ocaml: eventchn: add a 'type t' to represent an event channel

It's a common OCaml convention to add a 'type t' in a module to
represent the main "thing" that the module is about. We add an
opaque type t and to_int/of_int functions for those who really
need it, in particular:

  1. to_int is needed for debug logging; and
  2. both to_int and of_int are needed for anyone who communicates
     a port number through xenstore.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

2 files changed, 17 insertions, 6 deletions

diff --git a/tools/ocaml/libs/eventchn/xeneventchn.ml b/tools/ocaml/libs/eventchn/xeneventchn.ml
index 79ad9b1e95..acebe10c6f 100644
--- a/tools/ocaml/libs/eventchn/xeneventchn.ml
+++ b/tools/ocaml/libs/eventchn/xeneventchn.ml
@@ -20,6 +20,9 @@ type handle
 
 external init: unit -> handle = "stub_eventchn_init"
 external fd: handle -> Unix.file_descr = "stub_eventchn_fd"
+
+type t = int
+
 external notify: handle -> int -> unit = "stub_eventchn_notify"
 external bind_interdomain: handle -> int -> int -> int = "stub_eventchn_bind_interdomain"
 external bind_dom_exc_virq: handle -> int = "stub_eventchn_bind_dom_exc_virq"
@@ -27,4 +30,7 @@ external unbind: handle -> int -> unit = "stub_eventchn_unbind"
 external pending: handle -> int = "stub_eventchn_pending"
 external unmask: handle -> int -> unit = "stub_eventchn_unmask"
 
+let to_int x = x
+let of_int x = x
+
 let _ = Callback.register_exception "eventchn.error" (Error "register_callback")
diff --git a/tools/ocaml/libs/eventchn/xeneventchn.mli b/tools/ocaml/libs/eventchn/xeneventchn.mli
index 394acc2821..2b582cdaaf 100644
--- a/tools/ocaml/libs/eventchn/xeneventchn.mli
+++ b/tools/ocaml/libs/eventchn/xeneventchn.mli
@@ -18,14 +18,19 @@ exception Error of string
 
 type handle
 
+type t
+
+val to_int: t -> int
+val of_int: int -> t
+
 external init : unit -> handle = "stub_eventchn_init"
 external fd: handle -> Unix.file_descr = "stub_eventchn_fd"
 
-external notify : handle -> int -> unit = "stub_eventchn_notify"
-external bind_interdomain : handle -> int -> int -> int
+external notify : handle -> t -> unit = "stub_eventchn_notify"
+external bind_interdomain : handle -> int -> int -> t
   = "stub_eventchn_bind_interdomain"
-external bind_dom_exc_virq : handle -> int = "stub_eventchn_bind_dom_exc_virq"
-external unbind : handle -> int -> unit = "stub_eventchn_unbind"
-external pending : handle -> int = "stub_eventchn_pending"
-external unmask : handle -> int -> unit
+external bind_dom_exc_virq : handle -> t = "stub_eventchn_bind_dom_exc_virq"
+external unbind : handle -> t -> unit = "stub_eventchn_unbind"
+external pending : handle -> t = "stub_eventchn_pending"
+external unmask : handle -> t -> unit
   = "stub_eventchn_unmask"