cmds.posix.Tar: Add command

Add a "jw-pkg posix tar" command. Currently the only thing that can be done with it is extracting.
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/cmds/posix/tar/Cmd.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+
+from argparse import Namespace, ArgumentParser
+from contextlib import asynccontextmanager
+
+from ..Cmd import Cmd as Base
+from ..CmdTar import CmdTar as Parent
+
+from ....lib.TarIo import TarIo
+from ....lib.ProcFilterGpg import ProcFilterGpg
+from ....lib.FileContext import FileContext
+
+class Cmd(Base): # export
+
+    def __init__(self, parent: Parent, name: str, help: str) -> None:
+        super().__init__(parent, name, help)
+        self.__tar_io: None = None
+
+    @asynccontextmanager
+    async def ctx(self, **kwargs) -> TarIo:
+        async with TarIo.create(src_uri=self.app.args.archive_path, **kwargs) as ret:
+            ret.src.add_proc_filter(FileContext.Direction.In, ProcFilterGpg(ec=self.app.exec_context))
+            yield ret
+
+    def add_arguments(self, parser: ArgumentParser) -> None:
+        super().add_arguments(parser)
+        parser.add_argument('-f', '--archive-path', required=True, help='Archive path')