contrib/gcc-8.0/libstdc++-v3/include/debug/safe_unordered_base.h

   1 // Safe container/iterator base implementation  -*- C++ -*-
   2
   3 // Copyright (C) 2011-2018 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_unordered_base.h
  26  *  This file is a GNU debug extension to the Standard C++ Library.
  27  */
  28
  29 #ifndef _GLIBCXX_DEBUG_SAFE_UNORDERED_BASE_H
  30 #define _GLIBCXX_DEBUG_SAFE_UNORDERED_BASE_H 1
  31
  32 #include <debug/safe_base.h>
  33
  34 namespace __gnu_debug
  35 {
  36   class _Safe_unordered_container_base;
  37
  38   /** \brief Basic functionality for a @a safe iterator.
  39    *
  40    *  The %_Safe_local_iterator_base base class implements the functionality
  41    *  of a safe local iterator that is not specific to a particular iterator
  42    *  type. It contains a pointer back to the container it references
  43    *  along with iterator version information and pointers to form a
  44    *  doubly-linked list of local iterators referenced by the container.
  45    *
  46    *  This class must not perform any operations that can throw an
  47    *  exception, or the exception guarantees of derived iterators will
  48    *  be broken.
  49    */
  50   class _Safe_local_iterator_base : public _Safe_iterator_base
  51   {
  52   protected:
  53     /** Initializes the iterator and makes it singular. */
  54     _Safe_local_iterator_base()
  55     { }
  56
  57     /** Initialize the iterator to reference the container pointed to
  58      *  by @p __seq. @p __constant is true when we are initializing a
  59      *  constant local iterator, and false if it is a mutable local iterator.
  60      *  Note that @p __seq may be NULL, in which case the iterator will be
  61      *  singular. Otherwise, the iterator will reference @p __seq and
  62      *  be nonsingular.
  63      */
  64     _Safe_local_iterator_base(const _Safe_sequence_base* __seq, bool __constant)
  65     { this->_M_attach(const_cast<_Safe_sequence_base*>(__seq), __constant); }
  66
  67     /** Initializes the iterator to reference the same container that
  68         @p __x does. @p __constant is true if this is a constant
  69         iterator, and false if it is mutable. */
  70     _Safe_local_iterator_base(const _Safe_local_iterator_base& __x,
  71                               bool __constant)
  72     { this->_M_attach(__x._M_sequence, __constant); }
  73
  74     ~_Safe_local_iterator_base() { this->_M_detach(); }
  75
  76     _Safe_unordered_container_base*
  77     _M_get_container() const noexcept;
  78
  79     /** Attaches this iterator to the given container, detaching it
  80      *  from whatever container it was attached to originally. If the
  81      *  new container is the NULL pointer, the iterator is left
  82      *  unattached.
  83      */
  84     void
  85     _M_attach(_Safe_sequence_base* __seq, bool __constant);
  86
  87     /** Likewise, but not thread-safe. */
  88     void
  89     _M_attach_single(_Safe_sequence_base* __seq, bool __constant) throw ();
  90
  91     /** Detach the iterator for whatever container it is attached to,
  92      *  if any.
  93     */
  94     void
  95     _M_detach();
  96
  97     /** Likewise, but not thread-safe. */
  98     void
  99     _M_detach_single() throw ();
 100   };
 101
 102   /**
 103    * @brief Base class that supports tracking of local iterators that
 104    * reference an unordered container.
 105    *
 106    * The %_Safe_unordered_container_base class provides basic support for
 107    * tracking iterators into an unordered container. Containers that track
 108    * iterators must derived from %_Safe_unordered_container_base publicly, so
 109    * that safe iterators (which inherit _Safe_iterator_base) can
 110    * attach to them. This class contains four linked lists of
 111    * iterators, one for constant iterators, one for mutable
 112    * iterators, one for constant local iterators, one for mutable local
 113    * iterators and a version number that allows very fast
 114    * invalidation of all iterators that reference the container.
 115    *
 116    * This class must ensure that no operation on it may throw an
 117    * exception, otherwise @a safe containers may fail to provide the
 118    * exception-safety guarantees required by the C++ standard.
 119    */
 120   class _Safe_unordered_container_base : public _Safe_sequence_base
 121   {
 122     friend class _Safe_local_iterator_base;
 123     typedef _Safe_sequence_base _Base;
 124
 125   public:
 126     /// The list of mutable local iterators that reference this container
 127     _Safe_iterator_base* _M_local_iterators;
 128
 129     /// The list of constant local iterators that reference this container
 130     _Safe_iterator_base* _M_const_local_iterators;
 131
 132   protected:
 133     // Initialize with a version number of 1 and no iterators
 134     _Safe_unordered_container_base() noexcept
 135     : _M_local_iterators(nullptr), _M_const_local_iterators(nullptr)
 136     { }
 137
 138     // Copy constructor does not copy iterators.
 139     _Safe_unordered_container_base(const _Safe_unordered_container_base&)
 140     noexcept
 141     : _Safe_unordered_container_base() { }
 142
 143     // When moved unordered containers iterators are swapped.
 144     _Safe_unordered_container_base(_Safe_unordered_container_base&& __x)
 145     noexcept
 146     : _Safe_unordered_container_base()
 147     { this->_M_swap(__x); }
 148
 149     /** Notify all iterators that reference this container that the
 150         container is being destroyed. */
 151     ~_Safe_unordered_container_base() noexcept
 152     { this->_M_detach_all(); }
 153
 154     /** Detach all iterators, leaving them singular. */
 155     void
 156     _M_detach_all();
 157
 158     /** Swap this container with the given container. This operation
 159      *  also swaps ownership of the iterators, so that when the
 160      *  operation is complete all iterators that originally referenced
 161      *  one container now reference the other container.
 162      */
 163     void
 164     _M_swap(_Safe_unordered_container_base& __x) noexcept;
 165
 166   private:
 167     /** Attach an iterator to this container. */
 168     void
 169     _M_attach_local(_Safe_iterator_base* __it, bool __constant);
 170
 171     /** Likewise but not thread safe. */
 172     void
 173     _M_attach_local_single(_Safe_iterator_base* __it, bool __constant) throw ();
 174
 175     /** Detach an iterator from this container */
 176     void
 177     _M_detach_local(_Safe_iterator_base* __it);
 178
 179     /** Likewise but not thread safe. */
 180     void
 181     _M_detach_local_single(_Safe_iterator_base* __it) throw ();
 182   };
 183 } // namespace __gnu_debug
 184
 185 #endif