SMAPI parallel operations limiter

limiter.ml

module Smapi_limiter = struct
  let limit = ref 10
  let m = Mutex.create ()
  let c = Condition.create ()

  let set_limit n = limit := n

  let get_token () =
    Mutex.execute m (fun () ->
        while !limit=0 do
          Condition.wait c m
        done;
        limit := !limit - 1)

  let release_token () =
    Mutex.execute m (fun () ->
        limit := !limit + 1;
        Condition.signal c)

  let with_limit f =
    get_token ();
    Pervasiveext.finally f release_token
 end