ContentHandler.php

Go to the documentation of this file.

<?php

class MWContentSerializationException extends MWException {

}

abstract class ContentHandler {

        protected static $enableDeprecationWarnings = false;

        public static function getContentText( Content $content = null ) {
                global $wgContentHandlerTextFallback;

                if ( is_null( $content ) ) {
                        return '';
                }

                if ( $content instanceof TextContent ) {
                        return $content->getNativeData();
                }

                wfDebugLog( 'ContentHandler', 'Accessing ' . $content->getModel() . ' content as text!' );

                if ( $wgContentHandlerTextFallback == 'fail' ) {
                        throw new MWException(
                                "Attempt to get text from Content with model " .
                                $content->getModel()
                        );
                }

                if ( $wgContentHandlerTextFallback == 'serialize' ) {
                        return $content->serialize();
                }

                return null;
        }

        public static function makeContent( $text, Title $title = null,
                $modelId = null, $format = null )
        {
                if ( is_null( $modelId ) ) {
                        if ( is_null( $title ) ) {
                                throw new MWException( "Must provide a Title object or a content model ID." );
                        }

                        $modelId = $title->getContentModel();
                }

                $handler = ContentHandler::getForModelID( $modelId );
                return $handler->unserializeContent( $text, $format );
        }

        public static function getDefaultModelFor( Title $title ) {
                global $wgNamespaceContentModels;

                // NOTE: this method must not rely on $title->getContentModel() directly or indirectly,
                //       because it is used to initialize the mContentModel member.

                $ns = $title->getNamespace();

                $ext = false;
                $m = null;
                $model = null;

                if ( !empty( $wgNamespaceContentModels[ $ns ] ) ) {
                        $model = $wgNamespaceContentModels[ $ns ];
                }

                // Hook can determine default model
                if ( !wfRunHooks( 'ContentHandlerDefaultModelFor', array( $title, &$model ) ) ) {
                        if ( !is_null( $model ) ) {
                                return $model;
                        }
                }

                // Could this page contain custom CSS or JavaScript, based on the title?
                $isCssOrJsPage = NS_MEDIAWIKI == $ns && preg_match( '!\.(css|js)$!u', $title->getText(), $m );
                if ( $isCssOrJsPage ) {
                        $ext = $m[1];
                }

                // Hook can force JS/CSS
                wfRunHooks( 'TitleIsCssOrJsPage', array( $title, &$isCssOrJsPage ) );

                // Is this a .css subpage of a user page?
                $isJsCssSubpage = NS_USER == $ns
                        && !$isCssOrJsPage
                        && preg_match( "/\\/.*\\.(js|css)$/", $title->getText(), $m );
                if ( $isJsCssSubpage ) {
                        $ext = $m[1];
                }

                // Is this wikitext, according to $wgNamespaceContentModels or the DefaultModelFor hook?
                $isWikitext = is_null( $model ) || $model == CONTENT_MODEL_WIKITEXT;
                $isWikitext = $isWikitext && !$isCssOrJsPage && !$isJsCssSubpage;

                // Hook can override $isWikitext
                wfRunHooks( 'TitleIsWikitextPage', array( $title, &$isWikitext ) );

                if ( !$isWikitext ) {
                        switch ( $ext ) {
                                case 'js':
                                        return CONTENT_MODEL_JAVASCRIPT;
                                case 'css':
                                        return CONTENT_MODEL_CSS;
                                default:
                                        return is_null( $model ) ? CONTENT_MODEL_TEXT : $model;
                        }
                }

                // We established that it must be wikitext

                return CONTENT_MODEL_WIKITEXT;
        }

        public static function getForTitle( Title $title ) {
                $modelId = $title->getContentModel();
                return ContentHandler::getForModelID( $modelId );
        }

        public static function getForContent( Content $content ) {
                $modelId = $content->getModel();
                return ContentHandler::getForModelID( $modelId );
        }

        static $handlers;

        public static function getForModelID( $modelId ) {
                global $wgContentHandlers;

                if ( isset( ContentHandler::$handlers[$modelId] ) ) {
                        return ContentHandler::$handlers[$modelId];
                }

                if ( empty( $wgContentHandlers[$modelId] ) ) {
                        $handler = null;

                        wfRunHooks( 'ContentHandlerForModelID', array( $modelId, &$handler ) );

                        if ( $handler === null ) {
                                throw new MWException( "No handler for model '$modelId'' registered in \$wgContentHandlers" );
                        }

                        if ( !( $handler instanceof ContentHandler ) ) {
                                throw new MWException( "ContentHandlerForModelID must supply a ContentHandler instance" );
                        }
                } else {
                        $class = $wgContentHandlers[$modelId];
                        $handler = new $class( $modelId );

                        if ( !( $handler instanceof ContentHandler ) ) {
                                throw new MWException( "$class from \$wgContentHandlers is not compatible with ContentHandler" );
                        }
                }

                wfDebugLog( 'ContentHandler', 'Created handler for ' . $modelId
                                        . ': ' . get_class( $handler ) );

                ContentHandler::$handlers[$modelId] = $handler;
                return ContentHandler::$handlers[$modelId];
        }

        public static function getLocalizedName( $name ) {
                $key = "content-model-$name";

                $msg = wfMessage( $key );

                return $msg->exists() ? $msg->plain() : $name;
        }

        public static function getContentModels() {
                global $wgContentHandlers;

                return array_keys( $wgContentHandlers );
        }

        public static function getAllContentFormats() {
                global $wgContentHandlers;

                $formats = array();

                foreach ( $wgContentHandlers as $model => $class ) {
                        $handler = ContentHandler::getForModelID( $model );
                        $formats = array_merge( $formats, $handler->getSupportedFormats() );
                }

