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         const SORT_DESC = 'DESC';
  16         const SORT_ASC = 'ASC';
  17
  18         /**
  19          * @var LoadBalancer
  20          */
  21         private $loadBalancer;
  22
  23         /**
  24          * @var HashBagOStuff
  25          */
  26         private $cache;
  27
  28         /**
  29          * @var array[] Looks like $cacheIndex[Namespace ID][Target DB Key][User Id] => 'key'
  30          * The index is needed so that on mass changes all relevant items can be un-cached.
  31          * For example: Clearing a users watchlist of all items or updating notification timestamps
  32          *              for all users watching a single target.
  33          */
  34         private $cacheIndex = [];
  35
  36         /**
  37          * @var callable|null
  38          */
  39         private $deferredUpdatesAddCallableUpdateCallback;
  40
  41         /**
  42          * @var callable|null
  43          */
  44         private $revisionGetTimestampFromIdCallback;
  45
  46         /**
  47          * @var self|null
  48          */
  49         private static $instance;
  50
  51         /**
  52          * @param LoadBalancer $loadBalancer
  53          * @param HashBagOStuff $cache
  54          */
  55         public function __construct(
  56                 LoadBalancer $loadBalancer,
  57                 HashBagOStuff $cache
  58         ) {
  59                 $this->loadBalancer = $loadBalancer;
  60                 $this->cache = $cache;
  61                 $this->deferredUpdatesAddCallableUpdateCallback = [ 'DeferredUpdates', 'addCallableUpdate' ];
  62                 $this->revisionGetTimestampFromIdCallback = [ 'Revision', 'getTimestampFromId' ];
  63         }
  64
  65         /**
  66          * Overrides the DeferredUpdates::addCallableUpdate callback
  67          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
  68          *
  69          * @param callable $callback
  70          *
  71          * @see DeferredUpdates::addCallableUpdate for callback signiture
  72          *
  73          * @return ScopedCallback to reset the overridden value
  74          * @throws MWException
  75          */
  76         public function overrideDeferredUpdatesAddCallableUpdateCallback( $callback ) {
  77                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
  78                         throw new MWException(
  79                                 'Cannot override DeferredUpdates::addCallableUpdate callback in operation.'
  80                         );
  81                 }
  82                 Assert::parameterType( 'callable', $callback, '$callback' );
  83
  84                 $previousValue = $this->deferredUpdatesAddCallableUpdateCallback;
  85                 $this->deferredUpdatesAddCallableUpdateCallback = $callback;
  86                 return new ScopedCallback( function() use ( $previousValue ) {
  87                         $this->deferredUpdatesAddCallableUpdateCallback = $previousValue;
  88                 } );
  89         }
  90
  91         /**
  92          * Overrides the Revision::getTimestampFromId callback
  93          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
  94          *
  95          * @param callable $callback
  96          * @see Revision::getTimestampFromId for callback signiture
  97          *
  98          * @return ScopedCallback to reset the overridden value
  99          * @throws MWException
 100          */
 101         public function overrideRevisionGetTimestampFromIdCallback( $callback ) {
 102                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 103                         throw new MWException(
 104                                 'Cannot override Revision::getTimestampFromId callback in operation.'
 105                         );
 106                 }
 107                 Assert::parameterType( 'callable', $callback, '$callback' );
 108
 109                 $previousValue = $this->revisionGetTimestampFromIdCallback;
 110                 $this->revisionGetTimestampFromIdCallback = $callback;
 111                 return new ScopedCallback( function() use ( $previousValue ) {
 112                         $this->revisionGetTimestampFromIdCallback = $previousValue;
 113                 } );
 114         }
 115
 116         /**
 117          * Overrides the default instance of this class
 118          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
 119          *
 120          * If this method is used it MUST also be called with null after a test to ensure a new
 121          * default instance is created next time getDefaultInstance is called.
 122          *
 123          * @param WatchedItemStore|null $store
 124          *
 125          * @return ScopedCallback to reset the overridden value
 126          * @throws MWException
 127          */
 128         public static function overrideDefaultInstance( WatchedItemStore $store = null ) {
 129                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 130                         throw new MWException(
 131                                 'Cannot override ' . __CLASS__ . 'default instance in operation.'
 132                         );
 133                 }
 134
 135                 $previousValue = self::$instance;
 136                 self::$instance = $store;
 137                 return new ScopedCallback( function() use ( $previousValue ) {
 138                         self::$instance = $previousValue;
 139                 } );
 140         }
 141
 142         /**
 143          * @return self
 144          */
 145         public static function getDefaultInstance() {
 146                 if ( !self::$instance ) {
 147                         self::$instance = new self(
 148                                 wfGetLB(),
 149                                 new HashBagOStuff( [ 'maxKeys' => 100 ] )
 150                         );
 151                 }
 152                 return self::$instance;
 153         }
 154
 155         private function getCacheKey( User $user, LinkTarget $target ) {
 156                 return $this->cache->makeKey(
 157                         (string)$target->getNamespace(),
 158                         $target->getDBkey(),
 159                         (string)$user->getId()
 160                 );
 161         }
 162
 163         private function cache( WatchedItem $item ) {
 164                 $user = $item->getUser();
 165                 $target = $item->getLinkTarget();
 166                 $key = $this->getCacheKey( $user, $target );
 167                 $this->cache->set( $key, $item );
 168                 $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] = $key;
 169         }
 170
 171         private function uncache( User $user, LinkTarget $target ) {
 172                 $this->cache->delete( $this->getCacheKey( $user, $target ) );
 173                 unset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] );
 174         }
 175
 176         private function uncacheLinkTarget( LinkTarget $target ) {
 177                 if ( !isset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] ) ) {
 178                         return;
 179                 }
 180                 foreach ( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] as $key ) {
 181                         $this->cache->delete( $key );
 182                 }
 183         }
 184
 185         /**
 186          * @param User $user
 187          * @param LinkTarget $target
 188          *
 189          * @return WatchedItem|null
 190          */
 191         private function getCached( User $user, LinkTarget $target ) {
 192                 return $this->cache->get( $this->getCacheKey( $user, $target ) );
 193         }
 194
 195         /**
 196          * Return an array of conditions to select or update the appropriate database
 197          * row.
 198          *
 199          * @param User $user
 200          * @param LinkTarget $target
 201          *
 202          * @return array
 203          */
 204         private function dbCond( User $user, LinkTarget $target ) {
 205                 return [
 206                         'wl_user' => $user->getId(),
 207                         'wl_namespace' => $target->getNamespace(),
 208                         'wl_title' => $target->getDBkey(),
 209                 ];
 210         }
 211
 212         /**
 213          * @param int $slaveOrMaster DB_MASTER or DB_SLAVE
 214          *
 215          * @return DatabaseBase
 216          * @throws MWException
 217          */
 218         private function getConnection( $slaveOrMaster ) {
 219                 return $this->loadBalancer->getConnection( $slaveOrMaster, [ 'watchlist' ] );
 220         }
 221
 222         /**
 223          * @param DatabaseBase $connection
 224          *
 225          * @throws MWException
 226          */
 227         private function reuseConnection( $connection ) {
 228                 $this->loadBalancer->reuseConnection( $connection );
 229         }
 230
 231         /**
 232          * Count the number of individual items that are watched by the user.
 233          * If a subject and corresponding talk page are watched this will return 2.
 234          *
 235          * @param User $user
 236          *
 237          * @return int
 238          */
 239         public function countWatchedItems( User $user ) {
 240                 $dbr = $this->getConnection( DB_SLAVE );
 241                 $return = (int)$dbr->selectField(
 242                         'watchlist',
 243                         'COUNT(*)',
 244                         [
 245                                 'wl_user' => $user->getId()
 246                         ],
 247                         __METHOD__
 248                 );
 249                 $this->reuseConnection( $dbr );
 250
 251                 return $return;
 252         }
 253
 254         /**
 255          * @param LinkTarget $target
 256          *
 257          * @return int
 258          */
 259         public function countWatchers( LinkTarget $target ) {
 260                 $dbr = $this->getConnection( DB_SLAVE );
 261                 $return = (int)$dbr->selectField(
 262                         'watchlist',
 263                         'COUNT(*)',
 264                         [
 265                                 'wl_namespace' => $target->getNamespace(),
 266                                 'wl_title' => $target->getDBkey(),
 267                         ],
 268                         __METHOD__
 269                 );
 270                 $this->reuseConnection( $dbr );
 271
 272                 return $return;
 273         }
 274
 275         /**
 276          * Number of page watchers who also visited a "recent" edit
 277          *
 278          * @param LinkTarget $target
 279          * @param mixed $threshold timestamp accepted by wfTimestamp
 280          *
 281          * @return int
 282          * @throws DBUnexpectedError
 283          * @throws MWException
 284          */
 285         public function countVisitingWatchers( LinkTarget $target, $threshold ) {
 286                 $dbr = $this->getConnection( DB_SLAVE );
 287                 $visitingWatchers = (int)$dbr->selectField(
 288                         'watchlist',
 289                         'COUNT(*)',
 290                         [
 291                                 'wl_namespace' => $target->getNamespace(),
 292                                 'wl_title' => $target->getDBkey(),
 293                                 'wl_notificationtimestamp >= ' .
 294                                 $dbr->addQuotes( $dbr->timestamp( $threshold ) ) .
 295                                 ' OR wl_notificationtimestamp IS NULL'
 296                         ],
 297                         __METHOD__
 298                 );
 299                 $this->reuseConnection( $dbr );
 300
 301                 return $visitingWatchers;
 302         }
 303
 304         /**
 305          * @param LinkTarget[] $targets
 306          * @param array $options Allowed keys:
 307          *        'minimumWatchers' => int
 308          *
 309          * @return array multi dimensional like $return[$namespaceId][$titleString] = int $watchers
 310          *         All targets will be present in the result. 0 either means no watchers or the number
 311          *         of watchers was below the minimumWatchers option if passed.
 312          */
 313         public function countWatchersMultiple( array $targets, array $options = [] ) {
 314                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 315
 316                 $dbr = $this->getConnection( DB_SLAVE );
 317
 318                 if ( array_key_exists( 'minimumWatchers', $options ) ) {
 319                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$options['minimumWatchers'];
 320                 }
 321
 322                 $lb = new LinkBatch( $targets );
 323                 $res = $dbr->select(
 324                         'watchlist',
 325                         [ 'wl_title', 'wl_namespace', 'watchers' => 'COUNT(*)' ],
 326                         [ $lb->constructSet( 'wl', $dbr ) ],
 327                         __METHOD__,
 328                         $dbOptions
 329                 );
 330
 331                 $this->reuseConnection( $dbr );
 332
 333                 $watchCounts = [];
 334                 foreach ( $targets as $linkTarget ) {
 335                         $watchCounts[$linkTarget->getNamespace()][$linkTarget->getDBkey()] = 0;
 336                 }
 337
 338                 foreach ( $res as $row ) {
 339                         $watchCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 340                 }
 341
 342                 return $watchCounts;
 343         }
 344
 345         /**
 346          * Number of watchers of each page who have visited recent edits to that page
 347          *
 348          * @param array $targetsWithVisitThresholds array of pairs (LinkTarget $target, mixed $threshold),
 349          *        $threshold is:
 350          *        - a timestamp of the recent edit if $target exists (format accepted by wfTimestamp)
 351          *        - null if $target doesn't exist
 352          * @param int|null $minimumWatchers
 353          * @return array multi-dimensional like $return[$namespaceId][$titleString] = $watchers,
 354          *         where $watchers is an int:
 355          *         - if the page exists, number of users watching who have visited the page recently
 356          *         - if the page doesn't exist, number of users that have the page on their watchlist
 357          *         - 0 means there are no visiting watchers or their number is below the minimumWatchers
 358          *         option (if passed).
