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- //
- // execution/set_value.hpp
- // ~~~~~~~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
- //
- // Distributed under the Boost Software License, Version 1.0. (See accompanying
- // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- //
- #ifndef BOOST_ASIO_EXECUTION_SET_VALUE_HPP
- #define BOOST_ASIO_EXECUTION_SET_VALUE_HPP
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
- #include <boost/asio/detail/config.hpp>
- #include <boost/asio/detail/type_traits.hpp>
- #include <boost/asio/detail/variadic_templates.hpp>
- #include <boost/asio/traits/set_value_member.hpp>
- #include <boost/asio/traits/set_value_free.hpp>
- #include <boost/asio/detail/push_options.hpp>
- #if defined(GENERATING_DOCUMENTATION)
- namespace boost {
- namespace asio {
- namespace execution {
- /// A customisation point that delivers a value to a receiver.
- /**
- * The name <tt>execution::set_value</tt> denotes a customisation point object.
- * The expression <tt>execution::set_value(R, Vs...)</tt> for some
- * subexpressions <tt>R</tt> and <tt>Vs...</tt> is expression-equivalent to:
- *
- * @li <tt>R.set_value(Vs...)</tt>, if that expression is valid. If the
- * function selected does not send the value(s) <tt>Vs...</tt> to the receiver
- * <tt>R</tt>'s value channel, the program is ill-formed with no diagnostic
- * required.
- *
- * @li Otherwise, <tt>set_value(R, Vs...)</tt>, if that expression is valid,
- * with overload resolution performed in a context that includes the
- * declaration <tt>void set_value();</tt> and that does not include a
- * declaration of <tt>execution::set_value</tt>. If the function selected by
- * overload resolution does not send the value(s) <tt>Vs...</tt> to the
- * receiver <tt>R</tt>'s value channel, the program is ill-formed with no
- * diagnostic required.
- *
- * @li Otherwise, <tt>execution::set_value(R, Vs...)</tt> is ill-formed.
- */
- inline constexpr unspecified set_value = unspecified;
- /// A type trait that determines whether a @c set_value expression is
- /// well-formed.
- /**
- * Class template @c can_set_value is a trait that is derived from
- * @c true_type if the expression <tt>execution::set_value(std::declval<R>(),
- * std::declval<Vs>()...)</tt> is well formed; otherwise @c false_type.
- */
- template <typename R, typename... Vs>
- struct can_set_value :
- integral_constant<bool, automatically_determined>
- {
- };
- } // namespace execution
- } // namespace asio
- } // namespace boost
- #else // defined(GENERATING_DOCUMENTATION)
- namespace asio_execution_set_value_fn {
- using boost::asio::decay;
- using boost::asio::declval;
- using boost::asio::enable_if;
- using boost::asio::traits::set_value_free;
- using boost::asio::traits::set_value_member;
- void set_value();
- enum overload_type
- {
- call_member,
- call_free,
- ill_formed
- };
- template <typename R, typename Vs, typename = void, typename = void>
- struct call_traits
- {
- BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = ill_formed);
- BOOST_ASIO_STATIC_CONSTEXPR(bool, is_noexcept = false);
- typedef void result_type;
- };
- template <typename R, typename Vs>
- struct call_traits<R, Vs,
- typename enable_if<
- set_value_member<R, Vs>::is_valid
- >::type> :
- set_value_member<R, Vs>
- {
- BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
- };
- template <typename R, typename Vs>
- struct call_traits<R, Vs,
- typename enable_if<
- !set_value_member<R, Vs>::is_valid
- >::type,
- typename enable_if<
- set_value_free<R, Vs>::is_valid
- >::type> :
- set_value_free<R, Vs>
- {
- BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
- };
- struct impl
- {
- #if defined(BOOST_ASIO_HAS_MOVE)
- #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- template <typename R, typename... Vs>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R, void(Vs...)>::overload == call_member,
- typename call_traits<R, void(Vs...)>::result_type
- >::type
- operator()(R&& r, Vs&&... v) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R, void(Vs...)>::is_noexcept))
- {
- return BOOST_ASIO_MOVE_CAST(R)(r).set_value(BOOST_ASIO_MOVE_CAST(Vs)(v)...);
- }
- template <typename R, typename... Vs>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R, void(Vs...)>::overload == call_free,
- typename call_traits<R, void(Vs...)>::result_type
- >::type
- operator()(R&& r, Vs&&... v) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R, void(Vs...)>::is_noexcept))
- {
- return set_value(BOOST_ASIO_MOVE_CAST(R)(r),
- BOOST_ASIO_MOVE_CAST(Vs)(v)...);
- }
- #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- template <typename R>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R, void()>::overload == call_member,
- typename call_traits<R, void()>::result_type
- >::type
- operator()(R&& r) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R, void()>::is_noexcept))
- {
- return BOOST_ASIO_MOVE_CAST(R)(r).set_value();
- }
