summaryrefslogtreecommitdiff
path: root/includes/api/ApiPageSet.php
blob: b05cb2b67bdfaf5fdb9aa459ae09588a9dd85476 (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
<?php
/**
 *
 *
 * Created on Sep 24, 2006
 *
 * Copyright © 2006, 2013 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

/**
 * This class contains a list of pages that the client has requested.
 * Initially, when the client passes in titles=, pageids=, or revisions=
 * parameter, an instance of the ApiPageSet class will normalize titles,
 * determine if the pages/revisions exist, and prefetch any additional page
 * data requested.
 *
 * When a generator is used, the result of the generator will become the input
 * for the second instance of this class, and all subsequent actions will use
 * the second instance for all their work.
 *
 * @ingroup API
 * @since 1.21 derives from ApiBase instead of ApiQueryBase
 */
class ApiPageSet extends ApiBase {

	/**
	 * Constructor flag: The new instance of ApiPageSet will ignore the 'generator=' parameter
	 * @since 1.21
	 */
	const DISABLE_GENERATORS = 1;

	private $mDbSource;
	private $mParams;
	private $mResolveRedirects;
	private $mConvertTitles;
	private $mAllowGenerator;

	private $mAllPages = array(); // [ns][dbkey] => page_id or negative when missing
	private $mTitles = array();
	private $mGoodTitles = array();
	private $mMissingTitles = array();
	private $mInvalidTitles = array();
	private $mMissingPageIDs = array();
	private $mRedirectTitles = array();
	private $mSpecialTitles = array();
	private $mNormalizedTitles = array();
	private $mInterwikiTitles = array();
	private $mPendingRedirectIDs = array();
	private $mConvertedTitles = array();
	private $mGoodRevIDs = array();
	private $mMissingRevIDs = array();
	private $mFakePageId = -1;
	private $mCacheMode = 'public';
	private $mRequestedPageFields = array();
	/**
	 * @var int
	 */
	private $mDefaultNamespace = NS_MAIN;

	/**
	 * Constructor
	 * @param $dbSource ApiBase Module implementing getDB().
	 *        Allows PageSet to reuse existing db connection from the shared state like ApiQuery.
	 * @param int $flags Zero or more flags like DISABLE_GENERATORS
	 * @param int $defaultNamespace the namespace to use if none is specified by a prefix.
	 * @since 1.21 accepts $flags instead of two boolean values
	 */
	public function __construct( ApiBase $dbSource, $flags = 0, $defaultNamespace = NS_MAIN ) {
		parent::__construct( $dbSource->getMain(), $dbSource->getModuleName() );
		$this->mDbSource = $dbSource;
		$this->mAllowGenerator = ( $flags & ApiPageSet::DISABLE_GENERATORS ) == 0;
		$this->mDefaultNamespace = $defaultNamespace;

		$this->profileIn();
		$this->mParams = $this->extractRequestParams();
		$this->mResolveRedirects = $this->mParams['redirects'];
		$this->mConvertTitles = $this->mParams['converttitles'];
		$this->profileOut();
	}

	/**
	 * In case execute() is not called, call this method to mark all relevant parameters as used
	 * This prevents unused parameters from being reported as warnings
	 */
	public function executeDryRun() {
		$this->executeInternal( true );
	}

	/**
	 * Populate the PageSet from the request parameters.
	 */
	public function execute() {
		$this->executeInternal( false );
	}

	/**
	 * Populate the PageSet from the request parameters.
	 * @param bool $isDryRun If true, instantiates generator, but only to mark relevant parameters as used
	 */
	private function executeInternal( $isDryRun ) {
		$this->profileIn();

		$generatorName = $this->mAllowGenerator ? $this->mParams['generator'] : null;
		if ( isset( $generatorName ) ) {
			$dbSource = $this->mDbSource;
			$isQuery = $dbSource instanceof ApiQuery;
			if ( !$isQuery ) {
				// If the parent container of this pageset is not ApiQuery, we must create it to run generator
				$dbSource = $this->getMain()->getModuleManager()->getModule( 'query' );
				// Enable profiling for query module because it will be used for db sql profiling
				$dbSource->profileIn();
			}
			$generator = $dbSource->getModuleManager()->getModule( $generatorName, null, true );
			if ( $generator === null ) {
				$this->dieUsage( 'Unknown generator=' . $generatorName, 'badgenerator' );
			}
			if ( !$generator instanceof ApiQueryGeneratorBase ) {
				$this->dieUsage( "Module $generatorName cannot be used as a generator", 'badgenerator' );
			}
			// Create a temporary pageset to store generator's output,
			// add any additional fields generator may need, and execute pageset to populate titles/pageids
			$tmpPageSet = new ApiPageSet( $dbSource, ApiPageSet::DISABLE_GENERATORS );
			$generator->setGeneratorMode( $tmpPageSet );
			$this->mCacheMode = $generator->getCacheMode( $generator->extractRequestParams() );

