AudioBasicInspectorNode.cpp   [plain text]

/*
 * Copyright (C) 2012, Intel Corporation. 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
 *    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;
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#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "AudioBasicInspectorNode.h"

#include "AudioNodeInput.h"
#include "AudioNodeOutput.h"

namespace WebCore {

AudioBasicInspectorNode::AudioBasicInspectorNode(AudioContext& context, float sampleRate, unsigned outputChannelCount)
    : AudioNode(context, sampleRate)
{
    addInput(std::make_unique<AudioNodeInput>(this));
    addOutput(std::make_unique<AudioNodeOutput>(this, outputChannelCount));
}

// We override pullInputs() as an optimization allowing this node to take advantage of in-place processing,
// where the input is simply passed through unprocessed to the output.
// Note: this only applies if the input and output channel counts match.
void AudioBasicInspectorNode::pullInputs(size_t framesToProcess)
{
    // Render input stream - try to render directly into output bus for pass-through processing where process() doesn't need to do anything...
    input(0)->pull(output(0)->bus(), framesToProcess);
}

ExceptionOr<void> AudioBasicInspectorNode::connect(AudioNode& destination, unsigned outputIndex, unsigned inputIndex)
{
    ASSERT(isMainThread());

    AudioContext::AutoLocker locker(context());

    auto result = AudioNode::connect(destination, outputIndex, inputIndex);
    updatePullStatus();
    return result;
}

ExceptionOr<void> AudioBasicInspectorNode::disconnect(unsigned outputIndex)
{
    ASSERT(isMainThread());

    AudioContext::AutoLocker locker(context());

    auto result = AudioNode::disconnect(outputIndex);
    updatePullStatus();
    return result;
}

void AudioBasicInspectorNode::checkNumberOfChannelsForInput(AudioNodeInput* input)
{
    ASSERT(context().isAudioThread() && context().isGraphOwner());

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

    unsigned numberOfChannels = input->numberOfChannels();

    if (numberOfChannels != output(0)->numberOfChannels()) {
        // This will propagate the channel count to any nodes connected further downstream in the graph.
        output(0)->setNumberOfChannels(numberOfChannels);
    }

    AudioNode::checkNumberOfChannelsForInput(input);

    updatePullStatus();
}

void AudioBasicInspectorNode::updatePullStatus()
{
    ASSERT(context().isGraphOwner());

    if (output(0)->isConnected()) {
        // When an AudioBasicInspectorNode is connected to a downstream node, it will get pulled by the
        // downstream node, thus remove it from the context's automatic pull list.
        if (m_needAutomaticPull) {
            context().removeAutomaticPullNode(this);
            m_needAutomaticPull = false;
        }
    } else {
        unsigned numberOfInputConnections = input(0)->numberOfRenderingConnections();
        if (numberOfInputConnections && !m_needAutomaticPull) {
            // When an AudioBasicInspectorNode is not connected to any downstream node while still connected from
            // upstream node(s), add it to the context's automatic pull list.
            context().addAutomaticPullNode(this);
            m_needAutomaticPull = true;
        } else if (!numberOfInputConnections && m_needAutomaticPull) {
            // The AudioBasicInspectorNode is connected to nothing, remove it from the context's automatic pull list.
            context().removeAutomaticPullNode(this);
            m_needAutomaticPull = false;
        }
    }
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)