Source/WebCore/Modules/webaudio/MediaElementAudioSourceNode.h

/*
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 * Copyright (C) 2020, Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
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#pragma once

#if ENABLE(WEB_AUDIO) && ENABLE(VIDEO)

#include "AudioNode.h"
#include "AudioSourceProviderClient.h"
#include "HTMLMediaElement.h"
#include "MultiChannelResampler.h"
#include <memory>
#include <wtf/Lock.h>

namespace WebCore {

class AudioContext;
struct MediaElementAudioSourceOptions;
    
class MediaElementAudioSourceNode final : public AudioNode, public AudioSourceProviderClient {
    WTF_MAKE_ISO_ALLOCATED(MediaElementAudioSourceNode);
public:
    static ExceptionOr<Ref<MediaElementAudioSourceNode>> create(BaseAudioContext&, MediaElementAudioSourceOptions&&);

    virtual ~MediaElementAudioSourceNode();

    HTMLMediaElement& mediaElement() { return m_mediaElement; }

    // AudioNode
    void process(size_t framesToProcess) override;
    
    // AudioSourceProviderClient
    void setFormat(size_t numberOfChannels, float sampleRate) override;

    Lock& processLock() WTF_RETURNS_LOCK(m_processLock) { return m_processLock; }

private:
    MediaElementAudioSourceNode(BaseAudioContext&, Ref<HTMLMediaElement>&&);
    void provideInput(AudioBus*, size_t framesToProcess);

    double tailTime() const override { return 0; }
    double latencyTime() const override { return 0; }
    bool requiresTailProcessing() const final { return false; }

    // As an audio source, we will never propagate silence.
    bool propagatesSilence() const override { return false; }

    bool wouldTaintOrigin();

    Ref<HTMLMediaElement> m_mediaElement;
    Lock m_processLock;

    unsigned m_sourceNumberOfChannels WTF_GUARDED_BY_LOCK(m_processLock) { 0 };
    double m_sourceSampleRate WTF_GUARDED_BY_LOCK(m_processLock) { 0 };
    bool m_muted WTF_GUARDED_BY_LOCK(m_processLock) { false };

    std::unique_ptr<MultiChannelResampler> m_multiChannelResampler WTF_GUARDED_BY_LOCK(m_processLock);
};

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO) && ENABLE(VIDEO)