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,
                                                  const v4l2_pix_format &format);
 
QV4L2MemoryTransferUPtr makeMMapMemoryTransfer(QV4L2FileDescriptorPtr fileDescriptor,
                                               const v4l2_pix_format &format);
 
#if QT_CONFIG(linux_dmabuf)
QV4L2MemoryTransferUPtr makeDmaBufMemoryTransfer(const QV4L2FileDescriptorPtr &fileDescriptor,
                                                 const v4l2_pix_format &format);
#endif
 
} // namespace QtV4L2
 
QT_END_NAMESPACE
 
#endif // QV4L2MEMORYTRANSFER_P_H