(* Js_of_ocaml library
 * http://www.ocsigen.org/js_of_ocaml/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, with linking exception;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *)

open Js_of_ocaml

exception Rejected of Promise.error

let to_lwt (p : 'a Promise.t) : 'a Lwt.t =
  let t, w = Lwt.task () in
  let _ : unit Promise.t =
    Promise.then_
      ~on_error:(fun e ->
        Lwt.wakeup_later_exn w (Rejected e);
        Promise.resolve ())
      (fun x ->
        Lwt.wakeup_later w x;
        Promise.resolve ())
      p
  in
  t

let of_lwt (t : 'a Lwt.t) : 'a Promise.t =
  Promise.make (fun ~resolve ~reject ->
      Lwt.on_any t resolve (fun exn -> reject (Promise.error_of_exn exn)))
