McrUndoAction.php

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<?php
use MediaWiki\MediaWikiServices;
use MediaWiki\Revision\MutableRevisionRecord;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\SlotRecord;
 
class McrUndoAction extends FormAction {
 
    protected $undo = 0, $undoafter = 0, $cur = 0;
 
    protected $curRev = null;
 
    public function getName() {
        return 'mcrundo';
    }
 
    public function getDescription() {
        return '';
    }
 
    public function show() {
        // Send a cookie so anons get talk message notifications
        // (copied from SubmitAction)
        MediaWiki\Session\SessionManager::getGlobalSession()->persist();
 
        // Some stuff copied from EditAction
        $this->useTransactionalTimeLimit();
 
        $out = $this->getOutput();
        $out->setRobotPolicy( 'noindex,nofollow' );
        if ( $this->getContext()->getConfig()->get( 'UseMediaWikiUIEverywhere' ) ) {
            $out->addModuleStyles( [
                'mediawiki.ui.input',
                'mediawiki.ui.checkbox',
            ] );
        }
 
        // IP warning headers copied from EditPage
        // (should more be copied?)
        if ( wfReadOnly() ) {
            $out->wrapWikiMsg(
                "<div id=\"mw-read-only-warning\">\n$1\n</div>",
                [ 'readonlywarning', wfReadOnlyReason() ]
            );
        } elseif ( $this->context->getUser()->isAnon() ) {
            if ( !$this->getRequest()->getCheck( 'wpPreview' ) ) {
                $out->wrapWikiMsg(
                    "<div id='mw-anon-edit-warning' class='warningbox'>\n$1\n</div>",
                    [ 'anoneditwarning',
                        // Log-in link
                        SpecialPage::getTitleFor( 'Userlogin' )->getFullURL( [
                            'returnto' => $this->getTitle()->getPrefixedDBkey()
                        ] ),
                        // Sign-up link
                        SpecialPage::getTitleFor( 'CreateAccount' )->getFullURL( [
                            'returnto' => $this->getTitle()->getPrefixedDBkey()
                        ] )
                    ]
                );
            } else {
                $out->wrapWikiMsg( "<div id=\"mw-anon-preview-warning\" class=\"warningbox\">\n$1</div>",
                    'anonpreviewwarning'
                );
            }
        }
 
        parent::show();
    }
 
    protected function initFromParameters() {
        $this->undoafter = $this->getRequest()->getInt( 'undoafter' );
        $this->undo = $this->getRequest()->getInt( 'undo' );
 
        if ( $this->undo == 0 || $this->undoafter == 0 ) {
            throw new ErrorPageError( 'mcrundofailed', 'mcrundo-missingparam' );
        }
 
        $curRev = $this->page->getRevision();
        if ( !$curRev ) {
            throw new ErrorPageError( 'mcrundofailed', 'nopagetext' );
        }
        $this->curRev = $curRev->getRevisionRecord();
        $this->cur = $this->getRequest()->getInt( 'cur', $this->curRev->getId() );
    }
 
    protected function checkCanExecute( User $user ) {
        parent::checkCanExecute( $user );
 
        $this->initFromParameters();
 
        $revisionLookup = MediaWikiServices::getInstance()->getRevisionLookup();
 
        $undoRev = $revisionLookup->getRevisionById( $this->undo );
        $oldRev = $revisionLookup->getRevisionById( $this->undoafter );
 
        if ( $undoRev === null || $oldRev === null ||
            $undoRev->isDeleted( RevisionRecord::DELETED_TEXT ) ||
            $oldRev->isDeleted( RevisionRecord::DELETED_TEXT )
        ) {
            throw new ErrorPageError( 'mcrundofailed', 'undo-norev' );
        }
 
        return true;
    }
 
    private function getNewRevision() {
        $revisionLookup = MediaWikiServices::getInstance()->getRevisionLookup();
 
        $undoRev = $revisionLookup->getRevisionById( $this->undo );
        $oldRev = $revisionLookup->getRevisionById( $this->undoafter );
        $curRev = $this->curRev;
 
