tdesktop/Telegram/SourceFiles/storage/streamed_file_downloader.cpp

166 lines
3.5 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.
For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
*/
#include "storage/streamed_file_downloader.h"
#include "media/streaming/media_streaming_loader.h"
#include "media/streaming/media_streaming_reader.h"
namespace Storage {
namespace {
using namespace Media::Streaming;
constexpr auto kPartSize = Loader::kPartSize;
constexpr auto kRequestPartsCount = 8;
} // namespace
StreamedFileDownloader::StreamedFileDownloader(
uint64 objectId,
MTP::DcId dcId,
Data::FileOrigin origin,
Cache::Key cacheKey,
MediaKey fileLocationKey,
std::shared_ptr<Reader> reader,
// For FileLoader
const QString &toFile,
int32 size,
LocationType locationType,
LoadToCacheSetting toCache,
LoadFromCloudSetting fromCloud,
bool autoLoading,
uint8 cacheTag)
: FileLoader(
toFile,
size,
locationType,
toCache,
fromCloud,
autoLoading,
cacheTag)
, _objectId(objectId)
, _origin(origin)
, _cacheKey(cacheKey)
, _fileLocationKey(fileLocationKey)
, _reader(std::move(reader))
, _partsCount((size + kPartSize - 1) / kPartSize) {
_partIsSaved.resize(_partsCount, false);
_reader->partsForDownloader(
) | rpl::start_with_next([=](const LoadedPart &part) {
if (part.offset == LoadedPart::kFailedOffset) {
cancel(true);
} else {
savePart(std::move(part));
}
}, _lifetime);
}
StreamedFileDownloader::~StreamedFileDownloader() {
if (!_finished) {
cancel();
}
}
uint64 StreamedFileDownloader::objId() const {
return _objectId;
}
Data::FileOrigin StreamedFileDownloader::fileOrigin() const {
return _origin;
}
void StreamedFileDownloader::requestParts() {
while (!_finished
&& _nextPartIndex < _partsCount
&& _partsRequested < kRequestPartsCount) {
requestPart();
}
}
void StreamedFileDownloader::requestPart() {
Expects(!_finished);
const auto index = std::find(
begin(_partIsSaved) + _nextPartIndex,
end(_partIsSaved),
false
) - begin(_partIsSaved);
if (index == _partsCount) {
_nextPartIndex = _partsCount;
return;
}
_nextPartIndex = index + 1;
_reader->loadForDownloader(this, index * kPartSize);
++_partsRequested;
}
QByteArray StreamedFileDownloader::readLoadedPart(int offset) {
Expects(offset >= 0 && offset < _size);
Expects(!(offset % kPartSize));
const auto index = (offset / kPartSize);
return _partIsSaved[index]
? readLoadedPartBack(offset, kPartSize)
: QByteArray();
}
Storage::Cache::Key StreamedFileDownloader::cacheKey() const {
return _cacheKey;
}
std::optional<MediaKey> StreamedFileDownloader::fileLocationKey() const {
return _fileLocationKey;
}
void StreamedFileDownloader::cancelHook() {
_partsRequested = 0;
_nextPartIndex = 0;
_reader->cancelForDownloader(this);
}
void StreamedFileDownloader::startLoading() {
requestParts();
}
void StreamedFileDownloader::savePart(const LoadedPart &part) {
Expects(part.offset >= 0 && part.offset < _reader->size());
Expects(part.offset % kPartSize == 0);
if (_finished || _cancelled) {
return;
}
const auto offset = part.offset;
const auto index = offset / kPartSize;
Assert(index >= 0 && index < _partsCount);
if (_partIsSaved[index]) {
return;
}
_partIsSaved[index] = true;
++_partsSaved;
if (index < _nextPartIndex) {
--_partsRequested;
}
if (!writeResultPart(offset, bytes::make_span(part.bytes))) {
return;
}
_reader->doneForDownloader(offset);
if (_partsSaved == _partsCount) {
finalizeResult();
} else {
requestParts();
notifyAboutProgress();
}
}
} // namespace Storage