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These rights are described in The Qt Company LGPL Exception 28 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. 29 ** 30 ** GNU General Public License Usage 31 ** Alternatively, this file may be used under the terms of the GNU 32 ** General Public License version 3.0 as published by the Free Software 33 ** Foundation and appearing in the file LICENSE.GPL included in the 34 ** packaging of this file. Please review the following information to 35 ** ensure the GNU General Public License version 3.0 requirements will be 36 ** met: http://www.gnu.org/copyleft/gpl.html. 37 ** 38 ** $QT_END_LICENSE$ 39 ** 40 ****************************************************************************/ 41 42 // 43 // W A R N I N G 44 // ------------- 45 // 46 // This file is not part of the Qt API. It exists purely as an 47 // implementation detail. This header file may change from version to 48 // version without notice, or even be removed. 49 // 50 // We mean it. 51 52 #ifndef Patternist_Path_H 53 #define Patternist_Path_H 54 55 #include "qpaircontainer_p.h" 56 57 QT_BEGIN_HEADER 58 59 QT_BEGIN_NAMESPACE 60 61 namespace QPatternist 62 { 63 64 /** 65 * @short Implements the path expression, containing two steps, such as in <tt>html/body</tt>. 66 * 67 * @see <a href="http://www.w3.org/TR/xquery/#id-path-expressions">XQuery 1.0: An 68 * XML Query Language, 3.2 Path Expressions</a> 69 * @author Frans Englich <frans.englich@nokia.com> 70 * @ingroup Patternist_expressions 71 */ 72 class Path : public PairContainer 73 { 74 public: 75 enum Kind 76 { 77 /** 78 * This Path is a plain old path expression as found in XPath. 79 * Sorting is performed, and atomics are disallowed as left 80 * operand. 81 */ 82 RegularPath = 1, 83 84 /** 85 * This Path emulates an @c xsl:for-each instruction. This means no 86 * sorting of result, and atomics are allowed as left operand. 87 */ 88 XSLTForEach, 89 90 /** 91 * This Path performs the iteration in an @c xsl:apply-templates 92 * instruction. This means sorting, and atomics are disallowed 93 * as left operand. 94 */ 95 ForApplyTemplate 96 }; 97 98 Path(const Expression::Ptr &operand1, 99 const Expression::Ptr &operand2, 100 const Kind kind = RegularPath); 101 102 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const; 103 virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const; 104 virtual void evaluateToSequenceReceiver(const DynamicContext::Ptr &context) const; 105 inline Item::Iterator::Ptr mapToSequence(const Item &item, 106 const DynamicContext::Ptr &context) const; 107 108 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context, 109 const SequenceType::Ptr &reqType); 110 111 virtual SequenceType::List expectedOperandTypes() const; 112 113 /** 114 * @returns the static type of the last step where the cardinality is multiplied with 115 * the cardinality of the first step's cardinality. 116 */ 117 virtual SequenceType::Ptr staticType() const; 118 119 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; 120 121 virtual Properties properties() const; 122 123 virtual Expression::Ptr compress(const StaticContext::Ptr &context); 124 125 /** 126 * @returns the item type of the last step's static type. 127 */ 128 virtual ItemType::Ptr newFocusType() const; 129 130 virtual ID id() const; 131 132 inline void setLast(); 133 kind()134 inline Kind kind() const 135 { 136 return m_kind; 137 } 138 139 private: 140 typedef QExplicitlySharedDataPointer<const Path> ConstPtr; 141 142 /** 143 * One might think this block exists for preventing multiple 144 * NodeSortExpressions to be created. However, that is not an issue, 145 * since NodeSortExpression optimizes this away anyway. 146 * 147 * The real reason is to avoid infinite recursion. When our typeCheck() 148 * forwards on the type check to the just created 149 * NodeSortExpression, it in turn calls typeCheck() on its child, which 150 * is this Path. Rince and repeat. 151 * 152 * We only create node sorts when we're a regular path expression, and 153 * not when standing in as a generic map expression. */ 154 bool m_hasCreatedSorter; 155 156 /** 157 * Whether this path is the step. For instance, in <tt>a/b/c</tt>, the 158 * last path has @c c as the right operand. 159 */ 160 bool m_isLast; 161 162 bool m_checkXPTY0018; 163 const Kind m_kind; 164 }; 165 setLast()166 void Path::setLast() 167 { 168 m_isLast = true; 169 } 170 } 171 172 QT_END_NAMESPACE 173 174 QT_END_HEADER 175 176 #endif 177