third_party/WebKit/Source/modules/webaudio/AudioNodeOutput.cpp

/*
 * Copyright (C) 2010, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1.  Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
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 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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#include "modules/webaudio/AudioNodeInput.h"
#include "modules/webaudio/AudioNodeOutput.h"
#include "modules/webaudio/BaseAudioContext.h"
#include "wtf/PtrUtil.h"
#include "wtf/Threading.h"
#include <memory>

namespace blink {

inline AudioNodeOutput::AudioNodeOutput(AudioHandler* handler,
                                        unsigned numberOfChannels)
    : m_handler(*handler),
      m_numberOfChannels(numberOfChannels),
      m_desiredNumberOfChannels(numberOfChannels),
      m_isInPlace(false),
      m_isEnabled(true),
      m_didCallDispose(false),
      m_renderingFanOutCount(0),
      m_renderingParamFanOutCount(0) {
  DCHECK_LE(numberOfChannels, BaseAudioContext::maxNumberOfChannels());

  m_internalBus =
      AudioBus::create(numberOfChannels, AudioHandler::ProcessingSizeInFrames);
}

std::unique_ptr<AudioNodeOutput> AudioNodeOutput::create(
    AudioHandler* handler,
    unsigned numberOfChannels) {
  return wrapUnique(new AudioNodeOutput(handler, numberOfChannels));
}

void AudioNodeOutput::dispose() {
  m_didCallDispose = true;

  deferredTaskHandler().removeMarkedAudioNodeOutput(this);
  disconnectAll();
  DCHECK(m_inputs.isEmpty());
  DCHECK(m_params.isEmpty());
}

void AudioNodeOutput::setNumberOfChannels(unsigned numberOfChannels) {
  DCHECK_LE(numberOfChannels, BaseAudioContext::maxNumberOfChannels());
  ASSERT(deferredTaskHandler().isGraphOwner());

  m_desiredNumberOfChannels = numberOfChannels;

  if (deferredTaskHandler().isAudioThread()) {
    // If we're in the audio thread then we can take care of it right away (we should be at the very start or end of a rendering quantum).
    updateNumberOfChannels();
  } else {
    DCHECK(!m_didCallDispose);
    // Let the context take care of it in the audio thread in the pre and post render tasks.
    deferredTaskHandler().markAudioNodeOutputDirty(this);
  }
}

void AudioNodeOutput::updateInternalBus() {
  if (numberOfChannels() == m_internalBus->numberOfChannels())
    return;

  m_internalBus = AudioBus::create(numberOfChannels(),
                                   AudioHandler::ProcessingSizeInFrames);
}

void AudioNodeOutput::updateRenderingState() {
  updateNumberOfChannels();
  m_renderingFanOutCount = fanOutCount();
  m_renderingParamFanOutCount = paramFanOutCount();
}

void AudioNodeOutput::updateNumberOfChannels() {
  DCHECK(deferredTaskHandler().isAudioThread());
  ASSERT(deferredTaskHandler().isGraphOwner());

  if (m_numberOfChannels != m_desiredNumberOfChannels) {
    m_numberOfChannels = m_desiredNumberOfChannels;
    updateInternalBus();
    propagateChannelCount();
  }
}

void AudioNodeOutput::propagateChannelCount() {
  DCHECK(deferredTaskHandler().isAudioThread());
  ASSERT(deferredTaskHandler().isGraphOwner());

  if (isChannelCountKnown()) {
    // Announce to any nodes we're connected to that we changed our channel count for its input.
    for (AudioNodeInput* i : m_inputs)
      i->handler().checkNumberOfChannelsForInput(i);
  }
}

AudioBus* AudioNodeOutput::pull(AudioBus* inPlaceBus, size_t framesToProcess) {
  DCHECK(deferredTaskHandler().isAudioThread());
  DCHECK(m_renderingFanOutCount > 0 || m_renderingParamFanOutCount > 0);

  // Causes our AudioNode to process if it hasn't already for this render quantum.
  // We try to do in-place processing (using inPlaceBus) if at all possible,
  // but we can't process in-place if we're connected to more than one input (fan-out > 1).
  // In this case pull() is called multiple times per rendering quantum, and the processIfNecessary() call below will
  // cause our node to process() only the first time, caching the output in m_internalOutputBus for subsequent calls.

  m_isInPlace = inPlaceBus &&
                inPlaceBus->numberOfChannels() == numberOfChannels() &&
                (m_renderingFanOutCount + m_renderingParamFanOutCount) == 1;

  m_inPlaceBus = m_isInPlace ? inPlaceBus : 0;

  handler().processIfNecessary(framesToProcess);
  return bus();
}

AudioBus* AudioNodeOutput::bus() const {
  DCHECK(deferredTaskHandler().isAudioThread());
  return m_isInPlace ? m_inPlaceBus.get() : m_internalBus.get();
}

unsigned AudioNodeOutput::fanOutCount() {
  ASSERT(deferredTaskHandler().isGraphOwner());
  return m_inputs.size();
}

unsigned AudioNodeOutput::paramFanOutCount() {
  ASSERT(deferredTaskHandler().isGraphOwner());
  return m_params.size();
}

unsigned AudioNodeOutput::renderingFanOutCount() const {
  return m_renderingFanOutCount;
}

void AudioNodeOutput::addInput(AudioNodeInput& input) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  m_inputs.add(&input);
  input.handler().makeConnection();
}

void AudioNodeOutput::removeInput(AudioNodeInput& input) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  input.handler().breakConnection();
  m_inputs.remove(&input);
}

void AudioNodeOutput::disconnectAllInputs() {
  ASSERT(deferredTaskHandler().isGraphOwner());

  // AudioNodeInput::disconnect() changes m_inputs by calling removeInput().
  while (!m_inputs.isEmpty())
    (*m_inputs.begin())->disconnect(*this);
}

void AudioNodeOutput::disconnectInput(AudioNodeInput& input) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  DCHECK(isConnectedToInput(input));
  input.disconnect(*this);
}

void AudioNodeOutput::disconnectAudioParam(AudioParamHandler& param) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  DCHECK(isConnectedToAudioParam(param));
  param.disconnect(*this);
}

void AudioNodeOutput::addParam(AudioParamHandler& param) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  m_params.add(&param);
}

void AudioNodeOutput::removeParam(AudioParamHandler& param) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  m_params.remove(&param);
}

void AudioNodeOutput::disconnectAllParams() {
  ASSERT(deferredTaskHandler().isGraphOwner());

  // AudioParam::disconnect() changes m_params by calling removeParam().
  while (!m_params.isEmpty())
    (*m_params.begin())->disconnect(*this);
}

void AudioNodeOutput::disconnectAll() {
  disconnectAllInputs();
  disconnectAllParams();
}

bool AudioNodeOutput::isConnectedToInput(AudioNodeInput& input) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  return m_inputs.contains(&input);
}

bool AudioNodeOutput::isConnectedToAudioParam(AudioParamHandler& param) {
  ASSERT(deferredTaskHandler().isGraphOwner());
  return m_params.contains(&param);
}

void AudioNodeOutput::disable() {
  ASSERT(deferredTaskHandler().isGraphOwner());

  if (m_isEnabled) {
    m_isEnabled = false;
    for (AudioNodeInput* i : m_inputs)
      i->disable(*this);
  }
}

void AudioNodeOutput::enable() {
  ASSERT(deferredTaskHandler().isGraphOwner());

  if (!m_isEnabled) {
    m_isEnabled = true;
    for (AudioNodeInput* i : m_inputs)
      i->enable(*this);
  }
}

}  // namespace blink