			if ( !$isDryRun ) {
				$generator->requestExtraData( $tmpPageSet );
			}
			$tmpPageSet->executeInternal( $isDryRun );

			// populate this pageset with the generator output
			$this->profileOut();
			$generator->profileIn();

			if ( !$isDryRun ) {
				$generator->executeGenerator( $this );
				wfRunHooks( 'APIQueryGeneratorAfterExecute', array( &$generator, &$this ) );
			} else {
				// Prevent warnings from being reported on these parameters
				$main = $this->getMain();
				foreach ( $generator->extractRequestParams() as $paramName => $param ) {
					$main->getVal( $generator->encodeParamName( $paramName ) );
				}
			}
			$generator->profileOut();
			$this->profileIn();

			if ( !$isDryRun ) {
				$this->resolvePendingRedirects();
			}

			if ( !$isQuery ) {
				// If this pageset is not part of the query, we called profileIn() above
				$dbSource->profileOut();
			}
		} else {
			// Only one of the titles/pageids/revids is allowed at the same time
			$dataSource = null;
			if ( isset( $this->mParams['titles'] ) ) {
				$dataSource = 'titles';
			}
			if ( isset( $this->mParams['pageids'] ) ) {
				if ( isset( $dataSource ) ) {
					$this->dieUsage( "Cannot use 'pageids' at the same time as '$dataSource'", 'multisource' );
				}
				$dataSource = 'pageids';
			}
			if ( isset( $this->mParams['revids'] ) ) {
				if ( isset( $dataSource ) ) {
					$this->dieUsage( "Cannot use 'revids' at the same time as '$dataSource'", 'multisource' );
				}
				$dataSource = 'revids';
			}

			if ( !$isDryRun ) {
				// Populate page information with the original user input
				switch ( $dataSource ) {
					case 'titles':
						$this->initFromTitles( $this->mParams['titles'] );
						break;
					case 'pageids':
						$this->initFromPageIds( $this->mParams['pageids'] );
						break;
					case 'revids':
						if ( $this->mResolveRedirects ) {
							$this->setWarning( 'Redirect resolution cannot be used together with the revids= parameter. ' .
								'Any redirects the revids= point to have not been resolved.' );
						}
						$this->mResolveRedirects = false;
						$this->initFromRevIDs( $this->mParams['revids'] );
						break;
					default:
						// Do nothing - some queries do not need any of the data sources.
						break;
				}
			}
		}
		$this->profileOut();
	}

	/**
	 * Check whether this PageSet is resolving redirects
	 * @return bool
	 */
	public function isResolvingRedirects() {
		return $this->mResolveRedirects;
	}

	/**
	 * Return the parameter name that is the source of data for this PageSet
	 *
	 * If multiple source parameters are specified (e.g. titles and pageids),
	 * one will be named arbitrarily.
	 *
	 * @return string|null
	 */
	public function getDataSource() {
		if ( $this->mAllowGenerator && isset( $this->mParams['generator'] ) ) {
			return 'generator';
		}
		if ( isset( $this->mParams['titles'] ) ) {
			return 'titles';
		}
		if ( isset( $this->mParams['pageids'] ) ) {
			return 'pageids';
		}
		if ( isset( $this->mParams['revids'] ) ) {
			return 'revids';
		}
		return null;
	}

	/**
	 * Request an additional field from the page table.
	 * Must be called before execute()
	 * @param string $fieldName Field name
	 */
	public function requestField( $fieldName ) {
		$this->mRequestedPageFields[$fieldName] = null;
	}

	/**
	 * Get the value of a custom field previously requested through
	 * requestField()
	 * @param string $fieldName Field name
	 * @return mixed Field value
	 */
	public function getCustomField( $fieldName ) {
		return $this->mRequestedPageFields[$fieldName];
	}

