includes/LinksUpdate.php

   1 <?php
   2 /**
   3  * See docs/deferred.txt
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @todo document (e.g. one-sentence top-level class description).
  21  */
  22 class LinksUpdate extends SecondaryDBDataUpdate {
  23
  24         /**@{{
  25          * @private
  26          */
  27         var $mId,            //!< Page ID of the article linked from
  28         $mTitle,         //!< Title object of the article linked from
  29         $mParserOutput,  //!< Whether to queue jobs for recursive update
  30         $mLinks,         //!< Map of title strings to IDs for the links in the document
  31                 $mImages,        //!< DB keys of the images used, in the array key only
  32                 $mTemplates,     //!< Map of title strings to IDs for the template references, including broken ones
  33                 $mExternals,     //!< URLs of external links, array key only
  34                 $mCategories,    //!< Map of category names to sort keys
  35                 $mInterlangs,    //!< Map of language codes to titles
  36                 $mProperties,    //!< Map of arbitrary name to value
  37                 $mRecursive;     //!< Whether to queue jobs for recursive updates
  38         /**@}}*/
  39
  40         /**
  41          * Constructor
  42          *
  43          * @param $title Title of the page we're updating
  44          * @param $parserOutput ParserOutput: output from a full parse of this page
  45          * @param $recursive Boolean: queue jobs for recursive updates?
  46          */
  47         function __construct( $title, $parserOutput, $recursive = true ) {
  48         parent::__construct( );
  49
  50         if ( !is_object( $title ) ) {
  51             throw new MWException( "The calling convention to LinksUpdate::LinksUpdate() has changed. " .
  52                 "Please see Article::editUpdates() for an invocation example.\n" );
  53         }
  54
  55         if ( !is_object( $title ) ) {
  56                         throw new MWException( "The calling convention to LinksUpdate::__construct() has changed. " .
  57                                 "Please see WikiPage::doEditUpdates() for an invocation example.\n" );
  58                 }
  59         $this->mTitle = $title;
  60         $this->mId = $title->getArticleID();
  61
  62         $this->mParserOutput = $parserOutput;
  63
  64                 $this->mLinks = $parserOutput->getLinks();
  65                 $this->mImages = $parserOutput->getImages();
  66                 $this->mTemplates = $parserOutput->getTemplates();
  67                 $this->mExternals = $parserOutput->getExternalLinks();
  68                 $this->mCategories = $parserOutput->getCategories();
  69                 $this->mProperties = $parserOutput->getProperties();
  70                 $this->mInterwikis = $parserOutput->getInterwikiLinks();
  71
  72                 # Convert the format of the interlanguage links
  73                 # I didn't want to change it in the ParserOutput, because that array is passed all
  74                 # the way back to the skin, so either a skin API break would be required, or an
  75                 # inefficient back-conversion.
  76                 $ill = $parserOutput->getLanguageLinks();
  77                 $this->mInterlangs = array();
  78                 foreach ( $ill as $link ) {
  79                         list( $key, $title ) = explode( ':', $link, 2 );
  80                         $this->mInterlangs[$key] = $title;
  81                 }
  82
  83                 foreach ( $this->mCategories as &$sortkey ) {
  84                         # If the sortkey is longer then 255 bytes,
  85                         # it truncated by DB, and then doesn't get
  86                         # matched when comparing existing vs current
  87                         # categories, causing bug 25254.
  88                         # Also. substr behaves weird when given "".
