnectionPrivate::appendTestConnection(
+void Connection::appendTestConnection(
 		DcOptions::Variants::Protocol protocol,
 		const QString &ip,
 		int port,
@@ -231,7 +202,7 @@ void ConnectionPrivate::appendTestConnection(
 	});
 }
 
-int16 ConnectionPrivate::getProtocolDcId() const {
+int16 Connection::getProtocolDcId() const {
 	const auto dcId = BareDcId(_shiftedDcId);
 	const auto simpleDcId = isTemporaryDcId(dcId)
 		? getRealIdFromTemporaryDcId(dcId)
@@ -244,7 +215,7 @@ int16 ConnectionPrivate::getProtocolDcId() const {
 		: testedDcId;
 }
 
-void ConnectionPrivate::checkSentRequests() {
+void Connection::checkSentRequests() {
 	// Remove very old (10 minutes) containers and resend requests.
 	auto removingIds = std::vector<mtpMsgId>();
 	auto requesting = false;
@@ -285,7 +256,7 @@ void ConnectionPrivate::checkSentRequests() {
 	}
 }
 
-void ConnectionPrivate::destroyAllConnections() {
+void Connection::destroyAllConnections() {
 	clearUnboundKeyCreator();
 	_waitForBetterTimer.cancel();
 	_waitForReceivedTimer.cancel();
@@ -294,67 +265,20 @@ void ConnectionPrivate::destroyAllConnections() {
 	_connection = nullptr;
 }
 
-ConnectionPrivate::ConnectionPrivate(
-	not_null<Instance*> instance,
-	not_null<QThread*> thread,
-	not_null<Connection*> owner,
-	std::shared_ptr<SessionData> data,
-	ShiftedDcId shiftedDcId)
-: QObject(nullptr)
-, _instance(instance)
-, _owner(owner)
-, _shiftedDcId(shiftedDcId)
-, _realDcType(_instance->dcOptions()->dcType(_shiftedDcId))
-, _currentDcType(_realDcType)
-, _state(DisconnectedState)
-, _retryTimer(thread, [=] { retryByTimer(); })
-, _oldConnectionTimer(thread, [=] { markConnectionOld(); })
-, _waitForConnectedTimer(thread, [=] { waitConnectedFailed(); })
-, _waitForReceivedTimer(thread, [=] { waitReceivedFailed(); })
-, _waitForBetterTimer(thread, [=] { waitBetterFailed(); })
-, _waitForReceived(kMinReceiveTimeout)
-, _waitForConnected(kMinConnectedTimeout)
-, _pingSender(thread, [=] { sendPingByTimer(); })
-, _checkSentRequestsTimer(thread, [=] { checkSentRequests(); })
-, _sessionData(std::move(data)) {
-	Expects(_shiftedDcId != 0);
-
-	moveToThread(thread);
-
-	connect(thread, &QThread::started, this, [=] {
-		_checkSentRequestsTimer.callEach(kCheckSentRequestsEach);
-		connectToServer();
-	});
-	connect(thread, &QThread::finished, this, [=] { finishAndDestroy(); });
-
-	connect(_sessionData->owner(), SIGNAL(authKeyChanged()), this, SLOT(updateAuthKey()), Qt::QueuedConnection);
-	connect(_sessionData->owner(), SIGNAL(needToRestart()), this, SLOT(restartNow()), Qt::QueuedConnection);
-	connect(_sessionData->owner(), SIGNAL(needToSend()), this, SLOT(tryToSend()), Qt::QueuedConnection);
-	connect(_sessionData->owner(), SIGNAL(needToPing()), this, SLOT(onPingSendForce()), Qt::QueuedConnection);
+void Connection::cdnConfigChanged() {
+	connectToServer(true);
 }
 
-ConnectionPrivate::~ConnectionPrivate() {
-	releaseKeyCreationOnFail();
-
-	Expects(_finished);
-	Expects(!_connection);
-	Expects(_testConnections.empty());
-}
-
-void ConnectionPrivate::onCDNConfigLoaded() {
-	restart();
-}
-
-int32 ConnectionPrivate::getShiftedDcId() const {
+int32 Connection::getShiftedDcId() const {
 	return _shiftedDcId;
 }
 
-void ConnectionPrivate::dcOptionsChanged() {
+void Connection::dcOptionsChanged() {
 	_retryTimeout = 1;
 	connectToServer(true);
 }
 
-int32 ConnectionPrivate::getState() const {
+int32 Connection::getState() const {
 	QReadLocker lock(&_stateMutex);
 	int32 result = _state;
 	if (_state < 0) {
@@ -368,7 +292,7 @@ int32 ConnectionPrivate::getState() const {
 	return result;
 }
 
-QString ConnectionPrivate::transport() const {
+QString Connection::transport() const {
 	QReadLocker lock(&_stateMutex);
 	if (!_connection || (_state < 0)) {
 		return QString();
@@ -378,8 +302,8 @@ QString ConnectionPrivate::transport() const {
 	return _connection->transport();
 }
 
-bool ConnectionPrivate::setState(int32 state, int32 ifState) {
-	if (ifState != Connection::UpdateAlways) {
+bool Connection::setState(int state, int ifState) {
+	if (ifState != kUpdateStateAlways) {
 		QReadLocker lock(&_stateMutex);
 		if (_state != ifState) {
 			return false;
@@ -402,7 +326,7 @@ bool ConnectionPrivate::setState(int32 state, int32 ifState) {
 	return true;
 }
 
-void ConnectionPrivate::resetSession() {
+void Connection::resetSession() {
 	MTP_LOG(_shiftedDcId, ("Resetting session!"));
 	_needSessionReset = false;
 
@@ -412,7 +336,7 @@ void ConnectionPrivate::resetSession() {
 	_sessionData->queueResetDone();
 }
 
-void ConnectionPrivate::changeSessionId() {
+void Connection::changeSessionId() {
 	auto sessionId = _sessionId;
 	do {
 		sessionId = openssl::RandomValue<uint64>();
@@ -429,13 +353,13 @@ void ConnectionPrivate::changeSessionId() {
 	_receivedMessageIds.clear();
 }
 
-uint32 ConnectionPrivate::nextRequestSeqNumber(bool needAck) {
+uint32 Connection::nextRequestSeqNumber(bool needAck) {
 	const auto result = _messagesCounter;
 	_messagesCounter += (needAck ? 1 : 0);
 	return result * 2 + (needAck ? 1 : 0);
 }
 
-bool ConnectionPrivate::realDcTypeChanged() {
+bool Connection::realDcTypeChanged() {
 	const auto now = _instance->dcOptions()->dcType(_shiftedDcId);
 	if (_realDcType == now) {
 		return false;
@@ -444,7 +368,7 @@ bool ConnectionPrivate::realDcTypeChanged() {
 	return true;
 }
 
-bool ConnectionPrivate::markSessionAsStarted() {
+bool Connection::markSessionAsStarted() {
 	if (_sessionMarkedAsStarted) {
 		return false;
 	}
@@ -452,7 +376,7 @@ bool ConnectionPrivate::markSessionAsStarted() {
 	return true;
 }
 
-mtpMsgId ConnectionPrivate::prepareToSend(
+mtpMsgId Connection::prepareToSend(
 		SerializedRequest &request,
 		mtpMsgId currentLastId,
 		bool forceNewMsgId) {
@@ -477,7 +401,7 @@ mtpMsgId ConnectionPrivate::prepareToSend(
 	return currentLastId;
 }
 
-mtpMsgId ConnectionPrivate::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
+mtpMsgId Connection::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
 	Expects(request->size() > 8);
 
 	const auto oldMsgId = request.getMsgId();
@@ -535,7 +459,7 @@ mtpMsgId ConnectionPrivate::replaceMsgId(SerializedRequest &request, mtpMsgId ne
 	return newId;
 }
 
-mtpMsgId ConnectionPrivate::placeToContainer(
+mtpMsgId Connection::placeToContainer(
 		SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
@@ -554,7 +478,7 @@ mtpMsgId ConnectionPrivate::placeToContainer(
 	return msgId;
 }
 
-void ConnectionPrivate::tryToSend() {
+void Connection::tryToSend() {
 	if (!_connection || !_keyId) {
 		return;
 	}
@@ -920,7 +844,7 @@ void ConnectionPrivate::tryToSend() {
 	sendSecureRequest(std::move(toSendRequest), needAnyResponse);
 }
 
-void ConnectionPrivate::retryByTimer() {
+void Connection::retryByTimer() {
 	if (_retryTimeout < 3) {
 		++_retryTimeout;
 	} else if (_retryTimeout == 3) {
@@ -931,18 +855,14 @@ void ConnectionPrivate::retryByTimer() {
 	connectToServer();
 }
 
-void ConnectionPrivate::restartNow() {
+void Connection::restartNow() {
 	_retryTimeout = 1;
 	_retryTimer.cancel();
 	restart();
 }
 
-void ConnectionPrivate::connectToServer(bool afterConfig) {
-	if (_finished) {
-		DEBUG_LOG(("MTP Error: "
-			"connectToServer() called for finished connection!"));
-		return;
-	} else if (afterConfig && (!_testConnections.empty() || _connection)) {
+void Connection::connectToServer(bool afterConfig) {
+	if (afterConfig && (!_testConnections.empty() || _connection)) {
 		return;
 	}
 
@@ -1046,7 +966,7 @@ void ConnectionPrivate::connectToServer(bool afterConfig) {
 	_waitForConnectedTimer.callOnce(_waitForConnected);
 }
 
-void ConnectionPrivate::restart() {
+void Connection::restart() {
 	DEBUG_LOG(("MTP Info: restarting Connection"));
 
 	_waitForReceivedTimer.cancel();
@@ -1066,7 +986,7 @@ void ConnectionPrivate::restart() {
 	setState(-_retryTimeout);
 }
 
-void ConnectionPrivate::onSentSome(uint64 size) {
+void Connection::onSentSome(uint64 size) {
 	if (!_waitForReceivedTimer.isActive()) {
 		auto remain = static_cast<uint64>(_waitForReceived);
 		if (!_oldConnection) {
@@ -1087,7 +1007,7 @@ void ConnectionPrivate::onSentSome(uint64 size) {
 	if (!_firstSentAt) _firstSentAt = crl::now();
 }
 
-void ConnectionPrivate::onReceivedSome() {
+void Connection::onReceivedSome() {
 	if (_oldConnection) {
 		_oldConnection = false;
 		DEBUG_LOG(("This connection marked as not old!"));
@@ -1105,13 +1025,13 @@ void ConnectionPrivate::onReceivedSome() {
 	}
 }
 
-void ConnectionPrivate::markConnectionOld() {
+void Connection::markConnectionOld() {
 	_oldConnection = true;
 	_waitForReceived = kMinReceiveTimeout;
 	DEBUG_LOG(("This connection marked as old! _waitForReceived now %1ms").arg(_waitForReceived));
 }
 
-void ConnectionPrivate::sendPingByTimer() {
+void Connection::sendPingByTimer() {
 	if (_pingId) {
 		// _pingSendAt: when to send next ping (lastPingAt + kPingSendAfter)
 		// could be equal to zero.
@@ -1130,7 +1050,7 @@ void ConnectionPrivate::sendPingByTimer() {
 	}
 }
 
-void ConnectionPrivate::onPingSendForce() {
+void Connection::sendPingForce() {
 	if (!_pingId) {
 		_pingSendAt = 0;
 		DEBUG_LOG(("Will send ping!"));
@@ -1138,7 +1058,7 @@ void ConnectionPrivate::onPingSendForce() {
 	}
 }
 
-void ConnectionPrivate::waitReceivedFailed() {
+void Connection::waitReceivedFailed() {
 	Expects(_connectionOptions != nullptr);
 
 	if (!_connectionOptions->useTcp) {
@@ -1158,7 +1078,7 @@ void ConnectionPrivate::waitReceivedFailed() {
 	InvokeQueued(this, [=] { connectToServer(); });
 }
 
-void ConnectionPrivate::waitConnectedFailed() {
+void Connection::waitConnectedFailed() {
 	DEBUG_LOG(("MTP Info: can't connect in %1ms").arg(_waitForConnected));
 	auto maxTimeout = kMaxConnectedTimeout;
 	for (const auto &connection : _testConnections) {
@@ -1174,46 +1094,29 @@ void ConnectionPrivate::waitConnectedFailed() {
 	InvokeQueued(this, [=] { connectToServer(); });
 }
 
-void ConnectionPrivate::waitBetterFailed() {
+void Connection::waitBetterFailed() {
 	confirmBestConnection();
 }
 
-void ConnectionPrivate::connectingTimedOut() {
+void Connection::connectingTimedOut() {
 	for (const auto &connection : _testConnections) {
 		connection.data->timedOut();
 	}
 	doDisconnect();
 }
 
-void ConnectionPrivate::doDisconnect() {
+void Connection::doDisconnect() {
 	destroyAllConnections();
 	setState(DisconnectedState);
 }
 
-void ConnectionPrivate::finishAndDestroy() {
-	doDisconnect();
-	_finished = true;
-	const auto connection = _owner;
-	const auto instance = _instance;
-	InvokeQueued(instance, [=] {
-		instance->connectionFinished(connection);
-	});
-	deleteLater();
-}
-
-void ConnectionPrivate::requestCDNConfig() {
-	connect(
-		_instance,
-		SIGNAL(cdnConfigLoaded()),
-		this,
-		SLOT(onCDNConfigLoaded()),
-		Qt::UniqueConnection);
+void Connection::requestCDNConfig() {
 	InvokeQueued(_instance, [instance = _instance] {
 		instance->requestCDNConfig();
 	});
 }
 
-void ConnectionPrivate::handleReceived() {
+void Connection::handleReceived() {
 	Expects(_encryptionKey != nullptr);
 
 	onReceivedSome();
@@ -1413,7 +1316,7 @@ void ConnectionPrivate::handleReceived() {
 	}
 }
 
-ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
+Connection::HandleResult Connection::handleOneReceived(
 		const mtpPrime *from,
 		const mtpPrime *end,
 		uint64 msgId,
@@ -1931,7 +1834,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleOneReceived(
 	return HandleResult::Success;
 }
 
-ConnectionPrivate::HandleResult ConnectionPrivate::handleBindResponse(
+Connection::HandleResult Connection::handleBindResponse(
 		mtpMsgId requestMsgId,
 		const mtpBuffer &response) {
 	if (!_keyCreator || !_bindMsgId || _bindMsgId != requestMsgId) {
@@ -1959,7 +1862,7 @@ ConnectionPrivate::HandleResult ConnectionPrivate::handleBindResponse(
 	Unexpected("Result of BoundKeyCreator::handleBindResponse.");
 }
 
-mtpBuffer ConnectionPrivate::ungzip(const mtpPrime *from, const mtpPrime *end) const {
+mtpBuffer Connection::ungzip(const mtpPrime *from, const mtpPrime *end) const {
 	mtpBuffer result; // * 4 because of mtpPrime type
 	result.resize(0);
 
@@ -2011,7 +1914,7 @@ mtpBuffer ConnectionPrivate::ungzip(const mtpPrime *from, const mtpPrime *end) c
 	return result;
 }
 
-bool ConnectionPrivate::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 serverTime, uint64 serverSalt) {
+bool Connection::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 serverTime, uint64 serverSalt) {
 	uint32 idsCount = ids.size();
 
 	for (uint32 i = 0; i < idsCount; ++i) {
@@ -2026,7 +1929,7 @@ bool ConnectionPrivate::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 s
 	return false;
 }
 
-void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
+void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 	uint32 idsCount = ids.size();
 
 	DEBUG_LOG(("Message Info: requests acked, ids %1").arg(LogIdsVector(ids)));
@@ -2120,7 +2023,7 @@ void ConnectionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byRespon
 	}
 }
 
-void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked) {
+void Connection::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked) {
 	uint32 idsCount = ids.size();
 	if (!idsCount) {
 		DEBUG_LOG(("Message Info: void ids vector in handleMsgsStates()"));
@@ -2163,7 +2066,7 @@ void ConnectionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByt
 	}
 }
 
-void ConnectionPrivate::clearSpecialMsgId(mtpMsgId msgId) {
+void Connection::clearSpecialMsgId(mtpMsgId msgId) {
 	if (msgId == _pingMsgId) {
 		_pingMsgId = 0;
 		_pingId = 0;
@@ -2172,7 +2075,7 @@ void ConnectionPrivate::clearSpecialMsgId(mtpMsgId msgId) {
 	}
 }
 
-void ConnectionPrivate::resend(
+void Connection::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
 		bool forceContainer) {
@@ -2211,7 +2114,7 @@ void ConnectionPrivate::resend(
 	}
 }
 
-void ConnectionPrivate::resendAll() {
+void Connection::resendAll() {
 	auto toResend = std::vector<mtpMsgId>();
 
 	auto lock = QReadLocker(_sessionData->haveSentMutex());
@@ -2230,7 +2133,7 @@ void ConnectionPrivate::resendAll() {
 	_sessionData->queueSendAnything();
 }
 
-void ConnectionPrivate::onConnected(
+void Connection::onConnected(
 		not_null<AbstractConnection*> connection) {
 	disconnect(connection, &AbstractConnection::connected, nullptr, nullptr);
 	if (!connection->isConnected()) {
@@ -2264,7 +2167,7 @@ void ConnectionPrivate::onConnected(
 	}
 }
 
-void ConnectionPrivate::onDisconnected(
+void Connection::onDisconnected(
 		not_null<AbstractConnection*> connection) {
 	removeTestConnection(connection);
 
@@ -2276,7 +2179,7 @@ void ConnectionPrivate::onDisconnected(
 	}
 }
 
-void ConnectionPrivate::confirmBestConnection() {
+void Connection::confirmBestConnection() {
 	if (_waitForBetterTimer.isActive()) {
 		return;
 	}
@@ -2300,7 +2203,7 @@ void ConnectionPrivate::confirmBestConnection() {
 	checkAuthKey();
 }
 
-void ConnectionPrivate::removeTestConnection(
+void Connection::removeTestConnection(
 		not_null<AbstractConnection*> connection) {
 	_testConnections.erase(
 		ranges::remove(
@@ -2310,7 +2213,7 @@ void ConnectionPrivate::removeTestConnection(
 		end(_testConnections));
 }
 
-void ConnectionPrivate::checkAuthKey() {
+void Connection::checkAuthKey() {
 	if (_keyId) {
 		authKeyChecked();
 	} else if (_instance->isKeysDestroyer()) {
@@ -2321,7 +2224,7 @@ void ConnectionPrivate::checkAuthKey() {
 	}
 }
 
-void ConnectionPrivate::updateAuthKey() {
+void Connection::updateAuthKey() {
 	if (_instance->isKeysDestroyer() || _keyCreator || !_connection) {
 		return;
 	}
@@ -2339,7 +2242,7 @@ void ConnectionPrivate::updateAuthKey() {
 	}
 }
 
-void ConnectionPrivate::setCurrentKeyId(uint64 newKeyId) {
+void Connection::setCurrentKeyId(uint64 newKeyId) {
 	if (_keyId == newKeyId) {
 		return;
 	}
@@ -2349,7 +2252,7 @@ void ConnectionPrivate::setCurrentKeyId(uint64 newKeyId) {
 	changeSessionId();
 }
 
-void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&encryptionKey) {
+void Connection::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 	_encryptionKey = std::move(encryptionKey);
 	const auto newKeyId = _encryptionKey ? _encryptionKey->keyId() : 0;
 	if (_keyId) {
@@ -2391,7 +2294,7 @@ void ConnectionPrivate::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 	}
 }
 
-bool ConnectionPrivate::destroyOldEnoughPersistentKey() {
+bool Connection::destroyOldEnoughPersistentKey() {
 	Expects(_keyCreator != nullptr);
 
 	const auto key = _keyCreator->bindPersistentKey();
@@ -2410,7 +2313,7 @@ bool ConnectionPrivate::destroyOldEnoughPersistentKey() {
 	return true;
 }
 
-DcType ConnectionPrivate::tryAcquireKeyCreation() {
+DcType Connection::tryAcquireKeyCreation() {
 	if (_keyCreator) {
 		return _currentDcType;
 	} else if (_instance->isKeysDestroyer()) {
@@ -2484,7 +2387,7 @@ DcType ConnectionPrivate::tryAcquireKeyCreation() {
 	return forceUseRegular ? DcType::Regular : _realDcType;
 }
 
-void ConnectionPrivate::authKeyChecked() {
+void Connection::authKeyChecked() {
 	connect(_connection, &AbstractConnection::receivedData, [=] {
 		handleReceived();
 	});
@@ -2497,7 +2400,7 @@ void ConnectionPrivate::authKeyChecked() {
 	_sessionData->queueNeedToResumeAndSend();
 }
 
-void ConnectionPrivate::onError(
+void Connection::onError(
 		not_null<AbstractConnection*> connection,
 		qint32 errorCode) {
 	if (errorCode == -429) {
@@ -2517,7 +2420,7 @@ void ConnectionPrivate::onError(
 	}
 }
 
-void ConnectionPrivate::handleError(int errorCode) {
+void Connection::handleError(int errorCode) {
 	destroyAllConnections();
 	_waitForConnectedTimer.cancel();
 
@@ -2529,7 +2432,7 @@ void ConnectionPrivate::handleError(int errorCode) {
 	}
 }
 
-void ConnectionPrivate::destroyTemporaryKey() {
+void Connection::destroyTemporaryKey() {
 	if (_instance->isKeysDestroyer()) {
 		LOG(("MTP Info: -404 error received in destroyer %1, assuming key was destroyed.").arg(_shiftedDcId));
 		_instance->keyWasPossiblyDestroyed(_shiftedDcId);
@@ -2544,7 +2447,7 @@ void ConnectionPrivate::destroyTemporaryKey() {
 	restart();
 }
 
-bool ConnectionPrivate::sendSecureRequest(
+bool Connection::sendSecureRequest(
 		SerializedRequest &&request,
 		bool needAnyResponse) {
 #ifdef TDESKTOP_MTPROTO_OLD
@@ -2628,7 +2531,7 @@ bool ConnectionPrivate::sendSecureRequest(
 	return true;
 }
 
-mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
+mtpRequestId Connection::wasSent(mtpMsgId msgId) const {
 	if (msgId == _pingMsgId || msgId == _bindMsgId) {
 		return mtpRequestId(0xFFFFFFFF);
 	}
@@ -2651,13 +2554,13 @@ mtpRequestId ConnectionPrivate::wasSent(mtpMsgId msgId) const {
 	return 0;
 }
 
-void ConnectionPrivate::clearUnboundKeyCreator() {
+void Connection::clearUnboundKeyCreator() {
 	if (_keyCreator) {
 		_keyCreator->stop();
 	}
 }
 
-void ConnectionPrivate::releaseKeyCreationOnFail() {
+void Connection::releaseKeyCreationOnFail() {
 	if (!_keyCreator) {
 		return;
 	}
@@ -2665,8 +2568,5 @@ void ConnectionPrivate::releaseKeyCreationOnFail() {
 	_sessionData->releaseKeyCreationOnFail();
 }
 
-void ConnectionPrivate::stop() {
-}
-
 } // namespace internal
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index fddd75bd7..bd2384b52 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -29,72 +29,34 @@ class Instance;
 namespace internal {
 
 class AbstractConnection;
-class ConnectionPrivate;
 class SessionData;
 class RSAPublicKey;
 struct ConnectionOptions;
 
-class Connection {
+class Connection : public QObject {
 public:
-	enum ConnectionType {
-		TcpConnection,
-		HttpConnection
-	};
-
-	Connection(not_null<Instance*> instance);
-	~Connection();
-
-	void start(std::shared_ptr<SessionData> data, ShiftedDcId shiftedDcId);
-
-	void kill();
-	void waitTillFinish();
-
-	static const int UpdateAlways = 666;
-
-	int32 state() const;
-	QString transport() const;
-
-private:
-	not_null<Instance*> _instance;
-	std::unique_ptr<QThread> _thread;
-	ConnectionPrivate *_private = nullptr;
-	rpl::lifetime _lifetime;
-
-};
-
-class ConnectionPrivate : public QObject {
-	Q_OBJECT
-
-public:
-	ConnectionPrivate(
+	Connection(
 		not_null<Instance*> instance,
 		not_null<QThread*> thread,
-		not_null<Connection*> owner,
 		std::shared_ptr<SessionData> data,
 		ShiftedDcId shiftedDcId);
-	~ConnectionPrivate();
+	~Connection();
 
-	void stop();
-
-	int32 getShiftedDcId() const;
+	[[nodiscard]] int32 getShiftedDcId() const;
 	void dcOptionsChanged();
+	void cdnConfigChanged();
 
-	int32 getState() const;
-	QString transport() const;
-
-public slots:
-	void restartNow();
-
-	void onPingSendForce();
-
-	// Sessions signals, when we need to send something
-	void tryToSend();
+	[[nodiscard]] int32 getState() const;
+	[[nodiscard]] QString transport() const;
 
 	void updateAuthKey();
-
-	void onCDNConfigLoaded();
+	void restartNow();
+	void sendPingForce();
+	void tryToSend();
 
 private:
+	static constexpr auto kUpdateStateAlways = 666;
+
 	struct TestConnection {
 		ConnectionPointer data;
 		int priority = 0;
@@ -113,7 +75,6 @@ private:
 	void connectingTimedOut();
 	void doDisconnect();
 	void restart();
-	void finishAndDestroy();
 	void requestCDNConfig();
 	void handleError(int errorCode);
 	void onError(
@@ -167,7 +128,7 @@ private:
 	void handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked);
 
 	// _sessionDataMutex must be locked for read.
-	bool setState(int32 state, int32 ifState = Connection::UpdateAlways);
+	bool setState(int state, int ifState = kUpdateStateAlways);
 
 	void appendTestConnection(
 		DcOptions::Variants::Protocol protocol,
@@ -206,13 +167,12 @@ private:
 	[[nodiscard]] bool realDcTypeChanged();
 
 	const not_null<Instance*> _instance;
-	const not_null<Connection*> _owner;
 	const ShiftedDcId _shiftedDcId = 0;
 	DcType _realDcType = DcType();
 	DcType _currentDcType = DcType();
 
 	mutable QReadWriteLock _stateMutex;
-	int32 _state = DisconnectedState;
+	int _state = DisconnectedState;
 
 	bool _needSessionReset = false;
 
@@ -241,8 +201,6 @@ private:
 	base::Timer _pingSender;
 	base::Timer _checkSentRequestsTimer;
 
-	bool _finished = false;
-
 	std::shared_ptr<SessionData> _sessionData;
 	std::unique_ptr<ConnectionOptions> _connectionOptions;
 	AuthKeyPtr _encryptionKey;
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index cbac04e31..34dfd0cbe 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -68,6 +68,11 @@ public:
 	: _that(that)
 	, _lock(&_that->_useThroughLockers) {
 	}
+
+	void unlock() {
+		_lock.unlock();
+	}
+
 	~WriteLocker() {
 		_that->computeCdnDcIds();
 	}
@@ -84,6 +89,10 @@ public:
 	: _lock(&that->_useThroughLockers) {
 	}
 
+	void unlock() {
+		_lock.unlock();
+	}
+
 private:
 	QReadLocker _lock;
 
@@ -517,6 +526,10 @@ rpl::producer<DcId> DcOptions::changed() const {
 	return _changed.events();
 }
 
+rpl::producer<> DcOptions::cdnConfigChanged() const {
+	return _cdnConfigChanged.events();
+}
+
 std::vector<DcId> DcOptions::configEnumDcIds() const {
 	auto result = std::vector<DcId>();
 	{
@@ -553,20 +566,23 @@ DcType DcOptions::dcType(ShiftedDcId shiftedDcId) const {
 void DcOptions::setCDNConfig(const MTPDcdnConfig &config) {
 	WriteLocker lock(this);
 	_cdnPublicKeys.clear();
-	for_const (auto &publicKey, config.vpublic_keys().v) {
-		Expects(publicKey.type() == mtpc_cdnPublicKey);
-		const auto &keyData = publicKey.c_cdnPublicKey();
-		const auto keyBytes = bytes::make_span(keyData.vpublic_key().v);
-		auto key = internal::RSAPublicKey(keyBytes);
-		if (key.valid()) {
-			_cdnPublicKeys[keyData.vdc_id().v].emplace(
-				key.fingerprint(),
-				std::move(key));
-		} else {
-			LOG(("MTP Error: could not read this public RSA key:"));
-			LOG((qs(keyData.vpublic_key())));
-		}
+	for (const auto &key : config.vpublic_keys().v) {
+		key.match([&](const MTPDcdnPublicKey &data) {
+			const auto keyBytes = bytes::make_span(data.vpublic_key().v);
+			auto key = internal::RSAPublicKey(keyBytes);
+			if (key.valid()) {
+				_cdnPublicKeys[data.vdc_id().v].emplace(
+					key.fingerprint(),
+					std::move(key));
+			} else {
+				LOG(("MTP Error: could not read this public RSA key:"));
+				LOG((qs(data.vpublic_key())));
+			}
+		});
 	}
+	lock.unlock();
+
+	_cdnConfigChanged.fire({});
 }
 
 bool DcOptions::hasCDNKeysForDc(DcId dcId) const {
diff --git a/Telegram/SourceFiles/mtproto/dc_options.h b/Telegram/SourceFiles/mtproto/dc_options.h
index 4c21e5567..ca0293b9c 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.h
+++ b/Telegram/SourceFiles/mtproto/dc_options.h
@@ -67,6 +67,7 @@ public:
 	QByteArray serialize() const;
 
 	[[nodiscard]] rpl::producer<DcId> changed() const;
+	[[nodiscard]] rpl::producer<> cdnConfigChanged() const;
 	void setFromList(const MTPVector<MTPDcOption> &options);
 	void addFromList(const MTPVector<MTPDcOption> &options);
 	void addFromOther(DcOptions &&options);
@@ -141,6 +142,7 @@ private:
 	mutable QReadWriteLock _useThroughLockers;
 
 	rpl::event_stream<DcId> _changed;
+	rpl::event_stream<> _cdnConfigChanged;
 
 	// True when we have overriden options from a .tdesktop-endpoints file.
 	bool _immutable = false;
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 3f4a91e63..3fb10a63b 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -71,6 +71,7 @@ public:
 	[[nodiscard]] rpl::producer<DcId> dcTemporaryKeyChanged() const;
 	[[nodiscard]] AuthKeysList getKeysForWrite() const;
 	void addKeysForDestroy(AuthKeysList &&keys);
+	[[nodiscard]] rpl::producer<> allKeysDestroyed() const;
 
 	[[nodiscard]] not_null<DcOptions*> dcOptions();
 
@@ -106,10 +107,6 @@ public:
 	void removeDc(ShiftedDcId shiftedDcId);
 	void unpaused();
 
-	void queueQuittingConnection(
-		std::unique_ptr<Connection> &&connection);
-	void connectionFinished(not_null<Connection*> connection);
-
 	void sendRequest(
 		mtpRequestId requestId,
 		SerializedRequest &&request,
@@ -216,8 +213,6 @@ private:
 	base::flat_map<ShiftedDcId, std::unique_ptr<Session>> _sessions;
 	std::vector<std::unique_ptr<Session>> _sessionsToDestroy;
 
-	std::vector<std::unique_ptr<Connection>> _connectionsToDestroy;
-
 	std::unique_ptr<ConfigLoader> _configLoader;
 	std::unique_ptr<DomainResolver> _domainResolver;
 	std::unique_ptr<SpecialConfigRequest> _httpUnixtimeLoader;
@@ -229,6 +224,8 @@ private:
 	base::flat_map<DcId, AuthKeyPtr> _keysForWrite;
 	base::flat_map<ShiftedDcId, mtpRequestId> _logoutGuestRequestIds;
 
+	rpl::event_stream<> _allKeysDestroyed;
+
 	// holds dcWithShift for request to this dc or -dc for request to main dc
 	std::map<mtpRequestId, ShiftedDcId> _requestsByDc;
 	mutable QMutex _requestByDcLock;
@@ -480,13 +477,10 @@ void Instance::Private::requestCDNConfig() {
 		MTPhelp_GetCdnConfig()
 	).done([this](const MTPCdnConfig &result) {
 		_cdnConfigLoadRequestId = 0;
-
-		Expects(result.type() == mtpc_cdnConfig);
-		dcOptions()->setCDNConfig(result.c_cdnConfig());
-
+		result.match([&](const MTPDcdnConfig &data) {
+			dcOptions()->setCDNConfig(data);
+		});
 		Local::writeSettings();
-
-		emit _instance->cdnConfigLoaded();
 	}).send();
 }
 
@@ -759,6 +753,10 @@ void Instance::Private::addKeysForDestroy(AuthKeysList &&keys) {
 	}
 }
 
+rpl::producer<> Instance::Private::allKeysDestroyed() const {
+	return _allKeysDestroyed.events();
+}
+
 not_null<DcOptions*> Instance::Private::dcOptions() {
 	return _dcOptions;
 }
@@ -777,22 +775,6 @@ void Instance::Private::unpaused() {
 	}
 }
 
-void Instance::Private::queueQuittingConnection(
-		std::unique_ptr<Connection> &&connection) {
-	_connectionsToDestroy.push_back(std::move(connection));
-}
-
-void Instance::Private::connectionFinished(
-		not_null<Connection*> connection) {
-	const auto i = ranges::find(
-		_connectionsToDestroy,
-		connection.get(),
-		&std::unique_ptr<Connection>::get);
-	if (i != _connectionsToDestroy.end()) {
-		_connectionsToDestroy.erase(i);
-	}
-}
-
 void Instance::Private::configLoadDone(const MTPConfig &result) {
 	Expects(result.type() == mtpc_config);
 
@@ -1582,7 +1564,7 @@ void Instance::Private::completedKeyDestroy(ShiftedDcId shiftedDcId) {
 	_keysForWrite.erase(shiftedDcId);
 	killSession(shiftedDcId);
 	if (_dcenters.empty()) {
-		emit _instance->allKeysDestroyed();
+		_allKeysDestroyed.fire({});
 	}
 }
 
@@ -1674,6 +1656,10 @@ QString Instance::langPackName() const {
 	return Lang::Current().langPackName();
 }
 
+rpl::producer<> Instance::allKeysDestroyed() const {
+	return _private->allKeysDestroyed();
+}
+
 void Instance::requestConfig() {
 	_private->requestConfig();
 }
@@ -1698,10 +1684,6 @@ void Instance::requestCDNConfig() {
 	_private->requestCDNConfig();
 }
 
-void Instance::connectionFinished(not_null<Connection*> connection) {
-	_private->connectionFinished(connection);
-}
-
 void Instance::restart() {
 	_private->restart();
 }
@@ -1784,11 +1766,6 @@ void Instance::unpaused() {
 	_private->unpaused();
 }
 
-void Instance::queueQuittingConnection(
-		std::unique_ptr<Connection> &&connection) {
-	_private->queueQuittingConnection(std::move(connection));
-}
-
 void Instance::setUpdatesHandler(RPCDoneHandlerPtr onDone) {
 	_private->setUpdatesHandler(onDone);
 }
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index f28f635cc..2eb80fb8d 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -15,7 +15,6 @@ namespace internal {
 
 class Dcenter;
 class Session;
-class Connection;
 
 [[nodiscard]] int GetNextRequestId();
 
@@ -61,6 +60,8 @@ public:
 	[[nodiscard]] QString cloudLangCode() const;
 	[[nodiscard]] QString langPackName() const;
 
+	[[nodiscard]] rpl::producer<> allKeysDestroyed() const;
+
 	// Thread-safe.
 	[[nodiscard]] QString deviceModel() const;
 	[[nodiscard]] QString systemVersion() const;
@@ -90,8 +91,6 @@ public:
 
 	void unpaused();
 
-	void queueQuittingConnection(std::unique_ptr<internal::Connection> &&connection);
-
 	void setUpdatesHandler(RPCDoneHandlerPtr onDone);
 	void setGlobalFailHandler(RPCFailHandlerPtr onFail);
 	void setStateChangedHandler(Fn<void(ShiftedDcId shiftedDcId, int32 state)> handler);
@@ -126,8 +125,6 @@ public:
 
 	void syncHttpUnixtime();
 
-	void connectionFinished(not_null<internal::Connection*> connection);
-
 	void sendAnything(ShiftedDcId shiftedDcId = 0, crl::time msCanWait = 0);
 
 	template <typename Request>
@@ -199,8 +196,6 @@ public:
 	}
 
 signals:
-	void cdnConfigLoaded();
-	void allKeysDestroyed();
 	void proxyDomainResolved(
 		QString host,
 		QStringList ips,
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 66cf7f31e..ec9e0d58a 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -148,8 +148,7 @@ Session::Session(
 	not_null<Instance*> instance,
 	ShiftedDcId shiftedDcId,
 	not_null<Dcenter*> dc)
-: QObject()
-, _instance(instance)
+: _instance(instance)
 , _shiftedDcId(shiftedDcId)
 , _dc(dc)
 , _data(std::make_shared<SessionData>(this))
@@ -157,6 +156,19 @@ Session::Session(
 	_timeouter.callEach(1000);
 	refreshOptions();
 	watchDcKeyChanges();
+	watchDcOptionsChanges();
+}
+
+Session::~Session() {
+	Expects(!_connection);
+	Expects(!_thread);
+
+	if (_myKeyCreation != CreatingKeyType::None) {
+		releaseKeyCreationOnFail();
+	}
+	for (const auto &thread : _destroyingThreads) {
+		thread->wait();
+	}
 }
 
 void Session::watchDcKeyChanges() {
@@ -166,13 +178,59 @@ void Session::watchDcKeyChanges() {
 	}) | rpl::start_with_next([=] {
 		DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, "
 			"emitting authKeyChanged(), dcWithShift %1").arg(_shiftedDcId));
-		emit authKeyChanged();
+		if (const auto connection = _connection) {
+			InvokeQueued(connection, [=] {
+				connection->updateAuthKey();
+			});
+		}
 	}, _lifetime);
 }
 
+void Session::watchDcOptionsChanges() {
+	_instance->dcOptions()->changed(
+	) | rpl::filter([=](DcId dcId) {
+		return (BareDcId(_shiftedDcId) == dcId) && (_connection != nullptr);
+	}) | rpl::start_with_next([=] {
+		InvokeQueued(_connection, [connection = _connection] {
+			connection->dcOptionsChanged();
+		});
+	}, _lifetime);
+
+	if (_instance->dcOptions()->dcType(_shiftedDcId) == DcType::Cdn) {
+		_instance->dcOptions()->cdnConfigChanged(
+		) | rpl::filter([=] {
+			return (_connection != nullptr);
+		}) | rpl::start_with_next([=] {
+			InvokeQueued(_connection, [connection = _connection] {
+				connection->cdnConfigChanged();
+			});
+		}, _lifetime);
+	}
+}
+
 void Session::start() {
-	_connection = std::make_unique<Connection>(_instance);
-	_connection->start(_data, _shiftedDcId);
+	killConnection();
+
+	_thread = std::make_unique<QThread>();
+	const auto thread = _thread.get();
+
+	connect(thread, &QThread::finished, [=] {
+		InvokeQueued(this, [=] {
+			const auto i = ranges::find(
+				_destroyingThreads,
+				thread,
+				&std::unique_ptr<QThread>::get);
+			if (i != _destroyingThreads.end()) {
+				_destroyingThreads.erase(i);
+			}
+		});
+	});
+	_connection = new Connection(
+		_instance,
+		thread,
+		_data,
+		_shiftedDcId);
+	thread->start();
 }
 
 bool Session::rpcErrorOccured(
@@ -188,7 +246,11 @@ void Session::restart() {
 		return;
 	}
 	refreshOptions();
-	emit needToRestart();
+	if (const auto connection = _connection) {
+		InvokeQueued(connection, [=] {
+			connection->restartNow();
+		});
+	}
 }
 
 void Session::refreshOptions() {
@@ -221,14 +283,11 @@ void Session::reInitConnection() {
 
 void Session::stop() {
 	if (_killed) {
-		DEBUG_LOG(("Session Error: can't kill a killed session"));
+		DEBUG_LOG(("Session Error: can't stop a killed session"));
 		return;
 	}
 	DEBUG_LOG(("Session Info: stopping session dcWithShift %1").arg(_shiftedDcId));
-	if (_connection) {
-		_connection->kill();
-		_instance->queueQuittingConnection(std::move(_connection));
-	}
+	killConnection();
 }
 
 void Session::kill() {
@@ -286,12 +345,15 @@ void Session::needToResumeAndSend() {
 		DEBUG_LOG(("Session Info: resuming session dcWithShift %1").arg(_shiftedDcId));
 		start();
 	}
-	if (_ping) {
-		_ping = false;
-		emit needToPing();
-	} else {
-		emit needToSend();
-	}
+	const auto connection = _connection;
+	const auto ping = base::take(_ping);
+	InvokeQueued(connection, [=] {
+		if (ping) {
+			connection->sendPingForce();
+		} else {
+			connection->tryToSend();
+		}
+	});
 }
 
 void Session::connectionStateChange(int newState) {
@@ -323,7 +385,7 @@ int32 Session::requestState(mtpRequestId requestId) const {
 
 	bool connected = false;
 	if (_connection) {
-		int32 s = _connection->state();
+		const auto s = _connection->getState();
 		if (s == ConnectedState) {
 			connected = true;
 		} else if (s == ConnectingState || s == DisconnectedState) {
@@ -352,7 +414,7 @@ int32 Session::getState() const {
 	int32 result = -86400000;
 
 	if (_connection) {
-		int32 s = _connection->state();
+		const auto s = _connection->getState();
 		if (s == ConnectedState) {
 			return s;
 		} else if (s == ConnectingState || s == DisconnectedState) {
@@ -448,7 +510,8 @@ void Session::releaseKeyCreationOnFail() {
 }
 
 void Session::notifyDcConnectionInited() {
-	DEBUG_LOG(("MTP Info: emitting MTProtoDC::connectionWasInited(), dcWithShift %1").arg(_shiftedDcId));
+	DEBUG_LOG(("MTP Info: MTProtoDC::connectionWasInited(), dcWithShift %1"
+		).arg(_shiftedDcId));
 	_dc->setConnectionInited();
 }
 
@@ -514,11 +577,19 @@ void Session::tryToReceive() {
 	}
 }
 
-Session::~Session() {
-	if (_myKeyCreation != CreatingKeyType::None) {
-		releaseKeyCreationOnFail();
+void Session::killConnection() {
+	Expects(!_thread || _connection);
+
+	if (!_connection) {
+		return;
 	}
-	Assert(_connection == nullptr);
+
+	base::take(_connection)->deleteLater();
+	_destroyingThreads.push_back(base::take(_thread));
+	_destroyingThreads.back()->quit();
+
+	Ensures(_connection == nullptr);
+	Ensures(_thread == nullptr);
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index ce4ef83a3..6a9ced818 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -56,7 +56,7 @@ struct ConnectionOptions {
 class Session;
 class SessionData {
 public:
-	SessionData(not_null<Session*> creator) : _owner(creator) {
+	explicit SessionData(not_null<Session*> creator) : _owner(creator) {
 	}
 
 	void notifyConnectionInited(const ConnectionOptions &options);
@@ -92,11 +92,6 @@ public:
 		return _receivedUpdates;
 	}
 
-	// Warning! Valid only in constructor, _owner is guaranteed != null.
-	[[nodiscard]] not_null<Session*> owner() {
-		return _owner;
-	}
-
 	// Connection -> Session interface.
 	void queueTryToReceive();
 	void queueNeedToResumeAndSend();
@@ -139,8 +134,6 @@ private:
 };
 
 class Session : public QObject {
-	Q_OBJECT
-
 public:
 	// Main thread.
 	Session(
@@ -180,8 +173,8 @@ public:
 
 	void ping();
 	void cancel(mtpRequestId requestId, mtpMsgId msgId);
-	int32 requestState(mtpRequestId requestId) const;
-	int32 getState() const;
+	int requestState(mtpRequestId requestId) const;
+	int getState() const;
 	QString transport() const;
 
 	void tryToReceive();
@@ -190,23 +183,26 @@ public:
 	void resetDone();
 	void sendAnything(crl::time msCanWait = 0);
 
-signals:
-	void authKeyChanged();
-	void needToSend();
-	void needToPing();
-	void needToRestart();
-
 private:
 	void watchDcKeyChanges();
+	void watchDcOptionsChanges();
 
-	bool rpcErrorOccured(mtpRequestId requestId, const RPCFailHandlerPtr &onFail, const RPCError &err);
+	void killConnection();
+
+	bool rpcErrorOccured(
+		mtpRequestId requestId,
+		const RPCFailHandlerPtr &onFail,
+		const RPCError &err);
 
 	const not_null<Instance*> _instance;
 	const ShiftedDcId _shiftedDcId = 0;
 	const not_null<Dcenter*> _dc;
 	const std::shared_ptr<SessionData> _data;
 
-	std::unique_ptr<Connection> _connection;
+	std::unique_ptr<QThread> _thread;
+	std::vector<std::unique_ptr<QThread>> _destroyingThreads;
+
+	Connection *_connection = nullptr;
 
 	bool _killed = false;
 	bool _needToReceive = false;

From 64535251e8f6d51183b260c52e79c543a845411c Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 27 Nov 2019 18:09:56 +0300
Subject: [PATCH 64/91] Use limited number of threads in MTP.

---
 Telegram/SourceFiles/mtproto/connection.cpp   |  2 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 69 ++++++++++++++++++-
 Telegram/SourceFiles/mtproto/session.cpp      | 30 ++------
 Telegram/SourceFiles/mtproto/session.h        |  5 +-
 4 files changed, 74 insertions(+), 32 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index b17f50b88..05cc6c457 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -139,7 +139,7 @@ Connection::Connection(
 
 	moveToThread(thread);
 
-	connect(thread, &QThread::started, this, [=] {
+	InvokeQueued(this, [=] {
 		_checkSentRequestsTimer.callEach(kCheckSentRequestsEach);
 		connectToServer();
 	});
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 3fb10a63b..a24caabee 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -170,6 +170,7 @@ private:
 	Session *findSession(ShiftedDcId shiftedDcId);
 	not_null<Session*> startSession(ShiftedDcId shiftedDcId);
 	Session *removeSession(ShiftedDcId shiftedDcId);
+	[[nodiscard]] not_null<QThread*> getThreadForDc(ShiftedDcId shiftedDcId);
 
 	void applyDomainIps(
 		const QString &host,
@@ -200,6 +201,10 @@ private:
 	const not_null<DcOptions*> _dcOptions;
 	const Instance::Mode _mode = Instance::Mode::Normal;
 
+	std::unique_ptr<QThread> _mainSessionThread;
+	std::unique_ptr<QThread> _otherSessionsThread;
+	std::vector<std::unique_ptr<QThread>> _fileSessionThreads;
+
 	QString _deviceModel;
 	QString _systemVersion;
 
@@ -263,6 +268,8 @@ Instance::Private::Private(
 , _instance(instance)
 , _dcOptions(options)
 , _mode(mode) {
+	const auto idealThreadPoolSize = QThread::idealThreadCount();
+	_fileSessionThreads.resize(2 * std::max(idealThreadPoolSize / 2, 1));
 }
 
 void Instance::Private::start(Config &&config) {
@@ -1486,11 +1493,11 @@ not_null<Session*> Instance::Private::startSession(ShiftedDcId shiftedDcId) {
 	Expects(BareDcId(shiftedDcId) != 0);
 
 	const auto dc = getDcById(shiftedDcId);
+	const auto thread = getThreadForDc(shiftedDcId);
 	const auto result = _sessions.emplace(
 		shiftedDcId,
-		std::make_unique<Session>(_instance, shiftedDcId, dc)
+		std::make_unique<Session>(_instance, thread, shiftedDcId, dc)
 	).first->second.get();
-	result->start();
 	if (isKeysDestroyer()) {
 		scheduleKeyDestroy(shiftedDcId);
 	}
@@ -1509,6 +1516,47 @@ Session *Instance::Private::removeSession(ShiftedDcId shiftedDcId) {
 	return _sessionsToDestroy.back().get();
 }
 
+
+not_null<QThread*> Instance::Private::getThreadForDc(
+		ShiftedDcId shiftedDcId) {
+	static const auto EnsureStarted = [](std::unique_ptr<QThread> &thread) {
+		if (!thread) {
+			thread = std::make_unique<QThread>();
+			thread->start();
+		}
+		return thread.get();
+	};
+	static const auto FindOne = [](
+			std::vector<std::unique_ptr<QThread>> &threads,
+			int index,
+			bool shift) {
+		Expects(!threads.empty());
+		Expects(!(threads.size() % 2));
+
+		const auto count = int(threads.size());
+		index %= count;
+		if (index >= count / 2) {
+			index = (count - 1) - (index - count / 2);
+		}
+		if (shift) {
+			index = (index + count / 2) % count;
+		}
+		return EnsureStarted(threads[index]);
+	};
+	if (shiftedDcId == BareDcId(shiftedDcId)) {
+		return EnsureStarted(_mainSessionThread);
+	} else if (isDownloadDcId(shiftedDcId)) {
+		const auto index = GetDcIdShift(shiftedDcId) - kBaseDownloadDcShift;
+		const auto composed = index + BareDcId(shiftedDcId);
+		return FindOne(_fileSessionThreads, composed, false);
+	} else if (isUploadDcId(shiftedDcId)) {
+		const auto index = GetDcIdShift(shiftedDcId) - kBaseUploadDcShift;
+		const auto composed = index + BareDcId(shiftedDcId);
+		return FindOne(_fileSessionThreads, composed, true);
+	}
+	return EnsureStarted(_otherSessionsThread);
+}
+
 void Instance::Private::scheduleKeyDestroy(ShiftedDcId shiftedDcId) {
 	Expects(isKeysDestroyer());
 
@@ -1616,6 +1664,23 @@ void Instance::Private::prepareToDestroy() {
 		session->kill();
 	}
 	_mainSession = nullptr;
+
+	auto threads = std::vector<std::unique_ptr<QThread>>();
+	threads.push_back(base::take(_mainSessionThread));
+	threads.push_back(base::take(_otherSessionsThread));
+	for (auto &thread : base::take(_fileSessionThreads)) {
+		threads.push_back(std::move(thread));
+	}
+	for (const auto &thread : threads) {
+		if (thread) {
+			thread->quit();
+		}
+	}
+	for (const auto &thread : threads) {
+		if (thread) {
+			thread->wait();
+		}
+	}
 }
 
 Instance::Instance(not_null<DcOptions*> options, Mode mode, Config &&config)
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index ec9e0d58a..00294cd3d 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -146,29 +146,28 @@ void SessionData::detach() {
 
 Session::Session(
 	not_null<Instance*> instance,
+	not_null<QThread*> thread,
 	ShiftedDcId shiftedDcId,
 	not_null<Dcenter*> dc)
 : _instance(instance)
 , _shiftedDcId(shiftedDcId)
 , _dc(dc)
 , _data(std::make_shared<SessionData>(this))
+, _thread(thread)
 , _sender([=] { needToResumeAndSend(); }) {
 	_timeouter.callEach(1000);
 	refreshOptions();
 	watchDcKeyChanges();
 	watchDcOptionsChanges();
+	start();
 }
 
 Session::~Session() {
 	Expects(!_connection);
-	Expects(!_thread);
 
 	if (_myKeyCreation != CreatingKeyType::None) {
 		releaseKeyCreationOnFail();
 	}
-	for (const auto &thread : _destroyingThreads) {
-		thread->wait();
-	}
 }
 
 void Session::watchDcKeyChanges() {
@@ -210,27 +209,11 @@ void Session::watchDcOptionsChanges() {
 
 void Session::start() {
 	killConnection();
-
-	_thread = std::make_unique<QThread>();
-	const auto thread = _thread.get();
-
-	connect(thread, &QThread::finished, [=] {
-		InvokeQueued(this, [=] {
-			const auto i = ranges::find(
-				_destroyingThreads,
-				thread,
-				&std::unique_ptr<QThread>::get);
-			if (i != _destroyingThreads.end()) {
-				_destroyingThreads.erase(i);
-			}
-		});
-	});
 	_connection = new Connection(
 		_instance,
-		thread,
+		_thread.get(),
 		_data,
 		_shiftedDcId);
-	thread->start();
 }
 
 bool Session::rpcErrorOccured(
@@ -578,18 +561,13 @@ void Session::tryToReceive() {
 }
 
 void Session::killConnection() {
-	Expects(!_thread || _connection);
-
 	if (!_connection) {
 		return;
 	}
 
 	base::take(_connection)->deleteLater();
-	_destroyingThreads.push_back(base::take(_thread));
-	_destroyingThreads.back()->quit();
 
 	Ensures(_connection == nullptr);
-	Ensures(_thread == nullptr);
 }
 
 } // namespace internal
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 6a9ced818..81b484afe 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -138,6 +138,7 @@ public:
 	// Main thread.
 	Session(
 		not_null<Instance*> instance,
+		not_null<QThread*> thread,
 		ShiftedDcId shiftedDcId,
 		not_null<Dcenter*> dc);
 	~Session();
@@ -198,9 +199,7 @@ private:
 	const ShiftedDcId _shiftedDcId = 0;
 	const not_null<Dcenter*> _dc;
 	const std::shared_ptr<SessionData> _data;
-
-	std::unique_ptr<QThread> _thread;
-	std::vector<std::unique_ptr<QThread>> _destroyingThreads;
+	const not_null<QThread*> _thread;
 
 	Connection *_connection = nullptr;
 

From ae98e4ae4413a34cca9fbf6023dedc77180e2391 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 29 Nov 2019 09:55:22 +0300
Subject: [PATCH 65/91] Support file reference refresh in Export.

---
 .../export/data/export_data_types.cpp         |  26 ++++
 .../export/data/export_data_types.h           |   8 ++
 .../SourceFiles/export/export_api_wrap.cpp    | 130 ++++++++++++++++--
 Telegram/SourceFiles/export/export_api_wrap.h |  17 ++-
 4 files changed, 171 insertions(+), 10 deletions(-)

diff --git a/Telegram/SourceFiles/export/data/export_data_types.cpp b/Telegram/SourceFiles/export/data/export_data_types.cpp
index 1b006d2df..768ef6a90 100644
--- a/Telegram/SourceFiles/export/data/export_data_types.cpp
+++ b/Telegram/SourceFiles/export/data/export_data_types.cpp
@@ -209,6 +209,32 @@ Utf8String FillLeft(const Utf8String &data, int length, char filler) {
 	return result;
 }
 
+bool RefreshFileReference(FileLocation &to, const FileLocation &from) {
+	if (to.dcId != from.dcId || to.data.type() != from.data.type()) {
+		return false;
+	}
+	if (to.data.type() == mtpc_inputPhotoFileLocation) {
+		const auto &toData = to.data.c_inputPhotoFileLocation();
+		const auto &fromData = from.data.c_inputPhotoFileLocation();
+		if (toData.vid().v != fromData.vid().v
+			|| toData.vthumb_size().v != fromData.vthumb_size().v) {
+			return false;
+		}
+		to = from;
+		return true;
+	} else if (to.data.type() == mtpc_inputDocumentFileLocation) {
+		const auto &toData = to.data.c_inputDocumentFileLocation();
+		const auto &fromData = from.data.c_inputDocumentFileLocation();
+		if (toData.vid().v != fromData.vid().v
+			|| toData.vthumb_size().v != fromData.vthumb_size().v) {
+			return false;
+		}
+		to = from;
+		return true;
+	}
+	return false;
+}
+
 Image ParseMaxImage(
 		const MTPDphoto &photo,
 		const QString &suggestedPath) {
diff --git a/Telegram/SourceFiles/export/data/export_data_types.h b/Telegram/SourceFiles/export/data/export_data_types.h
index 588fc2fae..ee4a14182 100644
--- a/Telegram/SourceFiles/export/data/export_data_types.h
+++ b/Telegram/SourceFiles/export/data/export_data_types.h
@@ -60,6 +60,8 @@ struct FileLocation {
 	}
 };
 
+bool RefreshFileReference(FileLocation &to, const FileLocation &from);
+
 struct File {
 	enum class SkipReason {
 		None,
@@ -526,6 +528,12 @@ struct Message {
 	const Image &thumb() const;
 };
 
+struct FileOrigin {
+	int split = 0;
+	MTPInputPeer peer;
+	int32 messageId = 0;
+};
+
 Message ParseMessage(
 	ParseMediaContext &context,
 	const MTPMessage &data,
diff --git a/Telegram/SourceFiles/export/export_api_wrap.cpp b/Telegram/SourceFiles/export/export_api_wrap.cpp
index c47c61379..b2fc69789 100644
--- a/Telegram/SourceFiles/export/export_api_wrap.cpp
+++ b/Telegram/SourceFiles/export/export_api_wrap.cpp
@@ -181,6 +181,7 @@ struct ApiWrap::FileProcess {
 	FnMut<void(const QString &relativePath)> done;
 
 	Data::FileLocation location;
+	Data::FileOrigin origin;
 	int offset = 0;
 	int size = 0;
 
@@ -400,6 +401,9 @@ auto ApiWrap::fileRequest(const Data::FileLocation &location, int offset) {
 		} else if (result.type() == qstr("LOCATION_INVALID")
 			|| result.type() == qstr("VERSION_INVALID")) {
 			filePartUnavailable();
+		} else if (result.code() == 400
+			&& result.type().startsWith(qstr("FILE_REFERENCE_"))) {
+			filePartRefreshReference(offset);
 		} else {
 			error(std::move(result));
 		}
@@ -696,6 +700,7 @@ void ApiWrap::requestOtherData(
 	_otherDataProcess->file.suggestedPath = suggestedPath;
 	loadFile(
 		_otherDataProcess->file,
+		Data::FileOrigin(),
 		[](FileProgress progress) { return true; },
 		[=](const QString &result) { otherDataDone(result); });
 }
@@ -780,6 +785,7 @@ void ApiWrap::loadNextUserpic() {
 		; ++_userpicsProcess->fileIndex) {
 		const auto ready = processFileLoad(
 			list[_userpicsProcess->fileIndex].image.file,
+			Data::FileOrigin(),
 			[=](FileProgress value) { return loadUserpicProgress(value); },
 			[=](const QString &path) { loadUserpicDone(path); });
 		if (!ready) {
@@ -1382,6 +1388,24 @@ void ApiWrap::loadMessagesFiles(Data::MessagesSlice &&slice) {
 	loadNextMessageFile();
 }
 
+Data::Message *ApiWrap::currentFileMessage() const {
+	Expects(_chatProcess != nullptr);
+	Expects(_chatProcess->slice.has_value());
+
+	return &_chatProcess->slice->list[_chatProcess->fileIndex];
+}
+
+Data::FileOrigin ApiWrap::currentFileMessageOrigin() const {
+	Expects(_chatProcess != nullptr);
+	Expects(_chatProcess->slice.has_value());
+
+	auto result = Data::FileOrigin();
+	result.messageId = currentFileMessage()->id;
+	result.peer = _chatProcess->info.input;
+	result.split = _chatProcess->info.splits[_chatProcess->localSplitIndex];
+	return result;
+}
+
 void ApiWrap::loadNextMessageFile() {
 	Expects(_chatProcess != nullptr);
 	Expects(_chatProcess->slice.has_value());
@@ -1398,9 +1422,10 @@ void ApiWrap::loadNextMessageFile() {
 		};
 		const auto ready = processFileLoad(
 			list[_chatProcess->fileIndex].file(),
+			currentFileMessageOrigin(),
 			fileProgress,
 			[=](const QString &path) { loadMessageFileDone(path); },
-			&list[_chatProcess->fileIndex]);
+			currentFileMessage());
 		if (!ready) {
 			return;
 		}
@@ -1409,9 +1434,10 @@ void ApiWrap::loadNextMessageFile() {
 		};
 		const auto thumbReady = processFileLoad(
 			list[_chatProcess->fileIndex].thumb().file,
+			currentFileMessageOrigin(),
 			thumbProgress,
 			[=](const QString &path) { loadMessageThumbDone(path); },
-			&list[_chatProcess->fileIndex]);
+			currentFileMessage());
 		if (!thumbReady) {
 			return;
 		}
@@ -1501,6 +1527,7 @@ void ApiWrap::finishMessages() {
 
 bool ApiWrap::processFileLoad(
 		Data::File &file,
+		const Data::FileOrigin &origin,
 		Fn<bool(FileProgress)> progress,
 		FnMut<void(QString)> done,
 		Data::Message *message) {
@@ -1512,7 +1539,7 @@ bool ApiWrap::processFileLoad(
 	} else if (!file.location && file.content.isEmpty()) {
 		file.skipReason = SkipReason::Unavailable;
 		return true;
-	} else if (writePreloadedFile(file)) {
+	} else if (writePreloadedFile(file, origin)) {
 		return !file.relativePath.isEmpty();
 	}
 
@@ -1548,11 +1575,13 @@ bool ApiWrap::processFileLoad(
 		file.skipReason = SkipReason::FileSize;
 		return true;
 	}
-	loadFile(file, std::move(progress), std::move(done));
+	loadFile(file, origin, std::move(progress), std::move(done));
 	return false;
 }
 
-bool ApiWrap::writePreloadedFile(Data::File &file) {
+bool ApiWrap::writePreloadedFile(
+		Data::File &file,
+		const Data::FileOrigin &origin) {
 	Expects(_settings != nullptr);
 
 	using namespace Output;
@@ -1561,7 +1590,7 @@ bool ApiWrap::writePreloadedFile(Data::File &file) {
 		file.relativePath = *path;
 		return true;
 	} else if (!file.content.isEmpty()) {
-		const auto process = prepareFileProcess(file);
+		const auto process = prepareFileProcess(file, origin);
 		if (const auto result = process->file.writeBlock(file.content)) {
 			file.relativePath = process->relativePath;
 			_fileCache->save(file.location, file.relativePath);
@@ -1575,13 +1604,14 @@ bool ApiWrap::writePreloadedFile(Data::File &file) {
 
 void ApiWrap::loadFile(
 		const Data::File &file,
+		const Data::FileOrigin &origin,
 		Fn<bool(FileProgress)> progress,
 		FnMut<void(QString)> done) {
 	Expects(_fileProcess == nullptr);
 	Expects(file.location.dcId != 0
 		|| file.location.data.type() == mtpc_inputTakeoutFileLocation);
 
-	_fileProcess = prepareFileProcess(file);
+	_fileProcess = prepareFileProcess(file, origin);
 	_fileProcess->progress = std::move(progress);
 	_fileProcess->done = std::move(done);
 
@@ -1598,7 +1628,9 @@ void ApiWrap::loadFile(
 	loadFilePart();
 }
 
-auto ApiWrap::prepareFileProcess(const Data::File &file) const
+auto ApiWrap::prepareFileProcess(
+	const Data::File &file,
+	const Data::FileOrigin &origin) const
 -> std::unique_ptr<FileProcess> {
 	Expects(_settings != nullptr);
 
@@ -1611,6 +1643,7 @@ auto ApiWrap::prepareFileProcess(const Data::File &file) const
 	result->relativePath = relativePath;
 	result->location = file.location;
 	result->size = file.size;
+	result->origin = origin;
 	return result;
 }
 
@@ -1705,6 +1738,87 @@ void ApiWrap::filePartDone(int offset, const MTPupload_File &result) {
 	process->done(process->relativePath);
 }
 
+void ApiWrap::filePartRefreshReference(int offset) {
+	Expects(_fileProcess != nullptr);
+
+	const auto &origin = _fileProcess->origin;
+	if (!origin.messageId) {
+		error("FILE_REFERENCE error for non-message file.");
+		return;
+	}
+	if (origin.peer.type() == mtpc_inputPeerChannel
+		|| origin.peer.type() == mtpc_inputPeerChannelFromMessage) {
+		const auto channel = (origin.peer.type() == mtpc_inputPeerChannel)
+			? MTP_inputChannel(
+				origin.peer.c_inputPeerChannel().vchannel_id(),
+				origin.peer.c_inputPeerChannel().vaccess_hash())
+			: MTP_inputChannelFromMessage(
+				origin.peer.c_inputPeerChannelFromMessage().vpeer(),
+				origin.peer.c_inputPeerChannelFromMessage().vmsg_id(),
+				origin.peer.c_inputPeerChannelFromMessage().vchannel_id());
+		mainRequest(MTPchannels_GetMessages(
+			channel,
+			MTP_vector<MTPInputMessage>(
+				1,
+				MTP_inputMessageID(MTP_int(origin.messageId)))
+		)).fail([=](const RPCError &error) {
+			filePartUnavailable();
+			return true;
+		}).done([=](const MTPmessages_Messages &result) {
+			filePartExtractReference(offset, result);
+		}).send();
+	} else {
+		splitRequest(origin.split, MTPmessages_GetMessages(
+			MTP_vector<MTPInputMessage>(
+				1,
+				MTP_inputMessageID(MTP_int(origin.messageId)))
+		)).fail([=](const RPCError &error) {
+			filePartUnavailable();
+			return true;
+		}).done([=](const MTPmessages_Messages &result) {
+			filePartExtractReference(offset, result);
+		}).send();
+	}
+}
+
+void ApiWrap::filePartExtractReference(
+		int offset,
+		const MTPmessages_Messages &result) {
+	Expects(_fileProcess != nullptr);
+
+	result.match([&](const MTPDmessages_messagesNotModified &data) {
+		error("Unexpected messagesNotModified received.");
+	}, [&](const auto &data) {
+		auto context = Data::ParseMediaContext();
+		const auto messages = Data::ParseMessagesSlice(
+			context,
+			data.vmessages(),
+			data.vusers(),
+			data.vchats(),
+			_chatProcess->info.relativePath);
+		for (const auto &message : messages.list) {
+			if (message.id == _fileProcess->origin.messageId) {
+				const auto refresh1 = Data::RefreshFileReference(
+					_fileProcess->location,
+					message.file().location);
+				const auto refresh2 = Data::RefreshFileReference(
+					_fileProcess->location,
+					message.thumb().file.location);
+				if (refresh1 || refresh2) {
+					fileRequest(
+						_fileProcess->location,
+						offset
+					).done([=](const MTPupload_File &result) {
+						filePartDone(offset, result);
+					}).send();
+					return;
+				}
+			}
+		}
+		filePartUnavailable();
+	});
+}
+
 void ApiWrap::filePartUnavailable() {
 	Expects(_fileProcess != nullptr);
 	Expects(!_fileProcess->requests.empty());
diff --git a/Telegram/SourceFiles/export/export_api_wrap.h b/Telegram/SourceFiles/export/export_api_wrap.h
index c0f28d819..6f3016ab6 100644
--- a/Telegram/SourceFiles/export/export_api_wrap.h
+++ b/Telegram/SourceFiles/export/export_api_wrap.h
@@ -23,6 +23,7 @@ struct DialogsInfo;
 struct DialogInfo;
 struct MessagesSlice;
 struct Message;
+struct FileOrigin;
 } // namespace Data
 
 namespace Output {
@@ -159,21 +160,33 @@ private:
 	void finishMessagesSlice();
 	void finishMessages();
 
+	[[nodiscard]] Data::Message *currentFileMessage() const;
+	[[nodiscard]] Data::FileOrigin currentFileMessageOrigin() const;
+
 	bool processFileLoad(
 		Data::File &file,
+		const Data::FileOrigin &origin,
 		Fn<bool(FileProgress)> progress,
 		FnMut<void(QString)> done,
 		Data::Message *message = nullptr);
 	std::unique_ptr<FileProcess> prepareFileProcess(
-		const Data::File &file) const;
-	bool writePreloadedFile(Data::File &file);
+		const Data::File &file,
+		const Data::FileOrigin &origin) const;
+	bool writePreloadedFile(
+		Data::File &file,
+		const Data::FileOrigin &origin);
 	void loadFile(
 		const Data::File &file,
+		const Data::FileOrigin &origin,
 		Fn<bool(FileProgress)> progress,
 		FnMut<void(QString)> done);
 	void loadFilePart();
 	void filePartDone(int offset, const MTPupload_File &result);
 	void filePartUnavailable();
+	void filePartRefreshReference(int offset);
+	void filePartExtractReference(
+		int offset,
+		const MTPmessages_Messages &result);
 
 	template <typename Request>
 	class RequestBuilder;

From b3a255b3f1bffa2ed003954d517568f10f6ec706 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 29 Nov 2019 12:09:15 +0300
Subject: [PATCH 66/91] Fix file references in webpage collages.

---
 Telegram/SourceFiles/data/data_file_origin.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Telegram/SourceFiles/data/data_file_origin.cpp b/Telegram/SourceFiles/data/data_file_origin.cpp
index b2932a5b9..05ccf3f5e 100644
--- a/Telegram/SourceFiles/data/data_file_origin.cpp
+++ b/Telegram/SourceFiles/data/data_file_origin.cpp
@@ -33,6 +33,12 @@ struct FileReferenceAccumulator {
 		}, [](const MTPDdocumentEmpty &data) {
 		});
 	}
+	void push(const MTPPage &data) {
+		data.match([&](const auto &data) {
+			push(data.vphotos());
+			push(data.vdocuments());
+		});
+	}
 	void push(const MTPWallPaper &data) {
 		data.match([&](const MTPDwallPaper &data) {
 			push(data.vdocument());
@@ -57,6 +63,9 @@ struct FileReferenceAccumulator {
 			if (const auto photo = data.vphoto()) {
 				push(*photo);
 			}
+			if (const auto page = data.vcached_page()) {
+				push(*page);
+			}
 		}, [](const auto &data) {
 		});
 	}

From eea508066c7013debcd98e3b9f8f5242b360b3e9 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 29 Nov 2019 15:36:16 +0300
Subject: [PATCH 67/91] Closed alpha version 1.9.1.6.

---
 Telegram/Resources/uwp/AppX/AppxManifest.xml | 2 +-
 Telegram/Resources/winrc/Telegram.rc         | 8 ++++----
 Telegram/Resources/winrc/Updater.rc          | 8 ++++----
 Telegram/SourceFiles/core/version.h          | 2 +-
 Telegram/build/version                       | 2 +-
 5 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Telegram/Resources/uwp/AppX/AppxManifest.xml b/Telegram/Resources/uwp/AppX/AppxManifest.xml
index 044d61af4..268818013 100644
--- a/Telegram/Resources/uwp/AppX/AppxManifest.xml
+++ b/Telegram/Resources/uwp/AppX/AppxManifest.xml
@@ -9,7 +9,7 @@
   <Identity Name="TelegramMessengerLLP.TelegramDesktop"
     ProcessorArchitecture="ARCHITECTURE"
     Publisher="CN=536BC709-8EE1-4478-AF22-F0F0F26FF64A"
-    Version="1.9.1.4" />
+    Version="1.9.1.6" />
   <Properties>
     <DisplayName>Telegram Desktop</DisplayName>
     <PublisherDisplayName>Telegram FZ-LLC</PublisherDisplayName>
diff --git a/Telegram/Resources/winrc/Telegram.rc b/Telegram/Resources/winrc/Telegram.rc
index 9a17a3f2d..2e9d22a42 100644
--- a/Telegram/Resources/winrc/Telegram.rc
+++ b/Telegram/Resources/winrc/Telegram.rc
@@ -33,8 +33,8 @@ IDI_ICON1               ICON                    "..\\art\\icon256.ico"
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,4
- PRODUCTVERSION 1,9,1,4
+ FILEVERSION 1,9,1,6
+ PRODUCTVERSION 1,9,1,6
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -51,10 +51,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop"
-            VALUE "FileVersion", "1.9.1.4"
+            VALUE "FileVersion", "1.9.1.6"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.4"
+            VALUE "ProductVersion", "1.9.1.6"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/Resources/winrc/Updater.rc b/Telegram/Resources/winrc/Updater.rc
index b99e85983..eaf84e301 100644
--- a/Telegram/Resources/winrc/Updater.rc
+++ b/Telegram/Resources/winrc/Updater.rc
@@ -24,8 +24,8 @@ LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,4
- PRODUCTVERSION 1,9,1,4
+ FILEVERSION 1,9,1,6
+ PRODUCTVERSION 1,9,1,6
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -42,10 +42,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop Updater"
-            VALUE "FileVersion", "1.9.1.4"
+            VALUE "FileVersion", "1.9.1.6"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.4"
+            VALUE "ProductVersion", "1.9.1.6"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/SourceFiles/core/version.h b/Telegram/SourceFiles/core/version.h
index f643ad225..fadf33d70 100644
--- a/Telegram/SourceFiles/core/version.h
+++ b/Telegram/SourceFiles/core/version.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001004ULL)
+#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001006ULL)
 
 #ifdef TDESKTOP_OFFICIAL_TARGET
 #define TDESKTOP_ALPHA_VERSION TDESKTOP_REQUESTED_ALPHA_VERSION
diff --git a/Telegram/build/version b/Telegram/build/version
index f27ed1fce..a3fb38894 100644
--- a/Telegram/build/version
+++ b/Telegram/build/version
@@ -3,4 +3,4 @@ AppVersionStrMajor 1.9
 AppVersionStrSmall 1.9.1
 AppVersionStr      1.9.1
 BetaChannel        0
-AlphaVersion       1009001004
+AlphaVersion       1009001006

From cbebcb1bc9c159aeba3a6ebbf8372a366fe5002d Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 12:16:15 +0300
Subject: [PATCH 68/91] Fix notification about a new mtproto session.

