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1 | // |
2 | // detail/completion_handler.hpp | |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
4 | // | |
b32b8144 | 5 | // Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
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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 | ||
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18 | #include <boost/asio/detail/config.hpp> |
19 | #include <boost/asio/detail/fenced_block.hpp> | |
20 | #include <boost/asio/detail/handler_alloc_helpers.hpp> | |
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21 | #include <boost/asio/detail/handler_work.hpp> |
22 | #include <boost/asio/detail/memory.hpp> | |
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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 | { | |
b32b8144 | 41 | handler_work<Handler>::start(handler_); |
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42 | } |
43 | ||
b32b8144 | 44 | static void do_complete(void* owner, operation* base, |
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45 | const boost::system::error_code& /*ec*/, |
46 | std::size_t /*bytes_transferred*/) | |
47 | { | |
48 | // Take ownership of the handler object. | |
49 | completion_handler* h(static_cast<completion_handler*>(base)); | |
50 | ptr p = { boost::asio::detail::addressof(h->handler_), h, h }; | |
b32b8144 | 51 | handler_work<Handler> w(h->handler_); |
7c673cae | 52 | |
b32b8144 | 53 | BOOST_ASIO_HANDLER_COMPLETION((*h)); |
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54 | |
55 | // Make a copy of the handler so that the memory can be deallocated before | |
56 | // the upcall is made. Even if we're not about to make an upcall, a | |
57 | // sub-object of the handler may be the true owner of the memory associated | |
58 | // with the handler. Consequently, a local copy of the handler is required | |
59 | // to ensure that any owning sub-object remains valid until after we have | |
60 | // deallocated the memory here. | |
61 | Handler handler(BOOST_ASIO_MOVE_CAST(Handler)(h->handler_)); | |
62 | p.h = boost::asio::detail::addressof(handler); | |
63 | p.reset(); | |
64 | ||
65 | // Make the upcall if required. | |
66 | if (owner) | |
67 | { | |
68 | fenced_block b(fenced_block::half); | |
69 | BOOST_ASIO_HANDLER_INVOCATION_BEGIN(()); | |
b32b8144 | 70 | w.complete(handler, handler); |
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71 | BOOST_ASIO_HANDLER_INVOCATION_END; |
72 | } | |
73 | } | |
74 | ||
75 | private: | |
76 | Handler handler_; | |
77 | }; | |
78 | ||
79 | } // namespace detail | |
80 | } // namespace asio | |
81 | } // namespace boost | |
82 | ||
83 | #include <boost/asio/detail/pop_options.hpp> | |
84 | ||
85 | #endif // BOOST_ASIO_DETAIL_COMPLETION_HANDLER_HPP |