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|
open Lwt.Syntax
open Lwt.Infix
open Lwt_react
open Stream
type connection_step =
| Starting_stream
| Negotiating_feature of Feature.requirement * features
type state =
| Disconnected
| Opening_portal of string
| Connecting of Portal.t * connection_step
| Connected of Portal.t * features
(** [create domain config] is a promise containing a signal representing the portal
connected to the XMPP server located at [domain], and all its supported features.
When calling the function, the portal will try to connect to the provided domain.
Basically, it conforms to {{:
https://datatracker.ietf.org/doc/html/rfc6120#section-4.3 }}, and gets the Portal in
a "ready" state. *)
let create (domain : string) (config : config) : (state signal * (unit -> unit)) Lwt.t =
let needs_restart = function
| Feature.Mechanisms _ | STARTTLS -> true
| _ -> false
and features_next_state portal = function
| feature :: rest -> Connecting (portal, Negotiating_feature (feature, rest))
(* No features returned by stream start. Connection is completed. *)
| [] -> Connected (portal, [])
and eq s1 s2 = (* TODO: move this closer to the state type *)
match s1, s2 with
| Connecting (_, step1), Connecting (_, step2) -> step1 = step2
| Connected (_, f1), Connected (_, f2) -> f1 = f2
| _ -> s1 = s2
in
let state, update = S.create ~eq Disconnected in
let+ () = S.map_s
(function
| Opening_portal domain ->
let+ portal = Portal.connect domain
in update (Connecting (portal, Starting_stream))
| Connecting (portal, Starting_stream) ->
let+ features = Stream.start domain portal
in features_next_state portal features |> update
| Connecting (portal, Negotiating_feature (feature, features)) ->
let+ () = negotiate feature portal config
in let next_state = if needs_restart (Feature.unwrap feature)
then Connecting (portal, Starting_stream)
else features_next_state portal features
in update next_state
| _ -> Lwt.return_unit)
state >|= S.keep;
in state, fun () -> update (Opening_portal domain)
|
