liminix/pkgs/pseudofile/default.nix

{ writeText, lib }:
let
  inherit (lib.attrsets) mapAttrsToList;
  visit =
    prefix: attrset:
    let
      qprint = msg: builtins.replaceStrings [ "\n" "=" "\"" "$" ] [ "=0A" "=3D" "=22" "=24" ] msg;
      l = mapAttrsToList (
        filename:
        {
          type ? "f",
          mode ? null,
          target ? null,
          contents ? null,
          file ? null,
          major ? null,
          minor ? null,
          uid ? 0,
          gid ? 0,
        }:
        let
          mode' = if mode != null then mode else (if type == "d" then "0755" else "0644");
          pathname = "${prefix}/${filename}";
          line = "${pathname} ${type} ${mode'} ${toString uid} ${toString gid}";
        in
        if type == "f" then
          "${line} echo -n \"${qprint file}\" |qprint -d"
        else if type == "d" then
          (visit pathname contents) + "\n" + line
        else if type == "c" then
          "${line} ${major} ${minor}"
        else if type == "b" then
          "${line} ${major} ${minor}"
        else if type == "s" then
          "${line} ${target}"
        else if type == "l" then
          "${pathname} l ${target}"
        else if type == "i" then
          "${line} f"
        else
          line
      ) attrset;
    in
    builtins.concatStringsSep "\n" l;
in
{
  write = filename: attrset: writeText filename (visit "" attrset);
  dir = contents: {
    type = "d";
    inherit contents;
  };
  symlink = target: {
    type = "s";
    inherit target;
  };
}