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 {
  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                 $mLinks,         //!< Map of title strings to IDs for the links in the document
  30                 $mImages,        //!< DB keys of the images used, in the array key only
  31                 $mTemplates,     //!< Map of title strings to IDs for the template references, including broken ones
  32                 $mExternals,     //!< URLs of external links, array key only
  33                 $mCategories,    //!< Map of category names to sort keys
  34                 $mInterlangs,    //!< Map of language codes to titles
  35                 $mProperties,    //!< Map of arbitrary name to value
  36                 $mDb,            //!< Database connection reference
  37                 $mOptions,       //!< SELECT options to be used (array)
  38                 $mRecursive;     //!< Whether to queue jobs for recursive updates
  39         /**@}}*/
  40
  41         /**
  42          * Constructor
  43          *
  44          * @param $title Title of the page we're updating
  45          * @param $parserOutput ParserOutput: output from a full parse of this page
  46          * @param $recursive Boolean: queue jobs for recursive updates?
  47          */
  48         function __construct( $title, $parserOutput, $recursive = true ) {
  49                 global $wgAntiLockFlags;
  50
  51                 if ( $wgAntiLockFlags & ALF_NO_LINK_LOCK ) {
  52                         $this->mOptions = array();
  53                 } else {
  54                         $this->mOptions = array( 'FOR UPDATE' );
  55                 }
  56                 $this->mDb = wfGetDB( DB_MASTER );
  57
  58                 if ( !is_object( $title ) ) {
  59                         throw new MWException( "The calling convention to LinksUpdate::LinksUpdate() has changed. " .
  60                                 "Please see Article::editUpdates() for an invocation example.\n" );
  61                 }
  62                 $this->mTitle = $title;
  63                 $this->mId = $title->getArticleID();
  64
  65                 $this->mParserOutput = $parserOutput;
  66                 $this->mLinks = $parserOutput->getLinks();
  67                 $this->mImages = $parserOutput->getImages();
  68                 $this->mTemplates = $parserOutput->getTemplates();
  69                 $this->mExternals = $parserOutput->getExternalLinks();
  70                 $this->mCategories = $parserOutput->getCategories();
  71                 $this->mProperties = $parserOutput->getProperties();
  72                 $this->mInterwikis = $parserOutput->getInterwikiLinks();
  73
  74                 # Convert the format of the interlanguage links
  75                 # I didn't want to change it in the ParserOutput, because that array is passed all
  76                 # the way back to the skin, so either a skin API break would be required, or an
  77                 # inefficient back-conversion.
  78                 $ill = $parserOutput->getLanguageLinks();
  79                 $this->mInterlangs = array();
  80                 foreach ( $ill as $link ) {
  81                         list( $key, $title ) = explode( ':', $link, 2 );
  82                         $this->mInterlangs[$key] = $title;
  83                 }
  84
  85                 foreach ( $this->mCategories as &$sortkey ) {
  86                         # If the sortkey is longer then 255 bytes,
  87                         # it truncated by DB, and then doesn't get
  88                         # matched when comparing existing vs current
  89                         # categories, causing bug 25254.
  90                         # Also. substr behaves weird when given "".
