receiver.hpp 8.9 KB

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  1. //
  2. // execution/receiver.hpp
  3. // ~~~~~~~~~~~~~~~~~~~~~~
  4. //
  5. // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  6. //
  7. // Distributed under the Boost Software License, Version 1.0. (See accompanying
  8. // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  9. //
  10. #ifndef ASIO_EXECUTION_RECEIVER_HPP
  11. #define ASIO_EXECUTION_RECEIVER_HPP
  12. #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  13. # pragma once
  14. #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  15. #include "asio/detail/config.hpp"
  16. #include "asio/detail/type_traits.hpp"
  17. #include "asio/detail/variadic_templates.hpp"
  18. #include "asio/execution/set_done.hpp"
  19. #include "asio/execution/set_error.hpp"
  20. #include "asio/execution/set_value.hpp"
  21. #if defined(ASIO_HAS_STD_EXCEPTION_PTR)
  22. # include <exception>
  23. #else // defined(ASIO_HAS_STD_EXCEPTION_PTR)
  24. # include "asio/error_code.hpp"
  25. #endif // defined(ASIO_HAS_STD_EXCEPTION_PTR)
  26. #if defined(ASIO_HAS_DEDUCED_SET_DONE_FREE_TRAIT) \
  27. && defined(ASIO_HAS_DEDUCED_SET_DONE_MEMBER_TRAIT) \
  28. && defined(ASIO_HAS_DEDUCED_SET_ERROR_FREE_TRAIT) \
  29. && defined(ASIO_HAS_DEDUCED_SET_ERROR_MEMBER_TRAIT) \
  30. && defined(ASIO_HAS_DEDUCED_SET_VALUE_FREE_TRAIT) \
  31. && defined(ASIO_HAS_DEDUCED_SET_VALUE_MEMBER_TRAIT) \
  32. && defined(ASIO_HAS_DEDUCED_RECEIVER_OF_FREE_TRAIT) \
  33. && defined(ASIO_HAS_DEDUCED_RECEIVER_OF_MEMBER_TRAIT)
  34. # define ASIO_HAS_DEDUCED_EXECUTION_IS_RECEIVER_TRAIT 1
  35. #endif // defined(ASIO_HAS_DEDUCED_SET_DONE_FREE_TRAIT)
  36. // && defined(ASIO_HAS_DEDUCED_SET_DONE_MEMBER_TRAIT)
  37. // && defined(ASIO_HAS_DEDUCED_SET_ERROR_FREE_TRAIT)
  38. // && defined(ASIO_HAS_DEDUCED_SET_ERROR_MEMBER_TRAIT)
  39. // && defined(ASIO_HAS_DEDUCED_SET_VALUE_FREE_TRAIT)
  40. // && defined(ASIO_HAS_DEDUCED_SET_VALUE_MEMBER_TRAIT)
  41. // && defined(ASIO_HAS_DEDUCED_RECEIVER_OF_FREE_TRAIT)
  42. // && defined(ASIO_HAS_DEDUCED_RECEIVER_OF_MEMBER_TRAIT)
  43. #include "asio/detail/push_options.hpp"
  44. namespace asio {
  45. namespace execution {
  46. namespace detail {
  47. template <typename T, typename E>
  48. struct is_receiver_base :
  49. integral_constant<bool,
  50. is_move_constructible<typename remove_cvref<T>::type>::value
  51. && is_constructible<typename remove_cvref<T>::type, T>::value
  52. >
  53. {
  54. };
  55. } // namespace detail
  56. #if defined(ASIO_HAS_STD_EXCEPTION_PTR)
  57. # define ASIO_EXECUTION_RECEIVER_ERROR_DEFAULT = std::exception_ptr
  58. #else // defined(ASIO_HAS_STD_EXCEPTION_PTR)
  59. # define ASIO_EXECUTION_RECEIVER_ERROR_DEFAULT \
  60. = ::asio::error_code
  61. #endif // defined(ASIO_HAS_STD_EXCEPTION_PTR)
  62. /// The is_receiver trait detects whether a type T satisfies the
  63. /// execution::receiver concept.
  64. /**
  65. * Class template @c is_receiver is a type trait that is derived from @c
  66. * true_type if the type @c T meets the concept definition for a receiver for
  67. * error type @c E, otherwise @c false_type.
