291 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			C++
		
	
	
	
		
		
			
		
	
	
			291 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			C++
		
	
	
	
|  | //
 | ||
|  | // execution/execute.hpp
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|  | // ~~~~~~~~~~~~~~~~~~~~~
 | ||
|  | //
 | ||
|  | // Copyright (c) 2003-2023 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)
 | ||
|  | //
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|  | 
 | ||
|  | #ifndef ASIO_EXECUTION_EXECUTE_HPP
 | ||
|  | #define ASIO_EXECUTION_EXECUTE_HPP
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|  | 
 | ||
|  | #if defined(_MSC_VER) && (_MSC_VER >= 1200)
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|  | # pragma once
 | ||
|  | #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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|  | 
 | ||
|  | #include "asio/detail/config.hpp"
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|  | 
 | ||
|  | #if !defined(ASIO_NO_DEPRECATED)
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|  | 
 | ||
|  | #include "asio/detail/type_traits.hpp"
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|  | #include "asio/execution/detail/as_invocable.hpp"
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|  | #include "asio/execution/detail/as_receiver.hpp"
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|  | #include "asio/traits/execute_member.hpp"
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|  | #include "asio/traits/execute_free.hpp"
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|  | 
 | ||
|  | #include "asio/detail/push_options.hpp"
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|  | 
 | ||
|  | #if defined(GENERATING_DOCUMENTATION)
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|  | 
 | ||
|  | namespace asio { | ||
|  | namespace execution { | ||
|  | 
 | ||
|  | /// (Deprecated: Use @c execute member function.) A customisation point that
 | ||
|  | /// executes a function on an executor.
 | ||
|  | /**
 | ||
|  |  * The name <tt>execution::execute</tt> denotes a customisation point object. | ||
|  |  * | ||
|  |  * For some subexpressions <tt>e</tt> and <tt>f</tt>, let <tt>E</tt> be a type | ||
|  |  * such that <tt>decltype((e))</tt> is <tt>E</tt> and let <tt>F</tt> be a type | ||
|  |  * such that <tt>decltype((f))</tt> is <tt>F</tt>. The expression | ||
|  |  * <tt>execution::execute(e, f)</tt> is ill-formed if <tt>F</tt> does not model | ||
|  |  * <tt>invocable</tt>, or if <tt>E</tt> does not model either <tt>executor</tt> | ||
|  |  * or <tt>sender</tt>. Otherwise, it is expression-equivalent to: | ||
|  |  * | ||
|  |  * @li <tt>e.execute(f)</tt>, if that expression is valid. If the function | ||
|  |  *   selected does not execute the function object <tt>f</tt> on the executor | ||
|  |  *   <tt>e</tt>, the program is ill-formed with no diagnostic required. | ||
|  |  * | ||
|  |  * @li Otherwise, <tt>execute(e, f)</tt>, if that expression is valid, with | ||
|  |  *   overload resolution performed in a context that includes the declaration | ||
|  |  *   <tt>void execute();</tt> and that does not include a declaration of | ||
|  |  *   <tt>execution::execute</tt>. If the function selected by overload | ||
|  |  *   resolution does not execute the function object <tt>f</tt> on the executor | ||
|  |  *   <tt>e</tt>, the program is ill-formed with no diagnostic required. | ||
|  |  */ | ||
|  | inline constexpr unspecified execute = unspecified; | ||
|  | 
 | ||
|  | /// (Deprecated.) A type trait that determines whether an @c execute expression
 | ||
|  | /// is well-formed.
 | ||
|  | /**
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|  |  * Class template @c can_execute is a trait that is derived from | ||
|  |  * @c true_type if the expression <tt>execution::execute(std::declval<T>(), | ||
|  |  * std::declval<F>())</tt> is well formed; otherwise @c false_type. | ||
|  |  */ | ||
|  | template <typename T, typename F> | ||
|  | struct can_execute : | ||
|  |   integral_constant<bool, automatically_determined> | ||
|  | { | ||
|  | }; | ||
|  | 
 | ||
|  | } // namespace execution
 | ||
