From 456a949d0129a945c1b2c46a26f3253a977167d6 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Thu, 4 Apr 2019 00:05:29 +0400
Subject: [PATCH] Fix working with document thumbnails.

---
 Telegram/SourceFiles/storage/localstorage.cpp    | 11 ++++++++++-
 .../SourceFiles/storage/serialize_document.cpp   | 16 ++++++++--------
 Telegram/SourceFiles/ui/image/image_location.cpp | 16 ++++++++--------
 Telegram/SourceFiles/ui/image/image_location.h   |  3 +++
 4 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/Telegram/SourceFiles/storage/localstorage.cpp b/Telegram/SourceFiles/storage/localstorage.cpp
index 5e9750a59..398d5c662 100644
--- a/Telegram/SourceFiles/storage/localstorage.cpp
+++ b/Telegram/SourceFiles/storage/localstorage.cpp
@@ -4009,6 +4009,11 @@ void readSavedGifs() {
 	}
 
 	auto &saved = Auth().data().savedGifsRef();
+	const auto failed = [&] {
+		clearKey(_savedGifsKey);
+		_savedGifsKey = 0;
+		saved.clear();
+	};
 	saved.clear();
 
 	quint32 cnt;
@@ -4017,7 +4022,11 @@ void readSavedGifs() {
 	OrderedSet<DocumentId> read;
 	for (uint32 i = 0; i < cnt; ++i) {
 		auto document = Serialize::Document::readFromStream(gifs.version, gifs.stream);
-		if (!document || !document->isGifv()) continue;
+		if (!_checkStreamStatus(gifs.stream)) {
+			return failed();
+		} else if (!document || !document->isGifv()) {
+			continue;
+		}
 
 		if (read.contains(document->id)) continue;
 		read.insert(document->id);
diff --git a/Telegram/SourceFiles/storage/serialize_document.cpp b/Telegram/SourceFiles/storage/serialize_document.cpp
index 86eef5dba..dff29af5f 100644
--- a/Telegram/SourceFiles/storage/serialize_document.cpp
+++ b/Telegram/SourceFiles/storage/serialize_document.cpp
@@ -131,14 +131,14 @@ DocumentData *Document::readFromStreamHelper(int streamAppVersion, QDataStream &
 		}
 	}
 
-	if ((!dc && !access) || !thumb) {
+	if ((!dc && !access)
+		|| !thumb
+		|| (thumb->valid() && !thumb->file().isDocumentThumbnail())) {
+		stream.setStatus(QDataStream::ReadCorruptData);
+		// We can't convert legacy thumbnail location to modern, because
+		// size letter ('s' or 'm') is lost, it was not saved in legacy.
 		return nullptr;
 	}
-	using LocationType = StorageFileLocation::Type;
-	const auto location = (thumb->valid()
-		&& thumb->type() == LocationType::Legacy)
-		? thumb->convertToModern(LocationType::Document, id, access)
-		: *thumb;
 	return Auth().data().document(
 		id,
 		access,
@@ -147,10 +147,10 @@ DocumentData *Document::readFromStreamHelper(int streamAppVersion, QDataStream &
 		attributes,
 		mime,
 		ImagePtr(),
-		Images::Create(location),
+		Images::Create(*thumb),
 		dc,
 		size,
-		location);
+		*thumb);
 }
 
 DocumentData *Document::readStickerFromStream(int streamAppVersion, QDataStream &stream, const StickerSetInfo &info) {
diff --git a/Telegram/SourceFiles/ui/image/image_location.cpp b/Telegram/SourceFiles/ui/image/image_location.cpp
index 7c91b971c..8ae994e61 100644
--- a/Telegram/SourceFiles/ui/image/image_location.cpp
+++ b/Telegram/SourceFiles/ui/image/image_location.cpp
@@ -134,9 +134,7 @@ StorageFileLocation StorageFileLocation::convertToModern(
 		uint64 id,
 		uint64 accessHash) const {
 	Expects(_type == Type::Legacy);
-	Expects(type == Type::Document
-		|| type == Type::PeerPhoto
-		|| type == Type::StickerSetThumb);
+	Expects(type == Type::PeerPhoto || type == Type::StickerSetThumb);
 
 	auto result = *this;
 	result._type = type;
@@ -305,10 +303,15 @@ bool StorageFileLocation::valid() const {
 	return false;
 }
 
+bool StorageFileLocation::isDocumentThumbnail() const {
+	return (_type == Type::Document) && (_sizeLetter != 0);
+}
+
 Storage::Cache::Key StorageFileLocation::cacheKey() const {
 	using Key = Storage::Cache::Key;
 
-	// Skip '1' and '2' for legacy document cache keys.
+	// Skip '1' for legacy document cache keys.
+	// Skip '2' because it is used for good (fullsize) document thumbnails.
 	const auto shifted = ((uint64(_type) + 3) << 8);
 	const auto sliced = uint64(_dcId) & 0xFFULL;
 	switch (_type) {
@@ -324,13 +327,10 @@ Storage::Cache::Key StorageFileLocation::cacheKey() const {
 		return Key{ shifted | sliced, _id };
 
 	case Type::Document:
-		// Keep old cache keys for documents and document 'm' thumbnails.
+		// Keep old cache keys for documents.
 		if (_sizeLetter == 0) {
 			return Data::DocumentCacheKey(_dcId, _id);
 			//return Key{ 0x100ULL | sliced, _id };
-		} else if (_sizeLetter == uint8('m')) {
-			return Data::DocumentThumbCacheKey(_dcId, _id);
-			//return Key{ 0x200ULL | sliced, _id };
 		}
 		[[fallthrough]];
 	case Type::Photo:
diff --git a/Telegram/SourceFiles/ui/image/image_location.h b/Telegram/SourceFiles/ui/image/image_location.h
index 814ff41b2..1527459be 100644
--- a/Telegram/SourceFiles/ui/image/image_location.h
+++ b/Telegram/SourceFiles/ui/image/image_location.h
@@ -86,6 +86,9 @@ public:
 	[[nodiscard]] Storage::Cache::Key cacheKey() const;
 	[[nodiscard]] Storage::Cache::Key bigFileBaseCacheKey() const;
 
+	// We have to allow checking this because of a serialization bug.
+	[[nodiscard]] bool isDocumentThumbnail() const;
+
 	[[nodiscard]] QByteArray fileReference() const;
 	bool refreshFileReference(const Data::UpdatedFileReferences &updates);
 	bool refreshFileReference(const QByteArray &data);