add environment variable to enable profile stats collection

pkgs/maps/main.fnl

@@ -8,6 +8,10 @@
 
 (import-macros { : define-tests : expect : expect= } :assert)
 
+(local profile
+       (and (os.getenv "IN_NIX_SHELL")
+            (require :libluaperf)))
+
 (macro with-timing [label & body]
   `(let [before# (ptime.clock_gettime ptime.CLOCK_PROCESS_CPUTIME_ID)
          ret# (table.pack (do ,body))]
@@ -58,13 +62,17 @@ label.readout {
      )
     (style_provider:load_from_data CSS)))
 
+(fn main-quit []
+  (when profile (profile:stop))
+  (Gtk.main_quit))
+
 (local window (Gtk.Window {
                            :title "Map"
                            :name "toplevel"
                            :default_width viewport-width
                            :default_height viewport-height
 
-                           :on_destroy Gtk.main_quit
+                           :on_destroy main-quit
                            }))
 
 (local state-widgets { })
@@ -453,6 +461,15 @@ label.readout {
    true)
  nil nil)
 
+(fn collect-profile []
+  (GLib.timeout_add
+   GLib.PRIORITY_DEFAULT
+   (* 60 1000) main-quit
+   nil nil)
+  (print "profiling for 60 seconds")
+  (profile.start 0))
+
+
 (window:add
  (doto (Gtk.Overlay {})
    (: :add (osm-widget))
@@ -463,4 +480,5 @@ label.readout {
 
 (window:show_all)
 (styles)
+(when (os.getenv "MAP_PROFILE") (collect-profile))
 (Gtk:main)