src/xmlpatterns/expr/qexpressionfactory_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_ExpressionFactory_H
       
    53 #define Patternist_ExpressionFactory_H
       
    54 
       
    55 #include <QXmlQuery>
       
    56 
       
    57 #include "qexpression_p.h"
       
    58 #include "qtokenizer_p.h"
       
    59 
       
    60 #include <QSharedData>
       
    61 #include <QUrl>
       
    62 
       
    63 QT_BEGIN_HEADER
       
    64 
       
    65 QT_BEGIN_NAMESPACE
       
    66 
       
    67 class QIODevice;
       
    68 
       
    69 namespace QPatternist
       
    70 {
       
    71     /**
       
    72      * @short The central entry point for compiling expressions.
       
    73      *
       
    74      * @ingroup Patternist_expressions
       
    75      * @author Frans Englich <frans.englich@nokia.com>
       
    76      */
       
    77     class Q_AUTOTEST_EXPORT ExpressionFactory : public QSharedData
       
    78     {
       
    79     public:
       
    80         typedef QExplicitlySharedDataPointer<ExpressionFactory> Ptr;
       
    81 
       
    82         /**
       
    83          * @short This constructor cannot be synthesized since we
       
    84          * use the Q_DISABLE_COPY macro.
       
    85          */
       
    86         inline ExpressionFactory()
       
    87         {
       
    88         }
       
    89 
       
    90         virtual ~ExpressionFactory()
       
    91         {
       
    92         }
       
    93 
       
    94         enum CompilationStage
       
    95         {
       
    96             QueryBodyInitial        = 1,
       
    97             QueryBodyTypeCheck      = 1 << 1,
       
    98             QueryBodyCompression    = 1 << 2,
       
    99             UserFunctionTypeCheck   = 1 << 3,
       
   100             UserFunctionCompression = 1 << 4,
       
   101             GlobalVariableTypeCheck = 1 << 5
       
   102         };
       
   103 
       
   104         /**
       
   105          * Creates a compiled representation of the XPath expression @p expr, with Static
       
   106          * Context information supplied via @p context. This is for example whether the expression
       
   107          * is an XPath 1.0 or XPath 2.0 expression, or what functions that are available.
       
   108          *
       
   109          * @p requiredType specifies what type results of the evaluating the expression
       
   110          * must match. Passing CommonValues::ZeroOrMoreItems allows anything as result, while
       
   111          * passing CommonSequenceTypes::EBV means anything but an Effective %Boolean Value extractable
       
   112          * result is a type error, for example.
       
   113          *
       
   114          * @note An empty @p expr is an invalid XPath expression. It will be reported as such,
       
   115          * but it is neverthless the caller's resonsibility to ensure that it's not that(since
       
   116          * it is likely invalid already in the medium it was stored).
       
   117          */
       
   118         virtual Expression::Ptr createExpression(const QString &expr,
       
   119                                                  const StaticContext::Ptr &context,
       
   120                                                  const QXmlQuery::QueryLanguage lang,
       
   121                                                  const SequenceType::Ptr &requiredType,
       
   122                                                  const QUrl &queryURI,
       
   123                                                  const QXmlName &initialTemplateName);
       
   124 
       
   125         virtual Expression::Ptr createExpression(QIODevice *const device,
       
   126                                                  const StaticContext::Ptr &context,
       
   127                                                  const QXmlQuery::QueryLanguage lang,
       
   128                                                  const SequenceType::Ptr &requiredType,
       
   129                                                  const QUrl &queryURI,
       
   130                                                  const QXmlName &initialTemplateName);
       
   131 
       
   132         /**
       
   133          * Finds the last paths of a set of paths(if any) and tells the Path
       
   134          * so, such that it can generate the code for checking XPTY0018.
       
   135          *
       
   136          * Must be called before typeCheck() is called on the operand, since
       
   137          * the typeCheck() uses the information for type checking.
       
   138          */
       
   139         static void registerLastPath(const Expression::Ptr &operand);
       
   140 
       
   141     protected:
       
   142         enum TemplateCompilationStage
       
   143         {
       
   144             TemplateInitial         = 1,
       
   145             TemplateTypeCheck       = 1 << 1,
       
   146             TemplateCompress        = 1 << 2
       
   147         };
       
   148 
       
   149         /**
       
   150          * This function is called by createExpression() each time
       
   151          * after a pass on the AST has been completed. Under a typical
       
   152          * compilation this function is thus called three times: after the initial
       
   153          * build, after the Expression::typeCheck() stage, and after
       
   154          * Expression::compress(). @p tree is the AST after each pass.
       
   155          *
       
   156          * This mechanism is currently used for debugging, since it provides a
       
   157          * way of introspecting what the compilation process do to the tree. The
       
   158          * current implementation do nothing.
       
   159          */
       
   160         virtual void processTreePass(const Expression::Ptr &tree,
       
   161                                      const CompilationStage stage);
       
   162 
       
   163         virtual void processTemplateRule(const Expression::Ptr &body,
       
   164                                          const TemplatePattern::Ptr &pattern,
       
   165                                          const QXmlName &mode,
       
   166                                          const TemplateCompilationStage stage);
       
   167 
       
   168         virtual void processNamedTemplate(const QXmlName &name,
       
   169                                           const Expression::Ptr &tree,
       
   170                                           const TemplateCompilationStage stage);
       
   171 
       
   172         Expression::Ptr createExpression(const Tokenizer::Ptr &tokenizer,
       
   173                                          const StaticContext::Ptr &context,
       
   174                                          const QXmlQuery::QueryLanguage lang,
       
   175                                          const SequenceType::Ptr &requiredType,
       
   176                                          const QUrl &queryURI,
       
   177                                          const QXmlName &initialTemplateName);
       
   178     private:
       
   179         Q_DISABLE_COPY(ExpressionFactory)
       
   180     };
       
   181 }
       
   182 
       
   183 QT_END_NAMESPACE
       
   184 
       
   185 QT_END_HEADER
       
   186 
       
   187 #endif