 359          */
 360         public function countVisitingWatchersMultiple(
 361                 array $targetsWithVisitThresholds,
 362                 $minimumWatchers = null
 363         ) {
 364                 $dbr = $this->getConnection( DB_SLAVE );
 365
 366                 $conds = $this->getVisitingWatchersCondition( $dbr, $targetsWithVisitThresholds );
 367
 368                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 369                 if ( $minimumWatchers !== null ) {
 370                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$minimumWatchers;
 371                 }
 372                 $res = $dbr->select(
 373                         'watchlist',
 374                         [ 'wl_namespace', 'wl_title', 'watchers' => 'COUNT(*)' ],
 375                         $conds,
 376                         __METHOD__,
 377                         $dbOptions
 378                 );
 379
 380                 $this->reuseConnection( $dbr );
 381
 382                 $watcherCounts = [];
 383                 foreach ( $targetsWithVisitThresholds as list( $target ) ) {
 384                         /* @var LinkTarget $target */
 385                         $watcherCounts[$target->getNamespace()][$target->getDBkey()] = 0;
 386                 }
 387
 388                 foreach ( $res as $row ) {
 389                         $watcherCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 390                 }
 391
 392                 return $watcherCounts;
 393         }
 394
 395         /**
 396          * Generates condition for the query used in a batch count visiting watchers.
 397          *
 398          * @param IDatabase $db
 399          * @param array $targetsWithVisitThresholds array of pairs (LinkTarget, last visit threshold)
 400          * @return string
 401          */
 402         private function getVisitingWatchersCondition(
 403                 IDatabase $db,
 404                 array $targetsWithVisitThresholds
 405         ) {
 406                 $missingTargets = [];
 407                 $namespaceConds = [];
 408                 foreach ( $targetsWithVisitThresholds as list( $target, $threshold ) ) {
 409                         if ( $threshold === null ) {
 410                                 $missingTargets[] = $target;
 411                                 continue;
 412                         }
 413                         /* @var LinkTarget $target */
 414                         $namespaceConds[$target->getNamespace()][] = $db->makeList( [
 415                                 'wl_title = ' . $db->addQuotes( $target->getDBkey() ),
 416                                 $db->makeList( [
 417                                         'wl_notificationtimestamp >= ' . $db->addQuotes( $db->timestamp( $threshold ) ),
 418                                         'wl_notificationtimestamp IS NULL'
 419                                 ], LIST_OR )
 420                         ], LIST_AND );
 421                 }
 422
 423                 $conds = [];
 424                 foreach ( $namespaceConds as $namespace => $pageConds ) {
 425                         $conds[] = $db->makeList( [
 426                                 'wl_namespace = ' . $namespace,
 427                                 '(' . $db->makeList( $pageConds, LIST_OR ) . ')'
 428                         ], LIST_AND );
 429                 }
 430
 431                 if ( $missingTargets ) {
 432                         $lb = new LinkBatch( $missingTargets );
 433                         $conds[] = $lb->constructSet( 'wl', $db );
 434                 }
 435
 436                 return $db->makeList( $conds, LIST_OR );
 437         }
 438
 439         /**
 440          * Get an item (may be cached)
 441          *
 442          * @param User $user
 443          * @param LinkTarget $target
 444          *
 445          * @return WatchedItem|false
 446          */
 447         public function getWatchedItem( User $user, LinkTarget $target ) {
 448                 if ( $user->isAnon() ) {
 449                         return false;
 450                 }
 451
 452                 $cached = $this->getCached( $user, $target );
 453                 if ( $cached ) {
 454                         return $cached;
 455                 }
 456                 return $this->loadWatchedItem( $user, $target );
 457         }
 458
 459         /**
 460          * Loads an item from the db
 461          *
 462          * @param User $user
 463          * @param LinkTarget $target
 464          *
 465          * @return WatchedItem|false
 466          */
 467         public function loadWatchedItem( User $user, LinkTarget $target ) {
 468                 // Only loggedin user can have a watchlist
 469                 if ( $user->isAnon() ) {
 470                         return false;
 471                 }
 472
 473                 $dbr = $this->getConnection( DB_SLAVE );
 474                 $row = $dbr->selectRow(
 475                         'watchlist',
 476                         'wl_notificationtimestamp',
 477                         $this->dbCond( $user, $target ),
 478                         __METHOD__
 479                 );
 480                 $this->reuseConnection( $dbr );
 481
 482                 if ( !$row ) {
 483                         return false;
 484                 }
 485
 486                 $item = new WatchedItem(
 487                         $user,
 488                         $target,
 489                         $row->wl_notificationtimestamp
 490                 );
 491                 $this->cache( $item );
 492
 493                 return $item;
 494         }
 495
 496         /**
 497          * @param User $user
 498          * @param array $options Allowed keys:
 499          *        'forWrite' => bool defaults to false
 500          *        'sort' => string optional sorting by namespace ID and title
 501          *                     one of the self::SORT_* constants
 502          *
 503          * @return WatchedItem[]
 504          */
 505         public function getWatchedItemsForUser( User $user, array $options = [] ) {
 506                 $options += [ 'forWrite' => false ];
 507
 508                 $dbOptions = [];
 509                 if ( array_key_exists( 'sort', $options ) ) {
 510                         Assert::parameter(
 511                                 ( in_array( $options['sort'], [ self::SORT_ASC, self::SORT_DESC ] ) ),
 512                                 '$options[\'sort\']',
 513                                 'must be SORT_ASC or SORT_DESC'
 514                         );
 515                         $dbOptions['ORDER BY'] = [
 516                                 "wl_namespace {$options['sort']}",
 517                                 "wl_title {$options['sort']}"
 518                         ];
 519                 }
 520                 $db = $this->getConnection( $options['forWrite'] ? DB_MASTER : DB_SLAVE );
 521
 522                 $res = $db->select(
 523                         'watchlist',
 524                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 525                         [ 'wl_user' => $user->getId() ],
 526                         __METHOD__,
 527                         $dbOptions
 528                 );
 529                 $this->reuseConnection( $db );
 530
 531                 $watchedItems = [];
 532                 foreach ( $res as $row ) {
 533                         // todo these could all be cached at some point?
 534                         $watchedItems[] = new WatchedItem(
 535                                 $user,
 536                                 new TitleValue( (int)$row->wl_namespace, $row->wl_title ),
 537                                 $row->wl_notificationtimestamp
 538                         );
 539                 }
 540
 541                 return $watchedItems;
 542         }
 543
 544         /**
 545          * Must be called separately for Subject & Talk namespaces
 546          *
 547          * @param User $user
 548          * @param LinkTarget $target
 549          *
 550          * @return bool
 551          */
 552         public function isWatched( User $user, LinkTarget $target ) {
 553                 return (bool)$this->getWatchedItem( $user, $target );
 554         }
 555
 556         /**
 557          * @param User $user
 558          * @param LinkTarget[] $targets
 559          *
 560          * @return array multi-dimensional like $return[$namespaceId][$titleString] = $timestamp,
 561          *         where $timestamp is:
 562          *         - string|null value of wl_notificationtimestamp,
 563          *         - false if $target is not watched by $user.
 564          */
 565         public function getNotificationTimestampsBatch( User $user, array $targets ) {
 566                 $timestamps = [];
 567                 foreach ( $targets as $target ) {
 568                         $timestamps[$target->getNamespace()][$target->getDBkey()] = false;
 569                 }
 570
 571                 if ( $user->isAnon() ) {
 572                         return $timestamps;
 573                 }
 574
 575                 $targetsToLoad = [];
 576                 foreach ( $targets as $target ) {
 577                         $cachedItem = $this->getCached( $user, $target );
 578                         if ( $cachedItem ) {
 579                                 $timestamps[$target->getNamespace()][$target->getDBkey()] =
 580                                         $cachedItem->getNotificationTimestamp();
 581                         } else {
 582                                 $targetsToLoad[] = $target;
 583                         }
 584                 }
 585
 586                 if ( !$targetsToLoad ) {
 587                         return $timestamps;
 588                 }
 589
 590                 $dbr = $this->getConnection( DB_SLAVE );
 591
 592                 $lb = new LinkBatch( $targetsToLoad );
 593                 $res = $dbr->select(
 594                         'watchlist',
 595                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 596                         [
 597                                 $lb->constructSet( 'wl', $dbr ),
 598                                 'wl_user' => $user->getId(),
 599                         ],
 600                         __METHOD__
 601                 );
 602                 $this->reuseConnection( $dbr );
 603
 604                 foreach ( $res as $row ) {
 605                         $timestamps[(int)$row->wl_namespace][$row->wl_title] = $row->wl_notificationtimestamp;
 606                 }
 607
 608                 return $timestamps;
 609         }
 610
 611         /**
 612          * Must be called separately for Subject & Talk namespaces
 613          *
 614          * @param User $user
 615          * @param LinkTarget $target
 616          */
 617         public function addWatch( User $user, LinkTarget $target ) {
 618                 $this->addWatchBatchForUser( $user, [ $target ] );
 619         }
 620
 621         /**
 622          * @param User $user
 623          * @param LinkTarget[] $targets
 624          *
 625          * @return bool success
 626          */
 627         public function addWatchBatchForUser( User $user, array $targets ) {
 628                 if ( $this->loadBalancer->getReadOnlyReason() !== false ) {
 629                         return false;
 630                 }
