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
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      _SafeContainer&
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:
57      _Safe_container(_Safe_container&& __x, const _Alloc&, std::true_type)
58      : _Safe_container(std::move(__x))
59      { }
60
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:
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
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