1 // Safe container implementation -*- C++ -*-
2
3 // Copyright (C) 2011-2023 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_container.h
26 * This file is a GNU debug extension to the Standard C++ Library.
27 */
28
29 #ifndef _GLIBCXX_DEBUG_SAFE_UNORDERED_CONTAINER_H
30 #define _GLIBCXX_DEBUG_SAFE_UNORDERED_CONTAINER_H 1
31
32 #include <debug/assertions.h>
33 #include <debug/macros.h>
34 #include <debug/functions.h>
35 #include <debug/safe_unordered_base.h>
36
37 namespace __gnu_debug
38 {
39 /**
40 * @brief Base class for constructing a @a safe unordered container type
41 * that tracks iterators that reference it.
42 *
43 * The class template %_Safe_unordered_container simplifies the
44 * construction of @a safe unordered containers that track the iterators
45 * that reference the container, so that the iterators are notified of
46 * changes in the container that may affect their operation, e.g., if
47 * the container invalidates its iterators or is destructed. This class
48 * template may only be used by deriving from it and passing the name
49 * of the derived class as its template parameter via the curiously
50 * recurring template pattern. The derived class must have @c
51 * iterator and @c const_iterator types that are instantiations of
52 * class template _Safe_iterator for this container and @c local_iterator
53 * and @c const_local_iterator types that are instantiations of class
54 * template _Safe_local_iterator for this container. Iterators will
55 * then be tracked automatically.
56 */
57 template<typename _Container>
58 class _Safe_unordered_container : public _Safe_unordered_container_base
59 {
60 private:
61 _Container&
62 _M_cont() noexcept
63 { return *static_cast<_Container*>(this); }
64
65 protected:
66 void
67 _M_invalidate_locals()
68 {
69 auto __local_end = _M_cont()._M_base().cend(0);
70 this->_M_invalidate_local_if(
71 [__local_end](__decltype(__local_end) __it)
72 { return __it != __local_end; });
73 }
74
75 #if __cplusplus > 201402L
76 template<typename _ExtractKey, typename _Source>
77 struct _UContInvalidatePred
78 {
79 template<typename _Iterator>
80 bool
81 operator()(_Iterator __it) const
82 { return _M_source.count(_ExtractKey{}(*__it)) == 0; }
83
84 const _Source& _M_source;
85 };
86
87 template<typename _ExtractKey, typename _Source>
88 struct _UMContInvalidatePred
89 {
90 template<typename _Iterator>
91 bool
92 operator()(_Iterator __it) const
93 {
94 auto __rng =
95 _M_source._M_base().equal_range(_ExtractKey{}(*__it));
96 for (auto __rit = __rng.first;
97 __rit != __rng.second; ++__rit)
98 {
99 if (__it == __rit)
100 return false;
101 }
102
103 return true;
104 }
105
106 const _Source& _M_source;
107 };
108
109 template<typename _Source, typename _InvalidatePred>
110 struct _UContMergeGuard
111 {
112 _UContMergeGuard(_Source& __src) noexcept
113 : _M_source(__src), _M_size(__src.size()), _M_pred { __src }
114 { }
115
116 _UContMergeGuard(const _UContMergeGuard&) = delete;
117
118 ~_UContMergeGuard()
119 {
120 const std::size_t __size = _M_source.size();
121 if (__size == _M_size)
122 return;
123
124 __try
125 {
126 if (__size == 0)
127 _M_source._M_invalidate_all();
128 else
129 {
130 _M_source._M_invalidate_if(_M_pred);
131 _M_source._M_invalidate_local_if(_M_pred);
132 }
133 }
134 __catch(...)
135 {
136 _M_source._M_invalidate_all();
137 }
138 }
139
140 _Source& _M_source;
141 const std::size_t _M_size;
142 _InvalidatePred _M_pred;
143 };
144
145 template<typename _ExtractKey, typename _Source>
146 static _UContMergeGuard<_Source,
147 _UContInvalidatePred<_ExtractKey, _Source>>
148 _S_uc_guard(_ExtractKey, _Source& __src)
149 {
150 typedef _UContInvalidatePred<_ExtractKey, _Source> _InvalidatePred;
151 return _UContMergeGuard<_Source, _InvalidatePred>(__src);
152 }
153
154 template<typename _ExtractKey, typename _Source>
155 static _UContMergeGuard<_Source,
156 _UMContInvalidatePred<_ExtractKey, _Source>>
157 _S_umc_guard(_ExtractKey, _Source& __src)
158 {
159 typedef _UMContInvalidatePred<_ExtractKey, _Source> _InvalidatePred;
160 return _UContMergeGuard<_Source, _InvalidatePred>(__src);
161 }
162 #endif // C++17
163
164 public:
165 void
166 _M_invalidate_all()
167 {
168 auto __end = _M_cont()._M_base().cend();
169 this->_M_invalidate_if([__end](__decltype(__end) __it)
170 { return __it != __end; });
171 _M_invalidate_locals();
172 }
173
174 /** Invalidates all iterators @c x that reference this container,
175 are not singular, and for which @c __pred(x) returns @c
176 true. @c __pred will be invoked with the normal iterators nested
177 in the safe ones. */
178 template<typename _Predicate>
179 void
180 _M_invalidate_if(_Predicate __pred);
181
182 /** Invalidates all local iterators @c x that reference this container,
183 are not singular, and for which @c __pred(x) returns @c
184 true. @c __pred will be invoked with the normal local iterators
185 nested in the safe ones. */
186 template<typename _Predicate>
187 void
188 _M_invalidate_local_if(_Predicate __pred);
189 };
190 } // namespace __gnu_debug
191
192 #include <debug/safe_unordered_container.tcc>
193
194 #endif