Docserver: Automatically implement FileSystem.Stat if FileSystem.StatAsync has

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

 # Copyright (c) 2012 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.
 
 import posixpath
 import traceback
 
 from future import Future
 from path_util import (
     AssertIsDirectory, AssertIsValid, IsDirectory, IsValid, SplitParent,
@@ skipping 103 matching lines @@
                                                      handle)
 
   def Refresh(self):
     '''Asynchronously refreshes the content of the FileSystem, returning a
     future to its completion.
     '''
     raise NotImplementedError(self.__class__)
 
   # TODO(cduvall): Allow Stat to take a list of paths like Read.
   def Stat(self, path):
-    '''Returns a |StatInfo| object containing the version of |path|. If |path|
+    '''DEPRECATED: Please try to use StatAsync instead.
+
+    Returns a |StatInfo| object containing the version of |path|. If |path|
     is a directory, |StatInfo| will have the versions of all the children of
     the directory in |StatInfo.child_versions|.
 
     If the path cannot be found, raises a FileNotFoundError.
     For any other failure, raises a FileSystemError.
     '''
+    # Delegate to this implementation's StatAsync if it has been implemented.
+    if type(self).StatAsync != FileSystem.StatAsync:
+      return self.StatAsync(path).Get()
     raise NotImplementedError(self.__class__)
 
   def StatAsync(self, path):
-    '''Bandaid for a lack of an async Stat function. Stat() should be async
-    by default but for now just let implementations override this if they like.
+    '''An async version of Stat. Returns a Future to a StatInfo rather than a
+    raw StatInfo.
+
+    This is a bandaid for a lack of an async Stat function. Stat() should be
+    async by default but for now just let implementations override this if they
+    like.
     '''
     return Future(callback=lambda: self.Stat(path))
 
   def GetIdentity(self):
     '''The identity of the file system, exposed for caching classes to
     namespace their caches. this will usually depend on the configuration of
     that file system - e.g. a LocalFileSystem with a base path of /var is
     different to that of a SubversionFileSystem with a base path of /bar, is
     different to a LocalFileSystem with a base path of /usr.
     '''
@@ skipping 39 matching lines @@
             self.GetIdentity() == other.GetIdentity())
 
   def __ne__(self, other):
     return not (self == other)
 
   def __repr__(self):
     return '<%s>' % type(self).__name__
 
   def __str__(self):
     return repr(self)