1 //
2 // detail/descriptor_read_op.hpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2016 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 ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
12 #define ASIO_DETAIL_DESCRIPTOR_READ_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 "asio/detail/config.hpp"
19 
20 #if !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
21 
22 #include "asio/detail/bind_handler.hpp"
23 #include "asio/detail/buffer_sequence_adapter.hpp"
24 #include "asio/detail/descriptor_ops.hpp"
25 #include "asio/detail/fenced_block.hpp"
26 #include "asio/detail/handler_work.hpp"
27 #include "asio/detail/memory.hpp"
28 #include "asio/detail/reactor_op.hpp"
29 
30 #include "asio/detail/push_options.hpp"
31 
32 namespace asio {
33 namespace detail {
34 
35 template <typename MutableBufferSequence>
36 class descriptor_read_op_base : public reactor_op
37 {
38 public:
descriptor_read_op_base(int descriptor,const MutableBufferSequence & buffers,func_type complete_func)39   descriptor_read_op_base(int descriptor,
40       const MutableBufferSequence& buffers, func_type complete_func)
41     : reactor_op(&descriptor_read_op_base::do_perform, complete_func),
42       descriptor_(descriptor),
43       buffers_(buffers)
44   {
45   }
46 
do_perform(reactor_op * base)47   static status do_perform(reactor_op* base)
48   {
49     descriptor_read_op_base* o(static_cast<descriptor_read_op_base*>(base));
50 
51     buffer_sequence_adapter<asio::mutable_buffer,
52         MutableBufferSequence> bufs(o->buffers_);
53 
54     status result = descriptor_ops::non_blocking_read(o->descriptor_,
55         bufs.buffers(), bufs.count(), o->ec_, o->bytes_transferred_)
56       ? done : not_done;
57 
58     ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_read",
59           o->ec_, o->bytes_transferred_));
60 
61     return result;
62   }
63 
64 private:
65   int descriptor_;
66   MutableBufferSequence buffers_;
67 };
68 
69 template <typename MutableBufferSequence, typename Handler>
70 class descriptor_read_op
71   : public descriptor_read_op_base<MutableBufferSequence>
72 {
73 public:
74   ASIO_DEFINE_HANDLER_PTR(descriptor_read_op);
75 
descriptor_read_op(int descriptor,const MutableBufferSequence & buffers,Handler & handler)76   descriptor_read_op(int descriptor,
77       const MutableBufferSequence& buffers, Handler& handler)
78     : descriptor_read_op_base<MutableBufferSequence>(
79         descriptor, buffers, &descriptor_read_op::do_complete),
80       handler_(ASIO_MOVE_CAST(Handler)(handler))
81   {
82     handler_work<Handler>::start(handler_);
83   }
84 
do_complete(void * owner,operation * base,const asio::error_code &,std::size_t)85   static void do_complete(void* owner, operation* base,
86       const asio::error_code& /*ec*/,
87       std::size_t /*bytes_transferred*/)
88   {
89     // Take ownership of the handler object.
90     descriptor_read_op* o(static_cast<descriptor_read_op*>(base));
91     ptr p = { asio::detail::addressof(o->handler_), o, o };
92     handler_work<Handler> w(o->handler_);
93 
94     ASIO_HANDLER_COMPLETION((*o));
95 
96     // Make a copy of the handler so that the memory can be deallocated before
97     // the upcall is made. Even if we're not about to make an upcall, a
98     // sub-object of the handler may be the true owner of the memory associated
99     // with the handler. Consequently, a local copy of the handler is required
100     // to ensure that any owning sub-object remains valid until after we have
101     // deallocated the memory here.
102     detail::binder2<Handler, asio::error_code, std::size_t>
103       handler(o->handler_, o->ec_, o->bytes_transferred_);
104     p.h = asio::detail::addressof(handler.handler_);
105     p.reset();
106 
107     // Make the upcall if required.
108     if (owner)
109     {
110       fenced_block b(fenced_block::half);
111       ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_));
112       w.complete(handler, handler.handler_);
113       ASIO_HANDLER_INVOCATION_END;
114     }
115   }
116 
117 private:
118   Handler handler_;
119 };
120 
121 } // namespace detail
122 } // namespace asio
123 
124 #include "asio/detail/pop_options.hpp"
125 
126 #endif // !defined(ASIO_WINDOWS) && !defined(__CYGWIN__)
127 
128 #endif // ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP
129