- Add a shared AUFS utility lib and change both changes and streamlayerformat to use it

- Add UI for selecting whether to pull the tag, the repo, or the squashed tag

util/changes.py

@@ -1,16 +1,10 @@
 import marisa_trie
 import os
 import tarfile
-
-
-AUFS_METADATA = u'.wh..wh.'
-
-AUFS_WHITEOUT = u'.wh.'
-AUFS_WHITEOUT_PREFIX_LENGTH = len(AUFS_WHITEOUT)
+from aufs import is_aufs_metadata, get_deleted_prefix
 
 ALLOWED_TYPES = {tarfile.REGTYPE, tarfile.AREGTYPE}
 
-
 def files_and_dirs_from_tar(source_stream, removed_prefix_collector):
   try:
     tar_stream = tarfile.open(mode='r|*', fileobj=source_stream)
@@ -20,22 +14,19 @@ def files_and_dirs_from_tar(source_stream, removed_prefix_collector):
   
   for tar_info in tar_stream:
     absolute = os.path.relpath(tar_info.name.decode('utf-8'), './')
-    dirname = os.path.dirname(absolute)
-    filename = os.path.basename(absolute)
 
-    # Skip directories and metadata
-    if (filename.startswith(AUFS_METADATA) or
-        absolute.startswith(AUFS_METADATA)):
-      # Skip
+    # Skip metadata.
+    if is_aufs_metadata(absolute):
       continue
 
-    elif filename.startswith(AUFS_WHITEOUT):
-      removed_filename = filename[AUFS_WHITEOUT_PREFIX_LENGTH:]
-      removed_prefix = os.path.join('/', dirname, removed_filename)
-      removed_prefix_collector.add(removed_prefix)
+    # Add prefixes of removed paths to the collector.
+    deleted_prefix = get_deleted_prefix(absolute)
+    if deleted_prefix is not None:
+      deleted_prefix.add(deleted_prefix)
       continue
 
-    elif tar_info.type in ALLOWED_TYPES:
+    # Otherwise, yield the path if it is in the allowed types.
+    if tar_info.type in ALLOWED_TYPES:
       yield '/' + absolute