 631                 // Only loggedin user can have a watchlist
 632                 if ( $user->isAnon() ) {
 633                         return false;
 634                 }
 635
 636                 if ( !$targets ) {
 637                         return true;
 638                 }
 639
 640                 $rows = [];
 641                 foreach ( $targets as $target ) {
 642                         $rows[] = [
 643                                 'wl_user' => $user->getId(),
 644                                 'wl_namespace' => $target->getNamespace(),
 645                                 'wl_title' => $target->getDBkey(),
 646                                 'wl_notificationtimestamp' => null,
 647                         ];
 648                         $this->uncache( $user, $target );
 649                 }
 650
 651                 $dbw = $this->getConnection( DB_MASTER );
 652                 foreach ( array_chunk( $rows, 100 ) as $toInsert ) {
 653                         // Use INSERT IGNORE to avoid overwriting the notification timestamp
 654                         // if there's already an entry for this page
 655                         $dbw->insert( 'watchlist', $toInsert, __METHOD__, 'IGNORE' );
 656                 }
 657                 $this->reuseConnection( $dbw );
 658
 659                 return true;
 660         }
 661
 662         /**
 663          * Removes the an entry for the User watching the LinkTarget
 664          * Must be called separately for Subject & Talk namespaces
 665          *
 666          * @param User $user
 667          * @param LinkTarget $target
 668          *
 669          * @return bool success
 670          * @throws DBUnexpectedError
 671          * @throws MWException
 672          */
 673         public function removeWatch( User $user, LinkTarget $target ) {
 674                 // Only logged in user can have a watchlist
 675                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 676                         return false;
 677                 }
 678
 679                 $this->uncache( $user, $target );
 680
 681                 $dbw = $this->getConnection( DB_MASTER );
 682                 $dbw->delete( 'watchlist',
 683                         [
 684                                 'wl_user' => $user->getId(),
 685                                 'wl_namespace' => $target->getNamespace(),
 686                                 'wl_title' => $target->getDBkey(),
 687                         ], __METHOD__
 688                 );
 689                 $success = (bool)$dbw->affectedRows();
 690                 $this->reuseConnection( $dbw );
 691
 692                 return $success;
 693         }
 694
 695         /**
 696          * @param User $editor The editor that triggered the update. Their notification
 697          *  timestamp will not be updated(they have already seen it)
 698          * @param LinkTarget $target The target to update timestamps for
 699          * @param string $timestamp Set the update timestamp to this value
 700          *
 701          * @return int[] Array of user IDs the timestamp has been updated for
 702          */
 703         public function updateNotificationTimestamp( User $editor, LinkTarget $target, $timestamp ) {
 704                 $dbw = $this->getConnection( DB_MASTER );
 705                 $res = $dbw->select( [ 'watchlist' ],
 706                         [ 'wl_user' ],
 707                         [
 708                                 'wl_user != ' . intval( $editor->getId() ),
 709                                 'wl_namespace' => $target->getNamespace(),
 710                                 'wl_title' => $target->getDBkey(),
 711                                 'wl_notificationtimestamp IS NULL',
 712                         ], __METHOD__
 713                 );
 714
 715                 $watchers = [];
 716                 foreach ( $res as $row ) {
 717                         $watchers[] = intval( $row->wl_user );
 718                 }
 719
 720                 if ( $watchers ) {
 721                         // Update wl_notificationtimestamp for all watching users except the editor
 722                         $fname = __METHOD__;
 723                         $dbw->onTransactionIdle(
 724                                 function () use ( $dbw, $timestamp, $watchers, $target, $fname ) {
 725                                         $dbw->update( 'watchlist',
 726                                                 [ /* SET */
 727                                                         'wl_notificationtimestamp' => $dbw->timestamp( $timestamp )
 728                                                 ], [ /* WHERE */
 729                                                         'wl_user' => $watchers,
 730                                                         'wl_namespace' => $target->getNamespace(),
 731                                                         'wl_title' => $target->getDBkey(),
 732                                                 ], $fname
 733                                         );
 734                                         $this->uncacheLinkTarget( $target );
 735                                 }
 736                         );
 737                 }
 738
 739                 $this->reuseConnection( $dbw );
 740
 741                 return $watchers;
 742         }
 743
 744         /**
 745          * Reset the notification timestamp of this entry
 746          *
 747          * @param User $user
 748          * @param Title $title
 749          * @param string $force Whether to force the write query to be executed even if the
 750          *    page is not watched or the notification timestamp is already NULL.
