// // execution/blocking_adaptation.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 ASIO_EXECUTION_BLOCKING_ADAPTATION_HPP #define ASIO_EXECUTION_BLOCKING_ADAPTATION_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include "asio/detail/config.hpp" #include "asio/detail/event.hpp" #include "asio/detail/mutex.hpp" #include "asio/detail/type_traits.hpp" #include "asio/execution/executor.hpp" #include "asio/is_applicable_property.hpp" #include "asio/prefer.hpp" #include "asio/query.hpp" #include "asio/require.hpp" #include "asio/traits/prefer_member.hpp" #include "asio/traits/query_free.hpp" #include "asio/traits/query_member.hpp" #include "asio/traits/query_static_constexpr_member.hpp" #include "asio/traits/require_member.hpp" #include "asio/traits/static_query.hpp" #include "asio/traits/static_require.hpp" #include "asio/detail/push_options.hpp" namespace asio { #if defined(GENERATING_DOCUMENTATION) namespace execution { /// A property to describe whether automatic adaptation of an executor is /// allowed in order to apply the blocking_adaptation_t::allowed_t property. struct blocking_adaptation_t { /// The blocking_adaptation_t property applies to executors. template static constexpr bool is_applicable_property_v = is_executor_v; /// The top-level blocking_adaptation_t property cannot be required. static constexpr bool is_requirable = false; /// The top-level blocking_adaptation_t property cannot be preferred. static constexpr bool is_preferable = false; /// The type returned by queries against an @c any_executor. typedef blocking_adaptation_t polymorphic_query_result_type; /// A sub-property that indicates that automatic adaptation is not allowed. struct disallowed_t { /// The blocking_adaptation_t::disallowed_t property applies to executors. template static constexpr bool is_applicable_property_v = is_executor_v; /// The blocking_adaptation_t::disallowed_t property can be required. static constexpr bool is_requirable = true; /// The blocking_adaptation_t::disallowed_t property can be preferred. static constexpr bool is_preferable = true; /// The type returned by queries against an @c any_executor. typedef blocking_adaptation_t polymorphic_query_result_type; /// Default constructor. constexpr disallowed_t(); /// Get the value associated with a property object. /** * @returns disallowed_t(); */ static constexpr blocking_adaptation_t value(); }; /// A sub-property that indicates that automatic adaptation is allowed. struct allowed_t { /// The blocking_adaptation_t::allowed_t property applies to executors. template static constexpr bool is_applicable_property_v = is_executor_v; /// The blocking_adaptation_t::allowed_t property can be required. static constexpr bool is_requirable = true; /// The blocking_adaptation_t::allowed_t property can be preferred. static constexpr bool is_preferable = false; /// The type returned by queries against an @c any_executor. typedef blocking_adaptation_t polymorphic_query_result_type; /// Default constructor. constexpr allowed_t(); /// Get the value associated with a property object. /** * @returns allowed_t(); */ static constexpr blocking_adaptation_t value(); }; /// A special value used for accessing the blocking_adaptation_t::disallowed_t /// property. static constexpr disallowed_t disallowed; /// A special value used for accessing the blocking_adaptation_t::allowed_t /// property. static constexpr allowed_t allowed; /// Default constructor. constexpr blocking_adaptation_t(); /// Construct from a sub-property value. constexpr blocking_adaptation_t(disallowed_t); /// Construct from a sub-property value. constexpr blocking_adaptation_t(allowed_t); /// Compare property values for equality. friend constexpr bool operator==( const blocking_adaptation_t& a, const blocking_adaptation_t& b) noexcept; /// Compare property values for inequality. friend constexpr bool operator!=( const blocking_adaptation_t& a, const blocking_adaptation_t& b) noexcept; }; /// A special value used for accessing the blocking_adaptation_t property. constexpr blocking_adaptation_t blocking_adaptation; } // namespace execution #else // defined(GENERATING_DOCUMENTATION) namespace execution { namespace detail { namespace blocking_adaptation { template struct disallowed_t; template struct allowed_t; } // namespace blocking_adaptation template struct blocking_adaptation_t { #if defined(ASIO_HAS_VARIABLE_TEMPLATES) template static constexpr bool is_applicable_property_v = is_executor::value; #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES) static constexpr bool is_requirable = false; static constexpr bool is_preferable = false; typedef blocking_adaptation_t polymorphic_query_result_type; typedef detail::blocking_adaptation::disallowed_t disallowed_t; typedef detail::blocking_adaptation::allowed_t allowed_t; constexpr blocking_adaptation_t() : value_(-1) { } constexpr blocking_adaptation_t(disallowed_t) : value_(0) { } constexpr blocking_adaptation_t(allowed_t) : value_(1) { } template struct proxy { #if defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) struct type { template auto query(P&& p) const noexcept( noexcept( declval>().query(static_cast(p)) ) ) -> decltype( declval>().query(static_cast(p)) ); }; #else // defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) typedef T type; #endif // defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) }; template struct static_proxy { #if defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) struct type { template static constexpr auto query(P&& p) noexcept( noexcept( conditional_t::query(static_cast(p)) ) ) -> decltype( conditional_t::query(static_cast(p)) ) { return