EditPage.php

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<?php
use MediaWiki\Logger\LoggerFactory;

class EditPage {
    const AS_SUCCESS_UPDATE = 200;

    const AS_SUCCESS_NEW_ARTICLE = 201;

    const AS_HOOK_ERROR = 210;

    const AS_HOOK_ERROR_EXPECTED = 212;

    const AS_BLOCKED_PAGE_FOR_USER = 215;

    const AS_CONTENT_TOO_BIG = 216;

    const AS_READ_ONLY_PAGE_ANON = 218;

    const AS_READ_ONLY_PAGE_LOGGED = 219;

    const AS_READ_ONLY_PAGE = 220;

    const AS_RATE_LIMITED = 221;

    const AS_ARTICLE_WAS_DELETED = 222;

    const AS_NO_CREATE_PERMISSION = 223;

    const AS_BLANK_ARTICLE = 224;

    const AS_CONFLICT_DETECTED = 225;

    const AS_SUMMARY_NEEDED = 226;

    const AS_TEXTBOX_EMPTY = 228;

    const AS_MAX_ARTICLE_SIZE_EXCEEDED = 229;

    const AS_END = 231;

    const AS_SPAM_ERROR = 232;

    const AS_IMAGE_REDIRECT_ANON = 233;

    const AS_IMAGE_REDIRECT_LOGGED = 234;

    const AS_NO_CHANGE_CONTENT_MODEL = 235;

    const AS_SELF_REDIRECT = 236;

    const AS_CHANGE_TAG_ERROR = 237;

    const AS_PARSE_ERROR = 240;

    const AS_CANNOT_USE_CUSTOM_MODEL = 241;

    const EDITFORM_ID = 'editform';

    const POST_EDIT_COOKIE_KEY_PREFIX = 'PostEditRevision';

    const POST_EDIT_COOKIE_DURATION = 1200;

    public $mArticle;
    private $page;

    public $mTitle;

    private $mContextTitle = null;

    public $action = 'submit';

    public $isConflict = false;

    public $isCssJsSubpage = false;

    public $isCssSubpage = false;

    public $isJsSubpage = false;

    public $isWrongCaseCssJsPage = false;

    public $isNew = false;

    public $deletedSinceEdit;

    public $formtype;

    public $firsttime;

    public $lastDelete;

    public $mTokenOk = false;

    public $mTokenOkExceptSuffix = false;

    public $mTriedSave = false;

    public $incompleteForm = false;

    public $tooBig = false;

    public $missingComment = false;

    public $missingSummary = false;

    public $allowBlankSummary = false;

    protected $blankArticle = false;

    protected $allowBlankArticle = false;

    protected $selfRedirect = false;

    protected $allowSelfRedirect = false;

    public $autoSumm = '';

    public $hookError = '';

    public $mParserOutput;

    public $hasPresetSummary = false;

    public $mBaseRevision = false;

    public $mShowSummaryField = true;

    # Form values

    public $save = false;

    public $preview = false;

    public $diff = false;

    public $minoredit = false;

    public $watchthis = false;

    public $recreate = false;

    public $textbox1 = '';

    public $textbox2 = '';

    public $summary = '';

    public $nosummary = false;

    public $edittime = '';

    private $editRevId = null;

    public $section = '';

    public $sectiontitle = '';

    public $starttime = '';

    public $oldid = 0;

    public $parentRevId = 0;

    public $editintro = '';

    public $scrolltop = null;

    public $bot = true;

    public $contentModel = null;

    public $contentFormat = null;

    private $changeTags = null;

    # Placeholders for text injection by hooks (must be HTML)
    # extensions should take care to _append_ to the present value

    public $editFormPageTop = '';
    public $editFormTextTop = '';
    public $editFormTextBeforeContent = '';
    public $editFormTextAfterWarn = '';
    public $editFormTextAfterTools = '';
    public $editFormTextBottom = '';
    public $editFormTextAfterContent = '';
    public $previewTextAfterContent = '';
    public $mPreloadContent = null;

    /* $didSave should be set to true whenever an article was successfully altered. */
    public $didSave = false;
    public $undidRev = 0;

    public $suppressIntro = false;

    protected $edit;

    protected $contentLength = false;

    private $enableApiEditOverride = false;

    public function __construct( Article $article ) {
        $this->mArticle = $article;
        $this->page = $article->getPage(); // model object
        $this->mTitle = $article->getTitle();

        $this->contentModel = $this->mTitle->getContentModel();

        $handler = ContentHandler::getForModelID( $this->contentModel );
        $this->contentFormat = $handler->getDefaultFormat();
    }

    public function getArticle() {
        return $this->mArticle;
    }

    public function getTitle() {
        return $this->mTitle;
    }

    public function setContextTitle( $title ) {
        $this->mContextTitle = $title;
    }

    public function getContextTitle() {
        if ( is_null( $this->mContextTitle ) ) {
            global $wgTitle;
            return $wgTitle;
        } else {
            return $this->mContextTitle;
        }
    }

    public function isSupportedContentModel( $modelId ) {
        return $this->enableApiEditOverride === true ||
            ContentHandler::getForModelID( $modelId )->supportsDirectEditing();
    }

    public function setApiEditOverride( $enableOverride ) {
        $this->enableApiEditOverride = $enableOverride;
    }

    function submit() {
        $this->edit();
    }

    function edit() {
        global $wgOut, $wgRequest, $wgUser;
        // Allow extensions to modify/prevent this form or submission
        if ( !Hooks::run( 'AlternateEdit', [ $this ] ) ) {
            return;
        }

        wfDebug( __METHOD__ . ": enter\n" );

        // If they used redlink=1 and the page exists, redirect to the main article
        if ( $wgRequest->getBool( 'redlink' ) && $this->mTitle->exists() ) {
            $wgOut->redirect( $this->mTitle->getFullURL() );
            return;
        }

        $this->importFormData( $wgRequest );
        $this->firsttime = false;

        if ( wfReadOnly() && $this->save ) {
            // Force preview
            $this->save = false;
            $this->preview = true;
        }

        if ( $this->save ) {
            $this->formtype = 'save';
        } elseif ( $this->preview ) {
            $this->formtype = 'preview';
        } elseif ( $this->diff ) {
            $this->formtype = 'diff';
        } else { # First time through
            $this->firsttime = true;
            if ( $this->previewOnOpen() ) {
                $this->formtype = 'preview';
            } else {
                $this->formtype = 'initial';
            }
        }

        $permErrors = $this->getEditPermissionErrors( $this->save ? 'secure' : 'full' );
        if ( $permErrors ) {
            wfDebug( __METHOD__ . ": User can't edit\n" );
            // Auto-block user's IP if the account was "hard" blocked
            if ( !wfReadOnly() ) {
                $user = $wgUser;
                DeferredUpdates::addCallableUpdate( function () use ( $user ) {
                    $user->spreadAnyEditBlock();
                } );
            }
            $this->displayPermissionsError( $permErrors );

            return;
        }

        $revision = $this->mArticle->getRevisionFetched();
        // Disallow editing revisions with content models different from the current one
        if ( $revision && $revision->getContentModel() !== $this->contentModel ) {
            $this->displayViewSourcePage(
                $this->getContentObject(),
                wfMessage(
                    'contentmodelediterror',
                    $revision->getContentModel(),
                    $this->contentModel
                )->plain()
            );
            return;
        }

        $this->isConflict = false;
        // css / js subpages of user pages get a special treatment
        $this->isCssJsSubpage = $this->mTitle->isCssJsSubpage();
        $this->isCssSubpage = $this->mTitle->isCssSubpage();
        $this->isJsSubpage = $this->mTitle->isJsSubpage();
        // @todo FIXME: Silly assignment.
        $this->isWrongCaseCssJsPage = $this->isWrongCaseCssJsPage();

        # Show applicable editing introductions
        if ( $this->formtype == 'initial' || $this->firsttime ) {
            $this->showIntro();
        }

        # Attempt submission here.  This will check for edit conflicts,
        # and redundantly check for locked database, blocked IPs, etc.
        # that edit() already checked just in case someone tries to sneak
        # in the back door with a hand-edited submission URL.

        if ( 'save' == $this->formtype ) {
            $resultDetails = null;
            $status = $this->attemptSave( $resultDetails );
            if ( !$this->handleStatus( $status, $resultDetails ) ) {
                return;
            }
        }

        # First time through: get contents, set time for conflict
        # checking, etc.
        if ( 'initial' == $this->formtype || $this->firsttime ) {
            if ( $this->initialiseForm() === false ) {
                $this->noSuchSectionPage();
                return;
            }

            if ( !$this->mTitle->getArticleID() ) {
                Hooks::run( 'EditFormPreloadText', [ &$this->textbox1, &$this->mTitle ] );
            } else {
                Hooks::run( 'EditFormInitialText', [ $this ] );
            }

        }

        $this->showEditForm();
    }

    protected function getEditPermissionErrors( $rigor = 'secure' ) {
        global $wgUser;

        $permErrors = $this->mTitle->getUserPermissionsErrors( 'edit', $wgUser, $rigor );
        # Can this title be created?
        if ( !$this->mTitle->exists() ) {
            $permErrors = array_merge(
                $permErrors,
                wfArrayDiff2(
                    $this->mTitle->getUserPermissionsErrors( 'create', $wgUser, $rigor ),
                    $permErrors
                )
            );
        }
        # Ignore some permissions errors when a user is just previewing/viewing diffs
        $remove = [];
        foreach ( $permErrors as $error ) {
            if ( ( $this->preview || $this->diff )
                && ( $error[0] == 'blockedtext' || $error[0] == 'autoblockedtext' )
            ) {
                $remove[] = $error;
            }
        }
        $permErrors = wfArrayDiff2( $permErrors, $remove );

        return $permErrors;
    }

    protected function displayPermissionsError( array $permErrors ) {
        global $wgRequest, $wgOut;

        if ( $wgRequest->getBool( 'redlink' ) ) {
            // The edit page was reached via a red link.
            // Redirect to the article page and let them click the edit tab if
            // they really want a permission error.
            $wgOut->redirect( $this->mTitle->getFullURL() );
            return;
        }

        $content = $this->getContentObject();

        # Use the normal message if there's nothing to display
        if ( $this->firsttime && ( !$content || $content->isEmpty() ) ) {
            $action = $this->mTitle->exists() ? 'edit' :
                ( $this->mTitle->isTalkPage() ? 'createtalk' : 'createpage' );
            throw new PermissionsError( $action, $permErrors );
        }

        $this->displayViewSourcePage(
            $content,
            $wgOut->formatPermissionsErrorMessage( $permErrors, 'edit' )
        );
    }

    protected function displayViewSourcePage( Content $content, $errorMessage = '' ) {
        global $wgOut;

        Hooks::run( 'EditPage::showReadOnlyForm:initial', [ $this, &$wgOut ] );

        $wgOut->setRobotPolicy( 'noindex,nofollow' );
        $wgOut->setPageTitle( wfMessage(
            'viewsource-title',
            $this->getContextTitle()->getPrefixedText()
        ) );
        $wgOut->addBacklinkSubtitle( $this->getContextTitle() );
        $wgOut->addHTML( $this->editFormPageTop );
        $wgOut->addHTML( $this->editFormTextTop );

        if ( $errorMessage !== '' ) {
            $wgOut->addWikiText( $errorMessage );
            $wgOut->addHTML( "<hr />\n" );
        }

        # If the user made changes, preserve them when showing the markup
        # (This happens when a user is blocked during edit, for instance)
        if ( !$this->firsttime ) {
            $text = $this->textbox1;
            $wgOut->addWikiMsg( 'viewyourtext' );
        } else {
            try {
                $text = $this->toEditText( $content );
            } catch ( MWException $e ) {
                # Serialize using the default format if the content model is not supported
                # (e.g. for an old revision with a different model)
                $text = $content->serialize();
            }
            $wgOut->addWikiMsg( 'viewsourcetext' );
        }

        $wgOut->addHTML( $this->editFormTextBeforeContent );
        $this->showTextbox( $text, 'wpTextbox1', [ 'readonly' ] );
        $wgOut->addHTML( $this->editFormTextAfterContent );

        $wgOut->addHTML( Html::rawElement( 'div', [ 'class' => 'templatesUsed' ],
            Linker::formatTemplates( $this->getTemplates() ) ) );

        $wgOut->addModules( 'mediawiki.action.edit.collapsibleFooter' );

        $wgOut->addHTML( $this->editFormTextBottom );
        if ( $this->mTitle->exists() ) {
            $wgOut->returnToMain( null, $this->mTitle );
        }
    }

    protected function previewOnOpen() {
        global $wgRequest, $wgUser, $wgPreviewOnOpenNamespaces;
        if ( $wgRequest->getVal( 'preview' ) == 'yes' ) {
            // Explicit override from request
            return true;
        } elseif ( $wgRequest->getVal( 'preview' ) == 'no' ) {
            // Explicit override from request
            return false;
        } elseif ( $this->section == 'new' ) {
            // Nothing *to* preview for new sections
            return false;
        } elseif ( ( $wgRequest->getVal( 'preload' ) !== null || $this->mTitle->exists() )
            && $wgUser->getOption( 'previewonfirst' )
        ) {
            // Standard preference behavior
            return true;
        } elseif ( !$this->mTitle->exists()
            && isset( $wgPreviewOnOpenNamespaces[$this->mTitle->getNamespace()] )
            && $wgPreviewOnOpenNamespaces[$this->mTitle->getNamespace()]
        ) {
            // Categories are special
            return true;
        } else {
            return false;
        }
    }

    protected function isWrongCaseCssJsPage() {
        if ( $this->mTitle->isCssJsSubpage() ) {
            $name = $this->mTitle->getSkinFromCssJsSubpage();
            $skins = array_merge(
                array_keys( Skin::getSkinNames() ),
                [ 'common' ]
            );
            return !in_array( $name, $skins )
                && in_array( strtolower( $name ), $skins );
        } else {
            return false;
        }
    }

    protected function isSectionEditSupported() {
        $contentHandler = ContentHandler::getForTitle( $this->mTitle );
        return $contentHandler->supportsSections();
    }

    function importFormData( &$request ) {
        global $wgContLang, $wgUser;

        # Section edit can come from either the form or a link
        $this->section = $request->getVal( 'wpSection', $request->getVal( 'section' ) );

        if ( $this->section !== null && $this->section !== '' && !$this->isSectionEditSupported() ) {
            throw new ErrorPageError( 'sectioneditnotsupported-title', 'sectioneditnotsupported-text' );
        }

        $this->isNew = !$this->mTitle->exists() || $this->section == 'new';

        if ( $request->wasPosted() ) {
            # These fields need to be checked for encoding.
            # Also remove trailing whitespace, but don't remove _initial_
            # whitespace from the text boxes. This may be significant formatting.
            $this->textbox1 = $this->safeUnicodeInput( $request, 'wpTextbox1' );
            if ( !$request->getCheck( 'wpTextbox2' ) ) {
                // Skip this if wpTextbox2 has input, it indicates that we came
                // from a conflict page with raw page text, not a custom form
                // modified by subclasses
                $textbox1 = $this->importContentFormData( $request );
                if ( $textbox1 !== null ) {
                    $this->textbox1 = $textbox1;
                }
            }

            # Truncate for whole multibyte characters
            $this->summary = $wgContLang->truncate( $request->getText( 'wpSummary' ), 255 );

            # If the summary consists of a heading, e.g. '==Foobar==', extract the title from the
            # header syntax, e.g. 'Foobar'. This is mainly an issue when we are using wpSummary for
            # section titles.
            $this->summary = preg_replace( '/^\s*=+\s*(.*?)\s*=+\s*$/', '$1', $this->summary );

            # Treat sectiontitle the same way as summary.
            # Note that wpSectionTitle is not yet a part of the actual edit form, as wpSummary is
            # currently doing double duty as both edit summary and section title. Right now this
            # is just to allow API edits to work around this limitation, but this should be
            # incorporated into the actual edit form when EditPage is rewritten (Bugs 18654, 26312).
            $this->sectiontitle = $wgContLang->truncate( $request->getText( 'wpSectionTitle' ), 255 );
            $this->sectiontitle = preg_replace( '/^\s*=+\s*(.*?)\s*=+\s*$/', '$1', $this->sectiontitle );

            $this->edittime = $request->getVal( 'wpEdittime' );
            $this->editRevId = $request->getIntOrNull( 'editRevId' );
            $this->starttime = $request->getVal( 'wpStarttime' );

            $undidRev = $request->getInt( 'wpUndidRevision' );
            if ( $undidRev ) {
                $this->undidRev = $undidRev;
            }

            $this->scrolltop = $request->getIntOrNull( 'wpScrolltop' );

            if ( $this->textbox1 === '' && $request->getVal( 'wpTextbox1' ) === null ) {
                // wpTextbox1 field is missing, possibly due to being "too big"
                // according to some filter rules such as Suhosin's setting for
                // suhosin.request.max_value_length (d'oh)
                $this->incompleteForm = true;
            } else {
                // If we receive the last parameter of the request, we can fairly
                // claim the POST request has not been truncated.

                // TODO: softened the check for cutover.  Once we determine
                // that it is safe, we should complete the transition by
                // removing the "edittime" clause.
                $this->incompleteForm = ( !$request->getVal( 'wpUltimateParam' )
                    && is_null( $this->edittime ) );
            }
            if ( $this->incompleteForm ) {
                # If the form is incomplete, force to preview.
                wfDebug( __METHOD__ . ": Form data appears to be incomplete\n" );
                wfDebug( "POST DATA: " . var_export( $_POST, true ) . "\n" );
                $this->preview = true;
            } else {
                $this->preview = $request->getCheck( 'wpPreview' );
                $this->diff = $request->getCheck( 'wpDiff' );

                // Remember whether a save was requested, so we can indicate
                // if we forced preview due to session failure.
                $this->mTriedSave = !$this->preview;

                if ( $this->tokenOk( $request ) ) {
                    # Some browsers will not report any submit button
                    # if the user hits enter in the comment box.
                    # The unmarked state will be assumed to be a save,
                    # if the form seems otherwise complete.
                    wfDebug( __METHOD__ . ": Passed token check.\n" );
                } elseif ( $this->diff ) {
                    # Failed token check, but only requested "Show Changes".
                    wfDebug( __METHOD__ . ": Failed token check; Show Changes requested.\n" );
                } else {
                    # Page might be a hack attempt posted from
                    # an external site. Preview instead of saving.
                    wfDebug( __METHOD__ . ": Failed token check; forcing preview\n" );
                    $this->preview = true;
                }
            }
            $this->save = !$this->preview && !$this->diff;
            if ( !preg_match( '/^\d{14}$/', $this->edittime ) ) {
                $this->edittime = null;
            }

            if ( !preg_match( '/^\d{14}$/', $this->starttime ) ) {
                $this->starttime = null;
            }

            $this->recreate = $request->getCheck( 'wpRecreate' );

            $this->minoredit = $request->getCheck( 'wpMinoredit' );
            $this->watchthis = $request->getCheck( 'wpWatchthis' );

            # Don't force edit summaries when a user is editing their own user or talk page
            if ( ( $this->mTitle->mNamespace == NS_USER || $this->mTitle->mNamespace == NS_USER_TALK )
                && $this->mTitle->getText() == $wgUser->getName()
            ) {
                $this->allowBlankSummary = true;
            } else {
                $this->allowBlankSummary = $request->getBool( 'wpIgnoreBlankSummary' )
                    || !$wgUser->getOption( 'forceeditsummary' );
            }

            $this->autoSumm = $request->getText( 'wpAutoSummary' );

            $this->allowBlankArticle = $request->getBool( 'wpIgnoreBlankArticle' );
            $this->allowSelfRedirect = $request->getBool( 'wpIgnoreSelfRedirect' );

            $changeTags = $request->getVal( 'wpChangeTags' );
            if ( is_null( $changeTags ) || $changeTags === '' ) {
                $this->changeTags = [];
            } else {
                $this->changeTags = array_filter( array_map( 'trim', explode( ',',
                    $changeTags ) ) );
            }
        } else {
            # Not a posted form? Start with nothing.
            wfDebug( __METHOD__ . ": Not a posted form.\n" );
            $this->textbox1 = '';
            $this->summary = '';
            $this->sectiontitle = '';
            $this->edittime = '';
            $this->editRevId = null;
            $this->starttime = wfTimestampNow();
            $this->edit = false;
            $this->preview = false;
            $this->save = false;
            $this->diff = false;
            $this->minoredit = false;
            // Watch may be overridden by request parameters
            $this->watchthis = $request->getBool( 'watchthis', false );
            $this->recreate = false;

            // When creating a new section, we can preload a section title by passing it as the
            // preloadtitle parameter in the URL (Bug 13100)
            if ( $this->section == 'new' && $request->getVal( 'preloadtitle' ) ) {
                $this->sectiontitle = $request->getVal( 'preloadtitle' );
                // Once wpSummary isn't being use for setting section titles, we should delete this.
                $this->summary = $request->getVal( 'preloadtitle' );
            } elseif ( $this->section != 'new' && $request->getVal( 'summary' ) ) {
                $this->summary = $request->getText( 'summary' );
                if ( $this->summary !== '' ) {
                    $this->hasPresetSummary = true;
                }
            }

            if ( $request->getVal( 'minor' ) ) {
                $this->minoredit = true;
            }
        }

        $this->oldid = $request->getInt( 'oldid' );
        $this->parentRevId = $request->getInt( 'parentRevId' );

        $this->bot = $request->getBool( 'bot', true );
        $this->nosummary = $request->getBool( 'nosummary' );

        // May be overridden by revision.
        $this->contentModel = $request->getText( 'model', $this->contentModel );
        // May be overridden by revision.
        $this->contentFormat = $request->getText( 'format', $this->contentFormat );

        if ( !ContentHandler::getForModelID( $this->contentModel )
            ->isSupportedFormat( $this->contentFormat )
        ) {
            throw new ErrorPageError(
                'editpage-notsupportedcontentformat-title',
                'editpage-notsupportedcontentformat-text',
                [ $this->contentFormat, ContentHandler::getLocalizedName( $this->contentModel ) ]
            );
        }

        $this->editintro = $request->getText( 'editintro',
            // Custom edit intro for new sections
            $this->section === 'new' ? 'MediaWiki:addsection-editintro' : '' );

        // Allow extensions to modify form data
        Hooks::run( 'EditPage::importFormData', [ $this, $request ] );

    }

    protected function importContentFormData( &$request ) {
        return; // Don't do anything, EditPage already extracted wpTextbox1
    }

    function initialiseForm() {
        global $wgUser;
        $this->edittime = $this->page->getTimestamp();
        $this->editRevId = $this->page->getLatest();

        $content = $this->getContentObject( false ); # TODO: track content object?!
        if ( $content === false ) {
            return false;
        }
        $this->textbox1 = $this->toEditText( $content );

        // activate checkboxes if user wants them to be always active
        # Sort out the "watch" checkbox
        if ( $wgUser->getOption( 'watchdefault' ) ) {
            # Watch all edits
            $this->watchthis = true;
        } elseif ( $wgUser->getOption( 'watchcreations' ) && !$this->mTitle->exists() ) {
            # Watch creations
            $this->watchthis = true;
        } elseif ( $wgUser->isWatched( $this->mTitle ) ) {
            # Already watched
            $this->watchthis = true;
        }
        if ( $wgUser->getOption( 'minordefault' ) && !$this->isNew ) {
            $this->minoredit = true;
        }
        if ( $this->textbox1 === false ) {
            return false;
        }
        return true;
    }

    protected function getContentObject( $def_content = null ) {
        global $wgOut, $wgRequest, $wgUser, $wgContLang;

        $content = false;

        // For message page not locally set, use the i18n message.
        // For other non-existent articles, use preload text if any.
        if ( !$this->mTitle->exists() || $this->section == 'new' ) {
            if ( $this->mTitle->getNamespace() == NS_MEDIAWIKI && $this->section != 'new' ) {
                # If this is a system message, get the default text.
                $msg = $this->mTitle->getDefaultMessageText();

                $content = $this->toEditContent( $msg );
            }
            if ( $content === false ) {
                # If requested, preload some text.
                $preload = $wgRequest->getVal( 'preload',
                    // Custom preload text for new sections
                    $this->section === 'new' ? 'MediaWiki:addsection-preload' : '' );
                $params = $wgRequest->getArray( 'preloadparams', [] );

                $content = $this->getPreloadedContent( $preload, $params );
            }
        // For existing pages, get text based on "undo" or section parameters.
        } else {
            if ( $this->section != '' ) {
                // Get section edit text (returns $def_text for invalid sections)
                $orig = $this->getOriginalContent( $wgUser );
                $content = $orig ? $orig->getSection( $this->section ) : null;

                if ( !$content ) {
                    $content = $def_content;
                }
            } else {
                $undoafter = $wgRequest->getInt( 'undoafter' );
                $undo = $wgRequest->getInt( 'undo' );

                if ( $undo > 0 && $undoafter > 0 ) {
                    $undorev = Revision::newFromId( $undo );
                    $oldrev = Revision::newFromId( $undoafter );

                    # Sanity check, make sure it's the right page,
                    # the revisions exist and they were not deleted.
                    # Otherwise, $content will be left as-is.
                    if ( !is_null( $undorev ) && !is_null( $oldrev ) &&
                        !$undorev->isDeleted( Revision::DELETED_TEXT ) &&
                        !$oldrev->isDeleted( Revision::DELETED_TEXT )
                    ) {
                        $content = $this->page->getUndoContent( $undorev, $oldrev );

                        if ( $content === false ) {
                            # Warn the user that something went wrong
                            $undoMsg = 'failure';
                        } else {
                            $oldContent = $this->page->getContent( Revision::RAW );
                            $popts = ParserOptions::newFromUserAndLang( $wgUser, $wgContLang );
                            $newContent = $content->preSaveTransform( $this->mTitle, $wgUser, $popts );

                            if ( $newContent->equals( $oldContent ) ) {
                                # Tell the user that the undo results in no change,
                                # i.e. the revisions were already undone.
                                $undoMsg = 'nochange';
                                $content = false;
                            } else {
                                # Inform the user of our success and set an automatic edit summary
                                $undoMsg = 'success';

                                # If we just undid one rev, use an autosummary
                                $firstrev = $oldrev->getNext();
                                if ( $firstrev && $firstrev->getId() == $undo ) {
                                    $userText = $undorev->getUserText();
                                    if ( $userText === '' ) {
                                        $undoSummary = wfMessage(
                                            'undo-summary-username-hidden',
                                            $undo
                                        )->inContentLanguage()->text();
                                    } else {
                                        $undoSummary = wfMessage(
                                            'undo-summary',
                                            $undo,
                                            $userText
                                        )->inContentLanguage()->text();
                                    }
                                    if ( $this->summary === '' ) {
                                        $this->summary = $undoSummary;
                                    } else {
                                        $this->summary = $undoSummary . wfMessage( 'colon-separator' )
                                            ->inContentLanguage()->text() . $this->summary;
                                    }
                                    $this->undidRev = $undo;
                                }
                                $this->formtype = 'diff';
                            }
                        }
                    } else {
                        // Failed basic sanity checks.
                        // Older revisions may have been removed since the link
                        // was created, or we may simply have got bogus input.
                        $undoMsg = 'norev';
                    }

                    // Messages: undo-success, undo-failure, undo-norev, undo-nochange
                    $class = ( $undoMsg == 'success' ? '' : 'error ' ) . "mw-undo-{$undoMsg}";
                    $this->editFormPageTop .= $wgOut->parse( "<div class=\"{$class}\">" .
                        wfMessage( 'undo-' . $undoMsg )->plain() . '</div>', true, /* interface */true );
                }

                if ( $content === false ) {
                    $content = $this->getOriginalContent( $wgUser );
                }
            }
        }

        return $content;
    }

    private function getOriginalContent( User $user ) {
        if ( $this->section == 'new' ) {
            return $this->getCurrentContent();
        }
        $revision = $this->mArticle->getRevisionFetched();
        if ( $revision === null ) {
            if ( !$this->contentModel ) {
                $this->contentModel = $this->getTitle()->getContentModel();
            }
            $handler = ContentHandler::getForModelID( $this->contentModel );

            return $handler->makeEmptyContent();
        }
        $content = $revision->getContent( Revision::FOR_THIS_USER, $user );
        return $content;
    }

    public function getParentRevId() {
        if ( $this->parentRevId ) {
            return $this->parentRevId;
        } else {
            return $this->mArticle->getRevIdFetched();
        }
    }

    protected function getCurrentContent() {
        $rev = $this->page->getRevision();
        $content = $rev ? $rev->getContent( Revision::RAW ) : null;

        if ( $content === false || $content === null ) {
            if ( !$this->contentModel ) {
                $this->contentModel = $this->getTitle()->getContentModel();
            }
            $handler = ContentHandler::getForModelID( $this->contentModel );

            return $handler->makeEmptyContent();
        } else {
            // Content models should always be the same since we error
            // out if they are different before this point.
            $logger = LoggerFactory::getInstance( 'editpage' );
            if ( $this->contentModel !== $rev->getContentModel() ) {
                $logger->warning( "Overriding content model from current edit {prev} to {new}", [
                    'prev' => $this->contentModel,
                    'new' => $rev->getContentModel(),
                    'title' => $this->getTitle()->getPrefixedDBkey(),
                    'method' => __METHOD__
                ] );
                $this->contentModel = $rev->getContentModel();
            }

            // Given that the content models should match, the current selected
            // format should be supported.
            if ( !$content->isSupportedFormat( $this->contentFormat ) ) {
                $logger->warning( "Current revision content format unsupported. Overriding {prev} to {new}", [

                    'prev' => $this->contentFormat,
                    'new' => $rev->getContentFormat(),
                    'title' => $this->getTitle()->getPrefixedDBkey(),
                    'method' => __METHOD__
                ] );
                $this->contentFormat = $rev->getContentFormat();
            }

            return $content;
        }
    }

    public function setPreloadedContent( Content $content ) {
        $this->mPreloadContent = $content;
    }

    protected function getPreloadedContent( $preload, $params = [] ) {
        global $wgUser;

        if ( !empty( $this->mPreloadContent ) ) {
            return $this->mPreloadContent;
        }

        $handler = ContentHandler::getForModelID( $this->contentModel );

        if ( $preload === '' ) {
            return $handler->makeEmptyContent();
        }

        $title = Title::newFromText( $preload );
        # Check for existence to avoid getting MediaWiki:Noarticletext
        if ( $title === null || !$title->exists() || !$title->userCan( 'read', $wgUser ) ) {
            // TODO: somehow show a warning to the user!
            return $handler->makeEmptyContent();
        }

        $page = WikiPage::factory( $title );
        if ( $page->isRedirect() ) {
            $title = $page->getRedirectTarget();
            # Same as before
            if ( $title === null || !$title->exists() || !$title->userCan( 'read', $wgUser ) ) {
                // TODO: somehow show a warning to the user!
                return $handler->makeEmptyContent();
            }
            $page = WikiPage::factory( $title );
        }

