summaryrefslogtreecommitdiff
path: root/apps/couch/src/couch_db.erl
blob: 17fabae13ac2afc1c1d57b1d726088dfa7dd1136 (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
% 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.

-module(couch_db).

-export([open/2,open_int/2,close/1,create/2,start_compact/1,get_db_info/1,get_design_docs/1]).
-export([open_ref_counted/2,is_idle/1,monitor/1,count_changes_since/2]).
-export([update_doc/3,update_doc/4,update_docs/4,update_docs/2,update_docs/3,delete_doc/3]).
-export([get_doc_info/2,open_doc/2,open_doc/3,open_doc_revs/4]).
-export([set_revs_limit/2,get_revs_limit/1]).
-export([get_missing_revs/2,name/1,doc_to_tree/1,get_update_seq/1,get_committed_update_seq/1]).
-export([enum_docs/4,enum_docs_since/5]).
-export([enum_docs_since_reduce_to_count/1,enum_docs_reduce_to_count/1]).
-export([increment_update_seq/1,get_purge_seq/1,purge_docs/2,get_last_purged/1]).
-export([start_link/3,open_doc_int/3,ensure_full_commit/1,ensure_full_commit/2]).
-export([set_security/2,get_security/1]).
-export([changes_since/4,changes_since/5,read_doc/2,new_revid/1]).
-export([check_is_admin/1, check_is_reader/1, get_doc_count/1]).
-export([reopen/1, make_doc/5]).

-include("couch_db.hrl").

start_link(DbName, Filepath, Options) ->
    case open_db_file(Filepath, Options) of
    {ok, Fd} ->
        {ok, UpdaterPid} = gen_server:start_link(couch_db_updater, {DbName,
            Filepath, Fd, Options}, []),
        unlink(Fd),
        gen_server:call(UpdaterPid, get_db);
    Else ->
        Else
    end.

open_db_file(Filepath, Options) ->
    case couch_file:open(Filepath, Options) of
    {ok, Fd} ->
        {ok, Fd};
    {error, enoent} ->
        % couldn't find file. is there a compact version? This can happen if
        % crashed during the file switch.
        case couch_file:open(Filepath ++ ".compact") of
        {ok, Fd} ->
            ?LOG_INFO("Found ~s~s compaction file, using as primary storage.", [Filepath, ".compact"]),
            ok = file:rename(Filepath ++ ".compact", Filepath),
            ok = couch_file:sync(Filepath),
            {ok, Fd};
        {error, enoent} ->
            {not_found, no_db_file}
        end;
    Error ->
        Error
    end.


create(DbName, Options) ->
    couch_server:create(DbName, Options).

% this is for opening a database for internal purposes like the replicator
% or the view indexer. it never throws a reader error.
open_int(DbName, Options) ->
    couch_server:open(DbName, Options).

% this should be called anytime an http request opens the database.
% it ensures that the http userCtx is a valid reader
open(DbName, Options) ->
    case couch_server:open(DbName, Options) of
        {ok, Db} ->
            try
                check_is_reader(Db),
                {ok, Db}
            catch
                throw:Error ->
                    close(Db),
                    throw(Error)
            end;
        Else -> Else
    end.

reopen(#db{main_pid = Pid, fd = Fd, fd_monitor = OldRef, user_ctx = UserCtx}) ->
    {ok, #db{fd = NewFd} = NewDb} = gen_server:call(Pid, get_db, infinity),
    case NewFd =:= Fd of
    true ->
        {ok, NewDb#db{user_ctx = UserCtx}};
    false ->
        erlang:demonitor(OldRef),
        NewRef = erlang:monitor(process, NewFd),
        {ok, NewDb#db{user_ctx = UserCtx, fd_monitor = NewRef}}
    end.

ensure_full_commit(#db{main_pid=Pid, instance_start_time=StartTime}) ->
    ok = gen_server:call(Pid, full_commit, infinity),
    {ok, StartTime}.

ensure_full_commit(Db, RequiredSeq) ->
    #db{main_pid=Pid, instance_start_time=StartTime} = Db,
    ok = gen_server:call(Pid, {full_commit, RequiredSeq}, infinity),
    {ok, StartTime}.

close(#db{fd_monitor=RefCntr}) ->
    erlang:demonitor(RefCntr).

open_ref_counted(MainPid, OpenedPid) ->
    gen_server:call(MainPid, {open_ref_count, OpenedPid}).

is_idle(#db{compactor_pid=nil, waiting_delayed_commit=nil} = Db) ->
    case erlang:process_info(Db#db.fd, monitored_by) of
    undefined ->
        true;
    {monitored_by, Pids} ->
        (Pids -- [Db#db.main_pid, whereis(couch_stats_collector)]) =:= []
    end;
is_idle(_Db) ->
    false.

monitor(#db{main_pid=MainPid}) ->
    erlang:monitor(process, MainPid).

start_compact(#db{main_pid=Pid}) ->
    {ok, _} = gen_server:call(Pid, start_compact),
    ok.

delete_doc(Db, Id, Revisions) ->
    DeletedDocs = [#doc{id=Id, revs=[Rev], deleted=true} || Rev <- Revisions],
    {ok, [Result]} = update_docs(Db, DeletedDocs, []),
    {ok, Result}.

open_doc(Db, IdOrDocInfo) ->
    open_doc(Db, IdOrDocInfo, []).

open_doc(Db, Id, Options) ->
    increment_stat(Db, {couchdb, database_reads}),
    case open_doc_int(Db, Id, Options) of
    {ok, #doc{deleted=true}=Doc} ->
        case lists:member(deleted, Options) of
        true ->
            apply_open_options({ok, Doc},Options);
        false ->
            {not_found, deleted}
        end;
    Else ->
        apply_open_options(Else,Options)
    end.

apply_open_options({ok, Doc},Options) ->
    apply_open_options2(Doc,Options);
apply_open_options(Else,_Options) ->
    Else.

apply_open_options2(Doc,[]) ->
    {ok, Doc};
apply_open_options2(#doc{atts=Atts,revs=Revs}=Doc,
        [{atts_since, PossibleAncestors}|Rest]) ->
    RevPos = find_ancestor_rev_pos(Revs, PossibleAncestors),
    apply_open_options2(Doc#doc{atts=[A#att{data=
        if AttPos>RevPos -> Data; true -> stub end}
        || #att{revpos=AttPos,data=Data}=A <- Atts]}, Rest);
apply_open_options2(Doc,[_|Rest]) ->
    apply_open_options2(Doc,Rest).


find_ancestor_rev_pos({_, []}, _AttsSinceRevs) ->
    0;
find_ancestor_rev_pos(_DocRevs, []) ->
    0;
find_ancestor_rev_pos({RevPos, [RevId|Rest]}, AttsSinceRevs) ->
    case lists:member({RevPos, RevId}, AttsSinceRevs) of
    true ->
        RevPos;
    false ->
        find_ancestor_rev_pos({RevPos - 1, Rest}, AttsSinceRevs)
    end.

open_doc_revs(Db, Id, Revs, Options) ->
    increment_stat(Db, {couchdb, database_reads}),
    [{ok, Results}] = open_doc_revs_int(Db, [{Id, Revs}], Options),
    {ok, [apply_open_options(Result, Options) || Result <- Results]}.

