src/xmlpatterns/expr/qcastas.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 ** $QT_BEGIN_LICENSE:LGPL$
       
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    11 ** This file contains pre-release code and may not be distributed.
       
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    13 ** contained in the Technology Preview License Agreement accompanying
       
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    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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    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 #include "qitem_p.h"
       
    43 #include "qbuiltintypes_p.h"
       
    44 #include "qcardinalityverifier_p.h"
       
    45 #include "qcommonsequencetypes_p.h"
       
    46 #include "qemptysequence_p.h"
       
    47 #include "qgenericsequencetype_p.h"
       
    48 #include "qliteral_p.h"
       
    49 #include "qpatternistlocale_p.h"
       
    50 #include "qnamespaceresolver_p.h"
       
    51 #include "qqnameconstructor_p.h"
       
    52 #include "qqnamevalue_p.h"
       
    53 #include "qatomicstring_p.h"
       
    54 #include "qvalidationerror_p.h"
       
    55 
       
    56 #include "qcastas_p.h"
       
    57 
       
    58 QT_BEGIN_NAMESPACE
       
    59 
       
    60 using namespace QPatternist;
       
    61 
       
    62 CastAs::CastAs(const Expression::Ptr &source,
       
    63                const SequenceType::Ptr &tType) : SingleContainer(source),
       
    64                                                  m_targetType(tType)
       
    65 {
       
    66     Q_ASSERT(source);
       
    67     Q_ASSERT(tType);
       
    68     Q_ASSERT(!tType->cardinality().allowsMany());
       
    69     Q_ASSERT(tType->itemType()->isAtomicType());
       
    70 }
       
    71 
       
    72 Item CastAs::evaluateSingleton(const DynamicContext::Ptr &context) const
       
    73 {
       
    74     Q_ASSERT(context);
       
    75     const Item val(m_operand->evaluateSingleton(context));
       
    76 
       
    77     if(val)
       
    78         return cast(val, context);
       
    79     else
       
    80     {
       
    81         /* No item supplied, let's handle the cardinality part. */
       
    82 
       
    83         if(m_targetType->cardinality().allowsEmpty())
       
    84             return Item();
       
    85         else
       
    86         {
       
    87             Q_ASSERT(context);
       
    88             context->error(QtXmlPatterns::tr("Type error in cast, expected %1, "
       
    89                                              "received %2.")
       
    90                            .arg(formatType(Cardinality::exactlyOne()))
       
    91                            .arg(formatType(Cardinality::empty())),
       
    92                            ReportContext::XPTY0004, this);
       
    93             return Item();
       
    94         }
       
    95     }
       
    96 }
       
    97 
       
    98 Expression::Ptr CastAs::typeCheck(const StaticContext::Ptr &context,
       
    99                                   const SequenceType::Ptr &reqType)
       
   100 {
       
   101     checkTargetType(context);
       
   102     const SequenceType::Ptr seqt(m_operand->staticType());
       
   103     ItemType::Ptr t(seqt->itemType());
       
   104 
       
   105     /* Special case xs:QName */
       
   106     if(BuiltinTypes::xsQName->xdtTypeMatches(m_targetType->itemType()))
       
   107     {
       
   108         /* Ok, We're casting to xs:QName. */
       
   109         if(m_operand->is(IDStringValue)) /* A valid combination, let's do the cast. */
       
   110             return castToQName(context)->typeCheck(context, reqType);
       
   111         else if(BuiltinTypes::xsQName->xdtTypeMatches(t))
       
   112             return m_operand->typeCheck(context, reqType);
       
   113         else if(seqt->cardinality().isEmpty() && m_targetType->cardinality().allowsEmpty())
       
   114             return EmptySequence::create(this, context);
       
   115         else if(!(seqt->cardinality().isEmpty() && !m_targetType->cardinality().allowsEmpty()))
       
   116         {
       
   117             context->error(QtXmlPatterns::tr("When casting to %1 or types "
       
   118                                              "derived from it, the source "
       
   119                                              "value must be of the same type, "
       
   120                                              "or it must be a string literal. "
       
   121                                              "Type %2 is not allowed.")
       
