]> scripts.mit.edu Git - autoinstallsdev/mediawiki.git/blobdiff - includes/deferred/LinksUpdate.php
MediaWiki 1.30.2
[autoinstallsdev/mediawiki.git] / includes / deferred / LinksUpdate.php
diff --git a/includes/deferred/LinksUpdate.php b/includes/deferred/LinksUpdate.php
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+<?php
+/**
+ * Updater for link tracking tables after a page edit.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+use Wikimedia\Rdbms\IDatabase;
+use MediaWiki\MediaWikiServices;
+use Wikimedia\ScopedCallback;
+
+/**
+ * Class the manages updates of *_link tables as well as similar extension-managed tables
+ *
+ * @note: LinksUpdate is managed by DeferredUpdates::execute(). Do not run this in a transaction.
+ *
+ * See docs/deferred.txt
+ */
+class LinksUpdate extends DataUpdate implements EnqueueableDataUpdate {
+       // @todo make members protected, but make sure extensions don't break
+
+       /** @var int Page ID of the article linked from */
+       public $mId;
+
+       /** @var Title Title object of the article linked from */
+       public $mTitle;
+
+       /** @var ParserOutput */
+       public $mParserOutput;
+
+       /** @var array Map of title strings to IDs for the links in the document */
+       public $mLinks;
+
+       /** @var array DB keys of the images used, in the array key only */
+       public $mImages;
+
+       /** @var array Map of title strings to IDs for the template references, including broken ones */
+       public $mTemplates;
+
+       /** @var array URLs of external links, array key only */
+       public $mExternals;
+
+       /** @var array Map of category names to sort keys */
+       public $mCategories;
+
+       /** @var array Map of language codes to titles */
+       public $mInterlangs;
+
+       /** @var array 2-D map of (prefix => DBK => 1) */
+       public $mInterwikis;
+
+       /** @var array Map of arbitrary name to value */
+       public $mProperties;
+
+       /** @var bool Whether to queue jobs for recursive updates */
+       public $mRecursive;
+
+       /** @var Revision Revision for which this update has been triggered */
+       private $mRevision;
+
+       /**
+        * @var null|array Added links if calculated.
+        */
+       private $linkInsertions = null;
+
+       /**
+        * @var null|array Deleted links if calculated.
+        */
+       private $linkDeletions = null;
+
+       /**
+        * @var null|array Added properties if calculated.
+        */
+       private $propertyInsertions = null;
+
+       /**
+        * @var null|array Deleted properties if calculated.
+        */
+       private $propertyDeletions = null;
+
+       /**
+        * @var User|null
+        */
+       private $user;
+
+       /** @var IDatabase */
+       private $db;
+
+       /**
+        * @param Title $title Title of the page we're updating
+        * @param ParserOutput $parserOutput Output from a full parse of this page
+        * @param bool $recursive Queue jobs for recursive updates?
+        * @throws MWException
+        */
+       function __construct( Title $title, ParserOutput $parserOutput, $recursive = true ) {
+               parent::__construct();
+
+               $this->mTitle = $title;
+               $this->mId = $title->getArticleID( Title::GAID_FOR_UPDATE );
+
+               if ( !$this->mId ) {
+                       throw new InvalidArgumentException(
+                               "The Title object yields no ID. Perhaps the page doesn't exist?"
+                       );
+               }
+
+               $this->mParserOutput = $parserOutput;
+
+               $this->mLinks = $parserOutput->getLinks();
+               $this->mImages = $parserOutput->getImages();
+               $this->mTemplates = $parserOutput->getTemplates();
+               $this->mExternals = $parserOutput->getExternalLinks();
+               $this->mCategories = $parserOutput->getCategories();
+               $this->mProperties = $parserOutput->getProperties();
+               $this->mInterwikis = $parserOutput->getInterwikiLinks();
+
+               # Convert the format of the interlanguage links
+               # I didn't want to change it in the ParserOutput, because that array is passed all
+               # the way back to the skin, so either a skin API break would be required, or an
+               # inefficient back-conversion.
+               $ill = $parserOutput->getLanguageLinks();
+               $this->mInterlangs = [];
+               foreach ( $ill as $link ) {
+                       list( $key, $title ) = explode( ':', $link, 2 );
+                       $this->mInterlangs[$key] = $title;
+               }
+
+               foreach ( $this->mCategories as &$sortkey ) {
+                       # If the sortkey is longer then 255 bytes,
+                       # it truncated by DB, and then doesn't get
+                       # matched when comparing existing vs current
+                       # categories, causing T27254.
+                       # Also. substr behaves weird when given "".
