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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** 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
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
//
// 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
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