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# 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.
import posixpath
from docs_server_utils import StringIdentity
from file_system import FileSystem
from future import Future
class ChrootFileSystem(FileSystem):
'''ChrootFileSystem(fs, path) exposes a FileSystem whose root is |path| inside
|fs|, so ChrootFileSystem(fs, 'hello').Read(['world']) is equivalent to
fs.Read(['hello/world']) with the 'hello' prefix stripped from the result.
'''
def __init__(self, file_system, root):
'''Parameters:
|file_system| The FileSystem instance to transpose paths of.
|root| The path to transpose all Read/Stat calls by.
'''
self._file_system = file_system
self._root = root.strip('/')
def Read(self, paths, skip_not_found=False):
# Maintain reverse mapping so the result can be mapped to the original
# paths given (the result from |file_system| will include |root| in the
# result, which would be wrong).
prefixed_paths = {}
def prefix(path):
prefixed = posixpath.join(self._root, path)
prefixed_paths[prefixed] = path
return prefixed
future_result = self._file_system.Read(
tuple(prefix(path) for path in paths),
skip_not_found=skip_not_found)
def resolve():
return dict((prefixed_paths[path], content)
for path, content in future_result.Get().iteritems())
return Future(callback=resolve)
def Refresh(self):
return self._file_system.Refresh()
def Stat(self, path):
return self._file_system.Stat(posixpath.join(self._root, path))
def GetIdentity(self):
return StringIdentity(
'%s/%s' % (self._file_system.GetIdentity(), self._root))
def __repr__(self):
return 'ChrootFileSystem(%s, %s)' % (
self._root, repr(self._file_system))
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