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편집 파일: system_executor.hpp

// // system_executor.hpp // ~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2024 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_SYSTEM_EXECUTOR_HPP #define BOOST_ASIO_SYSTEM_EXECUTOR_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/detail/memory.hpp> #include <boost/asio/execution.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { class system_context; /// An executor that uses arbitrary threads. /** * The system executor represents an execution context where functions are * permitted to run on arbitrary threads. When the blocking.never property is * established, the system executor will schedule the function to run on an * unspecified system thread pool. When either blocking.possibly or * blocking.always is established, the executor invokes the function * immediately. */ template <typename Blocking, typename Relationship, typename Allocator> class basic_system_executor { public: /// Default constructor. basic_system_executor() noexcept : allocator_(Allocator()) { } #if !defined(GENERATING_DOCUMENTATION) private: friend struct boost_asio_require_fn::impl; friend struct boost_asio_prefer_fn::impl; #endif // !defined(GENERATING_DOCUMENTATION) /// Obtain an executor with the @c blocking.possibly property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::blocking.possibly); @endcode */ basic_system_executor<execution::blocking_t::possibly_t, Relationship, Allocator> require(execution::blocking_t::possibly_t) const { return basic_system_executor<execution::blocking_t::possibly_t, Relationship, Allocator>(allocator_); } /// Obtain an executor with the @c blocking.always property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::blocking.always); @endcode */ basic_system_executor<execution::blocking_t::always_t, Relationship, Allocator> require(execution::blocking_t::always_t) const { return basic_system_executor<execution::blocking_t::always_t, Relationship, Allocator>(allocator_); } /// Obtain an executor with the @c blocking.never property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::blocking.never); @endcode */ basic_system_executor<execution::blocking_t::never_t, Relationship, Allocator> require(execution::blocking_t::never_t) const { return basic_system_executor<execution::blocking_t::never_t, Relationship, Allocator>(allocator_); } /// Obtain an executor with the @c relationship.continuation property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::relationship.continuation); @endcode */ basic_system_executor<Blocking, execution::relationship_t::continuation_t, Allocator> require(execution::relationship_t::continuation_t) const { return basic_system_executor<Blocking, execution::relationship_t::continuation_t, Allocator>(allocator_); } /// Obtain an executor with the @c relationship.fork property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::relationship.fork); @endcode */ basic_system_executor<Blocking, execution::relationship_t::fork_t, Allocator> require(execution::relationship_t::fork_t) const { return basic_system_executor<Blocking, execution::relationship_t::fork_t, Allocator>(allocator_); } /// Obtain an executor with the specified @c allocator property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::allocator(my_allocator)); @endcode */ template <typename OtherAllocator> basic_system_executor<Blocking, Relationship, OtherAllocator> require(execution::allocator_t<OtherAllocator> a) const { return basic_system_executor<Blocking, Relationship, OtherAllocator>(a.value()); } /// Obtain an executor with the default @c allocator property. /** * Do not call this function directly. It is intended for use with the * boost::asio::require customisation point. * * For example: * @code boost::asio::system_executor ex1; * auto ex2 = boost::asio::require(ex1, * boost::asio::execution::allocator); @endcode */ basic_system_executor<Blocking, Relationship, std::allocator<void>> require(execution::allocator_t<void>) const { return basic_system_executor<Blocking, Relationship, std::allocator<void>>(); } #if !defined(GENERATING_DOCUMENTATION) private: friend struct boost_asio_query_fn::impl; friend struct boost::asio::execution::detail::blocking_t<0>; friend struct boost::asio::execution::detail::mapping_t<0>; friend struct boost::asio::execution::detail::outstanding_work_t<0>; friend struct boost::asio::execution::detail::relationship_t<0>; #endif // !defined(GENERATING_DOCUMENTATION) /// Query the current value of the @c mapping property. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * if (boost::asio::query(ex, boost::asio::execution::mapping) * == boost::asio::execution::mapping.thread) * ... @endcode */ static constexpr execution::mapping_t query( execution::mapping_t) noexcept { return execution::mapping.thread; } /// Query the current value of the @c context property. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * boost::asio::system_context& pool = boost::asio::query( * ex, boost::asio::execution::context); @endcode */ static system_context& query(execution::context_t) noexcept; /// Query the current value of the @c blocking property. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * if (boost::asio::query(ex, boost::asio::execution::blocking) * == boost::asio::execution::blocking.always) * ... @endcode */ static constexpr execution::blocking_t query( execution::blocking_t) noexcept { return Blocking(); } /// Query the current value of the @c relationship property. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * if (boost::asio::query(ex, boost::asio::execution::relationship) * == boost::asio::execution::relationship.continuation) * ... @endcode */ static constexpr execution::relationship_t query( execution::relationship_t) noexcept { return Relationship(); } /// Query the current value of the @c allocator property. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * auto alloc = boost::asio::query(ex, * boost::asio::execution::allocator); @endcode */ template <typename OtherAllocator> constexpr Allocator query( execution::allocator_t<OtherAllocator>) const noexcept { return allocator_; } /// Query the current value of the @c allocator property. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * auto alloc = boost::asio::query(ex, * boost::asio::execution::allocator); @endcode */ constexpr Allocator query( execution::allocator_t<void>) const noexcept { return allocator_; } /// Query the occupancy (recommended number of work items) for the system /// context. /** * Do not call this function directly. It is intended for use with the * boost::asio::query customisation point. * * For example: * @code boost::asio::system_executor ex; * std::size_t occupancy = boost::asio::query( * ex, boost::asio::execution::occupancy); @endcode */ std::size_t query(execution::occupancy_t) const noexcept; public: /// Compare two executors for equality. /** * Two executors are equal if they refer to the same underlying io_context. */ friend bool operator==(const basic_system_executor&, const basic_system_executor&) noexcept { return true; } /// Compare two executors for inequality. /** * Two executors are equal if they refer to the same underlying io_context. */ friend bool operator!=(const basic_system_executor&, const basic_system_executor&) noexcept { return false; } /// Execution function. template <typename Function> void execute(Function&& f) const { this->do_execute(static_cast<Function&&>(f), Blocking()); } #if !defined(BOOST_ASIO_NO_TS_EXECUTORS) public: /// Obtain the underlying execution context. system_context& context() const noexcept; /// Inform the executor that it has some outstanding work to do. /** * For the system executor, this is a no-op. */ void on_work_started() const noexcept { } /// Inform the executor that some work is no longer outstanding. /** * For the system executor, this is a no-op. */ void on_work_finished() const noexcept { } /// Request the system executor to invoke the given function object. /** * This function is used to ask the executor to execute the given function * object. The function object will always be executed inside this function. * * @param f The function object to be called. The executor will make * a copy of the handler object as required. The function signature of the * function object must be: @code void function(); @endcode * * @param a An allocator that may be used by the executor to allocate the * internal storage needed for function invocation. */ template <typename Function, typename OtherAllocator> void dispatch(Function&& f, const OtherAllocator& a) const; /// Request the system executor to invoke the given function object. /** * This function is used to ask the executor to execute the given function * object. The function object will never be executed inside this function. * Instead, it will be scheduled to run on an unspecified system thread pool. * * @param f The function object to be called. The executor will make * a copy of the handler object as required. The function signature of the * function object must be: @code void function(); @endcode * * @param a An allocator that may be used by the executor to allocate the * internal storage needed for function invocation. */ template <typename Function, typename OtherAllocator> void post(Function&& f, const OtherAllocator& a) const; /// Request the system executor to invoke the given function object. /** * This function is used to ask the executor to execute the given function * object. The function object will never be executed inside this function. * Instead, it will be scheduled to run on an unspecified system thread pool. * * @param f The function object to be called. The executor will make * a copy of the handler object as required. The function signature of the * function object must be: @code void function(); @endcode * * @param a An allocator that may be used by the executor to allocate the * internal storage needed for function invocation. */ template <typename Function, typename OtherAllocator> void defer(Function&& f, const OtherAllocator& a) const; #endif // !defined(BOOST_ASIO_NO_TS_EXECUTORS) private: template <typename, typename, typename> friend class basic_system_executor; // Constructor used by require(). basic_system_executor(const Allocator& a) : allocator_(a) { } /// Execution helper implementation for the possibly blocking property. template <typename Function> void do_execute(Function&& f, execution::blocking_t::possibly_t) const; /// Execution helper implementation for the always blocking property. template <typename Function> void do_execute(Function&& f, execution::blocking_t::always_t) const; /// Execution helper implementation for the never blocking property. template <typename Function> void