boost/asio/execution/blocking.hpp
// // execution/blocking.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_EXECUTION_BLOCKING_HPP #define BOOST_ASIO_EXECUTION_BLOCKING_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/type_traits.hpp> #include <boost/asio/execution/execute.hpp> #include <boost/asio/execution/executor.hpp> #include <boost/asio/execution/scheduler.hpp> #include <boost/asio/execution/sender.hpp> #include <boost/asio/is_applicable_property.hpp> #include <boost/asio/prefer.hpp> #include <boost/asio/query.hpp> #include <boost/asio/require.hpp> #include <boost/asio/traits/query_free.hpp> #include <boost/asio/traits/query_member.hpp> #include <boost/asio/traits/query_static_constexpr_member.hpp> #include <boost/asio/traits/static_query.hpp> #include <boost/asio/traits/static_require.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { #if defined(GENERATING_DOCUMENTATION) namespace execution { /// A property to describe what guarantees an executor makes about the blocking /// behaviour of their execution functions. struct blocking_t { /// The blocking_t property applies to executors, senders, and schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The top-level blocking_t property cannot be required. static constexpr bool is_requirable = false; /// The top-level blocking_t property cannot be preferred. static constexpr bool is_preferable = false; /// The type returned by queries against an @c any_executor. typedef blocking_t polymorphic_query_result_type; /// A sub-property that indicates that invocation of an executor's execution /// function may block pending completion of one or more invocations of the /// submitted function object. struct possibly_t { /// The blocking_t::possibly_t property applies to executors, senders, and /// schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The blocking_t::possibly_t property can be required. static constexpr bool is_requirable = true; /// The blocking_t::possibly_t property can be preferred. static constexpr bool is_preferable = true; /// The type returned by queries against an @c any_executor. typedef blocking_t polymorphic_query_result_type; /// Default constructor. constexpr possibly_t(); /// Get the value associated with a property object. /** * @returns possibly_t(); */ static constexpr blocking_t value(); }; /// A sub-property that indicates that invocation of an executor's execution /// function shall block until completion of all invocations of the submitted /// function object. struct always_t { /// The blocking_t::always_t property applies to executors, senders, and /// schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The blocking_t::always_t property can be required. static constexpr bool is_requirable = true; /// The blocking_t::always_t property can be preferred. static constexpr bool is_preferable = false; /// The type returned by queries against an @c any_executor. typedef blocking_t polymorphic_query_result_type; /// Default constructor. constexpr always_t(); /// Get the value associated with a property object. /** * @returns always_t(); */ static constexpr blocking_t value(); }; /// A sub-property that indicates that invocation of an executor's execution /// function shall not block pending completion of the invocations of the /// submitted function object. struct never_t { /// The blocking_t::never_t property applies to executors, senders, and /// schedulers. template <typename T> static constexpr bool is_applicable_property_v = is_executor_v<T> || is_sender_v<T> || is_scheduler_v<T>; /// The blocking_t::never_t property can be required. static constexpr bool is_requirable = true; /// The blocking_t::never_t property can be preferred. static constexpr bool is_preferable = true; /// The type returned by queries against an @c any_executor. typedef blocking_t polymorphic_query_result_type; /// Default constructor. constexpr never_t(); /// Get the value associated with a property object. /** * @returns never_t(); */ static constexpr blocking_t value(); }; /// A special value used for accessing the blocking_t::possibly_t property. static constexpr possibly_t possibly; /// A special value used for accessing the blocking_t::always_t property. static constexpr always_t always; /// A special value used for accessing the blocking_t::never_t property. static constexpr never_t never; /// Default constructor. constexpr blocking_t(); /// Construct from a sub-property value. constexpr blocking_t(possibly_t); /// Construct from a sub-property value. constexpr blocking_t(always_t); /// Construct from a sub-property value. constexpr blocking_t(never_t); /// Compare property values for equality. friend constexpr bool operator==( const blocking_t& a, const blocking_t& b) noexcept; /// Compare property values for inequality. friend constexpr bool operator!