libstdc++
safe_sequence.h
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1 // Safe sequence implementation -*- C++ -*-
2 
3 // Copyright (C) 2003, 2004, 2005, 2006, 2009
4 // Free Software Foundation, Inc.
5 //
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
10 // any later version.
11 
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
16 
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
20 
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
25 
26 /** @file debug/safe_sequence.h
27  * This file is a GNU debug extension to the Standard C++ Library.
28  */
29 
30 #ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
31 #define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
32 
33 #include <debug/debug.h>
34 #include <debug/macros.h>
35 #include <debug/functions.h>
36 #include <debug/safe_base.h>
37 
38 namespace __gnu_debug
39 {
40  template<typename _Iterator, typename _Sequence>
41  class _Safe_iterator;
42 
43  /** A simple function object that returns true if the passed-in
44  * value is not equal to the stored value. It saves typing over
45  * using both bind1st and not_equal.
46  */
47  template<typename _Type>
49  {
50  _Type __value;
51 
52  public:
53  explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
54 
55  bool
56  operator()(const _Type& __x) const
57  { return __value != __x; }
58  };
59 
60  /** A function object that returns true when the given random access
61  iterator is at least @c n steps away from the given iterator. */
62  template<typename _Iterator>
64  {
65  typedef typename std::iterator_traits<_Iterator>::difference_type
66  difference_type;
67 
68  _Iterator _M_base;
69  difference_type _M_n;
70 
71  public:
72  _After_nth_from(const difference_type& __n, const _Iterator& __base)
73  : _M_base(__base), _M_n(__n) { }
74 
75  bool
76  operator()(const _Iterator& __x) const
77  { return __x - _M_base >= _M_n; }
78  };
79 
80  /**
81  * @brief Base class for constructing a "safe" sequence type that
82  * tracks iterators that reference it.
83  *
84  * The class template %_Safe_sequence simplifies the construction of
85  * "safe" sequences that track the iterators that reference the
86  * sequence, so that the iterators are notified of changes in the
87  * sequence that may affect their operation, e.g., if the container
88  * invalidates its iterators or is destructed. This class template
89  * may only be used by deriving from it and passing the name of the
90  * derived class as its template parameter via the curiously
91  * recurring template pattern. The derived class must have @c
92  * iterator and @const_iterator types that are instantiations of
93  * class template _Safe_iterator for this sequence. Iterators will
94  * then be tracked automatically.
95  */
96  template<typename _Sequence>
97  class _Safe_sequence : public _Safe_sequence_base
98  {
99  public:
100  /** Invalidates all iterators @c x that reference this sequence,
101  are not singular, and for which @c pred(x) returns @c
102  true. The user of this routine should be careful not to make
103  copies of the iterators passed to @p pred, as the copies may
104  interfere with the invalidation. */
105  template<typename _Predicate>
106  void
107  _M_invalidate_if(_Predicate __pred);
108 
109  /** Transfers all iterators that reference this memory location
110  to this sequence from whatever sequence they are attached
111  to. */
112  template<typename _Iterator>
113  void
115  };
116 
117  template<typename _Sequence>
118  template<typename _Predicate>
119  void
121  _M_invalidate_if(_Predicate __pred)
122  {
123  typedef typename _Sequence::iterator iterator;
124  typedef typename _Sequence::const_iterator const_iterator;
125 
126  __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
127  for (_Safe_iterator_base* __iter = _M_iterators; __iter;)
128  {
129  iterator* __victim = static_cast<iterator*>(__iter);
130  __iter = __iter->_M_next;
131  if (!__victim->_M_singular())
132  {
133  if (__pred(__victim->base()))
134  __victim->_M_invalidate_single();
135  }
136  }
137 
138  for (_Safe_iterator_base* __iter2 = _M_const_iterators; __iter2;)
139  {
140  const_iterator* __victim = static_cast<const_iterator*>(__iter2);
141  __iter2 = __iter2->_M_next;
142  if (!__victim->_M_singular())
143  {
144  if (__pred(__victim->base()))
145  __victim->_M_invalidate_single();
146  }
147  }
148  }
149 
150  template<typename _Sequence>
151  template<typename _Iterator>
152  void
155  {
156  _Safe_sequence_base* __from = __x._M_sequence;
157  if (!__from)
158  return;
159 
160  typedef typename _Sequence::iterator iterator;
161  typedef typename _Sequence::const_iterator const_iterator;
162 
163  __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
164  for (_Safe_iterator_base* __iter = __from->_M_iterators; __iter;)
165  {
166  iterator* __victim = static_cast<iterator*>(__iter);
167  __iter = __iter->_M_next;
168  if (!__victim->_M_singular() && __victim->base() == __x.base())
169  __victim->_M_attach_single(static_cast<_Sequence*>(this));
170  }
171 
172  for (_Safe_iterator_base* __iter2 = __from->_M_const_iterators;
173  __iter2;)
174  {
175  const_iterator* __victim = static_cast<const_iterator*>(__iter2);
176  __iter2 = __iter2->_M_next;
177  if (!__victim->_M_singular() && __victim->base() == __x.base())
178  __victim->_M_attach_single(static_cast<_Sequence*>(this));
179  }
180  }
181 } // namespace __gnu_debug
182 
183 #endif