erlang/elixir binary reference counters grouped by their id

brefc.ex

defmodule BinaryRefc do
  def run(take \\ 50, sort_by \\ :pids_count) do
    ref_procs =
      Enum.reduce(Process.list(), %{}, fn(pid, acc) ->
        [binary: refc_list] = Process.info(pid, [:binary])

        Enum.reduce(refc_list, acc, fn({ref, size, _count}, acc) ->
          acc
          |> Map.put_new({ref, size}, [])
          |> Map.update!({ref, size}, fn(list) -> [pid | list] end)
        end)
      end)

    ref_procs
    |> Enum.sort_by(sort_by_fn(sort_by), &>=/2)
    |> Enum.take(take)
    |> Enum.map(fn({{ref, size}, pids}) -> [binary_ref: ref, binary_size: size, pids_count: length(pids), pids: pids] end)
  end

  defp sort_by_fn(:pids_count) do
    fn({_, pids}) -> length(pids) end
  end

  defp sort_by_fn(:binary_size) do
    fn({{_ref, size}, _pids}) -> size end
  end
end