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39
40//
41// W A R N I N G
42// -------------
43//
44// This file is not part of the Qt API. It exists purely as an
45// implementation detail. 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
55QT_BEGIN_NAMESPACE
56
57namespace 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
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
163 void Path::setLast()
164 {
165 m_isLast = true;
166 }
167}
168
169QT_END_NAMESPACE
170
171#endif
172

source code of qtxmlpatterns/src/xmlpatterns/expr/qpath_p.h