T::query(static_cast(p)); } }; #else // defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) typedef T type; #endif // defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) }; template struct query_member : traits::query_member::type, blocking_adaptation_t> {}; template struct query_static_constexpr_member : traits::query_static_constexpr_member< typename static_proxy::type, blocking_adaptation_t> {}; #if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template static constexpr typename query_static_constexpr_member::result_type static_query() noexcept(query_static_constexpr_member::is_noexcept) { return query_static_constexpr_member::value(); } template static constexpr typename traits::static_query::result_type static_query( enable_if_t< !query_static_constexpr_member::is_valid >* = 0, enable_if_t< !query_member::is_valid >* = 0, enable_if_t< traits::static_query::is_valid >* = 0) noexcept { return traits::static_query::value(); } template static constexpr typename traits::static_query::result_type static_query( enable_if_t< !query_static_constexpr_member::is_valid >* = 0, enable_if_t< !query_member::is_valid >* = 0, enable_if_t< !traits::static_query::is_valid >* = 0, enable_if_t< traits::static_query::is_valid >* = 0) noexcept { return traits::static_query::value(); } template ())> static constexpr const T static_query_v = blocking_adaptation_t::static_query(); #endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) friend constexpr bool operator==( const blocking_adaptation_t& a, const blocking_adaptation_t& b) { return a.value_ == b.value_; } friend constexpr bool operator!=( const blocking_adaptation_t& a, const blocking_adaptation_t& b) { return a.value_ != b.value_; } struct convertible_from_blocking_adaptation_t { constexpr convertible_from_blocking_adaptation_t( blocking_adaptation_t) { } }; template friend constexpr blocking_adaptation_t query( const Executor& ex, convertible_from_blocking_adaptation_t, enable_if_t< can_query::value >* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(ASIO_MSVC) // Visual C++ wants the type to be qualified. noexcept(is_nothrow_query::disallowed_t>::value) #else // defined(ASIO_MSVC) noexcept(is_nothrow_query::value) #endif // defined(ASIO_MSVC) #endif // !defined(__clang__) { return asio::query(ex, disallowed_t()); } template friend constexpr blocking_adaptation_t query( const Executor& ex, convertible_from_blocking_adaptation_t, enable_if_t< !can_query::value >* = 0, enable_if_t< can_query::value >* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(ASIO_MSVC) // Visual C++ wants the type to be qualified. noexcept(is_nothrow_query::allowed_t>::value) #else // defined(ASIO_MSVC) noexcept(is_nothrow_query::value) #endif // defined(ASIO_MSVC) #endif // !defined(__clang__) { return asio::query(ex, allowed_t()); } ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(disallowed_t, disallowed); ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(allowed_t, allowed); private: int value_; }; #if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template template const T blocking_adaptation_t::static_query_v; #endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template const typename blocking_adaptation_t::disallowed_t blocking_adaptation_t::disallowed; template const typename blocking_adaptation_t::allowed_t blocking_adaptation_t::allowed; namespace blocking_adaptation { template struct disallowed_t { #if defined(ASIO_HAS_VARIABLE_TEMPLATES) template static constexpr bool is_applicable_property_v = is_executor::value; #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES) static constexpr bool is_requirable = true; static constexpr bool is_preferable = true; typedef blocking_adaptation_t polymorphic_query_result_type; constexpr disallowed_t() { } template struct query_member : traits::query_member< typename blocking_adaptation_t::template proxy::type, disallowed_t> {}; template struct query_static_constexpr_member : traits::query_static_constexpr_member< typename blocking_adaptation_t::template static_proxy::type, disallowed_t> {}; #if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template static constexpr typename query_static_constexpr_member::result_type static_query() noexcept(query_static_constexpr_member::is_noexcept) { return query_static_constexpr_member::value(); } template static constexpr disallowed_t static_query( enable_if_t< !query_static_constexpr_member::is_valid >* = 0, enable_if_t< !query_member::is_valid >* = 0, enable_if_t< !traits::query_free::is_valid >* = 0, enable_if_t< !can_query>::value >* = 0) noexcept { return disallowed_t(); } template ())> static constexpr const T static_query_v = disallowed_t::static_query(); #endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static constexpr blocking_adaptation_t value() { return disallowed_t(); } friend constexpr bool operator==(const disallowed_t&, const disallowed_t&) { return true; } friend constexpr bool operator!=(const disallowed_t&, const disallowed_t&) { return false; } friend constexpr bool operator==(const disallowed_t&, const allowed_t&) { return false; } friend constexpr bool operator!