status_result.hpp 8.1 KB

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  1. /* A very simple result type
  2. (C) 2018-2023 Niall Douglas <http://www.nedproductions.biz/> (11 commits)
  3. File Created: Apr 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_EXPERIMENTAL_STATUS_RESULT_HPP
  26. #define BOOST_OUTCOME_EXPERIMENTAL_STATUS_RESULT_HPP
  27. #include "../basic_result.hpp"
  28. #include "../policy/fail_to_compile_observers.hpp"
  29. #if __PCPP_ALWAYS_TRUE__
  30. #include "status-code/status-code/system_error2.hpp"
  31. #elif !BOOST_OUTCOME_USE_SYSTEM_STATUS_CODE && __has_include("status-code/status-code/system_error2.hpp")
  32. #include "status-code/status-code/system_error2.hpp"
  33. #else
  34. #include <status-code/system_error2.hpp>
  35. #endif
  36. BOOST_OUTCOME_V2_NAMESPACE_EXPORT_BEGIN
  37. namespace trait
  38. {
  39. namespace detail
  40. {
  41. // Shortcut this for lower build impact. Used to tell outcome's converting constructors
  42. // that they can do E => EC or E => EP as necessary.
  43. template <class DomainType> struct _is_error_code_available<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<DomainType>>
  44. {
  45. static constexpr bool value = true;
  46. using type = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<DomainType>;
  47. };
  48. template <class DomainType> struct _is_error_code_available<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errored_status_code<DomainType>>
  49. {
  50. static constexpr bool value = true;
  51. using type = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errored_status_code<DomainType>;
  52. };
  53. } // namespace detail
  54. #if 0 // Do NOT enable weakened implicit construction for these types
  55. template <class DomainType> struct is_error_type<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<DomainType>>
  56. {
  57. static constexpr bool value = true;
  58. };
  59. template <> struct is_error_type<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errc>
  60. {
  61. static constexpr bool value = true;
  62. };
  63. template <class DomainType, class Enum> struct is_error_type_enum<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<DomainType>, Enum>
  64. {
  65. static constexpr bool value = boost::system::is_error_condition_enum<Enum>::value;
  66. };
  67. #endif
  68. template <class DomainType> struct is_move_bitcopying<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<DomainType>>
  69. {
  70. static constexpr bool value = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::traits::is_move_bitcopying<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<DomainType>>::value;
  71. };
  72. template <class DomainType> struct is_move_bitcopying<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errored_status_code<DomainType>>
  73. {
  74. static constexpr bool value = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::traits::is_move_bitcopying<BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errored_status_code<DomainType>>::value;
  75. };
  76. } // namespace trait
  77. namespace detail
  78. {
  79. // Customise _set_error_is_errno
  80. template <class State> constexpr inline void _set_error_is_errno(State &state, const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::generic_code & /*unused*/)
  81. {
  82. state._status.set_have_error_is_errno(true);
  83. }
  84. #ifndef BOOST_OUTCOME_SYSTEM_ERROR2_NOT_POSIX
  85. template <class State> constexpr inline void _set_error_is_errno(State &state, const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::posix_code & /*unused*/)
  86. {
  87. state._status.set_have_error_is_errno(true);
  88. }
  89. #endif
  90. template <class State> constexpr inline void _set_error_is_errno(State &state, const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errc & /*unused*/)
  91. {
  92. state._status.set_have_error_is_errno(true);
  93. }
  94. } // namespace detail
  95. namespace experimental
  96. {
  97. using namespace BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE;
  98. using BOOST_OUTCOME_V2_NAMESPACE::failure;
  99. using BOOST_OUTCOME_V2_NAMESPACE::success;
  100. namespace policy
  101. {
  102. using namespace BOOST_OUTCOME_V2_NAMESPACE::policy;
  103. template <class T, class EC, class E> struct status_code_throw
  104. {
  105. static_assert(!std::is_same<T, T>::value,
  106. "policy::status_code_throw not specialised for these types, did you use status_result<T, status_code<DomainType>, E>?");
  107. };
  108. template <class T, class DomainType> struct status_code_throw<T, status_code<DomainType>, void> : base
  109. {
  110. using _base = base;
  111. template <class Impl> static constexpr void wide_value_check(Impl &&self)
  112. {
  113. if(!base::_has_value(static_cast<Impl &&>(self)))
  114. {
  115. if(base::_has_error(static_cast<Impl &&>(self)))
  116. {
  117. #ifndef BOOST_NO_EXCEPTIONS
  118. base::_error(static_cast<Impl &&>(self)).throw_exception();
  119. #else
  120. BOOST_OUTCOME_THROW_EXCEPTION("wide value check failed");
  121. #endif
  122. }
  123. }
  124. }
  125. template <class Impl> static constexpr void wide_error_check(Impl &&self) { _base::narrow_error_check(static_cast<Impl &&>(self)); }
  126. };
  127. template <class T, class DomainType>
  128. struct status_code_throw<T, errored_status_code<DomainType>, void> : status_code_throw<T, status_code<DomainType>, void>
  129. {
  130. status_code_throw() = default;
  131. using status_code_throw<T, status_code<DomainType>, void>::status_code_throw;
  132. };
  133. template <class T, class EC>
  134. using default_status_result_policy = std::conditional_t< //
  135. std::is_void<EC>::value, //
  136. BOOST_OUTCOME_V2_NAMESPACE::policy::terminate, //
  137. std::conditional_t<is_status_code<EC>::value || is_errored_status_code<EC>::value, //
  138. status_code_throw<T, EC, void>, //
  139. BOOST_OUTCOME_V2_NAMESPACE::policy::fail_to_compile_observers //
  140. >>;
  141. } // namespace policy
  142. /*! AWAITING HUGO JSON CONVERSION TOOL
  143. SIGNATURE NOT RECOGNISED
  144. */
  145. template <class R, class S = errored_status_code<erased<typename system_code::value_type>>,
  146. class NoValuePolicy = policy::default_status_result_policy<R, S>> //
  147. using status_result = basic_result<R, S, NoValuePolicy>;
  148. /*! AWAITING HUGO JSON CONVERSION TOOL
  149. SIGNATURE NOT RECOGNISED
  150. */
  151. BOOST_OUTCOME_TEMPLATE(class R, class S, class NoValuePolicy)
  152. BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(std::is_copy_constructible<R>::value && (is_status_code<S>::value || is_errored_status_code<S>::value)))
  153. inline basic_result<R, S, NoValuePolicy> clone(const basic_result<R, S, NoValuePolicy> &v)
  154. {
  155. if(v)
  156. {
  157. return success_type<R>(v.assume_value());
  158. }
  159. return failure_type<S>(v.assume_error().clone(), hooks::spare_storage(&v));
  160. }
  161. /*! AWAITING HUGO JSON CONVERSION TOOL
  162. SIGNATURE NOT RECOGNISED
  163. */
  164. BOOST_OUTCOME_TEMPLATE(class S, class NoValuePolicy)
  165. BOOST_OUTCOME_TREQUIRES(BOOST_OUTCOME_TPRED(is_status_code<S>::value || is_errored_status_code<S>::value))
  166. inline basic_result<void, S, NoValuePolicy> clone(const basic_result<void, S, NoValuePolicy> &v)
  167. {
  168. if(v)
  169. {
  170. return success_type<void>();
  171. }
  172. return failure_type<S>(v.assume_error().clone(), hooks::spare_storage(&v));
  173. }
  174. } // namespace experimental
  175. BOOST_OUTCOME_V2_NAMESPACE_END
  176. #endif