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

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 from compiled_file_system import Unicode
   6 from extensions_paths import (
   7     API_FEATURES, JSON_TEMPLATES, MANIFEST_FEATURES, PERMISSION_FEATURES)
   8 import features_utility
   9 from future import Gettable, Future
  10 from third_party.json_schema_compiler.json_parse import Parse
  11
  12
  13 def _AddPlatformsFromDependencies(feature,
  14                                   api_features,
  15                                   manifest_features,
  16                                   permission_features):
  17   features_map = {
  18     'api': api_features,
  19     'manifest': manifest_features,
  20     'permission': permission_features,
  21   }
  22   dependencies = feature.get('dependencies')
  23   if dependencies is None:
  24     return ['apps', 'extensions']
  25   platforms = set()
  26   for dependency in dependencies:
  27     dep_type, dep_name = dependency.split(':')
  28     dependency_features = features_map[dep_type]
  29     dependency_feature = dependency_features.get(dep_name)
  30     # If the dependency can't be resolved, it is inaccessible and therefore
  31     # so is this feature.
  32     if dependency_feature is None:
  33       return []
  34     platforms = platforms.union(dependency_feature['platforms'])
  35   feature['platforms'] = list(platforms)
  36
  37
  38 class _FeaturesCache(object):
  39   def __init__(self, file_system, compiled_fs_factory, *json_paths):
  40     self._cache = compiled_fs_factory.Create(
  41         file_system, self._CreateCache, type(self))
  42     self._text_cache = compiled_fs_factory.ForUnicode(file_system)
  43     self._json_path = json_paths[0]
  44     self._extra_paths = json_paths[1:]
  45
  46   @Unicode
  47   def _CreateCache(self, _, features_json):
  48     extra_path_futures = [self._text_cache.GetFromFile(path)
  49                           for path in self._extra_paths]
  50     features = features_utility.Parse(Parse(features_json))
  51     for path_future in extra_path_futures:
  52       extra_json = path_future.Get()
  53       features = features_utility.MergedWith(
  54           features_utility.Parse(Parse(extra_json)), features)
  55     return features
  56
  57   def GetFeatures(self):
  58     if self._json_path is None:
  59       return Future(value={})
  60     return self._cache.GetFromFile(self._json_path)
  61
  62
  63 class FeaturesBundle(object):
  64   '''Provides access to properties of API, Manifest, and Permission features.
  65   '''
  66   def __init__(self, file_system, compiled_fs_factory, object_store_creator):
  67     self._api_cache = _FeaturesCache(
  68         file_system,
  69         compiled_fs_factory,
  70         API_FEATURES)
  71     self._manifest_cache = _FeaturesCache(
  72         file_system,
  73         compiled_fs_factory,
  74         MANIFEST_FEATURES,
  75         '%s/manifest.json' % JSON_TEMPLATES)
  76     self._permission_cache = _FeaturesCache(
  77         file_system,
  78         compiled_fs_factory,
  79         PERMISSION_FEATURES,
  80         '%s/permissions.json' % JSON_TEMPLATES)
  81     self._object_store = object_store_creator.Create(_FeaturesCache, 'features')
  82
  83   def GetPermissionFeatures(self):
  84     return self._permission_cache.GetFeatures()
  85
  86   def GetManifestFeatures(self):
  87     return self._manifest_cache.GetFeatures()
  88
  89   def GetAPIFeatures(self):
  90     api_features = self._object_store.Get('api_features').Get()
  91     if api_features is not None:
  92       return Future(value=api_features)
  93
  94     api_features_future = self._api_cache.GetFeatures()
  95     manifest_features_future = self._manifest_cache.GetFeatures()
  96     permission_features_future = self._permission_cache.GetFeatures()
  97     def resolve():
  98       api_features = api_features_future.Get()
  99       manifest_features = manifest_features_future.Get()
 100       permission_features = permission_features_future.Get()
 101       # TODO(rockot): Handle inter-API dependencies more gracefully.
 102       # Not yet a problem because there is only one such case (windows -> tabs).
 103       # If we don't store this value before annotating platforms, inter-API
 104       # dependencies will lead to infinite recursion.
 105       for feature in api_features.itervalues():
 106         _AddPlatformsFromDependencies(
 107             feature, api_features, manifest_features, permission_features)
 108       self._object_store.Set('api_features', api_features)
 109       return api_features
 110     return Future(delegate=Gettable(resolve))