fix: check 'jack_free_description' function pointer before use (fixes #6)

Signed-off-by: Christopher Arndt <[email protected]>

Author: SpotlightKid

jacklib/api.py

@@ -1663,7 +1663,8 @@ def uuid_unparse(uuid, encoding=ENCODING):
 
 
 def free_description(description, free_description_itself=0):
-    jlib.jack_free_description(description, free_description_itself)
+    if jlib.jack_free_description:
+        jlib.jack_free_description(description, free_description_itself)
 
 
 def _decode_property(prop, encoding=ENCODING):
@@ -1707,7 +1708,7 @@ def get_all_properties(encoding=ENCODING):
                     for p_idx in range(description.property_cnt)
                 ]
 
-            jlib.jack_free_description(description, 0)
+            free_description(description, 0)
 
     free(descriptions)
     return results
@@ -1722,7 +1723,7 @@ def get_properties(subject, encoding=ENCODING):
         for p_idx in range(description.property_cnt):
             results.append(_decode_property(description.properties[p_idx], encoding))
 
-    jlib.jack_free_description(byref(description), 0)
+    free_description(byref(description), 0)
     return results