axmol/thirdparty/yasio/detail/socket_select_interrupter.hpp

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//////////////////////////////////////////////////////////////////////////////////////////
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// A multi-platform support c++11 library with focus on asynchronous socket I/O for any
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// client application.
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//////////////////////////////////////////////////////////////////////////////////////////
//
// detail/socket_select_interrupter.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
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// Copyright (c) 2012-2021 halx99 (halx99 at live dot com)
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// 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__SOCKET_SELECT_INTERRUPTER_HPP
#define YASIO__SOCKET_SELECT_INTERRUPTER_HPP
#include "yasio/xxsocket.hpp"
namespace yasio
{
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YASIO__NS_INLINE
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namespace inet
{
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class socket_select_interrupter {
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public:
// Constructor.
inline socket_select_interrupter() { open_descriptors(); }
// Destructor.
inline ~socket_select_interrupter() { close_descriptors(); }
// Recreate the interrupter's descriptors. Used after a fork.
inline void recreate()
{
close_descriptors();
write_descriptor_ = invalid_socket;
read_descriptor_ = invalid_socket;
open_descriptors();
}
// Interrupt the select call.
inline void interrupt() { xxsocket::send(write_descriptor_, "\0", 1); }
// Reset the select interrupter. Returns true if the reset was successful.
inline bool reset()
{
char data[1024];
for (;;)
{
int bytes_read = xxsocket::recv(read_descriptor_, data, sizeof(data), 0);
if (bytes_read == sizeof(data))
continue;
if (bytes_read > 0)
return true;
if (bytes_read == 0)
return false;
int ec = xxsocket::get_last_errno();
if (ec == EINTR)
continue;
return (ec == EWOULDBLOCK || ec == EAGAIN);
}
}
// Get the read descriptor to be passed to select.
socket_native_type read_descriptor() const { return read_descriptor_; }
private:
// Open the descriptors. Throws on error.
inline void open_descriptors()
{
xxsocket acceptor(AF_INET, SOCK_STREAM, IPPROTO_TCP);
acceptor.set_optval(SOL_SOCKET, SO_REUSEADDR, 1);
int error = 0;
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ip::endpoint ep(INADDR_LOOPBACK, 0);
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error = acceptor.bind(ep);
ep = acceptor.local_endpoint();
// Some broken firewalls on Windows will intermittently cause getsockname to
// return 0.0.0.0 when the socket is actually bound to 127.0.0.1. We
// explicitly specify the target address here to work around this problem.
if (INADDR_ANY == ep.addr_v4())
ep.addr_v4(INADDR_LOOPBACK);
error = acceptor.listen();
xxsocket client(AF_INET, SOCK_STREAM, IPPROTO_TCP);
error = client.connect(ep);
auto server = acceptor.accept();
client.set_nonblocking(true);
client.set_optval(IPPROTO_TCP, TCP_NODELAY, 1);
server.set_nonblocking(true);
server.set_optval(IPPROTO_TCP, TCP_NODELAY, 1);
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read_descriptor_ = server.release_handle();
write_descriptor_ = client.release_handle();
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}
// Close the descriptors.
inline void close_descriptors()
{
if (read_descriptor_ != invalid_socket)
::closesocket(read_descriptor_);
if (write_descriptor_ != invalid_socket)
::closesocket(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.
socket_native_type 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.
socket_native_type write_descriptor_;
};
} // namespace inet
} // namespace yasio
#endif // YASIO__SOCKET_SELECT_INTERRUPTER_HPP