1 files changed, 242 insertions, 0 deletions
diff --git a/www/wiki/includes/deferred/LinksDeletionUpdate.php b/www/wiki/includes/deferred/LinksDeletionUpdate.php
new file mode 100644
index 00000000..52e996a0
--- /dev/null
+++ b/www/wiki/includes/deferred/LinksDeletionUpdate.php
@@ -0,0 +1,242 @@
+<?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 MediaWiki\MediaWikiServices;
+use Wikimedia\ScopedCallback;
+use Wikimedia\Rdbms\IDatabase;
+
+/**
+ * Update object handling the cleanup of links tables after a page was deleted.
+ */
+class LinksDeletionUpdate extends DataUpdate implements EnqueueableDataUpdate {
+	/** @var WikiPage */
+	protected $page;
+	/** @var int */
+	protected $pageId;
+	/** @var string */
+	protected $timestamp;
+
+	/** @var IDatabase */
+	private $db;
+
+	/**
+	 * @param WikiPage $page Page we are updating
+	 * @param int|null $pageId ID of the page we are updating [optional]
+	 * @param string|null $timestamp TS_MW timestamp of deletion
+	 * @throws MWException
+	 */
+	function __construct( WikiPage $page, $pageId = null, $timestamp = null ) {
+		parent::__construct();
+
+		$this->page = $page;
+		if ( $pageId ) {
+			$this->pageId = $pageId; // page ID at time of deletion
+		} elseif ( $page->exists() ) {
+			$this->pageId = $page->getId();
+		} else {
+			throw new InvalidArgumentException( "Page ID not known. Page doesn't exist?" );
+		}
+
+		$this->timestamp = $timestamp ?: wfTimestampNow();
+	}
+
+	public function doUpdate() {
+		$services = MediaWikiServices::getInstance();
+		$config = $services->getMainConfig();
+		$lbFactory = $services->getDBLoadBalancerFactory();
+		$batchSize = $config->get( 'UpdateRowsPerQuery' );
+
+		// Page may already be deleted, so don't just getId()
+		$id = $this->pageId;
+
+		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 = LinksUpdate::acquirePageLock( $this->getDB(), $id );
+		}
+
+		$title = $this->page->getTitle();
+		$dbw = $this->getDB(); // convenience
+
+		// Delete restrictions for it
+		$dbw->delete( 'page_restrictions', [ 'pr_page' => $id ], __METHOD__ );
+
+		// Fix category table counts
+		$cats = $dbw->selectFieldValues(
+			'categorylinks',
+			'cl_to',
+			[ 'cl_from' => $id ],
+			__METHOD__
+		);
+		$catBatches = array_chunk( $cats, $batchSize );
+		foreach ( $catBatches as $catBatch ) {
+			$this->page->updateCategoryCounts( [], $catBatch, $id );
+			if ( count( $catBatches ) > 1 ) {
+				$lbFactory->commitAndWaitForReplication(
+					__METHOD__, $this->ticket, [ 'domain' => $dbw->getDomainID() ]
+				);
+			}
+		}
+
+		// Refresh the category table entry if it seems to have no pages. Check
+		// master for the most up-to-date cat_pages count.
