Fix the bug Jeremy was experiencing: both the close() and the

dealloc() functions contained code to free/DECREF the buffer
(there were differences between I and O objects but the logic bug was
the same).  Fixed this be setting the buffer pointer to NULL and
testing for that.  (This also makes it safe to call close() more than
once.)

XXX Worry: what if you try to read() or write() once the thing is
closed?

Modules/cStringIO.c

@@ -314,7 +314,9 @@ static char O_close__doc__[] = "close(): explicitly release resources held.";
 
 static PyObject *
 O_close(Oobject *self, PyObject *args) {
-  free(self->buf);
+  if (self->buf != NULL)
+    free(self->buf);
+  self->buf = NULL;
 
   self->pos = self->string_size = self->buf_size = 0;
   self->closed = 1;
@@ -392,7 +394,8 @@ static struct PyMethodDef O_methods[] = {
 
 static void
 O_dealloc(Oobject *self) {
-  free(self->buf);
+  if (self->buf != NULL)
+    free(self->buf);
   PyMem_DEL(self);
 }
 
@@ -475,7 +478,8 @@ newOobject(int  size) {
 
 static PyObject *
 I_close(Iobject *self, PyObject *args) {
-  Py_DECREF(self->pbuf);
+  Py_XDECREF(self->pbuf);
+  self->pbuf = NULL;
 
   self->pos = self->string_size = 0;
   self->closed = 1;
@@ -499,7 +503,7 @@ static struct PyMethodDef I_methods[] = {
 
 static void
 I_dealloc(Iobject *self) {
-  Py_DECREF(self->pbuf);
+  Py_XDECREF(self->pbuf);
   PyMem_DEL(self);
 }
 
@@ -627,6 +631,17 @@ initcStringIO() {
 /******************************************************************************
 
   $Log$
+  Revision 2.7  1997/09/03 00:09:26  guido
+  Fix the bug Jeremy was experiencing: both the close() and the
+  dealloc() functions contained code to free/DECREF the buffer
+  (there were differences between I and O objects but the logic bug was
+  the same).  Fixed this be setting the buffer pointer to NULL and
+  testing for that.  (This also makes it safe to call close() more than
+  once.)
+
+  XXX Worry: what if you try to read() or write() once the thing is
+  closed?
+
   Revision 2.6  1997/08/13 03:14:41  guido
   cPickle release 0.3 from Jim Fulton