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1 | #ifndef BOOST_ENABLE_SHARED_FROM_RAW_HPP_INCLUDED |
2 | #define BOOST_ENABLE_SHARED_FROM_RAW_HPP_INCLUDED | |
3 | ||
4 | // | |
5 | // enable_shared_from_raw.hpp | |
6 | // | |
7 | // Copyright 2002, 2009, 2014 Peter Dimov | |
8 | // Copyright 2008-2009 Frank Mori Hess | |
9 | // | |
10 | // Distributed under the Boost Software License, Version 1.0. | |
11 | // See accompanying file LICENSE_1_0.txt or copy at | |
12 | // http://www.boost.org/LICENSE_1_0.txt | |
13 | // | |
14 | ||
15 | #include <boost/config.hpp> | |
16 | #include <boost/shared_ptr.hpp> | |
17 | #include <boost/weak_ptr.hpp> | |
18 | #include <boost/assert.hpp> | |
19 | #include <boost/detail/workaround.hpp> | |
20 | ||
21 | namespace boost | |
22 | { | |
23 | template<typename T> boost::shared_ptr<T> shared_from_raw(T *); | |
24 | template<typename T> boost::weak_ptr<T> weak_from_raw(T *); | |
25 | ||
26 | namespace detail | |
27 | { | |
28 | template< class X, class Y > inline void sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe ); | |
29 | ||
30 | } // namespace detail | |
31 | ||
32 | class enable_shared_from_raw | |
33 | { | |
34 | protected: | |
35 | ||
36 | enable_shared_from_raw() | |
37 | { | |
38 | } | |
39 | ||
40 | enable_shared_from_raw( enable_shared_from_raw const & ) | |
41 | { | |
42 | } | |
43 | ||
44 | enable_shared_from_raw & operator=( enable_shared_from_raw const & ) | |
45 | { | |
46 | return *this; | |
47 | } | |
48 | ||
49 | ~enable_shared_from_raw() | |
50 | { | |
51 | BOOST_ASSERT( shared_this_.use_count() <= 1 ); // make sure no dangling shared_ptr objects exist | |
52 | } | |
53 | ||
54 | private: | |
55 | ||
56 | void init_if_expired() const | |
57 | { | |
58 | if( weak_this_.expired() ) | |
59 | { | |
60 | shared_this_.reset( static_cast<void*>(0), detail::esft2_deleter_wrapper() ); | |
61 | weak_this_ = shared_this_; | |
62 | } | |
63 | } | |
64 | ||
65 | void init_if_empty() const | |
66 | { | |
67 | if( weak_this_._empty() ) | |
68 | { | |
69 | shared_this_.reset( static_cast<void*>(0), detail::esft2_deleter_wrapper() ); | |
70 | weak_this_ = shared_this_; | |
71 | } | |
72 | } | |
73 | ||
74 | #ifdef BOOST_NO_MEMBER_TEMPLATE_FRIENDS | |
75 | public: | |
76 | #else | |
77 | private: | |
78 | template<class Y> friend class shared_ptr; | |
79 | template<typename T> friend boost::shared_ptr<T> shared_from_raw(T *); | |
80 | template<typename T> friend boost::weak_ptr<T> weak_from_raw(T *); | |
81 | template< class X, class Y > friend inline void detail::sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe ); | |
82 | #endif | |
83 | ||
84 | shared_ptr<void const volatile> shared_from_this() const | |
85 | { | |
86 | init_if_expired(); | |
87 | return shared_ptr<void const volatile>( weak_this_ ); | |
88 | } | |
89 | ||
90 | shared_ptr<void const volatile> shared_from_this() const volatile | |
91 | { | |
92 | return const_cast< enable_shared_from_raw const * >( this )->shared_from_this(); | |
93 | } | |
94 | ||
95 | weak_ptr<void const volatile> weak_from_this() const | |
96 | { | |
97 | init_if_empty(); | |
98 | return weak_this_; | |
99 | } | |
100 | ||
101 | weak_ptr<void const volatile> weak_from_this() const volatile | |
102 | { | |
103 | return const_cast< enable_shared_from_raw const * >( this )->weak_from_this(); | |
104 | } | |
105 | ||
106 | // Note: invoked automatically by shared_ptr; do not call | |
107 | template<class X, class Y> void _internal_accept_owner( shared_ptr<X> * ppx, Y * ) const | |
108 | { | |
109 | BOOST_ASSERT( ppx != 0 ); | |
110 | ||
111 | if( weak_this_.expired() ) | |
112 | { | |
113 | weak_this_ = *ppx; | |
114 | } | |
115 | else if( shared_this_.use_count() != 0 ) | |
116 | { | |
117 | BOOST_ASSERT( ppx->unique() ); // no weak_ptrs should exist either, but there's no way to check that | |
118 | ||
119 | detail::esft2_deleter_wrapper * pd = boost::get_deleter<detail::esft2_deleter_wrapper>( shared_this_ ); | |
120 | BOOST_ASSERT( pd != 0 ); | |
121 | ||
122 | pd->set_deleter( *ppx ); | |
123 | ||
124 | ppx->reset( shared_this_, ppx->get() ); | |
125 | shared_this_.reset(); | |
126 | } | |
127 | } | |
128 | ||
129 | mutable weak_ptr<void const volatile> weak_this_; | |
130 | ||
131 | private: | |
132 | ||
133 | mutable shared_ptr<void const volatile> shared_this_; | |
134 | }; | |
135 | ||
136 | template<typename T> | |
137 | boost::shared_ptr<T> shared_from_raw(T *p) | |
138 | { | |
139 | BOOST_ASSERT(p != 0); | |
140 | return boost::shared_ptr<T>(p->enable_shared_from_raw::shared_from_this(), p); | |
141 | } | |
142 | ||
143 | template<typename T> | |
144 | boost::weak_ptr<T> weak_from_raw(T *p) | |
145 | { | |
146 | BOOST_ASSERT(p != 0); | |
92f5a8d4 | 147 | boost::weak_ptr<T> result(p->enable_shared_from_raw::weak_from_this(), p); |
7c673cae FG |
148 | return result; |
149 | } | |
150 | ||
151 | namespace detail | |
152 | { | |
153 | template< class X, class Y > inline void sp_enable_shared_from_this( boost::shared_ptr<X> * ppx, Y const * py, boost::enable_shared_from_raw const * pe ) | |
154 | { | |
155 | if( pe != 0 ) | |
156 | { | |
157 | pe->_internal_accept_owner( ppx, const_cast< Y* >( py ) ); | |
158 | } | |
159 | } | |
160 | } // namepsace detail | |
161 | ||
162 | } // namespace boost | |
163 | ||
164 | #endif // #ifndef BOOST_ENABLE_SHARED_FROM_RAW_HPP_INCLUDED |