boost/asio/compose.hpp
// // compose.hpp // ~~~~~~~~~~~ // // Copyright (c) 2003-2022 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/associated_executor.hpp> #include <boost/asio/async_result.hpp> #include <boost/asio/detail/base_from_cancellation_state.hpp> #include <boost/asio/detail/composed_work.hpp> #include <boost/asio/detail/handler_alloc_helpers.hpp> #include <boost/asio/detail/handler_cont_helpers.hpp> #include <boost/asio/detail/handler_invoke_helpers.hpp> #include <boost/asio/detail/type_traits.hpp> #include <boost/asio/detail/variadic_templates.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { namespace detail { #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) template <typename Impl, typename Work, typename Handler, typename Signature> class composed_op; template <typename Impl, typename Work, typename Handler, typename R, typename... Args> class composed_op<Impl, Work, Handler, R(Args...)> #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) template <typename Impl, typename Work, typename Handler, typename Signature> class composed_op #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) : public base_from_cancellation_state<Handler> { public: template <typename I, typename W, typename H> composed_op(BOOST_ASIO_MOVE_ARG(I) impl, BOOST_ASIO_MOVE_ARG(W) work, BOOST_ASIO_MOVE_ARG(H) handler) : base_from_cancellation_state<Handler>( handler, enable_terminal_cancellation()), impl_(BOOST_ASIO_MOVE_CAST(I)(impl)), work_(BOOST_ASIO_MOVE_CAST(W)(work)), handler_(BOOST_ASIO_MOVE_CAST(H)(handler)), invocations_(0) { } #if defined(BOOST_ASIO_HAS_MOVE) composed_op(composed_op&& other) : base_from_cancellation_state<Handler>( BOOST_ASIO_MOVE_CAST(base_from_cancellation_state< Handler>)(other)), impl_(BOOST_ASIO_MOVE_CAST(Impl)(other.impl_)), work_(BOOST_ASIO_MOVE_CAST(Work)(other.work_)), handler_(BOOST_ASIO_MOVE_CAST(Handler)(other.handler_)), invocations_(other.invocations_) { } #endif // defined(BOOST_ASIO_HAS_MOVE) typedef typename composed_work_guard< typename Work::head_type>::executor_type io_executor_type; io_executor_type get_io_executor() const BOOST_ASIO_NOEXCEPT { return work_.head_.get_executor(); } typedef typename associated_executor<Handler, io_executor_type>::type executor_type; executor_type get_executor() const BOOST_ASIO_NOEXCEPT { return (get_associated_executor)(handler_, work_.head_.get_executor()); } typedef typename associated_allocator<Handler, std::allocator<void> >::type allocator_type; allocator_type get_allocator() const BOOST_ASIO_NOEXCEPT { return (get_associated_allocator)(handler_, std::allocator<void>()); } #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) template<typename... T> void operator()(BOOST_ASIO_MOVE_ARG(T)... t) { if (invocations_ < ~0u) ++invocations_; this->get_cancellation_state().slot().clear(); impl_(*this, BOOST_ASIO_MOVE_CAST(T)(t)...); } void complete(Args... args) { this->work_.reset(); BOOST_ASIO_MOVE_OR_LVALUE(Handler)(this->handler_)( BOOST_ASIO_MOVE_CAST(Args)(args)...); } #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) void operator()() { if (invocations_ < ~0u) ++invocations_; this->get_cancellation_state().slot().clear(); impl_(*this); } void complete() { this->work_.reset(); BOOST_ASIO_MOVE_OR_LVALUE(Handler)(this->handler_)(); } #define BOOST_ASIO_PRIVATE_COMPOSED_OP_DEF(n) \ template<BOOST_ASIO_VARIADIC_TPARAMS(n)> \ void operator()(BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) \ { \ if (invocations_ < ~0u) \ ++invocations_; \ this->get_cancellation_state().slot().clear(); \ impl_(*this, BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \ } \ \ template<BOOST_ASIO_VARIADIC_TPARAMS(n)> \ void complete(BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) \ { \ this->work_.reset(); \ BOOST_ASIO_MOVE_OR_LVALUE(Handler)(this->handler_)( \ BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \ } \ /**/ BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_COMPOSED_OP_DEF) #undef BOOST_ASIO_PRIVATE_COMPOSED_OP_DEF #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) void reset_cancellation_state() { base_from_cancellation_state<Handler>::reset_cancellation_state(handler_); } template <typename Filter> void reset_cancellation_state(BOOST_ASIO_MOVE_ARG(Filter) filter) { base_from_cancellation_state<Handler>::reset_cancellation_state(handler_, BOOST_ASIO_MOVE_CAST(Filter)(filter)); } template <typename InFilter, typename OutFilter> void reset_cancellation_state(BOOST_ASIO_MOVE_ARG(InFilter) in_filter, BOOST_ASIO_MOVE_ARG(OutFilter) out_filter) { base_from_cancellation_state<Handler>::reset_cancellation_state(handler_, BOOST_ASIO_MOVE_CAST(InFilter)(in_filter), BOOST_ASIO_MOVE_CAST(OutFilter)(out_filter)); } cancellation_type_t