summary refs log tree commit diff
path: root/synapse/handlers/sync.py
blob: 91c6c6be3ca9819ab792437bf0d348745f5f35ec (plain) (blame)
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
# -*- coding: utf-8 -*-
# Copyright 2015 - 2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from synapse.api.constants import Membership, EventTypes
from synapse.util.async import concurrently_execute
from synapse.util.logcontext import LoggingContext
from synapse.util.metrics import Measure, measure_func
from synapse.util.caches.response_cache import ResponseCache
from synapse.push.clientformat import format_push_rules_for_user
from synapse.visibility import filter_events_for_client
from synapse.types import RoomStreamToken

from twisted.internet import defer

import collections
import logging
import itertools

logger = logging.getLogger(__name__)


SyncConfig = collections.namedtuple("SyncConfig", [
    "user",
    "filter_collection",
    "is_guest",
    "request_key",
    "device_id",
])


class TimelineBatch(collections.namedtuple("TimelineBatch", [
    "prev_batch",
    "events",
    "limited",
])):
    __slots__ = []

    def __nonzero__(self):
        """Make the result appear empty if there are no updates. This is used
        to tell if room needs to be part of the sync result.
        """
        return bool(self.events)


class JoinedSyncResult(collections.namedtuple("JoinedSyncResult", [
    "room_id",           # str
    "timeline",          # TimelineBatch
    "state",             # dict[(str, str), FrozenEvent]
    "ephemeral",
    "account_data",
    "unread_notifications",
])):
    __slots__ = []

    def __nonzero__(self):
        """Make the result appear empty if there are no updates. This is used
        to tell if room needs to be part of the sync result.
        """
        return bool(
            self.timeline
            or self.state
            or self.ephemeral
            or self.account_data
            # nb the notification count does not, er, count: if there's nothing
            # else in the result, we don't need to send it.
        )


class ArchivedSyncResult(collections.namedtuple("ArchivedSyncResult", [
    "room_id",            # str
    "timeline",           # TimelineBatch
    "state",              # dict[(str, str), FrozenEvent]
    "account_data",
])):
    __slots__ = []

    def __nonzero__(self):
        """Make the result appear empty if there are no updates. This is used
        to tell if room needs to be part of the sync result.
        """
        return bool(
            self.timeline
            or self.state
            or self.account_data
        )


class InvitedSyncResult(collections.namedtuple("InvitedSyncResult", [
    "room_id",   # str
    "invite",    # FrozenEvent: the invite event
])):
    __slots__ = []

    def __nonzero__(self):
        """Invited rooms should always be reported to the client"""
        return True


class SyncResult(collections.namedtuple("SyncResult", [
    "next_batch",  # Token for the next sync
    "presence",  # List of presence events for the user.
    "account_data",  # List of account_data events for the user.
    "joined",  # JoinedSyncResult for each joined room.
    "invited",  # InvitedSyncResult for each invited room.
    "archived",  # ArchivedSyncResult for each archived room.
    "to_device",  # List of direct messages for the device.
    "device_lists",  # List of user_ids whose devices have chanegd
    "device_one_time_keys_count",  # Dict of algorithm to count for one time keys
                                   # for this device
])):
    __slots__ = []

    def __nonzero__(self):
        """Make the result appear empty if there are no updates. This is used
        to tell if the notifier needs to wait for more events when polling for
        events.
        """
        return bool(
            self.presence or
            self.joined or
            self.invited or
            self.archived or
            self.account_data or
            self.to_device or
            self.device_lists
        )


class SyncHandler(object):

    def __init__(self, hs):
        self.store = hs.get_datastore()
        self.notifier = hs.get_notifier()
        self.presence_handler = hs.get_presence_handler()
        self.event_sources = hs.get_event_sources()
        self.clock = hs.get_clock()
        self.response_cache = ResponseCache(hs)
        self.state = hs.get_state_handler()

    def wait_for_sync_for_user(self, sync_config, since_token=None, timeout=0,
                               full_state=False):
        """Get the sync for a client if we have new data for it now. Otherwise
        wait for new data to arrive on the server. If the timeout expires, then
        return an empty sync result.
        Returns:
            A Deferred SyncResult.
        """
        result = self.response_cache.get(sync_config.request_key)
        if not result:
            result = self.response_cache.set(
                sync_config.request_key,
                self._wait_for_sync_for_user(
                    sync_config, since_token, timeout, full_state
                )
            )
        return result

