unique_fd.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Google Inc.
 *
 * File descriptor wrapper that owns a file descriptor.
 */

#pragma once

#include <utility>

#include <libcamera/base/class.h>
#include <libcamera/base/compiler.h>

namespace libcamera {

class UniqueFD final
{
public:
    UniqueFD()
        : fd_(-1)
    {
    }

    explicit UniqueFD(int fd)
        : fd_(fd)
    {
    }

    UniqueFD(UniqueFD &&other)
        : fd_(other.release())
    {
    }

    ~UniqueFD()
    {
        reset();
    }

    UniqueFD &operator=(UniqueFD &&other)
    {
        reset(other.release());
        return *this;
    }

    __nodiscard int release()
    {
        int fd = fd_;
        fd_ = -1;
        return fd;
    }

    void reset(int fd = -1);

    void swap(UniqueFD &other)
    {
        std::swap(fd_, other.fd_);
    }

    int get() const { return fd_; }
    bool isValid() const { return fd_ >= 0; }

private:
    LIBCAMERA_DISABLE_COPY(UniqueFD)

    int fd_;
};

} /* namespace libcamera */