+                       if ( $sortkey !== '' ) {
+                               $sortkey = substr( $sortkey, 0, 255 );
+                       }
+               }
+
+               $this->mRecursive = $recursive;
+
+               // Avoid PHP 7.1 warning from passing $this by reference
+               $linksUpdate = $this;
+               Hooks::run( 'LinksUpdateConstructed', [ &$linksUpdate ] );
+       }
+
+       /**
+        * Update link tables with outgoing links from an updated article
+        *
+        * @note: this is managed by DeferredUpdates::execute(). Do not run this in a transaction.
+        */
+       public function doUpdate() {
+               if ( $this->ticket ) {
+                       // Make sure all links update threads see the changes of each other.
+                       // This handles the case when updates have to batched into several COMMITs.
+                       $scopedLock = self::acquirePageLock( $this->getDB(), $this->mId );
+               }
+
+               // Avoid PHP 7.1 warning from passing $this by reference
+               $linksUpdate = $this;
+               Hooks::run( 'LinksUpdate', [ &$linksUpdate ] );
+               $this->doIncrementalUpdate();
+
+               // Commit and release the lock (if set)
+               ScopedCallback::consume( $scopedLock );
+               // Run post-commit hooks without DBO_TRX
+               $this->getDB()->onTransactionIdle(
+                       function () {
+                               // Avoid PHP 7.1 warning from passing $this by reference
+                               $linksUpdate = $this;
+                               Hooks::run( 'LinksUpdateComplete', [ &$linksUpdate, $this->ticket ] );
+                       },
+                       __METHOD__
+               );
+       }
+
+       /**
+        * Acquire a lock for performing link table updates for a page on a DB
+        *
+        * @param IDatabase $dbw
+        * @param int $pageId
+        * @param string $why One of (job, atomicity)
+        * @return ScopedCallback
+        * @throws RuntimeException
+        * @since 1.27
+        */
+       public static function acquirePageLock( IDatabase $dbw, $pageId, $why = 'atomicity' ) {
+               $key = "LinksUpdate:$why:pageid:$pageId";
+               $scopedLock = $dbw->getScopedLockAndFlush( $key, __METHOD__, 15 );
+               if ( !$scopedLock ) {
+                       throw new RuntimeException( "Could not acquire lock '$key'." );
+               }
+
+               return $scopedLock;
+       }
+
+       protected function doIncrementalUpdate() {
+               # Page links
+               $existingPL = $this->getExistingLinks();
+               $this->linkDeletions = $this->getLinkDeletions( $existingPL );
+               $this->linkInsertions = $this->getLinkInsertions( $existingPL );
+               $this->incrTableUpdate( 'pagelinks', 'pl', $this->linkDeletions, $this->linkInsertions );
+
+               # Image links
+               $existingIL = $this->getExistingImages();
+               $imageDeletes = $this->getImageDeletions( $existingIL );
+               $this->incrTableUpdate(
+                       'imagelinks',
+                       'il',
+                       $imageDeletes,
+                       $this->getImageInsertions( $existingIL ) );
+
+               # Invalidate all image description pages which had links added or removed
+               $imageUpdates = $imageDeletes + array_diff_key( $this->mImages, $existingIL );
+               $this->invalidateImageDescriptions( $imageUpdates );
+
+               # External links
+               $existingEL = $this->getExistingExternals();
+               $this->incrTableUpdate(
+                       'externallinks',
+                       'el',
+                       $this->getExternalDeletions( $existingEL ),
+                       $this->getExternalInsertions( $existingEL ) );
+
+               # Language links
+               $existingLL = $this->getExistingInterlangs();
+               $this->incrTableUpdate(
+                       'langlinks',
+                       'll',
+                       $this->getInterlangDeletions( $existingLL ),
+                       $this->getInterlangInsertions( $existingLL ) );
+
+               # Inline interwiki links
+               $existingIW = $this->getExistingInterwikis();
+               $this->incrTableUpdate(
+                       'iwlinks',
+                       'iwl',
+                       $this->getInterwikiDeletions( $existingIW ),
+                       $this->getInterwikiInsertions( $existingIW ) );
+
+               # Template links
+               $existingTL = $this->getExistingTemplates();