- template <typename R>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R, void()>::overload == call_free,
- typename call_traits<R, void()>::result_type
- >::type
- operator()(R&& r) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R, void()>::is_noexcept))
- {
- return set_value(BOOST_ASIO_MOVE_CAST(R)(r));
- }
- #define BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF(n) \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- BOOST_ASIO_CONSTEXPR typename enable_if< \
- call_traits<R, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_member, \
- typename call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
- >::type \
- operator()(R&& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
- BOOST_ASIO_NOEXCEPT_IF(( \
- call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
- { \
- return BOOST_ASIO_MOVE_CAST(R)(r).set_value( \
- BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- BOOST_ASIO_CONSTEXPR typename enable_if< \
- call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_free, \
- typename call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
- >::type \
- operator()(R&& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
- BOOST_ASIO_NOEXCEPT_IF(( \
- call_traits<R, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
- { \
- return set_value(BOOST_ASIO_MOVE_CAST(R)(r), \
- BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- /**/
- BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF)
- #undef BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF
- #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- #else // defined(BOOST_ASIO_HAS_MOVE)
- #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- template <typename R, typename... Vs>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R&, void(const Vs&...)>::overload == call_member,
- typename call_traits<R&, void(const Vs&...)>::result_type
- >::type
- operator()(R& r, const Vs&... v) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R&, void(const Vs&...)>::is_noexcept))
- {
- return r.set_value(v...);
- }
- template <typename R, typename... Vs>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<const R&, void(const Vs&...)>::overload == call_member,
- typename call_traits<const R&, void(const Vs&...)>::result_type
- >::type
- operator()(const R& r, const Vs&... v) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<const R&, void(const Vs&...)>::is_noexcept))
- {
- return r.set_value(v...);
- }
- template <typename R, typename... Vs>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R&, void(const Vs&...)>::overload == call_free,
- typename call_traits<R&, void(const Vs&...)>::result_type
- >::type
- operator()(R& r, const Vs&... v) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R&, void(const Vs&...)>::is_noexcept))
- {
- return set_value(r, v...);
- }
- template <typename R, typename... Vs>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<const R&, void(const Vs&...)>::overload == call_free,
- typename call_traits<const R&, void(const Vs&...)>::result_type
- >::type
- operator()(const R& r, const Vs&... v) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<const R&, void(const Vs&...)>::is_noexcept))
- {
- return set_value(r, v...);
- }
- #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- template <typename R>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R&, void()>::overload == call_member,
- typename call_traits<R&, void()>::result_type
- >::type
- operator()(R& r) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R&, void()>::is_noexcept))
- {
- return r.set_value();
- }
- template <typename R>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<const R&, void()>::overload == call_member,
- typename call_traits<const R&, void()>::result_type
- >::type
- operator()(const R& r) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<const R&, void()>::is_noexcept))
- {
- return r.set_value();
- }
- template <typename R>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R&, void()>::overload == call_free,
- typename call_traits<R&, void()>::result_type
- >::type
- operator()(R& r) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R&, void()>::is_noexcept))
- {
- return set_value(r);
- }
- template <typename R>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<const R&, void()>::overload == call_free,
- typename call_traits<const R&, void()>::result_type
- >::type
- operator()(const R& r) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<const R&, void()>::is_noexcept))
- {
- return set_value(r);
- }
- #define BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF(n) \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- BOOST_ASIO_CONSTEXPR typename enable_if< \
- call_traits<R&, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_member, \
- typename call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
- >::type \
- operator()(R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
- BOOST_ASIO_NOEXCEPT_IF(( \
- call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
