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

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