source: trunk/src/xmlpatterns/iterators/qcachingiterator.cpp@ 219

Last change on this file since 219 was 2, checked in by Dmitry A. Kuminov, 16 years ago

Initially imported qt-all-opensource-src-4.5.1 from Trolltech.
File size: 4.7 KB
Line 
1/****************************************************************************
2**
3** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
4** Contact: Qt Software Information ([email protected])
5**
6** This file is part of the QtXmlPatterns module of the Qt Toolkit.
7**
8** $QT_BEGIN_LICENSE:LGPL$
9** Commercial Usage
10** Licensees holding valid Qt Commercial licenses may use this file in
11** accordance with the Qt Commercial License Agreement provided with the
12** Software or, alternatively, in accordance with the terms contained in
13** a written agreement between you and Nokia.
14**
15** GNU Lesser General Public License Usage
16** Alternatively, this file may be used under the terms of the GNU Lesser
17** General Public License version 2.1 as published by the Free Software
18** Foundation and appearing in the file LICENSE.LGPL included in the
19** packaging of this file. Please review the following information to
20** ensure the GNU Lesser General Public License version 2.1 requirements
21** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
22**
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24** additional rights. These rights are described in the Nokia Qt LGPL
25** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
26** package.
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28** GNU General Public License Usage
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30** General Public License version 3.0 as published by the Free Software
31** Foundation and appearing in the file LICENSE.GPL included in the
32** packaging of this file. Please review the following information to
33** ensure the GNU General Public License version 3.0 requirements will be
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40****************************************************************************/
41
42
43
44#include "qcachingiterator_p.h"
45
46QT_BEGIN_NAMESPACE
47
48using namespace QPatternist;
49
50CachingIterator::CachingIterator(ItemSequenceCacheCell::Vector &cacheCells,
51 const VariableSlotID slot,
52 const DynamicContext::Ptr &context) : m_position(0),
53 m_varSlot(slot),
54 m_context(context),
55 m_cacheCells(cacheCells),
56 m_usingCache(true)
57{
58 Q_ASSERT(m_varSlot > -1);
59 Q_ASSERT(m_context);
60 Q_ASSERT(m_cacheCells.at(m_varSlot).sourceIterator);
61 Q_ASSERT_X((m_cacheCells.at(m_varSlot).cachedItems.isEmpty() && m_cacheCells.at(m_varSlot).cacheState == ItemSequenceCacheCell::Empty) ||
62 m_cacheCells.at(m_varSlot).cacheState == ItemSequenceCacheCell::PartiallyPopulated,
63 Q_FUNC_INFO,
64 "It makes no sense to construct a CachingIterator for a cache that is ItemSequenceCacheCell::Full.");
65}
66
67Item CachingIterator::next()
68{
69 ItemSequenceCacheCell &cell = m_cacheCells[m_varSlot];
70 if(m_position == -1)
71 return Item();
72
73 if(m_usingCache)
74 {
75 ++m_position;
76
77 /* QAbstractXmlForwardIterator::position() starts at 1, while Qt's container classes
78 * starts at 0. */
79 if(m_position - 1 < cell.cachedItems.count())
80 {
81 m_current = cell.cachedItems.at(m_position - 1);
82 return m_current;
83 }
84 else
85 {
86 cell.cacheState = ItemSequenceCacheCell::PartiallyPopulated;
87 m_usingCache = false;
88 /* We decrement here so we don't have to add a branch for this
89 * when using the source QAbstractXmlForwardIterator below. */
90 --m_position;
91 }
92 }
93
94 m_current = cell.sourceIterator->next();
95
96 if(m_current)