AudioDestinationNode.h

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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 AudioDestinationNode_h_

#define AudioDestinationNode_h_

#include "AudioChannelService.h"

#include "AudioNode.h"

#include "AudioChannelAgent.h"

#include "mozilla/TimeStamp.h"

namespace mozilla::dom {

class AudioContext;

class WakeLock;

class AudioDestinationNode final : public AudioNode,

                                   public nsIAudioChannelAgentCallback,

                                   public MainThreadMediaTrackListener {

 public:

  // This node type knows what MediaTrackGraph to use based on

  // whether it's in offline mode.

  AudioDestinationNode(AudioContext* aContext, bool aIsOffline,

                       uint32_t aNumberOfChannels, uint32_t aLength);

  void DestroyMediaTrack() override;

  NS_DECL_ISUPPORTS_INHERITED

  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(AudioDestinationNode, AudioNode)

  NS_DECL_NSIAUDIOCHANNELAGENTCALLBACK

  JSObject* WrapObject(JSContext* aCx,

                       JS::Handle<JSObject*> aGivenProto) override;

  uint16_t NumberOfOutputs() const final { return 0; }

  uint32_t MaxChannelCount() const;

  void SetChannelCount(uint32_t aChannelCount, ErrorResult& aRv) override;

  void Init();

  void Close();

  // Returns the track or null after unlink.

  AudioNodeTrack* Track();

  void Mute();

  void Unmute();

  void Suspend();

  void Resume();

  void StartRendering(Promise* aPromise);

  void OfflineShutdown();

  void NotifyMainThreadTrackEnded() override;

  void FireOfflineCompletionEvent();

  const char* NodeType() const override { return "AudioDestinationNode"; }

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override;

  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override;

  void NotifyDataAudibleStateChanged(bool aAudible);

  void ResolvePromise(AudioBuffer* aRenderedBuffer);

  unsigned long Length() {

    MOZ_ASSERT(mIsOffline);

    return mFramesToProduce;

  void NotifyAudioContextStateChanged();

 protected:

  virtual ~AudioDestinationNode();

 private:

  // This would be created for non-offline audio context in order to receive

  // tab's mute/suspend/audio capture state change and update the audible state

  // to the tab.

  void CreateAndStartAudioChannelAgent();

  void DestroyAudioChannelAgentIfExists();

  RefPtr<AudioChannelAgent> mAudioChannelAgent;

  // These members are related to audio capturing. We would start capturing

  // audio if we're starting capturing audio from whole window, and MUST stop

  // capturing explicitly when we don't need to capture audio any more, because

  // we have to release the resource we allocated before.

  bool IsCapturingAudio() const;

  void StartAudioCapturingTrack();

  void StopAudioCapturingTrack();

  RefPtr<MediaInputPort> mCaptureTrackPort;

  // These members are used to determine if the destination node is actual

  // audible and `mFinalAudibleState` represents the final result.

  using AudibleChangedReasons = AudioChannelService::AudibleChangedReasons;

  using AudibleState = AudioChannelService::AudibleState;

  void UpdateFinalAudibleStateIfNeeded(AudibleChangedReasons aReason);

  bool IsAudible() const;

  bool mFinalAudibleState = false;

  bool mIsDataAudible = false;

  float mAudioChannelVolume = 1.0;

  // True if the audio channel disables the track for unvisited tab, and the

  // track will be enabled again when the tab gets first visited, or a user

  // presses the tab play icon.

  bool mAudioChannelDisabled = false;

  // When the destination node is audible, we would request a wakelock to

  // prevent computer from sleeping in order to keep audio playing.

  void CreateAudioWakeLockIfNeeded();

  void ReleaseAudioWakeLockIfExists();

  RefPtr<WakeLock> mWakeLock;

  SelfReference<AudioDestinationNode> mOfflineRenderingRef;

  uint32_t mFramesToProduce;

  RefPtr<Promise> mOfflineRenderingPromise;

  bool mIsOffline;

  // These varaibles are used to know how long AudioContext would become audible

  // since it was created.

  TimeStamp mCreatedTime;

  TimeDuration mDurationBeforeFirstTimeAudible;

};

}  // namespace mozilla::dom

#endif