includes/WatchedItemStore.php

   1 <?php
   2
   3 use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
   4 use MediaWiki\Linker\LinkTarget;
   5 use Wikimedia\Assert\Assert;
   6
   7 /**
   8  * Storage layer class for WatchedItems.
   9  * Database interaction.
  10  *
  11  * @author Addshore
  12  *
  13  * @since 1.27
  14  */
  15 class WatchedItemStore implements StatsdAwareInterface {
  16
  17         const SORT_DESC = 'DESC';
  18         const SORT_ASC = 'ASC';
  19
  20         /**
  21          * @var LoadBalancer
  22          */
  23         private $loadBalancer;
  24
  25         /**
  26          * @var HashBagOStuff
  27          */
  28         private $cache;
  29
  30         /**
  31          * @var array[] Looks like $cacheIndex[Namespace ID][Target DB Key][User Id] => 'key'
  32          * The index is needed so that on mass changes all relevant items can be un-cached.
  33          * For example: Clearing a users watchlist of all items or updating notification timestamps
  34          *              for all users watching a single target.
  35          */
  36         private $cacheIndex = [];
  37
  38         /**
  39          * @var callable|null
  40          */
  41         private $deferredUpdatesAddCallableUpdateCallback;
  42
  43         /**
  44          * @var callable|null
  45          */
  46         private $revisionGetTimestampFromIdCallback;
  47
  48         /**
  49          * @var StatsdDataFactoryInterface
  50          */
  51         private $stats;
  52
  53         /**
  54          * @var self|null
  55          */
  56         private static $instance;
  57
  58         /**
  59          * @param LoadBalancer $loadBalancer
  60          * @param HashBagOStuff $cache
  61          */
  62         public function __construct(
  63                 LoadBalancer $loadBalancer,
  64                 HashBagOStuff $cache
  65         ) {
  66                 $this->loadBalancer = $loadBalancer;
  67                 $this->cache = $cache;
  68                 $this->stats = new NullStatsdDataFactory();
  69                 $this->deferredUpdatesAddCallableUpdateCallback = [ 'DeferredUpdates', 'addCallableUpdate' ];
  70                 $this->revisionGetTimestampFromIdCallback = [ 'Revision', 'getTimestampFromId' ];
  71         }
  72
  73         public function setStatsdDataFactory( StatsdDataFactoryInterface $stats ) {
  74                 $this->stats = $stats;
  75         }
  76
  77         /**
  78          * Overrides the DeferredUpdates::addCallableUpdate callback
  79          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
  80          *
  81          * @param callable $callback
  82          *
  83          * @see DeferredUpdates::addCallableUpdate for callback signiture
  84          *
  85          * @return ScopedCallback to reset the overridden value
  86          * @throws MWException
  87          */
  88         public function overrideDeferredUpdatesAddCallableUpdateCallback( $callback ) {
  89                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
  90                         throw new MWException(
  91                                 'Cannot override DeferredUpdates::addCallableUpdate callback in operation.'
  92                         );
  93                 }
  94                 Assert::parameterType( 'callable', $callback, '$callback' );
  95
  96                 $previousValue = $this->deferredUpdatesAddCallableUpdateCallback;
  97                 $this->deferredUpdatesAddCallableUpdateCallback = $callback;
  98                 return new ScopedCallback( function() use ( $previousValue ) {
  99                         $this->deferredUpdatesAddCallableUpdateCallback = $previousValue;
 100                 } );
 101         }
 102
 103         /**
 104          * Overrides the Revision::getTimestampFromId callback
 105          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
 106          *
 107          * @param callable $callback
 108          * @see Revision::getTimestampFromId for callback signiture
 109          *
 110          * @return ScopedCallback to reset the overridden value
 111          * @throws MWException
 112          */
 113         public function overrideRevisionGetTimestampFromIdCallback( $callback ) {
 114                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 115                         throw new MWException(
 116                                 'Cannot override Revision::getTimestampFromId callback in operation.'
 117                         );
 118                 }
 119                 Assert::parameterType( 'callable', $callback, '$callback' );
 120
 121                 $previousValue = $this->revisionGetTimestampFromIdCallback;
 122                 $this->revisionGetTimestampFromIdCallback = $callback;
 123                 return new ScopedCallback( function() use ( $previousValue ) {
 124                         $this->revisionGetTimestampFromIdCallback = $previousValue;
 125                 } );
 126         }
 127
 128         /**
 129          * Overrides the default instance of this class
 130          * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
 131          *
 132          * If this method is used it MUST also be called with null after a test to ensure a new
 133          * default instance is created next time getDefaultInstance is called.
