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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** 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 either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** 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 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qcachingiterator_p.h"
QT_BEGIN_NAMESPACE
using namespace QPatternist;
CachingIterator::CachingIterator(ItemSequenceCacheCell::Vector &cacheCells,
const VariableSlotID slot,
const DynamicContext::Ptr &context) : m_position(0),
m_varSlot(slot),
m_context(context),
m_cacheCells(cacheCells),
m_usingCache(true)
{
Q_ASSERT(m_varSlot > -1);
Q_ASSERT(m_context);
Q_ASSERT(m_cacheCells.at(m_varSlot).sourceIterator);
Q_ASSERT_X((m_cacheCells.at(m_varSlot).cachedItems.isEmpty() && m_cacheCells.at(m_varSlot).cacheState == ItemSequenceCacheCell::Empty) ||
m_cacheCells.at(m_varSlot).cacheState == ItemSequenceCacheCell::PartiallyPopulated,
Q_FUNC_INFO,
"It makes no sense to construct a CachingIterator for a cache that is ItemSequenceCacheCell::Full.");
}
Item CachingIterator::next()
{
ItemSequenceCacheCell &cell = m_cacheCells[m_varSlot];
if(m_position == -1)
return Item();
if(m_usingCache)
{
++m_position;
/* QAbstractXmlForwardIterator::position() starts at 1, while Qt's container classes
* starts at 0. */
if(m_position - 1 < cell.cachedItems.count())
{
m_current = cell.cachedItems.at(m_position - 1);
return m_current;
}
else
{
cell.cacheState = ItemSequenceCacheCell::PartiallyPopulated;
m_usingCache = false;
/* We decrement here so we don't have to add a branch for this
* when using the source QAbstractXmlForwardIterator below. */
--m_position;
}
}
m_current = cell.sourceIterator->next();
if(m_current)
{
cell.cachedItems.append(m_current);
Q_ASSERT(cell.cacheState == ItemSequenceCacheCell::PartiallyPopulated);
++m_position;
return m_current;
}
else
{
m_position = -1;
cell.cacheState = ItemSequenceCacheCell::Full;
return Item();
}
}
Item CachingIterator::current() const
{
return m_current;
}
xsInteger CachingIterator::position() const
{
return m_position;
}
Item::Iterator::Ptr CachingIterator::copy() const
{
const ItemSequenceCacheCell &cell = m_cacheCells.at(m_varSlot);
if(cell.cacheState == ItemSequenceCacheCell::Full)
return makeListIterator(cell.cachedItems);
else
return Item::Iterator::Ptr(new CachingIterator(m_cacheCells, m_varSlot, m_context));
}
QT_END_NAMESPACE
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