=( const blocking_t& a, const blocking_t& b) noexcept; }; /// A special value used for accessing the blocking_t property. constexpr blocking_t blocking; } // namespace execution #else // defined(GENERATING_DOCUMENTATION) namespace execution { namespace detail { namespace blocking { template <int I> struct possibly_t; template <int I> struct always_t; template <int I> struct never_t; } // namespace blocking namespace blocking_adaptation { template <int I> struct allowed_t; template <typename Executor, typename Function> void blocking_execute( BOOST_ASIO_MOVE_ARG(Executor) ex, BOOST_ASIO_MOVE_ARG(Function) func); } // namespace blocking_adaptation template <int I = 0> struct blocking_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value)); #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = false); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = false); typedef blocking_t polymorphic_query_result_type; typedef detail::blocking::possibly_t<I> possibly_t; typedef detail::blocking::always_t<I> always_t; typedef detail::blocking::never_t<I> never_t; BOOST_ASIO_CONSTEXPR blocking_t() : value_(-1) { } BOOST_ASIO_CONSTEXPR blocking_t(possibly_t) : value_(0) { } BOOST_ASIO_CONSTEXPR blocking_t(always_t) : value_(1) { } BOOST_ASIO_CONSTEXPR blocking_t(never_t) : value_(2) { } template <typename T> struct proxy { #if defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) struct type { template <typename P> auto query(BOOST_ASIO_MOVE_ARG(P) p) const noexcept( noexcept( declval<typename conditional<true, T, P>::type>().query( BOOST_ASIO_MOVE_CAST(P)(p)) ) ) -> decltype( declval<typename conditional<true, T, P>::type>().query( BOOST_ASIO_MOVE_CAST(P)(p)) ); }; #else // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) typedef T type; #endif // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) }; template <typename T> struct static_proxy { #if defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) struct type { template <typename P> static constexpr auto query(BOOST_ASIO_MOVE_ARG(P) p) noexcept( noexcept( conditional<true, T, P>::type::query(BOOST_ASIO_MOVE_CAST(P)(p)) ) ) -> decltype( conditional<true, T, P>::type::query(BOOST_ASIO_MOVE_CAST(P)(p)) ) { return T::query(BOOST_ASIO_MOVE_CAST(P)(p)); } }; #else // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) typedef T type; #endif // defined(BOOST_ASIO_HAS_DEDUCED_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) }; template <typename T> struct query_member : traits::query_member<typename proxy<T>::type, blocking_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename static_proxy<T>::type, blocking_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR typename traits::static_query<T, possibly_t>::result_type static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< traits::static_query<T, possibly_t>::is_valid >::type* = 0) BOOST_ASIO_NOEXCEPT { return traits::static_query<T, possibly_t>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR typename traits::static_query<T, always_t>::result_type static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< !traits::static_query<T, possibly_t>::is_valid >::type* = 0, typename enable_if< traits::static_query<T, always_t>::is_valid >::type* = 0) BOOST_ASIO_NOEXCEPT { return traits::static_query<T, always_t>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR typename traits::static_query<T, never_t>::result_type static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< !traits::static_query<T, possibly_t>::is_valid >::type* = 0, typename enable_if< !traits::static_query<T, always_t>::is_valid >::type* = 0, typename enable_if< traits::static_query<T, never_t>::is_valid >::type* = 0) BOOST_ASIO_NOEXCEPT { return traits::static_query<T, never_t>::value(); } template <typename E, typename T = decltype(blocking_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = blocking_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) friend BOOST_ASIO_CONSTEXPR bool operator==( const blocking_t& a, const blocking_t& b) { return a.value_ == b.value_; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const blocking_t& a, const blocking_t& b) { return a.value_ != b.value_; } struct convertible_from_blocking_t { BOOST_ASIO_CONSTEXPR convertible_from_blocking_t(blocking_t) {} }; template <typename Executor> friend BOOST_ASIO_CONSTEXPR blocking_t query( const Executor& ex, convertible_from_blocking_t, typename enable_if< can_query<const Executor&, possibly_t>::value >::type* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(BOOST_ASIO_MSVC) // Visual C++ wants the type to be qualified. BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, blocking_t<>::possibly_t>::value)) #else // defined(BOOST_ASIO_MSVC) BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, possibly_t>::value)) #endif // defined(BOOST_ASIO_MSVC) #endif // !defined(__clang__) { return boost::asio::query(ex, possibly_t()); } template <typename Executor> friend