1//
2// detail/resolver_service_base.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_RESOLVER_SERVICE_BASE_HPP
12#define BOOST_ASIO_DETAIL_RESOLVER_SERVICE_BASE_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/detail/mutex.hpp>
22#include <boost/asio/detail/noncopyable.hpp>
23#include <boost/asio/detail/operation.hpp>
24#include <boost/asio/detail/socket_ops.hpp>
25#include <boost/asio/detail/socket_types.hpp>
26#include <boost/asio/detail/scoped_ptr.hpp>
27#include <boost/asio/detail/thread.hpp>
28
29#include <boost/asio/detail/push_options.hpp>
30
31namespace boost {
32namespace asio {
33namespace detail {
34
35class resolver_service_base
36{
37public:
38 // The implementation type of the resolver. A cancellation token is used to
39 // indicate to the background thread that the operation has been cancelled.
40 typedef socket_ops::shared_cancel_token_type implementation_type;
41
42 // Constructor.
43 BOOST_ASIO_DECL resolver_service_base(boost::asio::io_service& io_service);
44
45 // Destructor.
46 BOOST_ASIO_DECL ~resolver_service_base();
47
48 // Destroy all user-defined handler objects owned by the service.
49 BOOST_ASIO_DECL void shutdown_service();
50
51 // Perform any fork-related housekeeping.
52 BOOST_ASIO_DECL void fork_service(
53 boost::asio::io_service::fork_event fork_ev);
54
55 // Construct a new resolver implementation.
56 BOOST_ASIO_DECL void construct(implementation_type& impl);
57
58 // Destroy a resolver implementation.
59 BOOST_ASIO_DECL void destroy(implementation_type&);
60
61 // Cancel pending asynchronous operations.
62 BOOST_ASIO_DECL void cancel(implementation_type& impl);
63
64protected:
65 // Helper function to start an asynchronous resolve operation.
66 BOOST_ASIO_DECL void start_resolve_op(operation* op);
67
68#if !defined(BOOST_ASIO_WINDOWS_RUNTIME)
69 // Helper class to perform exception-safe cleanup of addrinfo objects.
70 class auto_addrinfo
71 : private boost::asio::detail::noncopyable
72 {
73 public:
74 explicit auto_addrinfo(boost::asio::detail::addrinfo_type* ai)
75 : ai_(ai)
76 {
77 }
78
79 ~auto_addrinfo()
80 {
81 if (ai_)
82 socket_ops::freeaddrinfo(ai: ai_);
83 }
84
85 operator boost::asio::detail::addrinfo_type*()
86 {
87 return ai_;
88 }
89
90 private:
91 boost::asio::detail::addrinfo_type* ai_;
92 };
93#endif // !defined(BOOST_ASIO_WINDOWS_RUNTIME)
94
95 // Helper class to run the work io_service in a thread.
96 class work_io_service_runner;
97
98 // Start the work thread if it's not already running.
99 BOOST_ASIO_DECL void start_work_thread();
100
101 // The io_service implementation used to post completions.
102 io_service_impl& io_service_impl_;
103
104private:
105 // Mutex to protect access to internal data.
106 boost::asio::detail::mutex mutex_;
107
108 // Private io_service used for performing asynchronous host resolution.
109 boost::asio::detail::scoped_ptr<boost::asio::io_service> work_io_service_;
110
111 // The work io_service implementation used to post completions.
112 io_service_impl& work_io_service_impl_;
113
114 // Work for the private io_service to perform.
115 boost::asio::detail::scoped_ptr<boost::asio::io_service::work> work_;
116
117 // Thread used for running the work io_service's run loop.
118 boost::asio::detail::scoped_ptr<boost::asio::detail::thread> work_thread_;
119};
120
121} // namespace detail
122} // namespace asio
123} // namespace boost
124
125#include <boost/asio/detail/pop_options.hpp>
126
127#if defined(BOOST_ASIO_HEADER_ONLY)
128# include <boost/asio/detail/impl/resolver_service_base.ipp>
129#endif // defined(BOOST_ASIO_HEADER_ONLY)
130
131#endif // BOOST_ASIO_DETAIL_RESOLVER_SERVICE_BASE_HPP
132

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