  91                         if ( $sortkey !== '' ) {
  92                                 $sortkey = substr( $sortkey, 0, 255 );
  93                         }
  94                 }
  95
  96                 $this->mRecursive = $recursive;
  97
  98                 wfRunHooks( 'LinksUpdateConstructed', array( &$this ) );
  99         }
 100
 101         /**
 102          * Update link tables with outgoing links from an updated article
 103          */
 104         public function doUpdate() {
 105                 global $wgUseDumbLinkUpdate;
 106
 107                 wfRunHooks( 'LinksUpdate', array( &$this ) );
 108                 if ( $wgUseDumbLinkUpdate ) {
 109                         $this->doDumbUpdate();
 110                 } else {
 111                         $this->doIncrementalUpdate();
 112                 }
 113                 wfRunHooks( 'LinksUpdateComplete', array( &$this ) );
 114         }
 115
 116         protected function doIncrementalUpdate() {
 117                 wfProfileIn( __METHOD__ );
 118
 119                 # Page links
 120                 $existing = $this->getExistingLinks();
 121                 $this->incrTableUpdate( 'pagelinks', 'pl', $this->getLinkDeletions( $existing ),
 122                         $this->getLinkInsertions( $existing ) );
 123
 124                 # Image links
 125                 $existing = $this->getExistingImages();
 126
 127                 $imageDeletes = $this->getImageDeletions( $existing );
 128                 $this->incrTableUpdate( 'imagelinks', 'il', $imageDeletes,
 129                         $this->getImageInsertions( $existing ) );
 130
 131                 # Invalidate all image description pages which had links added or removed
 132                 $imageUpdates = $imageDeletes + array_diff_key( $this->mImages, $existing );
 133                 $this->invalidateImageDescriptions( $imageUpdates );
 134
 135                 # External links
 136                 $existing = $this->getExistingExternals();
 137                 $this->incrTableUpdate( 'externallinks', 'el', $this->getExternalDeletions( $existing ),
 138                         $this->getExternalInsertions( $existing ) );
 139
 140                 # Language links
 141                 $existing = $this->getExistingInterlangs();
 142                 $this->incrTableUpdate( 'langlinks', 'll', $this->getInterlangDeletions( $existing ),
 143                         $this->getInterlangInsertions( $existing ) );
 144
 145                 # Inline interwiki links
 146                 $existing = $this->getExistingInterwikis();
 147                 $this->incrTableUpdate( 'iwlinks', 'iwl', $this->getInterwikiDeletions( $existing ),
 148                         $this->getInterwikiInsertions( $existing ) );
 149
 150                 # Template links
 151                 $existing = $this->getExistingTemplates();
 152                 $this->incrTableUpdate( 'templatelinks', 'tl', $this->getTemplateDeletions( $existing ),
 153                         $this->getTemplateInsertions( $existing ) );
 154
 155                 # Category links
 156                 $existing = $this->getExistingCategories();
 157
 158                 $categoryDeletes = $this->getCategoryDeletions( $existing );
 159
 160                 $this->incrTableUpdate( 'categorylinks', 'cl', $categoryDeletes,
 161                         $this->getCategoryInsertions( $existing ) );
 162
 163                 # Invalidate all categories which were added, deleted or changed (set symmetric difference)
 164                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 165                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 166                 $this->invalidateCategories( $categoryUpdates );
 167                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 168
 169                 # Page properties
 170                 $existing = $this->getExistingProperties();
 171
 172                 $propertiesDeletes = $this->getPropertyDeletions( $existing );
 173
 174                 $this->incrTableUpdate( 'page_props', 'pp', $propertiesDeletes,
 175                         $this->getPropertyInsertions( $existing ) );
 176
 177                 # Invalidate the necessary pages
 178                 $changed = $propertiesDeletes + array_diff_assoc( $this->mProperties, $existing );
 179                 $this->invalidateProperties( $changed );
 180
 181                 # Refresh links of all pages including this page
 182                 # This will be in a separate transaction
 183                 if ( $this->mRecursive ) {
 184                         $this->queueRecursiveJobs();
 185                 }
 186
 187                 wfProfileOut( __METHOD__ );
 188         }
 189
 190         /**
 191          * Link update which clears the previous entries and inserts new ones
 192          * May be slower or faster depending on level of lock contention and write speed of DB
 193          * Also useful where link table corruption needs to be repaired, e.g. in refreshLinks.php
 194          */
 195         protected function doDumbUpdate() {
 196                 wfProfileIn( __METHOD__ );
 197
 198                 # Refresh category pages and image description pages
 199                 $existing = $this->getExistingCategories();
 200                 $categoryInserts = array_diff_assoc( $this->mCategories, $existing );
 201                 $categoryDeletes = array_diff_assoc( $existing, $this->mCategories );
 202                 $categoryUpdates = $categoryInserts + $categoryDeletes;
 203                 $existing = $this->getExistingImages();
 204                 $imageUpdates = array_diff_key( $existing, $this->mImages ) + array_diff_key( $this->mImages, $existing );
 205
 206                 $this->dumbTableUpdate( 'pagelinks',     $this->getLinkInsertions(),     'pl_from' );
