STM: move out a couple of submodules

These modules are not as reusable as one may want them to be, but
moving them out simplifies a little STM.

1 files changed, 73 insertions, 0 deletions

diff --git a/lib/workerPool.ml b/lib/workerPool.ml
new file mode 100644
index 0000000000..fcae4f20d6
--- /dev/null
+++ b/lib/workerPool.ml
@@ -0,0 +1,73 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2012     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+module Make(Worker : sig
+  type process
+  val spawn :
+      ?prefer_sock:bool -> ?env:string array -> string -> string array ->
+      process * in_channel * out_channel
+end) = struct
+
+type worker_id = int
+type spawn =
+  args:string array -> env:string array -> unit ->
+    in_channel * out_channel * Worker.process
+
+let slave_managers = ref None
+
+let n_workers () = match !slave_managers with
+  | None -> 0
+  | Some managers -> Array.length managers
+let is_empty () = !slave_managers = None
+
+let magic_no = 17
+
+let master_handshake worker_id ic oc =
+  try
+    Marshal.to_channel oc magic_no [];  flush oc;
+    let n = (Marshal.from_channel ic : int) in
+    if n <> magic_no then begin
+      Printf.eprintf "Handshake with %d failed: protocol mismatch\n" worker_id;
+      exit 1;
+    end
+  with e when Errors.noncritical e ->
+    Printf.eprintf "Handshake with %d failed: %s\n"
+      worker_id (Printexc.to_string e);
+    exit 1
+
+let respawn n ~args ~env () =
+  let proc, ic, oc = Worker.spawn ~env Sys.argv.(0) args in
+  master_handshake n ic oc;
+  ic, oc, proc
+
+let init ~size:n ~manager:manage_slave =
+  slave_managers := Some
+    (Array.init n (fun x ->
+       let cancel = ref false in
+       cancel, Thread.create (manage_slave ~cancel (x+1)) (respawn (x+1))))
+
+let cancel n =
+  match !slave_managers with
+  | None -> ()
+  | Some a ->
+      let switch, _ = a.(n) in
+      switch := true
+      
+let worker_handshake slave_ic slave_oc =
+  try
+    let v = (Marshal.from_channel slave_ic : int) in
+    if v <> magic_no then begin
+      prerr_endline "Handshake failed: protocol mismatch\n";
+      exit 1;
+    end;
+    Marshal.to_channel slave_oc v []; flush slave_oc;
+  with e when Errors.noncritical e ->
+    prerr_endline ("Handshake failed: " ^ Printexc.to_string e);
+    exit 1
+
+end