/****************************************************************************

**

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**

** This file is part of the QtXmlPatterns module of the Qt Toolkit.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** 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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**

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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_ProjectedExpression_H

#define Patternist_ProjectedExpression_H

#include "qitem_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    class ProjectedExpression

    {

    public:

        typedef ProjectedExpression * Ptr;

        typedef QVector<ProjectedExpression::Ptr> Vector;

        virtual ~ProjectedExpression()

        {

        }

        enum Action

        {

            Move = 0,

            Skip = 1,

            Keep = 2,

            KeepSubtree = 4 | Keep

        };

        virtual Action actionForElement(const QXmlName name,

                                        ProjectedExpression::Ptr &next) const

        {

            Q_UNUSED(name);

            Q_UNUSED(next);

            return Skip;

        }

    };

    class ProjectedNodeTest

    {

    public:

        typedef ProjectedNodeTest * Ptr;

        virtual ~ProjectedNodeTest()

        {

        }

        virtual bool isMatch(const QXmlNodeModelIndex::NodeKind kind) const

        {

            Q_UNUSED(kind);

            return false;

        }

    };

    class ProjectedStep : public ProjectedExpression

    {

    public:

        ProjectedStep(const ProjectedNodeTest::Ptr test,

                      const QXmlNodeModelIndex::Axis axis) : m_test(test),

                                               m_axis(axis)

        {

            Q_ASSERT(m_test);

        }

        virtual Action actionForElement(const QXmlName name,

                                        ProjectedExpression::Ptr &next) const

        {

            Q_UNUSED(name);

            Q_UNUSED(next);

            // TODO

            return Skip;

        }

    private:

        const ProjectedNodeTest::Ptr    m_test;

        const QXmlNodeModelIndex::Axis                m_axis;

    };

    class ProjectedPath : public ProjectedExpression

    {

    public:

        ProjectedPath(const ProjectedExpression::Ptr left,

                      const ProjectedExpression::Ptr right) : m_left(left),

                                                              m_right(right)

        {

            Q_ASSERT(m_left);

            Q_ASSERT(m_right);

        }

        virtual Action actionForElement(const QXmlName name,

                                        ProjectedExpression::Ptr &next) const

        {

            ProjectedExpression::Ptr &candidateNext = next;

            const Action a = m_left->actionForElement(name, candidateNext);

            if(a != Skip)

            {

                /* The test accepted it, so let's replace us with the new step. */

                next = candidateNext;

            }

            return a;

        }

    private:

        const ProjectedExpression::Ptr  m_left;

        const ProjectedExpression::Ptr  m_right;

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif