libstdc++-v3/include/debug/safe_container.h

   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&
  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