Differ file download failure reasons

..and uncomment the code for handling incorrect permissions

Telegram/Resources/langs/lang.strings

@@ -762,7 +762,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_download_path_dir_radio" = "Custom folder, cleared only manually";
 "lng_download_path_choose" = "Choose download path";
 "lng_sure_clear_downloads" = "Do you want to remove all downloaded files from temp folder? It is done automatically on logout or program uninstall.";
-"lng_download_path_failed" = "File download could not be started.\n\nThis might be because the download location you've selected is invalid. Try changing the \"Download path\" in Settings.";
+"lng_download_path_failed" = "File download could not be started.\n\nThe default download location will be used now. You can always change it in Settings > Advanced > Download Path.\n\nPlease try once again.";
 "lng_download_path_settings" = "Settings";
 "lng_download_finish_failed" = "File download could not be finished.\n\nWould you like to try again?";
 "lng_download_path_clearing" = "Clearing...";

Telegram/SourceFiles/data/data_cloud_file.cpp

@@ -279,11 +279,11 @@ void LoadCloudFile(
 		if (const auto onstack = progress) {
 			onstack();
 		}
-	}, [=, &file](bool started) {
+	}, [=, &file](FileLoader::Error error) {
 		finish(file);
 		file.flags |= CloudFile::Flag::Failed;
 		if (const auto onstack = fail) {
-			onstack(started);
+			onstack(error.started);
 		}
 	}, [=, &file] {
 		finish(file);

Telegram/SourceFiles/data/data_document.cpp

@@ -988,8 +988,9 @@ void DocumentData::handleLoaderUpdates() {
 	_loader->updates(
 	) | rpl::start_with_next_error_done([=] {
 		_owner->documentLoadProgress(this);
-	}, [=](bool started) {
-		if (started && _loader) {
+	}, [=](FileLoader::Error error) {
+		using FailureReason = FileLoader::FailureReason;
+		if (error.started && _loader) {
 			const auto origin = _loader->fileOrigin();
 			const auto failedFileName = _loader->fileName();
 			const auto retry = [=] {
@@ -1000,23 +1001,21 @@ void DocumentData::handleLoaderUpdates() {
 				tr::lng_download_finish_failed(),
 				crl::guard(&session(), retry)
 			}));
-		} else {
-			// Sometimes we have LOCATION_INVALID error in documents / stickers.
-			// Sometimes FILE_REFERENCE_EXPIRED could not be handled.
-			//
-			//const auto openSettings = [=] {
-			//	Core::App().settings().etDownloadPathBookmark(QByteArray());
-			//	Core::App().settings().setDownloadPath(QString());
-			//	Ui::show(Box<DownloadPathBox>());
-			//};
-			//Ui::show(Box<Ui::ConfirmBox>(
-			//	tr::lng_download_path_failed(tr::now),
-			//	tr::lng_download_path_settings(tr::now),
-			//	crl::guard(&session(), openSettings)));
+		} else if (error.failureReason == FailureReason::FileWriteFailure) {
+			if (!Core::App().settings().downloadPath().isEmpty()) {
+				Core::App().settings().setDownloadPathBookmark(QByteArray());
+				Core::App().settings().setDownloadPath(QString());
+				Core::App().saveSettingsDelayed();
+				InvokeQueued(qApp, [] {
+					Ui::show(
+						Ui::MakeInformBox(
+							tr::lng_download_path_failed(tr::now)));
+				});
+			}
 		}
 		finishLoad();
 		status = FileDownloadFailed;
-		_owner->documentLoadFail(this, started);
+		_owner->documentLoadFail(this, error.started);
 	}, [=] {
 		finishLoad();
 		_owner->documentLoadDone(this);

Telegram/SourceFiles/passport/passport_form_controller.cpp

@@ -1816,7 +1816,7 @@ void FormController::loadFile(File &file) {
 	loader->updates(
 	) | rpl::start_with_next_error_done([=] {
 		fileLoadProgress(key, loader->currentOffset());
-	}, [=](bool started) {
+	}, [=](FileLoader::Error error) {
 		fileLoadFail(key);
 	}, [=] {
 		fileLoadDone(key, loader->bytes());

Telegram/SourceFiles/storage/file_download.cpp

@@ -128,12 +128,12 @@ void FileLoader::finishWithBytes(const QByteArray &data) {
 	if (!_filename.isEmpty() && _toCache == LoadToCacheAsWell) {
 		if (!_fileIsOpen) _fileIsOpen = _file.open(QIODevice::WriteOnly);
 		if (!_fileIsOpen) {
-			cancel(true);
+			cancel(FailureReason::FileWriteFailure);
 			return;
 		}
 		_file.seek(0);
 		if (_file.write(_data) != qint64(_data.size())) {
-			cancel(true);
+			cancel(FailureReason::FileWriteFailure);
 			return;
 		}
 	}
@@ -258,7 +258,7 @@ bool FileLoader::checkForOpen() {
 	if (_fileIsOpen) {
 		return true;
 	}
-	cancel(true);
+	cancel(FailureReason::FileWriteFailure);
 	return false;
 }
 
