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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 "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 : FastAllocBase {
     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, public Noncopyable {
     57         public:
     58             static EvaluationContext& evaluationContext();
     59 
     60             Expression();
     61             virtual ~Expression();
     62 
     63             virtual Value evaluate() const = 0;
     64 
     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 
     73             bool isContextNodeSensitive() const { return m_isContextNodeSensitive; }
     74             bool isContextPositionSensitive() const { return m_isContextPositionSensitive; }
     75             bool isContextSizeSensitive() const { return m_isContextSizeSensitive; }
     76             void setIsContextNodeSensitive(bool value) { m_isContextNodeSensitive = value; }
     77             void setIsContextPositionSensitive(bool value) { m_isContextPositionSensitive = value; }
     78             void setIsContextSizeSensitive(bool value) { m_isContextSizeSensitive = value; }
     79 
     80             virtual Value::Type resultType() const = 0;
     81 
     82         protected:
     83             unsigned subExprCount() const { return m_subExpressions.size(); }
     84             Expression* subExpr(unsigned i) { return m_subExpressions[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