---
 Telegram/SourceFiles/main/main_account.cpp | 29 ++++++++++++++--------
 Telegram/SourceFiles/main/main_account.h   |  2 ++
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/Telegram/SourceFiles/main/main_account.cpp b/Telegram/SourceFiles/main/main_account.cpp
index 82030ea93..bfc07862c 100644
--- a/Telegram/SourceFiles/main/main_account.cpp
+++ b/Telegram/SourceFiles/main/main_account.cpp
@@ -341,16 +341,8 @@ void Account::startMtp() {
 	_mtp->setUpdatesHandler(::rpcDone([=](
 			const mtpPrime *from,
 			const mtpPrime *end) {
-		auto newSession = MTPNewSession();
-		auto updates = MTPUpdates();
-		if (updates.read(from, end)) {
-			_mtpUpdates.fire(std::move(updates));
-		} else if (newSession.read(from, end)) {
-			_mtpNewSessionCreated.fire({});
-		} else {
-			return false;
-		}
-		return true;
+		return checkForUpdates(from, end)
+			|| checkForNewSession(from, end);
 	}));
 	_mtp->setGlobalFailHandler(::rpcFail([=](const RPCError &error) {
 		if (sessionExists()) {
@@ -390,6 +382,23 @@ void Account::startMtp() {
 	_mtpValue = _mtp.get();
 }
 
+bool Account::checkForUpdates(const mtpPrime *from, const mtpPrime *end) {
+	auto updates = MTPUpdates();
+	if (!updates.read(from, end)) {
+		return false;
+	}
+	_mtpUpdates.fire(std::move(updates));
+	return true;
+}
+
+bool Account::checkForNewSession(const mtpPrime *from, const mtpPrime *end) {
+	auto newSession = MTPNewSession();
+	if (!newSession.read(from, end)) {
+		return false;
+	}
+	_mtpNewSessionCreated.fire({});
+	return true;
+}
 
 void Account::logOut() {
 	if (_loggingOut) {
diff --git a/Telegram/SourceFiles/main/main_account.h b/Telegram/SourceFiles/main/main_account.h
index 374cad860..d4f9b58e8 100644
--- a/Telegram/SourceFiles/main/main_account.h
+++ b/Telegram/SourceFiles/main/main_account.h
@@ -83,6 +83,8 @@ private:
 		Settings &&settings);
 	void watchProxyChanges();
 	void watchSessionChanges();
+	bool checkForUpdates(const mtpPrime *from, const mtpPrime *end);
+	bool checkForNewSession(const mtpPrime *from, const mtpPrime *end);
 
 	void destroyMtpKeys(MTP::AuthKeysList &&keys);
 	void resetAuthorizationKeys();

From 9caac426ef8bc55814d3cdb98d8499779ecce92c Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 12:40:53 +0300
Subject: [PATCH 69/91] Correctly check container lifetime.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 72 +++++++++-------
 Telegram/SourceFiles/mtproto/mtp_instance.cpp | 85 +------------------
 Telegram/SourceFiles/mtproto/mtp_instance.h   |  3 -
 Telegram/SourceFiles/mtproto/session.cpp      |  6 +-
 4 files changed, 50 insertions(+), 116 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 05cc6c457..1e5f17c6a 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -218,42 +218,52 @@ int16 Connection::getProtocolDcId() const {
 void Connection::checkSentRequests() {
 	// Remove very old (10 minutes) containers and resend requests.
 	auto removingIds = std::vector<mtpMsgId>();
+	auto restarting = false;
 	auto requesting = false;
 	{
 		QReadLocker locker(_sessionData->haveSentMutex());
 		auto &haveSent = _sessionData->haveSentMap();
 		const auto haveSentCount = haveSent.size();
-		auto now = crl::now();
+		const auto now = crl::now();
+		const auto checkAfter = kCheckSentRequestTimeout;
 		for (const auto &[msgId, request] : haveSent) {
 			if (request.isStateRequest()) {
 				continue;
 			} else if (request.isSentContainer()) {
-				if (base::unixtime::now()
-					> int32(msgId >> 32) + kContainerLives) {
+				if (now > request->lastSentTime + kContainerLives) {
 					removingIds.push_back(msgId);
+					DEBUG_LOG(("MTP Info: Removing old container %1, "
+						"sent: %2, now: %3, current unixtime: %4"
+						).arg(msgId
+						).arg(request->lastSentTime
+						).arg(now
+						).arg(base::unixtime::now()));
 				}
-			} else if (request->lastSentTime + kCheckSentRequestTimeout
-				< now) {
+			} else if (request->lastSentTime + checkAfter < now) {
 				// Need to check state.
 				request->lastSentTime = now;
-				if (_stateRequestData.emplace(msgId).second) {
+				if (_bindMsgId) {
+					restarting = true;
+				} else if (_stateRequestData.emplace(msgId).second) {
 					requesting = true;
 				}
 			}
 		}
 	}
-	if (requesting) {
-		_sessionData->queueSendAnything(kSendStateRequestWaiting);
-	}
 	if (!removingIds.empty()) {
 		QWriteLocker locker(_sessionData->haveSentMutex());
 		auto &haveSent = _sessionData->haveSentMap();
 		for (const auto msgId : removingIds) {
-			if (const auto removed = haveSent.take(msgId)) {
-				Assert(!(*removed)->requestId);
-			}
+			haveSent.remove(msgId);
 		}
 	}
+	if (restarting) {
+		DEBUG_LOG(("MTP Info: "
+			"Request state while key is not bound, restarting."));
+		restart();
+	} else if (requesting) {
+		_sessionData->queueSendAnything(kSendStateRequestWaiting);
+	}
 }
 
 void Connection::destroyAllConnections() {
@@ -479,7 +489,12 @@ mtpMsgId Connection::placeToContainer(
 }
 
 void Connection::tryToSend() {
-	if (!_connection || !_keyId) {
+	DEBUG_LOG(("MTP Info: tryToSend for dc %1.").arg(_shiftedDcId));
+	if (!_connection) {
+		DEBUG_LOG(("MTP Info: not yet connected in dc %1.").arg(_shiftedDcId));
+		return;
+	} else if (!_keyId) {
+		DEBUG_LOG(("MTP Info: not yet with auth key in dc %1.").arg(_shiftedDcId));
 		return;
 	}
 
@@ -1051,6 +1066,7 @@ void Connection::sendPingByTimer() {
 }
 
 void Connection::sendPingForce() {
+	DEBUG_LOG(("MTP Info: send ping force for dcWithShift %1.").arg(_shiftedDcId));
 	if (!_pingId) {
 		_pingSendAt = 0;
 		DEBUG_LOG(("Will send ping!"));
@@ -1496,14 +1512,20 @@ Connection::HandleResult Connection::handleOneReceived(
 			const auto requestId = wasSent(resendId);
 			if (requestId) {
 				LOG(("Message Error: "
-					"bad message notification received, "
-					"msgId %1, error_code %2, fatal: clearing callbacks"
+					"fatal bad message notification received, "
+					"msgId %1, error_code %2, requestId: %3"
 					).arg(badMsgId
 					).arg(errorCode
-					));
-				_instance->clearCallbacksDelayed({ 1, RPCCallbackClear(
-					requestId,
-					-errorCode) });
+					).arg(requestId));
+				auto response = mtpBuffer();
+				MTPRpcError(MTP_rpc_error(
+					MTP_int(500),
+					MTP_string("PROTOCOL_ERROR")
+				)).write(response);
+
+				// Save rpc_error for processing in the main thread.
+				QWriteLocker locker(_sessionData->haveReceivedMutex());
+				_sessionData->haveReceivedResponses().emplace(requestId, response);
 			} else {
 				DEBUG_LOG(("Message Error: "
 					"such message was not sent recently %1").arg(badMsgId));
@@ -2006,18 +2028,10 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 		DEBUG_LOG(("Message Info: removing some old acked sent msgIds %1").arg(ackedCount - kIdsBufferSize));
 		clearedBecauseTooOld.reserve(ackedCount - kIdsBufferSize);
 		while (ackedCount-- > kIdsBufferSize) {
-			auto i = _ackedIds.begin();
-			clearedBecauseTooOld.push_back(RPCCallbackClear(
-				i->second,
-				RPCError::TimeoutError));
-			_ackedIds.erase(i);
+			_ackedIds.erase(_ackedIds.begin());
 		}
 	}
 
-	if (!clearedBecauseTooOld.empty()) {
-		_instance->clearCallbacksDelayed(std::move(clearedBecauseTooOld));
-	}
-
 	if (toAckMore.size()) {
 		requestsAcked(toAckMore);
 	}
@@ -2260,7 +2274,7 @@ void Connection::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 			return;
 		}
 		setCurrentKeyId(0);
-		DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed, restarting..."
+		DEBUG_LOG(("MTP Info: auth_key id for dc %1 changed, restarting..."
 			).arg(_shiftedDcId));
 		if (_connection) {
 			restart();
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index a24caabee..2af0788f0 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -122,7 +122,6 @@ public:
 		const SerializedRequest &request,
 		RPCResponseHandler &&callbacks);
 	SerializedRequest getRequest(mtpRequestId requestId);
-	void clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids);
 	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
 	bool hasCallbacks(mtpRequestId requestId);
 	void globalCallback(const mtpPrime *from, const mtpPrime *end);
@@ -189,12 +188,6 @@ private:
 	std::optional<ShiftedDcId> changeRequestByDc(
 		mtpRequestId requestId, DcId newdc);
 
-	// RPCError::NoError means do not toggle onError callback.
-	void clearCallbacks(
-		mtpRequestId requestId,
-		int32 errorCode = RPCError::NoError);
-	void clearCallbacks(const std::vector<RPCCallbackClear> &ids);
-
 	void checkDelayedRequests();
 
 	const not_null<Instance*> _instance;
@@ -562,7 +555,9 @@ void Instance::Private::cancel(mtpRequestId requestId) {
 		const auto session = getSession(qAbs(*shiftedDcId));
 		session->cancel(requestId, msgId);
 	}
-	clearCallbacks(requestId);
+
+	QMutexLocker locker(&_parserMapLock);
+	_parserMap.erase(requestId);
 }
 
 // result < 0 means waiting for such count of ms.
@@ -993,76 +988,6 @@ SerializedRequest Instance::Private::getRequest(mtpRequestId requestId) {
 }
 
 
-void Instance::Private::clearCallbacks(mtpRequestId requestId, int32 errorCode) {
-	RPCResponseHandler h;
-	bool found = false;
-	{
-		QMutexLocker locker(&_parserMapLock);
-		auto it = _parserMap.find(requestId);
-		if (it != _parserMap.end()) {
-			h = it->second;
-			found = true;
-
-			_parserMap.erase(it);
-		}
-	}
-	if (errorCode && found) {
-		LOG(("API Error: callbacks cleared without handling! "
-			"Request: %1, error code: %2"
-			).arg(requestId
-			).arg(errorCode));
-		rpcErrorOccured(
-			requestId,
-			h,
-			RPCError::Local(
-				"CLEAR_CALLBACK",
-				QString("did not handle request %1, error code %2"
-				).arg(requestId
-				).arg(errorCode)));
-	}
-}
-
-void Instance::Private::clearCallbacksDelayed(
-		std::vector<RPCCallbackClear> &&ids) {
-	if (ids.empty()) {
-		return;
-	}
-
-	if (Logs::DebugEnabled()) {
-		auto idsString = QStringList();
-		idsString.reserve(ids.size());
-		for (auto &value : ids) {
-			idsString.push_back(QString::number(value.requestId));
-		}
-		DEBUG_LOG(("RPC Info: clear callbacks delayed, msgIds: %1"
-			).arg(idsString.join(", ")));
-	}
-
-	InvokeQueued(_instance, [=, list = std::move(ids)] {
-		clearCallbacks(list);
-	});
-}
-
-void Instance::Private::clearCallbacks(
-		const std::vector<RPCCallbackClear> &ids) {
-	Expects(!ids.empty());
-
-	for (const auto &clearRequest : ids) {
-		if (Logs::DebugEnabled()) {
-			QMutexLocker locker(&_parserMapLock);
-			const auto hasParsers = (_parserMap.find(clearRequest.requestId)
-				!= _parserMap.end());
-			DEBUG_LOG(("RPC Info: "
-				"clearing delayed callback %1, error code %2, parsers: %3"
-				).arg(clearRequest.requestId
-				).arg(clearRequest.errorCode
-				).arg(Logs::b(hasParsers)));
-		}
-		clearCallbacks(clearRequest.requestId, clearRequest.errorCode);
-		unregisterRequest(clearRequest.requestId);
-	}
-}
-
 void Instance::Private::execCallback(
 		mtpRequestId requestId,
 		const mtpPrime *from,
@@ -1859,10 +1784,6 @@ void Instance::onSessionReset(ShiftedDcId shiftedDcId) {
 	_private->onSessionReset(shiftedDcId);
 }
 
-void Instance::clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids) {
-	_private->clearCallbacksDelayed(std::move(ids));
-}
-
 void Instance::execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end) {
 	_private->execCallback(requestId, from, end);
 }
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 2eb80fb8d..7f6d7f463 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -100,9 +100,6 @@ public:
 	void onStateChange(ShiftedDcId shiftedDcId, int32 state);
 	void onSessionReset(ShiftedDcId shiftedDcId);
 
-	// Thread-safe.
-	void clearCallbacksDelayed(std::vector<RPCCallbackClear> &&ids);
-
 	void execCallback(mtpRequestId requestId, const mtpPrime *from, const mtpPrime *end);
 	bool hasCallbacks(mtpRequestId requestId);
 	void globalCallback(const mtpPrime *from, const mtpPrime *end);
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index 00294cd3d..b81859c27 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -175,10 +175,12 @@ void Session::watchDcKeyChanges() {
 	) | rpl::filter([=](DcId dcId) {
 		return (dcId == _shiftedDcId) || (dcId == BareDcId(_shiftedDcId));
 	}) | rpl::start_with_next([=] {
-		DEBUG_LOG(("AuthKey Info: Session::authKeyCreatedForDC slot, "
-			"emitting authKeyChanged(), dcWithShift %1").arg(_shiftedDcId));
+		DEBUG_LOG(("AuthKey Info: dcTemporaryKeyChanged in Session %1"
+			).arg(_shiftedDcId));
 		if (const auto connection = _connection) {
 			InvokeQueued(connection, [=] {
+				DEBUG_LOG(("AuthKey Info: calling Connection::updateAuthKey in Session %1"
+					).arg(_shiftedDcId));
 				connection->updateAuthKey();
 			});
 		}

From efaa3ba4537bbaa7021741e85fa618f368f424cf Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 13:32:09 +0300
Subject: [PATCH 70/91] Handle sent containers separately.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 290 +++++++++---------
 Telegram/SourceFiles/mtproto/connection.h     |   9 +-
 .../details/mtproto_serialized_request.cpp    |   6 -
 .../details/mtproto_serialized_request.h      |   3 -
 4 files changed, 154 insertions(+), 154 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 1e5f17c6a..7a800c524 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -56,8 +56,7 @@ constexpr auto kCheckSentRequestTimeout = 10 * crl::time(1000);
 // when resending request or checking its state.
 constexpr auto kSendStateRequestWaiting = crl::time(1000);
 
-// Container lives 10 minutes in haveSent map.
-constexpr auto kContainerLives = TimeId(600);
+constexpr auto kSentContainerLives = 600 * crl::time(1000);
 
 using namespace details;
 
@@ -216,8 +215,8 @@ int16 Connection::getProtocolDcId() const {
 }
 
 void Connection::checkSentRequests() {
-	// Remove very old (10 minutes) containers and resend requests.
-	auto removingIds = std::vector<mtpMsgId>();
+	clearOldContainers();
+
 	auto restarting = false;
 	auto requesting = false;
 	{
@@ -229,16 +228,6 @@ void Connection::checkSentRequests() {
 		for (const auto &[msgId, request] : haveSent) {
 			if (request.isStateRequest()) {
 				continue;
-			} else if (request.isSentContainer()) {
-				if (now > request->lastSentTime + kContainerLives) {
-					removingIds.push_back(msgId);
-					DEBUG_LOG(("MTP Info: Removing old container %1, "
-						"sent: %2, now: %3, current unixtime: %4"
-						).arg(msgId
-						).arg(request->lastSentTime
-						).arg(now
-						).arg(base::unixtime::now()));
-				}
 			} else if (request->lastSentTime + checkAfter < now) {
 				// Need to check state.
 				request->lastSentTime = now;
@@ -250,13 +239,6 @@ void Connection::checkSentRequests() {
 			}
 		}
 	}
-	if (!removingIds.empty()) {
-		QWriteLocker locker(_sessionData->haveSentMutex());
-		auto &haveSent = _sessionData->haveSentMap();
-		for (const auto msgId : removingIds) {
-			haveSent.remove(msgId);
-		}
-	}
 	if (restarting) {
 		DEBUG_LOG(("MTP Info: "
 			"Request state while key is not bound, restarting."));
@@ -266,6 +248,23 @@ void Connection::checkSentRequests() {
 	}
 }
 
+void Connection::clearOldContainers() {
+	const auto now = crl::now();
+	for (auto i = _sentContainers.begin(); i != _sentContainers.end();) {
+		if (now > i->second.sent + kSentContainerLives) {
+			DEBUG_LOG(("MTP Info: Removing old container %1, "
+				"sent: %2, now: %3, current unixtime: %4"
+				).arg(i->first
+				).arg(i->second.sent
+				).arg(now
+				).arg(base::unixtime::now()));
+			i = _sentContainers.erase(i);
+		} else {
+			++i;
+		}
+	}
+}
+
 void Connection::destroyAllConnections() {
 	clearUnboundKeyCreator();
 	_waitForBetterTimer.cancel();
@@ -452,34 +451,29 @@ mtpMsgId Connection::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
 		haveSent.erase(k);
 		haveSent.emplace(newId, request);
 	}
-
-	for (const auto &[requestId, sent] : haveSent) {
-		if (sent.isSentContainer()) {
-			const auto ids = (mtpMsgId *)(sent->data() + 8);
-			for (uint32 i = 0, l = (sent->size() - 8) >> 1; i < l; ++i) {
-				if (ids[i] == oldMsgId) {
-					ids[i] = newId;
-				}
+	for (auto &[msgId, container] : _sentContainers) {
+		for (auto &innerMsgId : container.messages) {
+			if (innerMsgId == oldMsgId) {
+				innerMsgId = newId;
 			}
 		}
 	}
-
 	request.setMsgId(newId);
 	request.setSeqNo(nextRequestSeqNumber(request.needAck()));
 	return newId;
 }
 
 mtpMsgId Connection::placeToContainer(
+		SentContainer &sentIdsWrap,
 		SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
-		mtpMsgId *&haveSentArr,
 		SerializedRequest &req) {
 	const auto msgId = prepareToSend(req, bigMsgId, forceNewMsgId);
 	if (msgId >= bigMsgId) {
 		bigMsgId = base::unixtime::mtproto_msg_id();
 	}
-	*(haveSentArr++) = msgId;
+	sentIdsWrap.messages.push_back(msgId);
 
 	uint32 from = toSendRequest->size(), len = req.messageSize();
 	toSendRequest->resize(from + len);
@@ -732,7 +726,7 @@ void Connection::tryToSend() {
 			}
 		} else { // send in container
 			bool willNeedInit = false;
-			uint32 containerSize = 1 + 1, idsWrapSize = (toSendCount << 1); // cons + vector size, idsWrapSize - size of "request-like" wrap for msgId vector
+			uint32 containerSize = 1 + 1; // cons + vector size
 			if (pingRequest) containerSize += pingRequest.messageSize();
 			if (ackRequest) containerSize += ackRequest.messageSize();
 			if (resendRequest) containerSize += resendRequest.messageSize();
@@ -767,27 +761,26 @@ void Connection::tryToSend() {
 			QWriteLocker locker2(_sessionData->haveSentMutex());
 			auto &haveSent = _sessionData->haveSentMap();
 
-			// prepare "request-like" wrap for msgId vector
-			auto haveSentIdsWrap = SerializedRequest::Prepare(idsWrapSize);
-			haveSentIdsWrap->isContainerIdsWrap = true;
-			haveSentIdsWrap->resize(haveSentIdsWrap->size() + idsWrapSize);
-			auto haveSentArr = (mtpMsgId*)(haveSentIdsWrap->data() + 8);
+			// prepare sent container
+			auto sentIdsWrap = SentContainer();
+			sentIdsWrap.sent = crl::now();
+			sentIdsWrap.messages.reserve(toSendCount);
 
 			if (bindDcKeyRequest) {
 				_bindMsgId = placeToContainer(
+					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					false,
-					haveSentArr,
 					bindDcKeyRequest);
 				needAnyResponse = true;
 			}
 			if (pingRequest) {
 				_pingMsgId = placeToContainer(
+					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
-					haveSentArr,
 					pingRequest);
 				needAnyResponse = true;
 			}
@@ -799,10 +792,10 @@ void Connection::tryToSend() {
 					request,
 					bigMsgId,
 					forceNewMsgId);
+				sentIdsWrap.messages.push_back(msgId);
 				if (msgId >= bigMsgId) {
 					bigMsgId = base::unixtime::mtproto_msg_id();
 				}
-				*(haveSentArr++) = msgId;
 				bool added = false;
 				if (request->requestId) {
 					if (request.needAck()) {
@@ -838,22 +831,46 @@ void Connection::tryToSend() {
 				}
 			}
 			if (stateRequest) {
-				const auto msgId = placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, stateRequest);
+				const auto msgId = placeToContainer(
+					sentIdsWrap,
+					toSendRequest,
+					bigMsgId,
+					forceNewMsgId,
+					stateRequest);
 				Assert(!haveSent.contains(msgId));
 				haveSent.emplace(msgId, stateRequest);
 			}
-			if (resendRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, resendRequest);
-			if (ackRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, ackRequest);
-			if (httpWaitRequest) placeToContainer(toSendRequest, bigMsgId, forceNewMsgId, haveSentArr, httpWaitRequest);
+			if (resendRequest) {
+				placeToContainer(
+					sentIdsWrap,
+					toSendRequest,
+					bigMsgId,
+					forceNewMsgId,
+					resendRequest);
+			}
+			if (ackRequest) {
+				placeToContainer(
+					sentIdsWrap,
+					toSendRequest,
+					bigMsgId,
+					forceNewMsgId,
+					ackRequest);
+			}
+			if (httpWaitRequest) {
+				placeToContainer(
+					sentIdsWrap,
+					toSendRequest,
+					bigMsgId,
+					forceNewMsgId,
+					httpWaitRequest);
+			}
+			toSend.clear();
 
 			const auto containerMsgId = prepareToSend(
 				toSendRequest,
 				bigMsgId,
 				forceNewMsgId);
-			*(mtpMsgId*)(haveSentIdsWrap->data() + 4) = containerMsgId;
-			Assert(!haveSent.contains(containerMsgId));
-			haveSent.emplace(containerMsgId, haveSentIdsWrap);
-			toSend.clear();
+			_sentContainers.emplace(containerMsgId, std::move(sentIdsWrap));
 		}
 	}
 	sendSecureRequest(std::move(toSendRequest), needAnyResponse);
@@ -1452,29 +1469,15 @@ Connection::HandleResult Connection::handleOneReceived(
 				|| (errorCode == 64); // bad container
 			if (errorCode == 64) { // bad container!
 				if (Logs::DebugEnabled()) {
-					SerializedRequest request;
-					{
-						QWriteLocker locker(_sessionData->haveSentMutex());
-						auto &haveSent = _sessionData->haveSentMap();
-
-						const auto i = haveSent.find(resendId);
-						if (i == haveSent.end()) {
-							LOG(("Message Error: Container not found!"));
-						} else {
-							request = i->second;
-						}
-					}
-					if (request) {
-						if (request.isSentContainer()) {
-							QStringList lst;
-							const auto ids = (const mtpMsgId*)(request->constData() + 8);
-							for (uint32 i = 0, l = (request->size() - 8) >> 1; i < l; ++i) {
-								lst.push_back(QString::number(ids[i]));
-							}
-							LOG(("Message Info: bad container received! messages: %1").arg(lst.join(',')));
-						} else {
-							LOG(("Message Error: bad container received, but request is not a container!"));
+					const auto i = _sentContainers.find(resendId);
+					if (i == _sentContainers.end()) {
+						LOG(("Message Error: Container not found!"));
+					} else {
+						auto idsList = QStringList();
+						for (const auto innerMsgId : i->second.messages) {
+							idsList.push_back(QString::number(innerMsgId));
 						}
+						LOG(("Message Info: bad container received! messages: %1").arg(idsList.join(',')));
 					}
 				}
 			}
@@ -1613,7 +1616,7 @@ Connection::HandleResult Connection::handleOneReceived(
 		} else {
 			MTPMsgResendReq request;
 			if (!request.read(rFrom, rEnd)) {
-				LOG(("Message Error: could not parse sent msgs_state_req"));
+				LOG(("Message Error: could not parse sent msgs_resend_req"));
 				return HandleResult::ParseError;
 			}
 			handleMsgsStates(request.c_msg_resend_req().vmsg_ids().v, states, toAck);
@@ -1962,64 +1965,58 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 		QWriteLocker locker2(_sessionData->haveSentMutex());
 		auto &haveSent = _sessionData->haveSentMap();
 
-		for (uint32 i = 0; i < idsCount; ++i) {
-			mtpMsgId msgId = ids[i].v;
-			const auto req = haveSent.find(msgId);
-			if (req != haveSent.end()) {
-				if (req->second.isSentContainer()) {
-					DEBUG_LOG(("Message Info: container ack received, msgId %1").arg(ids[i].v));
-					uint32 inContCount = (req->second->size() - 8) / 2;
-					const mtpMsgId *inContId = (const mtpMsgId *)(req->second->constData() + 8);
-					toAckMore.reserve(toAckMore.size() + inContCount);
-					for (uint32 j = 0; j < inContCount; ++j) {
-						toAckMore.push_back(MTP_long(*(inContId++)));
-					}
-					haveSent.erase(req);
-				} else {
-					const auto requestId = req->second->requestId;
-					bool moveToAcked = byResponse;
-					if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
-						moveToAcked = !_instance->hasCallbacks(requestId);
-					}
-					if (moveToAcked) {
-						_ackedIds.emplace(msgId, requestId);
-						haveSent.erase(req);
-					} else {
-						DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(requestId));
-					}
-				}
-			} else {
-				DEBUG_LOG(("Message Info: msgId %1 was not found in recent sent, while acking requests, searching in resend...").arg(msgId));
-				const auto reqIt = _resendingIds.find(msgId);
-				if (reqIt != _resendingIds.end()) {
-					const auto reqId = reqIt->second;
-					bool moveToAcked = byResponse;
-					if (!moveToAcked) { // ignore ACK, if we need a response (if we have a handler)
-						moveToAcked = !_instance->hasCallbacks(reqId);
-					}
-					if (moveToAcked) {
-						QWriteLocker locker4(_sessionData->toSendMutex());
-						auto &toSend = _sessionData->toSendMap();
-						const auto req = toSend.find(reqId);
-						if (req != toSend.cend()) {
-							_ackedIds.emplace(msgId, req->second->requestId);
-							if (req->second->requestId != reqId) {
-								DEBUG_LOG(("Message Error: for msgId %1 found resent request, requestId %2, contains requestId %3").arg(msgId).arg(reqId).arg(req->second->requestId));
-							} else {
-								DEBUG_LOG(("Message Info: acked msgId %1 that was prepared to resend, requestId %2").arg(msgId).arg(reqId));
-							}
-							toSend.erase(req);
-						} else {
-							DEBUG_LOG(("Message Info: msgId %1 was found in recent resent, requestId %2 was not found in prepared to send").arg(msgId));
-						}
-						_resendingIds.erase(reqIt);
-					} else {
-						DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(reqId));
-					}
-				} else {
-					DEBUG_LOG(("Message Info: msgId %1 was not found in recent resent either").arg(msgId));
+		for (const auto &wrappedMsgId : ids) {
+			const auto msgId = wrappedMsgId.v;
+			if (const auto i = _sentContainers.find(msgId); i != end(_sentContainers)) {
+				DEBUG_LOG(("Message Info: container ack received, msgId %1").arg(msgId));
+				const auto &list = i->second.messages;
+				toAckMore.reserve(toAckMore.size() + list.size());
+				for (const auto msgId : list) {
+					toAckMore.push_back(MTP_long(msgId));
 				}
+				_sentContainers.erase(i);
+				continue;
 			}
+			if (const auto i = haveSent.find(msgId); i != end(haveSent)) {
+				const auto requestId = i->second->requestId;
+
+				if (!byResponse && _instance->hasCallbacks(requestId)) {
+					DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(requestId));
+					continue;
+				}
+				haveSent.erase(i);
+
+				_ackedIds.emplace(msgId, requestId);
+				continue;
+			}
+			DEBUG_LOG(("Message Info: msgId %1 was not found in recent sent, while acking requests, searching in resend...").arg(msgId));
+			if (const auto i = _resendingIds.find(msgId); i != end(_resendingIds)) {
+				const auto requestId = i->second;
+
+				if (!byResponse && _instance->hasCallbacks(requestId)) {
+					DEBUG_LOG(("Message Info: ignoring ACK for msgId %1 because request %2 requires a response").arg(msgId).arg(requestId));
+					continue;
+				}
+				_resendingIds.erase(i);
+
+				QWriteLocker locker4(_sessionData->toSendMutex());
+				auto &toSend = _sessionData->toSendMap();
+				const auto j = toSend.find(requestId);
+				if (j == end(toSend)) {
+					DEBUG_LOG(("Message Info: msgId %1 was found in recent resent, requestId %2 was not found in prepared to send").arg(msgId).arg(requestId));
+					continue;
+				}
+				if (j->second->requestId != requestId) {
+					DEBUG_LOG(("Message Error: for msgId %1 found resent request, requestId %2, contains requestId %3").arg(msgId).arg(requestId).arg(j->second->requestId));
+				} else {
+					DEBUG_LOG(("Message Info: acked msgId %1 that was prepared to resend, requestId %2").arg(msgId).arg(requestId));
+				}
+				toSend.erase(j);
+
+				_ackedIds.emplace(msgId, j->second->requestId);
+				continue;
+			}
+			DEBUG_LOG(("Message Info: msgId %1 was not found in recent resent either").arg(msgId));
 		}
 	}
 
@@ -2100,6 +2097,16 @@ void Connection::resend(
 		}
 	});
 
+	if (const auto i = _sentContainers.find(msgId); i != end(_sentContainers)) {
+		DEBUG_LOG(("Message Info: resending container, msgId %1").arg(msgId));
+		const auto ids = std::move(i->second.messages);
+		_sentContainers.erase(i);
+
+		for (const auto innerMsgId : ids) {
+			resend(innerMsgId, -1, true);
+		}
+		return;
+	}
 	auto lock = QWriteLocker(_sessionData->haveSentMutex());
 	auto &haveSent = _sessionData->haveSentMap();
 	auto i = haveSent.find(msgId);
@@ -2110,14 +2117,7 @@ void Connection::resend(
 	haveSent.erase(i);
 	lock.unlock();
 
-	// For container just resend all messages we can.
-	if (request.isSentContainer()) {
-		DEBUG_LOG(("Message Info: resending container from haveSent, msgId %1").arg(msgId));
-		const mtpMsgId *ids = (const mtpMsgId *)(request->constData() + 8);
-		for (uint32 i = 0, l = (request->size() - 8) >> 1; i < l; ++i) {
-			resend(ids[i], -1, true);
-		}
-	} else if (!request.isStateRequest()) {
+	if (!request.isStateRequest()) {
 		request->lastSentTime = crl::now();
 		request->forceSendInContainer = forceContainer;
 		_resendingIds.emplace(msgId, request->requestId);
@@ -2135,7 +2135,7 @@ void Connection::resendAll() {
 	const auto &haveSent = _sessionData->haveSentMap();
 	toResend.reserve(haveSent.size());
 	for (const auto &[msgId, request] : haveSent) {
-		if (!request.isSentContainer() && !request.isStateRequest()) {
+		if (!request.isStateRequest()) {
 			toResend.push_back(msgId);
 		}
 	}
@@ -2549,6 +2549,16 @@ mtpRequestId Connection::wasSent(mtpMsgId msgId) const {
 	if (msgId == _pingMsgId || msgId == _bindMsgId) {
 		return mtpRequestId(0xFFFFFFFF);
 	}
+	if (const auto i = _resendingIds.find(msgId); i != end(_resendingIds)) {
+		return i->second;
+	}
+	if (const auto i = _ackedIds.find(msgId); i != end(_ackedIds)) {
+		return i->second;
+	}
+	if (const auto i = _sentContainers.find(msgId); i != end(_sentContainers)) {
+		return mtpRequestId(0xFFFFFFFF);
+	}
+
 	{
 		QReadLocker locker(_sessionData->haveSentMutex());
 		const auto &haveSent = _sessionData->haveSentMap();
@@ -2559,12 +2569,6 @@ mtpRequestId Connection::wasSent(mtpMsgId msgId) const {
 				: mtpRequestId(0xFFFFFFFF);
 		}
 	}
-	if (const auto i = _resendingIds.find(msgId); i != end(_resendingIds)) {
-		return i->second;
-	}
-	if (const auto i = _ackedIds.find(msgId); i != end(_ackedIds)) {
-		return i->second;
-	}
 	return 0;
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index bd2384b52..036a90cfd 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -61,7 +61,10 @@ private:
 		ConnectionPointer data;
 		int priority = 0;
 	};
-
+	struct SentContainer {
+		crl::time sent = 0;
+		std::vector<mtpMsgId> messages;
+	};
 	enum class HandleResult {
 		Success,
 		Ignored,
@@ -100,12 +103,13 @@ private:
 	[[nodiscard]] int16 getProtocolDcId() const;
 
 	void checkSentRequests();
+	void clearOldContainers();
 
 	mtpMsgId placeToContainer(
+		SentContainer &sentIdsWrap,
 		details::SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
-		mtpMsgId *&haveSentArr,
 		details::SerializedRequest &req);
 	mtpMsgId prepareToSend(
 		details::SerializedRequest &request,
@@ -216,6 +220,7 @@ private:
 	details::ReceivedIdsManager _receivedMessageIds;
 	base::flat_map<mtpMsgId, mtpRequestId> _resendingIds;
 	base::flat_map<mtpMsgId, mtpRequestId> _ackedIds;
+	base::flat_map<mtpMsgId, SentContainer> _sentContainers;
 
 	std::unique_ptr<details::BoundKeyCreator> _keyCreator;
 	mtpMsgId _bindMsgId = 0;
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
index 032957d40..437b79c9e 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
@@ -124,12 +124,6 @@ uint32 SerializedRequest::messageSize() const {
 	return kMessageIdInts + kSeqNoInts + kMessageLengthInts + ints;
 }
 
-bool SerializedRequest::isSentContainer() const {
-	Expects(_data != nullptr);
-
-	return _data->isContainerIdsWrap;
-}
-
 bool SerializedRequest::isStateRequest() const {
 	Expects(_data != nullptr);
 	Expects(_data->size() > kMessageBodyPosition);
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
index 08e13380e..5da84f4b3 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
@@ -67,8 +67,6 @@ public:
 	void addPadding(bool extended, bool old);
 	[[nodiscard]] uint32 messageSize() const;
 
-	// "request-like" wrap for msgIds vector
-	[[nodiscard]] bool isSentContainer() const;
 	[[nodiscard]] bool isStateRequest() const;
 	[[nodiscard]] bool needAck() const;
 
@@ -94,7 +92,6 @@ public:
 	mtpRequestId requestId = 0;
 	bool needsLayer = false;
 	bool forceSendInContainer = false;
-	bool isContainerIdsWrap = false;
 
 };
 

From 3b703d726286f25a15a290c9966f7ce120e56e93 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 13:49:33 +0300
Subject: [PATCH 71/91] Keep in sent container only important msgIds.

---
 Telegram/SourceFiles/mtproto/connection.cpp | 40 ++++++++++++---------
 Telegram/SourceFiles/mtproto/connection.h   |  1 -
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index 7a800c524..d180ebba6 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -249,20 +249,31 @@ void Connection::checkSentRequests() {
 }
 
 void Connection::clearOldContainers() {
+	auto resent = false;
 	const auto now = crl::now();
 	for (auto i = _sentContainers.begin(); i != _sentContainers.end();) {
 		if (now > i->second.sent + kSentContainerLives) {
-			DEBUG_LOG(("MTP Info: Removing old container %1, "
+			DEBUG_LOG(("MTP Info: Removing old container with resending %1, "
 				"sent: %2, now: %3, current unixtime: %4"
 				).arg(i->first
 				).arg(i->second.sent
 				).arg(now
 				).arg(base::unixtime::now()));
+
+			const auto ids = std::move(i->second.messages);
 			i = _sentContainers.erase(i);
+
+			resent = resent || !ids.empty();
+			for (const auto innerMsgId : ids) {
+				resend(innerMsgId, -1, true);
+			}
 		} else {
 			++i;
 		}
 	}
+	if (resent) {
+		_sessionData->queueNeedToResumeAndSend();
+	}
 }
 
 void Connection::destroyAllConnections() {
@@ -464,7 +475,6 @@ mtpMsgId Connection::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
 }
 
 mtpMsgId Connection::placeToContainer(
-		SentContainer &sentIdsWrap,
 		SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
@@ -473,7 +483,6 @@ mtpMsgId Connection::placeToContainer(
 	if (msgId >= bigMsgId) {
 		bigMsgId = base::unixtime::mtproto_msg_id();
 	}
-	sentIdsWrap.messages.push_back(msgId);
 
 	uint32 from = toSendRequest->size(), len = req.messageSize();
 	toSendRequest->resize(from + len);
@@ -554,6 +563,8 @@ void Connection::tryToSend() {
 			resendRequest = SerializedRequest::Serialize(MTPMsgResendReq(
 				MTP_msg_resend_req(MTP_vector<MTPlong>(
 					base::take(_resendRequestData)))));
+			// Add to haveSent / _ackedIds, but don't add to requestMap.
+			resendRequest->requestId = GetNextRequestId();
 		}
 		if (!_stateRequestData.empty()) {
 			auto ids = QVector<MTPlong>();
@@ -768,7 +779,6 @@ void Connection::tryToSend() {
 
 			if (bindDcKeyRequest) {
 				_bindMsgId = placeToContainer(
-					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					false,
@@ -777,22 +787,17 @@ void Connection::tryToSend() {
 			}
 			if (pingRequest) {
 				_pingMsgId = placeToContainer(
-					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
 					pingRequest);
 				needAnyResponse = true;
 			}
-			if (resendRequest || stateRequest) {
-				needAnyResponse = true;
-			}
 			for (auto &[requestId, request] : toSend) {
 				const auto msgId = prepareToSend(
 					request,
 					bigMsgId,
 					forceNewMsgId);
-				sentIdsWrap.messages.push_back(msgId);
 				if (msgId >= bigMsgId) {
 					bigMsgId = base::unixtime::mtproto_msg_id();
 				}
@@ -816,9 +821,10 @@ void Connection::tryToSend() {
 							*(toSendRequest->data() + reqNeedsLayer + 3) += initSize;
 							added = true;
 						}
+
 						Assert(!haveSent.contains(msgId));
 						haveSent.emplace(msgId, request);
-
+						sentIdsWrap.messages.push_back(msgId);
 						needAnyResponse = true;
 					} else {
 						_ackedIds.emplace(msgId, request->requestId);
@@ -832,25 +838,28 @@ void Connection::tryToSend() {
 			}
 			if (stateRequest) {
 				const auto msgId = placeToContainer(
-					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
 					stateRequest);
 				Assert(!haveSent.contains(msgId));
 				haveSent.emplace(msgId, stateRequest);
+				sentIdsWrap.messages.push_back(msgId);
+				needAnyResponse = true;
 			}
 			if (resendRequest) {
-				placeToContainer(
-					sentIdsWrap,
+				const auto msgId = placeToContainer(
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
 					resendRequest);
+				Assert(!haveSent.contains(msgId));
+				haveSent.emplace(msgId, resendRequest);
+				sentIdsWrap.messages.push_back(msgId);
+				needAnyResponse = true;
 			}
 			if (ackRequest) {
 				placeToContainer(
-					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
@@ -858,7 +867,6 @@ void Connection::tryToSend() {
 			}
 			if (httpWaitRequest) {
 				placeToContainer(
-					sentIdsWrap,
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
@@ -1959,7 +1967,6 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 
 	DEBUG_LOG(("Message Info: requests acked, ids %1").arg(LogIdsVector(ids)));
 
-	auto clearedBecauseTooOld = std::vector<RPCCallbackClear>();
 	QVector<MTPlong> toAckMore;
 	{
 		QWriteLocker locker2(_sessionData->haveSentMutex());
@@ -2023,7 +2030,6 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 	auto ackedCount = _ackedIds.size();
 	if (ackedCount > kIdsBufferSize) {
 		DEBUG_LOG(("Message Info: removing some old acked sent msgIds %1").arg(ackedCount - kIdsBufferSize));
-		clearedBecauseTooOld.reserve(ackedCount - kIdsBufferSize);
 		while (ackedCount-- > kIdsBufferSize) {
 			_ackedIds.erase(_ackedIds.begin());
 		}
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 036a90cfd..706919b4b 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -106,7 +106,6 @@ private:
 	void clearOldContainers();
 
 	mtpMsgId placeToContainer(
-		SentContainer &sentIdsWrap,
 		details::SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,

From 718de09aa6b2059c7042f16f3feff3ec0645d554 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 14:34:14 +0300
Subject: [PATCH 72/91] Handle state / resend requests separately.

---
 Telegram/SourceFiles/mtproto/connection.cpp   | 142 ++++++++----------
 Telegram/SourceFiles/mtproto/connection.h     |   3 +-
 .../details/mtproto_serialized_request.cpp    |   8 -
 .../details/mtproto_serialized_request.h      |   1 -
 4 files changed, 67 insertions(+), 87 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/connection.cpp
index d180ebba6..f8b4a9bb5 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/connection.cpp
@@ -226,9 +226,7 @@ void Connection::checkSentRequests() {
 		const auto now = crl::now();
 		const auto checkAfter = kCheckSentRequestTimeout;
 		for (const auto &[msgId, request] : haveSent) {
-			if (request.isStateRequest()) {
-				continue;
-			} else if (request->lastSentTime + checkAfter < now) {
+			if (request->lastSentTime + checkAfter < now) {
 				// Need to check state.
 				request->lastSentTime = now;
 				if (_bindMsgId) {
@@ -563,8 +561,6 @@ void Connection::tryToSend() {
 			resendRequest = SerializedRequest::Serialize(MTPMsgResendReq(
 				MTP_msg_resend_req(MTP_vector<MTPlong>(
 					base::take(_resendRequestData)))));
-			// Add to haveSent / _ackedIds, but don't add to requestMap.
-			resendRequest->requestId = GetNextRequestId();
 		}
 		if (!_stateRequestData.empty()) {
 			auto ids = QVector<MTPlong>();
@@ -574,8 +570,6 @@ void Connection::tryToSend() {
 			}
 			stateRequest = SerializedRequest::Serialize(MTPMsgsStateReq(
 				MTP_msgs_state_req(MTP_vector<MTPlong>(ids))));
-			// Add to haveSent / _ackedIds, but don't add to requestMap.
-			stateRequest->requestId = GetNextRequestId();
 		}
 		if (_connection->usingHttpWait()) {
 			httpWaitRequest = SerializedRequest::Serialize(MTPHttpWait(
@@ -694,7 +688,10 @@ void Connection::tryToSend() {
 			} else if (pingRequest) {
 				_pingMsgId = msgId;
 				needAnyResponse = true;
-			} else if (resendRequest || stateRequest) {
+			} else if (stateRequest || resendRequest) {
+				_stateAndResendRequests.emplace(
+					msgId,
+					stateRequest ? stateRequest : resendRequest);
 				needAnyResponse = true;
 			}
 
@@ -793,6 +790,7 @@ void Connection::tryToSend() {
 					pingRequest);
 				needAnyResponse = true;
 			}
+
 			for (auto &[requestId, request] : toSend) {
 				const auto msgId = prepareToSend(
 					request,
@@ -836,15 +834,15 @@ void Connection::tryToSend() {
 					memcpy(toSendRequest->data() + from, request->constData() + 4, len * sizeof(mtpPrime));
 				}
 			}
+			toSend.clear();
+
 			if (stateRequest) {
 				const auto msgId = placeToContainer(
 					toSendRequest,
 					bigMsgId,
 					forceNewMsgId,
 					stateRequest);
-				Assert(!haveSent.contains(msgId));
-				haveSent.emplace(msgId, stateRequest);
-				sentIdsWrap.messages.push_back(msgId);
+				_stateAndResendRequests.emplace(msgId, stateRequest);
 				needAnyResponse = true;
 			}
 			if (resendRequest) {
@@ -853,9 +851,7 @@ void Connection::tryToSend() {
 					bigMsgId,
 					forceNewMsgId,
 					resendRequest);
-				Assert(!haveSent.contains(msgId));
-				haveSent.emplace(msgId, resendRequest);
-				sentIdsWrap.messages.push_back(msgId);
+				_stateAndResendRequests.emplace(msgId, resendRequest);
 				needAnyResponse = true;
 			}
 			if (ackRequest) {
@@ -872,7 +868,6 @@ void Connection::tryToSend() {
 					forceNewMsgId,
 					httpWaitRequest);
 			}
-			toSend.clear();
 
 			const auto containerMsgId = prepareToSend(
 				toSendRequest,
@@ -1585,52 +1580,44 @@ Connection::HandleResult Connection::handleOneReceived(
 		auto &states = data.vinfo().v;
 
 		DEBUG_LOG(("Message Info: msg state received, msgId %1, reqMsgId: %2, HEX states %3").arg(msgId).arg(reqMsgId).arg(Logs::mb(states.data(), states.length()).str()));
-		SerializedRequest requestBuffer;
-		{ // find this request in session-shared sent requests map
-			QReadLocker locker(_sessionData->haveSentMutex());
-			const auto &haveSent = _sessionData->haveSentMap();
-			const auto replyTo = haveSent.find(reqMsgId);
-			if (replyTo == haveSent.end()) { // do not look in toResend, because we do not resend msgs_state_req requests
-				DEBUG_LOG(("Message Error: such message was not sent recently %1").arg(reqMsgId));
-				return (badTime ? HandleResult::Ignored : HandleResult::Success);
-			}
-			if (badTime) {
-				if (serverSalt) {
-					_sessionSalt = serverSalt; // requestsFixTimeSalt with no lookup
-				}
-				base::unixtime::update(serverTime, true);
-
-				DEBUG_LOG(("Message Info: unixtime updated from mtpc_msgs_state_info, now %1").arg(serverTime));
-
-				badTime = false;
-			}
-			requestBuffer = replyTo->second;
+		const auto i = _stateAndResendRequests.find(reqMsgId);
+		if (i == _stateAndResendRequests.end()) {
+			DEBUG_LOG(("Message Error: such message was not sent recently %1").arg(reqMsgId));
+			return (badTime ? HandleResult::Ignored : HandleResult::Success);
 		}
-		QVector<MTPlong> toAckReq(1, MTP_long(reqMsgId)), toAck;
-		requestsAcked(toAck, true);
+		if (badTime) {
+			if (serverSalt) {
+				_sessionSalt = serverSalt; // requestsFixTimeSalt with no lookup
+			}
+			base::unixtime::update(serverTime, true);
 
-		if (requestBuffer->size() < 9) {
-			LOG(("Message Error: bad request %1 found in requestMap, size: %2").arg(reqMsgId).arg(requestBuffer->size()));
-			return HandleResult::RestartConnection;
+			DEBUG_LOG(("Message Info: unixtime updated from mtpc_msgs_state_info, now %1").arg(serverTime));
+
+			badTime = false;
 		}
-		const mtpPrime *rFrom = requestBuffer->constData() + 8, *rEnd = requestBuffer->constData() + requestBuffer->size();
+		const auto originalRequest = i->second;
+		Assert(originalRequest->size() > 8);
+
+		requestsAcked(QVector<MTPlong>(1, MTP_long(reqMsgId)), true);
+
+		auto rFrom = originalRequest->constData() + 8;
+		const auto rEnd = originalRequest->constData() + originalRequest->size();
+		auto toAck = QVector<MTPlong>();
 		if (mtpTypeId(*rFrom) == mtpc_msgs_state_req) {
 			MTPMsgsStateReq request;
 			if (!request.read(rFrom, rEnd)) {
 				LOG(("Message Error: could not parse sent msgs_state_req"));
 				return HandleResult::ParseError;
 			}
-			handleMsgsStates(request.c_msgs_state_req().vmsg_ids().v, states, toAck);
+			handleMsgsStates(request.c_msgs_state_req().vmsg_ids().v, states);
 		} else {
 			MTPMsgResendReq request;
 			if (!request.read(rFrom, rEnd)) {
 				LOG(("Message Error: could not parse sent msgs_resend_req"));
 				return HandleResult::ParseError;
 			}
-			handleMsgsStates(request.c_msg_resend_req().vmsg_ids().v, states, toAck);
+			handleMsgsStates(request.c_msg_resend_req().vmsg_ids().v, states);
 		}
-
-		requestsAcked(toAck);
 	} return HandleResult::Success;
 
 	case mtpc_msgs_all_info: {
@@ -1647,12 +1634,8 @@ Connection::HandleResult Connection::handleOneReceived(
 		auto &ids = data.vmsg_ids().v;
 		auto &states = data.vinfo().v;
 
-		QVector<MTPlong> toAck;
-
 		DEBUG_LOG(("Message Info: msgs all info received, msgId %1, reqMsgIds: %2, states %3").arg(msgId).arg(LogIdsVector(ids)).arg(Logs::mb(states.data(), states.length()).str()));
-		handleMsgsStates(ids, states, toAck);
-
-		requestsAcked(toAck);
+		handleMsgsStates(ids, states);
 	} return HandleResult::Success;
 
 	case mtpc_msg_detailed_info: {
@@ -1984,6 +1967,10 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 				_sentContainers.erase(i);
 				continue;
 			}
+			if (const auto i = _stateAndResendRequests.find(msgId); i != end(_stateAndResendRequests)) {
+				_stateAndResendRequests.erase(i);
+				continue;
+			}
 			if (const auto i = haveSent.find(msgId); i != end(haveSent)) {
 				const auto requestId = i->second->requestId;
 
@@ -2040,21 +2027,22 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 	}
 }
 
-void Connection::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked) {
-	uint32 idsCount = ids.size();
+void Connection::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states) {
+	const auto idsCount = ids.size();
 	if (!idsCount) {
 		DEBUG_LOG(("Message Info: void ids vector in handleMsgsStates()"));
 		return;
 	}
-	if (states.size() < idsCount) {
+	if (states.size() != idsCount) {
 		LOG(("Message Error: got less states than required ids count."));
 		return;
 	}
 
-	acked.reserve(acked.size() + idsCount);
-	for (uint32 i = 0, count = idsCount; i < count; ++i) {
-		char state = states[i];
-		uint64 requestMsgId = ids[i].v;
+	auto acked = QVector<MTPlong>();
+	acked.reserve(idsCount);
+	for (auto i = 0; i != idsCount; ++i) {
+		const auto state = states[i];
+		const auto requestMsgId = ids[i].v;
 		{
 			QReadLocker locker(_sessionData->haveSentMutex());
 			if (!_sessionData->haveSentMap().contains(requestMsgId)) {
@@ -2081,6 +2069,7 @@ void Connection::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray
 			acked.push_back(MTP_long(requestMsgId));
 		}
 	}
+	requestsAcked(acked);
 }
 
 void Connection::clearSpecialMsgId(mtpMsgId msgId) {
@@ -2123,33 +2112,32 @@ void Connection::resend(
 	haveSent.erase(i);
 	lock.unlock();
 
-	if (!request.isStateRequest()) {
-		request->lastSentTime = crl::now();
-		request->forceSendInContainer = forceContainer;
-		_resendingIds.emplace(msgId, request->requestId);
-		{
-			QWriteLocker locker(_sessionData->toSendMutex());
-			_sessionData->toSendMap().emplace(request->requestId, request);
-		}
+	request->lastSentTime = crl::now();
+	request->forceSendInContainer = forceContainer;
+	_resendingIds.emplace(msgId, request->requestId);
+	{
+		QWriteLocker locker(_sessionData->toSendMutex());
+		_sessionData->toSendMap().emplace(request->requestId, request);
 	}
 }
 
 void Connection::resendAll() {
-	auto toResend = std::vector<mtpMsgId>();
-
-	auto lock = QReadLocker(_sessionData->haveSentMutex());
-	const auto &haveSent = _sessionData->haveSentMap();
-	toResend.reserve(haveSent.size());
-	for (const auto &[msgId, request] : haveSent) {
-		if (!request.isStateRequest()) {
-			toResend.push_back(msgId);
+	auto lock = QWriteLocker(_sessionData->haveSentMutex());
+	auto haveSent = base::take(_sessionData->haveSentMap());
+	lock.unlock();
+	{
+		auto lock = QWriteLocker(_sessionData->toSendMutex());
+		auto &toSend = _sessionData->toSendMap();
+		const auto now = crl::now();
+		for (auto &[msgId, request] : haveSent) {
+			const auto requestId = request->requestId;
+			request->lastSentTime = now;
+			request->forceSendInContainer = true;
+			_resendingIds.emplace(msgId, requestId);
+			toSend.emplace(requestId, std::move(request));
 		}
 	}
-	lock.unlock();
 
-	for (const auto msgId : toResend) {
-		resend(msgId, -1, true);
-	}
 	_sessionData->queueSendAnything();
 }
 
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/connection.h
index 706919b4b..67b898f48 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/connection.h
@@ -128,7 +128,7 @@ private:
 		mtpMsgId requestMsgId,
 		const mtpBuffer &response);
 	mtpBuffer ungzip(const mtpPrime *from, const mtpPrime *end) const;
-	void handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states, QVector<MTPlong> &acked);
+	void handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states);
 
 	// _sessionDataMutex must be locked for read.
 	bool setState(int state, int ifState = kUpdateStateAlways);
@@ -219,6 +219,7 @@ private:
 	details::ReceivedIdsManager _receivedMessageIds;
 	base::flat_map<mtpMsgId, mtpRequestId> _resendingIds;
 	base::flat_map<mtpMsgId, mtpRequestId> _ackedIds;
+	base::flat_map<mtpMsgId, details::SerializedRequest> _stateAndResendRequests;
 	base::flat_map<mtpMsgId, SentContainer> _sentContainers;
 
 	std::unique_ptr<details::BoundKeyCreator> _keyCreator;
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
index 437b79c9e..5b04acafb 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.cpp
@@ -124,14 +124,6 @@ uint32 SerializedRequest::messageSize() const {
 	return kMessageIdInts + kSeqNoInts + kMessageLengthInts + ints;
 }
 
-bool SerializedRequest::isStateRequest() const {
-	Expects(_data != nullptr);
-	Expects(_data->size() > kMessageBodyPosition);
-
-	const auto type = mtpTypeId((*_data)[kMessageBodyPosition]);
-	return (type == mtpc_msgs_state_req);
-}
-
 bool SerializedRequest::needAck() const {
 	Expects(_data != nullptr);
 	Expects(_data->size() > kMessageBodyPosition);
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
index 5da84f4b3..61dd8e6c7 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
@@ -67,7 +67,6 @@ public:
 	void addPadding(bool extended, bool old);
 	[[nodiscard]] uint32 messageSize() const;
 
-	[[nodiscard]] bool isStateRequest() const;
 	[[nodiscard]] bool needAck() const;
 
 	using ResponseType = void; // don't know real response type =(

From 91f50e8bdc545f50cb414a08b3c74159c621dfc4 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 16:10:19 +0300
Subject: [PATCH 73/91] Move some more code to lib_mtproto.

---
 Telegram/SourceFiles/boxes/connection_box.cpp |   4 +-
 Telegram/SourceFiles/boxes/connection_box.h   |   2 +-
 .../codegen/scheme/codegen_scheme.py          |   2 +-
 Telegram/SourceFiles/core/application.cpp     |   4 +-
 Telegram/SourceFiles/export/export_api_wrap.h |   2 +-
 Telegram/SourceFiles/facades.h                |   1 -
 .../SourceFiles/mtproto/config_loader.cpp     |   6 +-
 Telegram/SourceFiles/mtproto/config_loader.h  |   7 +-
 .../mtproto/connection_abstract.cpp           |   4 +-
 .../SourceFiles/mtproto/connection_abstract.h |   4 +-
 .../SourceFiles/mtproto/connection_http.cpp   |   4 +-
 .../SourceFiles/mtproto/connection_http.h     |   4 +-
 .../mtproto/connection_resolving.cpp          |   4 +-
 .../mtproto/connection_resolving.h            |   4 +-
 .../SourceFiles/mtproto/connection_tcp.cpp    |   6 +-
 Telegram/SourceFiles/mtproto/connection_tcp.h |   4 +-
 Telegram/SourceFiles/mtproto/dc_options.cpp   |  20 +-
 Telegram/SourceFiles/mtproto/dc_options.h     |  11 +-
 .../{ => details}/mtproto_abstract_socket.cpp |  12 +-
 .../{ => details}/mtproto_abstract_socket.h   |   6 +-
 .../details/mtproto_dc_key_creator.cpp        |   1 +
 .../mtproto/details/mtproto_dc_key_creator.h  |   2 -
 .../mtproto_dcenter.cpp}                      |   7 +-
 .../{dcenter.h => details/mtproto_dcenter.h}  |   6 +-
 .../details/mtproto_domain_resolver.cpp       | 362 ++++++++++++++++++
 .../mtproto/details/mtproto_domain_resolver.h | 106 +++++
 .../{ => details}/mtproto_rsa_public_key.cpp  |   8 +-
 .../{ => details}/mtproto_rsa_public_key.h    |   6 +-
 .../details/mtproto_serialized_request.h      |   8 +-
 .../{ => details}/mtproto_tcp_socket.cpp      |   8 +-
 .../{ => details}/mtproto_tcp_socket.h        |   8 +-
 .../{ => details}/mtproto_tls_socket.cpp      |  10 +-
 .../{ => details}/mtproto_tls_socket.h        |   8 +-
 Telegram/SourceFiles/mtproto/facade.cpp       |   4 +-
 Telegram/SourceFiles/mtproto/facade.h         |  22 +-
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  12 +-
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   8 +-
 ...nder.cpp => mtproto_concurrent_sender.cpp} |   4 +-
 ...t_sender.h => mtproto_concurrent_sender.h} |   3 +-
 Telegram/SourceFiles/mtproto/session.cpp      |  73 ++--
 Telegram/SourceFiles/mtproto/session.h        |  42 +-
 .../{connection.cpp => session_private.cpp}   | 196 +++++-----
 .../{connection.h => session_private.h}       |  33 +-
 .../mtproto/special_config_request.cpp        | 351 +----------------
 .../mtproto/special_config_request.h          |  86 +----
 .../passport/passport_encryption.cpp          |   4 +-
 .../SourceFiles/storage/file_download.cpp     |  17 +-
 Telegram/SourceFiles/storage/file_upload.cpp  |   6 +-
 Telegram/gyp/lib_mtproto.gyp                  |  22 +-
 Telegram/gyp/telegram/sources.txt             |   8 +-
 Telegram/lib_tl                               |   2 +-
 51 files changed, 792 insertions(+), 752 deletions(-)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_abstract_socket.cpp (73%)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_abstract_socket.h (95%)
 rename Telegram/SourceFiles/mtproto/{dcenter.cpp => details/mtproto_dcenter.cpp} (97%)
 rename Telegram/SourceFiles/mtproto/{dcenter.h => details/mtproto_dcenter.h} (95%)
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.cpp
 create mode 100644 Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.h
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_rsa_public_key.cpp (98%)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_rsa_public_key.h (94%)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_tcp_socket.cpp (97%)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_tcp_socket.h (87%)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_tls_socket.cpp (99%)
 rename Telegram/SourceFiles/mtproto/{ => details}/mtproto_tls_socket.h (92%)
 rename Telegram/SourceFiles/mtproto/{concurrent_sender.cpp => mtproto_concurrent_sender.cpp} (98%)
 rename Telegram/SourceFiles/mtproto/{concurrent_sender.h => mtproto_concurrent_sender.h} (99%)
 rename Telegram/SourceFiles/mtproto/{connection.cpp => session_private.cpp} (94%)
 rename Telegram/SourceFiles/mtproto/{connection.h => session_private.h} (89%)

diff --git a/Telegram/SourceFiles/boxes/connection_box.cpp b/Telegram/SourceFiles/boxes/connection_box.cpp
index 2b9cd94cb..f3a1a442c 100644
--- a/Telegram/SourceFiles/boxes/connection_box.cpp
+++ b/Telegram/SourceFiles/boxes/connection_box.cpp
@@ -1059,7 +1059,7 @@ void ProxiesBoxController::refreshChecker(Item &item) {
 
 	item.state = ItemState::Checking;
 	const auto setup = [&](Checker &checker, const bytes::vector &secret) {
-		checker = MTP::internal::AbstractConnection::Create(
+		checker = MTP::details::AbstractConnection::Create(
 			mtproto,
 			type,
 			QThread::currentThread(),
@@ -1107,7 +1107,7 @@ void ProxiesBoxController::refreshChecker(Item &item) {
 }
 
 void ProxiesBoxController::setupChecker(int id, const Checker &checker) {
-	using Connection = MTP::internal::AbstractConnection;
+	using Connection = MTP::details::AbstractConnection;
 	const auto pointer = checker.get();
 	pointer->connect(pointer, &Connection::connected, [=] {
 		const auto item = findById(id);
diff --git a/Telegram/SourceFiles/boxes/connection_box.h b/Telegram/SourceFiles/boxes/connection_box.h
index 21d79f9ad..fbefdacb5 100644
--- a/Telegram/SourceFiles/boxes/connection_box.h
+++ b/Telegram/SourceFiles/boxes/connection_box.h
@@ -75,7 +75,7 @@ public:
 	~ProxiesBoxController();
 
 private:
-	using Checker = MTP::internal::ConnectionPointer;
+	using Checker = MTP::details::ConnectionPointer;
 	struct Item {
 		int id = 0;
 		ProxyData data;
diff --git a/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py b/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
index 1193e6afd..ff0e91d47 100644
--- a/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
+++ b/Telegram/SourceFiles/codegen/scheme/codegen_scheme.py
@@ -14,7 +14,7 @@ from generate_tl import generate
 
 generate({
   'namespaces': {
-    'creator': 'MTP::internal',
+    'creator': 'MTP::details',
   },
   'prefixes': {
     'type': 'MTP',
diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index 04a167751..9954a1faa 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -184,9 +184,9 @@ void Application::run() {
 	style::ShortAnimationPlaying(
 	) | rpl::start_with_next([=](bool playing) {
 		if (playing) {
-			MTP::internal::pause();
+			MTP::details::pause();
 		} else {
-			MTP::internal::unpause();
+			MTP::details::unpause();
 		}
 	}, _lifetime);
 
diff --git a/Telegram/SourceFiles/export/export_api_wrap.h b/Telegram/SourceFiles/export/export_api_wrap.h
index 6f3016ab6..0e47e9be3 100644
--- a/Telegram/SourceFiles/export/export_api_wrap.h
+++ b/Telegram/SourceFiles/export/export_api_wrap.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/concurrent_sender.h"
+#include "mtproto/mtproto_concurrent_sender.h"
 
 namespace Export {
 namespace Data {
diff --git a/Telegram/SourceFiles/facades.h b/Telegram/SourceFiles/facades.h
index bfa29df18..9c4f41615 100644
--- a/Telegram/SourceFiles/facades.h
+++ b/Telegram/SourceFiles/facades.h
@@ -10,7 +10,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/type_traits.h"
 #include "base/observer.h"
 #include "base/call_delayed.h"
-#include "ui/effects/animation_value.h"
 #include "mtproto/mtproto_proxy_data.h"
 
 class History;
diff --git a/Telegram/SourceFiles/mtproto/config_loader.cpp b/Telegram/SourceFiles/mtproto/config_loader.cpp
index 3f60590a5..fc847c855 100644
--- a/Telegram/SourceFiles/mtproto/config_loader.cpp
+++ b/Telegram/SourceFiles/mtproto/config_loader.cpp
@@ -7,14 +7,14 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/config_loader.h"
 
+#include "mtproto/special_config_request.h"
 #include "mtproto/facade.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/mtp_instance.h"
-#include "mtproto/special_config_request.h"
 #include "facades.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 constexpr auto kEnumerateDcTimeout = 8000; // 8 seconds timeout for help_getConfig to work (then move to other dc)
@@ -215,5 +215,5 @@ void ConfigLoader::specialConfigLoaded(const MTPConfig &result) {
 	_instance->dcOptions()->setFromList(data.vdc_options());
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/config_loader.h b/Telegram/SourceFiles/mtproto/config_loader.h
index 476e8f164..39b7bc214 100644
--- a/Telegram/SourceFiles/mtproto/config_loader.h
+++ b/Telegram/SourceFiles/mtproto/config_loader.h
@@ -14,10 +14,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 namespace MTP {
 
-class SpecialConfigRequest;
 class Instance;
 
-namespace internal {
+namespace details {
+
+class SpecialConfigRequest;
 
 class ConfigLoader : public base::has_weak_ptr {
 public:
@@ -76,5 +77,5 @@ inline bool operator==(const ConfigLoader::SpecialEndpoint &a, const ConfigLoade
 	return (a.dcId == b.dcId) && (a.ip == b.ip) && (a.port == b.port);
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_abstract.cpp b/Telegram/SourceFiles/mtproto/connection_abstract.cpp
index 831141c29..cf2f3bdb0 100644
--- a/Telegram/SourceFiles/mtproto/connection_abstract.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_abstract.cpp
@@ -15,7 +15,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/openssl_help.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 
 ConnectionPointer::ConnectionPointer() = default;
 
@@ -194,5 +194,5 @@ uint32 AbstractConnection::extendedNotSecurePadding() const {
 		: 0;
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_abstract.h b/Telegram/SourceFiles/mtproto/connection_abstract.h
index b84ae0d08..695d83694 100644
--- a/Telegram/SourceFiles/mtproto/connection_abstract.h
+++ b/Telegram/SourceFiles/mtproto/connection_abstract.h
@@ -18,7 +18,7 @@ namespace MTP {
 
 class Instance;
 
-namespace internal {
+namespace details {
 
 struct ConnectionOptions;
 
@@ -195,5 +195,5 @@ mtpBuffer AbstractConnection::prepareNotSecurePacket(
 	return result;
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_http.cpp b/Telegram/SourceFiles/mtproto/connection_http.cpp
index f7d6a81f7..3f9d005b7 100644
--- a/Telegram/SourceFiles/mtproto/connection_http.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_http.cpp
@@ -10,7 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/qthelp_url.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 constexpr auto kForceHttpPort = 80;
@@ -246,5 +246,5 @@ QUrl HttpConnection::url() const {
 	return QUrl(pattern.arg(_address).arg(kForceHttpPort));
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_http.h b/Telegram/SourceFiles/mtproto/connection_http.h
index 57fffb875..8fb867aa5 100644
--- a/Telegram/SourceFiles/mtproto/connection_http.h
+++ b/Telegram/SourceFiles/mtproto/connection_http.h
@@ -13,7 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtNetwork/QNetworkReply>
 
 namespace MTP {
-namespace internal {
+namespace details {
 
 class HttpConnection : public AbstractConnection {
 public:
@@ -64,5 +64,5 @@ private:
 
 };
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_resolving.cpp b/Telegram/SourceFiles/mtproto/connection_resolving.cpp
index 171b8885b..7590db6a3 100644
--- a/Telegram/SourceFiles/mtproto/connection_resolving.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_resolving.cpp
@@ -10,7 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/mtp_instance.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 constexpr auto kOneConnectionTimeout = 4000;
@@ -256,5 +256,5 @@ QString ResolvingConnection::tag() const {
 	return _child ? _child->tag() : QString();
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_resolving.h b/Telegram/SourceFiles/mtproto/connection_resolving.h
index ceb9c474e..eeb137113 100644
--- a/Telegram/SourceFiles/mtproto/connection_resolving.h
+++ b/Telegram/SourceFiles/mtproto/connection_resolving.h
@@ -12,7 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/timer.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 
 class ResolvingConnection : public AbstractConnection {
 public:
@@ -67,5 +67,5 @@ private:
 
 };
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_tcp.cpp b/Telegram/SourceFiles/mtproto/connection_tcp.cpp
index f46e16c26..f195c7c44 100644
--- a/Telegram/SourceFiles/mtproto/connection_tcp.cpp
+++ b/Telegram/SourceFiles/mtproto/connection_tcp.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/connection_tcp.h"
 
-#include "mtproto/mtproto_abstract_socket.h"
+#include "mtproto/details/mtproto_abstract_socket.h"
 #include "base/bytes.h"
 #include "base/openssl_help.h"
 #include "base/qthelp_url.h"
@@ -17,7 +17,7 @@ extern "C" {
 } // extern "C"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 constexpr auto kPacketSizeMax = int(0x01000000 * sizeof(mtpPrime));
@@ -665,5 +665,5 @@ void TcpConnection::socketError() {
 
 TcpConnection::~TcpConnection() = default;
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection_tcp.h b/Telegram/SourceFiles/mtproto/connection_tcp.h
index 07134f14f..1fc5319a1 100644
--- a/Telegram/SourceFiles/mtproto/connection_tcp.h
+++ b/Telegram/SourceFiles/mtproto/connection_tcp.h
@@ -11,7 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/mtproto_auth_key.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 
 class AbstractSocket;
 
@@ -98,5 +98,5 @@ private:
 
 };
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/dc_options.cpp b/Telegram/SourceFiles/mtproto/dc_options.cpp
index 34dfd0cbe..d82d60e10 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.cpp
+++ b/Telegram/SourceFiles/mtproto/dc_options.cpp
@@ -7,13 +7,16 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/dc_options.h"
 
+#include "mtproto/details/mtproto_rsa_public_key.h"
 #include "mtproto/facade.h"
-#include "storage/serialize_common.h"
 #include "mtproto/connection_tcp.h"
+#include "storage/serialize_common.h"
 
 namespace MTP {
 namespace {
 
+using namespace details;
+
 const char *(PublicRSAKeys[]) = { "\
 -----BEGIN RSA PUBLIC KEY-----\n\
 MIIBCgKCAQEAwVACPi9w23mF3tBkdZz+zwrzKOaaQdr01vAbU4E1pvkfj4sqDsm6\n\
@@ -102,6 +105,8 @@ DcOptions::DcOptions() {
 	constructFromBuiltIn();
 }
 
+DcOptions::~DcOptions() = default;
+
 bool DcOptions::ValidateSecret(bytes::const_span secret) {
 	// See also TcpConnection::Protocol::Create.
 	return (secret.size() >= 21 && secret[0] == bytes::type(0xEE))
@@ -113,7 +118,7 @@ bool DcOptions::ValidateSecret(bytes::const_span secret) {
 void DcOptions::readBuiltInPublicKeys() {
 	for (const auto key : PublicRSAKeys) {
 		const auto keyBytes = bytes::make_span(key, strlen(key));
-		auto parsed = internal::RSAPublicKey(keyBytes);
+		auto parsed = RSAPublicKey(keyBytes);
 		if (parsed.valid()) {
 			_publicKeys.emplace(parsed.fingerprint(), std::move(parsed));
 		} else {
@@ -512,7 +517,7 @@ void DcOptions::constructFromSerialized(const QByteArray &serialized) {
 				return;
 			}
 
-			auto key = internal::RSAPublicKey(n, e);
+			auto key = RSAPublicKey(n, e);
 			if (key.valid()) {
 				_cdnPublicKeys[dcId].emplace(key.fingerprint(), std::move(key));
 			} else {
@@ -569,7 +574,7 @@ void DcOptions::setCDNConfig(const MTPDcdnConfig &config) {
 	for (const auto &key : config.vpublic_keys().v) {
 		key.match([&](const MTPDcdnPublicKey &data) {
 			const auto keyBytes = bytes::make_span(data.vpublic_key().v);
-			auto key = internal::RSAPublicKey(keyBytes);
+			auto key = RSAPublicKey(keyBytes);
 			if (key.valid()) {
 				_cdnPublicKeys[data.vdc_id().v].emplace(
 					key.fingerprint(),
@@ -590,18 +595,17 @@ bool DcOptions::hasCDNKeysForDc(DcId dcId) const {
 	return _cdnPublicKeys.find(dcId) != _cdnPublicKeys.cend();
 }
 
-internal::RSAPublicKey DcOptions::getDcRSAKey(
+RSAPublicKey DcOptions::getDcRSAKey(
 		DcId dcId,
 		const QVector<MTPlong> &fingerprints) const {
-	const auto findKey = [&](
-			const std::map<uint64, internal::RSAPublicKey> &keys) {
+	const auto findKey = [&](const std::map<uint64, RSAPublicKey> &keys) {
 		for (const auto &fingerprint : fingerprints) {
 			const auto it = keys.find(static_cast<uint64>(fingerprint.v));
 			if (it != keys.cend()) {
 				return it->second;
 			}
 		}
-		return internal::RSAPublicKey();
+		return RSAPublicKey();
 	};
 	{
 		ReadLocker lock(this);
diff --git a/Telegram/SourceFiles/mtproto/dc_options.h b/Telegram/SourceFiles/mtproto/dc_options.h
index ca0293b9c..11449d3ea 100644
--- a/Telegram/SourceFiles/mtproto/dc_options.h
+++ b/Telegram/SourceFiles/mtproto/dc_options.h
@@ -9,7 +9,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "base/observer.h"
 #include "base/bytes.h"
-#include "mtproto/mtproto_rsa_public_key.h"
 
 #include <QtCore/QReadWriteLock>
 #include <string>
@@ -18,6 +17,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <set>
 
 namespace MTP {
+namespace details {
+class RSAPublicKey;
+} // namespace details
 
 enum class DcType {
 	Regular,
@@ -52,6 +54,7 @@ public:
 	};
 
 	DcOptions();
+	~DcOptions();
 
 	[[nodiscard]] static bool ValidateSecret(bytes::const_span secret);
 
@@ -95,7 +98,7 @@ public:
 
 	void setCDNConfig(const MTPDcdnConfig &config);
 	[[nodiscard]] bool hasCDNKeysForDc(DcId dcId) const;
-	[[nodiscard]] internal::RSAPublicKey getDcRSAKey(
+	[[nodiscard]] details::RSAPublicKey getDcRSAKey(
 		DcId dcId,
 		const QVector<MTPlong> &fingerprints) const;
 
@@ -137,8 +140,8 @@ private:
 
 	std::map<DcId, std::vector<Endpoint>> _data;
 	std::set<DcId> _cdnDcIds;
-	std::map<uint64, internal::RSAPublicKey> _publicKeys;
-	std::map<DcId, std::map<uint64, internal::RSAPublicKey>> _cdnPublicKeys;
+	std::map<uint64, details::RSAPublicKey> _publicKeys;
+	std::map<DcId, std::map<uint64, details::RSAPublicKey>> _cdnPublicKeys;
 	mutable QReadWriteLock _useThroughLockers;
 
 	rpl::event_stream<DcId> _changed;
diff --git a/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_abstract_socket.cpp
similarity index 73%
rename from Telegram/SourceFiles/mtproto/mtproto_abstract_socket.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_abstract_socket.cpp
index 2f77cd144..2ad0a44a6 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_abstract_socket.cpp
@@ -5,13 +5,12 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtproto_abstract_socket.h"
+#include "mtproto/details/mtproto_abstract_socket.h"
 
-#include "mtproto/mtproto_tcp_socket.h"
-#include "mtproto/mtproto_tls_socket.h"
+#include "mtproto/details/mtproto_tcp_socket.h"
+#include "mtproto/details/mtproto_tls_socket.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 
 std::unique_ptr<AbstractSocket> AbstractSocket::Create(
 		not_null<QThread*> thread,
@@ -24,5 +23,4 @@ std::unique_ptr<AbstractSocket> AbstractSocket::Create(
 	}
 }
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.h b/Telegram/SourceFiles/mtproto/details/mtproto_abstract_socket.h
similarity index 95%
rename from Telegram/SourceFiles/mtproto/mtproto_abstract_socket.h
rename to Telegram/SourceFiles/mtproto/details/mtproto_abstract_socket.h
index 4d5c35108..61da8b5e3 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_abstract_socket.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_abstract_socket.h
@@ -10,8 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/bytes.h"
 #include "base/basic_types.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 
 class AbstractSocket : protected QObject {
 public:
@@ -62,5 +61,4 @@ protected:
 
 };
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
index 6b90e1b6a..d1da9f591 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.cpp
@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/details/mtproto_dc_key_creator.h"
 
+#include "mtproto/details/mtproto_rsa_public_key.h"
 #include "mtproto/connection_abstract.h"
 #include "mtproto/mtproto_dh_utils.h"
 #include "base/openssl_help.h"
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
index 756044444..f62bb8f41 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dc_key_creator.h
@@ -19,8 +19,6 @@ class DcOptions;
 
 namespace MTP::details {
 
-using namespace ::MTP::internal;
-
 struct DcKeyRequest {
 	TimeId temporaryExpiresIn = 0;
 	bool persistentNeeded = false;
diff --git a/Telegram/SourceFiles/mtproto/dcenter.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_dcenter.cpp
similarity index 97%
rename from Telegram/SourceFiles/mtproto/dcenter.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_dcenter.cpp
index 663d72897..43ece30f4 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dcenter.cpp
@@ -5,17 +5,16 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/dcenter.h"
+#include "mtproto/details/mtproto_dcenter.h"
 
 #include "mtproto/facade.h"
 #include "mtproto/mtproto_auth_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/mtp_instance.h"
 #include "mtproto/special_config_request.h"
-#include "storage/localstorage.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 constexpr auto kEnumerateDcTimeout = 8000; // 8 seconds timeout for help_getConfig to work (then move to other dc)
@@ -165,5 +164,5 @@ void Dcenter::releaseKeyCreationOnFail(CreatingKeyType type) {
 	_creatingKeys[IndexByType(type)] = false;
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/dcenter.h b/Telegram/SourceFiles/mtproto/details/mtproto_dcenter.h
similarity index 95%
rename from Telegram/SourceFiles/mtproto/dcenter.h
rename to Telegram/SourceFiles/mtproto/details/mtproto_dcenter.h
index 0b4636014..0418e09e4 100644
--- a/Telegram/SourceFiles/mtproto/dcenter.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_dcenter.h
@@ -7,13 +7,15 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include <QtCore/QReadWriteLock>
+
 namespace MTP {
 
 class Instance;
 class AuthKey;
 using AuthKeyPtr = std::shared_ptr<AuthKey>;
 
-namespace internal {
+namespace details {
 
 enum class TemporaryKeyType {
 	Regular,
@@ -61,5 +63,5 @@ private:
 
