Source file angstrom_lwt_unix.ml

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open Angstrom.Buffered
open Lwt

let default_pushback () = return_unit

let rec buffered_state_loop pushback state in_chan bytes =
  let size = Bytes.length bytes in
  match state with
  | Partial k ->
    Lwt_io.read_into in_chan bytes 0 size
    >|= begin function
      | 0   -> k `Eof
      | len ->
        assert (len > 0);
        k (`String (Bytes.(unsafe_to_string (sub bytes 0 len))))
    end
    >>= fun state' -> pushback ()
    >>= fun ()     -> buffered_state_loop pushback state' in_chan bytes
  | state -> return state

let handle_parse_result state =
  match state_to_unconsumed state with
  | None    -> assert false
  | Some us -> us, state_to_result state

let parse ?(pushback=default_pushback) p in_chan =
  let size  = Lwt_io.buffer_size in_chan in
  let bytes = Bytes.create size in
  buffered_state_loop pushback (parse ~initial_buffer_size:size p) in_chan bytes
  >|= handle_parse_result

let with_buffered_parse_state ?(pushback=default_pushback) state in_chan =
  let size  = Lwt_io.buffer_size in_chan in
  let bytes = Bytes.create size in
  begin match state with
  | Partial _ -> buffered_state_loop pushback state in_chan bytes
  | _         -> return state
  end
  >|= handle_parse_result

let async_many e k =
  Angstrom.(skip_many (e <* commit >>| k) <?> "async_many")

let parse_many p write in_chan =
  let wait = ref (default_pushback ()) in
  let k x = wait := write x in
  let pushback () = !wait in
  parse ~pushback (async_many p k) in_chan