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 of the page we're updating
  30          * @param $parserOutput ParserOutput: output from a full parse of this page
  31          * @param $recursive Boolean: queue jobs for recursive updates?
  32          */
  33         function __construct( $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                 $this->mInterwikis = $parserOutput->getInterwikiLinks();
  58
  59                 # Convert the format of the interlanguage links
  60                 # I didn't want to change it in the ParserOutput, because that array is passed all
  61                 # the way back to the skin, so either a skin API break would be required, or an
  62                 # inefficient back-conversion.
  63                 $ill = $parserOutput->getLanguageLinks();
  64                 $this->mInterlangs = array();
  65                 foreach ( $ill as $link ) {
  66                         list( $key, $title ) = explode( ':', $link, 2 );
  67                         $this->mInterlangs[$key] = $title;
  68                 }
  69
  70                 foreach ( $this->mCategories as &$sortkey ) {
  71                         # If the sortkey is longer then 255 bytes,
  72                         # it truncated by DB, and then doesn't get
  73                         # matched when comparing existing vs current
  74                         # categories, causing bug 25254.
  75                         # Also. substr behaves weird when given "".
  76                         if ( $sortkey !== '' ) {
  77                                 $sortkey = substr( $sortkey, 0, 255 );
  78                         }
  79                 }
  80
  81                 $this->mRecursive = $recursive;
  82
  83                 wfRunHooks( 'LinksUpdateConstructed', array( &$this ) );
  84         }
  85
  86         /**
  87          * Update link tables with outgoing links from an updated article
  88          */
  89         public function doUpdate() {
  90                 global $wgUseDumbLinkUpdate;
  91
  92                 wfRunHooks( 'LinksUpdate', array( &$this ) );
  93                 if ( $wgUseDumbLinkUpdate ) {
  94                         $this->doDumbUpdate();
  95                 } else {
  96                         $this->doIncrementalUpdate();
  97                 }
  98                 wfRunHooks( 'LinksUpdateComplete', array( &$this ) );
  99         }
 100
 101         protected function doIncrementalUpdate() {
 102                 wfProfileIn( __METHOD__ );
 103
 104                 # Page links
 105                 $existing = $this->getExistingLinks();
 106                 $this->incrTableUpdate( 'pagelinks', 'pl', $this->getLinkDeletions( $existing ),
 107                         $this->getLinkInsertions( $existing ) );
 108
 109                 # Image links
 110                 $existing = $this->getExistingImages();
 111
 112                 $imageDeletes = $this->getImageDeletions( $existing );
 113                 $this->incrTableUpdate( 'imagelinks', 'il', $imageDeletes, $this->getImageInsertions( $existing ) );
 114
 115                 # Invalidate all image description pages which had links added or removed
 116                 $imageUpdates = $imageDeletes + array_diff_key( $this->mImages, $existing );
 117                 $this->invalidateImageDescriptions( $imageUpdates );
 118
 119                 # External links
 120                 $existing = $this->getExistingExternals();
 121                 $this->incrTableUpdate( 'externallinks', 'el', $this->getExternalDeletions( $existing ),
 122                 $this->getExternalInsertions( $existing ) );
 123
 124                 # Language links
 125                 $existing = $this->getExistingInterlangs();
 126                 $this->incrTableUpdate( 'langlinks', 'll', $this->getInterlangDeletions( $existing ),
 127                         $this->getInterlangInsertions( $existing ) );
 128
 129                 # Inline interwiki links
 130                 $existing = $this->getExistingInterwikis();
 131                 $this->incrTableUpdate( 'iwlinks', 'iwl', $this->getInterwikiDeletions( $existing ),
 132                         $this->getInterwikiInsertions( $existing ) );
 133
 134                 # Template links
 135                 $existing = $this->getExistingTemplates();
