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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 |
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43 |
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44 #include "qcachingiterator_p.h" |
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45 |
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46 QT_BEGIN_NAMESPACE |
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47 |
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48 using namespace QPatternist; |
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49 |
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50 CachingIterator::CachingIterator(ItemSequenceCacheCell::Vector &cacheCells, |
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51 const VariableSlotID slot, |
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52 const DynamicContext::Ptr &context) : m_position(0), |
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53 m_varSlot(slot), |
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54 m_context(context), |
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55 m_cacheCells(cacheCells), |
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56 m_usingCache(true) |
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57 { |
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58 Q_ASSERT(m_varSlot > -1); |
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59 Q_ASSERT(m_context); |
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60 Q_ASSERT(m_cacheCells.at(m_varSlot).sourceIterator); |
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61 Q_ASSERT_X((m_cacheCells.at(m_varSlot).cachedItems.isEmpty() && m_cacheCells.at(m_varSlot).cacheState == ItemSequenceCacheCell::Empty) || |
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62 m_cacheCells.at(m_varSlot).cacheState == ItemSequenceCacheCell::PartiallyPopulated, |
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63 Q_FUNC_INFO, |
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64 "It makes no sense to construct a CachingIterator for a cache that is ItemSequenceCacheCell::Full."); |
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65 } |
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66 |
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67 Item CachingIterator::next() |
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68 { |
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69 ItemSequenceCacheCell &cell = m_cacheCells[m_varSlot]; |
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70 if(m_position == -1) |
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71 return Item(); |
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72 |
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73 if(m_usingCache) |
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74 { |
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75 ++m_position; |
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76 |
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77 /* QAbstractXmlForwardIterator::position() starts at 1, while Qt's container classes |
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78 * starts at 0. */ |
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79 if(m_position - 1 < cell.cachedItems.count()) |
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80 { |
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81 m_current = cell.cachedItems.at(m_position - 1); |
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82 return m_current; |
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83 } |
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84 else |
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85 { |
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86 cell.cacheState = ItemSequenceCacheCell::PartiallyPopulated; |
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87 m_usingCache = false; |
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88 /* We decrement here so we don't have to add a branch for this |
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89 * when using the source QAbstractXmlForwardIterator below. */ |
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90 --m_position; |
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91 } |
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92 } |
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93 |
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94 m_current = cell.sourceIterator->next(); |
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95 |
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96 if(m_current) |
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97 { |
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98 cell.cachedItems.append(m_current); |
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99 Q_ASSERT(cell.cacheState == ItemSequenceCacheCell::PartiallyPopulated); |
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100 ++m_position; |
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101 return m_current; |
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102 } |
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103 else |
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104 { |
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105 m_position = -1; |
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106 cell.cacheState = ItemSequenceCacheCell::Full; |
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107 return Item(); |
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108 } |
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109 } |
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110 |
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111 Item CachingIterator::current() const |
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112 { |
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113 return m_current; |
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114 } |
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115 |
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116 xsInteger CachingIterator::position() const |
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117 { |
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118 return m_position; |
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119 } |
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120 |
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121 Item::Iterator::Ptr CachingIterator::copy() const |
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122 { |
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123 const ItemSequenceCacheCell &cell = m_cacheCells.at(m_varSlot); |
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124 if(cell.cacheState == ItemSequenceCacheCell::Full) |
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125 return makeListIterator(cell.cachedItems); |
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126 else |
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127 return Item::Iterator::Ptr(new CachingIterator(m_cacheCells, m_varSlot, m_context)); |
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128 } |
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129 |
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130 QT_END_NAMESPACE |