experimental/detail/channel_receive_op.hpp

0001 //
0002 // experimental/detail/channel_receive_op.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_EXPERIMENTAL_DETAIL_CHANNEL_RECEIVE_OP_HPP
0012 #define BOOST_ASIO_EXPERIMENTAL_DETAIL_CHANNEL_RECEIVE_OP_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/completion_handler.hpp>
0021 #include <boost/asio/detail/handler_alloc_helpers.hpp>
0022 #include <boost/asio/error.hpp>
0023 #include <boost/asio/experimental/detail/channel_operation.hpp>
0024
0025 #include <boost/asio/detail/push_options.hpp>
0026
0027 namespace boost {
0028 namespace asio {
0029 namespace experimental {
0030 namespace detail {
0031
0032 template <typename Payload>
0033 class channel_receive : public channel_operation
0034 {
0035 public:
0036   void immediate(Payload payload)
0037   {
0038     func_(this, immediate_op, &payload);
0039   }
0040
0041   void post(Payload payload)
0042   {
0043     func_(this, post_op, &payload);
0044   }
0045
0046   void dispatch(Payload payload)
0047   {
0048     func_(this, dispatch_op, &payload);
0049   }
0050
0051 protected:
0052   channel_receive(func_type func)
0053     : channel_operation(func)
0054   {
0055   }
0056 };
0057
0058 template <typename Payload, typename Handler, typename IoExecutor>
0059 class channel_receive_op : public channel_receive<Payload>
0060 {
0061 public:
0062   BOOST_ASIO_DEFINE_HANDLER_PTR(channel_receive_op);
0063
0064   template <typename... Args>
0065   channel_receive_op(Handler& handler, const IoExecutor& io_ex)
0066     : channel_receive<Payload>(&channel_receive_op::do_action),
0067       handler_(static_cast<Handler&&>(handler)),
0068       work_(handler_, io_ex)
0069   {
0070   }
0071
0072   static void do_action(channel_operation* base,
0073       channel_operation::action a, void* v)
0074   {
0075     // Take ownership of the operation object.
0076     channel_receive_op* o(static_cast<channel_receive_op*>(base));
0077     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
0078
0079     BOOST_ASIO_HANDLER_COMPLETION((*o));
0080
0081     // Take ownership of the operation's outstanding work.
0082     channel_operation::handler_work<Handler, IoExecutor> w(
0083         static_cast<channel_operation::handler_work<Handler, IoExecutor>&&>(
0084           o->work_));
0085
0086     // Make a copy of the handler so that the memory can be deallocated before
0087     // the handler is posted. Even if we're not about to post the handler, a
0088     // sub-object of the handler may be the true owner of the memory associated
0089     // with the handler. Consequently, a local copy of the handler is required
0090     // to ensure that any owning sub-object remains valid until after we have
0091     // deallocated the memory here.
0092     if (a != channel_operation::destroy_op)
0093     {
0094       Payload* payload = static_cast<Payload*>(v);
0095       boost::asio::detail::completion_payload_handler<Payload, Handler> handler(
0096           static_cast<Payload&&>(*payload), o->handler_);
0097       p.h = boost::asio::detail::addressof(handler.handler_);
0098       p.reset();
0099       BOOST_ASIO_HANDLER_INVOCATION_BEGIN(());
0100       if (a == channel_operation::immediate_op)
0101         w.immediate(handler, handler.handler_, 0);
0102       else if (a == channel_operation::dispatch_op)
0103         w.dispatch(handler, handler.handler_);
0104       else
0105         w.post(handler, handler.handler_);
0106       BOOST_ASIO_HANDLER_INVOCATION_END;
0107     }
0108     else
0109     {
0110       boost::asio::detail::binder0<Handler> handler(o->handler_);
0111       p.h = boost::asio::detail::addressof(handler.handler_);
0112       p.reset();
0113     }
0114   }
0115
0116 private:
0117   Handler handler_;
0118   channel_operation::handler_work<Handler, IoExecutor> work_;
0119 };
0120
0121 } // namespace detail
0122 } // namespace experimental
0123 } // namespace asio
0124 } // namespace boost
0125
0126 #include <boost/asio/detail/pop_options.hpp>
0127
0128 #endif // BOOST_ASIO_EXPERIMENTAL_DETAIL_CHANNEL_RECEIVE_OP_HPP