Use file_name and link_name from PAX header

Fixes #126.

lib/tar.ml

@@ -542,11 +542,13 @@ module Header = struct
              (* GNU tar and Posix differ in interpretation of the character following ustar. For Posix, it should be '\0' but GNU tar uses ' ' *)
              String.length magic >= 5 && (String.sub magic 0 5 = "ustar") in
         let prefix = if ustar then get_hdr_prefix c else "" in
-        let file_name =
-          let file_name = get_hdr_file_name c in
-          if file_name = "" then prefix
-          else if prefix = "" then file_name
-          else Filename.concat prefix file_name in
+        let file_name = match extended.Extended.path with
+          | Some path -> path
+          | None ->
+            let file_name = get_hdr_file_name c in
+            if file_name = "" then prefix
+            else if prefix = "" then file_name
+            else Filename.concat prefix file_name in
         let file_mode = get_hdr_file_mode c in
         let user_id = match extended.Extended.user_id with
           | None -> get_hdr_user_id c
@@ -570,7 +572,9 @@ module Header = struct
         let devmajor  = if ustar then get_hdr_devmajor c else 0 in
         let devminor  = if ustar then get_hdr_devminor c else 0 in
 
-        let link_name = get_hdr_link_name c in
+        let link_name = match extended.Extended.link_path with
+          | Some link_path -> link_path
+          | None -> get_hdr_link_name c in
         Some (make ~file_mode ~user_id ~group_id ~mod_time ~link_indicator
            ~link_name ~uname ~gname ~devmajor ~devminor file_name file_size)
 

lib_test/parse_test.ml

@@ -147,6 +147,22 @@ let can_list_longlink_tar () =
       Alcotest.(check (list string)) "respects filenames" expected filenames
     ) ~finally:(fun () -> Unix.close fd)
 
+let can_list_long_pax_tar () =
+  let open Tar_unix in
+  let fd = Unix.openfile "lib_test/long-pax.tar" [ O_RDONLY; O_CLOEXEC ] 0x0 in
+  Fun.protect
+    (fun () ->
+      let all = Archive.list fd in
+      let filenames = List.map (fun h -> h.Tar.Header.file_name) all in
+      (* List.iteri (fun i x -> Printf.fprintf stderr "%d: %s\n%!" i x) filenames; *)
+      let expected = [
+        "t/";
+        "t/someveryveryverylonggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggname";
+        "t/someveryveryverylonggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggglink";
+      ] in
+      Alcotest.(check (list string)) "respects filenames" expected filenames
+    ) ~finally:(fun () -> Unix.close fd)
+
 let starts_with ~prefix s =
   let len_s = String.length s
   and len_pre = String.length prefix in
@@ -319,6 +335,7 @@ let () =
       "can_read_tar" >:: can_read_tar;
       "can write pax headers" >:: can_write_pax;
       "can read @Longlink" >:: can_list_longlink_tar;
+      "can read pax long names and links" >:: can_list_long_pax_tar;
       "can transform tars" >:: can_transform_tar;
     ]
   in