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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_GeneralComparison_H

#define Patternist_GeneralComparison_H

#include "qatomiccomparator_p.h"

#include "qpaircontainer_p.h"

#include "qcomparisonplatform_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Implements XPath 2.0's general comparions, such as the <tt>=</tt> operator.

     *

     * ComparisonPlatform is inherited with @c protected scope because ComparisonPlatform

     * must access members of GeneralComparison.

     *

     * @see <a href="http://www.w3.org/TR/xpath20/#id-general-comparisons">XML Path Language

     * (XPath) 2.0, 3.5.2 General Comparisons</a>

     * @author Frans Englich <frans.englich@nokia.com>

     * @ingroup Patternist_expressions

     */

    class GeneralComparison : public PairContainer,

                              public ComparisonPlatform<GeneralComparison,

                                                        true /* We want to report errors. */,

                                                        AtomicComparator::AsGeneralComparison>

    {

    public:

        GeneralComparison(const Expression::Ptr &op1,

                          const AtomicComparator::Operator op,

                          const Expression::Ptr &op2,

                          const bool isBackwardsCompat = false);

        virtual bool evaluateEBV(const DynamicContext::Ptr &) const;

        virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,

                                          const SequenceType::Ptr &reqType);

        virtual SequenceType::List expectedOperandTypes() const;

        virtual SequenceType::Ptr staticType() const;

        virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;

        /**

         * @returns always IDGeneralComparison

         */

        virtual ID id() const;

        virtual QList<QExplicitlySharedDataPointer<OptimizationPass> > optimizationPasses() const;

        /**

         * @returns the operator that this GeneralComparison is using.

         */

        inline AtomicComparator::Operator operatorID() const

        {

            return m_operator;

        }

        /**

         * Overridden to optimize case-insensitive compares.

         */

        virtual Expression::Ptr compress(const StaticContext::Ptr &context);

    private:

        static inline void updateType(ItemType::Ptr &type,

                                      const Expression::Ptr &source);

        AtomicComparator::Ptr fetchGeneralComparator(Expression::Ptr &op1,

                                                     Expression::Ptr &op2,

                                                     const ReportContext::Ptr &context) const;

        bool generalCompare(const Item &op1,

                            const Item &op2,

                            const DynamicContext::Ptr &context) const;

        const AtomicComparator::Operator m_operator;

        const bool m_isBackwardsCompat;

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif