xref: /external/webkit/Source/WebCore/webaudio/AudioBasicProcessorNode.cpp

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 * Copyright (C) 2010, Google Inc. All rights reserved.
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#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "AudioBasicProcessorNode.h"

#include "AudioBus.h"
#include "AudioContext.h"
#include "AudioNodeInput.h"
#include "AudioNodeOutput.h"
#include "AudioProcessor.h"

namespace WebCore {

AudioBasicProcessorNode::AudioBasicProcessorNode(AudioContext* context, double sampleRate)
    : AudioNode(context, sampleRate)
{
    addInput(adoptPtr(new AudioNodeInput(this)));
    addOutput(adoptPtr(new AudioNodeOutput(this, 0)));

    // The subclass must create m_processor.
}

void AudioBasicProcessorNode::initialize()
{
    if (isInitialized())
        return;

    ASSERT(processor());
    processor()->initialize();

    AudioNode::initialize();
}

void AudioBasicProcessorNode::uninitialize()
{
    if (!isInitialized())
        return;

    ASSERT(processor());
    processor()->uninitialize();

    AudioNode::uninitialize();
}

void AudioBasicProcessorNode::process(size_t framesToProcess)
{
    AudioBus* destinationBus = output(0)->bus();

    // The realtime thread can't block on this lock, so we call tryLock() instead.
    if (m_processLock.tryLock()) {
        if (!isInitialized() || !processor())
            destinationBus->zero();
        else {
            AudioBus* sourceBus = input(0)->bus();

            // FIXME: if we take "tail time" into account, then we can avoid calling processor()->process() once the tail dies down.
            if (!input(0)->isConnected())
                sourceBus->zero();

            processor()->process(sourceBus, destinationBus, framesToProcess);
        }

        m_processLock.unlock();
    } else {
        // Too bad - the tryLock() failed.  We must be in the middle of re-connecting and were already outputting silence anyway...
        destinationBus->zero();
    }
}

// Nice optimization in the very common case allowing for "in-place" processing
void AudioBasicProcessorNode::pullInputs(size_t framesToProcess)
{
    // Render input stream - suggest to the input to render directly into output bus for in-place processing in process() if possible.
    input(0)->pull(output(0)->bus(), framesToProcess);
}

void AudioBasicProcessorNode::reset()
{
    if (processor())
        processor()->reset();
}

// As soon as we know the channel count of our input, we can lazily initialize.
// Sometimes this may be called more than once with different channel counts, in which case we must safely
// uninitialize and then re-initialize with the new channel count.
void AudioBasicProcessorNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
{
    ASSERT(context()->isAudioThread() && context()->isGraphOwner());

    ASSERT(input == this->input(0));
    if (input != this->input(0))
        return;

    ASSERT(processor());
    if (!processor())
        return;

    unsigned numberOfChannels = input->numberOfChannels();

    if (isInitialized() && numberOfChannels != output(0)->numberOfChannels()) {
        // We're already initialized but the channel count has changed.
        // We need to be careful since we may be actively processing right now, so synchronize with process().
        MutexLocker locker(m_processLock);
        uninitialize();
    }

    if (!isInitialized()) {
        // This will propagate the channel count to any nodes connected further down the chain...
        output(0)->setNumberOfChannels(numberOfChannels);

        // Re-initialize the processor with the new channel count.
        processor()->setNumberOfChannels(numberOfChannels);
        initialize();
    }
}

unsigned AudioBasicProcessorNode::numberOfChannels()
{
    return output(0)->numberOfChannels();
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)