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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_ExpressionFactory_H
51#define Patternist_ExpressionFactory_H
52
53#include <QXmlQuery>
54
55#include <private/qexpression_p.h>
56#include <private/qtokenizer_p.h>
57
58#include <QSharedData>
59#include <QUrl>
60
61QT_BEGIN_NAMESPACE
62
63class QIODevice;
64
65namespace QPatternist
66{
67 /**
68 * @short The central entry point for compiling expressions.
69 *
70 * @ingroup Patternist_expressions
71 * @author Frans Englich <frans.englich@nokia.com>
72 */
73 class Q_AUTOTEST_EXPORT ExpressionFactory : public QSharedData
74 {
75 public:
76 typedef QExplicitlySharedDataPointer<ExpressionFactory> Ptr;
77
78 /**
79 * @short This constructor cannot be synthesized since we
80 * use the Q_DISABLE_COPY macro.
81 */
82 inline ExpressionFactory()
83 {
84 }
85
86 virtual ~ExpressionFactory()
87 {
88 }
89
90 enum CompilationStage
91 {
92 QueryBodyInitial = 1,
93 QueryBodyTypeCheck = 1 << 1,
94 QueryBodyCompression = 1 << 2,
95 UserFunctionTypeCheck = 1 << 3,
96 UserFunctionCompression = 1 << 4,
97 GlobalVariableTypeCheck = 1 << 5
98 };
99
100 /**
101 * Creates a compiled representation of the XPath expression @p expr, with Static
102 * Context information supplied via @p context. This is for example whether the expression
103 * is an XPath 1.0 or XPath 2.0 expression, or what functions that are available.
104 *
105 * @p requiredType specifies what type results of the evaluating the expression
106 * must match. Passing CommonValues::ZeroOrMoreItems allows anything as result, while
107 * passing CommonSequenceTypes::EBV means anything but an Effective %Boolean Value extractable
108 * result is a type error, for example.
109 *
110 * @note An empty @p expr is an invalid XPath expression. It will be reported as such,
111 * but it is neverthless the caller's resonsibility to ensure that it's not that(since
112 * it is likely invalid already in the medium it was stored).
113 */
114 virtual Expression::Ptr createExpression(const QString &expr,
115 const StaticContext::Ptr &context,
116 const QXmlQuery::QueryLanguage lang,
117 const SequenceType::Ptr &requiredType,
118 const QUrl &queryURI,
119 const QXmlName &initialTemplateName);
120
121 virtual Expression::Ptr createExpression(QIODevice *const device,
122 const StaticContext::Ptr &context,
123 const QXmlQuery::QueryLanguage lang,
124 const SequenceType::Ptr &requiredType,
125 const QUrl &queryURI,
126 const QXmlName &initialTemplateName);
127
128 /**
129 * Finds the last paths of a set of paths(if any) and tells the Path
130 * so, such that it can generate the code for checking XPTY0018.
131 *
132 * Must be called before typeCheck() is called on the operand, since
133 * the typeCheck() uses the information for type checking.
134 */
135 static void registerLastPath(const Expression::Ptr &operand);
136
137 protected:
138 enum TemplateCompilationStage
139 {
140 TemplateInitial = 1,
141 TemplateTypeCheck = 1 << 1,
142 TemplateCompress = 1 << 2
143 };
144
145 /**
146 * This function is called by createExpression() each time
147 * after a pass on the AST has been completed. Under a typical
148 * compilation this function is thus called three times: after the initial
149 * build, after the Expression::typeCheck() stage, and after
150 * Expression::compress(). @p tree is the AST after each pass.
151 *
152 * This mechanism is currently used for debugging, since it provides a
153 * way of introspecting what the compilation process do to the tree. The
154 * current implementation do nothing.
155 */
156 virtual void processTreePass(const Expression::Ptr &tree,
157 const CompilationStage stage);
158
159 virtual void processTemplateRule(const Expression::Ptr &body,
160 const TemplatePattern::Ptr &pattern,
161 const QXmlName &mode,
162 const TemplateCompilationStage stage);
163
164 virtual void processNamedTemplate(const QXmlName &name,
165 const Expression::Ptr &tree,
166 const TemplateCompilationStage stage);
167
168 Expression::Ptr createExpression(const Tokenizer::Ptr &tokenizer,
169 const StaticContext::Ptr &context,
170 const QXmlQuery::QueryLanguage lang,
171 const SequenceType::Ptr &requiredType,
172 const QUrl &queryURI,
173 const QXmlName &initialTemplateName);
174 private:
175 Q_DISABLE_COPY(ExpressionFactory)
176 };
177}
178
179QT_END_NAMESPACE
180
181#endif
182

source code of qtxmlpatterns/src/xmlpatterns/expr/qexpressionfactory_p.h