safe_sequence.h

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00001 // Safe sequence implementation  -*- C++ -*-
00002 
00003 // Copyright (C) 2003, 2004, 2005, 2006, 2009
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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /** @file debug/safe_sequence.h
00027  *  This file is a GNU debug extension to the Standard C++ Library.
00028  */
00029 
00030 #ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
00031 #define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
00032 
00033 #include <debug/debug.h>
00034 #include <debug/macros.h>
00035 #include <debug/functions.h>
00036 #include <debug/safe_base.h>
00037 
00038 namespace __gnu_debug
00039 {
00040   template<typename _Iterator, typename _Sequence>
00041     class _Safe_iterator;
00042 
00043   /** A simple function object that returns true if the passed-in
00044    *  value is not equal to the stored value. It saves typing over
00045    *  using both bind1st and not_equal.
00046    */
00047   template<typename _Type>
00048     class _Not_equal_to
00049     {
00050       _Type __value;
00051 
00052     public:
00053       explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
00054 
00055       bool
00056       operator()(const _Type& __x) const
00057       { return __value != __x; }
00058     };
00059 
00060   /** A function object that returns true when the given random access
00061       iterator is at least @c n steps away from the given iterator. */
00062   template<typename _Iterator>
00063     class _After_nth_from
00064     {
00065       typedef typename std::iterator_traits<_Iterator>::difference_type
00066       difference_type;
00067 
00068       _Iterator _M_base;
00069       difference_type _M_n;
00070 
00071     public:
00072       _After_nth_from(const difference_type& __n, const _Iterator& __base)
00073       : _M_base(__base), _M_n(__n) { }
00074 
00075       bool
00076       operator()(const _Iterator& __x) const
00077       { return __x - _M_base >= _M_n; }
00078     };
00079 
00080   /**
00081    * @brief Base class for constructing a "safe" sequence type that
00082    * tracks iterators that reference it.
00083    *
00084    * The class template %_Safe_sequence simplifies the construction of
00085    * "safe" sequences that track the iterators that reference the
00086    * sequence, so that the iterators are notified of changes in the
00087    * sequence that may affect their operation, e.g., if the container
00088    * invalidates its iterators or is destructed. This class template
00089    * may only be used by deriving from it and passing the name of the
00090    * derived class as its template parameter via the curiously
00091    * recurring template pattern. The derived class must have @c
00092    * iterator and @const_iterator types that are instantiations of
00093    * class template _Safe_iterator for this sequence. Iterators will
00094    * then be tracked automatically.
00095    */
00096   template<typename _Sequence>
00097     class _Safe_sequence : public _Safe_sequence_base
00098     {
00099     public:
00100       /** Invalidates all iterators @c x that reference this sequence,
00101       are not singular, and for which @c pred(x) returns @c
00102       true. The user of this routine should be careful not to make
00103       copies of the iterators passed to @p pred, as the copies may
00104       interfere with the invalidation. */
00105       template<typename _Predicate>
00106         void
00107         _M_invalidate_if(_Predicate __pred);
00108 
00109       /** Transfers all iterators that reference this memory location
00110       to this sequence from whatever sequence they are attached
00111       to. */
00112       template<typename _Iterator>
00113         void
00114         _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x);
00115     };
00116 
00117   template<typename _Sequence>
00118     template<typename _Predicate>
00119       void
00120       _Safe_sequence<_Sequence>::
00121       _M_invalidate_if(_Predicate __pred)
00122       {
00123         typedef typename _Sequence::iterator iterator;
00124         typedef typename _Sequence::const_iterator const_iterator;
00125 
00126     __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
00127         for (_Safe_iterator_base* __iter = _M_iterators; __iter;)
00128       {
00129         iterator* __victim = static_cast<iterator*>(__iter);
00130         __iter = __iter->_M_next;
00131         if (!__victim->_M_singular())
00132           {
00133         if (__pred(__victim->base()))
00134           __victim->_M_invalidate_single();
00135           }
00136       }
00137 
00138         for (_Safe_iterator_base* __iter2 = _M_const_iterators; __iter2;)
00139       {
00140         const_iterator* __victim = static_cast<const_iterator*>(__iter2);
00141         __iter2 = __iter2->_M_next;
00142         if (!__victim->_M_singular())
00143           {
00144         if (__pred(__victim->base()))
00145           __victim->_M_invalidate_single();
00146           }
00147       }
00148       }
00149 
00150   template<typename _Sequence>
00151     template<typename _Iterator>
00152       void
00153       _Safe_sequence<_Sequence>::
00154       _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x)
00155       {
00156     _Safe_sequence_base* __from = __x._M_sequence;
00157     if (!__from)
00158       return;
00159 
00160         typedef typename _Sequence::iterator iterator;
00161         typedef typename _Sequence::const_iterator const_iterator;
00162 
00163     __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());
00164         for (_Safe_iterator_base* __iter = __from->_M_iterators; __iter;)
00165       {
00166         iterator* __victim = static_cast<iterator*>(__iter);
00167         __iter = __iter->_M_next;
00168         if (!__victim->_M_singular() && __victim->base() == __x.base())
00169           __victim->_M_attach_single(static_cast<_Sequence*>(this));
00170       }
00171 
00172         for (_Safe_iterator_base* __iter2 = __from->_M_const_iterators; 
00173          __iter2;)
00174       {
00175         const_iterator* __victim = static_cast<const_iterator*>(__iter2);
00176         __iter2 = __iter2->_M_next;
00177         if (!__victim->_M_singular() && __victim->base() == __x.base())
00178           __victim->_M_attach_single(static_cast<_Sequence*>(this));
00179       }
00180       }
00181 } // namespace __gnu_debug
00182 
00183 #endif

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