BOOST_ASIO_CONSTEXPR blocking_t query( const Executor& ex, convertible_from_blocking_t, typename enable_if< !can_query<const Executor&, possibly_t>::value >::type* = 0, typename enable_if< can_query<const Executor&, always_t>::value >::type* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(BOOST_ASIO_MSVC) // Visual C++ wants the type to be qualified. BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, blocking_t<>::always_t>::value)) #else // defined(BOOST_ASIO_MSVC) BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, always_t>::value)) #endif // defined(BOOST_ASIO_MSVC) #endif // !defined(__clang__) { return boost::asio::query(ex, always_t()); } template <typename Executor> friend BOOST_ASIO_CONSTEXPR blocking_t query( const Executor& ex, convertible_from_blocking_t, typename enable_if< !can_query<const Executor&, possibly_t>::value >::type* = 0, typename enable_if< !can_query<const Executor&, always_t>::value >::type* = 0, typename enable_if< can_query<const Executor&, never_t>::value >::type* = 0) #if !defined(__clang__) // Clang crashes if noexcept is used here. #if defined(BOOST_ASIO_MSVC) // Visual C++ wants the type to be qualified. BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, blocking_t<>::never_t>::value)) #else // defined(BOOST_ASIO_MSVC) BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, never_t>::value)) #endif // defined(BOOST_ASIO_MSVC) #endif // !defined(__clang__) { return boost::asio::query(ex, never_t()); } BOOST_ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(possibly_t, possibly); BOOST_ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(always_t, always); BOOST_ASIO_STATIC_CONSTEXPR_DEFAULT_INIT(never_t, never); #if !defined(BOOST_ASIO_HAS_CONSTEXPR) static const blocking_t instance; #endif // !defined(BOOST_ASIO_HAS_CONSTEXPR) private: int value_; }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T blocking_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) #if !defined(BOOST_ASIO_HAS_CONSTEXPR) template <int I> const blocking_t<I> blocking_t<I>::instance; #endif template <int I> const typename blocking_t<I>::possibly_t blocking_t<I>::possibly; template <int I> const typename blocking_t<I>::always_t blocking_t<I>::always; template <int I> const typename blocking_t<I>::never_t blocking_t<I>::never; namespace blocking { template <int I = 0> struct possibly_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value)); #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = true); typedef blocking_t<I> polymorphic_query_result_type; BOOST_ASIO_CONSTEXPR possibly_t() { } template <typename T> struct query_member : traits::query_member< typename blocking_t<I>::template proxy<T>::type, possibly_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename blocking_t<I>::template static_proxy<T>::type, possibly_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename T> static BOOST_ASIO_CONSTEXPR possibly_t static_query( typename enable_if< !query_static_constexpr_member<T>::is_valid >::type* = 0, typename enable_if< !query_member<T>::is_valid >::type* = 0, typename enable_if< !traits::query_free<T, possibly_t>::is_valid >::type* = 0, typename enable_if< !can_query<T, always_t<I> >::value >::type* = 0, typename enable_if< !can_query<T, never_t<I> >::value >::type* = 0) BOOST_ASIO_NOEXCEPT { return possibly_t(); } template <typename E, typename T = decltype(possibly_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = possibly_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static BOOST_ASIO_CONSTEXPR blocking_t<I> value() { return possibly_t(); } friend BOOST_ASIO_CONSTEXPR bool operator==( const possibly_t&, const possibly_t&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const possibly_t&, const possibly_t&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator==( const possibly_t&, const always_t<I>&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const possibly_t&, const always_t<I>&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator==( const possibly_t&, const never_t<I>&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const possibly_t&, const never_t<I>&) { return true; } }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T possibly_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename Executor> class adapter { public: adapter(int, const Executor& e) BOOST_ASIO_NOEXCEPT : executor_(e) { } adapter(const adapter& other) BOOST_ASIO_NOEXCEPT : executor_(other.executor_) { } #if defined(BOOST_ASIO_HAS_MOVE) adapter(adapter&& other) BOOST_ASIO_NOEXCEPT : executor_(BOOST_ASIO_MOVE_CAST(Executor)(other.executor_)) { } #endif // defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) template <int I> static BOOST_ASIO_CONSTEXPR always_t<I> query( blocking_t<I>) BOOST_ASIO_NOEXCEPT { return always_t<I>(); } template <int I> static BOOST_ASIO_CONSTEXPR always_t<I> query( possibly_t<I>) BOOST_ASIO_NOEXCEPT { return