(*  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 tracing_messages: int Unsynchronized.ref;

  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 = Unsynchronized.ref 100;

val command_tracing_messages =

  Synchronized.var "command_tracing_messages" (Inttab.empty: int Inttab.table);

fun reset_tracing () =

  Synchronized.change command_tracing_messages (K Inttab.empty);

fun update_tracing () =

  (case Position.parse_id (Position.thread_data ()) of

    NONE => ()

  | SOME id =>

      let

        val (n, ok) =

          Synchronized.change_result command_tracing_messages (fn tab =>

            let

              val n = the_default 0 (Inttab.lookup tab id) + 1;

              val ok = n <= ! tracing_messages;

            in ((n, 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 command_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 message do_flush mbox 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), []));

  in Mailbox.send mbox (chunk header @ chunk body, do_flush) end;

fun standard_message mbox opt_serial name body =

  if body = "" then ()

  else

    message false mbox name

      ((case opt_serial of SOME i => cons (Markup.serialN, Markup.print_int i) | _ => I)

        (Position.properties_of (Position.thread_data ()))) body;

fun message_output mbox channel =

  let

    fun flush () = ignore (try System_Channel.flush channel);

    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 () else ();

          loop (Mailbox.receive_timeout (seconds 0.02)))

      | NONE => (flush (); 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 mbox = Mailbox.create () : (string list * bool) Mailbox.T;

    val _ = Simple_Thread.fork false (message_output mbox channel);

  in

    Output.Private_Hooks.status_fn := standard_message mbox NONE Markup.statusN;

    Output.Private_Hooks.report_fn := standard_message mbox NONE Markup.reportN;

    Output.Private_Hooks.result_fn :=

      (fn (i, s) => standard_message mbox (SOME i) Markup.resultN s);

    Output.Private_Hooks.writeln_fn :=

      (fn s => standard_message mbox (SOME (serial ())) Markup.writelnN s);

    Output.Private_Hooks.tracing_fn :=

      (fn s => (update_tracing (); standard_message mbox (SOME (serial ())) Markup.tracingN s));

    Output.Private_Hooks.warning_fn :=

      (fn s => standard_message mbox (SOME (serial ())) Markup.warningN s);

    Output.Private_Hooks.error_fn :=

      (fn (i, s) => standard_message mbox (SOME i) Markup.errorN s);

    Output.Private_Hooks.protocol_message_fn := message true mbox Markup.protocolN;

    Output.Private_Hooks.urgent_message_fn := ! Output.Private_Hooks.writeln_fn;

    Output.Private_Hooks.prompt_fn := ignore;

    message true mbox 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));

in

fun loop channel =

  let val continue =

    (case read_command channel of

      [] => (Output.error_msg "Isabelle process: no input"; true)

    | name :: args => (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];

fun init rendezvous = ignore (Simple_Thread.fork false (fn () =>

  let

    val _ = OS.Process.sleep (seconds 0.5);  (*yield to raw ML toplevel*)

    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;

  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";

        if Multithreading.max_threads_value () < 2

        then Multithreading.max_threads := 2 else ();

        Goal.skip_proofs := Options.bool options "editor_skip_proofs";

        Goal.parallel_proofs := (if Options.int options "parallel_proofs" > 0 then 3 else 0);

        tracing_messages := Options.int options "editor_tracing_messages"

      end);

end;