1 // 2 // detail/wait_handler.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_WAIT_HANDLER_HPP 12 #define BOOST_ASIO_DETAIL_WAIT_HANDLER_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/fenced_block.hpp> 20 #include <boost/asio/detail/handler_alloc_helpers.hpp> 21 #include <boost/asio/detail/handler_invoke_helpers.hpp> 22 #include <boost/asio/detail/handler_work.hpp> 23 #include <boost/asio/detail/memory.hpp> 24 #include <boost/asio/detail/wait_op.hpp> 25 26 #include <boost/asio/detail/push_options.hpp> 27 28 namespace boost { 29 namespace asio { 30 namespace detail { 31 32 template <typename Handler, typename IoExecutor> 33 class wait_handler : public wait_op 34 { 35 public: 36 BOOST_ASIO_DEFINE_HANDLER_PTR(wait_handler); 37 wait_handler(Handler & h,const IoExecutor & ex)38 wait_handler(Handler& h, const IoExecutor& ex) 39 : wait_op(&wait_handler::do_complete), 40 handler_(BOOST_ASIO_MOVE_CAST(Handler)(h)), 41 io_executor_(ex) 42 { 43 handler_work<Handler, IoExecutor>::start(handler_, io_executor_); 44 } 45 do_complete(void * owner,operation * base,const boost::system::error_code &,std::size_t)46 static void do_complete(void* owner, operation* base, 47 const boost::system::error_code& /*ec*/, 48 std::size_t /*bytes_transferred*/) 49 { 50 // Take ownership of the handler object. 51 wait_handler* h(static_cast<wait_handler*>(base)); 52 ptr p = { boost::asio::detail::addressof(h->handler_), h, h }; 53 handler_work<Handler, IoExecutor> w(h->handler_, h->io_executor_); 54 55 BOOST_ASIO_HANDLER_COMPLETION((*h)); 56 57 // Make a copy of the handler so that the memory can be deallocated before 58 // the upcall is made. Even if we're not about to make an upcall, a 59 // sub-object of the handler may be the true owner of the memory associated 60 // with the handler. Consequently, a local copy of the handler is required 61 // to ensure that any owning sub-object remains valid until after we have 62 // deallocated the memory here. 63 detail::binder1<Handler, boost::system::error_code> 64 handler(h->handler_, h->ec_); 65 p.h = boost::asio::detail::addressof(handler.handler_); 66 p.reset(); 67 68 // Make the upcall if required. 69 if (owner) 70 { 71 fenced_block b(fenced_block::half); 72 BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_)); 73 w.complete(handler, handler.handler_); 74 BOOST_ASIO_HANDLER_INVOCATION_END; 75 } 76 } 77 78 private: 79 Handler handler_; 80 IoExecutor io_executor_; 81 }; 82 83 } // namespace detail 84 } // namespace asio 85 } // namespace boost 86 87 #include <boost/asio/detail/pop_options.hpp> 88 89 #endif // BOOST_ASIO_DETAIL_WAIT_HANDLER_HPP 90