    @defer.inlineCallbacks
    def _wait_for_sync_for_user(self, sync_config, since_token, timeout,
                                full_state):
        context = LoggingContext.current_context()
        if context:
            if since_token is None:
                context.tag = "initial_sync"
            elif full_state:
                context.tag = "full_state_sync"
            else:
                context.tag = "incremental_sync"

        if timeout == 0 or since_token is None or full_state:
            # we are going to return immediately, so don't bother calling
            # notifier.wait_for_events.
            result = yield self.current_sync_for_user(
                sync_config, since_token, full_state=full_state,
            )
            defer.returnValue(result)
        else:
            def current_sync_callback(before_token, after_token):
                return self.current_sync_for_user(sync_config, since_token)

            result = yield self.notifier.wait_for_events(
                sync_config.user.to_string(), timeout, current_sync_callback,
                from_token=since_token,
            )
            defer.returnValue(result)

    def current_sync_for_user(self, sync_config, since_token=None,
                              full_state=False):
        """Get the sync for client needed to match what the server has now.
        Returns:
            A Deferred SyncResult.
        """
        return self.generate_sync_result(sync_config, since_token, full_state)

    @defer.inlineCallbacks
    def push_rules_for_user(self, user):
        user_id = user.to_string()
        rules = yield self.store.get_push_rules_for_user(user_id)
        rules = format_push_rules_for_user(user, rules)
        defer.returnValue(rules)

    @defer.inlineCallbacks
    def ephemeral_by_room(self, sync_config, now_token, since_token=None):
        """Get the ephemeral events for each room the user is in
        Args:
            sync_config (SyncConfig): The flags, filters and user for the sync.
            now_token (StreamToken): Where the server is currently up to.
            since_token (StreamToken): Where the server was when the client
                last synced.
        Returns:
            A tuple of the now StreamToken, updated to reflect the which typing
            events are included, and a dict mapping from room_id to a list of
            typing events for that room.
        """

        with Measure(self.clock, "ephemeral_by_room"):
            typing_key = since_token.typing_key if since_token else "0"

            room_ids = yield self.store.get_rooms_for_user(sync_config.user.to_string())

            typing_source = self.event_sources.sources["typing"]
            typing, typing_key = yield typing_source.get_new_events(
                user=sync_config.user,
                from_key=typing_key,
                limit=sync_config.filter_collection.ephemeral_limit(),
                room_ids=room_ids,
                is_guest=sync_config.is_guest,
            )
            now_token = now_token.copy_and_replace("typing_key", typing_key)

            ephemeral_by_room = {}

            for event in typing:
                # we want to exclude the room_id from the event, but modifying the
                # result returned by the event source is poor form (it might cache
                # the object)
                room_id = event["room_id"]
                event_copy = {k: v for (k, v) in event.iteritems()
                              if k != "room_id"}
                ephemeral_by_room.setdefault(room_id, []).append(event_copy)

            receipt_key = since_token.receipt_key if since_token else "0"

            receipt_source = self.event_sources.sources["receipt"]
            receipts, receipt_key = yield receipt_source.get_new_events(
                user=sync_config.user,
                from_key=receipt_key,
                limit=sync_config.filter_collection.ephemeral_limit(),
                room_ids=room_ids,
                is_guest=sync_config.is_guest,
            )
            now_token = now_token.copy_and_replace("receipt_key", receipt_key)

            for event in receipts:
                room_id = event["room_id"]
                # exclude room id, as above
                event_copy = {k: v for (k, v) in event.iteritems()
                              if k != "room_id"}
                ephemeral_by_room.setdefault(room_id, []).append(event_copy)

        defer.returnValue((now_token, ephemeral_by_room))

    @defer.inlineCallbacks
    def _load_filtered_recents(self, room_id, sync_config, now_token,
                               since_token=None, recents=None, newly_joined_room=False):
        """
        Returns:
            a Deferred TimelineBatch
        """
        with Measure(self.clock, "load_filtered_recents"):
            timeline_limit = sync_config.filter_collection.timeline_limit()
            block_all_timeline = sync_config.filter_collection.blocks_all_room_timeline()

            if recents is None or newly_joined_room or timeline_limit < len(recents):
                limited = True
            else:
                limited = False

            if recents:
                recents = sync_config.filter_collection.filter_room_timeline(recents)
                recents = yield filter_events_for_client(
                    self.store,
                    sync_config.user.to_string(),
                    recents,
                )
            else:
                recents = []

            if not limited or block_all_timeline:
                defer.returnValue(TimelineBatch(
                    events=recents,
                    prev_batch=now_token,
                    limited=False
                ))

            filtering_factor = 2
            load_limit = max(timeline_limit * filtering_factor, 10)
            max_repeat = 5  # Only try a few times per room, otherwise
            room_key = now_token.room_key
            end_key = room_key

            since_key = None
            if since_token and not newly_joined_room:
                since_key = since_token.room_key

            while limited and len(recents) < timeline_limit and max_repeat:
                events, end_key = yield self.store.get_room_events_stream_for_room(
                    room_id,
                    limit=load_limit + 1,
                    from_key=since_key,
                    to_key=end_key,
                )
                loaded_recents = sync_config.filter_collection.filter_room_timeline(
                    events
                )
                loaded_recents = yield filter_events_for_client(
                    self.store,
                    sync_config.user.to_string(),
                    loaded_recents,
                )
                loaded_recents.extend(recents)
                recents = loaded_recents

                if len(events) <= load_limit:
                    limited = False
                    break
                max_repeat -= 1

            if len(recents) > timeline_limit:
                limited = True
                recents = recents[-timeline_limit:]
                room_key = recents[0].internal_metadata.before

            prev_batch_token = now_token.copy_and_replace(
                "room_key", room_key
            )

        defer.returnValue(TimelineBatch(
            events=recents,
            prev_batch=prev_batch_token,
            limited=limited or newly_joined_room
        ))

