EncoderAgent.h - mozsearch

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef DOM_MEDIA_WEBCODECS_EncoderAgent_H

#define DOM_MEDIA_WEBCODECS_EncoderAgent_H

#include "MediaResult.h"

#include "PlatformEncoderModule.h"

#include "PEMFactory.h"

#include "mozilla/RefPtr.h"

#include "mozilla/TaskQueue.h"

#include "WebCodecsUtils.h"

class nsISerialEventTarget;

namespace mozilla {

class PDMFactory;

class TrackInfo;

namespace layers {

class ImageContainer;

}  // namespace layers

// EncoderAgent is a wrapper that contains a MediaDataEncoder. It adapts the

// MediaDataEncoder APIs for use in WebCodecs.

//

// If Configure() is called, Shutdown() must be called to release the resources

// gracefully. Except Shutdown(), all the methods can't be called concurrently,

// meaning a method can only be called when the previous API call has completed.

// The responsability of arranging the method calls is on the caller.

//

// When Shutdown() is called, all the operations in flight are canceled and the

// MediaDataEncoder is shut down. On the other hand, errors are final. A new

// EncoderAgent must be created when an error is encountered.

//

// All the methods need to be called on the EncoderAgent's owner thread. In

// WebCodecs, it's either on the main thread or worker thread.

class EncoderAgent final {

 public:

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(EncoderAgent);

  explicit EncoderAgent(WebCodecsId aId);

  // The following APIs are owner thread only.

  using ConfigurePromise = MozPromise<bool, MediaResult, true /* exclusive */>;

  using ReconfigurationPromise = MediaDataEncoder::ReconfigurationPromise;

  RefPtr<ConfigurePromise> Configure(const EncoderConfig& aConfig);

  RefPtr<ReconfigurationPromise> Reconfigure(

      const RefPtr<const EncoderConfigurationChangeList>& aConfigChange);

  RefPtr<ShutdownPromise> Shutdown();

  using EncodePromise = MediaDataEncoder::EncodePromise;

  RefPtr<EncodePromise> Encode(MediaData* aInput);

  // WebCodecs's flush() flushes out all the pending encoded data in the

  // encoder. It's called Drain internally.

  RefPtr<EncodePromise> Drain();

  const WebCodecsId mId;

 private:

  ~EncoderAgent();

  // Push out all the data in the MediaDataEncoder's pipeline.

  // TODO: MediaDataEncoder should implement this, instead of asking call site

  // to run `Drain` multiple times.

  RefPtr<EncodePromise> Dry();

  void DryUntilDrain();

  enum class State {

    Unconfigured,

    Configuring,

    Configured,

    Encoding,

    Flushing,

    ShuttingDown,

    Error,

};

  void SetState(State aState);

  const RefPtr<nsISerialEventTarget> mOwnerThread;

  const RefPtr<PEMFactory> mPEMFactory;

  RefPtr<MediaDataEncoder> mEncoder;

  State mState;

  // Configure

  MozPromiseHolder<ConfigurePromise> mConfigurePromise;

  using CreateEncoderPromise = PlatformEncoderModule::CreateEncoderPromise;

  MozPromiseRequestHolder<CreateEncoderPromise> mCreateRequest;

  using InitPromise = MediaDataEncoder::InitPromise;

  MozPromiseRequestHolder<InitPromise> mInitRequest;

  // Reconfigure

  MozPromiseHolder<ReconfigurationPromise> mReconfigurationPromise;

  using ReconfigureEncoderRequest = ReconfigurationPromise;

  MozPromiseRequestHolder<ReconfigureEncoderRequest> mReconfigurationRequest;

  // Shutdown

  MozPromiseHolder<ShutdownPromise> mShutdownWhileCreationPromise;

  // Encoding

  MozPromiseHolder<EncodePromise> mEncodePromise;

  MozPromiseRequestHolder<EncodePromise> mEncodeRequest;

  // Drain

  MozPromiseRequestHolder<EncodePromise> mDrainRequest;

  MozPromiseHolder<EncodePromise> mDrainPromise;

  MediaDataEncoder::EncodedData mDrainData;

};

}  // namespace mozilla

#endif  // DOM_MEDIA_WEBCODECS_EncoderAgent_H