Merge "RELEASE-NOTES: Add release note for 74fa607"

[lhc/web/wiklou.git] / includes / EditPage.php

<?php
/**
 * User interface for page editing.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

use MediaWiki\Logger\LoggerFactory;

/**
 * The edit page/HTML interface (split from Article)
 * The actual database and text munging is still in Article,
 * but it should get easier to call those from alternate
 * interfaces.
 *
 * EditPage cares about two distinct titles:
 * $this->mContextTitle is the page that forms submit to, links point to,
 * redirects go to, etc. $this->mTitle (as well as $mArticle) is the
 * page in the database that is actually being edited. These are
 * usually the same, but they are now allowed to be different.
 *
 * Surgeon General's Warning: prolonged exposure to this class is known to cause
 * headaches, which may be fatal.
 */
class EditPage {
        /**
         * Status: Article successfully updated
         */
        const AS_SUCCESS_UPDATE = 200;

        /**
         * Status: Article successfully created
         */
        const AS_SUCCESS_NEW_ARTICLE = 201;

        /**
         * Status: Article update aborted by a hook function
         */
        const AS_HOOK_ERROR = 210;

        /**
         * Status: A hook function returned an error
         */
        const AS_HOOK_ERROR_EXPECTED = 212;

        /**
         * Status: User is blocked from editing this page
         */
        const AS_BLOCKED_PAGE_FOR_USER = 215;

        /**
         * Status: Content too big (> $wgMaxArticleSize)
         */
        const AS_CONTENT_TOO_BIG = 216;

        /**
         * Status: this anonymous user is not allowed to edit this page
         */
        const AS_READ_ONLY_PAGE_ANON = 218;

        /**
         * Status: this logged in user is not allowed to edit this page
         */
        const AS_READ_ONLY_PAGE_LOGGED = 219;

        /**
         * Status: wiki is in readonly mode (wfReadOnly() == true)
         */
        const AS_READ_ONLY_PAGE = 220;

        /**
         * Status: rate limiter for action 'edit' was tripped
         */
        const AS_RATE_LIMITED = 221;

        /**
         * Status: article was deleted while editing and param wpRecreate == false or form
         * was not posted
         */
        const AS_ARTICLE_WAS_DELETED = 222;

        /**
         * Status: user tried to create this page, but is not allowed to do that
         * ( Title->userCan('create') == false )
         */
        const AS_NO_CREATE_PERMISSION = 223;

        /**
         * Status: user tried to create a blank page and wpIgnoreBlankArticle == false
         */
        const AS_BLANK_ARTICLE = 224;

        /**
         * Status: (non-resolvable) edit conflict
         */
        const AS_CONFLICT_DETECTED = 225;

        /**
         * Status: no edit summary given and the user has forceeditsummary set and the user is not
         * editing in his own userspace or talkspace and wpIgnoreBlankSummary == false
         */
        const AS_SUMMARY_NEEDED = 226;

        /**
         * Status: user tried to create a new section without content
         */
        const AS_TEXTBOX_EMPTY = 228;

        /**
         * Status: article is too big (> $wgMaxArticleSize), after merging in the new section
         */
        const AS_MAX_ARTICLE_SIZE_EXCEEDED = 229;

        /**
         * Status: WikiPage::doEdit() was unsuccessful
         */
        const AS_END = 231;

        /**
         * Status: summary contained spam according to one of the regexes in $wgSummarySpamRegex
         */
        const AS_SPAM_ERROR = 232;

        /**
         * Status: anonymous user is not allowed to upload (User::isAllowed('upload') == false)
         */
        const AS_IMAGE_REDIRECT_ANON = 233;

        /**
         * Status: logged in user is not allowed to upload (User::isAllowed('upload') == false)
         */
        const AS_IMAGE_REDIRECT_LOGGED = 234;

        /**
         * Status: user tried to modify the content model, but is not allowed to do that
         * ( User::isAllowed('editcontentmodel') == false )
         */
        const AS_NO_CHANGE_CONTENT_MODEL = 235;

        /**
         * Status: user tried to create self-redirect (redirect to the same article) and
         * wpIgnoreSelfRedirect == false
         */
        const AS_SELF_REDIRECT = 236;

        /**
         * Status: an error relating to change tagging. Look at the message key for
         * more details
         */
        const AS_CHANGE_TAG_ERROR = 237;

        /**
         * Status: can't parse content
         */
        const AS_PARSE_ERROR = 240;

        /**
         * Status: when changing the content model is disallowed due to
         * $wgContentHandlerUseDB being false
         */
        const AS_CANNOT_USE_CUSTOM_MODEL = 241;

        /**
         * HTML id and name for the beginning of the edit form.
         */
        const EDITFORM_ID = 'editform';

        /**
         * Prefix of key for cookie used to pass post-edit state.
         * The revision id edited is added after this
         */
        const POST_EDIT_COOKIE_KEY_PREFIX = 'PostEditRevision';

        /**
         * Duration of PostEdit cookie, in seconds.
         * The cookie will be removed instantly if the JavaScript runs.
         *
         * Otherwise, though, we don't want the cookies to accumulate.
         * RFC 2109 ( https://www.ietf.org/rfc/rfc2109.txt ) specifies a possible
         * limit of only 20 cookies per domain. This still applies at least to some
         * versions of IE without full updates:
         * https://blogs.msdn.com/b/ieinternals/archive/2009/08/20/wininet-ie-cookie-internals-faq.aspx
         *
         * A value of 20 minutes should be enough to take into account slow loads and minor
         * clock skew while still avoiding cookie accumulation when JavaScript is turned off.
         */
        const POST_EDIT_COOKIE_DURATION = 1200;

        /** @var Article */
        public $mArticle;
        /** @var WikiPage */
        private $page;

        /** @var Title */
        public $mTitle;

        /** @var null|Title */
        private $mContextTitle = null;

        /** @var string */
        public $action = 'submit';

        /** @var bool */
        public $isConflict = false;

        /** @var bool */
        public $isCssJsSubpage = false;

        /** @var bool */
        public $isCssSubpage = false;

        /** @var bool */
        public $isJsSubpage = false;

        /** @var bool */
        public $isWrongCaseCssJsPage = false;

        /** @var bool New page or new section */
        public $isNew = false;