    @defer.inlineCallbacks
    def get_state_after_event(self, event):
        """
        Get the room state after the given event

        Args:
            event(synapse.events.EventBase): event of interest

        Returns:
            A Deferred map from ((type, state_key)->Event)
        """
        state_ids = yield self.store.get_state_ids_for_event(event.event_id)
        if event.is_state():
            state_ids = state_ids.copy()
            state_ids[(event.type, event.state_key)] = event.event_id
        defer.returnValue(state_ids)

    @defer.inlineCallbacks
    def get_state_at(self, room_id, stream_position):
        """ Get the room state at a particular stream position

        Args:
            room_id(str): room for which to get state
            stream_position(StreamToken): point at which to get state

        Returns:
            A Deferred map from ((type, state_key)->Event)
        """
        last_events, token = yield self.store.get_recent_events_for_room(
            room_id, end_token=stream_position.room_key, limit=1,
        )

        if last_events:
            last_event = last_events[-1]
            state = yield self.get_state_after_event(last_event)

        else:
            # no events in this room - so presumably no state
            state = {}
        defer.returnValue(state)

    @defer.inlineCallbacks
    def compute_state_delta(self, room_id, batch, sync_config, since_token, now_token,
                            full_state):
        """ Works out the differnce in state between the start of the timeline
        and the previous sync.

        Args:
            room_id(str):
            batch(synapse.handlers.sync.TimelineBatch): The timeline batch for
                the room that will be sent to the user.
            sync_config(synapse.handlers.sync.SyncConfig):
            since_token(str|None): Token of the end of the previous batch. May
                be None.
            now_token(str): Token of the end of the current batch.
            full_state(bool): Whether to force returning the full state.

        Returns:
             A deferred new event dictionary
        """
        # TODO(mjark) Check if the state events were received by the server
        # after the previous sync, since we need to include those state
        # updates even if they occured logically before the previous event.
        # TODO(mjark) Check for new redactions in the state events.

        with Measure(self.clock, "compute_state_delta"):
            if full_state:
                if batch:
                    current_state_ids = yield self.store.get_state_ids_for_event(
                        batch.events[-1].event_id
                    )

                    state_ids = yield self.store.get_state_ids_for_event(
                        batch.events[0].event_id
                    )
                else:
                    current_state_ids = yield self.get_state_at(
                        room_id, stream_position=now_token
                    )

                    state_ids = current_state_ids

                timeline_state = {
                    (event.type, event.state_key): event.event_id
                    for event in batch.events if event.is_state()
                }

                state_ids = _calculate_state(
                    timeline_contains=timeline_state,
                    timeline_start=state_ids,
                    previous={},
                    current=current_state_ids,
                )
            elif batch.limited:
                state_at_previous_sync = yield self.get_state_at(
                    room_id, stream_position=since_token
                )

                current_state_ids = yield self.store.get_state_ids_for_event(
                    batch.events[-1].event_id
                )

                state_at_timeline_start = yield self.store.get_state_ids_for_event(
                    batch.events[0].event_id
                )

                timeline_state = {
                    (event.type, event.state_key): event.event_id
                    for event in batch.events if event.is_state()
                }

                state_ids = _calculate_state(
                    timeline_contains=timeline_state,
                    timeline_start=state_at_timeline_start,
                    previous=state_at_previous_sync,
                    current=current_state_ids,
                )
            else:
                state_ids = {}

        state = {}
        if state_ids:
            state = yield self.store.get_events(state_ids.values())

        defer.returnValue({
            (e.type, e.state_key): e
            for e in sync_config.filter_collection.filter_room_state(state.values())
        })

    @defer.inlineCallbacks
    def unread_notifs_for_room_id(self, room_id, sync_config):
        with Measure(self.clock, "unread_notifs_for_room_id"):
            last_unread_event_id = yield self.store.get_last_receipt_event_id_for_user(
                user_id=sync_config.user.to_string(),
                room_id=room_id,
                receipt_type="m.read"
            )

            notifs = []
            if last_unread_event_id:
                notifs = yield self.store.get_unread_event_push_actions_by_room_for_user(
                    room_id, sync_config.user.to_string(), last_unread_event_id
                )
                defer.returnValue(notifs)

        # There is no new information in this period, so your notification
        # count is whatever it was last time.
        defer.returnValue(None)

    @defer.inlineCallbacks
    def generate_sync_result(self, sync_config, since_token=None, full_state=False):
        """Generates a sync result.

