includes/WatchedItemStore.php

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