        $isLatest = $curRev->getId() === $undoRev->getId();
 
        if ( $undoRev === null || $oldRev === null ||
            $undoRev->isDeleted( RevisionRecord::DELETED_TEXT ) ||
            $oldRev->isDeleted( RevisionRecord::DELETED_TEXT )
        ) {
            throw new ErrorPageError( 'mcrundofailed', 'undo-norev' );
        }
 
        if ( $isLatest ) {
            // Short cut! Undoing the current revision means we just restore the old.
            return MutableRevisionRecord::newFromParentRevision( $oldRev );
        }
 
        $newRev = MutableRevisionRecord::newFromParentRevision( $curRev );
 
        // Figure out the roles that need merging by first collecting all roles
        // and then removing the ones that don't.
        $rolesToMerge = array_unique( array_merge(
            $oldRev->getSlotRoles(),
            $undoRev->getSlotRoles(),
            $curRev->getSlotRoles()
        ) );
 
        // Any roles with the same content in $oldRev and $undoRev can be
        // inherited because undo won't change them.
        $rolesToMerge = array_intersect(
            $rolesToMerge, $oldRev->getSlots()->getRolesWithDifferentContent( $undoRev->getSlots() )
        );
        if ( !$rolesToMerge ) {
            throw new ErrorPageError( 'mcrundofailed', 'undo-nochange' );
        }
 
        // Any roles with the same content in $oldRev and $curRev were already reverted
        // and so can be inherited.
        $rolesToMerge = array_intersect(
            $rolesToMerge, $oldRev->getSlots()->getRolesWithDifferentContent( $curRev->getSlots() )
        );
        if ( !$rolesToMerge ) {
            throw new ErrorPageError( 'mcrundofailed', 'undo-nochange' );
        }
 
        // Any roles with the same content in $undoRev and $curRev weren't
        // changed since and so can be reverted to $oldRev.
        $diffRoles = array_intersect(
            $rolesToMerge, $undoRev->getSlots()->getRolesWithDifferentContent( $curRev->getSlots() )
        );
        foreach ( array_diff( $rolesToMerge, $diffRoles ) as $role ) {
            if ( $oldRev->hasSlot( $role ) ) {
                $newRev->inheritSlot( $oldRev->getSlot( $role, RevisionRecord::RAW ) );
            } else {
                $newRev->removeSlot( $role );
            }
        }
        $rolesToMerge = $diffRoles;
 
        // Any slot additions or removals not handled by the above checks can't be undone.
        // There will be only one of the three revisions missing the slot:
        //  - !old means it was added in the undone revisions and modified after.
        //    Should it be removed entirely for the undo, or should the modified version be kept?
        //  - !undo means it was removed in the undone revisions and then readded with different content.
        //    Which content is should be kept, the old or the new?
        //  - !cur means it was changed in the undone revisions and then deleted after.
        //    Did someone delete vandalized content instead of undoing (meaning we should ideally restore
        //    it), or should it stay gone?
        foreach ( $rolesToMerge as $role ) {
            if ( !$oldRev->hasSlot( $role ) || !$undoRev->hasSlot( $role ) || !$curRev->hasSlot( $role ) ) {
                throw new ErrorPageError( 'mcrundofailed', 'undo-failure' );
            }
        }
 
        // Try to merge anything that's left.
        foreach ( $rolesToMerge as $role ) {
            $oldContent = $oldRev->getSlot( $role, RevisionRecord::RAW )->getContent();
            $undoContent = $undoRev->getSlot( $role, RevisionRecord::RAW )->getContent();
            $curContent = $curRev->getSlot( $role, RevisionRecord::RAW )->getContent();
            $newContent = $undoContent->getContentHandler()
                ->getUndoContent( $curContent, $undoContent, $oldContent, $isLatest );
            if ( !$newContent ) {
                throw new ErrorPageError( 'mcrundofailed', 'undo-failure' );
            }
            $newRev->setSlot( SlotRecord::newUnsaved( $role, $newContent ) );
        }
 
        return $newRev;
    }
 
    private function generateDiffOrPreview() {
        $newRev = $this->getNewRevision();
        if ( $newRev->hasSameContent( $this->curRev ) ) {
            throw new ErrorPageError( 'mcrundofailed', 'undo-nochange' );
        }
 