- { \
- return r.set_value(BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- BOOST_ASIO_CONSTEXPR typename enable_if< \
- call_traits<const R&, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_member, \
- typename call_traits<const R&, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
- >::type \
- operator()(const R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
- BOOST_ASIO_NOEXCEPT_IF(( \
- call_traits<const R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
- { \
- return r.set_value(BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- BOOST_ASIO_CONSTEXPR typename enable_if< \
- call_traits<R&, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_free, \
- typename call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
- >::type \
- operator()(R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
- BOOST_ASIO_NOEXCEPT_IF(( \
- call_traits<R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
- { \
- return set_value(r, BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- BOOST_ASIO_CONSTEXPR typename enable_if< \
- call_traits<const R&, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload == call_free, \
- typename call_traits<const R&, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::result_type \
- >::type \
- operator()(const R& r, BOOST_ASIO_VARIADIC_MOVE_PARAMS(n)) const \
- BOOST_ASIO_NOEXCEPT_IF(( \
- call_traits<const R&, void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept)) \
- { \
- return set_value(r, BOOST_ASIO_VARIADIC_MOVE_ARGS(n)); \
- } \
- /**/
- BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF)
- #undef BOOST_ASIO_PRIVATE_SET_VALUE_CALL_DEF
- #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- #endif // defined(BOOST_ASIO_HAS_MOVE)
- };
- template <typename T = impl>
- struct static_instance
- {
- static const T instance;
- };
- template <typename T>
- const T static_instance<T>::instance = {};
- } // namespace asio_execution_set_value_fn
- namespace boost {
- namespace asio {
- namespace execution {
- namespace {
- static BOOST_ASIO_CONSTEXPR const asio_execution_set_value_fn::impl&
- set_value = asio_execution_set_value_fn::static_instance<>::instance;
- } // namespace
- #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- template <typename R, typename... Vs>
- struct can_set_value :
- integral_constant<bool,
- asio_execution_set_value_fn::call_traits<R, void(Vs...)>::overload !=
- asio_execution_set_value_fn::ill_formed>
- {
- };
- #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- template <typename R, typename... Vs>
- constexpr bool can_set_value_v = can_set_value<R, Vs...>::value;
- #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- template <typename R, typename... Vs>
- struct is_nothrow_set_value :
- integral_constant<bool,
- asio_execution_set_value_fn::call_traits<R, void(Vs...)>::is_noexcept>
- {
- };
- #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- template <typename R, typename... Vs>
- constexpr bool is_nothrow_set_value_v
- = is_nothrow_set_value<R, Vs...>::value;
- #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- template <typename R, typename = void,
- typename = void, typename = void, typename = void, typename = void,
- typename = void, typename = void, typename = void, typename = void>
- struct can_set_value;
- template <typename R, typename = void,
- typename = void, typename = void, typename = void, typename = void,
- typename = void, typename = void, typename = void, typename = void>
- struct is_nothrow_set_value;
- template <typename R>
- struct can_set_value<R> :
- integral_constant<bool,
- asio_execution_set_value_fn::call_traits<R, void()>::overload !=
- asio_execution_set_value_fn::ill_formed>
- {
- };
- template <typename R>
- struct is_nothrow_set_value<R> :
- integral_constant<bool,
- asio_execution_set_value_fn::call_traits<R, void()>::is_noexcept>
- {
- };
- #define BOOST_ASIO_PRIVATE_SET_VALUE_TRAITS_DEF(n) \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- struct can_set_value<R, BOOST_ASIO_VARIADIC_TARGS(n)> : \
- integral_constant<bool, \
- asio_execution_set_value_fn::call_traits<R, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::overload != \
- asio_execution_set_value_fn::ill_formed> \
- { \
- }; \
- \
- template <typename R, BOOST_ASIO_VARIADIC_TPARAMS(n)> \
- struct is_nothrow_set_value<R, BOOST_ASIO_VARIADIC_TARGS(n)> : \
- integral_constant<bool, \
- asio_execution_set_value_fn::call_traits<R, \
- void(BOOST_ASIO_VARIADIC_TARGS(n))>::is_noexcept> \
- { \
- }; \
- /**/
- BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_SET_VALUE_TRAITS_DEF)
- #undef BOOST_ASIO_PRIVATE_SET_VALUE_TRAITS_DEF
- #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES)
- } // namespace execution
- } // namespace asio
- } // namespace boost
- #endif // defined(GENERATING_DOCUMENTATION)
- #include <boost/asio/detail/pop_options.hpp>
- #endif // BOOST_ASIO_EXECUTION_SET_VALUE_HPP
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