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Diffstat (limited to 'src/xmlpatterns/iterators/qcachingiterator.cpp')
-rw-r--r-- | src/xmlpatterns/iterators/qcachingiterator.cpp | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/src/xmlpatterns/iterators/qcachingiterator.cpp b/src/xmlpatterns/iterators/qcachingiterator.cpp new file mode 100644 index 0000000..1c0487d --- /dev/null +++ b/src/xmlpatterns/iterators/qcachingiterator.cpp @@ -0,0 +1,130 @@ +/**************************************************************************** +** +** Copyright (C) 2011 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 |