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

   1 // Safe container/iterator base implementation  -*- C++ -*-
   2
   3 // Copyright (C) 2011-2015 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   public:
  80     /** Attaches this iterator to the given container, detaching it
  81      *  from whatever container it was attached to originally. If the
  82      *  new container is the NULL pointer, the iterator is left
  83      *  unattached.
  84      */
  85     void _M_attach(_Safe_sequence_base* __seq, bool __constant);
  86
  87     /** Likewise, but not thread-safe. */
  88     void _M_attach_single(_Safe_sequence_base* __seq, bool __constant) throw ();
  89
  90     /** Detach the iterator for whatever container it is attached to,
  91      *  if any.
  92     */
  93     void _M_detach();
  94
  95     /** Likewise, but not thread-safe. */
  96     void _M_detach_single() throw ();
  97   };
  98
  99   /**
 100    * @brief Base class that supports tracking of local iterators that
 101    * reference an unordered container.
 102    *
 103    * The %_Safe_unordered_container_base class provides basic support for
 104    * tracking iterators into an unordered container. Containers that track
 105    * iterators must derived from %_Safe_unordered_container_base publicly, so
 106    * that safe iterators (which inherit _Safe_iterator_base) can
 107    * attach to them. This class contains four linked lists of
 108    * iterators, one for constant iterators, one for mutable
 109    * iterators, one for constant local iterators, one for mutable local
 110    * iterators and a version number that allows very fast
 111    * invalidation of all iterators that reference the container.
 112    *
 113    * This class must ensure that no operation on it may throw an
 114    * exception, otherwise @a safe containers may fail to provide the
 115    * exception-safety guarantees required by the C++ standard.
 116    */
 117   class _Safe_unordered_container_base : public _Safe_sequence_base
 118   {
 119     typedef _Safe_sequence_base _Base;
 120   public:
 121     /// The list of mutable local iterators that reference this container
 122     _Safe_iterator_base* _M_local_iterators;
 123
 124     /// The list of constant local iterators that reference this container
 125     _Safe_iterator_base* _M_const_local_iterators;
 126
 127   protected:
 128     // Initialize with a version number of 1 and no iterators
 129     _Safe_unordered_container_base() noexcept
 130     : _M_local_iterators(nullptr), _M_const_local_iterators(nullptr)
 131     { }
 132
 133     // Copy constructor does not copy iterators.
 134     _Safe_unordered_container_base(const _Safe_unordered_container_base&)
 135     noexcept
 136     : _Safe_unordered_container_base() { }
 137
 138     // When moved unordered containers iterators are swapped.
 139     _Safe_unordered_container_base(_Safe_unordered_container_base&& __x)
 140     noexcept
 141     : _Safe_unordered_container_base()
 142     { this->_M_swap(__x); }
 143
 144     /** Notify all iterators that reference this container that the
 145         container is being destroyed. */
 146     ~_Safe_unordered_container_base() noexcept
 147     { this->_M_detach_all(); }
 148
 149     /** Detach all iterators, leaving them singular. */
 150     void
 151     _M_detach_all();
 152
 153     /** Swap this container with the given container. This operation
 154      *  also swaps ownership of the iterators, so that when the
 155      *  operation is complete all iterators that originally referenced
 156      *  one container now reference the other container.
 157      */
 158     void
 159     _M_swap(_Safe_unordered_container_base& __x) noexcept;
 160
 161   public:
 162     /** Attach an iterator to this container. */
 163     void
 164     _M_attach_local(_Safe_iterator_base* __it, bool __constant);
 165
 166     /** Likewise but not thread safe. */
 167     void
 168     _M_attach_local_single(_Safe_iterator_base* __it, bool __constant) throw ();
 169
 170     /** Detach an iterator from this container */
 171     void
 172     _M_detach_local(_Safe_iterator_base* __it);
 173
 174     /** Likewise but not thread safe. */
 175     void
 176     _M_detach_local_single(_Safe_iterator_base* __it) throw ();
 177   };
 178 } // namespace __gnu_debug
 179
 180 #endif