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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 // W A R N I N G |
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44 // ------------- |
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45 // |
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46 // This file is not part of the Qt API. It exists purely as an |
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47 // implementation detail. This header file may change from version to |
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48 // version without notice, or even be removed. |
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49 // |
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50 // We mean it. |
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51 |
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52 #ifndef Patternist_GenericPredicate_H |
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53 #define Patternist_GenericPredicate_H |
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54 |
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55 #include "qpaircontainer_p.h" |
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56 |
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57 QT_BEGIN_HEADER |
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58 |
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59 QT_BEGIN_NAMESPACE |
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60 |
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61 namespace QPatternist |
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62 { |
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63 /** |
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64 * @short A predicate that can handle all kinds of predicates and |
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65 * is therefore not very efficient, but can cope with all the tricky scenarios. |
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66 * |
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67 * @see FirstItemPredicate |
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68 * @see TruthPredicate |
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69 * @author Frans Englich <frans.englich@nokia.com> |
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70 * @ingroup Patternist_expressions |
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71 */ |
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72 class GenericPredicate : public PairContainer |
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73 { |
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74 public: |
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75 |
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76 /** |
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77 * Creates a predicate expression that filters the items gained |
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78 * from evaluating @p sourceExpression through the filter @p predicateExpression. |
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79 * |
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80 * This function performs type analyzis on the passed expressions, and may |
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81 * return more specialized expressions depending on the analyzis. |
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82 * |
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83 * If @p predicateExpression is an invalid predicate, an error is issued |
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84 * via the @p context. |
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85 */ |
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86 static Expression::Ptr create(const Expression::Ptr &sourceExpression, |
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87 const Expression::Ptr &predicateExpression, |
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88 const StaticContext::Ptr &context, |
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89 const QSourceLocation &location); |
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90 |
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91 static Expression::Ptr createFirstItem(const Expression::Ptr &sourceExpression); |
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92 |
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93 /** |
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94 * Creates a source iterator which is passed to the ItemMappingIterator |
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95 * and the Focus. The ItemMappingIterator modifies it with |
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96 * its QAbstractXmlForwardIterator::next() calls, and since the Focus references the same QAbstractXmlForwardIterator, |
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97 * the focus is automatically moved. |
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98 */ |
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99 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const; |
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100 |
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101 /** |
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102 * Doesn't return the first item from calling evaluateSequence(), but does the mapping |
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103 * manually. This avoid allocating an ItemMappingIterator. |
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104 */ |
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105 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const; |
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106 |
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107 inline Item mapToItem(const Item &subject, |
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108 const DynamicContext::Ptr &) const; |
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109 |
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110 virtual SequenceType::List expectedOperandTypes() const; |
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111 virtual SequenceType::Ptr staticType() const; |
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112 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; |
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113 virtual ID id() const; |
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114 |
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115 /** |
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116 * @returns always CreatesFocusForLast. |
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117 */ |
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118 virtual Properties properties() const; |
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119 |
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120 virtual QString description() const; |
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121 |
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122 protected: |
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123 |
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124 /** |
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125 * Creates a GenericPredicate which filters the items from the @p sourceExpression |
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126 * through @p predicate. |
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127 * |
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128 * This constructor is protected. The proper way to create predicates is via the static |
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129 * create() function. |
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130 */ |
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131 GenericPredicate(const Expression::Ptr &sourceExpression, |
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132 const Expression::Ptr &predicate); |
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133 |
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134 /** |
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135 * @returns the ItemType of the first operand's staticType(). |
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136 */ |
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137 virtual ItemType::Ptr newFocusType() const; |
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138 |
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139 private: |
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140 typedef QExplicitlySharedDataPointer<const GenericPredicate> ConstPtr; |
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141 }; |
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142 } |
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143 |
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144 QT_END_NAMESPACE |
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145 |
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146 QT_END_HEADER |
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147 |
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148 #endif |