def source
      @source ||= Dassets.config.sources.select do |source|
        @file_path =~ /^#{slash_path(source.path)}/
      end.last
    end
def source
      @source ||= Dassets.config.sources.select do |source|
        @file_path =~ /^#{slash_path(source.path)}/
      end.last
    end
get the last matching one (in the case two sources with the same path are
 configured) since we select the last matching source file (from the last
 configured source) in `find_by_digest_path` above.