This class is just a typedef to wxRefCounter and is used by wxObject.
- Derive classes from this to store your own data in wxObject derived
+ Derive classes from this to store your own data in wxObject-derived
classes. When retrieving information from a wxObject's reference data,
you will need to cast to your own derived class.
-
+
Below is an example illustrating how to store reference counted
data in a class derived from wxObject including copy-on-write
semantics.
m_refData = new MyCarRefData();
M_CARDATA->m_price = price;
}
-
+
wxObjectRefData *MyCar::CreateRefData() const
{
return new MyCarRefData;
{
if (m_refData == car.m_refData)
return true;
- if (!m_refData || !car.m_refData)
+ if (!m_refData || !car.m_refData)
return false;
// here we use the MyCarRefData::operator==() function.
}
@endcode
-
+
@library{wxbase}
@category{rtti}
interface and a counter. wxRefCounter can be easily used together
with wxObjectDataPtr<T> to ensure that no calls to wxRefCounter::DecRef()
are missed - thus avoiding memory leaks.
-
+
wxObjectRefData is a typedef to wxRefCounter and is used as the
- built-in reference counted storage for wxObject derive classes.
+ built-in reference counted storage for wxObject-derived classes.
@library{wxbase}
@category{rtti}
@library{wxbase}
@category{rtti}
- @see wxClassInfo, @ref overview_debugging, @ref overview_refcount,
+ @see wxClassInfo, @ref overview_debugging, @ref overview_refcount,
wxObjectDataRef, wxObjectDataPtr<T>
*/
class wxObject
Ensure that this object's data is not shared with any other object.
If we have no data, it is created using CreateRefData();
- if we have shared data (i.e. data with a reference count greater than 1),
+ if we have shared data (i.e. data with a reference count greater than 1),
it is copied using CloneRefData(); otherwise nothing is done (the data
is already present and is not shared by other object instances).
-
+
If you use this function you should make sure that you override the
CreateRefData() and CloneRefData() functions in your class otherwise
an assertion will fail at runtime.
/**
Creates a new instance of the wxObjectRefData-derived class specific to
this object and returns it.
-
+
This is usually implemented as a one-line call:
@code
wxObjectRefData *MyObject::CreateRefData() const
/**
Creates a new instance of the wxObjectRefData-derived class specific to
this object and initializes it copying @a data.
-
+
This is usually implemented as a one-line call:
@code
wxObjectRefData *MyObject::CloneRefData(const wxObjectRefData *data) const
public:
MyCarRefData( int price = 0 ) : m_price(price) { }
MyCarRefData( const MyCarRefData& data ) : m_price(data.m_price) { }
-
+
void SetPrice( int price ) { m_price = price; }
int GetPrice() const { return m_price; }
-
+
protected:
int m_price;
};
if (m_data.get() == other.m_data.get())
return true; // this instance and the 'other' one share the
// same MyCarRefData data...
-
+
return (m_data.GetPrice() == other.m_data.GetPrice());
}
// make sure changes to this class do not affect other instances
// currently sharing our same refcounted data:
UnShare();
-
+
m_data->SetPrice( price );
}