summaryrefslogtreecommitdiffstats
path: root/toolkit/components/places/PlacesTransactions.sys.mjs
blob: 0c9accd3bab017df88534ced26b735b34018ddaa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/**
 * Overview
 * --------
 * This modules serves as the transactions manager for Places (hereinafter PTM).
 * It implements all the elementary transactions for its UI commands: creating
 * items, editing their various properties, and so forth.
 *
 * Note that since the effect of invoking a Places command is not limited to the
 * window in which it was performed (e.g. a folder created in the Library may be
 * the parent of a bookmark created in some browser window), PTM is a singleton.
 * It's therefore unnecessary to initialize PTM in any way apart importing this
 * module.
 *
 * PTM shares most of its semantics with common command pattern implementations.
 * However, the asynchronous design of contemporary and future APIs, combined
 * with the commitment to serialize all UI operations, does make things a little
 * bit different.  For example, when |undo| is called in order to undo the top
 * undo entry, the caller cannot tell for sure what entry would it be, because
 * the execution of some transactions is either in process, or enqueued to be.
 *
 * Also note that unlike the nsITransactionManager, for example, this API is by
 * no means generic.  That is, it cannot be used to execute anything but the
 * elementary transactions implemented here (Please file a bug if you find
 * anything uncovered).  More-complex transactions (e.g. creating a folder and
 * moving a bookmark into it) may be implemented as a batch (see below).
 *
 * A note about GUIDs and item-ids
 * -------------------------------
 * There's an ongoing effort (see bug 1071511) to deprecate item-ids in Places
 * in favor of GUIDs.  Both because new APIs (e.g. Bookmark.jsm) expose them to
 * the minimum necessary, and because GUIDs play much better with implementing
 * |redo|, this API doesn't support item-ids at all, and only accepts bookmark
 * GUIDs, both for input (e.g. for setting the parent folder for a new bookmark)
 * and for output (when the GUID for such a bookmark is propagated).
 *
 * Constructing transactions
 * -------------------------
 * At the bottom of this module you will find transactions for all Places UI
 * commands.  They are exposed as constructors set on the PlacesTransactions
 * object (e.g. PlacesTransactions.NewFolder).  The input for this constructors
 * is taken in the form of a single argument, a plain object consisting of the
 * properties for the transaction.  Input properties may be either required or
 * optional (for example, |keyword| is required for the EditKeyword transaction,
 * but optional for the NewBookmark transaction).
 *
 * To make things simple, a given input property has the same basic meaning and
 * valid values across all transactions which accept it in the input object.
 * Here is a list of all supported input properties along with their expected
 * values:
 *  - url: a URL object, an nsIURI object, or a href.
 *  - urls: an array of urls, as above.
 *  - tag - a string.
 *  - tags: an array of strings.
 *  - guid, parentGuid, newParentGuid: a valid Places GUID string.
 *  - guids: an array of valid Places GUID strings.
 *  - title: a string
 *  - index, newIndex: the position of an item in its containing folder,
 *    starting from 0.
 *    integer and PlacesUtils.bookmarks.DEFAULT_INDEX
 *
 * If a required property is missing in the input object (e.g. not specifying
 * parentGuid for NewBookmark), or if the value for any of the input properties
 * is invalid "on the surface" (e.g. a numeric value for GUID, or a string that
 * isn't 12-characters long), the transaction constructor throws right way.
 * More complex errors (e.g. passing a non-existent GUID for parentGuid) only
 * reveal once the transaction is executed.
 *
 * Executing Transactions (the |transact| method of transactions)
 * --------------------------------------------------------------
 * Once a transaction is created, you must call its |transact| method for it to
 * be executed and take effect.  |transact| is an asynchronous method that takes
 * no arguments, and returns a promise that resolves once the transaction is
 * executed.  Executing one of the transactions for creating items (NewBookmark,
 * NewFolder, NewSeparator) resolve to the new item's GUID.
 * There's no resolution value for other transactions.
 * If a transaction fails to execute, |transact| rejects and the transactions
 * history is not affected.
 *
 * |transact| throws if it's called more than once (successfully or not) on the
 * same transaction object.
 *
 * Batches
 * -------
 * Sometimes it is useful to "batch" or "merge" transactions.  For example,
 * something like "Bookmark All Tabs" may be implemented as one NewFolder
 * transaction followed by numerous NewBookmark transactions - all to be undone
 * or redone in a single undo or redo command.  Use `PlacesTransactions.batch()`
 * in such cases.
 * It takes an array of transactions which will be executed in the given order
 * and later be treated as a single entry in the transactions history.
 * If a transaction depends on the results from a previous one, it can be
 * replaced by a function that will be invoked with an array of results
 * accumulated from the previous transactions, indexed in the same positions.
 * The function should return the transaction to execute. For example:
 *
 *  let transactions = [
 *    // Returns the GUID of the new bookmark.
 *    PlacesTransactions.NewBookmark({
 *      parentGuid: "someGUID",
 *      title: "someTitle",
 *      url: "https://www.mozilla.org/""
 *    }),
 *    previousResults => PlacesTransactions.EditKeyword({
 *      // Get the GUID from the result of transactions[0].
 *      guid: previousResults[0],
 *      keyword: "someKeyword",
 *    },
 *  ];
 *
 * `PlacesTransactions.batch()` returns a promise resolved when the batch ends.
 * The resolution value is an array with all the transaction return values
 * indexed like the original transactions. So, for example, if a transaction
 * returns an array of GUIDs, to get a list of all the created GUIDs for all the
 * transactions one could use .flat() to flatten the array.
 *
 * If any transactions fails to execute, the batch continues (exceptions are
 * logged) and the result of that transactions will be set to undefined.
 * Only transactions that were executed successfully are added to the
 * transactions history as part of the batch.
 *
 * Serialization
 * -------------
 * All |PlacesTransaction| operations are serialized.  That is, even though the
 * implementation is asynchronous, the order in which PlacesTransactions methods
 * is called does guarantee the order in which they are to be invoked.
 *
 * The only exception to this rule is |transact| calls done during a batch (see
 * above).  |transact| calls are serialized with each other (and with undo, redo
 * and clearTransactionsHistory), but they  are, of course, not serialized with
 * batches.
 *
 * The transactions-history structure
 * ----------------------------------
 * The transactions-history is a two-dimensional stack of transactions: the
 * transactions are ordered in reverse to the order they were committed.
 * It's two-dimensional because PTM allows batching transactions together for
 * the purpose of undo or redo (see Batches above).
 *
 * The undoPosition property is set to the index of the top entry. If there is
 * no entry at that index, there is nothing to undo.
 * Entries prior to undoPosition, if any, are redo entries, the first one being
 * the top redo entry.
 *
 * [ [2nd redo txn, 1st redo txn],  <= 2nd redo entry
 *   [2nd redo txn, 1st redo txn],  <= 1st redo entry
 *   [1st undo txn, 2nd undo txn],  <= 1st undo entry
 *   [1st undo txn, 2nd undo txn]   <= 2nd undo entry ]
 * undoPostion: 2.
 *
 * Note that when a new entry is created, all redo entries are removed.
 */

const TRANSACTIONS_QUEUE_TIMEOUT_MS = 240000; // 4 Mins.