 134          *
 135          * @param WatchedItemStore|null $store
 136          *
 137          * @return ScopedCallback to reset the overridden value
 138          * @throws MWException
 139          */
 140         public static function overrideDefaultInstance( WatchedItemStore $store = null ) {
 141                 if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
 142                         throw new MWException(
 143                                 'Cannot override ' . __CLASS__ . 'default instance in operation.'
 144                         );
 145                 }
 146
 147                 $previousValue = self::$instance;
 148                 self::$instance = $store;
 149                 return new ScopedCallback( function() use ( $previousValue ) {
 150                         self::$instance = $previousValue;
 151                 } );
 152         }
 153
 154         /**
 155          * @return self
 156          */
 157         public static function getDefaultInstance() {
 158                 if ( !self::$instance ) {
 159                         self::$instance = new self(
 160                                 wfGetLB(),
 161                                 new HashBagOStuff( [ 'maxKeys' => 100 ] )
 162                         );
 163                         self::$instance->setStatsdDataFactory( RequestContext::getMain()->getStats() );
 164                 }
 165                 return self::$instance;
 166         }
 167
 168         private function getCacheKey( User $user, LinkTarget $target ) {
 169                 return $this->cache->makeKey(
 170                         (string)$target->getNamespace(),
 171                         $target->getDBkey(),
 172                         (string)$user->getId()
 173                 );
 174         }
 175
 176         private function cache( WatchedItem $item ) {
 177                 $user = $item->getUser();
 178                 $target = $item->getLinkTarget();
 179                 $key = $this->getCacheKey( $user, $target );
 180                 $this->cache->set( $key, $item );
 181                 $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] = $key;
 182                 $this->stats->increment( 'WatchedItemStore.cache' );
 183         }
 184
 185         private function uncache( User $user, LinkTarget $target ) {
 186                 $this->cache->delete( $this->getCacheKey( $user, $target ) );
 187                 unset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()][$user->getId()] );
 188                 $this->stats->increment( 'WatchedItemStore.uncache' );
 189         }
 190
 191         private function uncacheLinkTarget( LinkTarget $target ) {
 192                 if ( !isset( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] ) ) {
 193                         return;
 194                 }
 195                 $this->stats->increment( 'WatchedItemStore.uncacheLinkTarget' );
 196                 foreach ( $this->cacheIndex[$target->getNamespace()][$target->getDBkey()] as $key ) {
 197                         $this->stats->increment( 'WatchedItemStore.uncacheLinkTarget.items' );
 198                         $this->cache->delete( $key );
 199                 }
 200         }
 201
 202         /**
 203          * @param User $user
 204          * @param LinkTarget $target
 205          *
 206          * @return WatchedItem|null
 207          */
 208         private function getCached( User $user, LinkTarget $target ) {
 209                 return $this->cache->get( $this->getCacheKey( $user, $target ) );
 210         }
 211
 212         /**
 213          * Return an array of conditions to select or update the appropriate database
 214          * row.
 215          *
 216          * @param User $user
 217          * @param LinkTarget $target
 218          *
 219          * @return array
 220          */
 221         private function dbCond( User $user, LinkTarget $target ) {
 222                 return [
 223                         'wl_user' => $user->getId(),
 224                         'wl_namespace' => $target->getNamespace(),
 225                         'wl_title' => $target->getDBkey(),
 226                 ];
 227         }
 228
 229         /**
 230          * @param int $slaveOrMaster DB_MASTER or DB_SLAVE
 231          *
 232          * @return DatabaseBase
 233          * @throws MWException
 234          */
 235         private function getConnection( $slaveOrMaster ) {
 236                 return $this->loadBalancer->getConnection( $slaveOrMaster, [ 'watchlist' ] );
 237         }
 238
 239         /**
 240          * @param DatabaseBase $connection
 241          *
 242          * @throws MWException
 243          */
 244         private function reuseConnection( $connection ) {
 245                 $this->loadBalancer->reuseConnection( $connection );
 246         }
 247
 248         /**
 249          * Count the number of individual items that are watched by the user.
 250          * If a subject and corresponding talk page are watched this will return 2.
