qwasmwebaudiosource_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 QWASMWEBAUDIOSOURCE_P_H

#define QWASMWEBAUDIOSOURCE_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 <QElapsedTimer>

#include <QHash>

#include <emscripten/val.h>

#include "qwasmjs_p.h"

#if QT_CONFIG(thread)

#  include <atomic>

#endif

QT_BEGIN_NAMESPACE

class QWasmAudioSourceDevice;

class QWasmAudioSource : public QPlatformAudioSource

    Q_OBJECT

public:

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

    ~QWasmAudioSource() override;

    void start(QIODevice *device) override;

    QIODevice *start() override;

    void stop() override;

    void reset() override;

    void suspend() override;

    void resume() override;

    qsizetype bytesReady() 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;

    qint64 readFromBuffer(char *data, qint64 maxlen);

    static void workletReadyCallback(int callbackId);

    static void audioDataCallback(int callbackId);

private:

    void startPipeline(bool pullMode);

    void connectMediaStreamIfReady();

    void deliverBufferedData();

    void teardownPipeline();

#if QT_CONFIG(thread)

    // Threaded path: JS AudioWorklet writes directly into the WASM heap

    // (SharedArrayBuffer) via the SPSC ring buffer.

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

    QByteArray m_ringBuffer;

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

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

    std::atomic<bool> m_running{false};

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

#else // QT_CONFIG(thread)

    // Single-threaded path: JS AudioWorklet + MessagePort.

    // No SharedArrayBuffer — frames arrive via postMessage into a JS-side queue,

    // drained by postMessage callbacks into m_pendingData (main-thread only).

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

    QByteArray m_pendingData;

    bool m_running = false;

#endif // QT_CONFIG(thread)

    // Common to both paths

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

    static int s_nextId;

    int m_callbackId = 0;

    JsMediaInputStream *m_inputStream = nullptr;

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

    bool m_streamReady = false;

    bool m_workletReady = false;

    QIODevice *m_device = nullptr;

    bool m_pullMode  = false;

    bool m_suspended = false;

    quint64 m_processed  = 0;

    qsizetype m_bufferSize = 0;

    QElapsedTimer m_elapsedTimer;

    friend class QWasmAudioSourceDevice;

};

QT_END_NAMESPACE

#endif // QWASMWEBAUDIOSOURCE_P_H