 136                 $this->incrTableUpdate( 'templatelinks', 'tl', $this->getTemplateDeletions( $existing ),
 137                         $this->getTemplateInsertions( $existing ) );
 138
 139                 # Category links
 140                 $existing = $this->getExistingCategories();
 141
 142                 $categoryDeletes = $this->getCategoryDeletions( $existing );
 143
 144                 $this->incrTableUpdate( 'categorylinks', 'cl', $categoryDeletes, $this->getCategoryInsertions( $existing ) );
 145
 146                 # Invalidate all categories which were added, deleted or changed (set symmetric difference)
 147                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 148                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 149                 $this->invalidateCategories( $categoryUpdates );
 150                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 151
 152                 # Page properties
 153                 $existing = $this->getExistingProperties();
 154
 155                 $propertiesDeletes = $this->getPropertyDeletions( $existing );
 156
 157                 $this->incrTableUpdate( 'page_props', 'pp', $propertiesDeletes, $this->getPropertyInsertions( $existing ) );
 158
 159                 # Invalidate the necessary pages
 160                 $changed = $propertiesDeletes + array_diff_assoc( $this->mProperties, $existing );
 161                 $this->invalidateProperties( $changed );
 162
 163                 # Refresh links of all pages including this page
 164                 # This will be in a separate transaction
 165                 if ( $this->mRecursive ) {
 166                         $this->queueRecursiveJobs();
 167                 }
 168
 169                 wfProfileOut( __METHOD__ );
 170         }
 171
 172         /**
 173          * Link update which clears the previous entries and inserts new ones
 174          * May be slower or faster depending on level of lock contention and write speed of DB
 175          * Also useful where link table corruption needs to be repaired, e.g. in refreshLinks.php
 176          */
 177         protected function doDumbUpdate() {
 178                 wfProfileIn( __METHOD__ );
 179
 180                 # Refresh category pages and image description pages
 181                 $existing = $this->getExistingCategories();
 182                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 183                 $categoryDeletes = array_diff_assoc( $existing, $this->mCategories );
 184                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 185                 $existing = $this->getExistingImages();
 186                 $imageUpdates = array_diff_key( $existing, $this->mImages ) + array_diff_key( $this->mImages, $existing );
 187
 188                 $this->dumbTableUpdate( 'pagelinks',     $this->getLinkInsertions(),     'pl_from' );
 189                 $this->dumbTableUpdate( 'imagelinks',    $this->getImageInsertions(),    'il_from' );
 190                 $this->dumbTableUpdate( 'categorylinks', $this->getCategoryInsertions(), 'cl_from' );
 191                 $this->dumbTableUpdate( 'templatelinks', $this->getTemplateInsertions(), 'tl_from' );
 192                 $this->dumbTableUpdate( 'externallinks', $this->getExternalInsertions(), 'el_from' );
 193                 $this->dumbTableUpdate( 'langlinks',     $this->getInterlangInsertions(),'ll_from' );
 194                 $this->dumbTableUpdate( 'iwlinks',       $this->getInterwikiInsertions(),'iwl_from' );
 195                 $this->dumbTableUpdate( 'page_props',    $this->getPropertyInsertions(), 'pp_page' );
 196
 197                 # Update the cache of all the category pages and image description
 198                 # pages which were changed, and fix the category table count
 199                 $this->invalidateCategories( $categoryUpdates );
 200                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 201                 $this->invalidateImageDescriptions( $imageUpdates );
 202
 203                 # Refresh links of all pages including this page
 204                 # This will be in a separate transaction
 205                 if ( $this->mRecursive ) {
 206                         $this->queueRecursiveJobs();
 207                 }
 208
 209                 wfProfileOut( __METHOD__ );
 210         }
 211
 212         function queueRecursiveJobs() {
