includes/LinksUpdate.php

   1 <?php
   2 /**
   3  * See docs/deferred.txt
   4  *
   5  * @todo document (e.g. one-sentence top-level class description).
   6  */
   7 class LinksUpdate {
   8
   9         /**@{{
  10          * @private
  11          */
  12         var $mId,            //!< Page ID of the article linked from
  13                 $mTitle,         //!< Title object of the article linked from
  14                 $mLinks,         //!< Map of title strings to IDs for the links in the document
  15                 $mImages,        //!< DB keys of the images used, in the array key only
  16                 $mTemplates,     //!< Map of title strings to IDs for the template references, including broken ones
  17                 $mExternals,     //!< URLs of external links, array key only
  18                 $mCategories,    //!< Map of category names to sort keys
  19                 $mInterlangs,    //!< Map of language codes to titles
  20                 $mProperties,    //!< Map of arbitrary name to value
  21                 $mDb,            //!< Database connection reference
  22                 $mOptions,       //!< SELECT options to be used (array)
  23                 $mRecursive;     //!< Whether to queue jobs for recursive updates
  24         /**@}}*/
  25
  26         /**
  27          * Constructor
  28          *
  29          * @param Title $title Title of the page we're updating
  30          * @param ParserOutput $parserOutput Output from a full parse of this page
  31          * @param bool $recursive Queue jobs for recursive updates?
  32          */
  33         function LinksUpdate( $title, $parserOutput, $recursive = true ) {
  34                 global $wgAntiLockFlags;
  35
  36                 if ( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) {
  37                         $this->mOptions = array();
  38                 } else {
  39                         $this->mOptions = array( 'FOR UPDATE' );
  40                 }
  41                 $this->mDb = wfGetDB( DB_MASTER );
  42
  43                 if ( !is_object( $title ) ) {
  44                         throw new MWException( "The calling convention to LinksUpdate::LinksUpdate() has changed. " .
  45                                 "Please see Article::editUpdates() for an invocation example.\n" );
  46                 }
  47                 $this->mTitle = $title;
  48                 $this->mId = $title->getArticleID();
  49
  50                 $this->mParserOutput = $parserOutput;
  51                 $this->mLinks = $parserOutput->getLinks();
  52                 $this->mImages = $parserOutput->getImages();
  53                 $this->mTemplates = $parserOutput->getTemplates();
  54                 $this->mExternals = $parserOutput->getExternalLinks();
  55                 $this->mCategories = $parserOutput->getCategories();
  56                 $this->mProperties = $parserOutput->getProperties();
  57
  58                 # Convert the format of the interlanguage links
  59                 # I didn't want to change it in the ParserOutput, because that array is passed all
  60                 # the way back to the skin, so either a skin API break would be required, or an
  61                 # inefficient back-conversion.