 251          *
 252          * @param User $user
 253          *
 254          * @return int
 255          */
 256         public function countWatchedItems( User $user ) {
 257                 $dbr = $this->getConnection( DB_SLAVE );
 258                 $return = (int)$dbr->selectField(
 259                         'watchlist',
 260                         'COUNT(*)',
 261                         [
 262                                 'wl_user' => $user->getId()
 263                         ],
 264                         __METHOD__
 265                 );
 266                 $this->reuseConnection( $dbr );
 267
 268                 return $return;
 269         }
 270
 271         /**
 272          * @param LinkTarget $target
 273          *
 274          * @return int
 275          */
 276         public function countWatchers( LinkTarget $target ) {
 277                 $dbr = $this->getConnection( DB_SLAVE );
 278                 $return = (int)$dbr->selectField(
 279                         'watchlist',
 280                         'COUNT(*)',
 281                         [
 282                                 'wl_namespace' => $target->getNamespace(),
 283                                 'wl_title' => $target->getDBkey(),
 284                         ],
 285                         __METHOD__
 286                 );
 287                 $this->reuseConnection( $dbr );
 288
 289                 return $return;
 290         }
 291
 292         /**
 293          * Number of page watchers who also visited a "recent" edit
 294          *
 295          * @param LinkTarget $target
 296          * @param mixed $threshold timestamp accepted by wfTimestamp
 297          *
 298          * @return int
 299          * @throws DBUnexpectedError
 300          * @throws MWException
 301          */
 302         public function countVisitingWatchers( LinkTarget $target, $threshold ) {
 303                 $dbr = $this->getConnection( DB_SLAVE );
 304                 $visitingWatchers = (int)$dbr->selectField(
 305                         'watchlist',
 306                         'COUNT(*)',
 307                         [
 308                                 'wl_namespace' => $target->getNamespace(),
 309                                 'wl_title' => $target->getDBkey(),
 310                                 'wl_notificationtimestamp >= ' .
 311                                 $dbr->addQuotes( $dbr->timestamp( $threshold ) ) .
 312                                 ' OR wl_notificationtimestamp IS NULL'
 313                         ],
 314                         __METHOD__
 315                 );
 316                 $this->reuseConnection( $dbr );
 317
 318                 return $visitingWatchers;
 319         }
 320
 321         /**
 322          * @param LinkTarget[] $targets
 323          * @param array $options Allowed keys:
 324          *        'minimumWatchers' => int
 325          *
 326          * @return array multi dimensional like $return[$namespaceId][$titleString] = int $watchers
 327          *         All targets will be present in the result. 0 either means no watchers or the number
 328          *         of watchers was below the minimumWatchers option if passed.
 329          */
 330         public function countWatchersMultiple( array $targets, array $options = [] ) {
 331                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 332
 333                 $dbr = $this->getConnection( DB_SLAVE );
 334
 335                 if ( array_key_exists( 'minimumWatchers', $options ) ) {
 336                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$options['minimumWatchers'];
 337                 }
 338
 339                 $lb = new LinkBatch( $targets );
 340                 $res = $dbr->select(
 341                         'watchlist',
 342                         [ 'wl_title', 'wl_namespace', 'watchers' => 'COUNT(*)' ],
 343                         [ $lb->constructSet( 'wl', $dbr ) ],
 344                         __METHOD__,
 345                         $dbOptions
 346                 );
 347
 348                 $this->reuseConnection( $dbr );
 349
 350                 $watchCounts = [];
 351                 foreach ( $targets as $linkTarget ) {
 352                         $watchCounts[$linkTarget->getNamespace()][$linkTarget->getDBkey()] = 0;
 353                 }
 354
 355                 foreach ( $res as $row ) {
 356                         $watchCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 357                 }
 358
 359                 return $watchCounts;
 360         }
 361
 362         /**
 363          * Number of watchers of each page who have visited recent edits to that page
 364          *
 365          * @param array $targetsWithVisitThresholds array of pairs (LinkTarget $target, mixed $threshold),
 366          *        $threshold is:
 367          *        - a timestamp of the recent edit if $target exists (format accepted by wfTimestamp)
 368          *        - null if $target doesn't exist
 369          * @param int|null $minimumWatchers
 370          * @return array multi-dimensional like $return[$namespaceId][$titleString] = $watchers,
 371          *         where $watchers is an int:
 372          *         - if the page exists, number of users watching who have visited the page recently
 373          *         - if the page doesn't exist, number of users that have the page on their watchlist
 374          *         - 0 means there are no visiting watchers or their number is below the minimumWatchers
 375          *         option (if passed).