        $diffEngine = new DifferenceEngine( $this->context );
        $diffEngine->setRevisions( $this->curRev, $newRev );
 
        $oldtitle = $this->context->msg( 'currentrev' )->parse();
        $newtitle = $this->context->msg( 'yourtext' )->parse();
 
        if ( $this->getRequest()->getCheck( 'wpPreview' ) ) {
            $this->showPreview( $newRev );
            return '';
        } else {
            $diffText = $diffEngine->getDiff( $oldtitle, $newtitle );
            $diffEngine->showDiffStyle();
            return '<div id="wikiDiff">' . $diffText . '</div>';
        }
    }
 
    private function showPreview( RevisionRecord $rev ) {
        // Mostly copied from EditPage::getPreviewText()
        $out = $this->getOutput();
 
        try {
            $previewHTML = '';
 
            # provide a anchor link to the form
            $continueEditing = '<span class="mw-continue-editing">' .
                '[[#mw-mcrundo-form|' .
                $this->context->getLanguage()->getArrow() . ' ' .
                $this->context->msg( 'continue-editing' )->text() . ']]</span>';
 
            $note = $this->context->msg( 'previewnote' )->plain() . ' ' . $continueEditing;
 
            $parserOptions = $this->page->makeParserOptions( $this->context );
            $parserOptions->setIsPreview( true );
            $parserOptions->setIsSectionPreview( false );
            $parserOptions->enableLimitReport();
 
            $parserOutput = MediaWikiServices::getInstance()->getRevisionRenderer()
                ->getRenderedRevision( $rev, $parserOptions, $this->context->getUser() )
                ->getRevisionParserOutput();
            $previewHTML = $parserOutput->getText( [ 'enableSectionEditLinks' => false ] );
 
            $out->addParserOutputMetadata( $parserOutput );
            if ( count( $parserOutput->getWarnings() ) ) {
                $note .= "\n\n" . implode( "\n\n", $parserOutput->getWarnings() );
            }
        } catch ( MWContentSerializationException $ex ) {
            $m = $this->context->msg(
                'content-failed-to-parse',
                $ex->getMessage()
            );
            $note .= "\n\n" . $m->parse();
            $previewHTML = '';
        }
 
        $previewhead = Html::rawElement(
            'div', [ 'class' => 'previewnote' ],
            Html::element(
                'h2', [ 'id' => 'mw-previewheader' ],
                $this->context->msg( 'preview' )->text()
            ) .
            $out->parseAsInterface( $note ) .
            "<hr />"
        );
 
        $pageViewLang = $this->getTitle()->getPageViewLanguage();
        $attribs = [ 'lang' => $pageViewLang->getHtmlCode(), 'dir' => $pageViewLang->getDir(),
            'class' => 'mw-content-' . $pageViewLang->getDir() ];
        $previewHTML = Html::rawElement( 'div', $attribs, $previewHTML );
 
        $out->addHTML( $previewhead . $previewHTML );
    }
 
    public function onSubmit( $data ) {
        global $wgUseRCPatrol;
 
        if ( !$this->getRequest()->getCheck( 'wpSave' ) ) {
            // Diff or preview
            return false;
        }
 
        $updater = $this->page->getPage()->newPageUpdater( $this->context->getUser() );
        $curRev = $updater->grabParentRevision();
        if ( !$curRev ) {
            throw new ErrorPageError( 'mcrundofailed', 'nopagetext' );
        }
 
        if ( $this->cur !== $curRev->getId() ) {
            return Status::newFatal( 'mcrundo-changed' );
        }
 
