includes/LinksUpdate.php

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