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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          */
operatorID()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
137