src/Pure/System/isabelle_process.ML

fall back on synchronous message output for single-threaded SML/NJ;

(*  Title:      Pure/System/isabelle_process.ML
    Author:     Makarius

Isabelle process wrapper, based on private fifos for maximum
robustness and performance, or local socket for maximum portability.

Startup phases:
  - raw Posix process startup with uncontrolled output on stdout/stderr
  - stderr \002: ML running
  - stdin/stdout/stderr freely available (raw ML loop)
  - protocol thread initialization
  - rendezvous on system channel
  - message INIT: channels ready
*)

signature ISABELLE_PROCESS =
sig
  val is_active: unit -> bool
  val protocol_command: string -> (string list -> unit) -> unit
  val reset_tracing: unit -> unit
  val crashes: exn list Synchronized.var
  val init_fifos: string -> string -> unit
  val init_socket: string -> unit
end;

structure Isabelle_Process: ISABELLE_PROCESS =
struct

(* print mode *)

val isabelle_processN = "isabelle_process";

fun is_active () = Print_Mode.print_mode_active isabelle_processN;

val _ = Output.add_mode isabelle_processN Output.default_output Output.default_escape;
val _ = Markup.add_mode isabelle_processN YXML.output_markup;


(* protocol commands *)

local

val commands =
  Synchronized.var "Isabelle_Process.commands" (Symtab.empty: (string list -> unit) Symtab.table);

in

fun protocol_command name cmd =
  Synchronized.change commands (fn cmds =>
   (if not (Symtab.defined cmds name) then ()
    else warning ("Redefining Isabelle process command " ^ quote name);
    Symtab.update (name, cmd) cmds));

fun run_command name args =
  (case Symtab.lookup (Synchronized.value commands) name of
    NONE => error ("Undefined Isabelle process command " ^ quote name)
  | SOME cmd =>
      (Runtime.debugging cmd args handle exn =>
        error ("Isabelle process protocol failure: " ^ quote name ^ "\n" ^
          ML_Compiler.exn_message exn)));

end;


(* restricted tracing messages *)

val tracing_messages =
  Synchronized.var "tracing_messages" (Inttab.empty: int Inttab.table);

fun reset_tracing () =
  Synchronized.change tracing_messages (K Inttab.empty);

fun update_tracing () =
  (case Position.parse_id (Position.thread_data ()) of
    NONE => ()
  | SOME id =>
      let
        val ok =
          Synchronized.change_result tracing_messages (fn tab =>
            let
              val n = the_default 0 (Inttab.lookup tab id) + 1;
              val ok = n <= Options.default_int "editor_tracing_messages";
            in (ok, Inttab.update (id, n) tab) end);
      in
        if ok then ()
        else
          let
            val (text, promise) = Active.dialog_text ();
            val _ =
              writeln ("Tracing paused.  " ^ text "Stop" ^ ", or continue with next " ^
                text "100" ^ ", " ^ text "1000" ^ ", " ^ text "10000" ^ " messages?")
            val m = Markup.parse_int (Future.join promise)
              handle Fail _ => error "Stopped";
          in
            Synchronized.change tracing_messages
              (Inttab.map_default (id, 0) (fn k => k - m))
          end
      end);


(* message channels *)

local

fun chunk s = [string_of_int (size s), "\n", s];
fun flush channel = ignore (try System_Channel.flush channel);

datatype target =
  Channel of System_Channel.T |
  Mailbox of (string list * bool) Mailbox.T;

fun message do_flush target name raw_props body =
  let
    val robust_props = map (pairself YXML.embed_controls) raw_props;
    val header = YXML.string_of (XML.Elem ((name, robust_props), []));
    val msg = chunk header @ chunk body;
  in
    (case target of
      Channel channel => (List.app (fn s => System_Channel.output channel s) msg; flush channel)
    | Mailbox mbox => Mailbox.send mbox (msg, do_flush))
  end;

fun message_output mbox channel =
  let
    fun loop receive =
      (case receive mbox of
        SOME (msg, do_flush) =>
         (List.app (fn s => System_Channel.output channel s) msg;
          if do_flush then flush channel else ();
          loop (Mailbox.receive_timeout (seconds 0.02)))
      | NONE => (flush channel; loop (SOME o Mailbox.receive)));
  in fn () => loop (SOME o Mailbox.receive) end;

in

fun init_channels channel =
  let
    val _ = TextIO.StreamIO.setBufferMode (TextIO.getOutstream TextIO.stdOut, IO.LINE_BUF);
    val _ = TextIO.StreamIO.setBufferMode (TextIO.getOutstream TextIO.stdErr, IO.LINE_BUF);

