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| ** |
| ** Copyright (C) 2016 The Qt Company Ltd. |
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| ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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| |
| |
| |
| #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 |