add environment variable to enable profile stats collection

it makes a difference on the flame graph but not a noticeable one in
top

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 { })
@@ -150,38 +158,38 @@ label.readout {
 
 (local cq (cqueues.new))
 
-(fn road-width-for [line offset]
-  (+ (or offset 0)
-     (case (?. line :tags :highway)
-       :motorway 18
-       :trunk 17
-       :primary 16
-       :secondary 14
-       :cycleway 4
-       :footway 4
-       other 12)))
-
-(fn cairo-road-path [g [[sx sy] & points] bounds width]
-  (g:save)
-  (g:set_line_width width)
-  (g:move_to (* tile-size (- sx bounds.min.x))
-             (* tile-size (- sy bounds.min.y)))
-  (each [_ [x y] (ipairs points)]
-    (let [x1 (* tile-size (- x bounds.min.x))
-          y1 (* tile-size (- y bounds.min.y))]
-      (g:line_to x1 y1)))
-  (g:stroke)
-  (g:restore))
+(fn road-width-for [line]
+  (case (?. line :tags :highway)
+    :motorway 18
+    :trunk 17
+    :primary 16
+    :secondary 14
+    :cycleway 4
+    :footway 4
+    other 12))
 
+(fn cairo-road-path [g [[sx sy] & points] bounds]
+  (let [min bounds.min
+        { : line_to } g]
+    (g:move_to (* tile-size (- sx min.x))
+               (* tile-size (- sy min.y)))
+    (each [_ [x y] (ipairs points)]
+      (let [x1 (* tile-size (- x min.x))
+            y1 (* tile-size (- y min.y))]
+        (line_to g x1 y1)))))
 
 (fn cairo-roads [g lines bounds]
-  (let [road-width 14]
-    (g:set_source_rgb 0 0 0)
-    (each [_ line (pairs lines)]
-      (cairo-road-path g line.points bounds (road-width-for line)))
-    (g:set_source_rgb 1 1 1)
-    (each [_ line (pairs lines)]
-      (cairo-road-path g line.points bounds (road-width-for line -2)))))
+  (g:set_source_rgb 0 0 0)
+  (each [_ line (pairs lines)]
+    (g:set_line_width (road-width-for line))
+    (cairo-road-path g line.points bounds )
+    (g:stroke))
+  (g:set_source_rgb 1 1 1)
+  (each [_ line (pairs lines)]
+    (g:set_line_width (- (road-width-for line) 2))
+    (cairo-road-path g line.points bounds)
+    (g:stroke)))
+
 
 (var map-surface nil)
 
@@ -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)

pkgs/maps/shell.nix

@@ -16,13 +16,34 @@ let
       };
     };
   fennel-ls = pkgs.fennel-ls.override { inherit (package) lua luaPackages; };
+  luaProfiler =
+    let
+      inherit (pkgs) stdenv cmake;
+      inherit (package) lua;
+    in stdenv.mkDerivation {
+      name = "LuaProfiler";
+      src = fetchFromGitHub {
+        owner = "Patrick08T";
+        repo = "LuaProfiler";
+        rev = "abb989337f6f46b820c9d2eb1e1d339e8f6f3760";
+        hash = "sha256-43kwZCZZmWD5ens1qCzD7LTg/jKMfcb9Vw/DBiN2sSo=";
+      };
+      buildInputs = [ lua ];
+      installPhase = ''
+        mkdir -p "$out/lib/lua/${lua.luaversion}"
+        echo cp /build/source/bin/release/libluaperf.so "$out/lib/lua/${lua.luaversion}"
+        cp /build/source/bin/release/libluaperf.so "$out/lib/lua/${lua.luaversion}"
+      '';
+      nativeBuildInputs = [ cmake ];
+    };
 in
 package.overrideAttrs(o: {
-  nativeBuildInputs = [ fennel-ls ] ++ o.nativeBuildInputs;
+  nativeBuildInputs = [ fennel-ls luaProfiler flamegraph  ] ++ o.nativeBuildInputs;
   shellHook = ''
     mkdir -p bin
     ( cd bin && ln -sf `type -p fennel-ls` `type -p fennel` . )
-    export LUA_CPATH=$(lua -e "print(package.cpath)")
+    export LUA_CPATH=$(lua -e "print(package.cpath)")\;${luaProfiler}/lib/lua/${package.lua.luaversion}/\?.so
     export LUA_PATH=$(lua -e "print(package.path)")\;$RXI_JSON/share/lua/5.3/?.lua
+
   '';
 })