 376          */
 377         public function countVisitingWatchersMultiple(
 378                 array $targetsWithVisitThresholds,
 379                 $minimumWatchers = null
 380         ) {
 381                 $dbr = $this->getConnection( DB_SLAVE );
 382
 383                 $conds = $this->getVisitingWatchersCondition( $dbr, $targetsWithVisitThresholds );
 384
 385                 $dbOptions = [ 'GROUP BY' => [ 'wl_namespace', 'wl_title' ] ];
 386                 if ( $minimumWatchers !== null ) {
 387                         $dbOptions['HAVING'] = 'COUNT(*) >= ' . (int)$minimumWatchers;
 388                 }
 389                 $res = $dbr->select(
 390                         'watchlist',
 391                         [ 'wl_namespace', 'wl_title', 'watchers' => 'COUNT(*)' ],
 392                         $conds,
 393                         __METHOD__,
 394                         $dbOptions
 395                 );
 396
 397                 $this->reuseConnection( $dbr );
 398
 399                 $watcherCounts = [];
 400                 foreach ( $targetsWithVisitThresholds as list( $target ) ) {
 401                         /* @var LinkTarget $target */
 402                         $watcherCounts[$target->getNamespace()][$target->getDBkey()] = 0;
 403                 }
 404
 405                 foreach ( $res as $row ) {
 406                         $watcherCounts[$row->wl_namespace][$row->wl_title] = (int)$row->watchers;
 407                 }
 408
 409                 return $watcherCounts;
 410         }
 411
 412         /**
 413          * Generates condition for the query used in a batch count visiting watchers.
 414          *
 415          * @param IDatabase $db
 416          * @param array $targetsWithVisitThresholds array of pairs (LinkTarget, last visit threshold)
 417          * @return string
 418          */
 419         private function getVisitingWatchersCondition(
 420                 IDatabase $db,
 421                 array $targetsWithVisitThresholds
 422         ) {
 423                 $missingTargets = [];
 424                 $namespaceConds = [];
 425                 foreach ( $targetsWithVisitThresholds as list( $target, $threshold ) ) {
 426                         if ( $threshold === null ) {
 427                                 $missingTargets[] = $target;
 428                                 continue;
 429                         }
 430                         /* @var LinkTarget $target */
 431                         $namespaceConds[$target->getNamespace()][] = $db->makeList( [
 432                                 'wl_title = ' . $db->addQuotes( $target->getDBkey() ),
 433                                 $db->makeList( [
 434                                         'wl_notificationtimestamp >= ' . $db->addQuotes( $db->timestamp( $threshold ) ),
 435                                         'wl_notificationtimestamp IS NULL'
 436                                 ], LIST_OR )
 437                         ], LIST_AND );
 438                 }
 439
 440                 $conds = [];
 441                 foreach ( $namespaceConds as $namespace => $pageConds ) {
 442                         $conds[] = $db->makeList( [
 443                                 'wl_namespace = ' . $namespace,
 444                                 '(' . $db->makeList( $pageConds, LIST_OR ) . ')'
 445                         ], LIST_AND );
 446                 }
 447
 448                 if ( $missingTargets ) {
 449                         $lb = new LinkBatch( $missingTargets );
 450                         $conds[] = $lb->constructSet( 'wl', $db );
 451                 }
 452
 453                 return $db->makeList( $conds, LIST_OR );
 454         }
 455
 456         /**
 457          * Get an item (may be cached)
 458          *
 459          * @param User $user
 460          * @param LinkTarget $target
 461          *
 462          * @return WatchedItem|false
 463          */
 464         public function getWatchedItem( User $user, LinkTarget $target ) {
 465                 if ( $user->isAnon() ) {
 466                         return false;
 467                 }
 468
 469                 $cached = $this->getCached( $user, $target );
 470                 if ( $cached ) {
 471                         $this->stats->increment( 'WatchedItemStore.getWatchedItem.cached' );
 472                         return $cached;
 473                 }
 474                 $this->stats->increment( 'WatchedItemStore.getWatchedItem.load' );