  89                         if ( $sortkey !== '' ) {
  90                                 $sortkey = substr( $sortkey, 0, 255 );
  91                         }
  92                 }
  93
  94                 $this->mRecursive = $recursive;
  95
  96                 wfRunHooks( 'LinksUpdateConstructed', array( &$this ) );
  97         }
  98
  99         /**
 100          * Update link tables with outgoing links from an updated article
 101          */
 102         public function doUpdate() {
 103                 global $wgUseDumbLinkUpdate;
 104
 105                 wfRunHooks( 'LinksUpdate', array( &$this ) );
 106                 if ( $wgUseDumbLinkUpdate ) {
 107                         $this->doDumbUpdate();
 108                 } else {
 109                         $this->doIncrementalUpdate();
 110                 }
 111                 wfRunHooks( 'LinksUpdateComplete', array( &$this ) );
 112         }
 113
 114         protected function doIncrementalUpdate() {
 115                 wfProfileIn( __METHOD__ );
 116
 117                 # Page links
 118                 $existing = $this->getExistingLinks();
 119                 $this->incrTableUpdate( 'pagelinks', 'pl', $this->getLinkDeletions( $existing ),
 120                         $this->getLinkInsertions( $existing ) );
 121
 122                 # Image links
 123                 $existing = $this->getExistingImages();
 124
 125                 $imageDeletes = $this->getImageDeletions( $existing );
 126                 $this->incrTableUpdate( 'imagelinks', 'il', $imageDeletes,
 127                         $this->getImageInsertions( $existing ) );
 128
 129                 # Invalidate all image description pages which had links added or removed
 130                 $imageUpdates = $imageDeletes + array_diff_key( $this->mImages, $existing );
 131                 $this->invalidateImageDescriptions( $imageUpdates );
 132
 133                 # External links
 134                 $existing = $this->getExistingExternals();
 135                 $this->incrTableUpdate( 'externallinks', 'el', $this->getExternalDeletions( $existing ),
 136                         $this->getExternalInsertions( $existing ) );
 137
 138                 # Language links
 139                 $existing = $this->getExistingInterlangs();
 140                 $this->incrTableUpdate( 'langlinks', 'll', $this->getInterlangDeletions( $existing ),
 141                         $this->getInterlangInsertions( $existing ) );
 142
 143                 # Inline interwiki links
 144                 $existing = $this->getExistingInterwikis();
 145                 $this->incrTableUpdate( 'iwlinks', 'iwl', $this->getInterwikiDeletions( $existing ),
 146                         $this->getInterwikiInsertions( $existing ) );
 147
 148                 # Template links
 149                 $existing = $this->getExistingTemplates();
 150                 $this->incrTableUpdate( 'templatelinks', 'tl', $this->getTemplateDeletions( $existing ),
 151                         $this->getTemplateInsertions( $existing ) );
 152
 153                 # Category links
 154                 $existing = $this->getExistingCategories();
 155
 156                 $categoryDeletes = $this->getCategoryDeletions( $existing );
 157
 158                 $this->incrTableUpdate( 'categorylinks', 'cl', $categoryDeletes,
 159                         $this->getCategoryInsertions( $existing ) );
 160
 161                 # Invalidate all categories which were added, deleted or changed (set symmetric difference)
 162                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 163                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 164                 $this->invalidateCategories( $categoryUpdates );
 165                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 166
 167                 # Page properties
 168                 $existing = $this->getExistingProperties();
 169
 170                 $propertiesDeletes = $this->getPropertyDeletions( $existing );
 171
 172                 $this->incrTableUpdate( 'page_props', 'pp', $propertiesDeletes,
 173                         $this->getPropertyInsertions( $existing ) );
 174
 175                 # Invalidate the necessary pages
 176                 $changed = $propertiesDeletes + array_diff_assoc( $this->mProperties, $existing );
 177                 $this->invalidateProperties( $changed );
 178
 179                 # Refresh links of all pages including this page
 180                 # This will be in a separate transaction
 181                 if ( $this->mRecursive ) {
 182                         $this->queueRecursiveJobs();
 183                 }
 184
 185                 wfProfileOut( __METHOD__ );
 186         }
 187
 188         /**
 189          * Link update which clears the previous entries and inserts new ones
 190          * May be slower or faster depending on level of lock contention and write speed of DB
