ceph/src/boost/boost/asio/execution/set_value.hpp

   1 //
   2 // execution/set_value.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2020 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
  11 #ifndef BOOST_ASIO_EXECUTION_SET_VALUE_HPP
  12 #define BOOST_ASIO_EXECUTION_SET_VALUE_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19 #include <boost/asio/detail/type_traits.hpp>
  20 #include <boost/asio/detail/variadic_templates.hpp>
  21 #include <boost/asio/traits/set_value_member.hpp>
  22 #include <boost/asio/traits/set_value_free.hpp>
  23
  24 #include <boost/asio/detail/push_options.hpp>
  25
  26 #if defined(GENERATING_DOCUMENTATION)
  27
  28 namespace boost {
  29 namespace asio {
  30 namespace execution {
  31
  32 /// A customisation point that delivers a value to a receiver.
  33 /**
  34  * The name <tt>execution::set_value</tt> denotes a customisation point object.
  35  * The expression <tt>execution::set_value(R, Vs...)</tt> for some
  36  * subexpressions <tt>R</tt> and <tt>Vs...</tt> is expression-equivalent to:
  37  *
  38  * @li <tt>R.set_value(Vs...)</tt>, if that expression is valid. If the
  39  *   function selected does not send the value(s) <tt>Vs...</tt> to the receiver
  40  *   <tt>R</tt>'s value channel, the program is ill-formed with no diagnostic
  41  *   required.
  42  *
  43  * @li Otherwise, <tt>set_value(R, Vs...)</tt>, if that expression is valid,
  44  *   with overload resolution performed in a context that includes the
  45  *   declaration <tt>void set_value();</tt> and that does not include a
  46  *   declaration of <tt>execution::set_value</tt>. If the function selected by
  47  *   overload resolution does not send the value(s) <tt>Vs...</tt> to the
  48  *   receiver <tt>R</tt>'s value channel, the program is ill-formed with no
  49  *   diagnostic required.
  50  *
  51  * @li Otherwise, <tt>execution::set_value(R, Vs...)</tt> is ill-formed.
  52  */
  53 inline constexpr unspecified set_value = unspecified;
  54
  55 /// A type trait that determines whether a @c set_value expression is
  56 /// well-formed.
  57 /**
  58  * Class template @c can_set_value is a trait that is derived from
  59  * @c true_type if the expression <tt>execution::set_value(std::declval<R>(),
  60  * std::declval<Vs>()...)</tt> is well formed; otherwise @c false_type.
  61  */
  62 template <typename R, typename... Vs>
  63 struct can_set_value :
  64   integral_constant<bool, automatically_determined>
  65 {
  66 };
  67
  68 } // namespace execution
  69 } // namespace asio
  70 } // namespace boost
  71
  72 #else // defined(GENERATING_DOCUMENTATION)
  73
  74 namespace asio_execution_set_value_fn {
  75
  76 using boost::asio::decay;
  77 using boost::asio::declval;
  78 using boost::asio::enable_if;
  79 using boost::asio::traits::set_value_free;
  80 using boost::asio::traits::set_value_member;
  81
  82 void set_value();
  83
  84 enum overload_type
  85 {
  86   call_member,
  87   call_free,
  88   ill_formed
  89 };
  90
  91 template <typename R, typename Vs, typename = void>
  92 struct call_traits
  93 {
  94   BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed);
  95   BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
  96   typedef void result_type;
  97 };
  98
  99 template <typename R, typename Vs>
 100 struct call_traits<R, Vs,
 101   typename enable_if<
 102     (
 103       set_value_member<R, Vs>::is_valid
 104     )
 105   >::type> :
 106   set_value_member<R, Vs>
 107 {
 108   BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
 109 };
 110
 111 template <typename R, typename Vs>
 112 struct call_traits<R, Vs,
 113   typename enable_if<
 114     (
 115       !set_value_member<R, Vs>::is_valid
 116       &&
 117       set_value_free<R, Vs>::is_valid
 118     )
 119   >::type> :
 120   set_value_free<R, Vs>
 121 {
 122   BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
 123 };
 124
 125 struct impl
 126 {
 127 #if defined(BOOST_ASIO_HAS_MOVE)
 128
 129 #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 130
 131   template <typename R, typename... Vs>
 132   BOOST_ASIO_CONSTEXPR typename enable_if<
 133     call_traits<R, void(Vs...)>::overload == call_member,
 134     typename call_traits<R, void(Vs...)>::result_type
 135   >::type
 136   operator()(R&& r, Vs&&... v) const
 137     BOOST_ASIO_NOEXCEPT_IF((
