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          * Count the number of individual items that are watched by the user.
 230          * If a subject and corresponding talk page are watched this will return 2.
 231          *
 232          * @param User $user
 233          *
 234          * @return int
 235          */
 236         public function countWatchedItems( User $user ) {
 237                 $dbr = $this->getConnection( DB_SLAVE );
 238                 $return = (int)$dbr->selectField(
 239                         'watchlist',
 240                         'COUNT(*)',
 241                         [
 242                                 'wl_user' => $user->getId()
 243                         ],
 244                         __METHOD__
 245                 );
 246                 $this->reuseConnection( $dbr );
 247
 248                 return $return;
 249         }
 250
 251         /**
 252          * @param LinkTarget $target
 253          *
 254          * @return int
 255          */
 256         public function countWatchers( LinkTarget $target ) {
 257                 $dbr = $this->getConnection( DB_SLAVE );
 258                 $return = (int)$dbr->selectField(
 259                         'watchlist',
 260                         'COUNT(*)',
 261                         [
 262                                 'wl_namespace' => $target->getNamespace(),
 263                                 'wl_title' => $target->getDBkey(),
 264                         ],
 265                         __METHOD__
 266                 );
 267                 $this->reuseConnection( $dbr );
 268
 269                 return $return;
 270         }
 271
 272         /**
 273          * Number of page watchers who also visited a "recent" edit
 274          *
 275          * @param LinkTarget $target
 276          * @param mixed $threshold timestamp accepted by wfTimestamp
 277          *
 278          * @return int
 279          * @throws DBUnexpectedError
 280          * @throws MWException
 281          */
 282         public function countVisitingWatchers( LinkTarget $target, $threshold ) {
 283                 $dbr = $this->getConnection( DB_SLAVE );
 284                 $visitingWatchers = (int)$dbr->selectField(
 285                         'watchlist',
 286                         'COUNT(*)',
 287                         [
 288                                 'wl_namespace' => $target->getNamespace(),
 289                                 'wl_title' => $target->getDBkey(),
 290                                 'wl_notificationtimestamp >= ' .
 291                                 $dbr->addQuotes( $dbr->timestamp( $threshold ) ) .
 292                                 ' OR wl_notificationtimestamp IS NULL'
 293                         ],
 294                         __METHOD__
 295                 );
 296                 $this->reuseConnection( $dbr );
 297
 298                 return $visitingWatchers;
 299         }
 300
 301         /**
 302          * @param LinkTarget[] $targets
 303          * @param array $options Allowed keys:
 304          *        'minimumWatchers' => int
 305          *
 306          * @return array multi dimensional like $return[$namespaceId][$titleString] = int $watchers
 307          *         All targets will be present in the result. 0 either means no watchers or the number
 308          *         of watchers was below the minimumWatchers option if passed.
 309          */
 310         public function countWatchersMultiple( array $targets, array $options = [] ) {
 311                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 312
 313                 $dbr = $this->getConnection( DB_SLAVE );
 314
 315                 if ( array_key_exists( 'minimumWatchers', $options ) ) {
 316                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$options['minimumWatchers'];
 317                 }
 318
 319                 $lb = new LinkBatch( $targets );
 320                 $res = $dbr->select(
 321                         'watchlist',
 322                         [ 'wl_title', 'wl_namespace', 'watchers' => 'COUNT(*)' ],
 323                         [ $lb->constructSet( 'wl', $dbr ) ],
 324                         __METHOD__,
 325                         $dbOptions
 326                 );
 327
 328                 $this->reuseConnection( $dbr );
 329
 330                 $watchCounts = [];
 331                 foreach ( $targets as $linkTarget ) {
 332                         $watchCounts[$linkTarget->getNamespace()][$linkTarget->getDBkey()] = 0;
 333                 }
 334
 335                 foreach ( $res as $row ) {
 336                         $watchCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 337                 }
 338
 339                 return $watchCounts;
 340         }
 341
 342         /**
 343          * Get an item (may be cached)
 344          *
 345          * @param User $user
 346          * @param LinkTarget $target
 347          *
 348          * @return WatchedItem|false
 349          */
 350         public function getWatchedItem( User $user, LinkTarget $target ) {
 351                 if ( $user->isAnon() ) {
 352                         return false;
 353                 }
 354
 355                 $cached = $this->getCached( $user, $target );
 356                 if ( $cached ) {
 357                         return $cached;
 358                 }
 359                 return $this->loadWatchedItem( $user, $target );
 360         }
 361
 362         /**
 363          * Loads an item from the db
 364          *
 365          * @param User $user
 366          * @param LinkTarget $target
 367          *
 368          * @return WatchedItem|false
 369          */
 370         public function loadWatchedItem( User $user, LinkTarget $target ) {
 371                 // Only loggedin user can have a watchlist
 372                 if ( $user->isAnon() ) {
 373                         return false;
 374                 }
 375
 376                 $dbr = $this->getConnection( DB_SLAVE );
 377                 $row = $dbr->selectRow(
 378                         'watchlist',
 379                         'wl_notificationtimestamp',
 380                         $this->dbCond( $user, $target ),
 381                         __METHOD__
 382                 );
 383                 $this->reuseConnection( $dbr );
 384
 385                 if ( !$row ) {
 386                         return false;
 387                 }
 388
 389                 $item = new WatchedItem(
 390                         $user,
 391                         $target,
 392                         $row->wl_notificationtimestamp
 393                 );
 394                 $this->cache( $item );
 395
 396                 return $item;
 397         }
 398
 399         /**
 400          * @param User $user
 401          * @param array $options Allowed keys:
 402          *        'forWrite' => bool defaults to false
 403          *
 404          * @return WatchedItem[]
 405          */
 406         public function getWatchedItemsForUser( User $user, array $options = [] ) {
 407                 $options += [ 'forWrite' => false ];
 408
 409                 $db = $this->getConnection( $options['forWrite'] ? DB_MASTER : DB_SLAVE );
 410                 $res = $db->select(
 411                         'watchlist',
 412                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 413                         [ 'wl_user' => $user->getId() ],
 414                         __METHOD__
 415                 );
 416                 $this->reuseConnection( $db );
 417
 418                 $watchedItems = [];
 419                 foreach ( $res as $row ) {
 420                         // todo these could all be cached at some point?
 421                         $watchedItems[] = new WatchedItem(
 422                                 $user,
 423                                 new TitleValue( (int)$row->wl_namespace, $row->wl_title ),
 424                                 $row->wl_notificationtimestamp
 425                         );
 426                 }
 427
 428                 return $watchedItems;
 429         }
 430
 431         /**
 432          * Must be called separately for Subject & Talk namespaces
 433          *
 434          * @param User $user
 435          * @param LinkTarget $target
 436          *
 437          * @return bool
 438          */
 439         public function isWatched( User $user, LinkTarget $target ) {
 440                 return (bool)$this->getWatchedItem( $user, $target );
 441         }
 442
 443         /**
 444          * Must be called separately for Subject & Talk namespaces
 445          *
 446          * @param User $user
 447          * @param LinkTarget $target
 448          */
 449         public function addWatch( User $user, LinkTarget $target ) {
 450                 $this->addWatchBatch( [ [ $user, $target ] ] );
 451         }
 452
 453         /**
 454          * @param array[] $userTargetCombinations array of arrays containing [0] => User [1] => LinkTarget
 455          *
 456          * @return bool success
 457          */
 458         public function addWatchBatch( array $userTargetCombinations ) {
 459                 if ( $this->loadBalancer->getReadOnlyReason() !== false ) {
 460                         return false;
 461                 }
 462
 463                 $rows = [];