 191          * Also useful where link table corruption needs to be repaired, e.g. in refreshLinks.php
 192          */
 193         protected function doDumbUpdate() {
 194                 wfProfileIn( __METHOD__ );
 195
 196                 # Refresh category pages and image description pages
 197                 $existing = $this->getExistingCategories();
 198                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 199                 $categoryDeletes = array_diff_assoc( $existing, $this->mCategories );
 200                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 201                 $existing = $this->getExistingImages();
 202                 $imageUpdates = array_diff_key( $existing, $this->mImages ) + array_diff_key( $this->mImages, $existing );
 203
 204                 $this->dumbTableUpdate( 'pagelinks',     $this->getLinkInsertions(),     'pl_from' );
 205                 $this->dumbTableUpdate( 'imagelinks',    $this->getImageInsertions(),    'il_from' );
 206                 $this->dumbTableUpdate( 'categorylinks', $this->getCategoryInsertions(), 'cl_from' );
 207                 $this->dumbTableUpdate( 'templatelinks', $this->getTemplateInsertions(), 'tl_from' );
 208                 $this->dumbTableUpdate( 'externallinks', $this->getExternalInsertions(), 'el_from' );
 209                 $this->dumbTableUpdate( 'langlinks',     $this->getInterlangInsertions(),'ll_from' );
 210                 $this->dumbTableUpdate( 'iwlinks',       $this->getInterwikiInsertions(),'iwl_from' );
 211                 $this->dumbTableUpdate( 'page_props',    $this->getPropertyInsertions(), 'pp_page' );
 212
 213                 # Update the cache of all the category pages and image description
 214                 # pages which were changed, and fix the category table count
 215                 $this->invalidateCategories( $categoryUpdates );
 216                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 217                 $this->invalidateImageDescriptions( $imageUpdates );
 218
 219                 # Refresh links of all pages including this page
 220                 # This will be in a separate transaction
 221                 if ( $this->mRecursive ) {
 222                         $this->queueRecursiveJobs();
 223                 }
 224
 225                 wfProfileOut( __METHOD__ );
 226         }
 227
 228         function queueRecursiveJobs() {
 229                 global $wgUpdateRowsPerJob;
 230                 wfProfileIn( __METHOD__ );
 231
 232                 $cache = $this->mTitle->getBacklinkCache();
 233                 $batches = $cache->partition( 'templatelinks', $wgUpdateRowsPerJob );
 234                 if ( !$batches ) {
 235                         wfProfileOut( __METHOD__ );
 236                         return;
 237                 }
 238                 $jobs = array();
 239                 foreach ( $batches as $batch ) {
 240                         list( $start, $end ) = $batch;
 241                         $params = array(
 242                                 'table' => 'templatelinks',
 243                                 'start' => $start,
 244                                 'end' => $end,
 245                         );
 246                         $jobs[] = new RefreshLinksJob2( $this->mTitle, $params );
 247                 }
 248                 Job::batchInsert( $jobs );
 249
 250                 wfProfileOut( __METHOD__ );
 251         }
 252
 253         /**
 254          * @param $cats
 255          */
 256         function invalidateCategories( $cats ) {
 257                 $this->invalidatePages( NS_CATEGORY, array_keys( $cats ) );
 258         }
 259
 260         /**
 261          * Update all the appropriate counts in the category table.
 262          * @param $added array associative array of category name => sort key
 263          * @param $deleted array associative array of category name => sort key
 264          */
 265         function updateCategoryCounts( $added, $deleted ) {
 266                 $a = WikiPage::factory( $this->mTitle );
 267                 $a->updateCategoryCounts(
 268                         array_keys( $added ), array_keys( $deleted )
 269                 );
 270         }
 271
 272         /**
 273          * @param $images
 274          */
 275         function invalidateImageDescriptions( $images ) {
 276                 $this->invalidatePages( NS_FILE, array_keys( $images ) );
 277         }
 278
 279     /**
 280      * @param $table
 281      * @param $insertions
 282      * @param $fromField
 283      */
 284     private function dumbTableUpdate( $table, $insertions, $fromField ) {
 285         $this->mDb->delete( $table, array( $fromField => $this->mId ), __METHOD__ );
 286         if ( count( $insertions ) ) {
 287             # The link array was constructed without FOR UPDATE, so there may
 288             # be collisions.  This may cause minor link table inconsistencies,
 289             # which is better than crippling the site with lock contention.
