includes/watcheditem/WatchedItemStore.php

   1 <?php
   2
   3 use Wikimedia\Rdbms\IDatabase;
   4 use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
   5 use MediaWiki\Linker\LinkTarget;
   6 use Wikimedia\Assert\Assert;
   7 use Wikimedia\ScopedCallback;
   8 use Wikimedia\Rdbms\ILBFactory;
   9 use Wikimedia\Rdbms\LoadBalancer;
  10
  11 /**
  12  * Storage layer class for WatchedItems.
  13  * Database interaction & caching
  14  * TODO caching should be factored out into a CachingWatchedItemStore class
  15  *
  16  * @author Addshore
  17  * @since 1.27
  18  */
  19 class WatchedItemStore implements WatchedItemStoreInterface, StatsdAwareInterface {
  20
  21         /**
  22          * @var ILBFactory
  23          */
  24         private $lbFactory;
  25
  26         /**
  27          * @var LoadBalancer
  28          */
  29         private $loadBalancer;
  30
  31         /**
  32          * @var JobQueueGroup
  33          */
  34         private $queueGroup;
  35
  36         /**
  37          * @var BagOStuff
  38          */
  39         private $stash;
  40
  41         /**
  42          * @var ReadOnlyMode
  43          */
  44         private $readOnlyMode;
  45
  46         /**
  47          * @var HashBagOStuff
  48          */
  49         private $cache;
  50
  51         /**
  52          * @var HashBagOStuff
  53          */
  54         private $latestUpdateCache;
  55
  56         /**
  57          * @var array[] Looks like $cacheIndex[Namespace ID][Target DB Key][User Id] => 'key'
  58          * The index is needed so that on mass changes all relevant items can be un-cached.
  59          * For example: Clearing a users watchlist of all items or updating notification timestamps
  60          *              for all users watching a single target.
  61          */
  62         private $cacheIndex = [];
  63
  64         /**
  65          * @var callable|null
  66          */
  67         private $deferredUpdatesAddCallableUpdateCallback;
  68
  69         /**
  70          * @var callable|null
  71          */
  72         private $revisionGetTimestampFromIdCallback;
  73
  74         /**
  75          * @var int
  76          */
  77         private $updateRowsPerQuery;
  78
  79         /**
  80          * @var StatsdDataFactoryInterface
  81          */
  82         private $stats;
  83
  84         /**
  85          * @param ILBFactory $lbFactory
  86          * @param JobQueueGroup $queueGroup
  87          * @param BagOStuff $stash
  88          * @param HashBagOStuff $cache
  89          * @param ReadOnlyMode $readOnlyMode
  90          * @param int $updateRowsPerQuery
  91          */
  92         public function __construct(
  93                 ILBFactory $lbFactory,
  94                 JobQueueGroup $queueGroup,
  95                 BagOStuff $stash,
  96                 HashBagOStuff $cache,
  97                 ReadOnlyMode $readOnlyMode,
  98                 $updateRowsPerQuery
  99         ) {
 100                 $this->lbFactory = $lbFactory;
 101                 $this->loadBalancer = $lbFactory->getMainLB();
 102                 $this->queueGroup = $queueGroup;
 103                 $this->stash = $stash;
 104                 $this->cache = $cache;
 105                 $this->readOnlyMode = $readOnlyMode;
 106                 $this->stats = new NullStatsdDataFactory();
 107                 $this->deferredUpdatesAddCallableUpdateCallback =
 108                         [ DeferredUpdates::class, 'addCallableUpdate' ];
 109                 $this->revisionGetTimestampFromIdCallback =
 110                         [ Revision::class, 'getTimestampFromId' ];
 111                 $this->updateRowsPerQuery = $updateRowsPerQuery;
 112
 113                 $this->latestUpdateCache = new HashBagOStuff( [ 'maxKeys' => 3 ] );
 114         }
 115
 116         /**
 117          * @param StatsdDataFactoryInterface $stats
 118          */
 119         public function setStatsdDataFactory( StatsdDataFactoryInterface $stats ) {
 120                 $this->stats = $stats;
 121         }
 122
 123         /**
 124          * Overrides the DeferredUpdates::addCallableUpdate callback
 125          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
 126          *
 127          * @param callable $callback
 128          *
 129          * @see DeferredUpdates::addCallableUpdate for callback signiture
 130          *
 131          * @return ScopedCallback to reset the overridden value
 132          * @throws MWException
 133          */
 134         public function overrideDeferredUpdatesAddCallableUpdateCallback( callable $callback ) {
 135                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 136                         throw new MWException(
 137                                 'Cannot override DeferredUpdates::addCallableUpdate callback in operation.'
 138                         );
 139                 }
 140                 $previousValue = $this->deferredUpdatesAddCallableUpdateCallback;
 141                 $this->deferredUpdatesAddCallableUpdateCallback = $callback;
 142                 return new ScopedCallback( function () use ( $previousValue ) {
 143                         $this->deferredUpdatesAddCallableUpdateCallback = $previousValue;
 144                 } );
 145         }
 146
 147         /**
 148          * Overrides the Revision::getTimestampFromId callback
 149          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
 150          *
 151          * @param callable $callback
 152          * @see Revision::getTimestampFromId for callback signiture
 153          *
 154          * @return ScopedCallback to reset the overridden value
 155          * @throws MWException
 156          */
 157         public function overrideRevisionGetTimestampFromIdCallback( callable $callback ) {
 158                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 159                         throw new MWException(
 160                                 'Cannot override Revision::getTimestampFromId callback in operation.'
