Don't unload all media on switching between chats.

Telegram/SourceFiles/data/data_document.cpp

@@ -34,7 +34,7 @@ constexpr auto kMemoryForCache = 32 * 1024 * 1024;
 Core::MediaActiveCache<DocumentData> &ActiveCache() {
 	static auto Instance = Core::MediaActiveCache<DocumentData>(
 		kMemoryForCache,
-		[](DocumentData *document) { document->forget(); });
+		[](DocumentData *document) { document->unload(); });
 	return Instance;
 }
 
@@ -536,7 +536,9 @@ bool DocumentData::saveToCache() const {
 		|| (isVoiceMessage() && size < Storage::kMaxVoiceInMemory);
 }
 
-void DocumentData::forget() {
+void DocumentData::unload() {
+	// Forget thumb only when image cache limit exceeds.
+	//thumb->unload();
 	if (sticker()) {
 		if (!sticker()->img->isNull()) {
 			ActiveCache().decrement(ComputeUsage(sticker()));
@@ -551,6 +553,7 @@ void DocumentData::forget() {
 		delete replyPreview.get();
 		replyPreview = ImagePtr();
 	}
+
 	ActiveCache().decrement(_data.size());
 	_data.clear();
 }

Telegram/SourceFiles/data/data_document.h

@@ -121,7 +121,7 @@ public:
 
 	void performActionOnLoad();
 
-	void forget();
+	void unload();
 	ImagePtr makeReplyPreview(Data::FileOrigin origin);
 
 	StickerData *sticker() const;

Telegram/SourceFiles/data/data_game.h

@@ -30,11 +30,6 @@ struct GameData {
 	, document(document) {
 	}
 
-	void forget() {
-		if (document) document->forget();
-		if (photo) photo->forget();
-	}
-
 	GameId id = 0;
 	uint64 accessHash = 0;
 	QString shortName;

Telegram/SourceFiles/data/data_photo.cpp

@@ -103,15 +103,16 @@ bool PhotoData::uploading() const {
 	return (uploadingData != nullptr);
 }
 
-void PhotoData::forget() {
-	thumb->forget();
+void PhotoData::unload() {
+	// Forget thumb only when image cache limit exceeds.
+	//thumb->unload();
+	medium->unload();
+	full->unload();
 	if (!replyPreview->isNull()) {
 		// Should be std::unique_ptr<Image>.
 		delete replyPreview.get();
 		replyPreview = ImagePtr();
 	}
-	medium->forget();
-	full->forget();
 }
 
 ImagePtr PhotoData::makeReplyPreview(Data::FileOrigin origin) {

Telegram/SourceFiles/data/data_photo.h

@@ -38,7 +38,7 @@ public:
 	void setWaitingForAlbum();
 	bool waitingForAlbum() const;
 
-	void forget();
+	void unload();
 	ImagePtr makeReplyPreview(Data::FileOrigin origin);
 
 	MTPInputPhoto mtpInput() const;

Telegram/SourceFiles/data/data_session.cpp

@@ -2008,18 +2008,6 @@ void Session::insertCheckedServiceNotification(
 	sendHistoryChangeNotifications();
 }
 
-void Session::forgetMedia() {
-	for (const auto &[id, photo] : _photos) {
-		photo->forget();
-	}
-	for (const auto &[id, document] : _documents) {
-		document->forget();
-	}
-	for (const auto &[coords, location] : _locations) {
-		location->thumb->forget();
-	}
-}
-
 void Session::setMimeForwardIds(MessageIdsList &&list) {
 	_mimeForwardIds = std::move(list);
 }

Telegram/SourceFiles/data/data_session.h

@@ -420,8 +420,6 @@ public:
 		const TextWithEntities &message,
 		const MTPMessageMedia &media = MTP_messageMediaEmpty());
 
-	void forgetMedia();
-
 	void setMimeForwardIds(MessageIdsList &&list);
 	MessageIdsList takeMimeForwardIds();
 

Telegram/SourceFiles/data/data_web_page.h

@@ -54,11 +54,6 @@ struct WebPageData {
 	, pendingTill(pendingTill) {
 	}
 
-	void forget() {
-		if (document) document->forget();
-		if (photo) photo->forget();
-	}
-
 	bool applyChanges(
 		const QString &newType,
 		const QString &newUrl,