  68. */
  69. template <typename T, typename E ASIO_EXECUTION_RECEIVER_ERROR_DEFAULT>
  70. struct is_receiver :
  71. #if defined(GENERATING_DOCUMENTATION)
  72. integral_constant<bool, automatically_determined>
  73. #else // defined(GENERATING_DOCUMENTATION)
  74. conditional<
  75. can_set_done<typename remove_cvref<T>::type>::value
  76. && is_nothrow_set_done<typename remove_cvref<T>::type>::value
  77. && can_set_error<typename remove_cvref<T>::type, E>::value
  78. && is_nothrow_set_error<typename remove_cvref<T>::type, E>::value,
  79. detail::is_receiver_base<T, E>,
  80. false_type
  81. >::type
  82. #endif // defined(GENERATING_DOCUMENTATION)
  83. {
  84. };
  85. #if defined(ASIO_HAS_VARIABLE_TEMPLATES)
  86. template <typename T, typename E ASIO_EXECUTION_RECEIVER_ERROR_DEFAULT>
  87. ASIO_CONSTEXPR const bool is_receiver_v = is_receiver<T, E>::value;
  88. #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)
  89. #if defined(ASIO_HAS_CONCEPTS)
  90. template <typename T, typename E ASIO_EXECUTION_RECEIVER_ERROR_DEFAULT>
  91. ASIO_CONCEPT receiver = is_receiver<T, E>::value;
  92. #define ASIO_EXECUTION_RECEIVER ::asio::execution::receiver
  93. #else // defined(ASIO_HAS_CONCEPTS)
  94. #define ASIO_EXECUTION_RECEIVER typename
  95. #endif // defined(ASIO_HAS_CONCEPTS)
  96. #if defined(ASIO_HAS_VARIADIC_TEMPLATES) \
  97. || defined(GENERATING_DOCUMENTATION)
  98. /// The is_receiver_of trait detects whether a type T satisfies the
  99. /// execution::receiver_of concept for some set of value arguments.
  100. /**
  101. * Class template @c is_receiver_of is a type trait that is derived from @c
  102. * true_type if the type @c T meets the concept definition for a receiver for
  103. * value arguments @c Vs, otherwise @c false_type.
  104. */
  105. template <typename T, typename... Vs>
  106. struct is_receiver_of :
  107. #if defined(GENERATING_DOCUMENTATION)
  108. integral_constant<bool, automatically_determined>
  109. #else // defined(GENERATING_DOCUMENTATION)
  110. conditional<
  111. is_receiver<T>::value,
  112. can_set_value<typename remove_cvref<T>::type, Vs...>,
  113. false_type
  114. >::type
  115. #endif // defined(GENERATING_DOCUMENTATION)
  116. {
  117. };
  118. #if defined(ASIO_HAS_VARIABLE_TEMPLATES)
  119. template <typename T, typename... Vs>
  120. ASIO_CONSTEXPR const bool is_receiver_of_v =
  121. is_receiver_of<T, Vs...>::value;
  122. #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)
  123. #if defined(ASIO_HAS_CONCEPTS)
  124. template <typename T, typename... Vs>
  125. ASIO_CONCEPT receiver_of = is_receiver_of<T, Vs...>::value;
  126. #define ASIO_EXECUTION_RECEIVER_OF_0 \
  127. ::asio::execution::receiver_of
  128. #define ASIO_EXECUTION_RECEIVER_OF_1(v) \
  129. ::asio::execution::receiver_of<v>
  130. #else // defined(ASIO_HAS_CONCEPTS)
  131. #define ASIO_EXECUTION_RECEIVER_OF_0 typename
  132. #define ASIO_EXECUTION_RECEIVER_OF_1(v) typename
  133. #endif // defined(ASIO_HAS_CONCEPTS)
  134. #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
  135. // || defined(GENERATING_DOCUMENTATION)
  136. template <typename T, typename = void,
  137. typename = void, typename = void, typename = void, typename = void,
  138. typename = void, typename = void, typename = void, typename = void>
  139. struct is_receiver_of;
  140. template <typename T>
  141. struct is_receiver_of<T> :
  142. conditional<
  143. is_receiver<T>::value,
  144. can_set_value<typename remove_cvref<T>::type>,
  145. false_type
  146. >::type
  147. {
  148. };
  149. #define ASIO_PRIVATE_RECEIVER_OF_TRAITS_DEF(n) \
  150. template <typename T, ASIO_VARIADIC_TPARAMS(n)> \
  151. struct is_receiver_of<T, ASIO_VARIADIC_TARGS(n)> : \
  152. conditional< \
  153. conditional<true, is_receiver<T>, void>::type::value, \
  154. can_set_value< \
  155. typename remove_cvref<T>::type, \
  156. ASIO_VARIADIC_TARGS(n)>, \
  157. false_type \
  158. >::type \
  159. { \
  160. }; \
  161. /**/
  162. ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_RECEIVER_OF_TRAITS_DEF)
  163. #undef ASIO_PRIVATE_RECEIVER_OF_TRAITS_DEF
  164. #define ASIO_EXECUTION_RECEIVER_OF_0 typename
  165. #define ASIO_EXECUTION_RECEIVER_OF_1(v) typename
  166. #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
  167. // || defined(GENERATING_DOCUMENTATION)
  168. #if defined(ASIO_HAS_VARIADIC_TEMPLATES) \
  169. || defined(GENERATING_DOCUMENTATION)
  170. /// The is_nothrow_receiver_of trait detects whether a type T satisfies the
  171. /// execution::receiver_of concept for some set of value arguments, with a
  172. /// noexcept @c set_value operation.
