// // completion_handler.hpp // ~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2010 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_COMPLETION_HANDLER_HPP #define BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/push_options.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/operation.hpp> namespace boost { namespace asio { namespace detail { template <typename Handler> class completion_handler : public operation { public: completion_handler(Handler h) : operation(&completion_handler::do_complete), handler_(h) { } static void do_complete(io_service_impl* owner, operation* base, boost::system::error_code /*ec*/, std::size_t /*bytes_transferred*/) { // Take ownership of the handler object. completion_handler* h(static_cast<completion_handler*>(base)); typedef handler_alloc_traits<Handler, completion_handler> alloc_traits; handler_ptr<alloc_traits> ptr(h->handler_, h); // Make the upcall if required. if (owner) { // 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. Handler handler(h->handler_); ptr.reset(); boost::asio::detail::fenced_block b; boost_asio_handler_invoke_helpers::invoke(handler, handler); } } private: Handler handler_; }; } // namespace detail } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP