# safe_sequence.h

Go to the documentation of this file.

    00001 // Safe sequence implementation  -*- C++ -*-
    00002
    00003 // Copyright (C) 2003, 2004, 2005, 2006
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 2, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 /** @file debug/safe_sequence.h
    00032  *  This file is a GNU debug extension to the Standard C++ Library.
    00033  */
    00034
    00035 #ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
    00036 #define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
    00037
    00038 #include <debug/debug.h>
    00039 #include <debug/macros.h>
    00040 #include <debug/functions.h>
    00041 #include <debug/safe_base.h>
    00042
    00043 namespace __gnu_debug
    00044 {
    00045   template<typename _Iterator, typename _Sequence>
    00046     class _Safe_iterator;
    00047
    00048   /** A simple function object that returns true if the passed-in
    00049    *  value is not equal to the stored value. It saves typing over
    00050    *  using both bind1st and not_equal.
    00051    */
    00052   template<typename _Type>
    00053     class _Not_equal_to
    00054     {
    00055       _Type __value;
    00056
    00057     public:
    00058       explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
    00059
    00060       bool
    00061       operator()(const _Type& __x) const
    00062       { return __value != __x; }
    00063     };
    00064
    00065   /** A function object that returns true when the given random access
    00066       iterator is at least @c n steps away from the given iterator. */
    00067   template<typename _Iterator>
    00068     class _After_nth_from
    00069     {
    00070       typedef typename std::iterator_traits<_Iterator>::difference_type
    00071       difference_type;
    00072
    00073       _Iterator _M_base;
    00074       difference_type _M_n;
    00075
    00076     public:
    00077       _After_nth_from(const difference_type& __n, const _Iterator& __base)
    00078       : _M_base(__base), _M_n(__n) { }
    00079
    00080       bool
    00081       operator()(const _Iterator& __x) const
    00082       { return __x - _M_base >= _M_n; }
    00083     };
    00084
    00085   /**
    00086    * @brief Base class for constructing a "safe" sequence type that
    00087    * tracks iterators that reference it.
    00088    *
    00089    * The class template %_Safe_sequence simplifies the construction of
    00090    * "safe" sequences that track the iterators that reference the
    00091    * sequence, so that the iterators are notified of changes in the
    00092    * sequence that may affect their operation, e.g., if the container
    00093    * invalidates its iterators or is destructed. This class template
    00094    * may only be used by deriving from it and passing the name of the
    00095    * derived class as its template parameter via the curiously
    00096    * recurring template pattern. The derived class must have @c
    00097    * iterator and @const_iterator types that are instantiations of
    00098    * class template _Safe_iterator for this sequence. Iterators will
    00099    * then be tracked automatically.
    00100    */
    00101   template<typename _Sequence>
    00102     class _Safe_sequence : public _Safe_sequence_base
    00103     {
    00104     public:
    00105       /** Invalidates all iterators @c x that reference this sequence,
    00106       are not singular, and for which @c pred(x) returns @c
    00107       true. The user of this routine should be careful not to make
    00108       copies of the iterators passed to @p pred, as the copies may
    00109       interfere with the invalidation. */
    00110       template<typename _Predicate>
    00111         void
    00112         _M_invalidate_if(_Predicate __pred);
    00113
    00114       /** Transfers all iterators that reference this memory location
    00115       to this sequence from whatever sequence they are attached
    00116       to. */
    00117       template<typename _Iterator>
    00118         void
    00119         _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x);
    00120     };
    00121
    00122   template<typename _Sequence>
    00123     template<typename _Predicate>
    00124       void
    00125       _Safe_sequence<_Sequence>::
    00126       _M_invalidate_if(_Predicate __pred)
    00127       {
    00128         typedef typename _Sequence::iterator iterator;
    00129         typedef typename _Sequence::const_iterator const_iterator;
    00130
    00131     __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
    00132         for (_Safe_iterator_base* __iter = _M_iterators; __iter;)
    00133       {
    00134         iterator* __victim = static_cast<iterator*>(__iter);
    00135         __iter = __iter->_M_next;
    00136         if (!__victim->_M_singular())
    00137           {
    00138         if (__pred(__victim->base()))
    00139           __victim->_M_invalidate_single();
    00140           }
    00141       }
    00142
    00143         for (_Safe_iterator_base* __iter2 = _M_const_iterators; __iter2;)
    00144       {
    00145         const_iterator* __victim = static_cast<const_iterator*>(__iter2);
    00146         __iter2 = __iter2->_M_next;
    00147         if (!__victim->_M_singular())
    00148           {
    00149         if (__pred(__victim->base()))
    00150           __victim->_M_invalidate_single();
    00151           }
    00152       }
    00153       }
    00154
    00155   template<typename _Sequence>
    00156     template<typename _Iterator>
    00157       void
    00158       _Safe_sequence<_Sequence>::
    00159       _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x)
    00160       {
    00161     _Safe_sequence_base* __from = __x._M_sequence;
    00162     if (!__from)
    00163       return;
    00164
    00165         typedef typename _Sequence::iterator iterator;
    00166         typedef typename _Sequence::const_iterator const_iterator;
    00167
    00168     __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
    00169         for (_Safe_iterator_base* __iter = __from->_M_iterators; __iter;)
    00170       {
    00171         iterator* __victim = static_cast<iterator*>(__iter);
    00172         __iter = __iter->_M_next;
    00173         if (!__victim->_M_singular() && __victim->base() == __x.base())
    00174           __victim->_M_attach_single(static_cast<_Sequence*>(this));
    00175       }
    00176
    00177         for (_Safe_iterator_base* __iter2 = __from->_M_const_iterators;
    00178          __iter2;)
    00179       {
    00180         const_iterator* __victim = static_cast<const_iterator*>(__iter2);
    00181         __iter2 = __iter2->_M_next;
    00182         if (!__victim->_M_singular() && __victim->base() == __x.base())
    00183           __victim->_M_attach_single(static_cast<_Sequence*>(this));
    00184       }
    00185       }
    00186 } // namespace __gnu_debug
    00187
    00188 #endif