daemon: Reimplement ‘nr_devices’ API in OCaml.

daemon/devsparts.c

@@ -54,21 +54,6 @@ do_device_index (const char *device)
   return ret;
 }
 
-int
-do_nr_devices (void)
-{
-  size_t i;
-  CLEANUP_FREE_STRING_LIST char **devices = do_list_devices ();
-
-  if (devices == NULL)
-    return -1;
-
-  for (i = 0; devices[i] != NULL; ++i)
-    ;
-
-  return (int) i;
-}
-
 #define GUESTFSDIR "/dev/disk/guestfs"
 
 char **

daemon/devsparts.ml

@@ -89,6 +89,8 @@ and add_partitions dev =
   let parts = List.filter (fun part -> String.is_prefix part dev) parts in
   List.map ((^) "/dev/") parts
 
+let nr_devices () = List.length (list_devices ())
+
 let part_to_dev part =
   let dev, part = split_device_partition part in
   if part = 0 then

daemon/devsparts.mli

@@ -19,6 +19,8 @@
 val list_devices : unit -> string list
 val list_partitions : unit -> string list
 
+val nr_devices : unit -> int
+
 val part_to_dev : string -> string
 val part_to_partnum : string -> int
 

generator/actions_core.ml

@@ -7432,6 +7432,7 @@ See also C<guestfs_list_devices>, C<guestfs_part_to_dev>." };
 
   { defaults with
     name = "nr_devices"; added = (1, 19, 15);
+    impl = OCaml "Devsparts.nr_devices";
     style = RInt "nrdisks", [], [];
     tests = [
       InitEmpty, Always, TestResult (