 475                 return $this->loadWatchedItem( $user, $target );
 476         }
 477
 478         /**
 479          * Loads an item from the db
 480          *
 481          * @param User $user
 482          * @param LinkTarget $target
 483          *
 484          * @return WatchedItem|false
 485          */
 486         public function loadWatchedItem( User $user, LinkTarget $target ) {
 487                 // Only loggedin user can have a watchlist
 488                 if ( $user->isAnon() ) {
 489                         return false;
 490                 }
 491
 492                 $dbr = $this->getConnection( DB_SLAVE );
 493                 $row = $dbr->selectRow(
 494                         'watchlist',
 495                         'wl_notificationtimestamp',
 496                         $this->dbCond( $user, $target ),
 497                         __METHOD__
 498                 );
 499                 $this->reuseConnection( $dbr );
 500
 501                 if ( !$row ) {
 502                         return false;
 503                 }
 504
 505                 $item = new WatchedItem(
 506                         $user,
 507                         $target,
 508                         $row->wl_notificationtimestamp
 509                 );
 510                 $this->cache( $item );
 511
 512                 return $item;
 513         }
 514
 515         /**
 516          * @param User $user
 517          * @param array $options Allowed keys:
 518          *        'forWrite' => bool defaults to false
 519          *        'sort' => string optional sorting by namespace ID and title
 520          *                     one of the self::SORT_* constants
 521          *
 522          * @return WatchedItem[]
 523          */
 524         public function getWatchedItemsForUser( User $user, array $options = [] ) {
 525                 $options += [ 'forWrite' => false ];
 526
 527                 $dbOptions = [];
 528                 if ( array_key_exists( 'sort', $options ) ) {
 529                         Assert::parameter(
 530                                 ( in_array( $options['sort'], [ self::SORT_ASC, self::SORT_DESC ] ) ),
 531                                 '$options[\'sort\']',
 532                                 'must be SORT_ASC or SORT_DESC'
 533                         );
 534                         $dbOptions['ORDER BY'] = [
 535                                 "wl_namespace {$options['sort']}",
 536                                 "wl_title {$options['sort']}"
 537                         ];
 538                 }
 539                 $db = $this->getConnection( $options['forWrite'] ? DB_MASTER : DB_SLAVE );
 540
 541                 $res = $db->select(
 542                         'watchlist',
 543                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 544                         [ 'wl_user' => $user->getId() ],
 545                         __METHOD__,
 546                         $dbOptions
 547                 );
 548                 $this->reuseConnection( $db );
 549
 550                 $watchedItems = [];
 551                 foreach ( $res as $row ) {
 552                         // todo these could all be cached at some point?
 553                         $watchedItems[] = new WatchedItem(
 554                                 $user,
 555                                 new TitleValue( (int)$row->wl_namespace, $row->wl_title ),
 556                                 $row->wl_notificationtimestamp
 557                         );
 558                 }
 559
 560                 return $watchedItems;
 561         }
 562
 563         /**
 564          * Must be called separately for Subject & Talk namespaces
 565          *
 566          * @param User $user
 567          * @param LinkTarget $target
 568          *
 569          * @return bool
 570          */
 571         public function isWatched( User $user, LinkTarget $target ) {
 572                 return (bool)$this->getWatchedItem( $user, $target );
 573         }
 574
 575         /**
 576          * @param User $user
 577          * @param LinkTarget[] $targets
 578          *
 579          * @return array multi-dimensional like $return[$namespaceId][$titleString] = $timestamp,
 580          *         where $timestamp is:
 581          *         - string|null value of wl_notificationtimestamp,
 582          *         - false if $target is not watched by $user.
