includes/WatchedItemStore.php

   1 <?php
   2
   3 use Wikimedia\Assert\Assert;
   4
   5 /**
   6  * Storage layer class for WatchedItems.
   7  * Database interaction.
   8  *
   9  * @author Addshore
  10  *
  11  * @since 1.27
  12  */
  13 class WatchedItemStore {
  14
  15         /**
  16          * @var LoadBalancer
  17          */
  18         private $loadBalancer;
  19
  20         /**
  21          * @var HashBagOStuff
  22          */
  23         private $cache;
  24
  25         /**
  26          * @var array[] Looks like $cacheIndex[Namespace ID][Target DB Key][User Id] => 'key'
  27          * The index is needed so that on mass changes all relevant items can be un-cached.
  28          * For example: Clearing a users watchlist of all items or updating notification timestamps
  29          *              for all users watching a single target.
  30          */
  31         private $cacheIndex = [];
  32
  33         /**
  34          * @var callable|null
  35          */
  36         private $deferredUpdatesAddCallableUpdateCallback;
  37
  38         /**
  39          * @var callable|null
  40          */
  41         private $revisionGetTimestampFromIdCallback;
  42
  43         /**
  44          * @var self|null
  45          */
  46         private static $instance;
  47
  48         /**
  49          * @param LoadBalancer $loadBalancer
  50          * @param HashBagOStuff $cache
  51          */
  52         public function __construct(
  53                 LoadBalancer $loadBalancer,
  54                 HashBagOStuff $cache
  55         ) {
  56                 $this->loadBalancer = $loadBalancer;
  57                 $this->cache = $cache;
  58                 $this->deferredUpdatesAddCallableUpdateCallback = [ 'DeferredUpdates', 'addCallableUpdate' ];
  59                 $this->revisionGetTimestampFromIdCallback = [ 'Revision', 'getTimestampFromId' ];
  60         }
  61
  62         /**
  63          * Overrides the DeferredUpdates::addCallableUpdate callback
  64          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
  65          *
  66          * @param callable $callback
  67          *
  68          * @see DeferredUpdates::addCallableUpdate for callback signiture
  69          *
  70          * @return ScopedCallback to reset the overridden value
  71          * @throws MWException
  72          */
  73         public function overrideDeferredUpdatesAddCallableUpdateCallback( $callback ) {
  74                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
  75                         throw new MWException(
  76                                 'Cannot override DeferredUpdates::addCallableUpdate callback in operation.'
  77                         );
  78                 }
  79                 Assert::parameterType( 'callable', $callback, '$callback' );
  80
  81                 $previousValue = $this->deferredUpdatesAddCallableUpdateCallback;
  82                 $this->deferredUpdatesAddCallableUpdateCallback = $callback;
  83                 return new ScopedCallback( function() use ( $previousValue ) {
  84                         $this->deferredUpdatesAddCallableUpdateCallback = $previousValue;
  85                 } );
  86         }
  87
  88         /**
  89          * Overrides the Revision::getTimestampFromId callback
  90          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
  91          *
  92          * @param callable $callback
  93          * @see Revision::getTimestampFromId for callback signiture
  94          *
  95          * @return ScopedCallback to reset the overridden value
  96          * @throws MWException
  97          */
  98         public function overrideRevisionGetTimestampFromIdCallback( $callback ) {
  99                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 100                         throw new MWException(
 101                                 'Cannot override Revision::getTimestampFromId callback in operation.'
 102                         );
 103                 }
 104                 Assert::parameterType( 'callable', $callback, '$callback' );
 105
 106                 $previousValue = $this->revisionGetTimestampFromIdCallback;
 107                 $this->revisionGetTimestampFromIdCallback = $callback;
 108                 return new ScopedCallback( function() use ( $previousValue ) {
 109                         $this->revisionGetTimestampFromIdCallback = $previousValue;
 110                 } );
 111         }
 112
 113         /**
 114          * Overrides the default instance of this class
 115          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
 116          *
 117          * If this method is used it MUST also be called with null after a test to ensure a new
 118          * default instance is created next time getDefaultInstance is called.
