support Python 3.x in importpkg

In Python 2.x, TarInfo.name is a bytes object. In Python 3.x,
TarInfo.name always is a unicode object. To avoid importpkg crashing
with an exception, we direct the Python 3.x decoding to use
surrogateescapes. Thus decoding the name boils down to checking whether
it contains surrogates.

1 files changed, 27 insertions, 4 deletions

diff --git a/importpkg.py b/importpkg.py
index dac4bb1..e8cc2fa 100755
--- a/importpkg.py
+++ b/importpkg.py
@@ -42,9 +42,32 @@ def gifhash():
     hashobj.name = "gif_sha512"
     return hashobj
 
-def decompress_tar(filelike, extension):
-    filelike = decompress(filelike, extension.decode("ascii"))
-    return tarfile.open(fileobj=filelike, mode="r|")
+if sys.version_info.major >= 3:
+    def decompress_tar(filelike, extension):
+        filelike = decompress(filelike, extension.decode("ascii"))
+        return tarfile.open(fileobj=filelike, mode="r|")
+
+    def decodetarname(name):
+        """Decoded name of a tarinfo.
+        @raises UnicodeDecodeError:
+        """
+        try:
+            name.encode("utf8", "strict")
+        except UnicodeEncodeError as e:
+            if e.reason == "surrogates not allowed":
+                name.encode("utf8", "surrogateescape").decode("utf8", "strict")
+        return name
+else:
+    def decompress_tar(filelike, extension):
+        filelike = decompress(filelike, extension.decode("ascii"))
+        return tarfile.open(fileobj=filelike, mode="r|", encoding="utf8",
+                            errors="surrogateescape")
+
+    def decodetarname(name):
+        """Decoded name of a tarinfo.
+        @raises UnicodeDecodeError:
+        """
+        return name.decode("utf8")
 
 class ProcessingFinished(Exception):
     pass
@@ -77,7 +100,7 @@ class ImportpkgExtractor(DebExtractor):
             tf = decompress_tar(filelike, name[8:])
             for name, size, hashes in get_tar_hashes(tf, self.hash_functions):
                 try:
-                    name = name.decode("utf8")
+                    name = decodetarname(name)
                 except UnicodeDecodeError:
                     print("warning: skipping filename with encoding error")
                     continue # skip files with non-utf8 encoding for now