docker-offlineimap/offlineimap/folder/UIDMaps.py
Eygene Ryabinkin e7fabf9e57 Properly re-raise exception to save original tracebacks
We usually mutate some exceptions to OfflineImapError() and it is
a whole lot better if such exception will show up with the original
traceback, so all valid occurrences of such mutations were transformed
to the 3-tuple form of "raise".  Had also added coding guidelines
document where this re-raise strategy is documented.

Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>
2015-01-12 17:51:21 +03:00

315 lines
12 KiB
Python

# Base folder support
# Copyright (C) 2002-2015 John Goerzen & contributors
#
# 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 sys import exc_info
from threading import Lock
from offlineimap import OfflineImapError
from .IMAP import IMAPFolder
import os.path
class MappedIMAPFolder(IMAPFolder):
"""IMAP class to map between Folder() instances where both side assign a uid
This Folder is used on the local side, while the remote side should
be an IMAPFolder.
Instance variables (self.):
r2l: dict mapping message uids: self.r2l[remoteuid]=localuid
l2r: dict mapping message uids: self.r2l[localuid]=remoteuid
#TODO: what is the difference, how are they used?
diskr2l: dict mapping message uids: self.r2l[remoteuid]=localuid
diskl2r: dict mapping message uids: self.r2l[localuid]=remoteuid"""
def __init__(self, *args, **kwargs):
IMAPFolder.__init__(self, *args, **kwargs)
self.maplock = Lock()
(self.diskr2l, self.diskl2r) = self._loadmaps()
self._mb = IMAPFolder(*args, **kwargs)
"""Representing the local IMAP Folder using local UIDs"""
def _getmapfilename(self):
return os.path.join(self.repository.getmapdir(),
self.getfolderbasename())
def _loadmaps(self):
self.maplock.acquire()
try:
mapfilename = self._getmapfilename()
if not os.path.exists(mapfilename):
return ({}, {})
file = open(mapfilename, 'rt')
r2l = {}
l2r = {}
while 1:
line = file.readline()
if not len(line):
break
try:
line = line.strip()
except ValueError:
raise Exception("Corrupt line '%s' in UID mapping file '%s'"%
(line, mapfilename)), None, exc_info()[2]
(str1, str2) = line.split(':')
loc = long(str1)
rem = long(str2)
r2l[rem] = loc
l2r[loc] = rem
return (r2l, l2r)
finally:
self.maplock.release()
def _savemaps(self, dolock = 1):
mapfilename = self._getmapfilename()
if dolock: self.maplock.acquire()
try:
file = open(mapfilename + ".tmp", 'wt')
for (key, value) in self.diskl2r.iteritems():
file.write("%d:%d\n" % (key, value))
file.close()
os.rename(mapfilename + '.tmp', mapfilename)
finally:
if dolock: self.maplock.release()
def _uidlist(self, mapping, items):
try:
return [mapping[x] for x in items]
except KeyError as e:
raise OfflineImapError("Could not find UID for msg '{0}' (f:'{1}'."
" This is usually a bad thing and should be reported on the ma"
"iling list.".format(e.args[0], self),
OfflineImapError.ERROR.MESSAGE), None, exc_info()[2]
# Interface from BaseFolder
def cachemessagelist(self):
self._mb.cachemessagelist()
reallist = self._mb.getmessagelist()
self.maplock.acquire()
try:
# OK. Now we've got a nice list. First, delete things from the
# summary that have been deleted from the folder.
for luid in self.diskl2r.keys():
if not luid in reallist:
ruid = self.diskl2r[luid]
del self.diskr2l[ruid]
del self.diskl2r[luid]
# Now, assign negative UIDs to local items.
self._savemaps(dolock = 0)
nextneg = -1
self.r2l = self.diskr2l.copy()
self.l2r = self.diskl2r.copy()
for luid in reallist.keys():
if not luid in self.l2r:
ruid = nextneg
nextneg -= 1
self.l2r[luid] = ruid
self.r2l[ruid] = luid
finally:
self.maplock.release()
# Interface from BaseFolder
def uidexists(self, ruid):
"""Checks if the (remote) UID exists in this Folder"""
# This implementation overrides the one in BaseFolder, as it is
# much more efficient for the mapped case.
return ruid in self.r2l
# Interface from BaseFolder
def getmessageuidlist(self):
"""Gets a list of (remote) UIDs.
You may have to call cachemessagelist() before calling this function!"""
# This implementation overrides the one in BaseFolder, as it is
# much more efficient for the mapped case.
return self.r2l.keys()
# Interface from BaseFolder
def getmessagecount(self):
"""Gets the number of messages in this folder.
You may have to call cachemessagelist() before calling this function!"""
# This implementation overrides the one in BaseFolder, as it is
# much more efficient for the mapped case.
return len(self.r2l)
# Interface from BaseFolder
def getmessagelist(self):
"""Gets the current message list. This function's implementation
is quite expensive for the mapped UID case. You must call