|  | } // namespace asio
 | ||
|  | 
 | ||
|  | #else // defined(GENERATING_DOCUMENTATION)
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|  | 
 | ||
|  | namespace asio { | ||
|  | namespace execution { | ||
|  | 
 | ||
|  | template <typename T, typename R> | ||
|  | struct is_sender_to; | ||
|  | 
 | ||
|  | namespace detail { | ||
|  | 
 | ||
|  | template <typename S, typename R> | ||
|  | void submit_helper(ASIO_MOVE_ARG(S) s, ASIO_MOVE_ARG(R) r); | ||
|  | 
 | ||
|  | } // namespace detail
 | ||
|  | } // namespace execution
 | ||
|  | } // namespace asio
 | ||
|  | namespace asio_execution_execute_fn { | ||
|  | 
 | ||
|  | using asio::conditional; | ||
|  | using asio::decay; | ||
|  | using asio::declval; | ||
|  | using asio::enable_if; | ||
|  | using asio::execution::detail::as_receiver; | ||
|  | using asio::execution::detail::is_as_invocable; | ||
|  | using asio::execution::is_sender_to; | ||
|  | using asio::false_type; | ||
|  | using asio::result_of; | ||
|  | using asio::traits::execute_free; | ||
|  | using asio::traits::execute_member; | ||
|  | using asio::true_type; | ||
|  | using asio::void_type; | ||
|  | 
 | ||
|  | void execute(); | ||
|  | 
 | ||
|  | enum overload_type | ||
|  | { | ||
|  |   call_member, | ||
|  |   call_free, | ||
|  |   adapter, | ||
|  |   ill_formed | ||
|  | }; | ||
|  | 
 | ||
|  | template <typename Impl, typename T, typename F, typename = void, | ||
|  |     typename = void, typename = void, typename = void, typename = void> | ||
|  | struct call_traits | ||
|  | { | ||
|  |   ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed); | ||
|  | }; | ||
|  | 
 | ||
|  | template <typename Impl, typename T, typename F> | ||
|  | struct call_traits<Impl, T, void(F), | ||
|  |   typename enable_if< | ||
|  |     execute_member<typename Impl::template proxy<T>::type, F>::is_valid | ||
|  |   >::type> : | ||
|  |   execute_member<typename Impl::template proxy<T>::type, F> | ||
|  | { | ||
|  |   ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member); | ||
|  | }; | ||
|  | 
 | ||
|  | template <typename Impl, typename T, typename F> | ||
|  | struct call_traits<Impl, T, void(F), | ||
|  |   typename enable_if< | ||
|  |     !execute_member<typename Impl::template proxy<T>, F>::is_valid | ||
|  |   >::type, | ||
|  |   typename enable_if< | ||
|  |     execute_free<T, F>::is_valid | ||
|  |   >::type> : | ||
|  |   execute_free<T, F> | ||
|  | { | ||
|  |   ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free); | ||
|  | }; | ||
|  | 
 | ||
|  | template <typename Impl, typename T, typename F> | ||
|  | struct call_traits<Impl, T, void(F), | ||
|  |   typename enable_if< | ||
|  |     !execute_member<typename Impl::template proxy<T>::type, F>::is_valid | ||
|  |   >::type, | ||
|  |   typename enable_if< | ||
|  |     !execute_free<T, F>::is_valid | ||
|  |   >::type, | ||
|  |   typename void_type< | ||
|  |    typename result_of<typename decay<F>::type&()>::type | ||
|  |   >::type, | ||
|  |   typename enable_if< | ||
|  |     !is_as_invocable<typename decay<F>::type>::value | ||
|  |   >::type, | ||
|  |   typename enable_if< | ||
|  |     is_sender_to<T, as_receiver<typename decay<F>::type, T> >::value | ||
|  |   >::type> | ||
|  | { | ||
|  |   ASIO_STATIC_CONSTEXPR(overload_type, overload = adapter); | ||
|  |   ASIO_STATIC_CONSTEXPR(bool, is_valid = true); | ||
|  |   ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false); | ||
|  |   typedef void result_type; | ||
|  | }; | ||
|  | 
 | ||
|  | struct impl | ||
|  | { | ||
|  |   template <typename T> | ||
|  |   struct proxy | ||
|  |   { | ||
|  | #if defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT)
 | ||
|  |     struct type | ||
|  |     { | ||
|  |       template <typename F> | ||
|  |       auto execute(ASIO_MOVE_ARG(F) f) | ||
|  |         noexcept( | ||
|  |           noexcept( | ||
|  |             declval<typename conditional<true, T, F>::type>().execute( | ||
|  |               ASIO_MOVE_CAST(F)(f)) | ||
|  |           ) | ||
|  |         ) | ||
|  |         -> decltype( | ||
|  |           declval<typename conditional<true, T, F>::type>().execute( | ||
|  |             ASIO_MOVE_CAST(F)(f)) | ||
