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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include <asio.hpp>
#include <system_error>
#include <utility>
#include "mongo/util/assert_util.h"
namespace mongo {
namespace executor {
void logCloseFailed(std::error_code ec);
template <typename ASIOStream>
void destroyStream(ASIOStream* stream, bool connected) {
if (!connected) {
return;
}
std::error_code ec;
stream->shutdown(asio::ip::tcp::socket::shutdown_both, ec);
if (ec) {
logCloseFailed(ec);
}
stream->close(ec);
if (ec) {
logCloseFailed(ec);
}
}
template <typename ASIOStream, typename Buffer, typename Handler>
void writeStream(ASIOStream* stream,
asio::io_service::strand* strand,
bool connected,
Buffer&& buffer,
Handler&& handler) {
invariant(connected);
asio::async_write(*stream,
asio::buffer(std::forward<Buffer>(buffer)),
strand->wrap(std::forward<Handler>(handler)));
}
template <typename ASIOStream, typename Buffer, typename Handler>
void readStream(ASIOStream* stream,
asio::io_service::strand* strand,
bool connected,
Buffer&& buffer,
Handler&& handler) {
invariant(connected);
asio::async_read(*stream,
asio::buffer(std::forward<Buffer>(buffer)),
strand->wrap(std::forward<Handler>(handler)));
}
template <typename ASIOStream>
void cancelStream(ASIOStream* stream, bool connected) {
stream->cancel();
}
void logFailureInSetStreamNonBlocking(std::error_code ec);
void logFailureInSetStreamNoDelay(std::error_code ec);
template <typename ASIOStream>
std::error_code setStreamNonBlocking(ASIOStream* stream) {
std::error_code ec;
stream->non_blocking(true, ec);
if (ec) {
logFailureInSetStreamNonBlocking(ec);
}
return ec;
}
template <typename ASIOStream>
std::error_code setStreamNoDelay(ASIOStream* stream) {
std::error_code ec;
stream->set_option(asio::ip::tcp::no_delay(true), ec);
if (ec) {
logFailureInSetStreamNoDelay(ec);
}
return ec;
}
void logUnexpectedErrorInCheckOpen(std::error_code ec);
template <typename ASIOStream>
bool checkIfStreamIsOpen(ASIOStream* stream, bool connected) {
if (!connected) {
return false;
};
std::error_code ec;
std::array<char, 1> buf;
// Although we call the blocking form of receive, we ensure the socket is in non-blocking mode.
// ASIO implements receive on POSIX using the 'recvmsg' system call, which returns immediately
// if the socket is non-blocking and in a valid state, but there is no data to receive. On
// windows, receive is implemented with WSARecv, which has the same semantics.
invariant(stream->non_blocking());
stream->receive(asio::buffer(buf), asio::socket_base::message_peek, ec);
if (!ec || ec == asio::error::would_block || ec == asio::error::try_again) {
// If the read worked or we got EWOULDBLOCK or EAGAIN (since we are in non-blocking mode),
// we assume the socket is still open.
return true;
} else if (ec == asio::error::eof) {
return false;
}
// We got a different error. Log it and return false so we throw the connection away.
logUnexpectedErrorInCheckOpen(ec);
return false;
}
} // namespace executor
} // namespace mongo
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