\section{\class{wxObjectDataPtr<T>}}\label{wxobjectdataptr}
-This is helper template class to avoid memleaks because of missing calls
-to \helpref{wxObjectRefData::DecRef}{wxobjectrefdatadecref}.
+This is helper template class primarily written to avoid memory
+leaks because of missing calls to \helpref{wxObjectRefData::DecRef}{wxobjectrefdatadecref}.
-Despite the name this template can actually be used for any
-class implementing the reference counting interface and it
-does not use or depend on wxObject.
+Despite the name this template can actually be used as a
+smart pointer for any class implementing the reference
+counting interface which only consists of the two methods
+{\bf T::IncRef()} and {\bf T::DecRef()}.
+
+The difference to \helpref{wxSharedPtr}{wxsharedptr} is that
+wxObjectDataPtr relies on the reference counting to be in
+the class pointed to where as wxSharedPtr implements the
+reference counting itself.
\wxheading{See also}
\helpref{wxObjectRefData}{wxobjectrefdata},
\helpref{Reference counting}{trefcount}
+\helpref{wxSharedPtr}{wxsharedptr},
+\helpref{wxScopedPtr}{wxscopedptrtemplate},
+\helpref{wxWeakRef}{wxweakref}
+
+
\wxheading{Derived from}
No base class
\wxheading{Data structures}
-{\small \begin{verbatim}
-typedef T element\_type
-\end{verbatim}}
+{\small%
+\begin{verbatim}
+typedef T element_type
+\end{verbatim}
+}%
\wxheading{Example}
\begin{verbatim}
-// include file
-
class MyCarRefData: public wxObjectRefData
{
public:
m_price = data.m_price;
}
- bool operator == (const MyCarRefData& data) const
- {
- return m_price == data.m_price;
- }
-
void SetPrice( int price ) { m_price = price; }
int GetPrice() { return m_price; }
class MyCar
{
public:
- MyCar( int price );
- MyCar( const MyCar& data );
+ MyCar( int price ) : m_data( new MyCarRefData )
+ {
+ m_data->SetPrice( price );
+ }
+
+ MyCar& operator =( const MyCar& tocopy )
+ {
+ m_data = tocopy.m_data;
+ return *this;
+ }
- bool operator == ( const MyCar& car ) const;
- bool operator != (const MyCar& car) const { return !(*this == car); }
+ bool operator == ( const MyCar& other ) const
+ {
+ if (m_data.get() == other.m_data.get()) return true;
+ return (m_data->GetPrice() == other.m_data->GetPrice());
+ }
- void SetPrice( int price );
- int GetPrice() const;
+ void SetPrice( int price )
+ {
+ UnShare();
+ m_data->SetPrice( price );
+ }
+
+ int GetPrice() const
+ {
+ return m_data->GetPrice();
+ }
- wxObjectRefPtr<MyCarRefData> m_data;
+ wxObjectDataPtr<MyCarRefData> m_data;
protected:
- void UnShare();
-};
-
-
-// implementation
-
-MyCar::MyCar( int price )
-{
- m_data = new MyCarRefData;
- m_data.get()->SetPrice( price );
-}
-
-MyCar::MyCar( const MyCar& car )
-{
- m_data.reset( car.m_data.get() );
-}
-
-bool MyCar::operator == ( const MyCar& car ) const
-{
- if (m_data.get() == car.m_data.get()) return true;
-
- return (*m_data.get() == *car.m_data.get());
-}
-
-void MyCar::SetPrice( int price )
-{
- UnShare();
-
- m_data.get()->SetPrice( price );
-}
-
-int MyCar::GetPrice() const
-{
- return m_data.get()->GetPrice();
-}
-
-void MyCar::UnShare()
-{
- if (m_data.get()->GetCount() == 1)
- return;
+ void UnShare()
+ {
+ if (m_data->GetRefCount() == 1)
+ return;
- m_data.reset( new MyCarRefData( *m_data.get() ) );
-}
+ m_data.reset( new MyCarRefData( *m_data ) );
+ }
+};
\end{verbatim}
\func{wxEXPLICIT}{wxObjectDataPtr<T>}{\param{T* }{ptr = NULL}}
Constructor. {\it ptr} is a pointer to the reference
-counted object to which this class points.
+counted object to which this class points. If {\it ptr}
+is not NULL {\bf T::IncRef()} will be called on the
+object.
\func{}{wxObjectDataPtr<T>}{\param{const wxObjectDataPtr<T>\& }{tocopy}}
\func{}{\destruct{wxObjectDataPtr<T>}}{\void}
-Calls \helpref{DecRef}{wxobjectrefdatadecref} on the reference
-counted object to which this class points.
+Decreases the reference count of the object to which this
+class points.
+
+\membersection{wxObjectDataPtr<T>::operator unspecified\_bool\_type}\label{wxobjectdataptroperatorbool}
+
+\constfunc{}{operator unspecified\_bool\_type}{\void}
+
+Conversion to a boolean expression (in a variant which is not
+convertable to anything but a boolean expression). If this class
+contains a valid pointer it will return {\it true}, if it contains
+a NULL pointer it will return {\it false}.
+
+\membersection{wxObjectDataPtr<T>::operator*}\label{wxobjectdataptroperatorreft}
+
+\constfunc{T \&}{operator*}{\void}
+
+Returns a reference to the object. If the internal pointer is NULL
+this method will cause an assert in debug mode.
\membersection{wxObjectDataPtr<T>::operator->}\label{wxobjectdataptroperatorpointer}
\constfunc{T*}{operator->}{\void}
-Gets a pointer to the reference counted object to which
-this class points. Same as \helpref{get}{wxobjectdataptrget}.
+Returns a pointer to the reference counted object to which
+this class points. If this the internal pointer is NULL,
+this method will assert in debug mode.
\membersection{wxObjectDataPtr<T>::operator=}\label{wxobjectdataptroperatorassign}
\func{void}{reset}{\param{T* }{ptr}}
Reset this class to {\it ptr} which points to a reference
-counted object.
+counted object and calls {\bf T::DecRef()} on the previously
+owned object.
projects / wxWidgets.git / blobdiff