 161                         );
 162                 }
 163                 $previousValue = $this->revisionGetTimestampFromIdCallback;
 164                 $this->revisionGetTimestampFromIdCallback = $callback;
 165                 return new ScopedCallback( function () use ( $previousValue ) {
 166                         $this->revisionGetTimestampFromIdCallback = $previousValue;
 167                 } );
 168         }
 169
 170         private function getCacheKey( User $user, LinkTarget $target ) {
 171                 return $this->cache->makeKey(
 172                         (string)$target->getNamespace(),
 173                         $target->getDBkey(),
 174                         (string)$user->getId()
 175                 );
 176         }
 177
 178         private function cache( WatchedItem $item ) {
 179                 $user = $item->getUser();
 180                 $target = $item->getLinkTarget();
 181                 $key = $this->getCacheKey( $user, $target );
 182                 $this->cache->set( $key, $item );
 183                 $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] = $key;
 184                 $this->stats->increment( 'WatchedItemStore.cache' );
 185         }
 186
 187         private function uncache( User $user, LinkTarget $target ) {
 188                 $this->cache->delete( $this->getCacheKey( $user, $target ) );
 189                 unset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] );
 190                 $this->stats->increment( 'WatchedItemStore.uncache' );
 191         }
 192
 193         private function uncacheLinkTarget( LinkTarget $target ) {
 194                 $this->stats->increment( 'WatchedItemStore.uncacheLinkTarget' );
 195                 if ( !isset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] ) ) {
 196                         return;
 197                 }
 198                 foreach ( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] as $key ) {
 199                         $this->stats->increment( 'WatchedItemStore.uncacheLinkTarget.items' );
 200                         $this->cache->delete( $key );
 201                 }
 202         }
 203
 204         private function uncacheUser( User $user ) {
 205                 $this->stats->increment( 'WatchedItemStore.uncacheUser' );
 206                 foreach ( $this->cacheIndex as $ns => $dbKeyArray ) {
 207                         foreach ( $dbKeyArray as $dbKey => $userArray ) {
 208                                 if ( isset( $userArray[$user->getId()] ) ) {
 209                                         $this->stats->increment( 'WatchedItemStore.uncacheUser.items' );
 210                                         $this->cache->delete( $userArray[$user->getId()] );
 211                                 }
 212                         }
 213                 }
 214
 215                 $pageSeenKey = $this->getPageSeenTimestampsKey( $user );
 216                 $this->latestUpdateCache->delete( $pageSeenKey );
 217                 $this->stash->delete( $pageSeenKey );
 218         }
 219
 220         /**
 221          * @param User $user
 222          * @param LinkTarget $target
 223          *
 224          * @return WatchedItem|false
 225          */
 226         private function getCached( User $user, LinkTarget $target ) {
 227                 return $this->cache->get( $this->getCacheKey( $user, $target ) );
 228         }
 229
 230         /**
 231          * Return an array of conditions to select or update the appropriate database
 232          * row.
 233          *
 234          * @param User $user
 235          * @param LinkTarget $target
 236          *
 237          * @return array
 238          */
 239         private function dbCond( User $user, LinkTarget $target ) {
 240                 return [
 241                         'wl_user' => $user->getId(),
 242                         'wl_namespace' => $target->getNamespace(),
 243                         'wl_title' => $target->getDBkey(),
 244                 ];
 245         }
 246
 247         /**
 248          * @param int $dbIndex DB_MASTER or DB_REPLICA
 249          *
 250          * @return IDatabase
 251          * @throws MWException
 252          */
 253         private function getConnectionRef( $dbIndex ) {
 254                 return $this->loadBalancer->getConnectionRef( $dbIndex, [ 'watchlist' ] );
 255         }
 256
 257         /**
 258          * Deletes ALL watched items for the given user when under
 259          * $updateRowsPerQuery entries exist.
 260          *
 261          * @since 1.30
 262          *
 263          * @param User $user
 264          *
 265          * @return bool true on success, false when too many items are watched
 266          */
 267         public function clearUserWatchedItems( User $user ) {
 268                 if ( $this->countWatchedItems( $user ) > $this->updateRowsPerQuery ) {
 269                         return false;
 270                 }
 271
 272                 $dbw = $this->loadBalancer->getConnectionRef( DB_MASTER );
 273                 $dbw->delete(
 274                         'watchlist',
 275                         [ 'wl_user' => $user->getId() ],
 276                         __METHOD__
 277                 );
 278                 $this->uncacheAllItemsForUser( $user );
 279
 280                 return true;
 281         }
 282
 283         private function uncacheAllItemsForUser( User $user ) {
 284                 $userId = $user->getId();
 285                 foreach ( $this->cacheIndex as $ns => $dbKeyIndex ) {
 286                         foreach ( $dbKeyIndex as $dbKey => $userIndex ) {
 287                                 if ( array_key_exists( $userId, $userIndex ) ) {
 288                                         $this->cache->delete( $userIndex[$userId] );
 289                                         unset( $this->cacheIndex[$ns][$dbKey][$userId] );
 290                                 }
 291                         }
 292                 }
 293
 294                 // Cleanup empty cache keys
 295                 foreach ( $this->cacheIndex as $ns => $dbKeyIndex ) {
 296                         foreach ( $dbKeyIndex as $dbKey => $userIndex ) {
 297                                 if ( empty( $this->cacheIndex[$ns][$dbKey] ) ) {
 298                                         unset( $this->cacheIndex[$ns][$dbKey] );
 299                                 }
 300                         }
 301                         if ( empty( $this->cacheIndex[$ns] ) ) {
 302                                 unset( $this->cacheIndex[$ns] );
 303                         }
 304                 }
 305         }
 306
 307         /**
 308          * Queues a job that will clear the users watchlist using the Job Queue.