 751          *    'force' in order to force
 752          * @param int $oldid The revision id being viewed. If not given or 0, latest revision is assumed.
 753          *
 754          * @return bool success
 755          */
 756         public function resetNotificationTimestamp( User $user, Title $title, $force = '', $oldid = 0 ) {
 757                 // Only loggedin user can have a watchlist
 758                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 759                         return false;
 760                 }
 761
 762                 $item = null;
 763                 if ( $force != 'force' ) {
 764                         $item = $this->loadWatchedItem( $user, $title );
 765                         if ( !$item || $item->getNotificationTimestamp() === null ) {
 766                                 return false;
 767                         }
 768                 }
 769
 770                 // If the page is watched by the user (or may be watched), update the timestamp
 771                 $job = new ActivityUpdateJob(
 772                         $title,
 773                         [
 774                                 'type'      => 'updateWatchlistNotification',
 775                                 'userid'    => $user->getId(),
 776                                 'notifTime' => $this->getNotificationTimestamp( $user, $title, $item, $force, $oldid ),
 777                                 'curTime'   => time()
 778                         ]
 779                 );
 780
 781                 // Try to run this post-send
 782                 // Calls DeferredUpdates::addCallableUpdate in normal operation
 783                 call_user_func(
 784                         $this->deferredUpdatesAddCallableUpdateCallback,
 785                         function() use ( $job ) {
 786                                 $job->run();
 787                         }
 788                 );
 789
 790                 $this->uncache( $user, $title );
 791
 792                 return true;
 793         }
 794
 795         private function getNotificationTimestamp( User $user, Title $title, $item, $force, $oldid ) {
 796                 if ( !$oldid ) {
 797                         // No oldid given, assuming latest revision; clear the timestamp.
 798                         return null;
 799                 }
 800
 801                 if ( !$title->getNextRevisionID( $oldid ) ) {
 802                         // Oldid given and is the latest revision for this title; clear the timestamp.
 803                         return null;
 804                 }
 805
 806                 if ( $item === null ) {
 807                         $item = $this->loadWatchedItem( $user, $title );
 808                 }
 809
 810                 if ( !$item ) {
 811                         // This can only happen if $force is enabled.
 812                         return null;
 813                 }
 814
 815                 // Oldid given and isn't the latest; update the timestamp.
 816                 // This will result in no further notification emails being sent!
