libstdc++
safe_container.h
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1 // Safe container implementation -*- C++ -*-
2 
3 // Copyright (C) 2014-2025 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_container.h
26  * This file is a GNU debug extension to the Standard C++ Library.
27  */
28 
29 #ifndef _GLIBCXX_DEBUG_SAFE_CONTAINER_H
30 #define _GLIBCXX_DEBUG_SAFE_CONTAINER_H 1
31 
32 #include <ext/alloc_traits.h>
33 
34 namespace __gnu_debug
35 {
36  /// Safe class dealing with some allocator dependent operations.
37  template<typename _SafeContainer,
38  typename _Alloc,
39  template<typename> class _SafeBase,
40  bool _IsCxx11AllocatorAware = true>
42  : public _SafeBase<_SafeContainer>
43  {
44  typedef _SafeBase<_SafeContainer> _Base;
45 
46  _GLIBCXX20_CONSTEXPR
47  _SafeContainer&
48  _M_cont() _GLIBCXX_NOEXCEPT
49  { return *static_cast<_SafeContainer*>(this); }
50 
51  protected:
52 #if __cplusplus >= 201103L
53  _Safe_container() = default;
54  _Safe_container(const _Safe_container&) = default;
55  _Safe_container(_Safe_container&&) = default;
56 
57  private:
58  _GLIBCXX20_CONSTEXPR
59  _Safe_container(_Safe_container&& __x, const _Alloc&, std::true_type)
61  { }
62 
63  _GLIBCXX20_CONSTEXPR
64  _Safe_container(_Safe_container&& __x, const _Alloc& __a, std::false_type)
65  : _Safe_container()
66  {
67  if (!std::__is_constant_evaluated())
68  {
69  if (__x._M_cont().get_allocator() == __a)
70  _Base::_M_swap(__x);
71  else
72  __x._M_invalidate_all();
73  }
74  }
75 
76  protected:
77  _GLIBCXX20_CONSTEXPR
78  _Safe_container(_Safe_container&& __x, const _Alloc& __a)
79  : _Safe_container(std::move(__x), __a,
81  { }
82 #endif
83 
84  // Copy assignment invalidate all iterators.
85  _GLIBCXX20_CONSTEXPR
87  operator=(const _Safe_container&) _GLIBCXX_NOEXCEPT
88  {
89  if (!std::__is_constant_evaluated())
90  this->_M_invalidate_all();
91  return *this;
92  }
93 
94 #if __cplusplus >= 201103L
95  _GLIBCXX20_CONSTEXPR
97  operator=(_Safe_container&& __x) noexcept
98  {
99  if (std::__is_constant_evaluated())
100  return *this;
101 
102  if (std::__addressof(__x) == this)
103  {
104  // Standard containers have a valid but unspecified value after
105  // self-move, so we invalidate all debug iterators even if the
106  // underlying container happens to preserve its contents.
107  this->_M_invalidate_all();
108  return *this;
109  }
110 
111  if (_IsCxx11AllocatorAware)
112  {
113  typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
114 
115  bool __xfer_memory = _Alloc_traits::_S_propagate_on_move_assign()
116  || _M_cont().get_allocator() == __x._M_cont().get_allocator();
117  if (__xfer_memory)
118  _Base::_M_swap(__x);
119  else
120  this->_M_invalidate_all();
121  }
122  else
123  _Base::_M_swap(__x);
124 
125  __x._M_invalidate_all();
126  return *this;
127  }
128 
129  _GLIBCXX20_CONSTEXPR
130  void
131  _M_swap(_Safe_container& __x) noexcept
132  {
133  if (_IsCxx11AllocatorAware)
134  {
135  typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
136 
137  if (!_Alloc_traits::_S_propagate_on_swap())
138  __glibcxx_check_equal_allocs(this->_M_cont()._M_base(),
139  __x._M_cont()._M_base());
140  }
141 
142  _Base::_M_swap(__x);
143  }
144 #endif
145  };
146 
147 } // namespace __gnu_debug
148 
149 #endif
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:116
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:119
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:52
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:138
GNU debug classes for public use.
typename __detected_or_t< is_empty< _Alloc >, __equal, _Alloc >::type is_always_equal
Whether all instances of the allocator type compare equal.
Safe class dealing with some allocator dependent operations.
Uniform interface to C++98 and C++11 allocators.