import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";

// Use a single queue bookmarks transaction manager. This pref exists as an
// emergency switch-off, it will go away in the future.
const prefs = {};
XPCOMUtils.defineLazyPreferenceGetter(
  prefs,
  "USE_SINGLE_QUEUE",
  "places.bookmarks.useSingleQueueTransactionManager",
  true
);

import { PlacesUtils } from "resource://gre/modules/PlacesUtils.sys.mjs";

function setTimeout(callback, ms) {
  let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
  timer.initWithCallback(callback, ms, timer.TYPE_ONE_SHOT);
}

const lazy = {};
ChromeUtils.defineLazyGetter(lazy, "logger", function () {
  return console.createInstance({
    prefix: "PlacesTransactions",
    maxLogLevel: Services.prefs.getCharPref(
      "places.transactions.logLevel",
      "Error"
    ),
  });
});

class TransactionsHistoryArray extends Array {
  constructor() {
    super();

    // The index of the first undo entry (if any) - See the documentation
    // at the top of this file.
    this._undoPosition = 0;
    // Outside of this module, the API of transactions is inaccessible, and so
    // are any internal properties.  To achieve that, transactions are proxified
    // in their constructors.  This maps the proxies to their respective raw
    // objects.
    this.proxifiedToRaw = new WeakMap();
  }

  get undoPosition() {
    return this._undoPosition;
  }

  // Handy shortcuts
  get topUndoEntry() {
    return this.undoPosition < this.length ? this[this.undoPosition] : null;
  }
  get topRedoEntry() {
    return this.undoPosition > 0 ? this[this.undoPosition - 1] : null;
  }

  /**
   * Proxify a transaction object for consumers.
   * @param rawTransaction
   *        the raw transaction object.
   * @return the proxified transaction object.
   * @see getRawTransaction for retrieving the raw transaction.
   */
  proxifyTransaction(rawTransaction) {
    let proxy = Object.freeze({
      transact(inBatch, batchIndex) {
        return TransactionsManager.transact(this, inBatch, batchIndex);
      },
      toString() {
        return rawTransaction.toString();
      },
    });
    this.proxifiedToRaw.set(proxy, rawTransaction);
    return proxy;
  }

  /**
   * Check if the given object is a the proxy object for some transaction.
   * @param aValue
   *        any JS value.
   * @return true if aValue is the proxy object for some transaction, false
   * otherwise.
   */
  isProxifiedTransactionObject(value) {
    return this.proxifiedToRaw.has(value);
  }

  /**
   * Get the raw transaction for the given proxy.
   * @param aProxy
   *        the proxy object
   * @return the transaction proxified by aProxy; |undefined| is returned if
   * aProxy is not a proxified transaction.
   */
  getRawTransaction(proxy) {
    return this.proxifiedToRaw.get(proxy);
  }

  /**
   * Add a transaction either as a new entry, if forced or if there are no undo
   * entries, or to the top undo entry.
   *
   * @param aProxifiedTransaction
   *        the proxified transaction object to be added to the transaction
   *        history.
   * @param [optional] aForceNewEntry
   *        Force a new entry for the transaction. Default: false.
   *        If false, an entry will we created only if there's no undo entry
   *        to extend.
   */
  add(proxifiedTransaction, forceNewEntry = false) {
    if (!this.isProxifiedTransactionObject(proxifiedTransaction)) {
      throw new Error("aProxifiedTransaction is not a proxified transaction");
    }

    if (!this.length || forceNewEntry) {
      this.clearRedoEntries();
      lazy.logger.debug(`Adding transaction: ${proxifiedTransaction}`);
      this.unshift([proxifiedTransaction]);
    } else {
      lazy.logger.debug(`Adding transaction: ${proxifiedTransaction}`);
      this[this.undoPosition].unshift(proxifiedTransaction);
    }
  }

  /**
   * Clear all undo entries.
   */
  clearUndoEntries() {
    lazy.logger.debug("Clearing undo entries");
    if (this.undoPosition < this.length) {
      this.splice(this.undoPosition);
    }
  }

  /**
   * Clear all redo entries.
   */
  clearRedoEntries() {
    lazy.logger.debug("Clearing redo entries");
    if (this.undoPosition > 0) {
      this.splice(0, this.undoPosition);
      this._undoPosition = 0;
    }
  }

  /**
   * Clear all entries.
   */
  clearAllEntries() {
    lazy.logger.debug("Clearing all entries");
    if (this.length) {
      this.splice(0);
      this._undoPosition = 0;
    }
  }
}

ChromeUtils.defineLazyGetter(
  lazy,
  "TransactionsHistory",
  () => new TransactionsHistoryArray()
);

export var PlacesTransactions = {
  /**
   * @see Batches in the module documentation.
   */
  batch(transactionsToBatch, batchName) {
    if (!Array.isArray(transactionsToBatch) || !transactionsToBatch.length) {
      throw new Error("Must pass a non-empty array");
    }
    if (
      transactionsToBatch.some(
        o =>
          !lazy.TransactionsHistory.isProxifiedTransactionObject(o) &&
          typeof o != "function"
      )
    ) {
      throw new Error("Must pass only transactions or functions");
    }
    lazy.logger.debug(
      `Batch ${batchName}: ${transactionsToBatch.length} transactions`
    );
    return TransactionsManager.batch(async function () {
      lazy.logger.debug(`Batch ${batchName}: executing transactions`);
      let accumulatedResults = [];
      for (let txn of transactionsToBatch) {
        try {
          if (typeof txn == "function") {
            txn = txn(accumulatedResults);
          }
          accumulatedResults.push(
            await txn.transact(true, accumulatedResults.length)
          );
        } catch (ex) {
          // TODO Bug 1865631: handle these errors better, currently we just
          // continue, that works for non-dependent transactions, but will
          // skip most of the work for functions depending on previous results.
          // Moreover in both cases we should notify the user about the problem.
          accumulatedResults.push(undefined);
          // Using console.error() here sometimes fails, due to unknown XPC
          // wrappers reasons, so just use our logger.
          lazy.logger.error(`Failed to execute batched transaction: ${ex}`);
        }
      }
      return accumulatedResults;
    });
  },

  /**
   * Asynchronously undo the transaction immediately after the current undo
   * position in the transactions history in the reverse order, if any, and
   * adjusts the undo position.
   *
   * @return {Promises).  The promise always resolves.
   * @note All undo manager operations are queued. This means that transactions
   * history may change by the time your request is fulfilled.
   */
  undo() {
    lazy.logger.debug("undo() was invoked");
    return TransactionsManager.undo();
  },

  /**
   * Asynchronously redo the transaction immediately before the current undo
   * position in the transactions history, if any, and adjusts the undo
   * position.
   *
   * @return {Promises).  The promise always resolves.
   * @note All undo manager operations are queued. This means that transactions
   * history may change by the time your request is fulfilled.
   */
  redo() {
    lazy.logger.debug("redo() was invoked");
    return TransactionsManager.redo();
  },

