docker-offlineimap/offlineimap/repository/LocalStatus.py
Sebastian Spaeth 1b54b85f20 Reuse LocalStatus() folders rather than recreate instances
If we ask twice for a LocalStatusFolder via getfolder(), we would
get a newly created instance each time. This can lead to problems,
as e.g. write locks protecting files only work within the same Folder
instance. Make it so, that we cache all Folder instances that we have
asked for and hand back the existing one if we ask again for it,
rather than recreate a new instance.

Also, make getfolders() a noop for LocalStatus. We attempted to
derive the foldername from the name of the LocalStatusfile. However,
this is not really possible, as we do file name mangling
(".$" -> "dot", "/" -> ".") and there is no way to get the original folder
name from the LocalStatus file name anyway.

This commit could potentially solve the "file not found" errors, that people
have been seeing with their LocalStatusCache files. If we have 2
instances of a LocalStatusFolder pointing to the same file, our locking
system would not work.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
2012-09-01 01:19:19 +02:00

106 lines
4.0 KiB
Python

# Local status cache repository support
# Copyright (C) 2002 John Goerzen
# <jgoerzen@complete.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
from offlineimap.folder.LocalStatus import LocalStatusFolder, magicline
from offlineimap.folder.LocalStatusSQLite import LocalStatusSQLiteFolder
from offlineimap.repository.Base import BaseRepository
import os
import re
class LocalStatusRepository(BaseRepository):
def __init__(self, reposname, account):
BaseRepository.__init__(self, reposname, account)
# Root directory in which the LocalStatus folders reside
self.root = os.path.join(account.getaccountmeta(), 'LocalStatus')
# statusbackend can be 'plain' or 'sqlite'
backend = self.account.getconf('status_backend', 'plain')
if backend == 'sqlite':
self._backend = 'sqlite'
self.LocalStatusFolderClass = LocalStatusSQLiteFolder
self.root += '-sqlite'
elif backend == 'plain':
self._backend = 'plain'
self.LocalStatusFolderClass = LocalStatusFolder
else:
raise SyntaxWarning("Unknown status_backend '%s' for account '%s'" \
% (backend, account.name))
if not os.path.exists(self.root):
os.mkdir(self.root, 0o700)
# self._folders is a dict of name:LocalStatusFolders()
self._folders = {}
def getsep(self):
return '.'
def getfolderfilename(self, foldername):
"""Return the full path of the status file
This mimics the path that Folder().getfolderbasename() would return"""
if not foldername:
basename = '.'
else: #avoid directory hierarchies and file names such as '/'
basename = foldername.replace('/', '.')
# replace with literal 'dot' if final path name is '.' as '.' is
# an invalid file name.
basename = re.sub('(^|\/)\.$','\\1dot', basename)
return os.path.join(self.root, basename)
def makefolder(self, foldername):
"""Create a LocalStatus Folder
Empty Folder for plain backend. NoOp for sqlite backend as those
are created on demand."""
if self._backend == 'sqlite':
return # noop for sqlite which creates on-demand
if self.account.dryrun:
return # bail out in dry-run mode
filename = self.getfolderfilename(foldername)
file = open(filename + ".tmp", "wt")
file.write(magicline + '\n')
file.close()
os.rename(filename + ".tmp", filename)
# Invalidate the cache.
self._folders = None
def getfolder(self, foldername):
"""Return the Folder() object for a foldername"""
if foldername in self._folders:
return self._folders[foldername]
folder = self.LocalStatusFolderClass(foldername, self)
self._folders[foldername] = folder
return folder
def getfolders(self):
"""Returns a list of all cached folders.
Does nothing for this backend. We mangle the folder file names
(see getfolderfilename) so we can not derive folder names from
the file names that we have available. TODO: need to store a
list of folder names somehow?"""
pass
def forgetfolders(self):
"""Forgets the cached list of folders, if any. Useful to run
after a sync run."""
self._folders = {}