 583          */
 584         public function getNotificationTimestampsBatch( User $user, array $targets ) {
 585                 $timestamps = [];
 586                 foreach ( $targets as $target ) {
 587                         $timestamps[$target->getNamespace()][$target->getDBkey()] = false;
 588                 }
 589
 590                 if ( $user->isAnon() ) {
 591                         return $timestamps;
 592                 }
 593
 594                 $targetsToLoad = [];
 595                 foreach ( $targets as $target ) {
 596                         $cachedItem = $this->getCached( $user, $target );
 597                         if ( $cachedItem ) {
 598                                 $timestamps[$target->getNamespace()][$target->getDBkey()] =
 599                                         $cachedItem->getNotificationTimestamp();
 600                         } else {
 601                                 $targetsToLoad[] = $target;
 602                         }
 603                 }
 604
 605                 if ( !$targetsToLoad ) {
 606                         return $timestamps;
 607                 }
 608
 609                 $dbr = $this->getConnection( DB_SLAVE );
 610
 611                 $lb = new LinkBatch( $targetsToLoad );
 612                 $res = $dbr->select(
 613                         'watchlist',
 614                         [ 'wl_namespace', 'wl_title', 'wl_notificationtimestamp' ],
 615                         [
 616                                 $lb->constructSet( 'wl', $dbr ),
 617                                 'wl_user' => $user->getId(),
 618                         ],
 619                         __METHOD__
 620                 );
 621                 $this->reuseConnection( $dbr );
 622
 623                 foreach ( $res as $row ) {
 624                         $timestamps[(int)$row->wl_namespace][$row->wl_title] = $row->wl_notificationtimestamp;
 625                 }
 626
 627                 return $timestamps;
 628         }
 629
 630         /**
 631          * Must be called separately for Subject & Talk namespaces
 632          *
 633          * @param User $user
 634          * @param LinkTarget $target
 635          */
 636         public function addWatch( User $user, LinkTarget $target ) {
 637                 $this->addWatchBatchForUser( $user, [ $target ] );
 638         }
 639
 640         /**
 641          * @param User $user
 642          * @param LinkTarget[] $targets
 643          *
 644          * @return bool success
 645          */
 646         public function addWatchBatchForUser( User $user, array $targets ) {
 647                 if ( $this->loadBalancer->getReadOnlyReason() !== false ) {
 648                         return false;
 649                 }
 650                 // Only loggedin user can have a watchlist
 651                 if ( $user->isAnon() ) {
 652                         return false;
 653                 }
 654
 655                 if ( !$targets ) {
 656                         return true;
 657                 }
 658
 659                 $rows = [];
 660                 foreach ( $targets as $target ) {
 661                         $rows[] = [
 662                                 'wl_user' => $user->getId(),
 663                                 'wl_namespace' => $target->getNamespace(),
 664                                 'wl_title' => $target->getDBkey(),
 665                                 'wl_notificationtimestamp' => null,
 666                         ];
 667                         $this->uncache( $user, $target );
 668                 }
 669
 670                 $dbw = $this->getConnection( DB_MASTER );
 671                 foreach ( array_chunk( $rows, 100 ) as $toInsert ) {
 672                         // Use INSERT IGNORE to avoid overwriting the notification timestamp
 673                         // if there's already an entry for this page
 674                         $dbw->insert( 'watchlist', $toInsert, __METHOD__, 'IGNORE' );
 675                 }
 676                 $this->reuseConnection( $dbw );
 677
 678                 return true;
 679         }
 680
 681         /**
 682          * Removes the an entry for the User watching the LinkTarget
 683          * Must be called separately for Subject & Talk namespaces
 684          *
 685          * @param User $user
 686          * @param LinkTarget $target
 687          *
 688          * @return bool success
 689          * @throws DBUnexpectedError
 690          * @throws MWException
 691          */
 692         public function removeWatch( User $user, LinkTarget $target ) {
 693                 // Only logged in user can have a watchlist
 694                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 695                         return false;
 696                 }
 697
 698                 $this->uncache( $user, $target );
 699
 700                 $dbw = $this->getConnection( DB_MASTER );
 701                 $dbw->delete( 'watchlist',
 702                         [
 703                                 'wl_user' => $user->getId(),
 704                                 'wl_namespace' => $target->getNamespace(),
 705                                 'wl_title' => $target->getDBkey(),
 706                         ], __METHOD__
 707                 );
 708                 $success = (bool)$dbw->affectedRows();
 709                 $this->reuseConnection( $dbw );
 710
 711                 return $success;
 712         }
 713
 714         /**
 715          * @param User $editor The editor that triggered the update. Their notification
 716          *  timestamp will not be updated(they have already seen it)
 717          * @param LinkTarget $target The target to update timestamps for
 718          * @param string $timestamp Set the update timestamp to this value
