// Name: wx/tracker.h
// Purpose: Support class for object lifetime tracking (wxWeakRef<T>)
// Author: Arne Steinarson
-// Created: 2007-12-28
-// RCS-ID: $Id$
+// Created: 28 Dec 07
// Copyright: (c) 2007 Arne Steinarson
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_TRACKER_H_
#define _WX_TRACKER_H_
+#include "wx/defs.h"
-// This structure represents an object tracker and is stored in a linked list
+class wxEventConnectionRef;
+
+// This class 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_nxt(0) { }
+class WXDLLIMPEXP_BASE wxTrackerNode
+{
+public:
+ wxTrackerNode() : m_nxt(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:
+
+ virtual void OnObjectDestroy() = 0;
+
+ virtual wxEventConnectionRef *ToEventConnection() { return NULL; }
+
+private:
wxTrackerNode *m_nxt;
- friend class wxTrackableBase; // For list access
+
+ friend class wxTrackable; // For list access
friend class wxEvtHandler; // For list access
};
-
// Add-on base class for a trackable object.
-struct wxTrackableBase {
- wxTrackableBase() : m_first(0) { }
- ~wxTrackableBase()
- {
- // Notify all registered refs
-
- wxTrackerNode *first;
- while( m_first )
- {
- first = m_first;
- first->OnObjectDestroy( );
- RemoveNode(first);
- }
- }
-
- void AddNode( wxTrackerNode *prn )
+class WXDLLIMPEXP_BASE wxTrackable
+{
+public:
+ void AddNode(wxTrackerNode *prn)
{
prn->m_nxt = m_first;
m_first = prn;
}
- void RemoveNode( wxTrackerNode *prn )
+
+ void RemoveNode(wxTrackerNode *prn)
{
- for( wxTrackerNode **pprn=&m_first; *pprn; pprn=&(*pprn)->m_nxt )
+ for ( wxTrackerNode **pprn = &m_first; *pprn; pprn = &(*pprn)->m_nxt )
{
- if( *pprn==prn )
+ if ( *pprn == prn )
{
*pprn = prn->m_nxt;
return;
}
}
- // Not found, an error.
- wxASSERT( false );
+
+ wxFAIL_MSG( "removing invalid tracker node" );
}
-
- wxTrackerNode* GetFirst( ){ return m_first; }
- // If trying to copy this object, then do not copy its ref list.
- wxTrackableBase& operator = (const wxTrackableBase& WXUNUSED(other)) { return *this; }
-
-protected:
- wxTrackerNode *m_first;
-};
+ wxTrackerNode *GetFirst() const { return m_first; }
+protected:
+ // this class is only supposed to be used as a base class but never be
+ // created nor destroyed directly so all ctors and dtor are protected
-// The difference to wxTrackableBase is that this class adds
-// a VTable to enable dynamic_cast query for wxTrackable.
-struct wxTrackable : public wxTrackableBase
-{
- virtual ~wxTrackable(){ }
-};
+ wxTrackable() : m_first(NULL) { }
+ // copy ctor and assignment operator intentionally do not copy m_first: the
+ // objects which track the original trackable shouldn't track the new copy
+ wxTrackable(const wxTrackable& WXUNUSED(other)) : m_first(NULL) { }
+ wxTrackable& operator=(const wxTrackable& WXUNUSED(other)) { return *this; }
-// 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)) };
-};
+ // dtor is not virtual: this class is not supposed to be used
+ // polymorphically and adding a virtual table to it would add unwanted
+ // overhead
+ ~wxTrackable()
+ {
+ // Notify all registered refs
+ while ( m_first )
+ {
+ wxTrackerNode * const first = m_first;
+ m_first = first->m_nxt;
+ first->OnObjectDestroy();
+ }
+ }
-// VC++ before 7.1 does not have partial template specialization
-#ifdef __VISUALC__
- #if __VISUALC__ < 1310
- #define HAVE_NO_PARTIAL_SPECIALIZATION
- #endif
-#endif
-
-#if defined(HAVE_DYNAMIC_CAST) && !defined(HAVE_NO_PARTIAL_SPECIALIZATION)
- // 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); }
- };
-
- template <class T>
- struct wxTrackableCaster<T,false> {
- static wxTrackableBase* Cast(T* pt){ return dynamic_cast<wxTrackableBase*>(pt); }
- };
-#else
- #if defined(HAVE_DYNAMIC_CAST)
- // If we have dynamic_cast, default to that. For gcc, dynamic_cast<> does the job
- // of both the dynamic and the static case. It could be that all compilers do it
- // that way, rendering the specialization code above rednundant.
- template <class T,bool is_static>
- struct wxTrackableCaster {
- static wxTrackableBase* Cast(T* pt){ return dynamic_cast<wxTrackableBase*>(pt); }
- };
- #else
- // No dynamic_cast<> is available.
- // We use static_cast<>, that gives support for wxEvtHandler and wxWindow references.
- // We don't get weak refs to other wxObject derived types.
- template <class T,bool is_static>
- struct wxTrackableCaster {
- static wxTrackableBase* Cast(T* pt){ return static_cast<wxTrackableBase*>(pt); }
- };
- #endif
-#endif
+ wxTrackerNode *m_first;
+};
#endif // _WX_TRACKER_H_
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