qpipewire_audiodevicemonitor_p.h

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// Copyright (C) 2025 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 QPIPEWIRE_AUDIODEVICEMONITOR_P_H
#define QPIPEWIRE_AUDIODEVICEMONITOR_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 <QtMultimedia/private/qpipewire_async_support_p.h>
#include <QtMultimedia/private/qpipewire_propertydict_p.h>
#include <QtMultimedia/private/qpipewire_registry_support_p.h>
#include <QtMultimedia/private/qpipewire_spa_pod_support_p.h>
#include <QtMultimedia/qaudiodevice.h>
#include <QtCore/qchronotimer.h>
#include <QtCore/qfuture.h>
#include <QtCore/qreadwritelock.h>
 
#include <list>
#include <vector>
 
#include <pipewire/pipewire.h>
 
QT_BEGIN_NAMESPACE
 
namespace QtPipeWire {
 
class ObjectRemoveObserver : public QObject
{
    Q_OBJECT
public:
    explicit ObjectRemoveObserver(ObjectSerial objectSerial);
    ObjectSerial serial() const;
 
signals:
    void objectRemoved();
 
private:
    const ObjectSerial m_observedSerial;
};
 
using SharedObjectRemoveObserver = std::shared_ptr<ObjectRemoveObserver>;
 
// TODO: can we make use of COW here?
class QAudioDeviceMonitor : public QObject
{
    Q_OBJECT
 
    enum class Direction : uint8_t
    {
        sink,
        source,
    };
 
public:
    QAudioDeviceMonitor();
    ~QAudioDeviceMonitor();
 
    void objectAdded(ObjectId, uint32_t permissions, PipewireRegistryType, uint32_t version,
                     const spa_dict &props);
    void objectRemoved(ObjectId);
 
    struct NoDefaultDeviceType
    {
    };
    static constexpr NoDefaultDeviceType NoDefaultDevice{};
    void setDefaultAudioSink(std::variant<QByteArray, NoDefaultDeviceType>);
    void setDefaultAudioSource(std::variant<QByteArray, NoDefaultDeviceType>);
 
    std::optional<ObjectSerial> findSinkNodeSerial(std::string_view nodeName) const;
    std::optional<ObjectSerial> findSourceNodeSerial(std::string_view nodeName) const;
 
    // ObjectId/ObjectSerial mapping
    std::optional<ObjectId> findObjectId(ObjectSerial) const;
    std::optional<ObjectSerial> findObjectSerial(ObjectId) const;
 
    [[nodiscard]] bool registerObserver(SharedObjectRemoveObserver);
    void unregisterObserver(const SharedObjectRemoveObserver &);
    void clearAllObservers();
 
    // Obtaining device lists
    struct DeviceLists
    {
        QList<QAudioDevice> sources;
        QList<QAudioDevice> sinks;
    };
    DeviceLists getDeviceLists(bool verifyThreading = true);
 
signals:
    void audioSinksChanged(QList<QAudioDevice>);
    void audioSourcesChanged(QList<QAudioDevice>);
 
private:
    struct DeviceRecord
    {
        ObjectSerial serial;
        PwPropertyDict properties;
    };
 
    struct PendingNodeRecord
    {
        PendingNodeRecord(ObjectId, ObjectSerial serial, std::optional<ObjectSerial> deviceSerial,
                          PwPropertyDict properties);
 
        ObjectSerial serial;
        std::optional<ObjectSerial> deviceSerial; // may be nullopt for virtual nodes
        PwPropertyDict properties;
        std::unique_ptr<NodeEventListener> enumFormatListener;
        std::unique_ptr<CoreEventDoneListener> enumFormatDoneListener;
        QFuture<std::vector<SpaObjectAudioFormat>> formatFuture;
 
        // owned by he instance, updated in the formatFuture's continuation (we capture a weak reference in the
        // continuation to avoid lifetime issues
        const std::shared_ptr<std::optional<std::vector<SpaObjectAudioFormat>>> formatResults;
    };
 
    struct NodeRecord
    {
        ObjectSerial serial;
        std::optional<ObjectSerial> deviceSerial; // may be nullopt for virtual nodes
        PwPropertyDict properties;
        SpaObjectAudioFormat format;
    };
 
    // discovered, but format not resolved
    struct PendingRecords
    {
        std::list<PendingNodeRecord> m_sources;
        std::list<PendingNodeRecord> m_sinks;
        std::vector<ObjectSerial> m_removals;
 
        std::optional<std::variant<QByteArray, NoDefaultDeviceType>> m_defaultSource;
        std::optional<std::variant<QByteArray, NoDefaultDeviceType>> m_defaultSink;
 
        void removeRecordsForObject(ObjectSerial);
    };
    QMutex m_pendingRecordsMutex;
    PendingRecords m_pendingRecords QT_MM_GUARDED_BY(m_pendingRecordsMutex);
 
    // discovered, format resolved. living on application thread
    mutable QReadWriteLock m_mutex;
    std::map<ObjectSerial, DeviceRecord> m_devices QT_MM_GUARDED_BY(m_mutex);
    std::vector<NodeRecord> m_sources QT_MM_GUARDED_BY(m_mutex);
    std::vector<NodeRecord> m_sinks QT_MM_GUARDED_BY(m_mutex);
    std::optional<QByteArray> m_defaultSourceName;
    std::optional<QByteArray> m_defaultSinkName;
 
    QThread m_compressionTimerThread{ this };
    QChronoTimer m_compressionTimer;
    void startCompressionTimer();
 
    // Device list updates
    void audioDevicesChanged(bool verifyThreading = true);
    void updateSources(std::list<PendingNodeRecord> addedNodes,
                       QSpan<const ObjectSerial> removedObjects);
    void updateSinks(std::list<PendingNodeRecord> addedNodes,
                     QSpan<const ObjectSerial> removedObjects);
    template <Direction>
    void updateSourcesOrSinks(std::list<PendingNodeRecord>, QSpan<const ObjectSerial>);
 
    QList<QAudioDevice> m_sourceDeviceList;
    QList<QAudioDevice> m_sinkDeviceList;
 
    std::optional<ObjectSerial> findDeviceSerial(std::string_view deviceName) const;
 
    template <Direction>
    std::optional<ObjectSerial> findNodeSerialForNodeName(std::string_view nodeName) const;
 
    // ObjectId/ObjectSerial mapping
    // CHECK: can we completely rely on only accessing ObjectId under the pipewire event loop lock?
    mutable QReadWriteLock m_objectDictMutex;
    std::map<ObjectId, ObjectSerial> m_objectSerialDict QT_MM_GUARDED_BY(m_objectDictMutex);
    std::map<ObjectSerial, ObjectId> m_serialObjectDict QT_MM_GUARDED_BY(m_objectDictMutex);
 
    std::vector<SharedObjectRemoveObserver>
            m_objectRemoveObserver QT_MM_GUARDED_BY(m_objectDictMutex);
};
 
} // namespace QtPipeWire
 
QT_END_NAMESPACE
 
#endif // QPIPEWIRE_AUDIODEVICEMONITOR_P_H