trait.hpp 5.6 KB

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  1. /* Traits for Outcome
  2. (C) 2018-2019 Niall Douglas <http://www.nedproductions.biz/> (8 commits)
  3. File Created: March 2018
  4. Boost Software License - Version 1.0 - August 17th, 2003
  5. Permission is hereby granted, free of charge, to any person or organization
  6. obtaining a copy of the software and accompanying documentation covered by
  7. this license (the "Software") to use, reproduce, display, distribute,
  8. execute, and transmit the Software, and to prepare derivative works of the
  9. Software, and to permit third-parties to whom the Software is furnished to
  10. do so, all subject to the following:
  11. The copyright notices in the Software and this entire statement, including
  12. the above license grant, this restriction and the following disclaimer,
  13. must be included in all copies of the Software, in whole or in part, and
  14. all derivative works of the Software, unless such copies or derivative
  15. works are solely in the form of machine-executable object code generated by
  16. a source language processor.
  17. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18. IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19. FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  20. SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  21. FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  22. ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23. DEALINGS IN THE SOFTWARE.
  24. */
  25. #ifndef BOOST_OUTCOME_TRAIT_HPP
  26. #define BOOST_OUTCOME_TRAIT_HPP
  27. #include "config.hpp"
  28. BOOST_OUTCOME_V2_NAMESPACE_BEGIN
  29. namespace trait
  30. {
  31. /*! AWAITING HUGO JSON CONVERSION TOOL
  32. SIGNATURE NOT RECOGNISED
  33. */
  34. template <class R> //
  35. static constexpr bool type_can_be_used_in_basic_result = //
  36. (!std::is_reference<R>::value //
  37. && !BOOST_OUTCOME_V2_NAMESPACE::detail::is_in_place_type_t<std::decay_t<R>>::value //
  38. && !is_success_type<R> //
  39. && !is_failure_type<R> //
  40. && !std::is_array<R>::value //
  41. && (std::is_void<R>::value || (std::is_object<R>::value //
  42. && std::is_destructible<R>::value)) //
  43. );
  44. /*! AWAITING HUGO JSON CONVERSION TOOL
  45. type definition is_error_type. Potential doc page: NOT FOUND
  46. */
  47. template <class E> struct is_error_type
  48. {
  49. static constexpr bool value = false;
  50. };
  51. /*! AWAITING HUGO JSON CONVERSION TOOL
  52. type definition is_error_type_enum. Potential doc page: NOT FOUND
  53. */
  54. template <class E, class Enum> struct is_error_type_enum
  55. {
  56. static constexpr bool value = false;
  57. };
  58. namespace detail
  59. {
  60. template <class T> using devoid = BOOST_OUTCOME_V2_NAMESPACE::detail::devoid<T>;
  61. template <class T> std::add_rvalue_reference_t<devoid<T>> declval() noexcept;
  62. // From http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4436.pdf
  63. namespace detector_impl
  64. {
  65. template <class...> using void_t = void;
  66. template <class Default, class, template <class...> class Op, class... Args> struct detector
  67. {
  68. static constexpr bool value = false;
  69. using type = Default;
  70. };
  71. template <class Default, template <class...> class Op, class... Args> struct detector<Default, void_t<Op<Args...>>, Op, Args...>
  72. {
  73. static constexpr bool value = true;
  74. using type = Op<Args...>;
  75. };
  76. } // namespace detector_impl
  77. template <template <class...> class Op, class... Args> using is_detected = detector_impl::detector<void, void, Op, Args...>;
  78. template <class Arg> using result_of_make_error_code = decltype(make_error_code(declval<Arg>()));
  79. template <class Arg> using introspect_make_error_code = is_detected<result_of_make_error_code, Arg>;
  80. template <class Arg> using result_of_make_exception_ptr = decltype(make_exception_ptr(declval<Arg>()));
  81. template <class Arg> using introspect_make_exception_ptr = is_detected<result_of_make_exception_ptr, Arg>;
  82. template <class T> struct _is_error_code_available
  83. {
  84. static constexpr bool value = detail::introspect_make_error_code<T>::value;
  85. using type = typename detail::introspect_make_error_code<T>::type;
  86. };
  87. template <class T> struct _is_exception_ptr_available
  88. {
  89. static constexpr bool value = detail::introspect_make_exception_ptr<T>::value;
  90. using type = typename detail::introspect_make_exception_ptr<T>::type;
  91. };
  92. } // namespace detail
  93. /*! AWAITING HUGO JSON CONVERSION TOOL
  94. type definition is_error_code_available. Potential doc page: NOT FOUND
  95. */
  96. template <class T> struct is_error_code_available
  97. {
  98. static constexpr bool value = detail::_is_error_code_available<std::decay_t<T>>::value;
  99. using type = typename detail::_is_error_code_available<std::decay_t<T>>::type;
  100. };
  101. template <class T> constexpr bool is_error_code_available_v = detail::_is_error_code_available<std::decay_t<T>>::value;
  102. /*! AWAITING HUGO JSON CONVERSION TOOL
  103. type definition is_exception_ptr_available. Potential doc page: NOT FOUND
  104. */
  105. template <class T> struct is_exception_ptr_available
  106. {
  107. static constexpr bool value = detail::_is_exception_ptr_available<std::decay_t<T>>::value;
  108. using type = typename detail::_is_exception_ptr_available<std::decay_t<T>>::type;
  109. };
  110. template <class T> constexpr bool is_exception_ptr_available_v = detail::_is_exception_ptr_available<std::decay_t<T>>::value;
  111. } // namespace trait
  112. BOOST_OUTCOME_V2_NAMESPACE_END
  113. #endif