   122                            .arg(formatType(context->namePool(), BuiltinTypes::xsQName))
       
   123                            .arg(formatType(context->namePool(), seqt)),
       
   124                            ReportContext::XPTY0004, this);
       
   125             return Expression::Ptr(this);
       
   126         }
       
   127     }
       
   128 
       
   129     const Expression::Ptr me(SingleContainer::typeCheck(context, reqType));
       
   130     /* Type may have changed, such as that atomization has been applied. */
       
   131     t = m_operand->staticType()->itemType();
       
   132 
       
   133     if(m_targetType->itemType()->xdtTypeMatches(t) &&
       
   134        !BuiltinTypes::xsDayTimeDuration->xdtTypeMatches(t) &&
       
   135        !BuiltinTypes::xsYearMonthDuration->xdtTypeMatches(t))
       
   136     { /* At least casting is superflorous. */
       
   137         if(m_operand->staticType()->cardinality().isMatch(m_targetType->cardinality()))
       
   138             return m_operand; /* The whole cast expression is redundant. */
       
   139         else
       
   140         { /* Only cardinality check is needed, rewrite to CardinalityVerifier. */
       
   141             return Expression::Ptr(new CardinalityVerifier(m_operand,
       
   142                                                            m_targetType->cardinality(),
       
   143                                                            ReportContext::FORG0001));
       
   144         }
       
   145     }
       
   146 
       
   147     /* Let the CastingPlatform look up its AtomicCaster. */
       
   148     prepareCasting(context, t);
       
   149 
       
   150     return me;
       
   151 }
       
   152 
       
   153 Expression::Ptr CastAs::compress(const StaticContext::Ptr &context)
       
   154 {
       
   155     /* Simplify casts to itself. */
       
   156     if(*m_targetType->itemType() == *m_operand->staticType()->itemType())
       
   157         return m_operand->compress(context);
       
   158     else
       
   159         return SingleContainer::compress(context);
       
   160 }
       
   161 
       
   162 Expression::Ptr CastAs::castToQName(const StaticContext::Ptr &context) const
       
   163 {
       
   164     /* Apply the whitespace facet by calling trimmed(). */
       
   165     /* We can assume m_operand is an Expression because this is a requirement
       
   166      * for casting to xs:QName. */
       
   167     const QString lexQName(m_operand->as<Literal>()->item().as<AtomicValue>()->stringValue().trimmed());
       
   168 
       
   169     const QXmlName
       
   170         expName(QNameConstructor::expandQName<StaticContext::Ptr,
       
   171                                               ReportContext::FORG0001,
       
   172                                               ReportContext::FONS0004>(lexQName,
       
   173                                                                        context,
       
   174                                                                        context->namespaceBindings(), this));
       
   175     return wrapLiteral(toItem(QNameValue::fromValue(context->namePool(), expName)), context, this);
       
   176 }
       
   177 
       
   178 SequenceType::Ptr CastAs::staticType() const
       
   179 {
       
   180     if(m_operand->staticType()->cardinality().allowsEmpty())
       
   181         return m_targetType;
       
   182     else
       
   183         return makeGenericSequenceType(m_targetType->itemType(),
       
   184                                        Cardinality::exactlyOne());
       
   185 }
       
   186 
       
   187 SequenceType::List CastAs::expectedOperandTypes() const
       
   188 {
       
   189     SequenceType::List result;
       
   190 
       
   191     if(m_targetType->cardinality().allowsEmpty())
       
   192         result.append(CommonSequenceTypes::ZeroOrOneAtomicType);
       
   193     else
       
   194         result.append(CommonSequenceTypes::ExactlyOneAtomicType);
       
   195 
       
   196     return result;
       
   197 }
       
   198 
       
   199 ExpressionVisitorResult::Ptr CastAs::accept(const ExpressionVisitor::Ptr &visitor) const
       
   200 {
       
   201     return visitor->visit(this);
       
   202 }
       
   203 
       
   204 QT_END_NAMESPACE