metaobject.h

   1 /*
   2   metaobject.h
   3
   4   This file is part of GammaRay, the Qt application inspection and
   5   manipulation tool.
   6
   7   Copyright (C) 2011 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com
   8   Author: Volker Krause <volker.krause@kdab.com>
   9
  10   This program is free software; you can redistribute it and/or modify
  11   it under the terms of the GNU General Public License as published by
  12   the Free Software Foundation, either version 2 of the License, or
  13   (at your option) any later version.
  14
  15   This program is distributed in the hope that it will be useful,
  16   but WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18   GNU General Public License for more details.
  19
  20   You should have received a copy of the GNU General Public License
  21   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #ifndef GAMMARAY_METAOBJECT_H
  25 #define GAMMARAY_METAOBJECT_H
  26
  27 #include "metaproperty.h"
  28
  29 #include <QVector>
  30
  31 namespace GammaRay {
  32
  33 /** Compile-time introspection adaptor for non-QObject classes. */
  34 class MetaObject
  35 {
  36   public:
  37     MetaObject();
  38     virtual ~MetaObject();
  39
  40     /**
  41      * Returns the amount of properties available in this class (including base classes).
  42      */
  43     int propertyCount() const;
  44
  45     /**
  46      * Returns the property adaptor for index @p index.
  47      */
  48     MetaProperty *propertyAt(int index) const;
  49
  50     /** Add a base class meta object. */
  51     void addBaseClass(MetaObject *baseClass);
  52
  53     /** Add a property for this class. This transfers ownership. */
  54     void addProperty(MetaProperty *property);
  55
  56     /// Returns the name of the class represented by this object.
  57     QString className() const;
  58
  59     /** Casts a void pointer for an instance of this type to one appropriate
  60      * for use with the property at index @p index.
  61      * Make sure to use this when dealing with multi-inheritance.
  62      */
  63     void *castForPropertyAt(void *object, int index) const;
  64
  65   protected:
  66     /** Casts down to base class @p baseClassIndex.
  67      * This is important when traversing multi-inheritance trees.
  68      */
  69     virtual void *castToBaseClass(void *object, int baseClassIndex) const = 0;
  70
  71   protected:
  72     QVector<MetaObject*> m_baseClasses;
  73
  74   private:
  75     friend class MetaObjectRepository;
  76     void setClassName(const QString &className);
  77
  78   private:
  79     QVector<MetaProperty*> m_properties;
  80     QString m_className;
  81 };
  82
  83 /** Template implementation of MetaObject. */
  84 template <typename T, typename Base1 = void, typename Base2 = void, typename Base3 = void>
  85 class MetaObjectImpl : public MetaObject
  86 {
  87   public:
  88     void *castToBaseClass(void *object, int baseClassIndex) const
  89     {
  90       Q_ASSERT(baseClassIndex >= 0 && baseClassIndex < m_baseClasses.size());
  91       switch (baseClassIndex) {
  92       case 0:
  93         return static_cast<Base1*>(static_cast<T*>(object));
  94       case 1:
  95         return static_cast<Base2*>(static_cast<T*>(object));
  96       case 2:
  97         return static_cast<Base3*>(static_cast<T*>(object));
  98       }
  99       Q_ASSERT(!"WTF!?");
 100       return 0;
 101     }
 102 };
 103
 104 }
 105
 106 #endif // GAMMARAY_METAOBJECT_H