 213                 global $wgUpdateRowsPerJob;
 214                 wfProfileIn( __METHOD__ );
 215
 216                 $cache = $this->mTitle->getBacklinkCache();
 217                 $batches = $cache->partition( 'templatelinks', $wgUpdateRowsPerJob );
 218                 if ( !$batches ) {
 219                         wfProfileOut( __METHOD__ );
 220                         return;
 221                 }
 222                 $jobs = array();
 223                 foreach ( $batches as $batch ) {
 224                         list( $start, $end ) = $batch;
 225                         $params = array(
 226                                 'start' => $start,
 227                                 'end' => $end,
 228                         );
 229                         $jobs[] = new RefreshLinksJob2( $this->mTitle, $params );
 230                 }
 231                 Job::batchInsert( $jobs );
 232
 233                 wfProfileOut( __METHOD__ );
 234         }
 235
 236         /**
 237          * Invalidate the cache of a list of pages from a single namespace
 238          *
 239          * @param $namespace Integer
 240          * @param $dbkeys Array
 241          */
 242         function invalidatePages( $namespace, $dbkeys ) {
 243                 if ( !count( $dbkeys ) ) {
 244                         return;
 245                 }
 246
 247                 /**
 248                  * Determine which pages need to be updated
 249                  * This is necessary to prevent the job queue from smashing the DB with
 250                  * large numbers of concurrent invalidations of the same page
 251                  */
 252                 $now = $this->mDb->timestamp();
 253                 $ids = array();
 254                 $res = $this->mDb->select( 'page', array( 'page_id' ),
 255                         array(
 256                                 'page_namespace' => $namespace,
 257                                 'page_title IN (' . $this->mDb->makeList( $dbkeys ) . ')',
 258                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 259                         ), __METHOD__
 260                 );
 261                 foreach ( $res as $row ) {
 262                         $ids[] = $row->page_id;
 263                 }
 264                 if ( !count( $ids ) ) {
 265                         return;
 266                 }
 267
 268                 /**
 269                  * Do the update
 270                  * We still need the page_touched condition, in case the row has changed since
 271                  * the non-locking select above.
 272                  */
 273                 $this->mDb->update( 'page', array( 'page_touched' => $now ),
 274                         array(
 275                                 'page_id IN (' . $this->mDb->makeList( $ids ) . ')',
 276                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 277                         ), __METHOD__
 278                 );
 279         }
 280
 281         function invalidateCategories( $cats ) {
 282                 $this->invalidatePages( NS_CATEGORY, array_keys( $cats ) );
 283         }
 284
 285         /**
 286          * Update all the appropriate counts in the category table.
 287          * @param $added associative array of category name => sort key
 288          * @param $deleted associative array of category name => sort key
 289          */
 290         function updateCategoryCounts( $added, $deleted ) {
 291                 $a = new Article($this->mTitle);
 292                 $a->updateCategoryCounts(
 293                         array_keys( $added ), array_keys( $deleted )
 294                 );
 295         }
 296
 297         function invalidateImageDescriptions( $images ) {
 298                 $this->invalidatePages( NS_FILE, array_keys( $images ) );
 299         }
 300
 301         function dumbTableUpdate( $table, $insertions, $fromField ) {
 302                 $this->mDb->delete( $table, array( $fromField => $this->mId ), __METHOD__ );
 303                 if ( count( $insertions ) ) {
 304                         # The link array was constructed without FOR UPDATE, so there may
 305                         # be collisions.  This may cause minor link table inconsistencies,
 306                         # which is better than crippling the site with lock contention.
