1 /* 2 3 Copyright (c) 2017, Arvid Norberg 4 All rights reserved. 5 6 Redistribution and use in source and binary forms, with or without 7 modification, are permitted provided that the following conditions 8 are met: 9 10 * Redistributions of source code must retain the above copyright 11 notice, this list of conditions and the following disclaimer. 12 * Redistributions in binary form must reproduce the above copyright 13 notice, this list of conditions and the following disclaimer in 14 the documentation and/or other materials provided with the distribution. 15 * Neither the name of the author nor the names of its 16 contributors may be used to endorse or promote products derived 17 from this software without specific prior written permission. 18 19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 20 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 23 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 POSSIBILITY OF SUCH DAMAGE. 30 31 */ 32 33 #ifndef TORRENT_DEFERRED_HANDLER_HPP 34 #define TORRENT_DEFERRED_HANDLER_HPP 35 36 #include "libtorrent/assert.hpp" 37 #include "libtorrent/io_service.hpp" 38 39 namespace libtorrent { namespace aux { 40 41 template <typename Handler> 42 struct handler_wrapper 43 { handler_wrapperlibtorrent::aux::handler_wrapper44 handler_wrapper(bool& in_flight, Handler&& h) 45 : m_handler(std::move(h)) 46 , m_in_flight(in_flight) {} 47 template <typename... Args> operator ()libtorrent::aux::handler_wrapper48 void operator()(Args&&... a) 49 { 50 TORRENT_ASSERT(m_in_flight); 51 m_in_flight = false; 52 m_handler(std::forward<Args>(a)...); 53 } 54 55 // forward asio handler allocator to the underlying handler's asio_handler_allocate(std::size_t size,handler_wrapper<Handler> * h)56 friend void* asio_handler_allocate( 57 std::size_t size, handler_wrapper<Handler>* h) 58 { 59 return asio_handler_allocate(size, &h->m_handler); 60 } 61 asio_handler_deallocate(void * ptr,std::size_t size,handler_wrapper<Handler> * h)62 friend void asio_handler_deallocate( 63 void* ptr, std::size_t size, handler_wrapper<Handler>* h) 64 { 65 asio_handler_deallocate(ptr, size, &h->m_handler); 66 } 67 68 private: 69 Handler m_handler; 70 bool& m_in_flight; 71 }; 72 73 struct deferred_handler 74 { 75 template <typename Handler> postlibtorrent::aux::deferred_handler76 void post(io_service& ios, Handler&& h) 77 { 78 if (m_in_flight) return; 79 m_in_flight = true; 80 ios.post(handler_wrapper<Handler>(m_in_flight, std::forward<Handler>(h))); 81 } 82 private: 83 bool m_in_flight = false; 84 }; 85 86 }} 87 #endif 88