src/xmlpatterns/expr/qvariabledeclaration_p.h
changeset 0 1918ee327afb
child 4 3b1da2848fc7
equal deleted inserted replaced
-1:000000000000 0:1918ee327afb
       
     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_VariableDeclaration_H
       
    53 #define Patternist_VariableDeclaration_H
       
    54 
       
    55 #include <QSharedData>
       
    56 
       
    57 #include "qexpression_p.h"
       
    58 #include "qpatternistlocale_p.h"
       
    59 #include "qvariablereference_p.h"
       
    60 
       
    61 QT_BEGIN_HEADER
       
    62 
       
    63 QT_BEGIN_NAMESPACE
       
    64 
       
    65 template<typename T> class QStack;
       
    66 
       
    67 namespace QPatternist
       
    68 {
       
    69     /**
       
    70      * @short Represents a declared variable. Only used at
       
    71      * the compilation stage.
       
    72      *
       
    73      * @see FunctionArgument
       
    74      * @author Frans Englich <frans.englich@nokia.com>
       
    75      * @ingroup Patternist_expressions
       
    76      */
       
    77     class VariableDeclaration : public QSharedData
       
    78     {
       
    79     public:
       
    80         typedef QExplicitlySharedDataPointer<VariableDeclaration> Ptr;
       
    81         typedef QStack<VariableDeclaration::Ptr> Stack;
       
    82         typedef QList<VariableDeclaration::Ptr> List;
       
    83 
       
    84         /**
       
    85          * @short The key is the variable name.
       
    86          */
       
    87         typedef QHash<QXmlName, VariableDeclaration::Ptr> Hash;
       
    88 
       
    89         enum Type
       
    90         {
       
    91             RangeVariable,
       
    92             ExpressionVariable,
       
    93             FunctionArgument,
       
    94             PositionalVariable,
       
    95             TemplateParameter,
       
    96 
       
    97             /**
       
    98              * A global variable is always an external variable, but it is
       
    99              * cached differently.
       
   100              *
       
   101              * @see DynamicContext::globalItemCacheCell()
       
   102              */
       
   103             GlobalVariable,
       
   104 
       
   105             /**
       
   106              * External variables doesn't use slots, that's a big difference
       
   107              * compared to the other types.
       
   108              */
       
   109             ExternalVariable
       
   110         };
       
   111 
       
   112         /**
       
   113          * Creates a VariableDeclaration.
       
   114          *
       
   115          * @p sourceExpr and @p seqType may be @c null.
       
   116          */
       
   117         VariableDeclaration(const QXmlName n,
       
   118                             const VariableSlotID varSlot,
       
   119                             const Type t,
       
   120                             const SequenceType::Ptr &seqType) : name(n)
       
   121                                                               , slot(varSlot)
       
   122                                                               , type(t)
       
   123                                                               , sequenceType(seqType)
       
   124                                                               , canSourceRewrite(true)
       
   125         {
       
   126             Q_ASSERT(!name.isNull());
       
   127             Q_ASSERT(t == ExternalVariable || t == TemplateParameter || varSlot > -1);
       
   128         }
       
   129 
       
   130         inline bool isUsed() const
       
   131         {
       
   132             return !references.isEmpty();
       
   133         }
       
   134 
       
   135         inline const Expression::Ptr &expression() const
       
   136         {
       
   137             return m_expression;
       
   138         }
       
   139 
       
   140         inline void setExpression(const Expression::Ptr &expr)
       
   141         {
       
   142             m_expression = expr;
       
   143         }
       
   144 
       
   145         /**
       
   146          * @short Returns how many times this variable is used.
       
   147          */
       
   148         inline bool usedByMany() const
       
   149         {
       
   150             return references.count() > 1;
       
   151         }
       
   152 
       
   153         /**
       
   154          * @short Returns @c true if @p list contains @p lookup.
       
   155          */
       
   156         static bool contains(const VariableDeclaration::List &list,
       
   157                              const QXmlName &lookup);
       
   158 
       
   159         const QXmlName                  name;
       
   160         const VariableSlotID            slot;
       
   161         const Type                      type;
       
   162 
       
   163         /**
       
   164          * The declared type of the variable. What the value might be, depends
       
   165          * on the context which VariableDeclaration is used in. Note that
       
   166          * sequenceType is hence not in anyway obligated to the type of
       
   167          * expression().
       
   168          */
       
   169         const SequenceType::Ptr         sequenceType;
       
   170         VariableReference::List         references;
       
   171 
       
   172         /**
       
   173          * @short Whether a reference can rewrite itself to expression().
       
   174          *
       
   175          * The default value is @c true.
       
   176          */
       
   177         bool canSourceRewrite;
       
   178 
       
   179     private:
       
   180         Expression::Ptr                 m_expression;
       
   181         Q_DISABLE_COPY(VariableDeclaration)
       
   182     };
       
   183 
       
   184     /**
       
   185      * @short Formats @p var appropriately for display.
       
   186      *
       
   187      * @relates VariableDeclaration
       
   188      */
       
   189     static inline QString formatKeyword(const VariableDeclaration::Ptr &var,
       
   190                                         const NamePool::Ptr &np)
       
   191     {
       
   192         Q_ASSERT(var);
       
   193         Q_ASSERT(np);
       
   194         return formatKeyword(np->displayName(var->name));
       
   195     }
       
   196 
       
   197 }
       
   198 
       
   199 QT_END_NAMESPACE
       
   200 
       
   201 QT_END_HEADER
       
   202 
       
   203 #endif