core (memory/sqlite): added before_uid filter to retrieve history before a message UID

sat/memory/sqlite.py

@@ -625,6 +625,9 @@ class SqliteStorage(object):
             if 'timestamp_start' in filters:
                 query_parts.append("AND timestamp>= ?")
                 values.append(float(filters['timestamp_start']))
+            if 'before_uid' in filters:
+                query_parts.append("AND history.rowid<(select rowid from history where uid=?)")
+                values.append(filters['before_uid'])
             if 'body' in filters:
                 # TODO: use REGEXP (function to be defined) instead of GLOB: https://www.sqlite.org/lang_expr.html
                 query_parts.append("AND message LIKE ?")