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