XSI-19 locate VHD footer based on file size

I order to locate the footer in a VHD file or stream, the total length
of that file or stream must be known. This commit passes it when it is
known. This depends on a corresponding change in the ocaml-vhd library.

Signed-off-by: Christian Lindig <christian.lindig@citrix.com>

cli/get_vhd_vsize.ml

@@ -14,16 +14,19 @@ let get_vhd_vsize filename =
     | End -> return ()
     | Cons (hd, tl) ->
       begin match hd with
-      | Fragment.Footer x ->
-	let size = x.Footer.current_size in
-	Printf.printf "%Ld\n" size;
-	exit 0
-      | _ ->
-	()
+        | Fragment.Footer x ->
+          let size = x.Footer.current_size in
+          Printf.printf "%Ld\n" size;
+          exit 0
+        | _ ->
+          ()
       end;
       tl () >>= fun x ->
-      loop x in
-  openstream (Input.of_fd (Vhd_format_lwt.IO.to_file_descr fd)) >>= fun stream ->
+      loop x
+  in
+  Vhd_format_lwt.IO.get_file_size filename >>= fun file_size ->
+  openstream (Some file_size)
+    (Input.of_fd (Vhd_format_lwt.IO.to_file_descr fd)) >>= fun stream ->
   loop stream >>= fun () -> Vhd_format_lwt.IO.close fd
 
 let _ =

src/impl.ml

@@ -108,7 +108,8 @@ let contents common filename =
         end;
         tl () >>= fun x ->
         loop x in
-      openstream (Input.of_fd (Vhd_format_lwt.IO.to_file_descr fd)) >>= fun stream ->
+      Vhd_format_lwt.IO.get_file_size filename >>= fun size ->
+      openstream (Some size) (Input.of_fd (Vhd_format_lwt.IO.to_file_descr fd)) >>= fun stream ->
       loop stream in
     Lwt_main.run t;
     `Ok ()
@@ -481,7 +482,7 @@ let serve_vhd_to_raw total_size c dest prezeroed progress _ _ =
       (match !p with Some p -> p blocks_seen | None -> ());
       tl () >>= loop block_size_sectors_shift this_block blocks_seen
     | Cons (_, tl) -> tl () >>= loop block_size_sectors_shift last_block blocks_seen in
-  openstream c >>= fun stream ->
+  openstream (Some total_size) c >>= fun stream ->
   loop 0 (-1L) 0L stream
 
 let serve_tar_to_raw total_size c dest prezeroed progress expected_prefix ignore_checksums =