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This header file may change from version to 46 // version without notice, or even be removed. 47 // 48 // We mean it. 49 50 #ifndef Patternist_Path_H 51 #define Patternist_Path_H 52 53 #include <private/qpaircontainer_p.h> 54 55 QT_BEGIN_NAMESPACE 56 57 namespace QPatternist 58 { 59 60 /** 61 * @short Implements the path expression, containing two steps, such as in <tt>html/body</tt>. 62 * 63 * @see <a href="http://www.w3.org/TR/xquery/#id-path-expressions">XQuery 1.0: An 64 * XML Query Language, 3.2 Path Expressions</a> 65 * @author Frans Englich <frans.englich@nokia.com> 66 * @ingroup Patternist_expressions 67 */ 68 class Q_AUTOTEST_EXPORT Path : public PairContainer 69 { 70 public: 71 enum Kind 72 { 73 /** 74 * This Path is a plain old path expression as found in XPath. 75 * Sorting is performed, and atomics are disallowed as left 76 * operand. 77 */ 78 RegularPath = 1, 79 80 /** 81 * This Path emulates an @c xsl:for-each instruction. This means no 82 * sorting of result, and atomics are allowed as left operand. 83 */ 84 XSLTForEach, 85 86 /** 87 * This Path performs the iteration in an @c xsl:apply-templates 88 * instruction. This means sorting, and atomics are disallowed 89 * as left operand. 90 */ 91 ForApplyTemplate 92 }; 93 94 Path(const Expression::Ptr &operand1, 95 const Expression::Ptr &operand2, 96 const Kind kind = RegularPath); 97 ~Path(); 98 99 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const; 100 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const; 101 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const; 102 inline Item::Iterator::Ptr mapToSequence(const Item &item, 103 const DynamicContext::Ptr &context) const; 104 105 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context, 106 const SequenceType::Ptr &reqType); 107 108 virtual SequenceType::List expectedOperandTypes() const; 109 110 /** 111 * @returns the static type of the last step where the cardinality is multiplied with 112 * the cardinality of the first step's cardinality. 113 */ 114 virtual SequenceType::Ptr staticType() const; 115 116 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; 117 118 virtual Properties properties() const; 119 120 virtual Expression::Ptr compress(const StaticContext::Ptr &context); 121 122 /** 123 * @returns the item type of the last step's static type. 124 */ 125 virtual ItemType::Ptr newFocusType() const; 126 127 virtual ID id() const; 128 129 inline void setLast(); 130 kind()131 inline Kind kind() const 132 { 133 return m_kind; 134 } 135 136 private: 137 typedef QExplicitlySharedDataPointer<const Path> ConstPtr; 138 139 /** 140 * One might think this block exists for preventing multiple 141 * NodeSortExpressions to be created. However, that is not an issue, 142 * since NodeSortExpression optimizes this away anyway. 143 * 144 * The real reason is to avoid infinite recursion. When our typeCheck() 145 * forwards on the type check to the just created 146 * NodeSortExpression, it in turn calls typeCheck() on its child, which 147 * is this Path. Rince and repeat. 148 * 149 * We only create node sorts when we're a regular path expression, and 150 * not when standing in as a generic map expression. */ 151 bool m_hasCreatedSorter; 152 153 /** 154 * Whether this path is the step. For instance, in <tt>a/b/c</tt>, the 155 * last path has @c c as the right operand. 156 */ 157 bool m_isLast; 158 159 bool m_checkXPTY0018; 160 const Kind m_kind; 161 }; 162 setLast()163 void Path::setLast() 164 { 165 m_isLast = true; 166 } 167 } 168 169 QT_END_NAMESPACE 170 171 #endif 172