chroottar.py: implement Tarfile.zstopen for fileobj

zstandard.open actually consumes file objects. Hence there is little
benefit in not implementing the passing of a fileobj even though we
don't use it here.

1 files changed, 4 insertions, 5 deletions

diff --git a/examples/chroottar.py b/examples/chroottar.py
index d229956..49d9a7d 100755
--- a/examples/chroottar.py
+++ b/examples/chroottar.py
@@ -31,12 +31,11 @@ class TarFile(tarfile.TarFile):
         cls,
         name: str,
         mode: typing.Literal["r", "w", "x"] = "r",
-        fileobj: None = None,
+        fileobj: typing.BinaryIO | None = None,
     ) -> tarfile.TarFile:
         if mode not in ("r", "w", "x"):
             raise NotImplementedError(f"mode `{mode}' not implemented for zst")
-        if fileobj is not None:
-            raise NotImplementedError("zst does not support a fileobj")
+        openobj: str | typing.BinaryIO = name if fileobj is None else fileobj
         try:
             import zstandard
         except ImportError as err:
@@ -44,10 +43,10 @@ class TarFile(tarfile.TarFile):
                 "zstandard module not available"
             ) from err
         if mode == "r":
-            zfobj = zstandard.open(name, "rb")
+            zfobj = zstandard.open(openobj, "rb")
         else:
             zfobj = zstandard.open(
-                name,
+                openobj,
                 mode + "b",
                 cctx=zstandard.ZstdCompressor(write_checksum=True, threads=-1),
             )