1 //
2 // detail/reactive_socket_recv_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_SOCKET_RECV_OP_HPP
12 #define BOOST_ASIO_DETAIL_REACTIVE_SOCKET_RECV_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/buffer_sequence_adapter.hpp>
21 #include <boost/asio/detail/fenced_block.hpp>
22 #include <boost/asio/detail/handler_alloc_helpers.hpp>
23 #include <boost/asio/detail/handler_invoke_helpers.hpp>
24 #include <boost/asio/detail/handler_work.hpp>
25 #include <boost/asio/detail/memory.hpp>
26 #include <boost/asio/detail/reactor_op.hpp>
27 #include <boost/asio/detail/socket_ops.hpp>
28 
29 #include <boost/asio/detail/push_options.hpp>
30 
31 namespace boost {
32 namespace asio {
33 namespace detail {
34 
35 template <typename MutableBufferSequence>
36 class reactive_socket_recv_op_base : public reactor_op
37 {
38 public:
reactive_socket_recv_op_base(const boost::system::error_code & success_ec,socket_type socket,socket_ops::state_type state,const MutableBufferSequence & buffers,socket_base::message_flags flags,func_type complete_func)39   reactive_socket_recv_op_base(const boost::system::error_code& success_ec,
40       socket_type socket, socket_ops::state_type state,
41       const MutableBufferSequence& buffers,
42       socket_base::message_flags flags, func_type complete_func)
43     : reactor_op(success_ec,
44         &reactive_socket_recv_op_base::do_perform, complete_func),
45       socket_(socket),
46       state_(state),
47       buffers_(buffers),
48       flags_(flags)
49   {
50   }
51 
do_perform(reactor_op * base)52   static status do_perform(reactor_op* base)
53   {
54     reactive_socket_recv_op_base* o(
55         static_cast<reactive_socket_recv_op_base*>(base));
56 
57     typedef buffer_sequence_adapter<boost::asio::mutable_buffer,
58         MutableBufferSequence> bufs_type;
59 
60     status result;
61     if (bufs_type::is_single_buffer)
62     {
63       result = socket_ops::non_blocking_recv1(o->socket_,
64           bufs_type::first(o->buffers_).data(),
65           bufs_type::first(o->buffers_).size(), o->flags_,
66           (o->state_ & socket_ops::stream_oriented) != 0,
67           o->ec_, o->bytes_transferred_) ? done : not_done;
68     }
69     else
70     {
71       bufs_type bufs(o->buffers_);
72       result = socket_ops::non_blocking_recv(o->socket_,
73           bufs.buffers(), bufs.count(), o->flags_,
74           (o->state_ & socket_ops::stream_oriented) != 0,
75           o->ec_, o->bytes_transferred_) ? done : not_done;
76     }
77 
78     if (result == done)
79       if ((o->state_ & socket_ops::stream_oriented) != 0)
80         if (o->bytes_transferred_ == 0)
81           result = done_and_exhausted;
82 
83     BOOST_ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_recv",
84           o->ec_, o->bytes_transferred_));
85 
86     return result;
87   }
88 
89 private:
90   socket_type socket_;
91   socket_ops::state_type state_;
92   MutableBufferSequence buffers_;
93   socket_base::message_flags flags_;
94 };
95 
96 template <typename MutableBufferSequence, typename Handler, typename IoExecutor>
97 class reactive_socket_recv_op :
98   public reactive_socket_recv_op_base<MutableBufferSequence>
99 {
100 public:
101   BOOST_ASIO_DEFINE_HANDLER_PTR(reactive_socket_recv_op);
102 
reactive_socket_recv_op(const boost::system::error_code & success_ec,socket_type socket,socket_ops::state_type state,const MutableBufferSequence & buffers,socket_base::message_flags flags,Handler & handler,const IoExecutor & io_ex)103   reactive_socket_recv_op(const boost::system::error_code& success_ec,
104       socket_type socket, socket_ops::state_type state,
105       const MutableBufferSequence& buffers, socket_base::message_flags flags,
106       Handler& handler, const IoExecutor& io_ex)
107     : reactive_socket_recv_op_base<MutableBufferSequence>(success_ec, socket,
108         state, buffers, flags, &reactive_socket_recv_op::do_complete),
109       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
110       work_(handler_, io_ex)
111   {
112   }
113 
do_complete(void * owner,operation * base,const boost::system::error_code &,std::size_t)114   static void do_complete(void* owner, operation* base,
115       const boost::system::error_code& /*ec*/,
116       std::size_t /*bytes_transferred*/)
117   {
118     // Take ownership of the handler object.
119     reactive_socket_recv_op* o(static_cast<reactive_socket_recv_op*>(base));
120     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
121 
122     BOOST_ASIO_HANDLER_COMPLETION((*o));
123 
124     // Take ownership of the operation's outstanding work.
125     handler_work<Handler, IoExecutor> w(
126         BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)(
127           o->work_));
128 
129     // Make a copy of the handler so that the memory can be deallocated before
130     // the upcall is made. Even if we're not about to make an upcall, a
131     // sub-object of the handler may be the true owner of the memory associated
132     // with the handler. Consequently, a local copy of the handler is required
133     // to ensure that any owning sub-object remains valid until after we have
134     // deallocated the memory here.
135     detail::binder2<Handler, boost::system::error_code, std::size_t>
136       handler(o->handler_, o->ec_, o->bytes_transferred_);
137     p.h = boost::asio::detail::addressof(handler.handler_);
138     p.reset();
139 
140     // Make the upcall if required.
141     if (owner)
142     {
143       fenced_block b(fenced_block::half);
144       BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
145       w.complete(handler, handler.handler_);
146       BOOST_ASIO_HANDLER_INVOCATION_END;
147     }
148   }
149 
150 private:
151   Handler handler_;
152   handler_work<Handler, IoExecutor> work_;
153 };
154 
155 } // namespace detail
156 } // namespace asio
157 } // namespace boost
158 
159 #include <boost/asio/detail/pop_options.hpp>
160 
161 #endif // BOOST_ASIO_DETAIL_REACTIVE_SOCKET_RECV_OP_HPP
162