 };
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.cpp
new file mode 100644
index 000000000..b26308978
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.cpp
@@ -0,0 +1,362 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "mtproto/details/mtproto_domain_resolver.h"
+
+#include "base/openssl_help.h"
+#include "base/invoke_queued.h"
+#include "base/call_delayed.h"
+
+#include <QtCore/QJsonDocument>
+#include <QtCore/QJsonArray>
+#include <QtCore/QJsonObject>
+#include <range/v3/algorithm/shuffle.hpp>
+#include <range/v3/algorithm/reverse.hpp>
+#include <range/v3/algorithm/remove.hpp>
+#include <random>
+
+namespace MTP::details {
+namespace {
+
+constexpr auto kSendNextTimeout = crl::time(800);
+constexpr auto kMinTimeToLive = 10 * crl::time(1000);
+constexpr auto kMaxTimeToLive = 300 * crl::time(1000);
+
+} // namespace
+
+const std::vector<QString> &DnsDomains() {
+	static const auto kResult = std::vector<QString>{
+		"google.com",
+		"www.google.com",
+		"google.ru",
+		"www.google.ru",
+	};
+	return kResult;
+}
+
+QString GenerateDnsRandomPadding() {
+	constexpr char kValid[] = "abcdefghijklmnopqrstuvwxyz"
+		"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+
+	auto result = QString();
+	const auto count = [&] {
+		constexpr auto kMinPadding = 13;
+		constexpr auto kMaxPadding = 128;
+		while (true) {
+			const auto result = 1 + (openssl::RandomValue<uchar>() / 2);
+			Assert(result <= kMaxPadding);
+			if (result >= kMinPadding) {
+				return result;
+			}
+		}
+	}();
+	result.resize(count);
+	for (auto &ch : result) {
+		ch = kValid[openssl::RandomValue<uchar>() % (sizeof(kValid) - 1)];
+	}
+	return result;
+}
+
+QByteArray DnsUserAgent() {
+	static const auto kResult = QByteArray(
+		"Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
+		"AppleWebKit/537.36 (KHTML, like Gecko) "
+		"Chrome/77.0.3865.90 Safari/537.36");
+	return kResult;
+}
+
+std::vector<DnsEntry> ParseDnsResponse(
+		const QByteArray &bytes,
+		std::optional<int> typeRestriction) {
+	// Read and store to "result" all the data bytes from the response:
+	// { ..,
+	//   "Answer": [
+	//     { .., "data": "bytes1", "TTL": int, .. },
+	//     { .., "data": "bytes2", "TTL": int, .. }
+	//   ],
+	// .. }
+	auto error = QJsonParseError{ 0, QJsonParseError::NoError };
+	const auto document = QJsonDocument::fromJson(bytes, &error);
+	if (error.error != QJsonParseError::NoError) {
+		LOG(("Config Error: Failed to parse dns response JSON, error: %1"
+			).arg(error.errorString()));
+		return {};
+	} else if (!document.isObject()) {
+		LOG(("Config Error: Not an object received in dns response JSON."));
+		return {};
+	}
+	const auto response = document.object();
+	const auto answerIt = response.find("Answer");
+	if (answerIt == response.constEnd()) {
+		LOG(("Config Error: Could not find Answer in dns response JSON."));
+		return {};
+	} else if (!(*answerIt).isArray()) {
+		LOG(("Config Error: Not an array received "
+			"in Answer in dns response JSON."));
+		return {};
+	}
+
+	auto result = std::vector<DnsEntry>();
+	for (const auto elem : (*answerIt).toArray()) {
+		if (!elem.isObject()) {
+			LOG(("Config Error: Not an object found "
+				"in Answer array in dns response JSON."));
+			continue;
+		}
+		const auto object = elem.toObject();
+		if (typeRestriction) {
+			const auto typeIt = object.find("type");
+			const auto type = int(std::round((*typeIt).toDouble()));
+			if (!(*typeIt).isDouble()) {
+				LOG(("Config Error: Not a number in type field "
+					"in Answer array in dns response JSON."));
+				continue;
+			} else if (type != *typeRestriction) {
+				continue;
+			}
+		}
+		const auto dataIt = object.find("data");
+		if (dataIt == object.constEnd()) {
+			LOG(("Config Error: Could not find data "
+				"in Answer array entry in dns response JSON."));
+			continue;
+		} else if (!(*dataIt).isString()) {
+			LOG(("Config Error: Not a string data found "
+				"in Answer array entry in dns response JSON."));
+			continue;
+		}
+
+		const auto ttlIt = object.find("TTL");
+		const auto ttl = (ttlIt != object.constEnd())
+			? crl::time(std::round((*ttlIt).toDouble()))
+			: crl::time(0);
+		result.push_back({ (*dataIt).toString(), ttl });
+	}
+	return result;
+}
+
+ServiceWebRequest::ServiceWebRequest(not_null<QNetworkReply*> reply)
+: reply(reply.get()) {
+}
+
+ServiceWebRequest::ServiceWebRequest(ServiceWebRequest &&other)
+: reply(base::take(other.reply)) {
+}
+
+ServiceWebRequest &ServiceWebRequest::operator=(ServiceWebRequest &&other) {
+	if (reply != other.reply) {
+		destroy();
+		reply = base::take(other.reply);
+	}
+	return *this;
+}
+
+void ServiceWebRequest::destroy() {
+	if (const auto value = base::take(reply)) {
+		value->disconnect(
+			value,
+			&QNetworkReply::finished,
+			nullptr,
+			nullptr);
+		value->abort();
+		value->deleteLater();
+	}
+}
+
+ServiceWebRequest::~ServiceWebRequest() {
+	if (reply) {
+		reply->deleteLater();
+	}
+}
+
+DomainResolver::DomainResolver(Fn<void(
+	const QString &host,
+	const QStringList &ips,
+	crl::time expireAt)> callback)
+: _callback(std::move(callback)) {
+	_manager.setProxy(QNetworkProxy::NoProxy);
+}
+
+void DomainResolver::resolve(const QString &domain) {
+	resolve({ domain, false });
+	resolve({ domain, true });
+}
+
+void DomainResolver::resolve(const AttemptKey &key) {
+	if (_attempts.find(key) != end(_attempts)) {
+		return;
+	} else if (_requests.find(key) != end(_requests)) {
+		return;
+	}
+	const auto i = _cache.find(key);
+	_lastTimestamp = crl::now();
+	if (i != end(_cache) && i->second.expireAt > _lastTimestamp) {
+		checkExpireAndPushResult(key.domain);
+		return;
+	}
+
+	auto attempts = std::vector<Attempt>();
+	auto domains = DnsDomains();
+	std::random_device rd;
+	ranges::shuffle(domains, std::mt19937(rd()));
+	const auto takeDomain = [&] {
+		const auto result = domains.back();
+		domains.pop_back();
+		return result;
+	};
+	const auto shuffle = [&](int from, int till) {
+		Expects(till > from);
+
+		ranges::shuffle(
+			begin(attempts) + from,
+			begin(attempts) + till,
+			std::mt19937(rd()));
+	};
+
+	attempts.push_back({ Type::Google, "dns.google.com" });
+	attempts.push_back({ Type::Google, takeDomain(), "dns" });
+	attempts.push_back({ Type::Mozilla, "mozilla.cloudflare-dns.com" });
+	while (!domains.empty()) {
+		attempts.push_back({ Type::Google, takeDomain(), "dns" });
+	}
+
+	shuffle(0, 2);
+
+	ranges::reverse(attempts); // We go from last to first.
+
+	_attempts.emplace(key, Attempts{ std::move(attempts) });
+	sendNextRequest(key);
+}
+
+void DomainResolver::checkExpireAndPushResult(const QString &domain) {
+	const auto ipv4 = _cache.find({ domain, false });
+	if (ipv4 == end(_cache) || ipv4->second.expireAt <= _lastTimestamp) {
+		return;
+	}
+	auto result = ipv4->second;
+	const auto ipv6 = _cache.find({ domain, true });
+	if (ipv6 != end(_cache) && ipv6->second.expireAt > _lastTimestamp) {
+		result.ips.append(ipv6->second.ips);
+		accumulate_min(result.expireAt, ipv6->second.expireAt);
+	}
+	InvokeQueued(this, [=] {
+		_callback(domain, result.ips, result.expireAt);
+	});
+}
+
+void DomainResolver::sendNextRequest(const AttemptKey &key) {
+	auto i = _attempts.find(key);
+	if (i == end(_attempts)) {
+		return;
+	}
+	auto &attempts = i->second;
+	auto &list = attempts.list;
+	const auto attempt = list.back();
+	list.pop_back();
+
+	if (!list.empty()) {
+		base::call_delayed(kSendNextTimeout, &attempts.guard, [=] {
+			sendNextRequest(key);
+		});
+	}
+	performRequest(key, attempt);
+}
+
+void DomainResolver::performRequest(
+		const AttemptKey &key,
+		const Attempt &attempt) {
+	auto url = QUrl();
+	url.setScheme("https");
+	auto request = QNetworkRequest();
+	switch (attempt.type) {
+	case Type::Mozilla: {
+		url.setHost(attempt.data);
+		url.setPath("/dns-query");
+		url.setQuery(QStringLiteral("name=%1&type=%2&random_padding=%3"
+		).arg(key.domain
+		).arg(key.ipv6 ? 28 : 1
+		).arg(GenerateDnsRandomPadding()));
+		request.setRawHeader("accept", "application/dns-json");
+	} break;
+	case Type::Google: {
+		url.setHost(attempt.data);
+		url.setPath("/resolve");
+		url.setQuery(QStringLiteral("name=%1&type=%2&random_padding=%3"
+		).arg(key.domain
+		).arg(key.ipv6 ? 28 : 1
+		).arg(GenerateDnsRandomPadding()));
+		if (!attempt.host.isEmpty()) {
+			const auto host = attempt.host + ".google.com";
+			request.setRawHeader("Host", host.toLatin1());
+		}
+	} break;
+	default: Unexpected("Type in SpecialConfigRequest::performRequest.");
+	}
+	request.setUrl(url);
+	request.setRawHeader("User-Agent", DnsUserAgent());
+	const auto i = _requests.emplace(
+		key,
+		std::vector<ServiceWebRequest>()).first;
+	const auto reply = i->second.emplace_back(
+		_manager.get(request)
+	).reply;
+	connect(reply, &QNetworkReply::finished, this, [=] {
+		requestFinished(key, reply);
+	});
+}
+
+void DomainResolver::requestFinished(
+		const AttemptKey &key,
+		not_null<QNetworkReply*> reply) {
+	const auto result = finalizeRequest(key, reply);
+	const auto response = ParseDnsResponse(result);
+	if (response.empty()) {
+		return;
+	}
+	_requests.erase(key);
+	_attempts.erase(key);
+
+	auto entry = CacheEntry();
+	auto ttl = kMaxTimeToLive;
+	for (const auto &item : response) {
+		entry.ips.push_back(item.data);
+		ttl = std::min(
+			ttl,
+			std::max(item.TTL * crl::time(1000), kMinTimeToLive));
+	}
+	_lastTimestamp = crl::now();
+	entry.expireAt = _lastTimestamp + ttl;
+	_cache[key] = std::move(entry);
+
+	checkExpireAndPushResult(key.domain);
+}
+
+QByteArray DomainResolver::finalizeRequest(
+		const AttemptKey &key,
+		not_null<QNetworkReply*> reply) {
+	if (reply->error() != QNetworkReply::NoError) {
+		LOG(("Resolve Error: Failed to get response, error: %2 (%3)"
+			).arg(reply->errorString()
+			).arg(reply->error()));
+	}
+	const auto result = reply->readAll();
+	const auto i = _requests.find(key);
+	if (i != end(_requests)) {
+		auto &requests = i->second;
+		const auto from = ranges::remove(
+			requests,
+			reply,
+			[](const ServiceWebRequest &request) { return request.reply; });
+		requests.erase(from, end(requests));
+		if (requests.empty()) {
+			_requests.erase(i);
+		}
+	}
+	return result;
+}
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.h b/Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.h
new file mode 100644
index 000000000..cb1979bbb
--- /dev/null
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_domain_resolver.h
@@ -0,0 +1,106 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "base/weak_ptr.h"
+
+#include <QtCore/QPointer>
+#include <QtNetwork/QNetworkReply>
+#include <optional>
+
+namespace MTP::details {
+
+[[nodiscard]] const std::vector<QString> &DnsDomains();
+[[nodiscard]] QString GenerateDnsRandomPadding();
+[[nodiscard]] QByteArray DnsUserAgent();
+
+struct DnsEntry {
+	QString data;
+	crl::time TTL = 0;
+};
+
+[[nodiscard]] std::vector<DnsEntry> ParseDnsResponse(
+	const QByteArray &bytes,
+	std::optional<int> typeRestriction = std::nullopt);
+
+struct ServiceWebRequest {
+	ServiceWebRequest(not_null<QNetworkReply*> reply);
+	ServiceWebRequest(ServiceWebRequest &&other);
+	ServiceWebRequest &operator=(ServiceWebRequest &&other);
+	~ServiceWebRequest();
+
+	void destroy();
+
+	QPointer<QNetworkReply> reply;
+};
+
+class DomainResolver : public QObject {
+public:
+	DomainResolver(Fn<void(
+		const QString &domain,
+		const QStringList &ips,
+		crl::time expireAt)> callback);
+
+	void resolve(const QString &domain);
+
+private:
+	enum class Type {
+		Mozilla,
+		Google,
+	};
+	struct Attempt {
+		Type type;
+		QString data;
+		QString host;
+	};
+	struct AttemptKey {
+		QString domain;
+		bool ipv6 = false;
+
+		inline bool operator<(const AttemptKey &other) const {
+			return (domain < other.domain)
+				|| (domain == other.domain && !ipv6 && other.ipv6);
+		}
+		inline bool operator==(const AttemptKey &other) const {
+			return (domain == other.domain) && (ipv6 == other.ipv6);
+		}
+	};
+	struct CacheEntry {
+		QStringList ips;
+		crl::time expireAt = 0;
+	};
+	struct Attempts {
+		std::vector<Attempt> list;
+		base::has_weak_ptr guard;
+	};
+
+	void resolve(const AttemptKey &key);
+	void sendNextRequest(const AttemptKey &key);
+	void performRequest(const AttemptKey &key, const Attempt &attempt);
+	void checkExpireAndPushResult(const QString &domain);
+	void requestFinished(
+		const AttemptKey &key,
+		not_null<QNetworkReply*> reply);
+	QByteArray finalizeRequest(
+		const AttemptKey &key,
+		not_null<QNetworkReply*> reply);
+
+	Fn<void(
+		const QString &domain,
+		const QStringList &ips,
+		crl::time expireAt)> _callback;
+
+	QNetworkAccessManager _manager;
+	std::map<AttemptKey, Attempts> _attempts;
+	std::map<AttemptKey, std::vector<ServiceWebRequest>> _requests;
+	std::map<AttemptKey, CacheEntry> _cache;
+	crl::time _lastTimestamp = 0;
+
+};
+
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_rsa_public_key.cpp
similarity index 98%
rename from Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_rsa_public_key.cpp
index ca10f0a29..8d47ed822 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_rsa_public_key.cpp
@@ -5,12 +5,11 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtproto_rsa_public_key.h"
+#include "mtproto/details/mtproto_rsa_public_key.h"
 
 #include "base/openssl_help.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 namespace {
 #if OPENSSL_VERSION_NUMBER < 0x10100000L || (defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x2070000fL)
 
@@ -292,5 +291,4 @@ bytes::vector RSAPublicKey::encryptOAEPpadding(
 	return _private->encryptOAEPpadding(data);
 }
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.h b/Telegram/SourceFiles/mtproto/details/mtproto_rsa_public_key.h
similarity index 94%
rename from Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.h
rename to Telegram/SourceFiles/mtproto/details/mtproto_rsa_public_key.h
index 402b17426..86978061d 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_rsa_public_key.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_rsa_public_key.h
@@ -9,8 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "base/bytes.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 
 // this class holds an RSA public key and can encrypt fixed-size messages with it
 class RSAPublicKey final {
@@ -47,5 +46,4 @@ private:
 
 };
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
index 61dd8e6c7..ad9901b2b 100644
--- a/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_serialized_request.h
@@ -11,7 +11,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include <crl/crl_time.h>
 
-namespace MTP::details {
+namespace MTP {
+namespace details {
 
 class RequestData;
 class SerializedRequest;
@@ -44,7 +45,7 @@ public:
 	template <
 		typename Request,
 		typename = std::enable_if_t<tl::is_boxed_v<Request>>>
-	static SerializedRequest Serialize(const Request &request);
+		static SerializedRequest Serialize(const Request &request);
 
 	// For template MTP requests and MTPBoxed instantiation.
 	template <typename Accumulator>
@@ -102,4 +103,5 @@ SerializedRequest SerializedRequest::Serialize(const Request &request) {
 	return serialized;
 }
 
-} // namespace MTP::details
+} // namespace details
+} // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_tcp_socket.cpp
similarity index 97%
rename from Telegram/SourceFiles/mtproto/mtproto_tcp_socket.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_tcp_socket.cpp
index d2fbd6ad9..53680461a 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_tcp_socket.cpp
@@ -5,12 +5,11 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtproto_tcp_socket.h"
+#include "mtproto/details/mtproto_tcp_socket.h"
 
 #include "base/invoke_queued.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 
 TcpSocket::TcpSocket(not_null<QThread*> thread, const QNetworkProxy &proxy)
 : AbstractSocket(thread) {
@@ -153,5 +152,4 @@ void TcpSocket::handleError(int errorCode) {
 	_error.fire({});
 }
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.h b/Telegram/SourceFiles/mtproto/details/mtproto_tcp_socket.h
similarity index 87%
rename from Telegram/SourceFiles/mtproto/mtproto_tcp_socket.h
rename to Telegram/SourceFiles/mtproto/details/mtproto_tcp_socket.h
index c8919fce2..6c8bac882 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_tcp_socket.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_tcp_socket.h
@@ -7,10 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/mtproto_abstract_socket.h"
+#include "mtproto/details/mtproto_abstract_socket.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 
 class TcpSocket final : public AbstractSocket {
 public:
@@ -35,5 +34,4 @@ private:
 
 };
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtproto_tls_socket.cpp b/Telegram/SourceFiles/mtproto/details/mtproto_tls_socket.cpp
similarity index 99%
rename from Telegram/SourceFiles/mtproto/mtproto_tls_socket.cpp
rename to Telegram/SourceFiles/mtproto/details/mtproto_tls_socket.cpp
index 8aa38f523..385dff13a 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_tls_socket.cpp
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_tls_socket.cpp
@@ -5,9 +5,9 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/mtproto_tls_socket.h"
+#include "mtproto/details/mtproto_tls_socket.h"
 
-#include "mtproto/mtproto_tcp_socket.h"
+#include "mtproto/details/mtproto_tcp_socket.h"
 #include "base/openssl_help.h"
 #include "base/bytes.h"
 #include "base/invoke_queued.h"
@@ -16,8 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtCore/QtEndian>
 #include <range/v3/algorithm/reverse.hpp>
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 namespace {
 
 constexpr auto kMaxGrease = 8;
@@ -778,5 +777,4 @@ void TlsSocket::handleError(int errorCode) {
 	_error.fire({});
 }
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/mtproto_tls_socket.h b/Telegram/SourceFiles/mtproto/details/mtproto_tls_socket.h
similarity index 92%
rename from Telegram/SourceFiles/mtproto/mtproto_tls_socket.h
rename to Telegram/SourceFiles/mtproto/details/mtproto_tls_socket.h
index a93ef4014..01848230a 100644
--- a/Telegram/SourceFiles/mtproto/mtproto_tls_socket.h
+++ b/Telegram/SourceFiles/mtproto/details/mtproto_tls_socket.h
@@ -7,10 +7,9 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include "mtproto/mtproto_abstract_socket.h"
+#include "mtproto/details/mtproto_abstract_socket.h"
 
-namespace MTP {
-namespace internal {
+namespace MTP::details {
 
 class TlsSocket final : public AbstractSocket {
 public:
@@ -64,5 +63,4 @@ private:
 
 };
 
-} // namespace internal
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/facade.cpp b/Telegram/SourceFiles/mtproto/facade.cpp
index 920a2c723..a776a958e 100644
--- a/Telegram/SourceFiles/mtproto/facade.cpp
+++ b/Telegram/SourceFiles/mtproto/facade.cpp
@@ -12,7 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_account.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 int PauseLevel = 0;
@@ -36,7 +36,7 @@ void unpause() {
 	}
 }
 
-} // namespace internal
+} // namespace details
 
 Instance *MainInstance() {
 	return Core::IsAppLaunched()
diff --git a/Telegram/SourceFiles/mtproto/facade.h b/Telegram/SourceFiles/mtproto/facade.h
index cffb33584..75868ce83 100644
--- a/Telegram/SourceFiles/mtproto/facade.h
+++ b/Telegram/SourceFiles/mtproto/facade.h
@@ -11,13 +11,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/mtp_instance.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 
 [[nodiscard]] bool paused();
 void pause();
 void unpause();
 
-} // namespace internal
+} // namespace details
 
 // send(MTPhelp_GetConfig(), MTP::configDcId(dc)) - for dc enumeration
 constexpr ShiftedDcId configDcId(DcId dcId) {
@@ -37,23 +37,24 @@ constexpr ShiftedDcId updaterDcId(DcId dcId) {
 constexpr auto kDownloadSessionsCount = 2;
 constexpr auto kUploadSessionsCount = 2;
 
-namespace internal {
+namespace details {
 
 constexpr ShiftedDcId downloadDcId(DcId dcId, int index) {
 	static_assert(kDownloadSessionsCount < kMaxMediaDcCount, "Too large MTPDownloadSessionsCount!");
 	return ShiftDcId(dcId, kBaseDownloadDcShift + index);
 };
 
-} // namespace internal
+} // namespace details
 
 // send(req, callbacks, MTP::downloadDcId(dc, index)) - for download shifted dc id
 inline ShiftedDcId downloadDcId(DcId dcId, int index) {
 	Expects(index >= 0 && index < kDownloadSessionsCount);
-	return internal::downloadDcId(dcId, index);
+	return details::downloadDcId(dcId, index);
 }
 
 inline constexpr bool isDownloadDcId(ShiftedDcId shiftedDcId) {
-	return (shiftedDcId >= internal::downloadDcId(0, 0)) && (shiftedDcId < internal::downloadDcId(0, kDownloadSessionsCount - 1) + kDcShift);
+	return (shiftedDcId >= details::downloadDcId(0, 0))
+		&& (shiftedDcId < details::downloadDcId(0, kDownloadSessionsCount - 1) + kDcShift);
 }
 
 inline bool isCdnDc(MTPDdcOption::Flags flags) {
@@ -75,25 +76,26 @@ inline DcId getTemporaryIdFromRealDcId(ShiftedDcId shiftedDcId) {
 	return (dcId < Instance::Config::kTemporaryMainDc) ? (dcId + Instance::Config::kTemporaryMainDc) : 0;
 }
 
-namespace internal {
+namespace details {
 
 constexpr ShiftedDcId uploadDcId(DcId dcId, int index) {
 	static_assert(kUploadSessionsCount < kMaxMediaDcCount, "Too large MTPUploadSessionsCount!");
 	return ShiftDcId(dcId, kBaseUploadDcShift + index);
 };
 
-} // namespace internal
+} // namespace details
 
 // send(req, callbacks, MTP::uploadDcId(index)) - for upload shifted dc id
 // uploading always to the main dc so BareDcId(result) == 0
 inline ShiftedDcId uploadDcId(int index) {
 	Expects(index >= 0 && index < kUploadSessionsCount);
 
-	return internal::uploadDcId(0, index);
+	return details::uploadDcId(0, index);
 };
 
 constexpr bool isUploadDcId(ShiftedDcId shiftedDcId) {
-	return (shiftedDcId >= internal::uploadDcId(0, 0)) && (shiftedDcId < internal::uploadDcId(0, kUploadSessionsCount - 1) + kDcShift);
+	return (shiftedDcId >= details::uploadDcId(0, 0))
+		&& (shiftedDcId < details::uploadDcId(0, kUploadSessionsCount - 1) + kDcShift);
 }
 
 inline ShiftedDcId destroyKeyNextDcId(ShiftedDcId shiftedDcId) {
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index 2af0788f0..b48ddf734 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -7,14 +7,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/mtp_instance.h"
 
+#include "mtproto/details/mtproto_dcenter.h"
+#include "mtproto/details/mtproto_rsa_public_key.h"
+#include "mtproto/special_config_request.h"
 #include "mtproto/session.h"
 #include "mtproto/dc_options.h"
-#include "mtproto/dcenter.h"
 #include "mtproto/config_loader.h"
-#include "mtproto/special_config_request.h"
-#include "mtproto/connection.h"
 #include "mtproto/sender.h"
-#include "mtproto/mtproto_rsa_public_key.h"
 #include "storage/localstorage.h"
 #include "calls/calls_instance.h"
 #include "main/main_session.h" // Session::Exists.
@@ -35,14 +34,13 @@ constexpr auto kConfigBecomesOldIn = 2 * 60 * crl::time(1000);
 constexpr auto kConfigBecomesOldForBlockedIn = 8 * crl::time(1000);
 constexpr auto kCheckKeyEach = 60 * crl::time(1000);
 
-using namespace internal;
 using namespace details;
 
 std::atomic<int> GlobalAtomicRequestId = 0;
 
 } // namespace
 
-namespace internal {
+namespace details {
 
 int GetNextRequestId() {
 	const auto result = ++GlobalAtomicRequestId;
@@ -52,7 +50,7 @@ int GetNextRequestId() {
 	return result;
 }
 
-} // namespace internal
+} // namespace details
 
 class Instance::Private : private Sender {
 public:
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 7f6d7f463..834ef947d 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -11,14 +11,14 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "mtproto/details/mtproto_serialized_request.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 
 class Dcenter;
 class Session;
 
 [[nodiscard]] int GetNextRequestId();
 
-} // namespace internal
+} // namespace details
 
 class DcOptions;
 class AuthKey;
@@ -131,7 +131,7 @@ public:
 			ShiftedDcId shiftedDcId = 0,
 			crl::time msCanWait = 0,
 			mtpRequestId afterRequestId = 0) {
-		const auto requestId = internal::GetNextRequestId();
+		const auto requestId = details::GetNextRequestId();
 		sendSerialized(
 			requestId,
 			details::SerializedRequest::Serialize(request),
@@ -162,7 +162,7 @@ public:
 	mtpRequestId sendProtocolMessage(
 			ShiftedDcId shiftedDcId,
 			const Request &request) {
-		const auto requestId = internal::GetNextRequestId();
+		const auto requestId = details::GetNextRequestId();
 		sendRequest(
 			requestId,
 			details::SerializedRequest::Serialize(request),
diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp b/Telegram/SourceFiles/mtproto/mtproto_concurrent_sender.cpp
similarity index 98%
rename from Telegram/SourceFiles/mtproto/concurrent_sender.cpp
rename to Telegram/SourceFiles/mtproto/mtproto_concurrent_sender.cpp
index 3d484296a..b211cda30 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.cpp
+++ b/Telegram/SourceFiles/mtproto/mtproto_concurrent_sender.cpp
@@ -5,7 +5,7 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/concurrent_sender.h"
+#include "mtproto/mtproto_concurrent_sender.h"
 
 #include "mtproto/mtp_instance.h"
 #include "mtproto/mtproto_rpc_sender.h"
@@ -135,7 +135,7 @@ void ConcurrentSender::RequestBuilder::setAfter(
 }
 
 mtpRequestId ConcurrentSender::RequestBuilder::send() {
-	const auto requestId = internal::GetNextRequestId();
+	const auto requestId = details::GetNextRequestId();
 	const auto dcId = _dcId;
 	const auto msCanWait = _canWait;
 	const auto afterRequestId = _afterRequestId;
diff --git a/Telegram/SourceFiles/mtproto/concurrent_sender.h b/Telegram/SourceFiles/mtproto/mtproto_concurrent_sender.h
similarity index 99%
rename from Telegram/SourceFiles/mtproto/concurrent_sender.h
rename to Telegram/SourceFiles/mtproto/mtproto_concurrent_sender.h
index 68fb22781..74c1c4482 100644
--- a/Telegram/SourceFiles/mtproto/concurrent_sender.h
+++ b/Telegram/SourceFiles/mtproto/mtproto_concurrent_sender.h
@@ -7,13 +7,14 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#include <rpl/details/callable.h>
 #include "base/bytes.h"
 #include "base/weak_ptr.h"
 #include "base/flat_map.h"
 #include "mtproto/core_types.h"
 #include "mtproto/details/mtproto_serialized_request.h"
 
+#include <rpl/details/callable.h>
+
 #ifndef _DEBUG
 #define MTP_SENDER_USE_GENERIC_HANDLERS
 #endif // !_DEBUG
diff --git a/Telegram/SourceFiles/mtproto/session.cpp b/Telegram/SourceFiles/mtproto/session.cpp
index b81859c27..563f8de2f 100644
--- a/Telegram/SourceFiles/mtproto/session.cpp
+++ b/Telegram/SourceFiles/mtproto/session.cpp
@@ -7,18 +7,17 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/session.h"
 
-#include "mtproto/connection.h"
-#include "mtproto/dcenter.h"
+#include "mtproto/details/mtproto_dcenter.h"
+#include "mtproto/session_private.h"
 #include "mtproto/mtproto_auth_key.h"
 #include "base/unixtime.h"
 #include "base/openssl_help.h"
-#include "core/crash_reports.h"
 #include "facades.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 
-ConnectionOptions::ConnectionOptions(
+SessionOptions::SessionOptions(
 	const QString &systemLangCode,
 	const QString &cloudLangCode,
 	const QString &langPackName,
@@ -50,9 +49,9 @@ void SessionData::withSession(Callback &&callback) {
 	}
 }
 
-void SessionData::notifyConnectionInited(const ConnectionOptions &options) {
+void SessionData::notifyConnectionInited(const SessionOptions &options) {
 	// #TODO race
-	const auto current = connectionOptions();
+	const auto current = this->options();
 	if (current.cloudLangCode == _options.cloudLangCode
 		&& current.systemLangCode == _options.systemLangCode
 		&& current.langPackName == _options.langPackName
@@ -163,7 +162,7 @@ Session::Session(
 }
 
 Session::~Session() {
-	Expects(!_connection);
+	Expects(!_private);
 
 	if (_myKeyCreation != CreatingKeyType::None) {
 		releaseKeyCreationOnFail();
@@ -177,11 +176,11 @@ void Session::watchDcKeyChanges() {
 	}) | rpl::start_with_next([=] {
 		DEBUG_LOG(("AuthKey Info: dcTemporaryKeyChanged in Session %1"
 			).arg(_shiftedDcId));
-		if (const auto connection = _connection) {
-			InvokeQueued(connection, [=] {
+		if (const auto captured = _private) {
+			InvokeQueued(captured, [=] {
 				DEBUG_LOG(("AuthKey Info: calling Connection::updateAuthKey in Session %1"
 					).arg(_shiftedDcId));
-				connection->updateAuthKey();
+				captured->updateAuthKey();
 			});
 		}
 	}, _lifetime);
@@ -190,20 +189,20 @@ void Session::watchDcKeyChanges() {
 void Session::watchDcOptionsChanges() {
 	_instance->dcOptions()->changed(
 	) | rpl::filter([=](DcId dcId) {
-		return (BareDcId(_shiftedDcId) == dcId) && (_connection != nullptr);
+		return (BareDcId(_shiftedDcId) == dcId) && (_private != nullptr);
 	}) | rpl::start_with_next([=] {
-		InvokeQueued(_connection, [connection = _connection] {
-			connection->dcOptionsChanged();
+		InvokeQueued(_private, [captured = _private] {
+			captured->dcOptionsChanged();
 		});
 	}, _lifetime);
 
 	if (_instance->dcOptions()->dcType(_shiftedDcId) == DcType::Cdn) {
 		_instance->dcOptions()->cdnConfigChanged(
 		) | rpl::filter([=] {
-			return (_connection != nullptr);
+			return (_private != nullptr);
 		}) | rpl::start_with_next([=] {
-			InvokeQueued(_connection, [connection = _connection] {
-				connection->cdnConfigChanged();
+			InvokeQueued(_private, [captured = _private] {
+				captured->cdnConfigChanged();
 			});
 		}, _lifetime);
 	}
@@ -211,7 +210,7 @@ void Session::watchDcOptionsChanges() {
 
 void Session::start() {
 	killConnection();
-	_connection = new Connection(
+	_private = new SessionPrivate(
 		_instance,
 		_thread.get(),
 		_data,
@@ -231,9 +230,9 @@ void Session::restart() {
 		return;
 	}
 	refreshOptions();
-	if (const auto connection = _connection) {
-		InvokeQueued(connection, [=] {
-			connection->restartNow();
+	if (const auto captured = _private) {
+		InvokeQueued(captured, [=] {
+			captured->restartNow();
 		});
 	}
 }
@@ -248,7 +247,7 @@ void Session::refreshOptions() {
 	const auto useHttp = (proxyType != ProxyData::Type::Mtproto);
 	const auto useIPv4 = true;
 	const auto useIPv6 = Global::TryIPv6();
-	_data->setConnectionOptions(ConnectionOptions(
+	_data->setOptions(SessionOptions(
 		_instance->systemLangCode(),
 		_instance->cloudLangCode(),
 		_instance->langPackName(),
@@ -326,17 +325,17 @@ void Session::needToResumeAndSend() {
 		DEBUG_LOG(("Session Info: can't resume a killed session"));
 		return;
 	}
-	if (!_connection) {
+	if (!_private) {
 		DEBUG_LOG(("Session Info: resuming session dcWithShift %1").arg(_shiftedDcId));
 		start();
 	}
-	const auto connection = _connection;
+	const auto captured = _private;
 	const auto ping = base::take(_ping);
-	InvokeQueued(connection, [=] {
+	InvokeQueued(captured, [=] {
 		if (ping) {
-			connection->sendPingForce();
+			captured->sendPingForce();
 		} else {
-			connection->tryToSend();
+			captured->tryToSend();
 		}
 	});
 }
@@ -369,8 +368,8 @@ int32 Session::requestState(mtpRequestId requestId) const {
 	int32 result = MTP::RequestSent;
 
 	bool connected = false;
-	if (_connection) {
-		const auto s = _connection->getState();
+	if (_private) {
+		const auto s = _private->getState();
 		if (s == ConnectedState) {
 			connected = true;
 		} else if (s == ConnectingState || s == DisconnectedState) {
@@ -398,8 +397,8 @@ int32 Session::requestState(mtpRequestId requestId) const {
 int32 Session::getState() const {
 	int32 result = -86400000;
 
-	if (_connection) {
-		const auto s = _connection->getState();
+	if (_private) {
+		const auto s = _private->getState();
 		if (s == ConnectedState) {
 			return s;
 		} else if (s == ConnectingState || s == DisconnectedState) {
@@ -419,11 +418,11 @@ int32 Session::getState() const {
 }
 
 QString Session::transport() const {
-	return _connection ? _connection->transport() : QString();
+	return _private ? _private->transport() : QString();
 }
 
 void Session::sendPrepared(
-		const details::SerializedRequest &request,
+		const SerializedRequest &request,
 		crl::time msCanWait) {
 	DEBUG_LOG(("MTP Info: adding request to toSendMap, msCanWait %1"
 		).arg(msCanWait));
@@ -563,14 +562,14 @@ void Session::tryToReceive() {
 }
 
 void Session::killConnection() {
-	if (!_connection) {
+	if (!_private) {
 		return;
 	}
 
-	base::take(_connection)->deleteLater();
+	base::take(_private)->deleteLater();
 
-	Ensures(_connection == nullptr);
+	Ensures(_private == nullptr);
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/session.h b/Telegram/SourceFiles/mtproto/session.h
index 81b484afe..0e9169834 100644
--- a/Telegram/SourceFiles/mtproto/session.h
+++ b/Telegram/SourceFiles/mtproto/session.h
@@ -20,17 +20,17 @@ class Instance;
 class AuthKey;
 using AuthKeyPtr = std::shared_ptr<AuthKey>;
 
-namespace internal {
+namespace details {
 
 class Dcenter;
-class Connection;
+class SessionPrivate;
 
 enum class TemporaryKeyType;
 enum class CreatingKeyType;
 
-struct ConnectionOptions {
-	ConnectionOptions() = default;
-	ConnectionOptions(
+struct SessionOptions {
+	SessionOptions() = default;
+	SessionOptions(
 		const QString &systemLangCode,
 		const QString &cloudLangCode,
 		const QString &langPackName,
@@ -39,8 +39,6 @@ struct ConnectionOptions {
 		bool useIPv6,
 		bool useHttp,
 		bool useTcp);
-	ConnectionOptions(const ConnectionOptions &other) = default;
-	ConnectionOptions &operator=(const ConnectionOptions &other) = default;
 
 	QString systemLangCode;
 	QString cloudLangCode;
@@ -54,17 +52,17 @@ struct ConnectionOptions {
 };
 
 class Session;
-class SessionData {
+class SessionData final {
 public:
 	explicit SessionData(not_null<Session*> creator) : _owner(creator) {
 	}
 
-	void notifyConnectionInited(const ConnectionOptions &options);
-	void setConnectionOptions(ConnectionOptions options) {
+	void notifyConnectionInited(const SessionOptions &options);
+	void setOptions(SessionOptions options) {
 		QWriteLocker locker(&_optionsLock);
 		_options = options;
 	}
-	[[nodiscard]] ConnectionOptions connectionOptions() const {
+	[[nodiscard]] SessionOptions options() const {
 		QReadLocker locker(&_optionsLock);
 		return _options;
 	}
@@ -79,10 +77,10 @@ public:
 		return &_haveReceivedLock;
 	}
 
-	base::flat_map<mtpRequestId, details::SerializedRequest> &toSendMap() {
+	base::flat_map<mtpRequestId, SerializedRequest> &toSendMap() {
 		return _toSend;
 	}
-	base::flat_map<mtpMsgId, details::SerializedRequest> &haveSentMap() {
+	base::flat_map<mtpMsgId, SerializedRequest> &haveSentMap() {
 		return _haveSent;
 	}
 	base::flat_map<mtpRequestId, mtpBuffer> &haveReceivedResponses() {
@@ -92,7 +90,7 @@ public:
 		return _receivedUpdates;
 	}
 
-	// Connection -> Session interface.
+	// SessionPrivate -> Session interface.
 	void queueTryToReceive();
 	void queueNeedToResumeAndSend();
 	void queueConnectionStateChange(int newState);
@@ -118,13 +116,13 @@ private:
 	Session *_owner = nullptr;
 	mutable QMutex _ownerMutex;
 
-	ConnectionOptions _options;
+	SessionOptions _options;
 	mutable QReadWriteLock _optionsLock;
 
-	base::flat_map<mtpRequestId, details::SerializedRequest> _toSend; // map of request_id -> request, that is waiting to be sent
+	base::flat_map<mtpRequestId, SerializedRequest> _toSend; // map of request_id -> request, that is waiting to be sent
 	QReadWriteLock _toSendLock;
 
-	base::flat_map<mtpMsgId, details::SerializedRequest> _haveSent; // map of msg_id -> request, that was sent
+	base::flat_map<mtpMsgId, SerializedRequest> _haveSent; // map of msg_id -> request, that was sent
 	QReadWriteLock _haveSentLock;
 
 	base::flat_map<mtpRequestId, mtpBuffer> _receivedResponses; // map of request_id -> response that should be processed in the main thread
@@ -133,7 +131,7 @@ private:
 
 };
 
-class Session : public QObject {
+class Session final : public QObject {
 public:
 	// Main thread.
 	Session(
@@ -159,10 +157,10 @@ public:
 	[[nodiscard]] AuthKeyPtr getTemporaryKey(TemporaryKeyType type) const;
 	[[nodiscard]] bool connectionInited() const;
 	void sendPrepared(
-		const details::SerializedRequest &request,
+		const SerializedRequest &request,
 		crl::time msCanWait = 0);
 
-	// Connection thread.
+	// SessionPrivate thread.
 	[[nodiscard]] CreatingKeyType acquireKeyCreation(TemporaryKeyType type);
 	[[nodiscard]] bool releaseKeyCreationOnDone(
 		const AuthKeyPtr &temporaryKey,
@@ -201,7 +199,7 @@ private:
 	const std::shared_ptr<SessionData> _data;
 	const not_null<QThread*> _thread;
 
-	Connection *_connection = nullptr;
+	SessionPrivate *_private = nullptr;
 
 	bool _killed = false;
 	bool _needToReceive = false;
@@ -221,5 +219,5 @@ private:
 
 };
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection.cpp b/Telegram/SourceFiles/mtproto/session_private.cpp
similarity index 94%
rename from Telegram/SourceFiles/mtproto/connection.cpp
rename to Telegram/SourceFiles/mtproto/session_private.cpp
index f8b4a9bb5..ba718f8c2 100644
--- a/Telegram/SourceFiles/mtproto/connection.cpp
+++ b/Telegram/SourceFiles/mtproto/session_private.cpp
@@ -5,26 +5,23 @@ the official desktop application for the Telegram messaging service.
 For license and copyright information please follow this link:
 https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
-#include "mtproto/connection.h"
+#include "mtproto/session_private.h"
 
 #include "mtproto/details/mtproto_bound_key_creator.h"
+#include "mtproto/details/mtproto_dcenter.h"
 #include "mtproto/details/mtproto_dump_to_text.h"
+#include "mtproto/details/mtproto_rsa_public_key.h"
 #include "mtproto/session.h"
-#include "mtproto/mtproto_rsa_public_key.h"
 #include "mtproto/mtproto_rpc_sender.h"
 #include "mtproto/dc_options.h"
-#include "mtproto/dcenter.h"
 #include "mtproto/connection_abstract.h"
-#include "zlib.h"
-#include "core/application.h"
-#include "core/launcher.h"
-#include "lang/lang_keys.h"
 #include "base/openssl_help.h"
 #include "base/qthelp_url.h"
 #include "base/unixtime.h"
+#include "zlib.h"
 
 namespace MTP {
-namespace internal {
+namespace details {
 namespace {
 
 constexpr auto kIntSize = static_cast<int>(sizeof(mtpPrime));
@@ -42,6 +39,7 @@ constexpr auto kBindKeyAdditionalExpiresTimeout = TimeId(30);
 constexpr auto kTestModeDcIdShift = 10000;
 constexpr auto kCheckSentRequestsEach = 1 * crl::time(1000);
 constexpr auto kKeyOldEnoughForDestroy = 60 * crl::time(1000);
+constexpr auto kSentContainerLives = 600 * crl::time(1000);
 
 // If we can't connect for this time we will ask _instance to update config.
 constexpr auto kRequestConfigTimeout = 8 * crl::time(1000);
@@ -56,7 +54,8 @@ constexpr auto kCheckSentRequestTimeout = 10 * crl::time(1000);
 // when resending request or checking its state.
 constexpr auto kSendStateRequestWaiting = crl::time(1000);
 
-constexpr auto kSentContainerLives = 600 * crl::time(1000);
+// How much time to wait for some more requests, when sending msg acks.
+constexpr auto kAckSendWaiting = 10 * crl::time(1000);
 
 using namespace details;
 
@@ -113,7 +112,7 @@ void WrapInvokeAfter(
 
 } // namespace
 
-Connection::Connection(
+SessionPrivate::SessionPrivate(
 	not_null<Instance*> instance,
 	not_null<QThread*> thread,
 	std::shared_ptr<SessionData> data,
@@ -144,7 +143,7 @@ Connection::Connection(
 	});
 }
 
-Connection::~Connection() {
+SessionPrivate::~SessionPrivate() {
 	releaseKeyCreationOnFail();
 	doDisconnect();
 
@@ -152,7 +151,7 @@ Connection::~Connection() {
 	Expects(_testConnections.empty());
 }
 
-void Connection::appendTestConnection(
+void SessionPrivate::appendTestConnection(
 		DcOptions::Variants::Protocol protocol,
 		const QString &ip,
 		int port,
@@ -168,7 +167,7 @@ void Connection::appendTestConnection(
 			protocol,
 			thread(),
 			protocolSecret,
-			_connectionOptions->proxy),
+			_options->proxy),
 		priority
 	});
 	const auto weak = _testConnections.back().data.get();
@@ -201,7 +200,7 @@ void Connection::appendTestConnection(
 	});
 }
 
-int16 Connection::getProtocolDcId() const {
+int16 SessionPrivate::getProtocolDcId() const {
 	const auto dcId = BareDcId(_shiftedDcId);
 	const auto simpleDcId = isTemporaryDcId(dcId)
 		? getRealIdFromTemporaryDcId(dcId)
@@ -214,7 +213,7 @@ int16 Connection::getProtocolDcId() const {
 		: testedDcId;
 }
 
-void Connection::checkSentRequests() {
+void SessionPrivate::checkSentRequests() {
 	clearOldContainers();
 
 	auto restarting = false;
@@ -246,7 +245,7 @@ void Connection::checkSentRequests() {
 	}
 }
 
-void Connection::clearOldContainers() {
+void SessionPrivate::clearOldContainers() {
 	auto resent = false;
 	const auto now = crl::now();
 	for (auto i = _sentContainers.begin(); i != _sentContainers.end();) {
@@ -274,7 +273,7 @@ void Connection::clearOldContainers() {
 	}
 }
 
-void Connection::destroyAllConnections() {
+void SessionPrivate::destroyAllConnections() {
 	clearUnboundKeyCreator();
 	_waitForBetterTimer.cancel();
 	_waitForReceivedTimer.cancel();
@@ -283,20 +282,20 @@ void Connection::destroyAllConnections() {
 	_connection = nullptr;
 }
 
-void Connection::cdnConfigChanged() {
+void SessionPrivate::cdnConfigChanged() {
 	connectToServer(true);
 }
 
-int32 Connection::getShiftedDcId() const {
+int32 SessionPrivate::getShiftedDcId() const {
 	return _shiftedDcId;
 }
 
-void Connection::dcOptionsChanged() {
+void SessionPrivate::dcOptionsChanged() {
 	_retryTimeout = 1;
 	connectToServer(true);
 }
 
-int32 Connection::getState() const {
+int32 SessionPrivate::getState() const {
 	QReadLocker lock(&_stateMutex);
 	int32 result = _state;
 	if (_state < 0) {
@@ -310,17 +309,17 @@ int32 Connection::getState() const {
 	return result;
 }
 
-QString Connection::transport() const {
+QString SessionPrivate::transport() const {
 	QReadLocker lock(&_stateMutex);
 	if (!_connection || (_state < 0)) {
 		return QString();
 	}
 
-	Assert(_connectionOptions != nullptr);
+	Assert(_options != nullptr);
 	return _connection->transport();
 }
 
-bool Connection::setState(int state, int ifState) {
+bool SessionPrivate::setState(int state, int ifState) {
 	if (ifState != kUpdateStateAlways) {
 		QReadLocker lock(&_stateMutex);
 		if (_state != ifState) {
@@ -344,7 +343,7 @@ bool Connection::setState(int state, int ifState) {
 	return true;
 }
 
-void Connection::resetSession() {
+void SessionPrivate::resetSession() {
 	MTP_LOG(_shiftedDcId, ("Resetting session!"));
 	_needSessionReset = false;
 
@@ -354,7 +353,7 @@ void Connection::resetSession() {
 	_sessionData->queueResetDone();
 }
 
-void Connection::changeSessionId() {
+void SessionPrivate::changeSessionId() {
 	auto sessionId = _sessionId;
 	do {
 		sessionId = openssl::RandomValue<uint64>();
@@ -371,13 +370,13 @@ void Connection::changeSessionId() {
 	_receivedMessageIds.clear();
 }
 
-uint32 Connection::nextRequestSeqNumber(bool needAck) {
+uint32 SessionPrivate::nextRequestSeqNumber(bool needAck) {
 	const auto result = _messagesCounter;
 	_messagesCounter += (needAck ? 1 : 0);
 	return result * 2 + (needAck ? 1 : 0);
 }
 
-bool Connection::realDcTypeChanged() {
+bool SessionPrivate::realDcTypeChanged() {
 	const auto now = _instance->dcOptions()->dcType(_shiftedDcId);
 	if (_realDcType == now) {
 		return false;
@@ -386,7 +385,7 @@ bool Connection::realDcTypeChanged() {
 	return true;
 }
 
-bool Connection::markSessionAsStarted() {
+bool SessionPrivate::markSessionAsStarted() {
 	if (_sessionMarkedAsStarted) {
 		return false;
 	}
@@ -394,7 +393,7 @@ bool Connection::markSessionAsStarted() {
 	return true;
 }
 
-mtpMsgId Connection::prepareToSend(
+mtpMsgId SessionPrivate::prepareToSend(
 		SerializedRequest &request,
 		mtpMsgId currentLastId,
 		bool forceNewMsgId) {
@@ -419,7 +418,7 @@ mtpMsgId Connection::prepareToSend(
 	return currentLastId;
 }
 
-mtpMsgId Connection::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
+mtpMsgId SessionPrivate::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
 	Expects(request->size() > 8);
 
 	const auto oldMsgId = request.getMsgId();
@@ -472,7 +471,7 @@ mtpMsgId Connection::replaceMsgId(SerializedRequest &request, mtpMsgId newId) {
 	return newId;
 }
 
-mtpMsgId Connection::placeToContainer(
+mtpMsgId SessionPrivate::placeToContainer(
 		SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
@@ -489,7 +488,7 @@ mtpMsgId Connection::placeToContainer(
 	return msgId;
 }
 
-void Connection::tryToSend() {
+void SessionPrivate::tryToSend() {
 	DEBUG_LOG(("MTP Info: tryToSend for dc %1.").arg(_shiftedDcId));
 	if (!_connection) {
 		DEBUG_LOG(("MTP Info: not yet connected in dc %1.").arg(_shiftedDcId));
@@ -591,10 +590,10 @@ void Connection::tryToSend() {
 	MTPInitConnection<SerializedRequest> initWrapper;
 	int32 initSize = 0, initSizeInInts = 0;
 	if (needsLayer) {
-		Assert(_connectionOptions != nullptr);
-		const auto systemLangCode = _connectionOptions->systemLangCode;
-		const auto cloudLangCode = _connectionOptions->cloudLangCode;
-		const auto langPackName = _connectionOptions->langPackName;
+		Assert(_options != nullptr);
+		const auto systemLangCode = _options->systemLangCode;
+		const auto cloudLangCode = _options->cloudLangCode;
+		const auto langPackName = _options->langPackName;
 		const auto deviceModel = (_currentDcType == DcType::Cdn)
 			? "n/a"
 			: _instance->deviceModel();
@@ -610,12 +609,12 @@ void Connection::tryToSend() {
 #else // OS_MAC_STORE || OS_WIN_STORE
 		const auto appVersion = QString::fromLatin1(AppVersionStr);
 #endif // OS_MAC_STORE || OS_WIN_STORE
-		const auto proxyType = _connectionOptions->proxy.type;
+		const auto proxyType = _options->proxy.type;
 		const auto mtprotoProxy = (proxyType == ProxyData::Type::Mtproto);
 		const auto clientProxyFields = mtprotoProxy
 			? MTP_inputClientProxy(
-				MTP_string(_connectionOptions->proxy.host),
-				MTP_int(_connectionOptions->proxy.port))
+				MTP_string(_options->proxy.host),
+				MTP_int(_options->proxy.port))
 			: MTPInputClientProxy();
 		using Flag = MTPInitConnection<SerializedRequest>::Flag;
 		initWrapper = MTPInitConnection<SerializedRequest>(
@@ -720,7 +719,7 @@ void Connection::tryToSend() {
 						auto wrappedRequest = SerializedRequest::Prepare(toSendSize);
 						memcpy(wrappedRequest->data(), toSendRequest->constData(), 7 * sizeof(mtpPrime)); // all except length
 						wrappedRequest->push_back(mtpc_invokeWithLayer);
-						wrappedRequest->push_back(internal::CurrentLayer);
+						wrappedRequest->push_back(kCurrentLayer);
 						initWrapper.write<mtpBuffer>(*wrappedRequest);
 						wrappedRequest->resize(wrappedRequest->size() + noWrapSize);
 						memcpy(wrappedRequest->data() + wrappedRequest->size() - noWrapSize, toSendRequest->constData() + 8, noWrapSize * sizeof(mtpPrime));
@@ -752,7 +751,7 @@ void Connection::tryToSend() {
 			if (willNeedInit) {
 				initSerialized.reserve(initSizeInInts);
 				initSerialized.push_back(mtpc_invokeWithLayer);
-				initSerialized.push_back(internal::CurrentLayer);
+				initSerialized.push_back(kCurrentLayer);
 				initWrapper.write<mtpBuffer>(initSerialized);
 			}
 			// prepare container + each in invoke after
@@ -879,7 +878,7 @@ void Connection::tryToSend() {
 	sendSecureRequest(std::move(toSendRequest), needAnyResponse);
 }
 
-void Connection::retryByTimer() {
+void SessionPrivate::retryByTimer() {
 	if (_retryTimeout < 3) {
 		++_retryTimeout;
 	} else if (_retryTimeout == 3) {
@@ -890,13 +889,13 @@ void Connection::retryByTimer() {
 	connectToServer();
 }
 
-void Connection::restartNow() {
+void SessionPrivate::restartNow() {
 	_retryTimeout = 1;
 	_retryTimer.cancel();
 	restart();
 }
 
-void Connection::connectToServer(bool afterConfig) {
+void SessionPrivate::connectToServer(bool afterConfig) {
 	if (afterConfig && (!_testConnections.empty() || _connection)) {
 		return;
 	}
@@ -908,8 +907,7 @@ void Connection::connectToServer(bool afterConfig) {
 		return;
 	}
 
-	_connectionOptions = std::make_unique<ConnectionOptions>(
-		_sessionData->connectionOptions());
+	_options = std::make_unique<SessionOptions>(_sessionData->options());
 
 	const auto bareDc = BareDcId(_shiftedDcId);
 
@@ -920,7 +918,7 @@ void Connection::connectToServer(bool afterConfig) {
 			return;
 		}
 	}
-	if (_connectionOptions->proxy.type == ProxyData::Type::Mtproto) {
+	if (_options->proxy.type == ProxyData::Type::Mtproto) {
 		// host, port, secret for mtproto proxy are taken from proxy.
 		appendTestConnection(DcOptions::Variants::Tcp, {}, 0, {});
 	} else {
@@ -929,11 +927,11 @@ void Connection::connectToServer(bool afterConfig) {
 		const auto variants = _instance->dcOptions()->lookup(
 			bareDc,
 			_currentDcType,
-			_connectionOptions->proxy.type != ProxyData::Type::None);
-		const auto useIPv4 = special ? true : _connectionOptions->useIPv4;
-		const auto useIPv6 = special ? false : _connectionOptions->useIPv6;
-		const auto useTcp = special ? true : _connectionOptions->useTcp;
-		const auto useHttp = special ? false : _connectionOptions->useHttp;
+			_options->proxy.type != ProxyData::Type::None);
+		const auto useIPv4 = special ? true : _options->useIPv4;
+		const auto useIPv6 = special ? false : _options->useIPv6;
+		const auto useTcp = special ? true : _options->useTcp;
+		const auto useHttp = special ? false : _options->useHttp;
 		const auto skipAddress = !useIPv4
 			? Variants::IPv4
 			: !useIPv6
@@ -1001,7 +999,7 @@ void Connection::connectToServer(bool afterConfig) {
 	_waitForConnectedTimer.callOnce(_waitForConnected);
 }
 
-void Connection::restart() {
+void SessionPrivate::restart() {
 	DEBUG_LOG(("MTP Info: restarting Connection"));
 
 	_waitForReceivedTimer.cancel();
@@ -1021,7 +1019,7 @@ void Connection::restart() {
 	setState(-_retryTimeout);
 }
 
-void Connection::onSentSome(uint64 size) {
+void SessionPrivate::onSentSome(uint64 size) {
 	if (!_waitForReceivedTimer.isActive()) {
 		auto remain = static_cast<uint64>(_waitForReceived);
 		if (!_oldConnection) {
@@ -1042,7 +1040,7 @@ void Connection::onSentSome(uint64 size) {
 	if (!_firstSentAt) _firstSentAt = crl::now();
 }
 
-void Connection::onReceivedSome() {
+void SessionPrivate::onReceivedSome() {
 	if (_oldConnection) {
 		_oldConnection = false;
 		DEBUG_LOG(("This connection marked as not old!"));
@@ -1060,13 +1058,13 @@ void Connection::onReceivedSome() {
 	}
 }
 
-void Connection::markConnectionOld() {
+void SessionPrivate::markConnectionOld() {
 	_oldConnection = true;
 	_waitForReceived = kMinReceiveTimeout;
 	DEBUG_LOG(("This connection marked as old! _waitForReceived now %1ms").arg(_waitForReceived));
 }
 
-void Connection::sendPingByTimer() {
+void SessionPrivate::sendPingByTimer() {
 	if (_pingId) {
 		// _pingSendAt: when to send next ping (lastPingAt + kPingSendAfter)
 		// could be equal to zero.
@@ -1085,7 +1083,7 @@ void Connection::sendPingByTimer() {
 	}
 }
 
-void Connection::sendPingForce() {
+void SessionPrivate::sendPingForce() {
 	DEBUG_LOG(("MTP Info: send ping force for dcWithShift %1.").arg(_shiftedDcId));
 	if (!_pingId) {
 		_pingSendAt = 0;
@@ -1094,10 +1092,10 @@ void Connection::sendPingForce() {
 	}
 }
 
-void Connection::waitReceivedFailed() {
-	Expects(_connectionOptions != nullptr);
+void SessionPrivate::waitReceivedFailed() {
+	Expects(_options != nullptr);
 
-	if (!_connectionOptions->useTcp) {
+	if (!_options->useTcp) {
 		return;
 	}
 
@@ -1114,7 +1112,7 @@ void Connection::waitReceivedFailed() {
 	InvokeQueued(this, [=] { connectToServer(); });
 }
 
-void Connection::waitConnectedFailed() {
+void SessionPrivate::waitConnectedFailed() {
 	DEBUG_LOG(("MTP Info: can't connect in %1ms").arg(_waitForConnected));
 	auto maxTimeout = kMaxConnectedTimeout;
 	for (const auto &connection : _testConnections) {
@@ -1130,29 +1128,29 @@ void Connection::waitConnectedFailed() {
 	InvokeQueued(this, [=] { connectToServer(); });
 }
 
-void Connection::waitBetterFailed() {
+void SessionPrivate::waitBetterFailed() {
 	confirmBestConnection();
 }
 
-void Connection::connectingTimedOut() {
+void SessionPrivate::connectingTimedOut() {
 	for (const auto &connection : _testConnections) {
 		connection.data->timedOut();
 	}
 	doDisconnect();
 }
 
-void Connection::doDisconnect() {
+void SessionPrivate::doDisconnect() {
 	destroyAllConnections();
 	setState(DisconnectedState);
 }
 
-void Connection::requestCDNConfig() {
+void SessionPrivate::requestCDNConfig() {
 	InvokeQueued(_instance, [instance = _instance] {
 		instance->requestCDNConfig();
 	});
 }
 
-void Connection::handleReceived() {
+void SessionPrivate::handleReceived() {
 	Expects(_encryptionKey != nullptr);
 
 	onReceivedSome();
@@ -1303,7 +1301,7 @@ void Connection::handleReceived() {
 		auto end = from + (messageLength / kIntSize);
 		auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
 		MTP_LOG(_shiftedDcId, ("Recv: ")
-			+ details::DumpToText(sfrom, end)
+			+ DumpToText(sfrom, end)
 			+ QString(" (protocolDcId:%1,key:%2)"
 			).arg(getProtocolDcId()
 			).arg(_encryptionKey->keyId()));
@@ -1352,7 +1350,7 @@ void Connection::handleReceived() {
 	}
 }
 
-Connection::HandleResult Connection::handleOneReceived(
+SessionPrivate::HandleResult SessionPrivate::handleOneReceived(
 		const mtpPrime *from,
 		const mtpPrime *end,
 		uint64 msgId,
@@ -1733,7 +1731,7 @@ Connection::HandleResult Connection::handleOneReceived(
 			// the initConnection, so we're not sure yet that it was inited.
 			// Wait till a good response is received.
 		} else {
-			_sessionData->notifyConnectionInited(*_connectionOptions);
+			_sessionData->notifyConnectionInited(*_options);
 		}
 		requestsAcked(ids, true);
 
@@ -1850,7 +1848,7 @@ Connection::HandleResult Connection::handleOneReceived(
 	return HandleResult::Success;
 }
 
-Connection::HandleResult Connection::handleBindResponse(
+SessionPrivate::HandleResult SessionPrivate::handleBindResponse(
 		mtpMsgId requestMsgId,
 		const mtpBuffer &response) {
 	if (!_keyCreator || !_bindMsgId || _bindMsgId != requestMsgId) {
@@ -1878,7 +1876,7 @@ Connection::HandleResult Connection::handleBindResponse(
 	Unexpected("Result of BoundKeyCreator::handleBindResponse.");
 }
 
-mtpBuffer Connection::ungzip(const mtpPrime *from, const mtpPrime *end) const {
+mtpBuffer SessionPrivate::ungzip(const mtpPrime *from, const mtpPrime *end) const {
 	mtpBuffer result; // * 4 because of mtpPrime type
 	result.resize(0);
 
@@ -1930,7 +1928,7 @@ mtpBuffer Connection::ungzip(const mtpPrime *from, const mtpPrime *end) const {
 	return result;
 }
 
-bool Connection::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 serverTime, uint64 serverSalt) {
+bool SessionPrivate::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 serverTime, uint64 serverSalt) {
 	uint32 idsCount = ids.size();
 
 	for (uint32 i = 0; i < idsCount; ++i) {
@@ -1945,7 +1943,7 @@ bool Connection::requestsFixTimeSalt(const QVector<MTPlong> &ids, int32 serverTi
 	return false;
 }
 
-void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
+void SessionPrivate::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 	uint32 idsCount = ids.size();
 
 	DEBUG_LOG(("Message Info: requests acked, ids %1").arg(LogIdsVector(ids)));
@@ -2027,7 +2025,7 @@ void Connection::requestsAcked(const QVector<MTPlong> &ids, bool byResponse) {
 	}
 }
 
-void Connection::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states) {
+void SessionPrivate::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray &states) {
 	const auto idsCount = ids.size();
 	if (!idsCount) {
 		DEBUG_LOG(("Message Info: void ids vector in handleMsgsStates()"));
@@ -2072,7 +2070,7 @@ void Connection::handleMsgsStates(const QVector<MTPlong> &ids, const QByteArray
 	requestsAcked(acked);
 }
 
-void Connection::clearSpecialMsgId(mtpMsgId msgId) {
+void SessionPrivate::clearSpecialMsgId(mtpMsgId msgId) {
 	if (msgId == _pingMsgId) {
 		_pingMsgId = 0;
 		_pingId = 0;
@@ -2081,7 +2079,7 @@ void Connection::clearSpecialMsgId(mtpMsgId msgId) {
 	}
 }
 
-void Connection::resend(
+void SessionPrivate::resend(
 		mtpMsgId msgId,
 		crl::time msCanWait,
 		bool forceContainer) {
@@ -2121,7 +2119,7 @@ void Connection::resend(
 	}
 }
 
-void Connection::resendAll() {
+void SessionPrivate::resendAll() {
 	auto lock = QWriteLocker(_sessionData->haveSentMutex());
 	auto haveSent = base::take(_sessionData->haveSentMap());
 	lock.unlock();
@@ -2141,7 +2139,7 @@ void Connection::resendAll() {
 	_sessionData->queueSendAnything();
 }
 
-void Connection::onConnected(
+void SessionPrivate::onConnected(
 		not_null<AbstractConnection*> connection) {
 	disconnect(connection, &AbstractConnection::connected, nullptr, nullptr);
 	if (!connection->isConnected()) {
@@ -2175,7 +2173,7 @@ void Connection::onConnected(
 	}
 }
 
-void Connection::onDisconnected(
+void SessionPrivate::onDisconnected(
 		not_null<AbstractConnection*> connection) {
 	removeTestConnection(connection);
 
@@ -2187,7 +2185,7 @@ void Connection::onDisconnected(
 	}
 }
 
-void Connection::confirmBestConnection() {
+void SessionPrivate::confirmBestConnection() {
 	if (_waitForBetterTimer.isActive()) {
 		return;
 	}
@@ -2211,7 +2209,7 @@ void Connection::confirmBestConnection() {
 	checkAuthKey();
 }
 
-void Connection::removeTestConnection(
+void SessionPrivate::removeTestConnection(
 		not_null<AbstractConnection*> connection) {
 	_testConnections.erase(
 		ranges::remove(
@@ -2221,7 +2219,7 @@ void Connection::removeTestConnection(
 		end(_testConnections));
 }
 
-void Connection::checkAuthKey() {
+void SessionPrivate::checkAuthKey() {
 	if (_keyId) {
 		authKeyChecked();
 	} else if (_instance->isKeysDestroyer()) {
@@ -2232,7 +2230,7 @@ void Connection::checkAuthKey() {
 	}
 }
 
-void Connection::updateAuthKey() {
+void SessionPrivate::updateAuthKey() {
 	if (_instance->isKeysDestroyer() || _keyCreator || !_connection) {
 		return;
 	}
@@ -2250,7 +2248,7 @@ void Connection::updateAuthKey() {
 	}
 }
 
-void Connection::setCurrentKeyId(uint64 newKeyId) {
+void SessionPrivate::setCurrentKeyId(uint64 newKeyId) {
 	if (_keyId == newKeyId) {
 		return;
 	}
@@ -2260,7 +2258,7 @@ void Connection::setCurrentKeyId(uint64 newKeyId) {
 	changeSessionId();
 }
 
-void Connection::applyAuthKey(AuthKeyPtr &&encryptionKey) {
+void SessionPrivate::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 	_encryptionKey = std::move(encryptionKey);
 	const auto newKeyId = _encryptionKey ? _encryptionKey->keyId() : 0;
 	if (_keyId) {
@@ -2302,7 +2300,7 @@ void Connection::applyAuthKey(AuthKeyPtr &&encryptionKey) {
 	}
 }
 
-bool Connection::destroyOldEnoughPersistentKey() {
+bool SessionPrivate::destroyOldEnoughPersistentKey() {
 	Expects(_keyCreator != nullptr);
 
 	const auto key = _keyCreator->bindPersistentKey();
@@ -2321,7 +2319,7 @@ bool Connection::destroyOldEnoughPersistentKey() {
 	return true;
 }
 
-DcType Connection::tryAcquireKeyCreation() {
+DcType SessionPrivate::tryAcquireKeyCreation() {
 	if (_keyCreator) {
 		return _currentDcType;
 	} else if (_instance->isKeysDestroyer()) {
@@ -2395,7 +2393,7 @@ DcType Connection::tryAcquireKeyCreation() {
 	return forceUseRegular ? DcType::Regular : _realDcType;
 }
 
-void Connection::authKeyChecked() {
+void SessionPrivate::authKeyChecked() {
 	connect(_connection, &AbstractConnection::receivedData, [=] {
 		handleReceived();
 	});
@@ -2408,7 +2406,7 @@ void Connection::authKeyChecked() {
 	_sessionData->queueNeedToResumeAndSend();
 }
 
-void Connection::onError(
+void SessionPrivate::onError(
 		not_null<AbstractConnection*> connection,
 		qint32 errorCode) {
 	if (errorCode == -429) {
@@ -2428,7 +2426,7 @@ void Connection::onError(
 	}
 }
 
-void Connection::handleError(int errorCode) {
+void SessionPrivate::handleError(int errorCode) {
 	destroyAllConnections();
 	_waitForConnectedTimer.cancel();
 
@@ -2440,7 +2438,7 @@ void Connection::handleError(int errorCode) {
 	}
 }
 
-void Connection::destroyTemporaryKey() {
+void SessionPrivate::destroyTemporaryKey() {
 	if (_instance->isKeysDestroyer()) {
 		LOG(("MTP Info: -404 error received in destroyer %1, assuming key was destroyed.").arg(_shiftedDcId));
 		_instance->keyWasPossiblyDestroyed(_shiftedDcId);
@@ -2455,7 +2453,7 @@ void Connection::destroyTemporaryKey() {
 	restart();
 }
 
-bool Connection::sendSecureRequest(
+bool SessionPrivate::sendSecureRequest(
 		SerializedRequest &&request,
 		bool needAnyResponse) {
 #ifdef TDESKTOP_MTPROTO_OLD
@@ -2480,7 +2478,7 @@ bool Connection::sendSecureRequest(
 
 	auto from = request->constData() + 4;
 	MTP_LOG(_shiftedDcId, ("Send: ")
-		+ details::DumpToText(from, from + messageSize)
+		+ DumpToText(from, from + messageSize)
 		+ QString(" (protocolDcId:%1,key:%2)"
 		).arg(getProtocolDcId()
 		).arg(_encryptionKey->keyId()));
@@ -2539,7 +2537,7 @@ bool Connection::sendSecureRequest(
 	return true;
 }
 
-mtpRequestId Connection::wasSent(mtpMsgId msgId) const {
+mtpRequestId SessionPrivate::wasSent(mtpMsgId msgId) const {
 	if (msgId == _pingMsgId || msgId == _bindMsgId) {
 		return mtpRequestId(0xFFFFFFFF);
 	}
@@ -2566,13 +2564,13 @@ mtpRequestId Connection::wasSent(mtpMsgId msgId) const {
 	return 0;
 }
 
-void Connection::clearUnboundKeyCreator() {
+void SessionPrivate::clearUnboundKeyCreator() {
 	if (_keyCreator) {
 		_keyCreator->stop();
 	}
 }
 
-void Connection::releaseKeyCreationOnFail() {
+void SessionPrivate::releaseKeyCreationOnFail() {
 	if (!_keyCreator) {
 		return;
 	}
@@ -2580,5 +2578,5 @@ void Connection::releaseKeyCreationOnFail() {
 	_sessionData->releaseKeyCreationOnFail();
 }
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/connection.h b/Telegram/SourceFiles/mtproto/session_private.h
similarity index 89%
rename from Telegram/SourceFiles/mtproto/connection.h
rename to Telegram/SourceFiles/mtproto/session_private.h
index 67b898f48..fcc32c704 100644
--- a/Telegram/SourceFiles/mtproto/connection.h
+++ b/Telegram/SourceFiles/mtproto/session_private.h
@@ -21,26 +21,23 @@ namespace details {
 class BoundKeyCreator;
 } // namespace details
 
-// How much time to wait for some more requests, when sending msg acks.
-constexpr auto kAckSendWaiting = 10 * crl::time(1000);
-
 class Instance;
 
-namespace internal {
+namespace details {
 
 class AbstractConnection;
 class SessionData;
 class RSAPublicKey;
-struct ConnectionOptions;
+struct SessionOptions;
 
-class Connection : public QObject {
+class SessionPrivate final : public QObject {
 public:
-	Connection(
+	SessionPrivate(
 		not_null<Instance*> instance,
 		not_null<QThread*> thread,
 		std::shared_ptr<SessionData> data,
 		ShiftedDcId shiftedDcId);
-	~Connection();
+	~SessionPrivate();
 
 	[[nodiscard]] int32 getShiftedDcId() const;
 	void dcOptionsChanged();
@@ -106,20 +103,20 @@ private:
 	void clearOldContainers();
 
 	mtpMsgId placeToContainer(
-		details::SerializedRequest &toSendRequest,
+		SerializedRequest &toSendRequest,
 		mtpMsgId &bigMsgId,
 		bool forceNewMsgId,
-		details::SerializedRequest &req);
+		SerializedRequest &req);
 	mtpMsgId prepareToSend(
-		details::SerializedRequest &request,
+		SerializedRequest &request,
 		mtpMsgId currentLastId,
 		bool forceNewMsgId);
 	mtpMsgId replaceMsgId(
-		details::SerializedRequest &request,
+		SerializedRequest &request,
 		mtpMsgId newId);
 
 	bool sendSecureRequest(
-		details::SerializedRequest &&request,
+		SerializedRequest &&request,
 		bool needAnyResponse);
 	mtpRequestId wasSent(mtpMsgId msgId) const;
 
@@ -205,7 +202,7 @@ private:
 	base::Timer _checkSentRequestsTimer;
 
 	std::shared_ptr<SessionData> _sessionData;
-	std::unique_ptr<ConnectionOptions> _connectionOptions;
+	std::unique_ptr<SessionOptions> _options;
 	AuthKeyPtr _encryptionKey;
 	uint64 _keyId = 0;
 	uint64 _sessionId = 0;
@@ -216,16 +213,16 @@ private:
 	QVector<MTPlong> _ackRequestData;
 	QVector<MTPlong> _resendRequestData;
 	base::flat_set<mtpMsgId> _stateRequestData;
-	details::ReceivedIdsManager _receivedMessageIds;
+	ReceivedIdsManager _receivedMessageIds;
 	base::flat_map<mtpMsgId, mtpRequestId> _resendingIds;
 	base::flat_map<mtpMsgId, mtpRequestId> _ackedIds;
-	base::flat_map<mtpMsgId, details::SerializedRequest> _stateAndResendRequests;
+	base::flat_map<mtpMsgId, SerializedRequest> _stateAndResendRequests;
 	base::flat_map<mtpMsgId, SentContainer> _sentContainers;
 
-	std::unique_ptr<details::BoundKeyCreator> _keyCreator;
+	std::unique_ptr<BoundKeyCreator> _keyCreator;
 	mtpMsgId _bindMsgId = 0;
 
 };
 
-} // namespace internal
+} // namespace details
 } // namespace MTP
diff --git a/Telegram/SourceFiles/mtproto/special_config_request.cpp b/Telegram/SourceFiles/mtproto/special_config_request.cpp
index 992c436c6..29f0fc7ee 100644
--- a/Telegram/SourceFiles/mtproto/special_config_request.cpp
+++ b/Telegram/SourceFiles/mtproto/special_config_request.cpp
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "mtproto/special_config_request.h"
 
-#include "mtproto/mtproto_rsa_public_key.h"
+#include "mtproto/details/mtproto_rsa_public_key.h"
 #include "mtproto/dc_options.h"
 #include "mtproto/mtproto_auth_key.h"
 #include "base/unixtime.h"
@@ -19,16 +19,10 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtCore/QJsonArray>
 #include <QtCore/QJsonObject>
 
-extern "C" {
-#include <openssl/aes.h>
-} // extern "C"
-
-namespace MTP {
+namespace MTP::details {
 namespace {
 
 constexpr auto kSendNextTimeout = crl::time(800);
-constexpr auto kMinTimeToLive = 10 * crl::time(1000);
-constexpr auto kMaxTimeToLive = 300 * crl::time(1000);
 
 constexpr auto kPublicKey = str_const("\
 -----BEGIN RSA PUBLIC KEY-----\n\
@@ -41,9 +35,6 @@ Y1hZCxdv6cs5UnW9+PWvS+WIbkh+GaWYxwIDAQAB\n\
 -----END RSA PUBLIC KEY-----\
 ");
 
-constexpr auto kUserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
-"AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.90 Safari/537.36";
-
 const auto kRemoteProject = "peak-vista-421";
 const auto kFireProject = "reserve-5a846";
 const auto kConfigKey = "ipconfig";
@@ -51,21 +42,6 @@ const auto kConfigSubKey = "v3";
 const auto kApiKey = "AIzaSyC2-kAkpDsroixRXw-sTw-Wfqo4NxjMwwM";
 const auto kAppId = "1:560508485281:web:4ee13a6af4e84d49e67ae0";
 
-struct DnsEntry {
-	QString data;
-	crl::time TTL = 0;
-};
-
-const std::vector<QString> &DnsDomains() {
-	static auto result = std::vector<QString>{
-		qsl("google.com"),
-		qsl("www.google.com"),
-		qsl("google.ru"),
-		qsl("www.google.ru"),
-	};
-	return result;
-}
-
 QString ApiDomain(const QString &service) {
 	return service + ".googleapis.com";
 }
@@ -103,99 +79,6 @@ bool CheckPhoneByPrefixesRules(const QString &phone, const QString &rules) {
 	return result;
 }
 
-QString GenerateRandomPadding() {
-	constexpr char kValid[] = "abcdefghijklmnopqrstuvwxyz"
-		"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-
-	auto result = QString();
-	const auto count = [&] {
-		constexpr auto kMinPadding = 13;
-		constexpr auto kMaxPadding = 128;
-		while (true) {
-			const auto result = 1 + (rand_value<uchar>() / 2);
-			Assert(result <= kMaxPadding);
-			if (result >= kMinPadding) {
-				return result;
-			}
-		}
-	}();
-	result.resize(count);
-	for (auto &ch : result) {
-		ch = kValid[rand_value<uchar>() % (sizeof(kValid) - 1)];
-	}
-	return result;
-}
-
-std::vector<DnsEntry> ParseDnsResponse(
-		const QByteArray &bytes,
-		std::optional<int> typeRestriction = std::nullopt) {
-	// Read and store to "result" all the data bytes from the response:
-	// { ..,
-	//   "Answer": [
-	//     { .., "data": "bytes1", "TTL": int, .. },
-	//     { .., "data": "bytes2", "TTL": int, .. }
-	//   ],
-	// .. }
-	auto error = QJsonParseError{ 0, QJsonParseError::NoError };
-	const auto document = QJsonDocument::fromJson(bytes, &error);
-	if (error.error != QJsonParseError::NoError) {
-		LOG(("Config Error: Failed to parse dns response JSON, error: %1"
-			).arg(error.errorString()));
-		return {};
-	} else if (!document.isObject()) {
-		LOG(("Config Error: Not an object received in dns response JSON."));
-		return {};
-	}
-	const auto response = document.object();
-	const auto answerIt = response.find(qsl("Answer"));
-	if (answerIt == response.constEnd()) {
-		LOG(("Config Error: Could not find Answer in dns response JSON."));
-		return {};
-	} else if (!(*answerIt).isArray()) {
-		LOG(("Config Error: Not an array received "
-			"in Answer in dns response JSON."));
-		return {};
-	}
-
-	auto result = std::vector<DnsEntry>();
-	for (const auto elem : (*answerIt).toArray()) {
-		if (!elem.isObject()) {
-			LOG(("Config Error: Not an object found "
-				"in Answer array in dns response JSON."));
-			continue;
-		}
-		const auto object = elem.toObject();
-		if (typeRestriction) {
-			const auto typeIt = object.find(qsl("type"));
-			const auto type = int(std::round((*typeIt).toDouble()));
-			if (!(*typeIt).isDouble()) {
-				LOG(("Config Error: Not a number in type field "
-					"in Answer array in dns response JSON."));
-				continue;
-			} else if (type != *typeRestriction) {
-				continue;
-			}
-		}
-		const auto dataIt = object.find(qsl("data"));
-		if (dataIt == object.constEnd()) {
-			LOG(("Config Error: Could not find data "
-				"in Answer array entry in dns response JSON."));
-			continue;
-		} else if (!(*dataIt).isString()) {
-			LOG(("Config Error: Not a string data found "
-				"in Answer array entry in dns response JSON."));
-			continue;
-		}
-
-		const auto ttlIt = object.find(qsl("TTL"));
-		const auto ttl = (ttlIt != object.constEnd())
-			? crl::time(std::round((*ttlIt).toDouble()))
-			: crl::time(0);
-		result.push_back({ (*dataIt).toString(), ttl });
-	}
-	return result;
-}
-
 QByteArray ConcatenateDnsTxtFields(const std::vector<DnsEntry> &response) {
 	auto entries = QMap<int, QString>();
 	for (const auto &entry : response) {
@@ -299,40 +182,6 @@ QByteArray ParseRealtimeResponse(const QByteArray &bytes) {
 
 } // namespace
 
-ServiceWebRequest::ServiceWebRequest(not_null<QNetworkReply*> reply)
-: reply(reply.get()) {
-}
-
-ServiceWebRequest::ServiceWebRequest(ServiceWebRequest &&other)
-: reply(base::take(other.reply)) {
-}
-
-ServiceWebRequest &ServiceWebRequest::operator=(ServiceWebRequest &&other) {
-	if (reply != other.reply) {
-		destroy();
-		reply = base::take(other.reply);
-	}
-	return *this;
-}
-
-void ServiceWebRequest::destroy() {
-	if (const auto value = base::take(reply)) {
-		value->disconnect(
-			value,
-			&QNetworkReply::finished,
-			nullptr,
-			nullptr);
-		value->abort();
-		value->deleteLater();
-	}
-}
-
-ServiceWebRequest::~ServiceWebRequest() {
-	if (reply) {
-		reply->deleteLater();
-	}
-}
-
 SpecialConfigRequest::SpecialConfigRequest(
 	Fn<void(
 		DcId dcId,
@@ -435,7 +284,7 @@ void SpecialConfigRequest::performRequest(const Attempt &attempt) {
 		url.setPath(qsl("/dns-query"));
 		url.setQuery(qsl("name=%1&type=16&random_padding=%2"
 		).arg(Global::TxtDomainString()
-		).arg(GenerateRandomPadding()));
+		).arg(GenerateDnsRandomPadding()));
 		request.setRawHeader("accept", "application/dns-json");
 	} break;
 	case Type::Google: {
@@ -443,7 +292,7 @@ void SpecialConfigRequest::performRequest(const Attempt &attempt) {
 		url.setPath(qsl("/resolve"));
 		url.setQuery(qsl("name=%1&type=ANY&random_padding=%2"
 		).arg(Global::TxtDomainString()
-		).arg(GenerateRandomPadding()));
+		).arg(GenerateDnsRandomPadding()));
 		if (!attempt.host.isEmpty()) {
 			const auto host = attempt.host + ".google.com";
 			request.setRawHeader("Host", host.toLatin1());
@@ -479,7 +328,7 @@ void SpecialConfigRequest::performRequest(const Attempt &attempt) {
 	default: Unexpected("Type in SpecialConfigRequest::performRequest.");
 	}
 	request.setUrl(url);
-	request.setRawHeader("User-Agent", kUserAgent);
+	request.setRawHeader("User-Agent", DnsUserAgent());
 	const auto reply = _requests.emplace_back(payload.isEmpty()
 		? _manager.get(request)
 		: _manager.post(request, payload)
@@ -587,7 +436,7 @@ bool SpecialConfigRequest::decryptSimpleConfig(const QByteArray &bytes) {
 		return false;
 	}
 
