nixos/xdg: add portal option

This factors the configuration out of the flatpak module.

nixos/modules/config/xdg/portal.nix

@@ -0,0 +1,38 @@
+{ config, pkgs ,lib ,... }:
+with lib;
+{
+  options.xdg.portal = {
+    enable =
+      mkEnableOption "<link xlink:href='https://github.com/flatpak/xdg-desktop-portal'>xdg desktop integration</link>"//{
+        default = true;
+      };
+
+    extraPortals = mkOption {
+      type = types.listOf types.package;
+      default = [];
+      description = ''
+        List of additional portals to add to path. Portals allow interaction
+        with system, like choosing files or taking screenshots. At minimum,
+        a desktop portal implementation should be listed. GNOME and KDE already
+        adds <package>xdg-desktop-portal-gtk</package>; and
+        <package>xdg-desktop-portal-kde</package> respectively. On other desktop
+        environments you probably want to add them yourself.
+      '';
+    };
+  };
+
+  config =
+    let
+      cfg = config.xdg.portal;
+      packages = [ pkgs.xdg-desktop-portal ] ++ cfg.extraPortals;
+
+    in mkIf cfg.enable {
+
+      services.dbus.packages  = packages;
+      systemd.packages = packages;
+      environment.variables = {
+        GTK_USE_PORTAL = "1";
+        XDG_DESKTOP_PORTAL_PATH = map (p: "${p}/share/xdg-desktop-portal/portals") cfg.extraPortals;
+      };
+    };
+}

nixos/modules/module-list.nix

@@ -11,6 +11,7 @@
   ./config/xdg/icons.nix
   ./config/xdg/menus.nix
   ./config/xdg/mime.nix
+  ./config/xdg/portal.nix
   ./config/appstream.nix
   ./config/xdg/sounds.nix
   ./config/gtk/gtk-icon-cache.nix

nixos/modules/rename.nix

@@ -19,6 +19,7 @@ with lib;
         let value = getAttrFromPath [ "services" "ddclient" "domain" ] config;
         in if value != "" then [ value ] else []))
     (mkRemovedOptionModule [ "services" "ddclient" "homeDir" ] "")
+    (mkRenamedOptionModule [ "services" "flatpak" "extraPortals" ] [ "xdg" "portal" "extraPortals" ])
     (mkRenamedOptionModule [ "services" "i2pd" "extIp" ] [ "services" "i2pd" "address" ])
     (mkRenamedOptionModule [ "services" "kubernetes" "apiserver" "admissionControl" ] [ "services" "kubernetes" "apiserver" "enableAdmissionPlugins" ])
     (mkRenamedOptionModule [ "services" "kubernetes" "apiserver" "address" ] ["services" "kubernetes" "apiserver" "bindAddress"])

nixos/modules/services/desktops/flatpak.nix

@@ -15,38 +15,22 @@ in {
   options = {
     services.flatpak = {
       enable = mkEnableOption "flatpak";
-
-      extraPortals = mkOption {
-        type = types.listOf types.package;
-        default = [];
-        description = ''
-          List of additional portals to add to path. Portals allow interaction
-          with system, like choosing files or taking screenshots. At minimum,
-          a desktop portal implementation should be listed. GNOME already
-          adds <package>xdg-desktop-portal-gtk</package>; for KDE, there
-          is <package>xdg-desktop-portal-kde</package>. Other desktop
-          environments will probably want to do the same.
-        '';
-      };
     };
   };
 
 
   ###### implementation
   config = mkIf cfg.enable {
+
     environment.systemPackages = [ pkgs.flatpak ];
 
-    services.dbus.packages = [ pkgs.flatpak pkgs.xdg-desktop-portal ] ++ cfg.extraPortals;
+    services.dbus.packages = [ pkgs.flatpak ];
 
-    systemd.packages = [ pkgs.flatpak pkgs.xdg-desktop-portal ] ++ cfg.extraPortals;
+    systemd.packages = [ pkgs.flatpak ];
 
     environment.profiles = [
       "$HOME/.local/share/flatpak/exports"
       "/var/lib/flatpak/exports"
     ];
-
-    environment.variables = {
-      XDG_DESKTOP_PORTAL_PATH = map (p: "${p}/share/xdg-desktop-portal/portals") cfg.extraPortals;
-    };
   };
 }

nixos/modules/services/x11/desktop-managers/gnome3.nix

@@ -154,7 +154,7 @@ in {
     services.hardware.bolt.enable = mkDefault true;
     services.xserver.libinput.enable = mkDefault true; # for controlling touchpad settings via gnome control center
     systemd.packages = [ pkgs.gnome3.vino ];
-    services.flatpak.extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
+    xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
 
     # If gnome3 is installed, build vim for gtk3 too.
     nixpkgs.config.vim.gui = "gtk3";

nixos/modules/services/x11/desktop-managers/plasma5.nix

@@ -224,6 +224,8 @@ in
       security.pam.services.sddm.enableKwallet = true;
       security.pam.services.slim.enableKwallet = true;
 
+      xdg.portal.extraPortals = [ pkgs.xdg-desktop-portal-kde ];
+
       # Update the start menu for each user that is currently logged in
       system.userActivationScripts.plasmaSetup = ''
         # The KDE icon cache is supposed to update itself