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