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/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file os_abstraction.cpp OS specific implementations of functions of the OS abstraction layer for network stuff.
*
* The general idea is to have simple abstracting functions for things that
* require different implementations for different environments.
* In here the functions, and their documentation, are defined only once
* and the implementation contains the #ifdefs to change the implementation.
* Since Windows is usually different that is usually the first case, after
* that the behaviour is usually Unix/BSD-like with occasional variation.
*/
#include "stdafx.h"
#include "os_abstraction.h"
#include "../../string_func.h"
#include <mutex>
#include "../../safeguards.h"
/**
* Construct the network error with the given error code.
* @param error The error code.
*/
NetworkError::NetworkError(int error) : error(error)
{
}
/**
* Check whether this error describes that the operation would block.
* @return True iff the operation would block.
*/
bool NetworkError::WouldBlock() const
{
#if defined(_WIN32)
return this->error == WSAEWOULDBLOCK;
#else
/* Usually EWOULDBLOCK and EAGAIN are the same, but sometimes they are not
* and the POSIX.1 specification states that either should be checked. */
return this->error == EWOULDBLOCK || this->error == EAGAIN;
#endif
}
/**
* Check whether this error describes a connection reset.
* @return True iff the connection is reset.
*/
bool NetworkError::IsConnectionReset() const
{
#if defined(_WIN32)
return this->error == WSAECONNRESET;
#else
return this->error == ECONNRESET;
#endif
}
/**
* Check whether this error describes a connect is in progress.
* @return True iff the connect is already in progress.
*/
bool NetworkError::IsConnectInProgress() const
{
#if defined(_WIN32)
return this->error == WSAEWOULDBLOCK;
#else
return this->error == EINPROGRESS;
#endif
}
/**
* Get the string representation of the error message.
* @return The string representation that will get overwritten by next calls.
*/
const char *NetworkError::AsString() const
{
if (this->message.empty()) {
#if defined(_WIN32)
char buffer[512];
if (FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, this->error,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), buffer, sizeof(buffer), NULL) == 0) {
seprintf(buffer, lastof(buffer), "Unknown error %d", this->error);
}
this->message.assign(buffer);
#else
/* Make strerror thread safe by locking access to it. There is a thread safe strerror_r, however
* the non-POSIX variant is available due to defining _GNU_SOURCE meaning it is not portable.
* The problem with the non-POSIX variant is that it does not necessarily fill the buffer with
* the error message but can also return a pointer to a static bit of memory, whereas the POSIX
* variant always fills the buffer. This makes the behaviour too erratic to work with. */
static std::mutex mutex;
std::lock_guard<std::mutex> guard(mutex);
this->message.assign(strerror(this->error));
#endif
}
return this->message.c_str();
}
/**
* Check whether an error was actually set.
* @return True iff an error was set.
*/
bool NetworkError::HasError() const
{
return this->error != 0;
}
/**
* Get the last network error.
* @return The network error.
*/
/* static */ NetworkError NetworkError::GetLast()
{
#if defined(_WIN32)
return NetworkError(WSAGetLastError());
#elif defined(__OS2__)
return NetworkError(sock_errno());
#else
return NetworkError(errno);
#endif
}
/**
* Try to set the socket into non-blocking mode.
* @param d The socket to set the non-blocking more for.
* @return True if setting the non-blocking mode succeeded, otherwise false.
*/
bool SetNonBlocking(SOCKET d)
{
#if defined(_WIN32)
u_long nonblocking = 1;
return ioctlsocket(d, FIONBIO, &nonblocking) == 0;
#elif defined __EMSCRIPTEN__
return true;
#else
int nonblocking = 1;
return ioctl(d, FIONBIO, &nonblocking) == 0;
#endif
}
/**
* Try to set the socket to not delay sending.
* @param d The socket to disable the delaying for.
* @return True if disabling the delaying succeeded, otherwise false.
*/
bool SetNoDelay(SOCKET d)
{
#ifdef __EMSCRIPTEN__
return true;
#else
int flags = 1;
/* The (const char*) cast is needed for windows */
return setsockopt(d, IPPROTO_TCP, TCP_NODELAY, (const char *)&flags, sizeof(flags)) == 0;
#endif
}
/**
* Get the error from a socket, if any.
* @param d The socket to get the error from.
* @return The errno on the socket.
*/
NetworkError GetSocketError(SOCKET d)
{
int err;
socklen_t len = sizeof(err);
getsockopt(d, SOL_SOCKET, SO_ERROR, (char *)&err, &len);
return NetworkError(err);
}
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