 119          *
 120          * @param WatchedItemStore|null $store
 121          *
 122          * @return ScopedCallback to reset the overridden value
 123          * @throws MWException
 124          */
 125         public static function overrideDefaultInstance( WatchedItemStore $store = null ) {
 126                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 127                         throw new MWException(
 128                                 'Cannot override ' . __CLASS__ . 'default instance in operation.'
 129                         );
 130                 }
 131
 132                 $previousValue = self::$instance;
 133                 self::$instance = $store;
 134                 return new ScopedCallback( function() use ( $previousValue ) {
 135                         self::$instance = $previousValue;
 136                 } );
 137         }
 138
 139         /**
 140          * @return self
 141          */
 142         public static function getDefaultInstance() {
 143                 if ( !self::$instance ) {
 144                         self::$instance = new self(
 145                                 wfGetLB(),
 146                                 new HashBagOStuff( [ 'maxKeys' => 100 ] )
 147                         );
 148                 }
 149                 return self::$instance;
 150         }
 151
 152         private function getCacheKey( User $user, LinkTarget $target ) {
 153                 return $this->cache->makeKey(
 154                         (string)$target->getNamespace(),
 155                         $target->getDBkey(),
 156                         (string)$user->getId()
 157                 );
 158         }
 159
 160         private function cache( WatchedItem $item ) {
 161                 $user = $item->getUser();
 162                 $target = $item->getLinkTarget();
 163                 $key = $this->getCacheKey( $user, $target );
 164                 $this->cache->set( $key, $item );
 165                 $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] = $key;
 166         }
 167
 168         private function uncache( User $user, LinkTarget $target ) {
 169                 $this->cache->delete( $this->getCacheKey( $user, $target ) );
 170                 unset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] );
 171         }
 172
 173         private function uncacheLinkTarget( LinkTarget $target ) {
 174                 if ( !isset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] ) ) {
 175                         return;
 176                 }
 177                 foreach ( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] as $key ) {
 178                         $this->cache->delete( $key );
 179                 }
 180         }
 181
 182         /**
 183          * @param User $user
 184          * @param LinkTarget $target
 185          *
 186          * @return WatchedItem|null
 187          */
 188         private function getCached( User $user, LinkTarget $target ) {
 189                 return $this->cache->get( $this->getCacheKey( $user, $target ) );
 190         }
 191
 192         /**
 193          * Return an array of conditions to select or update the appropriate database
 194          * row.
 195          *
 196          * @param User $user
 197          * @param LinkTarget $target
 198          *
 199          * @return array
 200          */
 201         private function dbCond( User $user, LinkTarget $target ) {
 202                 return [
 203                         'wl_user' => $user->getId(),
 204                         'wl_namespace' => $target->getNamespace(),
 205                         'wl_title' => $target->getDBkey(),
 206                 ];
 207         }
 208
 209         /**
 210          * @param int $slaveOrMaster DB_MASTER or DB_SLAVE
 211          *
 212          * @return DatabaseBase
 213          * @throws MWException
 214          */
 215         private function getConnection( $slaveOrMaster ) {
 216                 return $this->loadBalancer->getConnection( $slaveOrMaster, [ 'watchlist' ] );
 217         }
 218
 219         /**
 220          * @param DatabaseBase $connection
 221          *
 222          * @throws MWException
 223          */
 224         private function reuseConnection( $connection ) {
 225                 $this->loadBalancer->reuseConnection( $connection );
 226         }
 227
 228         /**
 229          * @param LinkTarget $target
 230          *
 231          * @return int
 232          */
 233         public function countWatchers( LinkTarget $target ) {
 234                 $dbr = $this->getConnection( DB_SLAVE );
 235                 $return = (int)$dbr->selectField(
 236                         'watchlist',
 237                         'COUNT(*)',
 238                         [
 239                                 'wl_namespace' => $target->getNamespace(),
 240                                 'wl_title' => $target->getDBkey(),
 241                         ],
 242                         __METHOD__
 243                 );
 244                 $this->reuseConnection( $dbr );
 245
 246                 return $return;
 247         }
 248
 249         /**
 250          * Number of page watchers who also visited a "recent" edit
 251          *
 252          * @param LinkTarget $target
 253          * @param mixed $threshold timestamp accepted by wfTimestamp
 254          *
 255          * @return int
 256          * @throws DBUnexpectedError
 257          * @throws MWException
 258          */
 259         public function countVisitingWatchers( LinkTarget $target, $threshold ) {
 260                 $dbr = $this->getConnection( DB_SLAVE );
 261                 $visitingWatchers = (int)$dbr->selectField(
 262                         'watchlist',
 263                         'COUNT(*)',
 264                         [
 265                                 'wl_namespace' => $target->getNamespace(),
 266                                 'wl_title' => $target->getDBkey(),
 267                                 'wl_notificationtimestamp >= ' .
