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

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** Copyright (C) 2009 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.

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

#include "qatomictype_p.h"

#include "qitem_p.h"

#include "qboolean_p.h"

#include "qbuiltintypes_p.h"

#include "qcommonsequencetypes_p.h"

#include "qcommonvalues_p.h"

#include "qliteral_p.h"

#include "qcastableas_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

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

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

                                                         m_targetType(tType)

{

    Q_ASSERT(tType);

    Q_ASSERT(!tType->cardinality().allowsMany());

    Q_ASSERT(tType->itemType()->isAtomicType());

}

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

{

    Item item;

    if(m_operand->staticType()->cardinality().allowsMany())

    {

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

        item = it->next();

        if(it->next())

            return false;

    }

    else

        item = m_operand->evaluateSingleton(context);

    if(item)

        return !cast(item, context).as<AtomicValue>()->hasError();

    else

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

}

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

{

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

    if(me != this) /* We already managed to const fold, how convenient. */

        return me;

    const AtomicType::Ptr t(m_targetType->itemType());

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

    /* Casting to these always succeeds, assuming the cardinality also matches,

     * although the cardinality can fail. */

    if((   *t == *BuiltinTypes::xsString

        || *t == *BuiltinTypes::xsUntypedAtomic

        || *t == *opType->itemType())

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

    {

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

    }

    else

        return me;

}

Expression::Ptr CastableAs::typeCheck(const StaticContext::Ptr &context,

                                      const SequenceType::Ptr &reqType)

{

    checkTargetType(context);

    const Expression::Ptr me(SingleContainer::typeCheck(context, reqType));

    return me;

    if(BuiltinTypes::xsQName->xdtTypeMatches(m_targetType->itemType()))

    {

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

        /* We can cast a string literal, an xs:QName value, and an

         * empty sequence(if empty is allowed), to xs:QName. */

        if(m_operand->is(IDStringValue) ||

           BuiltinTypes::xsQName->xdtTypeMatches(seqt->itemType()) ||

           (*seqt->itemType() == *CommonSequenceTypes::Empty && m_targetType->cardinality().allowsEmpty()))

        {

            return wrapLiteral(CommonValues::BooleanTrue, context, this)->typeCheck(context, reqType);

        }

        else

            return wrapLiteral(CommonValues::BooleanFalse, context, this)->typeCheck(context, reqType);

    }

    else

    {

        /* Let the CastingPlatform look up its AtomicCaster. */

        prepareCasting(context, m_operand->staticType()->itemType());

        return me;

    }

}

SequenceType::List CastableAs::expectedOperandTypes() const

{

    SequenceType::List result;

    result.append(CommonSequenceTypes::ZeroOrMoreAtomicTypes);

    return result;

}

SequenceType::Ptr CastableAs::staticType() const

{

    return CommonSequenceTypes::ExactlyOneBoolean;

}

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

{

    return visitor->visit(this);

}

QT_END_NAMESPACE