[ground_segment] represent unconfirmed settings with infinity

proposal to fix #1012:
- server: represent initial/unknown/unconfirmed settings with infinity
- page_settings: set label text to "?" upon commit and on update if value is "inf", also set label to "?"

sw/ground_segment/cockpit/page_settings.ml

@@ -36,10 +36,14 @@ object
     let (alt_a, alt_b) = Ocaml_tools.affine_transform auc in
     (float_of_string current_value#text -. alt_b) /. alt_a
   method update = fun s ->
-    if current_value#text <> s then begin
-      current_value#set_text s;
-      try set_default (float_of_string s) with Failure "float_of_string" -> ()
-    end
+    (* value of infinity (string "inf") means it is not yet confirmed, so display "?" *)
+    if s = "inf" then
+      current_value#set_text "?"
+    else
+      if current_value#text <> s then begin
+        current_value#set_text s;
+        try set_default (float_of_string s) with Failure "float_of_string" -> ()
+      end
 end
 
 let pipe_regexp = Str.regexp "|"
@@ -199,7 +203,8 @@ let one_setting = fun (i:int) (do_change:int -> float -> unit) packing dl_settin
   let _icon = GMisc.image ~stock:`APPLY ~packing:commit_but#add () in
   let callback = fun x ->
     prev_value := (try Some ((float_of_string current_value#text-.alt_b)/.alt_a) with _ -> None);
-    commit x
+    commit x;
+    current_value#set_text "?"
   in
   ignore (commit_but#connect#clicked ~callback);
   tooltips#set_tip commit_but#coerce ~text:"Commit";

sw/ground_segment/tmtc/aircraft.ml

@@ -217,7 +217,7 @@ let new_aircraft = fun id name fp airframe ->
     cam = { phi = 0.; theta = 0. ; target=(0.,0.)};
     fbw = { rc_status = "???"; rc_mode = "???"; rc_rate=0; pprz_mode_msgs_since_last_fbw_status_msg=0 };
     svinfo = svsinfo_init;
-    dl_setting_values = Array.create max_nb_dl_setting_values 42.;
+    dl_setting_values = Array.create max_nb_dl_setting_values infinity;
     nb_dl_setting_values = 0;
     horiz_mode = UnknownHorizMode;
     horizontal_mode = 0;

sw/ground_segment/tmtc/server.ml

@@ -677,7 +677,11 @@ let setting = fun logging _sender vs ->
              "ac_id", Pprz.String ac_id;
              "value", List.assoc "value" vs] in
   Dl_Pprz.message_send dl_id "SETTING" vs;
-  log logging ac_id "SETTING" vs
+  log logging ac_id "SETTING" vs;
+  (* mark the setting as not yet confirmed *)
+  let ac = Hashtbl.find aircrafts ac_id in
+  let idx = Pprz.int_of_value (List.assoc "index" vs) in
+  ac.dl_setting_values.(idx) <- infinity
 
 
 (** Got a GET_DL_SETTING, and send an GET_SETTING *)