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weak_ptr.hpp in vendors/XIOS/current/extern/boost/include/boost/smart_ptr – NEMO

source: vendors/XIOS/current/extern/boost/include/boost/smart_ptr/weak_ptr.hpp @ 3408

Last change on this file since 3408 was 3408, checked in by rblod, 12 years ago

importing initial XIOS vendor drop

  • Property svn:keywords set to Id
File size: 5.1 KB
Line 
1#ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED
2#define BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED
3
4//
5//  weak_ptr.hpp
6//
7//  Copyright (c) 2001, 2002, 2003 Peter Dimov
8//
9// Distributed under the Boost Software License, Version 1.0. (See
10// accompanying file LICENSE_1_0.txt or copy at
11// http://www.boost.org/LICENSE_1_0.txt)
12//
13//  See http://www.boost.org/libs/smart_ptr/weak_ptr.htm for documentation.
14//
15
16#include <memory> // boost.TR1 include order fix
17#include <boost/smart_ptr/detail/shared_count.hpp>
18#include <boost/smart_ptr/shared_ptr.hpp>
19
20#ifdef BOOST_MSVC  // moved here to work around VC++ compiler crash
21# pragma warning(push)
22# pragma warning(disable:4284) // odd return type for operator->
23#endif
24
25namespace boost
26{
27
28template<class T> class weak_ptr
29{
30private:
31
32    // Borland 5.5.1 specific workarounds
33    typedef weak_ptr<T> this_type;
34
35public:
36
37    typedef T element_type;
38
39    weak_ptr(): px(0), pn() // never throws in 1.30+
40    {
41    }
42
43//  generated copy constructor, assignment, destructor are fine
44
45
46//
47//  The "obvious" converting constructor implementation:
48//
49//  template<class Y>
50//  weak_ptr(weak_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws
51//  {
52//  }
53//
54//  has a serious problem.
55//
56//  r.px may already have been invalidated. The px(r.px)
57//  conversion may require access to *r.px (virtual inheritance).
58//
59//  It is not possible to avoid spurious access violations since
60//  in multithreaded programs r.px may be invalidated at any point.
61//
62
63    template<class Y>
64#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
65
66    weak_ptr( weak_ptr<Y> const & r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() )
67
68#else
69
70    weak_ptr( weak_ptr<Y> const & r )
71
72#endif
73    : px(r.lock().get()), pn(r.pn) // never throws
74    {
75    }
76
77#if defined( BOOST_HAS_RVALUE_REFS )
78
79    template<class Y>
80#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
81
82    weak_ptr( weak_ptr<Y> && r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() )
83
84#else
85
86    weak_ptr( weak_ptr<Y> && r )
87
88#endif
89    : px( r.lock().get() ), pn( static_cast< boost::detail::weak_count && >( r.pn ) ) // never throws
90    {
91        r.px = 0;
92    }
93
94    // for better efficiency in the T == Y case
95    weak_ptr( weak_ptr && r ): px( r.px ), pn( static_cast< boost::detail::weak_count && >( r.pn ) ) // never throws
96    {
97        r.px = 0;
98    }
99
100    // for better efficiency in the T == Y case
101    weak_ptr & operator=( weak_ptr && r ) // never throws
102    {
103        this_type( static_cast< weak_ptr && >( r ) ).swap( *this );
104        return *this;
105    }
106
107
108#endif
109
110    template<class Y>
111#if !defined( BOOST_SP_NO_SP_CONVERTIBLE )
112
113    weak_ptr( shared_ptr<Y> const & r, typename boost::detail::sp_enable_if_convertible<Y,T>::type = boost::detail::sp_empty() )
114
115#else
116
117    weak_ptr( shared_ptr<Y> const & r )
118
119#endif
120    : px( r.px ), pn( r.pn ) // never throws
121    {
122    }
123
124#if !defined(BOOST_MSVC) || (BOOST_MSVC >= 1300)
125
126    template<class Y>
127    weak_ptr & operator=(weak_ptr<Y> const & r) // never throws
128    {
129        px = r.lock().get();
130        pn = r.pn;
131        return *this;
132    }
133
134#if defined( BOOST_HAS_RVALUE_REFS )
135
136    template<class Y>
137    weak_ptr & operator=( weak_ptr<Y> && r )
138    {
139        this_type( static_cast< weak_ptr<Y> && >( r ) ).swap( *this );
140        return *this;
141    }
142
143#endif
144
145    template<class Y>
146    weak_ptr & operator=(shared_ptr<Y> const & r) // never throws
147    {
148        px = r.px;
149        pn = r.pn;
150        return *this;
151    }
152
153#endif
154
155    shared_ptr<T> lock() const // never throws
156    {
157        return shared_ptr<element_type>( *this, boost::detail::sp_nothrow_tag() );
158    }
159
160    long use_count() const // never throws
161    {
162        return pn.use_count();
163    }
164
165    bool expired() const // never throws
166    {
167        return pn.use_count() == 0;
168    }
169
170    bool _empty() const // extension, not in std::weak_ptr
171    {
172        return pn.empty();
173    }
174
175    void reset() // never throws in 1.30+
176    {
177        this_type().swap(*this);
178    }
179
180    void swap(this_type & other) // never throws
181    {
182        std::swap(px, other.px);
183        pn.swap(other.pn);
184    }
185
186    void _internal_assign(T * px2, boost::detail::shared_count const & pn2)
187    {
188        px = px2;
189        pn = pn2;
190    }
191
192    template<class Y> bool _internal_less(weak_ptr<Y> const & rhs) const
193    {
194        return pn < rhs.pn;
195    }
196
197// Tasteless as this may seem, making all members public allows member templates
198// to work in the absence of member template friends. (Matthew Langston)
199
200#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
201
202private:
203
204    template<class Y> friend class weak_ptr;
205    template<class Y> friend class shared_ptr;
206
207#endif
208
209    T * px;                       // contained pointer
210    boost::detail::weak_count pn; // reference counter
211
212};  // weak_ptr
213
214template<class T, class U> inline bool operator<(weak_ptr<T> const & a, weak_ptr<U> const & b)
215{
216    return a._internal_less(b);
217}
218
219template<class T> void swap(weak_ptr<T> & a, weak_ptr<T> & b)
220{
221    a.swap(b);
222}
223
224} // namespace boost
225
226#ifdef BOOST_MSVC
227# pragma warning(pop)
228#endif   
229
230#endif  // #ifndef BOOST_SMART_PTR_WEAK_PTR_HPP_INCLUDED
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