 307                         $this->mDb->insert( $table, $insertions, __METHOD__, array( 'IGNORE' ) );
 308                 }
 309         }
 310
 311         /**
 312          * Update a table by doing a delete query then an insert query
 313          * @private
 314          */
 315         function incrTableUpdate( $table, $prefix, $deletions, $insertions ) {
 316                 if ( $table == 'page_props' ) {
 317                         $fromField = 'pp_page';
 318                 } else {
 319                         $fromField = "{$prefix}_from";
 320                 }
 321                 $where = array( $fromField => $this->mId );
 322                 if ( $table == 'pagelinks' || $table == 'templatelinks' || $table == 'iwlinks' ) {
 323                         if ( $table == 'iwlinks' ) {
 324                                 $baseKey = 'iwl_prefix';
 325                         } else {
 326                                 $baseKey = "{$prefix}_namespace";
 327                         }
 328                         $clause = $this->mDb->makeWhereFrom2d( $deletions, $baseKey, "{$prefix}_title" );
 329                         if ( $clause ) {
 330                                 $where[] = $clause;
 331                         } else {
 332                                 $where = false;
 333                         }
 334                 } else {
 335                         if ( $table == 'langlinks' ) {
 336                                 $toField = 'll_lang';
 337                         } elseif ( $table == 'page_props' ) {
 338                                 $toField = 'pp_propname';
 339                         } else {
 340                                 $toField = $prefix . '_to';
 341                         }
 342                         if ( count( $deletions ) ) {
 343                                 $where[] = "$toField IN (" . $this->mDb->makeList( array_keys( $deletions ) ) . ')';
 344                         } else {
 345                                 $where = false;
 346                         }
 347                 }
 348
 349                 // Create and use a new loadBalancer object, to prevent "1205: Lock wait timeout exceeded;"
 350                 $lb = wfGetLBFactory()->newMainLB();
 351                 $dbw = $lb->getConnection( DB_MASTER );
 352
 353                 if ( $where ) {
 354                         $dbw->delete( $table, $where, __METHOD__ );
 355                 }
 356                 if ( count( $insertions ) ) {
 357                         $dbw->insert( $table, $insertions, __METHOD__, 'IGNORE' );
 358                 }
 359
 360                 $lb->commitMasterChanges();
 361                 $lb->closeAll();
 362         }
 363
 364         /**
 365          * Get an array of pagelinks insertions for passing to the DB
 366          * Skips the titles specified by the 2-D array $existing
 367          * @private
 368          */
 369         function getLinkInsertions( $existing = array() ) {
 370                 $arr = array();
 371                 foreach( $this->mLinks as $ns => $dbkeys ) {
 372                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 373                         foreach ( $diffs as $dbk => $id ) {
 374                                 $arr[] = array(
 375                                         'pl_from'      => $this->mId,
 376                                         'pl_namespace' => $ns,
 377                                         'pl_title'     => $dbk
 378                                 );
 379                         }
 380                 }
 381                 return $arr;
 382         }
 383
 384         /**
 385          * Get an array of template insertions. Like getLinkInsertions()
 386          * @private
 387          */
 388         function getTemplateInsertions( $existing = array() ) {
 389                 $arr = array();
 390                 foreach( $this->mTemplates as $ns => $dbkeys ) {
 391                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 392                         foreach ( $diffs as $dbk => $id ) {
 393                                 $arr[] = array(
 394                                         'tl_from'      => $this->mId,
 395                                         'tl_namespace' => $ns,
 396                                         'tl_title'     => $dbk
 397                                 );
 398                         }
 399                 }
 400                 return $arr;
 401         }
 402
 403         /**
 404          * Get an array of image insertions
 405          * Skips the names specified in $existing
 406          * @private
 407          */
 408         function getImageInsertions( $existing = array() ) {
 409                 $arr = array();
 410                 $diffs = array_diff_key( $this->mImages, $existing );
 411                 foreach( $diffs as $iname => $dummy ) {
 412                         $arr[] = array(
 413                                 'il_from' => $this->mId,
 414                                 'il_to'   => $iname
 415                         );
 416                 }
 417                 return $arr;
 418         }
 419
 420         /**
 421          * Get an array of externallinks insertions. Skips the names specified in $existing
 422          * @private
 423          */
 424         function getExternalInsertions( $existing = array() ) {
 425                 $arr = array();
 426                 $diffs = array_diff_key( $this->mExternals, $existing );
 427                 foreach( $diffs as $url => $dummy ) {
 428                         $arr[] = array(
 429                                 'el_from'   => $this->mId,
 430                                 'el_to'     => $url,
 431                                 'el_index'  => wfMakeUrlIndex( $url ),
 432                         );
 433                 }
 434                 return $arr;
 435         }
 436
 437         /**
 438          * Get an array of category insertions
 439          *
 440          * @param $existing Array mapping existing category names to sort keys. If both
 441          * match a link in $this, the link will be omitted from the output
 442          * @private
 443          */
 444         function getCategoryInsertions( $existing = array() ) {
 445                 global $wgContLang, $wgCategoryCollation;
 446                 $diffs = array_diff_assoc( $this->mCategories, $existing );
 447                 $arr = array();
 448                 foreach ( $diffs as $name => $prefix ) {
 449                         $nt = Title::makeTitleSafe( NS_CATEGORY, $name );
 450                         $wgContLang->findVariantLink( $name, $nt, true );
 451
 452                         if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
 453                                 $type = 'subcat';
 454                         } elseif ( $this->mTitle->getNamespace() == NS_FILE ) {
 455                                 $type = 'file';
 456                         } else {
 457                                 $type = 'page';
 458                         }
 459
 460                         # Treat custom sortkeys as a prefix, so that if multiple
 461                         # things are forced to sort as '*' or something, they'll
 462                         # sort properly in the category rather than in page_id
 463                         # order or such.