-	auto publicKey = internal::RSAPublicKey(bytes::make_span(
+	auto publicKey = details::RSAPublicKey(bytes::make_span(
 		kPublicKey.c_str(),
 		kPublicKey.size()));
 	auto decrypted = publicKey.decrypt(bytes::make_span(decodedBytes));
@@ -693,190 +542,4 @@ void SpecialConfigRequest::handleResponse(const QByteArray &bytes) {
 	_callback(0, std::string(), 0, {});
 }
 
-DomainResolver::DomainResolver(Fn<void(
-	const QString &host,
-	const QStringList &ips,
-	crl::time expireAt)> callback)
-: _callback(std::move(callback)) {
-	_manager.setProxy(QNetworkProxy::NoProxy);
-}
-
-void DomainResolver::resolve(const QString &domain) {
-	resolve({ domain, false });
-	resolve({ domain, true });
-}
-
-void DomainResolver::resolve(const AttemptKey &key) {
-	if (_attempts.find(key) != end(_attempts)) {
-		return;
-	} else if (_requests.find(key) != end(_requests)) {
-		return;
-	}
-	const auto i = _cache.find(key);
-	_lastTimestamp = crl::now();
-	if (i != end(_cache) && i->second.expireAt > _lastTimestamp) {
-		checkExpireAndPushResult(key.domain);
-		return;
-	}
-
-	auto attempts = std::vector<Attempt>();
-	auto domains = DnsDomains();
-	std::random_device rd;
-	ranges::shuffle(domains, std::mt19937(rd()));
-	const auto takeDomain = [&] {
-		const auto result = domains.back();
-		domains.pop_back();
-		return result;
-	};
-	const auto shuffle = [&](int from, int till) {
-		Expects(till > from);
-
-		ranges::shuffle(
-			begin(attempts) + from,
-			begin(attempts) + till,
-			std::mt19937(rd()));
-	};
-
-	attempts.push_back({ Type::Google, "dns.google.com" });
-	attempts.push_back({ Type::Google, takeDomain(), "dns" });
-	attempts.push_back({ Type::Mozilla, "mozilla.cloudflare-dns.com" });
-	while (!domains.empty()) {
-		attempts.push_back({ Type::Google, takeDomain(), "dns" });
-	}
-
-	shuffle(0, 2);
-
-	ranges::reverse(attempts); // We go from last to first.
-
-	_attempts.emplace(key, Attempts{ std::move(attempts) });
-	sendNextRequest(key);
-}
-
-void DomainResolver::checkExpireAndPushResult(const QString &domain) {
-	const auto ipv4 = _cache.find({ domain, false });
-	if (ipv4 == end(_cache) || ipv4->second.expireAt <= _lastTimestamp) {
-		return;
-	}
-	auto result = ipv4->second;
-	const auto ipv6 = _cache.find({ domain, true });
-	if (ipv6 != end(_cache) && ipv6->second.expireAt > _lastTimestamp) {
-		result.ips.append(ipv6->second.ips);
-		accumulate_min(result.expireAt, ipv6->second.expireAt);
-	}
-	InvokeQueued(this, [=] {
-		_callback(domain, result.ips, result.expireAt);
-	});
-}
-
-void DomainResolver::sendNextRequest(const AttemptKey &key) {
-	auto i = _attempts.find(key);
-	if (i == end(_attempts)) {
-		return;
-	}
-	auto &attempts = i->second;
-	auto &list = attempts.list;
-	const auto attempt = list.back();
-	list.pop_back();
-
-	if (!list.empty()) {
-		base::call_delayed(kSendNextTimeout, &attempts.guard, [=] {
-			sendNextRequest(key);
-		});
-	}
-	performRequest(key, attempt);
-}
-
-void DomainResolver::performRequest(
-		const AttemptKey &key,
-		const Attempt &attempt) {
-	auto url = QUrl();
-	url.setScheme(qsl("https"));
-	auto request = QNetworkRequest();
-	switch (attempt.type) {
-	case Type::Mozilla: {
-		url.setHost(attempt.data);
-		url.setPath(qsl("/dns-query"));
-		url.setQuery(qsl("name=%1&type=%2&random_padding=%3"
-		).arg(key.domain
-		).arg(key.ipv6 ? 28 : 1
-		).arg(GenerateRandomPadding()));
-		request.setRawHeader("accept", "application/dns-json");
-	} break;
-	case Type::Google: {
-		url.setHost(attempt.data);
-		url.setPath(qsl("/resolve"));
-		url.setQuery(qsl("name=%1&type=%2&random_padding=%3"
-		).arg(key.domain
-		).arg(key.ipv6 ? 28 : 1
-		).arg(GenerateRandomPadding()));
-		if (!attempt.host.isEmpty()) {
-			const auto host = attempt.host + ".google.com";
-			request.setRawHeader("Host", host.toLatin1());
-		}
-	} break;
-	default: Unexpected("Type in SpecialConfigRequest::performRequest.");
-	}
-	request.setUrl(url);
-	request.setRawHeader("User-Agent", kUserAgent);
-	const auto i = _requests.emplace(
-		key,
-		std::vector<ServiceWebRequest>()).first;
-	const auto reply = i->second.emplace_back(
-		_manager.get(request)
-	).reply;
-	connect(reply, &QNetworkReply::finished, this, [=] {
-		requestFinished(key, reply);
-	});
-}
-
-void DomainResolver::requestFinished(
-		const AttemptKey &key,
-		not_null<QNetworkReply*> reply) {
-	const auto result = finalizeRequest(key, reply);
-	const auto response = ParseDnsResponse(result);
-	if (response.empty()) {
-		return;
-	}
-	_requests.erase(key);
-	_attempts.erase(key);
-
-	auto entry = CacheEntry();
-	auto ttl = kMaxTimeToLive;
-	for (const auto &item : response) {
-		entry.ips.push_back(item.data);
-		accumulate_min(ttl, std::max(
-			item.TTL * crl::time(1000),
-			kMinTimeToLive));
-	}
-	_lastTimestamp = crl::now();
-	entry.expireAt = _lastTimestamp + ttl;
-	_cache[key] = std::move(entry);
-
-	checkExpireAndPushResult(key.domain);
-}
-
-QByteArray DomainResolver::finalizeRequest(
-		const AttemptKey &key,
-		not_null<QNetworkReply*> reply) {
-	if (reply->error() != QNetworkReply::NoError) {
-		LOG(("Resolve Error: Failed to get response, error: %2 (%3)"
-			).arg(reply->errorString()
-			).arg(reply->error()));
-	}
-	const auto result = reply->readAll();
-	const auto i = _requests.find(key);
-	if (i != end(_requests)) {
-		auto &requests = i->second;
-		const auto from = ranges::remove(
-			requests,
-			reply,
-			[](const ServiceWebRequest &request) { return request.reply; });
-		requests.erase(from, end(requests));
-		if (requests.empty()) {
-			_requests.erase(i);
-		}
-	}
-	return result;
-}
-
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/mtproto/special_config_request.h b/Telegram/SourceFiles/mtproto/special_config_request.h
index 7826c66b1..da4d27f4d 100644
--- a/Telegram/SourceFiles/mtproto/special_config_request.h
+++ b/Telegram/SourceFiles/mtproto/special_config_request.h
@@ -7,24 +7,15 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
+#include "mtproto/details/mtproto_domain_resolver.h"
 #include "base/bytes.h"
+#include "base/weak_ptr.h"
 
+#include <QtCore/QPointer>
 #include <QtNetwork/QNetworkReply>
 #include <QtNetwork/QNetworkAccessManager>
 
-namespace MTP {
-
-struct ServiceWebRequest {
-    ServiceWebRequest(not_null<QNetworkReply*> reply);
-    ServiceWebRequest(ServiceWebRequest &&other);
-    ServiceWebRequest &operator=(ServiceWebRequest &&other);
-    ~ServiceWebRequest();
-
-    void destroy();
-
-    QPointer<QNetworkReply> reply;
-
-};
+namespace MTP::details {
 
 class SpecialConfigRequest : public QObject {
 public:
@@ -83,71 +74,4 @@ private:
 
 };
 
-class DomainResolver : public QObject {
-public:
-	DomainResolver(Fn<void(
-		const QString &domain,
-		const QStringList &ips,
-		crl::time expireAt)> callback);
-
-	void resolve(const QString &domain);
-
-private:
-	enum class Type {
-		Mozilla,
-		Google,
-	};
-	struct Attempt {
-		Type type;
-		QString data;
-		QString host;
-	};
-	struct AttemptKey {
-		QString domain;
-		bool ipv6 = false;
-
-		inline bool operator<(const AttemptKey &other) const {
-			return (domain < other.domain)
-				|| (domain == other.domain && !ipv6 && other.ipv6);
-		}
-		inline bool operator==(const AttemptKey &other) const {
-			return (domain == other.domain) && (ipv6 == other.ipv6);
-		}
-
-	};
-	struct CacheEntry {
-		QStringList ips;
-		crl::time expireAt = 0;
-
-	};
-	struct Attempts {
-		std::vector<Attempt> list;
-		base::has_weak_ptr guard;
-
-	};
-
-	void resolve(const AttemptKey &key);
-	void sendNextRequest(const AttemptKey &key);
-	void performRequest(const AttemptKey &key, const Attempt &attempt);
-	void checkExpireAndPushResult(const QString &domain);
-	void requestFinished(
-		const AttemptKey &key,
-		not_null<QNetworkReply*> reply);
-	QByteArray finalizeRequest(
-		const AttemptKey &key,
-		not_null<QNetworkReply*> reply);
-
-	Fn<void(
-		const QString &domain,
-		const QStringList &ips,
-		crl::time expireAt)> _callback;
-
-	QNetworkAccessManager _manager;
-	std::map<AttemptKey, Attempts> _attempts;
-	std::map<AttemptKey, std::vector<ServiceWebRequest>> _requests;
-	std::map<AttemptKey, CacheEntry> _cache;
-	crl::time _lastTimestamp = 0;
-
-};
-
-} // namespace MTP
+} // namespace MTP::details
diff --git a/Telegram/SourceFiles/passport/passport_encryption.cpp b/Telegram/SourceFiles/passport/passport_encryption.cpp
index ce83fa5d8..4d9b3520e 100644
--- a/Telegram/SourceFiles/passport/passport_encryption.cpp
+++ b/Telegram/SourceFiles/passport/passport_encryption.cpp
@@ -8,7 +8,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "passport/passport_encryption.h"
 
 #include "base/openssl_help.h"
-#include "mtproto/mtproto_rsa_public_key.h"
+#include "mtproto/details/mtproto_rsa_public_key.h"
 
 #include <QtCore/QJsonDocument>
 #include <QtCore/QJsonArray>
@@ -429,7 +429,7 @@ uint64 CountSecureSecretId(bytes::const_span secret) {
 bytes::vector EncryptCredentialsSecret(
 		bytes::const_span secret,
 		bytes::const_span publicKey) {
-	const auto key = MTP::internal::RSAPublicKey(publicKey);
+	const auto key = MTP::details::RSAPublicKey(publicKey);
 	return key.encryptOAEPpadding(secret);
 }
 
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index ae046b0d4..e56544935 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -15,7 +15,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/application.h"
 #include "storage/localstorage.h"
 #include "platform/platform_file_utilities.h"
-#include "mtproto/connection.h" // for MTP::kAckSendWaiting
 #include "main/main_session.h"
 #include "apiwrap.h"
 #include "core/crash_reports.h"
@@ -28,7 +27,7 @@ namespace Storage {
 namespace {
 
 // How much time without download causes additional session kill.
-constexpr auto kKillSessionTimeout = crl::time(5000);
+constexpr auto kKillSessionTimeout = 15 * crl::time(1000);
 
 // Max 16 file parts downloaded at the same time, 128 KB each.
 constexpr auto kMaxFileQueries = 16;
@@ -75,11 +74,10 @@ void Downloader::killDownloadSessionsStart(MTP::DcId dcId) {
 	if (!_killDownloadSessionTimes.contains(dcId)) {
 		_killDownloadSessionTimes.emplace(
 			dcId,
-			crl::now() + MTP::kAckSendWaiting + kKillSessionTimeout);
+			crl::now() + kKillSessionTimeout);
 	}
 	if (!_killDownloadSessionsTimer.isActive()) {
-		_killDownloadSessionsTimer.callOnce(
-			MTP::kAckSendWaiting + kKillSessionTimeout + 5);
+		_killDownloadSessionsTimer.callOnce(kKillSessionTimeout + 5);
 	}
 }
 
@@ -92,16 +90,17 @@ void Downloader::killDownloadSessionsStop(MTP::DcId dcId) {
 }
 
 void Downloader::killDownloadSessions() {
-	auto ms = crl::now(), left = MTP::kAckSendWaiting + kKillSessionTimeout;
+	const auto now = crl::now();
+	auto left = kKillSessionTimeout;
 	for (auto i = _killDownloadSessionTimes.begin(); i != _killDownloadSessionTimes.end(); ) {
-		if (i->second <= ms) {
+		if (i->second <= now) {
 			for (int j = 0; j < MTP::kDownloadSessionsCount; ++j) {
 				MTP::stopSession(MTP::downloadDcId(i->first, j));
 			}
 			i = _killDownloadSessionTimes.erase(i);
 		} else {
-			if (i->second - ms < left) {
-				left = i->second - ms;
+			if (i->second - now < left) {
+				left = i->second - now;
 			}
 			++i;
 		}
diff --git a/Telegram/SourceFiles/storage/file_upload.cpp b/Telegram/SourceFiles/storage/file_upload.cpp
index 6d852cdb9..4263328fd 100644
--- a/Telegram/SourceFiles/storage/file_upload.cpp
+++ b/Telegram/SourceFiles/storage/file_upload.cpp
@@ -9,7 +9,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "storage/localimageloader.h"
 #include "storage/file_download.h"
-#include "mtproto/connection.h" // for MTP::kAckSendWaiting
 #include "data/data_document.h"
 #include "data/data_photo.h"
 #include "data/data_session.h"
@@ -42,7 +41,7 @@ constexpr auto kDocumentUploadPartSize4 = 512 * 1024;
 constexpr auto kUploadRequestInterval = crl::time(500);
 
 // How much time without upload causes additional session kill.
-constexpr auto kKillSessionTimeout = crl::time(5000);
+constexpr auto kKillSessionTimeout = 15 * crl::time(000);
 
 } // namespace
 
@@ -256,8 +255,7 @@ void Uploader::sendNext() {
 	bool stopping = stopSessionsTimer.isActive();
 	if (queue.empty()) {
 		if (!stopping) {
-			stopSessionsTimer.start(
-				MTP::kAckSendWaiting + kKillSessionTimeout);
+			stopSessionsTimer.start(kKillSessionTimeout);
 		}
 		return;
 	}
diff --git a/Telegram/gyp/lib_mtproto.gyp b/Telegram/gyp/lib_mtproto.gyp
index f95b4310d..5ca1ad191 100644
--- a/Telegram/gyp/lib_mtproto.gyp
+++ b/Telegram/gyp/lib_mtproto.gyp
@@ -34,34 +34,40 @@
       '<(src_loc)',
     ],
     'sources': [
+      '<(src_loc)/mtproto/details/mtproto_abstract_socket.cpp',
+      '<(src_loc)/mtproto/details/mtproto_abstract_socket.h',
       '<(src_loc)/mtproto/details/mtproto_bound_key_creator.cpp',
       '<(src_loc)/mtproto/details/mtproto_bound_key_creator.h',
       '<(src_loc)/mtproto/details/mtproto_dc_key_binder.cpp',
       '<(src_loc)/mtproto/details/mtproto_dc_key_binder.h',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.cpp',
       '<(src_loc)/mtproto/details/mtproto_dc_key_creator.h',
+      '<(src_loc)/mtproto/details/mtproto_dcenter.cpp',
+      '<(src_loc)/mtproto/details/mtproto_dcenter.h',
+      '<(src_loc)/mtproto/details/mtproto_domain_resolver.cpp',
+      '<(src_loc)/mtproto/details/mtproto_domain_resolver.h',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.cpp',
       '<(src_loc)/mtproto/details/mtproto_dump_to_text.h',
       '<(src_loc)/mtproto/details/mtproto_received_ids_manager.cpp',
       '<(src_loc)/mtproto/details/mtproto_received_ids_manager.h',
+      '<(src_loc)/mtproto/details/mtproto_rsa_public_key.cpp',
+      '<(src_loc)/mtproto/details/mtproto_rsa_public_key.h',
       '<(src_loc)/mtproto/details/mtproto_serialized_request.cpp',
       '<(src_loc)/mtproto/details/mtproto_serialized_request.h',
-      '<(src_loc)/mtproto/mtproto_abstract_socket.cpp',
-      '<(src_loc)/mtproto/mtproto_abstract_socket.h',
+      '<(src_loc)/mtproto/details/mtproto_tcp_socket.cpp',
+      '<(src_loc)/mtproto/details/mtproto_tcp_socket.h',
+      '<(src_loc)/mtproto/details/mtproto_tls_socket.cpp',
+      '<(src_loc)/mtproto/details/mtproto_tls_socket.h',
       '<(src_loc)/mtproto/mtproto_auth_key.cpp',
       '<(src_loc)/mtproto/mtproto_auth_key.h',
+      '<(src_loc)/mtproto/mtproto_concurrent_sender.cpp',
+      '<(src_loc)/mtproto/mtproto_concurrent_sender.h',
       '<(src_loc)/mtproto/mtproto_dh_utils.cpp',
       '<(src_loc)/mtproto/mtproto_dh_utils.h',
       '<(src_loc)/mtproto/mtproto_proxy_data.cpp',
       '<(src_loc)/mtproto/mtproto_proxy_data.h',
-      '<(src_loc)/mtproto/mtproto_rsa_public_key.cpp',
-      '<(src_loc)/mtproto/mtproto_rsa_public_key.h',
       '<(src_loc)/mtproto/mtproto_rpc_sender.cpp',
       '<(src_loc)/mtproto/mtproto_rpc_sender.h',
-      '<(src_loc)/mtproto/mtproto_tcp_socket.cpp',
-      '<(src_loc)/mtproto/mtproto_tcp_socket.h',
-      '<(src_loc)/mtproto/mtproto_tls_socket.cpp',
-      '<(src_loc)/mtproto/mtproto_tls_socket.h',
     ],
   }],
 }
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index c4d81714e..6276efafc 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -537,12 +537,8 @@
 <(src_loc)/media/view/media_view_group_thumbs.h
 <(src_loc)/media/view/media_view_overlay_widget.cpp
 <(src_loc)/media/view/media_view_overlay_widget.h
-<(src_loc)/mtproto/concurrent_sender.cpp
-<(src_loc)/mtproto/concurrent_sender.h
 <(src_loc)/mtproto/config_loader.cpp
 <(src_loc)/mtproto/config_loader.h
-<(src_loc)/mtproto/connection.cpp
-<(src_loc)/mtproto/connection.h
 <(src_loc)/mtproto/connection_abstract.cpp
 <(src_loc)/mtproto/connection_abstract.h
 <(src_loc)/mtproto/connection_http.cpp
@@ -552,8 +548,6 @@
 <(src_loc)/mtproto/connection_tcp.cpp
 <(src_loc)/mtproto/connection_tcp.h
 <(src_loc)/mtproto/core_types.h
-<(src_loc)/mtproto/dcenter.cpp
-<(src_loc)/mtproto/dcenter.h
 <(src_loc)/mtproto/dc_options.cpp
 <(src_loc)/mtproto/dc_options.h
 <(src_loc)/mtproto/dedicated_file_loader.cpp
@@ -565,6 +559,8 @@
 <(src_loc)/mtproto/sender.h
 <(src_loc)/mtproto/session.cpp
 <(src_loc)/mtproto/session.h
+<(src_loc)/mtproto/session_private.cpp
+<(src_loc)/mtproto/session_private.h
 <(src_loc)/mtproto/special_config_request.cpp
 <(src_loc)/mtproto/special_config_request.h
 <(src_loc)/mtproto/type_utils.h
diff --git a/Telegram/lib_tl b/Telegram/lib_tl
index 13918d5b5..10cddc61a 160000
--- a/Telegram/lib_tl
+++ b/Telegram/lib_tl
@@ -1 +1 @@
-Subproject commit 13918d5b5c4611ef1563a13ac1daf4d2c77c5f49
+Subproject commit 10cddc61a6c5b6cd896ba014fc187d15f5267be3

From 907965531c4ec64540e1e59a1cf9f4f58de0dc68 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 16:30:33 +0300
Subject: [PATCH 74/91] Don't bind key for more than 10 seconds.

---
 .../SourceFiles/mtproto/session_private.cpp   | 23 +++++++++++--------
 .../SourceFiles/mtproto/session_private.h     |  1 +
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/session_private.cpp b/Telegram/SourceFiles/mtproto/session_private.cpp
index ba718f8c2..6dc25c250 100644
--- a/Telegram/SourceFiles/mtproto/session_private.cpp
+++ b/Telegram/SourceFiles/mtproto/session_private.cpp
@@ -216,31 +216,30 @@ int16 SessionPrivate::getProtocolDcId() const {
 void SessionPrivate::checkSentRequests() {
 	clearOldContainers();
 
-	auto restarting = false;
+	const auto now = crl::now();
+	if (_bindMsgId && _bindMessageSent + kCheckSentRequestTimeout < now) {
+		DEBUG_LOG(("MTP Info: "
+			"Request state while key is not bound, restarting."));
+		restart();
+		return;
+	}
 	auto requesting = false;
 	{
 		QReadLocker locker(_sessionData->haveSentMutex());
 		auto &haveSent = _sessionData->haveSentMap();
 		const auto haveSentCount = haveSent.size();
-		const auto now = crl::now();
 		const auto checkAfter = kCheckSentRequestTimeout;
 		for (const auto &[msgId, request] : haveSent) {
 			if (request->lastSentTime + checkAfter < now) {
 				// Need to check state.
 				request->lastSentTime = now;
-				if (_bindMsgId) {
-					restarting = true;
-				} else if (_stateRequestData.emplace(msgId).second) {
+				if (_stateRequestData.emplace(msgId).second) {
 					requesting = true;
 				}
 			}
 		}
 	}
-	if (restarting) {
-		DEBUG_LOG(("MTP Info: "
-			"Request state while key is not bound, restarting."));
-		restart();
-	} else if (requesting) {
+	if (requesting) {
 		_sessionData->queueSendAnything(kSendStateRequestWaiting);
 	}
 }
@@ -683,6 +682,7 @@ void SessionPrivate::tryToSend() {
 				forceNewMsgId && !bindDcKeyRequest);
 			if (bindDcKeyRequest) {
 				_bindMsgId = msgId;
+				_bindMessageSent = crl::now();
 				needAnyResponse = true;
 			} else if (pingRequest) {
 				_pingMsgId = msgId;
@@ -779,6 +779,7 @@ void SessionPrivate::tryToSend() {
 					bigMsgId,
 					false,
 					bindDcKeyRequest);
+				_bindMessageSent = crl::now();
 				needAnyResponse = true;
 			}
 			if (pingRequest) {
@@ -1854,6 +1855,8 @@ SessionPrivate::HandleResult SessionPrivate::handleBindResponse(
 	if (!_keyCreator || !_bindMsgId || _bindMsgId != requestMsgId) {
 		return HandleResult::Ignored;
 	}
+	_bindMsgId = 0;
+
 	const auto result = _keyCreator->handleBindResponse(response);
 	switch (result) {
 	case DcKeyBindState::Success:
diff --git a/Telegram/SourceFiles/mtproto/session_private.h b/Telegram/SourceFiles/mtproto/session_private.h
index fcc32c704..c8632c8d2 100644
--- a/Telegram/SourceFiles/mtproto/session_private.h
+++ b/Telegram/SourceFiles/mtproto/session_private.h
@@ -221,6 +221,7 @@ private:
 
 	std::unique_ptr<BoundKeyCreator> _keyCreator;
 	mtpMsgId _bindMsgId = 0;
+	crl::time _bindMessageSent = 0;
 
 };
 

From de94afd96684ca1f688b86b92af075f9c46c23a6 Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Fri, 22 Nov 2019 13:16:43 +0300
Subject: [PATCH 75/91] Updated and fixed building-cmake.md.

---
 docs/building-cmake.md | 38 ++++++++++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/docs/building-cmake.md b/docs/building-cmake.md
index 8d046a62f..142ad5899 100644
--- a/docs/building-cmake.md
+++ b/docs/building-cmake.md
@@ -10,17 +10,26 @@ You will require **api_id** and **api_hash** to access the Telegram API servers.
 
 ### Install software and required packages
 
-You will need GCC 8.1 installed. To install them and all the required dependencies run
+You will need GCC 8 installed. To install them and all the required dependencies run
 
     sudo apt-get install software-properties-common -y && \
-    sudo apt-get install git libexif-dev liblzma-dev libz-dev libssl-dev libappindicator-dev libicu-dev libdee-dev libdrm-dev dh-autoreconf autoconf automake build-essential libass-dev libfreetype6-dev libgpac-dev libsdl1.2-dev libtheora-dev libtool libva-dev libvdpau-dev libvorbis-dev libxcb1-dev libxcb-image0-dev libxcb-shm0-dev libxcb-xfixes0-dev libxcb-keysyms1-dev libxcb-icccm4-dev libxcb-render-util0-dev libxcb-util0-dev libxcb-xkb-dev libxrender-dev libasound-dev libpulse-dev libxcb-sync0-dev libxcb-randr0-dev libx11-xcb-dev libffi-dev libncurses5-dev pkg-config texi2html zlib1g-dev yasm xutils-dev bison python-xcbgen chrpath gperf -y && \
+    sudo apt-get install git libexif-dev liblzma-dev libz-dev libssl-dev \
+    libappindicator-dev libicu-dev libdee-dev libdrm-dev dh-autoreconf \
+    autoconf automake build-essential libass-dev libfreetype6-dev \
+    libgpac-dev libsdl1.2-dev libtheora-dev libtool libva-dev libvdpau-dev \
+    libvorbis-dev libxcb1-dev libxcb-image0-dev libxcb-shm0-dev \
+    libxcb-xfixes0-dev libxcb-keysyms1-dev libxcb-icccm4-dev \
+    libxcb-render-util0-dev libxcb-util0-dev libxcb-xkb-dev libxrender-dev \
+    libasound-dev libpulse-dev libxcb-sync0-dev libxcb-randr0-dev bison \
+    libx11-xcb-dev libffi-dev libncurses5-dev pkg-config texi2html yasm \
+    zlib1g-dev xutils-dev python-xcbgen chrpath gperf -y --force-yes && \
     sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y && \
     sudo apt-get update && \
     sudo apt-get install gcc-8 g++-8 -y && \
     sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 60 && \
     sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-8 60 && \
     sudo update-alternatives --config gcc && \
-    sudo add-apt-repository --remove ppa:ubuntu-toolchain-r/test -y && \
+    sudo add-apt-repository --remove ppa:ubuntu-toolchain-r/test -y
 
 You can set the multithreaded make parameter by running
 
@@ -41,6 +50,7 @@ Go to ***BuildPath*** and run
     ./bootstrap
     make $MAKE_THREADS_CNT
     sudo make install
+    cd ..
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
@@ -237,7 +247,27 @@ Go to ***BuildPath*** and run
     git clone https://github.com/desktop-app/nimf.git
     cd ../../../..
 
-    ./configure -prefix "/usr/local/desktop-app/Qt-5.12.5" -release -force-debug-info -opensource -confirm-license -qt-zlib -qt-libpng -qt-libjpeg -qt-harfbuzz -qt-pcre -qt-xcb -system-freetype -fontconfig -no-opengl -no-gtk -static -openssl-linked -I "/usr/local/desktop-app/openssl-1.1.1/include" OPENSSL_LIBS="/usr/local/desktop-app/openssl-1.1.1/lib/libssl.a /usr/local/desktop-app/openssl-1.1.1/lib/libcrypto.a -ldl -lpthread" -nomake examples -nomake tests
+    OPENSSL_DIR=/usr/local/desktop-app/openssl-1.1.1
+    ./configure -prefix "/usr/local/desktop-app/Qt-5.12.5" \
+    -release \
+    -force-debug-info \
+    -opensource \
+    -confirm-license \
+    -qt-zlib \
+    -qt-libpng \
+    -qt-libjpeg \
+    -qt-harfbuzz \
+    -qt-pcre \
+    -qt-xcb \
+    -system-freetype \
+    -fontconfig \
+    -no-opengl \
+    -no-gtk \
+    -static \
+    -openssl-linked \
+    -I "$OPENSSL_DIR/include" OPENSSL_LIBS="$OPENSSL_DIR/lib/libssl.a $OPENSSL_DIR/lib/libcrypto.a -ldl -lpthread" \
+    -nomake examples \
+    -nomake tests
 
     make $MAKE_THREADS_CNT
     sudo make install

From d542291d8fc105bc0b7702e72d1e9b815973d15e Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Wed, 27 Nov 2019 00:07:03 +0300
Subject: [PATCH 76/91] Added ability to invoke macOS Character Palette.

---
 Telegram/Resources/langs/lang.strings                | 1 +
 Telegram/SourceFiles/platform/mac/main_window_mac.h  | 1 +
 Telegram/SourceFiles/platform/mac/main_window_mac.mm | 7 +++++++
 3 files changed, 9 insertions(+)

diff --git a/Telegram/Resources/langs/lang.strings b/Telegram/Resources/langs/lang.strings
index a6cb33086..30ea2a818 100644
--- a/Telegram/Resources/langs/lang.strings
+++ b/Telegram/Resources/langs/lang.strings
@@ -2238,6 +2238,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_mac_menu_new_group" = "New Group";
 "lng_mac_menu_new_channel" = "New Channel";
 "lng_mac_menu_show" = "Show Telegram";
+"lng_mac_menu_emoji_and_symbols" = "Emoji & Symbols";
 
 "lng_mac_touchbar_favorite_stickers" = "Favorite stickers";
 
diff --git a/Telegram/SourceFiles/platform/mac/main_window_mac.h b/Telegram/SourceFiles/platform/mac/main_window_mac.h
index 933c0e84c..f02027294 100644
--- a/Telegram/SourceFiles/platform/mac/main_window_mac.h
+++ b/Telegram/SourceFiles/platform/mac/main_window_mac.h
@@ -49,6 +49,7 @@ public slots:
 	void psMacPaste();
 	void psMacDelete();
 	void psMacSelectAll();
+	void psMacEmojiAndSymbols();
 
 	void psMacBold();
 	void psMacItalic();
diff --git a/Telegram/SourceFiles/platform/mac/main_window_mac.mm b/Telegram/SourceFiles/platform/mac/main_window_mac.mm
index 6bd5211d9..993b94630 100644
--- a/Telegram/SourceFiles/platform/mac/main_window_mac.mm
+++ b/Telegram/SourceFiles/platform/mac/main_window_mac.mm
@@ -716,6 +716,9 @@ void MainWindow::createGlobalMenu() {
 	edit->addSeparator();
 	psSelectAll = edit->addAction(tr::lng_mac_menu_select_all(tr::now), this, SLOT(psMacSelectAll()), QKeySequence::SelectAll);
 
+	edit->addSeparator();
+	edit->addAction(tr::lng_mac_menu_emoji_and_symbols(tr::now).replace('&', "&&"), this, SLOT(psMacEmojiAndSymbols()), QKeySequence(Qt::MetaModifier | Qt::ControlModifier | Qt::Key_Space));
+
 	QMenu *window = psMainMenu.addMenu(tr::lng_mac_menu_window(tr::now));
 	psContacts = window->addAction(tr::lng_mac_menu_contacts(tr::now));
 	connect(psContacts, &QAction::triggered, psContacts, crl::guard(this, [=] {
@@ -768,6 +771,10 @@ void MainWindow::psMacSelectAll() {
 	SendKeySequence(Qt::Key_A, Qt::ControlModifier);
 }
 
+void MainWindow::psMacEmojiAndSymbols() {
+	[NSApp orderFrontCharacterPalette:nil];
+}
+
 void MainWindow::psMacBold() {
 	SendKeySequence(Qt::Key_B, Qt::ControlModifier);
 }

From 872ff633b644aefa06c556e05d7de8697d0b7bc0 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 18:52:30 +0300
Subject: [PATCH 77/91] Update Qt patch.

---
 docs/building-cmake.md | 4 ++--
 docs/building-msvc.md  | 4 ++--
 docs/building-osx.md   | 4 ++--
 docs/building-xcode.md | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/docs/building-cmake.md b/docs/building-cmake.md
index 142ad5899..016bf7e85 100644
--- a/docs/building-cmake.md
+++ b/docs/building-cmake.md
@@ -18,7 +18,7 @@ You will need GCC 8 installed. To install them and all the required dependencies
     autoconf automake build-essential libass-dev libfreetype6-dev \
     libgpac-dev libsdl1.2-dev libtheora-dev libtool libva-dev libvdpau-dev \
     libvorbis-dev libxcb1-dev libxcb-image0-dev libxcb-shm0-dev \
-    libxcb-xfixes0-dev libxcb-keysyms1-dev libxcb-icccm4-dev \
+    libxcb-xfixes0-dev libxcb-keysyms1-dev libxcb-icccm4-dev libatspi2.0-dev \
     libxcb-render-util0-dev libxcb-util0-dev libxcb-xkb-dev libxrender-dev \
     libasound-dev libpulse-dev libxcb-sync0-dev libxcb-randr0-dev bison \
     libx11-xcb-dev libffi-dev libncurses5-dev pkg-config texi2html yasm \
@@ -54,7 +54,7 @@ Go to ***BuildPath*** and run
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ../
     git clone --branch 0.9.1 https://github.com/ericniebler/range-v3
 
diff --git a/docs/building-msvc.md b/docs/building-msvc.md
index baf337cf9..38df3e657 100644
--- a/docs/building-msvc.md
+++ b/docs/building-msvc.md
@@ -32,7 +32,7 @@ Open **x86 Native Tools Command Prompt for VS 2019.bat**, go to ***BuildPath***
     cd ThirdParty
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ../
     git clone https://chromium.googlesource.com/external/gyp
     cd gyp
@@ -64,7 +64,7 @@ Open **x86 Native Tools Command Prompt for VS 2019.bat**, go to ***BuildPath***
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ..
     git clone --branch 0.9.1 https://github.com/ericniebler/range-v3 range-v3
 
diff --git a/docs/building-osx.md b/docs/building-osx.md
index 8d51ed56b..a7facc4ce 100644
--- a/docs/building-osx.md
+++ b/docs/building-osx.md
@@ -33,7 +33,7 @@ Go to ***BuildPath*** and run
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ../
     git clone https://chromium.googlesource.com/external/gyp
     git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
@@ -50,7 +50,7 @@ Go to ***BuildPath*** and run
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ../
     git clone --branch 0.9.1 https://github.com/ericniebler/range-v3
 
diff --git a/docs/building-xcode.md b/docs/building-xcode.md
index a780a4ba0..c930dc214 100644
--- a/docs/building-xcode.md
+++ b/docs/building-xcode.md
@@ -33,7 +33,7 @@ Go to ***BuildPath*** and run
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ../
     git clone https://chromium.googlesource.com/external/gyp
     git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
@@ -50,7 +50,7 @@ Go to ***BuildPath*** and run
 
     git clone https://github.com/desktop-app/patches.git
     cd patches
-    git checkout 4aa377c
+    git checkout 395b620
     cd ../
     git clone --branch 0.9.1 https://github.com/ericniebler/range-v3
 

From 6f092bbb57d7a3ada861e0da102dd68c7ca51bf4 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 18:52:54 +0300
Subject: [PATCH 78/91] Closed alpha version 1.9.1.7.

---
 Telegram/Resources/uwp/AppX/AppxManifest.xml | 2 +-
 Telegram/Resources/winrc/Telegram.rc         | 8 ++++----
 Telegram/Resources/winrc/Updater.rc          | 8 ++++----
 Telegram/SourceFiles/core/version.h          | 2 +-
 Telegram/build/version                       | 2 +-
 5 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Telegram/Resources/uwp/AppX/AppxManifest.xml b/Telegram/Resources/uwp/AppX/AppxManifest.xml
index 268818013..a1902727c 100644
--- a/Telegram/Resources/uwp/AppX/AppxManifest.xml
+++ b/Telegram/Resources/uwp/AppX/AppxManifest.xml
@@ -9,7 +9,7 @@
   <Identity Name="TelegramMessengerLLP.TelegramDesktop"
     ProcessorArchitecture="ARCHITECTURE"
     Publisher="CN=536BC709-8EE1-4478-AF22-F0F0F26FF64A"
-    Version="1.9.1.6" />
+    Version="1.9.1.7" />
   <Properties>
     <DisplayName>Telegram Desktop</DisplayName>
     <PublisherDisplayName>Telegram FZ-LLC</PublisherDisplayName>
diff --git a/Telegram/Resources/winrc/Telegram.rc b/Telegram/Resources/winrc/Telegram.rc
index 2e9d22a42..e1f30a98f 100644
--- a/Telegram/Resources/winrc/Telegram.rc
+++ b/Telegram/Resources/winrc/Telegram.rc
@@ -33,8 +33,8 @@ IDI_ICON1               ICON                    "..\\art\\icon256.ico"
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,6
- PRODUCTVERSION 1,9,1,6
+ FILEVERSION 1,9,1,7
+ PRODUCTVERSION 1,9,1,7
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -51,10 +51,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop"
-            VALUE "FileVersion", "1.9.1.6"
+            VALUE "FileVersion", "1.9.1.7"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.6"
+            VALUE "ProductVersion", "1.9.1.7"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/Resources/winrc/Updater.rc b/Telegram/Resources/winrc/Updater.rc
index eaf84e301..0c3c252af 100644
--- a/Telegram/Resources/winrc/Updater.rc
+++ b/Telegram/Resources/winrc/Updater.rc
@@ -24,8 +24,8 @@ LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 1,9,1,6
- PRODUCTVERSION 1,9,1,6
+ FILEVERSION 1,9,1,7
+ PRODUCTVERSION 1,9,1,7
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -42,10 +42,10 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Telegram FZ-LLC"
             VALUE "FileDescription", "Telegram Desktop Updater"
-            VALUE "FileVersion", "1.9.1.6"
+            VALUE "FileVersion", "1.9.1.7"
             VALUE "LegalCopyright", "Copyright (C) 2014-2019"
             VALUE "ProductName", "Telegram Desktop"
-            VALUE "ProductVersion", "1.9.1.6"
+            VALUE "ProductVersion", "1.9.1.7"
         END
     END
     BLOCK "VarFileInfo"
diff --git a/Telegram/SourceFiles/core/version.h b/Telegram/SourceFiles/core/version.h
index fadf33d70..a75a56ab2 100644
--- a/Telegram/SourceFiles/core/version.h
+++ b/Telegram/SourceFiles/core/version.h
@@ -7,7 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #pragma once
 
-#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001006ULL)
+#define TDESKTOP_REQUESTED_ALPHA_VERSION (1009001007ULL)
 
 #ifdef TDESKTOP_OFFICIAL_TARGET
 #define TDESKTOP_ALPHA_VERSION TDESKTOP_REQUESTED_ALPHA_VERSION
diff --git a/Telegram/build/version b/Telegram/build/version
index a3fb38894..4487b9a99 100644
--- a/Telegram/build/version
+++ b/Telegram/build/version
@@ -3,4 +3,4 @@ AppVersionStrMajor 1.9
 AppVersionStrSmall 1.9.1
 AppVersionStr      1.9.1
 BetaChannel        0
-AlphaVersion       1009001006
+AlphaVersion       1009001007

From 66961dce8325157306db5f4974892728f7e676ad Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 19:23:59 +0300
Subject: [PATCH 79/91] Closed alpha version 1.9.1.7: Update lib_spellcheck.

---
 Telegram/lib_spellcheck | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/lib_spellcheck b/Telegram/lib_spellcheck
index 47b2f293c..3f5a78d9b 160000
--- a/Telegram/lib_spellcheck
+++ b/Telegram/lib_spellcheck
@@ -1 +1 @@
-Subproject commit 47b2f293c3b63ccbe871ab6d50edd8d4b8411ecc
+Subproject commit 3f5a78d9b10a82f3335d90f59192ecc999d7e605

From 524d64a46214956cadf7eaf08d854c2747d30de9 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 29 Nov 2019 16:42:42 +0300
Subject: [PATCH 80/91] Clip intro animation by Next button.

---
 Telegram/SourceFiles/intro/intro_step.cpp   | 7 +++++++
 Telegram/SourceFiles/intro/intro_step.h     | 3 +++
 Telegram/SourceFiles/intro/intro_widget.cpp | 3 +++
 3 files changed, 13 insertions(+)

diff --git a/Telegram/SourceFiles/intro/intro_step.cpp b/Telegram/SourceFiles/intro/intro_step.cpp
index 151951b49..681a5020a 100644
--- a/Telegram/SourceFiles/intro/intro_step.cpp
+++ b/Telegram/SourceFiles/intro/intro_step.cpp
@@ -233,6 +233,9 @@ bool Step::paintAnimated(Painter &p, QRect clip) {
 		}
 		return false;
 	}
+	if (!_coverAnimation.clipping.isEmpty()) {
+		p.setClipRect(_coverAnimation.clipping);
+	}
 
 	auto progress = (hasCover() ? anim::easeOutCirc(1., dt) : anim::linear(1., dt));
 	auto arrivingAlpha = progress;
@@ -451,6 +454,10 @@ void Step::showAnimated(Direction direction) {
 	}
 }
 
+void Step::setShowAnimationClipping(QRect clipping) {
+	_coverAnimation.clipping = clipping;
+}
+
 void Step::setGoCallback(Fn<void(Step *step, Direction direction)> callback) {
 	_goCallback = std::move(callback);
 }
diff --git a/Telegram/SourceFiles/intro/intro_step.h b/Telegram/SourceFiles/intro/intro_step.h
index c53826622..c51db5e42 100644
--- a/Telegram/SourceFiles/intro/intro_step.h
+++ b/Telegram/SourceFiles/intro/intro_step.h
@@ -64,6 +64,7 @@ public:
 	void showAnimated(Direction direction);
 	void showFast();
 	[[nodiscard]] bool animating() const;
+	void setShowAnimationClipping(QRect clipping);
 
 	[[nodiscard]] bool hasCover() const;
 	[[nodiscard]] virtual bool hasBack() const;
@@ -142,6 +143,8 @@ private:
 		// From content top till the next button top.
 		QPixmap contentSnapshotWas;
 		QPixmap contentSnapshotNow;
+
+		QRect clipping;
 	};
 	void updateLabelsPosition();
 	void paintContentSnapshot(
diff --git a/Telegram/SourceFiles/intro/intro_widget.cpp b/Telegram/SourceFiles/intro/intro_widget.cpp
index 078c43f3e..6b2bd5c32 100644
--- a/Telegram/SourceFiles/intro/intro_widget.cpp
+++ b/Telegram/SourceFiles/intro/intro_widget.cpp
@@ -639,6 +639,9 @@ void Widget::updateControlsGeometry() {
 		nextTop,
 		shownAmount);
 	_next->moveToLeft((width() - _next->width()) / 2, realNextTop);
+	getStep()->setShowAnimationClipping(shownAmount > 0
+		? QRect(0, 0, width(), realNextTop)
+		: QRect());
 	if (_changeLanguage) {
 		_changeLanguage->moveToLeft((width() - _changeLanguage->width()) / 2, _next->y() + _next->height() + _changeLanguage->height());
 	}

From 12f5ccaaa5ac4a1442c827ae1a1fbfa3f7b543b8 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 Dec 2019 10:28:33 +0300
Subject: [PATCH 81/91] Use vector queues in mtproto file downloader.

---
 Telegram/SourceFiles/boxes/peer_list_box.cpp  |   1 -
 Telegram/SourceFiles/boxes/share_box.cpp      |   1 -
 .../dialogs/dialogs_inner_widget.cpp          |   1 -
 .../SourceFiles/history/history_widget.cpp    |   2 -
 .../media/view/media_view_overlay_widget.cpp  |   1 -
 .../SourceFiles/storage/file_download.cpp     | 382 +++++++++---------
 Telegram/SourceFiles/storage/file_download.h  | 105 ++---
 .../storage/streamed_file_downloader.cpp      |  26 +-
 .../storage/streamed_file_downloader.h        |   5 +-
 9 files changed, 252 insertions(+), 272 deletions(-)

diff --git a/Telegram/SourceFiles/boxes/peer_list_box.cpp b/Telegram/SourceFiles/boxes/peer_list_box.cpp
index 3259bc737..821c7641f 100644
--- a/Telegram/SourceFiles/boxes/peer_list_box.cpp
+++ b/Telegram/SourceFiles/boxes/peer_list_box.cpp
@@ -1287,7 +1287,6 @@ void PeerListContent::loadProfilePhotos() {
 
 	auto yFrom = _visibleTop;
 	auto yTo = _visibleBottom + (_visibleBottom - _visibleTop) * PreloadHeightsCount;
-	_controller->session().downloader().clearPriorities();
 
 	if (yTo < 0) return;
 	if (yFrom < 0) yFrom = 0;
diff --git a/Telegram/SourceFiles/boxes/share_box.cpp b/Telegram/SourceFiles/boxes/share_box.cpp
index 0f319b401..49c2b32ee 100644
--- a/Telegram/SourceFiles/boxes/share_box.cpp
+++ b/Telegram/SourceFiles/boxes/share_box.cpp
@@ -722,7 +722,6 @@ void ShareBox::Inner::loadProfilePhotos(int yFrom) {
 	yFrom *= _columnCount;
 	yTo *= _columnCount;
 
-	_navigation->session().downloader().clearPriorities();
 	if (_filter.isEmpty()) {
 		if (!_chatsIndexed->empty()) {
 			auto i = _chatsIndexed->cfind(yFrom, _rowHeight);
diff --git a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
index a0de1069c..a1d81b96e 100644
--- a/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
+++ b/Telegram/SourceFiles/dialogs/dialogs_inner_widget.cpp
@@ -2464,7 +2464,6 @@ void InnerWidget::loadPeerPhotos() {
 
 	auto yFrom = _visibleTop;
 	auto yTo = _visibleTop + (_visibleBottom - _visibleTop) * (PreloadHeightsCount + 1);
-	session().downloader().clearPriorities();
 	if (_state == WidgetState::Default) {
 		auto otherStart = shownDialogs()->size() * st::dialogsRowHeight;
 		if (yFrom < otherStart) {
diff --git a/Telegram/SourceFiles/history/history_widget.cpp b/Telegram/SourceFiles/history/history_widget.cpp
index 3ff0e1619..cb61ad11f 100644
--- a/Telegram/SourceFiles/history/history_widget.cpp
+++ b/Telegram/SourceFiles/history/history_widget.cpp
@@ -1798,8 +1798,6 @@ void HistoryWidget::showHistory(
 	_nonEmptySelection = false;
 
 	if (_peer) {
-		session().downloader().clearPriorities();
-
 		_history = _peer->owner().history(_peer);
 		_migrated = _history->migrateFrom();
 		if (_migrated
diff --git a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
index aca34d996..56f93e9b4 100644
--- a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
+++ b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
@@ -1803,7 +1803,6 @@ void OverlayWidget::displayPhoto(not_null<PhotoData*> photo, HistoryItem *item)
 
 	_zoom = 0;
 	_zoomToScreen = 0;
-	Auth().downloader().clearPriorities();
 	_blurred = true;
 	_current = QPixmap();
 	_down = OverNone;
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index e56544935..0f2d647eb 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -32,6 +32,8 @@ constexpr auto kKillSessionTimeout = 15 * crl::time(1000);
 // Max 16 file parts downloaded at the same time, 128 KB each.
 constexpr auto kMaxFileQueries = 16;
 
+constexpr auto kMaxWaitedInConnection = 512 * 1024;
+
 // Max 8 http[s] files downloaded at the same time.
 constexpr auto kMaxWebFileQueries = 8;
 
@@ -43,17 +45,108 @@ constexpr auto kPartSize = 128 * 1024;
 
 } // namespace
 
+void Downloader::Queue::enqueue(not_null<FileLoader*> loader) {
+	const auto i = ranges::find(_loaders, loader);
+	if (i != end(_loaders)) {
+		return;
+	}
+	_loaders.push_back(loader);
+	_previousGeneration.erase(
+		ranges::remove(_previousGeneration, loader),
+		end(_previousGeneration));
+}
+
+void Downloader::Queue::remove(not_null<FileLoader*> loader) {
+	_loaders.erase(ranges::remove(_loaders, loader), end(_loaders));
+	_previousGeneration.erase(
+		ranges::remove(_previousGeneration, loader),
+		end(_previousGeneration));
+}
+
+void Downloader::Queue::resetGeneration() {
+	if (!_previousGeneration.empty()) {
+		_loaders.reserve(_loaders.size() + _previousGeneration.size());
+		std::copy(
+			begin(_previousGeneration),
+			end(_previousGeneration),
+			std::back_inserter(_loaders));
+		_previousGeneration.clear();
+	}
+	std::swap(_loaders, _previousGeneration);
+}
+
+FileLoader *Downloader::Queue::nextLoader() const {
+	auto &&all = ranges::view::concat(_loaders, _previousGeneration);
+	const auto i = ranges::find(all, true, &FileLoader::readyToRequest);
+	return (i != all.end()) ? i->get() : nullptr;
+}
+
 Downloader::Downloader(not_null<ApiWrap*> api)
 : _api(api)
-, _killDownloadSessionsTimer([=] { killDownloadSessions(); })
-, _queueForWeb(kMaxWebFileQueries) {
+, _killDownloadSessionsTimer([=] { killDownloadSessions(); }) {
 }
 
-void Downloader::clearPriorities() {
-	++_priority;
+Downloader::~Downloader() {
+	killDownloadSessions();
 }
 
-void Downloader::requestedAmountIncrement(MTP::DcId dcId, int index, int amount) {
+void Downloader::enqueue(not_null<FileLoader*> loader) {
+	const auto dcId = loader->dcId();
+	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).enqueue(loader);
+	if (!_resettingGeneration) {
+		_resettingGeneration = true;
+		crl::on_main(this, [=] {
+			resetGeneration();
+		});
+	}
+	checkSendNext();
+}
+
+void Downloader::remove(not_null<FileLoader*> loader) {
+	const auto dcId = loader->dcId();
+	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).remove(loader);
+	crl::on_main(&_api->session(), [=] { checkSendNext(); });
+}
+
+void Downloader::resetGeneration() {
+	_resettingGeneration = false;
+	for (auto &[dcId, queue] : _mtprotoLoaders) {
+		queue.resetGeneration();
+	}
+	_webLoaders.resetGeneration();
+}
+
+void Downloader::checkSendNext() {
+	for (auto &[dcId, queue] : _mtprotoLoaders) {
+		const auto bestIndex = [&] {
+			const auto i = _requestedBytesAmount.find(dcId);
+			if (i == end(_requestedBytesAmount)) {
+				return 0;
+			}
+			const auto j = ranges::min_element(i->second);
+			const auto inConnection = *j;
+			return (inConnection + kPartSize <= kMaxWaitedInConnection)
+				? (j - begin(i->second))
+				: -1;
+		}();
+		if (bestIndex < 0) {
+			continue;
+		}
+		if (const auto loader = queue.nextLoader()) {
+			loader->loadPart(bestIndex);
+		}
+	}
+	if (_requestedBytesAmount[0][0] < kMaxWebFileQueries) {
+		if (const auto loader = _webLoaders.nextLoader()) {
+			loader->loadPart(0);
+		}
+	}
+}
+
+void Downloader::requestedAmountIncrement(
+		MTP::DcId dcId,
+		int index,
+		int amount) {
 	Expects(index >= 0 && index < MTP::kDownloadSessionsCount);
 
 	using namespace rpl::mappers;
@@ -63,6 +156,9 @@ void Downloader::requestedAmountIncrement(MTP::DcId dcId, int index, int amount)
 		it = _requestedBytesAmount.emplace(dcId, RequestedInDc { { 0 } }).first;
 	}
 	it->second[index] += amount;
+	if (!dcId) {
+		return; // webLoaders.
+	}
 	if (amount > 0) {
 		killDownloadSessionsStop(dcId);
 	} else if (ranges::find_if(it->second, _1 > 0) == end(it->second)) {
@@ -70,6 +166,13 @@ void Downloader::requestedAmountIncrement(MTP::DcId dcId, int index, int amount)
 	}
 }
 
+int Downloader::chooseDcIndexForRequest(MTP::DcId dcId) {
+	const auto i = _requestedBytesAmount.find(dcId);
+	return (i != end(_requestedBytesAmount))
+		? (ranges::min_element(i->second) - begin(i->second))
+		: 0;
+}
+
 void Downloader::killDownloadSessionsStart(MTP::DcId dcId) {
 	if (!_killDownloadSessionTimes.contains(dcId)) {
 		_killDownloadSessionTimes.emplace(
@@ -110,35 +213,6 @@ void Downloader::killDownloadSessions() {
 	}
 }
 
-int Downloader::chooseDcIndexForRequest(MTP::DcId dcId) const {
-	auto result = 0;
-	auto it = _requestedBytesAmount.find(dcId);
-	if (it != _requestedBytesAmount.cend()) {
-		for (auto i = 1; i != MTP::kDownloadSessionsCount; ++i) {
-			if (it->second[i] < it->second[result]) {
-				result = i;
-			}
-		}
-	}
-	return result;
-}
-
-not_null<Downloader::Queue*> Downloader::queueForDc(MTP::DcId dcId) {
-	const auto i = _queuesForDc.find(dcId);
-	const auto result = (i != end(_queuesForDc))
-		? i
-		: _queuesForDc.emplace(dcId, Queue(kMaxFileQueries)).first;
-	return &result->second;
-}
-
-not_null<Downloader::Queue*> Downloader::queueForWeb() {
-	return &_queueForWeb;
-}
-
-Downloader::~Downloader() {
-	killDownloadSessions();
-}
-
 } // namespace Storage
 
 namespace {
@@ -154,13 +228,15 @@ WebLoadMainManager *_webLoadMainManager = nullptr;
 
 FileLoader::FileLoader(
 	const QString &toFile,
+	MTP::DcId dcId,
 	int32 size,
 	LocationType locationType,
 	LoadToCacheSetting toCache,
 	LoadFromCloudSetting fromCloud,
 	bool autoLoading,
 	uint8 cacheTag)
-: _downloader(&Auth().downloader())
+: _dcId(dcId)
+, _downloader(&Auth().downloader())
 , _autoLoading(autoLoading)
 , _cacheTag(cacheTag)
 , _filename(toFile)
@@ -172,6 +248,10 @@ FileLoader::FileLoader(
 	Expects(!_filename.isEmpty() || (_size <= Storage::kMaxFileInMemory));
 }
 
+FileLoader::~FileLoader() {
+	_downloader->remove(this);
+}
+
 Main::Session &FileLoader::session() const {
 	return _downloader->api().session();
 }
@@ -257,46 +337,7 @@ void FileLoader::permitLoadFromCloud() {
 }
 
 void FileLoader::notifyAboutProgress() {
-	const auto queue = _queue;
 	emit progress(this);
-	LoadNextFromQueue(queue);
-}
-
-void FileLoader::LoadNextFromQueue(not_null<Queue*> queue) {
-	if (queue->queriesCount >= queue->queriesLimit) {
-		return;
-	}
-	for (auto i = queue->start; i;) {
-		if (i->loadPart()) {
-			if (queue->queriesCount >= queue->queriesLimit) {
-				return;
-			}
-		} else {
-			i = i->_next;
-		}
-	}
-}
-
-void FileLoader::removeFromQueue() {
-	if (!_inQueue) return;
-	if (_next) {
-		_next->_prev = _prev;
-	}
-	if (_prev) {
-		_prev->_next = _next;
-	}
-	if (_queue->end == this) {
-		_queue->end = _prev;
-	}
-	if (_queue->start == this) {
-		_queue->start = _next;
-	}
-	_next = _prev = nullptr;
-	_inQueue = false;
-}
-
-FileLoader::~FileLoader() {
-	removeFromQueue();
 }
 
 void FileLoader::localLoaded(
@@ -331,71 +372,7 @@ void FileLoader::start() {
 			return cancel(true);
 		}
 	}
-
-	auto currentPriority = _downloader->currentPriority();
-	FileLoader *before = nullptr, *after = nullptr;
-	if (_inQueue && _priority == currentPriority) {
-		if (!_next || _next->_priority < currentPriority) return startLoading();
-		after = _next;
-		while (after->_next && after->_next->_priority == currentPriority) {
-			after = after->_next;
-		}
-	} else {
-		_priority = currentPriority;
-		if (_inQueue) {
-			if (_next && _next->_priority == currentPriority) {
-				after = _next;
-			} else if (_prev && _prev->_priority < currentPriority) {
-				before = _prev;
-				while (before->_prev && before->_prev->_priority < currentPriority) {
-					before = before->_prev;
-				}
-			} else {
-				return startLoading();
-			}
-		} else {
-			if (_queue->start && _queue->start->_priority == currentPriority) {
-				after = _queue->start;
-			} else {
-				before = _queue->start;
-			}
-		}
-		if (after) {
-			while (after->_next && after->_next->_priority == currentPriority) {
-				after = after->_next;
-			}
-		}
-	}
-
-	removeFromQueue();
-
-	_inQueue = true;
-	if (!_queue->start) {
-		_queue->start = _queue->end = this;
-	} else if (before) {
-		if (before != _next) {
-			_prev = before->_prev;
-			_next = before;
-			_next->_prev = this;
-			if (_prev) {
-				_prev->_next = this;
-			}
-			if (_queue->start->_prev) _queue->start = _queue->start->_prev;
-		}
-	} else if (after) {
-		if (after != _prev) {
-			_next = after->_next;
-			_prev = after;
-			after->_next = this;
-			if (_next) {
-				_next->_prev = this;
-			}
-			if (_queue->end->_next) _queue->end = _queue->end->_next;
-		}
-	} else {
-		LOG(("Queue Error: _start && !before && !after"));
-	}
-	return startLoading();
+	_downloader->enqueue(this);
 }
 
 void FileLoader::loadLocal(const Storage::Cache::Key &key) {
@@ -480,9 +457,8 @@ void FileLoader::cancel(bool fail) {
 		_file.remove();
 	}
 	_data = QByteArray();
-	removeFromQueue();
 
-	const auto queue = _queue;
+	const auto downloader = _downloader;
 	const auto sessionGuard = &session();
 	const auto weak = QPointer<FileLoader>(this);
 	if (fail) {
@@ -494,16 +470,6 @@ void FileLoader::cancel(bool fail) {
 		_filename = QString();
 		_file.setFileName(_filename);
 	}
-
-	// Current cancel() call could be made from ~Main::Session().
-	crl::on_main(sessionGuard, [=] { LoadNextFromQueue(queue); });
-}
-
-void FileLoader::startLoading() {
-	if ((_queue->queriesCount >= _queue->queriesLimit) || _finished) {
-		return;
-	}
-	loadPart();
 }
 
 int FileLoader::currentOffset() const {
@@ -594,7 +560,7 @@ bool FileLoader::finalizeResult() {
 		Platform::File::PostprocessDownloaded(
 			QFileInfo(_file).absoluteFilePath());
 	}
-	removeFromQueue();
+	_downloader->remove(this);
 
 	if (_localStatus == LocalStatus::NotFound) {
 		if (const auto key = fileLocationKey()) {
@@ -627,6 +593,7 @@ mtpFileLoader::mtpFileLoader(
 	uint8 cacheTag)
 : FileLoader(
 	to,
+	location.dcId(),
 	size,
 	type,
 	toCache,
@@ -635,7 +602,6 @@ mtpFileLoader::mtpFileLoader(
 	cacheTag)
 , _location(location)
 , _origin(origin) {
-	_queue = _downloader->queueForDc(dcId());
 }
 
 mtpFileLoader::mtpFileLoader(
@@ -646,6 +612,7 @@ mtpFileLoader::mtpFileLoader(
 	uint8 cacheTag)
 : FileLoader(
 	QString(),
+	Global::WebFileDcId(),
 	size,
 	UnknownFileLocation,
 	LoadToCacheAsWell,
@@ -653,7 +620,6 @@ mtpFileLoader::mtpFileLoader(
 	autoLoading,
 	cacheTag)
 , _location(location) {
-	_queue = _downloader->queueForDc(dcId());
 }
 
 mtpFileLoader::mtpFileLoader(
@@ -664,6 +630,7 @@ mtpFileLoader::mtpFileLoader(
 	uint8 cacheTag)
 : FileLoader(
 	QString(),
+	Global::WebFileDcId(),
 	size,
 	UnknownFileLocation,
 	LoadToCacheAsWell,
@@ -671,7 +638,10 @@ mtpFileLoader::mtpFileLoader(
 	autoLoading,
 	cacheTag)
 , _location(location) {
-	_queue = _downloader->queueForDc(dcId());
+}
+
+mtpFileLoader::~mtpFileLoader() {
+	cancelRequests();
 }
 
 Data::FileOrigin mtpFileLoader::fileOrigin() const {
@@ -703,31 +673,26 @@ void mtpFileLoader::refreshFileReferenceFrom(
 	makeRequest(offset);
 }
 
-bool mtpFileLoader::loadPart() {
-	if (_finished || _lastComplete || (!_sentRequests.empty() && !_size)) {
-		return false;
-	} else if (_size && _nextRequestOffset >= _size) {
-		return false;
-	}
+bool mtpFileLoader::readyToRequest() const {
+	return !_finished
+		&& !_lastComplete
+		&& (_sentRequests.empty() || _size != 0)
+		&& (!_size || _nextRequestOffset < _size);
+}
 
-	makeRequest(_nextRequestOffset);
+void mtpFileLoader::loadPart(int dcIndex) {
+	Expects(readyToRequest());
+
+	makeRequest(_nextRequestOffset, dcIndex);
 	_nextRequestOffset += Storage::kPartSize;
-	return true;
 }
 
-MTP::DcId mtpFileLoader::dcId() const {
-	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
-		return storage->dcId();
-	}
-	return Global::WebFileDcId();
-}
-
-mtpFileLoader::RequestData mtpFileLoader::prepareRequest(int offset) const {
+mtpFileLoader::RequestData mtpFileLoader::prepareRequest(
+		int offset,
+		int dcIndex) const {
 	auto result = RequestData();
 	result.dcId = _cdnDcId ? _cdnDcId : dcId();
-	result.dcIndex = _size
-		? _downloader->chooseDcIndexForRequest(result.dcId)
-		: 0;
+	result.dcIndex = dcIndex;
 	result.offset = offset;
 	return result;
 }
@@ -796,13 +761,17 @@ mtpRequestId mtpFileLoader::sendRequest(const RequestData &requestData) {
 	});
 }
 
-void mtpFileLoader::makeRequest(int offset) {
+void mtpFileLoader::makeRequest(int offset, int dcIndex) {
 	Expects(!_finished);
 
-	auto requestData = prepareRequest(offset);
+	auto requestData = prepareRequest(offset, dcIndex);
 	placeSentRequest(sendRequest(requestData), requestData);
 }
 
+void mtpFileLoader::makeRequest(int offset) {
+	makeRequest(offset, _downloader->chooseDcIndexForRequest(dcId()));
+}
+
 void mtpFileLoader::requestMoreCdnFileHashes() {
 	Expects(!_finished);
 
@@ -1011,7 +980,6 @@ void mtpFileLoader::placeSentRequest(
 		requestData.dcId,
 		requestData.dcIndex,
 		Storage::kPartSize);
-	++_queue->queriesCount;
 	_sentRequests.emplace(requestId, requestData);
 }
 
@@ -1024,8 +992,6 @@ int mtpFileLoader::finishSentRequestGetOffset(mtpRequestId requestId) {
 		requestData.dcId,
 		requestData.dcIndex,
 		-Storage::kPartSize);
-
-	--_queue->queriesCount;
 	_sentRequests.erase(it);
 
 	return requestData.offset;
@@ -1196,10 +1162,6 @@ std::optional<MediaKey> mtpFileLoader::fileLocationKey() const {
 	return std::nullopt;
 }
 
-mtpFileLoader::~mtpFileLoader() {
-	cancelRequests();
-}
-
 webFileLoader::webFileLoader(
 	const QString &url,
 	const QString &to,
@@ -1209,21 +1171,28 @@ webFileLoader::webFileLoader(
 : FileLoader(
 	QString(),
 	0,
+	0,
 	UnknownFileLocation,
 	LoadToCacheAsWell,
 	fromCloud,
 	autoLoading,
 	cacheTag)
 , _url(url) {
-	_queue = _downloader->queueForWeb();
 }
 
-bool webFileLoader::loadPart() {
-	if (_finished
-		|| _requestSent
-		|| _webLoadManager == FinishedWebLoadManager) {
-		return false;
-	}
+webFileLoader::~webFileLoader() {
+	markAsNotSent();
+}
+
+bool webFileLoader::readyToRequest() const {
+	return !_finished
+		&& !_requestSent
+		&& (_webLoadManager != FinishedWebLoadManager);
+}
+
+void webFileLoader::loadPart(int dcIndex) {
+	Expects(readyToRequest());
+
 	if (!_webLoadManager) {
 		_webLoadMainManager = new WebLoadMainManager();
 
@@ -1233,9 +1202,8 @@ bool webFileLoader::loadPart() {
 		_webLoadThread->start();
 	}
 
-	_requestSent = true;
+	markAsSent();
 	_webLoadManager->append(this, _url);
-	return false;
 }
 
 int webFileLoader::currentOffset() const {
@@ -1249,6 +1217,7 @@ void webFileLoader::loadProgress(qint64 already, qint64 size) {
 }
 
 void webFileLoader::loadFinished(const QByteArray &data) {
+	markAsNotSent();
 	if (writeResultPart(0, bytes::make_span(data))) {
 		if (finalizeResult()) {
 			notifyAboutProgress();
@@ -1257,6 +1226,7 @@ void webFileLoader::loadFinished(const QByteArray &data) {
 }
 
 void webFileLoader::loadError() {
+	markAsNotSent();
 	cancel(true);
 }
 
@@ -1269,11 +1239,27 @@ std::optional<MediaKey> webFileLoader::fileLocationKey() const {
 }
 
 void webFileLoader::cancelRequests() {
-	if (!webLoadManager()) return;
+	if (!webLoadManager()) {
+		return;
+	}
 	webLoadManager()->stop(this);
+	markAsNotSent();
 }
 
-webFileLoader::~webFileLoader() {
+void webFileLoader::markAsSent() {
+	if (_requestSent) {
+		return;
+	}
+	_requestSent = true;
+	_downloader->requestedAmountIncrement(0, 0, 1);
+}
+
+void webFileLoader::markAsNotSent() {
+	if (!_requestSent) {
+		return;
+	}
+	_requestSent = false;
+	_downloader->requestedAmountIncrement(0, 0, -1);
 }
 
 class webFileLoaderPrivate {
@@ -1372,6 +1358,10 @@ WebLoadManager::WebLoadManager(QThread *thread) {
 #endif // OS_MAC_OLD
 }
 
+WebLoadManager::~WebLoadManager() {
+	clear();
+}
+
 void WebLoadManager::append(webFileLoader *loader, const QString &url) {
 	loader->_private = new webFileLoaderPrivate(loader, url);
 
@@ -1606,10 +1596,6 @@ void WebLoadManager::clear() {
 	_replies.clear();
 }
 
-WebLoadManager::~WebLoadManager() {
-	clear();
-}
-
 void WebLoadMainManager::progress(webFileLoader *loader, qint64 already, qint64 size) {
 	if (webLoadManager() && webLoadManager()->carries(loader)) {
 		loader->loadProgress(already, size);
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index 32f20677b..cd098555e 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -16,6 +16,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtNetwork/QNetworkReply>
 
 class ApiWrap;
+class FileLoader;
 
 namespace Main {
 class Session;
@@ -35,48 +36,51 @@ constexpr auto kMaxWallPaperInMemory = kMaxFileInMemory;
 constexpr auto kMaxAnimationInMemory = kMaxFileInMemory; // 10 MB gif and mp4 animations held in memory while playing
 constexpr auto kMaxWallPaperDimension = 4096; // 4096x4096 is max area.
 
-class Downloader final {
+class Downloader final : public base::has_weak_ptr {
 public:
-	struct Queue {
-		Queue(int queriesLimit) : queriesLimit(queriesLimit) {
-		}
-		int queriesCount = 0;
-		int queriesLimit = 0;
-		FileLoader *start = nullptr;
-		FileLoader *end = nullptr;
-	};
-
 	explicit Downloader(not_null<ApiWrap*> api);
 	~Downloader();
 
-	ApiWrap &api() const {
+	[[nodiscard]] ApiWrap &api() const {
 		return *_api;
 	}
 
-	int currentPriority() const {
-		return _priority;
-	}
-	void clearPriorities();
+	void enqueue(not_null<FileLoader*> loader);
+	void remove(not_null<FileLoader*> loader);
 
-	base::Observable<void> &taskFinished() {
+	[[nodiscard]] base::Observable<void> &taskFinished() {
 		return _taskFinishedObservable;
 	}
 
+	// dcId == 0 is for web requests.
 	void requestedAmountIncrement(MTP::DcId dcId, int index, int amount);
-	int chooseDcIndexForRequest(MTP::DcId dcId) const;
-
-	not_null<Queue*> queueForDc(MTP::DcId dcId);
-	not_null<Queue*> queueForWeb();
+	[[nodiscard]] int chooseDcIndexForRequest(MTP::DcId dcId);
 
 private:
+	class Queue final {
+	public:
+		void enqueue(not_null<FileLoader*> loader);
+		void remove(not_null<FileLoader*> loader);
+		void resetGeneration();
+		[[nodiscard]] FileLoader *nextLoader() const;
+
+	private:
+		std::vector<not_null<FileLoader*>> _loaders;
+		std::vector<not_null<FileLoader*>> _previousGeneration;
+
+	};
+
+	void checkSendNext();
+
 	void killDownloadSessionsStart(MTP::DcId dcId);
 	void killDownloadSessionsStop(MTP::DcId dcId);
 	void killDownloadSessions();
 
-	not_null<ApiWrap*> _api;
+	void resetGeneration();
+
+	const not_null<ApiWrap*> _api;
 
 	base::Observable<void> _taskFinishedObservable;
-	int _priority = 1;
 
 	using RequestedInDc = std::array<int64, MTP::kDownloadSessionsCount>;
 	base::flat_map<MTP::DcId, RequestedInDc> _requestedBytesAmount;
@@ -84,8 +88,9 @@ private:
 	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
 	base::Timer _killDownloadSessionsTimer;
 
-	std::map<MTP::DcId, Queue> _queuesForDc;
-	Queue _queueForWeb;
+	base::flat_map<MTP::DcId, Queue> _mtprotoLoaders;
+	Queue _webLoaders;
+	bool _resettingGeneration = false;
 
 };
 
@@ -100,15 +105,13 @@ struct StorageImageSaved {
 
 };
 
-class mtpFileLoader;
-class webFileLoader;
-
 class FileLoader : public QObject {
 	Q_OBJECT
 
 public:
 	FileLoader(
 		const QString &toFile,
+		MTP::DcId dcId,
 		int32 size,
 		LocationType locationType,
 		LoadToCacheSetting toCache,
@@ -147,12 +150,6 @@ public:
 	void start();
 	void cancel();
 
-	bool loading() const {
-		return _inQueue;
-	}
-	bool started() const {
-		return _inQueue;
-	}
 	bool loadingLocal() const {
 		return (_localStatus == LocalStatus::Loading);
 	}
@@ -174,7 +171,7 @@ signals:
 	void failed(FileLoader *loader, bool started);
 
 protected:
-	using Queue = Storage::Downloader::Queue;
+	friend class Storage::Downloader;
 
 	enum class LocalStatus {
 		NotTried,
@@ -183,6 +180,10 @@ protected:
 		Loaded,
 	};
 
+	[[nodiscard]] MTP::DcId dcId() const {
+		return _dcId;
+	}
+
 	void readImage(const QSize &shrinkBox) const;
 
 	bool tryLoadLocal();
@@ -191,27 +192,21 @@ protected:
 	virtual std::optional<MediaKey> fileLocationKey() const = 0;
 	virtual void cancelRequests() = 0;
 
-	void startLoading();
-	void removeFromQueue();
 	void cancel(bool failed);
 
 	void notifyAboutProgress();
-	static void LoadNextFromQueue(not_null<Queue*> queue);
-	virtual bool loadPart() = 0;
+	[[nodiscard]] virtual bool readyToRequest() const = 0;
+	virtual void loadPart(int dcIndex) = 0;
 
 	bool writeResultPart(int offset, bytes::const_span buffer);
 	bool finalizeResult();
 	[[nodiscard]] QByteArray readLoadedPartBack(int offset, int size);
 
-	not_null<Storage::Downloader*> _downloader;
-	FileLoader *_prev = nullptr;
-	FileLoader *_next = nullptr;
-	int _priority = 0;
-	Queue *_queue = nullptr;
+	const MTP::DcId _dcId = 0;
+	const not_null<Storage::Downloader*> _downloader;
 
 	bool _autoLoading = false;
 	uint8 _cacheTag = 0;
-	bool _inQueue = false;
 	bool _finished = false;
 	bool _cancelled = false;
 	mutable LocalStatus _localStatus = LocalStatus::NotTried;
@@ -237,7 +232,7 @@ protected:
 
 class StorageImageLocation;
 class WebFileLocation;
-class mtpFileLoader : public FileLoader, public RPCSender {
+class mtpFileLoader final : public FileLoader, public RPCSender {
 public:
 	mtpFileLoader(
 		const StorageFileLocation &location,
@@ -277,6 +272,8 @@ public:
 	~mtpFileLoader();
 
 private:
+	friend class Downloader;
+
 	struct RequestData {
 		MTP::DcId dcId = 0;
 		int dcIndex = 0;
@@ -292,11 +289,12 @@ private:
 	std::optional<MediaKey> fileLocationKey() const override;
 	void cancelRequests() override;
 
-	MTP::DcId dcId() const;
-	RequestData prepareRequest(int offset) const;
+	[[nodiscard]] RequestData prepareRequest(int offset, int dcIndex) const;
+	void makeRequest(int offset, int dcIndex);
 	void makeRequest(int offset);
 
-	bool loadPart() override;
+	bool readyToRequest() const override;
+	void loadPart(int dcIndex) override;
 	void normalPartLoaded(const MTPupload_File &result, mtpRequestId requestId);
 	void webPartLoaded(const MTPupload_WebFile &result, mtpRequestId requestId);
 	void cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId);
@@ -334,7 +332,6 @@ private:
 		StorageFileLocation,
 		WebFileLocation,
 		GeoPointLocation> _location;
-
 	Data::FileOrigin _origin;
 
 	MTP::DcId _cdnDcId = 0;
@@ -349,7 +346,7 @@ private:
 
 class webFileLoaderPrivate;
 
-class webFileLoader : public FileLoader {
+class webFileLoader final : public FileLoader {
 public:
 	webFileLoader(
 		const QString &url,
@@ -370,11 +367,15 @@ public:
 
 	~webFileLoader();
 
-protected:
+private:
 	void cancelRequests() override;
 	Storage::Cache::Key cacheKey() const override;
 	std::optional<MediaKey> fileLocationKey() const override;
-	bool loadPart() override;
+	bool readyToRequest() const override;
+	void loadPart(int dcIndex) override;
+
+	void markAsSent();
+	void markAsNotSent();
 
 	QString _url;
 
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
index 12c929fee..aaab67bfa 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
@@ -37,6 +37,7 @@ StreamedFileDownloader::StreamedFileDownloader(
 	uint8 cacheTag)
 : FileLoader(
 	toFile,
+	dcId,
 	size,
 	locationType,
 	toCache,
@@ -59,8 +60,6 @@ StreamedFileDownloader::StreamedFileDownloader(
 			savePart(std::move(part));
 		}
 	}, _lifetime);
-
-	_queue = _downloader->queueForDc(dcId);
 }
 
 StreamedFileDownloader::~StreamedFileDownloader() {
@@ -98,21 +97,25 @@ std::optional<MediaKey> StreamedFileDownloader::fileLocationKey() const {
 }
 
 void StreamedFileDownloader::cancelRequests() {
-	//_partsRequested == std::count(
-	//	begin(_partIsSaved),
-	//	begin(_partIsSaved) + _nextPartIndex,
-	//	false);
-	_queue->queriesCount -= _partsRequested;
 	_partsRequested = 0;
 	_nextPartIndex = 0;
 
 	_reader->cancelForDownloader(this);
 }
 
-bool StreamedFileDownloader::loadPart() {
+bool StreamedFileDownloader::readyToRequest() const {
 	if (_finished || _nextPartIndex >= _partsCount) {
 		return false;
 	}
+	_nextPartIndex = std::find(
+		begin(_partIsSaved) + _nextPartIndex,
+		end(_partIsSaved),
+		false
+	) - begin(_partIsSaved);
+	return (_nextPartIndex < _partsCount);
+}
+
+void StreamedFileDownloader::loadPart(int dcIndex) {
 	const auto index = std::find(
 		begin(_partIsSaved) + _nextPartIndex,
 		end(_partIsSaved),
@@ -120,15 +123,11 @@ bool StreamedFileDownloader::loadPart() {
 	) - begin(_partIsSaved);
 	if (index == _partsCount) {
 		_nextPartIndex = _partsCount;
-		return false;
+		return;
 	}
 	_nextPartIndex = index + 1;
 	_reader->loadForDownloader(this, index * kPartSize);
-
 	++_partsRequested;
-	++_queue->queriesCount;
-
-	return true;
 }
 
 void StreamedFileDownloader::savePart(const LoadedPart &part) {
@@ -150,7 +149,6 @@ void StreamedFileDownloader::savePart(const LoadedPart &part) {
 
 	if (index < _nextPartIndex) {
 		--_partsRequested;
-		--_queue->queriesCount;
 	}
 	if (!writeResultPart(offset, bytes::make_span(part.bytes))) {
 		return;
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.h b/Telegram/SourceFiles/storage/streamed_file_downloader.h
index a223b7f5f..803bc3cde 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.h
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.h
@@ -49,7 +49,8 @@ private:
 	Cache::Key cacheKey() const override;
 	std::optional<MediaKey> fileLocationKey() const override;
 	void cancelRequests() override;
-	bool loadPart() override;
+	bool readyToRequest() const override;
+	void loadPart(int dcIndex) override;
 
 	void savePart(const Media::Streaming::LoadedPart &part);
 
@@ -60,7 +61,7 @@ private:
 	std::shared_ptr<Media::Streaming::Reader> _reader;
 
 	std::vector<bool> _partIsSaved; // vector<bool> :D
-	int _nextPartIndex = 0;
+	mutable int _nextPartIndex = 0;
 	int _partsCount = 0;
 	int _partsRequested = 0;
 	int _partsSaved = 0;

From 8535a579caa9f1b8a95124721fc49fd2b1b48338 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 3 Dec 2019 11:08:55 +0300
Subject: [PATCH 82/91] Fix by-word/paragraph text selection in WebPage.

