maps: read from gnss unix socket

pkgs/maps/main.fnl

@@ -1,9 +1,12 @@
 ; (local { : view } (require :fennel))
+(local { : fdopen } (require :posix.stdio))
 
 (local {
         : Gtk
         : OsmGpsMap
         : Gdk
+        : Gio
+        : GLib
         }
        (require :lgi))
 
@@ -60,6 +63,25 @@ label.readout {
     (: :add (readout "00:00"))
     (: :add (readout "25 km/h"))))
 
+(local gnss-socket
+       (let [addr (Gio.UnixSocketAddress {
+                                          :path "/var/run/gnss-share.sock"
+                                          })]
+         (: (Gio.SocketClient) :connect addr nil)))
+
+(fn read-gnss [socket]
+  (each [l #(socket:read "l")]
+    (print "gnss" l))
+  true)
+
+(let [sock (gnss-socket:get_socket)
+      fd (sock:get_fd)
+      events [ GLib.IOCondition.IN GLib.IOCondition.HUP]
+      channel (GLib.IOChannel.unix_new fd)
+      handle (fdopen fd :r)]
+  (GLib.io_add_watch channel 0 events #(read-gnss handle)))
+
+
 (window:add
  (doto (Gtk.Overlay {})
    (: :add (osm-widget))