qv4l2memorytransfer_p.h

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// Copyright (C) 2023 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 QV4L2MEMORYTRANSFER_P_H

#define QV4L2MEMORYTRANSFER_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/qabstractvideobuffer.h>

#include <QtMultimedia/private/qtmultimediaglobal_p.h>

#include <QtCore/qtypes.h>

#include <QtCore/private/qexpected_p.h>

#include <linux/videodev2.h>

#include <sys/time.h>

#include <memory>

#include <optional>

QT_BEGIN_NAMESPACE

namespace QtV4L2 {

class QV4L2FileDescriptor;

using QV4L2FileDescriptorPtr = std::shared_ptr<QV4L2FileDescriptor>;

class QV4L2MemoryTransfer

public:

    struct Frame

        timeval timestamp = {};

        std::unique_ptr<QAbstractVideoBuffer> videoBuffer;

};

    QV4L2MemoryTransfer(QV4L2FileDescriptorPtr fileDescriptor);

    virtual ~QV4L2MemoryTransfer();

    virtual std::optional<Frame> dequeueFrame() = 0;

    virtual quint32 buffersCount() const = 0;

protected:

    virtual bool enqueueBuffer(quint32 index) = 0;

    bool enqueueBuffers();

    q23::expected<int, std::error_code> ioctl(int request, void *arg);

    const QV4L2FileDescriptor &fileDescriptor() const { return *m_fileDescriptor; }

private:

    QV4L2FileDescriptorPtr m_fileDescriptor;

};

using QV4L2MemoryTransferUPtr = std::unique_ptr<QV4L2MemoryTransfer>;

QV4L2MemoryTransferUPtr makeUserPtrMemoryTransfer(QV4L2FileDescriptorPtr fileDescriptor,

                                                  quint32 imageSize, int bytesPerLine);

QV4L2MemoryTransferUPtr makeMMapMemoryTransfer(QV4L2FileDescriptorPtr fileDescriptor,

                                               int bytesPerLine);

} // namespace QtV4L2

QT_END_NAMESPACE

#endif // QV4L2MEMORYTRANSFER_P_H