137 lines
4.2 KiB
C++
137 lines
4.2 KiB
C++
//
|
|
// compose.hpp
|
|
// ~~~~~~~~~~~
|
|
//
|
|
// Copyright (c) 2003-2021 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 ASIO_COMPOSE_HPP
|
|
#define ASIO_COMPOSE_HPP
|
|
|
|
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
|
|
# pragma once
|
|
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
|
|
|
|
#include "asio/detail/config.hpp"
|
|
#include "asio/async_result.hpp"
|
|
|
|
#include "asio/detail/push_options.hpp"
|
|
|
|
namespace asio {
|
|
|
|
#if defined(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_;
|
|
* asio::mutable_buffer buffer_;
|
|
* enum { starting, reading, writing } state_;
|
|
*
|
|
* template <typename Self>
|
|
* void operator()(Self& self,
|
|
* asio::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;
|
|
* asio::async_write(socket_, buffer_,
|
|
* asio::transfer_exactly(n),
|
|
* std::move(self));
|
|
* }
|
|
* break;
|
|
* case writing:
|
|
* self.complete(error, n);
|
|
* break;
|
|
* }
|
|
* }
|
|
* };
|
|
*
|
|
* template <typename CompletionToken>
|
|
* auto async_echo(tcp::socket& socket,
|
|
* asio::mutable_buffer buffer,
|
|
* CompletionToken&& token) ->
|
|
* typename asio::async_result<
|
|
* typename std::decay<CompletionToken>::type,
|
|
* void(asio::error_code, std::size_t)>::return_type
|
|
* {
|
|
* return asio::async_compose<CompletionToken,
|
|
* void(asio::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>
|
|
ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, Signature)
|
|
async_compose(ASIO_MOVE_ARG(Implementation) implementation,
|
|
ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token,
|
|
ASIO_MOVE_ARG(IoObjectsOrExecutors)... io_objects_or_executors);
|
|
|
|
#else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
|
|
// || defined(GENERATING_DOCUMENTATION)
|
|
|
|
template <typename CompletionToken, typename Signature, typename Implementation>
|
|
ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, Signature)
|
|
async_compose(ASIO_MOVE_ARG(Implementation) implementation,
|
|
ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token);
|
|
|
|
#define ASIO_PRIVATE_ASYNC_COMPOSE_DEF(n) \
|
|
template <typename CompletionToken, typename Signature, \
|
|
typename Implementation, ASIO_VARIADIC_TPARAMS(n)> \
|
|
ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, Signature) \
|
|
async_compose(ASIO_MOVE_ARG(Implementation) implementation, \
|
|
ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token, \
|
|
ASIO_VARIADIC_MOVE_PARAMS(n));
|
|
/**/
|
|
ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_ASYNC_COMPOSE_DEF)
|
|
#undef ASIO_PRIVATE_ASYNC_COMPOSE_DEF
|
|
|
|
#endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
|
|
// || defined(GENERATING_DOCUMENTATION)
|
|
|
|
} // namespace asio
|
|
|
|
#include "asio/detail/pop_options.hpp"
|
|
|
|
#include "asio/impl/compose.hpp"
|
|
|
|
#endif // ASIO_COMPOSE_HPP
|