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Diffstat (limited to '3rdparty/asio/src/examples/cpp11/timeouts/blocking_tcp_client.cpp')
-rw-r--r-- | 3rdparty/asio/src/examples/cpp11/timeouts/blocking_tcp_client.cpp | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/3rdparty/asio/src/examples/cpp11/timeouts/blocking_tcp_client.cpp b/3rdparty/asio/src/examples/cpp11/timeouts/blocking_tcp_client.cpp new file mode 100644 index 00000000000..e29edc2895f --- /dev/null +++ b/3rdparty/asio/src/examples/cpp11/timeouts/blocking_tcp_client.cpp @@ -0,0 +1,192 @@ +// +// blocking_tcp_client.cpp +// ~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff 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) +// + +#include "asio/buffer.hpp" +#include "asio/connect.hpp" +#include "asio/io_context.hpp" +#include "asio/ip/tcp.hpp" +#include "asio/read_until.hpp" +#include "asio/system_error.hpp" +#include "asio/write.hpp" +#include <cstdlib> +#include <iostream> +#include <string> + +using asio::ip::tcp; + +//---------------------------------------------------------------------- + +// +// This class manages socket timeouts by running the io_context using the timed +// io_context::run_for() member function. Each asynchronous operation is given +// a timeout within which it must complete. The socket operations themselves +// use lambdas as completion handlers. For a given socket operation, the client +// object runs the io_context to block thread execution until the operation +// completes or the timeout is reached. If the io_context::run_for() function +// times out, the socket is closed and the outstanding asynchronous operation +// is cancelled. +// +class client +{ +public: + void connect(const std::string& host, const std::string& service, + std::chrono::steady_clock::duration timeout) + { + // Resolve the host name and service to a list of endpoints. + auto endpoints = tcp::resolver(io_context_).resolve(host, service); + + // Start the asynchronous operation itself. The lambda that is used as a + // callback will update the error variable when the operation completes. + // The blocking_udp_client.cpp example shows how you can use std::bind + // rather than a lambda. + std::error_code error; + asio::async_connect(socket_, endpoints, + [&](const std::error_code& result_error, + const tcp::endpoint& /*result_endpoint*/) + { + error = result_error; + }); + + // Run the operation until it completes, or until the timeout. + run(timeout); + + // Determine whether a connection was successfully established. + if (error) + throw std::system_error(error); + } + + std::string read_line(std::chrono::steady_clock::duration timeout) + { + // Start the asynchronous operation. The lambda that is used as a callback + // will update the error and n variables when the operation completes. The + // blocking_udp_client.cpp example shows how you can use std::bind rather + // than a lambda. + std::error_code error; + std::size_t n = 0; + asio::async_read_until(socket_, + asio::dynamic_buffer(input_buffer_), '\n', + [&](const std::error_code& result_error, + std::size_t result_n) + { + error = result_error; + n = result_n; + }); + + // Run the operation until it completes, or until the timeout. + run(timeout); + + // Determine whether the read completed successfully. + if (error) + throw std::system_error(error); + + std::string line(input_buffer_.substr(0, n - 1)); + input_buffer_.erase(0, n); + return line; + } + + void write_line(const std::string& line, + std::chrono::steady_clock::duration timeout) + { + std::string data = line + "\n"; + + // Start the asynchronous operation itself. The lambda that is used as a + // callback will update the error variable when the operation completes. + // The blocking_udp_client.cpp example shows how you can use std::bind + // rather than a lambda. + std::error_code error; + asio::async_write(socket_, asio::buffer(data), + [&](const std::error_code& result_error, + std::size_t /*result_n*/) + { + error = result_error; + }); + + // Run the operation until it completes, or until the timeout. + run(timeout); + + // Determine whether the read completed successfully. + if (error) + throw std::system_error(error); + } + +private: + void run(std::chrono::steady_clock::duration timeout) + { + // Restart the io_context, as it may have been left in the "stopped" state + // by a previous operation. + io_context_.restart(); + + // Block until the asynchronous operation has completed, or timed out. If + // the pending asynchronous operation is a composed operation, the deadline + // applies to the entire operation, rather than individual operations on + // the socket. + io_context_.run_for(timeout); + + // If the asynchronous operation completed successfully then the io_context + // would have been stopped due to running out of work. If it was not + // stopped, then the io_context::run_for call must have timed out. + if (!io_context_.stopped()) + { + // Close the socket to cancel the outstanding asynchronous operation. + socket_.close(); + + // Run the io_context again until the operation completes. + io_context_.run(); + } + } + + asio::io_context io_context_; + tcp::socket socket_{io_context_}; + std::string input_buffer_; +}; + +//---------------------------------------------------------------------- + +int main(int argc, char* argv[]) +{ + try + { + if (argc != 4) + { + std::cerr << "Usage: blocking_tcp_client <host> <port> <message>\n"; + return 1; + } + + client c; + c.connect(argv[1], argv[2], std::chrono::seconds(10)); + + auto time_sent = std::chrono::steady_clock::now(); + + c.write_line(argv[3], std::chrono::seconds(10)); + + for (;;) + { + std::string line = c.read_line(std::chrono::seconds(10)); + + // Keep going until we get back the line that was sent. + if (line == argv[3]) + break; + } + + auto time_received = std::chrono::steady_clock::now(); + + std::cout << "Round trip time: "; + std::cout << std::chrono::duration_cast< + std::chrono::microseconds>( + time_received - time_sent).count(); + std::cout << " microseconds\n"; + } + catch (std::exception& e) + { + std::cerr << "Exception: " << e.what() << "\n"; + } + + return 0; +} |