3 files changed, 44 insertions, 0 deletions
diff --git a/lib/lib.mllib b/lib/lib.mllib
index 5f1314185e..9f29613d19 100644
--- a/lib/lib.mllib
+++ b/lib/lib.mllib
@@ -19,5 +19,6 @@ Dnet
 Unionfind
 Genarg
 Future
+RemoteCounter
 Dag
 Vcs
diff --git a/lib/remoteCounter.ml b/lib/remoteCounter.ml
new file mode 100644
index 0000000000..1983d27220
--- /dev/null
+++ b/lib/remoteCounter.ml
@@ -0,0 +1,29 @@
+(************************************************************************)
+(*  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        *)
+(************************************************************************)
+
+type 'a getter = unit -> 'a
+type 'a installer = ('a getter) -> unit
+
+let new_counter a ~incr ~build =
+  let data = ref a in
+  let m = Mutex.create () in
+  let mk_thsafe_getter f () =
+    (* - slaves must use a remote counter getter, not this one! *)
+    (* - in the main process there is a race condition between slave
+         managers (that are threads) and the main thread, hence the mutex *)
+    if !Flags.coq_slave_mode > 0 then
+      Errors.anomaly(Pp.str"Slave processes must install remote counters");
+    Mutex.lock m; let x = f () in Mutex.unlock m;
+    build x in
+  let getter = ref (mk_thsafe_getter (fun () -> data := incr !data; !data)) in
+  let installer f =
+    if !Flags.coq_slave_mode < 1 then
+      Errors.anomaly(Pp.str"Only slave processes can install a remote counter")
+    else getter := f in
+  (fun () -> !getter ()), installer
+
diff --git a/lib/remoteCounter.mli b/lib/remoteCounter.mli
new file mode 100644
index 0000000000..f17f1be3cf
--- /dev/null
+++ b/lib/remoteCounter.mli
@@ -0,0 +1,14 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2013     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+type 'a getter = unit -> 'a
+type 'a installer = ('a getter) -> unit
+
+val new_counter :
+  'a -> incr:('a -> 'a) -> build:('a -> 'b) -> 'b getter * 'b installer
+