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Diffstat (limited to 'boost/asio/compose.hpp')
-rw-r--r-- | boost/asio/compose.hpp | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/boost/asio/compose.hpp b/boost/asio/compose.hpp new file mode 100644 index 0000000000..b38e4faecb --- /dev/null +++ b/boost/asio/compose.hpp @@ -0,0 +1,138 @@ +// +// compose.hpp +// ~~~~~~~~~~~ +// +// Copyright (c) 2003-2019 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) +// + +#ifndef BOOST_ASIO_COMPOSE_HPP +#define BOOST_ASIO_COMPOSE_HPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include <boost/asio/detail/config.hpp> +#include <boost/asio/async_result.hpp> + +#include <boost/asio/detail/push_options.hpp> + +namespace boost { +namespace asio { + +#if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) \ + || defined(GENERATING_DOCUMENTATION) + +/// Launch an asynchronous operation with a stateful implementation. +/** + * The async_compose function simplifies the implementation of composed + * asynchronous operations automatically wrapping a stateful function object + * with a conforming intermediate completion handler. + * + * @param implementation A function object that contains the implementation of + * the composed asynchronous operation. The first argument to the function + * object is a non-const reference to the enclosing intermediate completion + * handler. The remaining arguments are any arguments that originate from the + * completion handlers of any asynchronous operations performed by the + * implementation. + + * @param token The completion token. + * + * @param io_objects_or_executors Zero or more I/O objects or I/O executors for + * which outstanding work must be maintained. + * + * @par Example: + * + * @code struct async_echo_implementation + * { + * tcp::socket& socket_; + * boost::asio::mutable_buffer buffer_; + * enum { starting, reading, writing } state_; + * + * template <typename Self> + * void operator()(Self& self, + * boost::system::error_code error = {}, + * std::size_t n = 0) + * { + * switch (state_) + * { + * case starting: + * state_ = reading; + * socket_.async_read_some( + * buffer_, std::move(self)); + * break; + * case reading: + * if (error) + * { + * self.complete(error, 0); + * } + * else + * { + * state_ = writing; + * boost::asio::async_write(socket_, buffer_, + * boost::asio::transfer_exactly(n), + * std::move(self)); + * } + * break; + * case writing: + * self.complete(error, n); + * break; + * } + * } + * }; + * + * template <typename CompletionToken> + * auto async_echo(tcp::socket& socket, + * boost::asio::mutable_buffer buffer, + * CompletionToken&& token) -> + * typename boost::asio::async_result< + * typename std::decay<CompletionToken>::type, + * void(boost::system::error_code, std::size_t)>::return_type + * { + * return boost::asio::async_compose<CompletionToken, + * void(boost::system::error_code, std::size_t)>( + * async_echo_implementation{socket, buffer, + * async_echo_implementation::starting}, + * token, socket); + * } @endcode + */ +template <typename CompletionToken, typename Signature, + typename Implementation, typename... IoObjectsOrExecutors> +BOOST_ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature) +async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation, + BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token, + BOOST_ASIO_MOVE_ARG(IoObjectsOrExecutors)... io_objects_or_executors); + +#else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) + // || defined(GENERATING_DOCUMENTATION) + +template <typename CompletionToken, typename Signature, typename Implementation> +BOOST_ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature) +async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation, + BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token); + +#define BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF(n) \ + template <typename CompletionToken, typename Signature, \ + typename Implementation, BOOST_ASIO_VARIADIC_TPARAMS(n)> \ + BOOST_ASIO_INITFN_RESULT_TYPE(CompletionToken, Signature) \ + async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation, \ + BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token, \ + BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)); + /**/ + BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF) +#undef BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF + +#endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) + // || defined(GENERATING_DOCUMENTATION) + +} // namespace asio +} // namespace boost + +#include <boost/asio/detail/pop_options.hpp> + +#include <boost/asio/impl/compose.hpp> + +#endif // BOOST_ASIO_COMPOSE_HPP |