gecko-dev/dom/media/webaudio/AudioParam.cpp

/* -*- 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/. */

#include "AudioParam.h"
#include "mozilla/dom/AudioParamBinding.h"
#include "AudioNodeEngine.h"
#include "AudioNodeStream.h"
#include "AudioContext.h"

namespace mozilla {
namespace dom {

NS_IMPL_CYCLE_COLLECTION_CLASS(AudioParam)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AudioParam)
  tmp->DisconnectFromGraphAndDestroyStream();
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mNode)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(AudioParam)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mNode)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_WRAPPERCACHE(AudioParam)

NS_IMPL_CYCLE_COLLECTING_NATIVE_ADDREF(AudioParam)
NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE(AudioParam)

NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(AudioParam, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(AudioParam, Release)

AudioParam::AudioParam(AudioNode* aNode, uint32_t aIndex, const char* aName,
                       float aDefaultValue, float aMinValue, float aMaxValue)
    : AudioParamTimeline(aDefaultValue),
      mNode(aNode),
      mName(aName),
      mIndex(aIndex),
      mDefaultValue(aDefaultValue),
      mMinValue(aMinValue),
      mMaxValue(aMaxValue) {}

AudioParam::~AudioParam() { DisconnectFromGraphAndDestroyStream(); }

JSObject* AudioParam::WrapObject(JSContext* aCx,
                                 JS::Handle<JSObject*> aGivenProto) {
  return AudioParam_Binding::Wrap(aCx, this, aGivenProto);
}

void AudioParam::DisconnectFromGraphAndDestroyStream() {
  MOZ_ASSERT(mRefCnt.get() > mInputNodes.Length(),
             "Caller should be holding a reference or have called "
             "mRefCnt.stabilizeForDeletion()");

  while (!mInputNodes.IsEmpty()) {
    uint32_t i = mInputNodes.Length() - 1;
    RefPtr<AudioNode> input = mInputNodes[i].mInputNode;
    mInputNodes.RemoveElementAt(i);
    input->RemoveOutputParam(this);
  }

  if (mNodeStreamPort) {
    mNodeStreamPort->Destroy();
    mNodeStreamPort = nullptr;
  }

  if (mStream) {
    mStream->Destroy();
    mStream = nullptr;
  }
}

MediaStream* AudioParam::GetStream() const { return mStream; }

MediaStream* AudioParam::Stream() {
  if (mStream) {
    return mStream;
  }

  AudioNodeEngine* engine = new AudioNodeEngine(nullptr);
  mStream = AudioNodeStream::Create(mNode->Context(), engine,
                                    AudioNodeStream::NO_STREAM_FLAGS,
                                    mNode->Context()->Graph());

  // Force the input to have only one channel, and make it down-mix using
  // the speaker rules if needed.
  mStream->SetChannelMixingParametersImpl(1, ChannelCountMode::Explicit,
                                          ChannelInterpretation::Speakers);
  // Mark as an AudioParam helper stream
  mStream->SetAudioParamHelperStream();

  // Setup the AudioParam's stream as an input to the owner AudioNode's stream
  AudioNodeStream* nodeStream = mNode->GetStream();
  if (nodeStream) {
    mNodeStreamPort =
        nodeStream->AllocateInputPort(mStream, AudioNodeStream::AUDIO_TRACK);
  }

  // Send the stream to the timeline on the MSG side.
  AudioTimelineEvent event(mStream);
  SendEventToEngine(event);

  return mStream;
}

static const char* ToString(AudioTimelineEvent::Type aType) {
  switch (aType) {
    case AudioTimelineEvent::SetValue:
      return "SetValue";
    case AudioTimelineEvent::SetValueAtTime:
      return "SetValueAtTime";
    case AudioTimelineEvent::LinearRamp:
      return "LinearRamp";
    case AudioTimelineEvent::ExponentialRamp:
      return "ExponentialRamp";
    case AudioTimelineEvent::SetTarget:
      return "SetTarget";
    case AudioTimelineEvent::SetValueCurve:
      return "SetValueCurve";
    case AudioTimelineEvent::Stream:
      return "Stream";
    case AudioTimelineEvent::Cancel:
      return "Cancel";
    default:
      return "unknown AudioTimelineEvent";
  }
}

void AudioParam::SendEventToEngine(const AudioTimelineEvent& aEvent) {
  WEB_AUDIO_API_LOG(
      "%f: %s for %u %s %s=%g time=%f %s=%g", GetParentObject()->CurrentTime(),
      mName, ParentNodeId(), ToString(aEvent.mType),
      aEvent.mType == AudioTimelineEvent::SetValueCurve ? "length" : "value",
      aEvent.mType == AudioTimelineEvent::SetValueCurve
          ? static_cast<double>(aEvent.mCurveLength)
          : static_cast<double>(aEvent.mValue),
      aEvent.Time<double>(),
      aEvent.mType == AudioTimelineEvent::SetValueCurve ? "duration"
                                                        : "constant",
      aEvent.mType == AudioTimelineEvent::SetValueCurve ? aEvent.mDuration
                                                        : aEvent.mTimeConstant);

  AudioNodeStream* stream = mNode->GetStream();
  if (stream) {
    stream->SendTimelineEvent(mIndex, aEvent);
  }
}

void AudioParam::CleanupOldEvents() {
  MOZ_ASSERT(NS_IsMainThread());
  double currentTime = mNode->Context()->CurrentTime();

  CleanupEventsOlderThan(currentTime);
}

float AudioParamTimeline::AudioNodeInputValue(size_t aCounter) const {
  MOZ_ASSERT(mStream);

  // If we have a chunk produced by the AudioNode inputs to the AudioParam,
  // get its value now.  We use aCounter to tell us which frame of the last
  // AudioChunk to look at.
  float audioNodeInputValue = 0.0f;
  const AudioBlock& lastAudioNodeChunk = mStream->LastChunks()[0];
  if (!lastAudioNodeChunk.IsNull()) {
    MOZ_ASSERT(lastAudioNodeChunk.GetDuration() == WEBAUDIO_BLOCK_SIZE);
    audioNodeInputValue =
        static_cast<const float*>(lastAudioNodeChunk.mChannelData[0])[aCounter];
    audioNodeInputValue *= lastAudioNodeChunk.mVolume;
  }

  return audioNodeInputValue;
}

}  // namespace dom
}  // namespace mozilla