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includes/deferred/LinksDeletionUpdate.php (1 issue)

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<?php
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/**
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 * Updater for link tracking tables after a page edit.
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License along
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 * with this program; if not, write to the Free Software Foundation, Inc.,
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 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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 * http://www.gnu.org/copyleft/gpl.html
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 *
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 * @file
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 */
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use MediaWiki\MediaWikiServices;
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use Wikimedia\ScopedCallback;
0 ignored issues
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This use statement conflicts with another class in this namespace, ScopedCallback.

Let’s assume that you have a directory layout like this:

.
|-- OtherDir
|   |-- Bar.php
|   `-- Foo.php
`-- SomeDir
    `-- Foo.php

and let’s assume the following content of Bar.php:

// Bar.php
namespace OtherDir;

use SomeDir\Foo; // This now conflicts the class OtherDir\Foo

If both files OtherDir/Foo.php and SomeDir/Foo.php are loaded in the same runtime, you will see a PHP error such as the following:

PHP Fatal error:  Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.php

However, as OtherDir/Foo.php does not necessarily have to be loaded and the error is only triggered if it is loaded before OtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias:

// Bar.php
namespace OtherDir;

use SomeDir\Foo as SomeDirFoo; // There is no conflict anymore.
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/**
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 * Update object handling the cleanup of links tables after a page was deleted.
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 **/
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class LinksDeletionUpdate extends DataUpdate implements EnqueueableDataUpdate {
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	/** @var WikiPage */
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	protected $page;
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	/** @var integer */
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	protected $pageId;
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	/** @var string */
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	protected $timestamp;
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	/** @var IDatabase */
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	private $db;
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	/**
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	 * @param WikiPage $page Page we are updating
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	 * @param integer|null $pageId ID of the page we are updating [optional]
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	 * @param string|null $timestamp TS_MW timestamp of deletion
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	 * @throws MWException
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	 */
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	function __construct( WikiPage $page, $pageId = null, $timestamp = null ) {
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		parent::__construct();
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		$this->page = $page;
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		if ( $pageId ) {
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			$this->pageId = $pageId; // page ID at time of deletion
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		} elseif ( $page->exists() ) {
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			$this->pageId = $page->getId();
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		} else {
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			throw new InvalidArgumentException( "Page ID not known. Page doesn't exist?" );
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		}
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		$this->timestamp = $timestamp ?: wfTimestampNow();
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	}
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	public function doUpdate() {
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		$services = MediaWikiServices::getInstance();
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		$config = $services->getMainConfig();
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		$lbFactory = $services->getDBLoadBalancerFactory();
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		$batchSize = $config->get( 'UpdateRowsPerQuery' );
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		// Page may already be deleted, so don't just getId()
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		$id = $this->pageId;
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		if ( $this->ticket ) {
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			// Make sure all links update threads see the changes of each other.
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			// This handles the case when updates have to batched into several COMMITs.
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			$scopedLock = LinksUpdate::acquirePageLock( $this->getDB(), $id );
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		}
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		$title = $this->page->getTitle();
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		$dbw = $this->getDB(); // convenience
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		// Delete restrictions for it
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		$dbw->delete( 'page_restrictions', [ 'pr_page' => $id ], __METHOD__ );
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		// Fix category table counts
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		$cats = $dbw->selectFieldValues(
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			'categorylinks',
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			'cl_to',
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			[ 'cl_from' => $id ],
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			__METHOD__
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		);
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		$catBatches = array_chunk( $cats, $batchSize );
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		foreach ( $catBatches as $catBatch ) {
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			$this->page->updateCategoryCounts( [], $catBatch, $id );
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			if ( count( $catBatches ) > 1 ) {
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				$lbFactory->commitAndWaitForReplication(
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					__METHOD__, $this->ticket, [ 'wiki' => $dbw->getWikiID() ]
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				);
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			}
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		}
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		// Refresh the category table entry if it seems to have no pages. Check
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		// master for the most up-to-date cat_pages count.
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		if ( $title->getNamespace() === NS_CATEGORY ) {
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			$row = $dbw->selectRow(
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				'category',
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				[ 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ],
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				[ 'cat_title' => $title->getDBkey(), 'cat_pages <= 0' ],
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				__METHOD__
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			);
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			if ( $row ) {
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				Category::newFromRow( $row, $title )->refreshCounts();
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			}
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		}
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		$this->batchDeleteByPK(
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			'pagelinks',
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			[ 'pl_from' => $id ],
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			[ 'pl_from', 'pl_namespace', 'pl_title' ],
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			$batchSize
