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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 XPathExpressionNode_h
28 #define XPathExpressionNode_h
29 
30 #if ENABLE(XPATH)
31 
32 #include "StringHash.h"
33 #include "Node.h"
34 #include "XPathValue.h"
35 #include <wtf/HashMap.h>
36 #include <wtf/Vector.h>
37 
38 namespace WebCore {
39 
40     namespace XPath {
41 
42         struct EvaluationContext {
43             RefPtr<Node> node;
44             unsigned long size;
45             unsigned long position;
46             HashMap<String, String> variableBindings;
47 
48             bool hadTypeConversionError;
49         };
50 
51         class ParseNode {
52         public:
~ParseNode()53             virtual ~ParseNode() { }
54         };
55 
56         class Expression : public ParseNode, public Noncopyable {
57         public:
58             static EvaluationContext& evaluationContext();
59 
60             Expression();
61             virtual ~Expression();
62 
63             virtual Value evaluate() const = 0;
64 
addSubExpression(Expression * expr)65             void addSubExpression(Expression* expr)
66             {
67                 m_subExpressions.append(expr);
68                 m_isContextNodeSensitive |= expr->m_isContextNodeSensitive;
69                 m_isContextPositionSensitive |= expr->m_isContextPositionSensitive;
70                 m_isContextSizeSensitive |= expr->m_isContextSizeSensitive;
71             }
72 
isContextNodeSensitive()73             bool isContextNodeSensitive() const { return m_isContextNodeSensitive; }
isContextPositionSensitive()74             bool isContextPositionSensitive() const { return m_isContextPositionSensitive; }
isContextSizeSensitive()75             bool isContextSizeSensitive() const { return m_isContextSizeSensitive; }
setIsContextNodeSensitive(bool value)76             void setIsContextNodeSensitive(bool value) { m_isContextNodeSensitive = value; }
setIsContextPositionSensitive(bool value)77             void setIsContextPositionSensitive(bool value) { m_isContextPositionSensitive = value; }
setIsContextSizeSensitive(bool value)78             void setIsContextSizeSensitive(bool value) { m_isContextSizeSensitive = value; }
79 
80             virtual Value::Type resultType() const = 0;
81 
82         protected:
subExprCount()83             unsigned subExprCount() const { return m_subExpressions.size(); }
subExpr(unsigned i)84             Expression* subExpr(unsigned i) { return m_subExpressions[i]; }
subExpr(unsigned i)85             const Expression* subExpr(unsigned i) const { return m_subExpressions[i]; }
86 
87         private:
88             Vector<Expression*> m_subExpressions;
89 
90             // Evaluation details that can be used for optimization.
91             bool m_isContextNodeSensitive;
92             bool m_isContextPositionSensitive;
93             bool m_isContextSizeSensitive;
94         };
95 
96     }
97 
98 }
99 
100 #endif // ENABLE(XPATH)
101 
102 #endif // EXPRESSION_H
103 
104