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,
 114                         $this->getImageInsertions( $existing ) );
 115
 116                 # Invalidate all image description pages which had links added or removed
 117                 $imageUpdates = $imageDeletes + array_diff_key( $this->mImages, $existing );
 118                 $this->invalidateImageDescriptions( $imageUpdates );
 119
 120                 # External links
 121                 $existing = $this->getExistingExternals();
 122                 $this->incrTableUpdate( 'externallinks', 'el', $this->getExternalDeletions( $existing ),
 123                 $this->getExternalInsertions( $existing ) );
 124
 125                 # Language links
 126                 $existing = $this->getExistingInterlangs();
 127                 $this->incrTableUpdate( 'langlinks', 'll', $this->getInterlangDeletions( $existing ),
 128                         $this->getInterlangInsertions( $existing ) );
 129
 130                 # Inline interwiki links
 131                 $existing = $this->getExistingInterwikis();
 132                 $this->incrTableUpdate( 'iwlinks', 'iwl', $this->getInterwikiDeletions( $existing ),
 133                         $this->getInterwikiInsertions( $existing ) );
 134
 135                 # Template links
 136                 $existing = $this->getExistingTemplates();
 137                 $this->incrTableUpdate( 'templatelinks', 'tl', $this->getTemplateDeletions( $existing ),
 138                         $this->getTemplateInsertions( $existing ) );
 139
 140                 # Category links
 141                 $existing = $this->getExistingCategories();
 142
 143                 $categoryDeletes = $this->getCategoryDeletions( $existing );
 144
 145                 $this->incrTableUpdate( 'categorylinks', 'cl', $categoryDeletes,
 146                         $this->getCategoryInsertions( $existing ) );
 147
 148                 # Invalidate all categories which were added, deleted or changed (set symmetric difference)
 149                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 150                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 151                 $this->invalidateCategories( $categoryUpdates );
 152                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 153
 154                 # Page properties
 155                 $existing = $this->getExistingProperties();
 156
 157                 $propertiesDeletes = $this->getPropertyDeletions( $existing );
 158
 159                 $this->incrTableUpdate( 'page_props', 'pp', $propertiesDeletes,
 160                         $this->getPropertyInsertions( $existing ) );
 161
 162                 # Invalidate the necessary pages
 163                 $changed = $propertiesDeletes + array_diff_assoc( $this->mProperties, $existing );
 164                 $this->invalidateProperties( $changed );
 165
 166                 # Refresh links of all pages including this page
 167                 # This will be in a separate transaction
 168                 if ( $this->mRecursive ) {
 169                         $this->queueRecursiveJobs();
 170                 }
 171
 172                 wfProfileOut( __METHOD__ );
 173         }
 174
 175         /**
 176          * Link update which clears the previous entries and inserts new ones
 177          * May be slower or faster depending on level of lock contention and write speed of DB
 178          * Also useful where link table corruption needs to be repaired, e.g. in refreshLinks.php
 179          */
 180         protected function doDumbUpdate() {
 181                 wfProfileIn( __METHOD__ );
 182
 183                 # Refresh category pages and image description pages
 184                 $existing = $this->getExistingCategories();
 185                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 186                 $categoryDeletes = array_diff_assoc( $existing, $this->mCategories );
 187                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 188                 $existing = $this->getExistingImages();
 189                 $imageUpdates = array_diff_key( $existing, $this->mImages ) + array_diff_key( $this->mImages, $existing );
 190
 191                 $this->dumbTableUpdate( 'pagelinks',     $this->getLinkInsertions(),     'pl_from' );
 192                 $this->dumbTableUpdate( 'imagelinks',    $this->getImageInsertions(),    'il_from' );
 193                 $this->dumbTableUpdate( 'categorylinks', $this->getCategoryInsertions(), 'cl_from' );
 194                 $this->dumbTableUpdate( 'templatelinks', $this->getTemplateInsertions(), 'tl_from' );
 195                 $this->dumbTableUpdate( 'externallinks', $this->getExternalInsertions(), 'el_from' );
 196                 $this->dumbTableUpdate( 'langlinks',     $this->getInterlangInsertions(),'ll_from' );
 197                 $this->dumbTableUpdate( 'iwlinks',       $this->getInterwikiInsertions(),'iwl_from' );
 198                 $this->dumbTableUpdate( 'page_props',    $this->getPropertyInsertions(), 'pp_page' );
 199
 200                 # Update the cache of all the category pages and image description
 201                 # pages which were changed, and fix the category table count
 202                 $this->invalidateCategories( $categoryUpdates );
 203                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 204                 $this->invalidateImageDescriptions( $imageUpdates );
 205
 206                 # Refresh links of all pages including this page
 207                 # This will be in a separate transaction
 208                 if ( $this->mRecursive ) {
 209                         $this->queueRecursiveJobs();
 210                 }
 211
 212                 wfProfileOut( __METHOD__ );
