Source/WebCore/Modules/webaudio/OfflineAudioDestinationNode.h

/*
 * Copyright (C) 2011, Google Inc. All rights reserved.
 * Copyright (C) 2020-2021, Apple Inc. 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.
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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
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 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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#pragma once

#include "AudioDestinationNode.h"
#include <wtf/RefPtr.h>
#include <wtf/Threading.h>

namespace WebCore {

class AudioBuffer;
class AudioBus;
class OfflineAudioContext;
    
class OfflineAudioDestinationNode final : public AudioDestinationNode {
    WTF_MAKE_ISO_ALLOCATED(OfflineAudioDestinationNode);
public:
    OfflineAudioDestinationNode(OfflineAudioContext&, unsigned numberOfChannels, float sampleRate, RefPtr<AudioBuffer>&& renderTarget);
    ~OfflineAudioDestinationNode();

    OfflineAudioContext& context();
    const OfflineAudioContext& context() const;

    AudioBuffer* renderTarget() const { return m_renderTarget.get(); }
    
    // AudioNode   
    void initialize() final;
    void uninitialize() final;

    // AudioDestinationNode
    void enableInput(const String&) final { }
    void startRendering(CompletionHandler<void(std::optional<Exception>&&)>&&) final;

private:
    enum class RenderResult { Failure, Suspended, Complete };
    RenderResult renderOnAudioThread();
    void notifyOfflineRenderingSuspended();

    bool requiresTailProcessing() const final { return false; }

    unsigned maxChannelCount() const final { return m_numberOfChannels; }

    unsigned m_numberOfChannels;

    // This AudioNode renders into this AudioBuffer.
    RefPtr<AudioBuffer> m_renderTarget;
    
    // Temporary AudioBus for each render quantum.
    RefPtr<AudioBus> m_renderBus;
    
    // Rendering thread.
    RefPtr<Thread> m_renderThread;
    size_t m_framesToProcess;
    size_t m_destinationOffset { 0 };
    bool m_startedRendering { false };
};

} // namespace WebCore