Add new api to vtkDebugLeaks to track vtk object lifetime

Change-Id: I5c45fbc337fc7c1fccdbef4c831624862f7cbfb9

Common/vtkDebugLeaks.cxx

@@ -305,6 +305,36 @@ void vtkDebugLeaks::DestructClass(const char*)
 }
 #endif
 
+//----------------------------------------------------------------------------
+void vtkDebugLeaks::SetDebugLeaksObserver(vtkDebugLeaksObserver* observer)
+{
+  vtkDebugLeaks::Observer = observer;
+}
+
+//----------------------------------------------------------------------------
+vtkDebugLeaksObserver* vtkDebugLeaks::GetDebugLeaksObserver()
+{
+  return vtkDebugLeaks::Observer;
+}
+
+//----------------------------------------------------------------------------
+void vtkDebugLeaks::ConstructingObject(vtkObjectBase* object)
+{
+  if (vtkDebugLeaks::Observer)
+    {
+    vtkDebugLeaks::Observer->ConstructingObject(object);
+    }
+}
+
+//----------------------------------------------------------------------------
+void vtkDebugLeaks::DestructingObject(vtkObjectBase* object)
+{
+  if (vtkDebugLeaks::Observer)
+    {
+    vtkDebugLeaks::Observer->DestructingObject(object);
+    }
+}
+
 //----------------------------------------------------------------------------
 int vtkDebugLeaks::PrintCurrentLeaks()
 {
@@ -413,10 +443,12 @@ void vtkDebugLeaks::ClassInitialize()
 
   // Default to error when leaks occur while running tests.
   vtkDebugLeaks::ExitError = 1;
+  vtkDebugLeaks::Observer = 0;
 #else
   vtkDebugLeaks::MemoryTable = 0;
   vtkDebugLeaks::CriticalSection = 0;
   vtkDebugLeaks::ExitError = 0;
+  vtkDebugLeaks::Observer = 0;
 #endif
 }
 
@@ -458,3 +490,5 @@ vtkSimpleCriticalSection* vtkDebugLeaks::CriticalSection;
 
 // Purposely not initialized.  ClassInitialize will handle it.
 int vtkDebugLeaks::ExitError;
+
+vtkDebugLeaksObserver* vtkDebugLeaks::Observer;

Common/vtkDebugLeaks.h

@@ -33,6 +33,7 @@
 
 class vtkDebugLeaksHashTable;
 class vtkSimpleCriticalSection;
+class vtkDebugLeaksObserver;
 
 class VTK_COMMON_EXPORT vtkDebugLeaks : public vtkObject
 {
@@ -64,6 +65,10 @@ public:
   // Default is on when VTK_DEBUG_LEAKS is on and off otherwise.
   static int GetExitError();
   static void SetExitError(int);
+  //BTX
+  static void SetDebugLeaksObserver(vtkDebugLeaksObserver* observer);
+  static vtkDebugLeaksObserver* GetDebugLeaksObserver();
+  //ETX
 
 protected:
   vtkDebugLeaks(){}; 
@@ -74,17 +79,34 @@ protected:
   static void ClassInitialize();
   static void ClassFinalize();
 
+  static void ConstructingObject(vtkObjectBase* object);
+  static void DestructingObject(vtkObjectBase* object);
+
   //BTX
   friend class vtkDebugLeaksManager;
+  friend class vtkObjectBase;
   //ETX
 
 private:
   static vtkDebugLeaksHashTable* MemoryTable;
   static vtkSimpleCriticalSection* CriticalSection;
+  static vtkDebugLeaksObserver* Observer;
   static int ExitError;
 
   vtkDebugLeaks(const vtkDebugLeaks&);  // Not implemented.
   void operator=(const vtkDebugLeaks&);  // Not implemented.
 };
 
+//BTX
+// This class defines callbacks for debugging tools. The callbacks are not for general use.
+// The objects passed as arguments to the callbacks are in partially constructed or destructed
+// state and accessing them may cause undefined behavior.
+class VTK_COMMON_EXPORT vtkDebugLeaksObserver {
+public:
+  virtual ~vtkDebugLeaksObserver() {};
+  virtual void ConstructingObject(vtkObjectBase*) = 0;
+  virtual void DestructingObject(vtkObjectBase*) = 0;
+};
+//ETX
+
 #endif // __vtkDebugLeaks_h

Common/vtkObjectBase.cxx

@@ -75,10 +75,17 @@ vtkObjectBase::vtkObjectBase()
 {
   this->ReferenceCount = 1;
   this->WeakPointers = 0;
+#ifdef VTK_DEBUG_LEAKS
+  vtkDebugLeaks::ConstructingObject(this);
+#endif
 }
 
 vtkObjectBase::~vtkObjectBase() 
 {
+#ifdef VTK_DEBUG_LEAKS
+  vtkDebugLeaks::DestructingObject(this);
+#endif
+
   // warn user if reference counting is on and the object is being referenced
   // by another object
   if ( this->ReferenceCount > 0)