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1  //
2  // detail/resolve_endpoint_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 ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP
12  #define ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP
13  
14  
15  #include "asio/detail/config.hpp"
16  #include "asio/error.hpp"
17  #include "asio/io_service.hpp"
18  #include "asio/ip/basic_resolver_iterator.hpp"
19  #include "asio/detail/addressof.hpp"
20  #include "asio/detail/bind_handler.hpp"
21  #include "asio/detail/fenced_block.hpp"
22  #include "asio/detail/handler_alloc_helpers.hpp"
23  #include "asio/detail/handler_invoke_helpers.hpp"
24  #include "asio/detail/operation.hpp"
25  #include "asio/detail/socket_ops.hpp"
26  
27  #include "asio/detail/push_options.hpp"
28  
29  namespace asio {
30  namespace detail {
31  
32  template <typename Protocol, typename Handler>
33  class resolve_endpoint_op : public operation
34  {
35  public:
36    ASIO_DEFINE_HANDLER_PTR(resolve_endpoint_op);
37  
38    typedef typename Protocol::endpoint endpoint_type;
39    typedef asio::ip::basic_resolver_iterator<Protocol> iterator_type;
40  
resolve_endpoint_op(socket_ops::weak_cancel_token_type cancel_token,const endpoint_type & endpoint,io_service_impl & ios,Handler & handler)41    resolve_endpoint_op(socket_ops::weak_cancel_token_type cancel_token,
42        const endpoint_type& endpoint, io_service_impl& ios, Handler& handler)
43      : operation(&resolve_endpoint_op::do_complete),
44        cancel_token_(cancel_token),
45        endpoint_(endpoint),
46        io_service_impl_(ios),
47        handler_(ASIO_MOVE_CAST(Handler)(handler))
48    {
49    }
50  
do_complete(io_service_impl * owner,operation * base,const asio::error_code &,std::size_t)51    static void do_complete(io_service_impl* owner, operation* base,
52        const asio::error_code& /*ec*/,
53        std::size_t /*bytes_transferred*/)
54    {
55      // Take ownership of the operation object.
56      resolve_endpoint_op* o(static_cast<resolve_endpoint_op*>(base));
57      ptr p = { asio::detail::addressof(o->handler_), o, o };
58  
59      if (owner && owner != &o->io_service_impl_)
60      {
61        // The operation is being run on the worker io_service. Time to perform
62        // the resolver operation.
63  
64        // Perform the blocking endpoint resolution operation.
65        char host_name[NI_MAXHOST];
66        char service_name[NI_MAXSERV];
67        socket_ops::background_getnameinfo(o->cancel_token_, o->endpoint_.data(),
68            o->endpoint_.size(), host_name, NI_MAXHOST, service_name, NI_MAXSERV,
69            o->endpoint_.protocol().type(), o->ec_);
70        o->iter_ = iterator_type::create(o->endpoint_, host_name, service_name);
71  
72        // Pass operation back to main io_service for completion.
73        o->io_service_impl_.post_deferred_completion(o);
74        p.v = p.p = 0;
75      }
76      else
77      {
78        // The operation has been returned to the main io_service. The completion
79        // handler is ready to be delivered.
80  
81        ASIO_HANDLER_COMPLETION((o));
82  
83        // Make a copy of the handler so that the memory can be deallocated
84        // before the upcall is made. Even if we're not about to make an upcall,
85        // a sub-object of the handler may be the true owner of the memory
86        // associated with the handler. Consequently, a local copy of the handler
87        // is required to ensure that any owning sub-object remains valid until
88        // after we have deallocated the memory here.
89        detail::binder2<Handler, asio::error_code, iterator_type>
90          handler(o->handler_, o->ec_, o->iter_);
91        p.h = asio::detail::addressof(handler.handler_);
92        p.reset();
93  
94        if (owner)
95        {
96          fenced_block b(fenced_block::half);
97          ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
98          asio_handler_invoke_helpers::invoke(handler, handler.handler_);
99          ASIO_HANDLER_INVOCATION_END;
100        }
101      }
102    }
103  
104  private:
105    socket_ops::weak_cancel_token_type cancel_token_;
106    endpoint_type endpoint_;
107    io_service_impl& io_service_impl_;
108    Handler handler_;
109    asio::error_code ec_;
110    iterator_type iter_;
111  };
112  
113  } // namespace detail
114  } // namespace asio
115  
116  #include "asio/detail/pop_options.hpp"
117  
118  #endif // ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP
119