 138       call_traits<R, void(Vs...)>::is_noexcept))
 139   {
 140     return BOOST_ASIO_MOVE_CAST(R)(r).set_value(BOOST_ASIO_MOVE_CAST(Vs)(v)...);
 141   }
 142
 143   template <typename R, typename... Vs>
 144   BOOST_ASIO_CONSTEXPR typename enable_if<
 145     call_traits<R, void(Vs...)>::overload == call_free,
 146     typename call_traits<R, void(Vs...)>::result_type
 147   >::type
 148   operator()(R&& r, Vs&&... v) const
 149     BOOST_ASIO_NOEXCEPT_IF((
 150       call_traits<R, void(Vs...)>::is_noexcept))
 151   {
 152     return set_value(BOOST_ASIO_MOVE_CAST(R)(r),
 153         BOOST_ASIO_MOVE_CAST(Vs)(v)...);
 154   }
 155
 156 #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 157
 158   template <typename R>
 159   BOOST_ASIO_CONSTEXPR typename enable_if<
 160     call_traits<R, void()>::overload == call_member,
 161     typename call_traits<R, void()>::result_type
 162   >::type
 163   operator()(R&& r) const
 164     BOOST_ASIO_NOEXCEPT_IF((
 165       call_traits<R, void()>::is_noexcept))
 166   {
 167     return BOOST_ASIO_MOVE_CAST(R)(r).set_value();
 168   }
 169
 170   template <typename R>
 171   BOOST_ASIO_CONSTEXPR typename enable_if<
 172     call_traits<R, void()>::overload == call_free,
 173     typename call_traits<R, void()>::result_type
 174   >::type
 175   operator()(R&& r) const
 176     BOOST_ASIO_NOEXCEPT_IF((
 177       call_traits<R, void()>::is_noexcept))
 178   {
 179     return set_value(BOOST_ASIO_MOVE_CAST(R)(r));
 180   }
 181
 182 #define BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF(n) \
 183   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 184   BOOST_ASIO_CONSTEXPR typename enable_if< \
 185     call_traits<R, \
 186       void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_member, \
 187     typename call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
 188   >::type \
 189   operator()(R&& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
 190     BOOST_ASIO_NOEXCEPT_IF(( \
 191       call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
 192   { \
 193     return BOOST_ASIO_MOVE_CAST(R)(r).set_value( \
 194         BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
 195   } \
 196   \
 197   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 198   BOOST_ASIO_CONSTEXPR typename enable_if< \
 199     call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_free, \
 200     typename call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
 201   >::type \
 202   operator()(R&& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
 203     BOOST_ASIO_NOEXCEPT_IF(( \
 204       call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
 205   { \
 206     return set_value(BOOST_ASIO_MOVE_CAST(R)(r), \
 207         BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
 208   } \
 209   /**/
 210 BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF)
 211 #undef BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF
 212
 213 #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 214
 215 #else // defined(BOOST_ASIO_HAS_MOVE)
 216
 217 #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 218
 219   template <typename R, typename... Vs>
 220   BOOST_ASIO_CONSTEXPR typename enable_if<
 221     call_traits<R&, void(const Vs&...)>::overload == call_member,
 222     typename call_traits<R&, void(const Vs&...)>::result_type
 223   >::type
 224   operator()(R& r, const Vs&... v) const
 225     BOOST_ASIO_NOEXCEPT_IF((
 226       call_traits<R&, void(const Vs&...)>::is_noexcept))
 227   {
 228     return r.set_value(v...);
 229   }
 230
 231   template <typename R, typename... Vs>
 232   BOOST_ASIO_CONSTEXPR typename enable_if<
 233     call_traits<const R&, void(const Vs&...)>::overload == call_member,
 234     typename call_traits<const R&, void(const Vs&...)>::result_type
 235   >::type
 236   operator()(const R& r, const Vs&... v) const
 237     BOOST_ASIO_NOEXCEPT_IF((
 238       call_traits<const R&, void(const Vs&...)>::is_noexcept))
 239   {
 240     return r.set_value(v...);
 241   }
 242
 243   template <typename R, typename... Vs>
 244   BOOST_ASIO_CONSTEXPR typename enable_if<
 245     call_traits<R&, void(const Vs&...)>::overload == call_free,
 246     typename call_traits<R&, void(const Vs&...)>::result_type
 247   >::type
 248   operator()(R& r, const Vs&... v) const
 249     BOOST_ASIO_NOEXCEPT_IF((