cancelled() const BOOST_ASIO_NOEXCEPT { return base_from_cancellation_state<Handler>::cancelled(); } //private: Impl impl_; Work work_; Handler handler_; unsigned invocations_; }; template <typename Impl, typename Work, typename Handler, typename Signature> inline asio_handler_allocate_is_deprecated asio_handler_allocate(std::size_t size, composed_op<Impl, Work, Handler, Signature>* this_handler) { #if defined(BOOST_ASIO_NO_DEPRECATED) boost_asio_handler_alloc_helpers::allocate(size, this_handler->handler_); return asio_handler_allocate_is_no_longer_used(); #else // defined(BOOST_ASIO_NO_DEPRECATED) return boost_asio_handler_alloc_helpers::allocate( size, this_handler->handler_); #endif // defined(BOOST_ASIO_NO_DEPRECATED) } template <typename Impl, typename Work, typename Handler, typename Signature> inline asio_handler_deallocate_is_deprecated asio_handler_deallocate(void* pointer, std::size_t size, composed_op<Impl, Work, Handler, Signature>* this_handler) { boost_asio_handler_alloc_helpers::deallocate( pointer, size, this_handler->handler_); #if defined(BOOST_ASIO_NO_DEPRECATED) return asio_handler_deallocate_is_no_longer_used(); #endif // defined(BOOST_ASIO_NO_DEPRECATED) } template <typename Impl, typename Work, typename Handler, typename Signature> inline bool asio_handler_is_continuation( composed_op<Impl, Work, Handler, Signature>* this_handler) { return this_handler->invocations_ > 1 ? true : boost_asio_handler_cont_helpers::is_continuation( this_handler->handler_); } template <typename Function, typename Impl, typename Work, typename Handler, typename Signature> inline asio_handler_invoke_is_deprecated asio_handler_invoke(Function& function, composed_op<Impl, Work, Handler, Signature>* this_handler) { boost_asio_handler_invoke_helpers::invoke( function, this_handler->handler_); #if defined(BOOST_ASIO_NO_DEPRECATED) return asio_handler_invoke_is_no_longer_used(); #endif // defined(BOOST_ASIO_NO_DEPRECATED) } template <typename Function, typename Impl, typename Work, typename Handler, typename Signature> inline asio_handler_invoke_is_deprecated asio_handler_invoke(const Function& function, composed_op<Impl, Work, Handler, Signature>* this_handler) { boost_asio_handler_invoke_helpers::invoke( function, this_handler->handler_); #if defined(BOOST_ASIO_NO_DEPRECATED) return asio_handler_invoke_is_no_longer_used(); #endif // defined(BOOST_ASIO_NO_DEPRECATED) } template <typename Signature, typename Executors> class initiate_composed_op { public: typedef typename composed_io_executors<Executors>::head_type executor_type; template <typename T> explicit initiate_composed_op(int, BOOST_ASIO_MOVE_ARG(T) executors) : executors_(BOOST_ASIO_MOVE_CAST(T)(executors)) { } executor_type get_executor() const BOOST_ASIO_NOEXCEPT { return executors_.head_; } template <typename Handler, typename Impl> void operator()(BOOST_ASIO_MOVE_ARG(Handler) handler, BOOST_ASIO_MOVE_ARG(Impl) impl) const { composed_op<typename decay<Impl>::type, composed_work<Executors>, typename decay<Handler>::type, Signature>( BOOST_ASIO_MOVE_CAST(Impl)(impl), composed_work<Executors>(executors_), BOOST_ASIO_MOVE_CAST(Handler)(handler))(); } private: composed_io_executors<Executors> executors_; }; template <typename Signature, typename Executors> inline initiate_composed_op<Signature, Executors> make_initiate_composed_op( BOOST_ASIO_MOVE_ARG(composed_io_executors<Executors>) executors) { return initiate_composed_op<Signature, Executors>(0, BOOST_ASIO_MOVE_CAST(composed_io_executors<Executors>)(executors)); } } // namespace detail #if !defined(GENERATING_DOCUMENTATION) template <template <typename, typename> class Associator, typename Impl, typename Work, typename Handler, typename Signature, typename DefaultCandidate> struct associator<Associator, detail::composed_op<Impl, Work, Handler, Signature>, DefaultCandidate> : Associator<Handler, DefaultCandidate> { static typename Associator<Handler, DefaultCandidate>::type get(const detail::composed_op<Impl, Work, Handler, Signature>& h) BOOST_ASIO_NOEXCEPT { return Associator<Handler, DefaultCandidate>::get(h.handler_); } static BOOST_ASIO_AUTO_RETURN_TYPE_PREFIX2( typename Associator<Handler, DefaultCandidate>::type) get(const detail::composed_op<Impl, Work, Handler, Signature>& h, const DefaultCandidate& c) BOOST_ASIO_NOEXCEPT BOOST_ASIO_AUTO_RETURN_TYPE_SUFFIX(( Associator<Handler, DefaultCandidate>::get(h.handler_, c))) { return