  /**
   * Asynchronously clear the undo, redo, or all entries from the transactions
   * history.
   *
   * @param [optional] undoEntries
   *        Whether or not to clear undo entries.  Default: true.
   * @param [optional] redoEntries
   *        Whether or not to clear undo entries.  Default: true.
   *
   * @return {Promises).  The promise always resolves.
   * @throws if both aUndoEntries and aRedoEntries are false.
   * @note All undo manager operations are queued. This means that transactions
   * history may change by the time your request is fulfilled.
   */
  clearTransactionsHistory(undoEntries = true, redoEntries = true) {
    lazy.logger.debug("clearTransactionsHistory() was invoked");
    return TransactionsManager.clearTransactionsHistory(
      undoEntries,
      redoEntries
    );
  },

  /**
   * The numbers of entries in the transactions history.
   */
  get length() {
    return lazy.TransactionsHistory.length;
  },

  /**
   * Get the transaction history entry at a given index.  Each entry consists
   * of one or more transaction objects.
   *
   * @param index
   *        the index of the entry to retrieve.
   * @return an array of transaction objects in their undo order (that is,
   * reversely to the order they were executed).
   * @throw if aIndex is invalid (< 0 or >= length).
   * @note the returned array is a clone of the history entry and is not
   * kept in sync with the original entry if it changes.
   */
  entry(index) {
    if (!Number.isInteger(index) || index < 0 || index >= this.length) {
      throw new Error("Invalid index");
    }

    return lazy.TransactionsHistory[index];
  },

  /**
   * The index of the top undo entry in the transactions history.
   * If there are no undo entries, it equals to |length|.
   * Entries past this point
   * Entries at and past this point are redo entries.
   */
  get undoPosition() {
    return lazy.TransactionsHistory.undoPosition;
  },

  /**
   * Shortcut for accessing the top undo entry in the transaction history.
   */
  get topUndoEntry() {
    return lazy.TransactionsHistory.topUndoEntry;
  },

  /**
   * Shortcut for accessing the top redo entry in the transaction history.
   */
  get topRedoEntry() {
    return lazy.TransactionsHistory.topRedoEntry;
  },
};

/**
 * Helper for serializing the calls to TransactionsManager methods. It allows
 * us to guarantee that the order in which TransactionsManager asynchronous
 * methods are called also enforces the order in which they're executed, and
 * that they are never executed in parallel.
 *
 * In other words: Enqueuer.enqueue(aFunc1); Enqueuer.enqueue(aFunc2) is roughly
 * the same as Task.spawn(aFunc1).then(Task.spawn(aFunc2)).
 */
function Enqueuer(name) {
  this._promise = Promise.resolve();
  this._name = name;
}
Enqueuer.prototype = {
  /**
   * Spawn a functions once all previous functions enqueued are done running,
   * and all promises passed to alsoWaitFor are no longer pending.
   *
   * @param   func
   *          a function returning a promise.
   * @return  a promise that resolves once aFunc is done running. The promise
   *          "mirrors" the promise returned by aFunc.
   */
  enqueue(func) {
    lazy.logger.debug(`${this._name} enqueing`);
    // If a transaction awaits on a never resolved promise, or is mistakenly
    // nested, it could hang the transactions queue forever.  Thus we timeout
    // the execution after a meaningful amount of time, to ensure in any case
    // we'll proceed after a while.
    let timeoutPromise = new Promise((resolve, reject) => {
      setTimeout(
        () =>
          reject(
            new Error(
              "PlacesTransaction timeout, most likely caused by unresolved pending work."
            )
          ),
        TRANSACTIONS_QUEUE_TIMEOUT_MS
      );
    });
    let promise = this._promise.then(() =>
      Promise.race([func(), timeoutPromise])
    );

    // Propagate exceptions to the caller, but dismiss them internally.
    this._promise = promise.catch(lazy.logger.error);
    return promise;
  },

  /**
   * Same as above, but for a promise returned by a function that already run.
   * This is useful, for example, for serializing transact calls with undo calls,
   * even though transact has its own Enqueuer.
   *
   * @param {Promise} otherPromise
   *        any promise.
   * @param {string} source
   *        source for logging purposes
   */
  alsoWaitFor(otherPromise, source) {
    lazy.logger.debug(`${this._name} alsoWaitFor: ${source}`);
    // We don't care if aPromise resolves or rejects, but just that is not
    // pending anymore.
    // If a transaction awaits on a never resolved promise, or is mistakenly
    // nested, it could hang the transactions queue forever.  Thus we timeout
    // the execution after a meaningful amount of time, to ensure in any case
    // we'll proceed after a while.
    let timeoutPromise = new Promise((resolve, reject) => {
      setTimeout(
        () =>
          reject(
            new Error(
              "PlacesTransaction timeout, most likely caused by unresolved pending work."
            )
          ),
        TRANSACTIONS_QUEUE_TIMEOUT_MS
      );
    });
    let promise = Promise.race([otherPromise, timeoutPromise]).catch(
      console.error
    );
    this._promise = Promise.all([this._promise, promise]);
  },

  /**
   * The promise for this queue.
   */
  get promise() {
    return this._promise;
  },
};

var TransactionsManager = {
  // See the documentation at the top of this file. |transact| calls are not
  // serialized with |batch| calls.
  _mainEnqueuer: new Enqueuer("MainEnqueuer"),
  _transactEnqueuer: new Enqueuer("TransactEnqueuer"),

  // Transactions object should never be recycled (that is, |execute| should
  // only be called once (or not at all) after they're constructed.
  // This keeps track of all transactions which were executed.
  _executedTransactions: new WeakSet(),

  /**
   * Execute a proxified transaction.
   *
   * @param {object} txnProxy The proxified transaction to execute.
   * @param {boolean} [inBatch] Whether the transaction is part of a batch.
   * @param {integer} [batchIndex] The index of the transaction in the batch array.
   * @returns {Promise} resolved to the transaction return value once complete.
   */
  transact(txnProxy, inBatch = false, batchIndex = undefined) {
    let rawTxn = lazy.TransactionsHistory.getRawTransaction(txnProxy);
    if (!rawTxn) {
      throw new Error("|transact| was called with an unexpected object");
    }

    if (this._executedTransactions.has(rawTxn)) {
      throw new Error("Transactions objects may not be recycled.");
    }

    lazy.logger.debug(`transact() enqueue: ${txnProxy}`);

    // Add it in advance so one doesn't accidentally do
    // sameTxn.transact(); sameTxn.transact();
    this._executedTransactions.add(rawTxn);

    let task = async () => {
      lazy.logger.debug(`transact execute(): ${txnProxy}`);
      // Don't try to catch exceptions. If execute fails, we better not add the
      // transaction to the undo stack.
      let retval = await rawTxn.execute();

      let forceNewEntry = !inBatch || batchIndex === 0;
      lazy.TransactionsHistory.add(txnProxy, forceNewEntry);

      this._updateCommandsOnActiveWindow();
      return retval;
    };

    if (prefs.USE_SINGLE_QUEUE) {
      return task();
    }

    let promise = this._transactEnqueuer.enqueue(task);
    this._mainEnqueuer.alsoWaitFor(promise, "transact");
    return promise;
  },

  batch(task) {
    return this._mainEnqueuer.enqueue(task);
  },

  /**
   * Undo the top undo entry, if any, and update the undo position accordingly.
   */
  undo() {
    let promise = this._mainEnqueuer.enqueue(async () => {
      lazy.logger.debug("Undo execute");
      let entry = lazy.TransactionsHistory.topUndoEntry;
      if (!entry) {
        return;
      }

      for (let txnProxy of entry) {
        try {
          await lazy.TransactionsHistory.getRawTransaction(txnProxy).undo();
        } catch (ex) {
          // If one transaction is broken, it's not safe to work with any other
          // undo entry.  Report the error and clear the undo history.
          console.error(ex, "Can't undo a transaction, clearing undo entries.");
          lazy.TransactionsHistory.clearUndoEntries();
          return;
        }
      }
      lazy.TransactionsHistory._undoPosition++;
      this._updateCommandsOnActiveWindow();
    });
    if (!prefs.USE_SINGLE_QUEUE) {
      this._transactEnqueuer.alsoWaitFor(promise, "undo");
    }
    return promise;
  },

