--- /dev/null
+/////////////////////////////////////////////////////////////////////////////
+// Name: wx/tracker.h
+// Purpose: Support class for object lifetime tracking (wxWeakRef<T>)
+// Author: Arne Steinarson
+// Created: 2007-12-28
+// RCS-ID: $Id:$
+// Copyright: (c) 2007 Arne Steinarson
+// Licence: wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_TRACKER_H_
+#define _WX_TRACKER_H_
+
+// This structure represents an object tracker and is stored in a linked list
+// in the tracked object. It is only used in one of its derived forms.
+struct wxTrackerNode
+{
+ wxTrackerNode() : m_next(NULL) { }
+ virtual ~wxTrackerNode() { }
+
+ virtual void OnObjectDestroy() = 0;
+
+ // This is to tell the difference between different tracker node types.
+ // It's a replacement of dynamic_cast<> for this class since dynamic_cast
+ // may be disabled (and we don't have wxDynamicCast since wxTrackerNode
+ // is not derived wxObject).
+ enum wxTrackerNodeType { WeakRef, EventConnectionRef };
+
+ virtual wxTrackerNodeType GetType() = 0;
+
+protected:
+ wxTrackerNode *m_next;
+
+ friend class wxTrackableBase; // For list access
+ friend class wxEvtHandler; // For list access
+};
+
+
+// Add-on base class for a trackable object.
+struct wxTrackableBase
+{
+ wxTrackableBase() : m_first(NULL) { }
+
+ ~wxTrackableBase()
+ {
+ // Notify all registered refs
+
+ // OnObjectDestroy has to remove the item from the link chain
+ while ( m_first )
+ {
+ wxTrackerNode *first = m_first;
+ first->OnObjectDestroy();
+ RemoveNode(first);
+ }
+ }
+
+ void AddNode(wxTrackerNode *node)
+ {
+ node->m_next = m_first;
+ m_first = node;
+ }
+
+ void RemoveNode(wxTrackerNode *node)
+ {
+ for ( wxTrackerNode **pn = &m_first; *pn; pn = &(*pn)->m_next )
+ {
+ if ( *pn == node )
+ {
+ *pn = node->m_next;
+ return;
+ }
+ }
+
+ wxFAIL_MSG( "node should be present" );
+ }
+
+ wxTrackerNode *GetFirst() { return m_first; }
+
+protected:
+ wxTrackerNode *m_first;
+};
+
+// The difference to wxTrackableBase is that this class adds
+// a VTable to enable dynamic_cast query for wxTrackable.
+struct wxTrackable : wxTrackableBase
+{
+ virtual ~wxTrackable() { }
+};
+
+
+// Helper to decide if an object has a base class or not
+// (strictly speaking, this test succeeds if a type is convertible
+// to another type in some way.)
+template <class T, class B>
+struct wxHasBase
+{
+ static char Match(B *pb);
+ static int Match(...);
+
+ enum { value = sizeof(Match((T*)NULL)) == sizeof(char) };
+};
+
+// A structure to cast to wxTrackableBase, using either static_cast<> or
+// dynamic_cast<>.
+template <class T, bool is_static>
+struct wxTrackableCaster;
+
+template <class T>
+struct wxTrackableCaster<T, true>
+{
+ static wxTrackableBase* Cast(T* pt)
+ {
+ return static_cast<wxTrackableBase *>(pt);
+ }
+};
+
+#ifdef HAVE_DYNAMIC_CAST
+
+template <class T>
+struct wxTrackableCaster<T, false>
+{
+ static wxTrackableBase *Cast(T* pt)
+ {
+ return dynamic_cast<wxTrackableBase *>(pt);
+ }
+};
+
+#else // !HAVE_DYNAMIC_CAST
+
+template <class T>
+struct wxTrackableCaster<T, false>
+{
+ static wxTrackableBase *Cast(T* pt) { return NULL; }
+};
+
+#endif // HAVE_DYNAMIC_CAST/!HAVE_DYNAMIC_CAST
+
+#endif // _WX_TRACKER_H_
+
--- /dev/null
+/////////////////////////////////////////////////////////////////////////////
+// Name: wx/weakref.h
+// Purpose: wxWeakRef - Generic weak references for wxWidgets
+// Author: Arne Steinarson
+// Created: 2007-12-27
+// RCS-ID: $Id:$
+// Copyright: (c) 2007 Arne Steinarson
+// Licence: wxWindows licence
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef _WX_WEAKREF_H_
+#define _WX_WEAKREF_H_
+
+#include <wx/tracker.h>
+
+// A weak reference to an object of type T, where T has type wxTrackable
+// as one of its base classes (in a static or dynamic sense).
+template<class T>
+class wxWeakRef : public wxTrackerNode
+{
+public:
+ wxWeakRef(T *pobj = NULL) : m_pobj(NULL) { Assign(pobj); }
+
+ virtual ~wxWeakRef() { Assign(NULL); }
+
+ // Smart pointer functions
+ operator T*(){ return m_pobj; }
+ T* operator->(){ return m_pobj; }
+ T* operator=(T *pobj)
+ {
+ Assign(pobj);
+ return m_pobj;
+ }
+
+ virtual void OnObjectDestroy()
+ {
+ // Tracked object itself removes us from list of trackers
+ wxASSERT( m_pobj );
+ m_pobj = NULL;
+ }
+
+ virtual wxTrackerNodeType GetType() { return WeakRef; }
+
+protected:
+ wxTrackableBase *GetTrackable(T *pobj)
+ {
+ // this uses static_cast if possible or dynamic_cast otherwise
+ return wxTrackableCaster<T, wxHasBase<T, wxTrackableBase>::value>
+ ::Cast(pobj);
+ }
+
+ void Assign(T* pobj)
+ {
+ if ( m_pobj == pobj )
+ return;
+
+ // First release old object if any
+ if ( m_pobj )
+ {
+ // Remove ourselves from object tracker list
+ GetTrackable(m_pobj)->RemoveNode(this);
+ m_pobj = NULL;
+ }
+
+ // Now set new trackable object
+ if ( pobj )
+ {
+ wxTrackableBase * const pt = GetTrackable(pobj);
+ wxCHECK_RET( pt, "type must derive from wxTrackableBase" );
+
+ pt->AddNode(this);
+ m_pobj = pobj;
+ }
+ }
+
+ T *m_pobj;
+};
+
+// Provide some basic types of weak references
+class WXDLLIMPEXP_FWD_BASE wxObject;
+class WXDLLIMPEXP_FWD_BASE wxEvtHandler;
+class WXDLLIMPEXP_FWD_CORE wxWindow;
+
+typedef wxWeakRef<wxObject> wxObjectRef;
+typedef wxWeakRef<wxEvtHandler> wxEvtHandlerRef;
+typedef wxWeakRef<wxWindow> wxWindowRef;
+
+#endif // _WX_WEAKREF_H_
+
projects / wxWidgets.git / commitdiff
