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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 
     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 
     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