  /**
   * Redo the top redo entry, if any, and update the undo position accordingly.
   */
  redo() {
    let promise = this._mainEnqueuer.enqueue(async () => {
      lazy.logger.debug("Redo execute");
      let entry = lazy.TransactionsHistory.topRedoEntry;
      if (!entry) {
        return;
      }

      for (let i = entry.length - 1; i >= 0; i--) {
        let transaction = lazy.TransactionsHistory.getRawTransaction(entry[i]);
        try {
          if (transaction.redo) {
            await transaction.redo();
          } else {
            await transaction.execute();
          }
        } catch (ex) {
          // If one transaction is broken, it's not safe to work with any other
          // redo entry. Report the error and clear the undo history.
          console.error(ex, "Can't redo a transaction, clearing redo entries.");
          lazy.TransactionsHistory.clearRedoEntries();
          return;
        }
      }
      lazy.TransactionsHistory._undoPosition--;
      this._updateCommandsOnActiveWindow();
    });
    if (!prefs.USE_SINGLE_QUEUE) {
      this._transactEnqueuer.alsoWaitFor(promise, "redo");
    }
    return promise;
  },

  clearTransactionsHistory(undoEntries, redoEntries) {
    let promise = this._mainEnqueuer.enqueue(function () {
      lazy.logger.debug(`ClearTransactionsHistory execute`);
      if (undoEntries && redoEntries) {
        lazy.TransactionsHistory.clearAllEntries();
      } else if (undoEntries) {
        lazy.TransactionsHistory.clearUndoEntries();
      } else if (redoEntries) {
        lazy.TransactionsHistory.clearRedoEntries();
      } else {
        throw new Error("either aUndoEntries or aRedoEntries should be true");
      }
    });

    if (!prefs.USE_SINGLE_QUEUE) {
      this._transactEnqueuer.alsoWaitFor(promise, "clearTransactionsHistory");
    }
    return promise;
  },

  // Updates commands in the undo group of the active window commands.
  // Inactive windows commands will be updated on focus.
  _updateCommandsOnActiveWindow() {
    // Updating "undo" will cause a group update including "redo".
    try {
      let win = Services.focus.activeWindow;
      if (win) {
        win.updateCommands("undo");
      }
    } catch (ex) {
      console.error(ex, "Couldn't update undo commands.");
    }
  },
};

/**
 * Internal helper for defining the standard transactions and their input.
 * It takes the required and optional properties, and generates the public
 * constructor (which takes the input in the form of a plain object) which,
 * when called, creates the argument-less "public" |execute| method by binding
 * the input properties to the function arguments (required properties first,
 * then the optional properties).
 *
 * If this seems confusing, look at the consumers.
 *
 * This magic serves two purposes:
 * (1) It completely hides the transactions' internals from the module
 *     consumers.
 * (2) It keeps each transaction implementation to what is about, bypassing
 *     all this bureaucracy while still validating input appropriately.
 */
function DefineTransaction(requiredProps = [], optionalProps = []) {
  for (let prop of [...requiredProps, ...optionalProps]) {
    if (!DefineTransaction.inputProps.has(prop)) {
      throw new Error("Property '" + prop + "' is not defined");
    }
  }

  let ctor = function (input) {
    // We want to support both syntaxes:
    // let t = new PlacesTransactions.NewBookmark(),
    // let t = PlacesTransactions.NewBookmark()
    if (this == PlacesTransactions) {
      return new ctor(input);
    }

    if (requiredProps.length || optionalProps.length) {
      // Bind the input properties to the arguments of execute.
      input = DefineTransaction.verifyInput(
        input,
        requiredProps,
        optionalProps
      );
      this.execute = this.execute.bind(this, input);
    }
    return lazy.TransactionsHistory.proxifyTransaction(this);
  };
  return ctor;
}

function simpleValidateFunc(checkFn) {
  return v => {
    if (!checkFn(v)) {
      throw new Error("Invalid value");
    }
    return v;
  };
}

DefineTransaction.strValidate = simpleValidateFunc(v => typeof v == "string");
DefineTransaction.strOrNullValidate = simpleValidateFunc(
  v => typeof v == "string" || v === null
);
DefineTransaction.indexValidate = simpleValidateFunc(
  v => Number.isInteger(v) && v >= PlacesUtils.bookmarks.DEFAULT_INDEX
);
DefineTransaction.guidValidate = simpleValidateFunc(v =>
  /^[a-zA-Z0-9\-_]{12}$/.test(v)
);

function isPrimitive(v) {
  return v === null || (typeof v != "object" && typeof v != "function");
}

function checkProperty(obj, prop, required, checkFn) {
  if (prop in obj) {
    return checkFn(obj[prop]);
  }

  return !required;
}

DefineTransaction.childObjectValidate = function (obj) {
  if (
    obj &&
    checkProperty(obj, "title", false, v => typeof v == "string") &&
    !("type" in obj && obj.type != PlacesUtils.bookmarks.TYPE_BOOKMARK)
  ) {
    obj.url = DefineTransaction.urlValidate(obj.url);
    let validKeys = ["title", "url"];
    if (Object.keys(obj).every(k => validKeys.includes(k))) {
      return obj;
    }
  }
  throw new Error("Invalid child object");
};

DefineTransaction.urlValidate = function (url) {
  if (url instanceof Ci.nsIURI) {
    return URL.fromURI(url);
  }
  return new URL(url);
};

DefineTransaction.inputProps = new Map();
DefineTransaction.defineInputProps = function (
  names,
  validateFn,
  defaultValue
) {
  for (let name of names) {
    this.inputProps.set(name, {
      validateValue(value) {
        if (value === undefined) {
          return defaultValue;
        }
        try {
          return validateFn(value);
        } catch (ex) {
          throw new Error(`Invalid value for input property ${name}: ${ex}`);
        }
      },

      validateInput(input, required) {
        if (required && !(name in input)) {
          throw new Error(`Required input property is missing: ${name}`);
        }
        return this.validateValue(input[name]);
      },

      isArrayProperty: false,
    });
  }
};

