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1 | #ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED |
2 | #define BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED | |
3 | ||
4 | // | |
5 | // enable_shared_from_this.hpp | |
6 | // | |
7 | // Copyright 2002, 2009 Peter Dimov | |
8 | // | |
9 | // Distributed under the Boost Software License, Version 1.0. | |
10 | // See accompanying file LICENSE_1_0.txt or copy at | |
11 | // http://www.boost.org/LICENSE_1_0.txt | |
12 | // | |
13 | // http://www.boost.org/libs/smart_ptr/enable_shared_from_this.html | |
14 | // | |
15 | ||
16 | #include <boost/smart_ptr/weak_ptr.hpp> | |
17 | #include <boost/smart_ptr/shared_ptr.hpp> | |
18 | #include <boost/assert.hpp> | |
19 | #include <boost/config.hpp> | |
20 | ||
21 | namespace boost | |
22 | { | |
23 | ||
24 | template<class T> class enable_shared_from_this | |
25 | { | |
26 | protected: | |
27 | ||
28 | enable_shared_from_this() BOOST_NOEXCEPT | |
29 | { | |
30 | } | |
31 | ||
32 | enable_shared_from_this(enable_shared_from_this const &) BOOST_NOEXCEPT | |
33 | { | |
34 | } | |
35 | ||
36 | enable_shared_from_this & operator=(enable_shared_from_this const &) BOOST_NOEXCEPT | |
37 | { | |
38 | return *this; | |
39 | } | |
40 | ||
41 | ~enable_shared_from_this() BOOST_NOEXCEPT // ~weak_ptr<T> newer throws, so this call also must not throw | |
42 | { | |
43 | } | |
44 | ||
45 | public: | |
46 | ||
47 | shared_ptr<T> shared_from_this() | |
48 | { | |
49 | shared_ptr<T> p( weak_this_ ); | |
50 | BOOST_ASSERT( p.get() == this ); | |
51 | return p; | |
52 | } | |
53 | ||
54 | shared_ptr<T const> shared_from_this() const | |
55 | { | |
56 | shared_ptr<T const> p( weak_this_ ); | |
57 | BOOST_ASSERT( p.get() == this ); | |
58 | return p; | |
59 | } | |
60 | ||
61 | weak_ptr<T> weak_from_this() BOOST_NOEXCEPT | |
62 | { | |
63 | return weak_this_; | |
64 | } | |
65 | ||
66 | weak_ptr<T const> weak_from_this() const BOOST_NOEXCEPT | |
67 | { | |
68 | return weak_this_; | |
69 | } | |
70 | ||
71 | public: // actually private, but avoids compiler template friendship issues | |
72 | ||
73 | // Note: invoked automatically by shared_ptr; do not call | |
74 | template<class X, class Y> void _internal_accept_owner( shared_ptr<X> const * ppx, Y * py ) const | |
75 | { | |
76 | if( weak_this_.expired() ) | |
77 | { | |
78 | weak_this_ = shared_ptr<T>( *ppx, py ); | |
79 | } | |
80 | } | |
81 | ||
82 | private: | |
83 | ||
84 | mutable weak_ptr<T> weak_this_; | |
85 | }; | |
86 | ||
87 | } // namespace boost | |
88 | ||
89 | #endif // #ifndef BOOST_SMART_PTR_ENABLE_SHARED_FROM_THIS_HPP_INCLUDED |