always_t<I>(); } template <int I> static BOOST_ASIO_CONSTEXPR always_t<I> query( always_t<I>) BOOST_ASIO_NOEXCEPT { return always_t<I>(); } template <int I> static BOOST_ASIO_CONSTEXPR always_t<I> query( never_t<I>) BOOST_ASIO_NOEXCEPT { return always_t<I>(); } template <typename Property> typename enable_if< can_query<const Executor&, Property>::value, typename query_result<const Executor&, Property>::type >::type query(const Property& p) const BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_query<const Executor&, Property>::value)) { return boost::asio::query(executor_, p); } template <int I> typename enable_if< can_require<const Executor&, possibly_t<I> >::value, typename require_result<const Executor&, possibly_t<I> >::type >::type require(possibly_t<I>) const BOOST_ASIO_NOEXCEPT { return boost::asio::require(executor_, possibly_t<I>()); } template <int I> typename enable_if< can_require<const Executor&, never_t<I> >::value, typename require_result<const Executor&, never_t<I> >::type >::type require(never_t<I>) const BOOST_ASIO_NOEXCEPT { return boost::asio::require(executor_, never_t<I>()); } template <typename Property> typename enable_if< can_require<const Executor&, Property>::value, adapter<typename decay< typename require_result<const Executor&, Property>::type >::type> >::type require(const Property& p) const BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_require<const Executor&, Property>::value)) { return adapter<typename decay< typename require_result<const Executor&, Property>::type >::type>(0, boost::asio::require(executor_, p)); } template <typename Property> typename enable_if< can_prefer<const Executor&, Property>::value, adapter<typename decay< typename prefer_result<const Executor&, Property>::type >::type> >::type prefer(const Property& p) const BOOST_ASIO_NOEXCEPT_IF(( is_nothrow_prefer<const Executor&, Property>::value)) { return adapter<typename decay< typename prefer_result<const Executor&, Property>::type >::type>(0, boost::asio::prefer(executor_, p)); } template <typename Function> typename enable_if< execution::can_execute<const Executor&, Function>::value >::type execute(BOOST_ASIO_MOVE_ARG(Function) f) const { blocking_adaptation::blocking_execute( executor_, BOOST_ASIO_MOVE_CAST(Function)(f)); } friend bool operator==(const adapter& a, const adapter& b) BOOST_ASIO_NOEXCEPT { return a.executor_ == b.executor_; } friend bool operator!=(const adapter& a, const adapter& b) BOOST_ASIO_NOEXCEPT { return a.executor_ != b.executor_; } private: Executor executor_; }; template <int I = 0> struct always_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value)); #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = false); typedef blocking_t<I> polymorphic_query_result_type; BOOST_ASIO_CONSTEXPR always_t() { } template <typename T> struct query_member : traits::query_member< typename blocking_t<I>::template proxy<T>::type, always_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename blocking_t<I>::template static_proxy<T>::type, always_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename E, typename T = decltype(always_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = always_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static BOOST_ASIO_CONSTEXPR blocking_t<I> value() { return always_t(); } friend BOOST_ASIO_CONSTEXPR bool operator==( const always_t&, const always_t&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const always_t&, const always_t&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator==( const always_t&, const possibly_t<I>&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const always_t&, const possibly_t<I>&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator==( const always_t&, const never_t<I>&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const always_t&, const never_t<I>&) { return true; } template <typename Executor> friend adapter<Executor> require( const Executor& e, const always_t&, typename enable_if< is_executor<Executor>::value >::type* = 0, typename enable_if< traits::static_require< const Executor&, blocking_adaptation::allowed_t<0> >::is_valid >::type* = 0) { return adapter<Executor>(0, e); } }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T always_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> struct never_t { #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) template <typename T> BOOST_ASIO_STATIC_CONSTEXPR(bool, is_applicable_property_v = ( is_executor<T>::value || conditional< is_executor<T>::value, false_type, is_sender<T> >::type::value || conditional< is_executor<T>::value, false_type, is_scheduler<T> >::type::value)); #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) BOOST_ASIO_STATIC_CONSTEXPR(bool, is_requirable = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_preferable = true); typedef blocking_t<I> polymorphic_query_result_type; BOOST_ASIO_CONSTEXPR