cachemessagelist() before calling this function!"""
retval = {}
localhash = self._mb.getmessagelist()
self.maplock.acquire()
try:
for key, value in localhash.items():
try:
key = self.l2r[key]
except KeyError:
# Sometimes, the IMAP backend may put in a new message,
# then this function acquires the lock before the system
# has the chance to note it in the mapping. In that case,
# just ignore it.
continue
value = value.copy()
value['uid'] = self.l2r[value['uid']]
retval[key] = value
return retval
finally:
self.maplock.release()
# Interface from BaseFolder
def getmessage(self, uid):
"""Returns the content of the specified message."""
return self._mb.getmessage(self.r2l[uid])
# Interface from BaseFolder
def savemessage(self, uid, content, flags, rtime):
"""Writes a new message, with the specified uid.
The UIDMaps class will not return a newly assigned uid, as it
internally maps different uids between IMAP servers. So a
successful savemessage() invocation will return the same uid it
has been invoked with. As it maps between 2 IMAP servers which
means the source message must already have an uid, it requires a
positive uid to be passed in. Passing in a message with a
negative uid will do nothing and return the negative uid.
If the uid is > 0, the backend should set the uid to this, if it can.
If it cannot set the uid to that, it will save it anyway.
It will return the uid assigned in any case.
See folder/Base for details. Note that savemessage() does not
check against dryrun settings, so you need to ensure that
savemessage is never called in a dryrun mode.
"""
self.ui.savemessage('imap', uid, flags, self)
# Mapped UID instances require the source to already have a
# positive UID, so simply return here.
if uid < 0:
return uid
#if msg uid already exists, just modify the flags
if uid in self.r2l:
self.savemessageflags(uid, flags)
return uid
newluid = self._mb.savemessage(-1, content, flags, rtime)
if newluid < 1:
raise ValueError("Backend could not find uid for message, returned "
"%s" % newluid)
self.maplock.acquire()
try:
self.diskl2r[newluid] = uid
self.diskr2l[uid] = newluid
self.l2r[newluid] = uid
self.r2l[uid] = newluid
self._savemaps(dolock = 0)
finally:
self.maplock.release()
return uid
# Interface from BaseFolder
def getmessageflags(self, uid):
return self._mb.getmessageflags(self.r2l[uid])
# Interface from BaseFolder
def getmessagetime(self, uid):
return None
# Interface from BaseFolder
def savemessageflags(self, uid, flags):
"""
Note that this function does not check against dryrun settings,
so you need to ensure that it is never called in a
dryrun mode."""
self._mb.savemessageflags(self.r2l[uid], flags)
# Interface from BaseFolder
def addmessageflags(self, uid, flags):
self._mb.addmessageflags(self.r2l[uid], flags)
# Interface from BaseFolder
def addmessagesflags(self, uidlist, flags):
self._mb.addmessagesflags(self._uidlist(self.r2l, uidlist),
flags)
# Interface from BaseFolder
def change_message_uid(self, ruid, new_ruid):
"""Change the message from existing ruid to new_ruid
:param new_uid: The old remote UID will be changed to a new
UID. The UIDMaps case handles this efficiently by simply
changing the mappings file."""
if ruid not in self.r2l:
raise OfflineImapError("Cannot change unknown Maildir UID %s" % ruid,
OfflineImapError.ERROR.MESSAGE)
if ruid == new_ruid: return # sanity check shortcut
self.maplock.acquire()
try:
luid = self.r2l[ruid]
self.l2r[luid] = new_ruid
del self.r2l[ruid]
self.r2l[new_ruid] = luid
#TODO: diskl2r|r2l are a pain to sync and should be done away with
#diskl2r only contains positive UIDs, so wrap in ifs
if luid>0: self.diskl2r[luid] = new_ruid
if ruid>0: del self.diskr2l[ruid]
if new_ruid > 0: self.diskr2l[new_ruid] = luid
self._savemaps(dolock = 0)
finally:
self.maplock.release()
def _mapped_delete(self, uidlist):
self.maplock.acquire()
try:
needssave = 0
for ruid in uidlist:
luid = self.r2l[ruid]
del self.r2l[ruid]
del self.l2r[luid]
if ruid > 0:
del self.diskr2l[ruid]
del self.diskl2r[luid]
needssave = 1
if needssave:
self._savemaps(dolock = 0)
finally:
self.maplock.release()
# Interface from BaseFolder
def deletemessageflags(self, uid, flags):
self._mb.deletemessageflags(self.r2l[uid], flags)
# Interface from BaseFolder
def deletemessagesflags(self, uidlist, flags):
self._mb.deletemessagesflags(self._uidlist(self.r2l, uidlist),
flags)
# Interface from BaseFolder
def deletemessage(self, uid):
self._mb.deletemessage(self.r2l[uid])
self._mapped_delete([uid])
# Interface from BaseFolder
def deletemessages(self, uidlist):
self._mb.deletemessages(self._uidlist(self.r2l, uidlist))
self._mapped_delete(uidlist)