# Index all files in `dir` recursively
	#
	# See `index_file`.
	fun index_dir(dir: String, auto_update: nullable Bool) do
		if not dir.to_path.is_dir then return
		for file in dir.files do
			var path = dir / file
			if path.to_path.is_dir then
				index_dir(path, false)
			else
				index_file(path, false)
			end
		end
		if auto_update != null and auto_update then update_index
	end