        $parserOptions = ParserOptions::newFromUser( $wgUser );
        $content = $page->getContent( Revision::RAW );

        if ( !$content ) {
            // TODO: somehow show a warning to the user!
            return $handler->makeEmptyContent();
        }

        if ( $content->getModel() !== $handler->getModelID() ) {
            $converted = $content->convert( $handler->getModelID() );

            if ( !$converted ) {
                // TODO: somehow show a warning to the user!
                wfDebug( "Attempt to preload incompatible content: " .
                    "can't convert " . $content->getModel() .
                    " to " . $handler->getModelID() );

                return $handler->makeEmptyContent();
            }

            $content = $converted;
        }

        return $content->preloadTransform( $title, $parserOptions, $params );
    }

    function tokenOk( &$request ) {
        global $wgUser;
        $token = $request->getVal( 'wpEditToken' );
        $this->mTokenOk = $wgUser->matchEditToken( $token );
        $this->mTokenOkExceptSuffix = $wgUser->matchEditTokenNoSuffix( $token );
        return $this->mTokenOk;
    }

    protected function setPostEditCookie( $statusValue ) {
        $revisionId = $this->page->getLatest();
        $postEditKey = self::POST_EDIT_COOKIE_KEY_PREFIX . $revisionId;

        $val = 'saved';
        if ( $statusValue == self::AS_SUCCESS_NEW_ARTICLE ) {
            $val = 'created';
        } elseif ( $this->oldid ) {
            $val = 'restored';
        }

        $response = RequestContext::getMain()->getRequest()->response();
        $response->setCookie( $postEditKey, $val, time() + self::POST_EDIT_COOKIE_DURATION, [
            'httpOnly' => false,
        ] );
    }

    public function attemptSave( &$resultDetails = false ) {
        global $wgUser;

        # Allow bots to exempt some edits from bot flagging
        $bot = $wgUser->isAllowed( 'bot' ) && $this->bot;
        $status = $this->internalAttemptSave( $resultDetails, $bot );

        Hooks::run( 'EditPage::attemptSave:after', [ $this, $status, $resultDetails ] );

        return $status;
    }

    private function handleStatus( Status $status, $resultDetails ) {
        global $wgUser, $wgOut;

        if ( $status->value == self::AS_SUCCESS_UPDATE
            || $status->value == self::AS_SUCCESS_NEW_ARTICLE
        ) {
            $this->didSave = true;
            if ( !$resultDetails['nullEdit'] ) {
                $this->setPostEditCookie( $status->value );
            }
        }

        // "wpExtraQueryRedirect" is a hidden input to modify
        // after save URL and is not used by actual edit form
        $request = RequestContext::getMain()->getRequest();
        $extraQueryRedirect = $request->getVal( 'wpExtraQueryRedirect' );

        switch ( $status->value ) {
            case self::AS_HOOK_ERROR_EXPECTED:
            case self::AS_CONTENT_TOO_BIG:
            case self::AS_ARTICLE_WAS_DELETED:
            case self::AS_CONFLICT_DETECTED:
            case self::AS_SUMMARY_NEEDED:
            case self::AS_TEXTBOX_EMPTY:
            case self::AS_MAX_ARTICLE_SIZE_EXCEEDED:
            case self::AS_END:
            case self::AS_BLANK_ARTICLE:
            case self::AS_SELF_REDIRECT:
                return true;

            case self::AS_HOOK_ERROR:
                return false;

            case self::AS_CANNOT_USE_CUSTOM_MODEL:
            case self::AS_PARSE_ERROR:
                $wgOut->addWikiText( '<div class="error">' . $status->getWikiText() . '</div>' );
                return true;

            case self::AS_SUCCESS_NEW_ARTICLE:
                $query = $resultDetails['redirect'] ? 'redirect=no' : '';
                if ( $extraQueryRedirect ) {
                    if ( $query === '' ) {
                        $query = $extraQueryRedirect;
                    } else {
                        $query = $query . '&' . $extraQueryRedirect;
                    }
                }
                $anchor = isset( $resultDetails['sectionanchor'] ) ? $resultDetails['sectionanchor'] : '';
                $wgOut->redirect( $this->mTitle->getFullURL( $query ) . $anchor );
                return false;

            case self::AS_SUCCESS_UPDATE:
                $extraQuery = '';
                $sectionanchor = $resultDetails['sectionanchor'];

                // Give extensions a chance to modify URL query on update
                Hooks::run(
                    'ArticleUpdateBeforeRedirect',
                    [ $this->mArticle, &$sectionanchor, &$extraQuery ]
                );

                if ( $resultDetails['redirect'] ) {
                    if ( $extraQuery == '' ) {
                        $extraQuery = 'redirect=no';
                    } else {
                        $extraQuery = 'redirect=no&' . $extraQuery;
                    }
                }
                if ( $extraQueryRedirect ) {
                    if ( $extraQuery === '' ) {
                        $extraQuery = $extraQueryRedirect;
                    } else {
                        $extraQuery = $extraQuery . '&' . $extraQueryRedirect;
                    }
                }

                $wgOut->redirect( $this->mTitle->getFullURL( $extraQuery ) . $sectionanchor );
                return false;

            case self::AS_SPAM_ERROR:
                $this->spamPageWithContent( $resultDetails['spam'] );
                return false;

            case self::AS_BLOCKED_PAGE_FOR_USER:
                throw new UserBlockedError( $wgUser->getBlock() );

            case self::AS_IMAGE_REDIRECT_ANON:
            case self::AS_IMAGE_REDIRECT_LOGGED:
                throw new PermissionsError( 'upload' );

            case self::AS_READ_ONLY_PAGE_ANON:
            case self::AS_READ_ONLY_PAGE_LOGGED:
                throw new PermissionsError( 'edit' );

            case self::AS_READ_ONLY_PAGE:
                throw new ReadOnlyError;

            case self::AS_RATE_LIMITED:
                throw new ThrottledError();

            case self::AS_NO_CREATE_PERMISSION:
                $permission = $this->mTitle->isTalkPage() ? 'createtalk' : 'createpage';
                throw new PermissionsError( $permission );

            case self::AS_NO_CHANGE_CONTENT_MODEL:
                throw new PermissionsError( 'editcontentmodel' );

            default:
                // We don't recognize $status->value. The only way that can happen
                // is if an extension hook aborted from inside ArticleSave.
                // Render the status object into $this->hookError
                // FIXME this sucks, we should just use the Status object throughout
                $this->hookError = '<div class="error">' . $status->getWikiText() .
                    '</div>';
                return true;
        }
    }

    protected function runPostMergeFilters( Content $content, Status $status, User $user ) {
        // Run old style post-section-merge edit filter
        if ( !ContentHandler::runLegacyHooks( 'EditFilterMerged',
            [ $this, $content, &$this->hookError, $this->summary ] )
        ) {
            # Error messages etc. could be handled within the hook...
            $status->fatal( 'hookaborted' );
            $status->value = self::AS_HOOK_ERROR;
            return false;
        } elseif ( $this->hookError != '' ) {
            # ...or the hook could be expecting us to produce an error
            $status->fatal( 'hookaborted' );
            $status->value = self::AS_HOOK_ERROR_EXPECTED;
            return false;
        }

        // Run new style post-section-merge edit filter
        if ( !Hooks::run( 'EditFilterMergedContent',
                [ $this->mArticle->getContext(), $content, $status, $this->summary,
                $user, $this->minoredit ] )
        ) {
            # Error messages etc. could be handled within the hook...
            if ( $status->isGood() ) {
                $status->fatal( 'hookaborted' );
                // Not setting $this->hookError here is a hack to allow the hook
                // to cause a return to the edit page without $this->hookError
                // being set. This is used by ConfirmEdit to display a captcha
                // without any error message cruft.
            } else {
                $this->hookError = $status->getWikiText();
            }
            // Use the existing $status->value if the hook set it
            if ( !$status->value ) {
                $status->value = self::AS_HOOK_ERROR;
            }
            return false;
        } elseif ( !$status->isOK() ) {
            # ...or the hook could be expecting us to produce an error
            // FIXME this sucks, we should just use the Status object throughout
            $this->hookError = $status->getWikiText();
            $status->fatal( 'hookaborted' );
            $status->value = self::AS_HOOK_ERROR_EXPECTED;
            return false;
        }

        return true;
    }

    private function newSectionSummary( &$sectionanchor = null ) {
        global $wgParser;

        if ( $this->sectiontitle !== '' ) {
            $sectionanchor = $wgParser->guessLegacySectionNameFromWikiText( $this->sectiontitle );
            // If no edit summary was specified, create one automatically from the section
            // title and have it link to the new section. Otherwise, respect the summary as
            // passed.
            if ( $this->summary === '' ) {
                $cleanSectionTitle = $wgParser->stripSectionName( $this->sectiontitle );
                return wfMessage( 'newsectionsummary' )
                    ->rawParams( $cleanSectionTitle )->inContentLanguage()->text();
            }
        } elseif ( $this->summary !== '' ) {
            $sectionanchor = $wgParser->guessLegacySectionNameFromWikiText( $this->summary );
            # This is a new section, so create a link to the new section
            # in the revision summary.
            $cleanSummary = $wgParser->stripSectionName( $this->summary );
            return wfMessage( 'newsectionsummary' )
                ->rawParams( $cleanSummary )->inContentLanguage()->text();
        }
        return $this->summary;
    }

    function internalAttemptSave( &$result, $bot = false ) {
        global $wgUser, $wgRequest, $wgParser, $wgMaxArticleSize;
        global $wgContentHandlerUseDB;

        $status = Status::newGood();

        if ( !Hooks::run( 'EditPage::attemptSave', [ $this ] ) ) {
            wfDebug( "Hook 'EditPage::attemptSave' aborted article saving\n" );
            $status->fatal( 'hookaborted' );
            $status->value = self::AS_HOOK_ERROR;
            return $status;
        }

        $spam = $wgRequest->getText( 'wpAntispam' );
        if ( $spam !== '' ) {
            wfDebugLog(
                'SimpleAntiSpam',
                $wgUser->getName() .
                ' editing "' .
                $this->mTitle->getPrefixedText() .
                '" submitted bogus field "' .
                $spam .
                '"'
            );
            $status->fatal( 'spamprotectionmatch', false );
            $status->value = self::AS_SPAM_ERROR;
            return $status;
        }

        try {
            # Construct Content object
            $textbox_content = $this->toEditContent( $this->textbox1 );
        } catch ( MWContentSerializationException $ex ) {
            $status->fatal(
                'content-failed-to-parse',
                $this->contentModel,
                $this->contentFormat,
                $ex->getMessage()
            );
            $status->value = self::AS_PARSE_ERROR;
            return $status;
        }

        # Check image redirect
        if ( $this->mTitle->getNamespace() == NS_FILE &&
            $textbox_content->isRedirect() &&
            !$wgUser->isAllowed( 'upload' )
        ) {
                $code = $wgUser->isAnon() ? self::AS_IMAGE_REDIRECT_ANON : self::AS_IMAGE_REDIRECT_LOGGED;
                $status->setResult( false, $code );

                return $status;
        }

        # Check for spam
        $match = self::matchSummarySpamRegex( $this->summary );
        if ( $match === false && $this->section == 'new' ) {
            # $wgSpamRegex is enforced on this new heading/summary because, unlike
            # regular summaries, it is added to the actual wikitext.
            if ( $this->sectiontitle !== '' ) {
                # This branch is taken when the API is used with the 'sectiontitle' parameter.
                $match = self::matchSpamRegex( $this->sectiontitle );
            } else {
                # This branch is taken when the "Add Topic" user interface is used, or the API
                # is used with the 'summary' parameter.
                $match = self::matchSpamRegex( $this->summary );
            }
        }
        if ( $match === false ) {
            $match = self::matchSpamRegex( $this->textbox1 );
        }
        if ( $match !== false ) {
            $result['spam'] = $match;
            $ip = $wgRequest->getIP();
            $pdbk = $this->mTitle->getPrefixedDBkey();
            $match = str_replace( "\n", '', $match );
            wfDebugLog( 'SpamRegex', "$ip spam regex hit [[$pdbk]]: \"$match\"" );
            $status->fatal( 'spamprotectionmatch', $match );
            $status->value = self::AS_SPAM_ERROR;
            return $status;
        }
        if ( !Hooks::run(
            'EditFilter',
            [ $this, $this->textbox1, $this->section, &$this->hookError, $this->summary ] )
        ) {
            # Error messages etc. could be handled within the hook...
            $status->fatal( 'hookaborted' );
            $status->value = self::AS_HOOK_ERROR;
            return $status;
        } elseif ( $this->hookError != '' ) {
            # ...or the hook could be expecting us to produce an error
            $status->fatal( 'hookaborted' );
            $status->value = self::AS_HOOK_ERROR_EXPECTED;
            return $status;
        }

        if ( $wgUser->isBlockedFrom( $this->mTitle, false ) ) {
            // Auto-block user's IP if the account was "hard" blocked
            if ( !wfReadOnly() ) {
                $wgUser->spreadAnyEditBlock();
            }
            # Check block state against master, thus 'false'.
            $status->setResult( false, self::AS_BLOCKED_PAGE_FOR_USER );
            return $status;
        }

        $this->contentLength = strlen( $this->textbox1 );
        if ( $this->contentLength > $wgMaxArticleSize * 1024 ) {
            // Error will be displayed by showEditForm()
            $this->tooBig = true;
            $status->setResult( false, self::AS_CONTENT_TOO_BIG );
            return $status;
        }

        if ( !$wgUser->isAllowed( 'edit' ) ) {
            if ( $wgUser->isAnon() ) {
                $status->setResult( false, self::AS_READ_ONLY_PAGE_ANON );
                return $status;
            } else {
                $status->fatal( 'readonlytext' );
                $status->value = self::AS_READ_ONLY_PAGE_LOGGED;
                return $status;
            }
        }

        $changingContentModel = false;
        if ( $this->contentModel !== $this->mTitle->getContentModel() ) {
            if ( !$wgContentHandlerUseDB ) {
                $status->fatal( 'editpage-cannot-use-custom-model' );
                $status->value = self::AS_CANNOT_USE_CUSTOM_MODEL;
                return $status;
            } elseif ( !$wgUser->isAllowed( 'editcontentmodel' ) ) {
                $status->setResult( false, self::AS_NO_CHANGE_CONTENT_MODEL );
                return $status;

            }
            $changingContentModel = true;
            $oldContentModel = $this->mTitle->getContentModel();
        }

        if ( $this->changeTags ) {
            $changeTagsStatus = ChangeTags::canAddTagsAccompanyingChange(
                $this->changeTags, $wgUser );
            if ( !$changeTagsStatus->isOK() ) {
                $changeTagsStatus->value = self::AS_CHANGE_TAG_ERROR;
                return $changeTagsStatus;
            }
        }

        if ( wfReadOnly() ) {
            $status->fatal( 'readonlytext' );
            $status->value = self::AS_READ_ONLY_PAGE;
            return $status;
        }
        if ( $wgUser->pingLimiter() || $wgUser->pingLimiter( 'linkpurge', 0 ) ) {
            $status->fatal( 'actionthrottledtext' );
            $status->value = self::AS_RATE_LIMITED;
            return $status;
        }

        # If the article has been deleted while editing, don't save it without
        # confirmation
        if ( $this->wasDeletedSinceLastEdit() && !$this->recreate ) {
            $status->setResult( false, self::AS_ARTICLE_WAS_DELETED );
            return $status;
        }

        # Load the page data from the master. If anything changes in the meantime,
        # we detect it by using page_latest like a token in a 1 try compare-and-swap.
        $this->page->loadPageData( 'fromdbmaster' );
        $new = !$this->page->exists();

        if ( $new ) {
            // Late check for create permission, just in case *PARANOIA*
            if ( !$this->mTitle->userCan( 'create', $wgUser ) ) {
                $status->fatal( 'nocreatetext' );
                $status->value = self::AS_NO_CREATE_PERMISSION;
                wfDebug( __METHOD__ . ": no create permission\n" );
                return $status;
            }

