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// Safe sequence implementation  -*- C++ -*-

// Copyright (C) 2003, 2004, 2005, 2006, 2009, 2010

// Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 3, or (at your option)

// any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional

// permissions described in the GCC Runtime Library Exception, version

// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and

// a copy of the GCC Runtime Library Exception along with this program;

// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

// <http://www.gnu.org/licenses/>.

/** @file debug/safe_sequence.h

 *  This file is a GNU debug extension to the Standard C++ Library.

 */

#ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H

#define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1

#include <debug/debug.h>

#include <debug/macros.h>

#include <debug/functions.h>

#include <debug/safe_base.h>

namespace __gnu_debug

{

  template<typename _Iterator, typename _Sequence>

    class _Safe_iterator;

  /** A simple function object that returns true if the passed-in

   *  value is not equal to the stored value. It saves typing over

   *  using both bind1st and not_equal.

   */

  template<typename _Type>

    class _Not_equal_to

    {

      _Type __value;

    public:

      explicit _Not_equal_to(const _Type& __v) : __value(__v) { }

      bool

      operator()(const _Type& __x) const

      { return __value != __x; }

    };

  /** A function object that returns true when the given random access

      iterator is at least @c n steps away from the given iterator. */

  template<typename _Iterator>

    class _After_nth_from

    {

      typedef typename std::iterator_traits<_Iterator>::difference_type

      difference_type;

      _Iterator _M_base;

      difference_type _M_n;

    public:

      _After_nth_from(const difference_type& __n, const _Iterator& __base)

      : _M_base(__base), _M_n(__n) { }

      bool

      operator()(const _Iterator& __x) const

      { return __x - _M_base >= _M_n; }

    };

  /**

   * @brief Base class for constructing a @a safe sequence type that

   * tracks iterators that reference it.

   *

   * The class template %_Safe_sequence simplifies the construction of

   * @a safe sequences that track the iterators that reference the

   * sequence, so that the iterators are notified of changes in the

   * sequence that may affect their operation, e.g., if the container

   * invalidates its iterators or is destructed. This class template

   * may only be used by deriving from it and passing the name of the

   * derived class as its template parameter via the curiously

   * recurring template pattern. The derived class must have @c

   * iterator and @const_iterator types that are instantiations of

   * class template _Safe_iterator for this sequence. Iterators will

   * then be tracked automatically.

   */

  template<typename _Sequence>

    class _Safe_sequence : public _Safe_sequence_base

    {

    public:

      /** Invalidates all iterators @c x that reference this sequence,

          are not singular, and for which @c pred(x) returns @c

          true. The user of this routine should be careful not to make

          copies of the iterators passed to @p pred, as the copies may

          interfere with the invalidation. */

      template<typename _Predicate>

        void

        _M_invalidate_if(_Predicate __pred);

      /** Transfers all iterators that reference this memory location

          to this sequence from whatever sequence they are attached

          to. */

      template<typename _Iterator>

        void

        _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x);

    };

  template<typename _Sequence>

    template<typename _Predicate>

      void

      _Safe_sequence<_Sequence>::

      _M_invalidate_if(_Predicate __pred)

      {

        typedef typename _Sequence::iterator iterator;

        typedef typename _Sequence::const_iterator const_iterator;

        __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());

        for (_Safe_iterator_base* __iter = _M_iterators; __iter;)

          {

            iterator* __victim = static_cast<iterator*>(__iter);

            __iter = __iter->_M_next;

            if (!__victim->_M_singular())

              {

                if (__pred(__victim->base()))

                  __victim->_M_invalidate_single();

              }

          }

        for (_Safe_iterator_base* __iter2 = _M_const_iterators; __iter2;)

          {

            const_iterator* __victim = static_cast<const_iterator*>(__iter2);

            __iter2 = __iter2->_M_next;

            if (!__victim->_M_singular())

              {

                if (__pred(__victim->base()))

                  __victim->_M_invalidate_single();

              }

          }

      }

  template<typename _Sequence>

    template<typename _Iterator>

      void

      _Safe_sequence<_Sequence>::

      _M_transfer_iter(const _Safe_iterator<_Iterator, _Sequence>& __x)

      {

        _Safe_sequence_base* __from = __x._M_sequence;

        if (!__from)

          return;

        typedef typename _Sequence::iterator iterator;

        typedef typename _Sequence::const_iterator const_iterator;

        __gnu_cxx::__scoped_lock sentry(this->_M_get_mutex());

        for (_Safe_iterator_base* __iter = __from->_M_iterators; __iter;)

          {

            iterator* __victim = static_cast<iterator*>(__iter);

            __iter = __iter->_M_next;

            if (!__victim->_M_singular() && __victim->base() == __x.base())

              __victim->_M_attach_single(static_cast<_Sequence*>(this));

          }

        for (_Safe_iterator_base* __iter2 = __from->_M_const_iterators;

             __iter2;)

          {

            const_iterator* __victim = static_cast<const_iterator*>(__iter2);

            __iter2 = __iter2->_M_next;

            if (!__victim->_M_singular() && __victim->base() == __x.base())

              __victim->_M_attach_single(static_cast<_Sequence*>(this));

          }

      }

} // namespace __gnu_debug

#endif