Devserver: allow SubversionFileSystem to be pinned to a specific rev on construction

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 os
 
 class FileNotFoundError(Exception):
   def __init__(self, filename):
     Exception.__init__(self, filename)
 
 class StatInfo(object):
   '''The result of calling Stat on a FileSystem.
   '''
   def __init__(self, version, child_versions=None):
     self.version = version
     self.child_versions = child_versions
 
   def __eq__(self, other):
-    return (self.version == other.version and
+    return (isinstance(other, StatInfo) and
+            self.version == other.version and
             self.child_versions == other.child_versions)
 
   def __ne__(self, other):
     return not (self == other)
 
   def __str__(self):
     return '{version: %s, child_versions: %s}' % (self.version,
                                                   self.child_versions)
 
   def __repr__(self):
     return str(self)
 
 def ToUnicode(data):
   '''Returns the str |data| as a unicode object. It's expected to be utf8, but
   there are also latin-1 encodings in there for some reason. Fall back to that.
   '''
   try:
     return unicode(data, 'utf-8')
   except:
     return unicode(data, 'latin-1')
 
 class FileSystem(object):
   '''A FileSystem interface that can read files and directories.
   '''
-
   def Read(self, paths, binary=False):
     '''Reads each file in paths and returns a dictionary mapping the path to the
     contents. If a path in paths ends with a '/', it is assumed to be a
     directory, and a list of files in the directory is mapped to the path.
 
     If binary=False, the contents of each file will be unicode parsed as utf-8,
     and failing that as latin-1 (some extension docs use latin-1). If
     binary=True then the contents will be a str.
     '''
     raise NotImplementedError()
@@ skipping 12 matching lines @@
     raise NotImplementedError()
 
   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.
     '''
     raise NotImplementedError()