        Args:
            sync_config (SyncConfig)
            since_token (StreamToken)
            full_state (bool)

        Returns:
            Deferred(SyncResult)
        """
        logger.info("Calculating sync response for %r", sync_config.user)

        # NB: The now_token gets changed by some of the generate_sync_* methods,
        # this is due to some of the underlying streams not supporting the ability
        # to query up to a given point.
        # Always use the `now_token` in `SyncResultBuilder`
        now_token = yield self.event_sources.get_current_token()

        sync_result_builder = SyncResultBuilder(
            sync_config, full_state,
            since_token=since_token,
            now_token=now_token,
        )

        account_data_by_room = yield self._generate_sync_entry_for_account_data(
            sync_result_builder
        )

        res = yield self._generate_sync_entry_for_rooms(
            sync_result_builder, account_data_by_room
        )
        newly_joined_rooms, newly_joined_users = res

        block_all_presence_data = (
            since_token is None and
            sync_config.filter_collection.blocks_all_presence()
        )
        if not block_all_presence_data:
            yield self._generate_sync_entry_for_presence(
                sync_result_builder, newly_joined_rooms, newly_joined_users
            )

        yield self._generate_sync_entry_for_to_device(sync_result_builder)

        device_lists = yield self._generate_sync_entry_for_device_list(
            sync_result_builder
        )

        device_id = sync_config.device_id
        one_time_key_counts = {}
        if device_id:
            user_id = sync_config.user.to_string()
            one_time_key_counts = yield self.store.count_e2e_one_time_keys(
                user_id, device_id
            )

        defer.returnValue(SyncResult(
            presence=sync_result_builder.presence,
            account_data=sync_result_builder.account_data,
            joined=sync_result_builder.joined,
            invited=sync_result_builder.invited,
            archived=sync_result_builder.archived,
            to_device=sync_result_builder.to_device,
            device_lists=device_lists,
            device_one_time_keys_count=one_time_key_counts,
            next_batch=sync_result_builder.now_token,
        ))

    @measure_func("_generate_sync_entry_for_device_list")
    @defer.inlineCallbacks
    def _generate_sync_entry_for_device_list(self, sync_result_builder):
        user_id = sync_result_builder.sync_config.user.to_string()
        since_token = sync_result_builder.since_token

        if since_token and since_token.device_list_key:
            room_ids = yield self.store.get_rooms_for_user(user_id)

            user_ids_changed = set()
            changed = yield self.store.get_user_whose_devices_changed(
                since_token.device_list_key
            )
            for other_user_id in changed:
                other_room_ids = yield self.store.get_rooms_for_user(other_user_id)
                if room_ids.intersection(other_room_ids):
                    user_ids_changed.add(other_user_id)

            defer.returnValue(user_ids_changed)
        else:
            defer.returnValue([])

    @defer.inlineCallbacks
    def _generate_sync_entry_for_to_device(self, sync_result_builder):
        """Generates the portion of the sync response. Populates
        `sync_result_builder` with the result.

        Args:
            sync_result_builder(SyncResultBuilder)

        Returns:
            Deferred(dict): A dictionary containing the per room account data.
        """
        user_id = sync_result_builder.sync_config.user.to_string()
        device_id = sync_result_builder.sync_config.device_id
        now_token = sync_result_builder.now_token
        since_stream_id = 0
        if sync_result_builder.since_token is not None:
            since_stream_id = int(sync_result_builder.since_token.to_device_key)

        if since_stream_id != int(now_token.to_device_key):
            # We only delete messages when a new message comes in, but that's
            # fine so long as we delete them at some point.

            deleted = yield self.store.delete_messages_for_device(
                user_id, device_id, since_stream_id
            )
            logger.debug("Deleted %d to-device messages up to %d",
                         deleted, since_stream_id)

            messages, stream_id = yield self.store.get_new_messages_for_device(
                user_id, device_id, since_stream_id, now_token.to_device_key
            )

            logger.debug(
                "Returning %d to-device messages between %d and %d (current token: %d)",
                len(messages), since_stream_id, stream_id, now_token.to_device_key
            )
            sync_result_builder.now_token = now_token.copy_and_replace(
                "to_device_key", stream_id
            )
            sync_result_builder.to_device = messages
        else:
            sync_result_builder.to_device = []

    @defer.inlineCallbacks
    def _generate_sync_entry_for_account_data(self, sync_result_builder):
        """Generates the account data portion of the sync response. Populates
        `sync_result_builder` with the result.