 719          *
 720          * @return int[] Array of user IDs the timestamp has been updated for
 721          */
 722         public function updateNotificationTimestamp( User $editor, LinkTarget $target, $timestamp ) {
 723                 $dbw = $this->getConnection( DB_MASTER );
 724                 $res = $dbw->select( [ 'watchlist' ],
 725                         [ 'wl_user' ],
 726                         [
 727                                 'wl_user != ' . intval( $editor->getId() ),
 728                                 'wl_namespace' => $target->getNamespace(),
 729                                 'wl_title' => $target->getDBkey(),
 730                                 'wl_notificationtimestamp IS NULL',
 731                         ], __METHOD__
 732                 );
 733
 734                 $watchers = [];
 735                 foreach ( $res as $row ) {
 736                         $watchers[] = intval( $row->wl_user );
 737                 }
 738
 739                 if ( $watchers ) {
 740                         // Update wl_notificationtimestamp for all watching users except the editor
 741                         $fname = __METHOD__;
 742                         $dbw->onTransactionIdle(
 743                                 function () use ( $dbw, $timestamp, $watchers, $target, $fname ) {
 744                                         $dbw->update( 'watchlist',
 745                                                 [ /* SET */
 746                                                         'wl_notificationtimestamp' => $dbw->timestamp( $timestamp )
 747                                                 ], [ /* WHERE */
 748                                                         'wl_user' => $watchers,
 749                                                         'wl_namespace' => $target->getNamespace(),
 750                                                         'wl_title' => $target->getDBkey(),
 751                                                 ], $fname
 752                                         );
 753                                         $this->uncacheLinkTarget( $target );
 754                                 }
 755                         );
 756                 }
 757
 758                 $this->reuseConnection( $dbw );
 759
 760                 return $watchers;
 761         }
 762
 763         /**
 764          * Reset the notification timestamp of this entry
 765          *
 766          * @param User $user
 767          * @param Title $title
 768          * @param string $force Whether to force the write query to be executed even if the
 769          *    page is not watched or the notification timestamp is already NULL.
 770          *    'force' in order to force
 771          * @param int $oldid The revision id being viewed. If not given or 0, latest revision is assumed.
 772          *
 773          * @return bool success
 774          */
 775         public function resetNotificationTimestamp( User $user, Title $title, $force = '', $oldid = 0 ) {
 776                 // Only loggedin user can have a watchlist
 777                 if ( $this->loadBalancer->getReadOnlyReason() !== false || $user->isAnon() ) {
 778                         return false;
 779                 }
 780
 781                 $item = null;
 782                 if ( $force != 'force' ) {
 783                         $item = $this->loadWatchedItem( $user, $title );
 784                         if ( !$item || $item->getNotificationTimestamp() === null ) {
 785                                 return false;
 786                         }
 787                 }
 788
 789                 // If the page is watched by the user (or may be watched), update the timestamp
 790                 $job = new ActivityUpdateJob(
 791                         $title,
 792                         [
 793                                 'type'      => 'updateWatchlistNotification',
 794                                 'userid'    => $user->getId(),
 795                                 'notifTime' => $this->getNotificationTimestamp( $user, $title, $item, $force, $oldid ),
 796                                 'curTime'   => time()
 797                         ]
 798                 );
 799
 800                 // Try to run this post-send
 801                 // Calls DeferredUpdates::addCallableUpdate in normal operation
 802                 call_user_func(
 803                         $this->deferredUpdatesAddCallableUpdateCallback,
 804                         function() use ( $job ) {
 805                                 $job->run();
 806                         }
 807                 );
 808
 809                 $this->uncache( $user, $title );
 810
 811                 return true;
 812         }
 813
 814         private function getNotificationTimestamp( User $user, Title $title, $item, $force, $oldid ) {
 815                 if ( !$oldid ) {
 816                         // No oldid given, assuming latest revision; clear the timestamp.
 817                         return null;
 818                 }
 819
 820                 if ( !$title->getNextRevisionID( $oldid ) ) {
 821                         // Oldid given and is the latest revision for this title; clear the timestamp.
 822                         return null;
 823                 }
 824
 825                 if ( $item === null ) {
 826                         $item = $this->loadWatchedItem( $user, $title );
 827                 }
 828
 829                 if ( !$item ) {
 830                         // This can only happen if $force is enabled.
 831                         return null;
 832                 }
 833
 834                 // Oldid given and isn't the latest; update the timestamp.
 835                 // This will result in no further notification emails being sent!
