1 | // |
2 | // detail/completion_handler.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_COMPLETION_HANDLER_HPP |
12 | #define BOOST_ASIO_DETAIL_COMPLETION_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/addressof.hpp> |
19 | #include <boost/asio/detail/config.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/operation.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 completion_handler : public operation |
33 | { |
34 | public: |
35 | BOOST_ASIO_DEFINE_HANDLER_PTR(completion_handler); |
36 | |
37 | completion_handler(Handler& h) |
38 | : operation(&completion_handler::do_complete), |
39 | handler_(BOOST_ASIO_MOVE_CAST(Handler)(h)) |
40 | { |
41 | } |
42 | |
43 | static void do_complete(io_service_impl* owner, operation* base, |
44 | const boost::system::error_code& /*ec*/, |
45 | std::size_t /*bytes_transferred*/) |
46 | { |
47 | // Take ownership of the handler object. |
48 | completion_handler* h(static_cast<completion_handler*>(base)); |
49 | ptr p = { boost::asio::detail::addressof(h->handler_), h, h }; |
50 | |
51 | BOOST_ASIO_HANDLER_COMPLETION((h)); |
52 | |
53 | // Make a copy of the handler so that the memory can be deallocated before |
54 | // the upcall is made. Even if we're not about to make an upcall, a |
55 | // sub-object of the handler may be the true owner of the memory associated |
56 | // with the handler. Consequently, a local copy of the handler is required |
57 | // to ensure that any owning sub-object remains valid until after we have |
58 | // deallocated the memory here. |
59 | Handler handler(BOOST_ASIO_MOVE_CAST(Handler)(h->handler_)); |
60 | p.h = boost::asio::detail::addressof(handler); |
61 | p.reset(); |
62 | |
63 | // Make the upcall if required. |
64 | if (owner) |
65 | { |
66 | fenced_block b(fenced_block::half); |
67 | BOOST_ASIO_HANDLER_INVOCATION_BEGIN(()); |
68 | boost_asio_handler_invoke_helpers::invoke(handler, handler); |
69 | BOOST_ASIO_HANDLER_INVOCATION_END; |
70 | } |
71 | } |
72 | |
73 | private: |
74 | Handler handler_; |
75 | }; |
76 | |
77 | } // namespace detail |
78 | } // namespace asio |
79 | } // namespace boost |
80 | |
81 | #include <boost/asio/detail/pop_options.hpp> |
82 | |
83 | #endif // BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP |
84 | |