 207                 $this->dumbTableUpdate( 'imagelinks',    $this->getImageInsertions(),    'il_from' );
 208                 $this->dumbTableUpdate( 'categorylinks', $this->getCategoryInsertions(), 'cl_from' );
 209                 $this->dumbTableUpdate( 'templatelinks', $this->getTemplateInsertions(), 'tl_from' );
 210                 $this->dumbTableUpdate( 'externallinks', $this->getExternalInsertions(), 'el_from' );
 211                 $this->dumbTableUpdate( 'langlinks',     $this->getInterlangInsertions(),'ll_from' );
 212                 $this->dumbTableUpdate( 'iwlinks',       $this->getInterwikiInsertions(),'iwl_from' );
 213                 $this->dumbTableUpdate( 'page_props',    $this->getPropertyInsertions(), 'pp_page' );
 214
 215                 # Update the cache of all the category pages and image description
 216                 # pages which were changed, and fix the category table count
 217                 $this->invalidateCategories( $categoryUpdates );
 218                 $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
 219                 $this->invalidateImageDescriptions( $imageUpdates );
 220
 221                 # Refresh links of all pages including this page
 222                 # This will be in a separate transaction
 223                 if ( $this->mRecursive ) {
 224                         $this->queueRecursiveJobs();
 225                 }
 226
 227                 wfProfileOut( __METHOD__ );
 228         }
 229
 230         function queueRecursiveJobs() {
 231                 global $wgUpdateRowsPerJob;
 232                 wfProfileIn( __METHOD__ );
 233
 234                 $cache = $this->mTitle->getBacklinkCache();
 235                 $batches = $cache->partition( 'templatelinks', $wgUpdateRowsPerJob );
 236                 if ( !$batches ) {
 237                         wfProfileOut( __METHOD__ );
 238                         return;
 239                 }
 240                 $jobs = array();
 241                 foreach ( $batches as $batch ) {
 242                         list( $start, $end ) = $batch;
 243                         $params = array(
 244                                 'table' => 'templatelinks',
 245                                 'start' => $start,
 246                                 'end' => $end,
 247                         );
 248                         $jobs[] = new RefreshLinksJob2( $this->mTitle, $params );
 249                 }
 250                 Job::batchInsert( $jobs );
 251
 252                 wfProfileOut( __METHOD__ );
 253         }
 254
 255         /**
 256          * Invalidate the cache of a list of pages from a single namespace
 257          *
 258          * @param $namespace Integer
 259          * @param $dbkeys Array
 260          */
 261         function invalidatePages( $namespace, $dbkeys ) {
 262                 if ( !count( $dbkeys ) ) {
 263                         return;
 264                 }
 265
 266                 /**
 267                  * Determine which pages need to be updated
 268                  * This is necessary to prevent the job queue from smashing the DB with
 269                  * large numbers of concurrent invalidations of the same page
 270                  */
 271                 $now = $this->mDb->timestamp();
 272                 $ids = array();
 273                 $res = $this->mDb->select( 'page', array( 'page_id' ),
 274                         array(
 275                                 'page_namespace' => $namespace,
 276                                 'page_title IN (' . $this->mDb->makeList( $dbkeys ) . ')',
 277                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 278                         ), __METHOD__
 279                 );
 280                 foreach ( $res as $row ) {
 281                         $ids[] = $row->page_id;
 282                 }
 283                 if ( !count( $ids ) ) {
 284                         return;
 285                 }
 286
 287                 /**
 288                  * Do the update
 289                  * We still need the page_touched condition, in case the row has changed since
 290                  * the non-locking select above.
 291                  */
 292                 $this->mDb->update( 'page', array( 'page_touched' => $now ),
 293                         array(
 294                                 'page_id IN (' . $this->mDb->makeList( $ids ) . ')',
 295                                 'page_touched < ' . $this->mDb->addQuotes( $now )
 296                         ), __METHOD__
 297                 );
 298         }
 299
 300         function invalidateCategories( $cats ) {
 301                 $this->invalidatePages( NS_CATEGORY, array_keys( $cats ) );
 302         }
 303
 304         /**
 305          * Update all the appropriate counts in the category table.
 306          * @param $added associative array of category name => sort key
 307          * @param $deleted associative array of category name => sort key
 308          */
 309         function updateCategoryCounts( $added, $deleted ) {
 310                 $a = new Article($this->mTitle);
 311                 $a->updateCategoryCounts(
 312                         array_keys( $added ), array_keys( $deleted )
 313                 );
 314         }
 315
 316         function invalidateImageDescriptions( $images ) {
 317                 $this->invalidatePages( NS_FILE, array_keys( $images ) );
 318         }
 319
 320         function dumbTableUpdate( $table, $insertions, $fromField ) {
 321                 $this->mDb->delete( $table, array( $fromField => $this->mId ), __METHOD__ );
 322                 if ( count( $insertions ) ) {
 323                         # The link array was constructed without FOR UPDATE, so there may
 324                         # be collisions.  This may cause minor link table inconsistencies,
 325                         # which is better than crippling the site with lock contention.