% Each returned result is a list of tuples:
% {Id, MissingRevs, PossibleAncestors}
% if no revs are missing, it's omitted from the results.
get_missing_revs(Db, IdRevsList) ->
    Results = get_full_doc_infos(Db, [Id1 || {Id1, _Revs} <- IdRevsList]),
    {ok, find_missing(IdRevsList, Results)}.

find_missing([], []) ->
    [];
find_missing([{Id, Revs}|RestIdRevs], [{ok, FullInfo} | RestLookupInfo]) ->
    case couch_key_tree:find_missing(FullInfo#full_doc_info.rev_tree, Revs) of
    [] ->
        find_missing(RestIdRevs, RestLookupInfo);
    MissingRevs ->
        #doc_info{revs=RevsInfo} = couch_doc:to_doc_info(FullInfo),
        LeafRevs = [Rev || #rev_info{rev=Rev} <- RevsInfo],
        % Find the revs that are possible parents of this rev
        PossibleAncestors =
        lists:foldl(fun({LeafPos, LeafRevId}, Acc) ->
            % this leaf is a "possible ancenstor" of the missing
            % revs if this LeafPos lessthan any of the missing revs
            case lists:any(fun({MissingPos, _}) ->
                    LeafPos < MissingPos end, MissingRevs) of
            true ->
                [{LeafPos, LeafRevId} | Acc];
            false ->
                Acc
            end
        end, [], LeafRevs),
        [{Id, MissingRevs, PossibleAncestors} |
                find_missing(RestIdRevs, RestLookupInfo)]
    end;
find_missing([{Id, Revs}|RestIdRevs], [not_found | RestLookupInfo]) ->
    [{Id, Revs, []} | find_missing(RestIdRevs, RestLookupInfo)].

get_doc_info(Db, Id) ->
    case get_full_doc_info(Db, Id) of
    {ok, DocInfo} ->
        {ok, couch_doc:to_doc_info(DocInfo)};
    Else ->
        Else
    end.

%   returns {ok, DocInfo} or not_found
get_full_doc_info(Db, Id) ->
    [Result] = get_full_doc_infos(Db, [Id]),
    Result.

get_full_doc_infos(Db, Ids) ->
    couch_btree:lookup(Db#db.id_tree, Ids).

increment_update_seq(#db{main_pid=Pid}) ->
    gen_server:call(Pid, increment_update_seq).

purge_docs(#db{main_pid=Pid}, IdsRevs) ->
    gen_server:call(Pid, {purge_docs, IdsRevs}).

get_committed_update_seq(#db{committed_update_seq=Seq}) ->
    Seq.

get_update_seq(#db{update_seq=Seq})->
    Seq.

get_purge_seq(#db{header=#db_header{purge_seq=PurgeSeq}})->
    PurgeSeq.

get_last_purged(#db{header=#db_header{purged_docs=nil}}) ->
    {ok, []};
get_last_purged(#db{fd=Fd, header=#db_header{purged_docs=PurgedPointer}}) ->
    couch_file:pread_term(Fd, PurgedPointer).

get_doc_count(Db) ->
    {ok, {Count, _, _}}  = couch_btree:full_reduce(Db#db.id_tree),
    {ok, Count}.

get_db_info(Db) ->
    #db{fd=Fd,
        header=#db_header{disk_version=DiskVersion},
        compactor_pid=Compactor,
        update_seq=SeqNum,
        name=Name,
        id_tree=FullDocBtree,
        instance_start_time=StartTime,
        committed_update_seq=CommittedUpdateSeq} = Db,
    {ok, Size} = couch_file:bytes(Fd),
    {ok, {Count, DelCount, DataSize}} = couch_btree:full_reduce(FullDocBtree),
    InfoList = [
        {db_name, Name},
        {doc_count, Count},
        {doc_del_count, DelCount},
        {update_seq, SeqNum},
        {purge_seq, couch_db:get_purge_seq(Db)},
        {compact_running, Compactor/=nil},
        {disk_size, Size},
        {other, {[{data_size, DataSize}]}},
        {instance_start_time, StartTime},
        {disk_format_version, DiskVersion},
        {committed_update_seq, CommittedUpdateSeq}
        ],
    {ok, InfoList}.

get_design_docs(#db{name = <<"shards/", _/binary>> = ShardName}) ->
    {_, Ref} = spawn_monitor(fun() ->
        exit(fabric:design_docs(mem3:dbname(ShardName)))
    end),
    receive {'DOWN', Ref, _, _, Response} ->
        Response
    end;
get_design_docs(#db{id_tree=Btree}=Db) ->
    {ok, _, Docs} = couch_view:fold(
        #view{btree=Btree},
        fun(#full_doc_info{deleted = true}, _Reds, AccDocs) ->
            {ok, AccDocs};
        (#full_doc_info{id= <<"_design/",_/binary>>}=FullDocInfo, _Reds, AccDocs) ->
            {ok, Doc} = couch_db:open_doc_int(Db, FullDocInfo, []),
            {ok, [Doc | AccDocs]};
        (_, _Reds, AccDocs) ->
            {stop, AccDocs}
        end,
        [], [{start_key, <<"_design/">>}, {end_key_gt, <<"_design0">>}]),
    {ok, Docs}.

check_is_admin(#db{user_ctx=#user_ctx{name=Name,roles=Roles}}=Db) ->
    {Admins} = get_admins(Db),
    AdminRoles = [<<"_admin">> | couch_util:get_value(<<"roles">>, Admins, [])],
    AdminNames = couch_util:get_value(<<"names">>, Admins,[]),
    case AdminRoles -- Roles of
    AdminRoles -> % same list, not an admin role
        case AdminNames -- [Name] of
        AdminNames -> % same names, not an admin
            throw({unauthorized, <<"You are not a db or server admin.">>});
        _ ->
            ok
        end;
    _ ->
        ok
    end.