never_t() { } template <typename T> struct query_member : traits::query_member< typename blocking_t<I>::template proxy<T>::type, never_t> {}; template <typename T> struct query_static_constexpr_member : traits::query_static_constexpr_member< typename blocking_t<I>::template static_proxy<T>::type, never_t> {}; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> static BOOST_ASIO_CONSTEXPR typename query_static_constexpr_member<T>::result_type static_query() BOOST_ASIO_NOEXCEPT_IF(( query_static_constexpr_member<T>::is_noexcept)) { return query_static_constexpr_member<T>::value(); } template <typename E, typename T = decltype(never_t::static_query<E>())> static BOOST_ASIO_CONSTEXPR const T static_query_v = never_t::static_query<E>(); #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) static BOOST_ASIO_CONSTEXPR blocking_t<I> value() { return never_t(); } friend BOOST_ASIO_CONSTEXPR bool operator==( const never_t&, const never_t&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const never_t&, const never_t&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator==( const never_t&, const possibly_t<I>&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const never_t&, const possibly_t<I>&) { return true; } friend BOOST_ASIO_CONSTEXPR bool operator==( const never_t&, const always_t<I>&) { return false; } friend BOOST_ASIO_CONSTEXPR bool operator!=( const never_t&, const always_t<I>&) { return true; } }; #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ && defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <int I> template <typename E, typename T> const T never_t<I>::static_query_v; #endif // defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) } // namespace blocking } // namespace detail typedef detail::blocking_t<> blocking_t; #if defined(BOOST_ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) constexpr blocking_t blocking; #else // defined(BOOST_ASIO_HAS_CONSTEXPR) || defined(GENERATING_DOCUMENTATION) namespace { static const blocking_t& blocking = blocking_t::instance; } #endif } // namespace execution #if !defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) template <typename T> struct is_applicable_property<T, execution::blocking_t> : integral_constant<bool, execution::is_executor<T>::value || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value> { }; template <typename T> struct is_applicable_property<T, execution::blocking_t::possibly_t> : integral_constant<bool, execution::is_executor<T>::value || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value> { }; template <typename T> struct is_applicable_property<T, execution::blocking_t::always_t> : integral_constant<bool, execution::is_executor<T>::value || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value> { }; template <typename T> struct is_applicable_property<T, execution::blocking_t::never_t> : integral_constant<bool, execution::is_executor<T>::value || conditional< execution::is_executor<T>::value, false_type, execution::is_sender<T> >::type::value || conditional< execution::is_executor<T>::value, false_type, execution::is_scheduler<T> >::type::value> { }; #endif // !defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) namespace traits { #if !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT) template <typename T> struct query_free_default<T, execution::blocking_t, typename enable_if< can_query<T, execution::blocking_t::possibly_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_query<T, execution::blocking_t::possibly_t>::value)); typedef execution::blocking_t result_type; }; template <typename T> struct query_free_default<T, execution::blocking_t, typename enable_if< !can_query<T, execution::blocking_t::possibly_t>::value && can_query<T, execution::blocking_t::always_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_query<T, execution::blocking_t::always_t>::value)); typedef execution::blocking_t result_type; }; template <typename T> struct query_free_default<T, execution::blocking_t, typename enable_if< !can_query<T, execution::blocking_t::possibly_t>::value && !can_query<T, execution::blocking_t::always_t>::value && can_query<T, execution::blocking_t::never_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_query<T, execution::blocking_t::never_t>::value)); typedef execution::blocking_t result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_FREE_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) \ || !defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) template <typename T> struct static_query<T, execution::blocking_t, typename enable_if< execution::detail::blocking_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::blocking_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::blocking_t::query_static_constexpr_member<T>::value(); } }; template <typename T> struct static_query<T, execution::blocking_t, typename