 326                         $this->mDb->insert( $table, $insertions, __METHOD__, array( 'IGNORE' ) );
 327                 }
 328         }
 329
 330         /**
 331          * Update a table by doing a delete query then an insert query
 332          * @private
 333          */
 334         function incrTableUpdate( $table, $prefix, $deletions, $insertions ) {
 335                 if ( $table == 'page_props' ) {
 336                         $fromField = 'pp_page';
 337                 } else {
 338                         $fromField = "{$prefix}_from";
 339                 }
 340                 $where = array( $fromField => $this->mId );
 341                 if ( $table == 'pagelinks' || $table == 'templatelinks' || $table == 'iwlinks' ) {
 342                         if ( $table == 'iwlinks' ) {
 343                                 $baseKey = 'iwl_prefix';
 344                         } else {
 345                                 $baseKey = "{$prefix}_namespace";
 346                         }
 347                         $clause = $this->mDb->makeWhereFrom2d( $deletions, $baseKey, "{$prefix}_title" );
 348                         if ( $clause ) {
 349                                 $where[] = $clause;
 350                         } else {
 351                                 $where = false;
 352                         }
 353                 } else {
 354                         if ( $table == 'langlinks' ) {
 355                                 $toField = 'll_lang';
 356                         } elseif ( $table == 'page_props' ) {
 357                                 $toField = 'pp_propname';
 358                         } else {
 359                                 $toField = $prefix . '_to';
 360                         }
 361                         if ( count( $deletions ) ) {
 362                                 $where[] = "$toField IN (" . $this->mDb->makeList( array_keys( $deletions ) ) . ')';
 363                         } else {
 364                                 $where = false;
 365                         }
 366                 }
 367                 if ( $where ) {
 368                         $this->mDb->delete( $table, $where, __METHOD__ );
 369                 }
 370                 if ( count( $insertions ) ) {
 371                         $this->mDb->insert( $table, $insertions, __METHOD__, 'IGNORE' );
 372                 }
 373         }
 374
 375
 376         /**
 377          * Get an array of pagelinks insertions for passing to the DB
 378          * Skips the titles specified by the 2-D array $existing
 379          * @private
 380          */
 381         function getLinkInsertions( $existing = array() ) {
 382                 $arr = array();
 383                 foreach( $this->mLinks as $ns => $dbkeys ) {
 384                         $diffs = isset( $existing[$ns] )
 385                                 ? array_diff_key( $dbkeys, $existing[$ns] )
 386                                 : $dbkeys;
 387                         foreach ( $diffs as $dbk => $id ) {
 388                                 $arr[] = array(
 389                                         'pl_from'      => $this->mId,
 390                                         'pl_namespace' => $ns,
 391                                         'pl_title'     => $dbk
 392                                 );
 393                         }
 394                 }
 395                 return $arr;
 396         }
 397
 398         /**
 399          * Get an array of template insertions. Like getLinkInsertions()
 400          * @private
 401          */
 402         function getTemplateInsertions( $existing = array() ) {
 403                 $arr = array();
 404                 foreach( $this->mTemplates as $ns => $dbkeys ) {
 405                         $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
 406                         foreach ( $diffs as $dbk => $id ) {
 407                                 $arr[] = array(
 408                                         'tl_from'      => $this->mId,
 409                                         'tl_namespace' => $ns,
 410                                         'tl_title'     => $dbk
 411                                 );
 412                         }
 413                 }
 414                 return $arr;
 415         }
 416
 417         /**
 418          * Get an array of image insertions
 419          * Skips the names specified in $existing
 420          * @private
 421          */
 422         function getImageInsertions( $existing = array() ) {
 423                 $arr = array();
 424                 $diffs = array_diff_key( $this->mImages, $existing );
 425                 foreach( $diffs as $iname => $dummy ) {
 426                         $arr[] = array(
 427                                 'il_from' => $this->mId,
 428                                 'il_to'   => $iname
 429                         );
 430                 }
 431                 return $arr;
 432         }
 433
 434         /**
 435          * Get an array of externallinks insertions. Skips the names specified in $existing
 436          * @private
 437          */
 438         function getExternalInsertions( $existing = array() ) {
 439                 $arr = array();
 440                 $diffs = array_diff_key( $this->mExternals, $existing );