check_is_reader(#db{user_ctx=#user_ctx{name=Name,roles=Roles}=UserCtx}=Db) ->
    case (catch check_is_admin(Db)) of
    ok -> ok;
    _ ->
        {Readers} = get_readers(Db),
        ReaderRoles = couch_util:get_value(<<"roles">>, Readers,[]),
        WithAdminRoles = [<<"_admin">> | ReaderRoles],
        ReaderNames = couch_util:get_value(<<"names">>, Readers,[]),
        case ReaderRoles ++ ReaderNames of
        [] -> ok; % no readers == public access
        _Else ->
            case WithAdminRoles -- Roles of
            WithAdminRoles -> % same list, not an reader role
                case ReaderNames -- [Name] of
                ReaderNames -> % same names, not a reader
                    ?LOG_DEBUG("Not a reader: UserCtx ~p vs Names ~p Roles ~p",[UserCtx, ReaderNames, WithAdminRoles]),
                    throw({unauthorized, <<"You are not authorized to access this db.">>});
                _ ->
                    ok
                end;
            _ ->
                ok
            end
        end
    end.

get_admins(#db{security=SecProps}) ->
    couch_util:get_value(<<"admins">>, SecProps, {[]}).

get_readers(#db{security=SecProps}) ->
    couch_util:get_value(<<"readers">>, SecProps, {[]}).

get_security(#db{security=SecProps}) ->
    {SecProps}.

set_security(#db{main_pid=Pid}=Db, {NewSecProps}) when is_list(NewSecProps) ->
    check_is_admin(Db),
    ok = validate_security_object(NewSecProps),
    ok = gen_server:call(Pid, {set_security, NewSecProps}, infinity),
    {ok, _} = ensure_full_commit(Db),
    ok;
set_security(_, _) ->
    throw(bad_request).

validate_security_object(SecProps) ->
    Admins = couch_util:get_value(<<"admins">>, SecProps, {[]}),
    Readers = couch_util:get_value(<<"readers">>, SecProps, {[]}),
    ok = validate_names_and_roles(Admins),
    ok = validate_names_and_roles(Readers),
    ok.

% validate user input
validate_names_and_roles({Props}) when is_list(Props) ->
    case couch_util:get_value(<<"names">>,Props,[]) of
    Ns when is_list(Ns) ->
            [throw("names must be a JSON list of strings") ||N <- Ns, not is_binary(N)],
            Ns;
    _ -> throw("names must be a JSON list of strings")
    end,
    case couch_util:get_value(<<"roles">>,Props,[]) of
    Rs when is_list(Rs) ->
        [throw("roles must be a JSON list of strings") ||R <- Rs, not is_binary(R)],
        Rs;
    _ -> throw("roles must be a JSON list of strings")
    end,
    ok.

get_revs_limit(#db{revs_limit=Limit}) ->
    Limit.

set_revs_limit(#db{main_pid=Pid}=Db, Limit) when Limit > 0 ->
    check_is_admin(Db),
    gen_server:call(Pid, {set_revs_limit, Limit}, infinity);
set_revs_limit(_Db, _Limit) ->
    throw(invalid_revs_limit).

name(#db{name=Name}) ->
    Name.

update_doc(Db, Doc, Options) ->
    update_doc(Db, Doc, Options, interactive_edit).

update_doc(Db, Doc, Options, UpdateType) ->
    case update_docs(Db, [Doc], Options, UpdateType) of
    {ok, [{ok, NewRev}]} ->
        {ok, NewRev};
    {ok, [{{_Id, _Rev}, Error}]} ->
        throw(Error);
    {ok, [Error]} ->
        throw(Error);
    {ok, []} ->
        % replication success
        {Pos, [RevId | _]} = Doc#doc.revs,
        {ok, {Pos, RevId}}
    end.

update_docs(Db, Docs) ->
    update_docs(Db, Docs, []).

% group_alike_docs groups the sorted documents into sublist buckets, by id.
% ([DocA, DocA, DocB, DocC], []) -> [[DocA, DocA], [DocB], [DocC]]
group_alike_docs(Docs) ->
    Sorted = lists:sort(fun(#doc{id=A},#doc{id=B})-> A < B end, Docs),
    group_alike_docs(Sorted, []).

group_alike_docs([], Buckets) ->
    lists:reverse(Buckets);
group_alike_docs([Doc|Rest], []) ->
    group_alike_docs(Rest, [[Doc]]);
group_alike_docs([Doc|Rest], [Bucket|RestBuckets]) ->
    [#doc{id=BucketId}|_] = Bucket,
    case Doc#doc.id == BucketId of
    true ->
        % add to existing bucket
        group_alike_docs(Rest, [[Doc|Bucket]|RestBuckets]);
    false ->
        % add to new bucket
       group_alike_docs(Rest, [[Doc]|[Bucket|RestBuckets]])
    end.

validate_doc_update(#db{}=Db, #doc{id= <<"_design/",_/binary>>}, _GetDiskDocFun) ->
    catch check_is_admin(Db);
validate_doc_update(#db{validate_doc_funs = undefined} = Db, Doc, Fun) ->
    ValidationFuns = load_validation_funs(Db),
    validate_doc_update(Db#db{validate_doc_funs = ValidationFuns}, Doc, Fun);
validate_doc_update(#db{validate_doc_funs=[]}, _Doc, _GetDiskDocFun) ->
    ok;
validate_doc_update(_Db, #doc{id= <<"_local/",_/binary>>}, _GetDiskDocFun) ->
    ok;
validate_doc_update(Db, Doc, GetDiskDocFun) ->
    DiskDoc = GetDiskDocFun(),
    JsonCtx = couch_util:json_user_ctx(Db),
    SecObj = get_security(Db),
    try [case Fun(Doc, DiskDoc, JsonCtx, SecObj) of
            ok -> ok;
            Error -> throw(Error)
        end || Fun <- Db#db.validate_doc_funs],
        ok
    catch
        throw:Error ->
            Error
    end.

