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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 #include "core/dom/Node.h"
     31 #include "core/xml/XPathValue.h"
     32 #include "wtf/HashMap.h"
     33 #include "wtf/Vector.h"
     34 #include "wtf/text/StringHash.h"
     35 
     36 namespace WebCore {
     37 
     38 namespace XPath {
     39 
     40 struct EvaluationContext {
     41     WTF_MAKE_FAST_ALLOCATED;
     42 public:
     43     RefPtrWillBePersistent<Node> node;
     44     unsigned long size;
     45     unsigned long position;
     46     HashMap<String, String> variableBindings;
     47 
     48     bool hadTypeConversionError;
     49 };
     50 
     51 class ParseNode : public NoBaseWillBeGarbageCollectedFinalized<ParseNode> {
     52 public:
     53     virtual ~ParseNode() { }
     54     virtual void trace(Visitor*) { }
     55 };
     56 
     57 class Expression : public ParseNode {
     58     WTF_MAKE_NONCOPYABLE(Expression); WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED;
     59 public:
     60     static EvaluationContext& evaluationContext();
     61 
     62     Expression();
     63     virtual ~Expression();
     64     virtual void trace(Visitor*) OVERRIDE;
     65 
     66     virtual Value evaluate() const = 0;
     67 
     68     void addSubExpression(PassOwnPtrWillBeRawPtr<Expression> expr)
     69     {
     70         m_isContextNodeSensitive |= expr->m_isContextNodeSensitive;
     71         m_isContextPositionSensitive |= expr->m_isContextPositionSensitive;
     72         m_isContextSizeSensitive |= expr->m_isContextSizeSensitive;
     73         m_subExpressions.append(expr);
     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].get(); }
     88     const Expression* subExpr(unsigned i) const { return m_subExpressions[i].get(); }
     89 
     90 private:
     91     WillBeHeapVector<OwnPtrWillBeMember<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 // XPathExpressionNode_h
    104