libstdc++: safe_container.h Source File

libstdc++

safe_container.h
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1// Safe container implementation -*- C++ -*-
2
3// Copyright (C) 2014-2026 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
34namespace __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>
41 class _Safe_container
42 : public _SafeBase<_SafeContainer>
43 {
44 typedef _SafeBase<_SafeContainer> _Base;
45
46 _GLIBCXX20_CONSTEXPR
47 const _SafeContainer&
48 _M_cont() const _GLIBCXX_NOEXCEPT
49 { return *static_cast<const _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 void
60 _M_swap_base(const _Safe_container& __x) const noexcept
61 { _Base::_M_swap(__x); }
62
63 _GLIBCXX20_CONSTEXPR
64 _Safe_container(_Safe_container&& __x, const _Alloc&, std::true_type)
65 : _Safe_container(std::move(__x))
66 { }
67
68 _GLIBCXX20_CONSTEXPR
69 _Safe_container(_Safe_container&& __x, const _Alloc& __a, std::false_type)
70 : _Safe_container()
71 {
72 if (!std::__is_constant_evaluated())
73 {
74 if (__x._M_cont().get_allocator() == __a)
75 _M_swap_base(__x);
76 else
77 __x._M_invalidate_all();
78 }
79 }
80
81 protected:
82 _GLIBCXX20_CONSTEXPR
83 _Safe_container(_Safe_container&& __x, const _Alloc& __a)
84 : _Safe_container(std::move(__x), __a,
85 typename std::allocator_traits<_Alloc>::is_always_equal{})
86 { }
87#endif
88
89#if __cplusplus < 201103L
90 _Safe_container&
91 operator=(const _Safe_container& __x)
92 {
93 _Base::operator=(__x);
94 return *this;
95 }
96
97 void
98 _M_swap(const _Safe_container& __x) const throw()
99 { _Base::_M_swap(__x); }
100#else
101 _GLIBCXX20_CONSTEXPR
102 _Safe_container&
103 operator=(const _Safe_container&) noexcept = default;
104
105 _GLIBCXX20_CONSTEXPR
106 _Safe_container&
107 operator=(_Safe_container&& __x) noexcept
108 {
109 if (std::__is_constant_evaluated())
110 return *this;
111
112 if (std::__addressof(__x) == this)
113 {
114 // Standard containers have a valid but unspecified value after
115 // self-move, so we invalidate all debug iterators even if the
116 // underlying container happens to preserve its contents.
117 this->_M_invalidate_all();
118 return *this;
119 }
120
121 if (_IsCxx11AllocatorAware)
122 {
123 typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
124
125 bool __xfer_memory = _Alloc_traits::_S_propagate_on_move_assign()
126 || _M_cont().get_allocator() == __x._M_cont().get_allocator();
127 if (__xfer_memory)
128 _M_swap_base(__x);
129 else
130 this->_M_invalidate_all();
131 }
132 else
133 _M_swap_base(__x);
134
135 __x._M_invalidate_all();
136 return *this;
137 }
138
139 _GLIBCXX20_CONSTEXPR
140 void
141 _M_swap(const _Safe_container& __x) const noexcept
142 {
143 if (_IsCxx11AllocatorAware)
144 {
145 typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
146
147 if (!_Alloc_traits::_S_propagate_on_swap())
148 __glibcxx_check_equal_allocs(this->_M_cont()._M_base(),
149 __x._M_cont()._M_base());
150 }
151
152 _M_swap_base(__x);
153 }
154#endif
155 };
156
157} // namespace __gnu_debug
158
159#endif
std::true_type
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:119
std::false_type
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:122
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:138
std::__addressof
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition move.h:52
__gnu_debug
GNU debug classes for public use.
Definition boost_concept_check.h:60
std::allocator_traits::is_always_equal
typename __detected_or_t< is_empty< _Alloc >, __equal, _Alloc >::type is_always_equal
Whether all instances of the allocator type compare equal.
Definition bits/alloc_traits.h:372
__gnu_cxx::__alloc_traits
Uniform interface to C++98 and C++11 allocators.
Definition ext/alloc_traits.h:51
alloc_traits.h