+               $this->incrTableUpdate(
+                       'templatelinks',
+                       'tl',
+                       $this->getTemplateDeletions( $existingTL ),
+                       $this->getTemplateInsertions( $existingTL ) );
+
+               # Category links
+               $existingCL = $this->getExistingCategories();
+               $categoryDeletes = $this->getCategoryDeletions( $existingCL );
+               $this->incrTableUpdate(
+                       'categorylinks',
+                       'cl',
+                       $categoryDeletes,
+                       $this->getCategoryInsertions( $existingCL ) );
+               $categoryInserts = array_diff_assoc( $this->mCategories, $existingCL );
+               $categoryUpdates = $categoryInserts + $categoryDeletes;
+
+               # Page properties
+               $existingPP = $this->getExistingProperties();
+               $this->propertyDeletions = $this->getPropertyDeletions( $existingPP );
+               $this->incrTableUpdate(
+                       'page_props',
+                       'pp',
+                       $this->propertyDeletions,
+                       $this->getPropertyInsertions( $existingPP ) );
+
+               # Invalidate the necessary pages
+               $this->propertyInsertions = array_diff_assoc( $this->mProperties, $existingPP );
+               $changed = $this->propertyDeletions + $this->propertyInsertions;
+               $this->invalidateProperties( $changed );
+
+               # Invalidate all categories which were added, deleted or changed (set symmetric difference)
+               $this->invalidateCategories( $categoryUpdates );
+               $this->updateCategoryCounts( $categoryInserts, $categoryDeletes );
+
+               # Refresh links of all pages including this page
+               # This will be in a separate transaction
+               if ( $this->mRecursive ) {
+                       $this->queueRecursiveJobs();
+               }
+
+               # Update the links table freshness for this title
+               $this->updateLinksTimestamp();
+       }
+
+       /**
+        * Queue recursive jobs for this page
+        *
+        * Which means do LinksUpdate on all pages that include the current page,
+        * using the job queue.
+        */
+       protected function queueRecursiveJobs() {
+               self::queueRecursiveJobsForTable( $this->mTitle, 'templatelinks' );
+               if ( $this->mTitle->getNamespace() == NS_FILE ) {
+                       // Process imagelinks in case the title is or was a redirect
+                       self::queueRecursiveJobsForTable( $this->mTitle, 'imagelinks' );
+               }
+
+               $bc = $this->mTitle->getBacklinkCache();
+               // Get jobs for cascade-protected backlinks for a high priority queue.
+               // If meta-templates change to using a new template, the new template
+               // should be implicitly protected as soon as possible, if applicable.
+               // These jobs duplicate a subset of the above ones, but can run sooner.
+               // Which ever runs first generally no-ops the other one.
+               $jobs = [];
+               foreach ( $bc->getCascadeProtectedLinks() as $title ) {
+                       $jobs[] = RefreshLinksJob::newPrioritized( $title, [] );
+               }
+               JobQueueGroup::singleton()->push( $jobs );
+       }
+
+       /**
+        * Queue a RefreshLinks job for any table.
+        *
+        * @param Title $title Title to do job for
+        * @param string $table Table to use (e.g. 'templatelinks')
+        */
+       public static function queueRecursiveJobsForTable( Title $title, $table ) {
+               if ( $title->getBacklinkCache()->hasLinks( $table ) ) {
+                       $job = new RefreshLinksJob(
+                               $title,
+                               [
+                                       'table' => $table,
+                                       'recursive' => true,
+                               ] + Job::newRootJobParams( // "overall" refresh links job info
+                                       "refreshlinks:{$table}:{$title->getPrefixedText()}"
+                               )
+                       );
+
+                       JobQueueGroup::singleton()->push( $job );
+               }
+       }
+
+       /**
+        * @param array $cats
+        */
+       private function invalidateCategories( $cats ) {
+               PurgeJobUtils::invalidatePages( $this->getDB(), NS_CATEGORY, array_keys( $cats ) );
+       }
+
+       /**
+        * Update all the appropriate counts in the category table.
