factor-lang: Improve application deployment

Build staging images ahead of time for re-use during application
deployment.

pkgs/development/compilers/factor-lang/mk-factor-application.nix

@@ -5,6 +5,7 @@
   makeBinaryWrapper,
   factor-lang,
   factor-no-gui,
+  staging-images,
   librsvg,
   gdk-pixbuf,
 }@initAttrs:
@@ -113,6 +114,9 @@ in
         vocabBaseName=$(basename "$vocabName")
         mkdir -p "$out/lib/factor" "$TMPDIR/.cache"
         export XDG_CACHE_HOME="$TMPDIR/.cache"
+        mkdir "$XDG_CACHE_HOME/factor"
+        cp -r "${staging-images}"/lib/factor/staging.* "$XDG_CACHE_HOME/factor"
+        chmod -R u+w "$XDG_CACHE_HOME/factor"
 
         # Deploy script writes the deploy path to to $PWD/deploy-path.txt
         factor "${deployScript}" "./$vocabName" "$out/lib/factor"

pkgs/development/compilers/factor-lang/staging.nix

@@ -0,0 +1,29 @@
+{
+  lib,
+  stdenv,
+  factor-unwrapped,
+}:
+stdenv.mkDerivation {
+  pname = "factor-staging-images";
+  inherit (factor-unwrapped) version meta;
+
+  dontUnpack = true;
+
+  preBuild = ''
+    # Factor uses XDG_CACHE_HOME for cache during compilation.
+    # We can't have that. So, set it to $TMPDIR/.cache
+    export XDG_CACHE_HOME=$TMPDIR/.cache
+    mkdir -p $XDG_CACHE_HOME
+  '';
+
+  buildPhase = ''
+    runHook preBuild
+    ${factor-unwrapped}/lib/factor/factor -script -e='USING: kernel system tools.deploy.backend ; "compiler" "hello-world" [ deploy-config config>profile make-staging-image ] bi@'
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    mkdir -p $out/lib/factor
+    cp -r $XDG_CACHE_HOME/factor/staging.* $out/lib/factor
+  '';
+}

pkgs/top-level/factor-packages.nix

@@ -32,6 +32,8 @@ let
         enableDefaults = false;
       };
 
+      staging-images = callPackage ../development/compilers/factor-lang/staging.nix { };
+
       # Vocabularies
       bresenham = callPackage ../development/factor-vocabs/bresenham { };