asio/impl/consign.hpp

0001 //
0002 // impl/consign.hpp
0003 // ~~~~~~~~~~~~~~~~
0004 //
0005 // Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff dot com)
0006 //
0007 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0008 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0009 //
0010
0011 #ifndef BOOST_ASIO_IMPL_CONSIGN_HPP
0012 #define BOOST_ASIO_IMPL_CONSIGN_HPP
0013
0014 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
0015 # pragma once
0016 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
0017
0018 #include <boost/asio/detail/config.hpp>
0019 #include <boost/asio/associator.hpp>
0020 #include <boost/asio/async_result.hpp>
0021 #include <boost/asio/detail/handler_cont_helpers.hpp>
0022 #include <boost/asio/detail/initiation_base.hpp>
0023 #include <boost/asio/detail/type_traits.hpp>
0024 #include <boost/asio/detail/utility.hpp>
0025
0026 #include <boost/asio/detail/push_options.hpp>
0027
0028 namespace boost {
0029 namespace asio {
0030 namespace detail {
0031
0032 // Class to adapt a consign_t as a completion handler.
0033 template <typename Handler, typename... Values>
0034 class consign_handler
0035 {
0036 public:
0037   typedef void result_type;
0038
0039   template <typename H>
0040   consign_handler(H&& handler, std::tuple<Values...> values)
0041     : handler_(static_cast<H&&>(handler)),
0042       values_(static_cast<std::tuple<Values...>&&>(values))
0043   {
0044   }
0045
0046   template <typename... Args>
0047   void operator()(Args&&... args)
0048   {
0049     static_cast<Handler&&>(handler_)(static_cast<Args&&>(args)...);
0050   }
0051
0052 //private:
0053   Handler handler_;
0054   std::tuple<Values...> values_;
0055 };
0056
0057 template <typename Handler>
0058 inline bool asio_handler_is_continuation(
0059     consign_handler<Handler>* this_handler)
0060 {
0061   return boost_asio_handler_cont_helpers::is_continuation(
0062       this_handler->handler_);
0063 }
0064
0065 } // namespace detail
0066
0067 #if !defined(GENERATING_DOCUMENTATION)
0068
0069 template <typename CompletionToken, typename... Values, typename... Signatures>
0070 struct async_result<consign_t<CompletionToken, Values...>, Signatures...>
0071   : async_result<CompletionToken, Signatures...>
0072 {
0073   template <typename Initiation>
0074   struct init_wrapper : detail::initiation_base<Initiation>
0075   {
0076     using detail::initiation_base<Initiation>::initiation_base;
0077
0078     template <typename Handler, typename... Args>
0079     void operator()(Handler&& handler,
0080         std::tuple<Values...> values, Args&&... args) &&
0081     {
0082       static_cast<Initiation&&>(*this)(
0083           detail::consign_handler<decay_t<Handler>, Values...>(
0084             static_cast<Handler&&>(handler),
0085             static_cast<std::tuple<Values...>&&>(values)),
0086           static_cast<Args&&>(args)...);
0087     }
0088
0089     template <typename Handler, typename... Args>
0090     void operator()(Handler&& handler,
0091         std::tuple<Values...> values, Args&&... args) const &
0092     {
0093       static_cast<const Initiation&>(*this)(
0094           detail::consign_handler<decay_t<Handler>, Values...>(
0095             static_cast<Handler&&>(handler),
0096             static_cast<std::tuple<Values...>&&>(values)),
0097           static_cast<Args&&>(args)...);
0098     }
0099   };
0100
0101   template <typename Initiation, typename RawCompletionToken, typename... Args>
0102   static auto initiate(Initiation&& initiation,
0103       RawCompletionToken&& token, Args&&... args)
0104     -> decltype(
0105       async_initiate<CompletionToken, Signatures...>(
0106         init_wrapper<decay_t<Initiation>>(
0107           static_cast<Initiation&&>(initiation)),
0108         token.token_, static_cast<std::tuple<Values...>&&>(token.values_),
0109         static_cast<Args&&>(args)...))
0110   {
0111     return async_initiate<CompletionToken, Signatures...>(
0112         init_wrapper<decay_t<Initiation>>(
0113           static_cast<Initiation&&>(initiation)),
0114         token.token_, static_cast<std::tuple<Values...>&&>(token.values_),
0115         static_cast<Args&&>(args)...);
0116   }
0117 };
0118
0119 template <template <typename, typename> class Associator,
0120     typename Handler, typename... Values, typename DefaultCandidate>
0121 struct associator<Associator,
0122     detail::consign_handler<Handler, Values...>, DefaultCandidate>
0123   : Associator<Handler, DefaultCandidate>
0124 {
0125   static typename Associator<Handler, DefaultCandidate>::type get(
0126       const detail::consign_handler<Handler, Values...>& h) noexcept
0127   {
0128     return Associator<Handler, DefaultCandidate>::get(h.handler_);
0129   }
0130
0131   static auto get(const detail::consign_handler<Handler, Values...>& h,
0132       const DefaultCandidate& c) noexcept
0133     -> decltype(Associator<Handler, DefaultCandidate>::get(h.handler_, c))
0134   {
0135     return Associator<Handler, DefaultCandidate>::get(h.handler_, c);
0136   }
0137 };
0138
0139 #endif // !defined(GENERATING_DOCUMENTATION)
0140
0141 } // namespace asio
0142 } // namespace boost
0143
0144 #include <boost/asio/detail/pop_options.hpp>
0145
0146 #endif // BOOST_ASIO_IMPL_CONSIGN_HPP