rebaseline_server: allow users to generate SKP diff patches on a shared instance

gm/rebaseline_server/results.py

 #!/usr/bin/python
 
 """
 Copyright 2013 Google Inc.
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 Repackage expected/actual GM results as needed by our HTML rebaseline viewer.
 """
@@ skipping 195 matching lines @@
       pattern: which files to read within root (fnmatch-style pattern)
 
     Returns:
       A meta-dictionary containing all the JSON dictionaries found within
       the directory tree, keyed by builder name (the basename of the directory
       where each JSON dictionary was found).
 
     Raises:
       IOError if root does not refer to an existing directory
     """
-    # I considered making this call _read_dicts_from_root(), but I decided
+    # I considered making this call read_dicts_from_root(), but I decided
     # it was better to prune out the ignored builders within the os.walk().
     if not os.path.isdir(root):
       raise IOError('no directory found at path %s' % root)
     meta_dict = {}
     for dirpath, _, filenames in os.walk(root):
       for matching_filename in fnmatch.filter(filenames, pattern):
         builder = os.path.basename(dirpath)
         if self._ignore_builder(builder):
           continue
         full_path = os.path.join(dirpath, matching_filename)
         meta_dict[builder] = gm_json.LoadFromFile(full_path)
     return meta_dict
 
-  def _read_dicts_from_root(self, root, pattern='*.json'):
+  @staticmethod
+  def read_dicts_from_root(root, pattern='*.json'):
     """Read all JSON dictionaries within a directory tree.
 
+    TODO(stephana): Factor this out into a utility module, as a standalone
+    function (not part of a class).
+
     Args:
       root: path to root of directory tree
       pattern: which files to read within root (fnmatch-style pattern)
 
     Returns:
       A meta-dictionary containing all the JSON dictionaries found within
       the directory tree, keyed by the pathname (relative to root) of each JSON
       dictionary.
 
     Raises:
@@ skipping 87 matching lines @@
       default_value: value to return if input_dict is None or any key cannot
           be found along the way
     """
     if input_dict == None:
       return default_value
     for key in keys:
       input_dict = input_dict.get(key, None)
       if input_dict == None:
         return default_value
     return input_dict