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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtXmlPatterns module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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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_Focus_H
#define Patternist_Focus_H
#include <private/qdelegatingdynamiccontext_p.h>
QT_BEGIN_NAMESPACE
namespace QPatternist
{
/**
* @short A DynamicContext that maintains the focus, a sequence
* of items.
*
* Focus implements both the outer and inner focus. The focus is one of
* the things that characterizes the XPath language. The focus is what's
* iterated over in a predicate, whose current item can be received
* via the context item expression, <tt>.</tt>(the dot),
* and whose size is retrievable via the function <tt>fn:last()</tt>.
*
* @author Frans Englich <frans.englich@nokia.com>
*/
class Focus : public DelegatingDynamicContext
{
public:
Focus(const DynamicContext::Ptr &prevContext);
virtual xsInteger contextPosition() const;
virtual Item contextItem() const;
virtual xsInteger contextSize();
virtual void setFocusIterator(const Item::Iterator::Ptr &it);
virtual Item::Iterator::Ptr focusIterator() const;
/**
* If there is no top level expression that sets the current item,
* the focus should be used. This implementation ensures that.
*/
virtual Item currentItem() const;
private:
Item::Iterator::Ptr m_focusIterator;
xsInteger m_contextSizeCached;
};
}
QT_END_NAMESPACE
#endif