        /** @var bool */
        public $deletedSinceEdit;

        /** @var string */
        public $formtype;

        /** @var bool */
        public $firsttime;

        /** @var bool|stdClass */
        public $lastDelete;

        /** @var bool */
        public $mTokenOk = false;

        /** @var bool */
        public $mTokenOkExceptSuffix = false;

        /** @var bool */
        public $mTriedSave = false;

        /** @var bool */
        public $incompleteForm = false;

        /** @var bool */
        public $tooBig = false;

        /** @var bool */
        public $missingComment = false;

        /** @var bool */
        public $missingSummary = false;

        /** @var bool */
        public $allowBlankSummary = false;

        /** @var bool */
        protected $blankArticle = false;

        /** @var bool */
        protected $allowBlankArticle = false;

        /** @var bool */
        protected $selfRedirect = false;

        /** @var bool */
        protected $allowSelfRedirect = false;

        /** @var string */
        public $autoSumm = '';

        /** @var string */
        public $hookError = '';

        /** @var ParserOutput */
        public $mParserOutput;

        /** @var bool Has a summary been preset using GET parameter &summary= ? */
        public $hasPresetSummary = false;

        /** @var bool */
        public $mBaseRevision = false;

        /** @var bool */
        public $mShowSummaryField = true;

        # Form values

        /** @var bool */
        public $save = false;

        /** @var bool */
        public $preview = false;

        /** @var bool */
        public $diff = false;

        /** @var bool */
        public $minoredit = false;

        /** @var bool */
        public $watchthis = false;

        /** @var bool */
        public $recreate = false;

        /** @var string */
        public $textbox1 = '';

        /** @var string */
        public $textbox2 = '';

        /** @var string */
        public $summary = '';

        /** @var bool */
        public $nosummary = false;

        /** @var string */
        public $edittime = '';

        /** @var integer */
        private $editRevId = null;

        /** @var string */
        public $section = '';

        /** @var string */
        public $sectiontitle = '';

        /** @var string */
        public $starttime = '';

        /** @var int */
        public $oldid = 0;

        /** @var int */
        public $parentRevId = 0;

        /** @var string */
        public $editintro = '';

        /** @var null */
        public $scrolltop = null;

        /** @var bool */
        public $bot = true;

        /** @var null|string */
        public $contentModel = null;

        /** @var null|string */
        public $contentFormat = null;

        /** @var null|array */
        private $changeTags = null;

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

        /** @var string Before even the preview */
        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;

        /** @var bool */
        protected $edit;

        /** @var bool|int */
        protected $contentLength = false;

        /**
         * @var bool Set in ApiEditPage, based on ContentHandler::allowsDirectApiEditing
         */
        private $enableApiEditOverride = false;

        /**
         * @var IContextSource
         */
        protected $context;

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

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

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

        /**
         * @return Article
         */
        public function getArticle() {
                return $this->mArticle;
        }

        /**
         * @since 1.28
         * @return IContextSource
         */
        public function getContext() {
                return $this->context;
        }

        /**
         * @since 1.19
         * @return Title
         */
        public function getTitle() {
                return $this->mTitle;
        }

        /**
         * Set the context Title object
         *
         * @param Title|null $title Title object or null
         */
        public function setContextTitle( $title ) {
                $this->mContextTitle = $title;
        }

        /**
         * Get the context title object.
         * If not set, $wgTitle will be returned. This behavior might change in
         * the future to return $this->mTitle instead.
         *
         * @return Title
         */
        public function getContextTitle() {
                if ( is_null( $this->mContextTitle ) ) {
                        global $wgTitle;
                        return $wgTitle;
                } else {
                        return $this->mContextTitle;
                }
        }

        /**
         * Returns if the given content model is editable.
         *
         * @param string $modelId The ID of the content model to test. Use CONTENT_MODEL_XXX constants.
         * @return bool
         * @throws MWException If $modelId has no known handler
         */
        public function isSupportedContentModel( $modelId ) {
                return $this->enableApiEditOverride === true ||
                        ContentHandler::getForModelID( $modelId )->supportsDirectEditing();
        }

        /**
         * Allow editing of content that supports API direct editing, but not general
         * direct editing. Set to false by default.
         *
         * @param bool $enableOverride
         */
        public function setApiEditOverride( $enableOverride ) {
                $this->enableApiEditOverride = $enableOverride;
        }

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

        /**
         * This is the function that gets called for "action=edit". It
         * sets up various member variables, then passes execution to
         * another function, usually showEditForm()
         *
         * The edit form is self-submitting, so that when things like
         * preview and edit conflicts occur, we get the same form back
         * with the extra stuff added.  Only when the final submission
         * is made and all is well do we actually save and redirect to
         * the newly-edited page.
         */
        function edit() {
                // Allow extensions to modify/prevent this form or submission
                if ( !Hooks::run( 'AlternateEdit', [ $this ] ) ) {
                        return;
                }

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

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

                $this->importFormData( $request );
                $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 = $this->context->getUser();
                                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();
        }

        /**
         * @param string $rigor Same format as Title::getUserPermissionErrors()
         * @return array
         */
        protected function getEditPermissionErrors( $rigor = 'secure' ) {
                $user = $this->context->getUser();
                $permErrors = $this->mTitle->getUserPermissionsErrors( 'edit', $user, $rigor );
                # Can this title be created?
                if ( !$this->mTitle->exists() ) {
                        $permErrors = array_merge(
                                $permErrors,
                                wfArrayDiff2(
                                        $this->mTitle->getUserPermissionsErrors( 'create', $user, $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;
        }

        /**
         * Display a permissions error page, like OutputPage::showPermissionsErrorPage(),
         * but with the following differences:
         * - If redlink=1, the user will be redirected to the page
         * - If there is content to display or the error occurs while either saving,
         *   previewing or showing the difference, it will be a
         *   "View source for ..." page displaying the source code after the error message.
         *
         * @since 1.19
         * @param array $permErrors Array of permissions errors, as returned by
         *    Title::getUserPermissionsErrors().
         * @throws PermissionsError
         */
        protected function displayPermissionsError( array $permErrors ) {
                $out = $this->context->getOutput();
                if ( $this->context->getRequest()->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.
                        $out->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,
                        $out->formatPermissionsErrorMessage( $permErrors, 'edit' )
                );
        }

