shared_fd.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * File descriptor wrapper with shared ownership
 */
 
#pragma once
 
#include <memory>
 
namespace libcamera {
 
class UniqueFD;
 
class SharedFD final
{
public:
    explicit SharedFD(const int &fd = -1);
    explicit SharedFD(int &&fd);
    explicit SharedFD(UniqueFD fd);
    SharedFD(const SharedFD &other);
    SharedFD(SharedFD &&other);
    ~SharedFD();
 
    SharedFD &operator=(const SharedFD &other);
    SharedFD &operator=(SharedFD &&other);
 
    bool isValid() const { return fd_ != nullptr; }
    int get() const { return fd_ ? fd_->fd() : -1; }
    UniqueFD dup() const;
 
private:
    class Descriptor
    {
    public:
        Descriptor(int fd, bool duplicate);
        ~Descriptor();
 
        int fd() const { return fd_; }
 
    private:
        int fd_;
    };
 
    std::shared_ptr<Descriptor> fd_;
};
 
static inline bool operator==(const SharedFD &lhs, const SharedFD &rhs)
{
    return lhs.get() == rhs.get();
}
 
static inline bool operator!=(const SharedFD &lhs, const SharedFD &rhs)
{
    return !(lhs == rhs);
}
 
} /* namespace libcamera */