1 // Safe container implementation  -*- C++ -*-
2 
3 // Copyright (C) 2014-2022 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>
41     class _Safe_container
42     : public _SafeBase<_SafeContainer>
43     {
44       typedef _SafeBase<_SafeContainer> _Base;
45 
46       _SafeContainer&
_M_cont()47       _M_cont() _GLIBCXX_NOEXCEPT
48       { return *static_cast<_SafeContainer*>(this); }
49 
50     protected:
51 #if __cplusplus >= 201103L
52       _Safe_container() = default;
53       _Safe_container(const _Safe_container&) = default;
54       _Safe_container(_Safe_container&&) = default;
55 
56     private:
_Safe_container(_Safe_container && __x,const _Alloc &,std::true_type)57       _Safe_container(_Safe_container&& __x, const _Alloc&, std::true_type)
58       : _Safe_container(std::move(__x))
59       { }
60 
_Safe_container(_Safe_container && __x,const _Alloc & __a,std::false_type)61       _Safe_container(_Safe_container&& __x, const _Alloc& __a, std::false_type)
62       : _Safe_container()
63       {
64           if (__x._M_cont().get_allocator() == __a)
65             _Base::_M_swap(__x);
66           else
67             __x._M_invalidate_all();
68       }
69 
70     protected:
_Safe_container(_Safe_container && __x,const _Alloc & __a)71       _Safe_container(_Safe_container&& __x, const _Alloc& __a)
72       : _Safe_container(std::move(__x), __a,
73                           typename std::allocator_traits<_Alloc>::is_always_equal{})
74       { }
75 #endif
76 
77       // Copy assignment invalidate all iterators.
78       _Safe_container&
79       operator=(const _Safe_container&) _GLIBCXX_NOEXCEPT
80       {
81           this->_M_invalidate_all();
82           return *this;
83       }
84 
85 #if __cplusplus >= 201103L
86       _Safe_container&
87       operator=(_Safe_container&& __x) noexcept
88       {
89           if (std::__addressof(__x) == this)
90             {
91               // Standard containers have a valid but unspecified value after
92               // self-move, so we invalidate all debug iterators even if the
93               // underlying container happens to preserve its contents.
94               this->_M_invalidate_all();
95               return *this;
96             }
97 
98           if (_IsCxx11AllocatorAware)
99             {
100               typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
101 
102               bool __xfer_memory = _Alloc_traits::_S_propagate_on_move_assign()
103                 || _M_cont().get_allocator() == __x._M_cont().get_allocator();
104               if (__xfer_memory)
105                 _Base::_M_swap(__x);
106               else
107                 this->_M_invalidate_all();
108             }
109           else
110             _Base::_M_swap(__x);
111 
112           __x._M_invalidate_all();
113           return *this;
114       }
115 
116       void
_M_swap(_Safe_container & __x)117       _M_swap(_Safe_container& __x) noexcept
118       {
119           if (_IsCxx11AllocatorAware)
120             {
121               typedef __gnu_cxx::__alloc_traits<_Alloc> _Alloc_traits;
122 
123               if (!_Alloc_traits::_S_propagate_on_swap())
124                 __glibcxx_check_equal_allocs(this->_M_cont()._M_base(),
125                                                      __x._M_cont()._M_base());
126             }
127 
128           _Base::_M_swap(__x);
129       }
130 #endif
131     };
132 
133 } // namespace __gnu_debug
134 
135 #endif
136