1//
2// detail/resolve_op.hpp
3// ~~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2015 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_RESOLVE_OP_HPP
12#define BOOST_ASIO_DETAIL_RESOLVE_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/error.hpp>
20#include <boost/asio/io_service.hpp>
21#include <boost/asio/ip/basic_resolver_iterator.hpp>
22#include <boost/asio/ip/basic_resolver_query.hpp>
23#include <boost/asio/detail/addressof.hpp>
24#include <boost/asio/detail/bind_handler.hpp>
25#include <boost/asio/detail/fenced_block.hpp>
26#include <boost/asio/detail/handler_alloc_helpers.hpp>
27#include <boost/asio/detail/handler_invoke_helpers.hpp>
28#include <boost/asio/detail/operation.hpp>
29#include <boost/asio/detail/socket_ops.hpp>
30
31#include <boost/asio/detail/push_options.hpp>
32
33namespace boost {
34namespace asio {
35namespace detail {
36
37template <typename Protocol, typename Handler>
38class resolve_op : public operation
39{
40public:
41 BOOST_ASIO_DEFINE_HANDLER_PTR(resolve_op);
42
43 typedef boost::asio::ip::basic_resolver_query<Protocol> query_type;
44 typedef boost::asio::ip::basic_resolver_iterator<Protocol> iterator_type;
45
46 resolve_op(socket_ops::weak_cancel_token_type cancel_token,
47 const query_type& query, io_service_impl& ios, Handler& handler)
48 : operation(&resolve_op::do_complete),
49 cancel_token_(cancel_token),
50 query_(query),
51 io_service_impl_(ios),
52 handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
53 addrinfo_(0)
54 {
55 }
56
57 ~resolve_op()
58 {
59 if (addrinfo_)
60 socket_ops::freeaddrinfo(ai: addrinfo_);
61 }
62
63 static void do_complete(io_service_impl* owner, operation* base,
64 const boost::system::error_code& /*ec*/,
65 std::size_t /*bytes_transferred*/)
66 {
67 // Take ownership of the operation object.
68 resolve_op* o(static_cast<resolve_op*>(base));
69 ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
70
71 if (owner && owner != &o->io_service_impl_)
72 {
73 // The operation is being run on the worker io_service. Time to perform
74 // the resolver operation.
75
76 // Perform the blocking host resolution operation.
77 socket_ops::background_getaddrinfo(cancel_token: o->cancel_token_,
78 host: o->query_.host_name().c_str(), service: o->query_.service_name().c_str(),
79 hints: o->query_.hints(), result: &o->addrinfo_, ec&: o->ec_);
80
81 // Pass operation back to main io_service for completion.
82 o->io_service_impl_.post_deferred_completion(o);
83 p.v = p.p = 0;
84 }
85 else
86 {
87 // The operation has been returned to the main io_service. The completion
88 // handler is ready to be delivered.
89
90 BOOST_ASIO_HANDLER_COMPLETION((o));
91
92 // Make a copy of the handler so that the memory can be deallocated
93 // before the upcall is made. Even if we're not about to make an upcall,
94 // a sub-object of the handler may be the true owner of the memory
95 // associated with the handler. Consequently, a local copy of the handler
96 // is required to ensure that any owning sub-object remains valid until
97 // after we have deallocated the memory here.
98 detail::binder2<Handler, boost::system::error_code, iterator_type>
99 handler(o->handler_, o->ec_, iterator_type());
100 p.h = boost::asio::detail::addressof(handler.handler_);
101 if (o->addrinfo_)
102 {
103 handler.arg2_ = iterator_type::create(o->addrinfo_,
104 o->query_.host_name(), o->query_.service_name());
105 }
106 p.reset();
107
108 if (owner)
109 {
110 fenced_block b(fenced_block::half);
111 BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
112 boost_asio_handler_invoke_helpers::invoke(handler, handler.handler_);
113 BOOST_ASIO_HANDLER_INVOCATION_END;
114 }
115 }
116 }
117
118private:
119 socket_ops::weak_cancel_token_type cancel_token_;
120 query_type query_;
121 io_service_impl& io_service_impl_;
122 Handler handler_;
123 boost::system::error_code ec_;
124 boost::asio::detail::addrinfo_type* addrinfo_;
125};
126
127} // namespace detail
128} // namespace asio
129} // namespace boost
130
131#include <boost/asio/detail/pop_options.hpp>
132
133#endif // BOOST_ASIO_DETAIL_RESOLVE_OP_HPP
134

source code of boost/boost/asio/detail/resolve_op.hpp