            // Don't save a new page if it's blank or if it's a MediaWiki:
            // message with content equivalent to default (allow empty pages
            // in this case to disable messages, see bug 50124)
            $defaultMessageText = $this->mTitle->getDefaultMessageText();
            if ( $this->mTitle->getNamespace() === NS_MEDIAWIKI && $defaultMessageText !== false ) {
                $defaultText = $defaultMessageText;
            } else {
                $defaultText = '';
            }

            if ( !$this->allowBlankArticle && $this->textbox1 === $defaultText ) {
                $this->blankArticle = true;
                $status->fatal( 'blankarticle' );
                $status->setResult( false, self::AS_BLANK_ARTICLE );
                return $status;
            }

            if ( !$this->runPostMergeFilters( $textbox_content, $status, $wgUser ) ) {
                return $status;
            }

            $content = $textbox_content;

            $result['sectionanchor'] = '';
            if ( $this->section == 'new' ) {
                if ( $this->sectiontitle !== '' ) {
                    // Insert the section title above the content.
                    $content = $content->addSectionHeader( $this->sectiontitle );
                } elseif ( $this->summary !== '' ) {
                    // Insert the section title above the content.
                    $content = $content->addSectionHeader( $this->summary );
                }
                $this->summary = $this->newSectionSummary( $result['sectionanchor'] );
            }

            $status->value = self::AS_SUCCESS_NEW_ARTICLE;

        } else { # not $new

            # Article exists. Check for edit conflict.

            $this->page->clear(); # Force reload of dates, etc.
            $timestamp = $this->page->getTimestamp();
            $latest = $this->page->getLatest();

            wfDebug( "timestamp: {$timestamp}, edittime: {$this->edittime}\n" );

            // Check editRevId if set, which handles same-second timestamp collisions
            if ( $timestamp != $this->edittime
                || ( $this->editRevId !== null && $this->editRevId != $latest )
            ) {
                $this->isConflict = true;
                if ( $this->section == 'new' ) {
                    if ( $this->page->getUserText() == $wgUser->getName() &&
                        $this->page->getComment() == $this->newSectionSummary()
                    ) {
                        // Probably a duplicate submission of a new comment.
                        // This can happen when CDN resends a request after
                        // a timeout but the first one actually went through.
                        wfDebug( __METHOD__
                            . ": duplicate new section submission; trigger edit conflict!\n" );
                    } else {
                        // New comment; suppress conflict.
                        $this->isConflict = false;
                        wfDebug( __METHOD__ . ": conflict suppressed; new section\n" );
                    }
                } elseif ( $this->section == ''
                    && Revision::userWasLastToEdit(
                        DB_MASTER, $this->mTitle->getArticleID(),
                        $wgUser->getId(), $this->edittime
                    )
                ) {
                    # Suppress edit conflict with self, except for section edits where merging is required.
                    wfDebug( __METHOD__ . ": Suppressing edit conflict, same user.\n" );
                    $this->isConflict = false;
                }
            }

            // If sectiontitle is set, use it, otherwise use the summary as the section title.
            if ( $this->sectiontitle !== '' ) {
                $sectionTitle = $this->sectiontitle;
            } else {
                $sectionTitle = $this->summary;
            }

            $content = null;

            if ( $this->isConflict ) {
                wfDebug( __METHOD__
                    . ": conflict! getting section '{$this->section}' for time '{$this->edittime}'"
                    . " (id '{$this->editRevId}') (article time '{$timestamp}')\n" );
                // @TODO: replaceSectionAtRev() with base ID (not prior current) for ?oldid=X case
                // ...or disable section editing for non-current revisions (not exposed anyway).
                if ( $this->editRevId !== null ) {
                    $content = $this->page->replaceSectionAtRev(
                        $this->section,
                        $textbox_content,
                        $sectionTitle,
                        $this->editRevId
                    );
                } else {
                    $content = $this->page->replaceSectionContent(
                        $this->section,
                        $textbox_content,
                        $sectionTitle,
                        $this->edittime
                    );
                }
            } else {
                wfDebug( __METHOD__ . ": getting section '{$this->section}'\n" );
                $content = $this->page->replaceSectionContent(
                    $this->section,
                    $textbox_content,
                    $sectionTitle
                );
            }

            if ( is_null( $content ) ) {
                wfDebug( __METHOD__ . ": activating conflict; section replace failed.\n" );
                $this->isConflict = true;
                $content = $textbox_content; // do not try to merge here!
            } elseif ( $this->isConflict ) {
                # Attempt merge
                if ( $this->mergeChangesIntoContent( $content ) ) {
                    // Successful merge! Maybe we should tell the user the good news?
                    $this->isConflict = false;
                    wfDebug( __METHOD__ . ": Suppressing edit conflict, successful merge.\n" );
                } else {
                    $this->section = '';
                    $this->textbox1 = ContentHandler::getContentText( $content );
                    wfDebug( __METHOD__ . ": Keeping edit conflict, failed merge.\n" );
                }
            }

            if ( $this->isConflict ) {
                $status->setResult( false, self::AS_CONFLICT_DETECTED );
                return $status;
            }

            if ( !$this->runPostMergeFilters( $content, $status, $wgUser ) ) {
                return $status;
            }

            if ( $this->section == 'new' ) {
                // Handle the user preference to force summaries here
                if ( !$this->allowBlankSummary && trim( $this->summary ) == '' ) {
                    $this->missingSummary = true;
                    $status->fatal( 'missingsummary' ); // or 'missingcommentheader' if $section == 'new'. Blegh
                    $status->value = self::AS_SUMMARY_NEEDED;
                    return $status;
                }

                // Do not allow the user to post an empty comment
                if ( $this->textbox1 == '' ) {
                    $this->missingComment = true;
                    $status->fatal( 'missingcommenttext' );
                    $status->value = self::AS_TEXTBOX_EMPTY;
                    return $status;
                }
            } elseif ( !$this->allowBlankSummary
                && !$content->equals( $this->getOriginalContent( $wgUser ) )
                && !$content->isRedirect()
                && md5( $this->summary ) == $this->autoSumm
            ) {
                $this->missingSummary = true;
                $status->fatal( 'missingsummary' );
                $status->value = self::AS_SUMMARY_NEEDED;
                return $status;
            }

            # All's well
            $sectionanchor = '';
            if ( $this->section == 'new' ) {
                $this->summary = $this->newSectionSummary( $sectionanchor );
            } elseif ( $this->section != '' ) {
                # Try to get a section anchor from the section source, redirect
                # to edited section if header found.
                # XXX: Might be better to integrate this into Article::replaceSectionAtRev
                # for duplicate heading checking and maybe parsing.
                $hasmatch = preg_match( "/^ *([=]{1,6})(.*?)(\\1) *\\n/i", $this->textbox1, $matches );
                # We can't deal with anchors, includes, html etc in the header for now,
                # headline would need to be parsed to improve this.
                if ( $hasmatch && strlen( $matches[2] ) > 0 ) {
                    $sectionanchor = $wgParser->guessLegacySectionNameFromWikiText( $matches[2] );
                }
            }
            $result['sectionanchor'] = $sectionanchor;

            // Save errors may fall down to the edit form, but we've now
            // merged the section into full text. Clear the section field
            // so that later submission of conflict forms won't try to
            // replace that into a duplicated mess.
            $this->textbox1 = $this->toEditText( $content );
            $this->section = '';

            $status->value = self::AS_SUCCESS_UPDATE;
        }

        if ( !$this->allowSelfRedirect
            && $content->isRedirect()
            && $content->getRedirectTarget()->equals( $this->getTitle() )
        ) {
            // If the page already redirects to itself, don't warn.
            $currentTarget = $this->getCurrentContent()->getRedirectTarget();
            if ( !$currentTarget || !$currentTarget->equals( $this->getTitle() ) ) {
                $this->selfRedirect = true;
                $status->fatal( 'selfredirect' );
                $status->value = self::AS_SELF_REDIRECT;
                return $status;
            }
        }

        // Check for length errors again now that the section is merged in
        $this->contentLength = strlen( $this->toEditText( $content ) );
        if ( $this->contentLength > $wgMaxArticleSize * 1024 ) {
            $this->tooBig = true;
            $status->setResult( false, self::AS_MAX_ARTICLE_SIZE_EXCEEDED );
            return $status;
        }

        $flags = EDIT_AUTOSUMMARY |
            ( $new ? EDIT_NEW : EDIT_UPDATE ) |
            ( ( $this->minoredit && !$this->isNew ) ? EDIT_MINOR : 0 ) |
            ( $bot ? EDIT_FORCE_BOT : 0 );

        $doEditStatus = $this->page->doEditContent(
            $content,
            $this->summary,
            $flags,
            false,
            $wgUser,
            $content->getDefaultFormat(),
            $this->changeTags
        );

        if ( !$doEditStatus->isOK() ) {
            // Failure from doEdit()
            // Show the edit conflict page for certain recognized errors from doEdit(),
            // but don't show it for errors from extension hooks
            $errors = $doEditStatus->getErrorsArray();
            if ( in_array( $errors[0][0],
                    [ 'edit-gone-missing', 'edit-conflict', 'edit-already-exists' ] )
            ) {
                $this->isConflict = true;
                // Destroys data doEdit() put in $status->value but who cares
                $doEditStatus->value = self::AS_END;
            }
            return $doEditStatus;
        }

        $result['nullEdit'] = $doEditStatus->hasMessage( 'edit-no-change' );
        if ( $result['nullEdit'] ) {
            // We don't know if it was a null edit until now, so increment here
            $wgUser->pingLimiter( 'linkpurge' );
        }
        $result['redirect'] = $content->isRedirect();

        $this->updateWatchlist();

        // If the content model changed, add a log entry
        if ( $changingContentModel ) {
            $this->addContentModelChangeLogEntry(
                $wgUser,
                $new ? false : $oldContentModel,
                $this->contentModel,
                $this->summary
            );
        }

        return $status;
    }

    protected function addContentModelChangeLogEntry( User $user, $oldModel, $newModel, $reason ) {
        $new = $oldModel === false;
        $log = new ManualLogEntry( 'contentmodel', $new ? 'new' : 'change' );
        $log->setPerformer( $user );
        $log->setTarget( $this->mTitle );
        $log->setComment( $reason );
        $log->setParameters( [
            '4::oldmodel' => $oldModel,
            '5::newmodel' => $newModel
        ] );
        $logid = $log->insert();
        $log->publish( $logid );
    }

    protected function updateWatchlist() {
        global $wgUser;

        if ( !$wgUser->isLoggedIn() ) {
            return;
        }

        $user = $wgUser;
        $title = $this->mTitle;
        $watch = $this->watchthis;
        // Do this in its own transaction to reduce contention...
        DeferredUpdates::addCallableUpdate( function () use ( $user, $title, $watch ) {
            if ( $watch == $user->isWatched( $title, User::IGNORE_USER_RIGHTS ) ) {
                return; // nothing to change
            }
            WatchAction::doWatchOrUnwatch( $watch, $title, $user );
        } );
    }

    private function mergeChangesIntoContent( &$editContent ) {

        $db = wfGetDB( DB_MASTER );

        // This is the revision the editor started from
        $baseRevision = $this->getBaseRevision();
        $baseContent = $baseRevision ? $baseRevision->getContent() : null;

        if ( is_null( $baseContent ) ) {
            return false;
        }

        // The current state, we want to merge updates into it
        $currentRevision = Revision::loadFromTitle( $db, $this->mTitle );
        $currentContent = $currentRevision ? $currentRevision->getContent() : null;

        if ( is_null( $currentContent ) ) {
            return false;
        }

        $handler = ContentHandler::getForModelID( $baseContent->getModel() );

        $result = $handler->merge3( $baseContent, $editContent, $currentContent );

        if ( $result ) {
            $editContent = $result;
            // Update parentRevId to what we just merged.
            $this->parentRevId = $currentRevision->getId();
            return true;
        }

        return false;
    }

    function getBaseRevision() {
        if ( !$this->mBaseRevision ) {
            $db = wfGetDB( DB_MASTER );
            $this->mBaseRevision = $this->editRevId
                ? Revision::newFromId( $this->editRevId, Revision::READ_LATEST )
                : Revision::loadFromTimestamp( $db, $this->mTitle, $this->edittime );
        }
        return $this->mBaseRevision;
    }

    public static function matchSpamRegex( $text ) {
        global $wgSpamRegex;
        // For back compatibility, $wgSpamRegex may be a single string or an array of regexes.
        $regexes = (array)$wgSpamRegex;
        return self::matchSpamRegexInternal( $text, $regexes );
    }

    public static function matchSummarySpamRegex( $text ) {
        global $wgSummarySpamRegex;
        $regexes = (array)$wgSummarySpamRegex;
        return self::matchSpamRegexInternal( $text, $regexes );
    }

    protected static function matchSpamRegexInternal( $text, $regexes ) {
        foreach ( $regexes as $regex ) {
            $matches = [];
            if ( preg_match( $regex, $text, $matches ) ) {
                return $matches[0];
            }
        }
        return false;
    }

    function setHeaders() {
        global $wgOut, $wgUser, $wgAjaxEditStash;

        $wgOut->addModules( 'mediawiki.action.edit' );
        $wgOut->addModuleStyles( 'mediawiki.action.edit.styles' );

        if ( $wgUser->getOption( 'showtoolbar' ) ) {
            // The addition of default buttons is handled by getEditToolbar() which
            // has its own dependency on this module. The call here ensures the module
            // is loaded in time (it has position "top") for other modules to register
            // buttons (e.g. extensions, gadgets, user scripts).
            $wgOut->addModules( 'mediawiki.toolbar' );
        }

        if ( $wgUser->getOption( 'uselivepreview' ) ) {
            $wgOut->addModules( 'mediawiki.action.edit.preview' );
        }

        if ( $wgUser->getOption( 'useeditwarning' ) ) {
            $wgOut->addModules( 'mediawiki.action.edit.editWarning' );
        }

        # Enabled article-related sidebar, toplinks, etc.
        $wgOut->setArticleRelated( true );

        $contextTitle = $this->getContextTitle();
        if ( $this->isConflict ) {
            $msg = 'editconflict';
        } elseif ( $contextTitle->exists() && $this->section != '' ) {
            $msg = $this->section == 'new' ? 'editingcomment' : 'editingsection';
        } else {
            $msg = $contextTitle->exists()
                || ( $contextTitle->getNamespace() == NS_MEDIAWIKI
                    && $contextTitle->getDefaultMessageText() !== false
                )
                ? 'editing'
                : 'creating';
        }

        # Use the title defined by DISPLAYTITLE magic word when present
        # NOTE: getDisplayTitle() returns HTML while getPrefixedText() returns plain text.
        #       setPageTitle() treats the input as wikitext, which should be safe in either case.
        $displayTitle = isset( $this->mParserOutput ) ? $this->mParserOutput->getDisplayTitle() : false;
        if ( $displayTitle === false ) {
            $displayTitle = $contextTitle->getPrefixedText();
        }
        $wgOut->setPageTitle( wfMessage( $msg, $displayTitle ) );
        # Transmit the name of the message to JavaScript for live preview
        # Keep Resources.php/mediawiki.action.edit.preview in sync with the possible keys
        $wgOut->addJsConfigVars( [
            'wgEditMessage' => $msg,
            'wgAjaxEditStash' => $wgAjaxEditStash,
        ] );
    }

    protected function showIntro() {
        global $wgOut, $wgUser;
        if ( $this->suppressIntro ) {
            return;
        }

