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|
open Lwt.Syntax
open Lwt.Infix
open Lwt_react
open Stream
type step =
| Starting_stream
| Negotiating_feature of Feature.requirement * features
| Logged_in of features
type state =
| Disconnected
| Connecting of Portal.domain
(* TCP/WebSocket connected, not connected in XMPP-land *)
| Connected of Portal.t * step
(** An XMPP session. This type contains a signal representing the state of an XMPP
connection, and its update function. *)
type t = {
state : state signal;
update : state -> unit;
}
(** [create domain config] is a promise containing a session representing the portal
connected to the XMPP server located at [domain].
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 (config : config) : t Lwt.t =
let needs_restart = function
| Feature.Mechanisms _ | STARTTLS -> true
| _ -> false
and features_next_state = function
| feature :: rest -> Negotiating_feature (feature, rest)
(* No features returned by stream start. Connection is completed. *)
| [] -> Logged_in []
and eq s1 s2 = (* TODO: move this closer to the state type *)
match s1, s2 with
| Connected (_, step1), Connected (_, step2) -> step1 = step2
| _ -> s1 = s2
in
let state, update = S.create ~eq Disconnected in
let+ () = S.map_s
(function
| Connecting domain ->
let+ portal = Portal.connect domain
in update (Connected (portal, Starting_stream))
| Connected (portal, Starting_stream) ->
let+ features = Stream.start portal
in let next_state = features_next_state features
in update (Connected (portal, next_state))
| Connected (portal, Negotiating_feature (feature, features)) ->
let+ () = negotiate feature portal config
in let next_state = if needs_restart (Feature.unwrap feature)
then Starting_stream
else features_next_state features
in update (Connected (portal, next_state))
| _ -> Lwt.return_unit)
state >|= S.keep;
in { state; update }
|