 268                                 $dbr->addQuotes( $dbr->timestamp( $threshold ) ) .
 269                                 ' OR wl_notificationtimestamp IS NULL'
 270                         ],
 271                         __METHOD__
 272                 );
 273                 $this->reuseConnection( $dbr );
 274
 275                 return $visitingWatchers;
 276         }
 277
 278         /**
 279          * @param LinkTarget[] $targets
 280          * @param array $options Allowed keys:
 281          *        'minimumWatchers' => int
 282          *
 283          * @return array multi dimensional like $return[$namespaceId][$titleString] = int $watchers
 284          *         All targets will be present in the result. 0 either means no watchers or the number
 285          *         of watchers was below the minimumWatchers option if passed.
 286          */
 287         public function countWatchersMultiple( array $targets, array $options = [] ) {
 288                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 289
 290                 $dbr = $this->getConnection( DB_SLAVE );
 291
 292                 if ( array_key_exists( 'minimumWatchers', $options ) ) {
 293                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$options['minimumWatchers'];
 294                 }
 295
 296                 $lb = new LinkBatch( $targets );
 297                 $res = $dbr->select(
 298                         'watchlist',
 299                         [ 'wl_title', 'wl_namespace', 'watchers' => 'COUNT(*)' ],
 300                         [ $lb->constructSet( 'wl', $dbr ) ],
 301                         __METHOD__,
 302                         $dbOptions
 303                 );
 304
 305                 $this->reuseConnection( $dbr );
 306
 307                 $watchCounts = [];
 308                 foreach ( $targets as $linkTarget ) {
 309                         $watchCounts[$linkTarget->getNamespace()][$linkTarget->getDBkey()] = 0;
 310                 }
 311
 312                 foreach ( $res as $row ) {
 313                         $watchCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 314                 }
 315
 316                 return $watchCounts;
 317         }
 318
 319         /**
 320          * Get an item (may be cached)
 321          *
 322          * @param User $user
 323          * @param LinkTarget $target
 324          *
 325          * @return WatchedItem|false
 326          */
 327         public function getWatchedItem( User $user, LinkTarget $target ) {
 328                 if ( $user->isAnon() ) {
 329                         return false;
 330                 }
 331
 332                 $cached = $this->getCached( $user, $target );
 333                 if ( $cached ) {
 334                         return $cached;
 335                 }
 336                 return $this->loadWatchedItem( $user, $target );
 337         }
 338
 339         /**
 340          * Loads an item from the db
 341          *
 342          * @param User $user
 343          * @param LinkTarget $target
 344          *
 345          * @return WatchedItem|false
 346          */
 347         public function loadWatchedItem( User $user, LinkTarget $target ) {
 348                 // Only loggedin user can have a watchlist
 349                 if ( $user->isAnon() ) {
 350                         return false;
 351                 }
 352
 353                 $dbr = $this->getConnection( DB_SLAVE );
 354                 $row = $dbr->selectRow(
 355                         'watchlist',
 356                         'wl_notificationtimestamp',
 357                         $this->dbCond( $user, $target ),
 358                         __METHOD__
 359                 );
 360                 $this->reuseConnection( $dbr );
 361
 362                 if ( !$row ) {
 363                         return false;
 364                 }
 365
 366                 $item = new WatchedItem(
 367                         $user,
 368                         $target,
 369                         $row->wl_notificationtimestamp
 370                 );
 371                 $this->cache( $item );
 372
 373                 return $item;
 374         }
 375
 376         /**
 377          * Must be called separately for Subject & Talk namespaces
 378          *
 379          * @param User $user
 380          * @param LinkTarget $target
 381          *
 382          * @return bool
 383          */
 384         public function isWatched( User $user, LinkTarget $target ) {
 385                 return (bool)$this->getWatchedItem( $user, $target );
 386         }
 387
 388         /**
 389          * Must be called separately for Subject & Talk namespaces
 390          *
 391          * @param User $user
 392          * @param LinkTarget $target
 393          */
 394         public function addWatch( User $user, LinkTarget $target ) {
 395                 $this->addWatchBatch( [ [ $user, $target ] ] );
 396         }
 397
 398         /**
 399          * @param array[] $userTargetCombinations array of arrays containing [0] => User [1] => LinkTarget
 400          *
 401          * @return bool success
 402          */
 403         public function addWatchBatch( array $userTargetCombinations ) {
 404                 if ( $this->loadBalancer->getReadOnlyReason() !== false ) {
 405                         return false;
 406                 }
 407
 408                 $rows = [];
 409                 foreach ( $userTargetCombinations as list( $user, $target ) ) {
 410                         /**
 411                          * @var User $user
 412                          * @var LinkTarget $target
 413                          */
