1 /* Traits for Outcome 2 (C) 2018-2020 Niall Douglas <http://www.nedproductions.biz/> (8 commits) 3 File Created: March 2018 4 5 6 Boost Software License - Version 1.0 - August 17th, 2003 7 8 Permission is hereby granted, free of charge, to any person or organization 9 obtaining a copy of the software and accompanying documentation covered by 10 this license (the "Software") to use, reproduce, display, distribute, 11 execute, and transmit the Software, and to prepare derivative works of the 12 Software, and to permit third-parties to whom the Software is furnished to 13 do so, all subject to the following: 14 15 The copyright notices in the Software and this entire statement, including 16 the above license grant, this restriction and the following disclaimer, 17 must be included in all copies of the Software, in whole or in part, and 18 all derivative works of the Software, unless such copies or derivative 19 works are solely in the form of machine-executable object code generated by 20 a source language processor. 21 22 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 23 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 24 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT 25 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE 26 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, 27 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 28 DEALINGS IN THE SOFTWARE. 29 */ 30 31 #ifndef BOOST_OUTCOME_TRAIT_HPP 32 #define BOOST_OUTCOME_TRAIT_HPP 33 34 #include "config.hpp" 35 36 BOOST_OUTCOME_V2_NAMESPACE_BEGIN 37 38 namespace trait 39 { 40 /*! AWAITING HUGO JSON CONVERSION TOOL 41 SIGNATURE NOT RECOGNISED 42 */ 43 template <class R> // 44 static constexpr bool type_can_be_used_in_basic_result = // 45 (!std::is_reference<R>::value // 46 && !BOOST_OUTCOME_V2_NAMESPACE::detail::is_in_place_type_t<std::decay_t<R>>::value // 47 && !is_success_type<R> // 48 && !is_failure_type<R> // 49 && !std::is_array<R>::value // 50 && (std::is_void<R>::value || (std::is_object<R>::value // 51 && std::is_destructible<R>::value)) // 52 ); 53 54 /*! AWAITING HUGO JSON CONVERSION TOOL 55 type definition is_error_type. Potential doc page: NOT FOUND 56 */ 57 template <class E> struct is_error_type 58 { 59 static constexpr bool value = false; 60 }; 61 62 /*! AWAITING HUGO JSON CONVERSION TOOL 63 type definition is_error_type_enum. Potential doc page: NOT FOUND 64 */ 65 template <class E, class Enum> struct is_error_type_enum 66 { 67 static constexpr bool value = false; 68 }; 69 70 namespace detail 71 { 72 template <class T> using devoid = BOOST_OUTCOME_V2_NAMESPACE::detail::devoid<T>; 73 template <class T> std::add_rvalue_reference_t<devoid<T>> declval() noexcept; 74 75 // From http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4436.pdf 76 namespace detector_impl 77 { 78 template <class...> using void_t = void; 79 template <class Default, class, template <class...> class Op, class... Args> struct detector 80 { 81 static constexpr bool value = false; 82 using type = Default; 83 }; 84 template <class Default, template <class...> class Op, class... Args> struct detector<Default, void_t<Op<Args...>>, Op, Args...> 85 { 86 static constexpr bool value = true; 87 using type = Op<Args...>; 88 }; 89 } // namespace detector_impl 90 template <template <class...> class Op, class... Args> using is_detected = detector_impl::detector<void, void, Op, Args...>; 91 92 template <class Arg> using result_of_make_error_code = decltype(make_error_code(declval<Arg>())); 93 template <class Arg> using introspect_make_error_code = is_detected<result_of_make_error_code, Arg>; 94 95 template <class Arg> using result_of_make_exception_ptr = decltype(make_exception_ptr(declval<Arg>())); 96 template <class Arg> using introspect_make_exception_ptr = is_detected<result_of_make_exception_ptr, Arg>; 97 98 template <class T> struct _is_error_code_available 99 { 100 static constexpr bool value = detail::introspect_make_error_code<T>::value; 101 using type = typename detail::introspect_make_error_code<T>::type; 102 }; 103 template <class T> struct _is_exception_ptr_available 104 { 105 static constexpr bool value = detail::introspect_make_exception_ptr<T>::value; 106 using type = typename detail::introspect_make_exception_ptr<T>::type; 107 }; 108 } // namespace detail 109 110 /*! AWAITING HUGO JSON CONVERSION TOOL 111 type definition is_error_code_available. Potential doc page: NOT FOUND 112 */ 113 template <class T> struct is_error_code_available 114 { 115 static constexpr bool value = detail::_is_error_code_available<std::decay_t<T>>::value; 116 using type = typename detail::_is_error_code_available<std::decay_t<T>>::type; 117 }; 118 template <class T> constexpr bool is_error_code_available_v = detail::_is_error_code_available<std::decay_t<T>>::value; 119 120 /*! AWAITING HUGO JSON CONVERSION TOOL 121 type definition is_exception_ptr_available. Potential doc page: NOT FOUND 122 */ 123 template <class T> struct is_exception_ptr_available 124 { 125 static constexpr bool value = detail::_is_exception_ptr_available<std::decay_t<T>>::value; 126 using type = typename detail::_is_exception_ptr_available<std::decay_t<T>>::type; 127 }; 128 template <class T> constexpr bool is_exception_ptr_available_v = detail::_is_exception_ptr_available<std::decay_t<T>>::value; 129 130 131 } // namespace trait 132 133 BOOST_OUTCOME_V2_NAMESPACE_END 134 135 #endif 136