Associator<Handler, DefaultCandidate>::get(h.handler_, c); } }; #endif // !defined(GENERATING_DOCUMENTATION) #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) -> * decltype( * boost::asio::async_compose<CompletionToken, * void(boost::system::error_code, std::size_t)>( * std::declval<async_echo_implementation>(), * token, socket)) * { * 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_PREFIX(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) BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_SUFFIX(( async_initiate<CompletionToken, Signature>( detail::make_initiate_composed_op<Signature>( detail::make_composed_io_executors( detail::get_composed_io_executor( BOOST_ASIO_MOVE_CAST(IoObjectsOrExecutors)( io_objects_or_executors))...)), token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)))) { return async_initiate<CompletionToken, Signature>( detail::make_initiate_composed_op<Signature>( detail::make_composed_io_executors( detail::get_composed_io_executor( BOOST_ASIO_MOVE_CAST(IoObjectsOrExecutors)( io_objects_or_executors))...)), token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)); } #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) // || defined(GENERATING_DOCUMENTATION) template <typename CompletionToken, typename Signature, typename Implementation> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_PREFIX(CompletionToken, Signature) async_compose(BOOST_ASIO_MOVE_ARG(Implementation) implementation, BOOST_ASIO_NONDEDUCED_MOVE_ARG(CompletionToken) token) BOOST_ASIO_INITFN_AUTO_RESULT_TYPE_SUFFIX(( async_initiate<CompletionToken, Signature>( detail::make_initiate_composed_op<Signature>( detail::make_composed_io_executors()), token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)))) { return async_initiate<CompletionToken, Signature>( detail::make_initiate_composed_op<Signature>( detail::make_composed_io_executors()), token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)); } # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n) \ BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_##n # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_1 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_2 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_3 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_4 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_5 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_6 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T6)(x6)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_7 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T6)(x6)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T7)(x7)) # define BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_8 \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T1)(x1)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T2)(x2)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T3)(x3)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T4)(x4)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T5)(x5)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T6)(x6)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T7)(x7)), \ detail::get_composed_io_executor(BOOST_ASIO_MOVE_CAST(T8)(x8)) #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_PREFIX(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_INITFN_AUTO_RESULT_TYPE_SUFFIX(( \ async_initiate<CompletionToken, Signature>( \ detail::make_initiate_composed_op<Signature>( \ detail::make_composed_io_executors( \ BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n))), \ token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)))) \ { \ return async_initiate<CompletionToken, Signature>( \ detail::make_initiate_composed_op<Signature>( \ detail::make_composed_io_executors( \ BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR(n))), \ token, BOOST_ASIO_MOVE_CAST(Implementation)(implementation)); \ } \ /**/ BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF) #undef BOOST_ASIO_PRIVATE_ASYNC_COMPOSE_DEF #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_1 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_2 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_3 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_4 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_5 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_6 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_7 #undef BOOST_ASIO_PRIVATE_GET_COMPOSED_IO_EXECUTOR_8 #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) // || defined(GENERATING_DOCUMENTATION) } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_COMPOSE_HPP