src/xmlpatterns/expr/qgeneralcomparison_p.h
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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
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
    23 **
       
    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.
       
    27 **
       
    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 //
       
    43 //  W A R N I N G
       
    44 //  -------------
       
    45 //
       
    46 // This file is not part of the Qt API.  It exists purely as an
       
    47 // implementation detail.  This header file may change from version to
       
    48 // version without notice, or even be removed.
       
    49 //
       
    50 // We mean it.
       
    51 
       
    52 #ifndef Patternist_GeneralComparison_H
       
    53 #define Patternist_GeneralComparison_H
       
    54 
       
    55 #include "qatomiccomparator_p.h"
       
    56 #include "qpaircontainer_p.h"
       
    57 #include "qcomparisonplatform_p.h"
       
    58 
       
    59 QT_BEGIN_HEADER
       
    60 
       
    61 QT_BEGIN_NAMESPACE
       
    62 
       
    63 namespace QPatternist
       
    64 {
       
    65 
       
    66     /**
       
    67      * @short Implements XPath 2.0's general comparions, such as the <tt>=</tt> operator.
       
    68      *
       
    69      * ComparisonPlatform is inherited with @c protected scope because ComparisonPlatform
       
    70      * must access members of GeneralComparison.
       
    71      *
       
    72      * @see <a href="http://www.w3.org/TR/xpath20/#id-general-comparisons">XML Path Language
       
    73      * (XPath) 2.0, 3.5.2 General Comparisons</a>
       
    74      * @author Frans Englich <frans.englich@nokia.com>
       
    75      * @ingroup Patternist_expressions
       
    76      */
       
    77     class GeneralComparison : public PairContainer,
       
    78                               public ComparisonPlatform<GeneralComparison,
       
    79                                                         true /* We want to report errors. */,
       
    80                                                         AtomicComparator::AsGeneralComparison>
       
    81     {
       
    82     public:
       
    83         GeneralComparison(const Expression::Ptr &op1,
       
    84                           const AtomicComparator::Operator op,
       
    85                           const Expression::Ptr &op2,
       
    86                           const bool isBackwardsCompat = false);
       
    87 
       
    88         virtual bool evaluateEBV(const DynamicContext::Ptr &) const;
       
    89         virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
       
    90                                           const SequenceType::Ptr &reqType);
       
    91 
       
    92         virtual SequenceType::List expectedOperandTypes() const;
       
    93         virtual SequenceType::Ptr staticType() const;
       
    94 
       
    95         virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const;
       
    96 
       
    97         /**
       
    98          * @returns always IDGeneralComparison
       
    99          */
       
   100         virtual ID id() const;
       
   101 
       
   102         virtual QList<QExplicitlySharedDataPointer<OptimizationPass> > optimizationPasses() const;
       
   103 
       
   104         /**
       
   105          * @returns the operator that this GeneralComparison is using.
       
   106          */
       
   107         inline AtomicComparator::Operator operatorID() const
       
   108         {
       
   109             return m_operator;
       
   110         }
       
   111 
       
   112         /**
       
   113          * Overridden to optimize case-insensitive compares.
       
   114          */
       
   115         virtual Expression::Ptr compress(const StaticContext::Ptr &context);
       
   116 
       
   117     private:
       
   118         static inline void updateType(ItemType::Ptr &type,
       
   119                                       const Expression::Ptr &source);
       
   120         AtomicComparator::Ptr fetchGeneralComparator(Expression::Ptr &op1,
       
   121                                                      Expression::Ptr &op2,
       
   122                                                      const ReportContext::Ptr &context) const;
       
   123         bool generalCompare(const Item &op1,
       
   124                             const Item &op2,
       
   125                             const DynamicContext::Ptr &context) const;
       
   126 
       
   127         const AtomicComparator::Operator m_operator;
       
   128         const bool m_isBackwardsCompat;
       
   129     };
       
   130 }
       
   131 
       
   132 QT_END_NAMESPACE
       
   133 
       
   134 QT_END_HEADER
       
   135 
       
   136 #endif