% to be safe, spawn a middleman here
load_validation_funs(#db{main_pid = Pid} = Db) ->
    {_, Ref} = spawn_monitor(fun() ->
        {ok, DesignDocs} = get_design_docs(Db),
        exit({ok, lists:flatmap(fun(DesignDoc) ->
            case couch_doc:get_validate_doc_fun(DesignDoc) of
            nil ->
                [];
            Fun ->
                [Fun]
            end
        end, DesignDocs)})
    end),
    receive
    {'DOWN', Ref, _, _, {ok, Funs}} ->
        gen_server:cast(Pid, {load_validation_funs, Funs}),
        Funs;
    {'DOWN', Ref, _, _, Reason} ->
        ?LOG_ERROR("could not load validation funs ~p", [Reason]),
        throw(internal_server_error)
    end.

prep_and_validate_update(Db, #doc{id=Id,revs={RevStart, Revs}}=Doc,
        OldFullDocInfo, LeafRevsDict, AllowConflict) ->
    case Revs of
    [PrevRev|_] ->
        case dict:find({RevStart, PrevRev}, LeafRevsDict) of
        {ok, {Deleted, DiskSp, DiskRevs}} ->
            case couch_doc:has_stubs(Doc) of
            true ->
                DiskDoc = make_doc(Db, Id, Deleted, DiskSp, DiskRevs),
                Doc2 = couch_doc:merge_stubs(Doc, DiskDoc),
                {validate_doc_update(Db, Doc2, fun() -> DiskDoc end), Doc2};
            false ->
                LoadDiskDoc = fun() -> make_doc(Db,Id,Deleted,DiskSp,DiskRevs) end,
                {validate_doc_update(Db, Doc, LoadDiskDoc), Doc}
            end;
        error when AllowConflict ->
            couch_doc:merge_stubs(Doc, #doc{}), % will generate error if
                                                        % there are stubs
            {validate_doc_update(Db, Doc, fun() -> nil end), Doc};
        error ->
            {conflict, Doc}
        end;
    [] ->
        % new doc, and we have existing revs.
        % reuse existing deleted doc
        if OldFullDocInfo#full_doc_info.deleted orelse AllowConflict ->
            {validate_doc_update(Db, Doc, fun() -> nil end), Doc};
        true ->
            {conflict, Doc}
        end
    end.



prep_and_validate_updates(_Db, [], [], _AllowConflict, AccPrepped,
        AccFatalErrors) ->
   {AccPrepped, AccFatalErrors};
prep_and_validate_updates(Db, [DocBucket|RestBuckets], [not_found|RestLookups],
        AllowConflict, AccPrepped, AccErrors) ->
    [#doc{id=Id}|_]=DocBucket,
    % no existing revs are known,
    {PreppedBucket, AccErrors3} = lists:foldl(
        fun(#doc{revs=Revs}=Doc, {AccBucket, AccErrors2}) ->
            case couch_doc:has_stubs(Doc) of
            true ->
                couch_doc:merge_stubs(Doc, #doc{}); % will throw exception
            false -> ok
            end,
            case Revs of
            {0, []} ->
                case validate_doc_update(Db, Doc, fun() -> nil end) of
                ok ->
                    {[Doc | AccBucket], AccErrors2};
                Error ->
                    {AccBucket, [{{Id, {0, []}}, Error} | AccErrors2]}
                end;
            _ ->
                % old revs specified but none exist, a conflict
                {AccBucket, [{{Id, Revs}, conflict} | AccErrors2]}
            end
        end,
        {[], AccErrors}, DocBucket),

    prep_and_validate_updates(Db, RestBuckets, RestLookups, AllowConflict,
            [PreppedBucket | AccPrepped], AccErrors3);
prep_and_validate_updates(Db, [DocBucket|RestBuckets],
        [{ok, #full_doc_info{rev_tree=OldRevTree}=OldFullDocInfo}|RestLookups],
        AllowConflict, AccPrepped, AccErrors) ->
    Leafs = couch_key_tree:get_all_leafs(OldRevTree),
    LeafRevsDict = dict:from_list([{{Start, RevId}, {Del, Ptr, Revs}} ||
            {#leaf{deleted=Del, ptr=Ptr}, {Start, [RevId|_]}=Revs} <- Leafs]),
    {PreppedBucket, AccErrors3} = lists:foldl(
        fun(Doc, {Docs2Acc, AccErrors2}) ->
            case prep_and_validate_update(Db, Doc, OldFullDocInfo,
                    LeafRevsDict, AllowConflict) of
            {ok, Doc2} ->
                {[Doc2 | Docs2Acc], AccErrors2};
            {Error, #doc{id=Id,revs=Revs}} ->
                % Record the error
                {Docs2Acc, [{{Id, Revs}, Error} |AccErrors2]}
            end
        end,
        {[], AccErrors}, DocBucket),
    prep_and_validate_updates(Db, RestBuckets, RestLookups, AllowConflict,
            [PreppedBucket | AccPrepped], AccErrors3).


update_docs(Db, Docs, Options) ->
    update_docs(Db, Docs, Options, interactive_edit).


prep_and_validate_replicated_updates(_Db, [], [], AccPrepped, AccErrors) ->
    Errors2 = [{{Id, {Pos, Rev}}, Error} ||
            {#doc{id=Id,revs={Pos,[Rev|_]}}, Error} <- AccErrors],
    {lists:reverse(AccPrepped), lists:reverse(Errors2)};
prep_and_validate_replicated_updates(Db, [Bucket|RestBuckets], [OldInfo|RestOldInfo], AccPrepped, AccErrors) ->
    case OldInfo of
    not_found ->
        {ValidatedBucket, AccErrors3} = lists:foldl(
            fun(Doc, {AccPrepped2, AccErrors2}) ->
                case couch_doc:has_stubs(Doc) of
                true ->
                    couch_doc:merge_stubs(Doc, #doc{}); % will throw exception
                false -> ok
                end,
                case validate_doc_update(Db, Doc, fun() -> nil end) of
                ok ->
                    {[Doc | AccPrepped2], AccErrors2};
                Error ->
                    {AccPrepped2, [{Doc, Error} | AccErrors2]}
                end
            end,
            {[], AccErrors}, Bucket),
        prep_and_validate_replicated_updates(Db, RestBuckets, RestOldInfo, [ValidatedBucket | AccPrepped], AccErrors3);
    {ok, #full_doc_info{rev_tree=OldTree}} ->
        NewRevTree = lists:foldl(
            fun(NewDoc, AccTree) ->
                {NewTree, _} = couch_key_tree:merge(AccTree,
                    couch_db:doc_to_tree(NewDoc), Db#db.revs_limit),
                NewTree
            end,
            OldTree, Bucket),
        Leafs = couch_key_tree:get_all_leafs_full(NewRevTree),
        LeafRevsFullDict = dict:from_list( [{{Start, RevId}, FullPath} || {Start, [{RevId, _}|_]}=FullPath <- Leafs]),
        {ValidatedBucket, AccErrors3} =
        lists:foldl(
            fun(#doc{id=Id,revs={Pos, [RevId|_]}}=Doc, {AccValidated, AccErrors2}) ->
                case dict:find({Pos, RevId}, LeafRevsFullDict) of
                {ok, {Start, Path}} ->
                    % our unflushed doc is a leaf node. Go back on the path
                    % to find the previous rev that's on disk.

