Source/WebCore/Modules/webaudio/AudioDestinationNode.h

/*
 * 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.
 */

#pragma once

#include "AudioBus.h"
#include "AudioIOCallback.h"
#include "AudioNode.h"
#include <wtf/Function.h>

namespace WebCore {

class AudioContext;

class AudioDestinationNode : public AudioNode, public AudioIOCallback {
    WTF_MAKE_ISO_ALLOCATED(AudioDestinationNode);
public:
    AudioDestinationNode(AudioContext&, float sampleRate);
    virtual ~AudioDestinationNode();
    
    // AudioNode   
    void process(size_t) override { }; // we're pulled by hardware so this is never called
    void reset() override { m_currentSampleFrame = 0; }
    
    // The audio hardware calls render() to get the next render quantum of audio into destinationBus.
    // It will optionally give us local/live audio input in sourceBus (if it's not 0).
    void render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames) override;

    size_t currentSampleFrame() const { return m_currentSampleFrame; }
    double currentTime() const { return currentSampleFrame() / static_cast<double>(sampleRate()); }

    virtual unsigned maxChannelCount() const { return 0; }

    // Enable local/live input for the specified device.
    virtual void enableInput(const String& inputDeviceId) = 0;

    virtual void startRendering() = 0;
    virtual void resume(WTF::Function<void ()>&&) { }
    virtual void suspend(WTF::Function<void ()>&&) { }
    virtual void close(WTF::Function<void ()>&&) { }

    virtual bool isPlaying() { return false; }
    void isPlayingDidChange() override;
    bool isPlayingAudio() const { return m_isEffectivelyPlayingAudio; }
    void setMuted(bool muted) { m_muted = muted; }

protected:
    double tailTime() const override { return 0; }
    double latencyTime() const override { return 0; }

    void setIsSilent(bool);
    void updateIsEffectivelyPlayingAudio();

    // Counts the number of sample-frames processed by the destination.
    size_t m_currentSampleFrame;

    bool m_isSilent;
    bool m_isEffectivelyPlayingAudio;
    bool m_muted;
};

} // namespace WebCore