Complete the diff generating functionality.

util/changes.py

@@ -1,5 +1,6 @@
 import marisa_trie
 import os
+import tarfile
 
 
 AUFS_METADATA = u'.wh..wh.'
@@ -8,33 +9,34 @@ AUFS_WHITEOUT = u'.wh.'
 AUFS_WHITEOUT_PREFIX_LENGTH = len(AUFS_WHITEOUT)
 
 
-def files_and_dirs(root_path, removed_prefix_collector):
-  for root, dirs, files in os.walk(unicode(root_path)):
+def files_and_dirs_from_tar(source_stream, removed_prefix_collector):
+  tar_stream = tarfile.open(mode='r|*', fileobj=source_stream)
+  
+  for tar_info in tar_stream:
+    absolute = os.path.relpath(unicode(tar_info.name), './')
+    filename = os.path.basename(absolute)
 
-    rel_root = os.path.relpath(root, root_path)
-    yield rel_root
+    if (filename.startswith(AUFS_METADATA) or
+        absolute.startswith(AUFS_METADATA)):
+      # Skip
+      continue
 
-    for one_file in files:
-      if one_file.startswith(AUFS_METADATA):
-        # Skip
-        continue
+    elif filename.startswith(AUFS_WHITEOUT):
+      filename = filename[AUFS_WHITEOUT_PREFIX_LENGTH:]
+      removed_prefix_collector.add(absolute)
+      continue
 
-      elif one_file.startswith(AUFS_WHITEOUT):
-        filename = one_file[AUFS_WHITEOUT_PREFIX_LENGTH:]
-        removed_prefix_collector.add(os.path.join(rel_root, filename))
-        continue
-
-      else:
-        yield os.path.join(rel_root, one_file)
+    else:
+      yield absolute
 
 
-def compute_removed(base_trie, removed_prefixes):
+def __compute_removed(base_trie, removed_prefixes):
   for prefix in removed_prefixes:
     for filename in base_trie.keys(prefix):
       yield filename
 
 
-def compute_added_changed(base_trie, delta_trie):
+def __compute_added_changed(base_trie, delta_trie):
   added = set()
   changed = set()
 
@@ -47,10 +49,27 @@ def compute_added_changed(base_trie, delta_trie):
   return added, changed
 
 
-def new_fs(base_trie, added, removed):
+def __new_fs(base_trie, added, removed):
   for filename in base_trie.keys():
     if filename not in removed:
       yield filename
 
   for filename in added:
-    yield filename
+    yield filename
+
+
+def empty_fs():
+  return marisa_trie.Trie()
+
+
+def compute_new_diffs_and_fs(base_trie, filename_source,
+                             removed_prefix_collector):
+  new_trie = marisa_trie.Trie(filename_source)
+  (new_added, new_changed) = __compute_added_changed(base_trie, new_trie)
+
+  new_removed = marisa_trie.Trie(__compute_removed(base_trie,
+                                                   removed_prefix_collector))
+
+  new_fs = marisa_trie.Trie(__new_fs(base_trie, new_added, new_removed))
+
+  return (new_fs, new_added, new_changed, new_removed.keys())