 464                 foreach ( $userTargetCombinations as list( $user, $target ) ) {
 465                         /**
 466                          * @var User $user
 467                          * @var LinkTarget $target
 468                          */
 469
 470                         // Only loggedin user can have a watchlist
 471                         if ( $user->isAnon() ) {
 472                                 continue;
 473                         }
 474                         $rows[] = [
 475                                 'wl_user' => $user->getId(),
 476                                 'wl_namespace' => $target->getNamespace(),
 477                                 'wl_title' => $target->getDBkey(),
 478                                 'wl_notificationtimestamp' => null,
 479                         ];
 480                         $this->uncache( $user, $target );
 481                 }
 482
 483                 if ( !$rows ) {
 484                         return false;
 485                 }
 486
 487                 $dbw = $this->getConnection( DB_MASTER );
 488                 foreach ( array_chunk( $rows, 100 ) as $toInsert ) {
 489                         // Use INSERT IGNORE to avoid overwriting the notification timestamp
 490                         // if there's already an entry for this page
 491                         $dbw->insert( 'watchlist', $toInsert, __METHOD__, 'IGNORE' );
 492                 }
 493                 $this->reuseConnection( $dbw );
 494
 495                 return true;
 496         }
 497
 498         /**
 499          * Removes the an entry for the User watching the LinkTarget
 500          * Must be called separately for Subject & Talk namespaces
 501          *
 502          * @param User $user
 503          * @param LinkTarget $target
 504          *
 505          * @return bool success
 506          * @throws DBUnexpectedError
 507          * @throws MWException
 508          */
 509         public function removeWatch( User $user, LinkTarget $target ) {
 510                 // Only logged in user can have a watchlist
 511                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 512                         return false;
 513                 }
 514
 515                 $this->uncache( $user, $target );
 516
 517                 $dbw = $this->getConnection( DB_MASTER );
 518                 $dbw->delete( 'watchlist',
 519                         [
 520                                 'wl_user' => $user->getId(),
 521                                 'wl_namespace' => $target->getNamespace(),
 522                                 'wl_title' => $target->getDBkey(),
 523                         ], __METHOD__
 524                 );
 525                 $success = (bool)$dbw->affectedRows();
 526                 $this->reuseConnection( $dbw );
 527
 528                 return $success;
 529         }
 530
 531         /**
 532          * @param User $editor The editor that triggered the update. Their notification
 533          *  timestamp will not be updated(they have already seen it)
 534          * @param LinkTarget $target The target to update timestamps for
 535          * @param string $timestamp Set the update timestamp to this value
 536          *
 537          * @return int[] Array of user IDs the timestamp has been updated for
 538          */
 539         public function updateNotificationTimestamp( User $editor, LinkTarget $target, $timestamp ) {
 540                 $dbw = $this->getConnection( DB_MASTER );
 541                 $res = $dbw->select( [ 'watchlist' ],
 542                         [ 'wl_user' ],
 543                         [
 544                                 'wl_user != ' . intval( $editor->getId() ),
 545                                 'wl_namespace' => $target->getNamespace(),
 546                                 'wl_title' => $target->getDBkey(),
 547                                 'wl_notificationtimestamp IS NULL',
 548                         ], __METHOD__
 549                 );
 550
 551                 $watchers = [];
 552                 foreach ( $res as $row ) {
 553                         $watchers[] = intval( $row->wl_user );
 554                 }
 555
 556                 if ( $watchers ) {
 557                         // Update wl_notificationtimestamp for all watching users except the editor
 558                         $fname = __METHOD__;
 559                         $dbw->onTransactionIdle(
 560                                 function () use ( $dbw, $timestamp, $watchers, $target, $fname ) {
 561                                         $dbw->update( 'watchlist',
 562                                                 [ /* SET */
 563                                                         'wl_notificationtimestamp' => $dbw->timestamp( $timestamp )
 564                                                 ], [ /* WHERE */
 565                                                         'wl_user' => $watchers,
 566                                                         'wl_namespace' => $target->getNamespace(),
 567                                                         'wl_title' => $target->getDBkey(),
 568                                                 ], $fname
 569                                         );
 570                                         $this->uncacheLinkTarget( $target );
 571                                 }
 572                         );
 573                 }
 574
 575                 $this->reuseConnection( $dbw );
 576
 577                 return $watchers;
 578         }
 579
 580         /**
 581          * Reset the notification timestamp of this entry
 582          *
 583          * @param User $user
 584          * @param Title $title
 585          * @param string $force Whether to force the write query to be executed even if the
 586          *    page is not watched or the notification timestamp is already NULL.