 250       call_traits<R&, void(const Vs&...)>::is_noexcept))
 251   {
 252     return set_value(r, v...);
 253   }
 254
 255   template <typename R, typename... Vs>
 256   BOOST_ASIO_CONSTEXPR typename enable_if<
 257     call_traits<const R&, void(const Vs&...)>::overload == call_free,
 258     typename call_traits<const R&, void(const Vs&...)>::result_type
 259   >::type
 260   operator()(const R& r, const Vs&... v) const
 261     BOOST_ASIO_NOEXCEPT_IF((
 262       call_traits<const R&, void(const Vs&...)>::is_noexcept))
 263   {
 264     return set_value(r, v...);
 265   }
 266
 267 #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 268
 269   template <typename R>
 270   BOOST_ASIO_CONSTEXPR typename enable_if<
 271     call_traits<R&, void()>::overload == call_member,
 272     typename call_traits<R&, void()>::result_type
 273   >::type
 274   operator()(R& r) const
 275     BOOST_ASIO_NOEXCEPT_IF((
 276       call_traits<R&, void()>::is_noexcept))
 277   {
 278     return r.set_value();
 279   }
 280
 281   template <typename R>
 282   BOOST_ASIO_CONSTEXPR typename enable_if<
 283     call_traits<const R&, void()>::overload == call_member,
 284     typename call_traits<const R&, void()>::result_type
 285   >::type
 286   operator()(const R& r) const
 287     BOOST_ASIO_NOEXCEPT_IF((
 288       call_traits<const R&, void()>::is_noexcept))
 289   {
 290     return r.set_value();
 291   }
 292
 293   template <typename R>
 294   BOOST_ASIO_CONSTEXPR typename enable_if<
 295     call_traits<R&, void()>::overload == call_free,
 296     typename call_traits<R&, void()>::result_type
 297   >::type
 298   operator()(R& r) const
 299     BOOST_ASIO_NOEXCEPT_IF((
 300       call_traits<R&, void()>::is_noexcept))
 301   {
 302     return set_value(r);
 303   }
 304
 305   template <typename R>
 306   BOOST_ASIO_CONSTEXPR typename enable_if<
 307     call_traits<const R&, void()>::overload == call_free,
 308     typename call_traits<const R&, void()>::result_type
 309   >::type
 310   operator()(const R& r) const
 311     BOOST_ASIO_NOEXCEPT_IF((
 312       call_traits<const R&, void()>::is_noexcept))
 313   {
 314     return set_value(r);
 315   }
 316
 317 #define BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF(n) \
 318   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 319   BOOST_ASIO_CONSTEXPR typename enable_if< \
 320     call_traits<R&, \
 321       void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_member, \
 322     typename call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
 323   >::type \
 324   operator()(R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
 325     BOOST_ASIO_NOEXCEPT_IF(( \
 326       call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
 327   { \
 328     return r.set_value(BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
 329   } \
 330   \
 331   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 332   BOOST_ASIO_CONSTEXPR typename enable_if< \
 333     call_traits<const R&, \
 334       void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_member, \
 335     typename call_traits<const R&, \
 336       void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
 337   >::type \
 338   operator()(const R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
 339     BOOST_ASIO_NOEXCEPT_IF(( \
 340       call_traits<const R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
 341   { \
 342     return r.set_value(BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
 343   } \
 344   \
 345   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 346   BOOST_ASIO_CONSTEXPR typename enable_if< \
 347     call_traits<R&, \
 348       void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_free, \
 349     typename call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
 350   >::type \
 351   operator()(R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
 352     BOOST_ASIO_NOEXCEPT_IF(( \
 353       call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
 354   { \
 355     return set_value(r, BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
 356   } \
 357   \
 358   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 359   BOOST_ASIO_CONSTEXPR typename enable_if< \
 360     call_traits<const R&, \
 361       void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_free, \
 362     typename call_traits<const R&, \
