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  **
  ** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
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  ** This file is part of the QtXmlPatterns module of the Qt Toolkit.
  **
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  //
  //  W A R N I N G
  //  -------------
  //
  // This file is not part of the Qt API.  It exists purely as an
  // implementation detail.  This header file may change from version to
  // version without notice, or even be removed.
  //
  // We mean it.
  
  #ifndef Patternist_CardinalityVerifier_H
  #define Patternist_CardinalityVerifier_H
  
  #include <private/qsinglecontainer_p.h>
  
  QT_BEGIN_NAMESPACE
  
  namespace QPatternist
  {
  
      /**
       * @short Verifies that the sequence an Expression evaluates to conforms to a Cardinality.
       *
       * @see <a href="http://www.w3.org/TR/xpath-functions/#cardinality-funcs">XQuery 1.0 and
       * XPath 2.0 Functions and Operators, 15.2 Functions That Test the Cardinality of Sequences</a>
       * @author Frans Englich <frans.englich@nokia.com>
       * @ingroup Patternist_expressions
       */
      class CardinalityVerifier : public SingleContainer
      {
      public:
          CardinalityVerifier(const Expression::Ptr &operand,
                              const Cardinality &card,
                              const ReportContext::ErrorCode code);
  
          virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
          virtual Item evaluateSingleton(const DynamicContext::Ptr &) const;
  
          virtual SequenceType::List expectedOperandTypes() const;
          virtual SequenceType::Ptr staticType() const;
  
          virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
  
          /**
           * If the static cardinality of the operand is within the required cardinality,
           * the operand is returned as is, since results will always be valid and hence
           * is not a CardinalityVerifier necessary.
           */
          virtual Expression::Ptr compress(const StaticContext::Ptr &context);
  
          /**
           * A utility function for determining whether the static type of an Expression matches
           * a cardinality. More specifically, this function performs the cardinality verification
           * part of the Function Conversion Rules.
           *
           * @todo Mention the rewrite and when exactly an error is issued via @p context
           */
          static Expression::Ptr
          verifyCardinality(const Expression::Ptr &operand,
                            const Cardinality &card,
                            const StaticContext::Ptr &context,
                            const ReportContext::ErrorCode code = ReportContext::XPTY0004);
  
          virtual const SourceLocationReflection *actualReflection() const;
  
          ID id() const;
      private:
          /**
           * Centralizes a message string in order to increase consistency and
           * reduce work for translators.
           */
          static inline QString wrongCardinality(const Cardinality &req,
                                                 const Cardinality &got = Cardinality::empty());
  
          const Cardinality m_reqCard;
          const bool m_allowsMany;
          const ReportContext::ErrorCode m_errorCode;
      };
  }
  
  QT_END_NAMESPACE
  
  #endif
  