 290             $this->mDb->insert( $table, $insertions, __METHOD__, array( 'IGNORE' ) );
 291         }
 292     }
 293
 294         /**
 295          * Update a table by doing a delete query then an insert query
 296          * @param $table
 297          * @param $prefix
 298          * @param $deletions
 299          * @param $insertions
 300          */
 301         function incrTableUpdate( $table, $prefix, $deletions, $insertions ) {
 302                 if ( $table == 'page_props' ) {
 303                         $fromField = 'pp_page';
 304                 } else {
 305                         $fromField = "{$prefix}_from";
 306                 }
 307                 $where = array( $fromField => $this->mId );
 308                 if ( $table == 'pagelinks' || $table == 'templatelinks' || $table == 'iwlinks' ) {
 309                         if ( $table == 'iwlinks' ) {
 310                                 $baseKey = 'iwl_prefix';
 311                         } else {
 312                                 $baseKey = "{$prefix}_namespace";
 313                         }
 314                         $clause = $this->mDb->makeWhereFrom2d( $deletions, $baseKey, "{$prefix}_title" );
 315                         if ( $clause ) {
 316                                 $where[] = $clause;
 317                         } else {
 318                                 $where = false;
 319                         }
 320                 } else {
 321                         if ( $table == 'langlinks' ) {
 322                                 $toField = 'll_lang';
 323                         } elseif ( $table == 'page_props' ) {
 324                                 $toField = 'pp_propname';
 325                         } else {
 326                                 $toField = $prefix . '_to';
 327                         }
 328                         if ( count( $deletions ) ) {
 329                                 $where[] = "$toField IN (" . $this->mDb->makeList( array_keys( $deletions ) ) . ')';
 330                         } else {
 331                                 $where = false;
 332                         }
 333                 }
 334                 if ( $where ) {
 335                         $this->mDb->delete( $table, $where, __METHOD__ );
 336                 }
 337                 if ( count( $insertions ) ) {
 338                         $this->mDb->insert( $table, $insertions, __METHOD__, 'IGNORE' );
 339                 }
 340         }
 341
 342         /**
 343          * Get an array of pagelinks insertions for passing to the DB
 344          * Skips the titles specified by the 2-D array $existing
 345          * @param $existing array
 346          * @return array
 347          */
 348         private function getLinkInsertions( $existing = array() ) {
 349                 $arr = array();
 350                 foreach( $this->mLinks as $ns => $dbkeys ) {
 351                         $diffs = isset( $existing[$ns] )
 352                                 ? array_diff_key( $dbkeys, $existing[$ns] )
 353                                 : $dbkeys;
 354                         foreach ( $diffs as $dbk => $id ) {
 355                                 $arr[] = array(
 356                                         'pl_from'      => $this->mId,
 357                                         'pl_namespace' => $ns,
 358                                         'pl_title'     => $dbk
 359                                 );
 360                         }
 361                 }
 362                 return $arr;
 363         }
 364
 365         /**
 366          * Get an array of template insertions. Like getLinkInsertions()
 367          * @param $existing array
 368          * @return array
 369          */
 370         private function getTemplateInsertions( $existing = array() ) {
 371                 $arr = array();
 372                 foreach( $this->mTemplates as $ns => $dbkeys ) {
 373                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 374                         foreach ( $diffs as $dbk => $id ) {
 375                                 $arr[] = array(
 376                                         'tl_from'      => $this->mId,
 377                                         'tl_namespace' => $ns,
 378                                         'tl_title'     => $dbk
 379                                 );
 380                         }
 381                 }
 382                 return $arr;
 383         }
 384
 385         /**
 386          * Get an array of image insertions
 387          * Skips the names specified in $existing
 388          * @param $existing array
 389          * @return array
 390          */
 391         private function getImageInsertions( $existing = array() ) {
 392                 $arr = array();
 393                 $diffs = array_diff_key( $this->mImages, $existing );
 394                 foreach( $diffs as $iname => $dummy ) {
 395                         $arr[] = array(
 396                                 'il_from' => $this->mId,
 397                                 'il_to'   => $iname
 398                         );
 399                 }
 400                 return $arr;
 401         }
 402
 403         /**
 404          * Get an array of externallinks insertions. Skips the names specified in $existing
 405          * @param $existing array
 406          * @return array
 407          */
 408         private function getExternalInsertions( $existing = array() ) {
 409                 $arr = array();
 410                 $diffs = array_diff_key( $this->mExternals, $existing );
 411                 foreach( $diffs as $url => $dummy ) {
 412                         foreach( wfMakeUrlIndexes( $url ) as $index ) {
 413                                 $arr[] = array(
 414                                         'el_from'   => $this->mId,
 415                                         'el_to'     => $url,
 416                                         'el_index'  => $index,
 417                                 );
 418                         }
 419                 }
 420                 return $arr;
 421         }
 422
 423         /**
 424          * Get an array of category insertions
 425          *
 426          * @param $existing array mapping existing category names to sort keys. If both
 427          * match a link in $this, the link will be omitted from the output
 428          *
 429          * @return array
 430          */
 431         private function getCategoryInsertions( $existing = array() ) {
 432                 global $wgContLang, $wgCategoryCollation;
 433                 $diffs = array_diff_assoc( $this->mCategories, $existing );
 434                 $arr = array();
 435                 foreach ( $diffs as $name => $prefix ) {
 436                         $nt = Title::makeTitleSafe( NS_CATEGORY, $name );
 437                         $wgContLang->findVariantLink( $name, $nt, true );
 438
 439                         if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
 440                                 $type = 'subcat';
 441                         } elseif ( $this->mTitle->getNamespace() == NS_FILE ) {
 442                                 $type = 'file';
 443                         } else {
 444                                 $type = 'page';
 445                         }
 446
 447                         # Treat custom sortkeys as a prefix, so that if multiple
 448                         # things are forced to sort as '*' or something, they'll
 449                         # sort properly in the category rather than in page_id
 450                         # order or such.