 587          *    'force' in order to force
 588          * @param int $oldid The revision id being viewed. If not given or 0, latest revision is assumed.
 589          *
 590          * @return bool success
 591          */
 592         public function resetNotificationTimestamp( User $user, Title $title, $force = '', $oldid = 0 ) {
 593                 // Only loggedin user can have a watchlist
 594                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 595                         return false;
 596                 }
 597
 598                 $item = null;
 599                 if ( $force != 'force' ) {
 600                         $item = $this->loadWatchedItem( $user, $title );
 601                         if ( !$item || $item->getNotificationTimestamp() === null ) {
 602                                 return false;
 603                         }
 604                 }
 605
 606                 // If the page is watched by the user (or may be watched), update the timestamp
 607                 $job = new ActivityUpdateJob(
 608                         $title,
 609                         [
 610                                 'type'      => 'updateWatchlistNotification',
 611                                 'userid'    => $user->getId(),
 612                                 'notifTime' => $this->getNotificationTimestamp( $user, $title, $item, $force, $oldid ),
 613                                 'curTime'   => time()
 614                         ]
 615                 );
 616
 617                 // Try to run this post-send
 618                 // Calls DeferredUpdates::addCallableUpdate in normal operation
 619                 call_user_func(
 620                         $this->deferredUpdatesAddCallableUpdateCallback,
 621                         function() use ( $job ) {
 622                                 $job->run();
 623                         }
 624                 );
 625
 626                 $this->uncache( $user, $title );
 627
 628                 return true;
 629         }
 630
 631         private function getNotificationTimestamp( User $user, Title $title, $item, $force, $oldid ) {
 632                 if ( !$oldid ) {
 633                         // No oldid given, assuming latest revision; clear the timestamp.
 634                         return null;
 635                 }
 636
 637                 if ( !$title->getNextRevisionID( $oldid ) ) {
 638                         // Oldid given and is the latest revision for this title; clear the timestamp.
 639                         return null;
 640                 }
 641
 642                 if ( $item === null ) {
 643                         $item = $this->loadWatchedItem( $user, $title );
 644                 }
 645
 646                 if ( !$item ) {
 647                         // This can only happen if $force is enabled.
 648                         return null;
 649                 }
 650
 651                 // Oldid given and isn't the latest; update the timestamp.
 652                 // This will result in no further notification emails being sent!