                    LoadPrevRevFun = fun() ->
                                make_first_doc_on_disk(Db,Id,Start-1, tl(Path))
                            end,

                    case couch_doc:has_stubs(Doc) of
                    true ->
                        DiskDoc = LoadPrevRevFun(),
                        Doc2 = couch_doc:merge_stubs(Doc, DiskDoc),
                        GetDiskDocFun = fun() -> DiskDoc end;
                    false ->
                        Doc2 = Doc,
                        GetDiskDocFun = LoadPrevRevFun
                    end,

                    case validate_doc_update(Db, Doc2, GetDiskDocFun) of
                    ok ->
                        {[Doc2 | AccValidated], AccErrors2};
                    Error ->
                        {AccValidated, [{Doc, Error} | AccErrors2]}
                    end;
                _ ->
                    % this doc isn't a leaf or already exists in the tree.
                    % ignore but consider it a success.
                    {AccValidated, AccErrors2}
                end
            end,
            {[], AccErrors}, Bucket),
        prep_and_validate_replicated_updates(Db, RestBuckets, RestOldInfo,
                [ValidatedBucket | AccPrepped], AccErrors3)
    end.



new_revid(#doc{body=Body,revs={OldStart,OldRevs},
        atts=Atts,deleted=Deleted}) ->
    case [{N, T, M} || #att{name=N,type=T,md5=M} <- Atts, M =/= <<>>] of
    Atts2 when length(Atts) =/= length(Atts2) ->
        % We must have old style non-md5 attachments
        ?l2b(integer_to_list(couch_util:rand32()));
    Atts2 ->
        OldRev = case OldRevs of [] -> 0; [OldRev0|_] -> OldRev0 end,
        couch_util:md5(term_to_binary([Deleted, OldStart, OldRev, Body, Atts2]))
    end.

new_revs([], OutBuckets, IdRevsAcc) ->
    {lists:reverse(OutBuckets), IdRevsAcc};
new_revs([Bucket|RestBuckets], OutBuckets, IdRevsAcc) ->
    {NewBucket, IdRevsAcc3} = lists:mapfoldl(
        fun(#doc{id=Id,revs={Start, RevIds}}=Doc, IdRevsAcc2)->
        NewRevId = new_revid(Doc),
        {Doc#doc{revs={Start+1, [NewRevId | RevIds]}},
            [{{Id, {Start, RevIds}}, {ok, {Start+1, NewRevId}}} | IdRevsAcc2]}
    end, IdRevsAcc, Bucket),
    new_revs(RestBuckets, [NewBucket|OutBuckets], IdRevsAcc3).

check_dup_atts(#doc{atts=Atts}=Doc) ->
    Atts2 = lists:sort(fun(#att{name=N1}, #att{name=N2}) -> N1 < N2 end, Atts),
    check_dup_atts2(Atts2),
    Doc.

check_dup_atts2([#att{name=N}, #att{name=N} | _]) ->
    throw({bad_request, <<"Duplicate attachments">>});
check_dup_atts2([_ | Rest]) ->
    check_dup_atts2(Rest);
check_dup_atts2(_) ->
    ok.


update_docs(Db, Docs, Options, replicated_changes) ->
    increment_stat(Db, {couchdb, database_writes}),
    DocBuckets = group_alike_docs(Docs),

    case (Db#db.validate_doc_funs /= []) orelse
        lists:any(
            fun(#doc{id= <<?DESIGN_DOC_PREFIX, _/binary>>}) -> true;
            (#doc{atts=Atts}) ->
                Atts /= []
            end, Docs) of
    true ->
        Ids = [Id || [#doc{id=Id}|_] <- DocBuckets],
        ExistingDocs = get_full_doc_infos(Db, Ids),

        {DocBuckets2, DocErrors} =
                prep_and_validate_replicated_updates(Db, DocBuckets, ExistingDocs, [], []),
        DocBuckets3 = [Bucket || [_|_]=Bucket <- DocBuckets2]; % remove empty buckets
    false ->
        DocErrors = [],
        DocBuckets3 = DocBuckets
    end,
    DocBuckets4 = [[doc_flush_atts(check_dup_atts(Doc), Db#db.fd)
            || Doc <- Bucket] || Bucket <- DocBuckets3],
    {ok, []} = write_and_commit(Db, DocBuckets4, [], [merge_conflicts | Options]),
    {ok, DocErrors};

update_docs(Db, Docs, Options, interactive_edit) ->
    increment_stat(Db, {couchdb, database_writes}),
    AllOrNothing = lists:member(all_or_nothing, Options),
    % go ahead and generate the new revision ids for the documents.
    % separate out the NonRep documents from the rest of the documents
    {Docs2, NonRepDocs} = lists:foldl(
        fun(#doc{id=Id}=Doc, {DocsAcc, NonRepDocsAcc}) ->
            case Id of
            <<?LOCAL_DOC_PREFIX, _/binary>> ->
                {DocsAcc, [Doc | NonRepDocsAcc]};
            Id->
                {[Doc | DocsAcc], NonRepDocsAcc}
            end
        end, {[], []}, Docs),

    DocBuckets = group_alike_docs(Docs2),

    case (Db#db.validate_doc_funs /= []) orelse
        lists:any(
            fun(#doc{id= <<?DESIGN_DOC_PREFIX, _/binary>>}) ->
                true;
            (#doc{atts=Atts}) ->
                Atts /= []
            end, Docs2) of
    true ->
        % lookup the doc by id and get the most recent
        Ids = [Id || [#doc{id=Id}|_] <- DocBuckets],
        ExistingDocInfos = get_full_doc_infos(Db, Ids),

        {DocBucketsPrepped, PreCommitFailures} = prep_and_validate_updates(Db,
                DocBuckets, ExistingDocInfos, AllOrNothing, [], []),

        % strip out any empty buckets
        DocBuckets2 = [Bucket || [_|_] = Bucket <- DocBucketsPrepped];
    false ->
        PreCommitFailures = [],
        DocBuckets2 = DocBuckets
    end,

    if (AllOrNothing) and (PreCommitFailures /= []) ->
        {aborted, lists:map(
            fun({{Id,{Pos, [RevId|_]}}, Error}) ->
                {{Id, {Pos, RevId}}, Error};
            ({{Id,{0, []}}, Error}) ->
                {{Id, {0, <<>>}}, Error}
            end, PreCommitFailures)};
    true ->
        Options2 = if AllOrNothing -> [merge_conflicts];
                true -> [] end ++ Options,
        DocBuckets3 = [[
                doc_flush_atts(set_new_att_revpos(
                        check_dup_atts(Doc)), Db#db.fd)
                || Doc <- B] || B <- DocBuckets2],
        {DocBuckets4, IdRevs} = new_revs(DocBuckets3, [], []),

        {ok, CommitResults} = write_and_commit(Db, DocBuckets4, NonRepDocs, Options2),

        ResultsDict = dict:from_list(IdRevs ++ CommitResults ++ PreCommitFailures),
        {ok, lists:map(
            fun(#doc{id=Id,revs={Pos, RevIds}}) ->
                {ok, Result} = dict:find({Id, {Pos, RevIds}}, ResultsDict),
                Result
            end, Docs)}
    end.

% Returns the first available document on disk. Input list is a full rev path
% for the doc.
make_first_doc_on_disk(_Db, _Id, _Pos, []) ->
    nil;
make_first_doc_on_disk(Db, Id, Pos, [{_Rev, #doc{}} | RestPath]) ->
    make_first_doc_on_disk(Db, Id, Pos-1, RestPath);
make_first_doc_on_disk(Db, Id, Pos, [{_Rev, ?REV_MISSING}|RestPath]) ->
    make_first_doc_on_disk(Db, Id, Pos - 1, RestPath);
make_first_doc_on_disk(Db, Id, Pos, [{_, #leaf{deleted=IsDel, ptr=Sp}} |_]=DocPath) ->
    Revs = [Rev || {Rev, _} <- DocPath],
    make_doc(Db, Id, IsDel, Sp, {Pos, Revs}).

set_commit_option(Options) ->
    CommitSettings = {
        [true || O <- Options, O==full_commit orelse O==delay_commit],
        couch_config:get("couchdb", "delayed_commits", "false")
    },
    case CommitSettings of
    {[true], _} ->
        Options; % user requested explicit commit setting, do not change it
    {_, "true"} ->
        Options; % delayed commits are enabled, do nothing
    {_, "false"} ->
        [full_commit|Options];
    {_, Else} ->
        ?LOG_ERROR("[couchdb] delayed_commits setting must be true/false, not ~p",
            [Else]),
        [full_commit|Options]
    end.

collect_results(Pid, MRef, ResultsAcc) ->
    receive
    {result, Pid, Result} ->
        collect_results(Pid, MRef, [Result | ResultsAcc]);
    {done, Pid} ->
        {ok, ResultsAcc};
    {retry, Pid} ->
        retry;
    {'DOWN', MRef, _, _, Reason} ->
        exit(Reason)
    end.

write_and_commit(#db{main_pid=Pid, user_ctx=Ctx}=Db, DocBuckets,
        NonRepDocs, Options0) ->
    Options = set_commit_option(Options0),
    MergeConflicts = lists:member(merge_conflicts, Options),
    FullCommit = lists:member(full_commit, Options),
    MRef = erlang:monitor(process, Pid),
    try
        Pid ! {update_docs, self(), DocBuckets, NonRepDocs, MergeConflicts, FullCommit},
        case collect_results(Pid, MRef, []) of
        {ok, Results} -> {ok, Results};
        retry ->
            % This can happen if the db file we wrote to was swapped out by
            % compaction. Retry by reopening the db and writing to the current file
            {ok, Db2} = open(Db#db.name, [{user_ctx, Ctx}]),
            DocBuckets2 = [[doc_flush_atts(Doc, Db2#db.fd) || Doc <- Bucket] || Bucket <- DocBuckets],
            % We only retry once
            close(Db2),
            Pid ! {update_docs, self(), DocBuckets2, NonRepDocs, MergeConflicts, FullCommit},
            case collect_results(Pid, MRef, []) of
            {ok, Results} -> {ok, Results};
            retry -> throw({update_error, compaction_retry})
            end
        end
    after
        erlang:demonitor(MRef, [flush])
    end.


set_new_att_revpos(#doc{revs={RevPos,_Revs},atts=Atts}=Doc) ->
    Doc#doc{atts= lists:map(fun(#att{data={_Fd,_Sp}}=Att) ->
            % already commited to disk, do not set new rev
            Att;
        (Att) ->
            Att#att{revpos=RevPos+1}
        end, Atts)}.


doc_flush_atts(Doc, Fd) ->
    Doc#doc{atts=[flush_att(Fd, Att) || Att <- Doc#doc.atts]}.

check_md5(_NewSig, <<>>) -> ok;
check_md5(Sig, Sig) -> ok;
check_md5(_, _) -> throw(md5_mismatch).

flush_att(Fd, #att{data={Fd0, _}}=Att) when Fd0 == Fd ->
    % already written to our file, nothing to write
    Att;

flush_att(Fd, #att{data={OtherFd,StreamPointer}, md5=InMd5,
    disk_len=InDiskLen} = Att) ->
    {NewStreamData, Len, _IdentityLen, Md5, IdentityMd5} =
            couch_stream:copy_to_new_stream(OtherFd, StreamPointer, Fd),
    check_md5(IdentityMd5, InMd5),
    Att#att{data={Fd, NewStreamData}, md5=Md5, att_len=Len, disk_len=InDiskLen};

flush_att(Fd, #att{data=Data}=Att) when is_binary(Data) ->
    with_stream(Fd, Att, fun(OutputStream) ->
        couch_stream:write(OutputStream, Data)
    end);

flush_att(Fd, #att{data=Fun,att_len=undefined}=Att) when is_function(Fun) ->
    with_stream(Fd, Att, fun(OutputStream) ->
        % Fun(MaxChunkSize, WriterFun) must call WriterFun
        % once for each chunk of the attachment,
        Fun(4096,
            % WriterFun({Length, Binary}, State)
            % WriterFun({0, _Footers}, State)
            % Called with Length == 0 on the last time.
            % WriterFun returns NewState.
            fun({0, Footers}, _) ->
                F = mochiweb_headers:from_binary(Footers),
                case mochiweb_headers:get_value("Content-MD5", F) of
                undefined ->
                    ok;
                Md5 ->
                    {md5, base64:decode(Md5)}
                end;
            ({_Length, Chunk}, _) ->
                couch_stream:write(OutputStream, Chunk)
            end, ok)
    end);

flush_att(Fd, #att{data=Fun,att_len=AttLen}=Att) when is_function(Fun) ->
    with_stream(Fd, Att, fun(OutputStream) ->
        write_streamed_attachment(OutputStream, Fun, AttLen)
    end).