 441                 foreach( $diffs as $url => $dummy ) {
 442                         $arr[] = array(
 443                                 'el_from'   => $this->mId,
 444                                 'el_to'     => $url,
 445                                 'el_index'  => wfMakeUrlIndex( $url ),
 446                         );
 447                 }
 448                 return $arr;
 449         }
 450
 451         /**
 452          * Get an array of category insertions
 453          *
 454          * @param $existing Array mapping existing category names to sort keys. If both
 455          * match a link in $this, the link will be omitted from the output
 456          * @private
 457          */
 458         function getCategoryInsertions( $existing = array() ) {
 459                 global $wgContLang, $wgCategoryCollation;
 460                 $diffs = array_diff_assoc( $this->mCategories, $existing );
 461                 $arr = array();
 462                 foreach ( $diffs as $name => $prefix ) {
 463                         $nt = Title::makeTitleSafe( NS_CATEGORY, $name );
 464                         $wgContLang->findVariantLink( $name, $nt, true );
 465
 466                         if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
 467                                 $type = 'subcat';
 468                         } elseif ( $this->mTitle->getNamespace() == NS_FILE ) {
 469                                 $type = 'file';
 470                         } else {
 471                                 $type = 'page';
 472                         }
 473
 474                         # Treat custom sortkeys as a prefix, so that if multiple
 475                         # things are forced to sort as '*' or something, they'll
 476                         # sort properly in the category rather than in page_id
 477                         # order or such.
 478                         $sortkey = Collation::singleton()->getSortKey(
 479                                 $this->mTitle->getCategorySortkey( $prefix ) );
 480
 481                         $arr[] = array(
 482                                 'cl_from'    => $this->mId,
 483                                 'cl_to'      => $name,
 484                                 'cl_sortkey' => $sortkey,
 485                                 'cl_timestamp' => $this->mDb->timestamp(),
 486                                 'cl_sortkey_prefix' => $prefix,
 487                                 'cl_collation' => $wgCategoryCollation,
 488                                 'cl_type' => $type,
 489                         );
 490                 }
 491                 return $arr;
 492         }
 493
 494         /**
 495          * Get an array of interlanguage link insertions
 496          *
 497          * @param $existing Array mapping existing language codes to titles
 498          * @private
 499          */
 500         function getInterlangInsertions( $existing = array() ) {
 501                 $diffs = array_diff_assoc( $this->mInterlangs, $existing );
 502                 $arr = array();
 503                 foreach( $diffs as $lang => $title ) {
 504                         $arr[] = array(
 505                                 'll_from'  => $this->mId,
 506                                 'll_lang'  => $lang,
 507                                 'll_title' => $title
 508                         );
 509                 }
 510                 return $arr;
 511         }
 512
 513         /**
 514          * Get an array of page property insertions
 515          */
 516         function getPropertyInsertions( $existing = array() ) {
 517                 $diffs = array_diff_assoc( $this->mProperties, $existing );
 518                 $arr = array();
 519                 foreach ( $diffs as $name => $value ) {
 520                         $arr[] = array(
 521                                 'pp_page'      => $this->mId,
 522                                 'pp_propname'  => $name,
 523                                 'pp_value'     => $value,
 524                         );
 525                 }
 526                 return $arr;
 527         }
 528
 529         /**
 530          * Get an array of interwiki insertions for passing to the DB
 531          * Skips the titles specified by the 2-D array $existing
 532          * @private
 533          */
 534         function getInterwikiInsertions( $existing = array() ) {
 535                 $arr = array();
 536                 foreach( $this->mInterwikis as $prefix => $dbkeys ) {
 537                         $diffs = isset( $existing[$prefix] ) ? array_diff_key( $dbkeys, $existing[$prefix] ) : $dbkeys;
 538                         foreach ( $diffs as $dbk => $id ) {
 539                                 $arr[] = array(
 540                                         'iwl_from'   => $this->mId,
 541                                         'iwl_prefix' => $prefix,
 542                                         'iwl_title'  => $dbk
 543                                 );
 544                         }
 545                 }
 546                 return $arr;
 547         }
 548
 549         /**
 550          * Given an array of existing links, returns those links which are not in $this
 551          * and thus should be deleted.