DefineTransaction.defineArrayInputProp = function (name, basePropertyName) {
  let baseProp = this.inputProps.get(basePropertyName);
  if (!baseProp) {
    throw new Error(`Unknown input property: ${basePropertyName}`);
  }

  this.inputProps.set(name, {
    validateValue(aValue) {
      if (aValue == undefined) {
        return [];
      }

      if (!Array.isArray(aValue)) {
        throw new Error(`${name} input property value must be an array`);
      }

      // We must create a new array in the local scope to avoid a memory leak due
      // to the array global object. We can't use Cu.cloneInto as that doesn't
      // handle the URIs. Slice & map also aren't good enough, so we start off
      // with a clean array and insert what we need into it.
      let newArray = [];
      for (let item of aValue) {
        newArray.push(baseProp.validateValue(item));
      }
      return newArray;
    },

    // We allow setting either the array property itself (e.g. urls), or a
    // single element of it (url, in that example), that is then transformed
    // into a single-element array.
    validateInput(input, required) {
      if (name in input) {
        // It's not allowed to set both though.
        if (basePropertyName in input) {
          throw new Error(`It is not allowed to set both ${name} and
                          ${basePropertyName} as  input properties`);
        }
        let array = this.validateValue(input[name]);
        if (required && !array.length) {
          throw new Error(`Empty array passed for required input property:
                           ${name}`);
        }
        return array;
      }
      // If the property is required and it's not set as is, check if the base
      // property is set.
      if (required && !(basePropertyName in input)) {
        throw new Error(`Required input property is missing: ${name}`);
      }

      if (basePropertyName in input) {
        return [baseProp.validateValue(input[basePropertyName])];
      }

      return [];
    },

    isArrayProperty: true,
  });
};

DefineTransaction.validatePropertyValue = function (prop, input, required) {
  return this.inputProps.get(prop).validateInput(input, required);
};

DefineTransaction.getInputObjectForSingleValue = function (
  input,
  requiredProps,
  optionalProps
) {
  // The following input forms may be deduced from a single value:
  // * a single required property with or without optional properties (the given
  //   value is set to the required property).
  // * a single optional property with no required properties.
  if (
    requiredProps.length > 1 ||
    (!requiredProps.length && optionalProps.length > 1)
  ) {
    throw new Error("Transaction input isn't an object");
  }

  let propName =
    requiredProps.length == 1 ? requiredProps[0] : optionalProps[0];
  let propValue =
    this.inputProps.get(propName).isArrayProperty && !Array.isArray(input)
      ? [input]
      : input;
  return { [propName]: propValue };
};

DefineTransaction.verifyInput = function (
  input,
  requiredProps = [],
  optionalProps = []
) {
  if (!requiredProps.length && !optionalProps.length) {
    return {};
  }

  // If there's just a single required/optional property, we allow passing it
  // as is, so, for example, one could do PlacesTransactions.Remove(myGuid)
  // rather than PlacesTransactions.Remove({ guid: myGuid}).
  // This shortcut isn't supported for "complex" properties, like objects (note
  // there is no use case for this at the moment anyway).
  let isSinglePropertyInput =
    isPrimitive(input) ||
    Array.isArray(input) ||
    input instanceof Ci.nsISupports;
  if (isSinglePropertyInput) {
    input = this.getInputObjectForSingleValue(
      input,
      requiredProps,
      optionalProps
    );
  }

  let fixedInput = {};
  for (let prop of requiredProps) {
    fixedInput[prop] = this.validatePropertyValue(prop, input, true);
  }
  for (let prop of optionalProps) {
    fixedInput[prop] = this.validatePropertyValue(prop, input, false);
  }

  return fixedInput;
};

// Update the documentation at the top of this module if you add or
// remove properties.
DefineTransaction.defineInputProps(
  ["url"],
  DefineTransaction.urlValidate,
  null
);
DefineTransaction.defineInputProps(
  ["guid", "parentGuid", "newParentGuid"],
  DefineTransaction.guidValidate
);
DefineTransaction.defineInputProps(
  ["title", "postData"],
  DefineTransaction.strOrNullValidate,
  null
);
DefineTransaction.defineInputProps(
  ["keyword", "oldKeyword", "oldTag", "tag"],
  DefineTransaction.strValidate,
  ""
);
DefineTransaction.defineInputProps(
  ["index", "newIndex"],
  DefineTransaction.indexValidate,
  PlacesUtils.bookmarks.DEFAULT_INDEX
);
DefineTransaction.defineInputProps(
  ["child"],
  DefineTransaction.childObjectValidate
);
DefineTransaction.defineArrayInputProp("guids", "guid");
DefineTransaction.defineArrayInputProp("urls", "url");
DefineTransaction.defineArrayInputProp("tags", "tag");
DefineTransaction.defineArrayInputProp("children", "child");

/**
 * Creates items (all types) from a bookmarks tree representation, as defined
 * in PlacesUtils.promiseBookmarksTree.
 *
 * @param tree
 *        the bookmarks tree object.  You may pass either a bookmarks tree
 *        returned by promiseBookmarksTree, or a manually defined one.
 * @param [optional] restoring (default: false)
 *        Whether or not the items are restored.  Only in restore mode, are
 *        the guid, dateAdded and lastModified properties honored.
 * @note the id, root and charset properties of items in aBookmarksTree are
 *       always ignored.  The index property is ignored for all items but the
 *       root one.
 * @return {Promise}
 * @resolves to the guid of the new item.
 */
// TODO: Replace most of this with insertTree.
function createItemsFromBookmarksTree(tree, restoring = false) {
  async function createItem(
    item,
    parentGuid,
    index = PlacesUtils.bookmarks.DEFAULT_INDEX
  ) {
    let guid;
    let info = { parentGuid, index };
    if (restoring) {
      info.guid = item.guid;
      info.dateAdded = PlacesUtils.toDate(item.dateAdded);
      info.lastModified = PlacesUtils.toDate(item.lastModified);
    }
    let shouldResetLastModified = false;
    switch (item.type) {
      case PlacesUtils.TYPE_X_MOZ_PLACE: {
        info.url = item.uri;
        if (typeof item.title == "string") {
          info.title = item.title;
        }

        guid = (await PlacesUtils.bookmarks.insert(info)).guid;

        if ("keyword" in item) {
          let { uri: url, keyword, postData } = item;
          await PlacesUtils.keywords.insert({ url, keyword, postData });
        }
        if ("tags" in item) {
          PlacesUtils.tagging.tagURI(
            Services.io.newURI(item.uri),
            item.tags.split(",")
          );
        }
        break;
      }
      case PlacesUtils.TYPE_X_MOZ_PLACE_CONTAINER: {
        info.type = PlacesUtils.bookmarks.TYPE_FOLDER;
        if (typeof item.title == "string") {
          info.title = item.title;
        }
        guid = (await PlacesUtils.bookmarks.insert(info)).guid;
        if ("children" in item) {
          for (let child of item.children) {
            await createItem(child, guid);
          }
        }
        if (restoring) {
          shouldResetLastModified = true;
        }
        break;
      }
      case PlacesUtils.TYPE_X_MOZ_PLACE_SEPARATOR: {
        info.type = PlacesUtils.bookmarks.TYPE_SEPARATOR;
        guid = (await PlacesUtils.bookmarks.insert(info)).guid;
        break;
      }
    }

    if (shouldResetLastModified) {
      let lastModified = PlacesUtils.toDate(item.lastModified);
      await PlacesUtils.bookmarks.update({ guid, lastModified });
    }

    return guid;
  }
  return createItem(tree, tree.parentGuid, tree.index);
}

/** ***************************************************************************
 * The Standard Places Transactions.
 *
 * See the documentation at the top of this file. The valid values for input
 * are also documented there.
 *****************************************************************************/

var PT = PlacesTransactions;

