text: //
  // detail/winrt_resolve_op.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #ifndef BOOST_ASIO_DETAIL_WINRT_RESOLVE_OP_HPP
  #define BOOST_ASIO_DETAIL_WINRT_RESOLVE_OP_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include <boost/asio/detail/config.hpp>
  
  #if defined(BOOST_ASIO_WINDOWS_RUNTIME)
  
  #include <boost/asio/detail/bind_handler.hpp>
  #include <boost/asio/detail/fenced_block.hpp>
  #include <boost/asio/detail/handler_alloc_helpers.hpp>
  #include <boost/asio/detail/handler_invoke_helpers.hpp>
  #include <boost/asio/detail/memory.hpp>
  #include <boost/asio/detail/winrt_async_op.hpp>
  #include <boost/asio/ip/basic_resolver_results.hpp>
  #include <boost/asio/error.hpp>
  
  #include <boost/asio/detail/push_options.hpp>
  
  namespace boost {
  namespace asio {
  namespace detail {
  
  template <typename Protocol, typename Handler>
  class winrt_resolve_op :
    public winrt_async_op<
      Windows::Foundation::Collections::IVectorView<
        Windows::Networking::EndpointPair^>^>
  {
  public:
    BOOST_ASIO_DEFINE_HANDLER_PTR(winrt_resolve_op);
  
    typedef typename Protocol::endpoint endpoint_type;
    typedef boost::asio::ip::basic_resolver_query<Protocol> query_type;
    typedef boost::asio::ip::basic_resolver_results<Protocol> results_type;
  
    winrt_resolve_op(const query_type& query, Handler& handler)
      : winrt_async_op<
          Windows::Foundation::Collections::IVectorView<
            Windows::Networking::EndpointPair^>^>(
              &winrt_resolve_op::do_complete),
        query_(query),
        handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler))
    {
      handler_work<Handler>::start(handler_);
    }
  
    static void do_complete(void* owner, operation* base,
        const boost::system::error_code&, std::size_t)
    {
      // Take ownership of the operation object.
      winrt_resolve_op* o(static_cast<winrt_resolve_op*>(base));
      ptr p = { boost::asio::detail::addressof(o->handler_), o, o };
      handler_work<Handler> w(o->handler_);
  
      BOOST_ASIO_HANDLER_COMPLETION((*o));
  
      results_type results = results_type();
      if (!o->ec_)
      {
        try
        {
          results = results_type::create(o->result_, o->query_.hints(),
              o->query_.host_name(), o->query_.service_name());
        }
        catch (Platform::Exception^ e)
        {
          o->ec_ = boost::system::error_code(e->HResult,
              boost::system::system_category());
        }
      }
  
      // Make a copy of the handler so that the memory can be deallocated before
      // the upcall is made. Even if we're not about to make an upcall, a
      // sub-object of the handler may be the true owner of the memory associated
      // with the handler. Consequently, a local copy of the handler is required
      // to ensure that any owning sub-object remains valid until after we have
      // deallocated the memory here.
      detail::binder2<Handler, boost::system::error_code, results_type>
        handler(o->handler_, o->ec_, results);
      p.h = boost::asio::detail::addressof(handler.handler_);
      p.reset();
  
      // Make the upcall if required.
      if (owner)
      {
        fenced_block b(fenced_block::half);
        BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "..."));
        w.complete(handler, handler.handler_);
        BOOST_ASIO_HANDLER_INVOCATION_END;
      }
    }
  
  private:
    query_type query_;
    Handler handler_;
  };
  
  } // namespace detail
  } // namespace asio
  } // namespace boost
  
  #include <boost/asio/detail/pop_options.hpp>
  
  #endif // defined(BOOST_ASIO_WINDOWS_RUNTIME)
  
  #endif // BOOST_ASIO_DETAIL_WINRT_RESOLVE_OP_HPP
  