(*  Title:      Pure/System/isabelle_process.ML

    Author:     Makarius

Isabelle process wrapper.

General format of process output:

  (1) message = "\002"  header chunk  body chunk

  (2) chunk = size (ASCII digits)  \n  content (YXML)

*)

signature ISABELLE_PROCESS =

sig

  val isabelle_processN: string

  val init: string -> unit

end;

structure Isabelle_Process: ISABELLE_PROCESS =

struct

(* print modes *)

val isabelle_processN = "isabelle_process";

val _ = Output.add_mode isabelle_processN Output.default_output Output.default_escape;

val _ = Markup.add_mode isabelle_processN YXML.output_markup;

(* message markup *)

local

fun chunk s = string_of_int (size s) ^ "\n" ^ s;

fun message _ _ _ "" = ()

  | message out_stream ch props body =

      let

        val header = YXML.string_of (XML.Elem (ch, map (pairself YXML.binary_text) props, []));

        val msg = Symbol.STX ^ chunk header ^ chunk body;

      in TextIO.output (out_stream, msg) (*atomic output*) end;

in

fun standard_message out_stream ch body =

  message out_stream ch (Position.properties_of (Position.thread_data ())) body;

fun init_message out_stream =

  message out_stream "A" [(Markup.pidN, process_id ())] (Session.welcome ());

end;

(* channels *)

local

fun auto_flush stream =

  let

    val _ = TextIO.StreamIO.setBufferMode (TextIO.getOutstream stream, IO.BLOCK_BUF);

    fun loop () =

      (OS.Process.sleep (Time.fromMilliseconds 50); try TextIO.flushOut stream; loop ());

  in loop end;

in

fun setup_channels out =

  let

    val path = File.platform_path (Path.explode out);

    val out_stream = TextIO.openOut path;  (*fifo blocks until reader is ready*)

    val _ = OS.FileSys.remove path;  (*prevent alien access, indicate writer is ready*)

    val _ = Simple_Thread.fork false (auto_flush out_stream);

    val _ = Simple_Thread.fork false (auto_flush TextIO.stdOut);

    val _ = Simple_Thread.fork false (auto_flush TextIO.stdErr);

  in

    Output.status_fn   := standard_message out_stream "B";

    Output.writeln_fn  := standard_message out_stream "C";

    Output.tracing_fn  := standard_message out_stream "D";

    Output.warning_fn  := standard_message out_stream "E";

    Output.error_fn    := standard_message out_stream "F";

    Output.debug_fn    := standard_message out_stream "G";

    Output.priority_fn := ! Output.writeln_fn;

    Output.prompt_fn   := ignore;

    out_stream

  end;

end;

(* init *)

fun init out =

 (Unsynchronized.change print_mode

    (fold (update op =) [isabelle_processN, Keyword.keyword_status_reportN, Pretty.symbolicN]);

  setup_channels out |> init_message;

  quick_and_dirty := true;  (* FIXME !? *)

  Keyword.report ();

  Output.status (Markup.markup Markup.ready "");

  Isar.toplevel_loop {init = true, welcome = false, sync = true, secure = true});

end;