1 // 2 // detail/descriptor_read_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_DESCRIPTOR_READ_OP_HPP 12 #define BOOST_ASIO_DETAIL_DESCRIPTOR_READ_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 20 #if !defined(BOOST_ASIO_WINDOWS) && !defined(__CYGWIN__) 21 22 #include <boost/asio/detail/bind_handler.hpp> 23 #include <boost/asio/detail/buffer_sequence_adapter.hpp> 24 #include <boost/asio/detail/descriptor_ops.hpp> 25 #include <boost/asio/detail/fenced_block.hpp> 26 #include <boost/asio/detail/handler_work.hpp> 27 #include <boost/asio/detail/memory.hpp> 28 #include <boost/asio/detail/reactor_op.hpp> 29 30 #include <boost/asio/detail/push_options.hpp> 31 32 namespace boost { 33 namespace asio { 34 namespace detail { 35 36 template <typename MutableBufferSequence> 37 class descriptor_read_op_base : public reactor_op 38 { 39 public: descriptor_read_op_base(const boost::system::error_code & success_ec,int descriptor,const MutableBufferSequence & buffers,func_type complete_func)40 descriptor_read_op_base(const boost::system::error_code& success_ec, 41 int descriptor, const MutableBufferSequence& buffers, 42 func_type complete_func) 43 : reactor_op(success_ec, 44 &descriptor_read_op_base::do_perform, complete_func), 45 descriptor_(descriptor), 46 buffers_(buffers) 47 { 48 } 49 do_perform(reactor_op * base)50 static status do_perform(reactor_op* base) 51 { 52 descriptor_read_op_base* o(static_cast<descriptor_read_op_base*>(base)); 53 54 typedef buffer_sequence_adapter<boost::asio::mutable_buffer, 55 MutableBufferSequence> bufs_type; 56 57 status result; 58 if (bufs_type::is_single_buffer) 59 { 60 result = descriptor_ops::non_blocking_read1(o->descriptor_, 61 bufs_type::first(o->buffers_).data(), 62 bufs_type::first(o->buffers_).size(), 63 o->ec_, o->bytes_transferred_) ? done : not_done; 64 } 65 else 66 { 67 bufs_type bufs(o->buffers_); 68 result = descriptor_ops::non_blocking_read(o->descriptor_, 69 bufs.buffers(), bufs.count(), o->ec_, o->bytes_transferred_) 70 ? done : not_done; 71 } 72 73 BOOST_ASIO_HANDLER_REACTOR_OPERATION((*o, "non_blocking_read", 74 o->ec_, o->bytes_transferred_)); 75 76 return result; 77 } 78 79 private: 80 int descriptor_; 81 MutableBufferSequence buffers_; 82 }; 83 84 template <typename MutableBufferSequence, typename Handler, typename IoExecutor> 85 class descriptor_read_op 86 : public descriptor_read_op_base<MutableBufferSequence> 87 { 88 public: 89 BOOST_ASIO_DEFINE_HANDLER_PTR(descriptor_read_op); 90 descriptor_read_op(const boost::system::error_code & success_ec,int descriptor,const MutableBufferSequence & buffers,Handler & handler,const IoExecutor & io_ex)91 descriptor_read_op(const boost::system::error_code& success_ec, 92 int descriptor, const MutableBufferSequence& buffers, 93 Handler& handler, const IoExecutor& io_ex) 94 : descriptor_read_op_base<MutableBufferSequence>(success_ec, 95 descriptor, buffers, &descriptor_read_op::do_complete), 96 handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler)), 97 work_(handler_, io_ex) 98 { 99 } 100 do_complete(void * owner,operation * base,const boost::system::error_code &,std::size_t)101 static void do_complete(void* owner, operation* base, 102 const boost::system::error_code& /*ec*/, 103 std::size_t /*bytes_transferred*/) 104 { 105 // Take ownership of the handler object. 106 descriptor_read_op* o(static_cast<descriptor_read_op*>(base)); 107 ptr p = { boost::asio::detail::addressof(o->handler_), o, o }; 108 109 BOOST_ASIO_HANDLER_COMPLETION((*o)); 110 111 // Take ownership of the operation's outstanding work. 112 handler_work<Handler, IoExecutor> w( 113 BOOST_ASIO_MOVE_CAST2(handler_work<Handler, IoExecutor>)( 114 o->work_)); 115 116 // Make a copy of the handler so that the memory can be deallocated before 117 // the upcall is made. Even if we're not about to make an upcall, a 118 // sub-object of the handler may be the true owner of the memory associated 119 // with the handler. Consequently, a local copy of the handler is required 120 // to ensure that any owning sub-object remains valid until after we have 121 // deallocated the memory here. 122 detail::binder2<Handler, boost::system::error_code, std::size_t> 123 handler(o->handler_, o->ec_, o->bytes_transferred_); 124 p.h = boost::asio::detail::addressof(handler.handler_); 125 p.reset(); 126 127 // Make the upcall if required. 128 if (owner) 129 { 130 fenced_block b(fenced_block::half); 131 BOOST_ASIO_HANDLER_INVOCATION_BEGIN((handler.arg1_, handler.arg2_)); 132 w.complete(handler, handler.handler_); 133 BOOST_ASIO_HANDLER_INVOCATION_END; 134 } 135 } 136 137 private: 138 Handler handler_; 139 handler_work<Handler, IoExecutor> work_; 140 }; 141 142 } // namespace detail 143 } // namespace asio 144 } // namespace boost 145 146 #include <boost/asio/detail/pop_options.hpp> 147 148 #endif // !defined(BOOST_ASIO_WINDOWS) && !defined(__CYGWIN__) 149 150 #endif // BOOST_ASIO_DETAIL_DESCRIPTOR_READ_OP_HPP 151