CLOUD: Add SavesSyncRequest sketch

Never tested it, actually. It requires Storage to implement upload()
method and me to find some way to get saves' ReadStream.

The saveTimestamps() and loadTimestamps() part should be tested, other
parts should work fine.

1 files changed, 229 insertions, 0 deletions

diff --git a/backends/cloud/savessyncrequest.cpp b/backends/cloud/savessyncrequest.cpp
new file mode 100644
index 0000000000..d48ec6ba45
--- /dev/null
+++ b/backends/cloud/savessyncrequest.cpp
@@ -0,0 +1,229 @@
+/* ScummVM - Graphic Adventure Engine
+*
+* ScummVM is the legal property of its developers, whose names
+* are too numerous to list here. Please refer to the COPYRIGHT
+* file distributed with this source distribution.
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version 2
+* of the License, or (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+*
+*/
+
+#include "backends/cloud/savessyncrequest.h"
+#include "common/debug.h"
+#include "common/file.h"
+
+namespace Cloud {
+
+SavesSyncRequest::SavesSyncRequest(Storage *storage, Storage::BoolCallback callback):
+	Request(nullptr), _storage(storage), _boolCallback(callback),
+	_workingRequest(nullptr), _ignoreCallback(false) {
+	start();
+}
+
+SavesSyncRequest::~SavesSyncRequest() {
+	_ignoreCallback = true;
+	if (_workingRequest) _workingRequest->finish();
+	delete _boolCallback;
+}
+
+void SavesSyncRequest::start() {
+	//cleanup
+	_ignoreCallback = true;
+	if (_workingRequest) _workingRequest->finish();	
+	_currentDownloadingFile = StorageFile();
+	_currentUploadingFile = "";
+	_filesToDownload.clear();
+	_filesToUpload.clear();
+	_localFilesTimestamps.clear();
+	_ignoreCallback = false;
+
+	//load timestamps
+	loadTimestamps();
+
+	//list saves directory
+	_workingRequest = _storage->listDirectory("saves", new Common::Callback<SavesSyncRequest, Storage::FileArrayResponse>(this, &SavesSyncRequest::directoryListedCallback));
+}
+
+void SavesSyncRequest::directoryListedCallback(Storage::FileArrayResponse pair) {
+	if (_ignoreCallback) return;
+	//TODO: somehow ListDirectory requests must indicate that file array is incomplete
+
+	const uint32 INVALID_TIMESTAMP = UINT_MAX;
+	
+	//determine which files to download and which files to upload
+	Common::Array<StorageFile> &remoteFiles = pair.value;
+	for (uint32 i = 0; i < remoteFiles.size(); ++i) {
+		StorageFile &file = remoteFiles[i];
+		if (file.isDirectory()) continue;
+		Common::String name = file.name();
+		if (!_localFilesTimestamps.contains(name))
+			_filesToDownload.push_back(file);
+		else {
+			if (_localFilesTimestamps[name] != INVALID_TIMESTAMP) {
+				if (_localFilesTimestamps[name] == file.timestamp())
+					continue;
+
+				//we actually can have some files not only with timestamp < remote
+				//but also with timestamp > remote (when we have been using ANOTHER CLOUD and then switched back)
+				if (_localFilesTimestamps[name] < file.timestamp())
+					_filesToDownload.push_back(file);
+				else
+					_filesToUpload.push_back(file.name());
+			}
+		}
+	}
+
+	//upload files with invalid timestamp (the ones we've added - means they might not have any remote version)
+	for (Common::HashMap<Common::String, uint32>::iterator i = _localFilesTimestamps.begin(); i != _localFilesTimestamps.end(); ++i) {
+		if (i->_value == INVALID_TIMESTAMP)
+			_filesToUpload.push_back(i->_key);
+	}
+
+	//start downloading files
+	downloadNextFile();
+}
+
+void SavesSyncRequest::downloadNextFile() {
+	if (_filesToDownload.empty()) {
+		uploadNextFile();
+		return;
+	}
+