/**
 * Transaction for creating a bookmark.
 *
 * Required Input Properties: url, parentGuid.
 * Optional Input Properties: index, title, keyword, tags.
 *
 * When this transaction is executed, it's resolved to the new bookmark's GUID.
 */
PT.NewBookmark = DefineTransaction(
  ["parentGuid", "url"],
  ["index", "title", "tags"]
);
PT.NewBookmark.prototype = Object.seal({
  async execute({ parentGuid, url, index, title, tags }) {
    let info = { parentGuid, index, url, title };
    // Filter tags to exclude already existing ones.
    if (tags.length) {
      let currentTags = PlacesUtils.tagging.getTagsForURI(url.URI);
      tags = tags.filter(t => !currentTags.includes(t));
    }

    async function createItem() {
      info = await PlacesUtils.bookmarks.insert(info);
      if (tags.length) {
        PlacesUtils.tagging.tagURI(url.URI, tags);
      }
    }

    await createItem();

    this.undo = async function () {
      // Pick up the removed info so we have the accurate last-modified value.
      await PlacesUtils.bookmarks.remove(info);
      if (tags.length) {
        PlacesUtils.tagging.untagURI(url.URI, tags);
      }
    };
    this.redo = async function () {
      await createItem();
    };
    return info.guid;
  },
  toString() {
    return "NewBookmark";
  },
});

/**
 * Transaction for creating a folder.
 *
 * Required Input Properties: title, parentGuid.
 * Optional Input Properties: index, children
 *
 * When this transaction is executed, it's resolved to the new folder's GUID.
 */
PT.NewFolder = DefineTransaction(
  ["parentGuid", "title"],
  ["index", "children"]
);
PT.NewFolder.prototype = Object.seal({
  async execute({ parentGuid, title, index, children }) {
    let folderGuid;
    let info = {
      children: [
        {
          // Ensure to specify a guid to be restored on redo.
          guid: PlacesUtils.history.makeGuid(),
          title,
          type: PlacesUtils.bookmarks.TYPE_FOLDER,
        },
      ],
      // insertTree uses guid as the parent for where it is being inserted
      // into.
      guid: parentGuid,
    };

    if (children && children.length) {
      // Ensure to specify a guid for each child to be restored on redo.
      info.children[0].children = children.map(c => {
        c.guid = PlacesUtils.history.makeGuid();
        return c;
      });
    }

    async function createItem() {
      // Note, insertTree returns an array, rather than the folder/child structure.
      // For simplicity, we only get the new folder id here. This means that
      // an undo then redo won't retain exactly the same information for all
      // the child bookmarks, but we believe that isn't important at the moment.
      let bmInfo = await PlacesUtils.bookmarks.insertTree(info);
      // insertTree returns an array, but we only need to deal with the folder guid.
      folderGuid = bmInfo[0].guid;

      // Bug 1388097: insertTree doesn't handle inserting at a specific index for the folder,
      // therefore we update the bookmark manually afterwards.
      if (index != PlacesUtils.bookmarks.DEFAULT_INDEX) {
        bmInfo[0].index = index;
        bmInfo = await PlacesUtils.bookmarks.update(bmInfo[0]);
      }
    }
    await createItem();

    this.undo = async function () {
      await PlacesUtils.bookmarks.remove(folderGuid);
    };
    this.redo = async function () {
      await createItem();
    };
    return folderGuid;
  },
  toString() {
    return "NewFolder";
  },
});

/**
 * Transaction for creating a separator.
 *
 * Required Input Properties: parentGuid.
 * Optional Input Properties: index.
 *
 * When this transaction is executed, it's resolved to the new separator's
 * GUID.
 */
PT.NewSeparator = DefineTransaction(["parentGuid"], ["index"]);
PT.NewSeparator.prototype = Object.seal({
  async execute(info) {
    info.type = PlacesUtils.bookmarks.TYPE_SEPARATOR;
    info = await PlacesUtils.bookmarks.insert(info);
    this.undo = PlacesUtils.bookmarks.remove.bind(PlacesUtils.bookmarks, info);
    this.redo = PlacesUtils.bookmarks.insert.bind(PlacesUtils.bookmarks, info);
    return info.guid;
  },
  toString() {
    return "NewSeparator";
  },
});

/**
 * Transaction for moving an item.
 *
 * Required Input Properties: guid, newParentGuid.
 * Optional Input Properties  newIndex.
 */
PT.Move = DefineTransaction(["guids", "newParentGuid"], ["newIndex"]);
PT.Move.prototype = Object.seal({
  async execute({ guids, newParentGuid, newIndex }) {
    let originalInfos = [];
    let index = newIndex;

    for (let guid of guids) {
      // We need to save the original data for undo.
      let originalInfo = await PlacesUtils.bookmarks.fetch(guid);
      if (!originalInfo) {
        throw new Error("Cannot move a non-existent item");
      }

      originalInfos.push(originalInfo);
    }

    await PlacesUtils.bookmarks.moveToFolder(guids, newParentGuid, index);

    this.undo = async function () {
      // Undo has the potential for moving multiple bookmarks to multiple different
      // folders and positions, which is very complicated to manage. Therefore we do
      // individual moves one at a time and hopefully everything is put back approximately
      // where it should be.
      for (let info of originalInfos) {
        await PlacesUtils.bookmarks.update(info);
      }
    };
    this.redo = PlacesUtils.bookmarks.moveToFolder.bind(
      PlacesUtils.bookmarks,
      guids,
      newParentGuid,
      index
    );
    return guids;
  },
  toString() {
    return "Move";
  },
});

/**
 * Transaction for setting the title for an item.
 *
 * Required Input Properties: guid, title.
 */
PT.EditTitle = DefineTransaction(["guid", "title"]);
PT.EditTitle.prototype = Object.seal({
  async execute({ guid, title }) {
    let originalInfo = await PlacesUtils.bookmarks.fetch(guid);
    if (!originalInfo) {
      throw new Error("cannot update a non-existent item");
    }

    let updateInfo = { guid, title };
    updateInfo = await PlacesUtils.bookmarks.update(updateInfo);

    this.undo = PlacesUtils.bookmarks.update.bind(
      PlacesUtils.bookmarks,
      originalInfo
    );
    this.redo = PlacesUtils.bookmarks.update.bind(
      PlacesUtils.bookmarks,
      updateInfo
    );
  },
  toString() {
    return "EditTitle";
  },
});

