axmol/thirdparty/yasio/impl/pipe_select_interrupter.hpp

128 lines
3.5 KiB
C++

//////////////////////////////////////////////////////////////////////////////////////////
// A multi-platform support c++11 library with focus on asynchronous socket I/O for any
// client application.
//////////////////////////////////////////////////////////////////////////////////////////
//
//
// Copyright (c) 2012-2023 HALX99 (halx99 at live dot com)
// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
// Copyright (c) 2008 Roelof Naude (roelof.naude at gmail dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// see also: https://github.com/chriskohlhoff/asio
//
#ifndef YASIO__PIPE_SELECT_INTERRUPTER_HPP
#define YASIO__PIPE_SELECT_INTERRUPTER_HPP
#include "yasio/compiler/feature_test.hpp"
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
namespace yasio
{
YASIO__NS_INLINE
namespace inet
{
class pipe_select_interrupter {
public:
// Constructor.
inline pipe_select_interrupter() { open_descriptors(); }
// Destructor.
inline ~pipe_select_interrupter() { close_descriptors(); }
// Recreate the interrupter's descriptors. Used after a fork.
inline void recreate()
{
close_descriptors();
write_descriptor_ = -1;
read_descriptor_ = -1;
open_descriptors();
}
// Interrupt the select call.
inline void interrupt()
{
char byte = 0;
auto result = ::write(write_descriptor_, &byte, 1);
(void)result;
}
// Reset the select interrupter. Returns true if the reset was successful.
inline bool reset()
{
char data[1024];
for (;;)
{
// Clear all data from the pipe.
int bytes_read = static_cast<int>(::read(read_descriptor_, data, sizeof(data)));
if (bytes_read == sizeof(data))
continue;
if (bytes_read > 0)
return true;
if (bytes_read == 0)
return false;
int ec = errno;
if (ec == EINTR)
continue;
return (ec == EWOULDBLOCK || ec == EAGAIN);
}
}
// Get the read descriptor to be passed to select.
int read_descriptor() const { return read_descriptor_; }
private:
// Open the descriptors. Throws on error.
inline void open_descriptors()
{
int pipe_fds[2];
if (pipe(pipe_fds) == 0)
{
read_descriptor_ = pipe_fds[0];
::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
write_descriptor_ = pipe_fds[1];
::fcntl(write_descriptor_, F_SETFL, O_NONBLOCK);
#if defined(FD_CLOEXEC)
::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
::fcntl(write_descriptor_, F_SETFD, FD_CLOEXEC);
#endif // defined(FD_CLOEXEC)
}
else
yasio__throw_error(errno, "pipe_select_interrupter");
}
// Close the descriptors.
inline void close_descriptors()
{
if (read_descriptor_ != -1)
::close(read_descriptor_);
if (write_descriptor_ != -1)
::close(write_descriptor_);
}
// The read end of a connection used to interrupt the select call. This file
// descriptor is passed to select such that when it is time to stop, a single
// byte will be written on the other end of the connection and this
// descriptor will become readable.
int read_descriptor_;
// The write end of a connection used to interrupt the select call. A single
// byte may be written to this to wake up the select which is waiting for the
// other end to become readable.
int write_descriptor_;
};
} // namespace inet
} // namespace yasio
#endif // YASIO__PIPE_SELECT_INTERRUPTER_HPP