|  |         ); | ||
|  |     }; | ||
|  | #else // defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT)
 | ||
|  |     typedef T type; | ||
|  | #endif // defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT)
 | ||
|  |   }; | ||
|  | 
 | ||
|  |   template <typename T, typename F> | ||
|  |   ASIO_CONSTEXPR typename enable_if< | ||
|  |     call_traits<impl, T, void(F)>::overload == call_member, | ||
|  |     typename call_traits<impl, T, void(F)>::result_type | ||
|  |   >::type | ||
|  |   operator()( | ||
|  |       ASIO_MOVE_ARG(T) t, | ||
|  |       ASIO_MOVE_ARG(F) f) const | ||
|  |     ASIO_NOEXCEPT_IF(( | ||
|  |       call_traits<impl, T, void(F)>::is_noexcept)) | ||
|  |   { | ||
|  |     return ASIO_MOVE_CAST(T)(t).execute(ASIO_MOVE_CAST(F)(f)); | ||
|  |   } | ||
|  | 
 | ||
|  |   template <typename T, typename F> | ||
|  |   ASIO_CONSTEXPR typename enable_if< | ||
|  |     call_traits<impl, T, void(F)>::overload == call_free, | ||
|  |     typename call_traits<impl, T, void(F)>::result_type | ||
|  |   >::type | ||
|  |   operator()( | ||
|  |       ASIO_MOVE_ARG(T) t, | ||
|  |       ASIO_MOVE_ARG(F) f) const | ||
|  |     ASIO_NOEXCEPT_IF(( | ||
|  |       call_traits<impl, T, void(F)>::is_noexcept)) | ||
|  |   { | ||
|  |     return execute(ASIO_MOVE_CAST(T)(t), ASIO_MOVE_CAST(F)(f)); | ||
|  |   } | ||
|  | 
 | ||
|  |   template <typename T, typename F> | ||
|  |   ASIO_CONSTEXPR typename enable_if< | ||
|  |     call_traits<impl, T, void(F)>::overload == adapter, | ||
|  |     typename call_traits<impl, T, void(F)>::result_type | ||
|  |   >::type | ||
|  |   operator()( | ||
|  |       ASIO_MOVE_ARG(T) t, | ||
|  |       ASIO_MOVE_ARG(F) f) const | ||
|  |     ASIO_NOEXCEPT_IF(( | ||
|  |       call_traits<impl, T, void(F)>::is_noexcept)) | ||
|  |   { | ||
|  |     return asio::execution::detail::submit_helper( | ||
|  |         ASIO_MOVE_CAST(T)(t), | ||
|  |         as_receiver<typename decay<F>::type, T>( | ||
|  |           ASIO_MOVE_CAST(F)(f), 0)); | ||
|  |   } | ||
|  | }; | ||
|  | 
 | ||
|  | template <typename T = impl> | ||
|  | struct static_instance | ||
|  | { | ||
|  |   static const T instance; | ||
|  | }; | ||
|  | 
 | ||
|  | template <typename T> | ||
|  | const T static_instance<T>::instance = {}; | ||
|  | 
 | ||
|  | } // namespace asio_execution_execute_fn
 | ||
|  | namespace asio { | ||
|  | namespace execution { | ||
|  | namespace { | ||
|  | 
 | ||
|  | static ASIO_CONSTEXPR const asio_execution_execute_fn::impl& | ||
|  |   execute = asio_execution_execute_fn::static_instance<>::instance; | ||
|  | 
 | ||
|  | } // namespace
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|  | 
 | ||
|  | typedef asio_execution_execute_fn::impl execute_t; | ||
|  | 
 | ||
|  | template <typename T, typename F> | ||
|  | struct can_execute : | ||
|  |   integral_constant<bool, | ||
|  |     asio_execution_execute_fn::call_traits< | ||
|  |       execute_t, T, void(F)>::overload != | ||
|  |         asio_execution_execute_fn::ill_formed> | ||
|  | { | ||
|  | }; | ||
|  | 
 | ||
|  | #if defined(ASIO_HAS_VARIABLE_TEMPLATES)
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|  | 
 | ||
|  | template <typename T, typename F> | ||
|  | constexpr bool can_execute_v = can_execute<T, F>::value; | ||
|  | 
 | ||
|  | #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)
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|  | 
 | ||
|  | } // namespace execution
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|  | } // namespace asio
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|  | 
 | ||
|  | #endif // defined(GENERATING_DOCUMENTATION)
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|  | 
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|  | #include "asio/detail/pop_options.hpp"
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|  | 
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|  | #endif // !defined(ASIO_NO_DEPRECATED)
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|  | 
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|  | #endif // ASIO_EXECUTION_EXECUTE_HPP
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