 451                         $sortkey = Collation::singleton()->getSortKey(
 452                                 $this->mTitle->getCategorySortkey( $prefix ) );
 453
 454                         $arr[] = array(
 455                                 'cl_from'    => $this->mId,
 456                                 'cl_to'      => $name,
 457                                 'cl_sortkey' => $sortkey,
 458                                 'cl_timestamp' => $this->mDb->timestamp(),
 459                                 'cl_sortkey_prefix' => $prefix,
 460                                 'cl_collation' => $wgCategoryCollation,
 461                                 'cl_type' => $type,
 462                         );
 463                 }
 464                 return $arr;
 465         }
 466
 467         /**
 468          * Get an array of interlanguage link insertions
 469          *
 470          * @param $existing Array mapping existing language codes to titles
 471          *
 472          * @return array
 473          */
 474         private function getInterlangInsertions( $existing = array() ) {
 475                 $diffs = array_diff_assoc( $this->mInterlangs, $existing );
 476                 $arr = array();
 477                 foreach( $diffs as $lang => $title ) {
 478                         $arr[] = array(
 479                                 'll_from'  => $this->mId,
 480                                 'll_lang'  => $lang,
 481                                 'll_title' => $title
 482                         );
 483                 }
 484                 return $arr;
 485         }
 486
 487         /**
 488          * Get an array of page property insertions
 489          * @param $existing array
 490          * @return array
 491          */
 492         function getPropertyInsertions( $existing = array() ) {
 493                 $diffs = array_diff_assoc( $this->mProperties, $existing );
 494                 $arr = array();
 495                 foreach ( $diffs as $name => $value ) {
 496                         $arr[] = array(
 497                                 'pp_page'      => $this->mId,
 498                                 'pp_propname'  => $name,
 499                                 'pp_value'     => $value,
 500                         );
 501                 }
 502                 return $arr;
 503         }
 504
 505         /**
 506          * Get an array of interwiki insertions for passing to the DB
 507          * Skips the titles specified by the 2-D array $existing
 508          * @param $existing array
 509          * @return array
 510          */
 511         private function getInterwikiInsertions( $existing = array() ) {
 512                 $arr = array();
 513                 foreach( $this->mInterwikis as $prefix => $dbkeys ) {
 514                         $diffs = isset( $existing[$prefix] ) ? array_diff_key( $dbkeys, $existing[$prefix] ) : $dbkeys;
 515                         foreach ( $diffs as $dbk => $id ) {
 516                                 $arr[] = array(
 517                                         'iwl_from'   => $this->mId,
 518                                         'iwl_prefix' => $prefix,
 519                                         'iwl_title'  => $dbk
 520                                 );
 521                         }
 522                 }
 523                 return $arr;
 524         }
 525
 526         /**
 527          * Given an array of existing links, returns those links which are not in $this
 528          * and thus should be deleted.