        Args:
            sync_result_builder(SyncResultBuilder)

        Returns:
            Deferred(dict): A dictionary containing the per room account data.
        """
        sync_config = sync_result_builder.sync_config
        user_id = sync_result_builder.sync_config.user.to_string()
        since_token = sync_result_builder.since_token

        if since_token and not sync_result_builder.full_state:
            account_data, account_data_by_room = (
                yield self.store.get_updated_account_data_for_user(
                    user_id,
                    since_token.account_data_key,
                )
            )

            push_rules_changed = yield self.store.have_push_rules_changed_for_user(
                user_id, int(since_token.push_rules_key)
            )

            if push_rules_changed:
                account_data["m.push_rules"] = yield self.push_rules_for_user(
                    sync_config.user
                )
        else:
            account_data, account_data_by_room = (
                yield self.store.get_account_data_for_user(
                    sync_config.user.to_string()
                )
            )

            account_data['m.push_rules'] = yield self.push_rules_for_user(
                sync_config.user
            )

        account_data_for_user = sync_config.filter_collection.filter_account_data([
            {"type": account_data_type, "content": content}
            for account_data_type, content in account_data.items()
        ])

        sync_result_builder.account_data = account_data_for_user

        defer.returnValue(account_data_by_room)

    @defer.inlineCallbacks
    def _generate_sync_entry_for_presence(self, sync_result_builder, newly_joined_rooms,
                                          newly_joined_users):
        """Generates the presence portion of the sync response. Populates the
        `sync_result_builder` with the result.

        Args:
            sync_result_builder(SyncResultBuilder)
            newly_joined_rooms(list): List of rooms that the user has joined
                since the last sync (or empty if an initial sync)
            newly_joined_users(list): List of users that have joined rooms
                since the last sync (or empty if an initial sync)
        """
        now_token = sync_result_builder.now_token
        sync_config = sync_result_builder.sync_config
        user = sync_result_builder.sync_config.user

        presence_source = self.event_sources.sources["presence"]

        since_token = sync_result_builder.since_token
        if since_token and not sync_result_builder.full_state:
            presence_key = since_token.presence_key
            include_offline = True
        else:
            presence_key = None
            include_offline = False

        presence, presence_key = yield presence_source.get_new_events(
            user=user,
            from_key=presence_key,
            is_guest=sync_config.is_guest,
            include_offline=include_offline,
        )
        sync_result_builder.now_token = now_token.copy_and_replace(
            "presence_key", presence_key
        )

        extra_users_ids = set(newly_joined_users)
        for room_id in newly_joined_rooms:
            users = yield self.state.get_current_user_in_room(room_id)
            extra_users_ids.update(users)
        extra_users_ids.discard(user.to_string())

        if extra_users_ids:
            states = yield self.presence_handler.get_states(
                extra_users_ids,
            )
            presence.extend(states)

            # Deduplicate the presence entries so that there's at most one per user
            presence = {p.user_id: p for p in presence}.values()

        presence = sync_config.filter_collection.filter_presence(
            presence
        )

        sync_result_builder.presence = presence

    @defer.inlineCallbacks
    def _generate_sync_entry_for_rooms(self, sync_result_builder, account_data_by_room):
        """Generates the rooms portion of the sync response. Populates the
        `sync_result_builder` with the result.

        Args:
            sync_result_builder(SyncResultBuilder)
            account_data_by_room(dict): Dictionary of per room account data

        Returns:
            Deferred(tuple): Returns a 2-tuple of
            `(newly_joined_rooms, newly_joined_users)`
        """
        user_id = sync_result_builder.sync_config.user.to_string()
        block_all_room_ephemeral = (
            sync_result_builder.since_token is None and
            sync_result_builder.sync_config.filter_collection.blocks_all_room_ephemeral()
        )

        if block_all_room_ephemeral:
            ephemeral_by_room = {}
        else:
            now_token, ephemeral_by_room = yield self.ephemeral_by_room(
                sync_result_builder.sync_config,
                now_token=sync_result_builder.now_token,
                since_token=sync_result_builder.since_token,
            )
            sync_result_builder.now_token = now_token

        # We check up front if anything has changed, if it hasn't then there is
        # no point in going futher.
        since_token = sync_result_builder.since_token
        if not sync_result_builder.full_state:
            if since_token and not ephemeral_by_room and not account_data_by_room:
                have_changed = yield self._have_rooms_changed(sync_result_builder)
                if not have_changed:
                    tags_by_room = yield self.store.get_updated_tags(
                        user_id,
                        since_token.account_data_key,
                    )
                    if not tags_by_room:
                        logger.debug("no-oping sync")
                        defer.returnValue(([], []))

        ignored_account_data = yield self.store.get_global_account_data_by_type_for_user(
            "m.ignored_user_list", user_id=user_id,
        )

        if ignored_account_data:
            ignored_users = ignored_account_data.get("ignored_users", {}).keys()
        else:
            ignored_users = frozenset()

        if since_token:
            res = yield self._get_rooms_changed(sync_result_builder, ignored_users)
            room_entries, invited, newly_joined_rooms = res

            tags_by_room = yield self.store.get_updated_tags(
                user_id, since_token.account_data_key,
            )
        else:
            res = yield self._get_all_rooms(sync_result_builder, ignored_users)
            room_entries, invited, newly_joined_rooms = res

            tags_by_room = yield self.store.get_tags_for_user(user_id)

        def handle_room_entries(room_entry):
            return self._generate_room_entry(
                sync_result_builder,
                ignored_users,
                room_entry,
                ephemeral=ephemeral_by_room.get(room_entry.room_id, []),
                tags=tags_by_room.get(room_entry.room_id),
                account_data=account_data_by_room.get(room_entry.room_id, {}),
                always_include=sync_result_builder.full_state,
            )

        yield concurrently_execute(handle_room_entries, room_entries, 10)

        sync_result_builder.invited.extend(invited)