---
 .../SourceFiles/history/view/media/history_view_web_page.cpp  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Telegram/SourceFiles/history/view/media/history_view_web_page.cpp b/Telegram/SourceFiles/history/view/media/history_view_web_page.cpp
index 6a096c283..cfb79881e 100644
--- a/Telegram/SourceFiles/history/view/media/history_view_web_page.cpp
+++ b/Telegram/SourceFiles/history/view/media/history_view_web_page.cpp
@@ -678,12 +678,12 @@ TextSelection WebPage::adjustSelection(TextSelection selection, TextSelectType t
 		return _siteName.adjustSelection(selection, type);
 	}
 
+	auto titlesLength = _siteName.length() + _title.length();
 	auto titleSelection = _title.adjustSelection(toTitleSelection(selection), type);
-	if ((!_siteNameLines && !_descriptionLines) || (selection.from >= _siteName.length() && selection.to <= _description.length())) {
+	if ((!_siteNameLines && !_descriptionLines) || (selection.from >= _siteName.length() && selection.to <= titlesLength)) {
 		return fromTitleSelection(titleSelection);
 	}
 
-	auto titlesLength = _siteName.length() + _title.length();
 	auto descriptionSelection = _description.adjustSelection(toDescriptionSelection(selection), type);
 	if ((!_siteNameLines && !_titleLines) || selection.from >= titlesLength) {
 		return fromDescriptionSelection(descriptionSelection);

From fb86bb579befb170a57b8cbffe1d49aea97dd5e6 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 3 Dec 2019 15:45:35 +0300
Subject: [PATCH 83/91] Correctly track DC index in Downloader-s.

---
 Telegram/SourceFiles/main/main_session.cpp    |   2 +-
 Telegram/SourceFiles/main/main_session.h      |   6 +-
 .../media_streaming_loader_mtproto.cpp        |   2 +-
 .../media_streaming_loader_mtproto.h          |   6 +-
 .../SourceFiles/storage/file_download.cpp     | 160 ++++++++----------
 Telegram/SourceFiles/storage/file_download.h  |  76 +++++----
 6 files changed, 123 insertions(+), 129 deletions(-)

diff --git a/Telegram/SourceFiles/main/main_session.cpp b/Telegram/SourceFiles/main/main_session.cpp
index eceeaa826..b41225227 100644
--- a/Telegram/SourceFiles/main/main_session.cpp
+++ b/Telegram/SourceFiles/main/main_session.cpp
@@ -44,7 +44,7 @@ Session::Session(
 , _autoLockTimer([=] { checkAutoLock(); })
 , _api(std::make_unique<ApiWrap>(this))
 , _calls(std::make_unique<Calls::Instance>(this))
-, _downloader(std::make_unique<Storage::Downloader>(_api.get()))
+, _downloader(std::make_unique<Storage::DownloadManager>(_api.get()))
 , _uploader(std::make_unique<Storage::Uploader>(_api.get()))
 , _storage(std::make_unique<Storage::Facade>())
 , _notifications(std::make_unique<Window::Notifications::System>(this))
diff --git a/Telegram/SourceFiles/main/main_session.h b/Telegram/SourceFiles/main/main_session.h
index ed12fcc94..117744c92 100644
--- a/Telegram/SourceFiles/main/main_session.h
+++ b/Telegram/SourceFiles/main/main_session.h
@@ -29,7 +29,7 @@ class Session;
 } // namespace Data
 
 namespace Storage {
-class Downloader;
+class DownloadManager;
 class Uploader;
 class Facade;
 } // namespace Storage
@@ -80,7 +80,7 @@ public:
 	}
 	bool validateSelf(const MTPUser &user);
 
-	[[nodiscard]] Storage::Downloader &downloader() {
+	[[nodiscard]] Storage::DownloadManager &downloader() {
 		return *_downloader;
 	}
 	[[nodiscard]] Storage::Uploader &uploader() {
@@ -145,7 +145,7 @@ private:
 
 	const std::unique_ptr<ApiWrap> _api;
 	const std::unique_ptr<Calls::Instance> _calls;
-	const std::unique_ptr<Storage::Downloader> _downloader;
+	const std::unique_ptr<Storage::DownloadManager> _downloader;
 	const std::unique_ptr<Storage::Uploader> _uploader;
 	const std::unique_ptr<Storage::Facade> _storage;
 	const std::unique_ptr<Window::Notifications::System> _notifications;
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
index 95b5404da..ca93ac426 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
@@ -21,7 +21,7 @@ constexpr auto kMaxConcurrentRequests = 4;
 } // namespace
 
 LoaderMtproto::LoaderMtproto(
-	not_null<Storage::Downloader*> owner,
+	not_null<Storage::DownloadManager*> owner,
 	const StorageFileLocation &location,
 	int size,
 	Data::FileOrigin origin)
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
index bd9d1ef0e..0a32717df 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
@@ -12,7 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_file_origin.h"
 
 namespace Storage {
-class Downloader;
+class DownloadManager;
 } // namespace Storage
 
 namespace Media {
@@ -21,7 +21,7 @@ namespace Streaming {
 class LoaderMtproto : public Loader, public base::has_weak_ptr {
 public:
 	LoaderMtproto(
-		not_null<Storage::Downloader*> owner,
+		not_null<Storage::DownloadManager*> owner,
 		const StorageFileLocation &location,
 		int size,
 		Data::FileOrigin origin);
@@ -61,7 +61,7 @@ private:
 	void cancelForOffset(int offset);
 	void changeRequestedAmount(int index, int amount);
 
-	const not_null<Storage::Downloader*> _owner;
+	const not_null<Storage::DownloadManager*> _owner;
 
 	// _location can be changed with an updated file_reference.
 	StorageFileLocation _location;
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index 0f2d647eb..9dbef1d25 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -45,7 +45,7 @@ constexpr auto kPartSize = 128 * 1024;
 
 } // namespace
 
-void Downloader::Queue::enqueue(not_null<FileLoader*> loader) {
+void DownloadManager::Queue::enqueue(not_null<Downloader*> loader) {
 	const auto i = ranges::find(_loaders, loader);
 	if (i != end(_loaders)) {
 		return;
@@ -56,14 +56,14 @@ void Downloader::Queue::enqueue(not_null<FileLoader*> loader) {
 		end(_previousGeneration));
 }
 
-void Downloader::Queue::remove(not_null<FileLoader*> loader) {
+void DownloadManager::Queue::remove(not_null<Downloader*> loader) {
 	_loaders.erase(ranges::remove(_loaders, loader), end(_loaders));
 	_previousGeneration.erase(
 		ranges::remove(_previousGeneration, loader),
 		end(_previousGeneration));
 }
 
-void Downloader::Queue::resetGeneration() {
+void DownloadManager::Queue::resetGeneration() {
 	if (!_previousGeneration.empty()) {
 		_loaders.reserve(_loaders.size() + _previousGeneration.size());
 		std::copy(
@@ -75,22 +75,22 @@ void Downloader::Queue::resetGeneration() {
 	std::swap(_loaders, _previousGeneration);
 }
 
-FileLoader *Downloader::Queue::nextLoader() const {
+Downloader *DownloadManager::Queue::nextLoader() const {
 	auto &&all = ranges::view::concat(_loaders, _previousGeneration);
 	const auto i = ranges::find(all, true, &FileLoader::readyToRequest);
 	return (i != all.end()) ? i->get() : nullptr;
 }
 
-Downloader::Downloader(not_null<ApiWrap*> api)
+DownloadManager::DownloadManager(not_null<ApiWrap*> api)
 : _api(api)
 , _killDownloadSessionsTimer([=] { killDownloadSessions(); }) {
 }
 
-Downloader::~Downloader() {
+DownloadManager::~DownloadManager() {
 	killDownloadSessions();
 }
 
-void Downloader::enqueue(not_null<FileLoader*> loader) {
+void DownloadManager::enqueue(not_null<Downloader*> loader) {
 	const auto dcId = loader->dcId();
 	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).enqueue(loader);
 	if (!_resettingGeneration) {
@@ -102,13 +102,13 @@ void Downloader::enqueue(not_null<FileLoader*> loader) {
 	checkSendNext();
 }
 
-void Downloader::remove(not_null<FileLoader*> loader) {
+void DownloadManager::remove(not_null<Downloader*> loader) {
 	const auto dcId = loader->dcId();
 	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).remove(loader);
 	crl::on_main(&_api->session(), [=] { checkSendNext(); });
 }
 
-void Downloader::resetGeneration() {
+void DownloadManager::resetGeneration() {
 	_resettingGeneration = false;
 	for (auto &[dcId, queue] : _mtprotoLoaders) {
 		queue.resetGeneration();
@@ -116,7 +116,7 @@ void Downloader::resetGeneration() {
 	_webLoaders.resetGeneration();
 }
 
-void Downloader::checkSendNext() {
+void DownloadManager::checkSendNext() {
 	for (auto &[dcId, queue] : _mtprotoLoaders) {
 		const auto bestIndex = [&] {
 			const auto i = _requestedBytesAmount.find(dcId);
@@ -143,7 +143,7 @@ void Downloader::checkSendNext() {
 	}
 }
 
-void Downloader::requestedAmountIncrement(
+void DownloadManager::requestedAmountIncrement(
 		MTP::DcId dcId,
 		int index,
 		int amount) {
@@ -166,14 +166,14 @@ void Downloader::requestedAmountIncrement(
 	}
 }
 
-int Downloader::chooseDcIndexForRequest(MTP::DcId dcId) {
+int DownloadManager::chooseDcIndexForRequest(MTP::DcId dcId) {
 	const auto i = _requestedBytesAmount.find(dcId);
 	return (i != end(_requestedBytesAmount))
 		? (ranges::min_element(i->second) - begin(i->second))
 		: 0;
 }
 
-void Downloader::killDownloadSessionsStart(MTP::DcId dcId) {
+void DownloadManager::killDownloadSessionsStart(MTP::DcId dcId) {
 	if (!_killDownloadSessionTimes.contains(dcId)) {
 		_killDownloadSessionTimes.emplace(
 			dcId,
@@ -184,7 +184,7 @@ void Downloader::killDownloadSessionsStart(MTP::DcId dcId) {
 	}
 }
 
-void Downloader::killDownloadSessionsStop(MTP::DcId dcId) {
+void DownloadManager::killDownloadSessionsStop(MTP::DcId dcId) {
 	_killDownloadSessionTimes.erase(dcId);
 	if (_killDownloadSessionTimes.empty()
 		&& _killDownloadSessionsTimer.isActive()) {
@@ -192,7 +192,7 @@ void Downloader::killDownloadSessionsStop(MTP::DcId dcId) {
 	}
 }
 
-void Downloader::killDownloadSessions() {
+void DownloadManager::killDownloadSessions() {
 	const auto now = crl::now();
 	auto left = kKillSessionTimeout;
 	for (auto i = _killDownloadSessionTimes.begin(); i != _killDownloadSessionTimes.end(); ) {
@@ -669,8 +669,7 @@ void mtpFileLoader::refreshFileReferenceFrom(
 		cancel(true);
 		return;
 	}
-	const auto offset = finishSentRequestGetOffset(requestId);
-	makeRequest(offset);
+	makeRequest(finishSentRequest(requestId));
 }
 
 bool mtpFileLoader::readyToRequest() const {
@@ -683,28 +682,17 @@ bool mtpFileLoader::readyToRequest() const {
 void mtpFileLoader::loadPart(int dcIndex) {
 	Expects(readyToRequest());
 
-	makeRequest(_nextRequestOffset, dcIndex);
+	makeRequest({ _nextRequestOffset, dcIndex });
 	_nextRequestOffset += Storage::kPartSize;
 }
 
-mtpFileLoader::RequestData mtpFileLoader::prepareRequest(
-		int offset,
-		int dcIndex) const {
-	auto result = RequestData();
-	result.dcId = _cdnDcId ? _cdnDcId : dcId();
-	result.dcIndex = dcIndex;
-	result.offset = offset;
-	return result;
-}
-
 mtpRequestId mtpFileLoader::sendRequest(const RequestData &requestData) {
 	const auto offset = requestData.offset;
 	const auto limit = Storage::kPartSize;
 	const auto shiftedDcId = MTP::downloadDcId(
-		requestData.dcId,
+		_cdnDcId ? _cdnDcId : dcId(),
 		requestData.dcIndex);
 	if (_cdnDcId) {
-		Assert(requestData.dcId == _cdnDcId);
 		return MTP::send(
 			MTPupload_GetCdnFile(
 				MTP_bytes(_cdnToken),
@@ -761,17 +749,12 @@ mtpRequestId mtpFileLoader::sendRequest(const RequestData &requestData) {
 	});
 }
 
-void mtpFileLoader::makeRequest(int offset, int dcIndex) {
+void mtpFileLoader::makeRequest(const RequestData &requestData) {
 	Expects(!_finished);
 
-	auto requestData = prepareRequest(offset, dcIndex);
 	placeSentRequest(sendRequest(requestData), requestData);
 }
 
-void mtpFileLoader::makeRequest(int offset) {
-	makeRequest(offset, _downloader->chooseDcIndexForRequest(dcId()));
-}
-
 void mtpFileLoader::requestMoreCdnFileHashes() {
 	Expects(!_finished);
 
@@ -779,18 +762,14 @@ void mtpFileLoader::requestMoreCdnFileHashes() {
 		return;
 	}
 
-	auto offset = _cdnUncheckedParts.cbegin()->first;
-	auto requestData = RequestData();
-	requestData.dcId = dcId();
-	requestData.dcIndex = 0;
-	requestData.offset = offset;
-	auto shiftedDcId = MTP::downloadDcId(
-		requestData.dcId,
+	const auto requestData = _cdnUncheckedParts.cbegin()->first;
+	const auto shiftedDcId = MTP::downloadDcId(
+		dcId(),
 		requestData.dcIndex);
-	auto requestId = _cdnHashesRequestId = MTP::send(
+	const auto requestId = _cdnHashesRequestId = MTP::send(
 		MTPupload_GetCdnFileHashes(
 			MTP_bytes(_cdnToken),
-			MTP_int(offset)),
+			MTP_int(requestData.offset)),
 		rpcDone(&mtpFileLoader::getCdnFileHashesDone),
 		rpcFail(&mtpFileLoader::cdnPartFailed),
 		shiftedDcId);
@@ -801,21 +780,20 @@ void mtpFileLoader::normalPartLoaded(
 		const MTPupload_File &result,
 		mtpRequestId requestId) {
 	Expects(!_finished);
-	Expects(result.type() == mtpc_upload_fileCdnRedirect || result.type() == mtpc_upload_file);
 
-	auto offset = finishSentRequestGetOffset(requestId);
-	if (result.type() == mtpc_upload_fileCdnRedirect) {
-		return switchToCDN(offset, result.c_upload_fileCdnRedirect());
-	}
-	auto buffer = bytes::make_span(result.c_upload_file().vbytes().v);
-	return partLoaded(offset, buffer);
+	const auto requestData = finishSentRequest(requestId);
+	result.match([&](const MTPDupload_fileCdnRedirect &data) {
+		switchToCDN(requestData, data);
+	}, [&](const MTPDupload_file &data) {
+		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
+	});
 }
 
 void mtpFileLoader::webPartLoaded(
 		const MTPupload_WebFile &result,
 		mtpRequestId requestId) {
 	result.match([&](const MTPDupload_webFile &data) {
-		const auto offset = finishSentRequestGetOffset(requestId);
+		const auto requestData = finishSentRequest(requestId);
 		if (!_size) {
 			_size = data.vsize().v;
 		} else if (data.vsize().v != _size) {
@@ -826,21 +804,17 @@ void mtpFileLoader::webPartLoaded(
 			cancel(true);
 			return;
 		}
-		partLoaded(offset, bytes::make_span(data.vbytes().v));
+		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
 	});
 }
 
 void mtpFileLoader::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId) {
 	Expects(!_finished);
 
-	const auto offset = finishSentRequestGetOffset(requestId);
+	const auto requestData = finishSentRequest(requestId);
 	result.match([&](const MTPDupload_cdnFileReuploadNeeded &data) {
-		auto requestData = RequestData();
-		requestData.dcId = dcId();
-		requestData.dcIndex = 0;
-		requestData.offset = offset;
 		const auto shiftedDcId = MTP::downloadDcId(
-			requestData.dcId,
+			dcId(),
 			requestData.dcIndex);
 		const auto requestId = MTP::send(
 			MTPupload_ReuploadCdnFile(
@@ -860,7 +834,7 @@ void mtpFileLoader::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId
 		auto ivec = bytes::make_span(state.ivec);
 		std::copy(iv.begin(), iv.end(), ivec.begin());
 
-		auto counterOffset = static_cast<uint32>(offset) >> 4;
+		auto counterOffset = static_cast<uint32>(requestData.offset) >> 4;
 		state.ivec[15] = static_cast<uchar>(counterOffset & 0xFF);
 		state.ivec[14] = static_cast<uchar>((counterOffset >> 8) & 0xFF);
 		state.ivec[13] = static_cast<uchar>((counterOffset >> 16) & 0xFF);
@@ -870,19 +844,20 @@ void mtpFileLoader::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId
 		auto buffer = bytes::make_detached_span(decryptInPlace);
 		MTP::aesCtrEncrypt(buffer, key.data(), &state);
 
-		switch (checkCdnFileHash(offset, buffer)) {
+		switch (checkCdnFileHash(requestData.offset, buffer)) {
 		case CheckCdnHashResult::NoHash: {
-			_cdnUncheckedParts.emplace(offset, decryptInPlace);
+			_cdnUncheckedParts.emplace(requestData, decryptInPlace);
 			requestMoreCdnFileHashes();
 		} return;
 
 		case CheckCdnHashResult::Invalid: {
-			LOG(("API Error: Wrong cdnFileHash for offset %1.").arg(offset));
+			LOG(("API Error: Wrong cdnFileHash for offset %1."
+				).arg(requestData.offset));
 			cancel(true);
 		} return;
 
 		case CheckCdnHashResult::Good: {
-			partLoaded(offset, buffer);
+			partLoaded(requestData.offset, buffer);
 		} return;
 		}
 		Unexpected("Result of checkCdnFileHash()");
@@ -907,9 +882,9 @@ mtpFileLoader::CheckCdnHashResult mtpFileLoader::checkCdnFileHash(
 void mtpFileLoader::reuploadDone(
 		const MTPVector<MTPFileHash> &result,
 		mtpRequestId requestId) {
-	auto offset = finishSentRequestGetOffset(requestId);
+	const auto requestData = finishSentRequest(requestId);
 	addCdnHashes(result.v);
-	makeRequest(offset);
+	makeRequest(requestData);
 }
 
 void mtpFileLoader::getCdnFileHashesDone(
@@ -920,27 +895,28 @@ void mtpFileLoader::getCdnFileHashesDone(
 
 	_cdnHashesRequestId = 0;
 
-	const auto offset = finishSentRequestGetOffset(requestId);
+	const auto requestData = finishSentRequest(requestId);
 	addCdnHashes(result.v);
 	auto someMoreChecked = false;
 	for (auto i = _cdnUncheckedParts.begin(); i != _cdnUncheckedParts.cend();) {
-		const auto uncheckedOffset = i->first;
+		const auto uncheckedData = i->first;
 		const auto uncheckedBytes = bytes::make_span(i->second);
 
-		switch (checkCdnFileHash(uncheckedOffset, uncheckedBytes)) {
+		switch (checkCdnFileHash(uncheckedData.offset, uncheckedBytes)) {
 		case CheckCdnHashResult::NoHash: {
 			++i;
 		} break;
 
 		case CheckCdnHashResult::Invalid: {
-			LOG(("API Error: Wrong cdnFileHash for offset %1.").arg(offset));
+			LOG(("API Error: Wrong cdnFileHash for offset %1."
+				).arg(uncheckedData.offset));
 			cancel(true);
 			return;
 		} break;
 
 		case CheckCdnHashResult::Good: {
 			someMoreChecked = true;
-			const auto goodOffset = uncheckedOffset;
+			const auto goodOffset = uncheckedData.offset;
 			const auto goodBytes = std::move(i->second);
 			const auto weak = QPointer<mtpFileLoader>(this);
 			i = _cdnUncheckedParts.erase(i);
@@ -967,7 +943,7 @@ void mtpFileLoader::getCdnFileHashesDone(
 	LOG(("API Error: "
 		"Could not find cdnFileHash for offset %1 "
 		"after getCdnFileHashes request."
-		).arg(offset));
+		).arg(requestData.offset));
 	cancel(true);
 }
 
@@ -977,24 +953,25 @@ void mtpFileLoader::placeSentRequest(
 	Expects(!_finished);
 
 	_downloader->requestedAmountIncrement(
-		requestData.dcId,
+		dcId(),
 		requestData.dcIndex,
 		Storage::kPartSize);
 	_sentRequests.emplace(requestId, requestData);
 }
 
-int mtpFileLoader::finishSentRequestGetOffset(mtpRequestId requestId) {
+auto mtpFileLoader::finishSentRequest(mtpRequestId requestId)
+-> RequestData {
 	auto it = _sentRequests.find(requestId);
 	Assert(it != _sentRequests.cend());
 
-	auto requestData = it->second;
+	const auto result = it->second;
 	_downloader->requestedAmountIncrement(
-		requestData.dcId,
-		requestData.dcIndex,
+		dcId(),
+		result.dcIndex,
 		-Storage::kPartSize);
 	_sentRequests.erase(it);
 
-	return requestData.offset;
+	return result;
 }
 
 bool mtpFileLoader::feedPart(int offset, bytes::const_span buffer) {
@@ -1061,9 +1038,9 @@ bool mtpFileLoader::cdnPartFailed(
 	}
 	if (error.type() == qstr("FILE_TOKEN_INVALID")
 		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
-		auto offset = finishSentRequestGetOffset(requestId);
+		const auto requestData = finishSentRequest(requestId);
 		changeCDNParams(
-			offset,
+			requestData,
 			0,
 			QByteArray(),
 			QByteArray(),
@@ -1078,15 +1055,15 @@ void mtpFileLoader::cancelRequests() {
 	while (!_sentRequests.empty()) {
 		auto requestId = _sentRequests.begin()->first;
 		MTP::cancel(requestId);
-		finishSentRequestGetOffset(requestId);
+		[[maybe_unused]] const auto data = finishSentRequest(requestId);
 	}
 }
 
 void mtpFileLoader::switchToCDN(
-		int offset,
+		const RequestData &requestData,
 		const MTPDupload_fileCdnRedirect &redirect) {
 	changeCDNParams(
-		offset,
+		requestData,
 		redirect.vdc_id().v,
 		redirect.vfile_token().v,
 		redirect.vencryption_key().v,
@@ -1105,7 +1082,7 @@ void mtpFileLoader::addCdnHashes(const QVector<MTPFileHash> &hashes) {
 }
 
 void mtpFileLoader::changeCDNParams(
-		int offset,
+		const RequestData &requestData,
 		MTP::DcId dcId,
 		const QByteArray &token,
 		const QByteArray &encryptionKey,
@@ -1130,19 +1107,18 @@ void mtpFileLoader::changeCDNParams(
 	addCdnHashes(hashes);
 
 	if (resendAllRequests && !_sentRequests.empty()) {
-		auto resendOffsets = std::vector<int>();
-		resendOffsets.reserve(_sentRequests.size());
+		auto resendRequests = std::vector<RequestData>();
+		resendRequests.reserve(_sentRequests.size());
 		while (!_sentRequests.empty()) {
 			auto requestId = _sentRequests.begin()->first;
 			MTP::cancel(requestId);
-			auto resendOffset = finishSentRequestGetOffset(requestId);
-			resendOffsets.push_back(resendOffset);
+			resendRequests.push_back(finishSentRequest(requestId));
 		}
-		for (auto resendOffset : resendOffsets) {
-			makeRequest(resendOffset);
+		for (const auto &requestData : resendRequests) {
+			makeRequest(requestData);
 		}
 	}
-	makeRequest(offset);
+	makeRequest(requestData);
 }
 
 Storage::Cache::Key mtpFileLoader::cacheKey() const {
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index cd098555e..c4702611a 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -16,7 +16,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtNetwork/QNetworkReply>
 
 class ApiWrap;
-class FileLoader;
 
 namespace Main {
 class Session;
@@ -36,17 +35,27 @@ constexpr auto kMaxWallPaperInMemory = kMaxFileInMemory;
 constexpr auto kMaxAnimationInMemory = kMaxFileInMemory; // 10 MB gif and mp4 animations held in memory while playing
 constexpr auto kMaxWallPaperDimension = 4096; // 4096x4096 is max area.
 
-class Downloader final : public base::has_weak_ptr {
+class Downloader {
 public:
-	explicit Downloader(not_null<ApiWrap*> api);
-	~Downloader();
+	virtual ~Downloader() = default;
+
+	[[nodiscard]] virtual MTP::DcId dcId() const = 0;
+	[[nodiscard]] virtual bool readyToRequest() const = 0;
+	[[nodiscard]] virtual void loadPart(int dcIndex) = 0;
+
+};
+
+class DownloadManager final : public base::has_weak_ptr {
+public:
+	explicit DownloadManager(not_null<ApiWrap*> api);
+	~DownloadManager();
 
 	[[nodiscard]] ApiWrap &api() const {
 		return *_api;
 	}
 
-	void enqueue(not_null<FileLoader*> loader);
-	void remove(not_null<FileLoader*> loader);
+	void enqueue(not_null<Downloader*> loader);
+	void remove(not_null<Downloader*> loader);
 
 	[[nodiscard]] base::Observable<void> &taskFinished() {
 		return _taskFinishedObservable;
@@ -59,14 +68,14 @@ public:
 private:
 	class Queue final {
 	public:
-		void enqueue(not_null<FileLoader*> loader);
-		void remove(not_null<FileLoader*> loader);
+		void enqueue(not_null<Downloader*> loader);
+		void remove(not_null<Downloader*> loader);
 		void resetGeneration();
-		[[nodiscard]] FileLoader *nextLoader() const;
+		[[nodiscard]] Downloader *nextLoader() const;
 
 	private:
-		std::vector<not_null<FileLoader*>> _loaders;
-		std::vector<not_null<FileLoader*>> _previousGeneration;
+		std::vector<not_null<Downloader*>> _loaders;
+		std::vector<not_null<Downloader*>> _previousGeneration;
 
 	};
 
@@ -105,7 +114,7 @@ struct StorageImageSaved {
 
 };
 
-class FileLoader : public QObject {
+class FileLoader : public QObject, public Storage::Downloader {
 	Q_OBJECT
 
 public:
@@ -171,7 +180,7 @@ signals:
 	void failed(FileLoader *loader, bool started);
 
 protected:
-	friend class Storage::Downloader;
+	friend class Storage::DownloadManager;
 
 	enum class LocalStatus {
 		NotTried,
@@ -180,7 +189,7 @@ protected:
 		Loaded,
 	};
 
-	[[nodiscard]] MTP::DcId dcId() const {
+	MTP::DcId dcId() const override {
 		return _dcId;
 	}
 
@@ -195,15 +204,13 @@ protected:
 	void cancel(bool failed);
 
 	void notifyAboutProgress();
-	[[nodiscard]] virtual bool readyToRequest() const = 0;
-	virtual void loadPart(int dcIndex) = 0;
 
 	bool writeResultPart(int offset, bytes::const_span buffer);
 	bool finalizeResult();
 	[[nodiscard]] QByteArray readLoadedPartBack(int offset, int size);
 
 	const MTP::DcId _dcId = 0;
-	const not_null<Storage::Downloader*> _downloader;
+	const not_null<Storage::DownloadManager*> _downloader;
 
 	bool _autoLoading = false;
 	uint8 _cacheTag = 0;
@@ -272,12 +279,15 @@ public:
 	~mtpFileLoader();
 
 private:
-	friend class Downloader;
+	friend class DownloadManager;
 
 	struct RequestData {
-		MTP::DcId dcId = 0;
-		int dcIndex = 0;
 		int offset = 0;
+		int dcIndex = 0;
+
+		inline bool operator<(const RequestData &other) const {
+			return offset < other.offset;
+		}
 	};
 	struct CdnFileHash {
 		CdnFileHash(int limit, QByteArray hash) : limit(limit), hash(hash) {
@@ -289,9 +299,7 @@ private:
 	std::optional<MediaKey> fileLocationKey() const override;
 	void cancelRequests() override;
 
-	[[nodiscard]] RequestData prepareRequest(int offset, int dcIndex) const;
-	void makeRequest(int offset, int dcIndex);
-	void makeRequest(int offset);
+	void makeRequest(const RequestData &requestData);
 
 	bool readyToRequest() const override;
 	void loadPart(int dcIndex) override;
@@ -310,11 +318,21 @@ private:
 	bool cdnPartFailed(const RPCError &error, mtpRequestId requestId);
 
 	mtpRequestId sendRequest(const RequestData &requestData);
-	void placeSentRequest(mtpRequestId requestId, const RequestData &requestData);
-	int finishSentRequestGetOffset(mtpRequestId requestId);
-	void switchToCDN(int offset, const MTPDupload_fileCdnRedirect &redirect);
+	void placeSentRequest(
+		mtpRequestId requestId,
+		const RequestData &requestData);
+	[[nodiscard]] RequestData finishSentRequest(mtpRequestId requestId);
+	void switchToCDN(
+		const RequestData &requestData,
+		const MTPDupload_fileCdnRedirect &redirect);
 	void addCdnHashes(const QVector<MTPFileHash> &hashes);
-	void changeCDNParams(int offset, MTP::DcId dcId, const QByteArray &token, const QByteArray &encryptionKey, const QByteArray &encryptionIV, const QVector<MTPFileHash> &hashes);
+	void changeCDNParams(
+		const RequestData &requestData,
+		MTP::DcId dcId,
+		const QByteArray &token,
+		const QByteArray &encryptionKey,
+		const QByteArray &encryptionIV,
+		const QVector<MTPFileHash> &hashes);
 
 	enum class CheckCdnHashResult {
 		NoHash,
@@ -338,8 +356,8 @@ private:
 	QByteArray _cdnToken;
 	QByteArray _cdnEncryptionKey;
 	QByteArray _cdnEncryptionIV;
-	std::map<int, CdnFileHash> _cdnFileHashes;
-	std::map<int, QByteArray> _cdnUncheckedParts;
+	base::flat_map<int, CdnFileHash> _cdnFileHashes;
+	base::flat_map<RequestData, QByteArray> _cdnUncheckedParts;
 	mtpRequestId _cdnHashesRequestId = 0;
 
 };

From cb2c6e4b891a5703a927c9a183ae722ffe54fab3 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 3 Dec 2019 17:50:25 +0300
Subject: [PATCH 84/91] Change QR code phrase.

---
 Telegram/Resources/langs/lang.strings | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Telegram/Resources/langs/lang.strings b/Telegram/Resources/langs/lang.strings
index 30ea2a818..6adb39522 100644
--- a/Telegram/Resources/langs/lang.strings
+++ b/Telegram/Resources/langs/lang.strings
@@ -180,7 +180,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 "lng_intro_qr_title" = "Scan From Mobile Telegram";
 "lng_intro_qr_step1" = "**1.** Open Telegram on your phone";
-"lng_intro_qr_step2" = "**2.** Go to **Settings** and tap \"Scan QR code\"";
+"lng_intro_qr_step2" = "**2.** Go to Settings > Devices > Scan QR Code";
 "lng_intro_qr_step3" = "**3.** Scan this image to Log In";
 "lng_intro_qr_skip" = "Or log in using your phone number";
 

From 3ae2986c253ed4efdcfc48949f53f7343177b49c Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 4 Dec 2019 09:51:21 +0300
Subject: [PATCH 85/91] Allow variable count of download sessions.

---
 .../media/streaming/media_streaming_loader.h  |  2 +-
 .../media_streaming_loader_local.cpp          |  2 +-
 .../streaming/media_streaming_loader_local.h  |  2 +-
 .../media_streaming_loader_mtproto.cpp        |  2 +-
 .../media_streaming_loader_mtproto.h          |  2 +-
 .../streaming/media_streaming_reader.cpp      |  4 ++--
 .../media/streaming/media_streaming_reader.h  |  5 ++--
 Telegram/SourceFiles/mtproto/facade.h         |  7 +++---
 .../SourceFiles/mtproto/session_private.cpp   |  2 --
 .../SourceFiles/storage/file_download.cpp     | 24 +++++++++++++------
 Telegram/SourceFiles/storage/file_download.h  |  5 ++--
 11 files changed, 32 insertions(+), 25 deletions(-)

diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader.h
index df476872b..51c486e7b 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader.h
@@ -40,7 +40,7 @@ public:
 	[[nodiscard]] virtual rpl::producer<LoadedPart> parts() const = 0;
 
 	virtual void attachDownloader(
-		Storage::StreamedFileDownloader *downloader) = 0;
+		not_null<Storage::StreamedFileDownloader*> downloader) = 0;
 	virtual void clearAttachedDownloader() = 0;
 
 	virtual ~Loader() = default;
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.cpp
index f5620c1c8..00cef555d 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.cpp
@@ -79,7 +79,7 @@ rpl::producer<LoadedPart> LoaderLocal::parts() const {
 }
 
 void LoaderLocal::attachDownloader(
-		Storage::StreamedFileDownloader *downloader) {
+		not_null<Storage::StreamedFileDownloader*> downloader) {
 	Unexpected("Downloader attached to a local streaming loader.");
 }
 
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.h
index d741b18fc..b7436e2a5 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_local.h
@@ -33,7 +33,7 @@ public:
 	[[nodiscard]] rpl::producer<LoadedPart> parts() const override;
 
 	void attachDownloader(
-		Storage::StreamedFileDownloader *downloader) override;
+		not_null<Storage::StreamedFileDownloader*> downloader) override;
 	void clearAttachedDownloader() override;
 
 private:
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
index ca93ac426..6a713909b 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
@@ -91,7 +91,7 @@ void LoaderMtproto::cancelForOffset(int offset) {
 }
 
 void LoaderMtproto::attachDownloader(
-		Storage::StreamedFileDownloader *downloader) {
+		not_null<Storage::StreamedFileDownloader*> downloader) {
 	_downloader = downloader;
 }
 
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
index 0a32717df..a7f16f4f8 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
@@ -40,7 +40,7 @@ public:
 	[[nodiscard]] rpl::producer<LoadedPart> parts() const override;
 
 	void attachDownloader(
-		Storage::StreamedFileDownloader *downloader) override;
+		not_null<Storage::StreamedFileDownloader*> downloader) override;
 	void clearAttachedDownloader() override;
 
 private:
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_reader.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_reader.cpp
index 79bdfcdd1..15d41aad8 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_reader.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_reader.cpp
@@ -906,7 +906,7 @@ rpl::producer<LoadedPart> Reader::partsForDownloader() const {
 }
 
 void Reader::loadForDownloader(
-		Storage::StreamedFileDownloader *downloader,
+		not_null<Storage::StreamedFileDownloader*> downloader,
 		int offset) {
 	if (_attachedDownloader != downloader) {
 		if (_attachedDownloader) {
@@ -931,7 +931,7 @@ void Reader::doneForDownloader(int offset) {
 }
 
 void Reader::cancelForDownloader(
-		Storage::StreamedFileDownloader *downloader) {
+		not_null<Storage::StreamedFileDownloader*> downloader) {
 	if (_attachedDownloader == downloader) {
 		_downloaderOffsetRequests.take();
 		_attachedDownloader = nullptr;
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_reader.h b/Telegram/SourceFiles/media/streaming/media_streaming_reader.h
index 7ea333987..45f24187c 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_reader.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_reader.h
@@ -61,10 +61,11 @@ public:
 	void stopStreaming(bool stillActive = false);
 	[[nodiscard]] rpl::producer<LoadedPart> partsForDownloader() const;
 	void loadForDownloader(
-		Storage::StreamedFileDownloader *downloader,
+		not_null<Storage::StreamedFileDownloader*> downloader,
 		int offset);
 	void doneForDownloader(int offset);
-	void cancelForDownloader(Storage::StreamedFileDownloader *downloader);
+	void cancelForDownloader(
+		not_null<Storage::StreamedFileDownloader*> downloader);
 
 	~Reader();
 
diff --git a/Telegram/SourceFiles/mtproto/facade.h b/Telegram/SourceFiles/mtproto/facade.h
index 75868ce83..037085366 100644
--- a/Telegram/SourceFiles/mtproto/facade.h
+++ b/Telegram/SourceFiles/mtproto/facade.h
@@ -34,13 +34,13 @@ constexpr ShiftedDcId updaterDcId(DcId dcId) {
 	return ShiftDcId(dcId, kUpdaterDcShift);
 }
 
-constexpr auto kDownloadSessionsCount = 2;
 constexpr auto kUploadSessionsCount = 2;
 
 namespace details {
 
 constexpr ShiftedDcId downloadDcId(DcId dcId, int index) {
-	static_assert(kDownloadSessionsCount < kMaxMediaDcCount, "Too large MTPDownloadSessionsCount!");
+	Expects(index < kMaxMediaDcCount);
+
 	return ShiftDcId(dcId, kBaseDownloadDcShift + index);
 };
 
@@ -48,13 +48,12 @@ constexpr ShiftedDcId downloadDcId(DcId dcId, int index) {
 
 // send(req, callbacks, MTP::downloadDcId(dc, index)) - for download shifted dc id
 inline ShiftedDcId downloadDcId(DcId dcId, int index) {
-	Expects(index >= 0 && index < kDownloadSessionsCount);
 	return details::downloadDcId(dcId, index);
 }
 
 inline constexpr bool isDownloadDcId(ShiftedDcId shiftedDcId) {
 	return (shiftedDcId >= details::downloadDcId(0, 0))
-		&& (shiftedDcId < details::downloadDcId(0, kDownloadSessionsCount - 1) + kDcShift);
+		&& (shiftedDcId < details::downloadDcId(0, kMaxMediaDcCount - 1) + kDcShift);
 }
 
 inline bool isCdnDc(MTPDdcOption::Flags flags) {
diff --git a/Telegram/SourceFiles/mtproto/session_private.cpp b/Telegram/SourceFiles/mtproto/session_private.cpp
index 6dc25c250..9ee0039a5 100644
--- a/Telegram/SourceFiles/mtproto/session_private.cpp
+++ b/Telegram/SourceFiles/mtproto/session_private.cpp
@@ -1033,8 +1033,6 @@ void SessionPrivate::onSentSome(uint64 size) {
 		}
 		if (isUploadDcId(_shiftedDcId)) {
 			remain *= kUploadSessionsCount;
-		} else if (isDownloadDcId(_shiftedDcId)) {
-			remain *= kDownloadSessionsCount;
 		}
 		_waitForReceivedTimer.callOnce(remain);
 	}
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index 9dbef1d25..0be8c9cfd 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -43,6 +43,9 @@ constexpr auto kMaxWebFileQueries = 8;
 // fixed part size download for hash checking.
 constexpr auto kPartSize = 128 * 1024;
 
+constexpr auto kStartSessionsCount = 1;
+constexpr auto kMaxSessionsCount = 8;
+
 } // namespace
 
 void DownloadManager::Queue::enqueue(not_null<Downloader*> loader) {
@@ -121,6 +124,7 @@ void DownloadManager::checkSendNext() {
 		const auto bestIndex = [&] {
 			const auto i = _requestedBytesAmount.find(dcId);
 			if (i == end(_requestedBytesAmount)) {
+				_requestedBytesAmount[dcId].resize(kStartSessionsCount);
 				return 0;
 			}
 			const auto j = ranges::min_element(i->second);
@@ -136,6 +140,9 @@ void DownloadManager::checkSendNext() {
 			loader->loadPart(bestIndex);
 		}
 	}
+	if (_requestedBytesAmount[0].empty()) {
+		_requestedBytesAmount[0] = std::vector<int>(1, 0);
+	}
 	if (_requestedBytesAmount[0][0] < kMaxWebFileQueries) {
 		if (const auto loader = _webLoaders.nextLoader()) {
 			loader->loadPart(0);
@@ -147,13 +154,14 @@ void DownloadManager::requestedAmountIncrement(
 		MTP::DcId dcId,
 		int index,
 		int amount) {
-	Expects(index >= 0 && index < MTP::kDownloadSessionsCount);
-
 	using namespace rpl::mappers;
 
 	auto it = _requestedBytesAmount.find(dcId);
 	if (it == _requestedBytesAmount.end()) {
-		it = _requestedBytesAmount.emplace(dcId, RequestedInDc { { 0 } }).first;
+		it = _requestedBytesAmount.emplace(
+			dcId,
+			std::vector<int>(dcId ? kStartSessionsCount : 1, 0)
+		).first;
 	}
 	it->second[index] += amount;
 	if (!dcId) {
@@ -163,6 +171,7 @@ void DownloadManager::requestedAmountIncrement(
 		killDownloadSessionsStop(dcId);
 	} else if (ranges::find_if(it->second, _1 > 0) == end(it->second)) {
 		killDownloadSessionsStart(dcId);
+		checkSendNext();
 	}
 }
 
@@ -197,8 +206,11 @@ void DownloadManager::killDownloadSessions() {
 	auto left = kKillSessionTimeout;
 	for (auto i = _killDownloadSessionTimes.begin(); i != _killDownloadSessionTimes.end(); ) {
 		if (i->second <= now) {
-			for (int j = 0; j < MTP::kDownloadSessionsCount; ++j) {
-				MTP::stopSession(MTP::downloadDcId(i->first, j));
+			const auto j = _requestedBytesAmount.find(i->first);
+			if (j != end(_requestedBytesAmount)) {
+				for (auto index = 0; index != int(j->second.size()); ++index) {
+					MTP::stopSession(MTP::downloadDcId(i->first, index));
+				}
 			}
 			i = _killDownloadSessionTimes.erase(i);
 		} else {
@@ -458,8 +470,6 @@ void FileLoader::cancel(bool fail) {
 	}
 	_data = QByteArray();
 
-	const auto downloader = _downloader;
-	const auto sessionGuard = &session();
 	const auto weak = QPointer<FileLoader>(this);
 	if (fail) {
 		emit failed(this, started);
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index c4702611a..73e7e7763 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -41,7 +41,7 @@ public:
 
 	[[nodiscard]] virtual MTP::DcId dcId() const = 0;
 	[[nodiscard]] virtual bool readyToRequest() const = 0;
-	[[nodiscard]] virtual void loadPart(int dcIndex) = 0;
+	virtual void loadPart(int dcIndex) = 0;
 
 };
 
@@ -91,8 +91,7 @@ private:
 
 	base::Observable<void> _taskFinishedObservable;
 
-	using RequestedInDc = std::array<int64, MTP::kDownloadSessionsCount>;
-	base::flat_map<MTP::DcId, RequestedInDc> _requestedBytesAmount;
+	base::flat_map<MTP::DcId, std::vector<int>> _requestedBytesAmount;
 
 	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
 	base::Timer _killDownloadSessionsTimer;

From f522cc94441145c06f0a9bff3bfc66ed1a3caedd Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 4 Dec 2019 10:42:55 +0300
Subject: [PATCH 86/91] Load streaming parts using Storage::DownloadManager.

---
 .../streaming/media_streaming_loader.cpp      |  4 ++
 .../media/streaming/media_streaming_loader.h  |  7 +--
 .../media_streaming_loader_mtproto.cpp        | 34 ++++++------
 .../media_streaming_loader_mtproto.h          | 14 ++---
 .../SourceFiles/storage/file_download.cpp     | 18 ++++---
 Telegram/SourceFiles/storage/file_download.h  |  3 +-
 .../storage/streamed_file_downloader.cpp      | 52 +++++++++++--------
 .../storage/streamed_file_downloader.h        |  2 +
 8 files changed, 82 insertions(+), 52 deletions(-)

diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader.cpp
index a84c6b39c..aaa79ffaa 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader.cpp
@@ -50,6 +50,10 @@ bool PriorityQueue::remove(int value) {
 	return true;
 }
 
+bool PriorityQueue::empty() const {
+	return _data.empty();
+}
+
 std::optional<int> PriorityQueue::front() const {
 	return _data.empty()
 		? std::nullopt
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader.h
index 51c486e7b..cfe19238e 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader.h
@@ -52,9 +52,10 @@ public:
 	bool add(int value);
 	bool remove(int value);
 	void increasePriority();
-	std::optional<int> front() const;
-	std::optional<int> take();
-	base::flat_set<int> takeInRange(int from, int till);
+	[[nodiscard]] bool empty() const;
+	[[nodiscard]] std::optional<int> front() const;
+	[[nodiscard]] std::optional<int> take();
+	[[nodiscard]] base::flat_set<int> takeInRange(int from, int till);
 	void clear();
 
 private:
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
index 6a713909b..13ac04549 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
@@ -37,6 +37,7 @@ LoaderMtproto::~LoaderMtproto() {
 	for (const auto [index, amount] : _amountByDcIndex) {
 		changeRequestedAmount(index, -amount);
 	}
+	_owner->remove(this);
 }
 
 std::optional<Storage::Cache::Key> LoaderMtproto::baseCacheKey() const {
@@ -60,7 +61,7 @@ void LoaderMtproto::load(int offset) {
 		if (_requests.contains(offset)) {
 			return;
 		} else if (_requested.add(offset)) {
-			sendNext();
+			_owner->enqueue(this); // #TODO download priority
 		}
 	});
 }
@@ -72,6 +73,7 @@ void LoaderMtproto::stop() {
 			_api.requestCanceller(),
 			&base::flat_map<int, mtpRequestId>::value_type::second);
 		_requested.clear();
+		_owner->remove(this);
 	});
 }
 
@@ -84,7 +86,7 @@ void LoaderMtproto::cancel(int offset) {
 void LoaderMtproto::cancelForOffset(int offset) {
 	if (const auto requestId = _requests.take(offset)) {
 		_api.request(*requestId).cancel();
-		sendNext();
+		_owner->enqueue(this);
 	} else {
 		_requested.remove(offset);
 	}
@@ -110,17 +112,21 @@ void LoaderMtproto::changeRequestedAmount(int index, int amount) {
 	_amountByDcIndex[index] += amount;
 }
 
-void LoaderMtproto::sendNext() {
-	if (_requests.size() >= kMaxConcurrentRequests) {
-		return;
-	}
+MTP::DcId LoaderMtproto::dcId() const {
+	return _dcId;
+}
+
+bool LoaderMtproto::readyToRequest() const {
+	return !_requested.empty();
+}
+
+void LoaderMtproto::loadPart(int dcIndex) {
 	const auto offset = _requested.take().value_or(-1);
 	if (offset < 0) {
 		return;
 	}
 
-	const auto index = _owner->chooseDcIndexForRequest(_dcId);
-	changeRequestedAmount(index, kPartSize);
+	changeRequestedAmount(dcIndex, kPartSize);
 
 	const auto usedFileReference = _location.fileReference();
 	const auto id = _api.request(MTPupload_GetFile(
@@ -129,23 +135,21 @@ void LoaderMtproto::sendNext() {
 		MTP_int(offset),
 		MTP_int(kPartSize)
 	)).done([=](const MTPupload_File &result) {
-		changeRequestedAmount(index, -kPartSize);
+		changeRequestedAmount(dcIndex, -kPartSize);
 		requestDone(offset, result);
 	}).fail([=](const RPCError &error) {
-		changeRequestedAmount(index, -kPartSize);
+		changeRequestedAmount(dcIndex, -kPartSize);
 		requestFailed(offset, error, usedFileReference);
 	}).toDC(
-		MTP::downloadDcId(_dcId, index)
+		MTP::downloadDcId(_dcId, dcIndex)
 	).send();
 	_requests.emplace(offset, id);
-
-	sendNext();
 }
 
 void LoaderMtproto::requestDone(int offset, const MTPupload_File &result) {
 	result.match([&](const MTPDupload_file &data) {
 		_requests.erase(offset);
-		sendNext();
+		_owner->enqueue(this);
 		_parts.fire({ offset, data.vbytes().v });
 	}, [&](const MTPDupload_fileCdnRedirect &data) {
 		changeCdnParams(
@@ -189,7 +193,7 @@ void LoaderMtproto::requestFailed(
 			return;
 		} else {
 			_requested.add(offset);
-			sendNext();
+			_owner->enqueue(this);
 		}
 	};
 	_owner->api().refreshFileReference(
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
index a7f16f4f8..a9a229403 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
@@ -10,15 +10,15 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "media/streaming/media_streaming_loader.h"
 #include "mtproto/sender.h"
 #include "data/data_file_origin.h"
-
-namespace Storage {
-class DownloadManager;
-} // namespace Storage
+#include "storage/file_download.h"
 
 namespace Media {
 namespace Streaming {
 
-class LoaderMtproto : public Loader, public base::has_weak_ptr {
+class LoaderMtproto
+	: public Loader
+	, public base::has_weak_ptr
+	, public Storage::Downloader {
 public:
 	LoaderMtproto(
 		not_null<Storage::DownloadManager*> owner,
@@ -44,7 +44,9 @@ public:
 	void clearAttachedDownloader() override;
 
 private:
-	void sendNext();
+	MTP::DcId dcId() const override;
+	bool readyToRequest() const override;
+	void loadPart(int dcIndex) override;
 
 	void requestDone(int offset, const MTPupload_File &result);
 	void requestFailed(
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index 0be8c9cfd..ec759ef4d 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -45,6 +45,7 @@ constexpr auto kPartSize = 128 * 1024;
 
 constexpr auto kStartSessionsCount = 1;
 constexpr auto kMaxSessionsCount = 8;
+constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
 
 } // namespace
 
@@ -78,6 +79,10 @@ void DownloadManager::Queue::resetGeneration() {
 	std::swap(_loaders, _previousGeneration);
 }
 
+bool DownloadManager::Queue::empty() const {
+	return _loaders.empty() && _previousGeneration.empty();
+}
+
 Downloader *DownloadManager::Queue::nextLoader() const {
 	auto &&all = ranges::view::concat(_loaders, _previousGeneration);
 	const auto i = ranges::find(all, true, &FileLoader::readyToRequest);
@@ -86,6 +91,7 @@ Downloader *DownloadManager::Queue::nextLoader() const {
 
 DownloadManager::DownloadManager(not_null<ApiWrap*> api)
 : _api(api)
+, _resetGenerationTimer([=] { resetGeneration(); })
 , _killDownloadSessionsTimer([=] { killDownloadSessions(); }) {
 }
 
@@ -96,11 +102,8 @@ DownloadManager::~DownloadManager() {
 void DownloadManager::enqueue(not_null<Downloader*> loader) {
 	const auto dcId = loader->dcId();
 	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).enqueue(loader);
-	if (!_resettingGeneration) {
-		_resettingGeneration = true;
-		crl::on_main(this, [=] {
-			resetGeneration();
-		});
+	if (!_resetGenerationTimer.isActive()) {
+		_resetGenerationTimer.callOnce(kResetDownloadPrioritiesTimeout);
 	}
 	checkSendNext();
 }
@@ -112,7 +115,7 @@ void DownloadManager::remove(not_null<Downloader*> loader) {
 }
 
 void DownloadManager::resetGeneration() {
-	_resettingGeneration = false;
+	_resetGenerationTimer.cancel();
 	for (auto &[dcId, queue] : _mtprotoLoaders) {
 		queue.resetGeneration();
 	}
@@ -121,6 +124,9 @@ void DownloadManager::resetGeneration() {
 
 void DownloadManager::checkSendNext() {
 	for (auto &[dcId, queue] : _mtprotoLoaders) {
+		if (queue.empty()) {
+			continue;
+		}
 		const auto bestIndex = [&] {
 			const auto i = _requestedBytesAmount.find(dcId);
 			if (i == end(_requestedBytesAmount)) {
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index 73e7e7763..520501de9 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -71,6 +71,7 @@ private:
 		void enqueue(not_null<Downloader*> loader);
 		void remove(not_null<Downloader*> loader);
 		void resetGeneration();
+		[[nodiscard]] bool empty() const;
 		[[nodiscard]] Downloader *nextLoader() const;
 
 	private:
@@ -92,13 +93,13 @@ private:
 	base::Observable<void> _taskFinishedObservable;
 
 	base::flat_map<MTP::DcId, std::vector<int>> _requestedBytesAmount;
+	base::Timer _resetGenerationTimer;
 
 	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
 	base::Timer _killDownloadSessionsTimer;
 
 	base::flat_map<MTP::DcId, Queue> _mtprotoLoaders;
 	Queue _webLoaders;
-	bool _resettingGeneration = false;
 
 };
 
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
index aaab67bfa..33b15bb54 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
@@ -16,6 +16,7 @@ namespace {
 using namespace Media::Streaming;
 
 constexpr auto kPartSize = Loader::kPartSize;
+constexpr auto kRequestPartsCount = 8;
 
 } // namespace
 
@@ -60,6 +61,8 @@ StreamedFileDownloader::StreamedFileDownloader(
 			savePart(std::move(part));
 		}
 	}, _lifetime);
+
+	requestParts();
 }
 
 StreamedFileDownloader::~StreamedFileDownloader() {
@@ -78,6 +81,31 @@ void StreamedFileDownloader::stop() {
 	cancelRequests();
 }
 
+void StreamedFileDownloader::requestParts() {
+	while (!_finished
+		&& _nextPartIndex < _partsCount
+		&& _partsRequested < kRequestPartsCount) {
+		requestPart();
+	}
+}
+
+void StreamedFileDownloader::requestPart() {
+	Expects(!_finished);
+
+	const auto index = std::find(
+		begin(_partIsSaved) + _nextPartIndex,
+		end(_partIsSaved),
+		false
+	) - begin(_partIsSaved);
+	if (index == _partsCount) {
+		_nextPartIndex = _partsCount;
+		return;
+	}
+	_nextPartIndex = index + 1;
+	_reader->loadForDownloader(this, index * kPartSize);
+	++_partsRequested;
+}
+
 QByteArray StreamedFileDownloader::readLoadedPart(int offset) {
 	Expects(offset >= 0 && offset < _size);
 	Expects(!(offset % kPartSize));
@@ -104,30 +132,11 @@ void StreamedFileDownloader::cancelRequests() {
 }
 
 bool StreamedFileDownloader::readyToRequest() const {
-	if (_finished || _nextPartIndex >= _partsCount) {
-		return false;
-	}
-	_nextPartIndex = std::find(
-		begin(_partIsSaved) + _nextPartIndex,
-		end(_partIsSaved),
-		false
-	) - begin(_partIsSaved);
-	return (_nextPartIndex < _partsCount);
+	return false;
 }
 
 void StreamedFileDownloader::loadPart(int dcIndex) {
-	const auto index = std::find(
-		begin(_partIsSaved) + _nextPartIndex,
-		end(_partIsSaved),
-		false
-	) - begin(_partIsSaved);
-	if (index == _partsCount) {
-		_nextPartIndex = _partsCount;
-		return;
-	}
-	_nextPartIndex = index + 1;
-	_reader->loadForDownloader(this, index * kPartSize);
-	++_partsRequested;
+	Unexpected("StreamedFileDownloader can't load parts.");
 }
 
 void StreamedFileDownloader::savePart(const LoadedPart &part) {
@@ -159,6 +168,7 @@ void StreamedFileDownloader::savePart(const LoadedPart &part) {
 		}
 	}
 	_reader->doneForDownloader(offset);
+	requestParts();
 	notifyAboutProgress();
 }
 
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.h b/Telegram/SourceFiles/storage/streamed_file_downloader.h
index 803bc3cde..90aea8c09 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.h
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.h
@@ -51,6 +51,8 @@ private:
 	void cancelRequests() override;
 	bool readyToRequest() const override;
 	void loadPart(int dcIndex) override;
+	void requestParts();
+	void requestPart();
 
 	void savePart(const Media::Streaming::LoadedPart &part);
 

From 4611727ab9006f1be4a3acb95567e1d5aeeccb1b Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Wed, 4 Dec 2019 15:15:58 +0300
Subject: [PATCH 87/91] Rewrite webFileLoader without Storage::DownloadManager.

---
 Telegram/SourceFiles/apiwrap.cpp              |    2 +-
 Telegram/SourceFiles/core/application.cpp     |    1 -
 Telegram/SourceFiles/data/data_document.cpp   |    2 +
 .../passport/passport_form_controller.cpp     |    2 +-
 .../SourceFiles/storage/file_download.cpp     | 1050 +----------------
 Telegram/SourceFiles/storage/file_download.h  |  253 +---
 .../storage/file_download_mtproto.cpp         |  590 +++++++++
 .../storage/file_download_mtproto.h           |  140 +++
 .../SourceFiles/storage/file_download_web.cpp |  527 +++++++++
 .../SourceFiles/storage/file_download_web.h   |   45 +
 .../storage/streamed_file_downloader.cpp      |   11 +-
 .../storage/streamed_file_downloader.h        |    3 +-
 .../SourceFiles/ui/image/image_source.cpp     |    5 +-
 Telegram/gyp/telegram/sources.txt             |    4 +
 14 files changed, 1334 insertions(+), 1301 deletions(-)
 create mode 100644 Telegram/SourceFiles/storage/file_download_mtproto.cpp
 create mode 100644 Telegram/SourceFiles/storage/file_download_mtproto.h
 create mode 100644 Telegram/SourceFiles/storage/file_download_web.cpp
 create mode 100644 Telegram/SourceFiles/storage/file_download_web.h

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index 9cb0a8f54..b9272d3ec 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -55,7 +55,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/emoji_config.h"
 #include "support/support_helper.h"
 #include "storage/localimageloader.h"
-#include "storage/file_download.h"
+#include "storage/file_download_mtproto.h"
 #include "storage/file_upload.h"
 #include "storage/storage_facade.h"
 #include "storage/storage_shared_media.h"
diff --git a/Telegram/SourceFiles/core/application.cpp b/Telegram/SourceFiles/core/application.cpp
index 9954a1faa..c13abe1d2 100644
--- a/Telegram/SourceFiles/core/application.cpp
+++ b/Telegram/SourceFiles/core/application.cpp
@@ -139,7 +139,6 @@ Application::~Application() {
 	Ui::Emoji::Clear();
 	Media::Clip::Finish();
 
-	stopWebLoadManager();
 	App::deinitMedia();
 
 	Window::Theme::Uninitialize();
diff --git a/Telegram/SourceFiles/data/data_document.cpp b/Telegram/SourceFiles/data/data_document.cpp
index f23a484b0..f00a70b80 100644
--- a/Telegram/SourceFiles/data/data_document.cpp
+++ b/Telegram/SourceFiles/data/data_document.cpp
@@ -21,6 +21,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "media/streaming/media_streaming_loader_local.h"
 #include "storage/localstorage.h"
 #include "storage/streamed_file_downloader.h"
+#include "storage/file_download_mtproto.h"
+#include "storage/file_download_web.h"
 #include "platform/platform_specific.h"
 #include "history/history.h"
 #include "history/history_item.h"
diff --git a/Telegram/SourceFiles/passport/passport_form_controller.cpp b/Telegram/SourceFiles/passport/passport_form_controller.cpp
index 6d4e2c0fb..05b3c88b1 100644
--- a/Telegram/SourceFiles/passport/passport_form_controller.cpp
+++ b/Telegram/SourceFiles/passport/passport_form_controller.cpp
@@ -28,7 +28,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "storage/localimageloader.h"
 #include "storage/localstorage.h"
 #include "storage/file_upload.h"
-#include "storage/file_download.h"
+#include "storage/file_download_mtproto.h"
 #include "app.h"
 #include "apiwrap.h"
 
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index ec759ef4d..77f6f951a 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -37,12 +37,6 @@ constexpr auto kMaxWaitedInConnection = 512 * 1024;
 // Max 8 http[s] files downloaded at the same time.
 constexpr auto kMaxWebFileQueries = 8;
 
-// Different part sizes are not supported for now :(
-// Because we start downloading with some part size
-// and then we get a cdn-redirect where we support only
-// fixed part size download for hash checking.
-constexpr auto kPartSize = 128 * 1024;
-
 constexpr auto kStartSessionsCount = 1;
 constexpr auto kMaxSessionsCount = 8;
 constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
@@ -85,7 +79,7 @@ bool DownloadManager::Queue::empty() const {
 
 Downloader *DownloadManager::Queue::nextLoader() const {
 	auto &&all = ranges::view::concat(_loaders, _previousGeneration);
-	const auto i = ranges::find(all, true, &FileLoader::readyToRequest);
+	const auto i = ranges::find(all, true, &Downloader::readyToRequest);
 	return (i != all.end()) ? i->get() : nullptr;
 }
 
@@ -134,8 +128,8 @@ void DownloadManager::checkSendNext() {
 				return 0;
 			}
 			const auto j = ranges::min_element(i->second);
-			const auto inConnection = *j;
-			return (inConnection + kPartSize <= kMaxWaitedInConnection)
+			const auto already = *j;
+			return (already + kDownloadPartSize <= kMaxWaitedInConnection)
 				? (j - begin(i->second))
 				: -1;
 		}();
@@ -233,28 +227,15 @@ void DownloadManager::killDownloadSessions() {
 
 } // namespace Storage
 
-namespace {
-
-QThread *_webLoadThread = nullptr;
-WebLoadManager *_webLoadManager = nullptr;
-WebLoadManager *webLoadManager() {
-	return (_webLoadManager && _webLoadManager != FinishedWebLoadManager) ? _webLoadManager : nullptr;
-}
-WebLoadMainManager *_webLoadMainManager = nullptr;
-
-} // namespace
-
 FileLoader::FileLoader(
 	const QString &toFile,
-	MTP::DcId dcId,
 	int32 size,
 	LocationType locationType,
 	LoadToCacheSetting toCache,
 	LoadFromCloudSetting fromCloud,
 	bool autoLoading,
 	uint8 cacheTag)
-: _dcId(dcId)
-, _downloader(&Auth().downloader())
+: _session(&Auth())
 , _autoLoading(autoLoading)
 , _cacheTag(cacheTag)
 , _filename(toFile)
@@ -266,12 +247,10 @@ FileLoader::FileLoader(
 	Expects(!_filename.isEmpty() || (_size <= Storage::kMaxFileInMemory));
 }
 
-FileLoader::~FileLoader() {
-	_downloader->remove(this);
-}
+FileLoader::~FileLoader() = default;
 
 Main::Session &FileLoader::session() const {
-	return _downloader->api().session();
+	return *_session;
 }
 
 void FileLoader::finishWithBytes(const QByteArray &data) {
@@ -297,7 +276,7 @@ void FileLoader::finishWithBytes(const QByteArray &data) {
 		Platform::File::PostprocessDownloaded(
 			QFileInfo(_file).absoluteFilePath());
 	}
-	_downloader->taskFinished().notify();
+	Auth().downloaderTaskFinished().notify();
 }
 
 QByteArray FileLoader::imageFormat(const QSize &shrinkBox) const {
@@ -390,7 +369,7 @@ void FileLoader::start() {
 			return cancel(true);
 		}
 	}
-	_downloader->enqueue(this);
+	startLoading();
 }
 