enable_if< !execution::detail::blocking_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::blocking_t<0>:: query_member<T>::is_valid && traits::static_query<T, execution::blocking_t::possibly_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename traits::static_query<T, execution::blocking_t::possibly_t>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return traits::static_query<T, execution::blocking_t::possibly_t>::value(); } }; template <typename T> struct static_query<T, execution::blocking_t, typename enable_if< !execution::detail::blocking_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::blocking_t<0>:: query_member<T>::is_valid && !traits::static_query<T, execution::blocking_t::possibly_t>::is_valid && traits::static_query<T, execution::blocking_t::always_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename traits::static_query<T, execution::blocking_t::always_t>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return traits::static_query<T, execution::blocking_t::always_t>::value(); } }; template <typename T> struct static_query<T, execution::blocking_t, typename enable_if< !execution::detail::blocking_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::blocking_t<0>:: query_member<T>::is_valid && !traits::static_query<T, execution::blocking_t::possibly_t>::is_valid && !traits::static_query<T, execution::blocking_t::always_t>::is_valid && traits::static_query<T, execution::blocking_t::never_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename traits::static_query<T, execution::blocking_t::never_t>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return traits::static_query<T, execution::blocking_t::never_t>::value(); } }; template <typename T> struct static_query<T, execution::blocking_t::possibly_t, typename enable_if< execution::detail::blocking::possibly_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::blocking::possibly_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::detail::blocking::possibly_t<0>:: query_static_constexpr_member<T>::value(); } }; template <typename T> struct static_query<T, execution::blocking_t::possibly_t, typename enable_if< !execution::detail::blocking::possibly_t<0>:: query_static_constexpr_member<T>::is_valid && !execution::detail::blocking::possibly_t<0>:: query_member<T>::is_valid && !traits::query_free<T, execution::blocking_t::possibly_t>::is_valid && !can_query<T, execution::blocking_t::always_t>::value && !can_query<T, execution::blocking_t::never_t>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef execution::blocking_t::possibly_t result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return result_type(); } }; template <typename T> struct static_query<T, execution::blocking_t::always_t, typename enable_if< execution::detail::blocking::always_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::blocking::always_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::detail::blocking::always_t<0>:: query_static_constexpr_member<T>::value(); } }; template <typename T> struct static_query<T, execution::blocking_t::never_t, typename enable_if< execution::detail::blocking::never_t<0>:: query_static_constexpr_member<T>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef typename execution::detail::blocking::never_t<0>:: query_static_constexpr_member<T>::result_type result_type; static BOOST_ASIO_CONSTEXPR result_type value() { return execution::detail::blocking::never_t<0>:: query_static_constexpr_member<T>::value(); } }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) // || !defined(BOOST_ASIO_HAS_SFINAE_VARIABLE_TEMPLATES) #if !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT) template <typename T> struct static_require<T, execution::blocking_t::possibly_t, typename enable_if< static_query<T, execution::blocking_t::possibly_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = (is_same<typename static_query<T, execution::blocking_t::possibly_t>::result_type, execution::blocking_t::possibly_t>::value)); }; template <typename T> struct static_require<T, execution::blocking_t::always_t, typename enable_if< static_query<T, execution::blocking_t::always_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = (is_same<typename static_query<T, execution::blocking_t::always_t>::result_type, execution::blocking_t::always_t>::value)); }; template <typename T> struct static_require<T, execution::blocking_t::never_t, typename enable_if< static_query<T, execution::blocking_t::never_t>::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = (is_same<typename static_query<T, execution::blocking_t::never_t>::result_type, execution::blocking_t::never_t>::value)); }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) template <typename T> struct require_free_default<T, execution::blocking_t::always_t, typename enable_if< is_same<T, typename decay<T>::type>::value && execution::is_executor<T>::value && traits::static_require< const