docker-offlineimap/offlineimap/folder/UIDMaps.py
Sebastian Spaeth ca012d3a81 Implement more efficient functions for the MappedUID case
We are calling getmessagelist() internally a lot, e.g. just to check if
a UID exists (from uidexist()). This is a very expensive operation in
the UIDMapped case, as we reconstruct the whole messagelist dict every
single time, involving lots of copying etc.

So we provide more efficient implementations for the uidexists()
getmessageuidlist() and getmessagecount() functions that are fast in the
UIDMapped case. This should solve the performance regression that was
recently observed in the Mapped UID case.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>
Reviewed-and-tested-by: Vincent Beffara <vbeffara@ens-lyon.fr>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>
2011-03-28 17:52:22 +02:00

255 lines
9.3 KiB
Python

# Base folder 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 threading import *
from IMAP import IMAPFolder
import os.path
class MappingFolderMixIn:
"""Helper class to map between Folder() instances where both side assign a uid
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 _initmapping(self):
self.maplock = Lock()
(self.diskr2l, self.diskl2r) = self._loadmaps()
self._mb = self.__class__.__bases__[1]
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
line = line.strip()
(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):
return [mapping[x] for x in items]
def cachemessagelist(self):
self._mb.cachemessagelist(self)
reallist = self._mb.getmessagelist(self)
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 reallist.has_key(luid):
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 self.l2r.has_key(luid):
ruid = nextneg
nextneg -= 1
self.l2r[luid] = ruid
self.r2l[ruid] = luid
finally:
self.maplock.release()
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
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()
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)
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)
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()
def getmessage(self, uid):
"""Returns the content of the specified message."""
return self._mb.getmessage(self, self.r2l[uid])
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.
"""
# 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(self, -1, content, flags, rtime)
if newluid < 1:
raise ValueError("Backend could not find uid for message")
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()
def getmessageflags(self, uid):
return self._mb.getmessageflags(self, self.r2l[uid])
def getmessagetime(self, uid):
return None
def savemessageflags(self, uid, flags):
self._mb.savemessageflags(self, self.r2l[uid], flags)
def addmessageflags(self, uid, flags):
self._mb.addmessageflags(self, self.r2l[uid], flags)
def addmessagesflags(self, uidlist, flags):
self._mb.addmessagesflags(self, self._uidlist(self.r2l, uidlist),
flags)
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()
def deletemessageflags(self, uid, flags):
self._mb.deletemessageflags(self, self.r2l[uid], flags)
def deletemessagesflags(self, uidlist, flags):
self._mb.deletemessagesflags(self, self._uidlist(self.r2l, uidlist),
flags)
def deletemessage(self, uid):
self._mb.deletemessage(self, self.r2l[uid])
self._mapped_delete([uid])
def deletemessages(self, uidlist):
self._mb.deletemessages(self, self._uidlist(self.r2l, uidlist))
self._mapped_delete(uidlist)
#def syncmessagesto_neguid_msg(self, uid, dest, applyto, register = 1):
# does not need changes because it calls functions that make the changes
# same goes for all other sync messages types.
# Define a class for local part of IMAP.
class MappedIMAPFolder(MappingFolderMixIn, IMAPFolder):
def __init__(self, *args, **kwargs):
IMAPFolder.__init__(self, *args, **kwargs)
self._initmapping()