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 "Node.h"
33 #include "XPathValue.h"
34 #include <wtf/HashMap.h>
35 #include <wtf/Vector.h>
36 #include <wtf/text/StringHash.h>
37 
38 namespace WebCore {
39 
40     namespace XPath {
41 
42         struct EvaluationContext {
43             WTF_MAKE_FAST_ALLOCATED;
44         public:
45             RefPtr<Node> node;
46             unsigned long size;
47             unsigned long position;
48             HashMap<String, String> variableBindings;
49 
50             bool hadTypeConversionError;
51         };
52 
53         class ParseNode {
54         public:
~ParseNode()55             virtual ~ParseNode() { }
56         };
57 
58         class Expression : public ParseNode {
59             WTF_MAKE_NONCOPYABLE(Expression); WTF_MAKE_FAST_ALLOCATED;
60         public:
61             static EvaluationContext& evaluationContext();
62 
63             Expression();
64             virtual ~Expression();
65 
66             virtual Value evaluate() const = 0;
67 
addSubExpression(Expression * expr)68             void addSubExpression(Expression* expr)
69             {
70                 m_subExpressions.append(expr);
71                 m_isContextNodeSensitive |= expr->m_isContextNodeSensitive;
72                 m_isContextPositionSensitive |= expr->m_isContextPositionSensitive;
73                 m_isContextSizeSensitive |= expr->m_isContextSizeSensitive;
74             }
75 
isContextNodeSensitive()76             bool isContextNodeSensitive() const { return m_isContextNodeSensitive; }
isContextPositionSensitive()77             bool isContextPositionSensitive() const { return m_isContextPositionSensitive; }
isContextSizeSensitive()78             bool isContextSizeSensitive() const { return m_isContextSizeSensitive; }
setIsContextNodeSensitive(bool value)79             void setIsContextNodeSensitive(bool value) { m_isContextNodeSensitive = value; }
setIsContextPositionSensitive(bool value)80             void setIsContextPositionSensitive(bool value) { m_isContextPositionSensitive = value; }
setIsContextSizeSensitive(bool value)81             void setIsContextSizeSensitive(bool value) { m_isContextSizeSensitive = value; }
82 
83             virtual Value::Type resultType() const = 0;
84 
85         protected:
subExprCount()86             unsigned subExprCount() const { return m_subExpressions.size(); }
subExpr(unsigned i)87             Expression* subExpr(unsigned i) { return m_subExpressions[i]; }
subExpr(unsigned i)88             const Expression* subExpr(unsigned i) const { return m_subExpressions[i]; }
89 
90         private:
91             Vector<Expression*> m_subExpressions;
92 
93             // Evaluation details that can be used for optimization.
94             bool m_isContextNodeSensitive;
95             bool m_isContextPositionSensitive;
96             bool m_isContextSizeSensitive;
97         };
98 
99     }
100 
101 }
102 
103 #endif // ENABLE(XPATH)
104 
105 #endif // EXPRESSION_H
106 
107