 213         }
 214
 215         function queueRecursiveJobs() {
 216                 global $wgUpdateRowsPerJob;
 217                 wfProfileIn( __METHOD__ );
 218
 219                 $cache = $this->mTitle->getBacklinkCache();
 220                 $batches = $cache->partition( 'templatelinks', $wgUpdateRowsPerJob );
 221                 if ( !$batches ) {
 222                         wfProfileOut( __METHOD__ );
 223                         return;
 224                 }
 225                 $jobs = array();
 226                 foreach ( $batches as $batch ) {
 227                         list( $start, $end ) = $batch;
 228                         $params = array(
 229                                 'start' => $start,
 230                                 'end' => $end,
 231                         );
 232                         $jobs[] = new RefreshLinksJob2( $this->mTitle, $params );
 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 $namespace Integer
 243          * @param $dbkeys Array
 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                 foreach ( $res as $row ) {
 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_FILE, 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          * Update a table by doing a delete query then an insert query
 316          * @private
 317          */
 318         function incrTableUpdate( $table, $prefix, $deletions, $insertions ) {
 319                 if ( $table == 'page_props' ) {
 320                         $fromField = 'pp_page';
 321                 } else {
 322                         $fromField = "{$prefix}_from";
 323                 }
 324                 $where = array( $fromField => $this->mId );
 325                 if ( $table == 'pagelinks' || $table == 'templatelinks' || $table == 'iwlinks' ) {
 326                         if ( $table == 'iwlinks' ) {
 327                                 $baseKey = 'iwl_prefix';
 328                         } else {
 329                                 $baseKey = "{$prefix}_namespace";
 330                         }
 331                         $clause = $this->mDb->makeWhereFrom2d( $deletions, $baseKey, "{$prefix}_title" );
 332                         if ( $clause ) {
 333                                 $where[] = $clause;
 334                         } else {
 335                                 $where = false;
 336                         }
 337                 } else {
 338                         if ( $table == 'langlinks' ) {
 339                                 $toField = 'll_lang';
 340                         } elseif ( $table == 'page_props' ) {
 341                                 $toField = 'pp_propname';
 342                         } else {
 343                                 $toField = $prefix . '_to';
 344                         }
 345                         if ( count( $deletions ) ) {
 346                                 $where[] = "$toField IN (" . $this->mDb->makeList( array_keys( $deletions ) ) . ')';
 347                         } else {
 348                                 $where = false;
 349                         }
 350                 }
 351                 if ( $where ) {
 352                         $this->mDb->delete( $table, $where, __METHOD__ );
 353                 }
 354                 if ( count( $insertions ) ) {
 355                         $this->mDb->insert( $table, $insertions, __METHOD__, 'IGNORE' );
 356                 }
 357         }
 358
 359
 360         /**
 361          * Get an array of pagelinks insertions for passing to the DB
 362          * Skips the titles specified by the 2-D array $existing
 363          * @private
 364          */
 365         function getLinkInsertions( $existing = array() ) {
 366                 $arr = array();
 367                 foreach( $this->mLinks as $ns => $dbkeys ) {
 368                         $diffs = isset( $existing[$ns] )
 369                                 ? array_diff_key( $dbkeys, $existing[$ns] )
 370                                 : $dbkeys;
 371                         foreach ( $diffs as $dbk => $id ) {
 372                                 $arr[] = array(
 373                                         'pl_from'      => $this->mId,
 374                                         'pl_namespace' => $ns,
 375                                         'pl_title'     => $dbk
 376                                 );
 377                         }
 378                 }
 379                 return $arr;
 380         }
 381
 382         /**
 383          * Get an array of template insertions. Like getLinkInsertions()
 384          * @private
 385          */
 386         function getTemplateInsertions( $existing = array() ) {
 387                 $arr = array();
 388                 foreach( $this->mTemplates as $ns => $dbkeys ) {
 389                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 390                         foreach ( $diffs as $dbk => $id ) {
 391                                 $arr[] = array(
 392                                         'tl_from'      => $this->mId,
 393                                         'tl_namespace' => $ns,
 394                                         'tl_title'     => $dbk
 395                                 );
 396                         }
 397                 }
 398                 return $arr;
 399         }
 400
 401         /**
 402          * Get an array of image insertions
 403          * Skips the names specified in $existing
 404          * @private
 405          */
 406         function getImageInsertions( $existing = array() ) {
 407                 $arr = array();
 408                 $diffs = array_diff_key( $this->mImages, $existing );
 409                 foreach( $diffs as $iname => $dummy ) {
 410                         $arr[] = array(
