Source/WebCore/Modules/webaudio/AudioBasicInspectorNode.cpp

/*
 * 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
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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 FOR ANY
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#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "AudioBasicInspectorNode.h"

#include "AudioNodeInput.h"
#include "AudioNodeOutput.h"
#include <wtf/IsoMallocInlines.h>

namespace WebCore {

WTF_MAKE_ISO_ALLOCATED_IMPL(AudioBasicInspectorNode);

AudioBasicInspectorNode::AudioBasicInspectorNode(BaseAudioContext& context, NodeType type)
    : AudioNode(context, type)
{
    addInput();
}

// 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...
    auto* output = this->output(0);
    input(0)->pull(output ? output->bus() : nullptr, framesToProcess);
}

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

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

    if (auto* output = this->output(0)) {
        unsigned numberOfChannels = input->numberOfChannels();

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

    AudioNode::checkNumberOfChannelsForInput(input);

    updatePullStatus();
}

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

    auto output = this->output(0);
    if (output && output->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 and is not an AnalyserNode, remove it from the
            // context's automatic pull list. AnalyserNode's need to be pulled even with no inputs so that the
            // internal state gets updated to hold the right time and FFT data.
            context().removeAutomaticPullNode(*this);
            m_needAutomaticPull = false;
        }
    }
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)