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

   1 //
   2 // detail/resolve_query_op.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2020 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/detail/bind_handler.hpp>
  20 #include <boost/asio/detail/fenced_block.hpp>
  21 #include <boost/asio/detail/handler_alloc_helpers.hpp>
  22 #include <boost/asio/detail/handler_invoke_helpers.hpp>
  23 #include <boost/asio/detail/handler_work.hpp>
  24 #include <boost/asio/detail/memory.hpp>
  25 #include <boost/asio/detail/resolve_op.hpp>
  26 #include <boost/asio/detail/socket_ops.hpp>
  27 #include <boost/asio/error.hpp>
  28 #include <boost/asio/ip/basic_resolver_query.hpp>
  29 #include <boost/asio/ip/basic_resolver_results.hpp>
  30
  31 #if defined(BOOST_ASIO_HAS_IOCP)
  32 # include <boost/asio/detail/win_iocp_io_context.hpp>
  33 #else // defined(BOOST_ASIO_HAS_IOCP)
  34 # include <boost/asio/detail/scheduler.hpp>
  35 #endif // defined(BOOST_ASIO_HAS_IOCP)
  36
  37 #include <boost/asio/detail/push_options.hpp>
  38
  39 namespace boost {
  40 namespace asio {
  41 namespace detail {
  42
  43 template <typename Protocol, typename Handler, typename IoExecutor>
  44 class resolve_query_op : public resolve_op
  45 {
  46 public:
  47   BOOST_ASIO_DEFINE_HANDLER_PTR(resolve_query_op);
  48
  49   typedef boost::asio::ip::basic_resolver_query<Protocol> query_type;
  50   typedef boost::asio::ip::basic_resolver_results<Protocol> results_type;
  51
  52 #if defined(BOOST_ASIO_HAS_IOCP)
  53   typedef class win_iocp_io_context scheduler_impl;
  54 #else
  55   typedef class scheduler scheduler_impl;
  56 #endif
  57
  58   resolve_query_op(socket_ops::weak_cancel_token_type cancel_token,
  59       const query_type& qry, scheduler_impl& sched,
  60       Handler& handler, const IoExecutor& io_ex)
  61     : resolve_op(&resolve_query_op::do_complete),
  62       cancel_token_(cancel_token),
  63       query_(qry),
  64       scheduler_(sched),
  65       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)),
  66       work_(handler_, io_ex),
  67       addrinfo_(0)
  68   {
  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       BOOST_ASIO_HANDLER_COMPLETION((*o));
 105
 106       // Take ownership of the operation's outstanding work.
 107       handler_work<Handler, IoExecutor> w(
 108           BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)(
 109             o->work_));
 110
 111       // Make a copy of the handler so that the memory can be deallocated
 112       // before the upcall is made. Even if we're not about to make an upcall,
 113       // a sub-object of the handler may be the true owner of the memory
 114       // associated with the handler. Consequently, a local copy of the handler
 115       // is required to ensure that any owning sub-object remains valid until
 116       // after we have deallocated the memory here.
 117       detail::binder2<Handler, boost::system::error_code, results_type>
 118         handler(o->handler_, o->ec_, results_type());
 119       p.h = boost::asio::detail::addressof(handler.handler_);
 120       if (o->addrinfo_)
 121       {
 122         handler.arg2_ = results_type::create(o->addrinfo_,
 123             o->query_.host_name(), o->query_.service_name());
 124       }
 125       p.reset();
 126
 127       if (owner)
 128       {
 129         fenced_block b(fenced_block::half);
 130         BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
 131         w.complete(handler, handler.handler_);
 132         BOOST_ASIO_HANDLER_INVOCATION_END;
 133       }
 134     }
 135   }
 136
 137 private:
 138   socket_ops::weak_cancel_token_type cancel_token_;
 139   query_type query_;
 140   scheduler_impl& scheduler_;
 141   Handler handler_;
 142   handler_work<Handler, IoExecutor> work_;
 143   boost::asio::detail::addrinfo_type* addrinfo_;
 144 };
 145
 146 } // namespace detail
 147 } // namespace asio
 148 } // namespace boost
 149
 150 #include <boost/asio/detail/pop_options.hpp>
 151
 152 #endif // BOOST_ASIO_DETAIL_RESOLVE_QUERY_OP_HPP