+        * @param array $added Associative array of category name => sort key
+        * @param array $deleted Associative array of category name => sort key
+        */
+       private function updateCategoryCounts( array $added, array $deleted ) {
+               global $wgUpdateRowsPerQuery;
+
+               if ( !$added && !$deleted ) {
+                       return;
+               }
+
+               $domainId = $this->getDB()->getDomainID();
+               $wp = WikiPage::factory( $this->mTitle );
+               $lbf = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
+               // T163801: try to release any row locks to reduce contention
+               $lbf->commitAndWaitForReplication( __METHOD__, $this->ticket, [ 'domain' => $domainId ] );
+
+               foreach ( array_chunk( array_keys( $added ), $wgUpdateRowsPerQuery ) as $addBatch ) {
+                       $wp->updateCategoryCounts( $addBatch, [], $this->mId );
+                       $lbf->commitAndWaitForReplication(
+                               __METHOD__, $this->ticket, [ 'domain' => $domainId ] );
+               }
+
+               foreach ( array_chunk( array_keys( $deleted ), $wgUpdateRowsPerQuery ) as $deleteBatch ) {
+                       $wp->updateCategoryCounts( [], $deleteBatch, $this->mId );
+                       $lbf->commitAndWaitForReplication(
+                               __METHOD__, $this->ticket, [ 'domain' => $domainId ] );
+               }
+       }
+
+       /**
+        * @param array $images
+        */
+       private function invalidateImageDescriptions( $images ) {
+               PurgeJobUtils::invalidatePages( $this->getDB(), NS_FILE, array_keys( $images ) );
+       }
+
+       /**
+        * Update a table by doing a delete query then an insert query
+        * @param string $table Table name
+        * @param string $prefix Field name prefix
+        * @param array $deletions
+        * @param array $insertions Rows to insert
+        */
+       private function incrTableUpdate( $table, $prefix, $deletions, $insertions ) {
+               $services = MediaWikiServices::getInstance();
+               $bSize = $services->getMainConfig()->get( 'UpdateRowsPerQuery' );
+               $lbf = $services->getDBLoadBalancerFactory();
+
+               if ( $table === 'page_props' ) {
+                       $fromField = 'pp_page';
+               } else {
+                       $fromField = "{$prefix}_from";
+               }
+
+               $deleteWheres = []; // list of WHERE clause arrays for each DB delete() call
+               if ( $table === 'pagelinks' || $table === 'templatelinks' || $table === 'iwlinks' ) {
+                       $baseKey = ( $table === 'iwlinks' ) ? 'iwl_prefix' : "{$prefix}_namespace";
+
+                       $curBatchSize = 0;
+                       $curDeletionBatch = [];
+                       $deletionBatches = [];
+                       foreach ( $deletions as $ns => $dbKeys ) {
+                               foreach ( $dbKeys as $dbKey => $unused ) {
+                                       $curDeletionBatch[$ns][$dbKey] = 1;
+                                       if ( ++$curBatchSize >= $bSize ) {
+                                               $deletionBatches[] = $curDeletionBatch;
+                                               $curDeletionBatch = [];
+                                               $curBatchSize = 0;
+                                       }
+                               }
+                       }
+                       if ( $curDeletionBatch ) {
+                               $deletionBatches[] = $curDeletionBatch;
+                       }
+
+                       foreach ( $deletionBatches as $deletionBatch ) {
+                               $deleteWheres[] = [
+                                       $fromField => $this->mId,
+                                       $this->getDB()->makeWhereFrom2d( $deletionBatch, $baseKey, "{$prefix}_title" )
+                               ];
+                       }
+               } else {
+                       if ( $table === 'langlinks' ) {
+                               $toField = 'll_lang';
+                       } elseif ( $table === 'page_props' ) {
+                               $toField = 'pp_propname';
+                       } else {
+                               $toField = $prefix . '_to';
+                       }
+
+                       $deletionBatches = array_chunk( array_keys( $deletions ), $bSize );
+                       foreach ( $deletionBatches as $deletionBatch ) {
+                               $deleteWheres[] = [ $fromField => $this->mId, $toField => $deletionBatch ];
+                       }
+               }
+
+               $domainId = $this->getDB()->getDomainID();
+
+               foreach ( $deleteWheres as $deleteWhere ) {
+                       $this->getDB()->delete( $table, $deleteWhere, __METHOD__ );
+                       $lbf->commitAndWaitForReplication(
+                               __METHOD__, $this->ticket, [ 'domain' => $domainId ]
+                       );
+               }
+
+               $insertBatches = array_chunk( $insertions, $bSize );
+               foreach ( $insertBatches as $insertBatch ) {
+                       $this->getDB()->insert( $table, $insertBatch, __METHOD__, 'IGNORE' );
+                       $lbf->commitAndWaitForReplication(
+                               __METHOD__, $this->ticket, [ 'domain' => $domainId ]
+                       );
+               }
+
+               if ( count( $insertions ) ) {
+                       Hooks::run( 'LinksUpdateAfterInsert', [ $this, $table, $insertions ] );
+               }
+       }
+
+       /**
+        * Get an array of pagelinks insertions for passing to the DB
+        * Skips the titles specified by the 2-D array $existing
+        * @param array $existing
+        * @return array
+        */
+       private function getLinkInsertions( $existing = [] ) {
+               $arr = [];
+               foreach ( $this->mLinks as $ns => $dbkeys ) {
+                       $diffs = isset( $existing[$ns] )
+                               ? array_diff_key( $dbkeys, $existing[$ns] )