        $newRev = $this->getNewRevision();
        if ( !$newRev->hasSameContent( $curRev ) ) {
            // Copy new slots into the PageUpdater, and remove any removed slots.
            // TODO: This interface is awful, there should be a way to just pass $newRev.
            // TODO: MCR: test this once we can store multiple slots
            foreach ( $newRev->getSlots()->getSlots() as $slot ) {
                $updater->setSlot( $slot );
            }
            foreach ( $curRev->getSlotRoles() as $role ) {
                if ( !$newRev->hasSlot( $role ) ) {
                    $updater->removeSlot( $role );
                }
            }
 
            $updater->setOriginalRevisionId( false );
            $updater->setUndidRevisionId( $this->undo );
 
            // TODO: Ugh.
            if ( $wgUseRCPatrol && $this->getTitle()->userCan( 'autopatrol', $this->getUser() ) ) {
                $updater->setRcPatrolStatus( RecentChange::PRC_AUTOPATROLLED );
            }
 
            $updater->saveRevision(
                CommentStoreComment::newUnsavedComment( trim( $this->getRequest()->getVal( 'wpSummary' ) ) ),
                EDIT_AUTOSUMMARY | EDIT_UPDATE
            );
 
            return $updater->getStatus();
        }
 
        return Status::newGood();
    }
 
    protected function usesOOUI() {
        return true;
    }
 
    protected function getFormFields() {
        $request = $this->getRequest();
        $ret = [
            'diff' => [
                'type' => 'info',
                'vertical-label' => true,
                'raw' => true,
                'default' => function () {
                    return $this->generateDiffOrPreview();
                }
            ],
            'summary' => [
                'type' => 'text',
                'id' => 'wpSummary',
                'name' => 'wpSummary',
                'cssclass' => 'mw-summary',
                'label-message' => 'summary',
                'maxlength' => CommentStore::COMMENT_CHARACTER_LIMIT,
                'value' => $request->getVal( 'wpSummary', '' ),
                'size' => 60,
                'spellcheck' => 'true',
            ],
            'summarypreview' => [
                'type' => 'info',
                'label-message' => 'summary-preview',
                'raw' => true,
            ],
        ];
 
        if ( $request->getCheck( 'wpSummary' ) ) {
            $ret['summarypreview']['default'] = Xml::tags( 'div', [ 'class' => 'mw-summary-preview' ],
                Linker::commentBlock( trim( $request->getVal( 'wpSummary' ) ), $this->getTitle(), false )
            );
        } else {
            unset( $ret['summarypreview'] );
        }
 
        return $ret;
    }
 
    protected function alterForm( HTMLForm $form ) {
        $form->setWrapperLegendMsg( 'confirm-mcrundo-title' );
 
        $labelAsPublish = $this->context->getConfig()->get( 'EditSubmitButtonLabelPublish' );
 
        $form->setId( 'mw-mcrundo-form' );
        $form->setSubmitName( 'wpSave' );
        $form->setSubmitTooltip( $labelAsPublish ? 'publish' : 'save' );
        $form->setSubmitTextMsg( $labelAsPublish ? 'publishchanges' : 'savechanges' );
        $form->showCancel( true );
        $form->setCancelTarget( $this->getTitle() );
        $form->addButton( [
            'name' => 'wpPreview',
            'value' => '1',
            'label-message' => 'showpreview',
            'attribs' => Linker::tooltipAndAccesskeyAttribs( 'preview' ),
        ] );
        $form->addButton( [
            'name' => 'wpDiff',
            'value' => '1',
            'label-message' => 'showdiff',
            'attribs' => Linker::tooltipAndAccesskeyAttribs( 'diff' ),
        ] );
 
        $this->addStatePropagationFields( $form );
    }
 
    protected function addStatePropagationFields( HTMLForm $form ) {
        $form->addHiddenField( 'undo', $this->undo );
        $form->addHiddenField( 'undoafter', $this->undoafter );
        $form->addHiddenField( 'cur', $this->curRev->getId() );
    }
 
    public function onSuccess() {
        $this->getOutput()->redirect( $this->getTitle()->getFullURL() );
    }
 
    protected function preText() {
        return '<div style="clear:both"></div>';
    }
}