 836                 // Calls Revision::getTimestampFromId in normal operation
 837                 $notificationTimestamp = call_user_func(
 838                         $this->revisionGetTimestampFromIdCallback,
 839                         $title,
 840                         $oldid
 841                 );
 842
 843                 // We need to go one second to the future because of various strict comparisons
 844                 // throughout the codebase
 845                 $ts = new MWTimestamp( $notificationTimestamp );
 846                 $ts->timestamp->add( new DateInterval( 'PT1S' ) );
 847                 $notificationTimestamp = $ts->getTimestamp( TS_MW );
 848
 849                 if ( $notificationTimestamp < $item->getNotificationTimestamp() ) {
 850                         if ( $force != 'force' ) {
 851                                 return false;
 852                         } else {
 853                                 // This is a little silly…
 854                                 return $item->getNotificationTimestamp();
 855                         }
 856                 }
 857
 858                 return $notificationTimestamp;
 859         }
 860
 861         /**
 862          * @param User $user
 863          * @param int $unreadLimit
 864          *
 865          * @return int|bool The number of unread notifications
 866          *                  true if greater than or equal to $unreadLimit
 867          */
 868         public function countUnreadNotifications( User $user, $unreadLimit = null ) {
 869                 $queryOptions = [];
 870                 if ( $unreadLimit !== null ) {
 871                         $unreadLimit = (int)$unreadLimit;
 872                         $queryOptions['LIMIT'] = $unreadLimit;
 873                 }
 874
 875                 $dbr = $this->getConnection( DB_SLAVE );
 876                 $rowCount = $dbr->selectRowCount(
 877                         'watchlist',
 878                         '1',
 879                         [
 880                                 'wl_user' => $user->getId(),
 881                                 'wl_notificationtimestamp IS NOT NULL',
 882                         ],
 883                         __METHOD__,
 884                         $queryOptions
 885                 );
 886                 $this->reuseConnection( $dbr );
 887
 888                 if ( !isset( $unreadLimit ) ) {
 889                         return $rowCount;
 890                 }
 891
 892                 if ( $rowCount >= $unreadLimit ) {
 893                         return true;
 894                 }
 895
 896                 return $rowCount;
 897         }
 898
 899         /**
 900          * Check if the given title already is watched by the user, and if so
 901          * add a watch for the new title.
 902          *
 903          * To be used for page renames and such.
 904          *
 905          * @param LinkTarget $oldTarget
 906          * @param LinkTarget $newTarget
 907          */
 908         public function duplicateAllAssociatedEntries( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 909                 $oldTarget = Title::newFromLinkTarget( $oldTarget );
 910                 $newTarget = Title::newFromLinkTarget( $newTarget );
 911
 912                 $this->duplicateEntry( $oldTarget->getSubjectPage(), $newTarget->getSubjectPage() );
 913                 $this->duplicateEntry( $oldTarget->getTalkPage(), $newTarget->getTalkPage() );
 914         }
 915
 916         /**
 917          * Check if the given title already is watched by the user, and if so
 918          * add a watch for the new title.
 919          *
 920          * To be used for page renames and such.
 921          * This must be called separately for Subject and Talk pages
 922          *
 923          * @param LinkTarget $oldTarget
 924          * @param LinkTarget $newTarget
 925          */
 926         public function duplicateEntry( LinkTarget $oldTarget, LinkTarget $newTarget ) {
 927                 $dbw = $this->getConnection( DB_MASTER );
 928
 929                 $result = $dbw->select(
 930                         'watchlist',
 931                         [ 'wl_user', 'wl_notificationtimestamp' ],
 932                         [
 933                                 'wl_namespace' => $oldTarget->getNamespace(),
 934                                 'wl_title' => $oldTarget->getDBkey(),
 935                         ],
 936                         __METHOD__,
 937                         [ 'FOR UPDATE' ]
 938                 );
 939
 940                 $newNamespace = $newTarget->getNamespace();
 941                 $newDBkey = $newTarget->getDBkey();
 942
 943                 # Construct array to replace into the watchlist
 944                 $values = [];
 945                 foreach ( $result as $row ) {
 946                         $values[] = [
 947                                 'wl_user' => $row->wl_user,
 948                                 'wl_namespace' => $newNamespace,
 949                                 'wl_title' => $newDBkey,
 950                                 'wl_notificationtimestamp' => $row->wl_notificationtimestamp,
 951                         ];
 952                 }
 953
 954                 if ( !empty( $values ) ) {
 955                         # Perform replace
 956                         # Note that multi-row replace is very efficient for MySQL but may be inefficient for
 957                         # some other DBMSes, mostly due to poor simulation by us
 958                         $dbw->replace(
 959                                 'watchlist',
 960                                 [ [ 'wl_user', 'wl_namespace', 'wl_title' ] ],
 961                                 $values,
 962                                 __METHOD__
 963                         );
 964                 }
 965
 966                 $this->reuseConnection( $dbw );
 967         }
 968
 969 }