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- //
- // execution/set_error.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_ERROR_HPP
- #define BOOST_ASIO_EXECUTION_SET_ERROR_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/traits/set_error_member.hpp>
- #include <boost/asio/traits/set_error_free.hpp>
- #include <boost/asio/detail/push_options.hpp>
- #if defined(GENERATING_DOCUMENTATION)
- namespace boost {
- namespace asio {
- namespace execution {
- /// A customisation point that delivers an error notification to a receiver.
- /**
- * The name <tt>execution::set_error</tt> denotes a customisation point object.
- * The expression <tt>execution::set_error(R, E)</tt> for some subexpressions
- * <tt>R</tt> and <tt>E</tt> are expression-equivalent to:
- *
- * @li <tt>R.set_error(E)</tt>, if that expression is valid. If the function
- * selected does not send the error <tt>E</tt> to the receiver <tt>R</tt>'s
- * error channel, the program is ill-formed with no diagnostic required.
- *
- * @li Otherwise, <tt>set_error(R, E)</tt>, if that expression is valid, with
- * overload resolution performed in a context that includes the declaration
- * <tt>void set_error();</tt> and that does not include a declaration of
- * <tt>execution::set_error</tt>. If the function selected by overload
- * resolution does not send the error <tt>E</tt> to the receiver <tt>R</tt>'s
- * error channel, the program is ill-formed with no diagnostic required.
- *
- * @li Otherwise, <tt>execution::set_error(R, E)</tt> is ill-formed.
- */
- inline constexpr unspecified set_error = unspecified;
- /// A type trait that determines whether a @c set_error expression is
- /// well-formed.
- /**
- * Class template @c can_set_error is a trait that is derived from
- * @c true_type if the expression <tt>execution::set_error(std::declval<R>(),
- * std::declval<E>())</tt> is well formed; otherwise @c false_type.
- */
- template <typename R, typename E>
- struct can_set_error :
- integral_constant<bool, automatically_determined>
- {
- };
- } // namespace execution
- } // namespace asio
- } // namespace boost
- #else // defined(GENERATING_DOCUMENTATION)
- namespace asio_execution_set_error_fn {
- using boost::asio::decay;
- using boost::asio::declval;
- using boost::asio::enable_if;
- using boost::asio::traits::set_error_free;
- using boost::asio::traits::set_error_member;
- void set_error();
- enum overload_type
- {
- call_member,
- call_free,
- ill_formed
- };
- template <typename R, typename E, 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 E>
- struct call_traits<R, void(E),
- typename enable_if<
- set_error_member<R, E>::is_valid
- >::type> :
- set_error_member<R, E>
- {
- BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_member);
- };
- template <typename R, typename E>
- struct call_traits<R, void(E),
- typename enable_if<
- !set_error_member<R, E>::is_valid
- >::type,
- typename enable_if<
- set_error_free<R, E>::is_valid
- >::type> :
- set_error_free<R, E>
- {
- BOOST_ASIO_STATIC_CONSTEXPR(overload_type, overload = call_free);
- };
- struct impl
- {
- #if defined(BOOST_ASIO_HAS_MOVE)
- template <typename R, typename E>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R, void(E)>::overload == call_member,
- typename call_traits<R, void(E)>::result_type
- >::type
- operator()(R&& r, E&& e) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R, void(E)>::is_noexcept))
- {
- return BOOST_ASIO_MOVE_CAST(R)(r).set_error(BOOST_ASIO_MOVE_CAST(E)(e));
- }
- template <typename R, typename E>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R, void(E)>::overload == call_free,
- typename call_traits<R, void(E)>::result_type
- >::type
- operator()(R&& r, E&& e) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R, void(E)>::is_noexcept))
- {
- return set_error(BOOST_ASIO_MOVE_CAST(R)(r), BOOST_ASIO_MOVE_CAST(E)(e));
- }
- #else // defined(BOOST_ASIO_HAS_MOVE)
- template <typename R, typename E>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R&, void(const E&)>::overload == call_member,
- typename call_traits<R&, void(const E&)>::result_type
- >::type
- operator()(R& r, const E& e) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R&, void(const E&)>::is_noexcept))
- {
- return r.set_error(e);
- }
- template <typename R, typename E>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<const R&, void(const E&)>::overload == call_member,
- typename call_traits<const R&, void(const E&)>::result_type
- >::type
- operator()(const R& r, const E& e) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<const R&, void(const E&)>::is_noexcept))
- {
- return r.set_error(e);
- }
- template <typename R, typename E>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<R&, void(const E&)>::overload == call_free,
- typename call_traits<R&, void(const E&)>::result_type
- >::type
- operator()(R& r, const E& e) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<R&, void(const E&)>::is_noexcept))
- {
- return set_error(r, e);
- }
- template <typename R, typename E>
- BOOST_ASIO_CONSTEXPR typename enable_if<
- call_traits<const R&, void(const E&)>::overload == call_free,
- typename call_traits<const R&, void(const E&)>::result_type
- >::type
- operator()(const R& r, const E& e) const
- BOOST_ASIO_NOEXCEPT_IF((
- call_traits<const R&, void(const E&)>::is_noexcept))
- {
- return set_error(r, e);
- }
- #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_error_fn
- namespace boost {
- namespace asio {
- namespace execution {
- namespace {
- static BOOST_ASIO_CONSTEXPR const asio_execution_set_error_fn::impl&
- set_error = asio_execution_set_error_fn::static_instance<>::instance;
- } // namespace
- template <typename R, typename E>
- struct can_set_error :
- integral_constant<bool,
- asio_execution_set_error_fn::call_traits<R, void(E)>::overload !=
- asio_execution_set_error_fn::ill_formed>
- {
- };
- #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- template <typename R, typename E>
- constexpr bool can_set_error_v = can_set_error<R, E>::value;
- #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- template <typename R, typename E>
- struct is_nothrow_set_error :
- integral_constant<bool,
- asio_execution_set_error_fn::call_traits<R, void(E)>::is_noexcept>
- {
- };
- #if defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- template <typename R, typename E>
- constexpr bool is_nothrow_set_error_v
- = is_nothrow_set_error<R, E>::value;
- #endif // defined(BOOST_ASIO_HAS_VARIABLE_TEMPLATES)
- } // namespace execution
- } // namespace asio
- } // namespace boost
- #endif // defined(GENERATING_DOCUMENTATION)
- #include <boost/asio/detail/pop_options.hpp>
- #endif // BOOST_ASIO_EXECUTION_SET_ERROR_HPP
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