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 /*
  * expression.h - Copyright 2005 Frerich Raabe <raabe@kde.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #ifndef EXPRESSION_H
 #define EXPRESSION_H
 
 #include "util.h"
 
 #include <QHash>
 #include <QList>
 
 #include <dom/dom_string.h>
 #include <xml/dom_stringimpl.h>
 #include <xml/dom_nodelistimpl.h>
 #include <misc/shared.h>
 
 namespace DOM
 {
 class NodeImpl;
 }
 
 namespace khtml
 {
 
 class XPathNSResolverImpl;
 namespace XPath
 {
 
 struct EvaluationContext {
     EvaluationContext()
     {
         reset(nullptr, nullptr);
     }
 
     void reset(DOM::NodeImpl *ctx, XPathNSResolverImpl *res)
     {
         node     = ctx;
         resolver = res;
         size     = 1;
         position = 1;
         exceptionCode = 0;
     }
 
     DOM::NodeImpl *node;
     unsigned long size;
     unsigned long position;
     QHash<DOM::DOMString, DOM::DOMString> variableBindings;
 
     // reports only first one.
     void reportException(int ec)
     {
         if (!exceptionCode) {
             exceptionCode = ec;
         }
     }
 
     int exceptionCode;
 
     /* The function library is globally accessible through
      * FunctionLibrary::self()
      */
     XPathNSResolverImpl *resolver;
 };
 
 class Value
 {
 public:
     enum Type {
         Nodeset, Boolean, Number, String
     };
 
     Value();
     explicit Value(DOM::NodeImpl *value);
     explicit Value(const DomNodeList &value);
     explicit Value(bool value);
     explicit Value(double value);
     explicit Value(const DOM::DOMString &value);
 
     Type type() const;
     bool isNodeset() const;
     bool isBoolean() const;
     bool isNumber() const;
     bool isString() const;
 
     DomNodeList &toNodeset(); // may return 0
     const DomNodeList &toNodeset() const;
     bool toBoolean() const;
     double toNumber() const;
     DOM::DOMString toString() const;
 
     QString dump() const;
 
 private:
     // Catch undesired conversions -- this manages to go to bool otherwise!
     explicit Value(const char *);
 
     Type m_type;
     DomNodeList m_nodeset;
     bool m_bool;
     double m_number;
     DOM::DOMString m_string;
 };
 
 class Expression
 {
 public:
     static EvaluationContext &evaluationContext();
 
     Expression();
     virtual ~Expression();
     virtual Value evaluate() const;
 
     void addSubExpression(Expression *expr);
     void optimize();
     virtual bool isConstant() const;
 
     virtual QString dump() const = 0;
 
     static void reportInvalidExpressionErr();
     static void reportNamespaceErr();
 protected:
     unsigned int subExprCount() const;
     Expression *subExpr(unsigned int i);
     const Expression *subExpr(unsigned int i) const;
 
 private:
     virtual Value doEvaluate() const = 0;
 
     QList<Expression *> m_subExpressions;
     Value *m_constantValue;
 };
 
 } // namespace XPath
 
 } // namespace khtml
 
 #endif // EXPRESSION_H