1 //
2 // detail/reactive_wait_op.hpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6 //
7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 //
10 
11 #ifndef BOOST_ASIO_DETAIL_REACTIVE_WAIT_OP_HPP
12 #define BOOST_ASIO_DETAIL_REACTIVE_WAIT_OP_HPP
13 
14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
15 # pragma once
16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17 
18 #include <boost/asio/detail/config.hpp>
19 #include <boost/asio/detail/bind_handler.hpp>
20 #include <boost/asio/detail/fenced_block.hpp>
21 #include <boost/asio/detail/handler_alloc_helpers.hpp>
22 #include <boost/asio/detail/handler_invoke_helpers.hpp>
23 #include <boost/asio/detail/handler_work.hpp>
24 #include <boost/asio/detail/memory.hpp>
25 #include <boost/asio/detail/reactor_op.hpp>
26 
27 #include <boost/asio/detail/push_options.hpp>
28 
29 namespace boost {
30 namespace asio {
31 namespace detail {
32 
33 template <typename Handler, typename IoExecutor>
34 class reactive_wait_op : public reactor_op
35 {
36 public:
37   BOOST_ASIO_DEFINE_HANDLER_PTR(reactive_wait_op);
38 
reactive_wait_op(const boost::system::error_code & success_ec,Handler & handler,const IoExecutor & io_ex)39   reactive_wait_op(const boost::system::error_code& success_ec,
40       Handler& handler, const IoExecutor& io_ex)
41     : reactor_op(success_ec, &reactive_wait_op::do_perform,
42         &reactive_wait_op::do_complete),
43       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
44       work_(handler_, io_ex)
45   {
46   }
47 
do_perform(reactor_op *)48   static status do_perform(reactor_op*)
49   {
50     return done;
51   }
52 
do_complete(void * owner,operation * base,const boost::system::error_code &,std::size_t)53   static void do_complete(void* owner, operation* base,
54       const boost::system::error_code& /*ec*/,
55       std::size_t /*bytes_transferred*/)
56   {
57     // Take ownership of the handler object.
58     reactive_wait_op* o(static_cast<reactive_wait_op*>(base));
59     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
60 
61     BOOST_ASIO_HANDLER_COMPLETION((*o));
62 
63     // Take ownership of the operation's outstanding work.
64     handler_work<Handler, IoExecutor> w(
65         BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)(
66           o->work_));
67 
68     // Make a copy of the handler so that the memory can be deallocated before
69     // the upcall is made. Even if we're not about to make an upcall, a
70     // sub-object of the handler may be the true owner of the memory associated
71     // with the handler. Consequently, a local copy of the handler is required
72     // to ensure that any owning sub-object remains valid until after we have
73     // deallocated the memory here.
74     detail::binder1<Handler, boost::system::error_code>
75       handler(o->handler_, o->ec_);
76     p.h = boost::asio::detail::addressof(handler.handler_);
77     p.reset();
78 
79     // Make the upcall if required.
80     if (owner)
81     {
82       fenced_block b(fenced_block::half);
83       BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_));
84       w.complete(handler, handler.handler_);
85       BOOST_ASIO_HANDLER_INVOCATION_END;
86     }
87   }
88 
89 private:
90   Handler handler_;
91   handler_work<Handler, IoExecutor> work_;
92 };
93 
94 } // namespace detail
95 } // namespace asio
96 } // namespace boost
97 
98 #include <boost/asio/detail/pop_options.hpp>
99 
100 #endif // BOOST_ASIO_DETAIL_REACTIVE_WAIT_OP_HPP
101