1 files changed, 165 insertions, 0 deletions
diff --git a/nixos/modules/services/x11/extra-layouts.nix b/nixos/modules/services/x11/extra-layouts.nix
new file mode 100644
index 00000000000..5523dd2bf02
--- /dev/null
+++ b/nixos/modules/services/x11/extra-layouts.nix
@@ -0,0 +1,165 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  layouts = config.services.xserver.extraLayouts;
+
+  layoutOpts = {
+    options = {
+      description = mkOption {
+        type = types.str;
+        description = "A short description of the layout.";
+      };
+
+      languages = mkOption {
+        type = types.listOf types.str;
+        description =
+        ''
+          A list of languages provided by the layout.
+          (Use ISO 639-2 codes, for example: "eng" for english)
+        '';
+      };
+
+      compatFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = ''
+          The path to the xkb compat file.
+          This file sets the compatibility state, used to preserve
+          compatibility with xkb-unaware programs.
+          It must contain a <literal>xkb_compat "name" { ... }</literal> block.
+        '';
+      };
+
+      geometryFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = ''
+          The path to the xkb geometry file.
+          This (completely optional) file describes the physical layout of
+          keyboard, which maybe be used by programs to depict it.
+          It must contain a <literal>xkb_geometry "name" { ... }</literal> block.
+        '';
+      };
+
+      keycodesFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = ''
+          The path to the xkb keycodes file.
+          This file specifies the range and the interpretation of the raw
+          keycodes sent by the keyboard.
+          It must contain a <literal>xkb_keycodes "name" { ... }</literal> block.
+        '';
+      };
+
+      symbolsFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = ''
+          The path to the xkb symbols file.
+          This is the most important file: it defines which symbol or action
+          maps to each key and must contain a
+          <literal>xkb_symbols "name" { ... }</literal> block.
+        '';
+      };
+
+      typesFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = ''
+          The path to the xkb types file.
+          This file specifies the key types that can be associated with
+          the various keyboard keys.
+          It must contain a <literal>xkb_types "name" { ... }</literal> block.
+        '';
+      };
+
+    };
+  };
+
+in
+
+{
+
+  ###### interface
+
+  options.services.xserver = {
+    extraLayouts = mkOption {
+      type = types.attrsOf (types.submodule layoutOpts);
+      default = {};
+      example = literalExample
+      ''
+        {
+          mine = {
+            description = "My custom xkb layout.";
+            languages = [ "eng" ];
+            symbolsFile = /path/to/my/layout;
+          };
+        }
+      '';
+      description = ''
+        Extra custom layouts that will be included in the xkb configuration.
+        Information on how to create a new layout can be found here:
+        <link xlink:href="https://www.x.org/releases/current/doc/xorg-docs/input/XKB-Enhancing.html#Defining_New_Layouts"></link>.
+        For more examples see
+        <link xlink:href="https://wiki.archlinux.org/index.php/X_KeyBoard_extension#Basic_examples"></link>
+      '';
+    };
+
+  };
+
+  ###### implementation
+
+  config = mkIf (layouts != { }) {
+
+    # We don't override xkeyboard_config directly to
+    # reduce the amount of packages to be recompiled.
+    # Only the following packages are necessary to set
+    # a custom layout anyway:
+    nixpkgs.overlays = lib.singleton (self: super: {
+
+      xkb_patched = self.xorg.xkeyboardconfig_custom {
+        layouts = config.services.xserver.extraLayouts;
+      };
+
+      xorg = super.xorg // {
+        xorgserver = super.xorg.xorgserver.overrideAttrs (old: {
+          configureFlags = old.configureFlags ++ [
+            "--with-xkb-bin-directory=${self.xorg.xkbcomp}/bin"
+            "--with-xkb-path=${self.xkb_patched}/share/X11/xkb"
+          ];
+        });
+
+        setxkbmap = super.xorg.setxkbmap.overrideAttrs (old: {
+          postInstall =
+            ''
+              mkdir -p $out/share
+              ln -sfn ${self.xkb_patched}/etc/X11 $out/share/X11
+            '';
+        });
+
+        xkbcomp = super.xorg.xkbcomp.overrideAttrs (old: {
+          configureFlags = "--with-xkb-config-root=${self.xkb_patched}/share/X11/xkb";
+        });
+
+      };
+
+      ckbcomp = super.ckbcomp.override {
+        xkeyboard_config = self.xkb_patched;
+      };
+
+      xkbvalidate = super.xkbvalidate.override {
+        libxkbcommon = self.libxkbcommon.override {
+          xkeyboard_config = self.xkb_patched;
+        };
+      };
+
+    });
+
+    services.xserver.xkbDir = "${pkgs.xkb_patched}/etc/X11/xkb";
+
+  };
+
+}