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

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** Copyright (C) 2009 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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** No Commercial Usage

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** contained in the Technology Preview License Agreement accompanying

** this package.

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** GNU Lesser General Public License Usage

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** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

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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_DynamicContext_H

#define Patternist_DynamicContext_H

#include "qautoptr_p.h"

#include "qcachecells_p.h"

#include "qexternalvariableloader_p.h"

#include "qitem_p.h"

#include "qnamepool_p.h"

#include "qnodebuilder_p.h"

#include "qprimitives_p.h"

#include "qreportcontext_p.h"

#include "qresourceloader_p.h"

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

class QDateTime;

template<typename T> class QVector;

namespace QPatternist

{

    class DayTimeDuration;

    class Expression;

    class TemplateMode;

    /**

     * @short Carries information and facilities used at runtime, and hence

     * provides a state for that stage in a thread-safe manner.

     *

     * @see <a href="http://www.w3.org/TR/xquery/#eval_context">XQuery

     * 1.0: An XML Query Language, 2.1.2 Dynamic Context</a>

     * @see <a href="http://www.w3.org/TR/xquery/#id-dynamic-evaluation">XQuery

     * 1.0: An XML Query Language, 2.2.3.2 Dynamic Evaluation Phase</a>

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

     */

    class DynamicContext : public ReportContext

    {

    public:

        /**

         * @short Carries template parameters at runtime.

         *

         * The key is the name of the parameter, and the value the Expression

         * which supplies the value.

         */

        typedef QHash<QXmlName, QExplicitlySharedDataPointer<Expression> > TemplateParameterHash;

        typedef QExplicitlySharedDataPointer<DynamicContext> Ptr;

        virtual ~DynamicContext()

        {

        }

        /**

         * This function intentionally returns by reference.

         *

         * @see globalItemCacheCell()

         */

        virtual ItemCacheCell &itemCacheCell(const VariableSlotID slot) = 0;

        /**

         * This function intentionally returns by reference.

         *

         * @see globalItemSequenceCacheCells

         */

        virtual ItemSequenceCacheCell::Vector &itemSequenceCacheCells(const VariableSlotID slot) = 0;

        virtual xsInteger contextPosition() const = 0;

        virtual Item contextItem() const = 0;

        virtual xsInteger contextSize() = 0;

        virtual void setRangeVariable(const VariableSlotID slot,

                                      const Item &newValue) = 0;

        virtual Item rangeVariable(const VariableSlotID slot) const = 0;

        virtual void setExpressionVariable(const VariableSlotID slot,

                                           const QExplicitlySharedDataPointer<Expression> &newValue) = 0;

        virtual QExplicitlySharedDataPointer<Expression>

        expressionVariable(const VariableSlotID slot) const = 0;

        virtual Item::Iterator::Ptr positionIterator(const VariableSlotID slot) const = 0;

        virtual void setPositionIterator(const VariableSlotID slot,

                                         const Item::Iterator::Ptr &newValue) = 0;

        virtual void setFocusIterator(const Item::Iterator::Ptr &it) = 0;

        virtual Item::Iterator::Ptr focusIterator() const = 0;

        virtual QExplicitlySharedDataPointer<DayTimeDuration> implicitTimezone() const = 0;

        virtual QDateTime currentDateTime() const = 0;

        virtual QAbstractXmlReceiver *outputReceiver() const = 0;

        virtual NodeBuilder::Ptr nodeBuilder(const QUrl &baseURI) const = 0;

        virtual ResourceLoader::Ptr resourceLoader() const = 0;

        virtual ExternalVariableLoader::Ptr externalVariableLoader() const = 0;

        virtual NamePool::Ptr namePool() const = 0;

        /**

         * @short Returns the item that @c fn:current() returns.

         *

         * Hence, this is not the focus, and very different from the focus.

         *

         * @see CurrentItemStore

         * @see CurrentFN

         */

        virtual Item currentItem() const = 0;

        DynamicContext::Ptr createFocus();

        DynamicContext::Ptr createStack();

        DynamicContext::Ptr createReceiverContext(QAbstractXmlReceiver *const receiver);

        /**

         * Whenever a tree gets built, this function is called. DynamicContext

         * has the responsibility of keeping a copy of @p nm, such that it

         * doesn't go out of scope, since no one else will reference @p nm.

         *

         * I think this is currently only used for temporary node trees. In

         * other cases they are stored in the ExternalResourceLoader.

         *

         * The caller guarantees that @p nm is not @c null.

         */

        virtual void addNodeModel(const QAbstractXmlNodeModel::Ptr &nm) = 0;

        /**

         * Same as itemCacheCell(), but is only used for global varibles. This

         * is needed because sometimes stack frames needs to be created for

         * other kinds of variables(such as in the case of user function

         * calls), while the global variable(s) needs to continue to use the

         * same cache, instead of one for each new stack frame, typically an

         * instance of StackContextBase.

         *

         * This has two effects:

         *

         * - It's an optimization. Instead of that a global variable gets evaluated each

         * time a user function is called, think recursive functions, it's done

         * only once.

         * - Query stability, hence affects things like node identity and

         * therefore conformance. Hence affects for instance what nodes a query

         * returns, since node identity affect node deduplication.

         */

        virtual ItemCacheCell &globalItemCacheCell(const VariableSlotID slot) = 0;

        /**

         * @short When a template is called, this member carries the template

         * parameters.

         *

         * Hence this is similar to the other variable stack functions such as

         * rangeVariable() and expressionVariable(), the difference being that

         * the order of template parameters as well as its arguments can appear

         * in arbitrary order. Hence the name is used to make the order

         * insignificant.

         */

        virtual TemplateParameterHash &templateParameterStore() = 0;

        /**

         * Same as itemSequenceCacheCells() but applies only for global

         * variables.

         *

         * @see globalItemCacheCell()

         */

        virtual ItemSequenceCacheCell::Vector &globalItemSequenceCacheCells(const VariableSlotID slot) = 0;

        /**

         * @short Returns the previous DynamicContext. If this context is the

         * top-level one, @c null is returned.

         */

        virtual DynamicContext::Ptr previousContext() const = 0;

        /**

         * @short Returns the current template mode that is in effect.

         *

         * If @c null is returned, it means that the default mode should be

         * used as the current mode.

         */

        virtual QExplicitlySharedDataPointer<TemplateMode> currentTemplateMode() const = 0;

    };

}

QT_END_NAMESPACE

QT_END_HEADER

#endif