Enable messages unpinning for channels

Also make History Widget react on pinning Channel message event and show
it in UI.

This commit is based on upstream commit
75d8d01b17

Related to #114.
Closes #8.

Telegram/SourceFiles/history/history_inner_widget.cpp

@@ -1240,9 +1240,9 @@ void HistoryInner::showContextMenu(QContextMenuEvent *e, bool showFromTouch) {
 				_menu->addAction(lang(lng_context_edit_msg), _widget, SLOT(onEditMessage()));
 			}
 			if (item->canPin()) {
-				bool ispinned = (item->history()->peer->asChannel()->pinnedMessageId() == item->id);
+				bool isPinned = item->isPinned();
-				_menu->addAction(lang(ispinned ? lng_context_unpin_msg : lng_context_pin_msg), _widget,
+				_menu->addAction(lang(isPinned ? lng_context_unpin_msg : lng_context_pin_msg), _widget,
-				                 ispinned ? SLOT(onUnpinMessage()) : SLOT(onPinMessage()));
+				                 isPinned ? SLOT(onUnpinMessage()) : SLOT(onPinMessage()));
 			}
 		}
 		if (lnkPhoto) {

Telegram/SourceFiles/history/history_item.cpp

@@ -822,6 +822,13 @@ void HistoryItem::setId(MsgId newId) {
 	}
 }
 
+bool HistoryItem::isPinned() const {
+	if (auto channel = _history->peer->asChannel()) {
+		return (channel->pinnedMessageId() == id);
+	}
+	return false;
+}
+
 bool HistoryItem::canPin() const {
 	if (id < 0 || !toHistoryMessage()) {
 		return false;

Telegram/SourceFiles/history/history_item.h

@@ -717,6 +717,7 @@ public:
 		return _text.isEmpty();
 	}
 
+	bool isPinned() const;
 	bool canPin() const;
 	bool canForward() const;
 	bool canEdit(const QDateTime &cur) const;

Telegram/SourceFiles/history/history_widget.cpp

@@ -5992,23 +5992,19 @@ void HistoryWidget::onEditMessage() {
 }
 
 void HistoryWidget::onPinMessage() {
-	HistoryItem *to = App::contextItem();
+	auto to = App::contextItem();
-	if (!to || !to->canPin() || !_peer || !_peer->isMegagroup()) return;
+	if (!to || !to->canPin()) return;
 
 	Ui::show(Box<PinMessageBox>(_peer->asChannel(), to->id));
 }
 
 void HistoryWidget::onUnpinMessage() {
-	if (!_peer || !_peer->isMegagroup()) return;
+	if (!_peer || !_peer->isChannel()) return;
 
 	Ui::show(Box<ConfirmBox>(lang(lng_pinned_unpin_sure), lang(lng_pinned_unpin), base::lambda_guarded(this, [this] {
-		                         if (!_peer || !_peer->asChannel()) return;
+		                         auto channel = _peer ? _peer->asChannel() : nullptr;
-
+		                         if (!channel) return;
-		                         _peer->asChannel()->clearPinnedMessage();
+		                         channel->clearPinnedMessage();
-		                         if (pinnedMsgVisibilityUpdated()) {
-			                         updateControlsGeometry();
-			                         update();
-		                         }
 
 		                         Ui::hideLayer();
 		                         MTP::send(MTPchannels_UpdatePinnedMessage(
@@ -6024,8 +6020,10 @@ void HistoryWidget::unpinDone(const MTPUpdates &updates) {
 }
 
 void HistoryWidget::onPinnedHide() {
-	if (!_peer || !_peer->asChannel()) return;
+	auto channel = _peer ? _peer->asChannel() : nullptr;
-	if (!_peer->asChannel()->pinnedMessageId()) {
+	if (!channel) return;
+	auto pinnedId = channel->pinnedMessageId();
+	if (!pinnedId) {
 		if (pinnedMsgVisibilityUpdated()) {
 			updateControlsGeometry();
 			update();
@@ -6033,10 +6031,10 @@ void HistoryWidget::onPinnedHide() {
 		return;
 	}
 
-	if (_peer->asChannel()->canPinMessages()) {
+	if (channel->canPinMessages()) {
 		onUnpinMessage();
 	} else {
-		Global::RefHiddenPinnedMessages().insert(_peer->id, _peer->asChannel()->pinnedMessageId());
+		Global::RefHiddenPinnedMessages().insert(_peer->id, pinnedId);
 		Local::writeUserSettings();
 		if (pinnedMsgVisibilityUpdated()) {
 			updateControlsGeometry();