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

   1 // Safe sequence implementation  -*- C++ -*-
   2
   3 // Copyright (C) 2003-2020 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_sequence.h
  26  *  This file is a GNU debug extension to the Standard C++ Library.
  27  */
  28
  29 #ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
  30 #define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
  31
  32 #include <debug/assertions.h>
  33 #include <debug/macros.h>
  34 #include <debug/functions.h>
  35 #include <debug/safe_base.h>
  36
  37 namespace __gnu_debug
  38 {
  39   /** A simple function object that returns true if the passed-in
  40    *  value is not equal to the stored value. It saves typing over
  41    *  using both bind1st and not_equal.
  42    */
  43   template<typename _Type>
  44     class _Not_equal_to
  45     {
  46       _Type __value;
  47
  48     public:
  49       explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
  50
  51       bool
  52       operator()(const _Type& __x) const
  53       { return __value != __x; }
  54     };
  55
  56   /** A simple function object that returns true if the passed-in
  57    *  value is equal to the stored value. */
  58   template <typename _Type>
  59     class _Equal_to
  60     {
  61       _Type __value;
  62
  63     public:
  64       explicit _Equal_to(const _Type& __v) : __value(__v) { }
  65
  66       bool
  67       operator()(const _Type& __x) const
  68       { return __value == __x; }
  69     };
  70
  71   /** A function object that returns true when the given random access
  72       iterator is at least @c n steps away from the given iterator. */
  73   template<typename _Iterator>
  74     class _After_nth_from
  75     {
  76       typedef typename std::iterator_traits<_Iterator>::difference_type
  77       difference_type;
  78
  79       _Iterator _M_base;
  80       difference_type _M_n;
  81
  82     public:
  83       _After_nth_from(const difference_type& __n, const _Iterator& __base)
  84       : _M_base(__base), _M_n(__n) { }
  85
  86       bool
  87       operator()(const _Iterator& __x) const
  88       { return __x - _M_base >= _M_n; }
  89     };
  90
  91   /**
  92    * @brief Base class for constructing a @a safe sequence type that
  93    * tracks iterators that reference it.
  94    *
  95    * The class template %_Safe_sequence simplifies the construction of
  96    * @a safe sequences that track the iterators that reference the
  97    * sequence, so that the iterators are notified of changes in the
  98    * sequence that may affect their operation, e.g., if the container
  99    * invalidates its iterators or is destructed. This class template
 100    * may only be used by deriving from it and passing the name of the
 101    * derived class as its template parameter via the curiously
 102    * recurring template pattern. The derived class must have @c
 103    * iterator and @c const_iterator types that are instantiations of
 104    * class template _Safe_iterator for this sequence. Iterators will
 105    * then be tracked automatically.
 106    */
 107   template<typename _Sequence>
 108     class _Safe_sequence : public _Safe_sequence_base
 109     {
 110     public:
 111       /** Invalidates all iterators @c x that reference this sequence,
 112           are not singular, and for which @c __pred(x) returns @c
 113           true. @c __pred will be invoked with the normal iterators nested
 114           in the safe ones. */
 115       template<typename _Predicate>
 116         void
 117         _M_invalidate_if(_Predicate __pred);
 118
 119       /** Transfers all iterators @c x that reference @c from sequence,
 120           are not singular, and for which @c __pred(x) returns @c
 121           true. @c __pred will be invoked with the normal iterators nested
 122           in the safe ones. */
 123       template<typename _Predicate>
 124         void
 125         _M_transfer_from_if(_Safe_sequence& __from, _Predicate __pred);
 126     };
 127
 128   /// Like _Safe_sequence but with a special _M_invalidate_all implementation
 129   /// not invalidating past-the-end iterators. Used by node based sequence.
 130   template<typename _Sequence>
 131     class _Safe_node_sequence
 132     : public _Safe_sequence<_Sequence>
 133     {
 134     protected:
 135       void
 136       _M_invalidate_all()
 137       {
 138         typedef typename _Sequence::const_iterator _Const_iterator;
 139         typedef typename _Const_iterator::iterator_type _Base_const_iterator;
 140         typedef __gnu_debug::_Not_equal_to<_Base_const_iterator> _Not_equal;
 141         const _Sequence& __seq = *static_cast<_Sequence*>(this);
 142         this->_M_invalidate_if(_Not_equal(__seq._M_base().end()));
 143       }
 144     };
 145
 146 } // namespace __gnu_debug
 147
 148 #include <debug/safe_sequence.tcc>
 149
 150 #endif