mllib: move remove_duplicates from v2v

Simple code motion.

mllib/common_utils.ml

@@ -297,6 +297,15 @@ let sort_uniq ?(cmp = Pervasives.compare) xs =
   let xs = uniq ~cmp xs in
   xs
 
+let remove_duplicates xs =
+  let h = Hashtbl.create (List.length xs) in
+  let rec loop = function
+    | [] -> []
+    | x :: xs when Hashtbl.mem h x -> xs
+    | x :: xs -> Hashtbl.add h x true; x :: loop xs
+  in
+  loop xs
+
 let push_back xsp x = xsp := !xsp @ [x]
 let push_front x xsp = xsp := x :: !xsp
 let pop_back xsp =

mllib/common_utils.mli

@@ -147,6 +147,12 @@ val uniq : ?cmp:('a -> 'a -> int) -> 'a list -> 'a list
 val sort_uniq : ?cmp:('a -> 'a -> int) -> 'a list -> 'a list
 (** Sort and uniquify a list. *)
 
+val remove_duplicates : 'a list -> 'a list
+(** Remove duplicates from an unsorted list; useful when the order
+    of the elements matter.
+
+    Please use [sort_uniq] when the order does not matter. *)
+
 val push_back : 'a list ref -> 'a -> unit
 val push_front : 'a -> 'a list ref -> unit
 val pop_back : 'a list ref -> 'a

v2v/utils.ml

@@ -81,15 +81,6 @@ let compare_app2_versions app1 app2 =
       compare_version app1.Guestfs.app2_release app2.Guestfs.app2_release
   )
 
-let remove_duplicates xs =
-  let h = Hashtbl.create (List.length xs) in
-  let rec loop = function
-    | [] -> []
-    | x :: xs when Hashtbl.mem h x -> xs
-    | x :: xs -> Hashtbl.add h x true; x :: loop xs
-  in
-  loop xs
-
 let du filename =
   (* There's no OCaml binding for st_blocks, so run coreutils 'du'. *)
   let cmd =

v2v/utils.mli

@@ -46,9 +46,6 @@ val find_uefi_firmware : string -> Uefi.uefi_firmware
 val compare_app2_versions : Guestfs.application2 -> Guestfs.application2 -> int
 (** Compare two app versions. *)
 
-val remove_duplicates : 'a list -> 'a list
-(** Remove duplicates from a list. *)
-
 val du : string -> int64
 (** Return the true size of a file in bytes, including any wasted
     space caused by internal fragmentation (the overhead of using