  173. /**
  174. * Class template @c is_nothrow_receiver_of is a type trait that is derived
  175. * from @c true_type if the type @c T meets the concept definition for a
  176. * receiver for value arguments @c Vs, and the expression
  177. * <tt>execution::set_value(declval<T>(), declval<Ts>()...)</tt> is noexcept,
  178. * otherwise @c false_type.
  179. */
  180. template <typename T, typename... Vs>
  181. struct is_nothrow_receiver_of :
  182. #if defined(GENERATING_DOCUMENTATION)
  183. integral_constant<bool, automatically_determined>
  184. #else // defined(GENERATING_DOCUMENTATION)
  185. integral_constant<bool,
  186. is_receiver_of<T, Vs...>::value
  187. && is_nothrow_set_value<typename remove_cvref<T>::type, Vs...>::value
  188. >
  189. #endif // defined(GENERATING_DOCUMENTATION)
  190. {
  191. };
  192. #if defined(ASIO_HAS_VARIABLE_TEMPLATES)
  193. template <typename T, typename... Vs>
  194. ASIO_CONSTEXPR const bool is_nothrow_receiver_of_v =
  195. is_nothrow_receiver_of<T, Vs...>::value;
  196. #endif // defined(ASIO_HAS_VARIABLE_TEMPLATES)
  197. #else // defined(ASIO_HAS_VARIADIC_TEMPLATES)
  198. // || defined(GENERATING_DOCUMENTATION)
  199. template <typename T, typename = void,
  200. typename = void, typename = void, typename = void, typename = void,
  201. typename = void, typename = void, typename = void, typename = void>
  202. struct is_nothrow_receiver_of;
  203. template <typename T>
  204. struct is_nothrow_receiver_of<T> :
  205. integral_constant<bool,
  206. is_receiver_of<T>::value
  207. && is_nothrow_set_value<typename remove_cvref<T>::type>::value
  208. >
  209. {
  210. };
  211. #define ASIO_PRIVATE_NOTHROW_RECEIVER_OF_TRAITS_DEF(n) \
  212. template <typename T, ASIO_VARIADIC_TPARAMS(n)> \
  213. struct is_nothrow_receiver_of<T, ASIO_VARIADIC_TARGS(n)> : \
  214. integral_constant<bool, \
  215. is_receiver_of<T, ASIO_VARIADIC_TARGS(n)>::value \
  216. && is_nothrow_set_value<typename remove_cvref<T>::type, \
  217. ASIO_VARIADIC_TARGS(n)>::value \
  218. > \
  219. { \
  220. }; \
  221. /**/
  222. ASIO_VARIADIC_GENERATE(ASIO_PRIVATE_NOTHROW_RECEIVER_OF_TRAITS_DEF)
  223. #undef ASIO_PRIVATE_NOTHROW_RECEIVER_OF_TRAITS_DEF
  224. #endif // defined(ASIO_HAS_VARIADIC_TEMPLATES)
  225. // || defined(GENERATING_DOCUMENTATION)
  226. } // namespace execution
  227. } // namespace asio
  228. #include "asio/detail/pop_options.hpp"
  229. #endif // ASIO_EXECUTION_RECEIVER_HPP