  62                 $ill = $parserOutput->getLanguageLinks();
  63                 $this->mInterlangs = array();
  64                 foreach ( $ill as $link ) {
  65                         list( $key, $title ) = explode( ':', $link, 2 );
  66                         $this->mInterlangs[$key] = $title;
  67                 }
  68
  69                 $this->mRecursive = $recursive;
  70
  71                 wfRunHooks( 'LinksUpdateConstructed', array( &$this ) );
  72         }
  73
  74         /**
  75          * Update link tables with outgoing links from an updated article
  76          */
  77         function doUpdate() {
  78                 global $wgUseDumbLinkUpdate;
  79
  80                 wfRunHooks( 'LinksUpdate', array( &$this ) );
  81                 if ( $wgUseDumbLinkUpdate ) {
  82                         $this->doDumbUpdate();
  83                 } else {
  84                         $this->doIncrementalUpdate();
  85                 }
  86                 wfRunHooks( 'LinksUpdateComplete', array( &$this ) );
  87
  88         }
  89
  90         protected function doIncrementalUpdate() {
  91                 wfProfileIn( __METHOD__ );
  92
  93                 # Page links
  94                 $existing = $this->getExistingLinks();
  95                 $this->incrTableUpdate( 'pagelinks', 'pl', $this->getLinkDeletions( $existing ),
  96                         $this->getLinkInsertions( $existing ) );
  97
  98                 # Image links
  99                 $existing = $this->getExistingImages();
 100
 101                 $imageDeletes = $this->getImageDeletions( $existing );
 102                 $this->incrTableUpdate( 'imagelinks', 'il', $imageDeletes, $this->getImageInsertions( $existing ) );
 103
 104                 # Invalidate all image description pages which had links added or removed
 105                 $imageUpdates = $imageDeletes + array_diff_key( $this->mImages, $existing );
 106                 $this->invalidateImageDescriptions( $imageUpdates );
 107
 108                 # External links
 109                 $existing = $this->getExistingExternals();
 110                 $this->incrTableUpdate( 'externallinks', 'el', $this->getExternalDeletions( $existing ),
 111                 $this->getExternalInsertions( $existing ) );
 112
 113                 # Language links
 114                 $existing = $this->getExistingInterlangs();
 115                 $this->incrTableUpdate( 'langlinks', 'll', $this->getInterlangDeletions( $existing ),
 116                         $this->getInterlangInsertions( $existing ) );
 117
 118                 # Template links
 119                 $existing = $this->getExistingTemplates();
 120                 $this->incrTableUpdate( 'templatelinks', 'tl', $this->getTemplateDeletions( $existing ),
 121                         $this->getTemplateInsertions( $existing ) );
 122
 123                 # Category links
 124                 $existing = $this->getExistingCategories();
 125
 126                 $categoryDeletes = $this->getCategoryDeletions( $existing );
 127
 128                 $this->incrTableUpdate( 'categorylinks', 'cl', $categoryDeletes, $this->getCategoryInsertions( $existing ) );
 129
 130                 # Invalidate all categories which were added, deleted or changed (set symmetric difference)
 131                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 132                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 133                 $this->invalidateCategories( $categoryUpdates );
 134                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 135
 136                 # Page properties
 137                 $existing = $this->getExistingProperties();
 138
 139                 $propertiesDeletes = $this->getPropertyDeletions( $existing );
 140
 141                 $this->incrTableUpdate( 'page_props', 'pp', $propertiesDeletes, $this->getPropertyInsertions( $existing ) );
 142
 143                 # Invalidate the necessary pages
 144                 $changed = $propertiesDeletes + array_diff_assoc( $this->mProperties, $existing );
 145                 $this->invalidateProperties( $changed );
 146
 147                 # Refresh links of all pages including this page
 148                 # This will be in a separate transaction
 149                 if ( $this->mRecursive ) {
 150                         $this->queueRecursiveJobs();
 151                 }
 152
 153                 wfProfileOut( __METHOD__ );
 154         }
 155
 156         /**
 157          * Link update which clears the previous entries and inserts new ones
 158          * May be slower or faster depending on level of lock contention and write speed of DB
 159          * Also useful where link table corruption needs to be repaired, e.g. in refreshLinks.php
 160          */
 161         protected function doDumbUpdate() {
 162                 wfProfileIn( __METHOD__ );
 163
 164                 # Refresh category pages and image description pages
 165                 $existing = $this->getExistingCategories();
 166                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 167                 $categoryDeletes = array_diff_assoc( $existing, $this->mCategories );
