1 //
2 // detail/reactive_socket_recvfrom_op.hpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2019 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_RECVFROM_OP_HPP
12 #define BOOST_ASIO_DETAIL_REACTIVE_SOCKET_RECVFROM_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/memory.hpp>
23 #include <boost/asio/detail/reactor_op.hpp>
24 #include <boost/asio/detail/socket_ops.hpp>
25 
26 #include <boost/asio/detail/push_options.hpp>
27 
28 namespace boost {
29 namespace asio {
30 namespace detail {
31 
32 template <typename MutableBufferSequence, typename Endpoint>
33 class reactive_socket_recvfrom_op_base : public reactor_op
34 {
35 public:
reactive_socket_recvfrom_op_base(socket_type socket,int protocol_type,const MutableBufferSequence & buffers,Endpoint & endpoint,socket_base::message_flags flags,func_type complete_func)36   reactive_socket_recvfrom_op_base(socket_type socket, int protocol_type,
37       const MutableBufferSequence& buffers, Endpoint& endpoint,
38       socket_base::message_flags flags, func_type complete_func)
39     : reactor_op(&reactive_socket_recvfrom_op_base::do_perform, complete_func),
40       socket_(socket),
41       protocol_type_(protocol_type),
42       buffers_(buffers),
43       sender_endpoint_(endpoint),
44       flags_(flags)
45   {
46   }
47 
do_perform(reactor_op * base)48   static status do_perform(reactor_op* base)
49   {
50     reactive_socket_recvfrom_op_base* o(
51         static_cast<reactive_socket_recvfrom_op_base*>(base));
52 
53     buffer_sequence_adapter<boost::asio::mutable_buffer,
54         MutableBufferSequence> bufs(o->buffers_);
55 
56     std::size_t addr_len = o->sender_endpoint_.capacity();
57     status result = socket_ops::non_blocking_recvfrom(o->socket_,
58         bufs.buffers(), bufs.count(), o->flags_,
59         o->sender_endpoint_.data(), &addr_len,
60         o->ec_, o->bytes_transferred_) ? done : not_done;
61 
62     if (result && !o->ec_)
63       o->sender_endpoint_.resize(addr_len);
64 
65     BOOST_ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_recvfrom",
66           o->ec_, o->bytes_transferred_));
67 
68     return result;
69   }
70 
71 private:
72   socket_type socket_;
73   int protocol_type_;
74   MutableBufferSequence buffers_;
75   Endpoint& sender_endpoint_;
76   socket_base::message_flags flags_;
77 };
78 
79 template <typename MutableBufferSequence, typename Endpoint,
80     typename Handler, typename IoExecutor>
81 class reactive_socket_recvfrom_op :
82   public reactive_socket_recvfrom_op_base<MutableBufferSequence, Endpoint>
83 {
84 public:
85   BOOST_ASIO_DEFINE_HANDLER_PTR(reactive_socket_recvfrom_op);
86 
reactive_socket_recvfrom_op(socket_type socket,int protocol_type,const MutableBufferSequence & buffers,Endpoint & endpoint,socket_base::message_flags flags,Handler & handler,const IoExecutor & io_ex)87   reactive_socket_recvfrom_op(socket_type socket, int protocol_type,
88       const MutableBufferSequence& buffers, Endpoint& endpoint,
89       socket_base::message_flags flags, Handler& handler,
90       const IoExecutor& io_ex)
91     : reactive_socket_recvfrom_op_base<MutableBufferSequence, Endpoint>(
92         socket, protocol_type, buffers, endpoint, flags,
93         &reactive_socket_recvfrom_op::do_complete),
94       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
95       io_executor_(io_ex)
96   {
97     handler_work<Handler, IoExecutor>::start(handler_, io_executor_);
98   }
99 
do_complete(void * owner,operation * base,const boost::system::error_code &,std::size_t)100   static void do_complete(void* owner, operation* base,
101       const boost::system::error_code& /*ec*/,
102       std::size_t /*bytes_transferred*/)
103   {
104     // Take ownership of the handler object.
105     reactive_socket_recvfrom_op* o(
106         static_cast<reactive_socket_recvfrom_op*>(base));
107     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
108     handler_work<Handler, IoExecutor> w(o->handler_, o->io_executor_);
109 
110     BOOST_ASIO_HANDLER_COMPLETION((*o));
111 
112     // Make a copy of the handler so that the memory can be deallocated before
113     // the upcall is made. Even if we're not about to make an upcall, a
114     // sub-object of the handler may be the true owner of the memory associated
115     // with the handler. Consequently, a local copy of the handler is required
116     // to ensure that any owning sub-object remains valid until after we have
117     // deallocated the memory here.
118     detail::binder2<Handler, boost::system::error_code, std::size_t>
119       handler(o->handler_, o->ec_, o->bytes_transferred_);
120     p.h = boost::asio::detail::addressof(handler.handler_);
121     p.reset();
122 
123     // Make the upcall if required.
124     if (owner)
125     {
126       fenced_block b(fenced_block::half);
127       BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
128       w.complete(handler, handler.handler_);
129       BOOST_ASIO_HANDLER_INVOCATION_END;
130     }
131   }
132 
133 private:
134   Handler handler_;
135   IoExecutor io_executor_;
136 };
137 
138 } // namespace detail
139 } // namespace asio
140 } // namespace boost
141 
142 #include <boost/asio/detail/pop_options.hpp>
143 
144 #endif // BOOST_ASIO_DETAIL_REACTIVE_SOCKET_RECVFROM_OP_HPP
145