From 61700577d0f857148f372aba12f0005f29f86c49 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 8 Mar 2018 13:47:31 +0300
Subject: [PATCH] Fix possible crash with invalidated views.

---
 .../history/history_inner_widget.cpp          | 24 +++++++++++++++++++
 .../history/history_inner_widget.h            |  1 +
 .../SourceFiles/history/history_widget.cpp    |  4 ----
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/Telegram/SourceFiles/history/history_inner_widget.cpp b/Telegram/SourceFiles/history/history_inner_widget.cpp
index b7e25c257..e4e914333 100644
--- a/Telegram/SourceFiles/history/history_inner_widget.cpp
+++ b/Telegram/SourceFiles/history/history_inner_widget.cpp
@@ -139,6 +139,10 @@ HistoryInner::HistoryInner(
 	) | rpl::start_with_next(
 		[this](auto item) { itemRemoved(item); },
 		lifetime());
+	Auth().data().itemViewRefreshRequest(
+	) | rpl::start_with_next([this](auto item) {
+		refreshView(item);
+	}, lifetime());
 	rpl::merge(
 		Auth().data().historyUnloaded(),
 		Auth().data().historyCleared()
@@ -1212,9 +1216,29 @@ void HistoryInner::itemRemoved(not_null<const HistoryItem*> item) {
 		_dragSelTo = nullptr;
 		update();
 	}
+	if (_scrollDateLastItem && _scrollDateLastItem->data() == item) {
+		_scrollDateLastItem = nullptr;
+	}
 	mouseActionUpdate();
 }
 
+void HistoryInner::refreshView(not_null<HistoryItem*> item) {
+	const auto dragSelFrom = (_dragSelFrom && _dragSelFrom->data() == item);
+	const auto dragSelTo = (_dragSelTo && _dragSelTo->data() == item);
+	const auto scrollDateLastItem = (_scrollDateLastItem
+		&& _scrollDateLastItem->data() == item);
+	item->refreshMainView();
+	if (dragSelFrom) {
+		_dragSelFrom = item->mainView();
+	}
+	if (dragSelTo) {
+		_dragSelTo = item->mainView();
+	}
+	if (scrollDateLastItem) {
+		_scrollDateLastItem = item->mainView();
+	}
+}
+
 void HistoryInner::mouseActionFinish(
 		const QPoint &screenPos,
 		Qt::MouseButton button) {
diff --git a/Telegram/SourceFiles/history/history_inner_widget.h b/Telegram/SourceFiles/history/history_inner_widget.h
index 4134a5ecc..9f8487298 100644
--- a/Telegram/SourceFiles/history/history_inner_widget.h
+++ b/Telegram/SourceFiles/history/history_inner_widget.h
@@ -213,6 +213,7 @@ private:
 	void toggleFavedSticker(not_null<DocumentData*> document);
 
 	void itemRemoved(not_null<const HistoryItem*> item);
+	void refreshView(not_null<HistoryItem*> item);
 
 	void touchResetSpeed();
 	void touchUpdateSpeed();
diff --git a/Telegram/SourceFiles/history/history_widget.cpp b/Telegram/SourceFiles/history/history_widget.cpp
index e80a1cb0b..180631c95 100644
--- a/Telegram/SourceFiles/history/history_widget.cpp
+++ b/Telegram/SourceFiles/history/history_widget.cpp
@@ -573,10 +573,6 @@ HistoryWidget::HistoryWidget(
 			updateHistoryGeometry();
 		}
 	}, lifetime());
-	Auth().data().itemViewRefreshRequest(
-	) | rpl::start_with_next([this](auto item) {
-		item->refreshMainView();
-	}, lifetime());
 	Auth().data().animationPlayInlineRequest(
 	) | rpl::start_with_next([this](auto item) {
 		if (const auto view = item->mainView()) {