 void FileLoader::loadLocal(const Storage::Cache::Key &key) {
@@ -576,8 +555,6 @@ bool FileLoader::finalizeResult() {
 		Platform::File::PostprocessDownloaded(
 			QFileInfo(_file).absoluteFilePath());
 	}
-	_downloader->remove(this);
-
 	if (_localStatus == LocalStatus::NotFound) {
 		if (const auto key = fileLocationKey()) {
 			if (!_filename.isEmpty()) {
@@ -593,1015 +570,6 @@ bool FileLoader::finalizeResult() {
 					_cacheTag));
 		}
 	}
-	_downloader->taskFinished().notify();
+	Auth().downloaderTaskFinished().notify();
 	return true;
 }
-
-mtpFileLoader::mtpFileLoader(
-	const StorageFileLocation &location,
-	Data::FileOrigin origin,
-	LocationType type,
-	const QString &to,
-	int32 size,
-	LoadToCacheSetting toCache,
-	LoadFromCloudSetting fromCloud,
-	bool autoLoading,
-	uint8 cacheTag)
-: FileLoader(
-	to,
-	location.dcId(),
-	size,
-	type,
-	toCache,
-	fromCloud,
-	autoLoading,
-	cacheTag)
-, _location(location)
-, _origin(origin) {
-}
-
-mtpFileLoader::mtpFileLoader(
-	const WebFileLocation &location,
-	int32 size,
-	LoadFromCloudSetting fromCloud,
-	bool autoLoading,
-	uint8 cacheTag)
-: FileLoader(
-	QString(),
-	Global::WebFileDcId(),
-	size,
-	UnknownFileLocation,
-	LoadToCacheAsWell,
-	fromCloud,
-	autoLoading,
-	cacheTag)
-, _location(location) {
-}
-
-mtpFileLoader::mtpFileLoader(
-	const GeoPointLocation &location,
-	int32 size,
-	LoadFromCloudSetting fromCloud,
-	bool autoLoading,
-	uint8 cacheTag)
-: FileLoader(
-	QString(),
-	Global::WebFileDcId(),
-	size,
-	UnknownFileLocation,
-	LoadToCacheAsWell,
-	fromCloud,
-	autoLoading,
-	cacheTag)
-, _location(location) {
-}
-
-mtpFileLoader::~mtpFileLoader() {
-	cancelRequests();
-}
-
-Data::FileOrigin mtpFileLoader::fileOrigin() const {
-	return _origin;
-}
-
-uint64 mtpFileLoader::objId() const {
-	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
-		return storage->objectId();
-	}
-	return 0;
-}
-
-void mtpFileLoader::refreshFileReferenceFrom(
-		const Data::UpdatedFileReferences &updates,
-		int requestId,
-		const QByteArray &current) {
-	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
-		storage->refreshFileReference(updates);
-		if (storage->fileReference() == current) {
-			cancel(true);
-			return;
-		}
-	} else {
-		cancel(true);
-		return;
-	}
-	makeRequest(finishSentRequest(requestId));
-}
-
-bool mtpFileLoader::readyToRequest() const {
-	return !_finished
-		&& !_lastComplete
-		&& (_sentRequests.empty() || _size != 0)
-		&& (!_size || _nextRequestOffset < _size);
-}
-
-void mtpFileLoader::loadPart(int dcIndex) {
-	Expects(readyToRequest());
-
-	makeRequest({ _nextRequestOffset, dcIndex });
-	_nextRequestOffset += Storage::kPartSize;
-}
-
-mtpRequestId mtpFileLoader::sendRequest(const RequestData &requestData) {
-	const auto offset = requestData.offset;
-	const auto limit = Storage::kPartSize;
-	const auto shiftedDcId = MTP::downloadDcId(
-		_cdnDcId ? _cdnDcId : dcId(),
-		requestData.dcIndex);
-	if (_cdnDcId) {
-		return MTP::send(
-			MTPupload_GetCdnFile(
-				MTP_bytes(_cdnToken),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::cdnPartLoaded),
-			rpcFail(&mtpFileLoader::cdnPartFailed),
-			shiftedDcId,
-			50);
-	}
-	return _location.match([&](const WebFileLocation &location) {
-		return MTP::send(
-			MTPupload_GetWebFile(
-				MTP_inputWebFileLocation(
-					MTP_bytes(location.url()),
-					MTP_long(location.accessHash())),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::webPartLoaded),
-			rpcFail(&mtpFileLoader::partFailed),
-			shiftedDcId,
-			50);
-	}, [&](const GeoPointLocation &location) {
-		return MTP::send(
-			MTPupload_GetWebFile(
-				MTP_inputWebFileGeoPointLocation(
-					MTP_inputGeoPoint(
-						MTP_double(location.lat),
-						MTP_double(location.lon)),
-					MTP_long(location.access),
-					MTP_int(location.width),
-					MTP_int(location.height),
-					MTP_int(location.zoom),
-					MTP_int(location.scale)),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::webPartLoaded),
-			rpcFail(&mtpFileLoader::partFailed),
-			shiftedDcId,
-			50);
-	}, [&](const StorageFileLocation &location) {
-		return MTP::send(
-			MTPupload_GetFile(
-				MTP_flags(0),
-				location.tl(session().userId()),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::normalPartLoaded),
-			rpcFail(
-				&mtpFileLoader::normalPartFailed,
-				location.fileReference()),
-			shiftedDcId,
-			50);
-	});
-}
-
-void mtpFileLoader::makeRequest(const RequestData &requestData) {
-	Expects(!_finished);
-
-	placeSentRequest(sendRequest(requestData), requestData);
-}
-
-void mtpFileLoader::requestMoreCdnFileHashes() {
-	Expects(!_finished);
-
-	if (_cdnHashesRequestId || _cdnUncheckedParts.empty()) {
-		return;
-	}
-
-	const auto requestData = _cdnUncheckedParts.cbegin()->first;
-	const auto shiftedDcId = MTP::downloadDcId(
-		dcId(),
-		requestData.dcIndex);
-	const auto requestId = _cdnHashesRequestId = MTP::send(
-		MTPupload_GetCdnFileHashes(
-			MTP_bytes(_cdnToken),
-			MTP_int(requestData.offset)),
-		rpcDone(&mtpFileLoader::getCdnFileHashesDone),
-		rpcFail(&mtpFileLoader::cdnPartFailed),
-		shiftedDcId);
-	placeSentRequest(requestId, requestData);
-}
-
-void mtpFileLoader::normalPartLoaded(
-		const MTPupload_File &result,
-		mtpRequestId requestId) {
-	Expects(!_finished);
-
-	const auto requestData = finishSentRequest(requestId);
-	result.match([&](const MTPDupload_fileCdnRedirect &data) {
-		switchToCDN(requestData, data);
-	}, [&](const MTPDupload_file &data) {
-		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
-	});
-}
-
-void mtpFileLoader::webPartLoaded(
-		const MTPupload_WebFile &result,
-		mtpRequestId requestId) {
-	result.match([&](const MTPDupload_webFile &data) {
-		const auto requestData = finishSentRequest(requestId);
-		if (!_size) {
-			_size = data.vsize().v;
-		} else if (data.vsize().v != _size) {
-			LOG(("MTP Error: "
-				"Bad size provided by bot for webDocument: %1, real: %2"
-				).arg(_size
-				).arg(data.vsize().v));
-			cancel(true);
-			return;
-		}
-		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
-	});
-}
-
-void mtpFileLoader::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId) {
-	Expects(!_finished);
-
-	const auto requestData = finishSentRequest(requestId);
-	result.match([&](const MTPDupload_cdnFileReuploadNeeded &data) {
-		const auto shiftedDcId = MTP::downloadDcId(
-			dcId(),
-			requestData.dcIndex);
-		const auto requestId = MTP::send(
-			MTPupload_ReuploadCdnFile(
-				MTP_bytes(_cdnToken),
-				data.vrequest_token()),
-			rpcDone(&mtpFileLoader::reuploadDone),
-			rpcFail(&mtpFileLoader::cdnPartFailed),
-			shiftedDcId);
-		placeSentRequest(requestId, requestData);
-	}, [&](const MTPDupload_cdnFile &data) {
-		auto key = bytes::make_span(_cdnEncryptionKey);
-		auto iv = bytes::make_span(_cdnEncryptionIV);
-		Expects(key.size() == MTP::CTRState::KeySize);
-		Expects(iv.size() == MTP::CTRState::IvecSize);
-
-		auto state = MTP::CTRState();
-		auto ivec = bytes::make_span(state.ivec);
-		std::copy(iv.begin(), iv.end(), ivec.begin());
-
-		auto counterOffset = static_cast<uint32>(requestData.offset) >> 4;
-		state.ivec[15] = static_cast<uchar>(counterOffset & 0xFF);
-		state.ivec[14] = static_cast<uchar>((counterOffset >> 8) & 0xFF);
-		state.ivec[13] = static_cast<uchar>((counterOffset >> 16) & 0xFF);
-		state.ivec[12] = static_cast<uchar>((counterOffset >> 24) & 0xFF);
-
-		auto decryptInPlace = data.vbytes().v;
-		auto buffer = bytes::make_detached_span(decryptInPlace);
-		MTP::aesCtrEncrypt(buffer, key.data(), &state);
-
-		switch (checkCdnFileHash(requestData.offset, buffer)) {
-		case CheckCdnHashResult::NoHash: {
-			_cdnUncheckedParts.emplace(requestData, decryptInPlace);
-			requestMoreCdnFileHashes();
-		} return;
-
-		case CheckCdnHashResult::Invalid: {
-			LOG(("API Error: Wrong cdnFileHash for offset %1."
-				).arg(requestData.offset));
-			cancel(true);
-		} return;
-
-		case CheckCdnHashResult::Good: {
-			partLoaded(requestData.offset, buffer);
-		} return;
-		}
-		Unexpected("Result of checkCdnFileHash()");
-	});
-}
-
-mtpFileLoader::CheckCdnHashResult mtpFileLoader::checkCdnFileHash(
-		int offset,
-		bytes::const_span buffer) {
-	const auto cdnFileHashIt = _cdnFileHashes.find(offset);
-	if (cdnFileHashIt == _cdnFileHashes.cend()) {
-		return CheckCdnHashResult::NoHash;
-	}
-	const auto realHash = openssl::Sha256(buffer);
-	const auto receivedHash = bytes::make_span(cdnFileHashIt->second.hash);
-	if (bytes::compare(realHash, receivedHash)) {
-		return CheckCdnHashResult::Invalid;
-	}
-	return CheckCdnHashResult::Good;
-}
-
-void mtpFileLoader::reuploadDone(
-		const MTPVector<MTPFileHash> &result,
-		mtpRequestId requestId) {
-	const auto requestData = finishSentRequest(requestId);
-	addCdnHashes(result.v);
-	makeRequest(requestData);
-}
-
-void mtpFileLoader::getCdnFileHashesDone(
-		const MTPVector<MTPFileHash> &result,
-		mtpRequestId requestId) {
-	Expects(!_finished);
-	Expects(_cdnHashesRequestId == requestId);
-
-	_cdnHashesRequestId = 0;
-
-	const auto requestData = finishSentRequest(requestId);
-	addCdnHashes(result.v);
-	auto someMoreChecked = false;
-	for (auto i = _cdnUncheckedParts.begin(); i != _cdnUncheckedParts.cend();) {
-		const auto uncheckedData = i->first;
-		const auto uncheckedBytes = bytes::make_span(i->second);
-
-		switch (checkCdnFileHash(uncheckedData.offset, uncheckedBytes)) {
-		case CheckCdnHashResult::NoHash: {
-			++i;
-		} break;
-
-		case CheckCdnHashResult::Invalid: {
-			LOG(("API Error: Wrong cdnFileHash for offset %1."
-				).arg(uncheckedData.offset));
-			cancel(true);
-			return;
-		} break;
-
-		case CheckCdnHashResult::Good: {
-			someMoreChecked = true;
-			const auto goodOffset = uncheckedData.offset;
-			const auto goodBytes = std::move(i->second);
-			const auto weak = QPointer<mtpFileLoader>(this);
-			i = _cdnUncheckedParts.erase(i);
-			if (!feedPart(goodOffset, bytes::make_span(goodBytes))
-				|| !weak) {
-				return;
-			} else if (_finished) {
-				notifyAboutProgress();
-				return;
-			}
-		} break;
-
-		default: Unexpected("Result of checkCdnFileHash()");
-		}
-	}
-	if (someMoreChecked) {
-		const auto weak = QPointer<mtpFileLoader>(this);
-		notifyAboutProgress();
-		if (weak) {
-			requestMoreCdnFileHashes();
-		}
-		return;
-	}
-	LOG(("API Error: "
-		"Could not find cdnFileHash for offset %1 "
-		"after getCdnFileHashes request."
-		).arg(requestData.offset));
-	cancel(true);
-}
-
-void mtpFileLoader::placeSentRequest(
-		mtpRequestId requestId,
-		const RequestData &requestData) {
-	Expects(!_finished);
-
-	_downloader->requestedAmountIncrement(
-		dcId(),
-		requestData.dcIndex,
-		Storage::kPartSize);
-	_sentRequests.emplace(requestId, requestData);
-}
-
-auto mtpFileLoader::finishSentRequest(mtpRequestId requestId)
--> RequestData {
-	auto it = _sentRequests.find(requestId);
-	Assert(it != _sentRequests.cend());
-
-	const auto result = it->second;
-	_downloader->requestedAmountIncrement(
-		dcId(),
-		result.dcIndex,
-		-Storage::kPartSize);
-	_sentRequests.erase(it);
-
-	return result;
-}
-
-bool mtpFileLoader::feedPart(int offset, bytes::const_span buffer) {
-	if (!writeResultPart(offset, buffer)) {
-		return false;
-	}
-	if (buffer.empty() || (buffer.size() % 1024)) { // bad next offset
-		_lastComplete = true;
-	}
-	const auto finished = _sentRequests.empty()
-		&& _cdnUncheckedParts.empty()
-		&& (_lastComplete || (_size && _nextRequestOffset >= _size));
-	if (finished && !finalizeResult()) {
-		return false;
-	}
-	return true;
-}
-
-void mtpFileLoader::partLoaded(int offset, bytes::const_span buffer) {
-	if (feedPart(offset, buffer)) {
-		notifyAboutProgress();
-	}
-}
-
-bool mtpFileLoader::normalPartFailed(
-		QByteArray fileReference,
-		const RPCError &error,
-		mtpRequestId requestId) {
-	if (MTP::isDefaultHandledError(error)) {
-		return false;
-	}
-	if (error.code() == 400
-		&& error.type().startsWith(qstr("FILE_REFERENCE_"))) {
-		session().api().refreshFileReference(
-			_origin,
-			this,
-			requestId,
-			fileReference);
-		return true;
-	}
-	return partFailed(error, requestId);
-}
-
-
-bool mtpFileLoader::partFailed(
-		const RPCError &error,
-		mtpRequestId requestId) {
-	if (MTP::isDefaultHandledError(error)) {
-		return false;
-	}
-	cancel(true);
-	return true;
-}
-
-bool mtpFileLoader::cdnPartFailed(
-		const RPCError &error,
-		mtpRequestId requestId) {
-	if (MTP::isDefaultHandledError(error)) {
-		return false;
-	}
-
-	if (requestId == _cdnHashesRequestId) {
-		_cdnHashesRequestId = 0;
-	}
-	if (error.type() == qstr("FILE_TOKEN_INVALID")
-		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
-		const auto requestData = finishSentRequest(requestId);
-		changeCDNParams(
-			requestData,
-			0,
-			QByteArray(),
-			QByteArray(),
-			QByteArray(),
-			QVector<MTPFileHash>());
-		return true;
-	}
-	return partFailed(error, requestId);
-}
-
-void mtpFileLoader::cancelRequests() {
-	while (!_sentRequests.empty()) {
-		auto requestId = _sentRequests.begin()->first;
-		MTP::cancel(requestId);
-		[[maybe_unused]] const auto data = finishSentRequest(requestId);
-	}
-}
-
-void mtpFileLoader::switchToCDN(
-		const RequestData &requestData,
-		const MTPDupload_fileCdnRedirect &redirect) {
-	changeCDNParams(
-		requestData,
-		redirect.vdc_id().v,
-		redirect.vfile_token().v,
-		redirect.vencryption_key().v,
-		redirect.vencryption_iv().v,
-		redirect.vfile_hashes().v);
-}
-
-void mtpFileLoader::addCdnHashes(const QVector<MTPFileHash> &hashes) {
-	for (const auto &hash : hashes) {
-		hash.match([&](const MTPDfileHash &data) {
-			_cdnFileHashes.emplace(
-				data.voffset().v,
-				CdnFileHash{ data.vlimit().v, data.vhash().v });
-		});
-	}
-}
-
-void mtpFileLoader::changeCDNParams(
-		const RequestData &requestData,
-		MTP::DcId dcId,
-		const QByteArray &token,
-		const QByteArray &encryptionKey,
-		const QByteArray &encryptionIV,
-		const QVector<MTPFileHash> &hashes) {
-	if (dcId != 0
-		&& (encryptionKey.size() != MTP::CTRState::KeySize
-			|| encryptionIV.size() != MTP::CTRState::IvecSize)) {
-		LOG(("Message Error: Wrong key (%1) / iv (%2) size in CDN params").arg(encryptionKey.size()).arg(encryptionIV.size()));
-		cancel(true);
-		return;
-	}
-
-	auto resendAllRequests = (_cdnDcId != dcId
-		|| _cdnToken != token
-		|| _cdnEncryptionKey != encryptionKey
-		|| _cdnEncryptionIV != encryptionIV);
-	_cdnDcId = dcId;
-	_cdnToken = token;
-	_cdnEncryptionKey = encryptionKey;
-	_cdnEncryptionIV = encryptionIV;
-	addCdnHashes(hashes);
-
-	if (resendAllRequests && !_sentRequests.empty()) {
-		auto resendRequests = std::vector<RequestData>();
-		resendRequests.reserve(_sentRequests.size());
-		while (!_sentRequests.empty()) {
-			auto requestId = _sentRequests.begin()->first;
-			MTP::cancel(requestId);
-			resendRequests.push_back(finishSentRequest(requestId));
-		}
-		for (const auto &requestData : resendRequests) {
-			makeRequest(requestData);
-		}
-	}
-	makeRequest(requestData);
-}
-
-Storage::Cache::Key mtpFileLoader::cacheKey() const {
-	return _location.match([&](const WebFileLocation &location) {
-		return Data::WebDocumentCacheKey(location);
-	}, [&](const GeoPointLocation &location) {
-		return Data::GeoPointCacheKey(location);
-	}, [&](const StorageFileLocation &location) {
-		return location.cacheKey();
-	});
-}
-
-std::optional<MediaKey> mtpFileLoader::fileLocationKey() const {
-	if (_locationType != UnknownFileLocation) {
-		return mediaKey(_locationType, dcId(), objId());
-	}
-	return std::nullopt;
-}
-
-webFileLoader::webFileLoader(
-	const QString &url,
-	const QString &to,
-	LoadFromCloudSetting fromCloud,
-	bool autoLoading,
-	uint8 cacheTag)
-: FileLoader(
-	QString(),
-	0,
-	0,
-	UnknownFileLocation,
-	LoadToCacheAsWell,
-	fromCloud,
-	autoLoading,
-	cacheTag)
-, _url(url) {
-}
-
-webFileLoader::~webFileLoader() {
-	markAsNotSent();
-}
-
-bool webFileLoader::readyToRequest() const {
-	return !_finished
-		&& !_requestSent
-		&& (_webLoadManager != FinishedWebLoadManager);
-}
-
-void webFileLoader::loadPart(int dcIndex) {
-	Expects(readyToRequest());
-
-	if (!_webLoadManager) {
-		_webLoadMainManager = new WebLoadMainManager();
-
-		_webLoadThread = new QThread();
-		_webLoadManager = new WebLoadManager(_webLoadThread);
-
-		_webLoadThread->start();
-	}
-
-	markAsSent();
-	_webLoadManager->append(this, _url);
-}
-
-int webFileLoader::currentOffset() const {
-	return _already;
-}
-
-void webFileLoader::loadProgress(qint64 already, qint64 size) {
-	_size = size;
-	_already = already;
-	notifyAboutProgress();
-}
-
-void webFileLoader::loadFinished(const QByteArray &data) {
-	markAsNotSent();
-	if (writeResultPart(0, bytes::make_span(data))) {
-		if (finalizeResult()) {
-			notifyAboutProgress();
-		}
-	}
-}
-
-void webFileLoader::loadError() {
-	markAsNotSent();
-	cancel(true);
-}
-
-Storage::Cache::Key webFileLoader::cacheKey() const {
-	return Data::UrlCacheKey(_url);
-}
-
-std::optional<MediaKey> webFileLoader::fileLocationKey() const {
-	return std::nullopt;
-}
-
-void webFileLoader::cancelRequests() {
-	if (!webLoadManager()) {
-		return;
-	}
-	webLoadManager()->stop(this);
-	markAsNotSent();
-}
-
-void webFileLoader::markAsSent() {
-	if (_requestSent) {
-		return;
-	}
-	_requestSent = true;
-	_downloader->requestedAmountIncrement(0, 0, 1);
-}
-
-void webFileLoader::markAsNotSent() {
-	if (!_requestSent) {
-		return;
-	}
-	_requestSent = false;
-	_downloader->requestedAmountIncrement(0, 0, -1);
-}
-
-class webFileLoaderPrivate {
-public:
-	webFileLoaderPrivate(webFileLoader *loader, const QString &url)
-		: _interface(loader)
-		, _url(url)
-		, _redirectsLeft(kMaxHttpRedirects) {
-	}
-
-	QNetworkReply *reply() {
-		return _reply;
-	}
-
-	QNetworkReply *request(QNetworkAccessManager &manager, const QString &redirect) {
-		if (!redirect.isEmpty()) _url = redirect;
-
-		QNetworkRequest req(_url);
-		QByteArray rangeHeaderValue = "bytes=" + QByteArray::number(_already) + "-";
-		req.setRawHeader("Range", rangeHeaderValue);
-		_reply = manager.get(req);
-		return _reply;
-	}
-
-	bool oneMoreRedirect() {
-		if (_redirectsLeft) {
-			--_redirectsLeft;
-			return true;
-		}
-		return false;
-	}
-
-	void setData(const QByteArray &data) {
-		_data = data;
-	}
-	void addData(const QByteArray &data) {
-		_data.append(data);
-	}
-	const QByteArray &data() {
-		return _data;
-	}
-	void setProgress(qint64 already, qint64 size) {
-		_already = already;
-		_size = qMax(size, 0LL);
-	}
-
-	qint64 size() const {
-		return _size;
-	}
-	qint64 already() const {
-		return _already;
-	}
-
-private:
-	static constexpr auto kMaxHttpRedirects = 5;
-
-	webFileLoader *_interface = nullptr;
-	QUrl _url;
-	qint64 _already = 0;
-	qint64 _size = 0;
-	QNetworkReply *_reply = nullptr;
-	int32 _redirectsLeft = kMaxHttpRedirects;
-	QByteArray _data;
-
-	friend class WebLoadManager;
-};
-
-void stopWebLoadManager() {
-	if (webLoadManager()) {
-		_webLoadThread->quit();
-		DEBUG_LOG(("Waiting for webloadThread to finish"));
-		_webLoadThread->wait();
-		delete _webLoadManager;
-		delete _webLoadMainManager;
-		delete _webLoadThread;
-		_webLoadThread = nullptr;
-		_webLoadMainManager = nullptr;
-		_webLoadManager = FinishedWebLoadManager;
-	}
-}
-
-WebLoadManager::WebLoadManager(QThread *thread) {
-	moveToThread(thread);
-	_manager.moveToThread(thread);
-	connect(thread, SIGNAL(started()), this, SLOT(process()));
-	connect(thread, SIGNAL(finished()), this, SLOT(finish()));
-	connect(this, SIGNAL(processDelayed()), this, SLOT(process()), Qt::QueuedConnection);
-
-	connect(this, SIGNAL(progress(webFileLoader*,qint64,qint64)), _webLoadMainManager, SLOT(progress(webFileLoader*,qint64,qint64)));
-	connect(this, SIGNAL(finished(webFileLoader*,QByteArray)), _webLoadMainManager, SLOT(finished(webFileLoader*,QByteArray)));
-	connect(this, SIGNAL(error(webFileLoader*)), _webLoadMainManager, SLOT(error(webFileLoader*)));
-
-	connect(&_manager, SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)), this, SLOT(onFailed(QNetworkReply*)));
-#ifndef OS_MAC_OLD
-	connect(&_manager, SIGNAL(sslErrors(QNetworkReply*,const QList<QSslError>&)), this, SLOT(onFailed(QNetworkReply*)));
-#endif // OS_MAC_OLD
-}
-
-WebLoadManager::~WebLoadManager() {
-	clear();
-}
-
-void WebLoadManager::append(webFileLoader *loader, const QString &url) {
-	loader->_private = new webFileLoaderPrivate(loader, url);
-
-	QMutexLocker lock(&_loaderPointersMutex);
-	_loaderPointers.insert(loader, loader->_private);
-	emit processDelayed();
-}
-
-void WebLoadManager::stop(webFileLoader *loader) {
-	QMutexLocker lock(&_loaderPointersMutex);
-	_loaderPointers.remove(loader);
-	emit processDelayed();
-}
-
-bool WebLoadManager::carries(webFileLoader *loader) const {
-	QMutexLocker lock(&_loaderPointersMutex);
-	return _loaderPointers.contains(loader);
-}
-
-bool WebLoadManager::handleReplyResult(webFileLoaderPrivate *loader, WebReplyProcessResult result) {
-	QMutexLocker lock(&_loaderPointersMutex);
-	LoaderPointers::iterator it = _loaderPointers.find(loader->_interface);
-	if (it != _loaderPointers.cend() && it.key()->_private != loader) {
-		it = _loaderPointers.end(); // it is a new loader which was realloced in the same address
-	}
-	if (it == _loaderPointers.cend()) {
-		return false;
-	}
-
-	if (result == WebReplyProcessProgress) {
-		if (loader->size() > Storage::kMaxFileInMemory) {
-			LOG(("API Error: too large file is loaded to cache: %1").arg(loader->size()));
-			result = WebReplyProcessError;
-		}
-	}
-	if (result == WebReplyProcessError) {
-		if (it != _loaderPointers.cend()) {
-			emit error(it.key());
-		}
-		return false;
-	}
-	if (loader->already() < loader->size() || !loader->size()) {
-		emit progress(it.key(), loader->already(), loader->size());
-		return true;
-	}
-	emit finished(it.key(), loader->data());
-	return false;
-}
-
-void WebLoadManager::onFailed(QNetworkReply::NetworkError error) {
-	onFailed(qobject_cast<QNetworkReply*>(QObject::sender()));
-}
-
-void WebLoadManager::onFailed(QNetworkReply *reply) {
-	if (!reply) return;
-	reply->deleteLater();
-
-	Replies::iterator j = _replies.find(reply);
-	if (j == _replies.cend()) { // handled already
-		return;
-	}
-	webFileLoaderPrivate *loader = j.value();
-	_replies.erase(j);
-
-	LOG(("Network Error: Failed to request '%1', error %2 (%3)").arg(QString::fromLatin1(loader->_url.toEncoded())).arg(int(reply->error())).arg(reply->errorString()));
-
-	if (!handleReplyResult(loader, WebReplyProcessError)) {
-		_loaders.remove(loader);
-		delete loader;
-	}
-}
-
-void WebLoadManager::onProgress(qint64 already, qint64 size) {
-	const auto reply = qobject_cast<QNetworkReply*>(QObject::sender());
-	if (!reply) return;
-
-	const auto j = _replies.find(reply);
-	if (j == _replies.cend()) { // handled already
-		return;
-	}
-	const auto loader = j.value();
-
-	auto result = WebReplyProcessProgress;
-	const auto statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
-	const auto status = statusCode.isValid() ? statusCode.toInt() : 200;
-	if (status != 200 && status != 206 && status != 416) {
-		if (status == 301 || status == 302) {
-			QString loc = reply->header(QNetworkRequest::LocationHeader).toString();
-			if (!loc.isEmpty()) {
-				if (loader->oneMoreRedirect()) {
-					sendRequest(loader, loc);
-					return;
-				} else {
-					LOG(("Network Error: Too many HTTP redirects in onFinished() for web file loader: %1").arg(loc));
-					result = WebReplyProcessError;
-				}
-			}
-		} else {
-			LOG(("Network Error: Bad HTTP status received in WebLoadManager::onProgress(): %1").arg(statusCode.toInt()));
-			result = WebReplyProcessError;
-		}
-	} else {
-		loader->setProgress(already, size);
-		QByteArray r = reply->readAll();
-		if (!r.isEmpty()) {
-			loader->addData(r);
-		}
-		if (size == 0) {
-			LOG(("Network Error: Zero size received for HTTP download progress in WebLoadManager::onProgress(): %1 / %2").arg(already).arg(size));
-			result = WebReplyProcessError;
-		}
-	}
-	if (!handleReplyResult(loader, result)) {
-		_replies.erase(j);
-		_loaders.remove(loader);
-		delete loader;
-
-		reply->abort();
-		reply->deleteLater();
-	}
-}
-
-void WebLoadManager::onMeta() {
-	const auto reply = qobject_cast<QNetworkReply*>(QObject::sender());
-	if (!reply) return;
-
-	const auto j = _replies.find(reply);
-	if (j == _replies.cend()) { // handled already
-		return;
-	}
-	const auto loader = j.value();
-
-	const auto pairs = reply->rawHeaderPairs();
-	for (const auto &pair : pairs) {
-		if (QString::fromUtf8(pair.first).toLower() == "content-range") {
-			const auto m = QRegularExpression(qsl("/(\\d+)([^\\d]|$)")).match(QString::fromUtf8(pair.second));
-			if (m.hasMatch()) {
-				loader->setProgress(qMax(qint64(loader->data().size()), loader->already()), m.captured(1).toLongLong());
-				if (!handleReplyResult(loader, WebReplyProcessProgress)) {
-					_replies.erase(j);
-					_loaders.remove(loader);
-					delete loader;
-
-					reply->abort();
-					reply->deleteLater();
-				}
-			}
-		}
-	}
-}
-
-void WebLoadManager::process() {
-	Loaders newLoaders;
-	{
-		QMutexLocker lock(&_loaderPointersMutex);
-		for (LoaderPointers::iterator i = _loaderPointers.begin(), e = _loaderPointers.end(); i != e; ++i) {
-			Loaders::iterator it = _loaders.find(i.value());
-			if (i.value()) {
-				if (it == _loaders.cend()) {
-					_loaders.insert(i.value());
-					newLoaders.insert(i.value());
-				}
-				i.value() = 0;
-			}
-		}
-		for (auto i = _loaders.begin(), e = _loaders.end(); i != e;) {
-			LoaderPointers::iterator it = _loaderPointers.find((*i)->_interface);
-			if (it != _loaderPointers.cend() && it.key()->_private != (*i)) {
-				it = _loaderPointers.end();
-			}
-			if (it == _loaderPointers.cend()) {
-				if (QNetworkReply *reply = (*i)->reply()) {
-					_replies.remove(reply);
-					reply->abort();
-					reply->deleteLater();
-				}
-				delete (*i);
-				i = _loaders.erase(i);
-			} else {
-				++i;
-			}
-		}
-	}
-	for_const (webFileLoaderPrivate *loader, newLoaders) {
-		if (_loaders.contains(loader)) {
-			sendRequest(loader);
-		}
-	}
-}
-
-void WebLoadManager::sendRequest(webFileLoaderPrivate *loader, const QString &redirect) {
-	Replies::iterator j = _replies.find(loader->reply());
-	if (j != _replies.cend()) {
-		QNetworkReply *r = j.key();
-		_replies.erase(j);
-
-		r->abort();
-		r->deleteLater();
-	}
-
-	QNetworkReply *r = loader->request(_manager, redirect);
-
-	// Those use QObject::sender, so don't just remove the receiver pointer!
-	connect(r, SIGNAL(downloadProgress(qint64, qint64)), this, SLOT(onProgress(qint64, qint64)));
-	connect(r, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(onFailed(QNetworkReply::NetworkError)));
-	connect(r, SIGNAL(metaDataChanged()), this, SLOT(onMeta()));
-
-	_replies.insert(r, loader);
-}
-
-void WebLoadManager::finish() {
-	clear();
-}
-
-void WebLoadManager::clear() {
-	QMutexLocker lock(&_loaderPointersMutex);
-	for (auto i = _loaderPointers.begin(), e = _loaderPointers.end(); i != e; ++i) {
-		if (i.value()) {
-			i.key()->_private = nullptr;
-		}
-	}
-	_loaderPointers.clear();
-
-	for (const auto loader : _loaders) {
-		delete loader;
-	}
-	_loaders.clear();
-
-	for (auto i = _replies.begin(), e = _replies.end(); i != e; ++i) {
-		delete i.key();
-	}
-	_replies.clear();
-}
-
-void WebLoadMainManager::progress(webFileLoader *loader, qint64 already, qint64 size) {
-	if (webLoadManager() && webLoadManager()->carries(loader)) {
-		loader->loadProgress(already, size);
-	}
-}
-
-void WebLoadMainManager::finished(webFileLoader *loader, QByteArray data) {
-	if (webLoadManager() && webLoadManager()->carries(loader)) {
-		loader->loadFinished(data);
-	}
-}
-
-void WebLoadMainManager::error(webFileLoader *loader) {
-	if (webLoadManager() && webLoadManager()->carries(loader)) {
-		loader->loadError();
-	}
-}
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index 520501de9..7f84ff820 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -35,6 +35,12 @@ constexpr auto kMaxWallPaperInMemory = kMaxFileInMemory;
 constexpr auto kMaxAnimationInMemory = kMaxFileInMemory; // 10 MB gif and mp4 animations held in memory while playing
 constexpr auto kMaxWallPaperDimension = 4096; // 4096x4096 is max area.
 
+// Different part sizes are not supported for now :(
+// Because we start downloading with some part size
+// and then we get a cdn-redirect where we support only
+// fixed part size download for hash checking.
+constexpr auto kDownloadPartSize = 128 * 1024;
+
 class Downloader {
 public:
 	virtual ~Downloader() = default;
@@ -114,13 +120,12 @@ struct StorageImageSaved {
 
 };
 
-class FileLoader : public QObject, public Storage::Downloader {
+class FileLoader : public QObject {
 	Q_OBJECT
 
 public:
 	FileLoader(
 		const QString &toFile,
-		MTP::DcId dcId,
 		int32 size,
 		LocationType locationType,
 		LoadToCacheSetting toCache,
@@ -180,8 +185,6 @@ signals:
 	void failed(FileLoader *loader, bool started);
 
 protected:
-	friend class Storage::DownloadManager;
-
 	enum class LocalStatus {
 		NotTried,
 		NotFound,
@@ -189,10 +192,6 @@ protected:
 		Loaded,
 	};
 
-	MTP::DcId dcId() const override {
-		return _dcId;
-	}
-
 	void readImage(const QSize &shrinkBox) const;
 
 	bool tryLoadLocal();
@@ -200,6 +199,7 @@ protected:
 	virtual Storage::Cache::Key cacheKey() const = 0;
 	virtual std::optional<MediaKey> fileLocationKey() const = 0;
 	virtual void cancelRequests() = 0;
+	virtual void startLoading() = 0;
 
 	void cancel(bool failed);
 
@@ -209,8 +209,7 @@ protected:
 	bool finalizeResult();
 	[[nodiscard]] QByteArray readLoadedPartBack(int offset, int size);
 
-	const MTP::DcId _dcId = 0;
-	const not_null<Storage::DownloadManager*> _downloader;
+	const not_null<Main::Session*> _session;
 
 	bool _autoLoading = false;
 	uint8 _cacheTag = 0;
@@ -236,237 +235,3 @@ protected:
 	mutable QImage _imageData;
 
 };
-
-class StorageImageLocation;
-class WebFileLocation;
-class mtpFileLoader final : public FileLoader, public RPCSender {
-public:
-	mtpFileLoader(
-		const StorageFileLocation &location,
-		Data::FileOrigin origin,
-		LocationType type,
-		const QString &toFile,
-		int32 size,
-		LoadToCacheSetting toCache,
-		LoadFromCloudSetting fromCloud,
-		bool autoLoading,
-		uint8 cacheTag);
-	mtpFileLoader(
-		const WebFileLocation &location,
-		int32 size,
-		LoadFromCloudSetting fromCloud,
-		bool autoLoading,
-		uint8 cacheTag);
-	mtpFileLoader(
-		const GeoPointLocation &location,
-		int32 size,
-		LoadFromCloudSetting fromCloud,
-		bool autoLoading,
-		uint8 cacheTag);
-
-	Data::FileOrigin fileOrigin() const override;
-
-	uint64 objId() const override;
-
-	void stop() override {
-		rpcInvalidate();
-	}
-	void refreshFileReferenceFrom(
-		const Data::UpdatedFileReferences &updates,
-		int requestId,
-		const QByteArray &current);
-
-	~mtpFileLoader();
-
-private:
-	friend class DownloadManager;
-
-	struct RequestData {
-		int offset = 0;
-		int dcIndex = 0;
-
-		inline bool operator<(const RequestData &other) const {
-			return offset < other.offset;
-		}
-	};
-	struct CdnFileHash {
-		CdnFileHash(int limit, QByteArray hash) : limit(limit), hash(hash) {
-		}
-		int limit = 0;
-		QByteArray hash;
-	};
-	Storage::Cache::Key cacheKey() const override;
-	std::optional<MediaKey> fileLocationKey() const override;
-	void cancelRequests() override;
-
-	void makeRequest(const RequestData &requestData);
-
-	bool readyToRequest() const override;
-	void loadPart(int dcIndex) override;
-	void normalPartLoaded(const MTPupload_File &result, mtpRequestId requestId);
-	void webPartLoaded(const MTPupload_WebFile &result, mtpRequestId requestId);
-	void cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId);
-	void reuploadDone(const MTPVector<MTPFileHash> &result, mtpRequestId requestId);
-	void requestMoreCdnFileHashes();
-	void getCdnFileHashesDone(const MTPVector<MTPFileHash> &result, mtpRequestId requestId);
-
-	void partLoaded(int offset, bytes::const_span buffer);
-	bool feedPart(int offset, bytes::const_span buffer);
-
-	bool partFailed(const RPCError &error, mtpRequestId requestId);
-	bool normalPartFailed(QByteArray fileReference, const RPCError &error, mtpRequestId requestId);
-	bool cdnPartFailed(const RPCError &error, mtpRequestId requestId);
-
-	mtpRequestId sendRequest(const RequestData &requestData);
-	void placeSentRequest(
-		mtpRequestId requestId,
-		const RequestData &requestData);
-	[[nodiscard]] RequestData finishSentRequest(mtpRequestId requestId);
-	void switchToCDN(
-		const RequestData &requestData,
-		const MTPDupload_fileCdnRedirect &redirect);
-	void addCdnHashes(const QVector<MTPFileHash> &hashes);
-	void changeCDNParams(
-		const RequestData &requestData,
-		MTP::DcId dcId,
-		const QByteArray &token,
-		const QByteArray &encryptionKey,
-		const QByteArray &encryptionIV,
-		const QVector<MTPFileHash> &hashes);
-
-	enum class CheckCdnHashResult {
-		NoHash,
-		Invalid,
-		Good,
-	};
-	CheckCdnHashResult checkCdnFileHash(int offset, bytes::const_span buffer);
-
-	std::map<mtpRequestId, RequestData> _sentRequests;
-
-	bool _lastComplete = false;
-	int32 _nextRequestOffset = 0;
-
-	base::variant<
-		StorageFileLocation,
-		WebFileLocation,
-		GeoPointLocation> _location;
-	Data::FileOrigin _origin;
-
-	MTP::DcId _cdnDcId = 0;
-	QByteArray _cdnToken;
-	QByteArray _cdnEncryptionKey;
-	QByteArray _cdnEncryptionIV;
-	base::flat_map<int, CdnFileHash> _cdnFileHashes;
-	base::flat_map<RequestData, QByteArray> _cdnUncheckedParts;
-	mtpRequestId _cdnHashesRequestId = 0;
-
-};
-
-class webFileLoaderPrivate;
-
-class webFileLoader final : public FileLoader {
-public:
-	webFileLoader(
-		const QString &url,
-		const QString &to,
-		LoadFromCloudSetting fromCloud,
-		bool autoLoading,
-		uint8 cacheTag);
-
-	int currentOffset() const override;
-
-	void loadProgress(qint64 already, qint64 size);
-	void loadFinished(const QByteArray &data);
-	void loadError();
-
-	void stop() override {
-		cancelRequests();
-	}
-
-	~webFileLoader();
-
-private:
-	void cancelRequests() override;
-	Storage::Cache::Key cacheKey() const override;
-	std::optional<MediaKey> fileLocationKey() const override;
-	bool readyToRequest() const override;
-	void loadPart(int dcIndex) override;
-
-	void markAsSent();
-	void markAsNotSent();
-
-	QString _url;
-
-	bool _requestSent = false;
-	int32 _already = 0;
-
-	friend class WebLoadManager;
-	webFileLoaderPrivate *_private = nullptr;
-
-};
-
-enum WebReplyProcessResult {
-	WebReplyProcessError,
-	WebReplyProcessProgress,
-	WebReplyProcessFinished,
-};
-
-class WebLoadManager : public QObject {
-	Q_OBJECT
-
-public:
-	WebLoadManager(QThread *thread);
-
-	void append(webFileLoader *loader, const QString &url);
-	void stop(webFileLoader *reader);
-	bool carries(webFileLoader *reader) const;
-
-	~WebLoadManager();
-
-signals:
-	void processDelayed();
-
-	void progress(webFileLoader *loader, qint64 already, qint64 size);
-	void finished(webFileLoader *loader, QByteArray data);
-	void error(webFileLoader *loader);
-
-public slots:
-	void onFailed(QNetworkReply *reply);
-	void onFailed(QNetworkReply::NetworkError error);
-	void onProgress(qint64 already, qint64 size);
-	void onMeta();
-
-	void process();
-	void finish();
-
-private:
-	void clear();
-	void sendRequest(webFileLoaderPrivate *loader, const QString &redirect = QString());
-	bool handleReplyResult(webFileLoaderPrivate *loader, WebReplyProcessResult result);
-
-	QNetworkAccessManager _manager;
-	typedef QMap<webFileLoader*, webFileLoaderPrivate*> LoaderPointers;
-	LoaderPointers _loaderPointers;
-	mutable QMutex _loaderPointersMutex;
-
-	typedef OrderedSet<webFileLoaderPrivate*> Loaders;
-	Loaders _loaders;
-
-	typedef QMap<QNetworkReply*, webFileLoaderPrivate*> Replies;
-	Replies _replies;
-
-};
-
-class WebLoadMainManager : public QObject {
-	Q_OBJECT
-
-public slots:
-	void progress(webFileLoader *loader, qint64 already, qint64 size);
-	void finished(webFileLoader *loader, QByteArray data);
-	void error(webFileLoader *loader);
-
-};
-
-static WebLoadManager * const FinishedWebLoadManager = SharedMemoryLocation<WebLoadManager, 0>();
-
-void stopWebLoadManager();
diff --git a/Telegram/SourceFiles/storage/file_download_mtproto.cpp b/Telegram/SourceFiles/storage/file_download_mtproto.cpp
new file mode 100644
index 000000000..0cb04513a
--- /dev/null
+++ b/Telegram/SourceFiles/storage/file_download_mtproto.cpp
@@ -0,0 +1,590 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "storage/file_download_mtproto.h"
+
+#include "data/data_document.h"
+#include "data/data_file_origin.h"
+#include "storage/cache/storage_cache_types.h"
+#include "main/main_session.h"
+#include "apiwrap.h"
+#include "mtproto/mtp_instance.h"
+#include "mtproto/mtproto_auth_key.h"
+#include "base/openssl_help.h"
+#include "facades.h"
+
+mtpFileLoader::mtpFileLoader(
+	const StorageFileLocation &location,
+	Data::FileOrigin origin,
+	LocationType type,
+	const QString &to,
+	int32 size,
+	LoadToCacheSetting toCache,
+	LoadFromCloudSetting fromCloud,
+	bool autoLoading,
+	uint8 cacheTag)
+: FileLoader(
+	to,
+	size,
+	type,
+	toCache,
+	fromCloud,
+	autoLoading,
+	cacheTag)
+, _downloader(&session().downloader())
+, _dcId(location.dcId())
+, _location(location)
+, _origin(origin) {
+}
+
+mtpFileLoader::mtpFileLoader(
+	const WebFileLocation &location,
+	int32 size,
+	LoadFromCloudSetting fromCloud,
+	bool autoLoading,
+	uint8 cacheTag)
+: FileLoader(
+	QString(),
+	size,
+	UnknownFileLocation,
+	LoadToCacheAsWell,
+	fromCloud,
+	autoLoading,
+	cacheTag)
+, _downloader(&session().downloader())
+, _dcId(Global::WebFileDcId())
+, _location(location) {
+}
+
+mtpFileLoader::mtpFileLoader(
+	const GeoPointLocation &location,
+	int32 size,
+	LoadFromCloudSetting fromCloud,
+	bool autoLoading,
+	uint8 cacheTag)
+: FileLoader(
+	QString(),
+	size,
+	UnknownFileLocation,
+	LoadToCacheAsWell,
+	fromCloud,
+	autoLoading,
+	cacheTag)
+, _downloader(&session().downloader())
+, _dcId(Global::WebFileDcId())
+, _location(location) {
+}
+
+mtpFileLoader::~mtpFileLoader() {
+	cancelRequests();
+	_downloader->remove(this);
+}
+
+Data::FileOrigin mtpFileLoader::fileOrigin() const {
+	return _origin;
+}
+
+uint64 mtpFileLoader::objId() const {
+	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
+		return storage->objectId();
+	}
+	return 0;
+}
+
+void mtpFileLoader::refreshFileReferenceFrom(
+		const Data::UpdatedFileReferences &updates,
+		int requestId,
+		const QByteArray &current) {
+	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
+		storage->refreshFileReference(updates);
+		if (storage->fileReference() == current) {
+			cancel(true);
+			return;
+		}
+	} else {
+		cancel(true);
+		return;
+	}
+	makeRequest(finishSentRequest(requestId));
+}
+
+MTP::DcId mtpFileLoader::dcId() const {
+	return _dcId;
+}
+
+bool mtpFileLoader::readyToRequest() const {
+	return !_finished
+		&& !_lastComplete
+		&& (_sentRequests.empty() || _size != 0)
+		&& (!_size || _nextRequestOffset < _size);
+}
+
+void mtpFileLoader::loadPart(int dcIndex) {
+	Expects(readyToRequest());
+
+	makeRequest({ _nextRequestOffset, dcIndex });
+	_nextRequestOffset += Storage::kDownloadPartSize;
+}
+
+mtpRequestId mtpFileLoader::sendRequest(const RequestData &requestData) {
+	const auto offset = requestData.offset;
+	const auto limit = Storage::kDownloadPartSize;
+	const auto shiftedDcId = MTP::downloadDcId(
+		_cdnDcId ? _cdnDcId : dcId(),
+		requestData.dcIndex);
+	if (_cdnDcId) {
+		return MTP::send(
+			MTPupload_GetCdnFile(
+				MTP_bytes(_cdnToken),
+				MTP_int(offset),
+				MTP_int(limit)),
+			rpcDone(&mtpFileLoader::cdnPartLoaded),
+			rpcFail(&mtpFileLoader::cdnPartFailed),
+			shiftedDcId,
+			50);
+	}
+	return _location.match([&](const WebFileLocation &location) {
+		return MTP::send(
+			MTPupload_GetWebFile(
+				MTP_inputWebFileLocation(
+					MTP_bytes(location.url()),
+					MTP_long(location.accessHash())),
+				MTP_int(offset),
+				MTP_int(limit)),
+			rpcDone(&mtpFileLoader::webPartLoaded),
+			rpcFail(&mtpFileLoader::partFailed),
+			shiftedDcId,
+			50);
+	}, [&](const GeoPointLocation &location) {
+		return MTP::send(
+			MTPupload_GetWebFile(
+				MTP_inputWebFileGeoPointLocation(
+					MTP_inputGeoPoint(
+						MTP_double(location.lat),
+						MTP_double(location.lon)),
+					MTP_long(location.access),
+					MTP_int(location.width),
+					MTP_int(location.height),
+					MTP_int(location.zoom),
+					MTP_int(location.scale)),
+				MTP_int(offset),
+				MTP_int(limit)),
+			rpcDone(&mtpFileLoader::webPartLoaded),
+			rpcFail(&mtpFileLoader::partFailed),
+			shiftedDcId,
+			50);
+	}, [&](const StorageFileLocation &location) {
+		return MTP::send(
+			MTPupload_GetFile(
+				MTP_flags(0),
+				location.tl(session().userId()),
+				MTP_int(offset),
+				MTP_int(limit)),
+			rpcDone(&mtpFileLoader::normalPartLoaded),
+			rpcFail(
+				&mtpFileLoader::normalPartFailed,
+				location.fileReference()),
+			shiftedDcId,
+			50);
+	});
+}
+
+void mtpFileLoader::makeRequest(const RequestData &requestData) {
+	Expects(!_finished);
+
+	placeSentRequest(sendRequest(requestData), requestData);
+}
+
+void mtpFileLoader::requestMoreCdnFileHashes() {
+	Expects(!_finished);
+
+	if (_cdnHashesRequestId || _cdnUncheckedParts.empty()) {
+		return;
+	}
+
+	const auto requestData = _cdnUncheckedParts.cbegin()->first;
+	const auto shiftedDcId = MTP::downloadDcId(
+		dcId(),
+		requestData.dcIndex);
+	const auto requestId = _cdnHashesRequestId = MTP::send(
+		MTPupload_GetCdnFileHashes(
+			MTP_bytes(_cdnToken),
+			MTP_int(requestData.offset)),
+		rpcDone(&mtpFileLoader::getCdnFileHashesDone),
+		rpcFail(&mtpFileLoader::cdnPartFailed),
+		shiftedDcId);
+	placeSentRequest(requestId, requestData);
+}
+
+void mtpFileLoader::normalPartLoaded(
+		const MTPupload_File &result,
+		mtpRequestId requestId) {
+	Expects(!_finished);
+
+	const auto requestData = finishSentRequest(requestId);
+	result.match([&](const MTPDupload_fileCdnRedirect &data) {
+		switchToCDN(requestData, data);
+	}, [&](const MTPDupload_file &data) {
+		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
+	});
+}
+
+void mtpFileLoader::webPartLoaded(
+		const MTPupload_WebFile &result,
+		mtpRequestId requestId) {
+	result.match([&](const MTPDupload_webFile &data) {
+		const auto requestData = finishSentRequest(requestId);
+		if (!_size) {
+			_size = data.vsize().v;
+		} else if (data.vsize().v != _size) {
+			LOG(("MTP Error: "
+				"Bad size provided by bot for webDocument: %1, real: %2"
+				).arg(_size
+				).arg(data.vsize().v));
+			cancel(true);
+			return;
+		}
+		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
+	});
+}
+
+void mtpFileLoader::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId) {
+	Expects(!_finished);
+
+	const auto requestData = finishSentRequest(requestId);
+	result.match([&](const MTPDupload_cdnFileReuploadNeeded &data) {
+		const auto shiftedDcId = MTP::downloadDcId(
+			dcId(),
+			requestData.dcIndex);
+		const auto requestId = MTP::send(
+			MTPupload_ReuploadCdnFile(
+				MTP_bytes(_cdnToken),
+				data.vrequest_token()),
+			rpcDone(&mtpFileLoader::reuploadDone),
+			rpcFail(&mtpFileLoader::cdnPartFailed),
+			shiftedDcId);
+		placeSentRequest(requestId, requestData);
+	}, [&](const MTPDupload_cdnFile &data) {
+		auto key = bytes::make_span(_cdnEncryptionKey);
+		auto iv = bytes::make_span(_cdnEncryptionIV);
+		Expects(key.size() == MTP::CTRState::KeySize);
+		Expects(iv.size() == MTP::CTRState::IvecSize);
+
+		auto state = MTP::CTRState();
+		auto ivec = bytes::make_span(state.ivec);
+		std::copy(iv.begin(), iv.end(), ivec.begin());
+
+		auto counterOffset = static_cast<uint32>(requestData.offset) >> 4;
+		state.ivec[15] = static_cast<uchar>(counterOffset & 0xFF);
+		state.ivec[14] = static_cast<uchar>((counterOffset >> 8) & 0xFF);
+		state.ivec[13] = static_cast<uchar>((counterOffset >> 16) & 0xFF);
+		state.ivec[12] = static_cast<uchar>((counterOffset >> 24) & 0xFF);
+
+		auto decryptInPlace = data.vbytes().v;
+		auto buffer = bytes::make_detached_span(decryptInPlace);
+		MTP::aesCtrEncrypt(buffer, key.data(), &state);
+
+		switch (checkCdnFileHash(requestData.offset, buffer)) {
+		case CheckCdnHashResult::NoHash: {
+			_cdnUncheckedParts.emplace(requestData, decryptInPlace);
+			requestMoreCdnFileHashes();
+		} return;
+
+		case CheckCdnHashResult::Invalid: {
+			LOG(("API Error: Wrong cdnFileHash for offset %1."
+				).arg(requestData.offset));
+			cancel(true);
+		} return;
+
+		case CheckCdnHashResult::Good: {
+			partLoaded(requestData.offset, buffer);
+		} return;
+		}
+		Unexpected("Result of checkCdnFileHash()");
+	});
+}
+
+mtpFileLoader::CheckCdnHashResult mtpFileLoader::checkCdnFileHash(
+		int offset,
+		bytes::const_span buffer) {
+	const auto cdnFileHashIt = _cdnFileHashes.find(offset);
+	if (cdnFileHashIt == _cdnFileHashes.cend()) {
+		return CheckCdnHashResult::NoHash;
+	}
+	const auto realHash = openssl::Sha256(buffer);
+	const auto receivedHash = bytes::make_span(cdnFileHashIt->second.hash);
+	if (bytes::compare(realHash, receivedHash)) {
+		return CheckCdnHashResult::Invalid;
+	}
+	return CheckCdnHashResult::Good;
+}
+
+void mtpFileLoader::reuploadDone(
+		const MTPVector<MTPFileHash> &result,
+		mtpRequestId requestId) {
+	const auto requestData = finishSentRequest(requestId);
+	addCdnHashes(result.v);
+	makeRequest(requestData);
+}
+
+void mtpFileLoader::getCdnFileHashesDone(
+		const MTPVector<MTPFileHash> &result,
+		mtpRequestId requestId) {
+	Expects(!_finished);
+	Expects(_cdnHashesRequestId == requestId);
+
+	_cdnHashesRequestId = 0;
+
+	const auto requestData = finishSentRequest(requestId);
+	addCdnHashes(result.v);
+	auto someMoreChecked = false;
+	for (auto i = _cdnUncheckedParts.begin(); i != _cdnUncheckedParts.cend();) {
+		const auto uncheckedData = i->first;
+		const auto uncheckedBytes = bytes::make_span(i->second);
+
+		switch (checkCdnFileHash(uncheckedData.offset, uncheckedBytes)) {
+		case CheckCdnHashResult::NoHash: {
+			++i;
+		} break;
+
+		case CheckCdnHashResult::Invalid: {
+			LOG(("API Error: Wrong cdnFileHash for offset %1."
+				).arg(uncheckedData.offset));
+			cancel(true);
+			return;
+		} break;
+
+		case CheckCdnHashResult::Good: {
+			someMoreChecked = true;
+			const auto goodOffset = uncheckedData.offset;
+			const auto goodBytes = std::move(i->second);
+			const auto weak = QPointer<mtpFileLoader>(this);
+			i = _cdnUncheckedParts.erase(i);
+			if (!feedPart(goodOffset, bytes::make_span(goodBytes))
+				|| !weak) {
+				return;
+			} else if (_finished) {
+				notifyAboutProgress();
+				return;
+			}
+		} break;
+
+		default: Unexpected("Result of checkCdnFileHash()");
+		}
+	}
+	if (someMoreChecked) {
+		const auto weak = QPointer<mtpFileLoader>(this);
+		notifyAboutProgress();
+		if (weak) {
+			requestMoreCdnFileHashes();
+		}
+		return;
+	}
+	LOG(("API Error: "
+		"Could not find cdnFileHash for offset %1 "
+		"after getCdnFileHashes request."
+		).arg(requestData.offset));
+	cancel(true);
+}
+
+void mtpFileLoader::placeSentRequest(
+		mtpRequestId requestId,
+		const RequestData &requestData) {
+	Expects(!_finished);
+
+	_downloader->requestedAmountIncrement(
+		dcId(),
+		requestData.dcIndex,
+		Storage::kDownloadPartSize);
+	_sentRequests.emplace(requestId, requestData);
+}
+
+auto mtpFileLoader::finishSentRequest(mtpRequestId requestId)
+-> RequestData {
+	auto it = _sentRequests.find(requestId);
+	Assert(it != _sentRequests.cend());
+
+	const auto result = it->second;
+	_downloader->requestedAmountIncrement(
+		dcId(),
+		result.dcIndex,
+		-Storage::kDownloadPartSize);
+	_sentRequests.erase(it);
+
+	return result;
+}
+
+bool mtpFileLoader::feedPart(int offset, bytes::const_span buffer) {
+	if (!writeResultPart(offset, buffer)) {
+		return false;
+	}
+	if (buffer.empty() || (buffer.size() % 1024)) { // bad next offset
+		_lastComplete = true;
+	}
+	const auto finished = _sentRequests.empty()
+		&& _cdnUncheckedParts.empty()
+		&& (_lastComplete || (_size && _nextRequestOffset >= _size));
+	if (finished) {
+		_downloader->remove(this);
+		if (!finalizeResult()) {
+			return false;
+		}
+	}
+	return true;
+}
+
+void mtpFileLoader::partLoaded(int offset, bytes::const_span buffer) {
+	if (feedPart(offset, buffer)) {
+		notifyAboutProgress();
+	}
+}
+
+bool mtpFileLoader::normalPartFailed(
+		QByteArray fileReference,
+		const RPCError &error,
+		mtpRequestId requestId) {
+	if (MTP::isDefaultHandledError(error)) {
+		return false;
+	}
+	if (error.code() == 400
+		&& error.type().startsWith(qstr("FILE_REFERENCE_"))) {
+		session().api().refreshFileReference(
+			_origin,
+			this,
+			requestId,
+			fileReference);
+		return true;
+	}
+	return partFailed(error, requestId);
+}
+
+
+bool mtpFileLoader::partFailed(
+		const RPCError &error,
+		mtpRequestId requestId) {
+	if (MTP::isDefaultHandledError(error)) {
+		return false;
+	}
+	cancel(true);
+	return true;
+}
+
+bool mtpFileLoader::cdnPartFailed(
+		const RPCError &error,
+		mtpRequestId requestId) {
+	if (MTP::isDefaultHandledError(error)) {
+		return false;
+	}
+
+	if (requestId == _cdnHashesRequestId) {
+		_cdnHashesRequestId = 0;
+	}
+	if (error.type() == qstr("FILE_TOKEN_INVALID")
+		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
+		const auto requestData = finishSentRequest(requestId);
+		changeCDNParams(
+			requestData,
+			0,
+			QByteArray(),
+			QByteArray(),
+			QByteArray(),
+			QVector<MTPFileHash>());
+		return true;
+	}
+	return partFailed(error, requestId);
+}
+
+void mtpFileLoader::startLoading() {
+	_downloader->enqueue(this);
+}
+
+void mtpFileLoader::cancelRequests() {
+	while (!_sentRequests.empty()) {
+		auto requestId = _sentRequests.begin()->first;
+		MTP::cancel(requestId);
+		[[maybe_unused]] const auto data = finishSentRequest(requestId);
+	}
+}
+
+void mtpFileLoader::switchToCDN(
+		const RequestData &requestData,
+		const MTPDupload_fileCdnRedirect &redirect) {
+	changeCDNParams(
+		requestData,
+		redirect.vdc_id().v,
+		redirect.vfile_token().v,
+		redirect.vencryption_key().v,
+		redirect.vencryption_iv().v,
+		redirect.vfile_hashes().v);
+}
+
+void mtpFileLoader::addCdnHashes(const QVector<MTPFileHash> &hashes) {
+	for (const auto &hash : hashes) {
+		hash.match([&](const MTPDfileHash &data) {
+			_cdnFileHashes.emplace(
+				data.voffset().v,
+				CdnFileHash{ data.vlimit().v, data.vhash().v });
+		});
+	}
+}
+
+void mtpFileLoader::changeCDNParams(
+		const RequestData &requestData,
+		MTP::DcId dcId,
+		const QByteArray &token,
+		const QByteArray &encryptionKey,
+		const QByteArray &encryptionIV,
+		const QVector<MTPFileHash> &hashes) {
+	if (dcId != 0
+		&& (encryptionKey.size() != MTP::CTRState::KeySize
+			|| encryptionIV.size() != MTP::CTRState::IvecSize)) {
+		LOG(("Message Error: Wrong key (%1) / iv (%2) size in CDN params").arg(encryptionKey.size()).arg(encryptionIV.size()));
+		cancel(true);
+		return;
+	}
+
+	auto resendAllRequests = (_cdnDcId != dcId
+		|| _cdnToken != token
+		|| _cdnEncryptionKey != encryptionKey
+		|| _cdnEncryptionIV != encryptionIV);
+	_cdnDcId = dcId;
+	_cdnToken = token;
+	_cdnEncryptionKey = encryptionKey;
+	_cdnEncryptionIV = encryptionIV;
+	addCdnHashes(hashes);
+
+	if (resendAllRequests && !_sentRequests.empty()) {
+		auto resendRequests = std::vector<RequestData>();
+		resendRequests.reserve(_sentRequests.size());
+		while (!_sentRequests.empty()) {
+			auto requestId = _sentRequests.begin()->first;
+			MTP::cancel(requestId);
+			resendRequests.push_back(finishSentRequest(requestId));
+		}
+		for (const auto &requestData : resendRequests) {
+			makeRequest(requestData);
+		}
+	}
+	makeRequest(requestData);
+}
+
+Storage::Cache::Key mtpFileLoader::cacheKey() const {
+	return _location.match([&](const WebFileLocation &location) {
+		return Data::WebDocumentCacheKey(location);
+	}, [&](const GeoPointLocation &location) {
+		return Data::GeoPointCacheKey(location);
+	}, [&](const StorageFileLocation &location) {
+		return location.cacheKey();
+	});
+}
+
+std::optional<MediaKey> mtpFileLoader::fileLocationKey() const {
+	if (_locationType != UnknownFileLocation) {
+		return mediaKey(_locationType, dcId(), objId());
+	}
+	return std::nullopt;
+}
diff --git a/Telegram/SourceFiles/storage/file_download_mtproto.h b/Telegram/SourceFiles/storage/file_download_mtproto.h
new file mode 100644
index 000000000..01cadd3b2
--- /dev/null
+++ b/Telegram/SourceFiles/storage/file_download_mtproto.h
@@ -0,0 +1,140 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "storage/file_download.h"
+
+class StorageImageLocation;
+class WebFileLocation;
+class mtpFileLoader final
+	: public FileLoader
+	, public RPCSender
+	, public Storage::Downloader {
+public:
+	mtpFileLoader(
+		const StorageFileLocation &location,
+		Data::FileOrigin origin,
+		LocationType type,
+		const QString &toFile,
+		int32 size,
+		LoadToCacheSetting toCache,
+		LoadFromCloudSetting fromCloud,
+		bool autoLoading,
+		uint8 cacheTag);
+	mtpFileLoader(
+		const WebFileLocation &location,
+		int32 size,
+		LoadFromCloudSetting fromCloud,
+		bool autoLoading,
+		uint8 cacheTag);
+	mtpFileLoader(
+		const GeoPointLocation &location,
+		int32 size,
+		LoadFromCloudSetting fromCloud,
+		bool autoLoading,
+		uint8 cacheTag);
+
+	Data::FileOrigin fileOrigin() const override;
+
+	uint64 objId() const override;
+
+	void stop() override {
+		rpcInvalidate();
+	}
+	void refreshFileReferenceFrom(
+		const Data::UpdatedFileReferences &updates,
+		int requestId,
+		const QByteArray &current);
+
+	~mtpFileLoader();
+
+private:
+	struct RequestData {
+		int offset = 0;
+		int dcIndex = 0;
+
+		inline bool operator<(const RequestData &other) const {
+			return offset < other.offset;
+		}
+	};
+	struct CdnFileHash {
+		CdnFileHash(int limit, QByteArray hash) : limit(limit), hash(hash) {
+		}
+		int limit = 0;
+		QByteArray hash;
+	};
+	Storage::Cache::Key cacheKey() const override;
+	std::optional<MediaKey> fileLocationKey() const override;
+	void startLoading() override;
+	void cancelRequests() override;
+
+	void makeRequest(const RequestData &requestData);
+
+	MTP::DcId dcId() const override;
+	bool readyToRequest() const override;
+	void loadPart(int dcIndex) override;
+	void normalPartLoaded(const MTPupload_File &result, mtpRequestId requestId);
+	void webPartLoaded(const MTPupload_WebFile &result, mtpRequestId requestId);
+	void cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId);
+	void reuploadDone(const MTPVector<MTPFileHash> &result, mtpRequestId requestId);
+	void requestMoreCdnFileHashes();
+	void getCdnFileHashesDone(const MTPVector<MTPFileHash> &result, mtpRequestId requestId);
+
+	void partLoaded(int offset, bytes::const_span buffer);
+	bool feedPart(int offset, bytes::const_span buffer);
+
+	bool partFailed(const RPCError &error, mtpRequestId requestId);
+	bool normalPartFailed(QByteArray fileReference, const RPCError &error, mtpRequestId requestId);
+	bool cdnPartFailed(const RPCError &error, mtpRequestId requestId);
+
+	mtpRequestId sendRequest(const RequestData &requestData);
+	void placeSentRequest(
+		mtpRequestId requestId,
+		const RequestData &requestData);
+	[[nodiscard]] RequestData finishSentRequest(mtpRequestId requestId);
+	void switchToCDN(
+		const RequestData &requestData,
+		const MTPDupload_fileCdnRedirect &redirect);
+	void addCdnHashes(const QVector<MTPFileHash> &hashes);
+	void changeCDNParams(
+		const RequestData &requestData,
+		MTP::DcId dcId,
+		const QByteArray &token,
+		const QByteArray &encryptionKey,
+		const QByteArray &encryptionIV,
+		const QVector<MTPFileHash> &hashes);
+
+	enum class CheckCdnHashResult {
+		NoHash,
+		Invalid,
+		Good,
+	};
+	CheckCdnHashResult checkCdnFileHash(int offset, bytes::const_span buffer);
+
+	const not_null<Storage::DownloadManager*> _downloader;
+	const MTP::DcId _dcId = 0;
+	std::map<mtpRequestId, RequestData> _sentRequests;
+
+	bool _lastComplete = false;
+	int32 _nextRequestOffset = 0;
+
+	base::variant<
+		StorageFileLocation,
+		WebFileLocation,
+		GeoPointLocation> _location;
+	Data::FileOrigin _origin;
+
+	MTP::DcId _cdnDcId = 0;
+	QByteArray _cdnToken;
+	QByteArray _cdnEncryptionKey;
+	QByteArray _cdnEncryptionIV;
+	base::flat_map<int, CdnFileHash> _cdnFileHashes;
+	base::flat_map<RequestData, QByteArray> _cdnUncheckedParts;
+	mtpRequestId _cdnHashesRequestId = 0;
+
+};
diff --git a/Telegram/SourceFiles/storage/file_download_web.cpp b/Telegram/SourceFiles/storage/file_download_web.cpp
new file mode 100644
index 000000000..e9714236a
--- /dev/null
+++ b/Telegram/SourceFiles/storage/file_download_web.cpp
@@ -0,0 +1,527 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "storage/file_download_web.h"
+
+#include "storage/cache/storage_cache_types.h"
+
+#include <QtNetwork/QAuthenticator>
+
+namespace {
+
+constexpr auto kMaxWebFileQueries = 8;
+constexpr auto kMaxHttpRedirects = 5;
+constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
+
+std::weak_ptr<WebLoadManager> GlobalLoadManager;
+
+using ErrorSignal = void(QNetworkReply::*)(QNetworkReply::NetworkError);
+const auto QNetworkReply_error = ErrorSignal(&QNetworkReply::error);
+
+[[nodiscard]] std::shared_ptr<WebLoadManager> GetManager() {
+	auto result = GlobalLoadManager.lock();
+	if (!result) {
+		GlobalLoadManager = result = std::make_shared<WebLoadManager>();
+	}
+	return result;
+}
+
+enum class ProcessResult {
+	Error,
+	Progress,
+	Finished,
+};
+
+enum class Error {
+};
+
+struct Progress {
+	qint64 ready = 0;
+	qint64 total = 0;
+};
+
+using Update = base::variant<Progress, QByteArray, Error>;
+
+struct UpdateForLoader {
+	not_null<webFileLoader*> loader;
+	Update data;
+};
+
+} // namespace
+
+class WebLoadManager final : public QObject {
+public:
+	WebLoadManager();
+	~WebLoadManager();
+
+	void enqueue(not_null<webFileLoader*> loader);
+	void remove(not_null<webFileLoader*> loader);
+
+	[[nodiscard]] rpl::producer<Update> updates(
+		not_null<webFileLoader*> loader) const;
+
+private:
+	struct Enqueued {
+		int id = 0;
+		QString url;
+	};
+	struct Sent {
+		QString url;
+		not_null<QNetworkReply*> reply;
+		QByteArray data;
+		int64 ready = 0;
+		int64 total = 0;
+		int redirectsLeft = kMaxHttpRedirects;
+	};
+
+	// Constructor.
+	void handleNetworkErrors();
+
+	// Worker thread.
+	void enqueue(int id, const QString &url);
+	void remove(int id);
+	void resetGeneration();
+	void checkSendNext();
+	void send(const Enqueued &entry);
+	[[nodiscard]] not_null<QNetworkReply*> send(int id, const QString &url);
+	[[nodiscard]] Sent *findSent(int id, not_null<QNetworkReply*> reply);
+	void removeSent(int id);
+	void progress(
+		int id,
+		not_null<QNetworkReply*> reply,
+		int64 ready,
+		int64 total);
+	void failed(
+		int id,
+		not_null<QNetworkReply*> reply,
+		QNetworkReply::NetworkError error);
+	void redirect(int id, not_null<QNetworkReply*> reply);
+	void notify(
+		int id,
+		not_null<QNetworkReply*> reply,
+		int64 ready,
+		int64 total);
+	void failed(int id, not_null<QNetworkReply*> reply);
+	void finished(int id, not_null<QNetworkReply*> reply);
+	void deleteDeferred(not_null<QNetworkReply*> reply);
+	void queueProgressUpdate(int id, int64 ready, int64 total);
+	void queueFailedUpdate(int id);
+	void queueFinishedUpdate(int id, const QByteArray &data);
+	void clear();
+
+	// Main thread.
+	void sendUpdate(int id, Update &&data);
+
+	QThread _thread;
+	QNetworkAccessManager _network;
+	base::Timer _resetGenerationTimer;
+
+	// Main thread.
+	rpl::event_stream<UpdateForLoader> _updates;
+	int _autoincrement = 0;
+	base::flat_map<not_null<webFileLoader*>, int> _ids;
+
+	// Worker thread.
+	std::deque<Enqueued> _queue;
+	std::deque<Enqueued> _previousGeneration;
+	base::flat_map<int, Sent> _sent;
+	std::vector<QPointer<QNetworkReply>> _repliesBeingDeleted;
+
+};
+
+WebLoadManager::WebLoadManager()
+: _resetGenerationTimer(&_thread, [=] { resetGeneration(); }) {
+	handleNetworkErrors();
+
+	const auto original = QThread::currentThread();
+	moveToThread(&_thread);
+	_network.moveToThread(&_thread);
+	connect(&_thread, &QThread::finished, [=] {
+		clear();
+		moveToThread(original);
+		_network.moveToThread(original);
+	});
+	_thread.start();
+}
+
+void WebLoadManager::handleNetworkErrors() {
+	const auto fail = [=](QNetworkReply *reply) {
+		for (const auto &[id, sent] : _sent) {
+			if (sent.reply == reply) {
+				failed(id, reply);
+				return;
+			}
+		}
+	};
+	connect(&_network, &QNetworkAccessManager::authenticationRequired, fail);
+	connect(&_network, &QNetworkAccessManager::sslErrors, fail);
+}
+
+WebLoadManager::~WebLoadManager() {
+	_thread.quit();
+	_thread.wait();
+}
+
+[[nodiscard]] rpl::producer<Update> WebLoadManager::updates(
+		not_null<webFileLoader*> loader) const {
+	return _updates.events(
+	) | rpl::filter([=](const UpdateForLoader &update) {
+		return (update.loader == loader);
+	}) | rpl::map([=](UpdateForLoader &&update) {
+		return std::move(update.data);
+	});
+}
+
+void WebLoadManager::enqueue(not_null<webFileLoader*> loader) {
+	const auto id = [&] {
+		const auto i = _ids.find(loader);
+		return (i != end(_ids))
+			? i->second
+			: _ids.emplace(loader, ++_autoincrement).first->second;
+	}();
+	const auto url = loader->url();
+	InvokeQueued(this, [=] {
+		enqueue(id, url);
+	});
+}
+
+void WebLoadManager::remove(not_null<webFileLoader*> loader) {
+	const auto i = _ids.find(loader);
+	if (i == end(_ids)) {
+		return;
+	}
+	const auto id = i->second;
+	_ids.erase(i);
+	InvokeQueued(this, [=] {
+		remove(id);
+	});
+}
+
+void WebLoadManager::enqueue(int id, const QString &url) {
+	const auto i = ranges::find(_queue, id, &Enqueued::id);
+	if (i != end(_queue)) {
+		return;
+	}
+	_previousGeneration.erase(
+		ranges::remove(_previousGeneration, id, &Enqueued::id),
+		end(_previousGeneration));
+	_queue.push_back(Enqueued{ id, url });
+	if (!_resetGenerationTimer.isActive()) {
+		_resetGenerationTimer.callOnce(kResetDownloadPrioritiesTimeout);
+	}
+	checkSendNext();
+}
+
+void WebLoadManager::remove(int id) {
+	_queue.erase(ranges::remove(_queue, id, &Enqueued::id), end(_queue));
+	_previousGeneration.erase(
+		ranges::remove(_previousGeneration, id, &Enqueued::id),
+		end(_previousGeneration));
+	removeSent(id);
+	checkSendNext();
+}
+
+void WebLoadManager::resetGeneration() {
+	if (!_previousGeneration.empty()) {
+		std::copy(
+			begin(_previousGeneration),
+			end(_previousGeneration),
+			std::back_inserter(_queue));
+		_previousGeneration.clear();
+	}
+	std::swap(_queue, _previousGeneration);
+}
+
+void WebLoadManager::checkSendNext() {
+	if (_sent.size() >= kMaxWebFileQueries
+		|| (_queue.empty() && _previousGeneration.empty())) {
+		return;
+	}
+	const auto entry = _queue.empty()
+		? _previousGeneration.front()
+		: _queue.front();
+	(_queue.empty() ? _previousGeneration : _queue).pop_front();
+	send(entry);
+}
+
+void WebLoadManager::send(const Enqueued &entry) {
+	const auto id = entry.id;
+	const auto url = entry.url;
+	_sent.emplace(id, Sent{ url, send(id, url) });
+}
+
+void WebLoadManager::removeSent(int id) {
+	if (const auto i = _sent.find(id); i != end(_sent)) {
+		deleteDeferred(i->second.reply);
+		_sent.erase(i);
+	}
+}
+
+not_null<QNetworkReply*> WebLoadManager::send(int id, const QString &url) {
+	const auto result = _network.get(QNetworkRequest(url));
+	const auto handleProgress = [=](qint64 ready, qint64 total) {
+		progress(id, result, ready, total);
+		checkSendNext();
+	};
+	const auto handleError = [=](QNetworkReply::NetworkError error) {
+		failed(id, result, error);
+		checkSendNext();
+	};
+	connect(result, &QNetworkReply::downloadProgress, handleProgress);
+	connect(result, QNetworkReply_error, handleError);
+	return result;
+}
+
+WebLoadManager::Sent *WebLoadManager::findSent(
+		int id,
+		not_null<QNetworkReply*> reply) {
+	const auto i = _sent.find(id);
+	return (i != end(_sent) && i->second.reply == reply)
+		? &i->second
+		: nullptr;
+}
+
+void WebLoadManager::progress(
+		int id,
+		not_null<QNetworkReply*> reply,
+		int64 ready,
+		int64 total) {
+	const auto statusCode = reply->attribute(
+		QNetworkRequest::HttpStatusCodeAttribute);
+	const auto status = statusCode.isValid() ? statusCode.toInt() : 200;
+	if (status == 301 || status == 302) {
+		redirect(id, reply);
+	} else if (status != 200 && status != 206 && status != 416) {
+		LOG(("Network Error: "
+			"Bad HTTP status received in WebLoadManager::onProgress() %1"
+			).arg(status));
+		failed(id, reply);
+	} else {
+		notify(id, reply, ready, total);
+	}
+}
+
+void WebLoadManager::redirect(int id, not_null<QNetworkReply*> reply) {
+	const auto header = reply->header(QNetworkRequest::LocationHeader);
+	const auto url = header.toString();
+	if (url.isEmpty()) {
+		return;
+	}
+
+	if (const auto sent = findSent(id, reply)) {
+		if (!sent->redirectsLeft--) {
+			LOG(("Network Error: "
+				"Too many HTTP redirects in onFinished() "
+				"for web file loader: %1").arg(url));
+			failed(id, reply);
+			return;
+		}
+		deleteDeferred(reply);
+		sent->url = url;
+		sent->reply = send(id, url);
+	}
+}
+
+void WebLoadManager::notify(
+		int id,
+		not_null<QNetworkReply*> reply,
+		int64 ready,
+		int64 total) {
+	if (const auto sent = findSent(id, reply)) {
+		sent->ready = ready;
+		sent->total = std::max(total, int64(0));
+		sent->data.append(reply->readAll());
+		if (total == 0
+			|| total > Storage::kMaxFileInMemory
+			|| sent->data.size() > Storage::kMaxFileInMemory) {
+			LOG(("Network Error: "
+				"Bad size received for HTTP download progress "
+				"in WebLoadManager::onProgress(): %1 / %2 (bytes %3)"
+				).arg(ready
+				).arg(total
+				).arg(sent->data.size()));
+			failed(id, reply);
+		} else if (total > 0 && ready >= total) {
+			finished(id, reply);
+		} else {
+			queueProgressUpdate(id, sent->ready, sent->total);
+		}
+	}
+}
+
+void WebLoadManager::failed(
+		int id,
+		not_null<QNetworkReply*> reply,
+		QNetworkReply::NetworkError error) {
+	if (const auto sent = findSent(id, reply)) {
+		LOG(("Network Error: "
+			"Failed to request '%1', error %2 (%3)"
+			).arg(sent->url
+			).arg(int(error)
+			).arg(reply->errorString()));
+		failed(id, reply);
+	}
+}
+
+void WebLoadManager::failed(int id, not_null<QNetworkReply*> reply) {
+	if (const auto sent = findSent(id, reply)) {
+		removeSent(id);
+		queueFailedUpdate(id);
+	}
+}
+
+void WebLoadManager::deleteDeferred(not_null<QNetworkReply*> reply) {
+	reply->deleteLater();
+	_repliesBeingDeleted.erase(
+		ranges::remove(_repliesBeingDeleted, nullptr),
+		end(_repliesBeingDeleted));
+	_repliesBeingDeleted.emplace_back(reply.get());
+}
+
+void WebLoadManager::finished(int id, not_null<QNetworkReply*> reply) {
+	if (const auto sent = findSent(id, reply)) {
+		const auto data = base::take(sent->data);
+		removeSent(id);
+		queueFinishedUpdate(id, data);
+	}
+}
+
+void WebLoadManager::clear() {
+	for (const auto &[id, sent] : base::take(_sent)) {
+		sent.reply->abort();
+		delete sent.reply;
+	}
+	for (const auto reply : base::take(_repliesBeingDeleted)) {
+		if (reply) {
+			delete reply;
+		}
+	}
+}
+
+void WebLoadManager::queueProgressUpdate(int id, int64 ready, int64 total) {
+	crl::on_main(this, [=] {
+		sendUpdate(id, Progress{ ready, total });
+	});
+}
+
+void WebLoadManager::queueFailedUpdate(int id) {
+	crl::on_main(this, [=] {
+		sendUpdate(id, Error{});
+	});
+}
+
+void WebLoadManager::queueFinishedUpdate(int id, const QByteArray &data) {
+	crl::on_main(this, [=] {
+		LOG(("FINISHED UPDATE FOR: %1").arg(id));
+		for (const auto &[loader, loaderId] : _ids) {
+			if (loaderId == id) {
+				LOG(("LOADER ID: %2").arg(quintptr(loader.get())));
+				break;
+			}
+		}
+		LOG(("SENT"));
+		sendUpdate(id, QByteArray(data));
+	});
+}
+
+void WebLoadManager::sendUpdate(int id, Update &&data) {
+	for (const auto &[loader, loaderId] : _ids) {
+		if (loaderId == id) {
+			_updates.fire(UpdateForLoader{ loader, std::move(data) });
+			return;
+		}
+	}
+}
+
+webFileLoader::webFileLoader(
+	const QString &url,
+	const QString &to,
+	LoadFromCloudSetting fromCloud,
+	bool autoLoading,
+	uint8 cacheTag)
+: FileLoader(
+	QString(),
+	0,
+	UnknownFileLocation,
+	LoadToCacheAsWell,
+	fromCloud,
+	autoLoading,
+	cacheTag)
+, _url(url) {
+}
+
+webFileLoader::~webFileLoader() {
+	cancelRequests();
+}
+
+QString webFileLoader::url() const {
+	return _url;
+}
+
+void webFileLoader::startLoading() {
+	if (_finished) {
+		return;
+	} else if (!_manager) {
+		_manager = GetManager();
+		_manager->updates(
+			this
+		) | rpl::start_with_next([=](const Update &data) {
+			if (const auto progress = base::get_if<Progress>(&data)) {
+				loadProgress(progress->ready, progress->total);
+			} else if (const auto bytes = base::get_if<QByteArray>(&data)) {
+				loadFinished(*bytes);
+			} else {
+				loadFailed();
+			}
+		}, _managerLifetime);
+	}
+	_manager->enqueue(this);
+}
+
+int webFileLoader::currentOffset() const {
+	return _ready;
+}
+
+void webFileLoader::loadProgress(qint64 ready, qint64 total) {
+	_size = total;
+	_ready = ready;
+	notifyAboutProgress();
+}
+
+void webFileLoader::loadFinished(const QByteArray &data) {
+	cancelRequests();
+	if (writeResultPart(0, bytes::make_span(data))) {
+		if (finalizeResult()) {
+			notifyAboutProgress();
+		}
+	}
+}
+
+void webFileLoader::loadFailed() {
+	cancel(true);
+}
+
+Storage::Cache::Key webFileLoader::cacheKey() const {
+	return Data::UrlCacheKey(_url);
+}
+
+std::optional<MediaKey> webFileLoader::fileLocationKey() const {
+	return std::nullopt;
+}
+
+void webFileLoader::stop() {
+	cancelRequests();
+}
+
+void webFileLoader::cancelRequests() {
+	if (!_manager) {
+		return;
+	}
+	_managerLifetime.destroy();
+	_manager->remove(this);
+	_manager = nullptr;
+}
diff --git a/Telegram/SourceFiles/storage/file_download_web.h b/Telegram/SourceFiles/storage/file_download_web.h
new file mode 100644
index 000000000..bfc1b8638
--- /dev/null
+++ b/Telegram/SourceFiles/storage/file_download_web.h
@@ -0,0 +1,45 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "storage/file_download.h"
+
+class WebLoadManager;
+
+class webFileLoader final : public FileLoader {
+public:
+	webFileLoader(
+		const QString &url,
+		const QString &to,
+		LoadFromCloudSetting fromCloud,
+		bool autoLoading,
+		uint8 cacheTag);
+	~webFileLoader();
+
+	[[nodiscard]] QString url() const;
+
+	int currentOffset() const override;
+	void stop() override;
+	void cancelRequests() override;
+
+private:
+	void startLoading() override;
+	Storage::Cache::Key cacheKey() const override;
+	std::optional<MediaKey> fileLocationKey() const override;
+
+	void loadProgress(qint64 ready, qint64 size);
+	void loadFinished(const QByteArray &data);
+	void loadFailed();
+
+	const QString _url;
+	int _ready = 0;
+
+	std::shared_ptr<WebLoadManager> _manager;
+	rpl::lifetime _managerLifetime;
+
+};
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
index 33b15bb54..d5afb2a43 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
@@ -38,7 +38,6 @@ StreamedFileDownloader::StreamedFileDownloader(
 	uint8 cacheTag)
 : FileLoader(
 	toFile,
-	dcId,
 	size,
 	locationType,
 	toCache,
@@ -61,8 +60,6 @@ StreamedFileDownloader::StreamedFileDownloader(
 			savePart(std::move(part));
 		}
 	}, _lifetime);
-
-	requestParts();
 }
 
 StreamedFileDownloader::~StreamedFileDownloader() {
@@ -131,12 +128,8 @@ void StreamedFileDownloader::cancelRequests() {
 	_reader->cancelForDownloader(this);
 }
 
-bool StreamedFileDownloader::readyToRequest() const {
-	return false;
-}
-
-void StreamedFileDownloader::loadPart(int dcIndex) {
-	Unexpected("StreamedFileDownloader can't load parts.");
+void StreamedFileDownloader::startLoading() {
+	requestParts();
 }
 
 void StreamedFileDownloader::savePart(const LoadedPart &part) {
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.h b/Telegram/SourceFiles/storage/streamed_file_downloader.h
index 90aea8c09..43aa5e575 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.h
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.h
@@ -46,11 +46,10 @@ public:
 	QByteArray readLoadedPart(int offset);
 
 private:
+	void startLoading() override;
 	Cache::Key cacheKey() const override;
 	std::optional<MediaKey> fileLocationKey() const override;
 	void cancelRequests() override;
-	bool readyToRequest() const override;
-	void loadPart(int dcIndex) override;
 	void requestParts();
 	void requestPart();
 
diff --git a/Telegram/SourceFiles/ui/image/image_source.cpp b/Telegram/SourceFiles/ui/image/image_source.cpp
index f8246ec05..d5ae427c7 100644
--- a/Telegram/SourceFiles/ui/image/image_source.cpp
+++ b/Telegram/SourceFiles/ui/image/image_source.cpp
@@ -7,10 +7,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "ui/image/image_source.h"
 
-#include "storage/file_download.h"
+#include "storage/cache/storage_cache_database.h"
+#include "storage/file_download_mtproto.h"
+#include "storage/file_download_web.h"
 #include "data/data_session.h"
 #include "data/data_file_origin.h"
-#include "storage/cache/storage_cache_database.h"
 #include "history/history_item.h"
 #include "history/history.h"
 #include "main/main_session.h"
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index 6276efafc..14afd962a 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -685,6 +685,10 @@
 <(src_loc)/settings/settings_privacy_security.h
 <(src_loc)/storage/file_download.cpp
 <(src_loc)/storage/file_download.h
+<(src_loc)/storage/file_download_mtproto.cpp
+<(src_loc)/storage/file_download_mtproto.h
+<(src_loc)/storage/file_download_web.cpp
+<(src_loc)/storage/file_download_web.h
 <(src_loc)/storage/file_upload.cpp
 <(src_loc)/storage/file_upload.h
 <(src_loc)/storage/localimageloader.cpp

From ee94e7853383dc89f0c3cfa155a93605bcab99cb Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 5 Dec 2019 11:32:33 +0300
Subject: [PATCH 88/91] All mtproto downloads using DownloadMtprotoTask.

