139 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
		
		
			
		
	
	
			139 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
|   | //
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|  | // compose.hpp
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|  | // ~~~~~~~~~~~
 | ||
|  | //
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|  | // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
 | ||
|  | //
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|  | // 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)
 | ||
|  | //
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|  | 
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|  | #ifndef BOOST_ASIO_COMPOSE_HPP
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|  | #define BOOST_ASIO_COMPOSE_HPP
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|  | 
 | ||
|  | #if defined(_MSC_VER) && (_MSC_VER >= 1200)
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|  | # pragma once
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|  | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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|  | 
 | ||
|  | #include <boost/asio/detail/config.hpp>
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|  | #include <boost/asio/async_result.hpp>
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|  | 
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|  | #include <boost/asio/detail/push_options.hpp>
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|  | 
 | ||
|  | namespace boost { | ||
|  | namespace asio { | ||
|  | 
 | ||
|  | #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) \
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|  |   || 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_AUTO_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_AUTO_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_AUTO_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
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|  | 
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|  | #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
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|  |        //   || defined(GENERATING_DOCUMENTATION)
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|  | 
 | ||
|  | } // namespace asio
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|  | } // namespace boost
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|  | 
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|  | #include <boost/asio/detail/pop_options.hpp>
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|  | 
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|  | #include <boost/asio/impl/compose.hpp>
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|  | 
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|  | #endif // BOOST_ASIO_COMPOSE_HPP
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