 414
 415                         // Only loggedin user can have a watchlist
 416                         if ( $user->isAnon() ) {
 417                                 continue;
 418                         }
 419                         $rows[] = [
 420                                 'wl_user' => $user->getId(),
 421                                 'wl_namespace' => $target->getNamespace(),
 422                                 'wl_title' => $target->getDBkey(),
 423                                 'wl_notificationtimestamp' => null,
 424                         ];
 425                         $this->uncache( $user, $target );
 426                 }
 427
 428                 if ( !$rows ) {
 429                         return false;
 430                 }
 431
 432                 $dbw = $this->getConnection( DB_MASTER );
 433                 foreach ( array_chunk( $rows, 100 ) as $toInsert ) {
 434                         // Use INSERT IGNORE to avoid overwriting the notification timestamp
 435                         // if there's already an entry for this page
 436                         $dbw->insert( 'watchlist', $toInsert, __METHOD__, 'IGNORE' );
 437                 }
 438                 $this->reuseConnection( $dbw );
 439
 440                 return true;
 441         }
 442
 443         /**
 444          * Removes the an entry for the User watching the LinkTarget
 445          * Must be called separately for Subject & Talk namespaces
 446          *
 447          * @param User $user
 448          * @param LinkTarget $target
 449          *
 450          * @return bool success
 451          * @throws DBUnexpectedError
 452          * @throws MWException
 453          */
 454         public function removeWatch( User $user, LinkTarget $target ) {
 455                 // Only logged in user can have a watchlist
 456                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 457                         return false;
 458                 }
 459
 460                 $this->uncache( $user, $target );
 461
 462                 $dbw = $this->getConnection( DB_MASTER );
 463                 $dbw->delete( 'watchlist',
 464                         [
 465                                 'wl_user' => $user->getId(),
 466                                 'wl_namespace' => $target->getNamespace(),
 467                                 'wl_title' => $target->getDBkey(),
 468                         ], __METHOD__
 469                 );
 470                 $success = (bool)$dbw->affectedRows();
 471                 $this->reuseConnection( $dbw );
 472
 473                 return $success;
 474         }
 475
 476         /**
 477          * @param User $editor The editor that triggered the update. Their notification
 478          *  timestamp will not be updated(they have already seen it)
 479          * @param LinkTarget $target The target to update timestamps for
 480          * @param string $timestamp Set the update timestamp to this value
 481          *
 482          * @return int[] Array of user IDs the timestamp has been updated for
 483          */
 484         public function updateNotificationTimestamp( User $editor, LinkTarget $target, $timestamp ) {
 485                 $dbw = $this->getConnection( DB_MASTER );
 486                 $res = $dbw->select( [ 'watchlist' ],
 487                         [ 'wl_user' ],
 488                         [
 489                                 'wl_user != ' . intval( $editor->getId() ),
 490                                 'wl_namespace' => $target->getNamespace(),
 491                                 'wl_title' => $target->getDBkey(),
 492                                 'wl_notificationtimestamp IS NULL',
 493                         ], __METHOD__
 494                 );
 495
 496                 $watchers = [];
 497                 foreach ( $res as $row ) {
 498                         $watchers[] = intval( $row->wl_user );
 499                 }
 500
 501                 if ( $watchers ) {
 502                         // Update wl_notificationtimestamp for all watching users except the editor
 503                         $fname = __METHOD__;
 504                         $dbw->onTransactionIdle(
 505                                 function () use ( $dbw, $timestamp, $watchers, $target, $fname ) {
 506                                         $dbw->update( 'watchlist',
 507                                                 [ /* SET */
 508                                                         'wl_notificationtimestamp' => $dbw->timestamp( $timestamp )
 509                                                 ], [ /* WHERE */
 510                                                         'wl_user' => $watchers,
 511                                                         'wl_namespace' => $target->getNamespace(),
 512                                                         'wl_title' => $target->getDBkey(),
 513                                                 ], $fname
 514                                         );
 515                                         $this->uncacheLinkTarget( $target );
 516                                 }
 517                         );
 518                 }
 519
 520                 $this->reuseConnection( $dbw );
 521
 522                 return $watchers;
 523         }
 524
 525         /**
 526          * Reset the notification timestamp of this entry
 527          *
 528          * @param User $user
 529          * @param Title $title
 530          * @param string $force Whether to force the write query to be executed even if the
 531          *    page is not watched or the notification timestamp is already NULL.