        /**
         * Display a read-only View Source page
         * @param Content $content content object
         * @param string $errorMessage additional wikitext error message to display
         */
        protected function displayViewSourcePage( Content $content, $errorMessage = '' ) {
                $out = $this->context->getOutput();
                Hooks::run( 'EditPage::showReadOnlyForm:initial', [ $this, &$out ] );

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

                if ( $errorMessage !== '' ) {
                        $out->addWikiText( $errorMessage );
                        $out->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;
                        $out->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();
                        }
                        $out->addWikiMsg( 'viewsourcetext' );
                }

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

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

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

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

        /**
         * Should we show a preview when the edit form is first shown?
         *
         * @return bool
         */
        protected function previewOnOpen() {
                global $wgPreviewOnOpenNamespaces;
                $request = $this->context->getRequest();
                if ( $request->getVal( 'preview' ) == 'yes' ) {
                        // Explicit override from request
                        return true;
                } elseif ( $request->getVal( 'preview' ) == 'no' ) {
                        // Explicit override from request
                        return false;
                } elseif ( $this->section == 'new' ) {
                        // Nothing *to* preview for new sections
                        return false;
                } elseif ( ( $request->getVal( 'preload' ) !== null || $this->mTitle->exists() )
                        && $this->context->getUser()->getOption( 'previewonfirst' )
                ) {
                        // Standard preference behavior
                        return true;
                } elseif ( !$this->mTitle->exists()
                        && isset( $wgPreviewOnOpenNamespaces[$this->mTitle->getNamespace()] )
                        && $wgPreviewOnOpenNamespaces[$this->mTitle->getNamespace()]
                ) {
                        // Categories are special
                        return true;
                } else {
                        return false;
                }
        }

        /**
         * Checks whether the user entered a skin name in uppercase,
         * e.g. "User:Example/Monobook.css" instead of "monobook.css"
         *
         * @return bool
         */
        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;
                }
        }

        /**
         * Returns whether section editing is supported for the current page.
         * Subclasses may override this to replace the default behavior, which is
         * to check ContentHandler::supportsSections.
         *
         * @return bool True if this edit page supports sections, false otherwise.
         */
        protected function isSectionEditSupported() {
                $contentHandler = ContentHandler::getForTitle( $this->mTitle );
                return $contentHandler->supportsSections();
        }

        /**
         * This function collects the form data and uses it to populate various member variables.
         * @param WebRequest $request
         * @throws ErrorPageError
         */
        function importFormData( &$request ) {
                global $wgContLang;

                # 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
                        $user = $this->context->getUser();
                        if ( ( $this->mTitle->mNamespace == NS_USER || $this->mTitle->mNamespace == NS_USER_TALK )
                                && $this->mTitle->getText() == $user->getName()
                        ) {
                                $this->allowBlankSummary = true;
                        } else {
                                $this->allowBlankSummary = $request->getBool( 'wpIgnoreBlankSummary' )
                                        || !$user->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 ) ]
                        );
                }

                /**
                 * @todo Check if the desired model is allowed in this namespace, and if
                 *   a transition from the page's current model to the new model is
                 *   allowed.
                 */

                $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 ] );

        }

        /**
         * Subpage overridable method for extracting the page content data from the
         * posted form to be placed in $this->textbox1, if using customized input
         * this method should be overridden and return the page text that will be used
         * for saving, preview parsing and so on...
         *
         * @param WebRequest $request
         * @return string|null
         */
        protected function importContentFormData( &$request ) {
                return; // Don't do anything, EditPage already extracted wpTextbox1
        }

        /**
         * Initialise form fields in the object
         * Called on the first invocation, e.g. when a user clicks an edit link
         * @return bool If the requested section is valid
         */
        function initialiseForm() {
                $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 );
                $user = $this->context->getUser();

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

        /**
         * @param Content|null $def_content The default value to return
         *
         * @return Content|null Content on success, $def_content for invalid sections
         *
         * @since 1.21
         */
        protected function getContentObject( $def_content = null ) {
                global $wgContLang;

                $content = false;
                $request = $this->context->getRequest();
                $user = $this->context->getUser();

                // 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 = $request->getVal( 'preload',
                                        // Custom preload text for new sections
                                        $this->section === 'new' ? 'MediaWiki:addsection-preload' : '' );
                                $params = $request->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( $user );
                                $content = $orig ? $orig->getSection( $this->section ) : null;

                                if ( !$content ) {
                                        $content = $def_content;
                                }
                        } else {
                                $undoafter = $request->getInt( 'undoafter' );
                                $undo = $request->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( $user, $wgContLang );
                                                        $newContent = $content->preSaveTransform( $this->mTitle, $user, $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 .= $this->context->getOutput()->parse(
                                                "<div class=\"{$class}\">" .
                                                wfMessage( 'undo-' . $undoMsg )->plain() . '</div>', true, /* interface */true );
                                }

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

                return $content;
        }

        /**
         * Get the content of the wanted revision, without section extraction.
         *
         * The result of this function can be used to compare user's input with
         * section replaced in its context (using WikiPage::replaceSectionAtRev())
         * to the original text of the edit.
         *
         * This differs from Article::getContent() that when a missing revision is
         * encountered the result will be null and not the
         * 'missing-revision' message.
         *
         * @since 1.19
         * @param User $user The user to get the revision for
         * @return Content|null
         */
        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;
        }

        /**
         * Get the edit's parent revision ID
         *
         * The "parent" revision is the ancestor that should be recorded in this
         * page's revision history.  It is either the revision ID of the in-memory
         * article content, or in the case of a 3-way merge in order to rebase
         * across a recoverable edit conflict, the ID of the newer revision to
         * which we have rebased this page.
         *
         * @since 1.27
         * @return int Revision ID
         */
        public function getParentRevId() {
                if ( $this->parentRevId ) {
                        return $this->parentRevId;
                } else {
                        return $this->mArticle->getRevIdFetched();
                }
        }

        /**
         * Get the current content of the page. This is basically similar to
         * WikiPage::getContent( Revision::RAW ) except that when the page doesn't exist an empty
         * content object is returned instead of null.
         *
         * @since 1.21
         * @return Content
         */
        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;
                }
        }