	/**
	 * Get the fields that have to be queried from the page table:
	 * the ones requested through requestField() and a few basic ones
	 * we always need
	 * @return array of field names
	 */
	public function getPageTableFields() {
		// Ensure we get minimum required fields
		// DON'T change this order
		$pageFlds = array(
			'page_namespace' => null,
			'page_title' => null,
			'page_id' => null,
		);

		if ( $this->mResolveRedirects ) {
			$pageFlds['page_is_redirect'] = null;
		}

		// only store non-default fields
		$this->mRequestedPageFields = array_diff_key( $this->mRequestedPageFields, $pageFlds );

		$pageFlds = array_merge( $pageFlds, $this->mRequestedPageFields );
		return array_keys( $pageFlds );
	}

	/**
	 * Returns an array [ns][dbkey] => page_id for all requested titles.
	 * page_id is a unique negative number in case title was not found.
	 * Invalid titles will also have negative page IDs and will be in namespace 0
	 * @return array
	 */
	public function getAllTitlesByNamespace() {
		return $this->mAllPages;
	}

	/**
	 * All Title objects provided.
	 * @return array of Title objects
	 */
	public function getTitles() {
		return $this->mTitles;
	}

	/**
	 * Returns the number of unique pages (not revisions) in the set.
	 * @return int
	 */
	public function getTitleCount() {
		return count( $this->mTitles );
	}

	/**
	 * Title objects that were found in the database.
	 * @return array page_id (int) => Title (obj)
	 */
	public function getGoodTitles() {
		return $this->mGoodTitles;
	}

	/**
	 * Returns the number of found unique pages (not revisions) in the set.
	 * @return int
	 */
	public function getGoodTitleCount() {
		return count( $this->mGoodTitles );
	}

	/**
	 * Title objects that were NOT found in the database.
	 * The array's index will be negative for each item
	 * @return array of Title objects
	 */
	public function getMissingTitles() {
		return $this->mMissingTitles;
	}

	/**
	 * Titles that were deemed invalid by Title::newFromText()
	 * The array's index will be unique and negative for each item
	 * @return array of strings (not Title objects)
	 */
	public function getInvalidTitles() {
		return $this->mInvalidTitles;
	}

	/**
	 * Page IDs that were not found in the database
	 * @return array of page IDs
	 */
	public function getMissingPageIDs() {
		return $this->mMissingPageIDs;
	}

	/**
	 * Get a list of redirect resolutions - maps a title to its redirect
	 * target, as an array of output-ready arrays
	 * @return array
	 */
	public function getRedirectTitles() {
		return $this->mRedirectTitles;
	}

	/**
	 * Get a list of redirect resolutions - maps a title to its redirect
	 * target.
	 * @param $result ApiResult
	 * @return array of prefixed_title (string) => Title object
	 * @since 1.21
	 */
	public function getRedirectTitlesAsResult( $result = null ) {
		$values = array();
		foreach ( $this->getRedirectTitles() as $titleStrFrom => $titleTo ) {
			$r = array(
				'from' => strval( $titleStrFrom ),
				'to' => $titleTo->getPrefixedText(),
			);
			if ( $titleTo->getFragment() !== '' ) {
				$r['tofragment'] = $titleTo->getFragment();
			}
			$values[] = $r;
		}
		if ( !empty( $values ) && $result ) {
			$result->setIndexedTagName( $values, 'r' );
		}
		return $values;
	}

	/**
	 * Get a list of title normalizations - maps a title to its normalized
	 * version.
	 * @return array raw_prefixed_title (string) => prefixed_title (string)
	 */
	public function getNormalizedTitles() {
		return $this->mNormalizedTitles;
	}

	/**
	 * Get a list of title normalizations - maps a title to its normalized
	 * version in the form of result array.
	 * @param $result ApiResult
	 * @return array of raw_prefixed_title (string) => prefixed_title (string)
	 * @since 1.21
	 */
	public function getNormalizedTitlesAsResult( $result = null ) {
		$values = array();
		foreach ( $this->getNormalizedTitles() as $rawTitleStr => $titleStr ) {
			$values[] = array(
				'from' => $rawTitleStr,
				'to' => $titleStr
			);
		}
		if ( !empty( $values ) && $result ) {
			$result->setIndexedTagName( $values, 'n' );
		}
		return $values;
	}