 309          *
 310          * @since 1.31
 311          *
 312          * @param User $user
 313          */
 314         public function clearUserWatchedItemsUsingJobQueue( User $user ) {
 315                 $job = ClearUserWatchlistJob::newForUser( $user, $this->getMaxId() );
 316                 $this->queueGroup->push( $job );
 317         }
 318
 319         /**
 320          * @since 1.31
 321          * @return int The maximum current wl_id
 322          */
 323         public function getMaxId() {
 324                 $dbr = $this->getConnectionRef( DB_REPLICA );
 325                 return (int)$dbr->selectField(
 326                         'watchlist',
 327                         'MAX(wl_id)',
 328                         '',
 329                         __METHOD__
 330                 );
 331         }
 332
 333         /**
 334          * @since 1.31
 335          * @param User $user
 336          * @return int
 337          */
 338         public function countWatchedItems( User $user ) {
 339                 $dbr = $this->getConnectionRef( DB_REPLICA );
 340                 $return = (int)$dbr->selectField(
 341                         'watchlist',
 342                         'COUNT(*)',
 343                         [
 344                                 'wl_user' => $user->getId()
 345                         ],
 346                         __METHOD__
 347                 );
 348
 349                 return $return;
 350         }
 351
 352         /**
 353          * @since 1.27
 354          * @param LinkTarget $target
 355          * @return int
 356          */
 357         public function countWatchers( LinkTarget $target ) {
 358                 $dbr = $this->getConnectionRef( DB_REPLICA );
 359                 $return = (int)$dbr->selectField(
 360                         'watchlist',
 361                         'COUNT(*)',
 362                         [
 363                                 'wl_namespace' => $target->getNamespace(),
 364                                 'wl_title' => $target->getDBkey(),
 365                         ],
 366                         __METHOD__
 367                 );
 368
 369                 return $return;
 370         }
 371
 372         /**
 373          * @since 1.27
 374          * @param LinkTarget $target
 375          * @param string|int $threshold
 376          * @return int
 377          */
 378         public function countVisitingWatchers( LinkTarget $target, $threshold ) {
 379                 $dbr = $this->getConnectionRef( DB_REPLICA );
 380                 $visitingWatchers = (int)$dbr->selectField(
 381                         'watchlist',
 382                         'COUNT(*)',
 383                         [
 384                                 'wl_namespace' => $target->getNamespace(),
 385                                 'wl_title' => $target->getDBkey(),
 386                                 'wl_notificationtimestamp >= ' .
 387                                 $dbr->addQuotes( $dbr->timestamp( $threshold ) ) .
 388                                 ' OR wl_notificationtimestamp IS NULL'
 389                         ],
 390                         __METHOD__
 391                 );
 392
 393                 return $visitingWatchers;
 394         }
 395
 396         /**
 397          * @param User $user
 398          * @param TitleValue[] $titles
 399          * @return bool
 400          * @throws MWException
 401          */
 402         public function removeWatchBatchForUser( User $user, array $titles ) {
 403                 if ( $this->readOnlyMode->isReadOnly() ) {
 404                         return false;
 405                 }
 406                 if ( $user->isAnon() ) {
 407                         return false;
 408                 }
 409                 if ( !$titles ) {
 410                         return true;
 411                 }
 412
 413                 $rows = $this->getTitleDbKeysGroupedByNamespace( $titles );
 414                 $this->uncacheTitlesForUser( $user, $titles );
 415
 416                 $dbw = $this->getConnectionRef( DB_MASTER );
 417                 $ticket = count( $titles ) > $this->updateRowsPerQuery ?
 418                         $this->lbFactory->getEmptyTransactionTicket( __METHOD__ ) : null;
 419                 $affectedRows = 0;
 420
 421                 // Batch delete items per namespace.
 422                 foreach ( $rows as $namespace => $namespaceTitles ) {
 423                         $rowBatches = array_chunk( $namespaceTitles, $this->updateRowsPerQuery );
 424                         foreach ( $rowBatches as $toDelete ) {
 425                                 $dbw->delete( 'watchlist', [
 426                                         'wl_user' => $user->getId(),
 427                                         'wl_namespace' => $namespace,
 428                                         'wl_title' => $toDelete
 429                                 ], __METHOD__ );
 430                                 $affectedRows += $dbw->affectedRows();
 431                                 if ( $ticket ) {
 432                                         $this->lbFactory->commitAndWaitForReplication( __METHOD__, $ticket );
 433                                 }
 434                         }
 435                 }
 436
 437                 return (bool)$affectedRows;
 438         }
 439
 440         /**
 441          * @since 1.27
 442          * @param LinkTarget[] $targets
 443          * @param array $options
 444          * @return array
 445          */
 446         public function countWatchersMultiple( array $targets, array $options = [] ) {
 447                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 448
 449                 $dbr = $this->getConnectionRef( DB_REPLICA );
 450
 451                 if ( array_key_exists( 'minimumWatchers', $options ) ) {
 452                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$options['minimumWatchers'];
 453                 }
 454
 455                 $lb = new LinkBatch( $targets );
 456                 $res = $dbr->select(
 457                         'watchlist',
 458                         [ 'wl_title', 'wl_namespace', 'watchers' => 'COUNT(*)' ],
 459                         [ $lb->constructSet( 'wl', $dbr ) ],
 460                         __METHOD__,
 461                         $dbOptions
 462                 );
 463
 464                 $watchCounts = [];
 465                 foreach ( $targets as $linkTarget ) {
 466                         $watchCounts[$linkTarget->getNamespace()][$linkTarget->getDBkey()] = 0;
 467                 }
 468
 469                 foreach ( $res as $row ) {
 470                         $watchCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 471                 }
 472
 473                 return $watchCounts;
 474         }
 475
 476         /**
 477          * @since 1.27
 478          * @param array $targetsWithVisitThresholds
 479          * @param int|null $minimumWatchers
 480          * @return array
 481          */
 482         public function countVisitingWatchersMultiple(
 483                 array $targetsWithVisitThresholds,
 484                 $minimumWatchers = null
 485         ) {
 486                 if ( $targetsWithVisitThresholds === [] ) {
 487                         // No titles requested => no results returned
 488                         return [];
 489                 }
 490
 491                 $dbr = $this->getConnectionRef( DB_REPLICA );
 492
 493                 $conds = $this->getVisitingWatchersCondition( $dbr, $targetsWithVisitThresholds );
 494
 495                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 496                 if ( $minimumWatchers !== null ) {
 497                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$minimumWatchers;
 498                 }
 499                 $res = $dbr->select(
 500                         'watchlist',
 501                         [ 'wl_namespace', 'wl_title', 'watchers' => 'COUNT(*)' ],
 502                         $conds,
 503                         __METHOD__,
 504                         $dbOptions
 505                 );
 506
 507                 $watcherCounts = [];
 508                 foreach ( $targetsWithVisitThresholds as list( $target ) ) {
 509                         /* @var LinkTarget $target */
 510                         $watcherCounts[$target->getNamespace()][$target->getDBkey()] = 0;
 511                 }
 512
 513                 foreach ( $res as $row ) {
 514                         $watcherCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 515                 }
 516
 517                 return $watcherCounts;
 518         }
 519
 520         /**
 521          * Generates condition for the query used in a batch count visiting watchers.