        # Now we want to get any newly joined users
        newly_joined_users = set()
        if since_token:
            for joined_sync in sync_result_builder.joined:
                it = itertools.chain(
                    joined_sync.timeline.events, joined_sync.state.values()
                )
                for event in it:
                    if event.type == EventTypes.Member:
                        if event.membership == Membership.JOIN:
                            newly_joined_users.add(event.state_key)

        defer.returnValue((newly_joined_rooms, newly_joined_users))

    @defer.inlineCallbacks
    def _have_rooms_changed(self, sync_result_builder):
        """Returns whether there may be any new events that should be sent down
        the sync. Returns True if there are.
        """
        user_id = sync_result_builder.sync_config.user.to_string()
        since_token = sync_result_builder.since_token
        now_token = sync_result_builder.now_token

        assert since_token

        # Get a list of membership change events that have happened.
        rooms_changed = yield self.store.get_membership_changes_for_user(
            user_id, since_token.room_key, now_token.room_key
        )

        if rooms_changed:
            defer.returnValue(True)

        app_service = self.store.get_app_service_by_user_id(user_id)
        if app_service:
            rooms = yield self.store.get_app_service_rooms(app_service)
            joined_room_ids = set(r.room_id for r in rooms)
        else:
            joined_room_ids = yield self.store.get_rooms_for_user(user_id)

        stream_id = RoomStreamToken.parse_stream_token(since_token.room_key).stream
        for room_id in joined_room_ids:
            if self.store.has_room_changed_since(room_id, stream_id):
                defer.returnValue(True)
        defer.returnValue(False)

    @defer.inlineCallbacks
    def _get_rooms_changed(self, sync_result_builder, ignored_users):
        """Gets the the changes that have happened since the last sync.

        Args:
            sync_result_builder(SyncResultBuilder)
            ignored_users(set(str)): Set of users ignored by user.

        Returns:
            Deferred(tuple): Returns a tuple of the form:
            `([RoomSyncResultBuilder], [InvitedSyncResult], newly_joined_rooms)`
        """
        user_id = sync_result_builder.sync_config.user.to_string()
        since_token = sync_result_builder.since_token
        now_token = sync_result_builder.now_token
        sync_config = sync_result_builder.sync_config

        assert since_token

        app_service = self.store.get_app_service_by_user_id(user_id)
        if app_service:
            rooms = yield self.store.get_app_service_rooms(app_service)
            joined_room_ids = set(r.room_id for r in rooms)
        else:
            joined_room_ids = yield self.store.get_rooms_for_user(user_id)

        # Get a list of membership change events that have happened.
        rooms_changed = yield self.store.get_membership_changes_for_user(
            user_id, since_token.room_key, now_token.room_key
        )

        mem_change_events_by_room_id = {}
        for event in rooms_changed:
            mem_change_events_by_room_id.setdefault(event.room_id, []).append(event)

        newly_joined_rooms = []
        room_entries = []
        invited = []
        for room_id, events in mem_change_events_by_room_id.items():
            non_joins = [e for e in events if e.membership != Membership.JOIN]
            has_join = len(non_joins) != len(events)

            # We want to figure out if we joined the room at some point since
            # the last sync (even if we have since left). This is to make sure
            # we do send down the room, and with full state, where necessary
            if room_id in joined_room_ids or has_join:
                old_state_ids = yield self.get_state_at(room_id, since_token)
                old_mem_ev_id = old_state_ids.get((EventTypes.Member, user_id), None)
                old_mem_ev = None
                if old_mem_ev_id:
                    old_mem_ev = yield self.store.get_event(
                        old_mem_ev_id, allow_none=True
                    )
                if not old_mem_ev or old_mem_ev.membership != Membership.JOIN:
                    newly_joined_rooms.append(room_id)

                if room_id in joined_room_ids:
                    continue

            if not non_joins:
                continue

            # Only bother if we're still currently invited
            should_invite = non_joins[-1].membership == Membership.INVITE
            if should_invite:
                if event.sender not in ignored_users:
                    room_sync = InvitedSyncResult(room_id, invite=non_joins[-1])
                    if room_sync:
                        invited.append(room_sync)

