| // |
| // traits/static_query.hpp |
| // ~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2021 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_TRAITS_STATIC_QUERY_HPP |
| #define BOOST_ASIO_TRAITS_STATIC_QUERY_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> |
| |
| #if defined(BOOST_ASIO_HAS_DECLTYPE) \ |
| && defined(BOOST_ASIO_HAS_NOEXCEPT) \ |
| && defined(BOOST_ASIO_HAS_CONSTEXPR) \ |
| && defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) \ |
| && defined(BOOST_ASIO_HAS_WORKING_EXPRESSION_SFINAE) |
| # define BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT 1 |
| #endif // defined(BOOST_ASIO_HAS_DECLTYPE) |
| // && defined(BOOST_ASIO_HAS_NOEXCEPT) |
| // && defined(BOOST_ASIO_HAS_CONSTEXPR) |
| // && defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES) |
| // && defined(BOOST_ASIO_HAS_WORKING_EXPRESSION_SFINAE) |
| |
| #include <boost/asio/detail/push_options.hpp> |
| |
| namespace boost { |
| namespace asio { |
| namespace traits { |
| |
| template <typename T, typename Property, typename = void> |
| struct static_query_default; |
| |
| template <typename T, typename Property, typename = void> |
| struct static_query; |
| |
| } // namespace traits |
| namespace detail { |
| |
| struct no_static_query |
| { |
| BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = false); |
| BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false); |
| }; |
| |
| template <typename T, typename Property, typename = void> |
| struct static_query_trait : |
| conditional< |
| is_same<T, typename decay<T>::type>::value |
| && is_same<Property, typename decay<Property>::type>::value, |
| no_static_query, |
| traits::static_query< |
| typename decay<T>::type, |
| typename decay<Property>::type> |
| >::type |
| { |
| }; |
| |
| #if defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) |
| |
| template <typename T, typename Property> |
| struct static_query_trait<T, Property, |
| typename void_type< |
| decltype(decay<Property>::type::template static_query_v<T>) |
| >::type> |
| { |
| BOOST_ASIO_STATIC_CONSTEXPR(bool, is_valid = true); |
| |
| using result_type = decltype( |
| decay<Property>::type::template static_query_v<T>); |
| |
| BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = |
| noexcept(decay<Property>::type::template static_query_v<T>)); |
| |
| static BOOST_ASIO_CONSTEXPR result_type value() noexcept(is_noexcept) |
| { |
| return decay<Property>::type::template static_query_v<T>; |
| } |
| }; |
| |
| #endif // defined(BOOST_ASIO_HAS_DEDUCED_STATIC_QUERY_TRAIT) |
| |
| } // namespace detail |
| namespace traits { |
| |
| template <typename T, typename Property, typename> |
| struct static_query_default : detail::static_query_trait<T, Property> |
| { |
| }; |
| |
| template <typename T, typename Property, typename> |
| struct static_query : static_query_default<T, Property> |
| { |
| }; |
| |
| } // namespace traits |
| } // namespace asio |
| } // namespace boost |
| |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #endif // BOOST_ASIO_TRAITS_STATIC_QUERY_HPP |