(*  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.

*)

signature ISABELLE_PROCESS =

sig

  val is_active: unit -> bool

  val protocol_command: string -> (string list -> unit) -> unit

  val reset_tracing: Document_ID.exec -> 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 protocol 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 protocol command " ^ quote name)

  | SOME cmd =>

      (Toplevel.debugging cmd args handle exn =>

        error ("Isabelle protocol command 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 exec_id =

  Synchronized.change tracing_messages (Inttab.delete_safe exec_id);

fun update_tracing () =

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

    NONE => ()

  | SOME exec_id =>

      let

        val ok =

          Synchronized.change_result tracing_messages (fn tab =>

            let

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

              val ok = n <= Options.default_int "editor_tracing_messages";

            in (ok, Inttab.update (exec_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 (exec_id, 0) (fn k => k - m))

          end

      end);

(* output channels *)

val serial_props = Markup.serial_properties o serial;

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 msg_channel = Message_Channel.make channel;

    fun message name props body =

      Message_Channel.send msg_channel (Message_Channel.message name props body);

    fun standard_message props name body =

      if body = "" then ()

      else

        message name

          (fold_rev Properties.put props (Position.properties_of (Position.thread_data ()))) body;

  in

    Output.Internal.status_fn := standard_message [] Markup.statusN;

    Output.Internal.report_fn := standard_message [] Markup.reportN;

    Output.Internal.result_fn :=

      (fn props => fn s => standard_message (props @ serial_props ()) Markup.resultN s);

    Output.Internal.writeln_fn := (fn s => standard_message (serial_props ()) Markup.writelnN s);

    Output.Internal.tracing_fn :=

      (fn s => (update_tracing (); standard_message (serial_props ()) Markup.tracingN s));

    Output.Internal.warning_fn := (fn s => standard_message (serial_props ()) Markup.warningN s);

    Output.Internal.error_message_fn :=

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

    Output.Internal.protocol_message_fn := message Markup.protocolN;

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

    Output.Internal.prompt_fn := ignore;

    message Markup.initN [] (Session.welcome ());

    msg_channel

  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 header " ^ quote len));

    val chunk = System_Channel.inputN channel n;

    val i = size chunk;

  in

    if i <> n then

      error ("Isabelle process: bad chunk (unexpected EOF after " ^

        string_of_int i ^ " of " ^ string_of_int n ^ " bytes)")

    else chunk

  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 task_context e =

  Future.task_context "Isabelle_Process.loop" (Future.new_group NONE) e ();

in

fun loop channel =

  let val continue =

    (case read_command channel of

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

    | name :: args => (task_context (fn () => run_command name args); true))

    handle Runtime.TERMINATE => false

      | exn => (ML_Compiler.exn_error_message exn handle crash => recover crash; true);

  in

    if continue then loop channel

    else (Future.shutdown (); Execution.reset (); ())

  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 _ = SHA1_Samples.test ()

      handle exn as Fail msg => (Output.physical_stderr (msg ^ "\n"); reraise exn);

    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 msg_channel = init_channels channel;

    val _ = Session.init_protocol_handlers ();

    val _ = loop channel;

  in Message_Channel.shutdown msg_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);

end;