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 file_system import FileSystem, FileNotFoundError 6 from future import Future 7 8 9 class OfflineFileSystem(FileSystem): 10 '''An offline FileSystem which masquerades as another file system. It throws 11 FileNotFound error for all operations, and overrides GetIdentity. 12 ''' 13 def __init__(self, fs): 14 self._fs = fs 15 16 def Read(self, paths, skip_not_found=False): 17 if skip_not_found: return Future(value={}) 18 def raise_file_not_found(): 19 raise FileNotFoundError('File system is offline, cannot read %s' % paths) 20 return Future(callback=raise_file_not_found) 21 22 def Stat(self, path): 23 raise FileNotFoundError('File system is offline, cannot read %s' % path) 24 25 def GetIdentity(self): 26 return self._fs.GetIdentity() 27
