From cc83d8444b61554a6c89549284dd37956b4aff41 Mon Sep 17 00:00:00 2001
From: Vincent Bernardoff <vb@luminar.eu.org>
Date: Mon, 10 Oct 2016 15:37:01 +0200
Subject: [PATCH] add a safe mode for workers

---
 src/utils/lwt_utils.ml  | 5 +++--
 src/utils/lwt_utils.mli | 1 +
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/utils/lwt_utils.ml b/src/utils/lwt_utils.ml
index b2fcf5e15..cee2b3f7b 100644
--- a/src/utils/lwt_utils.ml
+++ b/src/utils/lwt_utils.ml
@@ -111,11 +111,12 @@ let queue () : ('a -> unit) * (unit -> 'a list Lwt.t) =
   queue, wait
 
 (* A worker launcher, takes a cancel callback to call upon *)
-let worker name ~run ~cancel =
+let worker ?(safe=false) name ~run ~cancel =
   let stop = LC.create () in
   let fail e =
     log_error "%s worker failed with %s" name (Printexc.to_string e) ;
-    cancel () >>= fun () -> Lwt.fail e
+    cancel () >>= fun () ->
+    if safe then Lwt.return_unit else Lwt.fail e
   in
   let waiter = LC.wait stop in
   log_info "%s worker started" name ;
diff --git a/src/utils/lwt_utils.mli b/src/utils/lwt_utils.mli
index 7f42580b7..b3ddc40fa 100644
--- a/src/utils/lwt_utils.mli
+++ b/src/utils/lwt_utils.mli
@@ -15,6 +15,7 @@ val canceler : unit ->
   ((unit -> unit Lwt.t) -> unit)
 
 val worker:
+  ?safe:bool ->
   string ->
   run:(unit -> unit Lwt.t) ->
   cancel:(unit -> unit Lwt.t) ->