 522          *
 523          * @param IDatabase $db
 524          * @param array $targetsWithVisitThresholds array of pairs (LinkTarget, last visit threshold)
 525          * @return string
 526          */
 527         private function getVisitingWatchersCondition(
 528                 IDatabase $db,
 529                 array $targetsWithVisitThresholds
 530         ) {
 531                 $missingTargets = [];
 532                 $namespaceConds = [];
 533                 foreach ( $targetsWithVisitThresholds as list( $target, $threshold ) ) {
 534                         if ( $threshold === null ) {
 535                                 $missingTargets[] = $target;
 536                                 continue;
 537                         }
 538                         /* @var LinkTarget $target */
 539                         $namespaceConds[$target->getNamespace()][] = $db->makeList( [
 540                                 'wl_title = ' . $db->addQuotes( $target->getDBkey() ),
 541                                 $db->makeList( [
 542                                         'wl_notificationtimestamp >= ' . $db->addQuotes( $db->timestamp( $threshold ) ),
 543                                         'wl_notificationtimestamp IS NULL'
 544                                 ], LIST_OR )
 545                         ], LIST_AND );
 546                 }
 547
 548                 $conds = [];
 549                 foreach ( $namespaceConds as $namespace => $pageConds ) {
 550                         $conds[] = $db->makeList( [
 551                                 'wl_namespace = ' . $namespace,
 552                                 '(' . $db->makeList( $pageConds, LIST_OR ) . ')'
 553                         ], LIST_AND );
 554                 }
 555
 556                 if ( $missingTargets ) {
 557                         $lb = new LinkBatch( $missingTargets );
 558                         $conds[] = $lb->constructSet( 'wl', $db );
 559                 }
 560
 561                 return $db->makeList( $conds, LIST_OR );
 562         }
 563
 564         /**
 565          * @since 1.27
 566          * @param User $user
 567          * @param LinkTarget $target
 568          * @return bool
 569          */
 570         public function getWatchedItem( User $user, LinkTarget $target ) {
 571                 if ( $user->isAnon() ) {
 572                         return false;
 573                 }
 574
 575                 $cached = $this->getCached( $user, $target );
 576                 if ( $cached ) {
 577                         $this->stats->increment( 'WatchedItemStore.getWatchedItem.cached' );
 578                         return $cached;
 579                 }
 580                 $this->stats->increment( 'WatchedItemStore.getWatchedItem.load' );
 581                 return $this->loadWatchedItem( $user, $target );
 582         }
 583
 584         /**
 585          * @since 1.27
 586          * @param User $user
 587          * @param LinkTarget $target
 588          * @return WatchedItem|bool
 589          */
 590         public function loadWatchedItem( User $user, LinkTarget $target ) {
 591                 // Only loggedin user can have a watchlist
 592                 if ( $user->isAnon() ) {
 593                         return false;
 594                 }
 595
 596                 $dbr = $this->getConnectionRef( DB_REPLICA );
 597
 598                 $row = $dbr->selectRow(
 599                         'watchlist',
 600                         'wl_notificationtimestamp',
 601                         $this->dbCond( $user, $target ),
 602                         __METHOD__
 603                 );
 604
 605                 if ( !$row ) {
 606                         return false;
 607                 }
 608
 609                 $item = new WatchedItem(
 610                         $user,
 611                         $target,
 612                         $this->getLatestNotificationTimestamp( $row->wl_notificationtimestamp, $user, $target )
 613                 );
 614                 $this->cache( $item );
 615
 616                 return $item;
 617         }
 618
 619         /**
 620          * @since 1.27
 621          * @param User $user
 622          * @param array $options
 623          * @return WatchedItem[]
 624          */
 625         public function getWatchedItemsForUser( User $user, array $options = [] ) {
 626                 $options += [ 'forWrite' => false ];
 627
 628                 $dbOptions = [];
 629                 if ( array_key_exists( 'sort', $options ) ) {
 630                         Assert::parameter(
 631                                 ( in_array( $options['sort'], [ self::SORT_ASC, self::SORT_DESC ] ) ),
 632                                 '$options[\'sort\']',
 633                                 'must be SORT_ASC or SORT_DESC'
 634                         );
 635                         $dbOptions['ORDER BY'] = [
 636                                 "wl_namespace {$options['sort']}",
 637                                 "wl_title {$options['sort']}"
 638                         ];
 639                 }
 640                 $db = $this->getConnectionRef( $options['forWrite'] ? DB_MASTER : DB_REPLICA );
 641
 642                 $res = $db->select(
 643                         'watchlist',
 644                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 645                         [ 'wl_user' => $user->getId() ],
 646                         __METHOD__,
 647                         $dbOptions
 648                 );
 649
 650                 $watchedItems = [];
 651                 foreach ( $res as $row ) {
 652                         $target = new TitleValue( (int)$row->wl_namespace, $row->wl_title );
 653                         // @todo: Should we add these to the process cache?