 168                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 169                 $existing = $this->getExistingImages();
 170                 $imageUpdates = array_diff_key( $existing, $this->mImages ) + array_diff_key( $this->mImages, $existing );
 171
 172                 $this->dumbTableUpdate( 'pagelinks',     $this->getLinkInsertions(),     'pl_from' );
 173                 $this->dumbTableUpdate( 'imagelinks',    $this->getImageInsertions(),    'il_from' );
 174                 $this->dumbTableUpdate( 'categorylinks', $this->getCategoryInsertions(), 'cl_from' );
 175                 $this->dumbTableUpdate( 'templatelinks', $this->getTemplateInsertions(), 'tl_from' );
 176                 $this->dumbTableUpdate( 'externallinks', $this->getExternalInsertions(), 'el_from' );
 177                 $this->dumbTableUpdate( 'langlinks',     $this->getInterlangInsertions(),'ll_from' );
 178                 $this->dumbTableUpdate( 'page_props',    $this->getPropertyInsertions(), 'pp_page' );
 179
 180                 # Update the cache of all the category pages and image description
 181                 # pages which were changed, and fix the category table count
 182                 $this->invalidateCategories( $categoryUpdates );
 183                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 184                 $this->invalidateImageDescriptions( $imageUpdates );
 185
 186                 # Refresh links of all pages including this page
 187                 # This will be in a separate transaction
 188                 if ( $this->mRecursive ) {
 189                         $this->queueRecursiveJobs();
 190                 }
 191
 192                 wfProfileOut( __METHOD__ );
 193         }
 194
 195         function queueRecursiveJobs() {
 196                 global $wgUpdateRowsPerJob;
 197                 wfProfileIn( __METHOD__ );
 198
 199                 $dbr = wfGetDB( DB_SLAVE );
 200                 $res = $dbr->select( 'templatelinks',
 201                         array( 'tl_from' ),
 202                         array(
 203                                 'tl_namespace' => $this->mTitle->getNamespace(),
 204                                 'tl_title' => $this->mTitle->getDBkey()
 205                         ), __METHOD__
 206                 );
 207
 208                 $numRows = $res->numRows();
 209                 $numBatches = ceil( $numRows / $wgUpdateRowsPerJob );
 210                 $realBatchSize = $numRows / $numBatches;
 211                 $start = false;
 212                 $jobs = array();
 213                 do {
 214                         for( $i = 0; $i <= $realBatchSize - 1; $i++ ) {
 215                                 $row = $res->fetchRow();
 216                                 if( $row ) {
 217                                         $id = $row[0];
 218                                 } else {
 219                                         $id = false;
 220                                         break;
 221                                 }
 222                         }
 223                         $params = array(
 224                                 'start' => $start,
 225                                 'end' => ( $id !== false ? $id - 1 : false ),
 226                         );
 227                         $jobs[] = new RefreshLinksJob2( $this->mTitle, $params );
 228
 229                         $start = $id;
 230                 } while ( $start );
 231
 232                 $dbr->freeResult( $res );
 233
 234                 Job::batchInsert( $jobs );
 235
 236                 wfProfileOut( __METHOD__ );
 237         }
 238
 239         /**
 240          * Invalidate the cache of a list of pages from a single namespace
 241          *
 242          * @param integer $namespace
 243          * @param array $dbkeys
 244          */
 245         function invalidatePages( $namespace, $dbkeys ) {
 246                 if ( !count( $dbkeys ) ) {
 247                         return;
 248                 }
 249
 250                 /**
 251                  * Determine which pages need to be updated
 252                  * This is necessary to prevent the job queue from smashing the DB with
 253                  * large numbers of concurrent invalidations of the same page
 254                  */
 255                 $now = $this->mDb->timestamp();
 256                 $ids = array();
 257                 $res = $this->mDb->select( 'page', array( 'page_id' ),
 258                         array(
 259                                 'page_namespace' => $namespace,
 260                                 'page_title IN (' . $this->mDb->makeList( $dbkeys ) . ')',
 261                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 262                         ), __METHOD__
 263                 );
 264                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 265                         $ids[] = $row->page_id;
 266                 }
 267                 if ( !count( $ids ) ) {
 268                         return;
 269                 }
 270
 271                 /**
 272                  * Do the update
 273                  * We still need the page_touched condition, in case the row has changed since
 274                  * the non-locking select above.
