This patch fixes some segfaults caused by performing certain operations
 on a closed connection object.  The simplest example is:
    >>> import psycopg
    >>> conn = psycopg.connect('dbname=my_database')
    >>> conn.close()
    >>> conn.autocommit()
 The patch adds checks to the set_isolation_level(), autocommit() and
 serialize() methods to see if the connection is closed, and cleans
 up some dangling pointers during the connection close process to make
 future problems easier to debug.
    -- James Henstridge <james.henstridge@canonical.com> (2005-03-23)

--- psycopg-1.1.18/connection.c.orig	2005-03-23 18:02:14.763628280 +0800
+++ psycopg-1.1.18/connection.c	2005-03-23 18:04:04.849892624 +0800
@@ -265,12 +265,15 @@ _psyco_conn_close(connobject *self)
     
     Py_DECREF(self->cursors);
     Py_DECREF(self->avail_conn);
+    self->cursors = NULL;
+    self->avail_conn = NULL;
 
     /* orphan default cursor and destroy it (closing the last connection to the
        database) */
     Dprintf("_psyco_conn_close(): killing stdmanager\n");
     self->stdmanager->conn = NULL;
     Py_DECREF(self->stdmanager);
+    self->stdmanager = NULL;
 }
 
 static PyObject *
@@ -460,7 +463,9 @@ psyco_conn_set_isolation_level(connobjec
     if (!PyArg_ParseTuple(args, "l", &level)) {
         return NULL;
     }
-    
+
+    EXC_IFCLOSED(self);
+
     _psyco_conn_set_isolation_level(self, level);
     
     Py_INCREF(Py_None);
@@ -484,6 +489,9 @@ psyco_conn_autocommit(connobject *self, 
     }
 
     if (ac == 0) isolation_level = 2;
+
+    EXC_IFCLOSED(self);
+
     _psyco_conn_set_isolation_level(self, isolation_level);
 
     Py_INCREF(Py_None);
@@ -504,6 +512,8 @@ psyco_conn_serialize(connobject *self, P
         return NULL;
     }
 
+    EXC_IFCLOSED(self);
+
     /* save the value */
     self->serialize = (int)se;