qwasmwebaudiosink_p.h

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// Copyright (C) 2026 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#ifndef QWASMWEBAUDIOSINK_P_H

#define QWASMWEBAUDIOSINK_P_H

//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API.  It exists purely as an

// implementation detail.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

//

#include <private/qaudiosystem_p.h>

#include <QHash>

#include <emscripten/val.h>

#include <atomic>

#include <optional>

#include <string>

QT_BEGIN_NAMESPACE

class QWasmAudioSinkDevice;

class QWasmAudioSink : public QPlatformAudioSink

    Q_OBJECT

public:

    QWasmAudioSink(QAudioDevice, const QAudioFormat &, QObject *parent);

    ~QWasmAudioSink() override;

    void start(QIODevice *device) override;

    QIODevice *start() override;

    void start(AudioCallback &&callback) override;

    bool hasCallbackAPI() override { return true; }

    void stop() override;

    void reset() override;

    void suspend() override;

    void resume() override;

    qsizetype bytesFree() const override;

    void setBufferSize(qsizetype value) override;

    qsizetype bufferSize() const override;

    qint64 processedUSecs() const override;

    QAudio::State state() const override;

    void setVolume(float volume) override;

    void setError(QAudio::Error) override;

    static void workletReadyCallback(int callbackId);

    static void deliverDataCallback(int callbackId);

private:

    void start(bool pullMode);

    void deliverData();

    void connectWorklet();

    void writeToRingBuffer(const char *data, int bytes);

    void teardownPipeline();

#if !QT_CONFIG(thread)

    void deliverToWorklet();

#endif

    static int s_nextId;

    int m_callbackId = 0;

    emscripten::val m_audioContext = emscripten::val::undefined();

#if QT_CONFIG(thread)

    std::atomic<int> m_activeCallbackId{0};

#endif

    std::atomic<quint64> m_processed{0};

    bool m_workletModuleLoaded = false;

    emscripten::val m_workletNode = emscripten::val::undefined();

    // Ring buffer: main thread writes, worklet reads (threaded) or

    // deliverToWorklet() reads and posts (single-threaded).

    QByteArray m_ringBuffer;

    std::atomic<int> m_writePos{0};

    std::atomic<int> m_readPos{0};

    std::atomic<float> m_volumeAtomic{1.0f};

    QIODevice *m_device = nullptr;

    bool m_pullMode = false;

    bool m_running = false;

    bool m_suspended = false;

    std::optional<AudioCallback> m_audioCallback;

    qsizetype m_bufferSize = 0;

    std::string m_deviceId;

    friend class QWasmAudioSinkDevice;

};

QT_END_NAMESPACE

#endif // QWASMWEBAUDIOSINK_P_H