---
 Telegram/SourceFiles/apiwrap.cpp              |   8 +-
 Telegram/SourceFiles/apiwrap.h                |   4 +-
 Telegram/SourceFiles/boxes/confirm_box.cpp    |   1 +
 Telegram/SourceFiles/boxes/connection_box.cpp |   1 +
 .../SourceFiles/boxes/sticker_set_box.cpp     |   1 +
 Telegram/SourceFiles/boxes/stickers_box.cpp   |   1 +
 .../chat_helpers/field_autocomplete.cpp       |   1 +
 .../chat_helpers/gifs_list_widget.cpp         |   3 +-
 .../SourceFiles/chat_helpers/stickers.cpp     |   1 +
 .../chat_helpers/stickers_list_widget.cpp     |   1 +
 Telegram/SourceFiles/core/crash_reports.cpp   |   1 +
 Telegram/SourceFiles/data/data_document.cpp   |   1 -
 .../SourceFiles/data/data_media_types.cpp     |   1 +
 .../SourceFiles/history/history_widget.cpp    |   1 +
 .../view/media/history_view_document.cpp      |   1 +
 .../info/media/info_media_list_widget.cpp     |   4 +-
 .../inline_bot_layout_internal.cpp            |   1 +
 .../inline_bots/inline_bot_layout_item.cpp    |   1 +
 .../inline_bots/inline_bot_result.cpp         |   1 +
 .../inline_bots/inline_results_widget.cpp     |   3 +-
 Telegram/SourceFiles/main/main_session.cpp    |   3 +-
 Telegram/SourceFiles/main/main_session.h      |   6 +-
 Telegram/SourceFiles/mainwidget.cpp           |   1 +
 .../media_streaming_loader_mtproto.cpp        | 125 +--
 .../media_streaming_loader_mtproto.h          |  37 +-
 .../media/view/media_view_overlay_widget.cpp  |   1 +
 .../SourceFiles/overview/overview_layout.cpp  |   1 +
 .../SourceFiles/settings/settings_chat.cpp    |   1 +
 .../storage/download_manager_mtproto.cpp      | 714 ++++++++++++++++++
 .../storage/download_manager_mtproto.h        | 227 ++++++
 .../SourceFiles/storage/file_download.cpp     | 208 +----
 Telegram/SourceFiles/storage/file_download.h  | 108 +--
 .../storage/file_download_mtproto.cpp         | 495 +-----------
 .../storage/file_download_mtproto.h           |  96 +--
 .../SourceFiles/storage/file_download_web.cpp |  10 +-
 .../SourceFiles/storage/file_download_web.h   |   4 +-
 .../storage/streamed_file_downloader.cpp      |   8 +-
 .../storage/streamed_file_downloader.h        |   4 +-
 .../SourceFiles/ui/image/image_source.cpp     |   1 -
 .../window/notifications_manager_default.cpp  |   2 +-
 Telegram/gyp/telegram/sources.txt             |   2 +
 41 files changed, 1081 insertions(+), 1010 deletions(-)
 create mode 100644 Telegram/SourceFiles/storage/download_manager_mtproto.cpp
 create mode 100644 Telegram/SourceFiles/storage/download_manager_mtproto.h

diff --git a/Telegram/SourceFiles/apiwrap.cpp b/Telegram/SourceFiles/apiwrap.cpp
index b9272d3ec..ee33614e2 100644
--- a/Telegram/SourceFiles/apiwrap.cpp
+++ b/Telegram/SourceFiles/apiwrap.cpp
@@ -55,7 +55,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/emoji_config.h"
 #include "support/support_helper.h"
 #include "storage/localimageloader.h"
-#include "storage/file_download_mtproto.h"
+#include "storage/download_manager_mtproto.h"
 #include "storage/file_upload.h"
 #include "storage/storage_facade.h"
 #include "storage/storage_shared_media.h"
@@ -2973,12 +2973,12 @@ void ApiWrap::requestFileReference(
 
 void ApiWrap::refreshFileReference(
 		Data::FileOrigin origin,
-		not_null<mtpFileLoader*> loader,
+		not_null<Storage::DownloadMtprotoTask*> task,
 		int requestId,
 		const QByteArray &current) {
-	return refreshFileReference(origin, crl::guard(loader, [=](
+	return refreshFileReference(origin, crl::guard(task, [=](
 			const UpdatedFileReferences &data) {
-		loader->refreshFileReferenceFrom(data, requestId, current);
+		task->refreshFileReferenceFrom(data, requestId, current);
 	}));
 }
 
diff --git a/Telegram/SourceFiles/apiwrap.h b/Telegram/SourceFiles/apiwrap.h
index 0656d974b..7ac173793 100644
--- a/Telegram/SourceFiles/apiwrap.h
+++ b/Telegram/SourceFiles/apiwrap.h
@@ -20,7 +20,6 @@ struct MessageGroupId;
 struct SendingAlbum;
 enum class SendMediaType;
 struct FileLoadTo;
-class mtpFileLoader;
 
 namespace Main {
 class Session;
@@ -38,6 +37,7 @@ class Result;
 namespace Storage {
 enum class SharedMediaType : signed char;
 struct PreparedList;
+class DownloadMtprotoTask;
 } // namespace Storage
 
 namespace Dialogs {
@@ -201,7 +201,7 @@ public:
 		FileReferencesHandler &&handler);
 	void refreshFileReference(
 		Data::FileOrigin origin,
-		not_null<mtpFileLoader*> loader,
+		not_null<Storage::DownloadMtprotoTask*> task,
 		int requestId,
 		const QByteArray &current);
 
diff --git a/Telegram/SourceFiles/boxes/confirm_box.cpp b/Telegram/SourceFiles/boxes/confirm_box.cpp
index 402facdc0..c8b6efcd2 100644
--- a/Telegram/SourceFiles/boxes/confirm_box.cpp
+++ b/Telegram/SourceFiles/boxes/confirm_box.cpp
@@ -30,6 +30,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
+#include "data/data_file_origin.h"
 #include "base/unixtime.h"
 #include "main/main_session.h"
 #include "observer_peer.h"
diff --git a/Telegram/SourceFiles/boxes/connection_box.cpp b/Telegram/SourceFiles/boxes/connection_box.cpp
index f3a1a442c..b0912fd9b 100644
--- a/Telegram/SourceFiles/boxes/connection_box.cpp
+++ b/Telegram/SourceFiles/boxes/connection_box.cpp
@@ -14,6 +14,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/call_delayed.h"
 #include "core/application.h"
 #include "main/main_account.h"
+#include "mtproto/facade.h"
 #include "ui/widgets/checkbox.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/input_fields.h"
diff --git a/Telegram/SourceFiles/boxes/sticker_set_box.cpp b/Telegram/SourceFiles/boxes/sticker_set_box.cpp
index b5a496112..ca7130b2b 100644
--- a/Telegram/SourceFiles/boxes/sticker_set_box.cpp
+++ b/Telegram/SourceFiles/boxes/sticker_set_box.cpp
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "data/data_document.h"
 #include "data/data_session.h"
+#include "data/data_file_origin.h"
 #include "lang/lang_keys.h"
 #include "chat_helpers/stickers.h"
 #include "boxes/confirm_box.h"
diff --git a/Telegram/SourceFiles/boxes/stickers_box.cpp b/Telegram/SourceFiles/boxes/stickers_box.cpp
index 1be373e51..3f819d294 100644
--- a/Telegram/SourceFiles/boxes/stickers_box.cpp
+++ b/Telegram/SourceFiles/boxes/stickers_box.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_document.h"
 #include "data/data_session.h"
 #include "data/data_channel.h"
+#include "data/data_file_origin.h"
 #include "core/application.h"
 #include "lang/lang_keys.h"
 #include "mainwidget.h"
diff --git a/Telegram/SourceFiles/chat_helpers/field_autocomplete.cpp b/Telegram/SourceFiles/chat_helpers/field_autocomplete.cpp
index 07f6ba953..3f4186ddf 100644
--- a/Telegram/SourceFiles/chat_helpers/field_autocomplete.cpp
+++ b/Telegram/SourceFiles/chat_helpers/field_autocomplete.cpp
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_chat.h"
 #include "data/data_user.h"
 #include "data/data_peer_values.h"
+#include "data/data_file_origin.h"
 #include "mainwindow.h"
 #include "apiwrap.h"
 #include "storage/localstorage.h"
diff --git a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
index a99c0ecbe..5d9bce7e3 100644
--- a/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/gifs_list_widget.cpp
@@ -11,7 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_document.h"
 #include "data/data_session.h"
 #include "data/data_user.h"
-#include "styles/style_chat_helpers.h"
+#include "data/data_file_origin.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/input_fields.h"
 #include "ui/effects/ripple_animation.h"
@@ -27,6 +27,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/view/history_view_cursor_state.h"
 #include "facades.h"
 #include "app.h"
+#include "styles/style_chat_helpers.h"
 
 #include <QtWidgets/QApplication>
 
diff --git a/Telegram/SourceFiles/chat_helpers/stickers.cpp b/Telegram/SourceFiles/chat_helpers/stickers.cpp
index 9b25b7fa0..22601e302 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers.cpp
+++ b/Telegram/SourceFiles/chat_helpers/stickers.cpp
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "data/data_document.h"
 #include "data/data_session.h"
+#include "data/data_file_origin.h"
 #include "boxes/stickers_box.h"
 #include "boxes/confirm_box.h"
 #include "lang/lang_keys.h"
diff --git a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
index 3a5afa29e..918da350d 100644
--- a/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
+++ b/Telegram/SourceFiles/chat_helpers/stickers_list_widget.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_document.h"
 #include "data/data_session.h"
 #include "data/data_channel.h"
+#include "data/data_file_origin.h"
 #include "ui/widgets/buttons.h"
 #include "ui/effects/animations.h"
 #include "ui/effects/ripple_animation.h"
diff --git a/Telegram/SourceFiles/core/crash_reports.cpp b/Telegram/SourceFiles/core/crash_reports.cpp
index f4b11d6ab..ccb2d2ce6 100644
--- a/Telegram/SourceFiles/core/crash_reports.cpp
+++ b/Telegram/SourceFiles/core/crash_reports.cpp
@@ -341,6 +341,7 @@ QString PlatformString() {
 }
 
 void StartCatching(not_null<Core::Launcher*> launcher) {
+	return; AssertIsDebug();
 #ifndef DESKTOP_APP_DISABLE_CRASH_REPORTS
 	ProcessAnnotations["Binary"] = cExeName().toUtf8().constData();
 	ProcessAnnotations["ApiId"] = QString::number(ApiId).toUtf8().constData();
diff --git a/Telegram/SourceFiles/data/data_document.cpp b/Telegram/SourceFiles/data/data_document.cpp
index f00a70b80..9149c6272 100644
--- a/Telegram/SourceFiles/data/data_document.cpp
+++ b/Telegram/SourceFiles/data/data_document.cpp
@@ -817,7 +817,6 @@ void DocumentData::destroyLoader() const {
 	if (cancelled()) {
 		loader->cancel();
 	}
-	loader->stop();
 }
 
 bool DocumentData::loading() const {
diff --git a/Telegram/SourceFiles/data/data_media_types.cpp b/Telegram/SourceFiles/data/data_media_types.cpp
index 167d1b4d0..2937c8b47 100644
--- a/Telegram/SourceFiles/data/data_media_types.cpp
+++ b/Telegram/SourceFiles/data/data_media_types.cpp
@@ -37,6 +37,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_web_page.h"
 #include "data/data_poll.h"
 #include "data/data_channel.h"
+#include "data/data_file_origin.h"
 #include "lang/lang_keys.h"
 #include "layout.h"
 #include "storage/file_upload.h"
diff --git a/Telegram/SourceFiles/history/history_widget.cpp b/Telegram/SourceFiles/history/history_widget.cpp
index cb61ad11f..4996804fa 100644
--- a/Telegram/SourceFiles/history/history_widget.cpp
+++ b/Telegram/SourceFiles/history/history_widget.cpp
@@ -40,6 +40,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_chat.h"
 #include "data/data_user.h"
 #include "data/data_scheduled_messages.h"
+#include "data/data_file_origin.h"
 #include "history/history.h"
 #include "history/history_item.h"
 #include "history/history_message.h"
diff --git a/Telegram/SourceFiles/history/view/media/history_view_document.cpp b/Telegram/SourceFiles/history/view/media/history_view_document.cpp
index 9343d66c8..46721cc34 100644
--- a/Telegram/SourceFiles/history/view/media/history_view_document.cpp
+++ b/Telegram/SourceFiles/history/view/media/history_view_document.cpp
@@ -21,6 +21,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_session.h"
 #include "data/data_document.h"
 #include "data/data_media_types.h"
+#include "data/data_file_origin.h"
 #include "app.h"
 #include "styles/style_history.h"
 
diff --git a/Telegram/SourceFiles/info/media/info_media_list_widget.cpp b/Telegram/SourceFiles/info/media/info_media_list_widget.cpp
index 8e63a2869..ca3aaa24b 100644
--- a/Telegram/SourceFiles/info/media/info_media_list_widget.cpp
+++ b/Telegram/SourceFiles/info/media/info_media_list_widget.cpp
@@ -13,13 +13,13 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_photo.h"
 #include "data/data_document.h"
 #include "data/data_session.h"
+#include "data/data_file_origin.h"
 #include "history/history_item.h"
 #include "history/history.h"
 #include "history/view/history_view_cursor_state.h"
 #include "window/themes/window_theme.h"
 #include "window/window_session_controller.h"
 #include "window/window_peer_menu.h"
-#include "storage/file_download.h"
 #include "ui/widgets/popup_menu.h"
 #include "ui/ui_utility.h"
 #include "ui/inactive_press.h"
@@ -574,7 +574,7 @@ void ListWidget::start() {
 		}
 	}, lifetime());
 	ObservableViewer(
-		session().downloader().taskFinished()
+		session().downloaderTaskFinished()
 	) | rpl::start_with_next([this] { update(); }, lifetime());
 	session().data().itemLayoutChanged(
 	) | rpl::start_with_next([this](auto item) {
diff --git a/Telegram/SourceFiles/inline_bots/inline_bot_layout_internal.cpp b/Telegram/SourceFiles/inline_bots/inline_bot_layout_internal.cpp
index 24a485763..960ec1078 100644
--- a/Telegram/SourceFiles/inline_bots/inline_bot_layout_internal.cpp
+++ b/Telegram/SourceFiles/inline_bots/inline_bot_layout_internal.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_photo.h"
 #include "data/data_document.h"
 #include "data/data_session.h"
+#include "data/data_file_origin.h"
 #include "styles/style_overview.h"
 #include "styles/style_history.h"
 #include "styles/style_chat_helpers.h"
diff --git a/Telegram/SourceFiles/inline_bots/inline_bot_layout_item.cpp b/Telegram/SourceFiles/inline_bots/inline_bot_layout_item.cpp
index 4823a58f1..679cf6bf9 100644
--- a/Telegram/SourceFiles/inline_bots/inline_bot_layout_item.cpp
+++ b/Telegram/SourceFiles/inline_bots/inline_bot_layout_item.cpp
@@ -10,6 +10,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_photo.h"
 #include "data/data_document.h"
 #include "data/data_peer.h"
+#include "data/data_file_origin.h"
 #include "core/click_handler_types.h"
 #include "inline_bots/inline_bot_result.h"
 #include "inline_bots/inline_bot_layout_internal.h"
diff --git a/Telegram/SourceFiles/inline_bots/inline_bot_result.cpp b/Telegram/SourceFiles/inline_bots/inline_bot_result.cpp
index 0cacca7fa..f87d34734 100644
--- a/Telegram/SourceFiles/inline_bots/inline_bot_result.cpp
+++ b/Telegram/SourceFiles/inline_bots/inline_bot_result.cpp
@@ -11,6 +11,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_photo.h"
 #include "data/data_document.h"
 #include "data/data_session.h"
+#include "data/data_file_origin.h"
 #include "inline_bots/inline_bot_layout_item.h"
 #include "inline_bots/inline_bot_send_data.h"
 #include "storage/file_download.h"
diff --git a/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp b/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
index 03fdf601c..78c2dcb19 100644
--- a/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
+++ b/Telegram/SourceFiles/inline_bots/inline_results_widget.cpp
@@ -12,7 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_user.h"
 #include "data/data_session.h"
-#include "styles/style_chat_helpers.h"
+#include "data/data_file_origin.h"
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/shadow.h"
 #include "ui/effects/ripple_animation.h"
@@ -34,6 +34,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "history/view/history_view_cursor_state.h"
 #include "facades.h"
 #include "app.h"
+#include "styles/style_chat_helpers.h"
 
 #include <QtWidgets/QApplication>
 
diff --git a/Telegram/SourceFiles/main/main_session.cpp b/Telegram/SourceFiles/main/main_session.cpp
index b41225227..b88690b84 100644
--- a/Telegram/SourceFiles/main/main_session.cpp
+++ b/Telegram/SourceFiles/main/main_session.cpp
@@ -13,6 +13,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "main/main_account.h"
 #include "chat_helpers/stickers_emoji_pack.h"
 #include "storage/file_download.h"
+#include "storage/download_manager_mtproto.h"
 #include "storage/file_upload.h"
 #include "storage/localstorage.h"
 #include "storage/storage_facade.h"
@@ -44,7 +45,7 @@ Session::Session(
 , _autoLockTimer([=] { checkAutoLock(); })
 , _api(std::make_unique<ApiWrap>(this))
 , _calls(std::make_unique<Calls::Instance>(this))
-, _downloader(std::make_unique<Storage::DownloadManager>(_api.get()))
+, _downloader(std::make_unique<Storage::DownloadManagerMtproto>(_api.get()))
 , _uploader(std::make_unique<Storage::Uploader>(_api.get()))
 , _storage(std::make_unique<Storage::Facade>())
 , _notifications(std::make_unique<Window::Notifications::System>(this))
diff --git a/Telegram/SourceFiles/main/main_session.h b/Telegram/SourceFiles/main/main_session.h
index 117744c92..a215ee815 100644
--- a/Telegram/SourceFiles/main/main_session.h
+++ b/Telegram/SourceFiles/main/main_session.h
@@ -29,7 +29,7 @@ class Session;
 } // namespace Data
 
 namespace Storage {
-class DownloadManager;
+class DownloadManagerMtproto;
 class Uploader;
 class Facade;
 } // namespace Storage
@@ -80,7 +80,7 @@ public:
 	}
 	bool validateSelf(const MTPUser &user);
 
-	[[nodiscard]] Storage::DownloadManager &downloader() {
+	[[nodiscard]] Storage::DownloadManagerMtproto &downloader() {
 		return *_downloader;
 	}
 	[[nodiscard]] Storage::Uploader &uploader() {
@@ -145,7 +145,7 @@ private:
 
 	const std::unique_ptr<ApiWrap> _api;
 	const std::unique_ptr<Calls::Instance> _calls;
-	const std::unique_ptr<Storage::DownloadManager> _downloader;
+	const std::unique_ptr<Storage::DownloadManagerMtproto> _downloader;
 	const std::unique_ptr<Storage::Uploader> _uploader;
 	const std::unique_ptr<Storage::Facade> _storage;
 	const std::unique_ptr<Window::Notifications::System> _notifications;
diff --git a/Telegram/SourceFiles/mainwidget.cpp b/Telegram/SourceFiles/mainwidget.cpp
index 58e007dbb..3209c76ee 100644
--- a/Telegram/SourceFiles/mainwidget.cpp
+++ b/Telegram/SourceFiles/mainwidget.cpp
@@ -23,6 +23,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_chat.h"
 #include "data/data_user.h"
 #include "data/data_scheduled_messages.h"
+#include "data/data_file_origin.h"
 #include "api/api_text_entities.h"
 #include "ui/special_buttons.h"
 #include "ui/widgets/buttons.h"
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
index 13ac04549..e54f73520 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.cpp
@@ -21,27 +21,17 @@ constexpr auto kMaxConcurrentRequests = 4;
 } // namespace
 
 LoaderMtproto::LoaderMtproto(
-	not_null<Storage::DownloadManager*> owner,
+	not_null<Storage::DownloadManagerMtproto*> owner,
 	const StorageFileLocation &location,
 	int size,
 	Data::FileOrigin origin)
-: _owner(owner)
-, _location(location)
-, _dcId(location.dcId())
+: DownloadMtprotoTask(owner, location, origin)
 , _size(size)
-, _origin(origin)
-, _api(_owner->api().instance()) {
-}
-
-LoaderMtproto::~LoaderMtproto() {
-	for (const auto [index, amount] : _amountByDcIndex) {
-		changeRequestedAmount(index, -amount);
-	}
-	_owner->remove(this);
+, _api(api().instance()) {
 }
 
 std::optional<Storage::Cache::Key> LoaderMtproto::baseCacheKey() const {
-	return _location.bigFileBaseCacheKey();
+	return location().data.get<StorageFileLocation>().bigFileBaseCacheKey();
 }
 
 int LoaderMtproto::size() const {
@@ -58,22 +48,19 @@ void LoaderMtproto::load(int offset) {
 				return;
 			}
 		}
-		if (_requests.contains(offset)) {
+		if (haveSentRequestForOffset(offset)) {
 			return;
 		} else if (_requested.add(offset)) {
-			_owner->enqueue(this); // #TODO download priority
+			addToQueue(); // #TODO download priority
 		}
 	});
 }
 
 void LoaderMtproto::stop() {
 	crl::on_main(this, [=] {
-		ranges::for_each(
-			base::take(_requests),
-			_api.requestCanceller(),
-			&base::flat_map<int, mtpRequestId>::value_type::second);
+		cancelAllRequests();
 		_requested.clear();
-		_owner->remove(this);
+		removeFromQueue();
 	});
 }
 
@@ -84,9 +71,9 @@ void LoaderMtproto::cancel(int offset) {
 }
 
 void LoaderMtproto::cancelForOffset(int offset) {
-	if (const auto requestId = _requests.take(offset)) {
-		_api.request(*requestId).cancel();
-		_owner->enqueue(this);
+	if (haveSentRequestForOffset(offset)) {
+		cancelRequestForOffset(offset);
+		addToQueue(); // #TODO download priority
 	} else {
 		_requested.remove(offset);
 	}
@@ -107,100 +94,26 @@ void LoaderMtproto::increasePriority() {
 	});
 }
 
-void LoaderMtproto::changeRequestedAmount(int index, int amount) {
-	_owner->requestedAmountIncrement(_dcId, index, amount);
-	_amountByDcIndex[index] += amount;
-}
-
-MTP::DcId LoaderMtproto::dcId() const {
-	return _dcId;
-}
-
 bool LoaderMtproto::readyToRequest() const {
 	return !_requested.empty();
 }
 
-void LoaderMtproto::loadPart(int dcIndex) {
-	const auto offset = _requested.take().value_or(-1);
-	if (offset < 0) {
-		return;
-	}
+int LoaderMtproto::takeNextRequestOffset() {
+	const auto offset = _requested.take();
 
-	changeRequestedAmount(dcIndex, kPartSize);
-
-	const auto usedFileReference = _location.fileReference();
-	const auto id = _api.request(MTPupload_GetFile(
-		MTP_flags(0),
-		_location.tl(Auth().userId()),
-		MTP_int(offset),
-		MTP_int(kPartSize)
-	)).done([=](const MTPupload_File &result) {
-		changeRequestedAmount(dcIndex, -kPartSize);
-		requestDone(offset, result);
-	}).fail([=](const RPCError &error) {
-		changeRequestedAmount(dcIndex, -kPartSize);
-		requestFailed(offset, error, usedFileReference);
-	}).toDC(
-		MTP::downloadDcId(_dcId, dcIndex)
-	).send();
-	_requests.emplace(offset, id);
+	Ensures(offset.has_value());
+	return *offset;
 }
 
-void LoaderMtproto::requestDone(int offset, const MTPupload_File &result) {
-	result.match([&](const MTPDupload_file &data) {
-		_requests.erase(offset);
-		_owner->enqueue(this);
-		_parts.fire({ offset, data.vbytes().v });
-	}, [&](const MTPDupload_fileCdnRedirect &data) {
-		changeCdnParams(
-			offset,
-			data.vdc_id().v,
-			data.vfile_token().v,
-			data.vencryption_key().v,
-			data.vencryption_iv().v,
-			data.vfile_hashes().v);
-	});
+bool LoaderMtproto::feedPart(int offset, const QByteArray &bytes) {
+	_parts.fire({ offset, bytes });
+	return true;
 }
 
-void LoaderMtproto::changeCdnParams(
-		int offset,
-		MTP::DcId dcId,
-		const QByteArray &token,
-		const QByteArray &encryptionKey,
-		const QByteArray &encryptionIV,
-		const QVector<MTPFileHash> &hashes) {
-	// #TODO streaming later cdn
+void LoaderMtproto::cancelOnFail() {
 	_parts.fire({ LoadedPart::kFailedOffset });
 }
 
-void LoaderMtproto::requestFailed(
-		int offset,
-		const RPCError &error,
-		const QByteArray &usedFileReference) {
-	const auto &type = error.type();
-	const auto fail = [=] {
-		_parts.fire({ LoadedPart::kFailedOffset });
-	};
-	if (error.code() != 400 || !type.startsWith(qstr("FILE_REFERENCE_"))) {
-		return fail();
-	}
-	const auto callback = [=](const Data::UpdatedFileReferences &updated) {
-		_location.refreshFileReference(updated);
-		if (_location.fileReference() == usedFileReference) {
-			fail();
-		} else if (!_requests.take(offset)) {
-			// Request with such offset was already cancelled.
-			return;
-		} else {
-			_requested.add(offset);
-			_owner->enqueue(this);
-		}
-	};
-	_owner->api().refreshFileReference(
-		_origin,
-		crl::guard(this, callback));
-}
-
 rpl::producer<LoadedPart> LoaderMtproto::parts() const {
 	return _parts.events();
 }
diff --git a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
index a9a229403..380890d42 100644
--- a/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
+++ b/Telegram/SourceFiles/media/streaming/media_streaming_loader_mtproto.h
@@ -10,22 +10,18 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "media/streaming/media_streaming_loader.h"
 #include "mtproto/sender.h"
 #include "data/data_file_origin.h"
-#include "storage/file_download.h"
+#include "storage/download_manager_mtproto.h"
 
 namespace Media {
 namespace Streaming {
 
-class LoaderMtproto
-	: public Loader
-	, public base::has_weak_ptr
-	, public Storage::Downloader {
+class LoaderMtproto : public Loader, public Storage::DownloadMtprotoTask {
 public:
 	LoaderMtproto(
-		not_null<Storage::DownloadManager*> owner,
+		not_null<Storage::DownloadManagerMtproto*> owner,
 		const StorageFileLocation &location,
 		int size,
 		Data::FileOrigin origin);
-	~LoaderMtproto();
 
 	[[nodiscard]] auto baseCacheKey() const
 	-> std::optional<Storage::Cache::Key> override;
@@ -44,39 +40,18 @@ public:
 	void clearAttachedDownloader() override;
 
 private:
-	MTP::DcId dcId() const override;
 	bool readyToRequest() const override;
-	void loadPart(int dcIndex) override;
+	int takeNextRequestOffset() override;
+	bool feedPart(int offset, const QByteArray &bytes) override;
+	void cancelOnFail() override;
 
-	void requestDone(int offset, const MTPupload_File &result);
-	void requestFailed(
-		int offset,
-		const RPCError &error,
-		const QByteArray &usedFileReference);
-	void changeCdnParams(
-		int offset,
-		MTP::DcId dcId,
-		const QByteArray &token,
-		const QByteArray &encryptionKey,
-		const QByteArray &encryptionIV,
-		const QVector<MTPFileHash> &hashes);
 	void cancelForOffset(int offset);
-	void changeRequestedAmount(int index, int amount);
-
-	const not_null<Storage::DownloadManager*> _owner;
-
-	// _location can be changed with an updated file_reference.
-	StorageFileLocation _location;
-	MTP::DcId _dcId = 0;
 
 	const int _size = 0;
-	const Data::FileOrigin _origin;
 
 	MTP::Sender _api;
 
 	PriorityQueue _requested;
-	base::flat_map<int, mtpRequestId> _requests;
-	base::flat_map<int, int> _amountByDcIndex;
 	rpl::event_stream<LoadedPart> _parts;
 
 	Storage::StreamedFileDownloader *_downloader = nullptr;
diff --git a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
index 56f93e9b4..a168f0082 100644
--- a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
+++ b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
@@ -36,6 +36,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_channel.h"
 #include "data/data_chat.h"
 #include "data/data_user.h"
+#include "data/data_file_origin.h"
 #include "window/themes/window_theme_preview.h"
 #include "window/window_peer_menu.h"
 #include "window/window_session_controller.h"
diff --git a/Telegram/SourceFiles/overview/overview_layout.cpp b/Telegram/SourceFiles/overview/overview_layout.cpp
index cf08a6048..575a47108 100644
--- a/Telegram/SourceFiles/overview/overview_layout.cpp
+++ b/Telegram/SourceFiles/overview/overview_layout.cpp
@@ -12,6 +12,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "data/data_web_page.h"
 #include "data/data_media_types.h"
 #include "data/data_peer.h"
+#include "data/data_file_origin.h"
 #include "styles/style_overview.h"
 #include "styles/style_history.h"
 #include "core/file_utilities.h"
diff --git a/Telegram/SourceFiles/settings/settings_chat.cpp b/Telegram/SourceFiles/settings/settings_chat.cpp
index d72ceb81b..3477ca29f 100644
--- a/Telegram/SourceFiles/settings/settings_chat.cpp
+++ b/Telegram/SourceFiles/settings/settings_chat.cpp
@@ -40,6 +40,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/application.h"
 #include "data/data_session.h"
 #include "data/data_cloud_themes.h"
+#include "data/data_file_origin.h"
 #include "chat_helpers/emoji_sets_manager.h"
 #include "base/platform/base_platform_info.h"
 #include "base/call_delayed.h"
diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
new file mode 100644
index 000000000..92c0d828f
--- /dev/null
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
@@ -0,0 +1,714 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "storage/download_manager_mtproto.h"
+
+#include "mtproto/facade.h"
+#include "mtproto/mtproto_auth_key.h"
+#include "mtproto/mtproto_rpc_sender.h"
+#include "main/main_session.h"
+#include "apiwrap.h"
+#include "base/openssl_help.h"
+
+namespace Storage {
+namespace {
+
+// How much time without download causes additional session kill.
+constexpr auto kKillSessionTimeout = 15 * crl::time(1000);
+
+// Max 16 file parts downloaded at the same time, 128 KB each.
+constexpr auto kMaxFileQueries = 16;
+
+constexpr auto kMaxWaitedInConnection = 512 * 1024;
+
+// Max 8 http[s] files downloaded at the same time.
+constexpr auto kMaxWebFileQueries = 8;
+
+constexpr auto kStartSessionsCount = 1;
+constexpr auto kMaxSessionsCount = 8;
+constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
+
+} // namespace
+
+void DownloadManagerMtproto::Queue::enqueue(not_null<Task*> task) {
+	const auto i = ranges::find(_tasks, task);
+	if (i != end(_tasks)) {
+		return;
+	}
+	_tasks.push_back(task);
+	_previousGeneration.erase(
+		ranges::remove(_previousGeneration, task),
+		end(_previousGeneration));
+}
+
+void DownloadManagerMtproto::Queue::remove(not_null<Task*> task) {
+	_tasks.erase(ranges::remove(_tasks, task), end(_tasks));
+	_previousGeneration.erase(
+		ranges::remove(_previousGeneration, task),
+		end(_previousGeneration));
+}
+
+void DownloadManagerMtproto::Queue::resetGeneration() {
+	if (!_previousGeneration.empty()) {
+		_tasks.reserve(_tasks.size() + _previousGeneration.size());
+		std::copy(
+			begin(_previousGeneration),
+			end(_previousGeneration),
+			std::back_inserter(_tasks));
+		_previousGeneration.clear();
+	}
+	std::swap(_tasks, _previousGeneration);
+}
+
+bool DownloadManagerMtproto::Queue::empty() const {
+	return _tasks.empty() && _previousGeneration.empty();
+}
+
+auto DownloadManagerMtproto::Queue::nextTask() const -> Task* {
+	auto &&all = ranges::view::concat(_tasks, _previousGeneration);
+	const auto i = ranges::find(all, true, &Task::readyToRequest);
+	return (i != all.end()) ? i->get() : nullptr;
+}
+
+DownloadManagerMtproto::DownloadManagerMtproto(not_null<ApiWrap*> api)
+: _api(api)
+, _resetGenerationTimer([=] { resetGeneration(); })
+, _killDownloadSessionsTimer([=] { killDownloadSessions(); }) {
+}
+
+DownloadManagerMtproto::~DownloadManagerMtproto() {
+	killDownloadSessions();
+}
+
+void DownloadManagerMtproto::enqueue(not_null<Task*> task) {
+	const auto dcId = task->dcId();
+	auto &queue = _queues[dcId];
+	queue.enqueue(task);
+	if (!_resetGenerationTimer.isActive()) {
+		_resetGenerationTimer.callOnce(kResetDownloadPrioritiesTimeout);
+	}
+	checkSendNext(dcId, queue);
+}
+
+void DownloadManagerMtproto::remove(not_null<Task*> task) {
+	const auto dcId = task->dcId();
+	auto &queue = _queues[dcId];
+	queue.remove(task);
+	checkSendNext(dcId, queue);
+}
+
+void DownloadManagerMtproto::resetGeneration() {
+	_resetGenerationTimer.cancel();
+	for (auto &[dcId, queue] : _queues) {
+		queue.resetGeneration();
+	}
+}
+
+void DownloadManagerMtproto::checkSendNext() {
+	for (auto &[dcId, queue] : _queues) {
+		if (queue.empty()) {
+			continue;
+		}
+		checkSendNext(dcId, queue);
+	}
+}
+
+void DownloadManagerMtproto::checkSendNext(MTP::DcId dcId, Queue &queue) {
+	const auto bestIndex = [&] {
+		const auto i = _requestedBytesAmount.find(dcId);
+		if (i == end(_requestedBytesAmount)) {
+			_requestedBytesAmount[dcId].resize(kStartSessionsCount);
+			return 0;
+		}
+		const auto j = ranges::min_element(i->second);
+		const auto already = *j;
+		return (already + kDownloadPartSize <= kMaxWaitedInConnection)
+			? (j - begin(i->second))
+			: -1;
+	}();
+	if (bestIndex >= 0) {
+		if (const auto task = queue.nextTask()) {
+			task->loadPart(bestIndex);
+		}
+	}
+}
+
+void DownloadManagerMtproto::requestedAmountIncrement(
+		MTP::DcId dcId,
+		int index,
+		int amount) {
+	Expects(dcId != 0);
+
+	using namespace rpl::mappers;
+
+	auto it = _requestedBytesAmount.find(dcId);
+	if (it == _requestedBytesAmount.end()) {
+		it = _requestedBytesAmount.emplace(
+			dcId,
+			std::vector<int>(dcId ? kStartSessionsCount : 1, 0)
+		).first;
+	}
+	it->second[index] += amount;
+	if (amount > 0) {
+		killDownloadSessionsStop(dcId);
+	} else {
+		crl::on_main(this, [=] { checkSendNext(); });
+		if (ranges::find_if(it->second, _1 > 0) == end(it->second)) {
+			killDownloadSessionsStart(dcId);
+		}
+	}
+}
+
+int DownloadManagerMtproto::chooseDcIndexForRequest(MTP::DcId dcId) {
+	const auto i = _requestedBytesAmount.find(dcId);
+	return (i != end(_requestedBytesAmount))
+		? (ranges::min_element(i->second) - begin(i->second))
+		: 0;
+}
+
+void DownloadManagerMtproto::killDownloadSessionsStart(MTP::DcId dcId) {
+	if (!_killDownloadSessionTimes.contains(dcId)) {
+		_killDownloadSessionTimes.emplace(
+			dcId,
+			crl::now() + kKillSessionTimeout);
+	}
+	if (!_killDownloadSessionsTimer.isActive()) {
+		_killDownloadSessionsTimer.callOnce(kKillSessionTimeout + 5);
+	}
+}
+
+void DownloadManagerMtproto::killDownloadSessionsStop(MTP::DcId dcId) {
+	_killDownloadSessionTimes.erase(dcId);
+	if (_killDownloadSessionTimes.empty()
+		&& _killDownloadSessionsTimer.isActive()) {
+		_killDownloadSessionsTimer.cancel();
+	}
+}
+
+void DownloadManagerMtproto::killDownloadSessions() {
+	const auto now = crl::now();
+	auto left = kKillSessionTimeout;
+	for (auto i = _killDownloadSessionTimes.begin(); i != _killDownloadSessionTimes.end(); ) {
+		if (i->second <= now) {
+			const auto j = _requestedBytesAmount.find(i->first);
+			if (j != end(_requestedBytesAmount)) {
+				for (auto index = 0; index != int(j->second.size()); ++index) {
+					MTP::stopSession(MTP::downloadDcId(i->first, index));
+				}
+			}
+			i = _killDownloadSessionTimes.erase(i);
+		} else {
+			if (i->second - now < left) {
+				left = i->second - now;
+			}
+			++i;
+		}
+	}
+	if (!_killDownloadSessionTimes.empty()) {
+		_killDownloadSessionsTimer.callOnce(left);
+	}
+}
+
+DownloadMtprotoTask::DownloadMtprotoTask(
+	not_null<DownloadManagerMtproto*> owner,
+	const StorageFileLocation &location,
+	Data::FileOrigin origin)
+: _owner(owner)
+, _dcId(location.dcId())
+, _location({ location })
+, _origin(origin) {
+}
+
+DownloadMtprotoTask::DownloadMtprotoTask(
+	not_null<DownloadManagerMtproto*> owner,
+	MTP::DcId dcId,
+	const Location &location)
+: _owner(owner)
+, _dcId(dcId)
+, _location(location) {
+}
+
+DownloadMtprotoTask::~DownloadMtprotoTask() {
+	cancelAllRequests();
+	_owner->remove(this);
+}
+
+MTP::DcId DownloadMtprotoTask::dcId() const {
+	return _dcId;
+}
+
+Data::FileOrigin DownloadMtprotoTask::fileOrigin() const {
+	return _origin;
+}
+
+uint64 DownloadMtprotoTask::objectId() const {
+	if (const auto v = base::get_if<StorageFileLocation>(&_location.data)) {
+		return v->objectId();
+	}
+	return 0;
+}
+
+const DownloadMtprotoTask::Location &DownloadMtprotoTask::location() const {
+	return _location;
+}
+
+void DownloadMtprotoTask::refreshFileReferenceFrom(
+		const Data::UpdatedFileReferences &updates,
+		int requestId,
+		const QByteArray &current) {
+	if (const auto v = base::get_if<StorageFileLocation>(&_location.data)) {
+		v->refreshFileReference(updates);
+		if (v->fileReference() == current) {
+			cancelOnFail();
+			return;
+		}
+	} else {
+		cancelOnFail();
+		return;
+	}
+	makeRequest(finishSentRequest(requestId));
+}
+
+void DownloadMtprotoTask::loadPart(int dcIndex) {
+	makeRequest({ takeNextRequestOffset(), dcIndex });
+}
+
+mtpRequestId DownloadMtprotoTask::sendRequest(const RequestData &requestData) {
+	const auto offset = requestData.offset;
+	const auto limit = Storage::kDownloadPartSize;
+	const auto shiftedDcId = MTP::downloadDcId(
+		_cdnDcId ? _cdnDcId : dcId(),
+		requestData.dcIndex);
+	if (_cdnDcId) {
+		return api().request(MTPupload_GetCdnFile(
+			MTP_bytes(_cdnToken),
+			MTP_int(offset),
+			MTP_int(limit)
+		)).done([=](const MTPupload_CdnFile &result, mtpRequestId id) {
+			cdnPartLoaded(result, id);
+		}).fail([=](const RPCError &error, mtpRequestId id) {
+			cdnPartFailed(error, id);
+		}).toDC(shiftedDcId).send();
+	}
+	return _location.data.match([&](const WebFileLocation &location) {
+		return api().request(MTPupload_GetWebFile(
+			MTP_inputWebFileLocation(
+				MTP_bytes(location.url()),
+				MTP_long(location.accessHash())),
+			MTP_int(offset),
+			MTP_int(limit)
+		)).done([=](const MTPupload_WebFile &result, mtpRequestId id) {
+			webPartLoaded(result, id);
+		}).fail([=](const RPCError &error, mtpRequestId id) {
+			partFailed(error, id);
+		}).toDC(shiftedDcId).send();
+	}, [&](const GeoPointLocation &location) {
+		return api().request(MTPupload_GetWebFile(
+			MTP_inputWebFileGeoPointLocation(
+				MTP_inputGeoPoint(
+					MTP_double(location.lat),
+					MTP_double(location.lon)),
+				MTP_long(location.access),
+				MTP_int(location.width),
+				MTP_int(location.height),
+				MTP_int(location.zoom),
+				MTP_int(location.scale)),
+			MTP_int(offset),
+			MTP_int(limit)
+		)).done([=](const MTPupload_WebFile &result, mtpRequestId id) {
+			webPartLoaded(result, id);
+		}).fail([=](const RPCError &error, mtpRequestId id) {
+			partFailed(error, id);
+		}).toDC(shiftedDcId).send();
+	}, [&](const StorageFileLocation &location) {
+		const auto reference = location.fileReference();
+		return api().request(MTPupload_GetFile(
+			MTP_flags(0),
+			location.tl(api().session().userId()),
+			MTP_int(offset),
+			MTP_int(limit)
+		)).done([=](const MTPupload_File &result, mtpRequestId id) {
+			normalPartLoaded(result, id);
+		}).fail([=](const RPCError &error, mtpRequestId id) {
+			normalPartFailed(reference, error, id);
+		}).toDC(shiftedDcId).send();
+	});
+}
+
+bool DownloadMtprotoTask::setWebFileSizeHook(int size) {
+	return true;
+}
+
+void DownloadMtprotoTask::makeRequest(const RequestData &requestData) {
+	placeSentRequest(sendRequest(requestData), requestData);
+}
+
+void DownloadMtprotoTask::requestMoreCdnFileHashes() {
+	if (_cdnHashesRequestId || _cdnUncheckedParts.empty()) {
+		return;
+	}
+
+	const auto requestData = _cdnUncheckedParts.cbegin()->first;
+	const auto shiftedDcId = MTP::downloadDcId(
+		dcId(),
+		requestData.dcIndex);
+	_cdnHashesRequestId = api().request(MTPupload_GetCdnFileHashes(
+		MTP_bytes(_cdnToken),
+		MTP_int(requestData.offset)
+	)).done([=](const MTPVector<MTPFileHash> &result, mtpRequestId id) {
+		getCdnFileHashesDone(result, id);
+	}).fail([=](const RPCError &error, mtpRequestId id) {
+		cdnPartFailed(error, id);
+	}).toDC(shiftedDcId).send();
+	placeSentRequest(_cdnHashesRequestId, requestData);
+}
+
+void DownloadMtprotoTask::normalPartLoaded(
+		const MTPupload_File &result,
+		mtpRequestId requestId) {
+	const auto requestData = finishSentRequest(requestId);
+	result.match([&](const MTPDupload_fileCdnRedirect &data) {
+		switchToCDN(requestData, data);
+	}, [&](const MTPDupload_file &data) {
+		partLoaded(requestData.offset, data.vbytes().v);
+	});
+}
+
+void DownloadMtprotoTask::webPartLoaded(
+		const MTPupload_WebFile &result,
+		mtpRequestId requestId) {
+	result.match([&](const MTPDupload_webFile &data) {
+		const auto requestData = finishSentRequest(requestId);
+		if (setWebFileSizeHook(data.vsize().v)) {
+			partLoaded(requestData.offset, data.vbytes().v);
+		}
+	});
+}
+
+void DownloadMtprotoTask::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId) {
+	const auto requestData = finishSentRequest(requestId);
+	result.match([&](const MTPDupload_cdnFileReuploadNeeded &data) {
+		const auto shiftedDcId = MTP::downloadDcId(
+			dcId(),
+			requestData.dcIndex);
+		const auto requestId = api().request(MTPupload_ReuploadCdnFile(
+			MTP_bytes(_cdnToken),
+			data.vrequest_token()
+		)).done([=](const MTPVector<MTPFileHash> &result, mtpRequestId id) {
+			reuploadDone(result, id);
+		}).fail([=](const RPCError &error, mtpRequestId id) {
+			cdnPartFailed(error, id);
+		}).toDC(shiftedDcId).send();
+		placeSentRequest(requestId, requestData);
+	}, [&](const MTPDupload_cdnFile &data) {
+		auto key = bytes::make_span(_cdnEncryptionKey);
+		auto iv = bytes::make_span(_cdnEncryptionIV);
+		Expects(key.size() == MTP::CTRState::KeySize);
+		Expects(iv.size() == MTP::CTRState::IvecSize);
+
+		auto state = MTP::CTRState();
+		auto ivec = bytes::make_span(state.ivec);
+		std::copy(iv.begin(), iv.end(), ivec.begin());
+
+		auto counterOffset = static_cast<uint32>(requestData.offset) >> 4;
+		state.ivec[15] = static_cast<uchar>(counterOffset & 0xFF);
+		state.ivec[14] = static_cast<uchar>((counterOffset >> 8) & 0xFF);
+		state.ivec[13] = static_cast<uchar>((counterOffset >> 16) & 0xFF);
+		state.ivec[12] = static_cast<uchar>((counterOffset >> 24) & 0xFF);
+
+		auto decryptInPlace = data.vbytes().v;
+		auto buffer = bytes::make_detached_span(decryptInPlace);
+		MTP::aesCtrEncrypt(buffer, key.data(), &state);
+
+		switch (checkCdnFileHash(requestData.offset, buffer)) {
+		case CheckCdnHashResult::NoHash: {
+			_cdnUncheckedParts.emplace(requestData, decryptInPlace);
+			requestMoreCdnFileHashes();
+		} return;
+
+		case CheckCdnHashResult::Invalid: {
+			LOG(("API Error: Wrong cdnFileHash for offset %1."
+				).arg(requestData.offset));
+			cancelOnFail();
+		} return;
+
+		case CheckCdnHashResult::Good: {
+			partLoaded(requestData.offset, decryptInPlace);
+		} return;
+		}
+		Unexpected("Result of checkCdnFileHash()");
+	});
+}
+
+DownloadMtprotoTask::CheckCdnHashResult DownloadMtprotoTask::checkCdnFileHash(
+		int offset,
+		bytes::const_span buffer) {
+	const auto cdnFileHashIt = _cdnFileHashes.find(offset);
+	if (cdnFileHashIt == _cdnFileHashes.cend()) {
+		return CheckCdnHashResult::NoHash;
+	}
+	const auto realHash = openssl::Sha256(buffer);
+	const auto receivedHash = bytes::make_span(cdnFileHashIt->second.hash);
+	if (bytes::compare(realHash, receivedHash)) {
+		return CheckCdnHashResult::Invalid;
+	}
+	return CheckCdnHashResult::Good;
+}
+
+void DownloadMtprotoTask::reuploadDone(
+		const MTPVector<MTPFileHash> &result,
+		mtpRequestId requestId) {
+	const auto requestData = finishSentRequest(requestId);
+	addCdnHashes(result.v);
+	makeRequest(requestData);
+}
+
+void DownloadMtprotoTask::getCdnFileHashesDone(
+		const MTPVector<MTPFileHash> &result,
+		mtpRequestId requestId) {
+	Expects(_cdnHashesRequestId == requestId);
+
+	_cdnHashesRequestId = 0;
+
+	const auto requestData = finishSentRequest(requestId);
+	addCdnHashes(result.v);
+	auto someMoreChecked = false;
+	for (auto i = _cdnUncheckedParts.begin(); i != _cdnUncheckedParts.cend();) {
+		const auto uncheckedData = i->first;
+		const auto uncheckedBytes = bytes::make_span(i->second);
+
+		switch (checkCdnFileHash(uncheckedData.offset, uncheckedBytes)) {
+		case CheckCdnHashResult::NoHash: {
+			++i;
+		} break;
+
+		case CheckCdnHashResult::Invalid: {
+			LOG(("API Error: Wrong cdnFileHash for offset %1."
+				).arg(uncheckedData.offset));
+			cancelOnFail();
+			return;
+		} break;
+
+		case CheckCdnHashResult::Good: {
+			someMoreChecked = true;
+			const auto goodOffset = uncheckedData.offset;
+			const auto goodBytes = std::move(i->second);
+			const auto weak = base::make_weak(this);
+			i = _cdnUncheckedParts.erase(i);
+			if (!feedPart(goodOffset, goodBytes) || !weak) {
+				return;
+			}
+		} break;
+
+		default: Unexpected("Result of checkCdnFileHash()");
+		}
+	}
+	if (!someMoreChecked) {
+		LOG(("API Error: "
+			"Could not find cdnFileHash for offset %1 "
+			"after getCdnFileHashes request."
+			).arg(requestData.offset));
+		cancelOnFail();
+		return;
+	}
+	requestMoreCdnFileHashes();
+}
+
+void DownloadMtprotoTask::placeSentRequest(
+		mtpRequestId requestId,
+		const RequestData &requestData) {
+	_owner->requestedAmountIncrement(
+		dcId(),
+		requestData.dcIndex,
+		Storage::kDownloadPartSize);
+	const auto [i, ok1] = _sentRequests.emplace(requestId, requestData);
+	const auto [j, ok2] = _requestByOffset.emplace(
+		requestData.offset,
+		requestId);
+
+	Ensures(ok1 && ok2);
+}
+
+auto DownloadMtprotoTask::finishSentRequest(mtpRequestId requestId)
+-> RequestData {
+	auto it = _sentRequests.find(requestId);
+	Assert(it != _sentRequests.cend());
+
+	const auto result = it->second;
+	_owner->requestedAmountIncrement(
+		dcId(),
+		result.dcIndex,
+		-Storage::kDownloadPartSize);
+	_sentRequests.erase(it);
+	_requestByOffset.erase(result.offset);
+
+	return result;
+}
+
+bool DownloadMtprotoTask::haveSentRequests() const {
+	return !_sentRequests.empty() || !_cdnUncheckedParts.empty();
+}
+
+bool DownloadMtprotoTask::haveSentRequestForOffset(int offset) const {
+	return _requestByOffset.contains(offset)
+		|| _cdnUncheckedParts.contains({ offset, 0 });
+}
+
+void DownloadMtprotoTask::cancelAllRequests() {
+	while (!_sentRequests.empty()) {
+		cancelRequest(_sentRequests.begin()->first);
+	}
+	_cdnUncheckedParts.clear();
+}
+
+void DownloadMtprotoTask::cancelRequestForOffset(int offset) {
+	const auto i = _requestByOffset.find(offset);
+	if (i != end(_requestByOffset)) {
+		cancelRequest(i->second);
+	}
+	_cdnUncheckedParts.remove({ offset, 0 });
+}
+
+void DownloadMtprotoTask::cancelRequest(mtpRequestId requestId) {
+	api().request(requestId).cancel();
+	[[maybe_unused]] const auto data = finishSentRequest(requestId);
+}
+
+void DownloadMtprotoTask::addToQueue() {
+	_owner->enqueue(this);
+}
+
+void DownloadMtprotoTask::removeFromQueue() {
+	_owner->remove(this);
+}
+
+void DownloadMtprotoTask::partLoaded(
+		int offset,
+		const QByteArray &bytes) {
+	feedPart(offset, bytes);
+}
+
+bool DownloadMtprotoTask::normalPartFailed(
+		QByteArray fileReference,
+		const RPCError &error,
+		mtpRequestId requestId) {
+	if (MTP::isDefaultHandledError(error)) {
+		return false;
+	}
+	if (error.code() == 400
+		&& error.type().startsWith(qstr("FILE_REFERENCE_"))) {
+		api().refreshFileReference(
+			_origin,
+			this,
+			requestId,
+			fileReference);
+		return true;
+	}
+	return partFailed(error, requestId);
+}
+
+bool DownloadMtprotoTask::partFailed(
+		const RPCError &error,
+		mtpRequestId requestId) {
+	if (MTP::isDefaultHandledError(error)) {
+		return false;
+	}
+	cancelOnFail();
+	return true;
+}
+
+bool DownloadMtprotoTask::cdnPartFailed(
+		const RPCError &error,
+		mtpRequestId requestId) {
+	if (MTP::isDefaultHandledError(error)) {
+		return false;
+	}
+
+	if (requestId == _cdnHashesRequestId) {
+		_cdnHashesRequestId = 0;
+	}
+	if (error.type() == qstr("FILE_TOKEN_INVALID")
+		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
+		const auto requestData = finishSentRequest(requestId);
+		changeCDNParams(
+			requestData,
+			0,
+			QByteArray(),
+			QByteArray(),
+			QByteArray(),
+			QVector<MTPFileHash>());
+		return true;
+	}
+	return partFailed(error, requestId);
+}
+
+void DownloadMtprotoTask::switchToCDN(
+		const RequestData &requestData,
+		const MTPDupload_fileCdnRedirect &redirect) {
+	changeCDNParams(
+		requestData,
+		redirect.vdc_id().v,
+		redirect.vfile_token().v,
+		redirect.vencryption_key().v,
+		redirect.vencryption_iv().v,
+		redirect.vfile_hashes().v);
+}
+
+void DownloadMtprotoTask::addCdnHashes(
+		const QVector<MTPFileHash> &hashes) {
+	for (const auto &hash : hashes) {
+		hash.match([&](const MTPDfileHash &data) {
+			_cdnFileHashes.emplace(
+				data.voffset().v,
+				CdnFileHash{ data.vlimit().v, data.vhash().v });
+		});
+	}
+}
+
+void DownloadMtprotoTask::changeCDNParams(
+		const RequestData &requestData,
+		MTP::DcId dcId,
+		const QByteArray &token,
+		const QByteArray &encryptionKey,
+		const QByteArray &encryptionIV,
+		const QVector<MTPFileHash> &hashes) {
+	if (dcId != 0
+		&& (encryptionKey.size() != MTP::CTRState::KeySize
+			|| encryptionIV.size() != MTP::CTRState::IvecSize)) {
+		LOG(("Message Error: Wrong key (%1) / iv (%2) size in CDN params"
+			).arg(encryptionKey.size()
+			).arg(encryptionIV.size()));
+		cancelOnFail();
+		return;
+	}
+
+	auto resendAllRequests = (_cdnDcId != dcId
+		|| _cdnToken != token
+		|| _cdnEncryptionKey != encryptionKey
+		|| _cdnEncryptionIV != encryptionIV);
+	_cdnDcId = dcId;
+	_cdnToken = token;
+	_cdnEncryptionKey = encryptionKey;
+	_cdnEncryptionIV = encryptionIV;
+	addCdnHashes(hashes);
+
+	if (resendAllRequests && !_sentRequests.empty()) {
+		auto resendRequests = std::vector<RequestData>();
+		resendRequests.reserve(_sentRequests.size());
+		while (!_sentRequests.empty()) {
+			const auto requestId = _sentRequests.begin()->first;
+			api().request(requestId).cancel();
+			resendRequests.push_back(finishSentRequest(requestId));
+		}
+		for (const auto &requestData : resendRequests) {
+			makeRequest(requestData);
+		}
+	}
+	makeRequest(requestData);
+}
+
+} // namespace Storage
diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.h b/Telegram/SourceFiles/storage/download_manager_mtproto.h
new file mode 100644
index 000000000..7b78ad35e
--- /dev/null
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.h
@@ -0,0 +1,227 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#pragma once
+
+#include "data/data_file_origin.h"
+#include "base/timer.h"
+#include "base/weak_ptr.h"
+
+class ApiWrap;
+class RPCError;
+
+namespace Storage {
+
+// Different part sizes are not supported for now :(
+// Because we start downloading with some part size
+// and then we get a CDN-redirect where we support only
+// fixed part size download for hash checking.
+constexpr auto kDownloadPartSize = 128 * 1024;
+
+class DownloadMtprotoTask;
+
+class DownloadManagerMtproto final : public base::has_weak_ptr {
+public:
+	using Task = DownloadMtprotoTask;
+
+	explicit DownloadManagerMtproto(not_null<ApiWrap*> api);
+	~DownloadManagerMtproto();
+
+	[[nodiscard]] ApiWrap &api() const {
+		return *_api;
+	}
+
+	void enqueue(not_null<Task*> task);
+	void remove(not_null<Task*> task);
+
+	[[nodiscard]] base::Observable<void> &taskFinished() {
+		return _taskFinishedObservable;
+	}
+
+	void requestedAmountIncrement(MTP::DcId dcId, int index, int amount);
+	[[nodiscard]] int chooseDcIndexForRequest(MTP::DcId dcId);
+
+private:
+	class Queue final {
+	public:
+		void enqueue(not_null<Task*> task);
+		void remove(not_null<Task*> task);
+		void resetGeneration();
+		[[nodiscard]] bool empty() const;
+		[[nodiscard]] Task *nextTask() const;
+
+	private:
+		std::vector<not_null<Task*>> _tasks;
+		std::vector<not_null<Task*>> _previousGeneration;
+
+	};
+
+	void checkSendNext();
+	void checkSendNext(MTP::DcId dcId, Queue &queue);
+
+	void killDownloadSessionsStart(MTP::DcId dcId);
+	void killDownloadSessionsStop(MTP::DcId dcId);
+	void killDownloadSessions();
+
+	void resetGeneration();
+
+	const not_null<ApiWrap*> _api;
+
+	base::Observable<void> _taskFinishedObservable;
+
+	base::flat_map<MTP::DcId, std::vector<int>> _requestedBytesAmount;
+	base::Timer _resetGenerationTimer;
+
+	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
+	base::Timer _killDownloadSessionsTimer;
+
+	base::flat_map<MTP::DcId, Queue> _queues;
+
+};
+
+class DownloadMtprotoTask : public base::has_weak_ptr {
+public:
+	struct Location {
+		base::variant<
+			StorageFileLocation,
+			WebFileLocation,
+			GeoPointLocation> data;
+	};
+
+	DownloadMtprotoTask(
+		not_null<DownloadManagerMtproto*> owner,
+		const StorageFileLocation &location,
+		Data::FileOrigin origin);
+	DownloadMtprotoTask(
+		not_null<DownloadManagerMtproto*> owner,
+		MTP::DcId dcId,
+		const Location &location);
+	virtual ~DownloadMtprotoTask();
+
+	[[nodiscard]] MTP::DcId dcId() const;
+	[[nodiscard]] Data::FileOrigin fileOrigin() const;
+	[[nodiscard]] uint64 objectId() const;
+	[[nodiscard]] const Location &location() const;
+
+	[[nodiscard]] virtual bool readyToRequest() const = 0;
+	void loadPart(int dcIndex);
+
+	void refreshFileReferenceFrom(
+		const Data::UpdatedFileReferences &updates,
+		int requestId,
+		const QByteArray &current);
+
+protected:
+	[[nodiscard]] bool haveSentRequests() const;
+	[[nodiscard]] bool haveSentRequestForOffset(int offset) const;
+	void cancelAllRequests();
+	void cancelRequestForOffset(int offset);
+
+	void addToQueue();
+	void removeFromQueue();
+
+	[[nodiscard]] ApiWrap &api() const {
+		return _owner->api();
+	}
+
+private:
+	struct RequestData {
+		int offset = 0;
+		int dcIndex = 0;
+
+		inline bool operator<(const RequestData &other) const {
+			return offset < other.offset;
+		}
+	};
+	struct CdnFileHash {
+		CdnFileHash(int limit, QByteArray hash) : limit(limit), hash(hash) {
+		}
+		int limit = 0;
+		QByteArray hash;
+	};
+	enum class CheckCdnHashResult {
+		NoHash,
+		Invalid,
+		Good,
+	};
+
+	// Called only if readyToRequest() == true.
+	[[nodiscard]] virtual int takeNextRequestOffset() = 0;
+	virtual bool feedPart(int offset, const QByteArray &bytes) = 0;
+	virtual bool setWebFileSizeHook(int size);
+	virtual void cancelOnFail() = 0;
+
+	void cancelRequest(mtpRequestId requestId);
+	void makeRequest(const RequestData &requestData);
+	void normalPartLoaded(
+		const MTPupload_File &result,
+		mtpRequestId requestId);
+	void webPartLoaded(
+		const MTPupload_WebFile &result,
+		mtpRequestId requestId);
+	void cdnPartLoaded(
+		const MTPupload_CdnFile &result,
+		mtpRequestId requestId);
+	void reuploadDone(
+		const MTPVector<MTPFileHash> &result,
+		mtpRequestId requestId);
+	void requestMoreCdnFileHashes();
+	void getCdnFileHashesDone(
+		const MTPVector<MTPFileHash> &result,
+		mtpRequestId requestId);
+
+	void partLoaded(int offset, const QByteArray &bytes);
+
+	bool partFailed(const RPCError &error, mtpRequestId requestId);
+	bool normalPartFailed(
+		QByteArray fileReference,
+		const RPCError &error,
+		mtpRequestId requestId);
+	bool cdnPartFailed(const RPCError &error, mtpRequestId requestId);
+
+	[[nodiscard]] mtpRequestId sendRequest(const RequestData &requestData);
+	void placeSentRequest(
+		mtpRequestId requestId,
+		const RequestData &requestData);
+	[[nodiscard]] RequestData finishSentRequest(mtpRequestId requestId);
+	void switchToCDN(
+		const RequestData &requestData,
+		const MTPDupload_fileCdnRedirect &redirect);
+	void addCdnHashes(const QVector<MTPFileHash> &hashes);
+	void changeCDNParams(
+		const RequestData &requestData,
+		MTP::DcId dcId,
+		const QByteArray &token,
+		const QByteArray &encryptionKey,
+		const QByteArray &encryptionIV,
+		const QVector<MTPFileHash> &hashes);
+
+	[[nodiscard]] CheckCdnHashResult checkCdnFileHash(
+		int offset,
+		bytes::const_span buffer);
+
+	const not_null<DownloadManagerMtproto*> _owner;
+	const MTP::DcId _dcId = 0;
+
+	// _location can be changed with an updated file_reference.
+	Location _location;
+	const Data::FileOrigin _origin;
+
+	base::flat_map<mtpRequestId, RequestData> _sentRequests;
+	base::flat_map<int, mtpRequestId> _requestByOffset;
+
+	MTP::DcId _cdnDcId = 0;
+	QByteArray _cdnToken;
+	QByteArray _cdnEncryptionKey;
+	QByteArray _cdnEncryptionIV;
+	base::flat_map<int, CdnFileHash> _cdnFileHashes;
+	base::flat_map<RequestData, QByteArray> _cdnUncheckedParts;
+	mtpRequestId _cdnHashesRequestId = 0;
+
+};
+
+} // namespace Storage
diff --git a/Telegram/SourceFiles/storage/file_download.cpp b/Telegram/SourceFiles/storage/file_download.cpp
index 77f6f951a..72ddd262d 100644
--- a/Telegram/SourceFiles/storage/file_download.cpp
+++ b/Telegram/SourceFiles/storage/file_download.cpp
@@ -23,210 +23,6 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "facades.h"
 #include "app.h"
 
-namespace Storage {
-namespace {
-
-// How much time without download causes additional session kill.
-constexpr auto kKillSessionTimeout = 15 * crl::time(1000);
-
-// Max 16 file parts downloaded at the same time, 128 KB each.
-constexpr auto kMaxFileQueries = 16;
-
-constexpr auto kMaxWaitedInConnection = 512 * 1024;
-
-// Max 8 http[s] files downloaded at the same time.
-constexpr auto kMaxWebFileQueries = 8;
-
-constexpr auto kStartSessionsCount = 1;
-constexpr auto kMaxSessionsCount = 8;
-constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
-
-} // namespace
-
-void DownloadManager::Queue::enqueue(not_null<Downloader*> loader) {
-	const auto i = ranges::find(_loaders, loader);
-	if (i != end(_loaders)) {
-		return;
-	}
-	_loaders.push_back(loader);
-	_previousGeneration.erase(
-		ranges::remove(_previousGeneration, loader),
-		end(_previousGeneration));
-}
-
-void DownloadManager::Queue::remove(not_null<Downloader*> loader) {
-	_loaders.erase(ranges::remove(_loaders, loader), end(_loaders));
-	_previousGeneration.erase(
-		ranges::remove(_previousGeneration, loader),
-		end(_previousGeneration));
-}
-
-void DownloadManager::Queue::resetGeneration() {
-	if (!_previousGeneration.empty()) {
-		_loaders.reserve(_loaders.size() + _previousGeneration.size());
-		std::copy(
-			begin(_previousGeneration),
-			end(_previousGeneration),
-			std::back_inserter(_loaders));
-		_previousGeneration.clear();
-	}
-	std::swap(_loaders, _previousGeneration);
-}
-
-bool DownloadManager::Queue::empty() const {
-	return _loaders.empty() && _previousGeneration.empty();
-}
-
-Downloader *DownloadManager::Queue::nextLoader() const {
-	auto &&all = ranges::view::concat(_loaders, _previousGeneration);
-	const auto i = ranges::find(all, true, &Downloader::readyToRequest);
-	return (i != all.end()) ? i->get() : nullptr;
-}
-
-DownloadManager::DownloadManager(not_null<ApiWrap*> api)
-: _api(api)
-, _resetGenerationTimer([=] { resetGeneration(); })
-, _killDownloadSessionsTimer([=] { killDownloadSessions(); }) {
-}
-
-DownloadManager::~DownloadManager() {
-	killDownloadSessions();
-}
-
-void DownloadManager::enqueue(not_null<Downloader*> loader) {
-	const auto dcId = loader->dcId();
-	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).enqueue(loader);
-	if (!_resetGenerationTimer.isActive()) {
-		_resetGenerationTimer.callOnce(kResetDownloadPrioritiesTimeout);
-	}
-	checkSendNext();
-}
-
-void DownloadManager::remove(not_null<Downloader*> loader) {
-	const auto dcId = loader->dcId();
-	(dcId ? _mtprotoLoaders[dcId] : _webLoaders).remove(loader);
-	crl::on_main(&_api->session(), [=] { checkSendNext(); });
-}
-
-void DownloadManager::resetGeneration() {
-	_resetGenerationTimer.cancel();
-	for (auto &[dcId, queue] : _mtprotoLoaders) {
-		queue.resetGeneration();
-	}
-	_webLoaders.resetGeneration();
-}
-
-void DownloadManager::checkSendNext() {
-	for (auto &[dcId, queue] : _mtprotoLoaders) {
-		if (queue.empty()) {
-			continue;
-		}
-		const auto bestIndex = [&] {
-			const auto i = _requestedBytesAmount.find(dcId);
-			if (i == end(_requestedBytesAmount)) {
-				_requestedBytesAmount[dcId].resize(kStartSessionsCount);
-				return 0;
-			}
-			const auto j = ranges::min_element(i->second);
-			const auto already = *j;
-			return (already + kDownloadPartSize <= kMaxWaitedInConnection)
-				? (j - begin(i->second))
-				: -1;
-		}();
-		if (bestIndex < 0) {
-			continue;
-		}
-		if (const auto loader = queue.nextLoader()) {
-			loader->loadPart(bestIndex);
-		}
-	}
-	if (_requestedBytesAmount[0].empty()) {
-		_requestedBytesAmount[0] = std::vector<int>(1, 0);
-	}
-	if (_requestedBytesAmount[0][0] < kMaxWebFileQueries) {
-		if (const auto loader = _webLoaders.nextLoader()) {
-			loader->loadPart(0);
-		}
-	}
-}
-
-void DownloadManager::requestedAmountIncrement(
-		MTP::DcId dcId,
-		int index,
-		int amount) {
-	using namespace rpl::mappers;
-
-	auto it = _requestedBytesAmount.find(dcId);
-	if (it == _requestedBytesAmount.end()) {
-		it = _requestedBytesAmount.emplace(
-			dcId,
-			std::vector<int>(dcId ? kStartSessionsCount : 1, 0)
-		).first;
-	}
-	it->second[index] += amount;
-	if (!dcId) {
-		return; // webLoaders.
-	}
-	if (amount > 0) {
-		killDownloadSessionsStop(dcId);
-	} else if (ranges::find_if(it->second, _1 > 0) == end(it->second)) {
-		killDownloadSessionsStart(dcId);
-		checkSendNext();
-	}
-}
-
-int DownloadManager::chooseDcIndexForRequest(MTP::DcId dcId) {
-	const auto i = _requestedBytesAmount.find(dcId);
-	return (i != end(_requestedBytesAmount))
-		? (ranges::min_element(i->second) - begin(i->second))
-		: 0;
-}
-
-void DownloadManager::killDownloadSessionsStart(MTP::DcId dcId) {
-	if (!_killDownloadSessionTimes.contains(dcId)) {
-		_killDownloadSessionTimes.emplace(
-			dcId,
-			crl::now() + kKillSessionTimeout);
-	}
-	if (!_killDownloadSessionsTimer.isActive()) {
-		_killDownloadSessionsTimer.callOnce(kKillSessionTimeout + 5);
-	}
-}
-
-void DownloadManager::killDownloadSessionsStop(MTP::DcId dcId) {
-	_killDownloadSessionTimes.erase(dcId);
-	if (_killDownloadSessionTimes.empty()
-		&& _killDownloadSessionsTimer.isActive()) {
-		_killDownloadSessionsTimer.cancel();
-	}
-}
-
-void DownloadManager::killDownloadSessions() {
-	const auto now = crl::now();
-	auto left = kKillSessionTimeout;
-	for (auto i = _killDownloadSessionTimes.begin(); i != _killDownloadSessionTimes.end(); ) {
-		if (i->second <= now) {
-			const auto j = _requestedBytesAmount.find(i->first);
-			if (j != end(_requestedBytesAmount)) {
-				for (auto index = 0; index != int(j->second.size()); ++index) {
-					MTP::stopSession(MTP::downloadDcId(i->first, index));
-				}
-			}
-			i = _killDownloadSessionTimes.erase(i);
-		} else {
-			if (i->second - now < left) {
-				left = i->second - now;
-			}
-			++i;
-		}
-	}
-	if (!_killDownloadSessionTimes.empty()) {
-		_killDownloadSessionsTimer.callOnce(left);
-	}
-}
-
-} // namespace Storage
-
 FileLoader::FileLoader(
 	const QString &toFile,
 	int32 size,
@@ -445,7 +241,9 @@ void FileLoader::cancel() {
 
 void FileLoader::cancel(bool fail) {
 	const auto started = (currentOffset() > 0);
-	cancelRequests();
+
+	cancelHook();
+
 	_cancelled = true;
 	_finished = true;
 	if (_fileIsOpen) {
diff --git a/Telegram/SourceFiles/storage/file_download.h b/Telegram/SourceFiles/storage/file_download.h
index 7f84ff820..d68b81352 100644
--- a/Telegram/SourceFiles/storage/file_download.h
+++ b/Telegram/SourceFiles/storage/file_download.h
@@ -10,12 +10,12 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "base/observer.h"
 #include "base/timer.h"
 #include "base/binary_guard.h"
-#include "data/data_file_origin.h"
-#include "mtproto/facade.h"
 
 #include <QtNetwork/QNetworkReply>
 
-class ApiWrap;
+namespace Data {
+struct FileOrigin;
+} // namespace Data
 
 namespace Main {
 class Session;
@@ -26,88 +26,22 @@ namespace Cache {
 struct Key;
 } // namespace Cache
 
+// 10 MB max file could be hold in memory
 // This value is used in local cache database settings!
-constexpr auto kMaxFileInMemory = 10 * 1024 * 1024; // 10 MB max file could be hold in memory
+constexpr auto kMaxFileInMemory = 10 * 1024 * 1024;
 
-constexpr auto kMaxVoiceInMemory = 2 * 1024 * 1024; // 2 MB audio is hold in memory and auto loaded
-constexpr auto kMaxStickerInMemory = 2 * 1024 * 1024; // 2 MB stickers hold in memory, auto loaded and displayed inline
+// 2 MB audio is hold in memory and auto loaded
+constexpr auto kMaxVoiceInMemory = 2 * 1024 * 1024;
+
+// 2 MB stickers hold in memory, auto loaded and displayed inline
+constexpr auto kMaxStickerInMemory = 2 * 1024 * 1024;
+
+// 10 MB GIF and mp4 animations held in memory while playing
 constexpr auto kMaxWallPaperInMemory = kMaxFileInMemory;
-constexpr auto kMaxAnimationInMemory = kMaxFileInMemory; // 10 MB gif and mp4 animations held in memory while playing
-constexpr auto kMaxWallPaperDimension = 4096; // 4096x4096 is max area.
+constexpr auto kMaxAnimationInMemory = kMaxFileInMemory;
 
-// Different part sizes are not supported for now :(
-// Because we start downloading with some part size
-// and then we get a cdn-redirect where we support only
-// fixed part size download for hash checking.
-constexpr auto kDownloadPartSize = 128 * 1024;
-
-class Downloader {
-public:
-	virtual ~Downloader() = default;
-
-	[[nodiscard]] virtual MTP::DcId dcId() const = 0;
-	[[nodiscard]] virtual bool readyToRequest() const = 0;
-	virtual void loadPart(int dcIndex) = 0;
-
-};
-
-class DownloadManager final : public base::has_weak_ptr {
-public:
-	explicit DownloadManager(not_null<ApiWrap*> api);
-	~DownloadManager();
-
-	[[nodiscard]] ApiWrap &api() const {
-		return *_api;
-	}
-
-	void enqueue(not_null<Downloader*> loader);
-	void remove(not_null<Downloader*> loader);
-
-	[[nodiscard]] base::Observable<void> &taskFinished() {
-		return _taskFinishedObservable;
-	}
-
-	// dcId == 0 is for web requests.
-	void requestedAmountIncrement(MTP::DcId dcId, int index, int amount);
-	[[nodiscard]] int chooseDcIndexForRequest(MTP::DcId dcId);
-
-private:
-	class Queue final {
-	public:
-		void enqueue(not_null<Downloader*> loader);
-		void remove(not_null<Downloader*> loader);
-		void resetGeneration();
-		[[nodiscard]] bool empty() const;
-		[[nodiscard]] Downloader *nextLoader() const;
-
-	private:
-		std::vector<not_null<Downloader*>> _loaders;
-		std::vector<not_null<Downloader*>> _previousGeneration;
-
-	};
-
-	void checkSendNext();
-
-	void killDownloadSessionsStart(MTP::DcId dcId);
-	void killDownloadSessionsStop(MTP::DcId dcId);
-	void killDownloadSessions();
-
-	void resetGeneration();
-
-	const not_null<ApiWrap*> _api;
-
-	base::Observable<void> _taskFinishedObservable;
-
-	base::flat_map<MTP::DcId, std::vector<int>> _requestedBytesAmount;
-	base::Timer _resetGenerationTimer;
-
-	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
-	base::Timer _killDownloadSessionsTimer;
-
-	base::flat_map<MTP::DcId, Queue> _mtprotoLoaders;
-	Queue _webLoaders;
-
-};
+// 4096x4096 is max area.
+constexpr auto kMaxWallPaperDimension = 4096;
 
 } // namespace Storage
 
@@ -132,8 +66,9 @@ public:
 		LoadFromCloudSetting fromCloud,
 		bool autoLoading,
 		uint8 cacheTag);
+	virtual ~FileLoader();
 
-	Main::Session &session() const;
+	[[nodiscard]] Main::Session &session() const;
 
 	bool finished() const {
 		return _finished;
@@ -153,7 +88,8 @@ public:
 	QString fileName() const {
 		return _filename;
 	}
-	virtual Data::FileOrigin fileOrigin() const;
+	// Used in MainWidget::documentLoadFailed.
+	[[nodiscard]] virtual Data::FileOrigin fileOrigin() const;
 	float64 currentProgress() const;
 	virtual int currentOffset() const;
 	int fullSize() const;
@@ -171,10 +107,6 @@ public:
 		return _autoLoading;
 	}
 
-	virtual void stop() {
-	}
-	virtual ~FileLoader();
-
 	void localLoaded(
 		const StorageImageSaved &result,
 		const QByteArray &imageFormat,
@@ -198,7 +130,7 @@ protected:
 	void loadLocal(const Storage::Cache::Key &key);
 	virtual Storage::Cache::Key cacheKey() const = 0;
 	virtual std::optional<MediaKey> fileLocationKey() const = 0;
-	virtual void cancelRequests() = 0;
+	virtual void cancelHook() = 0;
 	virtual void startLoading() = 0;
 
 	void cancel(bool failed);
diff --git a/Telegram/SourceFiles/storage/file_download_mtproto.cpp b/Telegram/SourceFiles/storage/file_download_mtproto.cpp
index 0cb04513a..bf14e8bfe 100644
--- a/Telegram/SourceFiles/storage/file_download_mtproto.cpp
+++ b/Telegram/SourceFiles/storage/file_download_mtproto.cpp
@@ -35,10 +35,7 @@ mtpFileLoader::mtpFileLoader(
 	fromCloud,
 	autoLoading,
 	cacheTag)
-, _downloader(&session().downloader())
-, _dcId(location.dcId())
-, _location(location)
-, _origin(origin) {
+, DownloadMtprotoTask(&session().downloader(), location, origin) {
 }
 
 mtpFileLoader::mtpFileLoader(
@@ -55,9 +52,10 @@ mtpFileLoader::mtpFileLoader(
 	fromCloud,
 	autoLoading,
 	cacheTag)
-, _downloader(&session().downloader())
-, _dcId(Global::WebFileDcId())
-, _location(location) {
+, DownloadMtprotoTask(
+	&session().downloader(),
+	Global::WebFileDcId(),
+	{ location }) {
 }
 
 mtpFileLoader::mtpFileLoader(
@@ -74,506 +72,85 @@ mtpFileLoader::mtpFileLoader(
 	fromCloud,
 	autoLoading,
 	cacheTag)
-, _downloader(&session().downloader())
-, _dcId(Global::WebFileDcId())
-, _location(location) {
-}
-
-mtpFileLoader::~mtpFileLoader() {
-	cancelRequests();
-	_downloader->remove(this);
+, DownloadMtprotoTask(
+	&session().downloader(),
+	Global::WebFileDcId(),
+	{ location }) {
 }
 
 Data::FileOrigin mtpFileLoader::fileOrigin() const {
-	return _origin;
+	return DownloadMtprotoTask::fileOrigin();
 }
 
 uint64 mtpFileLoader::objId() const {
-	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
-		return storage->objectId();
-	}
-	return 0;
-}
-
-void mtpFileLoader::refreshFileReferenceFrom(
-		const Data::UpdatedFileReferences &updates,
-		int requestId,
-		const QByteArray &current) {
-	if (const auto storage = base::get_if<StorageFileLocation>(&_location)) {
-		storage->refreshFileReference(updates);
-		if (storage->fileReference() == current) {
-			cancel(true);
-			return;
-		}
-	} else {
-		cancel(true);
-		return;
-	}
-	makeRequest(finishSentRequest(requestId));
-}
-
-MTP::DcId mtpFileLoader::dcId() const {
-	return _dcId;
+	return DownloadMtprotoTask::objectId();
 }
 
 bool mtpFileLoader::readyToRequest() const {
 	return !_finished
 		&& !_lastComplete
-		&& (_sentRequests.empty() || _size != 0)
+		&& (_size != 0 || !haveSentRequests())
 		&& (!_size || _nextRequestOffset < _size);
 }
 
-void mtpFileLoader::loadPart(int dcIndex) {
+int mtpFileLoader::takeNextRequestOffset() {
 	Expects(readyToRequest());
 