        $namespace = $this->mTitle->getNamespace();

        if ( $namespace == NS_MEDIAWIKI ) {
            # Show a warning if editing an interface message
            $wgOut->wrapWikiMsg( "<div class='mw-editinginterface'>\n$1\n</div>", 'editinginterface' );
            # If this is a default message (but not css or js),
            # show a hint that it is translatable on translatewiki.net
            if ( !$this->mTitle->hasContentModel( CONTENT_MODEL_CSS )
                && !$this->mTitle->hasContentModel( CONTENT_MODEL_JAVASCRIPT )
            ) {
                $defaultMessageText = $this->mTitle->getDefaultMessageText();
                if ( $defaultMessageText !== false ) {
                    $wgOut->wrapWikiMsg( "<div class='mw-translateinterface'>\n$1\n</div>",
                        'translateinterface' );
                }
            }
        } elseif ( $namespace == NS_FILE ) {
            # Show a hint to shared repo
            $file = wfFindFile( $this->mTitle );
            if ( $file && !$file->isLocal() ) {
                $descUrl = $file->getDescriptionUrl();
                # there must be a description url to show a hint to shared repo
                if ( $descUrl ) {
                    if ( !$this->mTitle->exists() ) {
                        $wgOut->wrapWikiMsg( "<div class=\"mw-sharedupload-desc-create\">\n$1\n</div>", [
                                    'sharedupload-desc-create', $file->getRepo()->getDisplayName(), $descUrl
                        ] );
                    } else {
                        $wgOut->wrapWikiMsg( "<div class=\"mw-sharedupload-desc-edit\">\n$1\n</div>", [
                                    'sharedupload-desc-edit', $file->getRepo()->getDisplayName(), $descUrl
                        ] );
                    }
                }
            }
        }

        # Show a warning message when someone creates/edits a user (talk) page but the user does not exist
        # Show log extract when the user is currently blocked
        if ( $namespace == NS_USER || $namespace == NS_USER_TALK ) {
            $username = explode( '/', $this->mTitle->getText(), 2 )[0];
            $user = User::newFromName( $username, false /* allow IP users*/ );
            $ip = User::isIP( $username );
            $block = Block::newFromTarget( $user, $user );
            if ( !( $user && $user->isLoggedIn() ) && !$ip ) { # User does not exist
                $wgOut->wrapWikiMsg( "<div class=\"mw-userpage-userdoesnotexist error\">\n$1\n</div>",
                    [ 'userpage-userdoesnotexist', wfEscapeWikiText( $username ) ] );
            } elseif ( !is_null( $block ) && $block->getType() != Block::TYPE_AUTO ) {
                # Show log extract if the user is currently blocked
                LogEventsList::showLogExtract(
                    $wgOut,
                    'block',
                    MWNamespace::getCanonicalName( NS_USER ) . ':' . $block->getTarget(),
                    '',
                    [
                        'lim' => 1,
                        'showIfEmpty' => false,
                        'msgKey' => [
                            'blocked-notice-logextract',
                            $user->getName() # Support GENDER in notice
                        ]
                    ]
                );
            }
        }
        # Try to add a custom edit intro, or use the standard one if this is not possible.
        if ( !$this->showCustomIntro() && !$this->mTitle->exists() ) {
            $helpLink = wfExpandUrl( Skin::makeInternalOrExternalUrl(
                wfMessage( 'helppage' )->inContentLanguage()->text()
            ) );
            if ( $wgUser->isLoggedIn() ) {
                $wgOut->wrapWikiMsg(
                    // Suppress the external link icon, consider the help url an internal one
                    "<div class=\"mw-newarticletext plainlinks\">\n$1\n</div>",
                    [
                        'newarticletext',
                        $helpLink
                    ]
                );
            } else {
                $wgOut->wrapWikiMsg(
                    // Suppress the external link icon, consider the help url an internal one
                    "<div class=\"mw-newarticletextanon plainlinks\">\n$1\n</div>",
                    [
                        'newarticletextanon',
                        $helpLink
                    ]
                );
            }
        }
        # Give a notice if the user is editing a deleted/moved page...
        if ( !$this->mTitle->exists() ) {
            LogEventsList::showLogExtract( $wgOut, [ 'delete', 'move' ], $this->mTitle,
                '',
                [
                    'lim' => 10,
                    'conds' => [ "log_action != 'revision'" ],
                    'showIfEmpty' => false,
                    'msgKey' => [ 'recreate-moveddeleted-warn' ]
                ]
            );
        }
    }

    protected function showCustomIntro() {
        if ( $this->editintro ) {
            $title = Title::newFromText( $this->editintro );
            if ( $title instanceof Title && $title->exists() && $title->userCan( 'read' ) ) {
                global $wgOut;
                // Added using template syntax, to take <noinclude>'s into account.
                $wgOut->addWikiTextTitleTidy(
                    '<div class="mw-editintro">{{:' . $title->getFullText() . '}}</div>',
                    $this->mTitle
                );
                return true;
            }
        }
        return false;
    }

    protected function toEditText( $content ) {
        if ( $content === null || $content === false || is_string( $content ) ) {
            return $content;
        }

        if ( !$this->isSupportedContentModel( $content->getModel() ) ) {
            throw new MWException( 'This content model is not supported: '
                . ContentHandler::getLocalizedName( $content->getModel() ) );
        }

        return $content->serialize( $this->contentFormat );
    }

    protected function toEditContent( $text ) {
        if ( $text === false || $text === null ) {
            return $text;
        }

        $content = ContentHandler::makeContent( $text, $this->getTitle(),
            $this->contentModel, $this->contentFormat );

        if ( !$this->isSupportedContentModel( $content->getModel() ) ) {
            throw new MWException( 'This content model is not supported: '
                . ContentHandler::getLocalizedName( $content->getModel() ) );
        }

        return $content;
    }

    function showEditForm( $formCallback = null ) {
        global $wgOut, $wgUser;

        # need to parse the preview early so that we know which templates are used,
        # otherwise users with "show preview after edit box" will get a blank list
        # we parse this near the beginning so that setHeaders can do the title
        # setting work instead of leaving it in getPreviewText
        $previewOutput = '';
        if ( $this->formtype == 'preview' ) {
            $previewOutput = $this->getPreviewText();
        }

        Hooks::run( 'EditPage::showEditForm:initial', [ &$this, &$wgOut ] );

        $this->setHeaders();

        if ( $this->showHeader() === false ) {
            return;
        }

        $wgOut->addHTML( $this->editFormPageTop );

        if ( $wgUser->getOption( 'previewontop' ) ) {
            $this->displayPreviewArea( $previewOutput, true );
        }

        $wgOut->addHTML( $this->editFormTextTop );

        $showToolbar = true;
        if ( $this->wasDeletedSinceLastEdit() ) {
            if ( $this->formtype == 'save' ) {
                // Hide the toolbar and edit area, user can click preview to get it back
                // Add an confirmation checkbox and explanation.
                $showToolbar = false;
            } else {
                $wgOut->wrapWikiMsg( "<div class='error mw-deleted-while-editing'>\n$1\n</div>",
                    'deletedwhileediting' );
            }
        }

        // @todo add EditForm plugin interface and use it here!
        //       search for textarea1 and textares2, and allow EditForm to override all uses.
        $wgOut->addHTML( Html::openElement(
            'form',
            [
                'id' => self::EDITFORM_ID,
                'name' => self::EDITFORM_ID,
                'method' => 'post',
                'action' => $this->getActionURL( $this->getContextTitle() ),
                'enctype' => 'multipart/form-data'
            ]
        ) );

        if ( is_callable( $formCallback ) ) {
            wfWarn( 'The $formCallback parameter to ' . __METHOD__ . 'is deprecated' );
            call_user_func_array( $formCallback, [ &$wgOut ] );
        }

        // Add an empty field to trip up spambots
        $wgOut->addHTML(
            Xml::openElement( 'div', [ 'id' => 'antispam-container', 'style' => 'display: none;' ] )
            . Html::rawElement(
                'label',
                [ 'for' => 'wpAntispam' ],
                wfMessage( 'simpleantispam-label' )->parse()
            )
            . Xml::element(
                'input',
                [
                    'type' => 'text',
                    'name' => 'wpAntispam',
                    'id' => 'wpAntispam',
                    'value' => ''
                ]
            )
            . Xml::closeElement( 'div' )
        );

        Hooks::run( 'EditPage::showEditForm:fields', [ &$this, &$wgOut ] );

        // Put these up at the top to ensure they aren't lost on early form submission
        $this->showFormBeforeText();

        if ( $this->wasDeletedSinceLastEdit() && 'save' == $this->formtype ) {
            $username = $this->lastDelete->user_name;
            $comment = $this->lastDelete->log_comment;

            // It is better to not parse the comment at all than to have templates expanded in the middle
            // TODO: can the checkLabel be moved outside of the div so that wrapWikiMsg could be used?
            $key = $comment === ''
                ? 'confirmrecreate-noreason'
                : 'confirmrecreate';
            $wgOut->addHTML(
                '<div class="mw-confirm-recreate">' .
                    wfMessage( $key, $username, "<nowiki>$comment</nowiki>" )->parse() .
                Xml::checkLabel( wfMessage( 'recreate' )->text(), 'wpRecreate', 'wpRecreate', false,
                    [ 'title' => Linker::titleAttrib( 'recreate' ), 'tabindex' => 1, 'id' => 'wpRecreate' ]
                ) .
                '</div>'
            );
        }

        # When the summary is hidden, also hide them on preview/show changes
        if ( $this->nosummary ) {
            $wgOut->addHTML( Html::hidden( 'nosummary', true ) );
        }

        # If a blank edit summary was previously provided, and the appropriate
        # user preference is active, pass a hidden tag as wpIgnoreBlankSummary. This will stop the
        # user being bounced back more than once in the event that a summary
        # is not required.
        # ####
        # For a bit more sophisticated detection of blank summaries, hash the
        # automatic one and pass that in the hidden field wpAutoSummary.
        if ( $this->missingSummary || ( $this->section == 'new' && $this->nosummary ) ) {
            $wgOut->addHTML( Html::hidden( 'wpIgnoreBlankSummary', true ) );
        }

        if ( $this->undidRev ) {
            $wgOut->addHTML( Html::hidden( 'wpUndidRevision', $this->undidRev ) );
        }

        if ( $this->selfRedirect ) {
            $wgOut->addHTML( Html::hidden( 'wpIgnoreSelfRedirect', true ) );
        }

        if ( $this->hasPresetSummary ) {
            // If a summary has been preset using &summary= we don't want to prompt for
            // a different summary. Only prompt for a summary if the summary is blanked.
            // (Bug 17416)
            $this->autoSumm = md5( '' );
        }

        $autosumm = $this->autoSumm ? $this->autoSumm : md5( $this->summary );
        $wgOut->addHTML( Html::hidden( 'wpAutoSummary', $autosumm ) );

        $wgOut->addHTML( Html::hidden( 'oldid', $this->oldid ) );
        $wgOut->addHTML( Html::hidden( 'parentRevId', $this->getParentRevId() ) );

        $wgOut->addHTML( Html::hidden( 'format', $this->contentFormat ) );
        $wgOut->addHTML( Html::hidden( 'model', $this->contentModel ) );

        if ( $this->section == 'new' ) {
            $this->showSummaryInput( true, $this->summary );
            $wgOut->addHTML( $this->getSummaryPreview( true, $this->summary ) );
        }

        $wgOut->addHTML( $this->editFormTextBeforeContent );

        if ( !$this->isCssJsSubpage && $showToolbar && $wgUser->getOption( 'showtoolbar' ) ) {
            $wgOut->addHTML( EditPage::getEditToolbar( $this->mTitle ) );
        }

        if ( $this->blankArticle ) {
            $wgOut->addHTML( Html::hidden( 'wpIgnoreBlankArticle', true ) );
        }

        if ( $this->isConflict ) {
            // In an edit conflict bypass the overridable content form method
            // and fallback to the raw wpTextbox1 since editconflicts can't be
            // resolved between page source edits and custom ui edits using the
            // custom edit ui.
            $this->textbox2 = $this->textbox1;

            $content = $this->getCurrentContent();
            $this->textbox1 = $this->toEditText( $content );

            $this->showTextbox1();
        } else {
            $this->showContentForm();
        }

        $wgOut->addHTML( $this->editFormTextAfterContent );

        $this->showStandardInputs();

        $this->showFormAfterText();

        $this->showTosSummary();

        $this->showEditTools();

        $wgOut->addHTML( $this->editFormTextAfterTools . "\n" );

        $wgOut->addHTML( Html::rawElement( 'div', [ 'class' => 'templatesUsed' ],
            Linker::formatTemplates( $this->getTemplates(), $this->preview, $this->section != '' ) ) );

        $wgOut->addHTML( Html::rawElement( 'div', [ 'class' => 'hiddencats' ],
            Linker::formatHiddenCategories( $this->page->getHiddenCategories() ) ) );

        $wgOut->addHTML( Html::rawElement( 'div', [ 'class' => 'limitreport' ],
            self::getPreviewLimitReport( $this->mParserOutput ) ) );

        $wgOut->addModules( 'mediawiki.action.edit.collapsibleFooter' );

        if ( $this->isConflict ) {
            try {
                $this->showConflict();
            } catch ( MWContentSerializationException $ex ) {
                // this can't really happen, but be nice if it does.
                $msg = wfMessage(
                    'content-failed-to-parse',
                    $this->contentModel,
                    $this->contentFormat,
                    $ex->getMessage()
                );
                $wgOut->addWikiText( '<div class="error">' . $msg->text() . '</div>' );
            }
        }

        // Set a hidden field so JS knows what edit form mode we are in
        if ( $this->isConflict ) {
            $mode = 'conflict';
        } elseif ( $this->preview ) {
            $mode = 'preview';
        } elseif ( $this->diff ) {
            $mode = 'diff';
        } else {
            $mode = 'text';
        }
        $wgOut->addHTML( Html::hidden( 'mode', $mode, [ 'id' => 'mw-edit-mode' ] ) );

        // Marker for detecting truncated form data.  This must be the last
        // parameter sent in order to be of use, so do not move me.
        $wgOut->addHTML( Html::hidden( 'wpUltimateParam', true ) );
        $wgOut->addHTML( $this->editFormTextBottom . "\n</form>\n" );

        if ( !$wgUser->getOption( 'previewontop' ) ) {
            $this->displayPreviewArea( $previewOutput, false );
        }

    }

    public static function extractSectionTitle( $text ) {
        preg_match( "/^(=+)(.+)\\1\\s*(\n|$)/i", $text, $matches );
        if ( !empty( $matches[2] ) ) {
            global $wgParser;
            return $wgParser->stripSectionName( trim( $matches[2] ) );
        } else {
            return false;
        }
    }

    protected function showHeader() {
        global $wgOut, $wgUser, $wgMaxArticleSize, $wgLang;
        global $wgAllowUserCss, $wgAllowUserJs;

        if ( $this->mTitle->isTalkPage() ) {
            $wgOut->addWikiMsg( 'talkpagetext' );
        }

