Docserver: Pull knowledge of host file systems into a single

chrome/common/extensions/docs/server2/availability_finder.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 collections import Mapping
 import os
 
 from api_schema_graph import APISchemaGraph
 from branch_utility import BranchUtility
 from compiled_file_system import CompiledFileSystem
@@ skipping 211 matching lines @@
     return availability
 
   def GetApiNodeAvailability(self, api_name):
     '''Returns an APISchemaGraph annotated with each node's availability (the
     ChannelInfo at the oldest channel it's available in).
     '''
     availability_graph = self._node_level_object_store.Get(api_name).Get()
     if availability_graph is not None:
       return availability_graph
 
-
     availability_graph = APISchemaGraph()
     trunk_graph = APISchemaGraph(_GetApiSchema(api_name,
                                                self._host_file_system))
     def update_availability_graph(file_system, channel_info):
       version_graph = APISchemaGraph(_GetApiSchema(api_name, file_system))
       # Keep track of any new schema elements from this version by adding
       # them to |availability_graph|.
       #
       # Calling |availability_graph|.Lookup() on the nodes being updated
       # will return the |annotation| object.
       availability_graph.Update(version_graph.Subtract(availability_graph),
                                 annotation=channel_info)
 
       # Continue looping until there are no longer differences between this
       # version and trunk.
       return trunk_graph != version_graph
 
     self._file_system_iterator.Ascending(self.GetApiAvailability(api_name),
                                          update_availability_graph)
 
     self._node_level_object_store.Set(api_name, availability_graph)
     return availability_graph