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     2 **

     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

     4 ** All rights reserved.

     5 ** Contact: Nokia Corporation (qt-info@nokia.com)

     6 **

     7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit.

     8 **

     9 ** $QT_BEGIN_LICENSE:LGPL$

    10 ** No Commercial Usage

    11 ** This file contains pre-release code and may not be distributed.

    12 ** You may use this file in accordance with the terms and conditions

    13 ** contained in the Technology Preview License Agreement accompanying

    14 ** this package.

    15 **

    16 ** GNU Lesser General Public License Usage

    17 ** Alternatively, this file may be used under the terms of the GNU Lesser

    18 ** General Public License version 2.1 as published by the Free Software

    19 ** Foundation and appearing in the file LICENSE.LGPL included in the

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

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

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    24 ** In addition, as a special exception, Nokia gives you certain additional

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    38 ** $QT_END_LICENSE$

    39 **

    40 ****************************************************************************/

    41 

    42 #include "qboolean_p.h"

    43 #include "qcommonsequencetypes_p.h"

    44 #include "qcommonvalues_p.h"

    45 #include "qliteral_p.h"

    46 

    47 #include "qinstanceof_p.h"

    48 

    49 QT_BEGIN_NAMESPACE

    50 

    51 using namespace QPatternist;

    52 

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

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

    55                                                        , m_targetType(tType)

    56 {

    57     Q_ASSERT(m_targetType);

    58 }

    59 

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

    61 {

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

    63     Item item(it->next());

    64     unsigned int count = 1;

    65 

    66     if(!item)

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

    68 

    69     do

    70     {

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

    72             return false;

    73 

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

    75             return false;

    76 

    77         item = it->next();

    78         ++count;

    79     } while(item);

    80 

    81     return true;

    82 }

    83 

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

    85 {

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

    87 

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

    89         return me;

    90 

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

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

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

    94 

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

    96     {

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

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

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

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

   101     }

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

   103 

   104     return me;

   105 }

   106 

   107 SequenceType::Ptr InstanceOf::targetType() const

   108 {

   109     return m_targetType;

   110 }

   111 

   112 SequenceType::Ptr InstanceOf::staticType() const

   113 {

   114     return CommonSequenceTypes::ExactlyOneBoolean;

   115 }

   116 

   117 SequenceType::List InstanceOf::expectedOperandTypes() const

   118 {

   119     SequenceType::List result;

   120     result.append(CommonSequenceTypes::ZeroOrMoreItems);

   121     return result;

   122 }

   123 

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

   125 {

   126     return visitor->visit(this);

   127 }

   128 

   129 QT_END_NAMESPACE