nixpkgs/lib/filesystem.nix

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2017-03-04 11:15:23 -07:00
{ # locateDominatingFile : RegExp
# -> Path
# -> Nullable { path : Path;
# matches : [ MatchResults ];
# }
# Find the first directory containing a file matching 'pattern'
# upward from a given 'file'.
# Returns 'null' if no directories contain a file matching 'pattern'.
locateDominatingFile = pattern: file:
let go = path:
let files = builtins.attrNames (builtins.readDir path);
matches = builtins.filter (match: match != null)
(map (builtins.match pattern) files);
in
if builtins.length matches != 0
then { inherit path matches; }
else if path == /.
then null
else go (dirOf path);
parent = dirOf file;
isDir =
let base = baseNameOf file;
type = (builtins.readDir parent).${base} or null;
in file == /. || type == "directory";
in go (if isDir then file else parent);
}