	/**
	 * Get a list of title conversions - maps a title to its converted
	 * version.
	 * @return array raw_prefixed_title (string) => prefixed_title (string)
	 */
	public function getConvertedTitles() {
		return $this->mConvertedTitles;
	}

	/**
	 * Get a list of title conversions - maps a title to its converted
	 * version as a result array.
	 * @param $result ApiResult
	 * @return array of (from, to) strings
	 * @since 1.21
	 */
	public function getConvertedTitlesAsResult( $result = null ) {
		$values = array();
		foreach ( $this->getConvertedTitles() as $rawTitleStr => $titleStr ) {
			$values[] = array(
				'from' => $rawTitleStr,
				'to' => $titleStr
			);
		}
		if ( !empty( $values ) && $result ) {
			$result->setIndexedTagName( $values, 'c' );
		}
		return $values;
	}

	/**
	 * Get a list of interwiki titles - maps a title to its interwiki
	 * prefix.
	 * @return array raw_prefixed_title (string) => interwiki_prefix (string)
	 */
	public function getInterwikiTitles() {
		return $this->mInterwikiTitles;
	}

	/**
	 * Get a list of interwiki titles - maps a title to its interwiki
	 * prefix as result.
	 * @param $result ApiResult
	 * @param $iwUrl boolean
	 * @return array raw_prefixed_title (string) => interwiki_prefix (string)
	 * @since 1.21
	 */
	public function getInterwikiTitlesAsResult( $result = null, $iwUrl = false ) {
		$values = array();
		foreach ( $this->getInterwikiTitles() as $rawTitleStr => $interwikiStr ) {
			$item = array(
				'title' => $rawTitleStr,
				'iw' => $interwikiStr,
			);
			if ( $iwUrl ) {
				$title = Title::newFromText( $rawTitleStr );
				$item['url'] = $title->getFullURL( '', false, PROTO_CURRENT );
			}
			$values[] = $item;
		}
		if ( !empty( $values ) && $result ) {
			$result->setIndexedTagName( $values, 'i' );
		}
		return $values;
	}

	/**
	 * Get the list of revision IDs (requested with the revids= parameter)
	 * @return array revID (int) => pageID (int)
	 */
	public function getRevisionIDs() {
		return $this->mGoodRevIDs;
	}

	/**
	 * Revision IDs that were not found in the database
	 * @return array of revision IDs
	 */
	public function getMissingRevisionIDs() {
		return $this->mMissingRevIDs;
	}

	/**
	 * Revision IDs that were not found in the database as result array.
	 * @param $result ApiResult
	 * @return array of revision IDs
	 * @since 1.21
	 */
	public function getMissingRevisionIDsAsResult( $result = null ) {
		$values = array();
		foreach ( $this->getMissingRevisionIDs() as $revid ) {
			$values[$revid] = array(
				'revid' => $revid
			);
		}
		if ( !empty( $values ) && $result ) {
			$result->setIndexedTagName( $values, 'rev' );
		}
		return $values;
	}

	/**
	 * Get the list of titles with negative namespace
	 * @return array Title
	 */
	public function getSpecialTitles() {
		return $this->mSpecialTitles;
	}

	/**
	 * Returns the number of revisions (requested with revids= parameter).
	 * @return int Number of revisions.
	 */
	public function getRevisionCount() {
		return count( $this->getRevisionIDs() );
	}

	/**
	 * Populate this PageSet from a list of Titles
	 * @param array $titles of Title objects
	 */
	public function populateFromTitles( $titles ) {
		$this->profileIn();
		$this->initFromTitles( $titles );
		$this->profileOut();
	}

	/**
	 * Populate this PageSet from a list of page IDs
	 * @param array $pageIDs of page IDs
	 */
	public function populateFromPageIDs( $pageIDs ) {
		$this->profileIn();
		$this->initFromPageIds( $pageIDs );
		$this->profileOut();
	}

	/**
	 * Populate this PageSet from a rowset returned from the database
	 * @param $db DatabaseBase object
	 * @param $queryResult ResultWrapper Query result object
	 */
	public function populateFromQueryResult( $db, $queryResult ) {
		$this->profileIn();
		$this->initFromQueryResult( $queryResult );
		$this->profileOut();
	}