do_execute(Function&& f, execution::blocking_t::never_t) const; // The allocator used for execution functions. Allocator allocator_; }; /// An executor that uses arbitrary threads. /** * The system executor represents an execution context where functions are * permitted to run on arbitrary threads. When the blocking.never property is * established, the system executor will schedule the function to run on an * unspecified system thread pool. When either blocking.possibly or * blocking.always is established, the executor invokes the function * immediately. */ typedef basic_system_executor<execution::blocking_t::possibly_t, execution::relationship_t::fork_t, std::allocator<void>> system_executor; #if !defined(GENERATING_DOCUMENTATION) namespace traits { #if !defined(BOOST_ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) template <typename Blocking, typename Relationship, typename Allocator> struct equality_comparable< boost::asio::basic_system_executor<Blocking, Relationship, Allocator> > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT) template <typename Blocking, typename Relationship, typename Allocator, typename Function> struct execute_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, Function > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef void result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) template <typename Blocking, typename Relationship, typename Allocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::blocking_t::possibly_t > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor< boost::asio::execution::blocking_t::possibly_t, Relationship, Allocator> result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::blocking_t::always_t > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor< boost::asio::execution::blocking_t::always_t, Relationship, Allocator> result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::blocking_t::never_t > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor< boost::asio::execution::blocking_t::never_t, Relationship, Allocator> result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::relationship_t::fork_t > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor<Blocking, boost::asio::execution::relationship_t::fork_t, Allocator> result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::relationship_t::continuation_t > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor<Blocking, boost::asio::execution::relationship_t::continuation_t, Allocator> result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::allocator_t<void> > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor<Blocking, Relationship, std::allocator<void>> result_type; }; template <typename Blocking, typename Relationship, typename Allocator, typename OtherAllocator> struct require_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::allocator_t<OtherAllocator> > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef boost::asio::basic_system_executor<Blocking, Relationship, OtherAllocator> result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) template <typename Blocking, typename Relationship, typename Allocator, typename Property> struct query_static_constexpr_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, Property, typename boost::asio::enable_if< boost::asio::is_convertible< Property, boost::asio::execution::mapping_t >::value >::type > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef boost::asio::execution::mapping_t::thread_t result_type; static constexpr result_type value() noexcept { return result_type(); } }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) template <typename Blocking, typename Relationship, typename Allocator, typename Property> struct query_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, Property, typename boost::asio::enable_if< boost::asio::is_convertible< Property, boost::asio::execution::blocking_t >::value >::type > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef boost::asio::execution::blocking_t result_type; }; template <typename Blocking, typename Relationship, typename Allocator, typename Property> struct query_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, Property, typename boost::asio::enable_if< boost::asio::is_convertible< Property, boost::asio::execution::relationship_t >::value >::type > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef boost::asio::execution::relationship_t result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct query_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::context_t > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef boost::asio::system_context& result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct query_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::allocator_t<void> > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef Allocator result_type; }; template <typename Blocking, typename Relationship, typename Allocator> struct query_member< boost::asio::basic_system_executor<Blocking, Relationship, Allocator>, boost::asio::execution::allocator_t<Allocator> > { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef Allocator result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) } // namespace traits #endif // !defined(GENERATING_DOCUMENTATION) } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #include <boost/asio/impl/system_executor.hpp> #endif // BOOST_ASIO_SYSTEM_EXECUTOR_HPP