summaryrefslogtreecommitdiff
path: root/src/leap/mail/imap/messages.py
blob: 0356600ad473d3e4470292f36a48dcfc1187d809 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
# -*- coding: utf-8 -*-
# messages.py
# Copyright (C) 2013 LEAP
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
"""
LeapMessage and MessageCollection.
"""
import copy
import logging
import re
import threading
import StringIO

from collections import defaultdict
from email import message_from_string
from functools import partial

from pycryptopp.hash import sha256
from twisted.mail import imap4
from twisted.internet import defer
from zope.interface import implements
from zope.proxy import sameProxiedObjects

from leap.common.check import leap_assert, leap_assert_type
from leap.common.decorators import memoized_method
from leap.common.mail import get_email_charset
from leap.mail import walk
from leap.mail.utils import first, find_charset, lowerdict, empty
from leap.mail.utils import stringify_parts_map
from leap.mail.decorators import deferred_to_thread
from leap.mail.imap.index import IndexedDB
from leap.mail.imap.fields import fields, WithMsgFields
from leap.mail.imap.memorystore import MessageWrapper
from leap.mail.imap.messageparts import MessagePart, MessagePartDoc
from leap.mail.imap.parser import MBoxParser

logger = logging.getLogger(__name__)

# TODO ------------------------------------------------------------

# [ ] Add ref to incoming message during add_msg
# [ ] Add linked-from info.
#     * Need a new type of documents: linkage info.
#     * HDOCS are linked from FDOCs (ref to chash)
#     * CDOCS are linked from HDOCS (ref to chash)

# [ ] Delete incoming mail only after successful write!
# [ ] Remove UID from syncable db. Store only those indexes locally.

MSGID_PATTERN = r"""<([\w@.]+)>"""
MSGID_RE = re.compile(MSGID_PATTERN)


def try_unique_query(curried):
    """
    Try to execute a query that is expected to have a
    single outcome, and log a warning if more than one document found.

    :param curried: a curried function
    :type curried: callable
    """
    leap_assert(callable(curried), "A callable is expected")
    try:
        query = curried()
        if query:
            if len(query) > 1:
                # TODO we could take action, like trigger a background
                # process to kill dupes.
                name = getattr(curried, 'expected', 'doc')
                logger.warning(
                    "More than one %s found for this mbox, "
                    "we got a duplicate!!" % (name,))
            return query.pop()
        else:
            return None
    except Exception as exc:
        logger.exception("Unhandled error %r" % exc)


"""
A dictionary that keeps one lock per mbox and uid.
"""
# XXX too much overhead?
fdoc_locks = defaultdict(lambda: defaultdict(lambda: threading.Lock()))


class LeapMessage(fields, MBoxParser):
    """
    The main representation of a message.

    It indexes the messages in one mailbox by a combination
    of uid+mailbox name.
    """

    # TODO this has to change.
    # Should index primarily by chash, and keep a local-only
    # UID table.

    implements(imap4.IMessage)

    def __init__(self, soledad, uid, mbox, collection=None, container=None):
        """
        Initializes a LeapMessage.

        :param soledad: a Soledad instance
        :type soledad: Soledad
        :param uid: the UID for the message.
        :type uid: int or basestring
        :param mbox: the mbox this message belongs to
        :type mbox: str or unicode
        :param collection: a reference to the parent collection object
        :type collection: MessageCollection
        :param container: a IMessageContainer implementor instance
        :type container: IMessageContainer
        """
        self._soledad = soledad
        self._uid = int(uid) if uid is not None else None
        self._mbox = self._parse_mailbox_name(mbox)
        self._collection = collection
        self._container = container

        self.__chash = None
        self.__bdoc = None

        from twisted.internet import reactor
        self.reactor = reactor

    # XXX make these properties public

    @property
    def fdoc(self):
        """
        An accessor to the flags document.
        """
        if all(map(bool, (self._uid, self._mbox))):
            fdoc = None
            if self._container is not None:
                fdoc = self._container.fdoc
            if not fdoc:
                fdoc = self._get_flags_doc()
            if fdoc:
                fdoc_content = fdoc.content
                self.__chash = fdoc_content.get(
                    fields.CONTENT_HASH_KEY, None)
            return fdoc

    @property
    def hdoc(self):
        """
        An accessor to the headers document.
        """
        container = self._container
        if container is not None:
            hdoc = self._container.hdoc
            if hdoc and not empty(hdoc.content):
                return hdoc
        hdoc = self._get_headers_doc()

        if container and not empty(hdoc.content):
            # mem-cache it
            hdoc_content = hdoc.content
            chash = hdoc_content.get(fields.CONTENT_HASH_KEY)
            hdocs = {chash: hdoc_content}
            container.memstore.load_header_docs(hdocs)
        return hdoc

    @property
    def chash(self):
        """
        An accessor to the content hash for this message.
        """
        if not self.fdoc:
            return None
        if not self.__chash and self.fdoc:
            self.__chash = self.fdoc.content.get(
                fields.CONTENT_HASH_KEY, None)
        return self.__chash

    @property
    def bdoc(self):
        """
        An accessor to the body document.
        """
        if not self.hdoc:
            return None
        if not self.__bdoc:
            self.__bdoc = self._get_body_doc()
        return self.__bdoc

    # IMessage implementation

    def getUID(self):
        """
        Retrieve the unique identifier associated with this Message.

        :return: uid for this message
        :rtype: int
        """
        return self._uid

    def getFlags(self):
        """
        Retrieve the flags associated with this Message.

        :return: The flags, represented as strings
        :rtype: tuple
        """
        uid = self._uid

        flags = set([])
        fdoc = self.fdoc
        if fdoc:
            flags = set(fdoc.content.get(self.FLAGS_KEY, None))

        msgcol = self._collection

        # We treat the recent flag specially: gotten from
        # a mailbox-level document.
        if msgcol and uid in msgcol.recent_flags:
            flags.add(fields.RECENT_FLAG)
        if flags:
            flags = map(str, flags)
        return tuple(flags)

    # setFlags not in the interface spec but we use it with store command.

    def setFlags(self, flags, mode):
        """
        Sets the flags for this message

        :param flags: the flags to update in the message.
        :type flags: tuple of str
        :param mode: the mode for setting. 1 is append, -1 is remove, 0 set.
        :type mode: int
        """
        leap_assert(isinstance(flags, tuple), "flags need to be a tuple")
        mbox, uid = self._mbox, self._uid

        APPEND = 1
        REMOVE = -1
        SET = 0

        with fdoc_locks[mbox][uid]:
            doc = self.fdoc
            if not doc:
                logger.warning(
                    "Could not find FDOC for %r:%s while setting flags!" %
                    (mbox, uid))
                return
            current = doc.content[self.FLAGS_KEY]
            if mode == APPEND:
                newflags = tuple(set(tuple(current) + flags))
            elif mode == REMOVE:
                newflags = tuple(set(current).difference(set(flags)))
            elif mode == SET:
                newflags = flags
            new_fdoc = {
                self.FLAGS_KEY: newflags,
                self.SEEN_KEY: self.SEEN_FLAG in newflags,
                self.DEL_KEY: self.DELETED_FLAG in newflags}
            self._collection.memstore.update_flags(mbox, uid, new_fdoc)

        return map(str, newflags)

    def getInternalDate(self):
        """
        Retrieve the date internally associated with this message

        According to the spec, this is NOT the date and time in the
        RFC-822 header, but rather a date and time that reflects when the
        message was received.

        * In SMTP, date and time of final delivery.
        * In COPY, internal date/time of the source message.
        * In APPEND, date/time specified.

        :return: An RFC822-formatted date string.
        :rtype: str
        """
        date = self.hdoc.content.get(fields.DATE_KEY, '')
        return date

    #
    # IMessagePart
    #

    # XXX we should implement this interface too for the subparts
    # so we allow nested parts...

    def getBodyFile(self):
        """
        Retrieve a file object containing only the body of this message.

        :return: file-like object opened for reading
        :rtype: StringIO
        """
        def write_fd(body):
            fd.write(body)
            fd.seek(0)
            return fd

        # TODO refactor with getBodyFile in MessagePart

        fd = StringIO.StringIO()

        if self.bdoc is not None:
            bdoc_content = self.bdoc.content
            if empty(bdoc_content):
                logger.warning("No BDOC content found for message!!!")
                return write_fd("")

            body = bdoc_content.get(self.RAW_KEY, "")
            content_type = bdoc_content.get('content-type', "")
            charset = find_charset(content_type)
            if charset is None:
                charset = self._get_charset(body)
            try:
                if isinstance(body, unicode):
                    body = body.encode(charset)
            except UnicodeError as exc:
                logger.error(
                    "Unicode error, using 'replace'. {0!r}".format(exc))
                logger.debug("Attempted to encode with: %s" % charset)
                body = body.encode(charset, 'replace')
            finally:
                return write_fd(body)

        # We are still returning funky characters from here.
        else:
            logger.warning("No BDOC found for message.")
            return write_fd("")

    @memoized_method
    def _get_charset(self, stuff):
        """
        Gets (guesses?) the charset of a payload.

        :param stuff: the stuff to guess about.
        :type stuff: basestring
        :returns: charset
        """
        # XXX shouldn't we make the scope
        # of the decorator somewhat more persistent?
        # ah! yes! and put memory bounds.
        return get_email_charset(stuff)

    def getSize(self):
        """
        Return the total size, in octets, of this message.

        :return: size of the message, in octets
        :rtype: int
        """
        size = None
        if self.fdoc is not None:
            fdoc_content = self.fdoc.content
            size = fdoc_content.get(self.SIZE_KEY, False)
        else:
            logger.warning("No FLAGS doc for %s:%s" % (self._mbox,
                                                       self._uid))
        if not size:
            # XXX fallback, should remove when all migrated.
            size = self.getBodyFile().len
        return size

    def getHeaders(self, negate, *names):
        """
        Retrieve a group of message headers.

        :param names: The names of the headers to retrieve or omit.
        :type names: tuple of str

        :param negate: If True, indicates that the headers listed in names
                       should be omitted from the return value, rather
                       than included.
        :type negate: bool

        :return: A mapping of header field names to header field values
        :rtype: dict
        """
        # TODO split in smaller methods
        # XXX refactor together with MessagePart method

        headers = self._get_headers()
        if not headers:
            logger.warning("No headers found")
            return {str('content-type'): str('')}

        names = map(lambda s: s.upper(), names)
        if negate:
            cond = lambda key: key.upper() not in names
        else:
            cond = lambda key: key.upper() in names

        if isinstance(headers, list):
            headers = dict(headers)

        # default to most likely standard
        charset = find_charset(headers, "utf-8")
        headers2 = dict()
        for key, value in headers.items():
            # twisted imap server expects *some* headers to be lowercase
            # We could use a CaseInsensitiveDict here...
            if key.lower() == "content-type":
                key = key.lower()

            if not isinstance(key, str):
                key = key.encode(charset, 'replace')
            if not isinstance(value, str):
                value = value.encode(charset, 'replace')

            if value.endswith(";"):
                # bastards
                value = value[:-1]

            # filter original dict by negate-condition
            if cond(key):
                headers2[key] = value
        return headers2

    def _get_headers(self):
        """
        Return the headers dict for this message.
        """
        if self.hdoc is not None:
            hdoc_content = self.hdoc.content
            headers = hdoc_content.get(self.HEADERS_KEY, {})
            return headers

        else:
            logger.warning(
                "No HEADERS doc for msg %s:%s" % (
                    self._mbox,
                    self._uid))

    def isMultipart(self):
        """
        Return True if this message is multipart.
        """
        if self.fdoc:
            fdoc_content = self.fdoc.content
            is_multipart = fdoc_content.get(self.MULTIPART_KEY, False)
            return is_multipart
        else:
            logger.warning(
                "No FLAGS doc for msg %s:%s" % (
                    self._mbox,
                    self._uid))

    def getSubPart(self, part):
        """
        Retrieve a MIME submessage

        :type part: C{int}
        :param part: The number of the part to retrieve, indexed from 0.
        :raise IndexError: Raised if the specified part does not exist.
        :raise TypeError: Raised if this message is not multipart.
        :rtype: Any object implementing C{IMessagePart}.
        :return: The specified sub-part.
        """
        if not self.isMultipart():
            raise TypeError
        try:
            pmap_dict = self._get_part_from_parts_map(part + 1)
        except KeyError:
            raise IndexError
        return MessagePart(self._soledad, pmap_dict)

    #
    # accessors
    #

    def _get_part_from_parts_map(self, part):
        """
        Get a part map from the headers doc

        :raises: KeyError if key does not exist
        :rtype: dict
        """
        if not self.hdoc:
            logger.warning("Tried to get part but no HDOC found!")
            return None

        hdoc_content = self.hdoc.content
        pmap = hdoc_content.get(fields.PARTS_MAP_KEY, {})

        # remember, lads, soledad is using strings in its keys,
        # not integers!
        return pmap[str(part)]

    # XXX moved to memory store
    # move the rest too. ------------------------------------------
    def _get_flags_doc(self):
        """
        Return the document that keeps the flags for this
        message.
        """
        result = {}
        try:
            flag_docs = self._soledad.get_from_index(
                fields.TYPE_MBOX_UID_IDX,
                fields.TYPE_FLAGS_VAL, self._mbox, str(self._uid))
            result = first(flag_docs)
        except Exception as exc:
            # ugh! Something's broken down there!
            logger.warning("ERROR while getting flags for UID: %s" % self._uid)
            logger.exception(exc)
        finally:
            return result

    # TODO move to soledadstore instead of accessing soledad directly
    def _get_headers_doc(self):
        """
        Return the document that keeps the headers for this
        message.
        """
        head_docs = self._soledad.get_from_index(
            fields.TYPE_C_HASH_IDX,
            fields.TYPE_HEADERS_VAL, str(self.chash))
        return first(head_docs)

    # TODO move to soledadstore instead of accessing soledad directly
    def _get_body_doc(self):
        """
        Return the document that keeps the body for this
        message.
        """
        hdoc_content = self.hdoc.content
        body_phash = hdoc_content.get(
            fields.BODY_KEY, None)
        if not body_phash:
            logger.warning("No body phash for this document!")
            return None

        # XXX get from memstore too...
        # if memstore: memstore.get_phrash
        # memstore should keep a dict with weakrefs to the
        # phash doc...

        if self._container is not None:
            bdoc = self._container.memstore.get_cdoc_from_phash(body_phash)
            if not empty(bdoc) and not empty(bdoc.content):
                return bdoc

        # no memstore, or no body doc found there
        if self._soledad:
            body_docs = self._soledad.get_from_index(
                fields.TYPE_P_HASH_IDX,
                fields.TYPE_CONTENT_VAL, str(body_phash))
            return first(body_docs)
        else:
            logger.error("No phash in container, and no soledad found!")

    def __getitem__(self, key):
        """
        Return an item from the content of the flags document,
        for convenience.

        :param key: The key
        :type key: str

        :return: The content value indexed by C{key} or None
        :rtype: str
        """
        return self.fdoc.content.get(key, None)

    def does_exist(self):
        """
        Return True if there is actually a flags document for this
        UID and mbox.
        """
        return not empty(self.fdoc)


class MessageCollection(WithMsgFields, IndexedDB, MBoxParser):
    """
    A collection of messages, surprisingly.

    It is tied to a selected mailbox name that is passed to its constructor.
    Implements a filter query over the messages contained in a soledad
    database.
    """

    # XXX this should be able to produce a MessageSet methinks
    # could validate these kinds of objects turning them
    # into a template for the class.
    FLAGS_DOC = "FLAGS"
    HEADERS_DOC = "HEADERS"
    CONTENT_DOC = "CONTENT"
    """
    RECENT_DOC is a document that stores a list of the UIDs
    with the recent flag for this mailbox. It deserves a special treatment
    because:
    (1) it cannot be set by the user
    (2) it's a flag that we set inmediately after a fetch, which is quite
        often.
    (3) we need to be able to set/unset it in batches without doing a single
        write for each element in the sequence.
    """
    RECENT_DOC = "RECENT"
    """
    HDOCS_SET_DOC is a document that stores a set of the Document-IDs
    (the u1db index) for all the headers documents for a given mailbox.
    We use it to prefetch massively all the headers for a mailbox.
    This is the second massive query, after fetching all the FLAGS,  that
    a MUA will do in a case where we do not have local disk cache.
    """
    HDOCS_SET_DOC = "HDOCS_SET"

    templates = {

        # Message Level

        FLAGS_DOC: {
            fields.TYPE_KEY: fields.TYPE_FLAGS_VAL,
            fields.UID_KEY: 1,  # XXX moe to a local table
            fields.MBOX_KEY: fields.INBOX_VAL,
            fields.CONTENT_HASH_KEY: "",

            fields.SEEN_KEY: False,
            fields.DEL_KEY: False,
            fields.FLAGS_KEY: [],
            fields.MULTIPART_KEY: False,
            fields.SIZE_KEY: 0
        },

        HEADERS_DOC: {
            fields.TYPE_KEY: fields.TYPE_HEADERS_VAL,
            fields.CONTENT_HASH_KEY: "",

            fields.DATE_KEY: "",
            fields.SUBJECT_KEY: "",

            fields.HEADERS_KEY: {},
            fields.PARTS_MAP_KEY: {},
        },

        CONTENT_DOC: {
            fields.TYPE_KEY: fields.TYPE_CONTENT_VAL,
            fields.PAYLOAD_HASH_KEY: "",
            fields.LINKED_FROM_KEY: [],
            fields.CTYPE_KEY: "",  # should index by this too

            # should only get inmutable headers parts
            # (for indexing)
            fields.HEADERS_KEY: {},
            fields.RAW_KEY: "",
            fields.PARTS_MAP_KEY: {},
            fields.HEADERS_KEY: {},
            fields.MULTIPART_KEY: False,
        },

        # Mailbox Level

        RECENT_DOC: {
            fields.TYPE_KEY: fields.TYPE_RECENT_VAL,
            fields.MBOX_KEY: fields.INBOX_VAL,
            fields.RECENTFLAGS_KEY: [],
        },

        HDOCS_SET_DOC: {
            fields.TYPE_KEY: fields.TYPE_HDOCS_SET_VAL,
            fields.MBOX_KEY: fields.INBOX_VAL,
            fields.HDOCS_SET_KEY: [],
        }


    }

    # Different locks for wrapping both the u1db document getting/setting
    # and the property getting/settting in an atomic operation.

    # TODO we would abstract this to a SoledadProperty class

    _rdoc_lock = defaultdict(lambda: threading.Lock())
    _rdoc_write_lock = defaultdict(lambda: threading.Lock())
    _rdoc_read_lock = defaultdict(lambda: threading.Lock())
    _rdoc_property_lock = defaultdict(lambda: threading.Lock())

    _initialized = {}

    def __init__(self, mbox=None, soledad=None, memstore=None):
        """
        Constructor for MessageCollection.

        On initialization, we ensure that we have a document for
        storing the recent flags. The nature of this flag make us wanting
        to store the set of the UIDs with this flag at the level of the
        MessageCollection for each mailbox, instead of treating them
        as a property of each message.

        We are passed an instance of MemoryStore, the same for the
        SoledadBackedAccount, that we use as a read cache and a buffer
        for writes.

        :param mbox: the name of the mailbox. It is the name
                     with which we filter the query over the
                     messages database.
        :type mbox: str
        :param soledad: Soledad database
        :type soledad: Soledad instance
        :param memstore: a MemoryStore instance
        :type memstore: MemoryStore
        """
        leap_assert(mbox, "Need a mailbox name to initialize")
        leap_assert(mbox.strip() != "", "mbox cannot be blank space")
        leap_assert(isinstance(mbox, (str, unicode)),
                    "mbox needs to be a string")
        leap_assert(soledad, "Need a soledad instance to initialize")

        # okay, all in order, keep going...

        self.mbox = self._parse_mailbox_name(mbox)

        # XXX get a SoledadStore passed instead
        self._soledad = soledad
        self.memstore = memstore

        self.__rflags = None

        if not self._initialized.get(mbox, False):
            try:
                self.initialize_db()
                # ensure that we have a recent-flags doc
                self._get_or_create_rdoc()
            except Exception:
                logger.debug("Error initializing %r" % (mbox,))
            else:
                self._initialized[mbox] = True

        from twisted.internet import reactor
        self.reactor = reactor

    def _get_empty_doc(self, _type=FLAGS_DOC):
        """
        Returns an empty doc for storing different message parts.
        Defaults to returning a template for a flags document.
        :return: a dict with the template
        :rtype: dict
        """
        if _type not in self.templates.keys():
            raise TypeError("Improper type passed to _get_empty_doc")
        return copy.deepcopy(self.templates[_type])

    def _get_or_create_rdoc(self):
        """
        Try to retrieve the recent-flags doc for this MessageCollection,
        and create one if not found.
        """
        # XXX should move this to memstore too
        with self._rdoc_write_lock[self.mbox]:
            rdoc = self._get_recent_doc_from_soledad()
            if rdoc is None:
                rdoc = self._get_empty_doc(self.RECENT_DOC)
                if self.mbox != fields.INBOX_VAL:
                    rdoc[fields.MBOX_KEY] = self.mbox
                self._soledad.create_doc(rdoc)

    @deferred_to_thread
    def _do_parse(self, raw):
        """
        Parse raw message and return it along with
        relevant information about its outer level.

        This is done in a separate thread, and the callback is passed
        to `_do_add_msg` method.

        :param raw: the raw message
        :type raw: StringIO or basestring
        :return: msg, parts, chash, size, multi
        :rtype: tuple
        """
        msg = message_from_string(raw)
        parts = walk.get_parts(msg)
        size = len(raw)
        chash = sha256.SHA256(raw).hexdigest()
        multi = msg.is_multipart()
        return msg, parts, chash, size, multi

    def _populate_flags(self, flags, uid, chash, size, multi):
        """
        Return a flags doc.

        XXX Missing DOC -----------
        """
        fd = self._get_empty_doc(self.FLAGS_DOC)

        fd[self.MBOX_KEY] = self.mbox
        fd[self.UID_KEY] = uid
        fd[self.CONTENT_HASH_KEY] = chash
        fd[self.SIZE_KEY] = size
        fd[self.MULTIPART_KEY] = multi
        if flags:
            fd[self.FLAGS_KEY] = flags
            fd[self.SEEN_KEY] = self.SEEN_FLAG in flags
            fd[self.DEL_KEY] = self.DELETED_FLAG in flags
            fd[self.RECENT_KEY] = True  # set always by default
        return fd

    def _populate_headr(self, msg, chash, subject, date):
        """
        Return a headers doc.

        XXX Missing DOC -----------
        """
        headers = defaultdict(list)
        for k, v in msg.items():
            headers[k].append(v)

        # "fix" for repeated headers.
        for k, v in headers.items():
            newline = "\n%s: " % (k,)
            headers[k] = newline.join(v)

        lower_headers = lowerdict(headers)
        msgid = first(MSGID_RE.findall(
            lower_headers.get('message-id', '')))

        hd = self._get_empty_doc(self.HEADERS_DOC)
        hd[self.CONTENT_HASH_KEY] = chash
        hd[self.HEADERS_KEY] = headers
        hd[self.MSGID_KEY] = msgid

        if not subject and self.SUBJECT_FIELD in headers:
            hd[self.SUBJECT_KEY] = headers[self.SUBJECT_FIELD]
        else:
            hd[self.SUBJECT_KEY] = subject

        if not date and self.DATE_FIELD in headers:
            hd[self.DATE_KEY] = headers[self.DATE_FIELD]
        else:
            hd[self.DATE_KEY] = date
        return hd

    def _fdoc_already_exists(self, chash):
        """
        Check whether we can find a flags doc for this mailbox with the
        given content-hash. It enforces that we can only have the same maessage
        listed once for a a given mailbox.

        :param chash: the content-hash to check about.
        :type chash: basestring
        :return: False, if it does not exist, or UID.
        """
        exist = False
        exist = self.memstore.get_fdoc_from_chash(chash, self.mbox)

        if not exist:
            exist = self._get_fdoc_from_chash(chash)
        if exist and exist.content is not None:
            return exist.content.get(fields.UID_KEY, "unknown-uid")
        else:
            return False

    def add_msg(self, raw, subject=None, flags=None, date=None,
                notify_on_disk=False):
        """
        Creates a new message document.

        :param raw: the raw message
        :type raw: str

        :param subject: subject of the message.
        :type subject: str

        :param flags: flags
        :type flags: list

        :param date: the received date for the message
        :type date: str

        :return: a deferred that will be fired with the message
                 uid when the adding succeed.
        :rtype: deferred
        """
        if flags is None:
            flags = tuple()
        leap_assert_type(flags, tuple)

        observer = defer.Deferred()
        d = self._do_parse(raw)
        d.addCallback(lambda result: self.reactor.callInThread(
            self._do_add_msg, result, flags, subject, date,
            notify_on_disk, observer))
        return observer

    # Called in thread
    def _do_add_msg(self, parse_result, flags, subject,
                    date, notify_on_disk, observer):
        """
        Helper that creates a new message document.
        Here lives the magic of the leap mail. Well, in soledad, really.

        See `add_msg` docstring for parameter info.

        :param parse_result: a tuple with the results of `self._do_parse`
        :type parse_result: tuple
        :param observer: a deferred that will be fired with the message
                         uid when the adding succeed.
        :type observer: deferred
        """
        # TODO signal that we can delete the original message!-----
        # when all the processing is done.

        # TODO add the linked-from info !
        # TODO add reference to the original message

        msg, parts, chash, size, multi = parse_result

        # check for uniqueness --------------------------------
        # Watch out! We're reserving a UID right after this!
        existing_uid = self._fdoc_already_exists(chash)
        if existing_uid:
            msg = self.get_msg_by_uid(existing_uid)

            # We can say the observer that we're done
            self.reactor.callFromThread(observer.callback, existing_uid)
            msg.setFlags((fields.DELETED_FLAG,), -1)
            return

        # XXX get FUCKING UID from autoincremental table
        uid = self.memstore.increment_last_soledad_uid(self.mbox)

        # We can say the observer that we're done at this point, but
        # before that we should make sure it has no serious consequences
        # if we're issued, for instance, a fetch command right after...
        # self.reactor.callFromThread(observer.callback, uid)
        # if we did the notify, we need to invalidate the deferred
        # so not to try to fire it twice.
        # observer = None

        fd = self._populate_flags(flags, uid, chash, size, multi)
        hd = self._populate_headr(msg, chash, subject, date)

        body_phash_fun = [walk.get_body_phash_simple,
                          walk.get_body_phash_multi][int(multi)]
        body_phash = body_phash_fun(walk.get_payloads(msg))
        parts_map = walk.walk_msg_tree(parts, body_phash=body_phash)

        # add parts map to header doc
        # (body, multi, part_map)
        for key in parts_map:
            hd[key] = parts_map[key]
        del parts_map

        hd = stringify_parts_map(hd)

        # The MessageContainer expects a dict, one-indexed
        cdocs = dict(enumerate(walk.get_raw_docs(msg, parts), 1))

        self.set_recent_flag(uid)
        msg_container = MessageWrapper(fd, hd, cdocs)
        self.memstore.create_message(
            self.mbox, uid, msg_container,
            observer=observer, notify_on_disk=notify_on_disk)

    #
    # getters: specific queries
    #

    # recent flags

    def _get_recent_flags(self):
        """
        An accessor for the recent-flags set for this mailbox.
        """
        # XXX check if we should remove this
        if self.__rflags is not None:
            return self.__rflags

        if self.memstore is not None:
            with self._rdoc_lock[self.mbox]:
                rflags = self.memstore.get_recent_flags(self.mbox)
                if not rflags:
                    # not loaded in the memory store yet.
                    # let's fetch them from soledad...
                    rdoc = self._get_recent_doc_from_soledad()
                    if rdoc is None:
                        return set([])
                    rflags = set(rdoc.content.get(
                        fields.RECENTFLAGS_KEY, []))
                    # ...and cache them now.
                    self.memstore.load_recent_flags(
                        self.mbox,
                        {'doc_id': rdoc.doc_id, 'set': rflags})
            return rflags

    def _set_recent_flags(self, value):
        """
        Setter for the recent-flags set for this mailbox.
        """
        if self.memstore is not None:
            self.memstore.set_recent_flags(self.mbox, value)

    recent_flags = property(
        _get_recent_flags, _set_recent_flags,
        doc="Set of UIDs with the recent flag for this mailbox.")

    def _get_recent_doc_from_soledad(self):
        """
        Get recent-flags document from Soledad for this mailbox.
        :rtype: SoledadDocument or None
        """
        curried = partial(
            self._soledad.get_from_index,
            fields.TYPE_MBOX_IDX,
            fields.TYPE_RECENT_VAL, self.mbox)
        curried.expected = "rdoc"
        with self._rdoc_read_lock[self.mbox]:
            return try_unique_query(curried)

    # Property-set modification (protected by a different
    # lock to give atomicity to the read/write operation)

    def unset_recent_flags(self, uids):
        """
        Unset Recent flag for a sequence of uids.

        :param uids: the uids to unset
        :type uid: sequence
        """
        with self._rdoc_property_lock[self.mbox]:
            self.recent_flags.difference_update(
                set(uids))

    # Individual flags operations

    def unset_recent_flag(self, uid):
        """
        Unset Recent flag for a given uid.

        :param uid: the uid to unset
        :type uid: int
        """
        with self._rdoc_property_lock[self.mbox]:
            self.recent_flags.difference_update(
                set([uid]))

    @deferred_to_thread
    def set_recent_flag(self, uid):
        """
        Set Recent flag for a given uid.

        :param uid: the uid to set
        :type uid: int
        """
        with self._rdoc_property_lock[self.mbox]:
            self.recent_flags = self.recent_flags.union(
                set([uid]))

    # individual doc getters, message layer.

    def _get_fdoc_from_chash(self, chash):
        """
        Return a flags document for this mailbox with a given chash.

        :return: A SoledadDocument containing the Flags Document, or None if
                 the query failed.
        :rtype: SoledadDocument or None.
        """
        curried = partial(
            self._soledad.get_from_index,
            fields.TYPE_MBOX_C_HASH_IDX,
            fields.TYPE_FLAGS_VAL, self.mbox, chash)
        curried.expected = "fdoc"
        fdoc = try_unique_query(curried)
        if fdoc is not None:
            return fdoc
        else:
            # probably this should be the other way round,
            # ie, try fist on memstore...
            cf = self.memstore._chash_fdoc_store
            fdoc = cf[chash][self.mbox]
            # hey, I just needed to wrap fdoc thing into
            # a "content" attribute, look a better way...
            if not empty(fdoc):
                return MessagePartDoc(
                    new=None, dirty=None, part=None,
                    store=None, doc_id=None,
                    content=fdoc)

    def _get_uid_from_msgidCb(self, msgid):
        hdoc = None
        curried = partial(
            self._soledad.get_from_index,
            fields.TYPE_MSGID_IDX,
            fields.TYPE_HEADERS_VAL, msgid)
        curried.expected = "hdoc"
        hdoc = try_unique_query(curried)

        # XXX this is only a quick hack to avoid regression
        # on the "multiple copies of the draft" issue, but
        # this is currently broken since  it's not efficient to
        # look for this. Should lookup better.
        # FIXME!

        if hdoc is not None:
            hdoc_dict = hdoc.content

        else:
            hdocstore = self.memstore._hdoc_store
            match = [x for _, x in hdocstore.items() if x['msgid'] == msgid]
            hdoc_dict = first(match)

        if hdoc_dict is None:
            logger.warning("Could not find hdoc for msgid %s"
                           % (msgid,))
            return None
        msg_chash = hdoc_dict.get(fields.CONTENT_HASH_KEY)

        fdoc = self._get_fdoc_from_chash(msg_chash)
        if not fdoc:
            logger.warning("Could not find fdoc for msgid %s"
                           % (msgid,))
            return None
        return fdoc.content.get(fields.UID_KEY, None)

    @deferred_to_thread
    def _get_uid_from_msgid(self, msgid):
        """
        Return a UID for a given message-id.

        It first gets the headers-doc for that msg-id, and
        it found it queries the flags doc for the current mailbox
        for the matching content-hash.

        :return: A UID, or None
        """
        # We need to wait a little bit, cause in some of the cases
        # the query is received right after we've saved the document,
        # and we cannot find it otherwise. This seems to be enough.

        # XXX do a deferLater instead ??
        # XXX is this working?
        return self._get_uid_from_msgidCb(msgid)

    @deferred_to_thread
    def set_flags(self, mbox, messages, flags, mode, observer):
        """
        Set flags for a sequence of messages.

        :param mbox: the mbox this message belongs to
        :type mbox: str or unicode
        :param messages: the messages to iterate through
        :type messages: sequence
        :flags: the flags to be set
        :type flags: tuple
        :param mode: the mode for setting. 1 is append, -1 is remove, 0 set.
        :type mode: int
        :param observer: a deferred that will be called with the dictionary
                         mapping UIDs to flags after the operation has been
                         done.
        :type observer: deferred
        """
        reactor = self.reactor
        getmsg = self.get_msg_by_uid

        def set_flags(uid, flags, mode):
            msg = getmsg(uid, mem_only=True, flags_only=True)
            if msg is not None:
                return uid, msg.setFlags(flags, mode)

        setted_flags = [set_flags(uid, flags, mode) for uid in messages]
        result = dict(filter(None, setted_flags))

        reactor.callFromThread(observer.callback, result)

    # getters: generic for a mailbox

    def get_msg_by_uid(self, uid, mem_only=False, flags_only=False):
        """
        Retrieves a LeapMessage by UID.
        This is used primarity in the Mailbox fetch and store methods.

        :param uid: the message uid to query by
        :type uid: int
        :param mem_only: a flag that indicates whether this Message should
                         pass a reference to soledad to retrieve missing pieces
                         or not.
        :type mem_only: bool
        :param flags_only: whether the message should carry only a reference
                           to the flags document.
        :type flags_only: bool

        :return: A LeapMessage instance matching the query,
                 or None if not found.
        :rtype: LeapMessage
        """
        msg_container = self.memstore.get_message(
            self.mbox, uid, flags_only=flags_only)

        if msg_container is not None:
            if mem_only:
                msg = LeapMessage(None, uid, self.mbox, collection=self,
                                  container=msg_container)
            else:
                # We pass a reference to soledad just to be able to retrieve
                # missing parts that cannot be found in the container, like
                # the content docs after a copy.
                msg = LeapMessage(self._soledad, uid, self.mbox,
                                  collection=self, container=msg_container)
        else:
            msg = LeapMessage(self._soledad, uid, self.mbox, collection=self)

        if not msg.does_exist():
            return None
        return msg

    def get_all_docs(self, _type=fields.TYPE_FLAGS_VAL):
        """
        Get all documents for the selected mailbox of the
        passed type. By default, it returns the flag docs.

        If you want acess to the content, use __iter__ instead

        :return: a list of u1db documents
        :rtype: list of SoledadDocument
        """
        if _type not in fields.__dict__.values():
            raise TypeError("Wrong type passed to get_all_docs")

        if sameProxiedObjects(self._soledad, None):
            logger.warning('Tried to get messages but soledad is None!')
            return []

        all_docs = [doc for doc in self._soledad.get_from_index(
            fields.TYPE_MBOX_IDX,
            _type, self.mbox)]

        # inneficient, but first let's grok it and then
        # let's worry about efficiency.
        # XXX FIXINDEX -- should implement order by in soledad
        # FIXME ----------------------------------------------
        return sorted(all_docs, key=lambda item: item.content['uid'])

    def all_soledad_uid_iter(self):
        """
        Return an iterator through the UIDs of all messages, sorted in
        ascending order.
        """
        db_uids = set([doc.content[self.UID_KEY] for doc in
                       self._soledad.get_from_index(
                           fields.TYPE_MBOX_IDX,
                           fields.TYPE_FLAGS_VAL, self.mbox)
                       if not empty(doc)])
        return db_uids

    def all_uid_iter(self):
        """
        Return an iterator through the UIDs of all messages, from memory.
        """
        mem_uids = self.memstore.get_uids(self.mbox)
        soledad_known_uids = self.memstore.get_soledad_known_uids(
            self.mbox)
        combined = tuple(set(mem_uids).union(soledad_known_uids))
        return combined

    def get_all_soledad_flag_docs(self):
        """
        Return a dict with the content of all the flag documents
        in soledad store for the given mbox.

        :param mbox: the mailbox
        :type mbox: str or unicode
        :rtype: dict
        """
        # XXX we really could return a reduced version with
        # just {'uid': (flags-tuple,) since the prefetch is
        # only oriented to get the flag tuples.
        all_docs = [(
            doc.content[self.UID_KEY],
            dict(doc.content))
            for doc in
            self._soledad.get_from_index(
                fields.TYPE_MBOX_IDX,
                fields.TYPE_FLAGS_VAL, self.mbox)
            if not empty(doc.content)]
        all_flags = dict(all_docs)
        return all_flags

    def all_headers(self):
        """
        Return a dict with all the header documents for this
        mailbox.

        :rtype: dict
        """
        return self.memstore.all_headers(self.mbox)

    def count(self):
        """
        Return the count of messages for this mailbox.

        :rtype: int
        """
        return self.memstore.count(self.mbox)

    # unseen messages

    def unseen_iter(self):
        """
        Get an iterator for the message UIDs with no `seen` flag
        for this mailbox.

        :return: iterator through unseen message doc UIDs
        :rtype: iterable
        """
        return self.memstore.unseen_iter(self.mbox)

    def count_unseen(self):
        """
        Count all messages with the `Unseen` flag.

        :returns: count
        :rtype: int
        """
        return len(list(self.unseen_iter()))

    def get_unseen(self):
        """
        Get all messages with the `Unseen` flag

        :returns: a list of LeapMessages
        :rtype: list
        """
        return [LeapMessage(self._soledad, docid, self.mbox, collection=self)
                for docid in self.unseen_iter()]

    # recent messages

    # XXX take it from memstore
    def count_recent(self):
        """
        Count all messages with the `Recent` flag.
        It just retrieves the length of the recent_flags set,
        which is stored in a specific type of document for
        this collection.

        :returns: count
        :rtype: int
        """
        return len(self.recent_flags)

    def __len__(self):
        """
        Returns the number of messages on this mailbox.

        :rtype: int
        """
        return self.count()

    def __iter__(self):
        """
        Returns an iterator over all messages.

        :returns: iterator of dicts with content for all messages.
        :rtype: iterable
        """
        return (LeapMessage(self._soledad, docuid, self.mbox, collection=self)
                for docuid in self.all_uid_iter())

    def __repr__(self):
        """
        Representation string for this object.
        """
        return u"<MessageCollection: mbox '%s' (%s)>" % (
            self.mbox, self.count())

    # XXX should implement __eq__ also !!!
    # use chash...