-	makeRequest({ _nextRequestOffset, dcIndex });
+	const auto result = _nextRequestOffset;
 	_nextRequestOffset += Storage::kDownloadPartSize;
-}
-
-mtpRequestId mtpFileLoader::sendRequest(const RequestData &requestData) {
-	const auto offset = requestData.offset;
-	const auto limit = Storage::kDownloadPartSize;
-	const auto shiftedDcId = MTP::downloadDcId(
-		_cdnDcId ? _cdnDcId : dcId(),
-		requestData.dcIndex);
-	if (_cdnDcId) {
-		return MTP::send(
-			MTPupload_GetCdnFile(
-				MTP_bytes(_cdnToken),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::cdnPartLoaded),
-			rpcFail(&mtpFileLoader::cdnPartFailed),
-			shiftedDcId,
-			50);
-	}
-	return _location.match([&](const WebFileLocation &location) {
-		return MTP::send(
-			MTPupload_GetWebFile(
-				MTP_inputWebFileLocation(
-					MTP_bytes(location.url()),
-					MTP_long(location.accessHash())),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::webPartLoaded),
-			rpcFail(&mtpFileLoader::partFailed),
-			shiftedDcId,
-			50);
-	}, [&](const GeoPointLocation &location) {
-		return MTP::send(
-			MTPupload_GetWebFile(
-				MTP_inputWebFileGeoPointLocation(
-					MTP_inputGeoPoint(
-						MTP_double(location.lat),
-						MTP_double(location.lon)),
-					MTP_long(location.access),
-					MTP_int(location.width),
-					MTP_int(location.height),
-					MTP_int(location.zoom),
-					MTP_int(location.scale)),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::webPartLoaded),
-			rpcFail(&mtpFileLoader::partFailed),
-			shiftedDcId,
-			50);
-	}, [&](const StorageFileLocation &location) {
-		return MTP::send(
-			MTPupload_GetFile(
-				MTP_flags(0),
-				location.tl(session().userId()),
-				MTP_int(offset),
-				MTP_int(limit)),
-			rpcDone(&mtpFileLoader::normalPartLoaded),
-			rpcFail(
-				&mtpFileLoader::normalPartFailed,
-				location.fileReference()),
-			shiftedDcId,
-			50);
-	});
-}
-
-void mtpFileLoader::makeRequest(const RequestData &requestData) {
-	Expects(!_finished);
-
-	placeSentRequest(sendRequest(requestData), requestData);
-}
-
-void mtpFileLoader::requestMoreCdnFileHashes() {
-	Expects(!_finished);
-
-	if (_cdnHashesRequestId || _cdnUncheckedParts.empty()) {
-		return;
-	}
-
-	const auto requestData = _cdnUncheckedParts.cbegin()->first;
-	const auto shiftedDcId = MTP::downloadDcId(
-		dcId(),
-		requestData.dcIndex);
-	const auto requestId = _cdnHashesRequestId = MTP::send(
-		MTPupload_GetCdnFileHashes(
-			MTP_bytes(_cdnToken),
-			MTP_int(requestData.offset)),
-		rpcDone(&mtpFileLoader::getCdnFileHashesDone),
-		rpcFail(&mtpFileLoader::cdnPartFailed),
-		shiftedDcId);
-	placeSentRequest(requestId, requestData);
-}
-
-void mtpFileLoader::normalPartLoaded(
-		const MTPupload_File &result,
-		mtpRequestId requestId) {
-	Expects(!_finished);
-
-	const auto requestData = finishSentRequest(requestId);
-	result.match([&](const MTPDupload_fileCdnRedirect &data) {
-		switchToCDN(requestData, data);
-	}, [&](const MTPDupload_file &data) {
-		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
-	});
-}
-
-void mtpFileLoader::webPartLoaded(
-		const MTPupload_WebFile &result,
-		mtpRequestId requestId) {
-	result.match([&](const MTPDupload_webFile &data) {
-		const auto requestData = finishSentRequest(requestId);
-		if (!_size) {
-			_size = data.vsize().v;
-		} else if (data.vsize().v != _size) {
-			LOG(("MTP Error: "
-				"Bad size provided by bot for webDocument: %1, real: %2"
-				).arg(_size
-				).arg(data.vsize().v));
-			cancel(true);
-			return;
-		}
-		partLoaded(requestData.offset, bytes::make_span(data.vbytes().v));
-	});
-}
-
-void mtpFileLoader::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId) {
-	Expects(!_finished);
-
-	const auto requestData = finishSentRequest(requestId);
-	result.match([&](const MTPDupload_cdnFileReuploadNeeded &data) {
-		const auto shiftedDcId = MTP::downloadDcId(
-			dcId(),
-			requestData.dcIndex);
-		const auto requestId = MTP::send(
-			MTPupload_ReuploadCdnFile(
-				MTP_bytes(_cdnToken),
-				data.vrequest_token()),
-			rpcDone(&mtpFileLoader::reuploadDone),
-			rpcFail(&mtpFileLoader::cdnPartFailed),
-			shiftedDcId);
-		placeSentRequest(requestId, requestData);
-	}, [&](const MTPDupload_cdnFile &data) {
-		auto key = bytes::make_span(_cdnEncryptionKey);
-		auto iv = bytes::make_span(_cdnEncryptionIV);
-		Expects(key.size() == MTP::CTRState::KeySize);
-		Expects(iv.size() == MTP::CTRState::IvecSize);
-
-		auto state = MTP::CTRState();
-		auto ivec = bytes::make_span(state.ivec);
-		std::copy(iv.begin(), iv.end(), ivec.begin());
-
-		auto counterOffset = static_cast<uint32>(requestData.offset) >> 4;
-		state.ivec[15] = static_cast<uchar>(counterOffset & 0xFF);
-		state.ivec[14] = static_cast<uchar>((counterOffset >> 8) & 0xFF);
-		state.ivec[13] = static_cast<uchar>((counterOffset >> 16) & 0xFF);
-		state.ivec[12] = static_cast<uchar>((counterOffset >> 24) & 0xFF);
-
-		auto decryptInPlace = data.vbytes().v;
-		auto buffer = bytes::make_detached_span(decryptInPlace);
-		MTP::aesCtrEncrypt(buffer, key.data(), &state);
-
-		switch (checkCdnFileHash(requestData.offset, buffer)) {
-		case CheckCdnHashResult::NoHash: {
-			_cdnUncheckedParts.emplace(requestData, decryptInPlace);
-			requestMoreCdnFileHashes();
-		} return;
-
-		case CheckCdnHashResult::Invalid: {
-			LOG(("API Error: Wrong cdnFileHash for offset %1."
-				).arg(requestData.offset));
-			cancel(true);
-		} return;
-
-		case CheckCdnHashResult::Good: {
-			partLoaded(requestData.offset, buffer);
-		} return;
-		}
-		Unexpected("Result of checkCdnFileHash()");
-	});
-}
-
-mtpFileLoader::CheckCdnHashResult mtpFileLoader::checkCdnFileHash(
-		int offset,
-		bytes::const_span buffer) {
-	const auto cdnFileHashIt = _cdnFileHashes.find(offset);
-	if (cdnFileHashIt == _cdnFileHashes.cend()) {
-		return CheckCdnHashResult::NoHash;
-	}
-	const auto realHash = openssl::Sha256(buffer);
-	const auto receivedHash = bytes::make_span(cdnFileHashIt->second.hash);
-	if (bytes::compare(realHash, receivedHash)) {
-		return CheckCdnHashResult::Invalid;
-	}
-	return CheckCdnHashResult::Good;
-}
-
-void mtpFileLoader::reuploadDone(
-		const MTPVector<MTPFileHash> &result,
-		mtpRequestId requestId) {
-	const auto requestData = finishSentRequest(requestId);
-	addCdnHashes(result.v);
-	makeRequest(requestData);
-}
-
-void mtpFileLoader::getCdnFileHashesDone(
-		const MTPVector<MTPFileHash> &result,
-		mtpRequestId requestId) {
-	Expects(!_finished);
-	Expects(_cdnHashesRequestId == requestId);
-
-	_cdnHashesRequestId = 0;
-
-	const auto requestData = finishSentRequest(requestId);
-	addCdnHashes(result.v);
-	auto someMoreChecked = false;
-	for (auto i = _cdnUncheckedParts.begin(); i != _cdnUncheckedParts.cend();) {
-		const auto uncheckedData = i->first;
-		const auto uncheckedBytes = bytes::make_span(i->second);
-
-		switch (checkCdnFileHash(uncheckedData.offset, uncheckedBytes)) {
-		case CheckCdnHashResult::NoHash: {
-			++i;
-		} break;
-
-		case CheckCdnHashResult::Invalid: {
-			LOG(("API Error: Wrong cdnFileHash for offset %1."
-				).arg(uncheckedData.offset));
-			cancel(true);
-			return;
-		} break;
-
-		case CheckCdnHashResult::Good: {
-			someMoreChecked = true;
-			const auto goodOffset = uncheckedData.offset;
-			const auto goodBytes = std::move(i->second);
-			const auto weak = QPointer<mtpFileLoader>(this);
-			i = _cdnUncheckedParts.erase(i);
-			if (!feedPart(goodOffset, bytes::make_span(goodBytes))
-				|| !weak) {
-				return;
-			} else if (_finished) {
-				notifyAboutProgress();
-				return;
-			}
-		} break;
-
-		default: Unexpected("Result of checkCdnFileHash()");
-		}
-	}
-	if (someMoreChecked) {
-		const auto weak = QPointer<mtpFileLoader>(this);
-		notifyAboutProgress();
-		if (weak) {
-			requestMoreCdnFileHashes();
-		}
-		return;
-	}
-	LOG(("API Error: "
-		"Could not find cdnFileHash for offset %1 "
-		"after getCdnFileHashes request."
-		).arg(requestData.offset));
-	cancel(true);
-}
-
-void mtpFileLoader::placeSentRequest(
-		mtpRequestId requestId,
-		const RequestData &requestData) {
-	Expects(!_finished);
-
-	_downloader->requestedAmountIncrement(
-		dcId(),
-		requestData.dcIndex,
-		Storage::kDownloadPartSize);
-	_sentRequests.emplace(requestId, requestData);
-}
-
-auto mtpFileLoader::finishSentRequest(mtpRequestId requestId)
--> RequestData {
-	auto it = _sentRequests.find(requestId);
-	Assert(it != _sentRequests.cend());
-
-	const auto result = it->second;
-	_downloader->requestedAmountIncrement(
-		dcId(),
-		result.dcIndex,
-		-Storage::kDownloadPartSize);
-	_sentRequests.erase(it);
-
 	return result;
 }
 
-bool mtpFileLoader::feedPart(int offset, bytes::const_span buffer) {
+bool mtpFileLoader::feedPart(int offset, const QByteArray &bytes) {
+	const auto buffer = bytes::make_span(bytes);
 	if (!writeResultPart(offset, buffer)) {
 		return false;
 	}
 	if (buffer.empty() || (buffer.size() % 1024)) { // bad next offset
 		_lastComplete = true;
 	}
-	const auto finished = _sentRequests.empty()
-		&& _cdnUncheckedParts.empty()
+	const auto weak = QPointer<mtpFileLoader>(this);
+	const auto finished = !haveSentRequests()
 		&& (_lastComplete || (_size && _nextRequestOffset >= _size));
 	if (finished) {
-		_downloader->remove(this);
+		removeFromQueue();
 		if (!finalizeResult()) {
 			return false;
 		}
 	}
-	return true;
-}
-
-void mtpFileLoader::partLoaded(int offset, bytes::const_span buffer) {
-	if (feedPart(offset, buffer)) {
+	if (weak) {
 		notifyAboutProgress();
 	}
-}
-
-bool mtpFileLoader::normalPartFailed(
-		QByteArray fileReference,
-		const RPCError &error,
-		mtpRequestId requestId) {
-	if (MTP::isDefaultHandledError(error)) {
-		return false;
-	}
-	if (error.code() == 400
-		&& error.type().startsWith(qstr("FILE_REFERENCE_"))) {
-		session().api().refreshFileReference(
-			_origin,
-			this,
-			requestId,
-			fileReference);
-		return true;
-	}
-	return partFailed(error, requestId);
-}
-
-
-bool mtpFileLoader::partFailed(
-		const RPCError &error,
-		mtpRequestId requestId) {
-	if (MTP::isDefaultHandledError(error)) {
-		return false;
-	}
-	cancel(true);
 	return true;
 }
 
-bool mtpFileLoader::cdnPartFailed(
-		const RPCError &error,
-		mtpRequestId requestId) {
-	if (MTP::isDefaultHandledError(error)) {
-		return false;
-	}
+void mtpFileLoader::cancelOnFail() {
+	cancel(true);
+}
 
-	if (requestId == _cdnHashesRequestId) {
-		_cdnHashesRequestId = 0;
-	}
-	if (error.type() == qstr("FILE_TOKEN_INVALID")
-		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
-		const auto requestData = finishSentRequest(requestId);
-		changeCDNParams(
-			requestData,
-			0,
-			QByteArray(),
-			QByteArray(),
-			QByteArray(),
-			QVector<MTPFileHash>());
+bool mtpFileLoader::setWebFileSizeHook(int size) {
+	if (!_size || _size == size) {
+		_size = size;
 		return true;
 	}
-	return partFailed(error, requestId);
+	LOG(("MTP Error: "
+		"Bad size provided by bot for webDocument: %1, real: %2"
+		).arg(_size
+		).arg(size));
+	cancel(true);
+	return false;
 }
 
 void mtpFileLoader::startLoading() {
-	_downloader->enqueue(this);
+	addToQueue();
 }
 
-void mtpFileLoader::cancelRequests() {
-	while (!_sentRequests.empty()) {
-		auto requestId = _sentRequests.begin()->first;
-		MTP::cancel(requestId);
-		[[maybe_unused]] const auto data = finishSentRequest(requestId);
-	}
-}
-
-void mtpFileLoader::switchToCDN(
-		const RequestData &requestData,
-		const MTPDupload_fileCdnRedirect &redirect) {
-	changeCDNParams(
-		requestData,
-		redirect.vdc_id().v,
-		redirect.vfile_token().v,
-		redirect.vencryption_key().v,
-		redirect.vencryption_iv().v,
-		redirect.vfile_hashes().v);
-}
-
-void mtpFileLoader::addCdnHashes(const QVector<MTPFileHash> &hashes) {
-	for (const auto &hash : hashes) {
-		hash.match([&](const MTPDfileHash &data) {
-			_cdnFileHashes.emplace(
-				data.voffset().v,
-				CdnFileHash{ data.vlimit().v, data.vhash().v });
-		});
-	}
-}
-
-void mtpFileLoader::changeCDNParams(
-		const RequestData &requestData,
-		MTP::DcId dcId,
-		const QByteArray &token,
-		const QByteArray &encryptionKey,
-		const QByteArray &encryptionIV,
-		const QVector<MTPFileHash> &hashes) {
-	if (dcId != 0
-		&& (encryptionKey.size() != MTP::CTRState::KeySize
-			|| encryptionIV.size() != MTP::CTRState::IvecSize)) {
-		LOG(("Message Error: Wrong key (%1) / iv (%2) size in CDN params").arg(encryptionKey.size()).arg(encryptionIV.size()));
-		cancel(true);
-		return;
-	}
-
-	auto resendAllRequests = (_cdnDcId != dcId
-		|| _cdnToken != token
-		|| _cdnEncryptionKey != encryptionKey
-		|| _cdnEncryptionIV != encryptionIV);
-	_cdnDcId = dcId;
-	_cdnToken = token;
-	_cdnEncryptionKey = encryptionKey;
-	_cdnEncryptionIV = encryptionIV;
-	addCdnHashes(hashes);
-
-	if (resendAllRequests && !_sentRequests.empty()) {
-		auto resendRequests = std::vector<RequestData>();
-		resendRequests.reserve(_sentRequests.size());
-		while (!_sentRequests.empty()) {
-			auto requestId = _sentRequests.begin()->first;
-			MTP::cancel(requestId);
-			resendRequests.push_back(finishSentRequest(requestId));
-		}
-		for (const auto &requestData : resendRequests) {
-			makeRequest(requestData);
-		}
-	}
-	makeRequest(requestData);
+void mtpFileLoader::cancelHook() {
+	cancelAllRequests();
 }
 
 Storage::Cache::Key mtpFileLoader::cacheKey() const {
-	return _location.match([&](const WebFileLocation &location) {
+	return location().data.match([&](const WebFileLocation &location) {
 		return Data::WebDocumentCacheKey(location);
 	}, [&](const GeoPointLocation &location) {
 		return Data::GeoPointCacheKey(location);
diff --git a/Telegram/SourceFiles/storage/file_download_mtproto.h b/Telegram/SourceFiles/storage/file_download_mtproto.h
index 01cadd3b2..0906d47d0 100644
--- a/Telegram/SourceFiles/storage/file_download_mtproto.h
+++ b/Telegram/SourceFiles/storage/file_download_mtproto.h
@@ -8,13 +8,11 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #pragma once
 
 #include "storage/file_download.h"
+#include "storage/download_manager_mtproto.h"
 
-class StorageImageLocation;
-class WebFileLocation;
 class mtpFileLoader final
 	: public FileLoader
-	, public RPCSender
-	, public Storage::Downloader {
+	, private Storage::DownloadMtprotoTask {
 public:
 	mtpFileLoader(
 		const StorageFileLocation &location,
@@ -40,101 +38,21 @@ public:
 		uint8 cacheTag);
 
 	Data::FileOrigin fileOrigin() const override;
-
 	uint64 objId() const override;
 
-	void stop() override {
-		rpcInvalidate();
-	}
-	void refreshFileReferenceFrom(
-		const Data::UpdatedFileReferences &updates,
-		int requestId,
-		const QByteArray &current);
-
-	~mtpFileLoader();
-
 private:
-	struct RequestData {
-		int offset = 0;
-		int dcIndex = 0;
-
-		inline bool operator<(const RequestData &other) const {
-			return offset < other.offset;
-		}
-	};
-	struct CdnFileHash {
-		CdnFileHash(int limit, QByteArray hash) : limit(limit), hash(hash) {
-		}
-		int limit = 0;
-		QByteArray hash;
-	};
 	Storage::Cache::Key cacheKey() const override;
 	std::optional<MediaKey> fileLocationKey() const override;
 	void startLoading() override;
-	void cancelRequests() override;
+	void cancelHook() override;
 
-	void makeRequest(const RequestData &requestData);
-
-	MTP::DcId dcId() const override;
 	bool readyToRequest() const override;
-	void loadPart(int dcIndex) override;
-	void normalPartLoaded(const MTPupload_File &result, mtpRequestId requestId);
-	void webPartLoaded(const MTPupload_WebFile &result, mtpRequestId requestId);
-	void cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId);
-	void reuploadDone(const MTPVector<MTPFileHash> &result, mtpRequestId requestId);
-	void requestMoreCdnFileHashes();
-	void getCdnFileHashesDone(const MTPVector<MTPFileHash> &result, mtpRequestId requestId);
-
-	void partLoaded(int offset, bytes::const_span buffer);
-	bool feedPart(int offset, bytes::const_span buffer);
-
-	bool partFailed(const RPCError &error, mtpRequestId requestId);
-	bool normalPartFailed(QByteArray fileReference, const RPCError &error, mtpRequestId requestId);
-	bool cdnPartFailed(const RPCError &error, mtpRequestId requestId);
-
-	mtpRequestId sendRequest(const RequestData &requestData);
-	void placeSentRequest(
-		mtpRequestId requestId,
-		const RequestData &requestData);
-	[[nodiscard]] RequestData finishSentRequest(mtpRequestId requestId);
-	void switchToCDN(
-		const RequestData &requestData,
-		const MTPDupload_fileCdnRedirect &redirect);
-	void addCdnHashes(const QVector<MTPFileHash> &hashes);
-	void changeCDNParams(
-		const RequestData &requestData,
-		MTP::DcId dcId,
-		const QByteArray &token,
-		const QByteArray &encryptionKey,
-		const QByteArray &encryptionIV,
-		const QVector<MTPFileHash> &hashes);
-
-	enum class CheckCdnHashResult {
-		NoHash,
-		Invalid,
-		Good,
-	};
-	CheckCdnHashResult checkCdnFileHash(int offset, bytes::const_span buffer);
-
-	const not_null<Storage::DownloadManager*> _downloader;
-	const MTP::DcId _dcId = 0;
-	std::map<mtpRequestId, RequestData> _sentRequests;
+	int takeNextRequestOffset() override;
+	bool feedPart(int offset, const QByteArray &bytes) override;
+	void cancelOnFail() override;
+	bool setWebFileSizeHook(int size) override;
 
 	bool _lastComplete = false;
 	int32 _nextRequestOffset = 0;
 
-	base::variant<
-		StorageFileLocation,
-		WebFileLocation,
-		GeoPointLocation> _location;
-	Data::FileOrigin _origin;
-
-	MTP::DcId _cdnDcId = 0;
-	QByteArray _cdnToken;
-	QByteArray _cdnEncryptionKey;
-	QByteArray _cdnEncryptionIV;
-	base::flat_map<int, CdnFileHash> _cdnFileHashes;
-	base::flat_map<RequestData, QByteArray> _cdnUncheckedParts;
-	mtpRequestId _cdnHashesRequestId = 0;
-
 };
diff --git a/Telegram/SourceFiles/storage/file_download_web.cpp b/Telegram/SourceFiles/storage/file_download_web.cpp
index e9714236a..56764a474 100644
--- a/Telegram/SourceFiles/storage/file_download_web.cpp
+++ b/Telegram/SourceFiles/storage/file_download_web.cpp
@@ -455,7 +455,7 @@ webFileLoader::webFileLoader(
 }
 
 webFileLoader::~webFileLoader() {
-	cancelRequests();
+	cancelRequest();
 }
 
 QString webFileLoader::url() const {
@@ -493,7 +493,7 @@ void webFileLoader::loadProgress(qint64 ready, qint64 total) {
 }
 
 void webFileLoader::loadFinished(const QByteArray &data) {
-	cancelRequests();
+	cancelRequest();
 	if (writeResultPart(0, bytes::make_span(data))) {
 		if (finalizeResult()) {
 			notifyAboutProgress();
@@ -513,11 +513,11 @@ std::optional<MediaKey> webFileLoader::fileLocationKey() const {
 	return std::nullopt;
 }
 
-void webFileLoader::stop() {
-	cancelRequests();
+void webFileLoader::cancelHook() {
+	cancelRequest();
 }
 
-void webFileLoader::cancelRequests() {
+void webFileLoader::cancelRequest() {
 	if (!_manager) {
 		return;
 	}
diff --git a/Telegram/SourceFiles/storage/file_download_web.h b/Telegram/SourceFiles/storage/file_download_web.h
index bfc1b8638..9c832ae00 100644
--- a/Telegram/SourceFiles/storage/file_download_web.h
+++ b/Telegram/SourceFiles/storage/file_download_web.h
@@ -24,10 +24,10 @@ public:
 	[[nodiscard]] QString url() const;
 
 	int currentOffset() const override;
-	void stop() override;
-	void cancelRequests() override;
 
 private:
+	void cancelRequest();
+	void cancelHook() override;
 	void startLoading() override;
 	Storage::Cache::Key cacheKey() const override;
 	std::optional<MediaKey> fileLocationKey() const override;
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
index d5afb2a43..db3558efa 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.cpp
@@ -63,7 +63,7 @@ StreamedFileDownloader::StreamedFileDownloader(
 }
 
 StreamedFileDownloader::~StreamedFileDownloader() {
-	stop();
+	cancelHook();
 }
 
 uint64 StreamedFileDownloader::objId() const {
@@ -74,10 +74,6 @@ Data::FileOrigin StreamedFileDownloader::fileOrigin() const {
 	return _origin;
 }
 
-void StreamedFileDownloader::stop() {
-	cancelRequests();
-}
-
 void StreamedFileDownloader::requestParts() {
 	while (!_finished
 		&& _nextPartIndex < _partsCount
@@ -121,7 +117,7 @@ std::optional<MediaKey> StreamedFileDownloader::fileLocationKey() const {
 	return _fileLocationKey;
 }
 
-void StreamedFileDownloader::cancelRequests() {
+void StreamedFileDownloader::cancelHook() {
 	_partsRequested = 0;
 	_nextPartIndex = 0;
 
diff --git a/Telegram/SourceFiles/storage/streamed_file_downloader.h b/Telegram/SourceFiles/storage/streamed_file_downloader.h
index 43aa5e575..1fbef7a33 100644
--- a/Telegram/SourceFiles/storage/streamed_file_downloader.h
+++ b/Telegram/SourceFiles/storage/streamed_file_downloader.h
@@ -9,6 +9,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include "storage/file_download.h"
 #include "storage/cache/storage_cache_types.h"
+#include "data/data_file_origin.h"
 
 namespace Media {
 namespace Streaming {
@@ -41,7 +42,6 @@ public:
 
 	uint64 objId() const override;
 	Data::FileOrigin fileOrigin() const override;
-	void stop() override;
 
 	QByteArray readLoadedPart(int offset);
 
@@ -49,7 +49,7 @@ private:
 	void startLoading() override;
 	Cache::Key cacheKey() const override;
 	std::optional<MediaKey> fileLocationKey() const override;
-	void cancelRequests() override;
+	void cancelHook() override;
 	void requestParts();
 	void requestPart();
 
diff --git a/Telegram/SourceFiles/ui/image/image_source.cpp b/Telegram/SourceFiles/ui/image/image_source.cpp
index d5ae427c7..c55c962a1 100644
--- a/Telegram/SourceFiles/ui/image/image_source.cpp
+++ b/Telegram/SourceFiles/ui/image/image_source.cpp
@@ -306,7 +306,6 @@ void RemoteSource::destroyLoader() {
 	if (cancelled()) {
 		loader->cancel();
 	}
-	loader->stop();
 }
 
 void RemoteSource::loadLocal() {
diff --git a/Telegram/SourceFiles/window/notifications_manager_default.cpp b/Telegram/SourceFiles/window/notifications_manager_default.cpp
index 5d4239515..b70b25fe3 100644
--- a/Telegram/SourceFiles/window/notifications_manager_default.cpp
+++ b/Telegram/SourceFiles/window/notifications_manager_default.cpp
@@ -65,7 +65,7 @@ std::unique_ptr<Manager> Create(System *system) {
 Manager::Manager(System *system)
 : Notifications::Manager(system)
 , _inputCheckTimer([=] { checkLastInput(); }) {
-	subscribe(system->session().downloader().taskFinished(), [this] {
+	subscribe(system->session().downloaderTaskFinished(), [this] {
 		for (const auto &notification : _notifications) {
 			notification->updatePeerPhoto();
 		}
diff --git a/Telegram/gyp/telegram/sources.txt b/Telegram/gyp/telegram/sources.txt
index 14afd962a..2fbc09079 100644
--- a/Telegram/gyp/telegram/sources.txt
+++ b/Telegram/gyp/telegram/sources.txt
@@ -683,6 +683,8 @@
 <(src_loc)/settings/settings_privacy_controllers.h
 <(src_loc)/settings/settings_privacy_security.cpp
 <(src_loc)/settings/settings_privacy_security.h
+<(src_loc)/storage/download_manager_mtproto.cpp
+<(src_loc)/storage/download_manager_mtproto.h
 <(src_loc)/storage/file_download.cpp
 <(src_loc)/storage/file_download.h
 <(src_loc)/storage/file_download_mtproto.cpp

From e426f2895b70d0f2b1d9c18b0d7a329a15cd74f6 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 5 Dec 2019 14:46:28 +0300
Subject: [PATCH 89/91] Add download sessions if it works fast enough.

---
 Telegram/SourceFiles/mtproto/mtp_instance.cpp |  20 ++
 Telegram/SourceFiles/mtproto/mtp_instance.h   |   3 +
 .../SourceFiles/mtproto/session_private.cpp   |  21 +-
 .../storage/download_manager_mtproto.cpp      | 309 +++++++++++++-----
 .../storage/download_manager_mtproto.h        |  46 ++-
 .../SourceFiles/storage/file_download_web.cpp |   4 +-
 6 files changed, 295 insertions(+), 108 deletions(-)

diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.cpp b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
index b48ddf734..0af0dc90d 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.cpp
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.cpp
@@ -85,6 +85,9 @@ public:
 	void badConfigurationError();
 	void syncHttpUnixtime();
 
+	void restartedByTimeout(ShiftedDcId shiftedDcId);
+	[[nodiscard]] rpl::producer<ShiftedDcId> restartsByTimeout() const;
+
 	void restart();
 	void restart(ShiftedDcId shiftedDcId);
 	[[nodiscard]] int32 dcstate(ShiftedDcId shiftedDcId = 0);
@@ -208,6 +211,7 @@ private:
 	Session *_mainSession = nullptr;
 	base::flat_map<ShiftedDcId, std::unique_ptr<Session>> _sessions;
 	std::vector<std::unique_ptr<Session>> _sessionsToDestroy;
+	rpl::event_stream<ShiftedDcId> _restartsByTimeout;
 
 	std::unique_ptr<ConfigLoader> _configLoader;
 	std::unique_ptr<DomainResolver> _domainResolver;
@@ -446,6 +450,14 @@ void Instance::Private::syncHttpUnixtime() {
 	});
 }
 
+void Instance::Private::restartedByTimeout(ShiftedDcId shiftedDcId) {
+	_restartsByTimeout.fire_copy(shiftedDcId);
+}
+
+rpl::producer<ShiftedDcId> Instance::Private::restartsByTimeout() const {
+	return _restartsByTimeout.events();
+}
+
 void Instance::Private::requestConfigIfOld() {
 	const auto timeout = Global::BlockedMode()
 		? kConfigBecomesOldForBlockedIn
@@ -1664,6 +1676,14 @@ void Instance::syncHttpUnixtime() {
 	_private->syncHttpUnixtime();
 }
 
+void Instance::restartedByTimeout(ShiftedDcId shiftedDcId) {
+	_private->restartedByTimeout(shiftedDcId);
+}
+
+rpl::producer<ShiftedDcId> Instance::restartsByTimeout() const {
+	return _private->restartsByTimeout();
+}
+
 void Instance::requestConfigIfOld() {
 	_private->requestConfigIfOld();
 }
diff --git a/Telegram/SourceFiles/mtproto/mtp_instance.h b/Telegram/SourceFiles/mtproto/mtp_instance.h
index 834ef947d..ed3797307 100644
--- a/Telegram/SourceFiles/mtproto/mtp_instance.h
+++ b/Telegram/SourceFiles/mtproto/mtp_instance.h
@@ -120,6 +120,9 @@ public:
 	void setUserPhone(const QString &phone);
 	void badConfigurationError();
 
+	void restartedByTimeout(ShiftedDcId shiftedDcId);
+	[[nodiscard]] rpl::producer<ShiftedDcId> restartsByTimeout() const;
+
 	void syncHttpUnixtime();
 
 	void sendAnything(ShiftedDcId shiftedDcId = 0, crl::time msCanWait = 0);
diff --git a/Telegram/SourceFiles/mtproto/session_private.cpp b/Telegram/SourceFiles/mtproto/session_private.cpp
index 9ee0039a5..96a95999f 100644
--- a/Telegram/SourceFiles/mtproto/session_private.cpp
+++ b/Telegram/SourceFiles/mtproto/session_private.cpp
@@ -1036,7 +1036,9 @@ void SessionPrivate::onSentSome(uint64 size) {
 		}
 		_waitForReceivedTimer.callOnce(remain);
 	}
-	if (!_firstSentAt) _firstSentAt = crl::now();
+	if (!_firstSentAt) {
+		_firstSentAt = crl::now();
+	}
 }
 
 void SessionPrivate::onReceivedSome() {
@@ -1048,7 +1050,9 @@ void SessionPrivate::onReceivedSome() {
 	_waitForReceivedTimer.cancel();
 	if (_firstSentAt > 0) {
 		const auto ms = crl::now() - _firstSentAt;
-		DEBUG_LOG(("MTP Info: response in %1ms, _waitForReceived: %2ms").arg(ms).arg(_waitForReceived));
+		DEBUG_LOG(("MTP Info: response in %1ms, _waitForReceived: %2ms"
+			).arg(ms
+			).arg(_waitForReceived));
 
 		if (ms > 0 && ms * 2 < _waitForReceived) {
 			_waitForReceived = qMax(ms * 2, kMinReceiveTimeout);
@@ -1060,7 +1064,8 @@ void SessionPrivate::onReceivedSome() {
 void SessionPrivate::markConnectionOld() {
 	_oldConnection = true;
 	_waitForReceived = kMinReceiveTimeout;
-	DEBUG_LOG(("This connection marked as old! _waitForReceived now %1ms").arg(_waitForReceived));
+	DEBUG_LOG(("This connection marked as old! _waitForReceived now %1ms"
+		).arg(_waitForReceived));
 }
 
 void SessionPrivate::sendPingByTimer() {
@@ -1094,10 +1099,6 @@ void SessionPrivate::sendPingForce() {
 void SessionPrivate::waitReceivedFailed() {
 	Expects(_options != nullptr);
 
-	if (!_options->useTcp) {
-		return;
-	}
-
 	DEBUG_LOG(("MTP Info: bad connection, _waitForReceived: %1ms").arg(_waitForReceived));
 	if (_waitForReceived < kMaxReceiveTimeout) {
 		_waitForReceived *= 2;
@@ -1109,6 +1110,12 @@ void SessionPrivate::waitReceivedFailed() {
 
 	DEBUG_LOG(("MTP Info: immediate restart!"));
 	InvokeQueued(this, [=] { connectToServer(); });
+
+	const auto instance = _instance;
+	const auto shiftedDcId = _shiftedDcId;
+	InvokeQueued(instance, [=] {
+		instance->restartedByTimeout(shiftedDcId);
+	});
 }
 
 void SessionPrivate::waitConnectedFailed() {
diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
index 92c0d828f..f60787f1c 100644
--- a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
@@ -17,21 +17,23 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 namespace Storage {
 namespace {
 
-// How much time without download causes additional session kill.
 constexpr auto kKillSessionTimeout = 15 * crl::time(1000);
-
-// Max 16 file parts downloaded at the same time, 128 KB each.
-constexpr auto kMaxFileQueries = 16;
-
-constexpr auto kMaxWaitedInConnection = 512 * 1024;
-
-// Max 8 http[s] files downloaded at the same time.
-constexpr auto kMaxWebFileQueries = 8;
-
+constexpr auto kMaxWaitedInSession = 2 * 1024 * 1024;
 constexpr auto kStartSessionsCount = 1;
 constexpr auto kMaxSessionsCount = 8;
+constexpr auto kMaxTrackedSessionRemoves = 64;
+constexpr auto kRetryAddSessionTimeout = 8 * crl::time(1000);
+constexpr auto kRetryAddSessionSuccesses = 3;
+constexpr auto kMaxTrackedSuccesses = kRetryAddSessionSuccesses
+	* kMaxTrackedSessionRemoves;
+constexpr auto kRemoveSessionAfterTimeouts = 2;
 constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
 
+// Each session remove by timeouts we wait for time
+// kRetryAddSessionTimeout * max(removesCount, kMaxTrackedSessionRemoves)
+// and for successes in all remaining sessions
+// kRetryAddSessionSuccesses * max(removesCount, kMaxTrackedSessionRemoves)
+
 } // namespace
 
 void DownloadManagerMtproto::Queue::enqueue(not_null<Task*> task) {
@@ -74,14 +76,30 @@ auto DownloadManagerMtproto::Queue::nextTask() const -> Task* {
 	return (i != all.end()) ? i->get() : nullptr;
 }
 
+DownloadManagerMtproto::DcSessionBalanceData::DcSessionBalanceData()
+: maxWaitedAmount(kDownloadPartSize) {
+}
+
+DownloadManagerMtproto::DcBalanceData::DcBalanceData()
+: sessions(kStartSessionsCount) {
+}
+
 DownloadManagerMtproto::DownloadManagerMtproto(not_null<ApiWrap*> api)
 : _api(api)
 , _resetGenerationTimer([=] { resetGeneration(); })
-, _killDownloadSessionsTimer([=] { killDownloadSessions(); }) {
+, _killSessionsTimer([=] { killSessions(); }) {
+	_api->instance()->restartsByTimeout(
+	) | rpl::filter([](MTP::ShiftedDcId shiftedDcId) {
+		return MTP::isDownloadDcId(shiftedDcId);
+	}) | rpl::start_with_next([=](MTP::ShiftedDcId shiftedDcId) {
+		sessionTimedOut(
+			MTP::BareDcId(shiftedDcId),
+			MTP::GetDcIdShift(shiftedDcId));
+	}, _lifetime);
 }
 
 DownloadManagerMtproto::~DownloadManagerMtproto() {
-	killDownloadSessions();
+	killSessions();
 }
 
 void DownloadManagerMtproto::enqueue(not_null<Task*> task) {
@@ -98,7 +116,6 @@ void DownloadManagerMtproto::remove(not_null<Task*> task) {
 	const auto dcId = task->dcId();
 	auto &queue = _queues[dcId];
 	queue.remove(task);
-	checkSendNext(dcId, queue);
 }
 
 void DownloadManagerMtproto::resetGeneration() {
@@ -118,89 +135,158 @@ void DownloadManagerMtproto::checkSendNext() {
 }
 
 void DownloadManagerMtproto::checkSendNext(MTP::DcId dcId, Queue &queue) {
+	while (trySendNextPart(dcId, queue)) {
+	}
+}
+
+bool DownloadManagerMtproto::trySendNextPart(MTP::DcId dcId, Queue &queue) {
 	const auto bestIndex = [&] {
-		const auto i = _requestedBytesAmount.find(dcId);
-		if (i == end(_requestedBytesAmount)) {
-			_requestedBytesAmount[dcId].resize(kStartSessionsCount);
-			return 0;
-		}
-		const auto j = ranges::min_element(i->second);
-		const auto already = *j;
-		return (already + kDownloadPartSize <= kMaxWaitedInConnection)
-			? (j - begin(i->second))
+		const auto &sessions = _balanceData[dcId].sessions;
+		const auto proj = [](const DcSessionBalanceData &data) {
+			return (data.requested < data.maxWaitedAmount)
+				? data.requested
+				: kMaxWaitedInSession;
+		};
+		const auto j = ranges::min_element(sessions, ranges::less(), proj);
+		return (j->requested + kDownloadPartSize <= j->maxWaitedAmount)
+			? (j - begin(sessions))
 			: -1;
 	}();
-	if (bestIndex >= 0) {
-		if (const auto task = queue.nextTask()) {
-			task->loadPart(bestIndex);
-		}
+	if (bestIndex < 0) {
+		return false;
 	}
+	if (const auto task = queue.nextTask()) {
+		task->loadPart(bestIndex);
+		return true;
+	}
+	return false;
 }
 
-void DownloadManagerMtproto::requestedAmountIncrement(
+void DownloadManagerMtproto::changeRequestedAmount(
 		MTP::DcId dcId,
 		int index,
-		int amount) {
-	Expects(dcId != 0);
+		int delta) {
+	const auto i = _balanceData.find(dcId);
+	Assert(i != _balanceData.end());
+	Assert(index < i->second.sessions.size());
+	i->second.sessions[index].requested += delta;
+	const auto findNonEmptySession = [](const DcBalanceData &data) {
+		using namespace rpl::mappers;
+		return ranges::find_if(
+			data.sessions,
+			_1 > 0,
+			&DcSessionBalanceData::requested);
+	};
+	if (delta > 0) {
+		killSessionsCancel(dcId);
+	} else if (findNonEmptySession(i->second) == end(i->second.sessions)) {
+		killSessionsSchedule(dcId);
+	}
+}
 
+void DownloadManagerMtproto::requestSucceeded(MTP::DcId dcId, int index) {
 	using namespace rpl::mappers;
 
-	auto it = _requestedBytesAmount.find(dcId);
-	if (it == _requestedBytesAmount.end()) {
-		it = _requestedBytesAmount.emplace(
-			dcId,
-			std::vector<int>(dcId ? kStartSessionsCount : 1, 0)
-		).first;
+	DEBUG_LOG(("Download (%1,%2) request done.").arg(dcId).arg(index));
+	const auto i = _balanceData.find(dcId);
+	Assert(i != end(_balanceData));
+	auto &dc = i->second;
+	Assert(index < dc.sessions.size());
+	auto &data = dc.sessions[index];
+	data.successes = std::min(data.successes + 1, kMaxTrackedSuccesses);
+	data.maxWaitedAmount = std::min(
+		data.maxWaitedAmount + kDownloadPartSize,
+		kMaxWaitedInSession);
+	const auto notEnough = ranges::find_if(
+		dc.sessions,
+		_1 < (dc.sessionRemoveTimes + 1) * kRetryAddSessionSuccesses,
+		&DcSessionBalanceData::successes);
+	if (notEnough != end(dc.sessions)) {
+		return;
 	}
-	it->second[index] += amount;
-	if (amount > 0) {
-		killDownloadSessionsStop(dcId);
+	for (auto &session : dc.sessions) {
+		session.successes = 0;
+	}
+	if (dc.timeouts > 0) {
+		--dc.timeouts;
+		return;
+	} else if (dc.sessions.size() == kMaxSessionsCount) {
+		return;
+	}
+	const auto now = crl::now();
+	const auto delay = (dc.sessionRemoveTimes + 1) * kRetryAddSessionTimeout;
+	if (dc.lastSessionRemove && now < dc.lastSessionRemove + delay) {
+		return;
+	}
+	DEBUG_LOG(("Download (%1,%2) added session."
+		).arg(dcId
+		).arg(dc.sessions.size()));
+	dc.sessions.emplace_back();
+	checkSendNext(dcId, _queues[dcId]);
+}
+
+void DownloadManagerMtproto::sessionTimedOut(MTP::DcId dcId, int index) {
+	const auto i = _balanceData.find(dcId);
+	if (i == end(_balanceData)) {
+		return;
+	}
+	auto &dc = i->second;
+	if (index >= dc.sessions.size()) {
+		return;
+	}
+	DEBUG_LOG(("Download (%1,%2) session timed-out.").arg(dcId).arg(index));
+	for (auto &session : dc.sessions) {
+		session.successes = 0;
+	}
+	if (dc.sessions.size() == kStartSessionsCount
+		|| ++dc.timeouts < kRemoveSessionAfterTimeouts) {
+		return;
+	}
+	dc.timeouts = 0;
+	removeSession(dcId);
+}
+
+void DownloadManagerMtproto::removeSession(MTP::DcId dcId) {
+	auto &dc = _balanceData[dcId];
+	Assert(dc.sessions.size() > kStartSessionsCount);
+	const auto index = int(dc.sessions.size() - 1);
+	DEBUG_LOG(("Download (%1,%2) removing session.").arg(dcId).arg(index));
+	auto &queue = _queues[dcId];
+	if (dc.sessionRemoveIndex == index) {
+		dc.sessionRemoveTimes = std::min(
+			dc.sessionRemoveTimes + 1,
+			kMaxTrackedSessionRemoves);
 	} else {
-		crl::on_main(this, [=] { checkSendNext(); });
-		if (ranges::find_if(it->second, _1 > 0) == end(it->second)) {
-			killDownloadSessionsStart(dcId);
-		}
+		dc.sessionRemoveIndex = index;
+		dc.sessionRemoveTimes = 1;
+	}
+	dc.lastSessionRemove = crl::now();
+//	dc.sessions.pop_back();
+}
+
+void DownloadManagerMtproto::killSessionsSchedule(MTP::DcId dcId) {
+	if (!_killSessionsWhen.contains(dcId)) {
+		_killSessionsWhen.emplace(dcId, crl::now() + kKillSessionTimeout);
+	}
+	if (!_killSessionsTimer.isActive()) {
+		_killSessionsTimer.callOnce(kKillSessionTimeout + 5);
 	}
 }
 
-int DownloadManagerMtproto::chooseDcIndexForRequest(MTP::DcId dcId) {
-	const auto i = _requestedBytesAmount.find(dcId);
-	return (i != end(_requestedBytesAmount))
-		? (ranges::min_element(i->second) - begin(i->second))
-		: 0;
-}
-
-void DownloadManagerMtproto::killDownloadSessionsStart(MTP::DcId dcId) {
-	if (!_killDownloadSessionTimes.contains(dcId)) {
-		_killDownloadSessionTimes.emplace(
-			dcId,
-			crl::now() + kKillSessionTimeout);
-	}
-	if (!_killDownloadSessionsTimer.isActive()) {
-		_killDownloadSessionsTimer.callOnce(kKillSessionTimeout + 5);
+void DownloadManagerMtproto::killSessionsCancel(MTP::DcId dcId) {
+	_killSessionsWhen.erase(dcId);
+	if (_killSessionsWhen.empty()) {
+		_killSessionsTimer.cancel();
 	}
 }
 
-void DownloadManagerMtproto::killDownloadSessionsStop(MTP::DcId dcId) {
-	_killDownloadSessionTimes.erase(dcId);
-	if (_killDownloadSessionTimes.empty()
-		&& _killDownloadSessionsTimer.isActive()) {
-		_killDownloadSessionsTimer.cancel();
-	}
-}
-
-void DownloadManagerMtproto::killDownloadSessions() {
+void DownloadManagerMtproto::killSessions() {
 	const auto now = crl::now();
 	auto left = kKillSessionTimeout;
-	for (auto i = _killDownloadSessionTimes.begin(); i != _killDownloadSessionTimes.end(); ) {
+	for (auto i = begin(_killSessionsWhen); i != end(_killSessionsWhen); ) {
 		if (i->second <= now) {
-			const auto j = _requestedBytesAmount.find(i->first);
-			if (j != end(_requestedBytesAmount)) {
-				for (auto index = 0; index != int(j->second.size()); ++index) {
-					MTP::stopSession(MTP::downloadDcId(i->first, index));
-				}
-			}
-			i = _killDownloadSessionTimes.erase(i);
+			killSessions(i->first);
+			i = _killSessionsWhen.erase(i);
 		} else {
 			if (i->second - now < left) {
 				left = i->second - now;
@@ -208,8 +294,23 @@ void DownloadManagerMtproto::killDownloadSessions() {
 			++i;
 		}
 	}
-	if (!_killDownloadSessionTimes.empty()) {
-		_killDownloadSessionsTimer.callOnce(left);
+	if (!_killSessionsWhen.empty()) {
+		_killSessionsTimer.callOnce(left);
+	}
+}
+
+void DownloadManagerMtproto::killSessions(MTP::DcId dcId) {
+	const auto i = _balanceData.find(dcId);
+	if (i != end(_balanceData)) {
+		auto &dc = i->second;
+		auto sessions = base::take(dc.sessions);
+		dc = DcBalanceData();
+		for (auto j = 0; j != int(sessions.size()); ++j) {
+			Assert(sessions[j].requested == 0);
+			sessions[j] = DcSessionBalanceData();
+			MTP::stopSession(MTP::downloadDcId(dcId, j));
+		}
+		dc.sessions = base::take(sessions);
 	}
 }
 
@@ -270,7 +371,11 @@ void DownloadMtprotoTask::refreshFileReferenceFrom(
 		cancelOnFail();
 		return;
 	}
-	makeRequest(finishSentRequest(requestId));
+	if (_sentRequests.contains(requestId)) {
+		makeRequest(finishSentRequest(
+			requestId,
+			FinishRequestReason::Redirect));
+	}
 }
 
 void DownloadMtprotoTask::loadPart(int dcIndex) {
@@ -370,7 +475,9 @@ void DownloadMtprotoTask::requestMoreCdnFileHashes() {
 void DownloadMtprotoTask::normalPartLoaded(
 		const MTPupload_File &result,
 		mtpRequestId requestId) {
-	const auto requestData = finishSentRequest(requestId);
+	const auto requestData = finishSentRequest(
+		requestId,
+		FinishRequestReason::Success);
 	result.match([&](const MTPDupload_fileCdnRedirect &data) {
 		switchToCDN(requestData, data);
 	}, [&](const MTPDupload_file &data) {
@@ -382,7 +489,9 @@ void DownloadMtprotoTask::webPartLoaded(
 		const MTPupload_WebFile &result,
 		mtpRequestId requestId) {
 	result.match([&](const MTPDupload_webFile &data) {
-		const auto requestData = finishSentRequest(requestId);
+		const auto requestData = finishSentRequest(
+			requestId,
+			FinishRequestReason::Success);
 		if (setWebFileSizeHook(data.vsize().v)) {
 			partLoaded(requestData.offset, data.vbytes().v);
 		}
@@ -390,8 +499,10 @@ void DownloadMtprotoTask::webPartLoaded(
 }
 
 void DownloadMtprotoTask::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequestId requestId) {
-	const auto requestData = finishSentRequest(requestId);
 	result.match([&](const MTPDupload_cdnFileReuploadNeeded &data) {
+		const auto requestData = finishSentRequest(
+			requestId,
+			FinishRequestReason::Redirect);
 		const auto shiftedDcId = MTP::downloadDcId(
 			dcId(),
 			requestData.dcIndex);
@@ -405,6 +516,9 @@ void DownloadMtprotoTask::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequ
 		}).toDC(shiftedDcId).send();
 		placeSentRequest(requestId, requestData);
 	}, [&](const MTPDupload_cdnFile &data) {
+		const auto requestData = finishSentRequest(
+			requestId,
+			FinishRequestReason::Success);
 		auto key = bytes::make_span(_cdnEncryptionKey);
 		auto iv = bytes::make_span(_cdnEncryptionIV);
 		Expects(key.size() == MTP::CTRState::KeySize);
@@ -462,7 +576,9 @@ DownloadMtprotoTask::CheckCdnHashResult DownloadMtprotoTask::checkCdnFileHash(
 void DownloadMtprotoTask::reuploadDone(
 		const MTPVector<MTPFileHash> &result,
 		mtpRequestId requestId) {
-	const auto requestData = finishSentRequest(requestId);
+	const auto requestData = finishSentRequest(
+		requestId,
+		FinishRequestReason::Redirect);
 	addCdnHashes(result.v);
 	makeRequest(requestData);
 }
@@ -474,7 +590,9 @@ void DownloadMtprotoTask::getCdnFileHashesDone(
 
 	_cdnHashesRequestId = 0;
 
-	const auto requestData = finishSentRequest(requestId);
+	const auto requestData = finishSentRequest(
+		requestId,
+		FinishRequestReason::Redirect);
 	addCdnHashes(result.v);
 	auto someMoreChecked = false;
 	for (auto i = _cdnUncheckedParts.begin(); i != _cdnUncheckedParts.cend();) {
@@ -521,7 +639,7 @@ void DownloadMtprotoTask::getCdnFileHashesDone(
 void DownloadMtprotoTask::placeSentRequest(
 		mtpRequestId requestId,
 		const RequestData &requestData) {
-	_owner->requestedAmountIncrement(
+	_owner->changeRequestedAmount(
 		dcId(),
 		requestData.dcIndex,
 		Storage::kDownloadPartSize);
@@ -533,19 +651,26 @@ void DownloadMtprotoTask::placeSentRequest(
 	Ensures(ok1 && ok2);
 }
 
-auto DownloadMtprotoTask::finishSentRequest(mtpRequestId requestId)
+auto DownloadMtprotoTask::finishSentRequest(
+	mtpRequestId requestId,
+	FinishRequestReason reason)
 -> RequestData {
 	auto it = _sentRequests.find(requestId);
 	Assert(it != _sentRequests.cend());
 
 	const auto result = it->second;
-	_owner->requestedAmountIncrement(
+	_owner->changeRequestedAmount(
 		dcId(),
 		result.dcIndex,
 		-Storage::kDownloadPartSize);
 	_sentRequests.erase(it);
-	_requestByOffset.erase(result.offset);
+	const auto ok = _requestByOffset.remove(result.offset);
 
+	if (reason == FinishRequestReason::Success) {
+		_owner->requestSucceeded(dcId(), result.dcIndex);
+	}
+
+	Ensures(ok);
 	return result;
 }
 
@@ -575,7 +700,9 @@ void DownloadMtprotoTask::cancelRequestForOffset(int offset) {
 
 void DownloadMtprotoTask::cancelRequest(mtpRequestId requestId) {
 	api().request(requestId).cancel();
-	[[maybe_unused]] const auto data = finishSentRequest(requestId);
+	[[maybe_unused]] const auto data = finishSentRequest(
+		requestId,
+		FinishRequestReason::Cancel);
 }
 
 void DownloadMtprotoTask::addToQueue() {
@@ -633,7 +760,9 @@ bool DownloadMtprotoTask::cdnPartFailed(
 	}
 	if (error.type() == qstr("FILE_TOKEN_INVALID")
 		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
-		const auto requestData = finishSentRequest(requestId);
+		const auto requestData = finishSentRequest(
+			requestId,
+			FinishRequestReason::Redirect);
 		changeCDNParams(
 			requestData,
 			0,
@@ -702,7 +831,9 @@ void DownloadMtprotoTask::changeCDNParams(
 		while (!_sentRequests.empty()) {
 			const auto requestId = _sentRequests.begin()->first;
 			api().request(requestId).cancel();
-			resendRequests.push_back(finishSentRequest(requestId));
+			resendRequests.push_back(finishSentRequest(
+				requestId,
+				FinishRequestReason::Redirect));
 		}
 		for (const auto &requestData : resendRequests) {
 			makeRequest(requestData);
diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.h b/Telegram/SourceFiles/storage/download_manager_mtproto.h
index 7b78ad35e..fb4dade18 100644
--- a/Telegram/SourceFiles/storage/download_manager_mtproto.h
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.h
@@ -42,8 +42,8 @@ public:
 		return _taskFinishedObservable;
 	}
 
-	void requestedAmountIncrement(MTP::DcId dcId, int index, int amount);
-	[[nodiscard]] int chooseDcIndexForRequest(MTP::DcId dcId);
+	void changeRequestedAmount(MTP::DcId dcId, int index, int delta);
+	void requestSucceeded(MTP::DcId dcId, int index);
 
 private:
 	class Queue final {
@@ -59,27 +59,48 @@ private:
 		std::vector<not_null<Task*>> _previousGeneration;
 
 	};
+	struct DcSessionBalanceData {
+		DcSessionBalanceData();
+
+		int requested = 0;
+		int successes = 0; // Since last timeout in this dc in any session.
+		int maxWaitedAmount = 0;
+	};
+	struct DcBalanceData {
+		DcBalanceData();
+
+		std::vector<DcSessionBalanceData> sessions;
+		crl::time lastSessionRemove = 0;
+		int sessionRemoveIndex = 0;
+		int sessionRemoveTimes = 0;
+		int timeouts = 0; // Since all sessions had successes >= required.
+	};
 
 	void checkSendNext();
 	void checkSendNext(MTP::DcId dcId, Queue &queue);
+	bool trySendNextPart(MTP::DcId dcId, Queue &queue);
 
-	void killDownloadSessionsStart(MTP::DcId dcId);
-	void killDownloadSessionsStop(MTP::DcId dcId);
-	void killDownloadSessions();
+	void killSessionsSchedule(MTP::DcId dcId);
+	void killSessionsCancel(MTP::DcId dcId);
+	void killSessions();
+	void killSessions(MTP::DcId dcId);
 
 	void resetGeneration();
+	void sessionTimedOut(MTP::DcId dcId, int index);
+	void removeSession(MTP::DcId dcId);
 
 	const not_null<ApiWrap*> _api;
 
 	base::Observable<void> _taskFinishedObservable;
 
-	base::flat_map<MTP::DcId, std::vector<int>> _requestedBytesAmount;
+	base::flat_map<MTP::DcId, DcBalanceData> _balanceData;
 	base::Timer _resetGenerationTimer;
 
-	base::flat_map<MTP::DcId, crl::time> _killDownloadSessionTimes;
-	base::Timer _killDownloadSessionsTimer;
+	base::flat_map<MTP::DcId, crl::time> _killSessionsWhen;
+	base::Timer _killSessionsTimer;
 
 	base::flat_map<MTP::DcId, Queue> _queues;
+	rpl::lifetime _lifetime;
 
 };
 
@@ -148,6 +169,11 @@ private:
 		Invalid,
 		Good,
 	};
+	enum class FinishRequestReason {
+		Success,
+		Redirect,
+		Cancel,
+	};
 
 	// Called only if readyToRequest() == true.
 	[[nodiscard]] virtual int takeNextRequestOffset() = 0;
@@ -187,7 +213,9 @@ private:
 	void placeSentRequest(
 		mtpRequestId requestId,
 		const RequestData &requestData);
-	[[nodiscard]] RequestData finishSentRequest(mtpRequestId requestId);
+	[[nodiscard]] RequestData finishSentRequest(
+		mtpRequestId requestId,
+		FinishRequestReason reason);
 	void switchToCDN(
 		const RequestData &requestData,
 		const MTPDupload_fileCdnRedirect &redirect);
diff --git a/Telegram/SourceFiles/storage/file_download_web.cpp b/Telegram/SourceFiles/storage/file_download_web.cpp
index 56764a474..5d1878382 100644
--- a/Telegram/SourceFiles/storage/file_download_web.cpp
+++ b/Telegram/SourceFiles/storage/file_download_web.cpp
@@ -222,7 +222,6 @@ void WebLoadManager::remove(int id) {
 		ranges::remove(_previousGeneration, id, &Enqueued::id),
 		end(_previousGeneration));
 	removeSent(id);
-	checkSendNext();
 }
 
 void WebLoadManager::resetGeneration() {
@@ -258,6 +257,7 @@ void WebLoadManager::removeSent(int id) {
 	if (const auto i = _sent.find(id); i != end(_sent)) {
 		deleteDeferred(i->second.reply);
 		_sent.erase(i);
+		checkSendNext();
 	}
 }
 
@@ -265,11 +265,9 @@ not_null<QNetworkReply*> WebLoadManager::send(int id, const QString &url) {
 	const auto result = _network.get(QNetworkRequest(url));
 	const auto handleProgress = [=](qint64 ready, qint64 total) {
 		progress(id, result, ready, total);
-		checkSendNext();
 	};
 	const auto handleError = [=](QNetworkReply::NetworkError error) {
 		failed(id, result, error);
-		checkSendNext();
 	};
 	connect(result, &QNetworkReply::downloadProgress, handleProgress);
 	connect(result, QNetworkReply_error, handleError);

From 7fb24d77c03db0c6e3ed0578ea96916e045f838d Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 5 Dec 2019 16:38:28 +0300
Subject: [PATCH 90/91] Check request duration when adding sessions.

---
 .../storage/download_manager_mtproto.cpp      | 61 ++++++++++++++-----
 .../storage/download_manager_mtproto.h        |  3 +-
 2 files changed, 47 insertions(+), 17 deletions(-)

diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
index f60787f1c..cf66cfb4a 100644
--- a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
@@ -18,7 +18,8 @@ namespace Storage {
 namespace {
 
 constexpr auto kKillSessionTimeout = 15 * crl::time(1000);
-constexpr auto kMaxWaitedInSession = 2 * 1024 * 1024;
+constexpr auto kStartWaitedInSession = 4 * kDownloadPartSize;
+constexpr auto kMaxWaitedInSession = 16 * kDownloadPartSize;
 constexpr auto kStartSessionsCount = 1;
 constexpr auto kMaxSessionsCount = 8;
 constexpr auto kMaxTrackedSessionRemoves = 64;
@@ -28,10 +29,13 @@ constexpr auto kMaxTrackedSuccesses = kRetryAddSessionSuccesses
 	* kMaxTrackedSessionRemoves;
 constexpr auto kRemoveSessionAfterTimeouts = 2;
 constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
+constexpr auto kGrowMaxWaitedDurationThreshold = crl::time(500);
+constexpr auto kGrowSessionsDurationThreshold = crl::time(500);
+constexpr auto kBadRequestDurationThreshold = crl::time(2000);
 
-// Each session remove by timeouts we wait for time
+// Each (session remove by timeouts) we wait for time:
 // kRetryAddSessionTimeout * max(removesCount, kMaxTrackedSessionRemoves)
-// and for successes in all remaining sessions
+// and for successes in all remaining sessions:
 // kRetryAddSessionSuccesses * max(removesCount, kMaxTrackedSessionRemoves)
 
 } // namespace
@@ -77,7 +81,7 @@ auto DownloadManagerMtproto::Queue::nextTask() const -> Task* {
 }
 
 DownloadManagerMtproto::DcSessionBalanceData::DcSessionBalanceData()
-: maxWaitedAmount(kDownloadPartSize) {
+: maxWaitedAmount(kStartWaitedInSession) {
 }
 
 DownloadManagerMtproto::DcBalanceData::DcBalanceData()
@@ -184,19 +188,44 @@ void DownloadManagerMtproto::changeRequestedAmount(
 	}
 }
 
-void DownloadManagerMtproto::requestSucceeded(MTP::DcId dcId, int index) {
+void DownloadManagerMtproto::requestSucceeded(
+		MTP::DcId dcId,
+		int index,
+		crl::time duration) {
 	using namespace rpl::mappers;
 
-	DEBUG_LOG(("Download (%1,%2) request done.").arg(dcId).arg(index));
+	DEBUG_LOG(("Download (%1,%2) request done, duration %3."
+		).arg(dcId
+		).arg(index
+		).arg(duration));
 	const auto i = _balanceData.find(dcId);
 	Assert(i != end(_balanceData));
 	auto &dc = i->second;
 	Assert(index < dc.sessions.size());
 	auto &data = dc.sessions[index];
+	const auto guard = gsl::finally([&] {
+		checkSendNext(dcId, _queues[dcId]);
+	});
+	const auto parts = data.maxWaitedAmount / kDownloadPartSize;
+	if (duration < kGrowMaxWaitedDurationThreshold * parts) {
+		if (data.maxWaitedAmount < kMaxWaitedInSession) {
+			data.maxWaitedAmount = std::min(
+				data.maxWaitedAmount + kDownloadPartSize,
+				kMaxWaitedInSession);
+			DEBUG_LOG(("Download (%1,%2) increased max waited amount %3."
+				).arg(dcId
+				).arg(index
+				).arg(data.maxWaitedAmount));
+		}
+	}
+	if (duration >= kBadRequestDurationThreshold * parts) {
+		DEBUG_LOG(("Duration too large, signaling time out."));
+		sessionTimedOut(dcId, index);
+		return;
+	} else if (duration >= kGrowSessionsDurationThreshold * parts) {
+		return;
+	}
 	data.successes = std::min(data.successes + 1, kMaxTrackedSuccesses);
-	data.maxWaitedAmount = std::min(
-		data.maxWaitedAmount + kDownloadPartSize,
-		kMaxWaitedInSession);
 	const auto notEnough = ranges::find_if(
 		dc.sessions,
 		_1 < (dc.sessionRemoveTimes + 1) * kRetryAddSessionSuccesses,
@@ -222,7 +251,6 @@ void DownloadManagerMtproto::requestSucceeded(MTP::DcId dcId, int index) {
 		).arg(dcId
 		).arg(dc.sessions.size()));
 	dc.sessions.emplace_back();
-	checkSendNext(dcId, _queues[dcId]);
 }
 
 void DownloadManagerMtproto::sessionTimedOut(MTP::DcId dcId, int index) {
@@ -588,8 +616,6 @@ void DownloadMtprotoTask::getCdnFileHashesDone(
 		mtpRequestId requestId) {
 	Expects(_cdnHashesRequestId == requestId);
 
-	_cdnHashesRequestId = 0;
-
 	const auto requestData = finishSentRequest(
 		requestId,
 		FinishRequestReason::Redirect);
@@ -648,6 +674,8 @@ void DownloadMtprotoTask::placeSentRequest(
 		requestData.offset,
 		requestId);
 
+	i->second.sent = crl::now();
+
 	Ensures(ok1 && ok2);
 }
 
@@ -658,6 +686,9 @@ auto DownloadMtprotoTask::finishSentRequest(
 	auto it = _sentRequests.find(requestId);
 	Assert(it != _sentRequests.cend());
 
+	if (_cdnHashesRequestId == requestId) {
+		_cdnHashesRequestId = 0;
+	}
 	const auto result = it->second;
 	_owner->changeRequestedAmount(
 		dcId(),
@@ -667,7 +698,8 @@ auto DownloadMtprotoTask::finishSentRequest(
 	const auto ok = _requestByOffset.remove(result.offset);
 
 	if (reason == FinishRequestReason::Success) {
-		_owner->requestSucceeded(dcId(), result.dcIndex);
+		const auto duration = crl::now() - result.sent;
+		_owner->requestSucceeded(dcId(), result.dcIndex, duration);
 	}
 
 	Ensures(ok);
@@ -755,9 +787,6 @@ bool DownloadMtprotoTask::cdnPartFailed(
 		return false;
 	}
 
-	if (requestId == _cdnHashesRequestId) {
-		_cdnHashesRequestId = 0;
-	}
 	if (error.type() == qstr("FILE_TOKEN_INVALID")
 		|| error.type() == qstr("REQUEST_TOKEN_INVALID")) {
 		const auto requestData = finishSentRequest(
diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.h b/Telegram/SourceFiles/storage/download_manager_mtproto.h
index fb4dade18..01629a1f1 100644
--- a/Telegram/SourceFiles/storage/download_manager_mtproto.h
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.h
@@ -43,7 +43,7 @@ public:
 	}
 
 	void changeRequestedAmount(MTP::DcId dcId, int index, int delta);
-	void requestSucceeded(MTP::DcId dcId, int index);
+	void requestSucceeded(MTP::DcId dcId, int index, crl::time duration);
 
 private:
 	class Queue final {
@@ -153,6 +153,7 @@ private:
 	struct RequestData {
 		int offset = 0;
 		int dcIndex = 0;
+		crl::time sent = 0;
 
 		inline bool operator<(const RequestData &other) const {
 			return offset < other.offset;

From ae8fb14f9e4e1eb360822700aa897d59689be79b Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Fri, 6 Dec 2019 10:05:38 +0300
Subject: [PATCH 91/91] Use 8 seconds timeout for request duration.

---
 .../storage/download_manager_mtproto.cpp      | 157 +++++++++++++-----
 .../storage/download_manager_mtproto.h        |  16 +-
 2 files changed, 125 insertions(+), 48 deletions(-)

diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
index cf66cfb4a..44e716a94 100644
--- a/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.cpp
@@ -27,11 +27,9 @@ constexpr auto kRetryAddSessionTimeout = 8 * crl::time(1000);
 constexpr auto kRetryAddSessionSuccesses = 3;
 constexpr auto kMaxTrackedSuccesses = kRetryAddSessionSuccesses
 	* kMaxTrackedSessionRemoves;
-constexpr auto kRemoveSessionAfterTimeouts = 2;
+constexpr auto kRemoveSessionAfterTimeouts = 4;
 constexpr auto kResetDownloadPrioritiesTimeout = crl::time(200);
-constexpr auto kGrowMaxWaitedDurationThreshold = crl::time(500);
-constexpr auto kGrowSessionsDurationThreshold = crl::time(500);
-constexpr auto kBadRequestDurationThreshold = crl::time(2000);
+constexpr auto kBadRequestDurationThreshold = 8 * crl::time(1000);
 
 // Each (session remove by timeouts) we wait for time:
 // kRetryAddSessionTimeout * max(removesCount, kMaxTrackedSessionRemoves)
@@ -80,6 +78,13 @@ auto DownloadManagerMtproto::Queue::nextTask() const -> Task* {
 	return (i != all.end()) ? i->get() : nullptr;
 }
 
+void DownloadManagerMtproto::Queue::removeSession(int index) {
+	auto &&all = ranges::view::concat(_tasks, _previousGeneration);
+	for (const auto task : all) {
+		task->removeSession(index);
+	}
+}
+
 DownloadManagerMtproto::DcSessionBalanceData::DcSessionBalanceData()
 : maxWaitedAmount(kStartWaitedInSession) {
 }
@@ -166,14 +171,14 @@ bool DownloadManagerMtproto::trySendNextPart(MTP::DcId dcId, Queue &queue) {
 	return false;
 }
 
-void DownloadManagerMtproto::changeRequestedAmount(
+int DownloadManagerMtproto::changeRequestedAmount(
 		MTP::DcId dcId,
 		int index,
 		int delta) {
 	const auto i = _balanceData.find(dcId);
 	Assert(i != _balanceData.end());
 	Assert(index < i->second.sessions.size());
-	i->second.sessions[index].requested += delta;
+	const auto result = (i->second.sessions[index].requested += delta);
 	const auto findNonEmptySession = [](const DcBalanceData &data) {
 		using namespace rpl::mappers;
 		return ranges::find_if(
@@ -186,44 +191,53 @@ void DownloadManagerMtproto::changeRequestedAmount(
 	} else if (findNonEmptySession(i->second) == end(i->second.sessions)) {
 		killSessionsSchedule(dcId);
 	}
+	return result;
 }
 
 void DownloadManagerMtproto::requestSucceeded(
 		MTP::DcId dcId,
 		int index,
-		crl::time duration) {
+		int amountAtRequestStart,
+		crl::time timeAtRequestStart) {
 	using namespace rpl::mappers;
 
-	DEBUG_LOG(("Download (%1,%2) request done, duration %3."
-		).arg(dcId
-		).arg(index
-		).arg(duration));
+	const auto guard = gsl::finally([&] {
+		checkSendNext(dcId, _queues[dcId]);
+	});
+
 	const auto i = _balanceData.find(dcId);
 	Assert(i != end(_balanceData));
 	auto &dc = i->second;
 	Assert(index < dc.sessions.size());
 	auto &data = dc.sessions[index];
-	const auto guard = gsl::finally([&] {
-		checkSendNext(dcId, _queues[dcId]);
-	});
-	const auto parts = data.maxWaitedAmount / kDownloadPartSize;
-	if (duration < kGrowMaxWaitedDurationThreshold * parts) {
-		if (data.maxWaitedAmount < kMaxWaitedInSession) {
-			data.maxWaitedAmount = std::min(
-				data.maxWaitedAmount + kDownloadPartSize,
-				kMaxWaitedInSession);
-			DEBUG_LOG(("Download (%1,%2) increased max waited amount %3."
-				).arg(dcId
-				).arg(index
-				).arg(data.maxWaitedAmount));
-		}
+	const auto overloaded = (timeAtRequestStart <= dc.lastSessionRemove)
+		|| (amountAtRequestStart > data.maxWaitedAmount);
+	const auto parts = amountAtRequestStart / kDownloadPartSize;
+	const auto duration = (crl::now() - timeAtRequestStart);
+	DEBUG_LOG(("Download (%1,%2) request done, duration: %3, parts: %4%5"
+		).arg(dcId
+		).arg(index
+		).arg(duration
+		).arg(parts
+		).arg(overloaded ? " (overloaded)" : ""));
+	if (overloaded) {
+		return;
 	}
-	if (duration >= kBadRequestDurationThreshold * parts) {
+
+	if (duration >= kBadRequestDurationThreshold) {
 		DEBUG_LOG(("Duration too large, signaling time out."));
 		sessionTimedOut(dcId, index);
 		return;
-	} else if (duration >= kGrowSessionsDurationThreshold * parts) {
-		return;
+	}
+	if (amountAtRequestStart == data.maxWaitedAmount
+		&& data.maxWaitedAmount < kMaxWaitedInSession) {
+		data.maxWaitedAmount = std::min(
+			data.maxWaitedAmount + kDownloadPartSize,
+			kMaxWaitedInSession);
+		DEBUG_LOG(("Download (%1,%2) increased max waited amount %3."
+			).arg(dcId
+			).arg(index
+			).arg(data.maxWaitedAmount));
 	}
 	data.successes = std::min(data.successes + 1, kMaxTrackedSuccesses);
 	const auto notEnough = ranges::find_if(
@@ -247,10 +261,22 @@ void DownloadManagerMtproto::requestSucceeded(
 	if (dc.lastSessionRemove && now < dc.lastSessionRemove + delay) {
 		return;
 	}
-	DEBUG_LOG(("Download (%1,%2) added session."
-		).arg(dcId
-		).arg(dc.sessions.size()));
 	dc.sessions.emplace_back();
+	DEBUG_LOG(("Download (%1,%2) adding, now sessions: %3"
+		).arg(dcId
+		).arg(dc.sessions.size() - 1
+		).arg(dc.sessions.size()));
+}
+
+int DownloadManagerMtproto::chooseSessionIndex(MTP::DcId dcId) const {
+	const auto i = _balanceData.find(dcId);
+	Assert(i != end(_balanceData));
+	const auto &sessions = i->second.sessions;
+	const auto j = ranges::min_element(
+		sessions,
+		ranges::less(),
+		&DcSessionBalanceData::requested);
+	return (j - begin(sessions));
 }
 
 void DownloadManagerMtproto::sessionTimedOut(MTP::DcId dcId, int index) {
@@ -278,7 +304,10 @@ void DownloadManagerMtproto::removeSession(MTP::DcId dcId) {
 	auto &dc = _balanceData[dcId];
 	Assert(dc.sessions.size() > kStartSessionsCount);
 	const auto index = int(dc.sessions.size() - 1);
-	DEBUG_LOG(("Download (%1,%2) removing session.").arg(dcId).arg(index));
+	DEBUG_LOG(("Download (%1,%2) removing, now sessions: %3"
+		).arg(dcId
+		).arg(index
+		).arg(index));
 	auto &queue = _queues[dcId];
 	if (dc.sessionRemoveIndex == index) {
 		dc.sessionRemoveTimes = std::min(
@@ -288,8 +317,17 @@ void DownloadManagerMtproto::removeSession(MTP::DcId dcId) {
 		dc.sessionRemoveIndex = index;
 		dc.sessionRemoveTimes = 1;
 	}
+	auto &session = dc.sessions.back();
+
+	// Make sure we don't send anything to that session while redirecting.
+	session.requested += kMaxWaitedInSession * kMaxSessionsCount;
+	_queues[dcId].removeSession(index);
+	Assert(session.requested == kMaxWaitedInSession * kMaxSessionsCount);
+
+	dc.sessions.pop_back();
+	MTP::killSession(MTP::downloadDcId(dcId, index));
+
 	dc.lastSessionRemove = crl::now();
-//	dc.sessions.pop_back();
 }
 
 void DownloadManagerMtproto::killSessionsSchedule(MTP::DcId dcId) {
@@ -406,16 +444,37 @@ void DownloadMtprotoTask::refreshFileReferenceFrom(
 	}
 }
 
-void DownloadMtprotoTask::loadPart(int dcIndex) {
-	makeRequest({ takeNextRequestOffset(), dcIndex });
+void DownloadMtprotoTask::loadPart(int sessionIndex) {
+	makeRequest({ takeNextRequestOffset(), sessionIndex });
 }
 
-mtpRequestId DownloadMtprotoTask::sendRequest(const RequestData &requestData) {
+void DownloadMtprotoTask::removeSession(int sessionIndex) {
+	struct Redirect {
+		mtpRequestId requestId = 0;
+		int offset = 0;
+	};
+	auto redirect = std::vector<Redirect>();
+	for (const auto &[requestId, requestData] : _sentRequests) {
+		if (requestData.sessionIndex == sessionIndex) {
+			redirect.reserve(_sentRequests.size());
+			redirect.push_back({ requestId, requestData.offset });
+		}
+	}
+	for (const auto &[requestId, offset] : redirect) {
+		cancelRequest(requestId);
+		const auto newIndex = _owner->chooseSessionIndex(dcId());
+		Assert(newIndex < sessionIndex);
+		makeRequest({ offset, newIndex });
+	}
+}
+
+mtpRequestId DownloadMtprotoTask::sendRequest(
+		const RequestData &requestData) {
 	const auto offset = requestData.offset;
 	const auto limit = Storage::kDownloadPartSize;
 	const auto shiftedDcId = MTP::downloadDcId(
 		_cdnDcId ? _cdnDcId : dcId(),
-		requestData.dcIndex);
+		requestData.sessionIndex);
 	if (_cdnDcId) {
 		return api().request(MTPupload_GetCdnFile(
 			MTP_bytes(_cdnToken),
@@ -488,7 +547,7 @@ void DownloadMtprotoTask::requestMoreCdnFileHashes() {
 	const auto requestData = _cdnUncheckedParts.cbegin()->first;
 	const auto shiftedDcId = MTP::downloadDcId(
 		dcId(),
-		requestData.dcIndex);
+		requestData.sessionIndex);
 	_cdnHashesRequestId = api().request(MTPupload_GetCdnFileHashes(
 		MTP_bytes(_cdnToken),
 		MTP_int(requestData.offset)
@@ -533,7 +592,7 @@ void DownloadMtprotoTask::cdnPartLoaded(const MTPupload_CdnFile &result, mtpRequ
 			FinishRequestReason::Redirect);
 		const auto shiftedDcId = MTP::downloadDcId(
 			dcId(),
-			requestData.dcIndex);
+			requestData.sessionIndex);
 		const auto requestId = api().request(MTPupload_ReuploadCdnFile(
 			MTP_bytes(_cdnToken),
 			data.vrequest_token()
@@ -665,15 +724,16 @@ void DownloadMtprotoTask::getCdnFileHashesDone(
 void DownloadMtprotoTask::placeSentRequest(
 		mtpRequestId requestId,
 		const RequestData &requestData) {
-	_owner->changeRequestedAmount(
+	const auto amount = _owner->changeRequestedAmount(
 		dcId(),
-		requestData.dcIndex,
+		requestData.sessionIndex,
 		Storage::kDownloadPartSize);
 	const auto [i, ok1] = _sentRequests.emplace(requestId, requestData);
 	const auto [j, ok2] = _requestByOffset.emplace(
 		requestData.offset,
 		requestId);
 
+	i->second.requestedInSession = amount;
 	i->second.sent = crl::now();
 
 	Ensures(ok1 && ok2);
@@ -692,14 +752,17 @@ auto DownloadMtprotoTask::finishSentRequest(
 	const auto result = it->second;
 	_owner->changeRequestedAmount(
 		dcId(),
-		result.dcIndex,
+		result.sessionIndex,
 		-Storage::kDownloadPartSize);
 	_sentRequests.erase(it);
 	const auto ok = _requestByOffset.remove(result.offset);
 
 	if (reason == FinishRequestReason::Success) {
-		const auto duration = crl::now() - result.sent;
-		_owner->requestSucceeded(dcId(), result.dcIndex, duration);
+		_owner->requestSucceeded(
+			dcId(),
+			result.sessionIndex,
+			result.requestedInSession,
+			result.sent);
 	}
 
 	Ensures(ok);
@@ -731,10 +794,16 @@ void DownloadMtprotoTask::cancelRequestForOffset(int offset) {
 }
 
 void DownloadMtprotoTask::cancelRequest(mtpRequestId requestId) {
+	const auto hashes = (_cdnHashesRequestId == requestId);
 	api().request(requestId).cancel();
 	[[maybe_unused]] const auto data = finishSentRequest(
 		requestId,
 		FinishRequestReason::Cancel);
+	if (hashes && !_cdnUncheckedParts.empty()) {
+		crl::on_main(this, [=] {
+			requestMoreCdnFileHashes();
+		});
+	}
 }
 
 void DownloadMtprotoTask::addToQueue() {
diff --git a/Telegram/SourceFiles/storage/download_manager_mtproto.h b/Telegram/SourceFiles/storage/download_manager_mtproto.h
index 01629a1f1..2a7a0bff8 100644
--- a/Telegram/SourceFiles/storage/download_manager_mtproto.h
+++ b/Telegram/SourceFiles/storage/download_manager_mtproto.h
@@ -42,8 +42,13 @@ public:
 		return _taskFinishedObservable;
 	}
 
-	void changeRequestedAmount(MTP::DcId dcId, int index, int delta);
-	void requestSucceeded(MTP::DcId dcId, int index, crl::time duration);
+	int changeRequestedAmount(MTP::DcId dcId, int index, int delta);
+	void requestSucceeded(
+		MTP::DcId dcId,
+		int index,
+		int amountAtRequestStart,
+		crl::time timeAtRequestStart);
+	[[nodiscard]] int chooseSessionIndex(MTP::DcId dcId) const;
 
 private:
 	class Queue final {
@@ -53,6 +58,7 @@ private:
 		void resetGeneration();
 		[[nodiscard]] bool empty() const;
 		[[nodiscard]] Task *nextTask() const;
+		void removeSession(int index);
 
 	private:
 		std::vector<not_null<Task*>> _tasks;
@@ -129,7 +135,8 @@ public:
 	[[nodiscard]] const Location &location() const;
 
 	[[nodiscard]] virtual bool readyToRequest() const = 0;
-	void loadPart(int dcIndex);
+	void loadPart(int sessionIndex);
+	void removeSession(int sessionIndex);
 
 	void refreshFileReferenceFrom(
 		const Data::UpdatedFileReferences &updates,
@@ -152,7 +159,8 @@ protected:
 private:
 	struct RequestData {
 		int offset = 0;
-		int dcIndex = 0;
+		int sessionIndex = 0;
+		int requestedInSession = 0;
 		crl::time sent = 0;
 
 		inline bool operator<(const RequestData &other) const {