 552          * @private
 553          */
 554         function getLinkDeletions( $existing ) {
 555                 $del = array();
 556                 foreach ( $existing as $ns => $dbkeys ) {
 557                         if ( isset( $this->mLinks[$ns] ) ) {
 558                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mLinks[$ns] );
 559                         } else {
 560                                 $del[$ns] = $existing[$ns];
 561                         }
 562                 }
 563                 return $del;
 564         }
 565
 566         /**
 567          * Given an array of existing templates, returns those templates which are not in $this
 568          * and thus should be deleted.
 569          * @private
 570          */
 571         function getTemplateDeletions( $existing ) {
 572                 $del = array();
 573                 foreach ( $existing as $ns => $dbkeys ) {
 574                         if ( isset( $this->mTemplates[$ns] ) ) {
 575                                 $del[$ns] = array_diff_key( $existing[$ns], $this->mTemplates[$ns] );
 576                         } else {
 577                                 $del[$ns] = $existing[$ns];
 578                         }
 579                 }
 580                 return $del;
 581         }
 582
 583         /**
 584          * Given an array of existing images, returns those images which are not in $this
 585          * and thus should be deleted.
 586          * @private
 587          */
 588         function getImageDeletions( $existing ) {
 589                 return array_diff_key( $existing, $this->mImages );
 590         }
 591
 592         /**
 593          * Given an array of existing external links, returns those links which are not
 594          * in $this and thus should be deleted.
 595          * @private
 596          */
 597         function getExternalDeletions( $existing ) {
 598                 return array_diff_key( $existing, $this->mExternals );
 599         }
 600
 601         /**
 602          * Given an array of existing categories, returns those categories which are not in $this
 603          * and thus should be deleted.
 604          * @private
 605          */
 606         function getCategoryDeletions( $existing ) {
 607                 return array_diff_assoc( $existing, $this->mCategories );
 608         }
 609
 610         /**
 611          * Given an array of existing interlanguage links, returns those links which are not
 612          * in $this and thus should be deleted.
 613          * @private
 614          */
 615         function getInterlangDeletions( $existing ) {
 616                 return array_diff_assoc( $existing, $this->mInterlangs );
 617         }
 618
 619         /**
 620          * Get array of properties which should be deleted.
 621          * @private
 622          */
 623         function getPropertyDeletions( $existing ) {
 624                 return array_diff_assoc( $existing, $this->mProperties );
 625         }
 626
 627         /**
 628          * Given an array of existing interwiki links, returns those links which are not in $this
 629          * and thus should be deleted.
 630          * @private
 631          */
 632         function getInterwikiDeletions( $existing ) {
 633                 $del = array();
 634                 foreach ( $existing as $prefix => $dbkeys ) {
 635                         if ( isset( $this->mInterwikis[$prefix] ) ) {
 636                                 $del[$prefix] = array_diff_key( $existing[$prefix], $this->mInterwikis[$prefix] );
 637                         } else {
 638                                 $del[$prefix] = $existing[$prefix];
 639                         }
 640                 }
 641                 return $del;
 642         }
 643
 644         /**
 645          * Get an array of existing links, as a 2-D array
 646          * @private
 647          */
 648         function getExistingLinks() {
 649                 $res = $this->mDb->select( 'pagelinks', array( 'pl_namespace', 'pl_title' ),
 650                         array( 'pl_from' => $this->mId ), __METHOD__, $this->mOptions );
 651                 $arr = array();
 652                 foreach ( $res as $row ) {
 653                         if ( !isset( $arr[$row->pl_namespace] ) ) {
 654                                 $arr[$row->pl_namespace] = array();
 655                         }
 656                         $arr[$row->pl_namespace][$row->pl_title] = 1;
 657                 }
 658                 return $arr;
 659         }
 660
 661         /**
 662          * Get an array of existing templates, as a 2-D array
 663          * @private
 664          */
 665         function getExistingTemplates() {
 666                 $res = $this->mDb->select( 'templatelinks', array( 'tl_namespace', 'tl_title' ),
 667                         array( 'tl_from' => $this->mId ), __METHOD__, $this->mOptions );
 668                 $arr = array();
 669                 foreach ( $res as $row ) {
 670                         if ( !isset( $arr[$row->tl_namespace] ) ) {
 671                                 $arr[$row->tl_namespace] = array();
 672                         }
 673                         $arr[$row->tl_namespace][$row->tl_title] = 1;
 674                 }
 675                 return $arr;
 676         }
 677
 678         /**
 679          * Get an array of existing images, image names in the keys
 680          * @private
 681          */
 682         function getExistingImages() {
 683                 $res = $this->mDb->select( 'imagelinks', array( 'il_to' ),
 684                         array( 'il_from' => $this->mId ), __METHOD__, $this->mOptions );
 685                 $arr = array();
 686                 foreach ( $res as $row ) {
 687                         $arr[$row->il_to] = 1;
 688                 }
 689                 return $arr;
 690         }
 691
 692         /**
 693          * Get an array of existing external links, URLs in the keys
 694          * @private
 695          */
 696         function getExistingExternals() {
 697                 $res = $this->mDb->select( 'externallinks', array( 'el_to' ),
 698                         array( 'el_from' => $this->mId ), __METHOD__, $this->mOptions );
 699                 $arr = array();
 700                 foreach ( $res as $row ) {
 701                         $arr[$row->el_to] = 1;
 702                 }
 703                 return $arr;
 704         }
 705
 706         /**
 707          * Get an array of existing categories, with the name in the key and sort key in the value.
