Changed the destructor protocol to prevent "refcount leakage". The

reference counts of extension classes are increased when instances are
created.  Prior to this change, the class ref counts were only
decreased by subclass destructors.  Base class destructors followed
the Python protocol and didn't DECREF thier classes (types).  (Python
type ref counts have nothing to do with instance life times, since
Python types are static, unlike extension classes, which may be
dynamic.)

This caused the ref counts of instantiatable base classes to grow,
which looked like a memory leak.

Now, the destructor protocol calls for base class destructors to
DECREF the class in addition to deallocating the object.  The subclass
destructor *only* DECREFs the class if it has to deallocate the object
because there was no base class destructor.

This also fixed an logic ordering problem that caused some dynamically
created classes to be destroyed while they were still needed.

lib/Components/ExtensionClass/ExtensionClass.c

@@ -33,7 +33,7 @@
   USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
 
-  $Id: ExtensionClass.c,v 1.34 1999/05/24 13:47:02 jim Exp $
+  $Id: ExtensionClass.c,v 1.35 1999/06/10 20:04:40 jim Exp $
 
   If you have questions regarding this software,
   contact:
@@ -54,7 +54,7 @@ static char ExtensionClass_module_documentation[] =
 "  - They provide access to unbound methods,\n"
 "  - They can be called to create instances.\n"
 "\n"
-"$Id: ExtensionClass.c,v 1.34 1999/05/24 13:47:02 jim Exp $\n"
+"$Id: ExtensionClass.c,v 1.35 1999/06/10 20:04:40 jim Exp $\n"
 ;
 
 #include <stdio.h>
@@ -1583,7 +1583,7 @@ CCL_dealloc(PyExtensionClass *self)
       
       Py_DECREF(self->bases);
     }
-  Py_XDECREF(self->ob_type);
+  if (((PyExtensionClass*)self->ob_type) != self) Py_DECREF(self->ob_type);
   PyMem_DEL(self);
 }
   
@@ -2948,6 +2948,7 @@ static void
 subclass_dealloc(PyObject *self)
 {
   PyObject *m, *t, *v, *tb;
+  int base_dealloced;
 
 #ifdef TRACE_DEALLOC
   fprintf(stderr,"Deallocating a %s\n", self->ob_type->tp_name);
@@ -2979,10 +2980,22 @@ subclass_dealloc(PyObject *self)
     }
   
   if (HasInstDict(self)) Py_XDECREF(INSTANCE_DICT(self));
-  Py_DECREF(self->ob_type);
 
-  UNLESS(dealloc_base(self,(PyExtensionClass*)self->ob_type))
-    PyMem_DEL(self);
+  /* See if there was a dealloc handler in a (C) base class.
+     If there was, then it deallocates the object and we
+     get a true value back. 
+
+     Note that if there *is* a base class dealloc, then
+     *it* should decref the class.
+  */
+  base_dealloced=dealloc_base(self,(PyExtensionClass*)self->ob_type);
+
+  /* We only */
+  UNLESS(base_dealloced) 
+    {
+      Py_DECREF(self->ob_type);
+      PyMem_DEL(self);
+    }
 
   PyErr_Restore(t,v,tb);
 }
@@ -3403,7 +3416,7 @@ void
 initExtensionClass()
 {
   PyObject *m, *d;
-  char *rev="$Revision: 1.34 $";
+  char *rev="$Revision: 1.35 $";
   PURE_MIXIN_CLASS(Base, "Minimalbase class for Extension Classes", NULL);
 
   PMethodType.ob_type=&PyType_Type;

lib/Components/ExtensionClass/src/ExtensionClass.c

@@ -33,7 +33,7 @@
   USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   DAMAGE.
 
-  $Id: ExtensionClass.c,v 1.34 1999/05/24 13:47:02 jim Exp $
+  $Id: ExtensionClass.c,v 1.35 1999/06/10 20:04:40 jim Exp $
 
   If you have questions regarding this software,
   contact:
@@ -54,7 +54,7 @@ static char ExtensionClass_module_documentation[] =
 "  - They provide access to unbound methods,\n"
 "  - They can be called to create instances.\n"
 "\n"
-"$Id: ExtensionClass.c,v 1.34 1999/05/24 13:47:02 jim Exp $\n"
+"$Id: ExtensionClass.c,v 1.35 1999/06/10 20:04:40 jim Exp $\n"
 ;
 
 #include <stdio.h>
@@ -1583,7 +1583,7 @@ CCL_dealloc(PyExtensionClass *self)
       
       Py_DECREF(self->bases);
     }
-  Py_XDECREF(self->ob_type);
+  if (((PyExtensionClass*)self->ob_type) != self) Py_DECREF(self->ob_type);
   PyMem_DEL(self);
 }
   
@@ -2948,6 +2948,7 @@ static void
 subclass_dealloc(PyObject *self)
 {
   PyObject *m, *t, *v, *tb;
+  int base_dealloced;
 
 #ifdef TRACE_DEALLOC
   fprintf(stderr,"Deallocating a %s\n", self->ob_type->tp_name);
@@ -2979,10 +2980,22 @@ subclass_dealloc(PyObject *self)
     }
   
   if (HasInstDict(self)) Py_XDECREF(INSTANCE_DICT(self));
-  Py_DECREF(self->ob_type);
 
-  UNLESS(dealloc_base(self,(PyExtensionClass*)self->ob_type))
-    PyMem_DEL(self);
+  /* See if there was a dealloc handler in a (C) base class.
+     If there was, then it deallocates the object and we
+     get a true value back. 
+
+     Note that if there *is* a base class dealloc, then
+     *it* should decref the class.
+  */
+  base_dealloced=dealloc_base(self,(PyExtensionClass*)self->ob_type);
+
+  /* We only */
+  UNLESS(base_dealloced) 
+    {
+      Py_DECREF(self->ob_type);
+      PyMem_DEL(self);
+    }
 
   PyErr_Restore(t,v,tb);
 }
@@ -3403,7 +3416,7 @@ void
 initExtensionClass()
 {
   PyObject *m, *d;
-  char *rev="$Revision: 1.34 $";
+  char *rev="$Revision: 1.35 $";
   PURE_MIXIN_CLASS(Base, "Minimalbase class for Extension Classes", NULL);
 
   PMethodType.ob_type=&PyType_Type;