            # Always include leave/ban events. Just take the last one.
            # TODO: How do we handle ban -> leave in same batch?
            leave_events = [
                e for e in non_joins
                if e.membership in (Membership.LEAVE, Membership.BAN)
            ]

            if leave_events:
                leave_event = leave_events[-1]
                leave_stream_token = yield self.store.get_stream_token_for_event(
                    leave_event.event_id
                )
                leave_token = since_token.copy_and_replace(
                    "room_key", leave_stream_token
                )

                if since_token and since_token.is_after(leave_token):
                    continue

                room_entries.append(RoomSyncResultBuilder(
                    room_id=room_id,
                    rtype="archived",
                    events=None,
                    newly_joined=room_id in newly_joined_rooms,
                    full_state=False,
                    since_token=since_token,
                    upto_token=leave_token,
                ))

        timeline_limit = sync_config.filter_collection.timeline_limit()

        # Get all events for rooms we're currently joined to.
        room_to_events = yield self.store.get_room_events_stream_for_rooms(
            room_ids=joined_room_ids,
            from_key=since_token.room_key,
            to_key=now_token.room_key,
            limit=timeline_limit + 1,
        )

        # We loop through all room ids, even if there are no new events, in case
        # there are non room events taht we need to notify about.
        for room_id in joined_room_ids:
            room_entry = room_to_events.get(room_id, None)

            if room_entry:
                events, start_key = room_entry

                prev_batch_token = now_token.copy_and_replace("room_key", start_key)

                room_entries.append(RoomSyncResultBuilder(
                    room_id=room_id,
                    rtype="joined",
                    events=events,
                    newly_joined=room_id in newly_joined_rooms,
                    full_state=False,
                    since_token=None if room_id in newly_joined_rooms else since_token,
                    upto_token=prev_batch_token,
                ))
            else:
                room_entries.append(RoomSyncResultBuilder(
                    room_id=room_id,
                    rtype="joined",
                    events=[],
                    newly_joined=room_id in newly_joined_rooms,
                    full_state=False,
                    since_token=since_token,
                    upto_token=since_token,
                ))

        defer.returnValue((room_entries, invited, newly_joined_rooms))

    @defer.inlineCallbacks
    def _get_all_rooms(self, sync_result_builder, ignored_users):
        """Returns entries for all rooms for the user.

        Args:
            sync_result_builder(SyncResultBuilder)
            ignored_users(set(str)): Set of users ignored by user.

        Returns:
            Deferred(tuple): Returns a tuple of the form:
            `([RoomSyncResultBuilder], [InvitedSyncResult], [])`
        """

        user_id = sync_result_builder.sync_config.user.to_string()
        since_token = sync_result_builder.since_token
        now_token = sync_result_builder.now_token
        sync_config = sync_result_builder.sync_config

        membership_list = (
            Membership.INVITE, Membership.JOIN, Membership.LEAVE, Membership.BAN
        )

        room_list = yield self.store.get_rooms_for_user_where_membership_is(
            user_id=user_id,
            membership_list=membership_list
        )

        room_entries = []
        invited = []

        for event in room_list:
            if event.membership == Membership.JOIN:
                room_entries.append(RoomSyncResultBuilder(
                    room_id=event.room_id,
                    rtype="joined",
                    events=None,
                    newly_joined=False,
                    full_state=True,
                    since_token=since_token,
                    upto_token=now_token,
                ))
            elif event.membership == Membership.INVITE:
                if event.sender in ignored_users:
                    continue
                invite = yield self.store.get_event(event.event_id)
                invited.append(InvitedSyncResult(
                    room_id=event.room_id,
                    invite=invite,
                ))
            elif event.membership in (Membership.LEAVE, Membership.BAN):
                # Always send down rooms we were banned or kicked from.
                if not sync_config.filter_collection.include_leave:
                    if event.membership == Membership.LEAVE:
                        if user_id == event.sender:
                            continue

                leave_token = now_token.copy_and_replace(
                    "room_key", "s%d" % (event.stream_ordering,)
                )
                room_entries.append(RoomSyncResultBuilder(
                    room_id=event.room_id,
                    rtype="archived",
                    events=None,
                    newly_joined=False,
                    full_state=True,
                    since_token=since_token,
                    upto_token=leave_token,
                ))

        defer.returnValue((room_entries, invited, []))

    @defer.inlineCallbacks
    def _generate_room_entry(self, sync_result_builder, ignored_users,
                             room_builder, ephemeral, tags, account_data,
                             always_include=False):
        """Populates the `joined` and `archived` section of `sync_result_builder`
        based on the `room_builder`.

