qdmabufallocator_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 QDMABUFALLOCATOR_P_H
#define QDMABUFALLOCATOR_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/qtmultimediaglobal_p.h>
#include <QtCore/qstring.h>
#include <QtCore/private/qexpected_p.h>
#include <QtCore/private/quniquehandle_types_p.h>
 
#include <memory>
 
QT_BEGIN_NAMESPACE
 
namespace QtMultimediaPrivate {
 
// A DMA-BUF that owns its file descriptor. It does not refer to the allocator that
// created it, so it can outlive the allocator.
class Q_MULTIMEDIA_EXPORT QDmaBuf
{
public:
    QDmaBuf(QUniqueFileDescriptorHandle fd, qsizetype size);
 
    int fd() const { return m_fd.get(); }
    qsizetype size() const { return m_size; }
 
private:
    QUniqueFileDescriptorHandle m_fd;
    const qsizetype m_size = 0;
};
 
class Q_MULTIMEDIA_EXPORT QDmaBufAllocator
{
public:
    static q23::expected<QDmaBufAllocator, QString> create();
 
    q23::expected<std::shared_ptr<QDmaBuf>, QString> allocate(qsizetype size) const;
 
private:
    enum class Provider : uint8_t {
        DmaHeap, // /dev/dma_heap/system, may not be accessible as user
        UDmaBuf,
    };
 
    QDmaBufAllocator(QUniqueFileDescriptorHandle providerFd, Provider provider);
 
    QUniqueFileDescriptorHandle m_providerFd;
    const Provider m_provider;
};
 
} // namespace QtMultimediaPrivate
 
QT_END_NAMESPACE
 
#endif // QDMABUFALLOCATOR_P_H