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		);
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		$this->batchDeleteByPK(
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			'imagelinks',
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			[ 'il_from' => $id ],
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			[ 'il_from', 'il_to' ],
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			$batchSize
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		);
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		$this->batchDeleteByPK(
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			'categorylinks',
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			[ 'cl_from' => $id ],
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			[ 'cl_from', 'cl_to' ],
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			$batchSize
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		);
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		$this->batchDeleteByPK(
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			'templatelinks',
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			[ 'tl_from' => $id ],
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			[ 'tl_from', 'tl_namespace', 'tl_title' ],
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			$batchSize
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		);
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		$this->batchDeleteByPK(
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			'externallinks',
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			[ 'el_from' => $id ],
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			[ 'el_id' ],
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			$batchSize
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		);
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		$this->batchDeleteByPK(
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			'langlinks',
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			[ 'll_from' => $id ],
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			[ 'll_from', 'll_lang' ],
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			$batchSize
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		);
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		$this->batchDeleteByPK(
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			'iwlinks',
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			[ 'iwl_from' => $id ],
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			[ 'iwl_from', 'iwl_prefix', 'iwl_title' ],
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			$batchSize
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		);
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		// Delete any redirect entry or page props entries
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		$dbw->delete( 'redirect', [ 'rd_from' => $id ], __METHOD__ );
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		$dbw->delete( 'page_props', [ 'pp_page' => $id ], __METHOD__ );
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		// Find recentchanges entries to clean up...
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		$rcIdsForTitle = $dbw->selectFieldValues(
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			'recentchanges',
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			'rc_id',
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			[
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				'rc_type != ' . RC_LOG,
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				'rc_namespace' => $title->getNamespace(),
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				'rc_title' => $title->getDBkey(),
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				'rc_timestamp < ' .
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					$dbw->addQuotes( $dbw->timestamp( $this->timestamp ) )
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			],
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			__METHOD__
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		);
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		$rcIdsForPage = $dbw->selectFieldValues(
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			'recentchanges',
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			'rc_id',
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			[ 'rc_type != ' . RC_LOG, 'rc_cur_id' => $id ],
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			__METHOD__
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		);
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		// T98706: delete by PK to avoid lock contention with RC delete log insertions
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		$rcIdBatches = array_chunk( array_merge( $rcIdsForTitle, $rcIdsForPage ), $batchSize );
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		foreach ( $rcIdBatches as $rcIdBatch ) {
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			$dbw->delete( 'recentchanges', [ 'rc_id' => $rcIdBatch ], __METHOD__ );
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			if ( count( $rcIdBatches ) > 1 ) {
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				$lbFactory->commitAndWaitForReplication(
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					__METHOD__, $this->ticket, [ 'wiki' => $dbw->getWikiID() ]
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				);
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			}
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		}
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		// Commit and release the lock (if set)
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		ScopedCallback::consume( $scopedLock );
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	}
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	private function batchDeleteByPK( $table, array $conds, array $pk, $bSize ) {
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		$services = MediaWikiServices::getInstance();
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		$lbFactory = $services->getDBLoadBalancerFactory();
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		$dbw = $this->getDB(); // convenience
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		$res = $dbw->select( $table, $pk, $conds, __METHOD__ );
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		$pkDeleteConds = [];
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		foreach ( $res as $row ) {
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			$pkDeleteConds[] = $dbw->makeList( (array)$row, LIST_AND );
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			if ( count( $pkDeleteConds ) >= $bSize ) {
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				$dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
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				$lbFactory->commitAndWaitForReplication(
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					__METHOD__, $this->ticket, [ 'wiki' => $dbw->getWikiID() ]
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				);
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				$pkDeleteConds = [];
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			}
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		}
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		if ( $pkDeleteConds ) {
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			$dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
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		}
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	}
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	protected function getDB() {
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		if ( !$this->db ) {
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			$this->db = wfGetDB( DB_MASTER );
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		}
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		return $this->db;
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	}
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	public function getAsJobSpecification() {
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		return [
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			'wiki' => $this->getDB()->getWikiID(),
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			'job'  => new JobSpecification(
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				'deleteLinks',
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				[ 'pageId' => $this->pageId, 'timestamp' => $this->timestamp ],
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				[ 'removeDuplicates' => true ],
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				$this->page->getTitle()
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			)
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		];
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	}
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}
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