root/Source/modules/webaudio/AudioNodeOutput.cpp

DEFINITIONS

1. m_renderingParamFanOutCount
2. setNumberOfChannels
3. updateInternalBus
4. updateRenderingState
5. updateNumberOfChannels
6. propagateChannelCount
7. pull
8. bus
9. fanOutCount
10. paramFanOutCount
11. renderingFanOutCount
12. addInput
13. removeInput
14. disconnectAllInputs
15. addParam
16. removeParam
17. disconnectAllParams
18. disconnectAll
19. disable
20. enable

/*
 * 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
 *    notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 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 FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "modules/webaudio/AudioNodeOutput.h"

#include "modules/webaudio/AudioContext.h"
#include "modules/webaudio/AudioNodeInput.h"
#include "wtf/Threading.h"

namespace WebCore {

AudioNodeOutput::AudioNodeOutput(AudioNode* node, unsigned numberOfChannels)
    : m_node(node)
    , m_numberOfChannels(numberOfChannels)
    , m_desiredNumberOfChannels(numberOfChannels)
    , m_isInPlace(false)
    , m_isEnabled(true)
    , m_renderingFanOutCount(0)
    , m_renderingParamFanOutCount(0)
{
    ASSERT(numberOfChannels <= AudioContext::maxNumberOfChannels());

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

void AudioNodeOutput::setNumberOfChannels(unsigned numberOfChannels)
{
    ASSERT(numberOfChannels <= AudioContext::maxNumberOfChannels());
    ASSERT(context()->isGraphOwner());

    m_desiredNumberOfChannels = numberOfChannels;

    if (context()->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 {
        // Let the context take care of it in the audio thread in the pre and post render tasks.
        context()->markAudioNodeOutputDirty(this);
    }
}

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

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

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

void AudioNodeOutput::updateNumberOfChannels()
{
    ASSERT(context()->isAudioThread() && context()->isGraphOwner());

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

void AudioNodeOutput::propagateChannelCount()
{
    ASSERT(context()->isAudioThread() && context()->isGraphOwner());

    if (isChannelCountKnown()) {
        // Announce to any nodes we're connected to that we changed our channel count for its input.
        for (InputsIterator i = m_inputs.begin(); i != m_inputs.end(); ++i) {
            AudioNodeInput* input = *i;
            AudioNode* connectionNode = input->node();
            connectionNode->checkNumberOfChannelsForInput(input);
        }
    }
}

AudioBus* AudioNodeOutput::pull(AudioBus* inPlaceBus, size_t framesToProcess)
{
    ASSERT(context()->isAudioThread());
    ASSERT(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;

    node()->processIfNecessary(framesToProcess);
    return bus();
}

AudioBus* AudioNodeOutput::bus() const
{
    ASSERT(const_cast<AudioNodeOutput*>(this)->context()->isAudioThread());
    return m_isInPlace ? m_inPlaceBus.get() : m_internalBus.get();
}

unsigned AudioNodeOutput::fanOutCount()
{
    ASSERT(context()->isGraphOwner());
    return m_inputs.size();
}

unsigned AudioNodeOutput::paramFanOutCount()
{
    ASSERT(context()->isGraphOwner());
    return m_params.size();
}

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

void AudioNodeOutput::addInput(AudioNodeInput* input)
{
    ASSERT(context()->isGraphOwner());

    ASSERT(input);
    if (!input)
        return;

    m_inputs.add(input);
}

void AudioNodeOutput::removeInput(AudioNodeInput* input)
{
    ASSERT(context()->isGraphOwner());

    ASSERT(input);
    if (!input)
        return;

    m_inputs.remove(input);
}

void AudioNodeOutput::disconnectAllInputs()
{
    ASSERT(context()->isGraphOwner());

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

void AudioNodeOutput::addParam(AudioParam* param)
{
    ASSERT(context()->isGraphOwner());

    ASSERT(param);
    if (!param)
        return;

    m_params.add(param);
}

void AudioNodeOutput::removeParam(AudioParam* param)
{
    ASSERT(context()->isGraphOwner());

    ASSERT(param);
    if (!param)
        return;

    m_params.remove(param);
}

void AudioNodeOutput::disconnectAllParams()
{
    ASSERT(context()->isGraphOwner());

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

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

void AudioNodeOutput::disable()
{
    ASSERT(context()->isGraphOwner());

    if (m_isEnabled) {
        for (InputsIterator i = m_inputs.begin(); i != m_inputs.end(); ++i) {
            AudioNodeInput* input = *i;
            input->disable(this);
        }
        m_isEnabled = false;
    }
}

void AudioNodeOutput::enable()
{
    ASSERT(context()->isGraphOwner());

    if (!m_isEnabled) {
        for (InputsIterator i = m_inputs.begin(); i != m_inputs.end(); ++i) {
            AudioNodeInput* input = *i;
            input->enable(this);
        }
        m_isEnabled = true;
    }
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)