 464                         $sortkey = Collation::singleton()->getSortKey(
 465                                 $this->mTitle->getCategorySortkey( $prefix ) );
 466
 467                         $arr[] = array(
 468                                 'cl_from'    => $this->mId,
 469                                 'cl_to'      => $name,
 470                                 'cl_sortkey' => $sortkey,
 471                                 'cl_timestamp' => $this->mDb->timestamp(),
 472                                 'cl_sortkey_prefix' => $prefix,
 473                                 'cl_collation' => $wgCategoryCollation,
 474                                 'cl_type' => $type,
 475                         );
 476                 }
 477                 return $arr;
 478         }
 479
 480         /**
 481          * Get an array of interlanguage link insertions
 482          *
 483          * @param $existing Array mapping existing language codes to titles
 484          * @private
 485          */
 486         function getInterlangInsertions( $existing = array() ) {
 487             $diffs = array_diff_assoc( $this->mInterlangs, $existing );
 488             $arr = array();
 489             foreach( $diffs as $lang => $title ) {
 490                 $arr[] = array(
 491                     'll_from'  => $this->mId,
 492                     'll_lang'  => $lang,
 493                     'll_title' => $title
 494                 );
 495             }
 496             return $arr;
 497         }
 498
 499         /**
 500          * Get an array of page property insertions
 501          */
 502         function getPropertyInsertions( $existing = array() ) {
 503                 $diffs = array_diff_assoc( $this->mProperties, $existing );
 504                 $arr = array();
 505                 foreach ( $diffs as $name => $value ) {
 506                         $arr[] = array(
 507                                 'pp_page'      => $this->mId,
 508                                 'pp_propname'  => $name,
 509                                 'pp_value'     => $value,
 510                         );
 511                 }
 512                 return $arr;
 513         }
 514
 515         /**
 516          * Get an array of interwiki insertions for passing to the DB
 517          * Skips the titles specified by the 2-D array $existing
 518          * @private
 519          */
 520         function getInterwikiInsertions( $existing = array() ) {
 521                 $arr = array();
 522                 foreach( $this->mInterwikis as $prefix => $dbkeys ) {
 523                         $diffs = isset( $existing[$prefix] ) ? array_diff_key( $dbkeys, $existing[$prefix] ) : $dbkeys;
 524                         foreach ( $diffs as $dbk => $id ) {
 525                                 $arr[] = array(
 526                                         'iwl_from'   => $this->mId,
 527                                         'iwl_prefix' => $prefix,
 528                                         'iwl_title'  => $dbk
 529                                 );
 530                         }
 531                 }
 532                 return $arr;
 533         }
 534
 535         /**
 536          * Given an array of existing links, returns those links which are not in $this
 537          * and thus should be deleted.
 538          * @private
 539          */
 540         function getLinkDeletions( $existing ) {
 541                 $del = array();
 542                 foreach ( $existing as $ns => $dbkeys ) {
 543                         if ( isset( $this->mLinks[$ns] ) ) {
 544                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mLinks[$ns] );
 545                         } else {
 546                                 $del[$ns] = $existing[$ns];
 547                         }
 548                 }
 549                 return $del;
 550         }
 551
 552         /**
 553          * Given an array of existing templates, returns those templates which are not in $this
 554          * and thus should be deleted.
 555          * @private
 556          */
 557         function getTemplateDeletions( $existing ) {
 558                 $del = array();
 559                 foreach ( $existing as $ns => $dbkeys ) {
 560                         if ( isset( $this->mTemplates[$ns] ) ) {
 561                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mTemplates[$ns] );
 562                         } else {
 563                                 $del[$ns] = $existing[$ns];
 564                         }
 565                 }
 566                 return $del;
 567         }
 568
 569         /**
 570          * Given an array of existing images, returns those images which are not in $this
 571          * and thus should be deleted.
 572          * @private
 573          */
 574         function getImageDeletions( $existing ) {
 575                 return array_diff_key( $existing, $this->mImages );
 576         }
 577
 578         /**
 579          * Given an array of existing external links, returns those links which are not
 580          * in $this and thus should be deleted.
 581          * @private
 582          */
 583         function getExternalDeletions( $existing ) {
 584                 return array_diff_key( $existing, $this->mExternals );
 585         }
 586
 587         /**
 588          * Given an array of existing categories, returns those categories which are not in $this
 589          * and thus should be deleted.
 590          * @private
 591          */
 592         function getCategoryDeletions( $existing ) {
 593                 return array_diff_assoc( $existing, $this->mCategories );
 594         }
 595
 596         /**
 597          * Given an array of existing interlanguage links, returns those links which are not
 598          * in $this and thus should be deleted.
 599          * @private
 600          */
 601         function getInterlangDeletions( $existing ) {
 602             return array_diff_assoc( $existing, $this->mInterlangs );
 603         }
 604
 605         /**
 606          * Get array of properties which should be deleted.
 607          * @private
 608          */
 609         function getPropertyDeletions( $existing ) {
 610                 return array_diff_assoc( $existing, $this->mProperties );
 611         }
 612
 613         /**
 614          * Given an array of existing interwiki links, returns those links which are not in $this
 615          * and thus should be deleted.
 616          * @private
 617          */
 618         function getInterwikiDeletions( $existing ) {
 619                 $del = array();
 620                 foreach ( $existing as $prefix => $dbkeys ) {
 621                         if ( isset( $this->mInterwikis[$prefix] ) ) {
 622                                 $del[$prefix] = array_diff_key( $existing[$prefix], $this->mInterwikis[$prefix] );
 623                         } else {
 624                                 $del[$prefix] = $existing[$prefix];
 625                         }
 626                 }
 627                 return $del;
 628         }
 629
 630         /**
 631          * Get an array of existing links, as a 2-D array
 632          * @private
 633          */
 634         function getExistingLinks() {
 635                 $res = $this->mDb->select( 'pagelinks', array( 'pl_namespace', 'pl_title' ),
 636                         array( 'pl_from' => $this->mId ), __METHOD__, $this->mOptions );
 637                 $arr = array();
 638                 foreach ( $res as $row ) {
 639                         if ( !isset( $arr[$row->pl_namespace] ) ) {
 640                                 $arr[$row->pl_namespace] = array();
 641                         }
 642                         $arr[$row->pl_namespace][$row->pl_title] = 1;
 643                 }
 644                 return $arr;
 645         }
 646
 647         /**
 648          * Get an array of existing templates, as a 2-D array
 649          * @private
 650          */
 651         function getExistingTemplates() {
 652                 $res = $this->mDb->select( 'templatelinks', array( 'tl_namespace', 'tl_title' ),
 653                         array( 'tl_from' => $this->mId ), __METHOD__, $this->mOptions );
 654                 $arr = array();
 655                 foreach ( $res as $row ) {
 656                         if ( !isset( $arr[$row->tl_namespace] ) ) {
 657                                 $arr[$row->tl_namespace] = array();
 658                         }
 659                         $arr[$row->tl_namespace][$row->tl_title] = 1;
 660                 }
 661                 return $arr;
 662         }
 663
 664         /**
 665          * Get an array of existing images, image names in the keys
 666          * @private
 667          */
 668         function getExistingImages() {
 669                 $res = $this->mDb->select( 'imagelinks', array( 'il_to' ),
 670                         array( 'il_from' => $this->mId ), __METHOD__, $this->mOptions );
 671                 $arr = array();
 672                 foreach ( $res as $row ) {
 673                         $arr[$row->il_to] = 1;
 674                 }
 675                 return $arr;
 676         }
 677
 678         /**
 679          * Get an array of existing external links, URLs in the keys
 680          * @private
 681          */
 682         function getExistingExternals() {
 683                 $res = $this->mDb->select( 'externallinks', array( 'el_to' ),
 684                         array( 'el_from' => $this->mId ), __METHOD__, $this->mOptions );
 685                 $arr = array();
 686                 foreach ( $res as $row ) {
 687                         $arr[$row->el_to] = 1;
 688                 }
 689                 return $arr;
 690         }
 691
 692         /**
 693          * Get an array of existing categories, with the name in the key and sort key in the value.
 694          * @private
 695          */
 696         function getExistingCategories() {
 697                 $res = $this->mDb->select( 'categorylinks', array( 'cl_to', 'cl_sortkey_prefix' ),
 698                         array( 'cl_from' => $this->mId ), __METHOD__, $this->mOptions );
 699                 $arr = array();
 700                 foreach ( $res as $row ) {
 701                         $arr[$row->cl_to] = $row->cl_sortkey_prefix;
 702                 }
 703                 return $arr;
 704         }
 705
 706         /**
 707          * Get an array of existing interlanguage links, with the language code in the key and the
 708          * title in the value.
 709          * @private
 710          */
 711         function getExistingInterlangs() {
 712                 $res = $this->mDb->select( 'langlinks', array( 'll_lang', 'll_title' ),
 713                         array( 'll_from' => $this->mId ), __METHOD__, $this->mOptions );
 714                 $arr = array();
 715                 foreach ( $res as $row ) {
 716                         $arr[$row->ll_lang] = $row->ll_title;
 717                 }
 718                 return $arr;
 719         }
 720
 721         /**
 722          * Get an array of existing inline interwiki links, as a 2-D array
 723          * @return array (prefix => array(dbkey => 1))
 724          */
 725         protected function getExistingInterwikis() {
 726                 $res = $this->mDb->select( 'iwlinks', array( 'iwl_prefix', 'iwl_title' ),
 727                         array( 'iwl_from' => $this->mId ), __METHOD__, $this->mOptions );
 728                 $arr = array();
 729                 foreach ( $res as $row ) {
 730                         if ( !isset( $arr[$row->iwl_prefix] ) ) {
 731                                 $arr[$row->iwl_prefix] = array();
 732                         }
 733                         $arr[$row->iwl_prefix][$row->iwl_title] = 1;
 734                 }
 735                 return $arr;
 736         }
 737
 738         /**
 739          * Get an array of existing categories, with the name in the key and sort key in the value.
 740          * @private
 741          */
 742         function getExistingProperties() {
 743                 $res = $this->mDb->select( 'page_props', array( 'pp_propname', 'pp_value' ),
 744                         array( 'pp_page' => $this->mId ), __METHOD__, $this->mOptions );
 745                 $arr = array();
 746                 foreach ( $res as $row ) {
 747                         $arr[$row->pp_propname] = $row->pp_value;
 748                 }
 749                 return $arr;
 750         }
 751
 752
 753         /**
 754          * Return the title object of the page being updated
 755          */
 756         function getTitle() {
 757                 return $this->mTitle;
 758         }
 759
 760         /**
 761          * Return the list of images used as generated by the parser
 762          */
 763         public function getImages() {
 764                 return $this->mImages;
 765         }
 766
 767         /**
 768          * Invalidate any necessary link lists related to page property changes
 769          */
 770         function invalidateProperties( $changed ) {
 771                 global $wgPagePropLinkInvalidations;
 772
 773                 foreach ( $changed as $name => $value ) {
 774                         if ( isset( $wgPagePropLinkInvalidations[$name] ) ) {
 775                                 $inv = $wgPagePropLinkInvalidations[$name];
 776                                 if ( !is_array( $inv ) ) {
 777                                         $inv = array( $inv );
 778                                 }
 779                                 foreach ( $inv as $table ) {
 780                                         $update = new HTMLCacheUpdate( $this->mTitle, $table );
 781                                         $update->doUpdate();
 782                                 }
 783                         }
 784                 }
 785         }
 786 }