feat(sasl): add parse_features function

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/stream.ml b/lib/stream.ml
index 141e2a5..aa2e2e7 100644
--- a/lib/stream.ml
+++ b/lib/stream.ml
@@ -44,3 +44,29 @@ let start domain : Portal.t Lwt.t =
         (* TODO: check this is a good stanza *)
         let+ _ = get stream
         in stream, push
+
+let parse_features (el : Xml.element) : stream_features =
+  (** [parse_features el] is a [stream_features] record with all the features of the
+      [<stream:features>] stanza contained in [el]. *)
+  let open Xml in
+  let open Either in
+  let parse_mechanism_stanza = function
+    | Left {local_name = "mechanism"; children = [Right mechanism]; _} ->
+       Some (parse_auth_mechanism mechanism)
+    | _ -> None
+  in
+  let parse_feature (acc : stream_features) (feature : Xml.element) : stream_features =
+    let parse_mechanisms ch =
+      List.filter_map parse_mechanism_stanza ch
+    and parse_starttls = function
+      | [Left {local_name="required"; _}] -> `Required
+      | [] -> `Optional
+      | _ -> raise (InvalidStanza (element_to_string el))
+    in match feature.local_name with
+       | "mechanisms" -> {acc with sasl_mechanisms=parse_mechanisms feature.children}
+       | "starttls" ->  {acc with starttls=parse_starttls feature.children}
+       | _ -> {acc with unknown_features = feature :: acc.unknown_features}
+  in List.fold_left
+       parse_feature
+       {sasl_mechanisms=[]; starttls=`None; unknown_features=[]}
+       (List.filter_map find_left el.children)