add bcc api to outbox

lib/server/outbox.ml

@@ -3,12 +3,36 @@ open! Import
 type t = {
   stream : Irc.Msg.t Lwt_stream.t;
   push : Irc.Msg.t option -> unit;
+  mutable bcc : t Dllist.node option;
 }
 
 let make () =
   let stream, push = Lwt_stream.create () in
-  { stream; push }
+  { stream; push; bcc = None }
 
 let stream t = t.stream
 let send t msg = try t.push (Some msg) with Lwt_stream.Closed -> ()
 let close t = try t.push None with Lwt_stream.Closed -> ()
+
+type bcc = { recipients : t Dllist.t }
+
+let make_bcc () = {
+  recipients = Dllist.create ();
+}
+
+let excl obx =
+  Option.iter Dllist.remove obx.bcc;
+  obx.bcc <- None
+
+let incl bcc obx =
+  Option.iter Dllist.remove obx.bcc;
+  obx.bcc <- Some (Dllist.add_r obx bcc.recipients)
+
+let rec send_all bcc msg =
+  match Dllist.take_l bcc.recipients with
+  | obx ->
+    obx.bcc <- None;
+    send obx msg;
+    send_all bcc msg
+  | exception Dllist.Empty ->
+    ()