(*  Title:      Pure/ML-Systems/multithreading.ML

    Author:     Makarius

Dummy implementation of multithreading setup.

*)

signature BASIC_MULTITHREADING =

sig

  val NAMED_CRITICAL: string -> (unit -> 'a) -> 'a

  val CRITICAL: (unit -> 'a) -> 'a

end;

signature MULTITHREADING =

sig

  include BASIC_MULTITHREADING

  val trace: int ref

  val tracing: int -> (unit -> string) -> unit

  val tracing_time: Time.time -> (unit -> string) -> unit

  val available: bool

  val max_threads: int ref

  val max_threads_value: unit -> int

  val enabled: unit -> bool

  val no_interrupts: Thread.threadAttribute list

  val regular_interrupts: Thread.threadAttribute list

  val restricted_interrupts: Thread.threadAttribute list

  val with_attributes: Thread.threadAttribute list ->

    (Thread.threadAttribute list -> 'a -> 'b) -> 'a -> 'b

  val self_critical: unit -> bool

  val serial: unit -> int

end;

structure Multithreading: MULTITHREADING =

struct

(* options *)

val trace = ref (0: int);

fun tracing _ _ = ();

fun tracing_time _ _ = ();

val available = false;

val max_threads = ref (1: int);

fun max_threads_value () = 1: int;

fun enabled () = false;

val no_interrupts =

  [Thread.EnableBroadcastInterrupt false, Thread.InterruptState Thread.InterruptDefer];

val regular_interrupts =

  [Thread.EnableBroadcastInterrupt true, Thread.InterruptState Thread.InterruptAsynchOnce];

val restricted_interrupts =

  [Thread.EnableBroadcastInterrupt false, Thread.InterruptState Thread.InterruptAsynchOnce];

fun with_attributes _ f x = f [] x;

(* critical section *)

fun self_critical () = false;

fun NAMED_CRITICAL _ e = e ();

fun CRITICAL e = e ();

(* serial numbers *)

local val count = ref (0: int)

in fun serial () = (count := ! count + 1; ! count) end;

end;

structure BasicMultithreading: BASIC_MULTITHREADING = Multithreading;

open BasicMultithreading;