        /**
         * Use this method before edit() to preload some content into the edit box
         *
         * @param Content $content
         *
         * @since 1.21
         */
        public function setPreloadedContent( Content $content ) {
                $this->mPreloadContent = $content;
        }

        /**
         * Get the contents to be preloaded into the box, either set by
         * an earlier setPreloadText() or by loading the given page.
         *
         * @param string $preload Representing the title to preload from.
         * @param array $params Parameters to use (interface-message style) in the preloaded text
         *
         * @return Content
         *
         * @since 1.21
         */
        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 );
        }

        /**
         * Make sure the form isn't faking a user's credentials.
         *
         * @param WebRequest $request
         * @return bool
         * @private
         */
        function tokenOk( &$request ) {
                $token = $request->getVal( 'wpEditToken' );
                $user = $this->context->getUser();
                $this->mTokenOk = $user->matchEditToken( $token );
                $this->mTokenOkExceptSuffix = $user->matchEditTokenNoSuffix( $token );
                return $this->mTokenOk;
        }

        /**
         * Sets post-edit cookie indicating the user just saved a particular revision.
         *
         * This uses a temporary cookie for each revision ID so separate saves will never
         * interfere with each other.
         *
         * The cookie is deleted in the mediawiki.action.view.postEdit JS module after
         * the redirect.  It must be clearable by JavaScript code, so it must not be
         * marked HttpOnly. The JavaScript code converts the cookie to a wgPostEdit config
         * variable.
         *
         * If the variable were set on the server, it would be cached, which is unwanted
         * since the post-edit state should only apply to the load right after the save.
         *
         * @param int $statusValue The status value (to check for new article status)
         */
        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 = $this->context->getRequest()->response();
                $response->setCookie( $postEditKey, $val, time() + self::POST_EDIT_COOKIE_DURATION, [
                        'httpOnly' => false,
                ] );
        }

        /**
         * Attempt submission
         * @param array|bool $resultDetails See docs for $result in internalAttemptSave
         * @throws UserBlockedError|ReadOnlyError|ThrottledError|PermissionsError
         * @return Status The resulting status object.
         */
        public function attemptSave( &$resultDetails = false ) {
                # Allow bots to exempt some edits from bot flagging
                $bot = $this->context->getUser()->isAllowed( 'bot' ) && $this->bot;
                $status = $this->internalAttemptSave( $resultDetails, $bot );

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

                return $status;
        }

        /**
         * Handle status, such as after attempt save
         *
         * @param Status $status
         * @param array|bool $resultDetails
         *
         * @throws ErrorPageError
         * @return bool False, if output is done, true if rest of the form should be displayed
         */
        private function handleStatus( Status $status, $resultDetails ) {
                /**
                 * @todo FIXME: once the interface for internalAttemptSave() is made
                 *   nicer, this should use the message in $status
                 */
                if ( $status->value == self::AS_SUCCESS_UPDATE
                        || $status->value == self::AS_SUCCESS_NEW_ARTICLE
                ) {
                        $this->didSave = true;
                        if ( !$resultDetails['nullEdit'] ) {
                                $this->setPostEditCookie( $status->value );
                        }
                }

                $out = $this->context->getOutput();

                // "wpExtraQueryRedirect" is a hidden input to modify
                // after save URL and is not used by actual edit form
                $request = $this->context->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:
                                $out->addWikiText( '<div class="error">' . "\n" . $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'] : '';
                                $out->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;
                                        }
                                }

                                $out->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( $this->context->getUser()->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">' ."\n" . $status->getWikiText() .
                                        '</div>';
                                return true;
                }
        }

        /**
         * Run hooks that can filter edits just before they get saved.
         *
         * @param Content $content The Content to filter.
         * @param Status $status For reporting the outcome to the caller
         * @param User $user The user performing the edit
         *
         * @return bool
         */
        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->context, $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;
        }

        /**
         * Return the summary to be used for a new section.
         *
         * @param string $sectionanchor Set to the section anchor text
         * @return string
         */
        private function newSectionSummary( &$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;
        }

        /**
         * Attempt submission (no UI)
         *
         * @param array $result Array to add statuses to, currently with the
         *   possible keys:
         *   - spam (string): Spam string from content if any spam is detected by
         *     matchSpamRegex.
         *   - sectionanchor (string): Section anchor for a section save.
         *   - nullEdit (boolean): Set if doEditContent is OK.  True if null edit,
         *     false otherwise.
         *   - redirect (bool): Set if doEditContent is OK. True if resulting
         *     revision is a redirect.
         * @param bool $bot True if edit is being made under the bot right.
         *
         * @return Status Status object, possibly with a message, but always with
         *   one of the AS_* constants in $status->value,
         *
         * @todo FIXME: This interface is TERRIBLE, but hard to get rid of due to
         *   various error display idiosyncrasies. There are also lots of cases
         *   where error metadata is set in the object and retrieved later instead
         *   of being returned, e.g. AS_CONTENT_TOO_BIG and
         *   AS_BLOCKED_PAGE_FOR_USER. All that stuff needs to be cleaned up some
         * time.
         */
        function internalAttemptSave( &$result, $bot = false ) {
                global $wgParser, $wgMaxArticleSize, $wgContentHandlerUseDB;

                $status = Status::newGood();
                $user = $this->context->getUser();
                $request = $this->context->getRequest();

                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 = $request->getText( 'wpAntispam' );
                if ( $spam !== '' ) {
                        wfDebugLog(
                                'SimpleAntiSpam',
                                $user->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 &&
                        $textbox_content->isRedirect() &&
                        !$user->isAllowed( 'upload' )
                ) {
                                $code = $user->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 = $request->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 ( $user->isBlockedFrom( $this->mTitle, false ) ) {
                        // Auto-block user's IP if the account was "hard" blocked
                        if ( !wfReadOnly() ) {
                                $user->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 ( !$user->isAllowed( 'edit' ) ) {
                        if ( $user->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 $status;
                        } elseif ( !$user->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, $user );
                        if ( !$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 ( $user->pingLimiter() || $user->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', $user ) ) {
                                $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, $user ) ) {
                                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() == $user->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(),
                                                $user->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, $user ) ) {
                                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( $user ) )
                                && !$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,
                        $user,
                        $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
                        $user->pingLimiter( 'linkpurge' );
                }
                $result['redirect'] = $content->isRedirect();

