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1 /*
2  * Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
3  * Copyright (C) 2006, 2009 Apple Inc.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #ifndef XPathStep_h
28 #define XPathStep_h
29 
30 #if ENABLE(XPATH)
31 
32 #include "Node.h"
33 #include "XPathExpressionNode.h"
34 #include "XPathNodeSet.h"
35 
36 namespace WebCore {
37 
38     namespace XPath {
39 
40         class Predicate;
41 
42         class Step : public ParseNode, public Noncopyable {
43         public:
44             enum Axis {
45                 AncestorAxis, AncestorOrSelfAxis, AttributeAxis,
46                 ChildAxis, DescendantAxis, DescendantOrSelfAxis,
47                 FollowingAxis, FollowingSiblingAxis, NamespaceAxis,
48                 ParentAxis, PrecedingAxis, PrecedingSiblingAxis,
49                 SelfAxis
50             };
51 
52             class NodeTest {
53             public:
54                 enum Kind {
55                     TextNodeTest, CommentNodeTest, ProcessingInstructionNodeTest, AnyNodeTest, NameTest
56                 };
57 
NodeTest(Kind kind)58                 NodeTest(Kind kind) : m_kind(kind) {}
NodeTest(Kind kind,const String & data)59                 NodeTest(Kind kind, const String& data) : m_kind(kind), m_data(data) {}
NodeTest(Kind kind,const String & data,const String & namespaceURI)60                 NodeTest(Kind kind, const String& data, const String& namespaceURI) : m_kind(kind), m_data(data), m_namespaceURI(namespaceURI) {}
61 
kind()62                 Kind kind() const { return m_kind; }
data()63                 const AtomicString& data() const { return m_data; }
namespaceURI()64                 const AtomicString& namespaceURI() const { return m_namespaceURI; }
mergedPredicates()65                 Vector<Predicate*>& mergedPredicates() { return m_mergedPredicates; }
mergedPredicates()66                 const Vector<Predicate*>& mergedPredicates() const { return m_mergedPredicates; }
67 
68             private:
69                 Kind m_kind;
70                 AtomicString m_data;
71                 AtomicString m_namespaceURI;
72 
73                 // When possible, we merge some or all predicates with node test for better performance.
74                 Vector<Predicate*> m_mergedPredicates;
75             };
76 
77             Step(Axis, const NodeTest& nodeTest, const Vector<Predicate*>& predicates = Vector<Predicate*>());
78             ~Step();
79 
80             void optimize();
81 
82             void evaluate(Node* context, NodeSet&) const;
83 
axis()84             Axis axis() const { return m_axis; }
nodeTest()85             const NodeTest& nodeTest() const { return m_nodeTest; }
86 
87         private:
88             friend void optimizeStepPair(Step*, Step*, bool&);
89             bool predicatesAreContextListInsensitive() const;
90 
91             void parseNodeTest(const String&);
92             void nodesInAxis(Node* context, NodeSet&) const;
93             String namespaceFromNodetest(const String& nodeTest) const;
94 
95             Axis m_axis;
96             NodeTest m_nodeTest;
97             Vector<Predicate*> m_predicates;
98         };
99 
100         void optimizeStepPair(Step*, Step*, bool& dropSecondStep);
101     }
102 
103 }
104 
105 #endif // ENABLE(XPATH)
106 
107 #endif // XPathStep_h
108