 529          * @param $existing array
 530          * @return array
 531          */
 532         private function getLinkDeletions( $existing ) {
 533                 $del = array();
 534                 foreach ( $existing as $ns => $dbkeys ) {
 535                         if ( isset( $this->mLinks[$ns] ) ) {
 536                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mLinks[$ns] );
 537                         } else {
 538                                 $del[$ns] = $existing[$ns];
 539                         }
 540                 }
 541                 return $del;
 542         }
 543
 544         /**
 545          * Given an array of existing templates, returns those templates which are not in $this
 546          * and thus should be deleted.
 547          * @param $existing array
 548          * @return array
 549          */
 550         private function getTemplateDeletions( $existing ) {
 551                 $del = array();
 552                 foreach ( $existing as $ns => $dbkeys ) {
 553                         if ( isset( $this->mTemplates[$ns] ) ) {
 554                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mTemplates[$ns] );
 555                         } else {
 556                                 $del[$ns] = $existing[$ns];
 557                         }
 558                 }
 559                 return $del;
 560         }
 561
 562         /**
 563          * Given an array of existing images, returns those images which are not in $this
 564          * and thus should be deleted.
 565          * @param $existing array
 566          * @return array
 567          */
 568         private function getImageDeletions( $existing ) {
 569                 return array_diff_key( $existing, $this->mImages );
 570         }
 571
 572         /**
 573          * Given an array of existing external links, returns those links which are not
 574          * in $this and thus should be deleted.
 575          * @param $existing array
 576          * @return array
 577          */
 578         private function getExternalDeletions( $existing ) {
 579                 return array_diff_key( $existing, $this->mExternals );
 580         }
 581
 582         /**
 583          * Given an array of existing categories, returns those categories which are not in $this
 584          * and thus should be deleted.
 585          * @param $existing array
 586          * @return array
 587          */
 588         private function getCategoryDeletions( $existing ) {
 589                 return array_diff_assoc( $existing, $this->mCategories );
 590         }
 591
 592         /**
 593          * Given an array of existing interlanguage links, returns those links which are not
 594          * in $this and thus should be deleted.
 595          * @param $existing array
 596          * @return array
 597          */
 598         private function getInterlangDeletions( $existing ) {
 599                 return array_diff_assoc( $existing, $this->mInterlangs );
 600         }
 601
 602         /**
 603          * Get array of properties which should be deleted.
 604          * @param $existing array
 605          * @return array
 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          * @param $existing array
 615          * @return array
 616          */
 617         private function getInterwikiDeletions( $existing ) {
 618                 $del = array();
 619                 foreach ( $existing as $prefix => $dbkeys ) {
 620                         if ( isset( $this->mInterwikis[$prefix] ) ) {
 621                                 $del[$prefix] = array_diff_key( $existing[$prefix], $this->mInterwikis[$prefix] );
 622                         } else {
 623                                 $del[$prefix] = $existing[$prefix];
 624                         }
 625                 }
 626                 return $del;
 627         }
 628
 629         /**
 630          * Get an array of existing links, as a 2-D array
 631          *
 632          * @return array
 633          */
 634         private 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          *
 650          * @return array
 651          */
 652         private function getExistingTemplates() {
 653                 $res = $this->mDb->select( 'templatelinks', array( 'tl_namespace', 'tl_title' ),
 654                         array( 'tl_from' => $this->mId ), __METHOD__, $this->mOptions );
 655                 $arr = array();
 656                 foreach ( $res as $row ) {
 657                         if ( !isset( $arr[$row->tl_namespace] ) ) {
 658                                 $arr[$row->tl_namespace] = array();
 659                         }
 660                         $arr[$row->tl_namespace][$row->tl_title] = 1;
 661                 }
 662                 return $arr;
 663         }
 664
 665         /**
 666          * Get an array of existing images, image names in the keys
 667          *
 668          * @return array
 669          */
 670         private function getExistingImages() {
 671                 $res = $this->mDb->select( 'imagelinks', array( 'il_to' ),
 672                         array( 'il_from' => $this->mId ), __METHOD__, $this->mOptions );
 673                 $arr = array();
 674                 foreach ( $res as $row ) {
 675                         $arr[$row->il_to] = 1;
 676                 }
 677                 return $arr;
 678         }
 679
 680         /**
 681          * Get an array of existing external links, URLs in the keys
 682          *
 683          * @return array
 684          */
 685         private function getExistingExternals() {
 686                 $res = $this->mDb->select( 'externallinks', array( 'el_to' ),
 687                         array( 'el_from' => $this->mId ), __METHOD__, $this->mOptions );
 688                 $arr = array();
 689                 foreach ( $res as $row ) {
 690                         $arr[$row->el_to] = 1;
 691                 }
 692                 return $arr;
 693         }
 694
 695         /**
 696          * Get an array of existing categories, with the name in the key and sort key in the value.