+                               : $dbkeys;
+                       foreach ( $diffs as $dbk => $id ) {
+                               $arr[] = [
+                                       'pl_from' => $this->mId,
+                                       'pl_from_namespace' => $this->mTitle->getNamespace(),
+                                       'pl_namespace' => $ns,
+                                       'pl_title' => $dbk
+                               ];
+                       }
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of template insertions. Like getLinkInsertions()
+        * @param array $existing
+        * @return array
+        */
+       private function getTemplateInsertions( $existing = [] ) {
+               $arr = [];
+               foreach ( $this->mTemplates as $ns => $dbkeys ) {
+                       $diffs = isset( $existing[$ns] ) ? array_diff_key( $dbkeys, $existing[$ns] ) : $dbkeys;
+                       foreach ( $diffs as $dbk => $id ) {
+                               $arr[] = [
+                                       'tl_from' => $this->mId,
+                                       'tl_from_namespace' => $this->mTitle->getNamespace(),
+                                       'tl_namespace' => $ns,
+                                       'tl_title' => $dbk
+                               ];
+                       }
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of image insertions
+        * Skips the names specified in $existing
+        * @param array $existing
+        * @return array
+        */
+       private function getImageInsertions( $existing = [] ) {
+               $arr = [];
+               $diffs = array_diff_key( $this->mImages, $existing );
+               foreach ( $diffs as $iname => $dummy ) {
+                       $arr[] = [
+                               'il_from' => $this->mId,
+                               'il_from_namespace' => $this->mTitle->getNamespace(),
+                               'il_to' => $iname
+                       ];
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of externallinks insertions. Skips the names specified in $existing
+        * @param array $existing
+        * @return array
+        */
+       private function getExternalInsertions( $existing = [] ) {
+               $arr = [];
+               $diffs = array_diff_key( $this->mExternals, $existing );
+               foreach ( $diffs as $url => $dummy ) {
+                       foreach ( wfMakeUrlIndexes( $url ) as $index ) {
+                               $arr[] = [
+                                       'el_from' => $this->mId,
+                                       'el_to' => $url,
+                                       'el_index' => $index,
+                               ];
+                       }
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of category insertions
+        *
+        * @param array $existing Mapping existing category names to sort keys. If both
+        * match a link in $this, the link will be omitted from the output
+        *
+        * @return array
+        */
+       private function getCategoryInsertions( $existing = [] ) {
+               global $wgContLang, $wgCategoryCollation;
+               $diffs = array_diff_assoc( $this->mCategories, $existing );
+               $arr = [];
+               foreach ( $diffs as $name => $prefix ) {
+                       $nt = Title::makeTitleSafe( NS_CATEGORY, $name );
+                       $wgContLang->findVariantLink( $name, $nt, true );
+
+                       if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
+                               $type = 'subcat';
+                       } elseif ( $this->mTitle->getNamespace() == NS_FILE ) {
+                               $type = 'file';
+                       } else {
+                               $type = 'page';
+                       }
+
+                       # Treat custom sortkeys as a prefix, so that if multiple
+                       # things are forced to sort as '*' or something, they'll
+                       # sort properly in the category rather than in page_id
+                       # order or such.
+                       $sortkey = Collation::singleton()->getSortKey(
+                               $this->mTitle->getCategorySortkey( $prefix ) );
+
+                       $arr[] = [
+                               'cl_from' => $this->mId,
+                               'cl_to' => $name,
+                               'cl_sortkey' => $sortkey,
+                               'cl_timestamp' => $this->getDB()->timestamp(),
+                               'cl_sortkey_prefix' => $prefix,
+                               'cl_collation' => $wgCategoryCollation,
+                               'cl_type' => $type,
+                       ];
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of interlanguage link insertions
+        *
+        * @param array $existing Mapping existing language codes to titles
+        *
+        * @return array
+        */
+       private function getInterlangInsertions( $existing = [] ) {
+               $diffs = array_diff_assoc( $this->mInterlangs, $existing );
+               $arr = [];
+               foreach ( $diffs as $lang => $title ) {
+                       $arr[] = [
+                               'll_from' => $this->mId,
+                               'll_lang' => $lang,
+                               'll_title' => $title
+                       ];
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of page property insertions
+        * @param array $existing
+        * @return array
+        */
+       function getPropertyInsertions( $existing = [] ) {
+               $diffs = array_diff_assoc( $this->mProperties, $existing );
+
+               $arr = [];
+               foreach ( array_keys( $diffs ) as $name ) {
+                       $arr[] = $this->getPagePropRowData( $name );
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Returns an associative array to be used for inserting a row into
+        * the page_props table. Besides the given property name, this will
+        * include the page id from $this->mId and any property value from
+        * $this->mProperties.
