NixOS · Jan 23, 2020 · Feb 17, 2020 · Feb 17, 2020 · Feb 18, 2020 · Feb 18, 2020
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
@@ -66,11 +66,11 @@
 /doc/languages-frameworks/python.section.md     @FRidh
 
 # Haskell
-/pkgs/development/compilers/ghc                       @basvandijk @cdepillabout
-/pkgs/development/haskell-modules                     @basvandijk @cdepillabout @infinisil
-/pkgs/development/haskell-modules/default.nix         @basvandijk @cdepillabout
-/pkgs/development/haskell-modules/generic-builder.nix @basvandijk @cdepillabout
-/pkgs/development/haskell-modules/hoogle.nix          @basvandijk @cdepillabout
+/pkgs/development/compilers/ghc                       @cdepillabout
+/pkgs/development/haskell-modules		      @cdepillabout @infinisil
+/pkgs/development/haskell-modules/default.nix	      @cdepillabout
+/pkgs/development/haskell-modules/generic-builder.nix @cdepillabout
+/pkgs/development/haskell-modules/hoogle.nix	      @cdepillabout
 
 # Perl
 /pkgs/development/interpreters/perl @volth

diff --git a/nixos/doc/manual/configuration/x-windows.xml b/nixos/doc/manual/configuration/x-windows.xml
@@ -160,6 +160,38 @@
    package into your system environment. It should work for all Qt 5 library
    versions.
   </para>
+  <para>
+   With help of
+   <option>
+    <link linkend="opt-gtk.enable">
+     gtk
+    </link>
+   </option>
+   and
+   <option>
+    <link linkend="opt-qt.enable">
+     qt
+    </link>
+   </option>
+   modules you can declaratively set system-wide themes settings.
+<programlisting>
+  gtk.enable = true;
+  gtk.theme = {
+    name = "Adwaita-dark";
+    package = pkgs.gnome-themes-extra;
+  };
+  gtk.iconTheme = {
+    name = "Adwaita";
+    package = pkgs.gnome3.adwaita-icon-theme;
+  };
+  qt.enable = true;
+  qt.platformTheme = "gtk3";
+  qt.style = {
+    name = "adwaita-dark";
+    package = pkgs.adwaita-qt;
+  };
+</programlisting>
+  </para>
  </simplesect>
  <simplesect xml:id="custom-xkb-layouts">
   <title>Custom XKB layouts</title>

diff --git a/nixos/modules/config/gtk/gtk.nix b/nixos/modules/config/gtk/gtk.nix
@@ -0,0 +1,160 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.gtk;
+  gtk2 = cfg.enable && cfg.gtk2;
+
+  toGtk2File = key: value:
+    let
+      value' =
+        if isBool value then (if value then "true" else "false")
+        else if isString value then "\"${value}\""
+        else toString value;
+    in
+      "${key} = ${value'}";
+  toGtk3File = generators.toINI {
+    mkKeyValue = key: value:
+      let
+        value' =
+          if isBool value then (if value then "true" else "false")
+          else toString value;
+      in
+        "${key}=${value'}";
+  };
+
+  settings =
+    optionalAttrs (cfg.font != null)
+      { gtk-font-name = cfg.font.name; }
+    //
+    optionalAttrs (cfg.theme != null)
+      { gtk-theme-name = cfg.theme.name; }
+    //
+    optionalAttrs (cfg.iconTheme != null)
+      { gtk-icon-theme-name = cfg.iconTheme.name; }
+    //
+    optionalAttrs (cfg.cursorTheme != null)
+      { gtk-cursor-theme-name = cfg.cursorTheme.name; };
+
+  fontType = types.submodule {
+    options = {
+      package = mkOption {
+        internal = true;
+        type = types.nullOr types.package;
+        default = null;
+      };
+      name = mkOption {
+        internal = true;
+        type = types.str;
+      };
+    };
+  };
+  themeType = types.submodule {
+    options = {
+      package = mkOption {
+        internal = true;
+        type = types.nullOr types.package;
+        default = null;
+      };
+      name = mkOption {
+        internal = true;
+        type = types.str;
+      };
+    };
+  };
+
+  optionalPackage = opt:
+    optional (opt != null && opt.package != null) opt.package;
+in
+{
+  options = {
+    gtk = {
+      enable = mkEnableOption "Gtk theming configuration";
+
+      gtk2 = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Whether to enable theming for obsolete GTK2 engine.
+        '';
+      };
+
+      font = mkOption {
+        type = types.nullOr fontType;
+        default = null;
+        example = literalExample ''
+          {
+            name = "Cantarell 11";
+            package = pkgs.cantarell-fonts;
+          };
+        '';
+        description = ''
+          The font to use in GTK+ applications.
+        '';
+      };
+
+      iconTheme = mkOption {
+        type = types.nullOr themeType;
+        default = null;
+        example = literalExample ''
+          {
+            name = "Adwaita";
+            package = pkgs.gnome3.adwaita-icon-theme;
+          };
+        '';
+        description = "The icon theme to use.";
+      };
+
+      cursorTheme = mkOption {
+        type = types.nullOr themeType;
+        default = null;
+        example = literalExample ''
+          {
+            name = "Adwaita";
+            package = pkgs.gnome3.adwaita-icon-theme;
+          };
+        '';
+        description = "The cursor theme to use.";
+      };
+
+      theme = mkOption {
+        type = types.nullOr themeType;
+        default = null;
+        example = literalExample ''
+          {
+            name = "Adwaita";
+            package = pkgs.gnome-themes-extra;
+          };
+        '';
+        description = "The GTK+ theme to use.";
+      };
+    };
+  };
+
+  config = mkMerge [
+
+    (mkIf gtk2 {
+      environment.etc."xdg/gtk-2.0/gtkrc".text =
+        concatStringsSep "\n" (
+          mapAttrsToList toGtk2File settings
+        );
+    })
+
+    (mkIf cfg.enable {
+      environment.systemPackages =
+        optionalPackage cfg.font
+        ++ optionalPackage cfg.theme
+        ++ optionalPackage cfg.iconTheme
+        ++ optionalPackage cfg.cursorTheme;
+
+      environment.etc."xdg/gtk-3.0/settings.ini".text =
+        toGtk3File { Settings = settings; };
+
+      # TODO: support Wayland/XSettings
+      # once https://github.com/NixOS/nixpkgs/issues/54150 is fixed
+    })
+  ];
+
+  meta.maintainers = [ maintainers.gnidorah ];
+}