        // Add edit notices
        $editNotices = $this->mTitle->getEditNotices( $this->oldid );
        if ( count( $editNotices ) ) {
            $wgOut->addHTML( implode( "\n", $editNotices ) );
        } else {
            $msg = wfMessage( 'editnotice-notext' );
            if ( !$msg->isDisabled() ) {
                $wgOut->addHTML(
                    '<div class="mw-editnotice-notext">'
                    . $msg->parseAsBlock()
                    . '</div>'
                );
            }
        }

        if ( $this->isConflict ) {
            $wgOut->wrapWikiMsg( "<div class='mw-explainconflict'>\n$1\n</div>", 'explainconflict' );
            $this->editRevId = $this->page->getLatest();
        } else {
            if ( $this->section != '' && !$this->isSectionEditSupported() ) {
                // We use $this->section to much before this and getVal('wgSection') directly in other places
                // at this point we can't reset $this->section to '' to fallback to non-section editing.
                // Someone is welcome to try refactoring though
                $wgOut->showErrorPage( 'sectioneditnotsupported-title', 'sectioneditnotsupported-text' );
                return false;
            }

            if ( $this->section != '' && $this->section != 'new' ) {
                if ( !$this->summary && !$this->preview && !$this->diff ) {
                    $sectionTitle = self::extractSectionTitle( $this->textbox1 ); // FIXME: use Content object
                    if ( $sectionTitle !== false ) {
                        $this->summary = "/* $sectionTitle */ ";
                    }
                }
            }

            if ( $this->missingComment ) {
                $wgOut->wrapWikiMsg( "<div id='mw-missingcommenttext'>\n$1\n</div>", 'missingcommenttext' );
            }

            if ( $this->missingSummary && $this->section != 'new' ) {
                $wgOut->wrapWikiMsg( "<div id='mw-missingsummary'>\n$1\n</div>", 'missingsummary' );
            }

            if ( $this->missingSummary && $this->section == 'new' ) {
                $wgOut->wrapWikiMsg( "<div id='mw-missingcommentheader'>\n$1\n</div>", 'missingcommentheader' );
            }

            if ( $this->blankArticle ) {
                $wgOut->wrapWikiMsg( "<div id='mw-blankarticle'>\n$1\n</div>", 'blankarticle' );
            }

            if ( $this->selfRedirect ) {
                $wgOut->wrapWikiMsg( "<div id='mw-selfredirect'>\n$1\n</div>", 'selfredirect' );
            }

            if ( $this->hookError !== '' ) {
                $wgOut->addWikiText( $this->hookError );
            }

            if ( !$this->checkUnicodeCompliantBrowser() ) {
                $wgOut->addWikiMsg( 'nonunicodebrowser' );
            }

            if ( $this->section != 'new' ) {
                $revision = $this->mArticle->getRevisionFetched();
                if ( $revision ) {
                    // Let sysop know that this will make private content public if saved

                    if ( !$revision->userCan( Revision::DELETED_TEXT, $wgUser ) ) {
                        $wgOut->wrapWikiMsg(
                            "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
                            'rev-deleted-text-permission'
                        );
                    } elseif ( $revision->isDeleted( Revision::DELETED_TEXT ) ) {
                        $wgOut->wrapWikiMsg(
                            "<div class='mw-warning plainlinks'>\n$1\n</div>\n",
                            'rev-deleted-text-view'
                        );
                    }

                    if ( !$revision->isCurrent() ) {
                        $this->mArticle->setOldSubtitle( $revision->getId() );
                        $wgOut->addWikiMsg( 'editingold' );
                    }
                } elseif ( $this->mTitle->exists() ) {
                    // Something went wrong

                    $wgOut->wrapWikiMsg( "<div class='errorbox'>\n$1\n</div>\n",
                        [ 'missing-revision', $this->oldid ] );
                }
            }
        }

        if ( wfReadOnly() ) {
            $wgOut->wrapWikiMsg(
                "<div id=\"mw-read-only-warning\">\n$1\n</div>",
                [ 'readonlywarning', wfReadOnlyReason() ]
            );
        } elseif ( $wgUser->isAnon() ) {
            if ( $this->formtype != 'preview' ) {
                $wgOut->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 {
                $wgOut->wrapWikiMsg( "<div id=\"mw-anon-preview-warning\" class=\"warningbox\">\n$1</div>",
                    'anonpreviewwarning'
                );
            }
        } else {
            if ( $this->isCssJsSubpage ) {
                # Check the skin exists
                if ( $this->isWrongCaseCssJsPage ) {
                    $wgOut->wrapWikiMsg(
                        "<div class='error' id='mw-userinvalidcssjstitle'>\n$1\n</div>",
                        [ 'userinvalidcssjstitle', $this->mTitle->getSkinFromCssJsSubpage() ]
                    );
                }
                if ( $this->getTitle()->isSubpageOf( $wgUser->getUserPage() ) ) {
                    if ( $this->formtype !== 'preview' ) {
                        if ( $this->isCssSubpage && $wgAllowUserCss ) {
                            $wgOut->wrapWikiMsg(
                                "<div id='mw-usercssyoucanpreview'>\n$1\n</div>",
                                [ 'usercssyoucanpreview' ]
                            );
                        }

                        if ( $this->isJsSubpage && $wgAllowUserJs ) {
                            $wgOut->wrapWikiMsg(
                                "<div id='mw-userjsyoucanpreview'>\n$1\n</div>",
                                [ 'userjsyoucanpreview' ]
                            );
                        }
                    }
                }
            }
        }

        if ( $this->mTitle->isProtected( 'edit' ) &&
            MWNamespace::getRestrictionLevels( $this->mTitle->getNamespace() ) !== [ '' ]
        ) {
            # Is the title semi-protected?
            if ( $this->mTitle->isSemiProtected() ) {
                $noticeMsg = 'semiprotectedpagewarning';
            } else {
                # Then it must be protected based on static groups (regular)
                $noticeMsg = 'protectedpagewarning';
            }
            LogEventsList::showLogExtract( $wgOut, 'protect', $this->mTitle, '',
                [ 'lim' => 1, 'msgKey' => [ $noticeMsg ] ] );
        }
        if ( $this->mTitle->isCascadeProtected() ) {
            # Is this page under cascading protection from some source pages?

            list( $cascadeSources, /* $restrictions */ ) = $this->mTitle->getCascadeProtectionSources();
            $notice = "<div class='mw-cascadeprotectedwarning'>\n$1\n";
            $cascadeSourcesCount = count( $cascadeSources );
            if ( $cascadeSourcesCount > 0 ) {
                # Explain, and list the titles responsible
                foreach ( $cascadeSources as $page ) {
                    $notice .= '* [[:' . $page->getPrefixedText() . "]]\n";
                }
            }
            $notice .= '</div>';
            $wgOut->wrapWikiMsg( $notice, [ 'cascadeprotectedwarning', $cascadeSourcesCount ] );
        }
        if ( !$this->mTitle->exists() && $this->mTitle->getRestrictions( 'create' ) ) {
            LogEventsList::showLogExtract( $wgOut, 'protect', $this->mTitle, '',
                [ 'lim' => 1,
                    'showIfEmpty' => false,
                    'msgKey' => [ 'titleprotectedwarning' ],
                    'wrap' => "<div class=\"mw-titleprotectedwarning\">\n$1</div>" ] );
        }

        if ( $this->contentLength === false ) {
            $this->contentLength = strlen( $this->textbox1 );
        }

        if ( $this->tooBig || $this->contentLength > $wgMaxArticleSize * 1024 ) {
            $wgOut->wrapWikiMsg( "<div class='error' id='mw-edit-longpageerror'>\n$1\n</div>",
                [
                    'longpageerror',
                    $wgLang->formatNum( round( $this->contentLength / 1024, 3 ) ),
                    $wgLang->formatNum( $wgMaxArticleSize )
                ]
            );
        } else {
            if ( !wfMessage( 'longpage-hint' )->isDisabled() ) {
                $wgOut->wrapWikiMsg( "<div id='mw-edit-longpage-hint'>\n$1\n</div>",
                    [
                        'longpage-hint',
                        $wgLang->formatSize( strlen( $this->textbox1 ) ),
                        strlen( $this->textbox1 )
                    ]
                );
            }
        }
        # Add header copyright warning
        $this->showHeaderCopyrightWarning();

        return true;
    }

    function getSummaryInput( $summary = "", $labelText = null,
        $inputAttrs = null, $spanLabelAttrs = null
    ) {
        // Note: the maxlength is overridden in JS to 255 and to make it use UTF-8 bytes, not characters.
        $inputAttrs = ( is_array( $inputAttrs ) ? $inputAttrs : [] ) + [
            'id' => 'wpSummary',
            'maxlength' => '200',
            'tabindex' => '1',
            'size' => 60,
            'spellcheck' => 'true',
        ] + Linker::tooltipAndAccesskeyAttribs( 'summary' );

        $spanLabelAttrs = ( is_array( $spanLabelAttrs ) ? $spanLabelAttrs : [] ) + [
            'class' => $this->missingSummary ? 'mw-summarymissed' : 'mw-summary',
            'id' => "wpSummaryLabel"
        ];

        $label = null;
        if ( $labelText ) {
            $label = Xml::tags(
                'label',
                $inputAttrs['id'] ? [ 'for' => $inputAttrs['id'] ] : null,
                $labelText
            );
            $label = Xml::tags( 'span', $spanLabelAttrs, $label );
        }

        $input = Html::input( 'wpSummary', $summary, 'text', $inputAttrs );

        return [ $label, $input ];
    }

    protected function showSummaryInput( $isSubjectPreview, $summary = "" ) {
        global $wgOut;
        # Add a class if 'missingsummary' is triggered to allow styling of the summary line
        $summaryClass = $this->missingSummary ? 'mw-summarymissed' : 'mw-summary';
        if ( $isSubjectPreview ) {
            if ( $this->nosummary ) {
                return;
            }
        } else {
            if ( !$this->mShowSummaryField ) {
                return;
            }
        }
        $labelText = wfMessage( $isSubjectPreview ? 'subject' : 'summary' )->parse();
        list( $label, $input ) = $this->getSummaryInput(
            $summary,
            $labelText,
            [ 'class' => $summaryClass ],
            []
        );
        $wgOut->addHTML( "{$label} {$input}" );
    }

    protected function getSummaryPreview( $isSubjectPreview, $summary = "" ) {
        // avoid spaces in preview, gets always trimmed on save
        $summary = trim( $summary );
        if ( !$summary || ( !$this->preview && !$this->diff ) ) {
            return "";
        }

        global $wgParser;

        if ( $isSubjectPreview ) {
            $summary = wfMessage( 'newsectionsummary' )->rawParams( $wgParser->stripSectionName( $summary ) )
                ->inContentLanguage()->text();
        }

        $message = $isSubjectPreview ? 'subject-preview' : 'summary-preview';

        $summary = wfMessage( $message )->parse()
            . Linker::commentBlock( $summary, $this->mTitle, $isSubjectPreview );
        return Xml::tags( 'div', [ 'class' => 'mw-summary-preview' ], $summary );
    }

    protected function showFormBeforeText() {
        global $wgOut;
        $section = htmlspecialchars( $this->section );
        $wgOut->addHTML( <<<HTML
<input type='hidden' value="{$section}" name="wpSection"/>
<input type='hidden' value="{$this->starttime}" name="wpStarttime" />
<input type='hidden' value="{$this->edittime}" name="wpEdittime" />
<input type='hidden' value="{$this->editRevId}" name="editRevId" />
<input type='hidden' value="{$this->scrolltop}" name="wpScrolltop" id="wpScrolltop" />

HTML
        );
        if ( !$this->checkUnicodeCompliantBrowser() ) {
            $wgOut->addHTML( Html::hidden( 'safemode', '1' ) );
        }
    }

    protected function showFormAfterText() {
        global $wgOut, $wgUser;
        $wgOut->addHTML( "\n" . Html::hidden( "wpEditToken", $wgUser->getEditToken() ) . "\n" );
    }

    protected function showContentForm() {
        $this->showTextbox1();
    }

    protected function showTextbox1( $customAttribs = null, $textoverride = null ) {
        if ( $this->wasDeletedSinceLastEdit() && $this->formtype == 'save' ) {
            $attribs = [ 'style' => 'display:none;' ];
        } else {
            $classes = []; // Textarea CSS
            if ( $this->mTitle->isProtected( 'edit' ) &&
                MWNamespace::getRestrictionLevels( $this->mTitle->getNamespace() ) !== [ '' ]
            ) {
                # Is the title semi-protected?
                if ( $this->mTitle->isSemiProtected() ) {
                    $classes[] = 'mw-textarea-sprotected';
                } else {
                    # Then it must be protected based on static groups (regular)
                    $classes[] = 'mw-textarea-protected';
                }
                # Is the title cascade-protected?
                if ( $this->mTitle->isCascadeProtected() ) {
                    $classes[] = 'mw-textarea-cprotected';
                }
            }

            $attribs = [ 'tabindex' => 1 ];

            if ( is_array( $customAttribs ) ) {
                $attribs += $customAttribs;
            }

            if ( count( $classes ) ) {
                if ( isset( $attribs['class'] ) ) {
                    $classes[] = $attribs['class'];
                }
                $attribs['class'] = implode( ' ', $classes );
            }
        }

        $this->showTextbox(
            $textoverride !== null ? $textoverride : $this->textbox1,
            'wpTextbox1',
            $attribs
        );
    }

    protected function showTextbox2() {
        $this->showTextbox( $this->textbox2, 'wpTextbox2', [ 'tabindex' => 6, 'readonly' ] );
    }

    protected function showTextbox( $text, $name, $customAttribs = [] ) {
        global $wgOut, $wgUser;

        $wikitext = $this->safeUnicodeOutput( $text );
        if ( strval( $wikitext ) !== '' ) {
            // Ensure there's a newline at the end, otherwise adding lines
            // is awkward.
            // But don't add a newline if the ext is empty, or Firefox in XHTML
            // mode will show an extra newline. A bit annoying.
            $wikitext .= "\n";
        }

        $attribs = $customAttribs + [
            'accesskey' => ',',
            'id' => $name,
            'cols' => $wgUser->getIntOption( 'cols' ),
            'rows' => $wgUser->getIntOption( 'rows' ),
            // Avoid PHP notices when appending preferences
            // (appending allows customAttribs['style'] to still work).
            'style' => ''
        ];

        $pageLang = $this->mTitle->getPageLanguage();
        $attribs['lang'] = $pageLang->getHtmlCode();
        $attribs['dir'] = $pageLang->getDir();

        $wgOut->addHTML( Html::textarea( $name, $wikitext, $attribs ) );
    }

    protected function displayPreviewArea( $previewOutput, $isOnTop = false ) {
        global $wgOut;
        $classes = [];
        if ( $isOnTop ) {
            $classes[] = 'ontop';
        }

        $attribs = [ 'id' => 'wikiPreview', 'class' => implode( ' ', $classes ) ];

        if ( $this->formtype != 'preview' ) {
            $attribs['style'] = 'display: none;';
        }

        $wgOut->addHTML( Xml::openElement( 'div', $attribs ) );

        if ( $this->formtype == 'preview' ) {
            $this->showPreview( $previewOutput );
        } else {
            // Empty content container for LivePreview
            $pageViewLang = $this->mTitle->getPageViewLanguage();
            $attribs = [ 'lang' => $pageViewLang->getHtmlCode(), 'dir' => $pageViewLang->getDir(),
                'class' => 'mw-content-' . $pageViewLang->getDir() ];
            $wgOut->addHTML( Html::rawElement( 'div', $attribs ) );
        }

        $wgOut->addHTML( '</div>' );

        if ( $this->formtype == 'diff' ) {
            try {
                $this->showDiff();
            } catch ( MWContentSerializationException $ex ) {
                $msg = wfMessage(
                    'content-failed-to-parse',
                    $this->contentModel,
                    $this->contentFormat,
                    $ex->getMessage()
                );
                $wgOut->addWikiText( '<div class="error">' . $msg->text() . '</div>' );
            }
        }
    }

    protected function showPreview( $text ) {
        global $wgOut;
        if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
            $this->mArticle->openShowCategory();
        }
        # This hook seems slightly odd here, but makes things more
        # consistent for extensions.
        Hooks::run( 'OutputPageBeforeHTML', [ &$wgOut, &$text ] );
        $wgOut->addHTML( $text );
        if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
            $this->mArticle->closeShowCategory();
        }
    }

    function showDiff() {
        global $wgUser, $wgContLang, $wgOut;

