Ts/db reference counting for match-iterators in python (rhbz#241751)

Adds additional refcounting to the python level ts/db object to avoid
anonymous ts/db from getting deleted while still iterating over it.

python/rpmdb-py.c

@@ -126,7 +126,7 @@ rpmdb_Match (rpmdbObject * s, PyObject * args, PyObject * kwds)
 	return NULL;
     }
 
-    return rpmmi_Wrap( rpmdbInitIterator(s->db, tag, key, len) );
+    return rpmmi_Wrap( rpmdbInitIterator(s->db, tag, key, len), (PyObject *)s);
 }
 
 /**

python/rpmmi-py.c

@@ -199,6 +199,7 @@ static void rpmmi_dealloc(/*@only@*/ /*@null@*/ rpmmiObject * s)
 {
     if (s) {
 	s->mi = rpmdbFreeIterator(s->mi);
+	Py_DECREF(s->ref);
 	PyObject_Del(s);
     }
 }
@@ -271,7 +272,7 @@ PyTypeObject rpmmi_Type = {
 };
 /*@=fullinitblock@*/
 
-rpmmiObject * rpmmi_Wrap(rpmdbMatchIterator mi)
+rpmmiObject * rpmmi_Wrap(rpmdbMatchIterator mi, PyObject *s)
 {
     rpmmiObject * mio = (rpmmiObject *) PyObject_New(rpmmiObject, &rpmmi_Type);
 
@@ -280,6 +281,8 @@ rpmmiObject * rpmmi_Wrap(rpmdbMatchIterator mi)
         return NULL;
     }
     mio->mi = mi;
+    mio->ref = s;
+    Py_INCREF(mio->ref);
     return mio;
 }
 

python/rpmmi-py.h

@@ -14,6 +14,7 @@ typedef struct rpmmiObject_s rpmmiObject;
 struct rpmmiObject_s {
     PyObject_HEAD
     PyObject *md_dict;		/*!< to look like PyModuleObject */
+    PyObject *ref;		/* for db/ts refcounting */
     rpmdbMatchIterator mi;
 } ;
 
@@ -21,7 +22,7 @@ struct rpmmiObject_s {
 extern PyTypeObject rpmmi_Type;
 
 /*@null@*/
-rpmmiObject * rpmmi_Wrap(rpmdbMatchIterator mi)
+rpmmiObject * rpmmi_Wrap(rpmdbMatchIterator mi, PyObject *s)
 	/*@*/;
 
 #endif

python/rpmts-py.c

@@ -1397,7 +1397,7 @@ fprintf(stderr, "*** rpmts_Match(%p) ts %p\n", s, s->ts);
 	}
     }
 
-    return rpmmi_Wrap( rpmtsInitIterator(s->ts, tag, key, len) );
+    return rpmmi_Wrap( rpmtsInitIterator(s->ts, tag, key, len), (PyObject*)s);
 }
 
 /** \ingroup py_c