make compare_rendered_pictures process render_pictures's new JSON output format

gm/rebaseline_server/results.py

Index: gm/rebaseline_server/results.py
diff --git a/gm/rebaseline_server/results.py b/gm/rebaseline_server/results.py
index 255dfa31e2f7e55f1540f5e95b7bc200a196db2f..461e7463a6dd281d0ca16820d4070b4ce365107f 100755
--- a/gm/rebaseline_server/results.py
+++ b/gm/rebaseline_server/results.py
@@ -190,20 +190,25 @@ class BaseComparisons(object):
         return False
     return True
 
-  def _read_dicts_from_root(self, root, pattern='*.json'):
+  def _read_builder_dicts_from_root(self, root, pattern='*.json'):
     """Read all JSON dictionaries within a directory tree.
 
+    Skips any dictionaries belonging to a builder we have chosen to ignore.
+
     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 builder name of each dictionary.
+      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
+    # 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 = {}
@@ -212,8 +217,34 @@ class BaseComparisons(object):
         builder = os.path.basename(dirpath)
         if self._ignore_builder(builder):
           continue
-        fullpath = os.path.join(dirpath, matching_filename)
-        meta_dict[builder] = gm_json.LoadFromFile(fullpath)
+        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'):
+    """Read all JSON dictionaries within a directory tree.
+
+    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:
+      IOError if root does not refer to an existing directory
+    """
+    if not os.path.isdir(root):
+      raise IOError('no directory found at path %s' % root)
+    meta_dict = {}
+    for abs_dirpath, dirnames, filenames in os.walk(root):
+      rel_dirpath = os.path.relpath(abs_dirpath, root)
+      for matching_filename in fnmatch.filter(filenames, pattern):
+        abs_path = os.path.join(abs_dirpath, matching_filename)
+        rel_path = os.path.join(rel_dirpath, matching_filename)
+        meta_dict[rel_path] = gm_json.LoadFromFile(abs_path)
     return meta_dict
 
   @staticmethod
@@ -240,18 +271,18 @@ class BaseComparisons(object):
 
     Input:
       {
-        "failed" : {
-          "changed.png" : [ "bitmap-64bitMD5", 8891695120562235492 ],
+        KEY_A1 : {
+          KEY_B1 : VALUE_B1,
         },
-        "no-comparison" : {
-          "unchanged.png" : [ "bitmap-64bitMD5", 11092453015575919668 ],
+        KEY_A2 : {
+          KEY_B2 : VALUE_B2,
         }
       }
 
     Output:
       {
-        "changed.png" : [ "bitmap-64bitMD5", 8891695120562235492 ],
-        "unchanged.png" : [ "bitmap-64bitMD5", 11092453015575919668 ],
+        KEY_B1 : VALUE_B1,
+        KEY_B2 : VALUE_B2,
       }
 
     If this would result in any repeated keys, it will raise an Exception.
@@ -263,3 +294,13 @@ class BaseComparisons(object):
           raise Exception('duplicate key %s in combine_subdicts' % subdict_key)
         output_dict[subdict_key] = subdict_value
     return output_dict
+
+  @staticmethod
+  def get_multilevel(input_dict, *keys):
+    """ Returns input_dict[key1][key2][...], or None if any key is not found.
+    """
+    for key in keys:
+      if input_dict == None:
+        return None
+      input_dict = input_dict.get(key, None)
+    return input_dict