 363       void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
 364   >::type \
 365   operator()(const R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
 366     BOOST_ASIO_NOEXCEPT_IF(( \
 367       call_traits<const R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
 368   { \
 369     return set_value(r, BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
 370   } \
 371   /**/
 372 BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF)
 373 #undef BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF
 374
 375 #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 376
 377 #endif // defined(BOOST_ASIO_HAS_MOVE)
 378 };
 379
 380 template <typename T = impl>
 381 struct static_instance
 382 {
 383   static const T instance;
 384 };
 385
 386 template <typename T>
 387 const T static_instance<T>::instance = {};
 388
 389 } // namespace asio_execution_set_value_fn
 390 namespace boost {
 391 namespace asio {
 392 namespace execution {
 393 namespace {
 394
 395 static BOOST_ASIO_CONSTEXPR const asio_execution_set_value_fn::impl&
 396   set_value = asio_execution_set_value_fn::static_instance<>::instance;
 397
 398 } // namespace
 399
 400 #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 401
 402 template <typename R, typename... Vs>
 403 struct can_set_value :
 404   integral_constant<bool,
 405     asio_execution_set_value_fn::call_traits<R, void(Vs...)>::overload !=
 406       asio_execution_set_value_fn::ill_formed>
 407 {
 408 };
 409
 410 #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
 411
 412 template <typename R, typename... Vs>
 413 constexpr bool can_set_value_v = can_set_value<R, Vs...>::value;
 414
 415 #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
 416
 417 template <typename R, typename... Vs>
 418 struct is_nothrow_set_value :
 419   integral_constant<bool,
 420     asio_execution_set_value_fn::call_traits<R, void(Vs...)>::is_noexcept>
 421 {
 422 };
 423
 424 #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
 425
 426 template <typename R, typename... Vs>
 427 constexpr bool is_nothrow_set_value_v
 428   = is_nothrow_set_value<R, Vs...>::value;
 429
 430 #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
 431
 432 #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 433
 434 template <typename R, typename = void,
 435     typename = void, typename = void, typename = void, typename = void,
 436     typename = void, typename = void, typename = void, typename = void>
 437 struct can_set_value;
 438
 439 template <typename R, typename = void,
 440     typename = void, typename = void, typename = void, typename = void,
 441     typename = void, typename = void, typename = void, typename = void>
 442 struct is_nothrow_set_value;
 443
 444 template <typename R>
 445 struct can_set_value<R> :
 446   integral_constant<bool,
 447     asio_execution_set_value_fn::call_traits<R, void()>::overload !=
 448       asio_execution_set_value_fn::ill_formed>
 449 {
 450 };
 451
 452 template <typename R>
 453 struct is_nothrow_set_value<R> :
 454   integral_constant<bool,
 455     asio_execution_set_value_fn::call_traits<R, void()>::is_noexcept>
 456 {
 457 };
 458
 459 #define BOOST_ASIO_PRIVATE_SET_VALUE_TRAITS_DEF(n) \
 460   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 461   struct can_set_value<R, BOOST_ASIO_VARIADIC_TARGS(n)> : \
 462     integral_constant<bool, \
 463       asio_execution_set_value_fn::call_traits<R, \
 464         void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload != \
 465           asio_execution_set_value_fn::ill_formed> \
 466   { \
 467   }; \
 468   \
 469   template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
 470   struct is_nothrow_set_value<R, BOOST_ASIO_VARIADIC_TARGS(n)> : \
 471     integral_constant<bool, \
 472       asio_execution_set_value_fn::call_traits<R, \
 473         void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept> \
 474   { \
 475   }; \
 476   /**/
 477 BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_SET_VALUE_TRAITS_DEF)
 478 #undef BOOST_ASIO_PRIVATE_SET_VALUE_TRAITS_DEF
 479
 480 #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
 481
 482 } // namespace execution
 483 } // namespace asio
 484 } // namespace boost
 485
 486 #endif // defined(GENERATING_DOCUMENTATION)
 487
 488 #include <boost/asio/detail/pop_options.hpp>
 489
 490 #endif // BOOST_ASIO_EXECUTION_SET_VALUE_HPP