 275                  */
 276                 $this->mDb->update( 'page', array( 'page_touched' => $now ),
 277                         array(
 278                                 'page_id IN (' . $this->mDb->makeList( $ids ) . ')',
 279                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 280                         ), __METHOD__
 281                 );
 282         }
 283
 284         function invalidateCategories( $cats ) {
 285                 $this->invalidatePages( NS_CATEGORY, array_keys( $cats ) );
 286         }
 287
 288         /**
 289          * Update all the appropriate counts in the category table.
 290          * @param $added associative array of category name => sort key
 291          * @param $deleted associative array of category name => sort key
 292          */
 293         function updateCategoryCounts( $added, $deleted ) {
 294                 $a = new Article($this->mTitle);
 295                 $a->updateCategoryCounts(
 296                         array_keys( $added ), array_keys( $deleted )
 297                 );
 298         }
 299
 300         function invalidateImageDescriptions( $images ) {
 301                 $this->invalidatePages( NS_IMAGE, array_keys( $images ) );
 302         }
 303
 304         function dumbTableUpdate( $table, $insertions, $fromField ) {
 305                 $this->mDb->delete( $table, array( $fromField => $this->mId ), __METHOD__ );
 306                 if ( count( $insertions ) ) {
 307                         # The link array was constructed without FOR UPDATE, so there may
 308                         # be collisions.  This may cause minor link table inconsistencies,
 309                         # which is better than crippling the site with lock contention.
 310                         $this->mDb->insert( $table, $insertions, __METHOD__, array( 'IGNORE' ) );
 311                 }
 312         }
 313
 314         /**
 315          * Make a WHERE clause from a 2-d NS/dbkey array
 316          *
 317          * @param array $arr 2-d array indexed by namespace and DB key
 318          * @param string $prefix Field name prefix, without the underscore
 319          */
 320         function makeWhereFrom2d( &$arr, $prefix ) {
 321                 $lb = new LinkBatch;
 322                 $lb->setArray( $arr );
 323                 return $lb->constructSet( $prefix, $this->mDb );
 324         }
 325
 326         /**
 327          * Update a table by doing a delete query then an insert query
 328          * @private
 329          */
 330         function incrTableUpdate( $table, $prefix, $deletions, $insertions ) {
 331                 if ( $table == 'page_props' ) {
 332                         $fromField = 'pp_page';
 333                 } else {
 334                         $fromField = "{$prefix}_from";
 335                 }
 336                 $where = array( $fromField => $this->mId );
 337                 if ( $table == 'pagelinks' || $table == 'templatelinks' ) {
 338                         $clause = $this->makeWhereFrom2d( $deletions, $prefix );
 339                         if ( $clause ) {
 340                                 $where[] = $clause;
 341                         } else {
 342                                 $where = false;
 343                         }
 344                 } else {
 345                         if ( $table == 'langlinks' ) {
 346                                 $toField = 'll_lang';
 347                         } elseif ( $table == 'page_props' ) {
 348                                 $toField = 'pp_propname';
 349                         } else {
 350                                 $toField = $prefix . '_to';
 351                         }
 352                         if ( count( $deletions ) ) {
 353                                 $where[] = "$toField IN (" . $this->mDb->makeList( array_keys( $deletions ) ) . ')';
 354                         } else {
 355                                 $where = false;
 356                         }
 357                 }
 358                 if ( $where ) {
 359                         $this->mDb->delete( $table, $where, __METHOD__ );
 360                 }
 361                 if ( count( $insertions ) ) {
 362                         $this->mDb->insert( $table, $insertions, __METHOD__, 'IGNORE' );
 363                 }
 364         }
 365
 366
 367         /**
 368          * Get an array of pagelinks insertions for passing to the DB
 369          * Skips the titles specified by the 2-D array $existing
 370          * @private
 371          */
 372         function getLinkInsertions( $existing = array() ) {
 373                 $arr = array();
 374                 foreach( $this->mLinks as $ns => $dbkeys ) {
 375                         # array_diff_key() was introduced in PHP 5.1, there is a compatibility function
 376                         # in GlobalFunctions.php
 377                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 378                         foreach ( $diffs as $dbk => $id ) {
 379                                 $arr[] = array(
 380                                         'pl_from'      => $this->mId,
 381                                         'pl_namespace' => $ns,
 382                                         'pl_title'     => $dbk
 383                                 );
 384                         }
 385                 }
 386                 return $arr;
 387         }
 388
 389         /**
 390          * Get an array of template insertions. Like getLinkInsertions()
 391          * @private
 392          */
 393         function getTemplateInsertions( $existing = array() ) {
 394                 $arr = array();
 395                 foreach( $this->mTemplates as $ns => $dbkeys ) {
 396                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 397                         foreach ( $diffs as $dbk => $id ) {
 398                                 $arr[] = array(
 399                                         'tl_from'      => $this->mId,
 400                                         'tl_namespace' => $ns,
 401                                         'tl_title'     => $dbk
 402                                 );
 403                         }
 404                 }
 405                 return $arr;
 406         }
 407
 408         /**
 409          * Get an array of image insertions
 410          * Skips the names specified in $existing
 411          * @private
 412          */
 413         function getImageInsertions( $existing = array() ) {
 414                 $arr = array();
 415                 $diffs = array_diff_key( $this->mImages, $existing );
 416                 foreach( $diffs as $iname => $dummy ) {
 417                         $arr[] = array(
 418                                 'il_from' => $this->mId,
 419                                 'il_to'   => $iname
 420                         );
 421                 }
 422                 return $arr;
 423         }
 424
 425         /**
 426          * Get an array of externallinks insertions. Skips the names specified in $existing
 427          * @private
 428          */
 429         function getExternalInsertions( $existing = array() ) {
 430                 $arr = array();
 431                 $diffs = array_diff_key( $this->mExternals, $existing );
 432                 foreach( $diffs as $url => $dummy ) {
 433                         $arr[] = array(
 434                                 'el_from'   => $this->mId,
 435                                 'el_to'     => $url,
 436                                 'el_index'  => wfMakeUrlIndex( $url ),
 437                         );
 438                 }
 439                 return $arr;
 440         }
 441
 442         /**
 443          * Get an array of category insertions
 444          * @param array $existing Array mapping existing category names to sort keys. If both
 445          * match a link in $this, the link will be omitted from the output
 446          * @private
 447          */
 448         function getCategoryInsertions( $existing = array() ) {
 449                 $diffs = array_diff_assoc( $this->mCategories, $existing );
 450                 $arr = array();
 451                 foreach ( $diffs as $name => $sortkey ) {
 452                         $arr[] = array(
 453                                 'cl_from'    => $this->mId,
 454                                 'cl_to'      => $name,
 455                                 'cl_sortkey' => $sortkey,
 456                                 'cl_timestamp' => $this->mDb->timestamp()
 457                         );
 458                 }
 459                 return $arr;
 460         }
 461
 462         /**
 463          * Get an array of interlanguage link insertions
 464          * @param array $existing Array mapping existing language codes to titles
 465          * @private
 466          */
 467         function getInterlangInsertions( $existing = array() ) {
 468             $diffs = array_diff_assoc( $this->mInterlangs, $existing );
 469             $arr = array();
 470             foreach( $diffs as $lang => $title ) {
 471                 $arr[] = array(
 472                     'll_from'  => $this->mId,
 473                     'll_lang'  => $lang,
 474                     'll_title' => $title
 475                 );
 476             }
 477             return $arr;
 478         }
 479
 480         /**
 481          * Get an array of page property insertions
 482          */
 483         function getPropertyInsertions( $existing = array() ) {
 484                 $diffs = array_diff_assoc( $this->mProperties, $existing );
 485                 $arr = array();
 486                 foreach ( $diffs as $name => $value ) {
 487                         $arr[] = array(
 488                                 'pp_page'      => $this->mId,
 489                                 'pp_propname'  => $name,
 490                                 'pp_value'     => $value,
 491                         );
 492                 }
 493                 return $arr;
 494         }
 495
 496
 497         /**
 498          * Given an array of existing links, returns those links which are not in $this
 499          * and thus should be deleted.
 500          * @private
 501          */
 502         function getLinkDeletions( $existing ) {
 503                 $del = array();
 504                 foreach ( $existing as $ns => $dbkeys ) {
 505                         if ( isset( $this->mLinks[$ns] ) ) {
 506                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mLinks[$ns] );
 507                         } else {
 508                                 $del[$ns] = $existing[$ns];
 509                         }
 510                 }
 511                 return $del;
 512         }
 513
 514         /**
 515          * Given an array of existing templates, returns those templates which are not in $this
 516          * and thus should be deleted.
 517          * @private
 518          */
 519         function getTemplateDeletions( $existing ) {
 520                 $del = array();
 521                 foreach ( $existing as $ns => $dbkeys ) {
 522                         if ( isset( $this->mTemplates[$ns] ) ) {
 523                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mTemplates[$ns] );
 524                         } else {
 525                                 $del[$ns] = $existing[$ns];
 526                         }
 527                 }
 528                 return $del;
 529         }
 530
 531         /**
 532          * Given an array of existing images, returns those images which are not in $this
 533          * and thus should be deleted.
 534          * @private
 535          */
 536         function getImageDeletions( $existing ) {
 537                 return array_diff_key( $existing, $this->mImages );
 538         }
 539
 540         /**
 541          * Given an array of existing external links, returns those links which are not
 542          * in $this and thus should be deleted.
 543          * @private
 544          */
 545         function getExternalDeletions( $existing ) {
 546                 return array_diff_key( $existing, $this->mExternals );
 547         }
 548
 549         /**
 550          * Given an array of existing categories, returns those categories which are not in $this
 551          * and thus should be deleted.
 552          * @private
 553          */
 554         function getCategoryDeletions( $existing ) {
 555                 return array_diff_assoc( $existing, $this->mCategories );
 556         }
 557
 558         /**
 559          * Given an array of existing interlanguage links, returns those links which are not
 560          * in $this and thus should be deleted.
 561          * @private
 562          */
 563         function getInterlangDeletions( $existing ) {
 564             return array_diff_assoc( $existing, $this->mInterlangs );
 565         }
 566
 567         /**
 568          * Get array of properties which should be deleted.
 569          * @private
 570          */
 571         function getPropertyDeletions( $existing ) {
 572                 return array_diff_assoc( $existing, $this->mProperties );
 573         }
 574
 575         /**
 576          * Get an array of existing links, as a 2-D array
 577          * @private
 578          */
 579         function getExistingLinks() {
 580                 $res = $this->mDb->select( 'pagelinks', array( 'pl_namespace', 'pl_title' ),
 581                         array( 'pl_from' => $this->mId ), __METHOD__, $this->mOptions );
 582                 $arr = array();
 583                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 584                         if ( !isset( $arr[$row->pl_namespace] ) ) {
 585                                 $arr[$row->pl_namespace] = array();
 586                         }
 587                         $arr[$row->pl_namespace][$row->pl_title] = 1;
 588                 }
 589                 $this->mDb->freeResult( $res );
 590                 return $arr;
 591         }
 592
 593         /**
 594          * Get an array of existing templates, as a 2-D array
 595          * @private
 596          */
 597         function getExistingTemplates() {
 598                 $res = $this->mDb->select( 'templatelinks', array( 'tl_namespace', 'tl_title' ),
 599                         array( 'tl_from' => $this->mId ), __METHOD__, $this->mOptions );
 600                 $arr = array();
 601                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 602                         if ( !isset( $arr[$row->tl_namespace] ) ) {
 603                                 $arr[$row->tl_namespace] = array();
 604                         }
 605                         $arr[$row->tl_namespace][$row->tl_title] = 1;
 606                 }
 607                 $this->mDb->freeResult( $res );
 608                 return $arr;
 609         }
 610
 611         /**
 612          * Get an array of existing images, image names in the keys
 613          * @private
 614          */
 615         function getExistingImages() {
 616                 $res = $this->mDb->select( 'imagelinks', array( 'il_to' ),
 617                         array( 'il_from' => $this->mId ), __METHOD__, $this->mOptions );
 618                 $arr = array();
 619                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 620                         $arr[$row->il_to] = 1;
 621                 }
 622                 $this->mDb->freeResult( $res );
 623                 return $arr;
 624         }
 625
 626         /**
 627          * Get an array of existing external links, URLs in the keys
 628          * @private
 629          */
 630         function getExistingExternals() {
 631                 $res = $this->mDb->select( 'externallinks', array( 'el_to' ),
 632                         array( 'el_from' => $this->mId ), __METHOD__, $this->mOptions );
 633                 $arr = array();
 634                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 635                         $arr[$row->el_to] = 1;
 636                 }
 637                 $this->mDb->freeResult( $res );
 638                 return $arr;
 639         }
 640
 641         /**
 642          * Get an array of existing categories, with the name in the key and sort key in the value.
 643          * @private
 644          */
 645         function getExistingCategories() {
 646                 $res = $this->mDb->select( 'categorylinks', array( 'cl_to', 'cl_sortkey' ),
 647                         array( 'cl_from' => $this->mId ), __METHOD__, $this->mOptions );
 648                 $arr = array();
 649                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 650                         $arr[$row->cl_to] = $row->cl_sortkey;
 651                 }
 652                 $this->mDb->freeResult( $res );
 653                 return $arr;
 654         }
 655
 656         /**
 657          * Get an array of existing interlanguage links, with the language code in the key and the
 658          * title in the value.
 659          * @private
 660          */
 661         function getExistingInterlangs() {
 662                 $res = $this->mDb->select( 'langlinks', array( 'll_lang', 'll_title' ),
 663                         array( 'll_from' => $this->mId ), __METHOD__, $this->mOptions );
 664                 $arr = array();
 665                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 666                         $arr[$row->ll_lang] = $row->ll_title;
 667                 }
 668                 return $arr;
 669         }
 670
 671         /**
 672          * Get an array of existing categories, with the name in the key and sort key in the value.
 673          * @private
 674          */
 675         function getExistingProperties() {
 676                 $res = $this->mDb->select( 'page_props', array( 'pp_propname', 'pp_value' ),
 677                         array( 'pp_page' => $this->mId ), __METHOD__, $this->mOptions );
 678                 $arr = array();
 679                 while ( $row = $this->mDb->fetchObject( $res ) ) {
 680                         $arr[$row->pp_propname] = $row->pp_value;
 681                 }
 682                 $this->mDb->freeResult( $res );
 683                 return $arr;
 684         }
 685
 686
 687         /**
 688          * Return the title object of the page being updated
 689          */
 690         function getTitle() {
 691                 return $this->mTitle;
 692         }
 693
 694         /**
 695          * Invalidate any necessary link lists related to page property changes
 696          */
 697         function invalidateProperties( $changed ) {
 698                 global $wgPagePropLinkInvalidations;
 699
 700                 foreach ( $changed as $name => $value ) {
 701                         if ( isset( $wgPagePropLinkInvalidations[$name] ) ) {
 702                                 $inv = $wgPagePropLinkInvalidations[$name];
 703                                 if ( !is_array( $inv ) ) {
 704                                         $inv = array( $inv );
 705                                 }
 706                                 foreach ( $inv as $table ) {
 707                                         $update = new HTMLCacheUpdate( $this->mTitle, $table );
 708                                         $update->doUpdate();
 709                                 }
 710                         }
 711                 }
 712         }
 713 }