/****************************************************************************
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** Copyright (C) 2011 Nokia Corporation 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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** GNU Lesser General Public License Usage
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** GNU General Public License Usage
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** Public License version 3.0 as published by the Free Software Foundation
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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_NodeSortExpression_H
#define Patternist_NodeSortExpression_H

#include "qsinglecontainer_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist
{
    /**
     * @short De-duplicates and sorts in document order the content that its
     * operand returns.
     *
     * @author Frans Englich <frans.englich@nokia.com>
     * @ingroup Patternist_expressions
     */
    class NodeSortExpression : public SingleContainer
    {
    public:
        NodeSortExpression(const Expression::Ptr &operand);

        virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
        virtual SequenceType::Ptr staticType() const;
        virtual SequenceType::List expectedOperandTypes() const;
        virtual Expression::Ptr compress(const StaticContext::Ptr &context);
        virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
        virtual Properties properties() const;

        /**
         * Ensures that result delivered from @p operand, is in document order.
         */
        static Expression::Ptr wrapAround(const Expression::Ptr &operand,
                                          const StaticContext::Ptr &context);

    private:
        static inline bool lessThanUsingNodeModel(const Item &n1,
                                                  const Item &n2);
    };
}

QT_END_NAMESPACE

QT_END_HEADER

#endif