        Args:
            sync_result_builder(SyncResultBuilder)
            ignored_users(set(str)): Set of users ignored by user.
            room_builder(RoomSyncResultBuilder)
            ephemeral(list): List of new ephemeral events for room
            tags(list): List of *all* tags for room, or None if there has been
                no change.
            account_data(list): List of new account data for room
            always_include(bool): Always include this room in the sync response,
                even if empty.
        """
        newly_joined = room_builder.newly_joined
        full_state = (
            room_builder.full_state
            or newly_joined
            or sync_result_builder.full_state
        )
        events = room_builder.events

        # We want to shortcut out as early as possible.
        if not (always_include or account_data or ephemeral or full_state):
            if events == [] and tags is None:
                return

        since_token = sync_result_builder.since_token
        now_token = sync_result_builder.now_token
        sync_config = sync_result_builder.sync_config

        room_id = room_builder.room_id
        since_token = room_builder.since_token
        upto_token = room_builder.upto_token

        batch = yield self._load_filtered_recents(
            room_id, sync_config,
            now_token=upto_token,
            since_token=since_token,
            recents=events,
            newly_joined_room=newly_joined,
        )

        account_data_events = []
        if tags is not None:
            account_data_events.append({
                "type": "m.tag",
                "content": {"tags": tags},
            })

        for account_data_type, content in account_data.items():
            account_data_events.append({
                "type": account_data_type,
                "content": content,
            })

        account_data = sync_config.filter_collection.filter_room_account_data(
            account_data_events
        )

        ephemeral = sync_config.filter_collection.filter_room_ephemeral(ephemeral)

        if not (always_include or batch or account_data or ephemeral or full_state):
            return

        state = yield self.compute_state_delta(
            room_id, batch, sync_config, since_token, now_token,
            full_state=full_state
        )

        if room_builder.rtype == "joined":
            unread_notifications = {}
            room_sync = JoinedSyncResult(
                room_id=room_id,
                timeline=batch,
                state=state,
                ephemeral=ephemeral,
                account_data=account_data_events,
                unread_notifications=unread_notifications,
            )

            if room_sync or always_include:
                notifs = yield self.unread_notifs_for_room_id(
                    room_id, sync_config
                )

                if notifs is not None:
                    unread_notifications["notification_count"] = notifs["notify_count"]
                    unread_notifications["highlight_count"] = notifs["highlight_count"]

                sync_result_builder.joined.append(room_sync)
        elif room_builder.rtype == "archived":
            room_sync = ArchivedSyncResult(
                room_id=room_id,
                timeline=batch,
                state=state,
                account_data=account_data,
            )
            if room_sync or always_include:
                sync_result_builder.archived.append(room_sync)
        else:
            raise Exception("Unrecognized rtype: %r", room_builder.rtype)


def _action_has_highlight(actions):
    for action in actions:
        try:
            if action.get("set_tweak", None) == "highlight":
                return action.get("value", True)
        except AttributeError:
            pass

    return False


def _calculate_state(timeline_contains, timeline_start, previous, current):
    """Works out what state to include in a sync response.

    Args:
        timeline_contains (dict): state in the timeline
        timeline_start (dict): state at the start of the timeline
        previous (dict): state at the end of the previous sync (or empty dict
            if this is an initial sync)
        current (dict): state at the end of the timeline

    Returns:
        dict
    """
    event_id_to_key = {
        e: key
        for key, e in itertools.chain(
            timeline_contains.items(),
            previous.items(),
            timeline_start.items(),
            current.items(),
        )
    }

    c_ids = set(e for e in current.values())
    tc_ids = set(e for e in timeline_contains.values())
    p_ids = set(e for e in previous.values())
    ts_ids = set(e for e in timeline_start.values())

    state_ids = ((c_ids | ts_ids) - p_ids) - tc_ids

    return {
        event_id_to_key[e]: e for e in state_ids
    }


class SyncResultBuilder(object):
    "Used to help build up a new SyncResult for a user"
    def __init__(self, sync_config, full_state, since_token, now_token):
        """
        Args:
            sync_config(SyncConfig)
            full_state(bool): The full_state flag as specified by user
            since_token(StreamToken): The token supplied by user, or None.
            now_token(StreamToken): The token to sync up to.
        """
        self.sync_config = sync_config
        self.full_state = full_state
        self.since_token = since_token
        self.now_token = now_token

        self.presence = []
        self.account_data = []
        self.joined = []
        self.invited = []
        self.archived = []
        self.device = []


class RoomSyncResultBuilder(object):
    """Stores information needed to create either a `JoinedSyncResult` or
    `ArchivedSyncResult`.
    """
    def __init__(self, room_id, rtype, events, newly_joined, full_state,
                 since_token, upto_token):
        """
        Args:
            room_id(str)
            rtype(str): One of `"joined"` or `"archived"`
            events(list): List of events to include in the room, (more events
                may be added when generating result).
            newly_joined(bool): If the user has newly joined the room
            full_state(bool): Whether the full state should be sent in result
            since_token(StreamToken): Earliest point to return events from, or None
            upto_token(StreamToken): Latest point to return events from.
        """
        self.room_id = room_id
        self.rtype = rtype
        self.events = events
        self.newly_joined = newly_joined
        self.full_state = full_state
        self.since_token = since_token
        self.upto_token = upto_token