                $this->updateWatchlist();

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

                return $status;
        }

        /**
         * @param User $user
         * @param string|false $oldModel false if the page is being newly created
         * @param string $newModel
         * @param string $reason
         */
        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 );
        }

        /**
         * Register the change of watch status
         */
        protected function updateWatchlist() {
                $user = $this->context->getUser();

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

                $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 );
                } );
        }

        /**
         * Attempts to do 3-way merge of edit content with a base revision
         * and current content, in case of edit conflict, in whichever way appropriate
         * for the content type.
         *
         * @since 1.21
         *
         * @param Content $editContent
         *
         * @return bool
         */
        private function mergeChangesIntoContent( &$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;
        }

        /**
         * @note: this method is very poorly named. If the user opened the form with ?oldid=X,
         *        one might think of X as the "base revision", which is NOT what this returns.
         * @return Revision Current version when the edit was started
         */
        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;
        }

        /**
         * Check given input text against $wgSpamRegex, and return the text of the first match.
         *
         * @param string $text
         *
         * @return string|bool Matching string or false
         */
        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 );
        }

        /**
         * Check given input text against $wgSummarySpamRegex, and return the text of the first match.
         *
         * @param string $text
         *
         * @return string|bool Matching string or false
         */
        public static function matchSummarySpamRegex( $text ) {
                global $wgSummarySpamRegex;
                $regexes = (array)$wgSummarySpamRegex;
                return self::matchSpamRegexInternal( $text, $regexes );
        }

        /**
         * @param string $text
         * @param array $regexes
         * @return bool|string
         */
        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 $wgAjaxEditStash;

                $out = $this->context->getOutput();
                $user = $this->context->getUser();

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

                if ( $user->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).
                        $out->addModules( 'mediawiki.toolbar' );
                }

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

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

                # Enabled article-related sidebar, toplinks, etc.
                $out->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();
                }
                $out->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
                $out->addJsConfigVars( [
                        'wgEditMessage' => $msg,
                        'wgAjaxEditStash' => $wgAjaxEditStash,
                ] );
        }

        /**
         * Show all applicable editing introductions
         */
        protected function showIntro() {
                if ( $this->suppressIntro ) {
                        return;
                }

                $out = $this->context->getOutput();
                $namespace = $this->mTitle->getNamespace();

                if ( $namespace == NS_MEDIAWIKI ) {
                        # Show a warning if editing an interface message
                        $out->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 ) {
                                        $out->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() ) {
                                                $out->wrapWikiMsg( "<div class=\"mw-sharedupload-desc-create\">\n$1\n</div>", [
                                                                        'sharedupload-desc-create', $file->getRepo()->getDisplayName(), $descUrl
                                                ] );
                                        } else {
                                                $out->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
                                $out->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(
                                        $out,
                                        '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 ( $this->context->getUser()->isLoggedIn() ) {
                                $out->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 {
                                $out->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( $out, [ 'delete', 'move' ], $this->mTitle,
                                '',
                                [
                                        'lim' => 10,
                                        'conds' => [ "log_action != 'revision'" ],
                                        'showIfEmpty' => false,
                                        'msgKey' => [ 'recreate-moveddeleted-warn' ]
                                ]
                        );
                }
        }

        /**
         * Attempt to show a custom editing introduction, if supplied
         *
         * @return bool
         */
        protected function showCustomIntro() {
                if ( $this->editintro ) {
                        $title = Title::newFromText( $this->editintro );
                        if ( $title instanceof Title && $title->exists() && $title->userCan( 'read' ) ) {
                                // Added using template syntax, to take <noinclude>'s into account.
                                $this->context->getOutput()->addWikiTextTitleTidy(
                                        '<div class="mw-editintro">{{:' . $title->getFullText() . '}}</div>',
                                        $this->mTitle
                                );
                                return true;
                        }
                }
                return false;
        }

        /**
         * Gets an editable textual representation of $content.
         * The textual representation can be turned by into a Content object by the
         * toEditContent() method.
         *
         * If $content is null or false or a string, $content is returned unchanged.
         *
         * If the given Content object is not of a type that can be edited using
         * the text base EditPage, an exception will be raised. Set
         * $this->allowNonTextContent to true to allow editing of non-textual
         * content.
         *
         * @param Content|null|bool|string $content
         * @return string The editable text form of the content.
         *
         * @throws MWException If $content is not an instance of TextContent and
         *   $this->allowNonTextContent is not true.
         */
        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 );
        }

        /**
         * Turns the given text into a Content object by unserializing it.
         *
         * If the resulting Content object is not of a type that can be edited using
         * the text base EditPage, an exception will be raised. Set
         * $this->allowNonTextContent to true to allow editing of non-textual
         * content.
         *
         * @param string|null|bool $text Text to unserialize
         * @return Content|bool|null The content object created from $text. If $text was false
         *   or null, false resp. null will be  returned instead.
         *
         * @throws MWException If unserializing the text results in a Content
         *   object that is not an instance of TextContent and
         *   $this->allowNonTextContent is not true.
         */
        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;
        }

        /**
         * Send the edit form and related headers to $wgOut
         * @param callable|null $formCallback That takes an OutputPage parameter; will be called
         *     during form output near the top, for captchas and the like.
         *
         * The $formCallback parameter is deprecated since MediaWiki 1.25. Please
         * use the EditPage::showEditForm:fields hook instead.
         */
        function showEditForm( $formCallback = null ) {
                # 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();
                }

                $out = $this->context->getOutput();
                Hooks::run( 'EditPage::showEditForm:initial', [ &$this, &$out ] );

                $this->setHeaders();

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

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

                $user = $this->context->getUser();
                if ( $user->getOption( 'previewontop' ) ) {
                        $this->displayPreviewArea( $previewOutput, true );
                }

                $out->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 {
                                $out->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.
                $out->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( $formCallback, [ &$out ] );
                }

                // Add an empty field to trip up spambots
                $out->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', [ &$this, &$out ] );