 654                         $watchedItems[] = new WatchedItem(
 655                                 $user,
 656                                 new TitleValue( (int)$row->wl_namespace, $row->wl_title ),
 657                                 $this->getLatestNotificationTimestamp(
 658                                         $row->wl_notificationtimestamp, $user, $target )
 659                         );
 660                 }
 661
 662                 return $watchedItems;
 663         }
 664
 665         /**
 666          * @since 1.27
 667          * @param User $user
 668          * @param LinkTarget $target
 669          * @return bool
 670          */
 671         public function isWatched( User $user, LinkTarget $target ) {
 672                 return (bool)$this->getWatchedItem( $user, $target );
 673         }
 674
 675         /**
 676          * @since 1.27
 677          * @param User $user
 678          * @param LinkTarget[] $targets
 679          * @return array
 680          */
 681         public function getNotificationTimestampsBatch( User $user, array $targets ) {
 682                 $timestamps = [];
 683                 foreach ( $targets as $target ) {
 684                         $timestamps[$target->getNamespace()][$target->getDBkey()] = false;
 685                 }
 686
 687                 if ( $user->isAnon() ) {
 688                         return $timestamps;
 689                 }
 690
 691                 $targetsToLoad = [];
 692                 foreach ( $targets as $target ) {
 693                         $cachedItem = $this->getCached( $user, $target );
 694                         if ( $cachedItem ) {
 695                                 $timestamps[$target->getNamespace()][$target->getDBkey()] =
 696                                         $cachedItem->getNotificationTimestamp();
 697                         } else {
 698                                 $targetsToLoad[] = $target;
 699                         }
 700                 }
 701
 702                 if ( !$targetsToLoad ) {
 703                         return $timestamps;
 704                 }
 705
 706                 $dbr = $this->getConnectionRef( DB_REPLICA );
 707
 708                 $lb = new LinkBatch( $targetsToLoad );
 709                 $res = $dbr->select(
 710                         'watchlist',
 711                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 712                         [
 713                                 $lb->constructSet( 'wl', $dbr ),
 714                                 'wl_user' => $user->getId(),
 715                         ],
 716                         __METHOD__
 717                 );
 718
 719                 foreach ( $res as $row ) {
 720                         $target = new TitleValue( (int)$row->wl_namespace, $row->wl_title );
 721                         $timestamps[$row->wl_namespace][$row->wl_title] =
 722                                 $this->getLatestNotificationTimestamp(
 723                                         $row->wl_notificationtimestamp, $user, $target );
 724                 }
 725
 726                 return $timestamps;
 727         }
 728
 729         /**
 730          * @since 1.27
 731          * @param User $user
 732          * @param LinkTarget $target
 733          * @throws MWException
 734          */
 735         public function addWatch( User $user, LinkTarget $target ) {
 736                 $this->addWatchBatchForUser( $user, [ $target ] );
 737         }
 738
 739         /**
 740          * @since 1.27
 741          * @param User $user
 742          * @param LinkTarget[] $targets
 743          * @return bool
 744          * @throws MWException
 745          */
 746         public function addWatchBatchForUser( User $user, array $targets ) {
 747                 if ( $this->readOnlyMode->isReadOnly() ) {
 748                         return false;
 749                 }
 750                 // Only logged-in user can have a watchlist
 751                 if ( $user->isAnon() ) {
 752                         return false;
 753                 }
 754
 755                 if ( !$targets ) {
 756                         return true;
 757                 }
 758
 759                 $rows = [];
 760                 $items = [];
 761                 foreach ( $targets as $target ) {
 762                         $rows[] = [
 763                                 'wl_user' => $user->getId(),
 764                                 'wl_namespace' => $target->getNamespace(),
 765                                 'wl_title' => $target->getDBkey(),
 766                                 'wl_notificationtimestamp' => null,
 767                         ];
 768                         $items[] = new WatchedItem(
 769                                 $user,
 770                                 $target,
 771                                 null
 772                         );
 773                         $this->uncache( $user, $target );
 774                 }
 775
 776                 $dbw = $this->getConnectionRef( DB_MASTER );
 777                 $ticket = count( $targets ) > $this->updateRowsPerQuery ?
 778                         $this->lbFactory->getEmptyTransactionTicket( __METHOD__ ) : null;
 779                 $affectedRows = 0;
 780                 $rowBatches = array_chunk( $rows, $this->updateRowsPerQuery );
 781                 foreach ( $rowBatches as $toInsert ) {
 782                         // Use INSERT IGNORE to avoid overwriting the notification timestamp
 783                         // if there's already an entry for this page
 784                         $dbw->insert( 'watchlist', $toInsert, __METHOD__, 'IGNORE' );
 785                         $affectedRows += $dbw->affectedRows();
 786                         if ( $ticket ) {
 787                                 $this->lbFactory->commitAndWaitForReplication( __METHOD__, $ticket );
 788                         }
 789                 }
 790                 // Update process cache to ensure skin doesn't claim that the current
 791                 // page is unwatched in the response of action=watch itself (T28292).
 792                 // This would otherwise be re-queried from a replica by isWatched().
 793                 foreach ( $items as $item ) {
 794                         $this->cache( $item );
 795                 }
 796
 797                 return (bool)$affectedRows;
 798         }
 799
 800         /**
 801          * @since 1.27
 802          * @param User $user
 803          * @param LinkTarget $target
 804          * @return bool
 805          * @throws MWException
 806          */
 807         public function removeWatch( User $user, LinkTarget $target ) {
 808                 return $this->removeWatchBatchForUser( $user, [ $target ] );
 809         }
 810
 811         /**
 812          * Set the "last viewed" timestamps for certain titles on a user's watchlist.