	/**
	 * Populate this PageSet from a list of revision IDs
	 * @param array $revIDs of revision IDs
	 */
	public function populateFromRevisionIDs( $revIDs ) {
		$this->profileIn();
		$this->initFromRevIDs( $revIDs );
		$this->profileOut();
	}

	/**
	 * Extract all requested fields from the row received from the database
	 * @param $row Result row
	 */
	public function processDbRow( $row ) {
		// Store Title object in various data structures
		$title = Title::newFromRow( $row );

		$pageId = intval( $row->page_id );
		$this->mAllPages[$row->page_namespace][$row->page_title] = $pageId;
		$this->mTitles[] = $title;

		if ( $this->mResolveRedirects && $row->page_is_redirect == '1' ) {
			$this->mPendingRedirectIDs[$pageId] = $title;
		} else {
			$this->mGoodTitles[$pageId] = $title;
		}

		foreach ( $this->mRequestedPageFields as $fieldName => &$fieldValues ) {
			$fieldValues[$pageId] = $row->$fieldName;
		}
	}

	/**
	 * Do not use, does nothing, will be removed
	 * @deprecated since 1.21
	 */
	public function finishPageSetGeneration() {
		wfDeprecated( __METHOD__, '1.21' );
	}

	/**
	 * This method populates internal variables with page information
	 * based on the given array of title strings.
	 *
	 * Steps:
	 * #1 For each title, get data from `page` table
	 * #2 If page was not found in the DB, store it as missing
	 *
	 * Additionally, when resolving redirects:
	 * #3 If no more redirects left, stop.
	 * #4 For each redirect, get its target from the `redirect` table.
	 * #5 Substitute the original LinkBatch object with the new list
	 * #6 Repeat from step #1
	 *
	 * @param array $titles of Title objects or strings
	 */
	private function initFromTitles( $titles ) {
		// Get validated and normalized title objects
		$linkBatch = $this->processTitlesArray( $titles );
		if ( $linkBatch->isEmpty() ) {
			return;
		}

		$db = $this->getDB();
		$set = $linkBatch->constructSet( 'page', $db );

		// Get pageIDs data from the `page` table
		$this->profileDBIn();
		$res = $db->select( 'page', $this->getPageTableFields(), $set,
					__METHOD__ );
		$this->profileDBOut();

		// Hack: get the ns:titles stored in array(ns => array(titles)) format
		$this->initFromQueryResult( $res, $linkBatch->data, true ); // process Titles

		// Resolve any found redirects
		$this->resolvePendingRedirects();
	}

	/**
	 * Does the same as initFromTitles(), but is based on page IDs instead
	 * @param array $pageids of page IDs
	 */
	private function initFromPageIds( $pageids ) {
		if ( !$pageids ) {
			return;
		}

		$pageids = array_map( 'intval', $pageids ); // paranoia
		$remaining = array_flip( $pageids );

		$pageids = self::getPositiveIntegers( $pageids );

		$res = null;
		if ( !empty( $pageids ) ) {
			$set = array(
				'page_id' => $pageids
			);
			$db = $this->getDB();

			// Get pageIDs data from the `page` table
			$this->profileDBIn();
			$res = $db->select( 'page', $this->getPageTableFields(), $set,
						__METHOD__ );
			$this->profileDBOut();
		}

		$this->initFromQueryResult( $res, $remaining, false ); // process PageIDs

		// Resolve any found redirects
		$this->resolvePendingRedirects();
	}

	/**
	 * Iterate through the result of the query on 'page' table,
	 * and for each row create and store title object and save any extra fields requested.
	 * @param $res ResultWrapper DB Query result
	 * @param array $remaining of either pageID or ns/title elements (optional).
	 *        If given, any missing items will go to $mMissingPageIDs and $mMissingTitles
	 * @param bool $processTitles Must be provided together with $remaining.
	 *        If true, treat $remaining as an array of [ns][title]
	 *        If false, treat it as an array of [pageIDs]
	 */
	private function initFromQueryResult( $res, &$remaining = null, $processTitles = null ) {
		if ( !is_null( $remaining ) && is_null( $processTitles ) ) {
			ApiBase::dieDebug( __METHOD__, 'Missing $processTitles parameter when $remaining is provided' );
		}

		$usernames = array();
		if ( $res ) {
			foreach ( $res as $row ) {
				$pageId = intval( $row->page_id );