 532          *    'force' in order to force
 533          * @param int $oldid The revision id being viewed. If not given or 0, latest revision is assumed.
 534          *
 535          * @return bool success
 536          */
 537         public function resetNotificationTimestamp( User $user, Title $title, $force = '', $oldid = 0 ) {
 538                 // Only loggedin user can have a watchlist
 539                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 540                         return false;
 541                 }
 542
 543                 $item = null;
 544                 if ( $force != 'force' ) {
 545                         $item = $this->loadWatchedItem( $user, $title );
 546                         if ( !$item || $item->getNotificationTimestamp() === null ) {
 547                                 return false;
 548                         }
 549                 }
 550
 551                 // If the page is watched by the user (or may be watched), update the timestamp
 552                 $job = new ActivityUpdateJob(
 553                         $title,
 554                         [
 555                                 'type'      => 'updateWatchlistNotification',
 556                                 'userid'    => $user->getId(),
 557                                 'notifTime' => $this->getNotificationTimestamp( $user, $title, $item, $force, $oldid ),
 558                                 'curTime'   => time()
 559                         ]
 560                 );
 561
 562                 // Try to run this post-send
 563                 // Calls DeferredUpdates::addCallableUpdate in normal operation
 564                 call_user_func(
 565                         $this->deferredUpdatesAddCallableUpdateCallback,
 566                         function() use ( $job ) {
 567                                 $job->run();
 568                         }
 569                 );
 570
 571                 $this->uncache( $user, $title );
 572
 573                 return true;
 574         }
 575
 576         private function getNotificationTimestamp( User $user, Title $title, $item, $force, $oldid ) {
 577                 if ( !$oldid ) {
 578                         // No oldid given, assuming latest revision; clear the timestamp.
 579                         return null;
 580                 }
 581
 582                 if ( !$title->getNextRevisionID( $oldid ) ) {
 583                         // Oldid given and is the latest revision for this title; clear the timestamp.
 584                         return null;
 585                 }
 586
 587                 if ( $item === null ) {
 588                         $item = $this->loadWatchedItem( $user, $title );
 589                 }
 590
 591                 if ( !$item ) {
 592                         // This can only happen if $force is enabled.
 593                         return null;
 594                 }
 595
 596                 // Oldid given and isn't the latest; update the timestamp.
 597                 // This will result in no further notification emails being sent!