/**
 * Transaction for setting the URI for an item.
 *
 * Required Input Properties: guid, url.
 */
PT.EditUrl = DefineTransaction(["guid", "url"]);
PT.EditUrl.prototype = Object.seal({
  async execute({ guid, url }) {
    let originalInfo = await PlacesUtils.bookmarks.fetch(guid);
    if (!originalInfo) {
      throw new Error("cannot update a non-existent item");
    }
    if (originalInfo.type != PlacesUtils.bookmarks.TYPE_BOOKMARK) {
      throw new Error("Cannot edit url for non-bookmark items");
    }

    let uri = url.URI;
    let originalURI = originalInfo.url.URI;
    let originalTags = PlacesUtils.tagging.getTagsForURI(originalURI);
    let updatedInfo = { guid, url };
    let newURIAdditionalTags = null;

    async function updateItem() {
      updatedInfo = await PlacesUtils.bookmarks.update(updatedInfo);
      // Move tags from the original URI to the new URI.
      if (originalTags.length) {
        // Untag the original URI only if this was the only bookmark.
        if (!(await PlacesUtils.bookmarks.fetch({ url: originalInfo.url }))) {
          PlacesUtils.tagging.untagURI(originalURI, originalTags);
        }
        let currentNewURITags = PlacesUtils.tagging.getTagsForURI(uri);
        newURIAdditionalTags = originalTags.filter(
          t => !currentNewURITags.includes(t)
        );
        if (newURIAdditionalTags && newURIAdditionalTags.length) {
          PlacesUtils.tagging.tagURI(uri, newURIAdditionalTags);
        }
      }
    }
    await updateItem();

    this.undo = async function () {
      await PlacesUtils.bookmarks.update(originalInfo);
      // Move tags from new URI to original URI.
      if (originalTags.length) {
        // Only untag the new URI if this is the only bookmark.
        if (
          newURIAdditionalTags &&
          !!newURIAdditionalTags.length &&
          !(await PlacesUtils.bookmarks.fetch({ url }))
        ) {
          PlacesUtils.tagging.untagURI(uri, newURIAdditionalTags);
        }
        PlacesUtils.tagging.tagURI(originalURI, originalTags);
      }
    };

    this.redo = async function () {
      updatedInfo = await updateItem();
    };
  },
  toString() {
    return "EditUrl";
  },
});

/**
 * Transaction for setting the keyword for a bookmark.
 *
 * Required Input Properties: guid, keyword.
 * Optional Input Properties: postData, oldKeyword.
 */
PT.EditKeyword = DefineTransaction(
  ["guid", "keyword"],
  ["postData", "oldKeyword"]
);
PT.EditKeyword.prototype = Object.seal({
  async execute({ guid, keyword, postData, oldKeyword }) {
    let url;
    let oldKeywordEntry;
    if (oldKeyword) {
      oldKeywordEntry = await PlacesUtils.keywords.fetch(oldKeyword);
      url = oldKeywordEntry.url;
      await PlacesUtils.keywords.remove(oldKeyword);
    }

    if (keyword) {
      if (!url) {
        url = (await PlacesUtils.bookmarks.fetch(guid)).url;
      }
      await PlacesUtils.keywords.insert({
        url,
        keyword,
        postData: postData || (oldKeywordEntry ? oldKeywordEntry.postData : ""),
      });
    }

    this.undo = async function () {
      if (keyword) {
        await PlacesUtils.keywords.remove(keyword);
      }
      if (oldKeywordEntry) {
        await PlacesUtils.keywords.insert(oldKeywordEntry);
      }
    };
  },
  toString() {
    return "EditKeyword";
  },
});

/**
 * Transaction for sorting a folder by name.
 *
 * Required Input Properties: guid.
 */
PT.SortByName = DefineTransaction(["guid"]);
PT.SortByName.prototype = {
  async execute({ guid }) {
    let sortingMethod = (node_a, node_b) => {
      if (
        PlacesUtils.nodeIsContainer(node_a) &&
        !PlacesUtils.nodeIsContainer(node_b)
      ) {
        return -1;
      }
      if (
        !PlacesUtils.nodeIsContainer(node_a) &&
        PlacesUtils.nodeIsContainer(node_b)
      ) {
        return 1;
      }
      return node_a.title.localeCompare(node_b.title);
    };
    let oldOrderGuids = [];
    let newOrderGuids = [];
    let preSepNodes = [];

    // This is not great, since it does main-thread IO.
    // PromiseBookmarksTree can't be used, since it' won't stop at the first level'.
    let root = PlacesUtils.getFolderContents(guid, false, false).root;
    for (let i = 0; i < root.childCount; ++i) {
      let node = root.getChild(i);
      oldOrderGuids.push(node.bookmarkGuid);
      if (PlacesUtils.nodeIsSeparator(node)) {
        if (preSepNodes.length) {
          preSepNodes.sort(sortingMethod);
          newOrderGuids.push(...preSepNodes.map(n => n.bookmarkGuid));
          preSepNodes = [];
        }
        newOrderGuids.push(node.bookmarkGuid);
      } else {
        preSepNodes.push(node);
      }
    }
    root.containerOpen = false;
    if (preSepNodes.length) {
      preSepNodes.sort(sortingMethod);
      newOrderGuids.push(...preSepNodes.map(n => n.bookmarkGuid));
    }
    await PlacesUtils.bookmarks.reorder(guid, newOrderGuids);

    this.undo = async function () {
      await PlacesUtils.bookmarks.reorder(guid, oldOrderGuids);
    };
    this.redo = async function () {
      await PlacesUtils.bookmarks.reorder(guid, newOrderGuids);
    };
  },
  toString() {
    return "SortByName";
  },
};

/**
 * Transaction for removing an item (any type).
 *
 * Required Input Properties: guids.
 */
PT.Remove = DefineTransaction(["guids"]);
PT.Remove.prototype = {
  async execute({ guids }) {
    let removedItems = [];

    for (let guid of guids) {
      try {
        // Although we don't strictly need to get this information for the remove,
        // we do need it for the possibility of undo().
        removedItems.push(await PlacesUtils.promiseBookmarksTree(guid));
      } catch (ex) {
        if (!ex.becauseInvalidURL) {
          throw new Error(`Failed to get info for the guid: ${guid}: ${ex}`);
        }
        removedItems.push({ guid });
      }
    }

    let removeThem = async function () {
      if (removedItems.length) {
        // We have to pass just the guids as although remove() accepts full
        // info items, promiseBookmarksTree returns dateAdded and lastModified
        // as PRTime rather than date types.
        await PlacesUtils.bookmarks.remove(
          removedItems.map(info => ({ guid: info.guid }))
        );
      }
    };
    await removeThem();

    this.undo = async function () {
      for (let info of removedItems) {
        try {
          await createItemsFromBookmarksTree(info, true);
        } catch (ex) {
          console.error(`Unable to undo removal of ${info.guid}`);
        }
      }
    };
    this.redo = removeThem;
  },
  toString() {
    return "Remove";
  },
};