    val target =
      if Multithreading.available then
        let
          val mbox = Mailbox.create ();
          val _ = Simple_Thread.fork false (message_output mbox channel);
        in Mailbox mbox end
      else Channel channel;

    fun standard_message opt_serial name body =
      if body = "" then ()
      else
        message false target name
          ((case opt_serial of SOME i => cons (Markup.serialN, Markup.print_int i) | _ => I)
            (Position.properties_of (Position.thread_data ()))) body;
  in
    Output.Private_Hooks.status_fn := standard_message NONE Markup.statusN;
    Output.Private_Hooks.report_fn := standard_message NONE Markup.reportN;
    Output.Private_Hooks.result_fn := (fn (i, s) => standard_message (SOME i) Markup.resultN s);
    Output.Private_Hooks.writeln_fn :=
      (fn s => standard_message (SOME (serial ())) Markup.writelnN s);
    Output.Private_Hooks.tracing_fn :=
      (fn s => (update_tracing (); standard_message (SOME (serial ())) Markup.tracingN s));
    Output.Private_Hooks.warning_fn :=
      (fn s => standard_message (SOME (serial ())) Markup.warningN s);
    Output.Private_Hooks.error_fn :=
      (fn (i, s) => standard_message (SOME i) Markup.errorN s);
    Output.Private_Hooks.protocol_message_fn := message true target Markup.protocolN;
    Output.Private_Hooks.urgent_message_fn := ! Output.Private_Hooks.writeln_fn;
    Output.Private_Hooks.prompt_fn := ignore;
    message true target Markup.initN [] (Session.welcome ())
  end;

end;


(* protocol loop -- uninterruptible *)

val crashes = Synchronized.var "Isabelle_Process.crashes" ([]: exn list);

local

fun recover crash =
  (Synchronized.change crashes (cons crash);
    warning "Recovering from Isabelle process crash -- see also Isabelle_Process.crashes");

fun read_chunk channel len =
  let
    val n =
      (case Int.fromString len of
        SOME n => n
      | NONE => error ("Isabelle process: malformed chunk header " ^ quote len));
    val chunk = System_Channel.inputN channel n;
    val m = size chunk;
  in
    if m = n then chunk
    else error ("Isabelle process: bad chunk (" ^ string_of_int m ^ " vs. " ^ string_of_int n ^ ")")
  end;

fun read_command channel =
  (case System_Channel.input_line channel of
    NONE => raise Runtime.TERMINATE
  | SOME line => map (read_chunk channel) (space_explode "," line));

fun worker_guest e =
  Future.worker_guest "Isabelle_Process.loop" (Future.new_group NONE) e ();

in

fun loop channel =
  let val continue =
    (case read_command channel of
      [] => (Output.error_msg "Isabelle process: no input"; true)
    | name :: args => (worker_guest (fn () => run_command name args); true))
    handle Runtime.TERMINATE => false
      | exn => (Output.error_msg (ML_Compiler.exn_message exn) handle crash => recover crash; true);
  in if continue then loop channel else () end;

end;


(* init *)

val default_modes1 =
  [Syntax_Trans.no_bracketsN, Syntax_Trans.no_type_bracketsN, Graph_Display.active_graphN];
val default_modes2 = [Symbol.xsymbolsN, isabelle_processN, Pretty.symbolicN];

val init = uninterruptible (fn _ => fn rendezvous =>
  let
    val _ = Output.physical_stderr Symbol.STX;

    val _ = Printer.show_markup_default := true;
    val _ = Context.set_thread_data NONE;
    val _ =
      Unsynchronized.change print_mode
        (fn mode => (mode @ default_modes1) |> fold (update op =) default_modes2);

    val channel = rendezvous ();
    val _ = init_channels channel;
    val _ = Session.init_protocol_handlers ();
  in loop channel end);

fun init_fifos fifo1 fifo2 = init (fn () => System_Channel.fifo_rendezvous fifo1 fifo2);
fun init_socket name = init (fn () => System_Channel.socket_rendezvous name);


(* options *)

val _ =
  protocol_command "Isabelle_Process.options"
    (fn [options_yxml] =>
      let val options = Options.decode (YXML.parse_body options_yxml) in
        Options.set_default options;
        Future.ML_statistics := true;
        Multithreading.trace := Options.int options "threads_trace";
        Multithreading.max_threads := Options.int options "threads";
        Goal.skip_proofs := Options.bool options "editor_skip_proofs";
        Goal.parallel_proofs := (if Options.int options "parallel_proofs" > 0 then 3 else 0)
      end);

end;