+		if ( $title->getNamespace() === NS_CATEGORY ) {
+			$row = $dbw->selectRow(
+				'category',
+				[ 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ],
+				[ 'cat_title' => $title->getDBkey(), 'cat_pages <= 0' ],
+				__METHOD__
+			);
+			if ( $row ) {
+				$cat = Category::newFromRow( $row, $title );
+				// T166757: do the update after the main job DB commit
+				DeferredUpdates::addCallableUpdate( function () use ( $cat ) {
+					$cat->refreshCounts();
+				} );
+			}
+		}
+
+		$this->batchDeleteByPK(
+			'pagelinks',
+			[ 'pl_from' => $id ],
+			[ 'pl_from', 'pl_namespace', 'pl_title' ],
+			$batchSize
+		);
+		$this->batchDeleteByPK(
+			'imagelinks',
+			[ 'il_from' => $id ],
+			[ 'il_from', 'il_to' ],
+			$batchSize
+		);
+		$this->batchDeleteByPK(
+			'categorylinks',
+			[ 'cl_from' => $id ],
+			[ 'cl_from', 'cl_to' ],
+			$batchSize
+		);
+		$this->batchDeleteByPK(
+			'templatelinks',
+			[ 'tl_from' => $id ],
+			[ 'tl_from', 'tl_namespace', 'tl_title' ],
+			$batchSize
+		);
+		$this->batchDeleteByPK(
+			'externallinks',
+			[ 'el_from' => $id ],
+			[ 'el_id' ],
+			$batchSize
+		);
+		$this->batchDeleteByPK(
+			'langlinks',
+			[ 'll_from' => $id ],
+			[ 'll_from', 'll_lang' ],
+			$batchSize
+		);
+		$this->batchDeleteByPK(
+			'iwlinks',
+			[ 'iwl_from' => $id ],
+			[ 'iwl_from', 'iwl_prefix', 'iwl_title' ],
+			$batchSize
+		);
+
+		// Delete any redirect entry or page props entries
+		$dbw->delete( 'redirect', [ 'rd_from' => $id ], __METHOD__ );
+		$dbw->delete( 'page_props', [ 'pp_page' => $id ], __METHOD__ );
+
+		// Find recentchanges entries to clean up...
+		$rcIdsForTitle = $dbw->selectFieldValues(
+			'recentchanges',
+			'rc_id',
+			[
+				'rc_type != ' . RC_LOG,
+				'rc_namespace' => $title->getNamespace(),
+				'rc_title' => $title->getDBkey(),
+				'rc_timestamp < ' .
+					$dbw->addQuotes( $dbw->timestamp( $this->timestamp ) )
+			],
+			__METHOD__
+		);
+		$rcIdsForPage = $dbw->selectFieldValues(
+			'recentchanges',
+			'rc_id',
+			[ 'rc_type != ' . RC_LOG, 'rc_cur_id' => $id ],
+			__METHOD__
+		);
+
+		// T98706: delete by PK to avoid lock contention with RC delete log insertions
+		$rcIdBatches = array_chunk( array_merge( $rcIdsForTitle, $rcIdsForPage ), $batchSize );
+		foreach ( $rcIdBatches as $rcIdBatch ) {
+			$dbw->delete( 'recentchanges', [ 'rc_id' => $rcIdBatch ], __METHOD__ );
+			if ( count( $rcIdBatches ) > 1 ) {
+				$lbFactory->commitAndWaitForReplication(
+					__METHOD__, $this->ticket, [ 'domain' => $dbw->getDomainID() ]
+				);
+			}
+		}
+
+		// Commit and release the lock (if set)
+		ScopedCallback::consume( $scopedLock );
+	}
+
+	private function batchDeleteByPK( $table, array $conds, array $pk, $bSize ) {
+		$services = MediaWikiServices::getInstance();
+		$lbFactory = $services->getDBLoadBalancerFactory();
+		$dbw = $this->getDB(); // convenience
+
+		$res = $dbw->select( $table, $pk, $conds, __METHOD__ );
+
+		$pkDeleteConds = [];
+		foreach ( $res as $row ) {
+			$pkDeleteConds[] = $dbw->makeList( (array)$row, LIST_AND );
+			if ( count( $pkDeleteConds ) >= $bSize ) {
+				$dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
+				$lbFactory->commitAndWaitForReplication(
+					__METHOD__, $this->ticket, [ 'domain' => $dbw->getDomainID() ]
+				);
+				$pkDeleteConds = [];
+			}
+		}
+
+		if ( $pkDeleteConds ) {
+			$dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
+		}
+	}
+
+	protected function getDB() {
+		if ( !$this->db ) {
+			$this->db = wfGetDB( DB_MASTER );
+		}
+
+		return $this->db;
+	}
+
+	public function getAsJobSpecification() {
+		return [
+			'wiki' => WikiMap::getWikiIdFromDomain( $this->getDB()->getDomainID() ),
+			'job'  => new JobSpecification(
+				'deleteLinks',
+				[ 'pageId' => $this->pageId, 'timestamp' => $this->timestamp ],
+				[ 'removeDuplicates' => true ],
+				$this->page->getTitle()
+			)
+		];
+	}
+}