				// Remove found page from the list of remaining items
				if ( isset( $remaining ) ) {
					if ( $processTitles ) {
						unset( $remaining[$row->page_namespace][$row->page_title] );
					} else {
						unset( $remaining[$pageId] );
					}
				}

				// Store any extra fields requested by modules
				$this->processDbRow( $row );

				// Need gender information
				if ( MWNamespace::hasGenderDistinction( $row->page_namespace ) ) {
					$usernames[] = $row->page_title;
				}
			}
		}

		if ( isset( $remaining ) ) {
			// Any items left in the $remaining list are added as missing
			if ( $processTitles ) {
				// The remaining titles in $remaining are non-existent pages
				foreach ( $remaining as $ns => $dbkeys ) {
					foreach ( array_keys( $dbkeys ) as $dbkey ) {
						$title = Title::makeTitle( $ns, $dbkey );
						$this->mAllPages[$ns][$dbkey] = $this->mFakePageId;
						$this->mMissingTitles[$this->mFakePageId] = $title;
						$this->mFakePageId--;
						$this->mTitles[] = $title;

						// need gender information
						if ( MWNamespace::hasGenderDistinction( $ns ) ) {
							$usernames[] = $dbkey;
						}
					}
				}
			} else {
				// The remaining pageids do not exist
				if ( !$this->mMissingPageIDs ) {
					$this->mMissingPageIDs = array_keys( $remaining );
				} else {
					$this->mMissingPageIDs = array_merge( $this->mMissingPageIDs, array_keys( $remaining ) );
				}
			}
		}

		// Get gender information
		$genderCache = GenderCache::singleton();
		$genderCache->doQuery( $usernames, __METHOD__ );
	}

	/**
	 * Does the same as initFromTitles(), but is based on revision IDs
	 * instead
	 * @param array $revids of revision IDs
	 */
	private function initFromRevIDs( $revids ) {
		if ( !$revids ) {
			return;
		}

		$revids = array_map( 'intval', $revids ); // paranoia
		$db = $this->getDB();
		$pageids = array();
		$remaining = array_flip( $revids );

		$revids = self::getPositiveIntegers( $revids );

		if ( !empty( $revids ) ) {
			$tables = array( 'revision', 'page' );
			$fields = array( 'rev_id', 'rev_page' );
			$where = array( 'rev_id' => $revids, 'rev_page = page_id' );

			// Get pageIDs data from the `page` table
			$this->profileDBIn();
			$res = $db->select( $tables, $fields, $where, __METHOD__ );
			foreach ( $res as $row ) {
				$revid = intval( $row->rev_id );
				$pageid = intval( $row->rev_page );
				$this->mGoodRevIDs[$revid] = $pageid;
				$pageids[$pageid] = '';
				unset( $remaining[$revid] );
			}
			$this->profileDBOut();
		}

		$this->mMissingRevIDs = array_keys( $remaining );

		// Populate all the page information
		$this->initFromPageIds( array_keys( $pageids ) );
	}

	/**
	 * Resolve any redirects in the result if redirect resolution was
	 * requested. This function is called repeatedly until all redirects
	 * have been resolved.
	 */
	private function resolvePendingRedirects() {
		if ( $this->mResolveRedirects ) {
			$db = $this->getDB();
			$pageFlds = $this->getPageTableFields();

			// Repeat until all redirects have been resolved
			// The infinite loop is prevented by keeping all known pages in $this->mAllPages
			while ( $this->mPendingRedirectIDs ) {
				// Resolve redirects by querying the pagelinks table, and repeat the process
				// Create a new linkBatch object for the next pass
				$linkBatch = $this->getRedirectTargets();

				if ( $linkBatch->isEmpty() ) {
					break;
				}

				$set = $linkBatch->constructSet( 'page', $db );
				if ( $set === false ) {
					break;
				}

				// Get pageIDs data from the `page` table
				$this->profileDBIn();
				$res = $db->select( 'page', $pageFlds, $set, __METHOD__ );
				$this->profileDBOut();

				// Hack: get the ns:titles stored in array(ns => array(titles)) format
				$this->initFromQueryResult( $res, $linkBatch->data, true );
			}
		}
	}

	/**
	 * Get the targets of the pending redirects from the database
	 *
	 * Also creates entries in the redirect table for redirects that don't
	 * have one.
	 * @return LinkBatch
	 */
	private function getRedirectTargets() {
		$lb = new LinkBatch();
		$db = $this->getDB();