        $oldtitlemsg = 'currentrev';
        # if message does not exist, show diff against the preloaded default
        if ( $this->mTitle->getNamespace() == NS_MEDIAWIKI && !$this->mTitle->exists() ) {
            $oldtext = $this->mTitle->getDefaultMessageText();
            if ( $oldtext !== false ) {
                $oldtitlemsg = 'defaultmessagetext';
                $oldContent = $this->toEditContent( $oldtext );
            } else {
                $oldContent = null;
            }
        } else {
            $oldContent = $this->getCurrentContent();
        }

        $textboxContent = $this->toEditContent( $this->textbox1 );
        if ( $this->editRevId !== null ) {
            $newContent = $this->page->replaceSectionAtRev(
                $this->section, $textboxContent, $this->summary, $this->editRevId
            );
        } else {
            $newContent = $this->page->replaceSectionContent(
                $this->section, $textboxContent, $this->summary, $this->edittime
            );
        }

        if ( $newContent ) {
            ContentHandler::runLegacyHooks( 'EditPageGetDiffText', [ $this, &$newContent ] );
            Hooks::run( 'EditPageGetDiffContent', [ $this, &$newContent ] );

            $popts = ParserOptions::newFromUserAndLang( $wgUser, $wgContLang );
            $newContent = $newContent->preSaveTransform( $this->mTitle, $wgUser, $popts );
        }

        if ( ( $oldContent && !$oldContent->isEmpty() ) || ( $newContent && !$newContent->isEmpty() ) ) {
            $oldtitle = wfMessage( $oldtitlemsg )->parse();
            $newtitle = wfMessage( 'yourtext' )->parse();

            if ( !$oldContent ) {
                $oldContent = $newContent->getContentHandler()->makeEmptyContent();
            }

            if ( !$newContent ) {
                $newContent = $oldContent->getContentHandler()->makeEmptyContent();
            }

            $de = $oldContent->getContentHandler()->createDifferenceEngine( $this->mArticle->getContext() );
            $de->setContent( $oldContent, $newContent );

            $difftext = $de->getDiff( $oldtitle, $newtitle );
            $de->showDiffStyle();
        } else {
            $difftext = '';
        }

        $wgOut->addHTML( '<div id="wikiDiff">' . $difftext . '</div>' );
    }

    protected function showHeaderCopyrightWarning() {
        $msg = 'editpage-head-copy-warn';
        if ( !wfMessage( $msg )->isDisabled() ) {
            global $wgOut;
            $wgOut->wrapWikiMsg( "<div class='editpage-head-copywarn'>\n$1\n</div>",
                'editpage-head-copy-warn' );
        }
    }

    protected function showTosSummary() {
        $msg = 'editpage-tos-summary';
        Hooks::run( 'EditPageTosSummary', [ $this->mTitle, &$msg ] );
        if ( !wfMessage( $msg )->isDisabled() ) {
            global $wgOut;
            $wgOut->addHTML( '<div class="mw-tos-summary">' );
            $wgOut->addWikiMsg( $msg );
            $wgOut->addHTML( '</div>' );
        }
    }

    protected function showEditTools() {
        global $wgOut;
        $wgOut->addHTML( '<div class="mw-editTools">' .
            wfMessage( 'edittools' )->inContentLanguage()->parse() .
            '</div>' );
    }

    protected function getCopywarn() {
        return self::getCopyrightWarning( $this->mTitle );
    }

    public static function getCopyrightWarning( $title, $format = 'plain' ) {
        global $wgRightsText;
        if ( $wgRightsText ) {
            $copywarnMsg = [ 'copyrightwarning',
                '[[' . wfMessage( 'copyrightpage' )->inContentLanguage()->text() . ']]',
                $wgRightsText ];
        } else {
            $copywarnMsg = [ 'copyrightwarning2',
                '[[' . wfMessage( 'copyrightpage' )->inContentLanguage()->text() . ']]' ];
        }
        // Allow for site and per-namespace customization of contribution/copyright notice.
        Hooks::run( 'EditPageCopyrightWarning', [ $title, &$copywarnMsg ] );

        return "<div id=\"editpage-copywarn\">\n" .
            call_user_func_array( 'wfMessage', $copywarnMsg )->$format() . "\n</div>";
    }

    public static function getPreviewLimitReport( $output ) {
        if ( !$output || !$output->getLimitReportData() ) {
            return '';
        }

        $limitReport = Html::rawElement( 'div', [ 'class' => 'mw-limitReportExplanation' ],
            wfMessage( 'limitreport-title' )->parseAsBlock()
        );

        // Show/hide animation doesn't work correctly on a table, so wrap it in a div.
        $limitReport .= Html::openElement( 'div', [ 'class' => 'preview-limit-report-wrapper' ] );

        $limitReport .= Html::openElement( 'table', [
            'class' => 'preview-limit-report wikitable'
        ] ) .
            Html::openElement( 'tbody' );

        foreach ( $output->getLimitReportData() as $key => $value ) {
            if ( Hooks::run( 'ParserLimitReportFormat',
                [ $key, &$value, &$limitReport, true, true ]
            ) ) {
                $keyMsg = wfMessage( $key );
                $valueMsg = wfMessage( [ "$key-value-html", "$key-value" ] );
                if ( !$valueMsg->exists() ) {
                    $valueMsg = new RawMessage( '$1' );
                }
                if ( !$keyMsg->isDisabled() && !$valueMsg->isDisabled() ) {
                    $limitReport .= Html::openElement( 'tr' ) .
                        Html::rawElement( 'th', null, $keyMsg->parse() ) .
                        Html::rawElement( 'td', null, $valueMsg->params( $value )->parse() ) .
                        Html::closeElement( 'tr' );
                }
            }
        }

        $limitReport .= Html::closeElement( 'tbody' ) .
            Html::closeElement( 'table' ) .
            Html::closeElement( 'div' );

        return $limitReport;
    }

    protected function showStandardInputs( &$tabindex = 2 ) {
        global $wgOut;
        $wgOut->addHTML( "<div class='editOptions'>\n" );

        if ( $this->section != 'new' ) {
            $this->showSummaryInput( false, $this->summary );
            $wgOut->addHTML( $this->getSummaryPreview( false, $this->summary ) );
        }

        $checkboxes = $this->getCheckboxes( $tabindex,
            [ 'minor' => $this->minoredit, 'watch' => $this->watchthis ] );
        $wgOut->addHTML( "<div class='editCheckboxes'>" . implode( $checkboxes, "\n" ) . "</div>\n" );

        // Show copyright warning.
        $wgOut->addWikiText( $this->getCopywarn() );
        $wgOut->addHTML( $this->editFormTextAfterWarn );

        $wgOut->addHTML( "<div class='editButtons'>\n" );
        $wgOut->addHTML( implode( $this->getEditButtons( $tabindex ), "\n" ) . "\n" );

        $cancel = $this->getCancelLink();
        if ( $cancel !== '' ) {
            $cancel .= Html::element( 'span',
                [ 'class' => 'mw-editButtons-pipe-separator' ],
                wfMessage( 'pipe-separator' )->text() );
        }

        $message = wfMessage( 'edithelppage' )->inContentLanguage()->text();
        $edithelpurl = Skin::makeInternalOrExternalUrl( $message );
        $attrs = [
            'target' => 'helpwindow',
            'href' => $edithelpurl,
        ];
        $edithelp = Html::linkButton( wfMessage( 'edithelp' )->text(),
            $attrs, [ 'mw-ui-quiet' ] ) .
            wfMessage( 'word-separator' )->escaped() .
            wfMessage( 'newwindow' )->parse();

        $wgOut->addHTML( "  <span class='cancelLink'>{$cancel}</span>\n" );
        $wgOut->addHTML( "  <span class='editHelp'>{$edithelp}</span>\n" );
        $wgOut->addHTML( "</div><!-- editButtons -->\n" );

        Hooks::run( 'EditPage::showStandardInputs:options', [ $this, $wgOut, &$tabindex ] );

        $wgOut->addHTML( "</div><!-- editOptions -->\n" );
    }

    protected function showConflict() {
        global $wgOut;

        if ( Hooks::run( 'EditPageBeforeConflictDiff', [ &$this, &$wgOut ] ) ) {
            $stats = $wgOut->getContext()->getStats();
            $stats->increment( 'edit.failures.conflict' );
            // Only include 'standard' namespaces to avoid creating unknown numbers of statsd metrics
            if (
                $this->mTitle->getNamespace() >= NS_MAIN &&
                $this->mTitle->getNamespace() <= NS_CATEGORY_TALK
            ) {
                $stats->increment( 'edit.failures.conflict.byNamespaceId.' . $this->mTitle->getNamespace() );
            }

            $wgOut->wrapWikiMsg( '<h2>$1</h2>', "yourdiff" );

            $content1 = $this->toEditContent( $this->textbox1 );
            $content2 = $this->toEditContent( $this->textbox2 );

            $handler = ContentHandler::getForModelID( $this->contentModel );
            $de = $handler->createDifferenceEngine( $this->mArticle->getContext() );
            $de->setContent( $content2, $content1 );
            $de->showDiff(
                wfMessage( 'yourtext' )->parse(),
                wfMessage( 'storedversion' )->text()
            );

            $wgOut->wrapWikiMsg( '<h2>$1</h2>', "yourtext" );
            $this->showTextbox2();
        }
    }

    public function getCancelLink() {
        $cancelParams = [];
        if ( !$this->isConflict && $this->oldid > 0 ) {
            $cancelParams['oldid'] = $this->oldid;
        } elseif ( $this->getContextTitle()->isRedirect() ) {
            $cancelParams['redirect'] = 'no';
        }
        $attrs = [ 'id' => 'mw-editform-cancel' ];

        return Linker::linkKnown(
            $this->getContextTitle(),
            wfMessage( 'cancel' )->parse(),
            Html::buttonAttributes( $attrs, [ 'mw-ui-quiet' ] ),
            $cancelParams
        );
    }

    protected function getActionURL( Title $title ) {
        return $title->getLocalURL( [ 'action' => $this->action ] );
    }

    protected function wasDeletedSinceLastEdit() {
        if ( $this->deletedSinceEdit !== null ) {
            return $this->deletedSinceEdit;
        }

        $this->deletedSinceEdit = false;

        if ( !$this->mTitle->exists() && $this->mTitle->isDeletedQuick() ) {
            $this->lastDelete = $this->getLastDelete();
            if ( $this->lastDelete ) {
                $deleteTime = wfTimestamp( TS_MW, $this->lastDelete->log_timestamp );
                if ( $deleteTime > $this->starttime ) {
                    $this->deletedSinceEdit = true;
                }
            }
        }

        return $this->deletedSinceEdit;
    }

    protected function getLastDelete() {
        $dbr = wfGetDB( DB_SLAVE );
        $data = $dbr->selectRow(
            [ 'logging', 'user' ],
            [
                'log_type',
                'log_action',
                'log_timestamp',
                'log_user',
                'log_namespace',
                'log_title',
                'log_comment',
                'log_params',
                'log_deleted',
                'user_name'
            ], [
                'log_namespace' => $this->mTitle->getNamespace(),
                'log_title' => $this->mTitle->getDBkey(),
                'log_type' => 'delete',
                'log_action' => 'delete',
                'user_id=log_user'
            ],
            __METHOD__,
            [ 'LIMIT' => 1, 'ORDER BY' => 'log_timestamp DESC' ]
        );
        // Quick paranoid permission checks...
        if ( is_object( $data ) ) {
            if ( $data->log_deleted & LogPage::DELETED_USER ) {
                $data->user_name = wfMessage( 'rev-deleted-user' )->escaped();
            }

            if ( $data->log_deleted & LogPage::DELETED_COMMENT ) {
                $data->log_comment = wfMessage( 'rev-deleted-comment' )->escaped();
            }
        }

        return $data;
    }

    function getPreviewText() {
        global $wgOut, $wgRawHtml, $wgLang;
        global $wgAllowUserCss, $wgAllowUserJs;

        $stats = $wgOut->getContext()->getStats();

        if ( $wgRawHtml && !$this->mTokenOk ) {
            // Could be an offsite preview attempt. This is very unsafe if
            // HTML is enabled, as it could be an attack.
            $parsedNote = '';
            if ( $this->textbox1 !== '' ) {
                // Do not put big scary notice, if previewing the empty
                // string, which happens when you initially edit
                // a category page, due to automatic preview-on-open.
                $parsedNote = $wgOut->parse( "<div class='previewnote'>" .
                    wfMessage( 'session_fail_preview_html' )->text() . "</div>", true, /* interface */true );
            }
            $stats->increment( 'edit.failures.session_loss' );
            return $parsedNote;
        }

        $note = '';

        try {
            $content = $this->toEditContent( $this->textbox1 );

            $previewHTML = '';
            if ( !Hooks::run(
                'AlternateEditPreview',
                [ $this, &$content, &$previewHTML, &$this->mParserOutput ] )
            ) {
                return $previewHTML;
            }

            # provide a anchor link to the editform
            $continueEditing = '<span class="mw-continue-editing">' .
                '[[#' . self::EDITFORM_ID . '|' . $wgLang->getArrow() . ' ' .
                wfMessage( 'continue-editing' )->text() . ']]</span>';
            if ( $this->mTriedSave && !$this->mTokenOk ) {
                if ( $this->mTokenOkExceptSuffix ) {
                    $note = wfMessage( 'token_suffix_mismatch' )->plain();
                    $stats->increment( 'edit.failures.bad_token' );
                } else {
                    $note = wfMessage( 'session_fail_preview' )->plain();
                    $stats->increment( 'edit.failures.session_loss' );
                }
            } elseif ( $this->incompleteForm ) {
                $note = wfMessage( 'edit_form_incomplete' )->plain();
                if ( $this->mTriedSave ) {
                    $stats->increment( 'edit.failures.incomplete_form' );
                }
            } else {
                $note = wfMessage( 'previewnote' )->plain() . ' ' . $continueEditing;
            }

            # don't parse non-wikitext pages, show message about preview
            if ( $this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage() ) {
                if ( $this->mTitle->isCssJsSubpage() ) {
                    $level = 'user';
                } elseif ( $this->mTitle->isCssOrJsPage() ) {
                    $level = 'site';
                } else {
                    $level = false;
                }

                if ( $content->getModel() == CONTENT_MODEL_CSS ) {
                    $format = 'css';
                    if ( $level === 'user' && !$wgAllowUserCss ) {
                        $format = false;
                    }
                } elseif ( $content->getModel() == CONTENT_MODEL_JAVASCRIPT ) {
                    $format = 'js';
                    if ( $level === 'user' && !$wgAllowUserJs ) {
                        $format = false;
                    }
                } else {
                    $format = false;
                }

                # Used messages to make sure grep find them:
                # Messages: usercsspreview, userjspreview, sitecsspreview, sitejspreview
                if ( $level && $format ) {
                    $note = "<div id='mw-{$level}{$format}preview'>" .
                        wfMessage( "{$level}{$format}preview" )->text() .
                        ' ' . $continueEditing . "</div>";
                }
            }

            # If we're adding a comment, we need to show the
            # summary as the headline
            if ( $this->section === "new" && $this->summary !== "" ) {
                $content = $content->addSectionHeader( $this->summary );
            }

            $hook_args = [ $this, &$content ];
            ContentHandler::runLegacyHooks( 'EditPageGetPreviewText', $hook_args );
            Hooks::run( 'EditPageGetPreviewContent', $hook_args );

