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// Copyright (c) 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_ASYNC_DESTROY_VIDEO_DECODER_H_
#define MEDIA_BASE_ASYNC_DESTROY_VIDEO_DECODER_H_
#include <memory>
#include <type_traits>
#include "media/base/video_decoder.h"
namespace media {
// Some VideoDecoder implementations must do non-synchronous cleanup before
// they are destroyed. This wrapper implementation allows a VideoDecoder
// to schedule its own cleanup tasks before its memory is released.
// The underlying type must implement a static
// `DestroyAsync(std::unique_ptr<T>)` function which fires any pending
// callbacks, stops and destroys the decoder. After this call, external
// resources (e.g. raw pointers) held by the decoder might be invalidated
// immediately. So if the decoder is destroyed asynchronously (e.g. DeleteSoon),
// external resources must be released in this call.
template <typename T>
class AsyncDestroyVideoDecoder final : public VideoDecoder {
public:
explicit AsyncDestroyVideoDecoder(std::unique_ptr<T> wrapped_decoder)
: wrapped_decoder_(std::move(wrapped_decoder)) {
static_assert(std::is_base_of<VideoDecoder, T>::value,
"T must implement 'media::VideoDecoder'");
DCHECK(wrapped_decoder_);
}
~AsyncDestroyVideoDecoder() override {
if (wrapped_decoder_)
T::DestroyAsync(std::move(wrapped_decoder_));
}
VideoDecoderType GetDecoderType() const override {
DCHECK(wrapped_decoder_);
return wrapped_decoder_->GetDecoderType();
}
std::string GetDisplayName() const override {
DCHECK(wrapped_decoder_);
return wrapped_decoder_->GetDisplayName();
}
bool IsPlatformDecoder() const override {
DCHECK(wrapped_decoder_);
return wrapped_decoder_->IsPlatformDecoder();
}
void Initialize(const VideoDecoderConfig& config,
bool low_delay,
CdmContext* cdm_context,
InitCB init_cb,
const OutputCB& output_cb,
const WaitingCB& waiting_cb) override {
DCHECK(wrapped_decoder_);
wrapped_decoder_->Initialize(config, low_delay, cdm_context,
std::move(init_cb), output_cb, waiting_cb);
}
void Decode(scoped_refptr<DecoderBuffer> buffer,
DecodeCB decode_cb) override {
DCHECK(wrapped_decoder_);
wrapped_decoder_->Decode(std::move(buffer), std::move(decode_cb));
}
void Reset(base::OnceClosure closure) override {
DCHECK(wrapped_decoder_);
wrapped_decoder_->Reset(std::move(closure));
}
bool NeedsBitstreamConversion() const override {
DCHECK(wrapped_decoder_);
return wrapped_decoder_->NeedsBitstreamConversion();
}
bool CanReadWithoutStalling() const override {
DCHECK(wrapped_decoder_);
return wrapped_decoder_->CanReadWithoutStalling();
}
int GetMaxDecodeRequests() const override {
DCHECK(wrapped_decoder_);
return wrapped_decoder_->GetMaxDecodeRequests();
}
private:
std::unique_ptr<T> wrapped_decoder_;
};
} // namespace media
#endif // MEDIA_BASE_ASYNC_DESTROY_VIDEO_DECODER_H_
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