 411                                 'il_from' => $this->mId,
 412                                 'il_to'   => $iname
 413                         );
 414                 }
 415                 return $arr;
 416         }
 417
 418         /**
 419          * Get an array of externallinks insertions. Skips the names specified in $existing
 420          * @private
 421          */
 422         function getExternalInsertions( $existing = array() ) {
 423                 $arr = array();
 424                 $diffs = array_diff_key( $this->mExternals, $existing );
 425                 foreach( $diffs as $url => $dummy ) {
 426                         $arr[] = array(
 427                                 'el_from'   => $this->mId,
 428                                 'el_to'     => $url,
 429                                 'el_index'  => wfMakeUrlIndex( $url ),
 430                         );
 431                 }
 432                 return $arr;
 433         }
 434
 435         /**
 436          * Get an array of category insertions
 437          *
 438          * @param $existing Array mapping existing category names to sort keys. If both
 439          * match a link in $this, the link will be omitted from the output
 440          * @private
 441          */
 442         function getCategoryInsertions( $existing = array() ) {
 443                 global $wgContLang, $wgCategoryCollation;
 444                 $diffs = array_diff_assoc( $this->mCategories, $existing );
 445                 $arr = array();
 446                 foreach ( $diffs as $name => $prefix ) {
 447                         $nt = Title::makeTitleSafe( NS_CATEGORY, $name );
 448                         $wgContLang->findVariantLink( $name, $nt, true );
 449
 450                         if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
 451                                 $type = 'subcat';
 452                         } elseif ( $this->mTitle->getNamespace() == NS_FILE ) {
 453                                 $type = 'file';
 454                         } else {
 455                                 $type = 'page';
 456                         }
 457
 458                         # Treat custom sortkeys as a prefix, so that if multiple
 459                         # things are forced to sort as '*' or something, they'll
 460                         # sort properly in the category rather than in page_id
 461                         # order or such.
 462                         $sortkey = Collation::singleton()->getSortKey(
 463                                 $this->mTitle->getCategorySortkey( $prefix ) );
 464
 465                         $arr[] = array(
 466                                 'cl_from'    => $this->mId,
 467                                 'cl_to'      => $name,
 468                                 'cl_sortkey' => $sortkey,
 469                                 'cl_timestamp' => $this->mDb->timestamp(),
 470                                 'cl_sortkey_prefix' => $prefix,
 471                                 'cl_collation' => $wgCategoryCollation,
 472                                 'cl_type' => $type,
 473                         );
 474                 }
 475                 return $arr;
 476         }
 477
 478         /**
 479          * Get an array of interlanguage link insertions
 480          *
 481          * @param $existing Array mapping existing language codes to titles
 482          * @private
 483          */
 484         function getInterlangInsertions( $existing = array() ) {
 485             $diffs = array_diff_assoc( $this->mInterlangs, $existing );
 486             $arr = array();
 487             foreach( $diffs as $lang => $title ) {
 488                 $arr[] = array(
 489                     'll_from'  => $this->mId,
 490                     'll_lang'  => $lang,
 491                     'll_title' => $title
 492                 );
 493             }
 494             return $arr;
 495         }
 496
 497         /**
 498          * Get an array of page property insertions
 499          */
 500         function getPropertyInsertions( $existing = array() ) {
 501                 $diffs = array_diff_assoc( $this->mProperties, $existing );
 502                 $arr = array();
 503                 foreach ( $diffs as $name => $value ) {
 504                         $arr[] = array(
 505                                 'pp_page'      => $this->mId,
 506                                 'pp_propname'  => $name,
 507                                 'pp_value'     => $value,
 508                         );
 509                 }
 510                 return $arr;
 511         }
 512
 513         /**
 514          * Get an array of interwiki insertions for passing to the DB
 515          * Skips the titles specified by the 2-D array $existing
 516          * @private
 517          */
 518         function getInterwikiInsertions( $existing = array() ) {
 519                 $arr = array();
 520                 foreach( $this->mInterwikis as $prefix => $dbkeys ) {
 521                         $diffs = isset( $existing[$prefix] ) ? array_diff_key( $dbkeys, $existing[$prefix] ) : $dbkeys;
 522                         foreach ( $diffs as $dbk => $id ) {
 523                                 $arr[] = array(
 524                                         'iwl_from'   => $this->mId,
 525                                         'iwl_prefix' => $prefix,
 526                                         'iwl_title'  => $dbk
 527                                 );
 528                         }
 529                 }
 530                 return $arr;
 531         }
 532
 533         /**
 534          * Given an array of existing links, returns those links which are not in $this
 535          * and thus should be deleted.
 536          * @private
 537          */
 538         function getLinkDeletions( $existing ) {
 539                 $del = array();
 540                 foreach ( $existing as $ns => $dbkeys ) {
 541                         if ( isset( $this->mLinks[$ns] ) ) {
 542                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mLinks[$ns] );
 543                         } else {
 544                                 $del[$ns] = $existing[$ns];
 545                         }
 546                 }
 547                 return $del;
 548         }
 549
 550         /**
 551          * Given an array of existing templates, returns those templates which are not in $this
 552          * and thus should be deleted.
 553          * @private
 554          */
 555         function getTemplateDeletions( $existing ) {
 556                 $del = array();
 557                 foreach ( $existing as $ns => $dbkeys ) {
 558                         if ( isset( $this->mTemplates[$ns] ) ) {
 559                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mTemplates[$ns] );
 560                         } else {
 561                                 $del[$ns] = $existing[$ns];
 562                         }
 563                 }
 564                 return $del;
 565         }
 566
 567         /**
 568          * Given an array of existing images, returns those images which are not in $this
 569          * and thus should be deleted.
 570          * @private
 571          */
 572         function getImageDeletions( $existing ) {
 573                 return array_diff_key( $existing, $this->mImages );
 574         }
 575
 576         /**
 577          * Given an array of existing external links, returns those links which are not
 578          * in $this and thus should be deleted.
 579          * @private
 580          */
 581         function getExternalDeletions( $existing ) {
 582                 return array_diff_key( $existing, $this->mExternals );
 583         }
 584
 585         /**
 586          * Given an array of existing categories, returns those categories which are not in $this
 587          * and thus should be deleted.
 588          * @private
 589          */
 590         function getCategoryDeletions( $existing ) {
 591                 return array_diff_assoc( $existing, $this->mCategories );
 592         }
 593
 594         /**
 595          * Given an array of existing interlanguage links, returns those links which are not
 596          * in $this and thus should be deleted.
 597          * @private
 598          */
 599         function getInterlangDeletions( $existing ) {
 600             return array_diff_assoc( $existing, $this->mInterlangs );
 601         }
 602
 603         /**
 604          * Get array of properties which should be deleted.
 605          * @private
 606          */
 607         function getPropertyDeletions( $existing ) {
 608                 return array_diff_assoc( $existing, $this->mProperties );
 609         }
 610
 611         /**
 612          * Given an array of existing interwiki links, returns those links which are not in $this
 613          * and thus should be deleted.
 614          * @private
 615          */
 616         function getInterwikiDeletions( $existing ) {
 617                 $del = array();
 618                 foreach ( $existing as $prefix => $dbkeys ) {
 619                         if ( isset( $this->mInterwikis[$prefix] ) ) {
 620                                 $del[$prefix] = array_diff_key( $existing[$prefix], $this->mInterwikis[$prefix] );
 621                         } else {
 622                                 $del[$prefix] = $existing[$prefix];
 623                         }
 624                 }
 625                 return $del;
 626         }
 627
 628         /**
 629          * Get an array of existing links, as a 2-D array
 630          * @private
 631          */
 632         function getExistingLinks() {
 633                 $res = $this->mDb->select( 'pagelinks', array( 'pl_namespace', 'pl_title' ),
 634                         array( 'pl_from' => $this->mId ), __METHOD__, $this->mOptions );
 635                 $arr = array();
 636                 foreach ( $res as $row ) {
 637                         if ( !isset( $arr[$row->pl_namespace] ) ) {
 638                                 $arr[$row->pl_namespace] = array();
 639                         }
 640                         $arr[$row->pl_namespace][$row->pl_title] = 1;
 641                 }
 642                 return $arr;
 643         }
 644
 645         /**
 646          * Get an array of existing templates, as a 2-D array
 647          * @private
 648          */
 649         function getExistingTemplates() {
 650                 $res = $this->mDb->select( 'templatelinks', array( 'tl_namespace', 'tl_title' ),
 651                         array( 'tl_from' => $this->mId ), __METHOD__, $this->mOptions );
 652                 $arr = array();
 653                 foreach ( $res as $row ) {
 654                         if ( !isset( $arr[$row->tl_namespace] ) ) {
 655                                 $arr[$row->tl_namespace] = array();
 656                         }
 657                         $arr[$row->tl_namespace][$row->tl_title] = 1;
 658                 }
 659                 return $arr;
 660         }
 661
 662         /**
 663          * Get an array of existing images, image names in the keys
 664          * @private
 665          */
 666         function getExistingImages() {
 667                 $res = $this->mDb->select( 'imagelinks', array( 'il_to' ),
 668                         array( 'il_from' => $this->mId ), __METHOD__, $this->mOptions );
 669                 $arr = array();
 670                 foreach ( $res as $row ) {
 671                         $arr[$row->il_to] = 1;
 672                 }
 673                 return $arr;
 674         }
 675
 676         /**
 677          * Get an array of existing external links, URLs in the keys
 678          * @private
 679          */
 680         function getExistingExternals() {
 681                 $res = $this->mDb->select( 'externallinks', array( 'el_to' ),
 682                         array( 'el_from' => $this->mId ), __METHOD__, $this->mOptions );
 683                 $arr = array();
 684                 foreach ( $res as $row ) {
 685                         $arr[$row->el_to] = 1;
 686                 }
 687                 return $arr;
 688         }
 689
 690         /**
 691          * Get an array of existing categories, with the name in the key and sort key in the value.
 692          * @private
 693          */
 694         function getExistingCategories() {
 695                 $res = $this->mDb->select( 'categorylinks', array( 'cl_to', 'cl_sortkey_prefix' ),
 696                         array( 'cl_from' => $this->mId ), __METHOD__, $this->mOptions );
 697                 $arr = array();
 698                 foreach ( $res as $row ) {
 699                         $arr[$row->cl_to] = $row->cl_sortkey_prefix;
 700                 }
 701                 return $arr;
 702         }
 703
 704         /**
 705          * Get an array of existing interlanguage links, with the language code in the key and the
 706          * title in the value.
 707          * @private
 708          */
 709         function getExistingInterlangs() {
 710                 $res = $this->mDb->select( 'langlinks', array( 'll_lang', 'll_title' ),
 711                         array( 'll_from' => $this->mId ), __METHOD__, $this->mOptions );
 712                 $arr = array();
 713                 foreach ( $res as $row ) {
 714                         $arr[$row->ll_lang] = $row->ll_title;
 715                 }
 716                 return $arr;
 717         }
 718
 719         /**
 720          * Get an array of existing inline interwiki links, as a 2-D array
 721          * @return array (prefix => array(dbkey => 1))
 722          */
 723         protected function getExistingInterwikis() {
 724                 $res = $this->mDb->select( 'iwlinks', array( 'iwl_prefix', 'iwl_title' ),
 725                         array( 'iwl_from' => $this->mId ), __METHOD__, $this->mOptions );
 726                 $arr = array();
 727                 foreach ( $res as $row ) {
 728                         if ( !isset( $arr[$row->iwl_prefix] ) ) {
 729                                 $arr[$row->iwl_prefix] = array();
 730                         }
 731                         $arr[$row->iwl_prefix][$row->iwl_title] = 1;
 732                 }
 733                 return $arr;
 734         }
 735
 736         /**
 737          * Get an array of existing categories, with the name in the key and sort key in the value.
 738          * @private
 739          */
 740         function getExistingProperties() {
 741                 $res = $this->mDb->select( 'page_props', array( 'pp_propname', 'pp_value' ),
 742                         array( 'pp_page' => $this->mId ), __METHOD__, $this->mOptions );
 743                 $arr = array();
 744                 foreach ( $res as $row ) {
 745                         $arr[$row->pp_propname] = $row->pp_value;
 746                 }
 747                 return $arr;
 748         }
 749
 750
 751         /**
 752          * Return the title object of the page being updated
 753          */
 754         function getTitle() {
 755                 return $this->mTitle;
 756         }
 757
 758         /**
 759          * Return the list of images used as generated by the parser
 760          */
 761         public function getImages() {
 762                 return $this->mImages;
 763         }
 764
 765         /**
 766          * Invalidate any necessary link lists related to page property changes
 767          */
 768         function invalidateProperties( $changed ) {
 769                 global $wgPagePropLinkInvalidations;
 770
 771                 foreach ( $changed as $name => $value ) {
 772                         if ( isset( $wgPagePropLinkInvalidations[$name] ) ) {
 773                                 $inv = $wgPagePropLinkInvalidations[$name];
 774                                 if ( !is_array( $inv ) ) {
 775                                         $inv = array( $inv );
 776                                 }
 777                                 foreach ( $inv as $table ) {
 778                                         $update = new HTMLCacheUpdate( $this->mTitle, $table );
 779                                         $update->doUpdate();
 780                                 }
 781                         }
 782                 }
 783         }
 784 }