1 // 2 // detail/resolve_endpoint_op.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2021 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/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_results.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_endpoint_op : public resolve_op 44 { 45 public: 46 BOOST_ASIO_DEFINE_HANDLER_PTR(resolve_endpoint_op); 47 48 typedef typename Protocol::endpoint endpoint_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 resolve_endpoint_op(socket_ops::weak_cancel_token_type cancel_token,const endpoint_type & endpoint,scheduler_impl & sched,Handler & handler,const IoExecutor & io_ex)57 resolve_endpoint_op(socket_ops::weak_cancel_token_type cancel_token, 58 const endpoint_type& endpoint, scheduler_impl& sched, 59 Handler& handler, const IoExecutor& io_ex) 60 : resolve_op(&resolve_endpoint_op::do_complete), 61 cancel_token_(cancel_token), 62 endpoint_(endpoint), 63 scheduler_(sched), 64 handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)), 65 work_(handler_, io_ex) 66 { 67 } 68 do_complete(void * owner,operation * base,const boost::system::error_code &,std::size_t)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 BOOST_ASIO_HANDLER_COMPLETION((*o)); 100 101 // Take ownership of the operation's outstanding work. 102 handler_work<Handler, IoExecutor> w( 103 BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)( 104 o->work_)); 105 106 // Make a copy of the handler so that the memory can be deallocated 107 // before the upcall is made. Even if we're not about to make an upcall, 108 // a sub-object of the handler may be the true owner of the memory 109 // associated with the handler. Consequently, a local copy of the handler 110 // is required to ensure that any owning sub-object remains valid until 111 // after we have deallocated the memory here. 112 detail::binder2<Handler, boost::system::error_code, results_type> 113 handler(o->handler_, o->ec_, o->results_); 114 p.h = boost::asio::detail::addressof(handler.handler_); 115 p.reset(); 116 117 if (owner) 118 { 119 fenced_block b(fenced_block::half); 120 BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, "...")); 121 w.complete(handler, handler.handler_); 122 BOOST_ASIO_HANDLER_INVOCATION_END; 123 } 124 } 125 } 126 127 private: 128 socket_ops::weak_cancel_token_type cancel_token_; 129 endpoint_type endpoint_; 130 scheduler_impl& scheduler_; 131 Handler handler_; 132 handler_work<Handler, IoExecutor> work_; 133 results_type results_; 134 }; 135 136 } // namespace detail 137 } // namespace asio 138 } // namespace boost 139 140 #include <boost/asio/detail/pop_options.hpp> 141 142 #endif // BOOST_ASIO_DETAIL_RESOLVER_ENDPOINT_OP_HPP 143