Harmonize Tar_unix and Tar_lwt_unix

unix/tar_lwt_unix.ml

@@ -40,14 +40,8 @@ module Io = struct
 end
 
 include Io
-module HR = Tar.HeaderReader(Lwt)(Io)
-module HW = Tar.HeaderWriter(Lwt)(Io)
-
-let get_next_header ~global ic =
-  HR.read ~global ic
-  >>= function
-  | Error `Eof -> Lwt.return None
-  | Ok hdrs -> Lwt.return (Some hdrs)
+module HeaderReader = Tar.HeaderReader(Lwt)(Io)
+module HeaderWriter = Tar.HeaderWriter(Lwt)(Io)
 
 (** Return the header needed for a particular file on disk *)
 let header_of_file ?level (file: string) : Tar.Header.t Lwt.t =

unix/tar_lwt_unix.mli

@@ -24,12 +24,12 @@ val really_write: Lwt_unix.file_descr -> Cstruct.t -> unit Lwt.t
 (** [really_write fd buf] writes the full contents of [buf] to
     [fd] or fails with {!Stdlib.End_of_file}. *)
 
-(** Returns the next header block or None if two consecutive
-    zero-filled blocks are discovered. Assumes stream is positioned at the
-    possible start of a header block.
-    @raise Stdlib.End_of_file if the stream unexpectedly fails. *)
-val get_next_header : global:Tar.Header.Extended.t option -> Lwt_unix.file_descr ->
-                      (Tar.Header.t * Tar.Header.Extended.t option) option Lwt.t
+val skip : Lwt_unix.file_descr -> int -> unit Lwt.t
+(** [skip fd n] reads [n] bytes from [fd] and discards them. If possible, you
+    should use [Lwt_unix.lseek fd n Lwt_unix.SEEK_CUR] instead. *)
 
 (** Return the header needed for a particular file on disk. *)
 val header_of_file : ?level:Tar.Header.compatibility -> string -> Tar.Header.t Lwt.t
+
+module HeaderReader : Tar.HEADERREADER with type in_channel = Lwt_unix.file_descr and type 'a io = 'a Lwt.t
+module HeaderWriter : Tar.HEADERWRITER with type out_channel = Lwt_unix.file_descr and type 'a io = 'a Lwt.t

unix/tar_unix.mli

@@ -25,6 +25,8 @@ val really_write: Unix.file_descr -> Cstruct.t -> unit
     or {!Stdlib.End_of_file}. *)
 
 val skip : Unix.file_descr -> int -> unit
+(** [skip fd n] reads [n] bytes from [fd] and discards them. If possible, you
+    should use [Unix.lseek fd n Unix.SEEK_CUR] instead. *)
 
 (** Return the header needed for a particular file on disk. *)
 val header_of_file : ?level:Tar.Header.compatibility -> string -> Tar.Header.t