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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_AxisStep_H
51#define Patternist_AxisStep_H
52
53#include <private/qemptycontainer_p.h>
54#include <private/qitem_p.h>
55
56QT_BEGIN_NAMESPACE
57
58namespace QPatternist
59{
60 /**
61 * @short A step in a path expression that with an axis and a node test evaluates
62 * to a sequence of nodes from the context item.
63 *
64 * @author Frans Englich <frans.englich@nokia.com>
65 * @ingroup Patternist_expressions
66 */
67 class Q_AUTOTEST_EXPORT AxisStep : public EmptyContainer
68 {
69 public:
70 AxisStep(const QXmlNodeModelIndex::Axis axis,
71 const ItemType::Ptr &nodeTest);
72
73 virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &) const;
74 virtual Item evaluateSingleton(const DynamicContext::Ptr &) const;
75
76 /**
77 * Returns @p node if it matches the node test this step is using, otherwise @c null.
78 */
79 inline Item mapToItem(const QXmlNodeModelIndex &node,
80 const DynamicContext::Ptr &context) const;
81
82 virtual SequenceType::List expectedOperandTypes() const;
83 virtual SequenceType::Ptr staticType() const;
84
85 /**
86 * Rewrites to ParentNodeAxis, if possible.
87 */
88 virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
89 const SequenceType::Ptr &reqType);
90
91 /**
92 * @returns always BuiltinTypes::node;
93 */
94 virtual ItemType::Ptr expectedContextItemType() const;
95
96 virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
97
98 virtual Properties properties() const;
99
100 /**
101 * @returns the axis this step is using.
102 */
103 QXmlNodeModelIndex::Axis axis() const;
104
105 /**
106 * @returns the node test this step is using.
107 */
108 inline ItemType::Ptr nodeTest() const
109 {
110 return m_nodeTest;
111 }
112
113 void setNodeTest(const ItemType::Ptr &nev)
114 {
115 m_nodeTest = nev;
116 }
117
118 /**
119 * @short Prints the EBNF name corresponding to @p axis.
120 *
121 * For instance, for QXmlNodeModelIndex::Child, "child" is returned.
122 *
123 * Apart from being used in this class, it is used in the SDK.
124 */
125 static QString axisName(const QXmlNodeModelIndex::Axis axis);
126
127 virtual ID id() const;
128 virtual PatternPriority patternPriority() const;
129
130 inline void setAxis(const QXmlNodeModelIndex::Axis newAxis);
131
132 private:
133 typedef QExplicitlySharedDataPointer<const AxisStep> ConstPtr;
134
135 static const QXmlNodeModelIndex::NodeKind s_whenAxisNodeKindEmpty[];
136
137 /**
138 * @returns @c true when the axis @p axis and a node test testing node of
139 * type @p nodeKind always produces an empty sequence. One such example
140 * is <tt>attribute::comment()</tt>.
141 */
142 static bool isAlwaysEmpty(const QXmlNodeModelIndex::Axis axis,
143 const QXmlNodeModelIndex::NodeKind nodeKind);
144
145 /**
146 * The reason this variable is mutable, is that in the case of XSL-T patterns,
147 * we do quite some reordering.
148 */
149 QXmlNodeModelIndex::Axis m_axis;
150 ItemType::Ptr m_nodeTest;
151 };
152
153 void AxisStep::setAxis(const QXmlNodeModelIndex::Axis newAxis)
154 {
155 m_axis = newAxis;
156 }
157
158}
159
160QT_END_NAMESPACE
161
162#endif
163

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