/////////////////////////////////////////////////////////////////////////////
// Name: weakref.h
-// Purpose: interface of wxWeakRefDynamic<T>
+// Purpose: interface of wxWeakRefDynamic<T>, wxWeakRef<T>
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
-/**
+/**
wxWeakRefDynamic<T> is a template class for weak references that is used in
the same way as wxWeakRef<T>. The only difference is that wxWeakRefDynamic
- defaults to using @c dynamic_cast for establishing the object
- reference (while wxWeakRef defaults to @c static_cast).
+ defaults to using @c dynamic_cast for establishing the object reference
+ (while wxWeakRef defaults to @c static_cast).
So, wxWeakRef will detect a type mismatch during compile time and will
have a little better run-time performance. The role of wxWeakRefDynamic
is to handle objects which derived type one does not know.
- @note wxWeakRef<T> selects an implementation based on the static type
- of T. If T does not have wxTrackable statically, it defaults to to a mixed-
- mode operation, where it uses @c dynamic_cast as the last measure (if
- available from the compiler and enabled when building wxWidgets).
+ @note wxWeakRef<T> selects an implementation based on the static type of T.
+ If T does not have wxTrackable statically, it defaults to to a mixed-
+ mode operation, where it uses @c dynamic_cast as the last measure
+ (if available from the compiler and enabled when building wxWidgets).
For general cases, wxWeakRef<T> is the better choice.
- For API documentation, see: wxWeakRef<T>
+ For API documentation, see: wxWeakRef<T>.
- @library{wxcore}
- @category{FIXME}
+ @tparam T
+ The type to which the smart pointer points to.
+
+ @nolibrary
+ @category{smartpointers}
*/
template<typename T>
class wxWeakRefDynamic<T>
/**
-
- wxWeakRef is a template class for weak references to wxWidgets objects,
- such as wxEvtHandler, wxWindow and
- wxObject. A weak reference behaves much like an ordinary
- pointer, but when the object pointed is destroyed, the weak reference is
- automatically reset to a @NULL pointer.
+ wxWeakRef<T> is a template class for weak references to wxWidgets objects,
+ such as wxEvtHandler, wxWindow and wxObject.
+ A weak reference behaves much like an ordinary pointer, but when the object
+ pointed is destroyed, the weak reference is automatically reset to a @NULL pointer.
wxWeakRef<T> can be used whenever one must keep a pointer to an object
that one does not directly own, and that may be destroyed before the object
wxWeakRef<T> is a small object and the mechanism behind it is fast
(@b O(1)). So the overall cost of using it is small.
- Example
-
+ Example:
+
@code
wxWindow *wnd = new wxWindow( parent, wxID_ANY, "wxWindow" );
- wxWeakRef<wxWindow> wr = wnd;
+ wxWeakRef<wxWindow> wr = wnd;
wxWindowRef wr2 = wnd; // Same as above, but using a typedef
// Do things with window
wnd->Show( true );
- // Weak ref is used like an ordinary pointer
+ // Weak ref is used like an ordinary pointer
wr->Show( false );
- wnd->Destroy();
+ wnd->Destroy();
// Now the weak ref has been reset, so we don't risk accessing
// a dangling pointer:
wxASSERT( wr==NULL );
@endcode
- wxWeakRef<T> works for any objects that are derived from wxTrackable. By default,
- wxEvtHandler and wxWindow derive from wxTrackable. However, wxObject does not, so
- types like wxFont and wxColour are not trackable. The example below shows how to
- create a wxObject derived class that is trackable:
+ wxWeakRef<T> works for any objects that are derived from wxTrackable.
+ By default, wxEvtHandler and wxWindow derive from wxTrackable.
+ However, wxObject does not, so types like wxFont and wxColour are not
+ trackable. The example below shows how to create a wxObject derived class
+ that is trackable:
@code
class wxMyTrackableObject : public wxObject, public wxTrackable
- {
- // ... other members here
- };
+ {
+ // ... other members here
+ };
@endcode
The following types of weak references are predefined:
typedef wxWeakRef<wxWindow> wxWindowRef;
@endcode
+ @tparam T
+ The type to which the smart pointer points to.
- @library{wxbase}
- @category{FIXME}
+ @nolibrary
+ @category{smartpointers}
@see wxSharedPtr<T>, wxScopedPtr<T>
*/
template<typename T>
-class wxWeakRef<T>
+class wxWeakRef<T> : public wxTrackerNode
{
public:
+ /// Type of the element stored by this reference.
+ typedef T element_type;
+
/**
Constructor. The weak reference is initialized to @e pobj.
*/
Copy constructor.
*/
wxWeakRef(const wxWeakRef<T>& wr);
-
+
/**
Destructor.
*/
- ~wxWeakRef();
+ virtual ~wxWeakRef();
/**
Called when the tracked object is destroyed. Be default sets
- internal pointer to @NULL. You need to call this method if
- you override it.
+ internal pointer to @NULL.
+ You need to call this method if you override it.
*/
virtual void OnObjectDestroy();
T* operator =(wxWeakRef<T>& wr);
/**
- Implicit conversion to T*. Returns pointer to the tracked
- object or @NULL.
+ Implicit conversion to T*.
+ Returns pointer to the tracked object or @NULL.
*/
T* operator*() const;
/**
- Returns a reference to the tracked object. If the internal pointer is @NULL
- this method will cause an assert in debug mode.
+ Returns a reference to the tracked object.
+ If the internal pointer is @NULL this method will cause an assert in debug mode.
*/
- T operator*() const;
+ T& operator*() const;
/**
- Smart pointer member access. Returns a pointer to the
- tracked object. If the internal pointer is @NULL this
- method will cause an assert in debug mode.
+ Smart pointer member access.
+ Returns a pointer to the tracked object.
+ If the internal pointer is @NULL this method will cause an assert in debug mode.
*/
T* operator-();
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