                // 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';
                        $out->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 ) {
                        $out->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 ) ) {
                        $out->addHTML( Html::hidden( 'wpIgnoreBlankSummary', true ) );
                }

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

                if ( $this->selfRedirect ) {
                        $out->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 );
                $out->addHTML( Html::hidden( 'wpAutoSummary', $autosumm ) );

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

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

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

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

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

                if ( $this->blankArticle ) {
                        $out->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();
                }

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

                $this->showStandardInputs();

                $this->showFormAfterText();

                $this->showTosSummary();

                $this->showEditTools();

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

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

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

                if ( $this->mParserOutput ) {
                        $out->setLimitReportData( $this->mParserOutput->getLimitReportData() );
                }

                $out->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()
                                );
                                $out->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';
                }
                $out->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.
                $out->addHTML( Html::hidden( 'wpUltimateParam', true ) );
                $out->addHTML( $this->editFormTextBottom . "\n</form>\n" );

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

        }

        /**
         * Extract the section title from current section text, if any.
         *
         * @param string $text
         * @return string|bool String or 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;
                }
        }

        /**
         * @return bool
         */
        protected function showHeader() {
                global $wgMaxArticleSize, $wgAllowUserCss, $wgAllowUserJs;

                $out = $this->context->getOutput();
                $user = $this->context->getUser();

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

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

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

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

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

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

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

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

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

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

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

                if ( wfReadOnly() ) {
                        $out->wrapWikiMsg(
                                "<div id=\"mw-read-only-warning\">\n$1\n</div>",
                                [ 'readonlywarning', wfReadOnlyReason() ]
                        );
                } elseif ( $user->isAnon() ) {
                        if ( $this->formtype != 'preview' ) {
                                $out->wrapWikiMsg(
                                        "<div id='mw-anon-edit-warning' class='warningbox'>\n$1\n</div>",
                                        [ 'anoneditwarning',
                                                // Log-in link
                                                SpecialPage::getTitleFor( 'Userlogin' )->getFullURL( [
                                                        'returnto' => $this->getTitle()->getPrefixedDBkey()
                                                ] ),
                                                // Sign-up link
                                                SpecialPage::getTitleFor( 'CreateAccount' )->getFullURL( [
                                                        'returnto' => $this->getTitle()->getPrefixedDBkey()
                                                ] )
                                        ]
                                );
                        } else {
                                $out->wrapWikiMsg( "<div id=\"mw-anon-preview-warning\" class=\"warningbox\">\n$1</div>",
                                        'anonpreviewwarning'
                                );
                        }
                } else {
                        if ( $this->isCssJsSubpage ) {
                                # Check the skin exists
                                if ( $this->isWrongCaseCssJsPage ) {
                                        $out->wrapWikiMsg(
                                                "<div class='error' id='mw-userinvalidcssjstitle'>\n$1\n</div>",
                                                [ 'userinvalidcssjstitle', $this->mTitle->getSkinFromCssJsSubpage() ]
                                        );
                                }
                                if ( $this->getTitle()->isSubpageOf( $user->getUserPage() ) ) {
                                        $out->wrapWikiMsg( '<div class="mw-usercssjspublic">$1</div>',
                                                $this->isCssSubpage ? 'usercssispublic' : 'userjsispublic'
                                        );
                                        if ( $this->formtype !== 'preview' ) {
                                                if ( $this->isCssSubpage && $wgAllowUserCss ) {
                                                        $out->wrapWikiMsg(
                                                                "<div id='mw-usercssyoucanpreview'>\n$1\n</div>",
                                                                [ 'usercssyoucanpreview' ]
                                                        );
                                                }

                                                if ( $this->isJsSubpage && $wgAllowUserJs ) {
                                                        $out->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( $out, 'protect', $this->mTitle, '',
                                [ 'lim' => 1, 'msgKey' => [ $noticeMsg ] ] );
                }
                if ( $this->mTitle->isCascadeProtected() ) {
                        # Is this page under cascading protection from some source pages?
                        /** @var Title[] $cascadeSources */
                        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>';
                        $out->wrapWikiMsg( $notice, [ 'cascadeprotectedwarning', $cascadeSourcesCount ] );
                }
                if ( !$this->mTitle->exists() && $this->mTitle->getRestrictions( 'create' ) ) {
                        LogEventsList::showLogExtract( $out, '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 );
                }

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

                return true;
        }

        /**
         * Standard summary input and label (wgSummary), abstracted so EditPage
         * subclasses may reorganize the form.
         * Note that you do not need to worry about the label's for=, it will be
         * inferred by the id given to the input. You can remove them both by
         * passing array( 'id' => false ) to $userInputAttrs.
         *
         * @param string $summary The value of the summary input
         * @param string $labelText The html to place inside the label
         * @param array $inputAttrs Array of attrs to use on the input
         * @param array $spanLabelAttrs Array of attrs to use on the span inside the label
         *
         * @return array An array in the format array( $label, $input )
         */
        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 ];
        }

        /**
         * @param bool $isSubjectPreview True if this is the section subject/title
         *   up top, or false if this is the comment summary
         *   down below the textarea
         * @param string $summary The text of the summary to display
         */
        protected function showSummaryInput( $isSubjectPreview, $summary = "" ) {
                # 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 ],
                        []
                );
                $this->context->getOutput()->addHTML( "{$label} {$input}" );
        }

        /**
         * @param bool $isSubjectPreview True if this is the section subject/title
         *   up top, or false if this is the comment summary
         *   down below the textarea
         * @param string $summary The text of the summary to display
         * @return string
         */
        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() {
                $section = htmlspecialchars( $this->section );
                $out = $this->context->getOutput();
                $out->addHTML( <<<HTML
<input type='hidden' value="{$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() ) {
                        $out->addHTML( Html::hidden( 'safemode', '1' ) );
                }
        }

        protected function showFormAfterText() {
                /**
                 * To make it harder for someone to slip a user a page
                 * which submits an edit form to the wiki without their
                 * knowledge, a random token is associated with the login
                 * session. If it's not passed back with the submission,
                 * we won't save the page, or render user JavaScript and
                 * CSS previews.
                 *
                 * For anon editors, who may not have a session, we just
                 * include the constant suffix to prevent editing from
                 * broken text-mangling proxies.
                 */
                $token = $this->context->getUser()->getEditToken();
                $this->context->getOutput()->addHTML(
                        "\n" . Html::hidden( "wpEditToken", $token ) . "\n"
                );
        }

