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

**

** Copyright (C) 2010 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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** contained in the Technology Preview License Agreement accompanying

** this package.

**

** 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

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

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

#include "qboolean_p.h"

#include "qcommonsequencetypes_p.h"

#include "qcommonvalues_p.h"

#include "qliteral_p.h"

#include "qinstanceof_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

InstanceOf::InstanceOf(const Expression::Ptr &operand,

                       const SequenceType::Ptr &tType) : SingleContainer(operand)

                                                       , m_targetType(tType)

{

    Q_ASSERT(m_targetType);

}

bool InstanceOf::evaluateEBV(const DynamicContext::Ptr &context) const

{

    const Item::Iterator::Ptr it(m_operand->evaluateSequence(context));

    Item item(it->next());

    unsigned int count = 1;

    if(!item)

        return m_targetType->cardinality().allowsEmpty();

    do

    {

        if(!m_targetType->itemType()->itemMatches(item))

            return false;

        if(count == 2 && !m_targetType->cardinality().allowsMany())

            return false;

        item = it->next();

        ++count;

    } while(item);

    return true;

}

Expression::Ptr InstanceOf::compress(const StaticContext::Ptr &context)

{

    const Expression::Ptr me(SingleContainer::compress(context));

    if(me != this || m_operand->has(DisableTypingDeduction))

        return me;

    const SequenceType::Ptr opType(m_operand->staticType());

    const ItemType::Ptr targetType(m_targetType->itemType());

    const ItemType::Ptr operandType(opType->itemType());

    if(m_targetType->cardinality().isMatch(opType->cardinality()))

    {

        if(*operandType == *CommonSequenceTypes::Empty || targetType->xdtTypeMatches(operandType))

            return wrapLiteral(CommonValues::BooleanTrue, context, this);

        else if(!operandType->xdtTypeMatches(targetType))

            return wrapLiteral(CommonValues::BooleanFalse, context, this);

    }

    /* Optimization: rule out the case where instance of will always fail. */

    return me;

}

SequenceType::Ptr InstanceOf::targetType() const

{

    return m_targetType;

}

SequenceType::Ptr InstanceOf::staticType() const

{

    return CommonSequenceTypes::ExactlyOneBoolean;

}

SequenceType::List InstanceOf::expectedOperandTypes() const

{

    SequenceType::List result;

    result.append(CommonSequenceTypes::ZeroOrMoreItems);

    return result;

}

ExpressionVisitorResult::Ptr InstanceOf::accept(const ExpressionVisitor::Ptr &visitor) const

{

    return visitor->visit(this);

}

QT_END_NAMESPACE