nix-helpers: e00c9c7c266898f68b57d52bea95d19095a4517c

     1: # Takes a directory path, returns any immediate children in that directory which
     2: # are themselves directories, and contain a file with the given name
     3: # ('default.nix' by default). Result is an attrset where names are the
     4: # subdirectory names, e.g. "subdir", and values are full paths to the contained
     5: # file, e.g. "${dir}/subdir/default.nix".
     6: #
     7: # Note that this is used to bootstrap nix-helpers, so it should work standalone.
     8: { }:
     9: 
    10: { dir, filename ? "default.nix" }:
    11: with rec {
    12:   inherit (builtins) attrNames filter getAttr hasAttr listToAttrs readDir;
    13: 
    14:   subdirs = filter hasFile (attrNames entries);
    15: 
    16:   entries = readDir dir;
    17: 
    18:   hasFile = name:
    19:     (getAttr name entries == "directory")
    20:     && (hasAttr filename (readDir (dir + "/${name}")));
    21: 
    22:   output = name: {
    23:     inherit name;
    24:     value = dir + "/${name}/${filename}";
    25:   };
    26: 
    27: };
    28: listToAttrs (map output subdirs)