        /**
         * Subpage overridable method for printing the form for page content editing
         * By default this simply outputs wpTextbox1
         * Subclasses can override this to provide a custom UI for editing;
         * be it a form, or simply wpTextbox1 with a modified content that will be
         * reverse modified when extracted from the post data.
         * Note that this is basically the inverse for importContentFormData
         */
        protected function showContentForm() {
                $this->showTextbox1();
        }

        /**
         * Method to output wpTextbox1
         * The $textoverride method can be used by subclasses overriding showContentForm
         * to pass back to this method.
         *
         * @param array $customAttribs Array of html attributes to use in the textarea
         * @param string $textoverride Optional text to override $this->textarea1 with
         */
        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 = [] ) {
                $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";
                }

                $user = $this->context->getUser();
                $attribs = $customAttribs + [
                        'accesskey' => ',',
                        'id' => $name,
                        'cols' => $user->getIntOption( 'cols' ),
                        'rows' => $user->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();

                $this->context->getOutput()->addHTML( Html::textarea( $name, $wikitext, $attribs ) );
        }

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

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

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

                $out = $this->context->getOutput();
                $out->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() ];
                        $out->addHTML( Html::rawElement( 'div', $attribs ) );
                }

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

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

        /**
         * Append preview output to $wgOut.
         * Includes category rendering if this is a category page.
         *
         * @param string $text The HTML to be output for the preview.
         */
        protected function showPreview( $text ) {
                if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
                        $this->mArticle->openShowCategory();
                }
                $out = $this->context->getOutput();
                # This hook seems slightly odd here, but makes things more
                # consistent for extensions.
                Hooks::run( 'OutputPageBeforeHTML', [ &$out, &$text ] );
                $out->addHTML( $text );
                if ( $this->mTitle->getNamespace() == NS_CATEGORY ) {
                        $this->mArticle->closeShowCategory();
                }
        }

        /**
         * Get a diff between the current contents of the edit box and the
         * version of the page we're editing from.
         *
         * If this is a section edit, we'll replace the section as for final
         * save and then make a comparison.
         */
        function showDiff() {
                global $wgContLang;

                $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 ] );

                        $user = $this->context->getUser();
                        $popts = ParserOptions::newFromUserAndLang( $user, $wgContLang );
                        $newContent = $newContent->preSaveTransform( $this->mTitle, $user, $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 = '';
                }

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

        /**
         * Show the header copyright warning.
         */
        protected function showHeaderCopyrightWarning() {
                $msg = 'editpage-head-copy-warn';
                if ( !wfMessage( $msg )->isDisabled() ) {
                        $this->context->getOutput()->wrapWikiMsg( "<div class='editpage-head-copywarn'>\n$1\n</div>",
                                'editpage-head-copy-warn' );
                }
        }

        /**
         * Give a chance for site and per-namespace customizations of
         * terms of service summary link that might exist separately
         * from the copyright notice.
         *
         * This will display between the save button and the edit tools,
         * so should remain short!
         */
        protected function showTosSummary() {
                $msg = 'editpage-tos-summary';
                Hooks::run( 'EditPageTosSummary', [ $this->mTitle, &$msg ] );
                if ( !wfMessage( $msg )->isDisabled() ) {
                        $out = $this->context->getOutput();
                        $out->addHTML( '<div class="mw-tos-summary">' );
                        $out->addWikiMsg( $msg );
                        $out->addHTML( '</div>' );
                }
        }

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

        /**
         * Get the copyright warning
         *
         * Renamed to getCopyrightWarning(), old name kept around for backwards compatibility
         * @return string
         */
        protected function getCopywarn() {
                return self::getCopyrightWarning( $this->mTitle );
        }

        /**
         * Get the copyright warning, by default returns wikitext
         *
         * @param Title $title
         * @param string $format Output format, valid values are any function of a Message object
         * @return string
         */
        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>";
        }

        /**
         * Get the Limit report for page previews
         *
         * @since 1.22
         * @param ParserOutput $output ParserOutput object from the parse
         * @return string HTML
         */
        public static function getPreviewLimitReport( $output ) {
                if ( !$output || !$output->getLimitReportData() ) {
                        return '';
                }

                return ResourceLoader::makeInlineScript(
                        ResourceLoader::makeConfigSetScript(
                                [ 'wgPageParseReport' => $output->getLimitReportData() ],
                                true
                        )
                );
        }

        protected function showStandardInputs( &$tabindex = 2 ) {
                $out = $this->context->getOutput();
                $out->addHTML( "<div class='editOptions'>\n" );

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

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

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

                $out->addHTML( "<div class='editButtons'>\n" );
                $out->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();

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

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

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

        /**
         * Show an edit conflict. textbox1 is already shown in showEditForm().
         * If you want to use another entry point to this function, be careful.
         */
        protected function showConflict() {
                $out = $this->context->getOutput();
                if ( Hooks::run( 'EditPageBeforeConflictDiff', [ &$this, &$out ] ) ) {
                        $stats = $this->context->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() );
                        }

                        $out->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()
                        );

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

        /**
         * @return string
         */
        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
                );
        }

        /**
         * Returns the URL to use in the form's action attribute.
         * This is used by EditPage subclasses when simply customizing the action
         * variable in the constructor is not enough. This can be used when the
         * EditPage lives inside of a Special page rather than a custom page action.
         *
         * @param Title $title Title object for which is being edited (where we go to for &action= links)
         * @return string
         */
        protected function getActionURL( Title $title ) {
                return $title->getLocalURL( [ 'action' => $this->action ] );
        }

        /**
         * Check if a page was deleted while the user was editing it, before submit.
         * Note that we rely on the logging table, which hasn't been always there,
         * but that doesn't matter, because this only applies to brand new
         * deletes.
         * @return bool
         */
        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;
        }

        /**
         * @return bool|stdClass
         */
        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;
        }

        /**
         * Get the rendered text for previewing.
         * @throws MWException
         * @return string
         */
        function getPreviewText() {
                global $wgRawHtml, $wgAllowUserCss, $wgAllowUserJs;