T&, execution::detail::blocking_adaptation::allowed_t<0> >::is_valid >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false); typedef execution::detail::blocking::adapter<T> result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_FREE_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT) template <typename Executor> struct equality_comparable< execution::detail::blocking::adapter<Executor> > { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_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 Executor, typename Function> struct execute_member< execution::detail::blocking::adapter<Executor>, Function> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_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_QUERY_STATIC_CONSTEXPR_MEMBER_TRAIT) template <typename Executor, int I> struct query_static_constexpr_member< execution::detail::blocking::adapter<Executor>, execution::detail::blocking_t<I> > { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef execution::blocking_t::always_t result_type; static BOOST_ASIO_CONSTEXPR result_type value() BOOST_ASIO_NOEXCEPT { return result_type(); } }; template <typename Executor, int I> struct query_static_constexpr_member< execution::detail::blocking::adapter<Executor>, execution::detail::blocking::always_t<I> > { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef execution::blocking_t::always_t result_type; static BOOST_ASIO_CONSTEXPR result_type value() BOOST_ASIO_NOEXCEPT { return result_type(); } }; template <typename Executor, int I> struct query_static_constexpr_member< execution::detail::blocking::adapter<Executor>, execution::detail::blocking::possibly_t<I> > { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef execution::blocking_t::always_t result_type; static BOOST_ASIO_CONSTEXPR result_type value() BOOST_ASIO_NOEXCEPT { return result_type(); } }; template <typename Executor, int I> struct query_static_constexpr_member< execution::detail::blocking::adapter<Executor>, execution::detail::blocking::never_t<I> > { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = true); typedef execution::blocking_t::always_t result_type; static BOOST_ASIO_CONSTEXPR result_type value() BOOST_ASIO_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 Executor, typename Property> struct query_member< execution::detail::blocking::adapter<Executor>, Property, typename enable_if< can_query<const Executor&, Property>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_query<Executor, Property>::value)); typedef typename query_result<Executor, Property>::type result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_QUERY_MEMBER_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) template <typename Executor, int I> struct require_member< execution::detail::blocking::adapter<Executor>, execution::detail::blocking::possibly_t<I>, typename enable_if< can_require< const Executor&, execution::detail::blocking::possibly_t<I> >::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_require<const Executor&, execution::detail::blocking::possibly_t<I> >::value)); typedef typename require_result<const Executor&, execution::detail::blocking::possibly_t<I> >::type result_type; }; template <typename Executor, int I> struct require_member< execution::detail::blocking::adapter<Executor>, execution::detail::blocking::never_t<I>, typename enable_if< can_require< const Executor&, execution::detail::blocking::never_t<I> >::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_require<const Executor&, execution::detail::blocking::never_t<I> >::value)); typedef typename require_result<const Executor&, execution::detail::blocking::never_t<I> >::type result_type; }; template <typename Executor, typename Property> struct require_member< execution::detail::blocking::adapter<Executor>, Property, typename enable_if< can_require<const Executor&, Property>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_require<Executor, Property>::value)); typedef execution::detail::blocking::adapter<typename decay< typename require_result<Executor, Property>::type >::type> result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_REQUIRE_MEMBER_TRAIT) #if !defined(BOOST_ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT) template <typename Executor, typename Property> struct prefer_member< execution::detail::blocking::adapter<Executor>, Property, typename enable_if< can_prefer<const Executor&, Property>::value >::type> { BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = (is_nothrow_prefer<Executor, Property>::value)); typedef execution::detail::blocking::adapter<typename decay< typename prefer_result<Executor, Property>::type >::type> result_type; }; #endif // !defined(BOOST_ASIO_HAS_DEDUCED_PREFER_MEMBER_TRAIT) } // namespace traits #endif // defined(GENERATING_DOCUMENTATION) } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_EXECUTION_BLOCKING_HPP