From 5feb381cb26fe4dda0e3438f4635e70ccf05fafe Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 1 Feb 2021 15:44:22 +0400
Subject: [PATCH] Allow showing images from cache in media viewer.

Fixes #10237.
---
 Telegram/SourceFiles/data/data_document.cpp   | 41 ++++++++++++++-----
 .../media/view/media_view_overlay_widget.cpp  | 16 +++++++-
 2 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/Telegram/SourceFiles/data/data_document.cpp b/Telegram/SourceFiles/data/data_document.cpp
index c241c6b244..6f0bcf47f7 100644
--- a/Telegram/SourceFiles/data/data_document.cpp
+++ b/Telegram/SourceFiles/data/data_document.cpp
@@ -47,6 +47,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "lottie/lottie_animation.h"
 #include "app.h"
 
+#include <QtCore/QBuffer>
+
 namespace {
 
 const auto kAnimatedStickerDimensions = QSize(
@@ -320,21 +322,33 @@ void DocumentOpenClickHandler::Open(
 		return;
 	}
 
-	const auto openFile = [&] {
+	const auto media = data->createMediaView();
+	const auto openImageInApp = [&] {
+		if (data->size >= App::kImageSizeLimit) {
+			return false;
+		}
 		const auto &location = data->location(true);
-		if (data->size < App::kImageSizeLimit && location.accessEnable()) {
+		if (!location.isEmpty() && location.accessEnable()) {
 			const auto guard = gsl::finally([&] {
 				location.accessDisable();
 			});
 			const auto path = location.name();
-			if (Core::MimeTypeForFile(path).name().startsWith("image/") && QImageReader(path).canRead()) {
+			if (Core::MimeTypeForFile(path).name().startsWith("image/")
+				&& QImageReader(path).canRead()) {
 				Core::App().showDocument(data, context);
-				return;
+				return true;
+			}
+		} else if (data->mimeString().startsWith("image/")
+			&& !media->bytes().isEmpty()) {
+			auto bytes = media->bytes();
+			auto buffer = QBuffer(&bytes);
+			if (QImageReader(&buffer).canRead()) {
+				Core::App().showDocument(data, context);
+				return true;
 			}
 		}
-		LaunchWithWarning(&data->session(), location.name(), context);
+		return false;
 	};
-	const auto media = data->createMediaView();
 	const auto &location = data->location(true);
 	if (data->isTheme() && media->loaded(true)) {
 		Core::App().showDocument(data, context);
@@ -352,11 +366,16 @@ void DocumentOpenClickHandler::Open(
 		} else {
 			Core::App().showDocument(data, context);
 		}
-	} else if (data->saveFromDataSilent()) {
-		openFile();
-	} else if (data->status == FileReady
-		|| data->status == FileDownloadFailed) {
-		DocumentSaveClickHandler::Save(origin, data);
+	} else {
+		data->saveFromDataSilent();
+		if (!openImageInApp()) {
+			if (!data->filepath(true).isEmpty()) {
+				LaunchWithWarning(&data->session(), location.name(), context);
+			} else if (data->status == FileReady
+				|| data->status == FileDownloadFailed) {
+				DocumentSaveClickHandler::Save(origin, data);
+			}
+		}
 	}
 }
 
diff --git a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
index f16fde906d..f2088909c9 100644
--- a/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
+++ b/Telegram/SourceFiles/media/view/media_view_overlay_widget.cpp
@@ -197,8 +197,7 @@ void PaintImageProfile(QPainter &p, const QImage &image, QRect rect, QRect fill)
 	});
 }
 
-QPixmap PrepareStaticImage(const QString &path) {
-	auto image = App::readImage(path, nullptr, false);
+QPixmap PrepareStaticImage(QImage image) {
 #if defined Q_OS_MAC && !defined OS_MAC_OLD
 	if (image.width() > kMaxDisplayImageSize
 		|| image.height() > kMaxDisplayImageSize) {
@@ -212,6 +211,14 @@ QPixmap PrepareStaticImage(const QString &path) {
 	return App::pixmapFromImageInPlace(std::move(image));
 }
 
+QPixmap PrepareStaticImage(const QString &path) {
+	return PrepareStaticImage(App::readImage(path, nullptr, false));
+}
+
+QPixmap PrepareStaticImage(const QByteArray &bytes) {
+	return PrepareStaticImage(App::readImage(bytes, nullptr, false));
+}
+
 } // namespace
 
 struct OverlayWidget::SharedMedia {
@@ -2304,6 +2311,11 @@ void OverlayWidget::displayDocument(
 						_staticContent = PrepareStaticImage(path);
 						_touchbarDisplay.fire(TouchBarItemType::Photo);
 					}
+				} else if (!_documentMedia->bytes().isEmpty()) {
+					_staticContent = PrepareStaticImage(_documentMedia->bytes());
+					if (!_staticContent.isNull()) {
+						_touchbarDisplay.fire(TouchBarItemType::Photo);
+					}
 				}
 				location.accessDisable();
 			}