 817                 // Calls Revision::getTimestampFromId in normal operation
 818                 $notificationTimestamp = call_user_func(
 819                         $this->revisionGetTimestampFromIdCallback,
 820                         $title,
 821                         $oldid
 822                 );
 823
 824                 // We need to go one second to the future because of various strict comparisons
 825                 // throughout the codebase
 826                 $ts = new MWTimestamp( $notificationTimestamp );
 827                 $ts->timestamp->add( new DateInterval( 'PT1S' ) );
 828                 $notificationTimestamp = $ts->getTimestamp( TS_MW );
 829
 830                 if ( $notificationTimestamp < $item->getNotificationTimestamp() ) {
 831                         if ( $force != 'force' ) {
 832                                 return false;
 833                         } else {
 834                                 // This is a little silly…
 835                                 return $item->getNotificationTimestamp();
 836                         }
 837                 }
 838
 839                 return $notificationTimestamp;
 840         }
 841
 842         /**
 843          * @param User $user
 844          * @param int $unreadLimit
 845          *
 846          * @return int|bool The number of unread notifications
 847          *                  true if greater than or equal to $unreadLimit
 848          */
 849         public function countUnreadNotifications( User $user, $unreadLimit = null ) {
 850                 $queryOptions = [];
 851                 if ( $unreadLimit !== null ) {
 852                         $unreadLimit = (int)$unreadLimit;
 853                         $queryOptions['LIMIT'] = $unreadLimit;
 854                 }
 855
 856                 $dbr = $this->getConnection( DB_SLAVE );
 857                 $rowCount = $dbr->selectRowCount(
 858                         'watchlist',
 859                         '1',
 860                         [
 861                                 'wl_user' => $user->getId(),
 862                                 'wl_notificationtimestamp IS NOT NULL',
 863                         ],
 864                         __METHOD__,
 865                         $queryOptions
 866                 );
 867                 $this->reuseConnection( $dbr );
 868
 869                 if ( !isset( $unreadLimit ) ) {
 870                         return $rowCount;
 871                 }
 872
 873                 if ( $rowCount >= $unreadLimit ) {
 874                         return true;
 875                 }
 876
 877                 return $rowCount;
 878         }
 879
 880         /**
 881          * Check if the given title already is watched by the user, and if so
 882          * add a watch for the new title.
 883          *
 884          * To be used for page renames and such.
 885          *
 886          * @param LinkTarget $oldTarget
 887          * @param LinkTarget $newTarget
 888          */
 889         public function duplicateAllAssociatedEntries( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 890                 if ( !$oldTarget instanceof Title ) {
 891                         $oldTarget = Title::newFromLinkTarget( $oldTarget );
 892                 }
 893                 if ( !$newTarget instanceof Title ) {
 894                         $newTarget = Title::newFromLinkTarget( $newTarget );
 895                 }
 896
 897                 $this->duplicateEntry( $oldTarget->getSubjectPage(), $newTarget->getSubjectPage() );
 898                 $this->duplicateEntry( $oldTarget->getTalkPage(), $newTarget->getTalkPage() );
 899         }
 900
 901         /**
 902          * Check if the given title already is watched by the user, and if so
 903          * add a watch for the new title.
 904          *
 905          * To be used for page renames and such.
 906          * This must be called separately for Subject and Talk pages
 907          *
 908          * @param LinkTarget $oldTarget
 909          * @param LinkTarget $newTarget
 910          */
 911         public function duplicateEntry( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 912                 $dbw = $this->getConnection( DB_MASTER );
 913
 914                 $result = $dbw->select(
 915                         'watchlist',
 916                         [ 'wl_user', 'wl_notificationtimestamp' ],
 917                         [
 918                                 'wl_namespace' => $oldTarget->getNamespace(),
 919                                 'wl_title' => $oldTarget->getDBkey(),
 920                         ],
 921                         __METHOD__,
 922                         [ 'FOR UPDATE' ]
 923                 );
 924
 925                 $newNamespace = $newTarget->getNamespace();
 926                 $newDBkey = $newTarget->getDBkey();
 927
 928                 # Construct array to replace into the watchlist
 929                 $values = [];
 930                 foreach ( $result as $row ) {
 931                         $values[] = [
 932                                 'wl_user' => $row->wl_user,
 933                                 'wl_namespace' => $newNamespace,
 934                                 'wl_title' => $newDBkey,
 935                                 'wl_notificationtimestamp' => $row->wl_notificationtimestamp,
 936                         ];
 937                 }
 938
 939                 if ( !empty( $values ) ) {
 940                         # Perform replace
 941                         # Note that multi-row replace is very efficient for MySQL but may be inefficient for
 942                         # some other DBMSes, mostly due to poor simulation by us
 943                         $dbw->replace(
 944                                 'watchlist',
 945                                 [ [ 'wl_user', 'wl_namespace', 'wl_title' ] ],
 946                                 $values,
 947                                 __METHOD__
 948                         );
 949                 }
 950
 951                 $this->reuseConnection( $dbw );
 952         }
 953
 954 }