 653                 // Calls Revision::getTimestampFromId in normal operation
 654                 $notificationTimestamp = call_user_func(
 655                         $this->revisionGetTimestampFromIdCallback,
 656                         $title,
 657                         $oldid
 658                 );
 659
 660                 // We need to go one second to the future because of various strict comparisons
 661                 // throughout the codebase
 662                 $ts = new MWTimestamp( $notificationTimestamp );
 663                 $ts->timestamp->add( new DateInterval( 'PT1S' ) );
 664                 $notificationTimestamp = $ts->getTimestamp( TS_MW );
 665
 666                 if ( $notificationTimestamp < $item->getNotificationTimestamp() ) {
 667                         if ( $force != 'force' ) {
 668                                 return false;
 669                         } else {
 670                                 // This is a little silly…
 671                                 return $item->getNotificationTimestamp();
 672                         }
 673                 }
 674
 675                 return $notificationTimestamp;
 676         }
 677
 678         /**
 679          * @param User $user
 680          * @param int $unreadLimit
 681          *
 682          * @return int|bool The number of unread notifications
 683          *                  true if greater than or equal to $unreadLimit
 684          */
 685         public function countUnreadNotifications( User $user, $unreadLimit = null ) {
 686                 $queryOptions = [];
 687                 if ( $unreadLimit !== null ) {
 688                         $unreadLimit = (int)$unreadLimit;
 689                         $queryOptions['LIMIT'] = $unreadLimit;
 690                 }
 691
 692                 $dbr = $this->getConnection( DB_SLAVE );
 693                 $rowCount = $dbr->selectRowCount(
 694                         'watchlist',
 695                         '1',
 696                         [
 697                                 'wl_user' => $user->getId(),
 698                                 'wl_notificationtimestamp IS NOT NULL',
 699                         ],
 700                         __METHOD__,
 701                         $queryOptions
 702                 );
 703                 $this->reuseConnection( $dbr );
 704
 705                 if ( !isset( $unreadLimit ) ) {
 706                         return $rowCount;
 707                 }
 708
 709                 if ( $rowCount >= $unreadLimit ) {
 710                         return true;
 711                 }
 712
 713                 return $rowCount;
 714         }
 715
 716         /**
 717          * Check if the given title already is watched by the user, and if so
 718          * add a watch for the new title.
 719          *
 720          * To be used for page renames and such.
 721          *
 722          * @param LinkTarget $oldTarget
 723          * @param LinkTarget $newTarget
 724          */
 725         public function duplicateAllAssociatedEntries( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 726                 if ( !$oldTarget instanceof Title ) {
 727                         $oldTarget = Title::newFromLinkTarget( $oldTarget );
 728                 }
 729                 if ( !$newTarget instanceof Title ) {
 730                         $newTarget = Title::newFromLinkTarget( $newTarget );
 731                 }
 732
 733                 $this->duplicateEntry( $oldTarget->getSubjectPage(), $newTarget->getSubjectPage() );
 734                 $this->duplicateEntry( $oldTarget->getTalkPage(), $newTarget->getTalkPage() );
 735         }
 736
 737         /**
 738          * Check if the given title already is watched by the user, and if so
 739          * add a watch for the new title.
 740          *
 741          * To be used for page renames and such.
 742          * This must be called separately for Subject and Talk pages
 743          *
 744          * @param LinkTarget $oldTarget
 745          * @param LinkTarget $newTarget
 746          */
 747         public function duplicateEntry( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 748                 $dbw = $this->getConnection( DB_MASTER );
 749
 750                 $result = $dbw->select(
 751                         'watchlist',
 752                         [ 'wl_user', 'wl_notificationtimestamp' ],
 753                         [
 754                                 'wl_namespace' => $oldTarget->getNamespace(),
 755                                 'wl_title' => $oldTarget->getDBkey(),
 756                         ],
 757                         __METHOD__,
 758                         [ 'FOR UPDATE' ]
 759                 );
 760
 761                 $newNamespace = $newTarget->getNamespace();
 762                 $newDBkey = $newTarget->getDBkey();
 763
 764                 # Construct array to replace into the watchlist
 765                 $values = [];
 766                 foreach ( $result as $row ) {
 767                         $values[] = [
 768                                 'wl_user' => $row->wl_user,
 769                                 'wl_namespace' => $newNamespace,
 770                                 'wl_title' => $newDBkey,
 771                                 'wl_notificationtimestamp' => $row->wl_notificationtimestamp,
 772                         ];
 773                 }
 774
 775                 if ( !empty( $values ) ) {
 776                         # Perform replace
 777                         # Note that multi-row replace is very efficient for MySQL but may be inefficient for
 778                         # some other DBMSes, mostly due to poor simulation by us
 779                         $dbw->replace(
 780                                 'watchlist',
 781                                 [ [ 'wl_user', 'wl_namespace', 'wl_title' ] ],
 782                                 $values,
 783                                 __METHOD__
 784                         );
 785                 }
 786
 787                 $this->reuseConnection( $dbw );
 788         }
 789
 790 }