Apply $wgMaxArticleSize more exactly

[mediawiki.git] / includes / deferred / LinksDeletionUpdate.php

<?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
 */
/**
 * Update object handling the cleanup of links tables after a page was deleted.
 **/
class LinksDeletionUpdate extends SqlDataUpdate implements EnqueueableDataUpdate {
        /** @var WikiPage */
        protected $page;
        /** @var integer */
        protected $pageId;
        /** @var string */
        protected $timestamp;

        /**
         * @param WikiPage $page Page we are updating
         * @param integer|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( false ); // no implicit transaction

                $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() {
                $config = RequestContext::getMain()->getConfig();
                $batchSize = $config->get( 'UpdateRowsPerQuery' );

                // Page may already be deleted, so don't just getId()
                $id = $this->pageId;
                // 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->mDb, $id );

                // Delete restrictions for it
                $this->mDb->delete( 'page_restrictions', [ 'pr_page' => $id ], __METHOD__ );

                // Fix category table counts
                $cats = $this->mDb->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 ) {
                                $this->mDb->commit( __METHOD__, 'flush' );
                                wfGetLBFactory()->waitForReplication( [ 'wiki' => $this->mDb->getWikiID() ] );
                        }
                }

                // If using cascading deletes, we can skip some explicit deletes
                if ( !$this->mDb->cascadingDeletes() ) {
                        // Delete outgoing links
                        $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
                        $this->mDb->delete( 'redirect', [ 'rd_from' => $id ], __METHOD__ );
                        $this->mDb->delete( 'page_props', [ 'pp_page' => $id ], __METHOD__ );
                }

                // If using cleanup triggers, we can skip some manual deletes
                if ( !$this->mDb->cleanupTriggers() ) {
                        $title = $this->page->getTitle();
                        // Find recentchanges entries to clean up...
                        $rcIdsForTitle = $this->mDb->selectFieldValues(
                                'recentchanges',
                                'rc_id',
                                [
                                        'rc_type != ' . RC_LOG,
                                        'rc_namespace' => $title->getNamespace(),
                                        'rc_title' => $title->getDBkey(),
                                        'rc_timestamp < ' .
                                                $this->mDb->addQuotes( $this->mDb->timestamp( $this->timestamp ) )
                                ],
                                __METHOD__
                        );
                        $rcIdsForPage = $this->mDb->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 ) {
                                $this->mDb->delete( 'recentchanges', [ 'rc_id' => $rcIdBatch ], __METHOD__ );
                                if ( count( $rcIdBatches ) > 1 ) {
                                        $this->mDb->commit( __METHOD__, 'flush' );
                                        wfGetLBFactory()->waitForReplication( [ 'wiki' => $this->mDb->getWikiID() ] );
                                }
                        }
                }

                $this->mDb->onTransactionIdle( function() use ( &$scopedLock ) {
                        // Release the lock *after* the final COMMIT for correctness
                        ScopedCallback::consume( $scopedLock );
                } );
        }

        private function batchDeleteByPK( $table, array $conds, array $pk, $bSize ) {
                $dbw = $this->mDb; // convenience
                $res = $dbw->select( $table, $pk, $conds, __METHOD__ );

                $pkDeleteConds = [];
                foreach ( $res as $row ) {
                        $pkDeleteConds[] = $this->mDb->makeList( (array)$row, LIST_AND );
                        if ( count( $pkDeleteConds ) >= $bSize ) {
                                $dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
                                $dbw->commit( __METHOD__, 'flush' );
                                wfGetLBFactory()->waitForReplication( [ 'wiki' => $dbw->getWikiID() ] );
                                $pkDeleteConds = [];
                        }
                }

                if ( $pkDeleteConds ) {
                        $dbw->delete( $table, $dbw->makeList( $pkDeleteConds, LIST_OR ), __METHOD__ );
                }
        }

        public function getAsJobSpecification() {
                return [
                        'wiki' => $this->mDb->getWikiID(),
                        'job'  => new JobSpecification(
                                'deleteLinks',
                                [ 'pageId' => $this->pageId, 'timestamp' => $this->timestamp ],
                                [ 'removeDuplicates' => true ],
                                $this->page->getTitle()
                        )
                ];
        }
}