chrome/common/extensions/docs/server2/chroot_file_system.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 import posixpath
   6
   7 from docs_server_utils import StringIdentity
   8 from file_system import FileSystem
   9 from future import Future
  10
  11
  12 class ChrootFileSystem(FileSystem):
  13   '''ChrootFileSystem(fs, path) exposes a FileSystem whose root is |path| inside
  14   |fs|, so ChrootFileSystem(fs, 'hello').Read(['world']) is equivalent to
  15   fs.Read(['hello/world']) with the 'hello' prefix stripped from the result.
  16   '''
  17
  18   def __init__(self, file_system, root):
  19     '''Parameters:
  20     |file_system| The FileSystem instance to transpose paths of.
  21     |root|        The path to transpose all Read/Stat calls by.
  22     '''
  23     self._file_system = file_system
  24     self._root = root.strip('/')
  25
  26   def Read(self, paths, skip_not_found=False):
  27     # Maintain reverse mapping so the result can be mapped to the original
  28     # paths given (the result from |file_system| will include |root| in the
  29     # result, which would be wrong).
  30     prefixed_paths = {}
  31     def prefix(path):
  32       prefixed = posixpath.join(self._root, path)
  33       prefixed_paths[prefixed] = path
  34       return prefixed
  35     def next(results):
  36       return dict((prefixed_paths[path], content)
  37                   for path, content in results.iteritems())
  38     return self._file_system.Read(tuple(prefix(path) for path in paths),
  39                                   skip_not_found-skip_not_found).Then(next)
  40
  41   def Refresh(self):
  42     return self._file_system.Refresh()
  43
  44   def Stat(self, path):
  45     return self._file_system.Stat(posixpath.join(self._root, path))
  46
  47   def GetIdentity(self):
  48     return StringIdentity(
  49         '%s/%s' % (self._file_system.GetIdentity(), self._root))
  50
  51   def __repr__(self):
  52     return 'ChrootFileSystem(%s, %s)' % (
  53             self._root, repr(self._file_system))