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#include "XPathExpressionNode.h"
31#include "XPathNodeSet.h"
32
33namespace WebCore {
34
35class Node;
36
37namespace XPath {
38
39class Predicate;
40
41class Step : public ParseNode {
42    WTF_MAKE_NONCOPYABLE(Step);
43    WTF_MAKE_FAST_ALLOCATED;
44public:
45    enum Axis {
46        AncestorAxis, AncestorOrSelfAxis, AttributeAxis,
47        ChildAxis, DescendantAxis, DescendantOrSelfAxis,
48        FollowingAxis, FollowingSiblingAxis, NamespaceAxis,
49        ParentAxis, PrecedingAxis, PrecedingSiblingAxis,
50        SelfAxis
51    };
52
53    class NodeTest {
54        WTF_MAKE_FAST_ALLOCATED;
55    public:
56        enum Kind {
57            TextNodeTest, CommentNodeTest, ProcessingInstructionNodeTest, AnyNodeTest, NameTest
58        };
59
60        NodeTest(Kind kind) : m_kind(kind) { }
61        NodeTest(Kind kind, const String& data) : m_kind(kind), m_data(data) { }
62        NodeTest(Kind kind, const String& data, const String& namespaceURI) : m_kind(kind), m_data(data), m_namespaceURI(namespaceURI) { }
63
64        Kind kind() const { return m_kind; }
65        const AtomicString& data() const { return m_data; }
66        const AtomicString& namespaceURI() const { return m_namespaceURI; }
67        Vector<Predicate*>& mergedPredicates() { return m_mergedPredicates; }
68        const Vector<Predicate*>& mergedPredicates() const { return m_mergedPredicates; }
69
70    private:
71        Kind m_kind;
72        AtomicString m_data;
73        AtomicString m_namespaceURI;
74
75        // When possible, we merge some or all predicates with node test for better performance.
76        Vector<Predicate*> m_mergedPredicates;
77    };
78
79    Step(Axis, const NodeTest&, const Vector<Predicate*>& predicates = Vector<Predicate*>());
80    ~Step();
81
82    void optimize();
83
84    void evaluate(Node* context, NodeSet&) const;
85
86    Axis axis() const { return m_axis; }
87    const NodeTest& nodeTest() const { return m_nodeTest; }
88
89private:
90    friend void optimizeStepPair(Step*, Step*, bool&);
91    bool predicatesAreContextListInsensitive() const;
92
93    void parseNodeTest(const String&);
94    void nodesInAxis(Node* context, NodeSet&) const;
95    String namespaceFromNodetest(const String& nodeTest) const;
96
97    Axis m_axis;
98    NodeTest m_nodeTest;
99    Vector<Predicate*> m_predicates;
100};
101
102void optimizeStepPair(Step*, Step*, bool& dropSecondStep);
103
104} // namespace XPath
105
106} // namespace WebCore
107
108#endif // XPathStep_h
109