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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.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qcommonsequencetypes_p.h"
#include "qexceptiterator_p.h"
#include "qgenericsequencetype_p.h"
#include "qintersectiterator_p.h"
#include "qitemmappingiterator_p.h"
#include "qnodesort_p.h"
#include "qunioniterator_p.h"
#include "qcombinenodes_p.h"
QT_BEGIN_NAMESPACE
using namespace QPatternist;
CombineNodes::CombineNodes(const Expression::Ptr &operand1,
const Operator op,
const Expression::Ptr &operand2) : PairContainer(operand1, operand2),
m_operator(op)
{
Q_ASSERT(op == Union ||
op == Except ||
op == Intersect);
}
Item::Iterator::Ptr CombineNodes::evaluateSequence(const DynamicContext::Ptr &context) const
{
const Item::Iterator::Ptr op1(m_operand1->evaluateSequence(context));
const Item::Iterator::Ptr op2(m_operand2->evaluateSequence(context));
switch(m_operator)
{
case Intersect:
return Item::Iterator::Ptr(new IntersectIterator(op1, op2));
case Except:
return Item::Iterator::Ptr(new ExceptIterator(op1, op2));
default:
{
Q_ASSERT(m_operator == Union);
return Item::Iterator::Ptr(new UnionIterator(op1, op2));
}
}
}
Item CombineNodes::evaluateSingleton(const DynamicContext::Ptr &context) const
{
return evaluateSequence(context)->next();
}
Expression::Ptr CombineNodes::typeCheck(const StaticContext::Ptr &context,
const SequenceType::Ptr &reqType)
{
const Expression::Ptr me(PairContainer::typeCheck(context, reqType));
m_operand1 = NodeSortExpression::wrapAround(m_operand1, context);
m_operand2 = NodeSortExpression::wrapAround(m_operand2, context);
return me;
}
bool CombineNodes::evaluateEBV(const DynamicContext::Ptr &context) const
{
/* If it's the union operator, we can possibly avoid
* evaluating the second operand. */
if(m_operator == Union)
{
return m_operand1->evaluateEBV(context) ||
m_operand2->evaluateEBV(context);
}
else
return PairContainer::evaluateEBV(context);
}
QString CombineNodes::displayName(const Operator op)
{
switch(op)
{
case Intersect:
return QLatin1String("intersect");
case Except:
return QLatin1String("except");
default:
{
Q_ASSERT(op == Union);
return QLatin1String("union");
}
}
}
SequenceType::Ptr CombineNodes::staticType() const
{
const SequenceType::Ptr t1(m_operand1->staticType());
const SequenceType::Ptr t2(m_operand2->staticType());
Cardinality card;
/* Optimization: the cardinality can be better inferred for
* Intersect and Except, although it's not trivial code. */
if(m_operator == Union)
card = t1->cardinality() | t2->cardinality();
else /* Except. */
card = Cardinality::zeroOrMore();
return makeGenericSequenceType(t1->itemType() | t2->itemType(), card);
}
SequenceType::List CombineNodes::expectedOperandTypes() const
{
SequenceType::List result;
result.append(CommonSequenceTypes::ZeroOrMoreNodes);
result.append(CommonSequenceTypes::ZeroOrMoreNodes);
return result;
}
CombineNodes::Operator CombineNodes::operatorID() const
{
return m_operator;
}
ExpressionVisitorResult::Ptr CombineNodes::accept(const ExpressionVisitor::Ptr &visitor) const
{
return visitor->visit(this);
}
Expression::ID CombineNodes::id() const
{
return IDCombineNodes;
}
QT_END_NAMESPACE
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