XPathStep.h revision ab9e7a118cf1ea2e3a93dce683b2ded3e7291ddb 
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
36namespace WebCore {
37
38    namespace XPath {
39
40        class Predicate;
41
42        class Step : public ParseNode {
43            WTF_MAKE_NONCOPYABLE(Step); WTF_MAKE_FAST_ALLOCATED;
44        public:
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& 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
89        private:
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
102        void optimizeStepPair(Step*, Step*, bool& dropSecondStep);
103    }
104
105}
106
107#endif // ENABLE(XPATH)
108
109#endif // XPathStep_h
110