libstdc++
safe_unordered_base.h
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1 // Safe container/iterator base implementation -*- C++ -*-
2 
3 // Copyright (C) 2011 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file debug/safe_unordered_base.h
26  * This file is a GNU debug extension to the Standard C++ Library.
27  */
28 
29 #ifndef _GLIBCXX_DEBUG_SAFE_UNORDERED_BASE_H
30 #define _GLIBCXX_DEBUG_SAFE_UNORDERED_BASE_H 1
31 
32 #include <debug/safe_base.h>
33 
34 namespace __gnu_debug
35 {
36  class _Safe_unordered_container_base;
37 
38  /** \brief Basic functionality for a @a safe iterator.
39  *
40  * The %_Safe_local_iterator_base base class implements the functionality
41  * of a safe local iterator that is not specific to a particular iterator
42  * type. It contains a pointer back to the container it references
43  * along with iterator version information and pointers to form a
44  * doubly-linked list of local iterators referenced by the container.
45  *
46  * This class must not perform any operations that can throw an
47  * exception, or the exception guarantees of derived iterators will
48  * be broken.
49  */
51  {
52  protected:
53  /** Initializes the iterator and makes it singular. */
55  { }
56 
57  /** Initialize the iterator to reference the container pointed to
58  * by @p __seq. @p __constant is true when we are initializing a
59  * constant local iterator, and false if it is a mutable local iterator.
60  * Note that @p __seq may be NULL, in which case the iterator will be
61  * singular. Otherwise, the iterator will reference @p __seq and
62  * be nonsingular.
63  */
64  _Safe_local_iterator_base(const _Safe_sequence_base* __seq, bool __constant)
65  { this->_M_attach(const_cast<_Safe_sequence_base*>(__seq), __constant); }
66 
67  /** Initializes the iterator to reference the same container that
68  @p __x does. @p __constant is true if this is a constant
69  iterator, and false if it is mutable. */
71  bool __constant)
72  { this->_M_attach(__x._M_sequence, __constant); }
73 
75  operator=(const _Safe_local_iterator_base&);
76 
77  explicit
79 
80  ~_Safe_local_iterator_base() { this->_M_detach(); }
81 
82  _Safe_unordered_container_base*
83  _M_get_container() const _GLIBCXX_NOEXCEPT;
84 
85  public:
86  /** Attaches this iterator to the given container, detaching it
87  * from whatever container it was attached to originally. If the
88  * new container is the NULL pointer, the iterator is left
89  * unattached.
90  */
91  void _M_attach(_Safe_sequence_base* __seq, bool __constant);
92 
93  /** Likewise, but not thread-safe. */
94  void _M_attach_single(_Safe_sequence_base* __seq, bool __constant) throw ();
95 
96  /** Detach the iterator for whatever container it is attached to,
97  * if any.
98  */
99  void _M_detach();
100 
101  /** Likewise, but not thread-safe. */
102  void _M_detach_single() throw ();
103  };
104 
105  /**
106  * @brief Base class that supports tracking of local iterators that
107  * reference an unordered container.
108  *
109  * The %_Safe_unordered_container_base class provides basic support for
110  * tracking iterators into an unordered container. Containers that track
111  * iterators must derived from %_Safe_unordered_container_base publicly, so
112  * that safe iterators (which inherit _Safe_iterator_base) can
113  * attach to them. This class contains four linked lists of
114  * iterators, one for constant iterators, one for mutable
115  * iterators, one for constant local iterators, one for mutable local
116  * iterators and a version number that allows very fast
117  * invalidation of all iterators that reference the container.
118  *
119  * This class must ensure that no operation on it may throw an
120  * exception, otherwise @a safe containers may fail to provide the
121  * exception-safety guarantees required by the C++ standard.
122  */
124  {
125  typedef _Safe_sequence_base _Base;
126  public:
127  /// The list of mutable local iterators that reference this container
129 
130  /// The list of constant local iterators that reference this container
132 
133  protected:
134  // Initialize with a version number of 1 and no iterators
136  : _M_local_iterators(0), _M_const_local_iterators(0)
137  { }
138 
139  /** Notify all iterators that reference this container that the
140  container is being destroyed. */
142  { this->_M_detach_all(); }
143 
144  /** Detach all iterators, leaving them singular. */
145  void
146  _M_detach_all();
147 
148  /** Swap this container with the given container. This operation
149  * also swaps ownership of the iterators, so that when the
150  * operation is complete all iterators that originally referenced
151  * one container now reference the other container.
152  */
153  void
154  _M_swap(_Safe_unordered_container_base& __x);
155 
156  public:
157  /** Attach an iterator to this container. */
158  void
159  _M_attach_local(_Safe_iterator_base* __it, bool __constant);
160 
161  /** Likewise but not thread safe. */
162  void
163  _M_attach_local_single(_Safe_iterator_base* __it, bool __constant) throw ();
164 
165  /** Detach an iterator from this container */
166  void
167  _M_detach_local(_Safe_iterator_base* __it);
168 
169  /** Likewise but not thread safe. */
170  void
171  _M_detach_local_single(_Safe_iterator_base* __it) throw ();
172  };
173 } // namespace __gnu_debug
174 
175 #endif