diff -r 000000000000 -r 1918ee327afb src/xmlpatterns/iterators/qcachingiterator.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/iterators/qcachingiterator.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,130 @@
+/****************************************************************************
+**
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+
+#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