ceph/src/boost/boost/asio/detail/resolve_query_op.hpp

   1 //
   2 // detail/resolve_query_op.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 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_QUERY_OP_HPP
  12 #define BOOST_ASIO_DETAIL_RESOLVE_QUERY_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_context.hpp>
  21 #include <boost/asio/ip/basic_resolver_query.hpp>
  22 #include <boost/asio/ip/basic_resolver_results.hpp>
  23 #include <boost/asio/detail/bind_handler.hpp>
  24 #include <boost/asio/detail/fenced_block.hpp>
  25 #include <boost/asio/detail/handler_alloc_helpers.hpp>
  26 #include <boost/asio/detail/handler_invoke_helpers.hpp>
  27 #include <boost/asio/detail/memory.hpp>
  28 #include <boost/asio/detail/resolve_op.hpp>
  29 #include <boost/asio/detail/socket_ops.hpp>
  30
  31 #include <boost/asio/detail/push_options.hpp>
  32
  33 namespace boost {
  34 namespace asio {
  35 namespace detail {
  36
  37 template <typename Protocol, typename Handler>
  38 class resolve_query_op : public resolve_op
  39 {
  40 public:
  41   BOOST_ASIO_DEFINE_HANDLER_PTR(resolve_query_op);
  42
  43   typedef boost::asio::ip::basic_resolver_query<Protocol> query_type;
  44   typedef boost::asio::ip::basic_resolver_results<Protocol> results_type;
  45
  46   resolve_query_op(socket_ops::weak_cancel_token_type cancel_token,
  47       const query_type& query, io_context_impl& ioc, Handler& handler)
  48     : resolve_op(&resolve_query_op::do_complete),
  49       cancel_token_(cancel_token),
  50       query_(query),
  51       io_context_impl_(ioc),
  52       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
  53       addrinfo_(0)
  54   {
  55     handler_work<Handler>::start(handler_);
  56   }
  57
  58   ~resolve_query_op()
  59   {
  60     if (addrinfo_)
  61       socket_ops::freeaddrinfo(addrinfo_);
  62   }
  63
  64   static void do_complete(void* owner, operation* base,
  65       const boost::system::error_code& /*ec*/,
  66       std::size_t /*bytes_transferred*/)
  67   {
  68     // Take ownership of the operation object.
  69     resolve_query_op* o(static_cast<resolve_query_op*>(base));
  70     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
  71
  72     if (owner && owner != &o->io_context_impl_)
  73     {
  74       // The operation is being run on the worker io_context. Time to perform
  75       // the resolver operation.
  76
  77       // Perform the blocking host resolution operation.
  78       socket_ops::background_getaddrinfo(o->cancel_token_,
  79           o->query_.host_name().c_str(), o->query_.service_name().c_str(),
  80           o->query_.hints(), &o->addrinfo_, o->ec_);
  81
  82       // Pass operation back to main io_context for completion.
  83       o->io_context_impl_.post_deferred_completion(o);
  84       p.v = p.p = 0;
  85     }
  86     else
  87     {
  88       // The operation has been returned to the main io_context. The completion
  89       // handler is ready to be delivered.
  90
  91       // Take ownership of the operation's outstanding work.
  92       handler_work<Handler> w(o->handler_);
  93
  94       BOOST_ASIO_HANDLER_COMPLETION((*o));
  95
  96       // Make a copy of the handler so that the memory can be deallocated
  97       // before the upcall is made. Even if we're not about to make an upcall,
  98       // a sub-object of the handler may be the true owner of the memory
  99       // associated with the handler. Consequently, a local copy of the handler
 100       // is required to ensure that any owning sub-object remains valid until
 101       // after we have deallocated the memory here.
 102       detail::binder2<Handler, boost::system::error_code, results_type>
 103         handler(o->handler_, o->ec_, results_type());
 104       p.h = boost::asio::detail::addressof(handler.handler_);
 105       if (o->addrinfo_)
 106       {
 107         handler.arg2_ = results_type::create(o->addrinfo_,
 108             o->query_.host_name(), o->query_.service_name());
 109       }
 110       p.reset();
 111
 112       if (owner)
 113       {
 114         fenced_block b(fenced_block::half);
 115         BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
 116         w.complete(handler, handler.handler_);
 117         BOOST_ASIO_HANDLER_INVOCATION_END;
 118       }
 119     }
 120   }
 121
 122 private:
 123   socket_ops::weak_cancel_token_type cancel_token_;
 124   query_type query_;
 125   io_context_impl& io_context_impl_;
 126   Handler handler_;
 127   boost::asio::detail::addrinfo_type* addrinfo_;
 128 };
 129
 130 } // namespace detail
 131 } // namespace asio
 132 } // namespace boost
 133
 134 #include <boost/asio/detail/pop_options.hpp>
 135
 136 #endif // BOOST_ASIO_DETAIL_RESOLVE_QUERY_OP_HPP