ocaml: add helpers for Some/None option types.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

diff --git a/tools/ocaml/libs/xl/xenlight_stubs.c b/tools/ocaml/libs/xl/xenlight_stubs.c
index 4b19e9a858cb02c3d6fc663088899701f4610e36..d3e4751a365a79904db2c7537912d51fef1dbe40 100644 (file)
--- a/tools/ocaml/libs/xl/xenlight_stubs.c
+++ b/tools/ocaml/libs/xl/xenlight_stubs.c
@@ -130,6 +130,19 @@ static int string_string_tuple_array_val (caml_gc *gc, char ***c_val, value v)
 
 #endif
 
+/* Option type support as per http://www.linux-nantes.org/~fmonnier/ocaml/ocaml-wrapping-c.php */
+#define Val_none Val_int(0)
+#define Some_val(v) Field(v,0)
+
+static value Val_some(value v)
+{
+       CAMLparam1(v);
+       CAMLlocal1(some);
+       some = caml_alloc(1, 0);
+       Store_field(some, 0, v);
+       CAMLreturn(some);
+}
+
 static value Val_mac (libxl_mac *c_val)
 {
        CAMLparam0();
@@ -205,14 +218,13 @@ static value Val_topologyinfo(libxl_topologyinfo *c_val)
 
        topologyinfo = caml_alloc_tuple(c_val->coremap.entries);
        for (i = 0; i < c_val->coremap.entries; i++) {
-               v = Val_int(0); /* None */
+               v = Val_none;
                if (c_val->coremap.array[i] != LIBXL_CPUARRAY_INVALID_ENTRY) {
                        topology = caml_alloc_tuple(3);
                        Store_field(topology, 0, Val_int(c_val->coremap.array[i]));
                        Store_field(topology, 1, Val_int(c_val->socketmap.array[i]));
                        Store_field(topology, 2, Val_int(c_val->nodemap.array[i]));
-                       v = caml_alloc(1, 0); /* Some */
-                       Store_field(v, 0, topology);
+                       v = Val_some(topology);
                }
                Store_field(topologyinfo, i, v);
        }