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      1 /*
      2  * Copyright (C) 2005 Frerich Raabe <raabe (at) 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:
     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 
     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 
     76             bool isContextNodeSensitive() const { return m_isContextNodeSensitive; }
     77             bool isContextPositionSensitive() const { return m_isContextPositionSensitive; }
     78             bool isContextSizeSensitive() const { return m_isContextSizeSensitive; }
     79             void setIsContextNodeSensitive(bool value) { m_isContextNodeSensitive = value; }
     80             void setIsContextPositionSensitive(bool value) { m_isContextPositionSensitive = value; }
     81             void setIsContextSizeSensitive(bool value) { m_isContextSizeSensitive = value; }
     82 
     83             virtual Value::Type resultType() const = 0;
     84 
     85         protected:
     86             unsigned subExprCount() const { return m_subExpressions.size(); }
     87             Expression* subExpr(unsigned i) { return m_subExpressions[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