=(const disallowed_t&, const allowed_t&) { return true; } }; #if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template template const T disallowed_t::static_query_v; #endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template class adapter { public: adapter(int, const Executor& e) noexcept : executor_(e) { } adapter(const adapter& other) noexcept : executor_(other.executor_) { } adapter(adapter&& other) noexcept : executor_(static_cast(other.executor_)) { } template static constexpr allowed_t query(blocking_adaptation_t) noexcept { return allowed_t(); } template static constexpr allowed_t query(allowed_t) noexcept { return allowed_t(); } template static constexpr allowed_t query(disallowed_t) noexcept { return allowed_t(); } template enable_if_t< can_query::value, query_result_t > query(const Property& p) const noexcept(is_nothrow_query::value) { return asio::query(executor_, p); } template Executor require(disallowed_t) const noexcept { return executor_; } template enable_if_t< can_require::value, adapter>> > require(const Property& p) const noexcept(is_nothrow_require::value) { return adapter>>( 0, asio::require(executor_, p)); } template enable_if_t< can_prefer::value, adapter>> > prefer(const Property& p) const noexcept(is_nothrow_prefer::value) { return adapter>>( 0, asio::prefer(executor_, p)); } template enable_if_t< traits::execute_member::is_valid > execute(Function&& f) const { executor_.execute(static_cast(f)); } friend bool operator==(const adapter& a, const adapter& b) noexcept { return a.executor_ == b.executor_; } friend bool operator!=(const adapter& a, const adapter& b) noexcept { return a.executor_ != b.executor_; } private: Executor executor_; }; template struct allowed_t { #if defined(ASIO_HAS_VARIABLE_TEMPLATES) template static constexpr bool is_applicable_property_v = is_executor::value; #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES) static constexpr bool is_requirable = true; static constexpr bool is_preferable = false; typedef blocking_adaptation_t polymorphic_query_result_type; constexpr allowed_t() { } template struct query_member : traits::query_member< typename blocking_adaptation_t::template proxy::type, allowed_t> {}; template struct query_static_constexpr_member : traits::query_static_constexpr_member< typename blocking_adaptation_t::template static_proxy::type, allowed_t> {}; #if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template static constexpr typename query_static_constexpr_member::result_type static_query() noexcept(query_static_constexpr_member::is_noexcept) { return query_static_constexpr_member::value(); } template ())> static constexpr const T static_query_v = allowed_t::static_query(); #endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static constexpr blocking_adaptation_t value() { return allowed_t(); } friend constexpr bool operator==(const allowed_t&, const allowed_t&) { return true; } friend constexpr bool operator!=(const allowed_t&, const allowed_t&) { return false; } friend constexpr bool operator==(const allowed_t&, const disallowed_t&) { return false; } friend constexpr bool operator!=(const allowed_t&, const disallowed_t&) { return true; } template friend adapter require( const Executor& e, const allowed_t&, enable_if_t< is_executor::value >* = 0) { return adapter(0, e); } }; #if defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template template const T allowed_t::static_query_v; #endif // defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template class blocking_execute_state { public: template blocking_execute_state(F&& f) : func_(static_cast(f)), is_complete_(false) { } template void execute_and_wait(Executor&& ex) { handler h = { this }; ex.execute(h); asio::detail::mutex::scoped_lock lock(mutex_); while (!is_complete_) event_.wait(lock); } struct cleanup { ~cleanup() { asio::detail::mutex::scoped_lock lock(state_->mutex_); state_->is_complete_ = true; state_->event_.unlock_and_signal_one_for_destruction(lock); } blocking_execute_state* state_; }; struct handler { void operator()() { cleanup c = { state_ }; state_->func_(); } blocking_execute_state* state_; }; Function func_; asio::detail::mutex mutex_; asio::detail::event event_; bool is_complete_; }; template void blocking_execute( Executor&& ex, Function&& func) { typedef decay_t func_t; blocking_execute_state state(static_cast(func)); state.execute_and_wait(ex); } } // namespace blocking_adaptation } // namespace detail typedef detail::blocking_adaptation_t<> blocking_adaptation_t; constexpr blocking_adaptation_t blocking_adaptation; } // namespace execution #if !defined(ASIO_HAS_VARIABLE_TEMPLATES) template struct is_applicable_property : integral_constant::value> { }; template struct is_applicable_property : integral_constant::value> { }; template struct is_applicable_property : integral_constant::value> { }; #endif // !defined(ASIO_HAS_VARIABLE_TEMPLATES) namespace traits { #if !defined(ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT) template struct query_free_default::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = is_nothrow_query::value; typedef execution::blocking_adaptation_t result_type; }; template struct query_free_default::value && can_query::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = is_nothrow_query::value; typedef execution::blocking_adaptation_t result_type; }; #endif // !defined(ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT) #if !defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ || !defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template struct static_query:: query_static_constexpr_member::is_valid >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef typename execution::detail::blocking_adaptation_t<0>:: query_static_constexpr_member::result_type result_type; static constexpr result_type value() { return execution::detail::blocking_adaptation_t<0>:: query_static_constexpr_member::value(); } }; template struct static_query:: query_static_constexpr_member::is_valid && !execution::detail::blocking_adaptation_t<0>:: query_member::is_valid && traits::static_query::is_valid >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef typename traits::static_query::result_type result_type; static constexpr result_type value() { return traits::static_query::value(); } }; template struct static_query:: query_static_constexpr_member::is_valid && !execution::detail::blocking_adaptation_t<0>:: query_member::is_valid && !traits::static_query::is_valid && traits::static_query::is_valid >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef typename traits::static_query::result_type result_type; static constexpr result_type value() { return traits::static_query::value(); } }; template struct static_query:: query_static_constexpr_member::is_valid >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef typename execution::detail::blocking_adaptation::disallowed_t<0>:: query_static_constexpr_member::result_type result_type; static constexpr result_type value() { return execution::detail::blocking_adaptation::disallowed_t<0>:: query_static_constexpr_member::value(); } }; template struct static_query:: query_static_constexpr_member::is_valid && !execution::detail::blocking_adaptation::disallowed_t<0>:: query_member::is_valid && !traits::query_free::is_valid && !can_query::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef execution::blocking_adaptation_t::disallowed_t result_type; static constexpr result_type value() { return result_type(); } }; template struct static_query:: query_static_constexpr_member::is_valid >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef typename execution::detail::blocking_adaptation::allowed_t<0>:: query_static_constexpr_member::result_type result_type; static constexpr result_type value() { return execution::detail::blocking_adaptation::allowed_t<0>:: query_static_constexpr_member::value(); } }; #endif // !defined(ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // || !defined(ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) #if !defined(ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) template struct require_free_default>::value && execution::is_executor::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef execution::detail::blocking_adaptation::adapter result_type; }; #endif // !defined(ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) #if !defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) template struct equality_comparable< execution::detail::blocking_adaptation::adapter> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; }; #endif // !defined(ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) #if !defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT) template struct execute_member< execution::detail::blocking_adaptation::adapter, Function> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = false; typedef void result_type; }; #endif // !defined(ASIO_HAS_DEDUCED_EXECUTE_MEMBER_TRAIT) #if !defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) template struct query_static_constexpr_member< execution::detail::blocking_adaptation::adapter, execution::detail::blocking_adaptation_t> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef execution::blocking_adaptation_t::allowed_t result_type; static constexpr result_type value() noexcept { return result_type(); } }; template struct query_static_constexpr_member< execution::detail::blocking_adaptation::adapter, execution::detail::blocking_adaptation::allowed_t> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef execution::blocking_adaptation_t::allowed_t result_type; static constexpr result_type value() noexcept { return result_type(); } }; template struct query_static_constexpr_member< execution::detail::blocking_adaptation::adapter, execution::detail::blocking_adaptation::disallowed_t> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef execution::blocking_adaptation_t::allowed_t result_type; static constexpr result_type value() noexcept { return result_type(); } }; #endif // !defined(ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) #if !defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) template struct query_member< execution::detail::blocking_adaptation::adapter, Property, enable_if_t< can_query::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = is_nothrow_query::value; typedef query_result_t result_type; }; #endif // !defined(ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) #if !defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) template struct require_member< execution::detail::blocking_adaptation::adapter, execution::detail::blocking_adaptation::disallowed_t> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = true; typedef Executor result_type; }; template struct require_member< execution::detail::blocking_adaptation::adapter, Property, enable_if_t< can_require::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = is_nothrow_require::value; typedef execution::detail::blocking_adaptation::adapter< decay_t>> result_type; }; #endif // !defined(ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) #if !defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT) template struct prefer_member< execution::detail::blocking_adaptation::adapter, Property, enable_if_t< can_prefer::value >> { static constexpr bool is_valid = true; static constexpr bool is_noexcept = is_nothrow_prefer::value; typedef execution::detail::blocking_adaptation::adapter< decay_t>> result_type; }; #endif // !defined(ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT) } // namespace traits #endif // defined(GENERATING_DOCUMENTATION) } // namespace asio #include "asio/detail/pop_options.hpp" #endif // ASIO_EXECUTION_BLOCKING_ADAPTATION_HPP