Source/WebCore/Modules/webaudio/DefaultAudioDestinationNode.cpp

/*
 * Copyright (C) 2011, Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in the
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 *
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "DefaultAudioDestinationNode.h"

#include "AudioContext.h"
#include "AudioDestination.h"
#include "Logging.h"
#include "ScriptExecutionContext.h"
#include <wtf/MainThread.h>

const unsigned EnabledInputChannels = 2;

namespace WebCore {
    
DefaultAudioDestinationNode::DefaultAudioDestinationNode(AudioContext& context)
    : AudioDestinationNode(context, AudioDestination::hardwareSampleRate())
{
    // Node-specific default mixing rules.
    m_channelCount = 2;
    m_channelCountMode = Explicit;
    m_channelInterpretation = AudioBus::Speakers;
}

DefaultAudioDestinationNode::~DefaultAudioDestinationNode()
{
    uninitialize();
}

void DefaultAudioDestinationNode::initialize()
{
    ASSERT(isMainThread()); 
    if (isInitialized())
        return;

    createDestination();
    AudioNode::initialize();
}

void DefaultAudioDestinationNode::uninitialize()
{
    ASSERT(isMainThread()); 
    if (!isInitialized())
        return;

    m_destination->stop();
    m_numberOfInputChannels = 0;

    AudioNode::uninitialize();
}

void DefaultAudioDestinationNode::createDestination()
{
    float hardwareSampleRate = AudioDestination::hardwareSampleRate();
    LOG(WebAudio, ">>>> hardwareSampleRate = %f\n", hardwareSampleRate);
    
    m_destination = AudioDestination::create(*this, m_inputDeviceId, m_numberOfInputChannels, channelCount(), hardwareSampleRate);
}

void DefaultAudioDestinationNode::enableInput(const String& inputDeviceId)
{
    ASSERT(isMainThread());
    if (m_numberOfInputChannels != EnabledInputChannels) {
        m_numberOfInputChannels = EnabledInputChannels;
        m_inputDeviceId = inputDeviceId;

        if (isInitialized()) {
            // Re-create destination.
            m_destination->stop();
            createDestination();
            m_destination->start();
        }
    }
}

void DefaultAudioDestinationNode::startRendering()
{
    ASSERT(isInitialized());
    if (isInitialized())
        m_destination->start();
}

void DefaultAudioDestinationNode::resume(Function<void ()>&& function)
{
    ASSERT(isInitialized());
    if (isInitialized())
        m_destination->start();
    if (auto scriptExecutionContext = context().scriptExecutionContext())
        scriptExecutionContext->postTask(WTFMove(function));
}

void DefaultAudioDestinationNode::suspend(Function<void ()>&& function)
{
    ASSERT(isInitialized());
    if (isInitialized())
        m_destination->stop();
    if (auto scriptExecutionContext = context().scriptExecutionContext())
        scriptExecutionContext->postTask(WTFMove(function));
}

void DefaultAudioDestinationNode::close(Function<void()>&& function)
{
    ASSERT(isInitialized());
    uninitialize();
    if (auto scriptExecutionContext = context().scriptExecutionContext())
        scriptExecutionContext->postTask(WTFMove(function));
}

unsigned DefaultAudioDestinationNode::maxChannelCount() const
{
    return AudioDestination::maxChannelCount();
}

ExceptionOr<void> DefaultAudioDestinationNode::setChannelCount(unsigned channelCount)
{
    // The channelCount for the input to this node controls the actual number of channels we
    // send to the audio hardware. It can only be set depending on the maximum number of
    // channels supported by the hardware.

    ASSERT(isMainThread());

    if (!maxChannelCount() || channelCount > maxChannelCount())
        return Exception { InvalidStateError };

    auto oldChannelCount = this->channelCount();
    auto result = AudioNode::setChannelCount(channelCount);
    if (result.hasException())
        return result;

    if (this->channelCount() != oldChannelCount && isInitialized()) {
        // Re-create destination.
        m_destination->stop();
        createDestination();
        m_destination->start();
    }

    return { };
}

bool DefaultAudioDestinationNode::isPlaying()
{
    return m_destination && m_destination->isPlaying();
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)