+        *
+        * The array returned will include the pp_sortkey field if this
+        * is present in the database (as indicated by $wgPagePropsHaveSortkey).
+        * The sortkey value is currently determined by getPropertySortKeyValue().
+        *
+        * @note this assumes that $this->mProperties[$prop] is defined.
+        *
+        * @param string $prop The name of the property.
+        *
+        * @return array
+        */
+       private function getPagePropRowData( $prop ) {
+               global $wgPagePropsHaveSortkey;
+
+               $value = $this->mProperties[$prop];
+
+               $row = [
+                       'pp_page' => $this->mId,
+                       'pp_propname' => $prop,
+                       'pp_value' => $value,
+               ];
+
+               if ( $wgPagePropsHaveSortkey ) {
+                       $row['pp_sortkey'] = $this->getPropertySortKeyValue( $value );
+               }
+
+               return $row;
+       }
+
+       /**
+        * Determines the sort key for the given property value.
+        * This will return $value if it is a float or int,
+        * 1 or resp. 0 if it is a bool, and null otherwise.
+        *
+        * @note In the future, we may allow the sortkey to be specified explicitly
+        *       in ParserOutput::setProperty.
+        *
+        * @param mixed $value
+        *
+        * @return float|null
+        */
+       private function getPropertySortKeyValue( $value ) {
+               if ( is_int( $value ) || is_float( $value ) || is_bool( $value ) ) {
+                       return floatval( $value );
+               }
+
+               return null;
+       }
+
+       /**
+        * Get an array of interwiki insertions for passing to the DB
+        * Skips the titles specified by the 2-D array $existing
+        * @param array $existing
+        * @return array
+        */
+       private function getInterwikiInsertions( $existing = [] ) {
+               $arr = [];
+               foreach ( $this->mInterwikis as $prefix => $dbkeys ) {
+                       $diffs = isset( $existing[$prefix] )
+                               ? array_diff_key( $dbkeys, $existing[$prefix] )
+                               : $dbkeys;
+
+                       foreach ( $diffs as $dbk => $id ) {
+                               $arr[] = [
+                                       'iwl_from' => $this->mId,
+                                       'iwl_prefix' => $prefix,
+                                       'iwl_title' => $dbk
+                               ];
+                       }
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Given an array of existing links, returns those links which are not in $this
+        * and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getLinkDeletions( $existing ) {
+               $del = [];
+               foreach ( $existing as $ns => $dbkeys ) {
+                       if ( isset( $this->mLinks[$ns] ) ) {
+                               $del[$ns] = array_diff_key( $existing[$ns], $this->mLinks[$ns] );
+                       } else {
+                               $del[$ns] = $existing[$ns];
+                       }
+               }
+
+               return $del;
+       }
+
+       /**
+        * Given an array of existing templates, returns those templates which are not in $this
+        * and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getTemplateDeletions( $existing ) {
+               $del = [];
+               foreach ( $existing as $ns => $dbkeys ) {
+                       if ( isset( $this->mTemplates[$ns] ) ) {
+                               $del[$ns] = array_diff_key( $existing[$ns], $this->mTemplates[$ns] );
+                       } else {
+                               $del[$ns] = $existing[$ns];
+                       }
+               }
+
+               return $del;
+       }
+
+       /**
+        * Given an array of existing images, returns those images which are not in $this
+        * and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getImageDeletions( $existing ) {
+               return array_diff_key( $existing, $this->mImages );
+       }
+
+       /**
+        * Given an array of existing external links, returns those links which are not
+        * in $this and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getExternalDeletions( $existing ) {
+               return array_diff_key( $existing, $this->mExternals );
+       }
+
+       /**
+        * Given an array of existing categories, returns those categories which are not in $this
+        * and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getCategoryDeletions( $existing ) {
+               return array_diff_assoc( $existing, $this->mCategories );
+       }
+
+       /**
+        * Given an array of existing interlanguage links, returns those links which are not
+        * in $this and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getInterlangDeletions( $existing ) {
+               return array_diff_assoc( $existing, $this->mInterlangs );
+       }
+
+       /**
+        * Get array of properties which should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       function getPropertyDeletions( $existing ) {
+               return array_diff_assoc( $existing, $this->mProperties );
+       }
+
+       /**
+        * Given an array of existing interwiki links, returns those links which are not in $this
+        * and thus should be deleted.