 813          *
 814          * If the $targets parameter is omitted or set to [], this method simply wraps
 815          * resetAllNotificationTimestampsForUser(), and in that case you should instead call that method
 816          * directly; support for omitting $targets is for backwards compatibility.
 817          *
 818          * If $targets is omitted or set to [], timestamps will be updated for every title on the user's
 819          * watchlist, and this will be done through a DeferredUpdate. If $targets is a non-empty array,
 820          * only the specified titles will be updated, and this will be done immediately (not deferred).
 821          *
 822          * @since 1.27
 823          * @param User $user
 824          * @param string|int $timestamp Value to set the "last viewed" timestamp to (null to clear)
 825          * @param LinkTarget[] $targets Titles to set the timestamp for; [] means the entire watchlist
 826          * @return bool
 827          */
 828         public function setNotificationTimestampsForUser( User $user, $timestamp, array $targets = [] ) {
 829                 // Only loggedin user can have a watchlist
 830                 if ( $user->isAnon() || $this->readOnlyMode->isReadOnly() ) {
 831                         return false;
 832                 }
 833
 834                 if ( !$targets ) {
 835                         // Backwards compatibility
 836                         $this->resetAllNotificationTimestampsForUser( $user, $timestamp );
 837                         return true;
 838                 }
 839
 840                 $rows = $this->getTitleDbKeysGroupedByNamespace( $targets );
 841
 842                 $dbw = $this->getConnectionRef( DB_MASTER );
 843                 if ( $timestamp !== null ) {
 844                         $timestamp = $dbw->timestamp( $timestamp );
 845                 }
 846                 $ticket = $this->lbFactory->getEmptyTransactionTicket( __METHOD__ );
 847                 $affectedSinceWait = 0;
 848
 849                 // Batch update items per namespace
 850                 foreach ( $rows as $namespace => $namespaceTitles ) {
 851                         $rowBatches = array_chunk( $namespaceTitles, $this->updateRowsPerQuery );
 852                         foreach ( $rowBatches as $toUpdate ) {
 853                                 $dbw->update(
 854                                         'watchlist',
 855                                         [ 'wl_notificationtimestamp' => $timestamp ],
 856                                         [
 857                                                 'wl_user' => $user->getId(),
 858                                                 'wl_namespace' => $namespace,
 859                                                 'wl_title' => $toUpdate
 860                                         ]
 861                                 );
 862                                 $affectedSinceWait += $dbw->affectedRows();
 863                                 // Wait for replication every time we've touched updateRowsPerQuery rows
 864                                 if ( $affectedSinceWait >= $this->updateRowsPerQuery ) {
 865                                         $this->lbFactory->commitAndWaitForReplication( __METHOD__, $ticket );
 866                                         $affectedSinceWait = 0;
 867                                 }
 868                         }
 869                 }
 870
 871                 $this->uncacheUser( $user );
 872
 873                 return true;
 874         }
 875
 876         public function getLatestNotificationTimestamp( $timestamp, User $user, LinkTarget $target ) {
 877                 $timestamp = wfTimestampOrNull( TS_MW, $timestamp );
 878                 if ( $timestamp === null ) {
 879                         return null; // no notification
 880                 }
 881
 882                 $seenTimestamps = $this->getPageSeenTimestamps( $user );
 883                 if (
 884                         $seenTimestamps &&
 885                         $seenTimestamps->get( $this->getPageSeenKey( $target ) ) >= $timestamp
 886                 ) {
 887                         // If a reset job did not yet run, then the "seen" timestamp will be higher
 888                         return null;
 889                 }
 890
 891                 return $timestamp;
 892         }
 893
 894         /**
 895          * Schedule a DeferredUpdate that sets all of the "last viewed" timestamps for a given user
 896          * to the same value.
 897          * @param User $user
 898          * @param string|int|null $timestamp Value to set all timestamps to, null to clear them
 899          */
 900         public function resetAllNotificationTimestampsForUser( User $user, $timestamp = null ) {
 901                 // Only loggedin user can have a watchlist
 902                 if ( $user->isAnon() ) {
 903                         return;
 904                 }
 905
 906                 // If the page is watched by the user (or may be watched), update the timestamp
 907                 $job = new ClearWatchlistNotificationsJob( [
 908                         'userId'  => $user->getId(), 'timestamp' => $timestamp, 'casTime' => time()
 909                 ] );
 910
 911                 // Try to run this post-send
 912                 // Calls DeferredUpdates::addCallableUpdate in normal operation
 913                 call_user_func(
 914                         $this->deferredUpdatesAddCallableUpdateCallback,
 915                         function () use ( $job ) {
 916                                 $job->run();
 917                         }
 918                 );
 919         }
 920
 921         /**
 922          * @since 1.27
 923          * @param User $editor
 924          * @param LinkTarget $target
 925          * @param string|int $timestamp
 926          * @return int[]
 927          */
 928         public function updateNotificationTimestamp( User $editor, LinkTarget $target, $timestamp ) {
 929                 $dbw = $this->getConnectionRef( DB_MASTER );
 930                 $uids = $dbw->selectFieldValues(
 931                         'watchlist',
 932                         'wl_user',
 933                         [
 934                                 'wl_user != ' . intval( $editor->getId() ),
 935                                 'wl_namespace' => $target->getNamespace(),
 936                                 'wl_title' => $target->getDBkey(),
 937                                 'wl_notificationtimestamp IS NULL',
 938                         ],
 939                         __METHOD__
 940                 );
 941
 942                 $watchers = array_map( 'intval', $uids );
 943                 if ( $watchers ) {
 944                         // Update wl_notificationtimestamp for all watching users except the editor
 945                         $fname = __METHOD__;
 946                         DeferredUpdates::addCallableUpdate(
 947                                 function () use ( $timestamp, $watchers, $target, $fname ) {
 948                                         $dbw = $this->getConnectionRef( DB_MASTER );
 949                                         $ticket = $this->lbFactory->getEmptyTransactionTicket( $fname );
 950