% From RFC 2616 3.6.1 - Chunked Transfer Coding
%
%   In other words, the origin server is willing to accept
%   the possibility that the trailer fields might be silently
%   discarded along the path to the client.
%
% I take this to mean that if "Trailers: Content-MD5\r\n"
% is present in the request, but there is no Content-MD5
% trailer, we're free to ignore this inconsistency and
% pretend that no Content-MD5 exists.
with_stream(Fd, #att{md5=InMd5,type=Type,encoding=Enc}=Att, Fun) ->
    {ok, OutputStream} = case (Enc =:= identity) andalso
        couch_util:compressible_att_type(Type) of
    true ->
        CompLevel = list_to_integer(
            couch_config:get("attachments", "compression_level", "0")
        ),
        couch_stream:open(Fd, gzip, [{compression_level, CompLevel}]);
    _ ->
        couch_stream:open(Fd)
    end,
    ReqMd5 = case Fun(OutputStream) of
        {md5, FooterMd5} ->
            case InMd5 of
                md5_in_footer -> FooterMd5;
                _ -> InMd5
            end;
        _ ->
            InMd5
    end,
    {StreamInfo, Len, IdentityLen, Md5, IdentityMd5} =
        couch_stream:close(OutputStream),
    check_md5(IdentityMd5, ReqMd5),
    {AttLen, DiskLen, NewEnc} = case Enc of
    identity ->
        case {Md5, IdentityMd5} of
        {Same, Same} ->
            {Len, IdentityLen, identity};
        _ ->
            {Len, IdentityLen, gzip}
        end;
    gzip ->
        case {Att#att.att_len, Att#att.disk_len} of
        {AL, DL} when AL =:= undefined orelse DL =:= undefined ->
            % Compressed attachment uploaded through the standalone API.
            {Len, Len, gzip};
        {AL, DL} ->
            % This case is used for efficient push-replication, where a
            % compressed attachment is located in the body of multipart
            % content-type request.
            {AL, DL, gzip}
        end
    end,
    Att#att{
        data={Fd,StreamInfo},
        att_len=AttLen,
        disk_len=DiskLen,
        md5=Md5,
        encoding=NewEnc
    }.


write_streamed_attachment(_Stream, _F, 0) ->
    ok;
write_streamed_attachment(Stream, F, LenLeft) when LenLeft > 0 ->
    Bin = read_next_chunk(F, LenLeft),
    ok = couch_stream:write(Stream, Bin),
    write_streamed_attachment(Stream, F, LenLeft - size(Bin)).

read_next_chunk(F, _) when is_function(F, 0) ->
    F();
read_next_chunk(F, LenLeft) when is_function(F, 1) ->
    F(lists:min([LenLeft, 16#2000])).

enum_docs_since_reduce_to_count(Reds) ->
    couch_btree:final_reduce(
            fun couch_db_updater:btree_by_seq_reduce/2, Reds).

enum_docs_reduce_to_count(Reds) ->
    {Count, _, _} = couch_btree:final_reduce(
            fun couch_db_updater:btree_by_id_reduce/2, Reds),
    Count.

changes_since(Db, StartSeq, Fun, Acc) ->
    changes_since(Db, StartSeq, Fun, [], Acc).

changes_since(Db, StartSeq, Fun, Options, Acc) ->
    Wrapper = fun(FullDocInfo, _Offset, Acc2) ->
            case FullDocInfo of
            #full_doc_info{} ->
                DocInfo = couch_doc:to_doc_info(FullDocInfo);
            #doc_info{} ->
                DocInfo = FullDocInfo
            end,
            Fun(DocInfo, Acc2)
        end,
    {ok, _LastReduction, AccOut} = couch_btree:fold(Db#db.seq_tree, Wrapper,
        Acc, [{start_key, couch_util:to_integer(StartSeq) + 1} | Options]),
    {ok, AccOut}.

count_changes_since(Db, SinceSeq) ->
    {ok, Changes} =
    couch_btree:fold_reduce(Db#db.seq_tree,
        fun(_SeqStart, PartialReds, 0) ->
            {ok, couch_btree:final_reduce(Db#db.seq_tree, PartialReds)}
        end,
        0, [{start_key, SinceSeq + 1}]),
    Changes.

enum_docs_since(Db, SinceSeq, InFun, Acc, Options) ->
    {ok, LastReduction, AccOut} = couch_btree:fold(Db#db.seq_tree, InFun, Acc, [{start_key, SinceSeq + 1} | Options]),
    {ok, enum_docs_since_reduce_to_count(LastReduction), AccOut}.

enum_docs(Db, InFun, InAcc, Options) ->
    {ok, LastReduce, OutAcc} = couch_view:fold(
        #view{btree=Db#db.id_tree}, InFun, InAcc, Options),
    {ok, enum_docs_reduce_to_count(LastReduce), OutAcc}.