 708          * @private
 709          */
 710         function getExistingCategories() {
 711                 $res = $this->mDb->select( 'categorylinks', array( 'cl_to', 'cl_sortkey_prefix' ),
 712                         array( 'cl_from' => $this->mId ), __METHOD__, $this->mOptions );
 713                 $arr = array();
 714                 foreach ( $res as $row ) {
 715                         $arr[$row->cl_to] = $row->cl_sortkey_prefix;
 716                 }
 717                 return $arr;
 718         }
 719
 720         /**
 721          * Get an array of existing interlanguage links, with the language code in the key and the
 722          * title in the value.
 723          * @private
 724          */
 725         function getExistingInterlangs() {
 726                 $res = $this->mDb->select( 'langlinks', array( 'll_lang', 'll_title' ),
 727                         array( 'll_from' => $this->mId ), __METHOD__, $this->mOptions );
 728                 $arr = array();
 729                 foreach ( $res as $row ) {
 730                         $arr[$row->ll_lang] = $row->ll_title;
 731                 }
 732                 return $arr;
 733         }
 734
 735         /**
 736          * Get an array of existing inline interwiki links, as a 2-D array
 737          * @return array (prefix => array(dbkey => 1))
 738          */
 739         protected function getExistingInterwikis() {
 740                 $res = $this->mDb->select( 'iwlinks', array( 'iwl_prefix', 'iwl_title' ),
 741                         array( 'iwl_from' => $this->mId ), __METHOD__, $this->mOptions );
 742                 $arr = array();
 743                 foreach ( $res as $row ) {
 744                         if ( !isset( $arr[$row->iwl_prefix] ) ) {
 745                                 $arr[$row->iwl_prefix] = array();
 746                         }
 747                         $arr[$row->iwl_prefix][$row->iwl_title] = 1;
 748                 }
 749                 return $arr;
 750         }
 751
 752         /**
 753          * Get an array of existing categories, with the name in the key and sort key in the value.
 754          * @private
 755          */
 756         function getExistingProperties() {
 757                 $res = $this->mDb->select( 'page_props', array( 'pp_propname', 'pp_value' ),
 758                         array( 'pp_page' => $this->mId ), __METHOD__, $this->mOptions );
 759                 $arr = array();
 760                 foreach ( $res as $row ) {
 761                         $arr[$row->pp_propname] = $row->pp_value;
 762                 }
 763                 return $arr;
 764         }
 765
 766
 767         /**
 768          * Return the title object of the page being updated
 769          */
 770         function getTitle() {
 771                 return $this->mTitle;
 772         }
 773
 774         /**
 775          * Return the list of images used as generated by the parser
 776          */
 777         public function getImages() {
 778                 return $this->mImages;
 779         }
 780
 781         /**
 782          * Invalidate any necessary link lists related to page property changes
 783          */
 784         function invalidateProperties( $changed ) {
 785                 global $wgPagePropLinkInvalidations;
 786
 787                 foreach ( $changed as $name => $value ) {
 788                         if ( isset( $wgPagePropLinkInvalidations[$name] ) ) {
 789                                 $inv = $wgPagePropLinkInvalidations[$name];
 790                                 if ( !is_array( $inv ) ) {
 791                                         $inv = array( $inv );
 792                                 }
 793                                 foreach ( $inv as $table ) {
 794                                         $update = new HTMLCacheUpdate( $this->mTitle, $table );
 795                                         $update->doUpdate();
 796                                 }
 797                         }
 798                 }
 799         }
 800 }