 951                                         $watchersChunks = array_chunk( $watchers, $this->updateRowsPerQuery );
 952                                         foreach ( $watchersChunks as $watchersChunk ) {
 953                                                 $dbw->update( 'watchlist',
 954                                                         [ /* SET */
 955                                                                 'wl_notificationtimestamp' => $dbw->timestamp( $timestamp )
 956                                                         ], [ /* WHERE - TODO Use wl_id T130067 */
 957                                                                 'wl_user' => $watchersChunk,
 958                                                                 'wl_namespace' => $target->getNamespace(),
 959                                                                 'wl_title' => $target->getDBkey(),
 960                                                         ], $fname
 961                                                 );
 962                                                 if ( count( $watchersChunks ) > 1 ) {
 963                                                         $this->lbFactory->commitAndWaitForReplication(
 964                                                                 $fname, $ticket, [ 'domain' => $dbw->getDomainID() ]
 965                                                         );
 966                                                 }
 967                                         }
 968                                         $this->uncacheLinkTarget( $target );
 969                                 },
 970                                 DeferredUpdates::POSTSEND,
 971                                 $dbw
 972                         );
 973                 }
 974
 975                 return $watchers;
 976         }
 977
 978         /**
 979          * @since 1.27
 980          * @param User $user
 981          * @param Title $title
 982          * @param string $force
 983          * @param int $oldid
 984          * @return bool
 985          */
 986         public function resetNotificationTimestamp( User $user, Title $title, $force = '', $oldid = 0 ) {
 987                 $time = time();
 988
 989                 // Only loggedin user can have a watchlist
 990                 if ( $this->readOnlyMode->isReadOnly() || $user->isAnon() ) {
 991                         return false;
 992                 }
 993
 994                 if ( !Hooks::run( 'BeforeResetNotificationTimestamp', [ &$user, &$title, $force, &$oldid ] ) ) {
 995                         return false;
 996                 }
 997
 998                 $item = null;
 999                 if ( $force != 'force' ) {
1000                         $item = $this->loadWatchedItem( $user, $title );
1001                         if ( !$item || $item->getNotificationTimestamp() === null ) {
1002                                 return false;
1003                         }
1004                 }
1005
1006                 // Get the timestamp (TS_MW) of this revision to track the latest one seen
1007                 $seenTime = call_user_func(
1008                         $this->revisionGetTimestampFromIdCallback,
1009                         $title,
1010                         $oldid ?: $title->getLatestRevID()
1011                 );
1012
1013                 // Mark the item as read immediately in lightweight storage
1014                 $this->stash->merge(
1015                         $this->getPageSeenTimestampsKey( $user ),
1016                         function ( $cache, $key, $current ) use ( $title, $seenTime ) {
1017                                 $value = $current ?: new MapCacheLRU( 300 );
1018                                 $subKey = $this->getPageSeenKey( $title );
1019
1020                                 if ( $seenTime > $value->get( $subKey ) ) {
1021                                         // Revision is newer than the last one seen
1022                                         $value->set( $subKey, $seenTime );
1023                                         $this->latestUpdateCache->set( $key, $value, IExpiringStore::TTL_PROC_LONG );
1024                                 } elseif ( $seenTime === false ) {
1025                                         // Revision does not exist
1026                                         $value->set( $subKey, wfTimestamp( TS_MW ) );
1027                                         $this->latestUpdateCache->set( $key, $value, IExpiringStore::TTL_PROC_LONG );
1028                                 } else {
1029                                         return false; // nothing to update
1030                                 }
1031
1032                                 return $value;
1033                         },
1034                         IExpiringStore::TTL_HOUR
1035                 );
1036
1037                 // If the page is watched by the user (or may be watched), update the timestamp
1038                 $job = new ActivityUpdateJob(
1039                         $title,
1040                         [
1041                                 'type'      => 'updateWatchlistNotification',
1042                                 'userid'    => $user->getId(),
1043                                 'notifTime' => $this->getNotificationTimestamp( $user, $title, $item, $force, $oldid ),
1044                                 'curTime'   => $time
1045                         ]
1046                 );
1047                 // Try to enqueue this post-send
1048                 $this->queueGroup->lazyPush( $job );
1049
1050                 $this->uncache( $user, $title );
1051
1052                 return true;
1053         }
1054
1055         /**
1056          * @param User $user
1057          * @return MapCacheLRU|null The map contains prefixed title keys and TS_MW values
1058          */
1059         private function getPageSeenTimestamps( User $user ) {
1060                 $key = $this->getPageSeenTimestampsKey( $user );
1061
1062                 return $this->latestUpdateCache->getWithSetCallback(
1063                         $key,
1064                         IExpiringStore::TTL_PROC_LONG,
1065                         function () use ( $key ) {
1066                                 return $this->stash->get( $key ) ?: null;
1067                         }
1068                 );
1069         }
1070
1071         /**
1072          * @param User $user
1073          * @return string
1074          */
1075         private function getPageSeenTimestampsKey( User $user ) {
1076                 return $this->stash->makeGlobalKey(
1077                         'watchlist-recent-updates',
1078                         $this->lbFactory->getLocalDomainID(),
1079                         $user->getId()
1080                 );
1081         }
1082
1083         /**
1084          * @param LinkTarget $target
1085          * @return string
1086          */
1087         private function getPageSeenKey( LinkTarget $target ) {
1088                 return "{$target->getNamespace()}:{$target->getDBkey()}";
1089         }
1090
1091         private function getNotificationTimestamp( User $user, Title $title, $item, $force, $oldid ) {
1092                 if ( !$oldid ) {
1093                         // No oldid given, assuming latest revision; clear the timestamp.