                $stats = $this->context->getStats();
                $out = $this->context->getOutput();

                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 = $out->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 . '|' . $this->context->getLanguage()->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;
                        $out->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>" .
                        $out->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;
        }

        /**
         * Get parser options for a preview
         * @return ParserOptions
         */
        protected function getPreviewParserOptions() {
                $parserOptions = $this->page->makeParserOptions( $this->context );
                $parserOptions->setIsPreview( true );
                $parserOptions->setIsSectionPreview( !is_null( $this->section ) && $this->section !== '' );
                $parserOptions->enableLimitReport();
                return $parserOptions;
        }

        /**
         * Parse the page for a preview. Subclasses may override this class, in order
         * to parse with different options, or to otherwise modify the preview HTML.
         *
         * @param Content $content The page content
         * @return array with keys:
         *   - parserOutput: The ParserOutput object
         *   - html: The HTML to be displayed
         */
        protected function doPreviewParse( Content $content ) {
                $user = $this->context->getUser();
                $parserOptions = $this->getPreviewParserOptions();
                $pstContent = $content->preSaveTransform( $this->mTitle, $user, $parserOptions );
                $scopedCallback = $parserOptions->setupFakeRevision(
                        $this->mTitle, $pstContent, $user );
                $parserOutput = $pstContent->getParserOutput( $this->mTitle, null, $parserOptions );
                ScopedCallback::consume( $scopedCallback );
                $parserOutput->setEditSectionTokens( false ); // no section edit links
                return [
                        'parserOutput' => $parserOutput,
                        'html' => $parserOutput->getText() ];
        }

        /**
         * @return array
         */
        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();
                }
        }

        /**
         * Shows a bulletin board style toolbar for common editing functions.
         * It can be disabled in the user preferences.
         *
         * @param Title $title Title object for the page being edited (optional)
         * @return string
         */
        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 is an array of arrays each of which includes the
                 * opening tag, the closing tag, optionally a sample text that is
                 * inserted between the two when no selection is highlighted
                 * and.  The tip text is shown when the user moves the mouse
                 * over the button.
                 *
                 * Images are defined in ResourceLoaderEditToolbarModule.
                 */
                $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;
        }

        /**
         * Returns an array of html code of the following checkboxes:
         * minor and watch
         *
         * @param int $tabindex Current tabindex
         * @param array $checked Array of checkbox => bool, where bool indicates the checked
         *                 status of the checkbox
         *
         * @return array
         */
        public function getCheckboxes( &$tabindex, $checked ) {
                global $wgUseMediaWikiUIEverywhere;

                $checkboxes = [];
                $user = $this->context->getUser();

                // 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 ( $user->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 ( $user->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;
        }

        /**
         * Returns an array of html code of the following buttons:
         * save, diff, preview and live
         *
         * @param int $tabindex Current tabindex
         *
         * @return array
         */
        public function getEditButtons( &$tabindex ) {
                $buttons = [];

                $labelAsPublish = $this->mArticle->getContext()->getConfig()->get( 'EditButtonPublishNotSave' );
                if ( $labelAsPublish ) {
                        $buttonLabelKey = $this->isNew ? 'publishpage' : 'publishchanges';
                } else {
                        $buttonLabelKey = $this->isNew ? 'savearticle' : 'savechanges';
                }
                $buttonLabel = wfMessage( $buttonLabelKey )->text();
                $attribs = [
                        'id' => 'wpSave',
                        'name' => 'wpSave',
                        'tabindex' => ++$tabindex,
                ] + Linker::tooltipAndAccesskeyAttribs( 'save' );
                $buttons['save'] = Html::submitButton( $buttonLabel, $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;
        }

        /**
         * Creates a basic error page which informs the user that
         * they have attempted to edit a nonexistent section.
         */
        function noSuchSectionPage() {
                $out = $this->context->getOutput();
                $out->prepareErrorPage( wfMessage( 'nosuchsectiontitle' ) );

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

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

        /**
         * Show "your edit contains spam" page with your diff and text
         *
         * @param string|array|bool $match Text (or array of texts) which triggered one or more filters
         */
        public function spamPageWithContent( $match = false ) {
                $this->textbox2 = $this->textbox1;

                if ( is_array( $match ) ) {
                        $match = $this->context->getLanguage()->listToText( $match );
                }
                $out = $this->context->getOutput();
                $out->prepareErrorPage( wfMessage( 'spamprotectiontitle' ) );

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

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

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

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

        /**
         * Check if the browser is on a blacklist of user-agents known to
         * mangle UTF-8 data on form submission. Returns true if Unicode
         * should make it through, false if it's known to be a problem.
         * @return bool
         */
        private function checkUnicodeCompliantBrowser() {
                global $wgBrowserBlackList;

                $currentbrowser = $this->context->getRequest()->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;
        }

        /**
         * Filter an input field through a Unicode de-armoring process if it
         * came from an old browser with known broken Unicode editing issues.
         *
         * @param WebRequest $request
         * @param string $field
         * @return string
         */
        protected function safeUnicodeInput( $request, $field ) {
                $text = rtrim( $request->getText( $field ) );
                return $request->getBool( 'safemode' )
                        ? $this->unmakeSafe( $text )
                        : $text;
        }

        /**
         * Filter an output field through a Unicode armoring process if it is
         * going to an old browser with known broken Unicode editing issues.
         *
         * @param string $text
         * @return string
         */
        protected function safeUnicodeOutput( $text ) {
                return $this->checkUnicodeCompliantBrowser()
                        ? $text
                        : $this->makesafe( $text );
        }

        /**
         * A number of web browsers are known to corrupt non-ASCII characters
         * in a UTF-8 text editing environment. To protect against this,
         * detected browsers will be served an armored version of the text,
         * with non-ASCII chars converted to numeric HTML character references.
         *
         * Preexisting such character references will have a 0 added to them
         * to ensure that round-trips do not alter the original data.
         *
         * @param string $invalue
         * @return string
         */
        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;
        }

        /**
         * Reverse the previously applied transliteration of non-ASCII characters
         * back to UTF-8. Used to protect data from corruption by broken web browsers
         * as listed in $wgBrowserBlackList.
         *
         * @param string $invalue
         * @return string
         */
        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" ] );
        }
}