metaproperty.h

   1 /*
   2   metaproperty.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_METAPROPERTY_H
  25 #define GAMMARAY_METAPROPERTY_H
  26
  27 #include <QString>
  28 #include <QVariant>
  29
  30 namespace GammaRay {
  31
  32 class MetaObject;
  33
  34 /** Introspectable adaptor to non-QObject properties. */
  35 class MetaProperty
  36 {
  37   public:
  38     MetaProperty();
  39     virtual ~MetaProperty();
  40
  41     /// User-readable name of that property
  42     virtual QString name() const = 0;
  43
  44     /// Current value of the property for object @p object.
  45     virtual QVariant value(void *object) const = 0;
  46
  47     /// Returns @c true if this property is read-only.
  48     virtual bool isReadOnly() const = 0;
  49
  50     /// Allows changing the property value, assuming it's not read-only, for the instance @p object.
  51     virtual void setValue(void *object, const QVariant &value) = 0;
  52
  53     /// Returns the name of the data type of this property.
  54     virtual QString typeName() const = 0;
  55
  56     /// Returns the class this property belongs to.
  57     MetaObject *metaObject() const;
  58
  59   private:
  60     friend class MetaObject;
  61     void setMetaObject(MetaObject *om);
  62
  63     MetaObject *m_class;
  64 };
  65
  66 /** Template-ed implementation of MetaProperty. */
  67 template <typename Class, typename ValueType, typename SetterArgType = ValueType>
  68 class MetaPropertyImpl : public MetaProperty
  69 {
  70   public:
  71     inline MetaPropertyImpl(
  72       const QString &name,
  73       ValueType (Class::*getter)() const, void (Class::*setter)(SetterArgType) = 0)
  74       : m_name(name), m_getter(getter), m_setter(setter)
  75     {
  76     }
  77
  78     inline QString name() const
  79     {
  80       return m_name;
  81     }
  82
  83     inline bool isReadOnly() const
  84     {
  85       return m_setter == 0 ;
  86     }
  87
  88     inline QVariant value(void *object) const
  89     {
  90       Q_ASSERT(object);
  91       return value(static_cast<Class*>(object));
  92     }
  93
  94     inline void setValue(void *object, const QVariant &value)
  95     {
  96       setValue(static_cast<Class*>(object), value);
  97     }
  98
  99   private:
 100     inline QVariant value(Class *object) const
 101     {
 102       Q_ASSERT(object);
 103       const ValueType v = (object->*(m_getter))();
 104       return QVariant::fromValue(v);
 105     }
 106
 107     inline void setValue(Class *object, const QVariant &value)
 108     {
 109       if (isReadOnly()) {
 110         return;
 111       }
 112       (object->*(m_setter))(value.value<ValueType>());
 113     }
 114
 115     inline QString typeName() const
 116     {
 117       return QMetaType::typeName(qMetaTypeId<ValueType>()) ;
 118     }
 119
 120   private:
 121     QString m_name;
 122     ValueType (Class::*m_getter)() const;
 123     void (Class::*m_setter)(SetterArgType);
 124 };
 125
 126 }
 127
 128 #endif