		$this->profileDBIn();
		$res = $db->select(
			'redirect',
			array(
				'rd_from',
				'rd_namespace',
				'rd_fragment',
				'rd_interwiki',
				'rd_title'
			), array( 'rd_from' => array_keys( $this->mPendingRedirectIDs ) ),
			__METHOD__
		);
		$this->profileDBOut();
		foreach ( $res as $row ) {
			$rdfrom = intval( $row->rd_from );
			$from = $this->mPendingRedirectIDs[$rdfrom]->getPrefixedText();
			$to = Title::makeTitle( $row->rd_namespace, $row->rd_title, $row->rd_fragment, $row->rd_interwiki );
			unset( $this->mPendingRedirectIDs[$rdfrom] );
			if ( !$to->isExternal() && !isset( $this->mAllPages[$row->rd_namespace][$row->rd_title] ) ) {
				$lb->add( $row->rd_namespace, $row->rd_title );
			}
			$this->mRedirectTitles[$from] = $to;
		}

		if ( $this->mPendingRedirectIDs ) {
			// We found pages that aren't in the redirect table
			// Add them
			foreach ( $this->mPendingRedirectIDs as $id => $title ) {
				$page = WikiPage::factory( $title );
				$rt = $page->insertRedirect();
				if ( !$rt ) {
					// What the hell. Let's just ignore this
					continue;
				}
				$lb->addObj( $rt );
				$this->mRedirectTitles[$title->getPrefixedText()] = $rt;
				unset( $this->mPendingRedirectIDs[$id] );
			}
		}
		return $lb;
	}

	/**
	 * Get the cache mode for the data generated by this module.
	 * All PageSet users should take into account whether this returns a more-restrictive
	 * cache mode than the using module itself. For possible return values and other
	 * details about cache modes, see ApiMain::setCacheMode()
	 *
	 * Public caching will only be allowed if *all* the modules that supply
	 * data for a given request return a cache mode of public.
	 *
	 * @param $params
	 * @return string
	 * @since 1.21
	 */
	public function getCacheMode( $params = null ) {
		return $this->mCacheMode;
	}

	/**
	 * Given an array of title strings, convert them into Title objects.
	 * Alternatively, an array of Title objects may be given.
	 * This method validates access rights for the title,
	 * and appends normalization values to the output.
	 *
	 * @param array $titles of Title objects or strings
	 * @return LinkBatch
	 */
	private function processTitlesArray( $titles ) {
		$usernames = array();
		$linkBatch = new LinkBatch();

		foreach ( $titles as $title ) {
			if ( is_string( $title ) ) {
				$titleObj = Title::newFromText( $title, $this->mDefaultNamespace );
			} else {
				$titleObj = $title;
			}
			if ( !$titleObj ) {
				// Handle invalid titles gracefully
				$this->mAllPages[0][$title] = $this->mFakePageId;
				$this->mInvalidTitles[$this->mFakePageId] = $title;
				$this->mFakePageId--;
				continue; // There's nothing else we can do
			}
			$unconvertedTitle = $titleObj->getPrefixedText();
			$titleWasConverted = false;
			if ( $titleObj->isExternal() ) {
				// This title is an interwiki link.
				$this->mInterwikiTitles[$unconvertedTitle] = $titleObj->getInterwiki();
			} else {
				// Variants checking
				global $wgContLang;
				if ( $this->mConvertTitles &&
						count( $wgContLang->getVariants() ) > 1 &&
						!$titleObj->exists() ) {
					// Language::findVariantLink will modify titleText and titleObj into
					// the canonical variant if possible
					$titleText = is_string( $title ) ? $title : $titleObj->getPrefixedText();
					$wgContLang->findVariantLink( $titleText, $titleObj );
					$titleWasConverted = $unconvertedTitle !== $titleObj->getPrefixedText();
				}

				if ( $titleObj->getNamespace() < 0 ) {
					// Handle Special and Media pages
					$titleObj = $titleObj->fixSpecialName();
					$this->mSpecialTitles[$this->mFakePageId] = $titleObj;
					$this->mFakePageId--;
				} else {
					// Regular page
					$linkBatch->addObj( $titleObj );
				}
			}

