Major changes

- Remove Archive modules, and rework IO-specific modules (tar-unix etc);
  still work in progress
- Add `Tar.HEADERREADER` and `Tar.HEADERWRITER` module types, and rename
  `Tar.{READER,WRITER}.t` to `io`.
- When reading the compatibility level is no longer considered. In most
  cases the compatibility level was not enforced, and the semantics were
  very unclear.
- Better support for GNU LongLink/LongName
- Add a separate `write_global` function for writing a global
  `Tar.Header.Extended.t`. This allows writing an archive with a PAX
  comment and nothing else.

This is still work in progress.

CHANGES.md

@@ -2,6 +2,15 @@
 
 - `tar`: support pax Global Extended Headers. This adds state to tar parsing.
   (#119, #120, @MisterDA)
+- Support GNU LongLink and LongName. Prior, `Tar.HeaderWriter` and
+  `Tar.HeaderReader` supported both, but `Tar.Header.Link` only had `LongLink`
+  and (de)serialized to (from) GNU LongName.
+- Compatibility level when reading / parsing is removed. Only GNU
+  LongLink/LongName extensions were affected by the compatibility level when
+  reading.
+- Add module types `Tar.HEADERREADER` and `Tar.HEADERWRITER` describing the
+  output of `Tar.HeaderReader` and `Tar.HeaderWriter` respectively.
+- Types `Tar.READER.t` and `Tar.WRITER.t` are renamed to `io`.
 
 ## v2.5.1 (2023-06-20)
 

bin/otar.ml

@@ -21,12 +21,12 @@ module Tar_gz = Tar_gz.Make
           let ( >>= ) x f = f x
           let return x = x end)
   (struct type out_channel = Stdlib.out_channel
-          type 'a t = 'a
+          type 'a io = 'a
           let really_write oc cs =
             let str = Cstruct.to_string cs in
             output_string oc str end)
   (struct type in_channel = Stdlib.in_channel
-          type 'a t = 'a
+          type 'a io = 'a
           let really_read ic cs =
             let len = Cstruct.length cs in
             let buf = Bytes.create len in
@@ -104,8 +104,8 @@ let bytes_to_size ?(decimals = 2) ppf = function
 let list filename =
   let ic = open_in filename in
   let ic = Tar_gz.of_in_channel ~internal:(Cstruct.create 0x1000) ic in
-  let rec go global () = match Tar_gz.get_next_header ~level:Tar.Header.Ustar ~global ic with
-    | (hdr, global) ->
+  let rec go global () = match Tar_gz.HeaderReader.read ~global ic with
+    | Ok (hdr, global) ->
       Format.printf "%s (%s, %a)\n%!"
         hdr.Tar.Header.file_name
         (Tar.Header.Link.to_string hdr.link_indicator)
@@ -117,7 +117,7 @@ let list filename =
       let to_skip = Tar.Header.(Int64.to_int (to_sectors hdr) * length) in
       Tar_gz.skip ic to_skip ;
       go global ()
-    | exception Tar.Header.End_of_stream -> () in
+    | Error `Eof -> () in
   go None ()
 
 let () = match Sys.argv with