1094                         return null;
1095                 }
1096
1097                 if ( !$title->getNextRevisionID( $oldid ) ) {
1098                         // Oldid given and is the latest revision for this title; clear the timestamp.
1099                         return null;
1100                 }
1101
1102                 if ( $item === null ) {
1103                         $item = $this->loadWatchedItem( $user, $title );
1104                 }
1105
1106                 if ( !$item ) {
1107                         // This can only happen if $force is enabled.
1108                         return null;
1109                 }
1110
1111                 // Oldid given and isn't the latest; update the timestamp.
1112                 // This will result in no further notification emails being sent!
1113                 // Calls Revision::getTimestampFromId in normal operation
1114                 $notificationTimestamp = call_user_func(
1115                         $this->revisionGetTimestampFromIdCallback,
1116                         $title,
1117                         $oldid
1118                 );
1119
1120                 // We need to go one second to the future because of various strict comparisons
1121                 // throughout the codebase
1122                 $ts = new MWTimestamp( $notificationTimestamp );
1123                 $ts->timestamp->add( new DateInterval( 'PT1S' ) );
1124                 $notificationTimestamp = $ts->getTimestamp( TS_MW );
1125
1126                 if ( $notificationTimestamp < $item->getNotificationTimestamp() ) {
1127                         if ( $force != 'force' ) {
1128                                 return false;
1129                         } else {
1130                                 // This is a little silly…
1131                                 return $item->getNotificationTimestamp();
1132                         }
1133                 }
1134
1135                 return $notificationTimestamp;
1136         }
1137
1138         /**
1139          * @since 1.27
1140          * @param User $user
1141          * @param int|null $unreadLimit
1142          * @return int|bool
1143          */
1144         public function countUnreadNotifications( User $user, $unreadLimit = null ) {
1145                 $dbr = $this->getConnectionRef( DB_REPLICA );
1146
1147                 $queryOptions = [];
1148                 if ( $unreadLimit !== null ) {
1149                         $unreadLimit = (int)$unreadLimit;
1150                         $queryOptions['LIMIT'] = $unreadLimit;
1151                 }
1152
1153                 $conds = [
1154                         'wl_user' => $user->getId(),
1155                         'wl_notificationtimestamp IS NOT NULL'
1156                 ];
1157
1158                 $rowCount = $dbr->selectRowCount( 'watchlist', '1', $conds, __METHOD__, $queryOptions );
1159
1160                 if ( $unreadLimit === null ) {
1161                         return $rowCount;
1162                 }
1163
1164                 if ( $rowCount >= $unreadLimit ) {
1165                         return true;
1166                 }
1167
1168                 return $rowCount;
1169         }
1170
1171         /**
1172          * @since 1.27
1173          * @param LinkTarget $oldTarget
1174          * @param LinkTarget $newTarget
1175          */
1176         public function duplicateAllAssociatedEntries( LinkTarget $oldTarget, LinkTarget $newTarget ) {
1177                 $oldTarget = Title::newFromLinkTarget( $oldTarget );
1178                 $newTarget = Title::newFromLinkTarget( $newTarget );
1179
1180                 $this->duplicateEntry( $oldTarget->getSubjectPage(), $newTarget->getSubjectPage() );
1181                 $this->duplicateEntry( $oldTarget->getTalkPage(), $newTarget->getTalkPage() );
1182         }
1183
1184         /**
1185          * @since 1.27
1186          * @param LinkTarget $oldTarget
1187          * @param LinkTarget $newTarget
1188          */
1189         public function duplicateEntry( LinkTarget $oldTarget, LinkTarget $newTarget ) {
1190                 $dbw = $this->getConnectionRef( DB_MASTER );
1191
1192                 $result = $dbw->select(
1193                         'watchlist',
1194                         [ 'wl_user', 'wl_notificationtimestamp' ],
1195                         [
1196                                 'wl_namespace' => $oldTarget->getNamespace(),
1197                                 'wl_title' => $oldTarget->getDBkey(),
1198                         ],
1199                         __METHOD__,
1200                         [ 'FOR UPDATE' ]
1201                 );
1202
1203                 $newNamespace = $newTarget->getNamespace();
1204                 $newDBkey = $newTarget->getDBkey();
1205
1206                 # Construct array to replace into the watchlist
1207                 $values = [];
1208                 foreach ( $result as $row ) {
1209                         $values[] = [
1210                                 'wl_user' => $row->wl_user,
1211                                 'wl_namespace' => $newNamespace,
1212                                 'wl_title' => $newDBkey,
1213                                 'wl_notificationtimestamp' => $row->wl_notificationtimestamp,
1214                         ];
1215                 }
1216
1217                 if ( !empty( $values ) ) {
1218                         # Perform replace
1219                         # Note that multi-row replace is very efficient for MySQL but may be inefficient for
1220                         # some other DBMSes, mostly due to poor simulation by us
1221                         $dbw->replace(
1222                                 'watchlist',
1223                                 [ [ 'wl_user', 'wl_namespace', 'wl_title' ] ],
1224                                 $values,
1225                                 __METHOD__
1226                         );
1227                 }
1228         }
1229
1230         /**
1231          * @param LinkTarget[] $titles
1232          * @return array
1233          */
1234         private function getTitleDbKeysGroupedByNamespace( array $titles ) {
1235                 $rows = [];
1236                 foreach ( $titles as $title ) {
1237                         // Group titles by namespace.
1238                         $rows[ $title->getNamespace() ][] = $title->getDBkey();
1239                 }
1240                 return $rows;
1241         }
1242
1243         /**
1244          * @param User $user
1245          * @param Title[] $titles
1246          */
1247         private function uncacheTitlesForUser( User $user, array $titles ) {
1248                 foreach ( $titles as $title ) {
1249                         $this->uncache( $user, $title );
1250                 }
1251         }
1252
1253 }