Update fonts cache

[wedens]

When fonts.fonts = [ ]; list is modified in nixos, it causes fonts cache update. It'd be handy to have such option for fonts installed via home-manager so that you don't need to execute fc-cache -f manually.

[wedens]

Currently I use the following hack:

{config, pkgs, lib, ...}:

let
  cfg = config.fonts;
in

with lib;

{
  options = {
    fonts.fonts = mkOption {
      type = types.listOf types.package;
      default = [];
      example = literalExample "[ pkgs.dejavu_fonts ]";
      description = "List of fonts.";
    };
  };

  config = {
    home.packages = cfg.fonts;

    home.file."${config.xdg.cacheHome}/hm-fonts" = let
      getHash = drv: builtins.elemAt (builtins.match "${builtins.storeDir}/([a-z0-9]{32})-.*.drv" drv.drvPath) 0;
    in {
      text = concatMapStringsSep "\n" getHash cfg.fonts;
      onChange = ''
        echo "Caching fonts"
        $DRY_RUN_CMD fc-cache -f
      '';
    };
  };
}

It just saves a list of hashes of fonts derivations in a file and updates cache when the list changes.

@rycee Do you think it'll be useful to include it in some form in home-manager?

[Jomik]

This looks like a good idea to me 👍
Why fonts.fonts though? Maybe just a rootlevel fonts or do home.fonts?
I realize that NixOS uses fonts.fonts, i find the attribute name choice weird though.

[wedens]

Why fonts.fonts though? Maybe just a rootlevel fonts or do home.fonts?

There is already fonts.fontconfig, so it can't be just fonts. fonts.fonts is at least known from nixos.

[Jomik]

Oh, there is. Makes sense to follow NixOS then. I'd probably have chosen fonts.packages, but yours makes sense due to NixOS's choice 😃

[leotaku]

@rycee, @wedens are you still interested in having this added to home-manager?

[rycee]

If anybody is able to try it out then please have a look at #682, which I believe will resolve this issue. Note, you will have to add

fonts.fontconfig.enable = true;

to your configuration for it it take effect.