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39 | |
40 | // |
41 | // W A R N I N G |
42 | // ------------- |
43 | // |
44 | // This file is not part of the Qt API. It exists purely as an |
45 | // implementation detail. This header file may change from version to |
46 | // version without notice, or even be removed. |
47 | // |
48 | // We mean it. |
49 | |
50 | #ifndef Patternist_OrderBy_H |
51 | #define Patternist_OrderBy_H |
52 | |
53 | #include <private/qatomiccomparator_p.h> |
54 | #include <private/qcomparisonplatform_p.h> |
55 | #include <private/qsinglecontainer_p.h> |
56 | |
57 | QT_BEGIN_NAMESPACE |
58 | |
59 | namespace QPatternist |
60 | { |
61 | class ReturnOrderBy; |
62 | |
63 | /** |
64 | * @short Performs the sorting by being a parent to ForClause. |
65 | * |
66 | * The child of the ForClause is a ReturnOrderBy expression, which collects |
67 | * the sort keys and values. |
68 | * |
69 | * @author Frans Englich <frans.englich@nokia.com> |
70 | * @ingroup Patternist_expressions |
71 | */ |
72 | class OrderBy : public SingleContainer |
73 | { |
74 | public: |
75 | enum Stability |
76 | { |
77 | StableOrder, |
78 | UnstableOrder |
79 | }; |
80 | |
81 | /** |
82 | * This class is value based. |
83 | */ |
84 | class OrderSpec : public ComparisonPlatform<OrderBy::OrderSpec, |
85 | true, /* Yes, issue errors. */ |
86 | AtomicComparator::AsValueComparison> |
87 | { |
88 | public: |
89 | /** |
90 | * We want this guy to be public. |
91 | */ |
92 | using ComparisonPlatform<OrderBy::OrderSpec, true, AtomicComparator::AsValueComparison>::detailedFlexibleCompare; |
93 | |
94 | typedef QVector<OrderSpec> Vector; |
95 | |
96 | enum Direction |
97 | { |
98 | Ascending, |
99 | Descending |
100 | }; |
101 | |
102 | /** |
103 | * @short Default constructor, which is needed by QVector. |
104 | */ |
105 | inline OrderSpec() |
106 | : direction(Ascending), |
107 | orderingEmptySequence(StaticContext::Greatest) |
108 | { |
109 | } |
110 | |
111 | inline OrderSpec(const Direction dir, |
112 | const StaticContext::OrderingEmptySequence orderingEmpty) : direction(dir), |
113 | orderingEmptySequence(orderingEmpty) |
114 | { |
115 | } |
116 | |
117 | void prepare(const Expression::Ptr &source, |
118 | const StaticContext::Ptr &context); |
119 | |
120 | const SourceLocationReflection *actualReflection() const |
121 | { |
122 | return m_expr.data(); |
123 | } |
124 | |
125 | private: |
126 | Expression::Ptr m_expr; |
127 | |
128 | public: |
129 | /** |
130 | * We place these afterwards, such that m_expr gets aligned at the |
131 | * start of the address. |
132 | */ |
133 | Direction direction; |
134 | |
135 | StaticContext::OrderingEmptySequence orderingEmptySequence; |
136 | |
137 | inline AtomicComparator::Operator operatorID() const |
138 | { |
139 | return orderingEmptySequence == StaticContext::Least ? AtomicComparator::OperatorLessThanNaNLeast |
140 | : AtomicComparator::OperatorLessThanNaNGreatest; |
141 | } |
142 | |
143 | }; |
144 | |
145 | OrderBy(const Stability stability, |
146 | const OrderSpec::Vector &orderSpecs, |
147 | const Expression::Ptr &operand, |
148 | ReturnOrderBy *const returnOrderBy); |
149 | |
150 | virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const; |
151 | virtual SequenceType::Ptr staticType() const; |
152 | virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context, |
153 | const SequenceType::Ptr &reqType); |
154 | virtual Expression::Ptr compress(const StaticContext::Ptr &context); |
155 | virtual SequenceType::List expectedOperandTypes() const; |
156 | virtual ExpressionVisitorResult::Ptr accept(const ExpressionVisitor::Ptr &visitor) const; |
157 | |
158 | inline Item::Iterator::Ptr mapToSequence(const Item &i, |
159 | const DynamicContext::Ptr &context) const; |
160 | virtual Properties properties() const; |
161 | |
162 | private: |
163 | /** |
164 | * Needed when calling makeSequenceMappingIterator(). |
165 | */ |
166 | typedef QExplicitlySharedDataPointer<const OrderBy> ConstPtr; |
167 | |
168 | const Stability m_stability; |
169 | OrderSpec::Vector m_orderSpecs; |
170 | ReturnOrderBy *const m_returnOrderBy; |
171 | }; |
172 | |
173 | /* TODO Q_DECLARE_TYPEINFO(OrderBy::OrderSpec, Q_MOVABLE_TYPE); Breaks, |
174 | * probably because it's nested. */ |
175 | } |
176 | |
177 | QT_END_NAMESPACE |
178 | |
179 | #endif |
180 | |