1// Safe sequence implementation  -*- C++ -*-
2
3// Copyright (C) 2003, 2004, 2005, 2006
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 2, 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// You should have received a copy of the GNU General Public License along
18// with this library; see the file COPYING.  If not, write to the Free
19// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
20// USA.
21
22// As a special exception, you may use this file as part of a free software
23// library without restriction.  Specifically, if other files instantiate
24// templates or use macros or inline functions from this file, or you compile
25// this file and link it with other files to produce an executable, this
26// file does not by itself cause the resulting executable to be covered by
27// the GNU General Public License.  This exception does not however
28// invalidate any other reasons why the executable file might be covered by
29// the GNU General Public License.
30
31/** @file debug/safe_sequence.h
32 *  This file is a GNU debug extension to the Standard C++ Library.
33 */
34
35#ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
36#define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
37
38#include <debug/debug.h>
39#include <debug/macros.h>
40#include <debug/functions.h>
41#include <debug/safe_base.h>
42
43namespace __gnu_debug
44{
45  template<typename _Iterator, typename _Sequence>
46    class _Safe_iterator;
47
48  /** A simple function object that returns true if the passed-in
49   *  value is not equal to the stored value. It saves typing over
50   *  using both bind1st and not_equal.
51   */
52  template<typename _Type>
53    class _Not_equal_to
54    {
55      _Type __value;
56
57    public:
58      explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
59
60      bool
61      operator()(const _Type& __x) const
62      { return __value != __x; }
63    };
64
65  /** A function object that returns true when the given random access
66      iterator is at least @c n steps away from the given iterator. */
67  template<typename _Iterator>
68    class _After_nth_from
69    {
70      typedef typename std::iterator_traits<_Iterator>::difference_type
71      difference_type;
72
73      _Iterator _M_base;
74      difference_type _M_n;
75
76    public:
77      _After_nth_from(const difference_type& __n, const _Iterator& __base)
78      : _M_base(__base), _M_n(__n) { }
79
80      bool
81      operator()(const _Iterator& __x) const
82      { return __x - _M_base >= _M_n; }
83    };
84
85  /**
86   * @brief Base class for constructing a "safe" sequence type that
87   * tracks iterators that reference it.
88   *
89   * The class template %_Safe_sequence simplifies the construction of
90   * "safe" sequences that track the iterators that reference the
91   * sequence, so that the iterators are notified of changes in the
92   * sequence that may affect their operation, e.g., if the container
93   * invalidates its iterators or is destructed. This class template
94   * may only be used by deriving from it and passing the name of the
95   * derived class as its template parameter via the curiously
96   * recurring template pattern. The derived class must have @c
97   * iterator and @const_iterator types that are instantiations of
98   * class template _Safe_iterator for this sequence. Iterators will
99   * then be tracked automatically.
100   */
101  template<typename _Sequence>
102    class _Safe_sequence : public _Safe_sequence_base
103    {
104    public:
105      /** Invalidates all iterators @c x that reference this sequence,
106	  are not singular, and for which @c pred(x) returns @c
107	  true. The user of this routine should be careful not to make
108	  copies of the iterators passed to @p pred, as the copies may
109	  interfere with the invalidation. */
110      template<typename _Predicate>
111        void
112        _M_invalidate_if(_Predicate __pred);
113
114      /** Transfers all iterators that reference this memory location
115	  to this sequence from whatever sequence they are attached
116	  to. */
117      template<typename _Iterator>
118        void
119        _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x);
120    };
121
122  template<typename _Sequence>
123    template<typename _Predicate>
124      void
125      _Safe_sequence<_Sequence>::
126      _M_invalidate_if(_Predicate __pred)
127      {
128        typedef typename _Sequence::iterator iterator;
129        typedef typename _Sequence::const_iterator const_iterator;
130
131	__gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
132        for (_Safe_iterator_base* __iter = _M_iterators; __iter;)
133	  {
134	    iterator* __victim = static_cast<iterator*>(__iter);
135	    __iter = __iter->_M_next;
136	    if (!__victim->_M_singular())
137	      {
138		if (__pred(__victim->base()))
139		  __victim->_M_invalidate_single();
140	      }
141	  }
142
143        for (_Safe_iterator_base* __iter2 = _M_const_iterators; __iter2;)
144	  {
145	    const_iterator* __victim = static_cast<const_iterator*>(__iter2);
146	    __iter2 = __iter2->_M_next;
147	    if (!__victim->_M_singular())
148	      {
149		if (__pred(__victim->base()))
150		  __victim->_M_invalidate_single();
151	      }
152	  }
153      }
154
155  template<typename _Sequence>
156    template<typename _Iterator>
157      void
158      _Safe_sequence<_Sequence>::
159      _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x)
160      {
161	_Safe_sequence_base* __from = __x._M_sequence;
162	if (!__from)
163	  return;
164
165        typedef typename _Sequence::iterator iterator;
166        typedef typename _Sequence::const_iterator const_iterator;
167
168	__gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
169        for (_Safe_iterator_base* __iter = __from->_M_iterators; __iter;)
170	  {
171	    iterator* __victim = static_cast<iterator*>(__iter);
172	    __iter = __iter->_M_next;
173	    if (!__victim->_M_singular() && __victim->base() == __x.base())
174	      __victim->_M_attach_single(static_cast<_Sequence*>(this));
175	  }
176
177        for (_Safe_iterator_base* __iter2 = __from->_M_const_iterators;
178	     __iter2;)
179	  {
180	    const_iterator* __victim = static_cast<const_iterator*>(__iter2);
181	    __iter2 = __iter2->_M_next;
182	    if (!__victim->_M_singular() && __victim->base() == __x.base())
183	      __victim->_M_attach_single(static_cast<_Sequence*>(this));
184	  }
185      }
186} // namespace __gnu_debug
187
188#endif
189