src/xmlpatterns/janitors/qcardinalityverifier.cpp
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     1 /****************************************************************************
       
     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
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
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    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 #include "qcommonsequencetypes_p.h"
       
    43 #include "qcommonvalues_p.h"
       
    44 #include "qgenericpredicate_p.h"
       
    45 #include "qgenericsequencetype_p.h"
       
    46 #include "qinsertioniterator_p.h"
       
    47 #include "qpatternistlocale_p.h"
       
    48 
       
    49 #include "qcardinalityverifier_p.h"
       
    50 
       
    51 QT_BEGIN_NAMESPACE
       
    52 
       
    53 using namespace QPatternist;
       
    54 
       
    55 QString CardinalityVerifier::wrongCardinality(const Cardinality &req,
       
    56                                               const Cardinality &got)
       
    57 {
       
    58     return QtXmlPatterns::tr("Required cardinality is %1; got cardinality %2.")
       
    59                 .arg(formatType(req), formatType(got));
       
    60 }
       
    61 
       
    62 Expression::Ptr CardinalityVerifier::verifyCardinality(const Expression::Ptr &operand,
       
    63                                                        const Cardinality &requiredCard,
       
    64                                                        const StaticContext::Ptr &context,
       
    65                                                        const ReportContext::ErrorCode code)
       
    66 {
       
    67     const Cardinality opCard(operand->staticType()->cardinality());
       
    68 
       
    69     if(requiredCard.isMatch(opCard))
       
    70         return operand;
       
    71     else if(requiredCard.canMatch(opCard))
       
    72         return Expression::Ptr(new CardinalityVerifier(operand, requiredCard, code));
       
    73     else if(context->compatModeEnabled() &&
       
    74             !opCard.isEmpty())
       
    75     {
       
    76         return GenericPredicate::createFirstItem(operand);
       
    77     }
       
    78     else
       
    79     {
       
    80         /* Sequences within this cardinality can never match. */
       
    81         context->error(wrongCardinality(requiredCard, opCard), code, operand.data());
       
    82         return operand;
       
    83     }
       
    84 }
       
    85 
       
    86 CardinalityVerifier::CardinalityVerifier(const Expression::Ptr &operand,
       
    87                                          const Cardinality &card,
       
    88                                          const ReportContext::ErrorCode code)
       
    89                                          : SingleContainer(operand),
       
    90                                            m_reqCard(card),
       
    91                                            m_allowsMany(operand->staticType()->cardinality().allowsMany()),
       
    92                                            m_errorCode(code)
       
    93 {
       
    94     Q_ASSERT_X(m_reqCard != Cardinality::zeroOrMore(), Q_FUNC_INFO,
       
    95                "It makes no sense to use CardinalityVerifier for cardinality zero-or-more.");
       
    96 }
       
    97 
       
    98 Item::Iterator::Ptr CardinalityVerifier::evaluateSequence(const DynamicContext::Ptr &context) const
       
    99 {
       
   100     const Item::Iterator::Ptr it(m_operand->evaluateSequence(context));
       
   101     const Item next(it->next());
       
   102 
       
   103     if(next)
       
   104     {
       
   105         const Item next2(it->next());
       
   106 
       
   107         if(next2)
       
   108         {
       
   109             if(m_reqCard.allowsMany())
       
   110             {
       
   111                 Item::List start;
       
   112                 start.append(next);
       
   113                 start.append(next2);
       
   114 
       
   115                 return Item::Iterator::Ptr(new InsertionIterator(it, 1, makeListIterator(start)));
       
   116             }
       
   117             else
       
   118             {
       
   119                 context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()), m_errorCode, this);
       
   120                 return CommonValues::emptyIterator;
       
   121             }
       
   122         }
       
   123         else
       
   124         {
       
   125             /* We might be instantiated for the empty sequence. */
       
   126             if(m_reqCard.isEmpty())
       
   127             {
       
   128                 context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()), m_errorCode, this);
       
   129                 return CommonValues::emptyIterator;
       
   130             }
       
   131             else
       
   132                 return makeSingletonIterator(next);
       
   133         }
       
   134     }
       
   135     else
       
   136     {
       
   137         if(m_reqCard.allowsEmpty())
       
   138             return CommonValues::emptyIterator;
       
   139         else
       
   140         {
       
   141             context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()), m_errorCode, this);
       
   142             return CommonValues::emptyIterator;
       
   143         }
       
   144     }
       
   145 }
       
   146 
       
   147 Item CardinalityVerifier::evaluateSingleton(const DynamicContext::Ptr &context) const
       
   148 {
       
   149     if(m_allowsMany)
       
   150     {
       
   151         const Item::Iterator::Ptr it(m_operand->evaluateSequence(context));
       
   152         const Item item(it->next());
       
   153 
       
   154         if(item)
       
   155         {
       
   156             if(it->next())
       
   157             {
       
   158                 context->error(wrongCardinality(m_reqCard, Cardinality::twoOrMore()),
       
   159                                m_errorCode, this);
       
   160                 return Item();
       
   161             }
       
   162             else
       
   163                 return item;
       
   164         }
       
   165         else if(m_reqCard.allowsEmpty())
       
   166             return Item();
       
   167         else
       
   168         {
       
   169             context->error(wrongCardinality(m_reqCard), m_errorCode, this);
       
   170             return Item();
       
   171         }
       
   172     }
       
   173     else
       
   174     {
       
   175         const Item item(m_operand->evaluateSingleton(context));
       
   176 
       
   177         if(item)
       
   178             return item;
       
   179         else if(m_reqCard.allowsEmpty())
       
   180             return Item();
       
   181         else
       
   182         {
       
   183             context->error(wrongCardinality(m_reqCard), m_errorCode, this);
       
   184             return Item();
       
   185         }
       
   186     }
       
   187 }
       
   188 
       
   189 const SourceLocationReflection *CardinalityVerifier::actualReflection() const
       
   190 {
       
   191     return m_operand->actualReflection();
       
   192 }
       
   193 
       
   194 Expression::Ptr CardinalityVerifier::compress(const StaticContext::Ptr &context)
       
   195 {
       
   196     if(m_reqCard.isMatch(m_operand->staticType()->cardinality()))
       
   197         return m_operand->compress(context);
       
   198     else
       
   199         return SingleContainer::compress(context);
       
   200 }
       
   201 
       
   202 SequenceType::List CardinalityVerifier::expectedOperandTypes() const
       
   203 {
       
   204     SequenceType::List result;
       
   205     result.append(CommonSequenceTypes::ZeroOrMoreItems);
       
   206     return result;
       
   207 }
       
   208 
       
   209 SequenceType::Ptr CardinalityVerifier::staticType() const
       
   210 {
       
   211     return makeGenericSequenceType(m_operand->staticType()->itemType(), m_reqCard);
       
   212 }
       
   213 
       
   214 ExpressionVisitorResult::Ptr CardinalityVerifier::accept(const ExpressionVisitor::Ptr &visitor) const
       
   215 {
       
   216     return visitor->visit(this);
       
   217 }
       
   218 
       
   219 Expression::ID CardinalityVerifier::id() const
       
   220 {
       
   221     return IDCardinalityVerifier;
       
   222 }
       
   223 
       
   224 QT_END_NAMESPACE