asio/detail/work_dispatcher.hpp

0001 //
0002 // detail/work_dispatcher.hpp
0003 // ~~~~~~~~~~~~~~~~~~~~~~~~~~
0004 //
0005 // Copyright (c) 2003-2023 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_DETAIL_WORK_DISPATCHER_HPP
0012 #define BOOST_ASIO_DETAIL_WORK_DISPATCHER_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/detail/bind_handler.hpp>
0020 #include <boost/asio/detail/type_traits.hpp>
0021 #include <boost/asio/associated_executor.hpp>
0022 #include <boost/asio/associated_allocator.hpp>
0023 #include <boost/asio/executor_work_guard.hpp>
0024 #include <boost/asio/execution/executor.hpp>
0025 #include <boost/asio/execution/allocator.hpp>
0026 #include <boost/asio/execution/blocking.hpp>
0027 #include <boost/asio/execution/outstanding_work.hpp>
0028 #include <boost/asio/prefer.hpp>
0029
0030 #include <boost/asio/detail/push_options.hpp>
0031
0032 namespace boost {
0033 namespace asio {
0034 namespace detail {
0035
0036 template <typename Handler, typename Executor, typename = void>
0037 struct is_work_dispatcher_required : true_type
0038 {
0039 };
0040
0041 template <typename Handler, typename Executor>
0042 struct is_work_dispatcher_required<Handler, Executor,
0043     enable_if_t<
0044       is_same<
0045         typename associated_executor<Handler,
0046           Executor>::asio_associated_executor_is_unspecialised,
0047         void
0048       >::value
0049     >> : false_type
0050 {
0051 };
0052
0053 template <typename Handler, typename Executor, typename = void>
0054 class work_dispatcher
0055 {
0056 public:
0057   template <typename CompletionHandler>
0058   work_dispatcher(CompletionHandler&& handler,
0059       const Executor& handler_ex)
0060     : handler_(static_cast<CompletionHandler&&>(handler)),
0061       executor_(boost::asio::prefer(handler_ex,
0062           execution::outstanding_work.tracked))
0063   {
0064   }
0065
0066   work_dispatcher(const work_dispatcher& other)
0067     : handler_(other.handler_),
0068       executor_(other.executor_)
0069   {
0070   }
0071
0072   work_dispatcher(work_dispatcher&& other)
0073     : handler_(static_cast<Handler&&>(other.handler_)),
0074       executor_(static_cast<work_executor_type&&>(other.executor_))
0075   {
0076   }
0077
0078   void operator()()
0079   {
0080     associated_allocator_t<Handler> alloc((get_associated_allocator)(handler_));
0081     boost::asio::prefer(executor_, execution::allocator(alloc)).execute(
0082         boost::asio::detail::bind_handler(
0083           static_cast<Handler&&>(handler_)));
0084   }
0085
0086 private:
0087   typedef decay_t<
0088       prefer_result_t<const Executor&,
0089         execution::outstanding_work_t::tracked_t
0090       >
0091     > work_executor_type;
0092
0093   Handler handler_;
0094   work_executor_type executor_;
0095 };
0096
0097 #if !defined(BOOST_ASIO_NO_TS_EXECUTORS)
0098
0099 template <typename Handler, typename Executor>
0100 class work_dispatcher<Handler, Executor,
0101     enable_if_t<!execution::is_executor<Executor>::value>>
0102 {
0103 public:
0104   template <typename CompletionHandler>
0105   work_dispatcher(CompletionHandler&& handler, const Executor& handler_ex)
0106     : work_(handler_ex),
0107       handler_(static_cast<CompletionHandler&&>(handler))
0108   {
0109   }
0110
0111   work_dispatcher(const work_dispatcher& other)
0112     : work_(other.work_),
0113       handler_(other.handler_)
0114   {
0115   }
0116
0117   work_dispatcher(work_dispatcher&& other)
0118     : work_(static_cast<executor_work_guard<Executor>&&>(other.work_)),
0119       handler_(static_cast<Handler&&>(other.handler_))
0120   {
0121   }
0122
0123   void operator()()
0124   {
0125     associated_allocator_t<Handler> alloc((get_associated_allocator)(handler_));
0126     work_.get_executor().dispatch(
0127         boost::asio::detail::bind_handler(
0128           static_cast<Handler&&>(handler_)), alloc);
0129     work_.reset();
0130   }
0131
0132 private:
0133   executor_work_guard<Executor> work_;
0134   Handler handler_;
0135 };
0136
0137 #endif // !defined(BOOST_ASIO_NO_TS_EXECUTORS)
0138
0139 } // namespace detail
0140 } // namespace asio
0141 } // namespace boost
0142
0143 #include <boost/asio/detail/pop_options.hpp>
0144
0145 #endif // BOOST_ASIO_DETAIL_WORK_DISPATCHER_HPP