+        * @param array $existing
+        * @return array
+        */
+       private function getInterwikiDeletions( $existing ) {
+               $del = [];
+               foreach ( $existing as $prefix => $dbkeys ) {
+                       if ( isset( $this->mInterwikis[$prefix] ) ) {
+                               $del[$prefix] = array_diff_key( $existing[$prefix], $this->mInterwikis[$prefix] );
+                       } else {
+                               $del[$prefix] = $existing[$prefix];
+                       }
+               }
+
+               return $del;
+       }
+
+       /**
+        * Get an array of existing links, as a 2-D array
+        *
+        * @return array
+        */
+       private function getExistingLinks() {
+               $res = $this->getDB()->select( 'pagelinks', [ 'pl_namespace', 'pl_title' ],
+                       [ 'pl_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       if ( !isset( $arr[$row->pl_namespace] ) ) {
+                               $arr[$row->pl_namespace] = [];
+                       }
+                       $arr[$row->pl_namespace][$row->pl_title] = 1;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing templates, as a 2-D array
+        *
+        * @return array
+        */
+       private function getExistingTemplates() {
+               $res = $this->getDB()->select( 'templatelinks', [ 'tl_namespace', 'tl_title' ],
+                       [ 'tl_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       if ( !isset( $arr[$row->tl_namespace] ) ) {
+                               $arr[$row->tl_namespace] = [];
+                       }
+                       $arr[$row->tl_namespace][$row->tl_title] = 1;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing images, image names in the keys
+        *
+        * @return array
+        */
+       private function getExistingImages() {
+               $res = $this->getDB()->select( 'imagelinks', [ 'il_to' ],
+                       [ 'il_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       $arr[$row->il_to] = 1;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing external links, URLs in the keys
+        *
+        * @return array
+        */
+       private function getExistingExternals() {
+               $res = $this->getDB()->select( 'externallinks', [ 'el_to' ],
+                       [ 'el_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       $arr[$row->el_to] = 1;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing categories, with the name in the key and sort key in the value.
+        *
+        * @return array
+        */
+       private function getExistingCategories() {
+               $res = $this->getDB()->select( 'categorylinks', [ 'cl_to', 'cl_sortkey_prefix' ],
+                       [ 'cl_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       $arr[$row->cl_to] = $row->cl_sortkey_prefix;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing interlanguage links, with the language code in the key and the
+        * title in the value.
+        *
+        * @return array
+        */
+       private function getExistingInterlangs() {
+               $res = $this->getDB()->select( 'langlinks', [ 'll_lang', 'll_title' ],
+                       [ 'll_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       $arr[$row->ll_lang] = $row->ll_title;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing inline interwiki links, as a 2-D array
+        * @return array (prefix => array(dbkey => 1))
+        */
+       private function getExistingInterwikis() {
+               $res = $this->getDB()->select( 'iwlinks', [ 'iwl_prefix', 'iwl_title' ],
+                       [ 'iwl_from' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       if ( !isset( $arr[$row->iwl_prefix] ) ) {
+                               $arr[$row->iwl_prefix] = [];
+                       }
+                       $arr[$row->iwl_prefix][$row->iwl_title] = 1;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Get an array of existing categories, with the name in the key and sort key in the value.
+        *
+        * @return array Array of property names and values
+        */
+       private function getExistingProperties() {
+               $res = $this->getDB()->select( 'page_props', [ 'pp_propname', 'pp_value' ],
+                       [ 'pp_page' => $this->mId ], __METHOD__ );
+               $arr = [];
+               foreach ( $res as $row ) {
+                       $arr[$row->pp_propname] = $row->pp_value;
+               }
+
+               return $arr;
+       }
+
+       /**
+        * Return the title object of the page being updated
+        * @return Title
+        */
+       public function getTitle() {
+               return $this->mTitle;
+       }
+
+       /**
+        * Returns parser output
+        * @since 1.19
+        * @return ParserOutput
+        */
+       public function getParserOutput() {
+               return $this->mParserOutput;
+       }
+
+       /**
+        * Return the list of images used as generated by the parser
+        * @return array
+        */
+       public function getImages() {
+               return $this->mImages;
+       }
+
+       /**
+        * Set the revision corresponding to this LinksUpdate
+        *
+        * @since 1.27
+        *
+        * @param Revision $revision
+        */
+       public function setRevision( Revision $revision ) {
+               $this->mRevision = $revision;
+       }
+
+       /**
+        * @since 1.28
+        * @return null|Revision
+        */
+       public function getRevision() {
+               return $this->mRevision;
+       }
+
+       /**
+        * Set the User who triggered this LinksUpdate
+        *
+        * @since 1.27
+        * @param User $user
+        */
+       public function setTriggeringUser( User $user ) {
+               $this->user = $user;
+       }
+
+       /**
+        * @since 1.27
+        * @return null|User
+        */
+       public function getTriggeringUser() {
+               return $this->user;
+       }
+
+       /**
+        * Invalidate any necessary link lists related to page property changes
+        * @param array $changed
+        */
+       private function invalidateProperties( $changed ) {
+               global $wgPagePropLinkInvalidations;
+
+               foreach ( $changed as $name => $value ) {
+                       if ( isset( $wgPagePropLinkInvalidations[$name] ) ) {
+                               $inv = $wgPagePropLinkInvalidations[$name];
+                               if ( !is_array( $inv ) ) {
+                                       $inv = [ $inv ];
+                               }
+                               foreach ( $inv as $table ) {
+                                       DeferredUpdates::addUpdate( new HTMLCacheUpdate( $this->mTitle, $table ) );
+                               }
+                       }
+               }
+       }
+
+       /**
+        * Fetch page links added by this LinksUpdate.  Only available after the update is complete.