+	_currentDownloadingFile = _filesToDownload.back();
+	_filesToDownload.pop_back();
+
+	_workingRequest = _storage->download(_currentDownloadingFile.path(), "saves/" + _currentDownloadingFile.name(),
+		new Common::Callback<SavesSyncRequest, Storage::BoolResponse>(this, &SavesSyncRequest::fileDownloadedCallback)
+	);
+}
+
+void SavesSyncRequest::fileDownloadedCallback(Storage::BoolResponse pair) {
+	if (_ignoreCallback) return;
+
+	//stop syncing if download failed
+	if (!pair.value) {
+		finish();
+		return;
+	}
+
+	//update local timestamp for downloaded file
+	_localFilesTimestamps[_currentDownloadingFile.name()] = _currentDownloadingFile.timestamp();
+
+	//continue downloading files
+	downloadNextFile();
+}
+
+void SavesSyncRequest::uploadNextFile() {
+	if (_filesToUpload.empty()) {
+		finishBool(true);
+		return;
+	}
+
+	_currentUploadingFile = _filesToUpload.back();
+	_filesToUpload.pop_back();
+
+	_workingRequest = _storage->upload("saves/" + _currentUploadingFile, nullptr, //TODO: pass save's read stream
+		new Common::Callback<SavesSyncRequest, Storage::BoolResponse>(this, &SavesSyncRequest::fileUploadedCallback)
+	);
+}
+
+void SavesSyncRequest::fileUploadedCallback(Storage::BoolResponse pair) {
+	if (_ignoreCallback) return;
+
+	//stop syncing if upload failed
+	if (!pair.value) {
+		finish();
+		return;
+	}
+
+	//TODO: update local timestamp for the uploaded file
+	//_localFilesTimestamps[_currentUploadingFile] = pair.request.<what?>;
+
+	//continue uploading files
+	uploadNextFile();
+}
+
+void SavesSyncRequest::handle() {}
+
+void SavesSyncRequest::restart() { start(); }
+
+void SavesSyncRequest::finish() { finishBool(false); }
+
+void SavesSyncRequest::finishBool(bool success) {
+	Request::finish();
+
+	//save updated timestamps (even if Request failed, there would be only valid timestamps)
+	saveTimestamps();
+
+	if (_boolCallback) (*_boolCallback)(Storage::BoolResponse(this, success));
+}
+
+void SavesSyncRequest::loadTimestamps() {
+	Common::File f;
+	if (!f.open("saves/timestamps"))
+		error("SavesSyncRequest: failed to open 'saves/timestamps' file to load timestamps");
+	
+	while (!f.eos()) {
+		//read filename into buffer (reading until the first ' ')
+		Common::String buffer;
+		while (!f.eos()) {
+			byte b = f.readByte();
+			if (b == ' ') break;
+			buffer += (char)b;
+		}
+		
+		//read timestamp info buffer (reading until ' ' or some line ending char)
+		Common::String filename = buffer;
+		bool lineEnded = false;
+		buffer = "";
+		while (!f.eos()) {
+			byte b = f.readByte();
+			if (b == ' ' || b == '\n' || b == '\r') {
+				lineEnded = (b == '\n');
+				break;
+			}
+			buffer += (char)b;
+		}
+
+		//parse timestamp
+		uint timestamp = atol(buffer.c_str());
+		_localFilesTimestamps[filename] = timestamp;
+
+		//read until the end of the line
+		if (!lineEnded) {
+			while (!f.eos()) {
+				byte b = f.readByte();
+				if (b == '\n') break;
+			}
+		}
+	}
+
+	f.close();
+}
+
+void SavesSyncRequest::saveTimestamps() {
+	Common::DumpFile f;
+	if (!f.open("saves/timestamps", true))
+		error("SavesSyncRequest: failed to open 'saves/timestamps' file to save timestamps");
+	Common::String data;
+	for (Common::HashMap<Common::String, uint32>::iterator i = _localFilesTimestamps.begin(); i != _localFilesTimestamps.end(); ++i)
+		data += i->_key + Common::String::format(" %u\n", i->_value);
+	if (f.write(data.c_str(), data.size()) != data.size())
+		error("SavesSyncRequest: failed to write timestamps data into 'saves/timestamps'");
+	f.close();
+}
+
+
+} // End of namespace Cloud