Docserver manifest follow up (rewrite)

chrome/common/extensions/docs/server2/features_utility.py

+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from copy import deepcopy
+
+def Parse(features_json):
+  '''Standardize the raw features file json |features_json| into a more regular
+  format. Return a dictionary of features, keyed by name. Each feature is
+  guaranteed to have a 'name' attribute and a 'platforms' attribute that is a
+  list of platforms the feature is relevant to. Valid platforms are 'app' or
+  'extension'. Other optional keys may be present in each feature.
+
+  Features with a 'whitelist' are only relevant to apps or extensions on that
+  whitelist and are not included in the retured features dictionary.
+  '''
+  features = {}
+
+  for name, value in features_json.iteritems():
+    # Some feature names corrispond to a list; force a list down to a single
+    # feature by removing entries that have a 'whitelist'.
+    if isinstance(value, list):
+      values = [subvalue for subvalue in value if not 'whitelist' in subvalue]
+      if values:
+        value = values[0]
+      else:
+        continue
+
+    if 'whitelist' in value:
+      continue
+
+    features[name] = { 'platforms': [] }
+
+    platforms = value.pop('extension_types')
+    if platforms == 'all' or 'platform_app' in platforms:
+      features[name]['platforms'].append('app')
+    if platforms == 'all' or 'extension' in platforms:
+      features[name]['platforms'].append('extension')
+
+    features[name]['name'] = name
+    features[name].update(value)
+
+  return features
+
+def Filtered(features, platform=None):
+  '''Create a new features dictionary from |features| that contains only items
+  relevant to |platform|. Items retained are deepcopied. Returns new features
+  dictionary.
+  '''
+  filtered_features = {}
+
+  for name, feature in features.iteritems():
+    if not platform or platform in feature['platforms']:
+      filtered_features[name] = deepcopy(feature)
+
+  return filtered_features
+
+def MergedWith(features, other):
+  '''Merge |features| with an additional dictionary to create a new features
+  dictionary. If a feature is common to both |features| and |other|, then it is
+  merged using the standard dictionary update instead of being overwritten.
+  Returns the new features dictionary.
+  '''
+  for key, value in other.iteritems():
+    if key in features:
+      features[key].update(value)
+    else:
+      features[key] = value
+
+  return features