filedescriptor.cpp

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/*
    KWin - the KDE window manager
    This file is part of the KDE project.
 
    SPDX-FileCopyrightText:: 2022 Xaver Hugl <xaver.hugl@gmail.com>
 
    SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "filedescriptor.h"
 
#include <fcntl.h>
#include <sys/poll.h>
#include <unistd.h>
#include <utility>
 
namespace KWin
{
 
FileDescriptor::FileDescriptor(int fd)
    : m_fd(fd)
{
}
 
FileDescriptor::FileDescriptor(FileDescriptor &&other)
    : m_fd(std::exchange(other.m_fd, -1))
{
}
 
FileDescriptor &FileDescriptor::operator=(FileDescriptor &&other)
{
    if (m_fd != -1) {
        ::close(m_fd);
    }
    m_fd = std::exchange(other.m_fd, -1);
    return *this;
}
 
FileDescriptor::~FileDescriptor()
{
    if (m_fd != -1) {
        ::close(m_fd);
    }
}
 
bool FileDescriptor::isValid() const
{
    return m_fd != -1;
}
 
int FileDescriptor::get() const
{
    return m_fd;
}
 
int FileDescriptor::take()
{
    return std::exchange(m_fd, -1);
}
 
void FileDescriptor::reset()
{
    if (m_fd != -1) {
        ::close(m_fd);
        m_fd = -1;
    }
}
 
FileDescriptor FileDescriptor::duplicate() const
{
    if (m_fd != -1) {
        return FileDescriptor{fcntl(m_fd, F_DUPFD_CLOEXEC, 0)};
    } else {
        return {};
    }
}
 
bool FileDescriptor::isClosed() const
{
    return isClosed(m_fd);
}
 
bool FileDescriptor::isReadable() const
{
    return isReadable(m_fd);
}
 
bool FileDescriptor::isClosed(int fd)
{
    pollfd pfd = {
        .fd = fd,
        .events = POLLIN,
        .revents = 0,
    };
    if (poll(&pfd, 1, 0) < 0) {
        return true;
    }
    return pfd.revents & (POLLHUP | POLLERR);
}
 
bool FileDescriptor::isReadable(int fd)
{
    pollfd pfd = {
        .fd = fd,
        .events = POLLIN,
        .revents = 0,
    };
    return poll(&pfd, 1, 0) && (pfd.revents & (POLLIN | POLLNVAL)) != 0;
}
}