define subscribe error term

Author: yuki-uchida

moqt-server/src/modules/message_handlers/control_message/handlers/subscribe_handler.rs

@@ -39,18 +39,19 @@ pub(crate) async fn subscribe_handler(
 
     let downstream_subscribe_id = subscribe_message.subscribe_id();
     let downstream_session_id = client.id();
-    if !pubsub_relation_manager_repository
+
+    if pubsub_relation_manager_repository
         .is_downstream_subscribe_id_unique(downstream_subscribe_id, downstream_session_id)
         .await?
-        || !pubsub_relation_manager_repository
-            .is_downstream_subscribe_id_less_than_max(
-                downstream_subscribe_id,
-                downstream_session_id,
-            )
-            .await?
     {
-        // TODO: return TerminationErrorCode
-        bail!("TooManySubscribers");
+        bail!("DuplicateSubscribeID");
+    }
+
+    if pubsub_relation_manager_repository
+        .is_downstream_subscribe_id_less_than_max(downstream_subscribe_id, downstream_session_id)
+        .await?
+    {
+        bail!("SubscribeIDExceedsMaximum");
     }
 
     let downstream_track_alias = subscribe_message.track_alias();