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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_StackContextBase_H

#define Patternist_StackContextBase_H

#include <QVector>

#include "qdaytimeduration_p.h"

#include "qdelegatingdynamiccontext_p.h"

#include "qexpression_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

namespace QPatternist

{

    /**

     * @short Base class for all DynamicContext classes that needs to supply

     * variables. It has a new frame for local caches, position iterators,

     * expressions, range variables, template parameters but notably continues

     * to delegate global caches.

     *

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

     */

    template<typename TSuperClass>

    class StackContextBase : public TSuperClass

    {

    public:

        StackContextBase();

        /**

         * Construct a StackContextBase and passes @p prevContext to its super class. This

         * constructor is typically used when the super class is DelegatingDynamicContext.

         */

        StackContextBase(const DynamicContext::Ptr &prevContext);

        virtual void setRangeVariable(const VariableSlotID slotNumber,

                                      const Item &newValue);

        virtual Item rangeVariable(const VariableSlotID slotNumber) const;

        virtual void setExpressionVariable(const VariableSlotID slotNumber,

                                           const Expression::Ptr &newValue);

        virtual Expression::Ptr expressionVariable(const VariableSlotID slotNumber) const;

        virtual Item::Iterator::Ptr positionIterator(const VariableSlotID slot) const;

        virtual void setPositionIterator(const VariableSlotID slot,

                                         const Item::Iterator::Ptr &newValue);

        virtual ItemCacheCell &itemCacheCell(const VariableSlotID slot);

        virtual ItemSequenceCacheCell::Vector &itemSequenceCacheCells(const VariableSlotID slot);

        virtual DynamicContext::TemplateParameterHash &templateParameterStore();

    protected:

        /**

         * This function is protected, although it only is used in this class. I don't

         * know why it has to be, but it won't compile when private.

         */

        template<typename VectorType, typename UnitType>

        inline

        void setSlotVariable(const VariableSlotID slot,

                             const UnitType &newValue,

                             VectorType &container) const;

    private:

        Item::Vector                            m_rangeVariables;

        Expression::Vector                      m_expressionVariables;

        Item::Iterator::Vector                  m_positionIterators;

        ItemCacheCell::Vector                   m_itemCacheCells;

        ItemSequenceCacheCell::Vector           m_itemSequenceCacheCells;

        DynamicContext::TemplateParameterHash   m_templateParameterStore;

    };

    #include "qstackcontextbase.cpp"

    /**

     * @short A DynamicContext that creates a new scope for variables.

     *

     * This DynamicContext is used for recursive user function calls, for example.

     */

    typedef StackContextBase<DelegatingDynamicContext> StackContext;

}

QT_END_NAMESPACE

QT_END_HEADER

#endif