 697          *
 698          * @return array
 699          */
 700         private function getExistingCategories() {
 701                 $res = $this->mDb->select( 'categorylinks', array( 'cl_to', 'cl_sortkey_prefix' ),
 702                         array( 'cl_from' => $this->mId ), __METHOD__, $this->mOptions );
 703                 $arr = array();
 704                 foreach ( $res as $row ) {
 705                         $arr[$row->cl_to] = $row->cl_sortkey_prefix;
 706                 }
 707                 return $arr;
 708         }
 709
 710         /**
 711          * Get an array of existing interlanguage links, with the language code in the key and the
 712          * title in the value.
 713          *
 714          * @return array
 715          */
 716         private function getExistingInterlangs() {
 717                 $res = $this->mDb->select( 'langlinks', array( 'll_lang', 'll_title' ),
 718                         array( 'll_from' => $this->mId ), __METHOD__, $this->mOptions );
 719                 $arr = array();
 720                 foreach ( $res as $row ) {
 721                         $arr[$row->ll_lang] = $row->ll_title;
 722                 }
 723                 return $arr;
 724         }
 725
 726         /**
 727          * Get an array of existing inline interwiki links, as a 2-D array
 728          * @return array (prefix => array(dbkey => 1))
 729          */
 730         protected function getExistingInterwikis() {
 731                 $res = $this->mDb->select( 'iwlinks', array( 'iwl_prefix', 'iwl_title' ),
 732                         array( 'iwl_from' => $this->mId ), __METHOD__, $this->mOptions );
 733                 $arr = array();
 734                 foreach ( $res as $row ) {
 735                         if ( !isset( $arr[$row->iwl_prefix] ) ) {
 736                                 $arr[$row->iwl_prefix] = array();
 737                         }
 738                         $arr[$row->iwl_prefix][$row->iwl_title] = 1;
 739                 }
 740                 return $arr;
 741         }
 742
 743         /**
 744          * Get an array of existing categories, with the name in the key and sort key in the value.
 745          *
 746          * @return array
 747          */
 748         private function getExistingProperties() {
 749                 $res = $this->mDb->select( 'page_props', array( 'pp_propname', 'pp_value' ),
 750                         array( 'pp_page' => $this->mId ), __METHOD__, $this->mOptions );
 751                 $arr = array();
 752                 foreach ( $res as $row ) {
 753                         $arr[$row->pp_propname] = $row->pp_value;
 754                 }
 755                 return $arr;
 756         }
 757
 758     /**
 759      * Return the title object of the page being updated
 760      * @return Title
 761      */
 762     public function getTitle() {
 763         return $this->mTitle;
 764     }
 765
 766     /**
 767      * Returns parser output
 768      * @since 1.19
 769      * @return ParserOutput
 770      */
 771     public function getParserOutput() {
 772         return $this->mParserOutput;
 773     }
 774
 775         /**
 776          * Return the list of images used as generated by the parser
 777          * @return array
 778          */
 779         public function getImages() {
 780                 return $this->mImages;
 781         }
 782
 783         /**
 784          * Invalidate any necessary link lists related to page property changes
 785          * @param $changed
 786          */
 787         private function invalidateProperties( $changed ) {
 788                 global $wgPagePropLinkInvalidations;
 789
 790                 foreach ( $changed as $name => $value ) {
 791                         if ( isset( $wgPagePropLinkInvalidations[$name] ) ) {
 792                                 $inv = $wgPagePropLinkInvalidations[$name];
 793                                 if ( !is_array( $inv ) ) {
 794                                         $inv = array( $inv );
 795                                 }
 796                                 foreach ( $inv as $table ) {
 797                                         $update = new HTMLCacheUpdate( $this->mTitle, $table );
 798                                         $update->doUpdate();
 799                                 }
 800                         }
 801                 }
 802         }
 803 }