+        * @since 1.22
+        * @return null|array Array of Titles
+        */
+       public function getAddedLinks() {
+               if ( $this->linkInsertions === null ) {
+                       return null;
+               }
+               $result = [];
+               foreach ( $this->linkInsertions as $insertion ) {
+                       $result[] = Title::makeTitle( $insertion['pl_namespace'], $insertion['pl_title'] );
+               }
+
+               return $result;
+       }
+
+       /**
+        * Fetch page links removed by this LinksUpdate.  Only available after the update is complete.
+        * @since 1.22
+        * @return null|array Array of Titles
+        */
+       public function getRemovedLinks() {
+               if ( $this->linkDeletions === null ) {
+                       return null;
+               }
+               $result = [];
+               foreach ( $this->linkDeletions as $ns => $titles ) {
+                       foreach ( $titles as $title => $unused ) {
+                               $result[] = Title::makeTitle( $ns, $title );
+                       }
+               }
+
+               return $result;
+       }
+
+       /**
+        * Fetch page properties added by this LinksUpdate.
+        * Only available after the update is complete.
+        * @since 1.28
+        * @return null|array
+        */
+       public function getAddedProperties() {
+               return $this->propertyInsertions;
+       }
+
+       /**
+        * Fetch page properties removed by this LinksUpdate.
+        * Only available after the update is complete.
+        * @since 1.28
+        * @return null|array
+        */
+       public function getRemovedProperties() {
+               return $this->propertyDeletions;
+       }
+
+       /**
+        * Update links table freshness
+        */
+       private function updateLinksTimestamp() {
+               if ( $this->mId ) {
+                       // The link updates made here only reflect the freshness of the parser output
+                       $timestamp = $this->mParserOutput->getCacheTime();
+                       $this->getDB()->update( 'page',
+                               [ 'page_links_updated' => $this->getDB()->timestamp( $timestamp ) ],
+                               [ 'page_id' => $this->mId ],
+                               __METHOD__
+                       );
+               }
+       }
+
+       /**
+        * @return IDatabase
+        */
+       private function getDB() {
+               if ( !$this->db ) {
+                       $this->db = wfGetDB( DB_MASTER );
+               }
+
+               return $this->db;
+       }
+
+       public function getAsJobSpecification() {
+               if ( $this->user ) {
+                       $userInfo = [
+                               'userId' => $this->user->getId(),
+                               'userName' => $this->user->getName(),
+                       ];
+               } else {
+                       $userInfo = false;
+               }
+
+               if ( $this->mRevision ) {
+                       $triggeringRevisionId = $this->mRevision->getId();
+               } else {
+                       $triggeringRevisionId = false;
+               }
+
+               return [
+                       'wiki' => WikiMap::getWikiIdFromDomain( $this->getDB()->getDomainID() ),
+                       'job'  => new JobSpecification(
+                               'refreshLinksPrioritized',
+                               [
+                                       // Reuse the parser cache if it was saved
+                                       'rootJobTimestamp' => $this->mParserOutput->getCacheTime(),
+                                       'useRecursiveLinksUpdate' => $this->mRecursive,
+                                       'triggeringUser' => $userInfo,
+                                       'triggeringRevisionId' => $triggeringRevisionId,
+                               ],
+                               [ 'removeDuplicates' => true ],
+                               $this->getTitle()
+                       )
+               ];
+       }
+}