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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
#ifndef Patternist_CachingIterator_H
#define Patternist_CachingIterator_H
#include <QList>
#include <QVector>
#include "qdynamiccontext_p.h"
#include "qitem_p.h"
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
namespace QPatternist
{
/**
* @short An QAbstractXmlForwardIterator that gets its item from a cache unless its empty, in
* which case it continues to populate the cache as well as deliver on its
* own from a source QAbstractXmlForwardIterator.
*
* @author Frans Englich <frans.frans.englich@nokia.com>
* @ingroup Patternist_iterators
*/
class CachingIterator : public Item::Iterator
{
public:
/**
* We always use the same cache cell so why don't we use it directly,
* instead of passing the slot and ItemSequenceCacheCell::Vector to
* this class? Because the GenericDynamicContext might decide to resize
* the vector and that would invalidate the reference.
*
* We intentionally pass in a non-const reference here.
*/
CachingIterator(ItemSequenceCacheCell::Vector &cacheCells,
const VariableSlotID slot,
const DynamicContext::Ptr &context);
virtual Item next();
virtual Item current() const;
virtual xsInteger position() const;
virtual Item::Iterator::Ptr copy() const;
private:
Item m_current;
xsInteger m_position;
/**
* This variable cannot be called m_slot, because
* /usr/include/sys/sysmacros.h on hpuxi-acc defines it.
*/
const VariableSlotID m_varSlot;
/**
* We don't use the context. We only keep a reference such that it
* doesn't get deleted, and m_cacheCells starts to dangle.
*/
const DynamicContext::Ptr m_context;
/**
* We intentionally store a reference here such that we are able to
* modify the item.
*/
ItemSequenceCacheCell::Vector &m_cacheCells;
/**
* Whether this CachingIterator is delivering items from
* m_cacheCell.cacheItems or from m_cacheCell.sourceIterator.
*/
bool m_usingCache;
};
}
QT_END_NAMESPACE
QT_END_HEADER
#endif
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