wikimedia/mediawiki-extensions-CirrusSearch

<?php

namespace CirrusSearch;

use ManualLogEntry;
use MediaWiki\Hook\PageMoveCompleteHook;
use MediaWiki\Linker\LinkTarget;
use MediaWiki\Page\Hook\PageDeleteCompleteHook;
use MediaWiki\Page\Hook\PageDeleteHook;
use MediaWiki\Page\ProperPageIdentity;
use MediaWiki\Permissions\Authority;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Storage\EditResult;
use MediaWiki\Storage\Hook\PageSaveCompleteHook;
use MediaWiki\User\UserIdentity;
use StatusValue;

/**
 * Listen to a set of hooks to keep track if a pageId was involved in a "page change".
 * A page change is a change happening to the page itself, based on the hooks used by EventBus
 * to emit its page_change stream we use this to determine in which stream we might emit a cirrus
 * event based on a LinksUpdateComplete hook. Mainly we want to identify if a particular LinksUpdate
 * is caused by a page change or something else unrelated to the life of the page.
 */
class PageChangeTracker implements
    PageSaveCompleteHook,
    PageMoveCompleteHook,
    PageDeleteCompleteHook,
    PageDeleteHook
{
    /**
     * @var array<int,bool>
     */
    private array $changedPages = [];
    private int $maxStateSize;

    public function __construct( int $maxStateSize = 512 ) {
        $this->maxStateSize = $maxStateSize;
    }

    private function flag( int $pageId ): void {
        if ( count( $this->changedPages ) >= $this->maxStateSize ) {
            $this->changedPages = array_slice( $this->changedPages, 1 - $this->maxStateSize, null, true );
        }
        $this->changedPages[$pageId] = true;
    }

    /**
     * @param ProperPageIdentity $page
     * @param Authority $deleter
     * @param string $reason
     * @param int $pageID
     * @param RevisionRecord $deletedRev
     * @param ManualLogEntry $logEntry
     * @param int $archivedRevisionCount
     * @return void
     */
    public function onPageDeleteComplete(
        ProperPageIdentity $page,
        Authority $deleter,
        string $reason,
        int $pageID,
        RevisionRecord $deletedRev,
        ManualLogEntry $logEntry,
        int $archivedRevisionCount
    ) {
        $this->flag( $pageID );
    }

    /**
     * @param ProperPageIdentity $page
     * @param Authority $deleter
     * @param string $reason
     * @param StatusValue $status
     * @param bool $suppress
     * @return void
     */
    public function onPageDelete( ProperPageIdentity $page,
        Authority $deleter,
        string $reason,
        StatusValue $status,
        bool $suppress
    ) {
        $this->flag( $page->getId() );
    }

    /**
     * @param LinkTarget $old Old title
     * @param LinkTarget $new New title
     * @param UserIdentity $user User who did the move
     * @param int $pageid Database ID of the page that's been moved
     * @param int $redirid Database ID of the created redirect
     * @param string $reason Reason for the move
     * @param RevisionRecord $revision RevisionRecord created by the move
     * @return bool|void True or no return value to continue or false stop other hook handlers,
     *     doesn't abort the move itself
     */
    public function onPageMoveComplete( $old, $new, $user, $pageid, $redirid, $reason, $revision ) {
        $this->flag( $pageid );
        $this->flag( $redirid );
    }

    /**
     * @param \WikiPage $wikiPage WikiPage modified
     * @param UserIdentity $user User performing the modification
     * @param string $summary Edit summary/comment
     * @param int $flags Flags passed to WikiPage::doUserEditContent()
     * @param RevisionRecord $revisionRecord New RevisionRecord of the article
     * @param EditResult $editResult Object storing information about the effects of this edit,
     *   including which edits were reverted and which edit is this based on (for reverts and null
     *   edits).
     * @return bool|void True or no return value to continue or false to stop other hook handlers
     *    from being called; save cannot be aborted
     */
    public function onPageSaveComplete( $wikiPage, $user, $summary, $flags, $revisionRecord, $editResult ) {
        if ( !$editResult->isNullEdit() ) {
            $this->flag( $wikiPage->getId() );
        }
    }

    /**
     * Test if this pageId was references in a hook call earlier.
     * Calling this function resets the state held by this class.
     * @param int $pageId
     * @return bool
     */
    public function isPageChange( int $pageId ): bool {
        if ( array_key_exists( $pageId, $this->changedPages ) ) {
            unset( $this->changedPages[$pageId] );
            return true;
        }
        return false;
    }
}