            $parserResult = $this->doPreviewParse( $content );
            $parserOutput = $parserResult['parserOutput'];
            $previewHTML = $parserResult['html'];
            $this->mParserOutput = $parserOutput;
            $wgOut->addParserOutputMetadata( $parserOutput );

            if ( count( $parserOutput->getWarnings() ) ) {
                $note .= "\n\n" . implode( "\n\n", $parserOutput->getWarnings() );
            }

        } catch ( MWContentSerializationException $ex ) {
            $m = wfMessage(
                'content-failed-to-parse',
                $this->contentModel,
                $this->contentFormat,
                $ex->getMessage()
            );
            $note .= "\n\n" . $m->parse();
            $previewHTML = '';
        }

        if ( $this->isConflict ) {
            $conflict = '<h2 id="mw-previewconflict">'
                . wfMessage( 'previewconflict' )->escaped() . "</h2>\n";
        } else {
            $conflict = '<hr />';
        }

        $previewhead = "<div class='previewnote'>\n" .
            '<h2 id="mw-previewheader">' . wfMessage( 'preview' )->escaped() . "</h2>" .
            $wgOut->parse( $note, true, /* interface */true ) . $conflict . "</div>\n";

        $pageViewLang = $this->mTitle->getPageViewLanguage();
        $attribs = [ 'lang' => $pageViewLang->getHtmlCode(), 'dir' => $pageViewLang->getDir(),
            'class' => 'mw-content-' . $pageViewLang->getDir() ];
        $previewHTML = Html::rawElement( 'div', $attribs, $previewHTML );

        return $previewhead . $previewHTML . $this->previewTextAfterContent;
    }

    protected function getPreviewParserOptions() {
        $parserOptions = $this->page->makeParserOptions( $this->mArticle->getContext() );
        $parserOptions->setIsPreview( true );
        $parserOptions->setIsSectionPreview( !is_null( $this->section ) && $this->section !== '' );
        $parserOptions->enableLimitReport();
        return $parserOptions;
    }

    protected function doPreviewParse( Content $content ) {
        global $wgUser;
        $parserOptions = $this->getPreviewParserOptions();
        $pstContent = $content->preSaveTransform( $this->mTitle, $wgUser, $parserOptions );
        $scopedCallback = $parserOptions->setupFakeRevision(
            $this->mTitle, $pstContent, $wgUser );
        $parserOutput = $pstContent->getParserOutput( $this->mTitle, null, $parserOptions );
        ScopedCallback::consume( $scopedCallback );
        $parserOutput->setEditSectionTokens( false ); // no section edit links
        return [
            'parserOutput' => $parserOutput,
            'html' => $parserOutput->getText() ];
    }

    function getTemplates() {
        if ( $this->preview || $this->section != '' ) {
            $templates = [];
            if ( !isset( $this->mParserOutput ) ) {
                return $templates;
            }
            foreach ( $this->mParserOutput->getTemplates() as $ns => $template ) {
                foreach ( array_keys( $template ) as $dbk ) {
                    $templates[] = Title::makeTitle( $ns, $dbk );
                }
            }
            return $templates;
        } else {
            return $this->mTitle->getTemplateLinksFrom();
        }
    }

    static function getEditToolbar( $title = null ) {
        global $wgContLang, $wgOut;
        global $wgEnableUploads, $wgForeignFileRepos;

        $imagesAvailable = $wgEnableUploads || count( $wgForeignFileRepos );
        $showSignature = true;
        if ( $title ) {
            $showSignature = MWNamespace::wantSignatures( $title->getNamespace() );
        }

        $toolarray = [
            [
                'id'     => 'mw-editbutton-bold',
                'open'   => '\'\'\'',
                'close'  => '\'\'\'',
                'sample' => wfMessage( 'bold_sample' )->text(),
                'tip'    => wfMessage( 'bold_tip' )->text(),
            ],
            [
                'id'     => 'mw-editbutton-italic',
                'open'   => '\'\'',
                'close'  => '\'\'',
                'sample' => wfMessage( 'italic_sample' )->text(),
                'tip'    => wfMessage( 'italic_tip' )->text(),
            ],
            [
                'id'     => 'mw-editbutton-link',
                'open'   => '[[',
                'close'  => ']]',
                'sample' => wfMessage( 'link_sample' )->text(),
                'tip'    => wfMessage( 'link_tip' )->text(),
            ],
            [
                'id'     => 'mw-editbutton-extlink',
                'open'   => '[',
                'close'  => ']',
                'sample' => wfMessage( 'extlink_sample' )->text(),
                'tip'    => wfMessage( 'extlink_tip' )->text(),
            ],
            [
                'id'     => 'mw-editbutton-headline',
                'open'   => "\n== ",
                'close'  => " ==\n",
                'sample' => wfMessage( 'headline_sample' )->text(),
                'tip'    => wfMessage( 'headline_tip' )->text(),
            ],
            $imagesAvailable ? [
                'id'     => 'mw-editbutton-image',
                'open'   => '[[' . $wgContLang->getNsText( NS_FILE ) . ':',
                'close'  => ']]',
                'sample' => wfMessage( 'image_sample' )->text(),
                'tip'    => wfMessage( 'image_tip' )->text(),
            ] : false,
            $imagesAvailable ? [
                'id'     => 'mw-editbutton-media',
                'open'   => '[[' . $wgContLang->getNsText( NS_MEDIA ) . ':',
                'close'  => ']]',
                'sample' => wfMessage( 'media_sample' )->text(),
                'tip'    => wfMessage( 'media_tip' )->text(),
            ] : false,
            [
                'id'     => 'mw-editbutton-nowiki',
                'open'   => "<nowiki>",
                'close'  => "</nowiki>",
                'sample' => wfMessage( 'nowiki_sample' )->text(),
                'tip'    => wfMessage( 'nowiki_tip' )->text(),
            ],
            $showSignature ? [
                'id'     => 'mw-editbutton-signature',
                'open'   => wfMessage( 'sig-text', '~~~~' )->inContentLanguage()->text(),
                'close'  => '',
                'sample' => '',
                'tip'    => wfMessage( 'sig_tip' )->text(),
            ] : false,
            [
                'id'     => 'mw-editbutton-hr',
                'open'   => "\n----\n",
                'close'  => '',
                'sample' => '',
                'tip'    => wfMessage( 'hr_tip' )->text(),
            ]
        ];

        $script = 'mw.loader.using("mediawiki.toolbar", function () {';
        foreach ( $toolarray as $tool ) {
            if ( !$tool ) {
                continue;
            }

            $params = [
                // Images are defined in ResourceLoaderEditToolbarModule
                false,
                // Note that we use the tip both for the ALT tag and the TITLE tag of the image.
                // Older browsers show a "speedtip" type message only for ALT.
                // Ideally these should be different, realistically they
                // probably don't need to be.
                $tool['tip'],
                $tool['open'],
                $tool['close'],
                $tool['sample'],
                $tool['id'],
            ];

            $script .= Xml::encodeJsCall(
                'mw.toolbar.addButton',
                $params,
                ResourceLoader::inDebugMode()
            );
        }

        $script .= '});';
        $wgOut->addScript( ResourceLoader::makeInlineScript( $script ) );

        $toolbar = '<div id="toolbar"></div>';

        Hooks::run( 'EditPageBeforeEditToolbar', [ &$toolbar ] );

        return $toolbar;
    }

    public function getCheckboxes( &$tabindex, $checked ) {
        global $wgUser, $wgUseMediaWikiUIEverywhere;

        $checkboxes = [];

        // don't show the minor edit checkbox if it's a new page or section
        if ( !$this->isNew ) {
            $checkboxes['minor'] = '';
            $minorLabel = wfMessage( 'minoredit' )->parse();
            if ( $wgUser->isAllowed( 'minoredit' ) ) {
                $attribs = [
                    'tabindex' => ++$tabindex,
                    'accesskey' => wfMessage( 'accesskey-minoredit' )->text(),
                    'id' => 'wpMinoredit',
                ];
                $minorEditHtml =
                    Xml::check( 'wpMinoredit', $checked['minor'], $attribs ) .
                    "&#160;<label for='wpMinoredit' id='mw-editpage-minoredit'" .
                    Xml::expandAttributes( [ 'title' => Linker::titleAttrib( 'minoredit', 'withaccess' ) ] ) .
                    ">{$minorLabel}</label>";

                if ( $wgUseMediaWikiUIEverywhere ) {
                    $checkboxes['minor'] = Html::openElement( 'div', [ 'class' => 'mw-ui-checkbox' ] ) .
                        $minorEditHtml .
                    Html::closeElement( 'div' );
                } else {
                    $checkboxes['minor'] = $minorEditHtml;
                }
            }
        }

        $watchLabel = wfMessage( 'watchthis' )->parse();
        $checkboxes['watch'] = '';
        if ( $wgUser->isLoggedIn() ) {
            $attribs = [
                'tabindex' => ++$tabindex,
                'accesskey' => wfMessage( 'accesskey-watch' )->text(),
                'id' => 'wpWatchthis',
            ];
            $watchThisHtml =
                Xml::check( 'wpWatchthis', $checked['watch'], $attribs ) .
                "&#160;<label for='wpWatchthis' id='mw-editpage-watch'" .
                Xml::expandAttributes( [ 'title' => Linker::titleAttrib( 'watch', 'withaccess' ) ] ) .
                ">{$watchLabel}</label>";
            if ( $wgUseMediaWikiUIEverywhere ) {
                $checkboxes['watch'] = Html::openElement( 'div', [ 'class' => 'mw-ui-checkbox' ] ) .
                    $watchThisHtml .
                    Html::closeElement( 'div' );
            } else {
                $checkboxes['watch'] = $watchThisHtml;
            }
        }
        Hooks::run( 'EditPageBeforeEditChecks', [ &$this, &$checkboxes, &$tabindex ] );
        return $checkboxes;
    }

    public function getEditButtons( &$tabindex ) {
        $buttons = [];

        $attribs = [
            'id' => 'wpSave',
            'name' => 'wpSave',
            'tabindex' => ++$tabindex,
        ] + Linker::tooltipAndAccesskeyAttribs( 'save' );
        $buttons['save'] = Html::submitButton( wfMessage( 'savearticle' )->text(),
            $attribs, [ 'mw-ui-constructive' ] );

        ++$tabindex; // use the same for preview and live preview
        $attribs = [
            'id' => 'wpPreview',
            'name' => 'wpPreview',
            'tabindex' => $tabindex,
        ] + Linker::tooltipAndAccesskeyAttribs( 'preview' );
        $buttons['preview'] = Html::submitButton( wfMessage( 'showpreview' )->text(),
            $attribs );
        $buttons['live'] = '';

        $attribs = [
            'id' => 'wpDiff',
            'name' => 'wpDiff',
            'tabindex' => ++$tabindex,
        ] + Linker::tooltipAndAccesskeyAttribs( 'diff' );
        $buttons['diff'] = Html::submitButton( wfMessage( 'showdiff' )->text(),
            $attribs );

        Hooks::run( 'EditPageBeforeEditButtons', [ &$this, &$buttons, &$tabindex ] );
        return $buttons;
    }

    function noSuchSectionPage() {
        global $wgOut;

        $wgOut->prepareErrorPage( wfMessage( 'nosuchsectiontitle' ) );

        $res = wfMessage( 'nosuchsectiontext', $this->section )->parseAsBlock();
        Hooks::run( 'EditPageNoSuchSection', [ &$this, &$res ] );
        $wgOut->addHTML( $res );

        $wgOut->returnToMain( false, $this->mTitle );
    }

    public function spamPageWithContent( $match = false ) {
        global $wgOut, $wgLang;
        $this->textbox2 = $this->textbox1;

        if ( is_array( $match ) ) {
            $match = $wgLang->listToText( $match );
        }
        $wgOut->prepareErrorPage( wfMessage( 'spamprotectiontitle' ) );

        $wgOut->addHTML( '<div id="spamprotected">' );
        $wgOut->addWikiMsg( 'spamprotectiontext' );
        if ( $match ) {
            $wgOut->addWikiMsg( 'spamprotectionmatch', wfEscapeWikiText( $match ) );
        }
        $wgOut->addHTML( '</div>' );

        $wgOut->wrapWikiMsg( '<h2>$1</h2>', "yourdiff" );
        $this->showDiff();

        $wgOut->wrapWikiMsg( '<h2>$1</h2>', "yourtext" );
        $this->showTextbox2();

        $wgOut->addReturnTo( $this->getContextTitle(), [ 'action' => 'edit' ] );
    }

    private function checkUnicodeCompliantBrowser() {
        global $wgBrowserBlackList, $wgRequest;

        $currentbrowser = $wgRequest->getHeader( 'User-Agent' );
        if ( $currentbrowser === false ) {
            // No User-Agent header sent? Trust it by default...
            return true;
        }

        foreach ( $wgBrowserBlackList as $browser ) {
            if ( preg_match( $browser, $currentbrowser ) ) {
                return false;
            }
        }
        return true;
    }

    protected function safeUnicodeInput( $request, $field ) {
        $text = rtrim( $request->getText( $field ) );
        return $request->getBool( 'safemode' )
            ? $this->unmakeSafe( $text )
            : $text;
    }

    protected function safeUnicodeOutput( $text ) {
        return $this->checkUnicodeCompliantBrowser()
            ? $text
            : $this->makesafe( $text );
    }

    private function makeSafe( $invalue ) {
        // Armor existing references for reversibility.
        $invalue = strtr( $invalue, [ "&#x" => "&#x0" ] );

        $bytesleft = 0;
        $result = "";
        $working = 0;
        $valueLength = strlen( $invalue );
        for ( $i = 0; $i < $valueLength; $i++ ) {
            $bytevalue = ord( $invalue[$i] );
            if ( $bytevalue <= 0x7F ) { // 0xxx xxxx
                $result .= chr( $bytevalue );
                $bytesleft = 0;
            } elseif ( $bytevalue <= 0xBF ) { // 10xx xxxx
                $working = $working << 6;
                $working += ( $bytevalue & 0x3F );
                $bytesleft--;
                if ( $bytesleft <= 0 ) {
                    $result .= "&#x" . strtoupper( dechex( $working ) ) . ";";
                }
            } elseif ( $bytevalue <= 0xDF ) { // 110x xxxx
                $working = $bytevalue & 0x1F;
                $bytesleft = 1;
            } elseif ( $bytevalue <= 0xEF ) { // 1110 xxxx
                $working = $bytevalue & 0x0F;
                $bytesleft = 2;
            } else { // 1111 0xxx
                $working = $bytevalue & 0x07;
                $bytesleft = 3;
            }
        }
        return $result;
    }

    private function unmakeSafe( $invalue ) {
        $result = "";
        $valueLength = strlen( $invalue );
        for ( $i = 0; $i < $valueLength; $i++ ) {
            if ( ( substr( $invalue, $i, 3 ) == "&#x" ) && ( $invalue[$i + 3] != '0' ) ) {
                $i += 3;
                $hexstring = "";
                do {
                    $hexstring .= $invalue[$i];
                    $i++;
                } while ( ctype_xdigit( $invalue[$i] ) && ( $i < strlen( $invalue ) ) );

                // Do some sanity checks. These aren't needed for reversibility,
                // but should help keep the breakage down if the editor
                // breaks one of the entities whilst editing.
                if ( ( substr( $invalue, $i, 1 ) == ";" ) && ( strlen( $hexstring ) <= 6 ) ) {
                    $codepoint = hexdec( $hexstring );
                    $result .= UtfNormal\Utils::codepointToUtf8( $codepoint );
                } else {
                    $result .= "&#x" . $hexstring . substr( $invalue, $i, 1 );
                }
            } else {
                $result .= substr( $invalue, $i, 1 );
            }
        }
        // reverse the transform that we made for reversibility reasons.
        return strtr( $result, [ "&#x0" => "&#x" ] );
    }
}