1 // 2 // detail/reactive_null_buffers_op.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2015 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_REACTIVE_NULL_BUFFERS_OP_HPP 12 #define BOOST_ASIO_DETAIL_REACTIVE_NULL_BUFFERS_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/addressof.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/reactor_op.hpp> 24 25 #include <boost/asio/detail/push_options.hpp> 26 27 namespace boost { 28 namespace asio { 29 namespace detail { 30 31 template <typename Handler> 32 class reactive_null_buffers_op : public reactor_op 33 { 34 public: 35 BOOST_ASIO_DEFINE_HANDLER_PTR(reactive_null_buffers_op); 36 reactive_null_buffers_op(Handler & handler)37 reactive_null_buffers_op(Handler& handler) 38 : reactor_op(&reactive_null_buffers_op::do_perform, 39 &reactive_null_buffers_op::do_complete), 40 handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)) 41 { 42 } 43 do_perform(reactor_op *)44 static bool do_perform(reactor_op*) 45 { 46 return true; 47 } 48 do_complete(io_service_impl * owner,operation * base,const boost::system::error_code &,std::size_t)49 static void do_complete(io_service_impl* owner, operation* base, 50 const boost::system::error_code& /*ec*/, 51 std::size_t /*bytes_transferred*/) 52 { 53 // Take ownership of the handler object. 54 reactive_null_buffers_op* o(static_cast<reactive_null_buffers_op*>(base)); 55 ptr p = { boost::asio::detail::addressof(o->handler_), o, o }; 56 57 BOOST_ASIO_HANDLER_COMPLETION((o)); 58 59 // Make a copy of the handler so that the memory can be deallocated before 60 // the upcall is made. Even if we're not about to make an upcall, a 61 // sub-object of the handler may be the true owner of the memory associated 62 // with the handler. Consequently, a local copy of the handler is required 63 // to ensure that any owning sub-object remains valid until after we have 64 // deallocated the memory here. 65 detail::binder2<Handler, boost::system::error_code, std::size_t> 66 handler(o->handler_, o->ec_, o->bytes_transferred_); 67 p.h = boost::asio::detail::addressof(handler.handler_); 68 p.reset(); 69 70 // Make the upcall if required. 71 if (owner) 72 { 73 fenced_block b(fenced_block::half); 74 BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_)); 75 boost_asio_handler_invoke_helpers::invoke(handler, handler.handler_); 76 BOOST_ASIO_HANDLER_INVOCATION_END; 77 } 78 } 79 80 private: 81 Handler handler_; 82 }; 83 84 } // namespace detail 85 } // namespace asio 86 } // namespace boost 87 88 #include <boost/asio/detail/pop_options.hpp> 89 90 #endif // BOOST_ASIO_DETAIL_REACTIVE_NULL_BUFFERS_OP_HPP 91