 598                 // Calls Revision::getTimestampFromId in normal operation
 599                 $notificationTimestamp = call_user_func(
 600                         $this->revisionGetTimestampFromIdCallback,
 601                         $title,
 602                         $oldid
 603                 );
 604
 605                 // We need to go one second to the future because of various strict comparisons
 606                 // throughout the codebase
 607                 $ts = new MWTimestamp( $notificationTimestamp );
 608                 $ts->timestamp->add( new DateInterval( 'PT1S' ) );
 609                 $notificationTimestamp = $ts->getTimestamp( TS_MW );
 610
 611                 if ( $notificationTimestamp < $item->getNotificationTimestamp() ) {
 612                         if ( $force != 'force' ) {
 613                                 return false;
 614                         } else {
 615                                 // This is a little silly…
 616                                 return $item->getNotificationTimestamp();
 617                         }
 618                 }
 619
 620                 return $notificationTimestamp;
 621         }
 622
 623         /**
 624          * @param User $user
 625          * @param int $unreadLimit
 626          *
 627          * @return int|bool The number of unread notifications
 628          *                  true if greater than or equal to $unreadLimit
 629          */
 630         public function countUnreadNotifications( User $user, $unreadLimit = null ) {
 631                 $queryOptions = [];
 632                 if ( $unreadLimit !== null ) {
 633                         $unreadLimit = (int)$unreadLimit;
 634                         $queryOptions['LIMIT'] = $unreadLimit;
 635                 }
 636
 637                 $dbr = $this->getConnection( DB_SLAVE );
 638                 $rowCount = $dbr->selectRowCount(
 639                         'watchlist',
 640                         '1',
 641                         [
 642                                 'wl_user' => $user->getId(),
 643                                 'wl_notificationtimestamp IS NOT NULL',
 644                         ],
 645                         __METHOD__,
 646                         $queryOptions
 647                 );
 648                 $this->reuseConnection( $dbr );
 649
 650                 if ( !isset( $unreadLimit ) ) {
 651                         return $rowCount;
 652                 }
 653
 654                 if ( $rowCount >= $unreadLimit ) {
 655                         return true;
 656                 }
 657
 658                 return $rowCount;
 659         }
 660
 661         /**
 662          * Check if the given title already is watched by the user, and if so
 663          * add a watch for the new title.
 664          *
 665          * To be used for page renames and such.
 666          *
 667          * @param LinkTarget $oldTarget
 668          * @param LinkTarget $newTarget
 669          */
 670         public function duplicateAllAssociatedEntries( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 671                 if ( !$oldTarget instanceof Title ) {
 672                         $oldTarget = Title::newFromLinkTarget( $oldTarget );
 673                 }
 674                 if ( !$newTarget instanceof Title ) {
 675                         $newTarget = Title::newFromLinkTarget( $newTarget );
 676                 }
 677
 678                 $this->duplicateEntry( $oldTarget->getSubjectPage(), $newTarget->getSubjectPage() );
 679                 $this->duplicateEntry( $oldTarget->getTalkPage(), $newTarget->getTalkPage() );
 680         }
 681
 682         /**
 683          * Check if the given title already is watched by the user, and if so
 684          * add a watch for the new title.
 685          *
 686          * To be used for page renames and such.
 687          * This must be called separately for Subject and Talk pages
 688          *
 689          * @param LinkTarget $oldTarget
 690          * @param LinkTarget $newTarget
 691          */
 692         public function duplicateEntry( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 693                 $dbw = $this->getConnection( DB_MASTER );
 694
 695                 $result = $dbw->select(
 696                         'watchlist',
 697                         [ 'wl_user', 'wl_notificationtimestamp' ],
 698                         [
 699                                 'wl_namespace' => $oldTarget->getNamespace(),
 700                                 'wl_title' => $oldTarget->getDBkey(),
 701                         ],
 702                         __METHOD__,
 703                         [ 'FOR UPDATE' ]
 704                 );
 705
 706                 $newNamespace = $newTarget->getNamespace();
 707                 $newDBkey = $newTarget->getDBkey();
 708
 709                 # Construct array to replace into the watchlist
 710                 $values = [];
 711                 foreach ( $result as $row ) {
 712                         $values[] = [
 713                                 'wl_user' => $row->wl_user,
 714                                 'wl_namespace' => $newNamespace,
 715                                 'wl_title' => $newDBkey,
 716                                 'wl_notificationtimestamp' => $row->wl_notificationtimestamp,
 717                         ];
 718                 }
 719
 720                 if ( !empty( $values ) ) {
 721                         # Perform replace
 722                         # Note that multi-row replace is very efficient for MySQL but may be inefficient for
 723                         # some other DBMSes, mostly due to poor simulation by us
 724                         $dbw->replace(
 725                                 'watchlist',
 726                                 [ [ 'wl_user', 'wl_namespace', 'wl_title' ] ],
 727                                 $values,
 728                                 __METHOD__
 729                         );
 730                 }
 731
 732                 $this->reuseConnection( $dbw );
 733         }
 734
 735 }