			// Make sure we remember the original title that was
			// given to us. This way the caller can correlate new
			// titles with the originally requested when e.g. the
			// namespace is localized or the capitalization is
			// different
			if ( $titleWasConverted ) {
				$this->mConvertedTitles[$unconvertedTitle] = $titleObj->getPrefixedText();
				// In this case the page can't be Special.
				if ( is_string( $title ) && $title !== $unconvertedTitle ) {
					$this->mNormalizedTitles[$title] = $unconvertedTitle;
				}
			} elseif ( is_string( $title ) && $title !== $titleObj->getPrefixedText() ) {
				$this->mNormalizedTitles[$title] = $titleObj->getPrefixedText();
			}

			// Need gender information
			if ( MWNamespace::hasGenderDistinction( $titleObj->getNamespace() ) ) {
				$usernames[] = $titleObj->getText();
			}
		}
		// Get gender information
		$genderCache = GenderCache::singleton();
		$genderCache->doQuery( $usernames, __METHOD__ );

		return $linkBatch;
	}

	/**
	 * Get the database connection (read-only)
	 * @return DatabaseBase
	 */
	protected function getDB() {
		return $this->mDbSource->getDB();
	}

	/**
	 * Returns the input array of integers with all values < 0 removed
	 *
	 * @param $array array
	 * @return array
	 */
	private static function getPositiveIntegers( $array ) {
		// bug 25734 API: possible issue with revids validation
		// It seems with a load of revision rows, MySQL gets upset
		// Remove any < 0 integers, as they can't be valid
		foreach ( $array as $i => $int ) {
			if ( $int < 0 ) {
				unset( $array[$i] );
			}
		}

		return $array;
	}

	public function getAllowedParams( $flags = 0 ) {
		$result = array(
			'titles' => array(
				ApiBase::PARAM_ISMULTI => true
			),
			'pageids' => array(
				ApiBase::PARAM_TYPE => 'integer',
				ApiBase::PARAM_ISMULTI => true
			),
			'revids' => array(
				ApiBase::PARAM_TYPE => 'integer',
				ApiBase::PARAM_ISMULTI => true
			),
			'redirects' => false,
			'converttitles' => false,
		);
		if ( $this->mAllowGenerator ) {
			if ( $flags & ApiBase::GET_VALUES_FOR_HELP ) {
				$result['generator'] = array(
					ApiBase::PARAM_TYPE => $this->getGenerators()
				);
			} else {
				$result['generator'] = null;
			}
		}
		return $result;
	}

	private static $generators = null;

	/**
	 * Get an array of all available generators
	 * @return array
	 */
	private function getGenerators() {
		if ( self::$generators === null ) {
			$query = $this->mDbSource;
			if ( !( $query instanceof ApiQuery ) ) {
				// If the parent container of this pageset is not ApiQuery,
				// we must create it to get module manager
				$query = $this->getMain()->getModuleManager()->getModule( 'query' );
			}
			$gens = array();
			$mgr = $query->getModuleManager();
			foreach ( $mgr->getNamesWithClasses() as $name => $class ) {
				if ( is_subclass_of( $class, 'ApiQueryGeneratorBase' ) ) {
					$gens[] = $name;
				}
			}
			sort( $gens );
			self::$generators = $gens;
		}
		return self::$generators;
	}

	public function getParamDescription() {
		return array(
			'titles' => 'A list of titles to work on',
			'pageids' => 'A list of page IDs to work on',
			'revids' => 'A list of revision IDs to work on',
			'generator' => array( 'Get the list of pages to work on by executing the specified query module.',
				'NOTE: generator parameter names must be prefixed with a \'g\', see examples' ),
			'redirects' => 'Automatically resolve redirects',
			'converttitles' => array( 'Convert titles to other variants if necessary. Only works if the wiki\'s content language supports variant conversion.',
				'Languages that support variant conversion include ' . implode( ', ', LanguageConverter::$languagesWithVariants ) ),
		);
	}

	public function getPossibleErrors() {
		return array_merge( parent::getPossibleErrors(), array(
			array( 'code' => 'multisource', 'info' => "Cannot use 'pageids' at the same time as 'dataSource'" ),
			array( 'code' => 'multisource', 'info' => "Cannot use 'revids' at the same time as 'dataSource'" ),
			array( 'code' => 'badgenerator', 'info' => 'Module $generatorName cannot be used as a generator' ),
		) );
	}
}