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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (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 either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** 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 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@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