/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
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** use the contact form at http://qt.digia.com/contact-us.
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** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
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** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
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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_EmptySequenceType_H
#define Patternist_EmptySequenceType_H

#include "qatomictype_p.h"
#include "qsequencetype_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist
{

    /**
     * @short Represents the <tt>empty-sequence()</tt> type.
     *
     * @ingroup Patternist_types
     * @author Frans Englich <frans.englich@nokia.com>
     */
    class EmptySequenceType : public ItemType,
                              public SequenceType
    {
    public:
        typedef QExplicitlySharedDataPointer<EmptySequenceType> Ptr;

        /**
         * Possibly surprisingly, this function also returns true for the @c none type.
         *
         * @returns @c true if @p other is NoneType or EmptySequenceType, otherwise @c false.
         */
        virtual bool xdtTypeMatches(const ItemType::Ptr &other) const;

        /**
         * @returns always @c false
         */
        virtual bool itemMatches(const Item &item) const;

        /**
         * @returns always "empty-sequence()"
         */
        virtual QString displayName(const NamePool::Ptr &np) const;

        virtual ItemType::Ptr xdtSuperType() const;

        virtual bool isNodeType() const;
        virtual bool isAtomicType() const;

        /**
         * @return always Cardinality::empty()
         */
        virtual Cardinality cardinality() const;

        /**
         * @returns always 'this' since it is also an ItemType
         */
        virtual ItemType::Ptr itemType() const;

        /**
         * @returns always @c xs:anyAtomicType
         */
        virtual ItemType::Ptr atomizedType() const;

    protected:
        friend class CommonSequenceTypes;
        EmptySequenceType();
    };
}

QT_END_NAMESPACE

QT_END_HEADER

#endif