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

   1 //
   2 // detail/resolve_query_op.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2019 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/ip/basic_resolver_query.hpp>
  21 #include <boost/asio/ip/basic_resolver_results.hpp>
  22 #include <boost/asio/detail/bind_handler.hpp>
  23 #include <boost/asio/detail/fenced_block.hpp>
  24 #include <boost/asio/detail/handler_alloc_helpers.hpp>
  25 #include <boost/asio/detail/handler_invoke_helpers.hpp>
  26 #include <boost/asio/detail/memory.hpp>
  27 #include <boost/asio/detail/resolve_op.hpp>
  28 #include <boost/asio/detail/socket_ops.hpp>
  29
  30 #if defined(BOOST_ASIO_HAS_IOCP)
  31 # include <boost/asio/detail/win_iocp_io_context.hpp>
  32 #else // defined(BOOST_ASIO_HAS_IOCP)
  33 # include <boost/asio/detail/scheduler.hpp>
  34 #endif // defined(BOOST_ASIO_HAS_IOCP)
  35
  36 #include <boost/asio/detail/push_options.hpp>
  37
  38 namespace boost {
  39 namespace asio {
  40 namespace detail {
  41
  42 template <typename Protocol, typename Handler, typename IoExecutor>
  43 class resolve_query_op : public resolve_op
  44 {
  45 public:
  46   BOOST_ASIO_DEFINE_HANDLER_PTR(resolve_query_op);
  47
  48   typedef boost::asio::ip::basic_resolver_query<Protocol> query_type;
  49   typedef boost::asio::ip::basic_resolver_results<Protocol> results_type;
  50
  51 #if defined(BOOST_ASIO_HAS_IOCP)
  52   typedef class win_iocp_io_context scheduler_impl;
  53 #else
  54   typedef class scheduler scheduler_impl;
  55 #endif
  56
  57   resolve_query_op(socket_ops::weak_cancel_token_type cancel_token,
  58       const query_type& query, scheduler_impl& sched,
  59       Handler& handler, const IoExecutor& io_ex)
  60     : resolve_op(&resolve_query_op::do_complete),
  61       cancel_token_(cancel_token),
  62       query_(query),
  63       scheduler_(sched),
  64       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
  65       io_executor_(io_ex),
  66       addrinfo_(0)
  67   {
  68     handler_work<Handler, IoExecutor>::start(handler_, io_executor_);
  69   }
  70
  71   ~resolve_query_op()
  72   {
  73     if (addrinfo_)
  74       socket_ops::freeaddrinfo(addrinfo_);
  75   }
  76
  77   static void do_complete(void* owner, operation* base,
  78       const boost::system::error_code& /*ec*/,
  79       std::size_t /*bytes_transferred*/)
  80   {
  81     // Take ownership of the operation object.
  82     resolve_query_op* o(static_cast<resolve_query_op*>(base));
  83     ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
  84
  85     if (owner && owner != &o->scheduler_)
  86     {
  87       // The operation is being run on the worker io_context. Time to perform
  88       // the resolver operation.
  89
  90       // Perform the blocking host resolution operation.
  91       socket_ops::background_getaddrinfo(o->cancel_token_,
  92           o->query_.host_name().c_str(), o->query_.service_name().c_str(),
  93           o->query_.hints(), &o->addrinfo_, o->ec_);
  94
  95       // Pass operation back to main io_context for completion.
  96       o->scheduler_.post_deferred_completion(o);
  97       p.v = p.p = 0;
  98     }
  99     else
 100     {
 101       // The operation has been returned to the main io_context. The completion
 102       // handler is ready to be delivered.
 103
 104       // Take ownership of the operation's outstanding work.
 105       handler_work<Handler, IoExecutor> w(o->handler_, o->io_executor_);
 106
 107       BOOST_ASIO_HANDLER_COMPLETION((*o));
 108
 109       // Make a copy of the handler so that the memory can be deallocated
 110       // before the upcall is made. Even if we're not about to make an upcall,
 111       // a sub-object of the handler may be the true owner of the memory
 112       // associated with the handler. Consequently, a local copy of the handler
 113       // is required to ensure that any owning sub-object remains valid until
 114       // after we have deallocated the memory here.
 115       detail::binder2<Handler, boost::system::error_code, results_type>
 116         handler(o->handler_, o->ec_, results_type());
 117       p.h = boost::asio::detail::addressof(handler.handler_);
 118       if (o->addrinfo_)
 119       {
 120         handler.arg2_ = results_type::create(o->addrinfo_,
 121             o->query_.host_name(), o->query_.service_name());
 122       }
 123       p.reset();
 124
 125       if (owner)
 126       {
 127         fenced_block b(fenced_block::half);
 128         BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
 129         w.complete(handler, handler.handler_);
 130         BOOST_ASIO_HANDLER_INVOCATION_END;
 131       }
 132     }
 133   }
 134
 135 private:
 136   socket_ops::weak_cancel_token_type cancel_token_;
 137   query_type query_;
 138   scheduler_impl& scheduler_;
 139   Handler handler_;
 140   IoExecutor io_executor_;
 141   boost::asio::detail::addrinfo_type* addrinfo_;
 142 };
 143
 144 } // namespace detail
 145 } // namespace asio
 146 } // namespace boost
 147
 148 #include <boost/asio/detail/pop_options.hpp>
 149
 150 #endif // BOOST_ASIO_DETAIL_RESOLVE_QUERY_OP_HPP