%%% Internal function %%%
open_doc_revs_int(Db, IdRevs, Options) ->
    Ids = [Id || {Id, _Revs} <- IdRevs],
    LookupResults = get_full_doc_infos(Db, Ids),
    lists:zipwith(
        fun({Id, Revs}, Lookup) ->
            case Lookup of
            {ok, #full_doc_info{rev_tree=RevTree}} ->
                {FoundRevs, MissingRevs} =
                case Revs of
                all ->
                    {couch_key_tree:get_all_leafs(RevTree), []};
                _ ->
                    case lists:member(latest, Options) of
                    true ->
                        couch_key_tree:get_key_leafs(RevTree, Revs);
                    false ->
                        couch_key_tree:get(RevTree, Revs)
                    end
                end,
                FoundResults =
                lists:map(fun({Value, {Pos, [Rev|_]}=FoundRevPath}) ->
                    case Value of
                    ?REV_MISSING ->
                        % we have the rev in our list but know nothing about it
                        {{not_found, missing}, {Pos, Rev}};
                    #leaf{deleted=IsDeleted, ptr=SummaryPtr} ->
                        {ok, make_doc(Db, Id, IsDeleted, SummaryPtr, FoundRevPath)}
                    end
                end, FoundRevs),
                Results = FoundResults ++ [{{not_found, missing}, MissingRev} || MissingRev <- MissingRevs],
                {ok, Results};
            not_found when Revs == all ->
                {ok, []};
            not_found ->
                {ok, [{{not_found, missing}, Rev} || Rev <- Revs]}
            end
        end,
        IdRevs, LookupResults).

open_doc_int(Db, <<?LOCAL_DOC_PREFIX, _/binary>> = Id, _Options) ->
    case couch_btree:lookup(Db#db.local_tree, [Id]) of
    [{ok, {_, {Rev, BodyData}}}] ->
        {ok, #doc{id=Id, revs={0, [list_to_binary(integer_to_list(Rev))]}, body=BodyData}};
    [not_found] ->
        {not_found, missing}
    end;
open_doc_int(Db, #doc_info{id=Id,revs=[RevInfo|_]}=DocInfo, Options) ->
    #rev_info{deleted=IsDeleted,rev={Pos,RevId},body_sp=Bp} = RevInfo,
    Doc = make_doc(Db, Id, IsDeleted, Bp, {Pos,[RevId]}),
    {ok, Doc#doc{meta=doc_meta_info(DocInfo, [], Options)}};
open_doc_int(Db, #full_doc_info{id=Id,rev_tree=RevTree}=FullDocInfo, Options) ->
    #doc_info{revs=[#rev_info{deleted=IsDeleted,rev=Rev,body_sp=Bp}|_]} =
        DocInfo = couch_doc:to_doc_info(FullDocInfo),
    {[{_, RevPath}], []} = couch_key_tree:get(RevTree, [Rev]),
    Doc = make_doc(Db, Id, IsDeleted, Bp, RevPath),
    {ok, Doc#doc{meta=doc_meta_info(DocInfo, RevTree, Options)}};
open_doc_int(Db, Id, Options) ->
    case get_full_doc_info(Db, Id) of
    {ok, FullDocInfo} ->
        open_doc_int(Db, FullDocInfo, Options);
    not_found ->
        {not_found, missing}
    end.

doc_meta_info(#doc_info{high_seq=Seq,revs=[#rev_info{rev=Rev}|RestInfo]}, RevTree, Options) ->
    case lists:member(revs_info, Options) of
    false -> [];
    true ->
        {[{Pos, RevPath}],[]} =
            couch_key_tree:get_full_key_paths(RevTree, [Rev]),

        [{revs_info, Pos, lists:map(
            fun({Rev1, #leaf{deleted=true}}) ->
                {Rev1, deleted};
            ({Rev1, #leaf{deleted=false}}) ->
                {Rev1, available};
            ({Rev1, ?REV_MISSING}) ->
                {Rev1, missing}
            end, RevPath)}]
    end ++
    case lists:member(conflicts, Options) of
    false -> [];
    true ->
        case [Rev1 || #rev_info{rev=Rev1,deleted=false} <- RestInfo] of
        [] -> [];
        ConflictRevs -> [{conflicts, ConflictRevs}]
        end
    end ++
    case lists:member(deleted_conflicts, Options) of
    false -> [];
    true ->
        case [Rev1 || #rev_info{rev=Rev1,deleted=true} <- RestInfo] of
        [] -> [];
        DelConflictRevs -> [{deleted_conflicts, DelConflictRevs}]
        end
    end ++
    case lists:member(local_seq, Options) of
    false -> [];
    true -> [{local_seq, Seq}]
    end.

read_doc(#db{fd=Fd}, OldStreamPointer) when is_tuple(OldStreamPointer) ->
    % 09 UPGRADE CODE
    couch_stream:old_read_term(Fd, OldStreamPointer);
read_doc(#db{fd=Fd}, Pos) ->
    couch_file:pread_term(Fd, Pos).


doc_to_tree(#doc{revs={Start, RevIds}}=Doc) ->
    [Tree] = doc_to_tree_simple(Doc, lists:reverse(RevIds)),
    {Start - length(RevIds) + 1, Tree}.


doc_to_tree_simple(Doc, [RevId]) ->
    [{RevId, Doc, []}];
doc_to_tree_simple(Doc, [RevId | Rest]) ->
    [{RevId, ?REV_MISSING, doc_to_tree_simple(Doc, Rest)}].


make_doc(#db{fd=Fd}=Db, Id, Deleted, Bp, RevisionPath) ->
    {BodyData, Atts} =
    case Bp of
    nil ->
        {[], []};
    _ ->
        {ok, {BodyData0, Atts0}} = read_doc(Db, Bp),
        {BodyData0,
            lists:map(
                fun({Name,Type,Sp,AttLen,DiskLen,RevPos,Md5,Enc}) ->
                    #att{name=Name,
                        type=Type,
                        att_len=AttLen,
                        disk_len=DiskLen,
                        md5=Md5,
                        revpos=RevPos,
                        data={Fd,Sp},
                        encoding=
                            case Enc of
                            true ->
                                % 0110 UPGRADE CODE
                                gzip;
                            false ->
                                % 0110 UPGRADE CODE
                                identity;
                            _ ->
                                Enc
                            end
                    };
                ({Name,Type,Sp,AttLen,RevPos,Md5}) ->
                    #att{name=Name,
                        type=Type,
                        att_len=AttLen,
                        disk_len=AttLen,
                        md5=Md5,
                        revpos=RevPos,
                        data={Fd,Sp}};
                ({Name,{Type,Sp,AttLen}}) ->
                    #att{name=Name,
                        type=Type,
                        att_len=AttLen,
                        disk_len=AttLen,
                        md5= <<>>,
                        revpos=0,
                        data={Fd,Sp}}
                end, Atts0)}
    end,
    #doc{
        id = Id,
        revs = RevisionPath,
        body = BodyData,
        atts = Atts,
        deleted = Deleted
        }.


increment_stat(#db{is_sys_db = true}, _Stat) ->
    ok;
increment_stat(#db{}, Stat) ->
    couch_stats_collector:increment(Stat).