/**
 * Transaction for tagging urls.
 *
 * Required Input Properties: urls, tags.
 */
PT.Tag = DefineTransaction(["urls", "tags"]);
PT.Tag.prototype = {
  async execute({ urls, tags }) {
    let onUndo = [],
      onRedo = [];
    for (let url of urls) {
      if (!(await PlacesUtils.bookmarks.fetch({ url }))) {
        // Tagging is only allowed for bookmarked URIs (but see 424160).
        let createTxn = lazy.TransactionsHistory.getRawTransaction(
          PT.NewBookmark({
            url,
            tags,
            parentGuid: PlacesUtils.bookmarks.unfiledGuid,
          })
        );
        await createTxn.execute();
        onUndo.unshift(createTxn.undo.bind(createTxn));
        onRedo.push(createTxn.redo.bind(createTxn));
      } else {
        let uri = url.URI;
        let currentTags = PlacesUtils.tagging.getTagsForURI(uri);
        let newTags = tags.filter(t => !currentTags.includes(t));
        if (newTags.length) {
          PlacesUtils.tagging.tagURI(uri, newTags);
          onUndo.unshift(() => {
            PlacesUtils.tagging.untagURI(uri, newTags);
          });
          onRedo.push(() => {
            PlacesUtils.tagging.tagURI(uri, newTags);
          });
        }
      }
    }
    this.undo = async function () {
      for (let f of onUndo) {
        await f();
      }
    };
    this.redo = async function () {
      for (let f of onRedo) {
        await f();
      }
    };
  },
  toString() {
    return "Tag";
  },
};

/**
 * Transaction for removing tags from a URI.
 *
 * Required Input Properties: urls.
 * Optional Input Properties: tags.
 *
 * If |tags| is not set, all tags set for |url| are removed.
 */
PT.Untag = DefineTransaction(["urls"], ["tags"]);
PT.Untag.prototype = {
  execute({ urls, tags }) {
    let onUndo = [],
      onRedo = [];
    for (let url of urls) {
      let uri = url.URI;
      let tagsToRemove;
      let tagsSet = PlacesUtils.tagging.getTagsForURI(uri);
      if (tags.length) {
        tagsToRemove = tags.filter(t => tagsSet.includes(t));
      } else {
        tagsToRemove = tagsSet;
      }
      if (tagsToRemove.length) {
        PlacesUtils.tagging.untagURI(uri, tagsToRemove);
      }
      onUndo.unshift(() => {
        if (tagsToRemove.length) {
          PlacesUtils.tagging.tagURI(uri, tagsToRemove);
        }
      });
      onRedo.push(() => {
        if (tagsToRemove.length) {
          PlacesUtils.tagging.untagURI(uri, tagsToRemove);
        }
      });
    }
    this.undo = async function () {
      for (let f of onUndo) {
        await f();
      }
    };
    this.redo = async function () {
      for (let f of onRedo) {
        await f();
      }
    };
  },
  toString() {
    return "Untag";
  },
};

/**
 * Transaction for renaming a tag.
 *
 * Required Input Properties: oldTag, tag.
 */
PT.RenameTag = DefineTransaction(["oldTag", "tag"]);
PT.RenameTag.prototype = {
  async execute({ oldTag, tag }) {
    // For now this is implemented by untagging and tagging all the bookmarks.
    // We should create a specialized bookmarking API to just rename the tag.
    let onUndo = [],
      onRedo = [];
    let urls = new Set();
    await PlacesUtils.bookmarks.fetch({ tags: [oldTag] }, b => urls.add(b.url));
    if (urls.size > 0) {
      urls = Array.from(urls);
      let tagTxn = lazy.TransactionsHistory.getRawTransaction(
        PT.Tag({ urls, tags: [tag] })
      );
      await tagTxn.execute();
      onUndo.unshift(tagTxn.undo.bind(tagTxn));
      onRedo.push(tagTxn.redo.bind(tagTxn));
      let untagTxn = lazy.TransactionsHistory.getRawTransaction(
        PT.Untag({ urls, tags: [oldTag] })
      );
      await untagTxn.execute();
      onUndo.unshift(untagTxn.undo.bind(untagTxn));
      onRedo.push(untagTxn.redo.bind(untagTxn));

      // Update all the place: queries that refer to this tag.
      let db = await PlacesUtils.promiseDBConnection();
      let rows = await db.executeCached(
        `
        SELECT h.url, b.guid, b.title
        FROM moz_places h
        JOIN moz_bookmarks b ON b.fk = h.id
        WHERE url_hash BETWEEN hash("place", "prefix_lo")
                           AND hash("place", "prefix_hi")
          AND url LIKE :tagQuery
      `,
        { tagQuery: "%tag=%" }
      );
      for (let row of rows) {
        let url = row.getResultByName("url");
        try {
          url = new URL(url);
          let urlParams = new URLSearchParams(url.pathname);
          let tags = urlParams.getAll("tag");
          if (!tags.includes(oldTag)) {
            continue;
          }
          if (tags.length > 1) {
            // URLSearchParams cannot set more than 1 same-named param.
            urlParams.delete("tag");
            urlParams.set("tag", tag);
            url = new URL(
              url.protocol +
                urlParams +
                "&tag=" +
                tags.filter(t => t != oldTag).join("&tag=")
            );
          } else {
            urlParams.set("tag", tag);
            url = new URL(url.protocol + urlParams);
          }
        } catch (ex) {
          console.error(
            "Invalid bookmark url: " + row.getResultByName("url") + ": " + ex
          );
          continue;
        }
        let guid = row.getResultByName("guid");
        let title = row.getResultByName("title");

        let editUrlTxn = lazy.TransactionsHistory.getRawTransaction(
          PT.EditUrl({ guid, url })
        );
        await editUrlTxn.execute();
        onUndo.unshift(editUrlTxn.undo.bind(editUrlTxn));
        onRedo.push(editUrlTxn.redo.bind(editUrlTxn));
        if (title == oldTag) {
          let editTitleTxn = lazy.TransactionsHistory.getRawTransaction(
            PT.EditTitle({ guid, title: tag })
          );
          await editTitleTxn.execute();
          onUndo.unshift(editTitleTxn.undo.bind(editTitleTxn));
          onRedo.push(editTitleTxn.redo.bind(editTitleTxn));
        }
      }
    }
    this.undo = async function () {
      for (let f of onUndo) {
        await f();
      }
    };
    this.redo = async function () {
      for (let f of onRedo) {
        await f();
      }
    };
  },
  toString() {
    return "RenameTag";
  },
};

/**
 * Transaction for copying an item.
 *
 * Required Input Properties: guid, newParentGuid
 * Optional Input Properties: newIndex.
 */
PT.Copy = DefineTransaction(["guid", "newParentGuid"], ["newIndex"]);
PT.Copy.prototype = {
  async execute({ guid, newParentGuid, newIndex }) {
    let creationInfo = null;
    try {
      creationInfo = await PlacesUtils.promiseBookmarksTree(guid);
    } catch (ex) {
      throw new Error(
        "Failed to get info for the specified item (guid: " +
          guid +
          "). Ex: " +
          ex
      );
    }
    creationInfo.parentGuid = newParentGuid;
    creationInfo.index = newIndex;

    let newItemGuid = await createItemsFromBookmarksTree(creationInfo, false);
    let newItemInfo = null;
    this.undo = async function () {
      if (!newItemInfo) {
        newItemInfo = await PlacesUtils.promiseBookmarksTree(newItemGuid);
      }
      await PlacesUtils.bookmarks.remove(newItemGuid);
    };
    this.redo = async function () {
      await createItemsFromBookmarksTree(newItemInfo, true);
    };

    return newItemGuid;
  },
  toString() {
    return "Copy";
  },
};