@@ -329,10 +329,10 @@ bool FileLoader::tryLoadLocal() {
 }
 
 void FileLoader::cancel() {
-	cancel(false);
+	cancel(FailureReason::NoFailure);
 }
 
-void FileLoader::cancel(bool fail) {
+void FileLoader::cancel(FailureReason fail) {
 	const auto started = (currentOffset() > 0);
 
 	cancelHook();
@@ -347,8 +347,8 @@ void FileLoader::cancel(bool fail) {
 	_data = QByteArray();
 
 	const auto weak = base::make_weak(this);
-	if (fail) {
-		_updates.fire_error_copy(started);
+	if (fail != FailureReason::NoFailure) {
+		_updates.fire_error_copy({ fail, started });
 	} else {
 		_updates.fire_done();
 	}
@@ -377,7 +377,7 @@ bool FileLoader::writeResultPart(int64 offset, bytes::const_span buffer) {
 		}
 		_file.seek(offset);
 		if (_file.write(reinterpret_cast<const char*>(buffer.data()), buffer.size()) != qint64(buffer.size())) {
-			cancel(true);
+			cancel(FailureReason::FileWriteFailure);
 			return false;
 		}
 		return true;
@@ -410,7 +410,7 @@ QByteArray FileLoader::readLoadedPartBack(int64 offset, int size) {
 			_file.close();
 			_fileIsOpen = _file.open(QIODevice::ReadWrite);
 			if (!_fileIsOpen) {
-				cancel(true);
+				cancel(FailureReason::FileWriteFailure);
 				return QByteArray();
 			}
 		}
@@ -434,7 +434,7 @@ bool FileLoader::finalizeResult() {
 		}
 		_file.seek(0);
 		if (!_fileIsOpen || _file.write(_data) != qint64(_data.size())) {
-			cancel(true);
+			cancel(FailureReason::FileWriteFailure);
 			return false;
 		}
 	}

Telegram/SourceFiles/storage/file_download.h

@@ -52,6 +52,17 @@ struct StorageImageSaved {
 
 class FileLoader : public base::has_weak_ptr {
 public:
+	enum class FailureReason {
+		NoFailure,
+		FileWriteFailure,
+		OtherFailure,
+	};
+
+	struct Error {
+		FailureReason failureReason = FailureReason::NoFailure;
+		bool started = false;
+	};
+
 	FileLoader(
 		not_null<Main::Session*> session,
 		const QString &toFile,
@@ -113,7 +124,7 @@ public:
 		const QByteArray &imageFormat,
 		const QImage &imageData);
 
-	[[nodiscard]] rpl::producer<rpl::empty_value, bool> updates() const {
+	[[nodiscard]] rpl::producer<rpl::empty_value, Error> updates() const {
 		return _updates.events();
 	}
 
@@ -142,7 +153,7 @@ protected:
 		startLoading();
 	}
 
-	void cancel(bool failed);
+	void cancel(FailureReason failed);
 
 	void notifyAboutProgress();
 
@@ -177,7 +188,7 @@ protected:
 	mutable QImage _imageData;
 
 	rpl::lifetime _lifetime;
-	rpl::event_stream<rpl::empty_value, bool> _updates;
+	rpl::event_stream<rpl::empty_value, Error> _updates;
 
 };
 

Telegram/SourceFiles/storage/file_download_mtproto.cpp

@@ -164,7 +164,7 @@ bool mtpFileLoader::feedPart(int64 offset, const QByteArray &bytes) {
 }
 
 void mtpFileLoader::cancelOnFail() {
-	cancel(true);
+	cancel(FailureReason::OtherFailure);
 }
 
 bool mtpFileLoader::setWebFileSizeHook(int64 size) {
@@ -176,7 +176,7 @@ bool mtpFileLoader::setWebFileSizeHook(int64 size) {
 		"Bad size provided by bot for webDocument: %1, real: %2"
 		).arg(_fullSize
 		).arg(size));
-	cancel(true);
+	cancel(FailureReason::OtherFailure);
 	return false;
 }
 

Telegram/SourceFiles/storage/file_download_web.cpp

@@ -506,7 +506,7 @@ void webFileLoader::loadFinished(const QByteArray &data) {
 }
 
 void webFileLoader::loadFailed() {
-	cancel(true);
+	cancel(FailureReason::OtherFailure);
 }
 
 Storage::Cache::Key webFileLoader::cacheKey() const {

Telegram/SourceFiles/storage/streamed_file_downloader.cpp

@@ -59,7 +59,7 @@ StreamedFileDownloader::StreamedFileDownloader(
 	_reader->partsForDownloader(
 	) | rpl::start_with_next([=](const LoadedPart &part) {
 		if (part.offset == LoadedPart::kFailedOffset) {
-			cancel(true);
+			cancel(FailureReason::OtherFailure);
 		} else {
 			savePart(std::move(part));
 		}