                $formats = array_unique( $formats );
                return $formats;
        }

        // ------------------------------------------------------------------------

        protected $mModelID;
        protected $mSupportedFormats;

        public function __construct( $modelId, $formats ) {
                $this->mModelID = $modelId;
                $this->mSupportedFormats = $formats;

                $this->mModelName = preg_replace( '/(Content)?Handler$/', '', get_class( $this ) );
                $this->mModelName = preg_replace( '/[_\\\\]/', '', $this->mModelName );
                $this->mModelName = strtolower( $this->mModelName );
        }

        public abstract function serializeContent( Content $content, $format = null );

        public abstract function unserializeContent( $blob, $format = null );

        public abstract function makeEmptyContent();

        public function makeRedirectContent( Title $destination ) {
                return null;
        }

        public function getModelID() {
                return $this->mModelID;
        }

        protected function checkModelID( $model_id ) {
                if ( $model_id !== $this->mModelID ) {
                        throw new MWException( "Bad content model: " .
                                "expected {$this->mModelID} " .
                                "but got $model_id." );
                }
        }

        public function getSupportedFormats() {
                return $this->mSupportedFormats;
        }

        public function getDefaultFormat() {
                return $this->mSupportedFormats[0];
        }

        public function isSupportedFormat( $format ) {

                if ( !$format ) {
                        return true; // this means "use the default"
                }

                return in_array( $format, $this->mSupportedFormats );
        }

        protected function checkFormat( $format ) {
                if ( !$this->isSupportedFormat( $format ) ) {
                        throw new MWException(
                                "Format $format is not supported for content model "
                                . $this->getModelID()
                        );
                }
        }

        public function getActionOverrides() {
                return array();
        }

        public function createDifferenceEngine( IContextSource $context,
                $old = 0, $new = 0,
                $rcid = 0, # FIXME: use everywhere!
                $refreshCache = false, $unhide = false
        ) {
                $diffEngineClass = $this->getDiffEngineClass();

                return new $diffEngineClass( $context, $old, $new, $rcid, $refreshCache, $unhide );
        }

        public function getPageLanguage( Title $title, Content $content = null ) {
                global $wgContLang, $wgLang;
                $pageLang = $wgContLang;

                if ( $title->getNamespace() == NS_MEDIAWIKI ) {
                        // Parse mediawiki messages with correct target language
                        list( /* $unused */, $lang ) = MessageCache::singleton()->figureMessage( $title->getText() );
                        $pageLang = wfGetLangObj( $lang );
                }

                wfRunHooks( 'PageContentLanguage', array( $title, &$pageLang, $wgLang ) );
                return wfGetLangObj( $pageLang );
        }

        public function getPageViewLanguage( Title $title, Content $content = null ) {
                $pageLang = $this->getPageLanguage( $title, $content );

                if ( $title->getNamespace() !== NS_MEDIAWIKI ) {
                        // If the user chooses a variant, the content is actually
                        // in a language whose code is the variant code.
                        $variant = $pageLang->getPreferredVariant();
                        if ( $pageLang->getCode() !== $variant ) {
                                $pageLang = Language::factory( $variant );
                        }
                }

                return $pageLang;
        }

        public function canBeUsedOn( Title $title ) {
                return true;
        }

        protected function getDiffEngineClass() {
                return 'DifferenceEngine';
        }

        public function merge3( Content $oldContent, Content $myContent, Content $yourContent ) {
                return false;
        }

        public function getAutosummary( Content $oldContent = null, Content $newContent = null, $flags ) {
                global $wgContLang;

                // Decide what kind of auto-summary is needed.

                // Redirect auto-summaries

                $ot = !is_null( $oldContent ) ? $oldContent->getRedirectTarget() : null;
                $rt = !is_null( $newContent ) ? $newContent->getRedirectTarget() : null;

                if ( is_object( $rt ) ) {
                        if ( !is_object( $ot )
                                || !$rt->equals( $ot )
                                || $ot->getFragment() != $rt->getFragment() )
                        {
                                $truncatedtext = $newContent->getTextForSummary(
                                        250
                                                - strlen( wfMessage( 'autoredircomment' )->inContentLanguage()->text() )
                                                - strlen( $rt->getFullText() ) );

                                return wfMessage( 'autoredircomment', $rt->getFullText() )
                                                ->rawParams( $truncatedtext )->inContentLanguage()->text();
                        }
                }

                // New page auto-summaries
                if ( $flags & EDIT_NEW && $newContent->getSize() > 0 ) {
                        // If they're making a new article, give its text, truncated, in
                        // the summary.

                        $truncatedtext = $newContent->getTextForSummary(
                                200 - strlen( wfMessage( 'autosumm-new' )->inContentLanguage()->text() ) );

                        return wfMessage( 'autosumm-new' )->rawParams( $truncatedtext )
                                        ->inContentLanguage()->text();
                }

                // Blanking auto-summaries
                if ( !empty( $oldContent ) && $oldContent->getSize() > 0 && $newContent->getSize() == 0 ) {
                        return wfMessage( 'autosumm-blank' )->inContentLanguage()->text();
                } elseif ( !empty( $oldContent )
                        && $oldContent->getSize() > 10 * $newContent->getSize()
                        && $newContent->getSize() < 500 )
                {
                        // Removing more than 90% of the article

                        $truncatedtext = $newContent->getTextForSummary(
                                200 - strlen( wfMessage( 'autosumm-replace' )->inContentLanguage()->text() ) );

                        return wfMessage( 'autosumm-replace' )->rawParams( $truncatedtext )
                                        ->inContentLanguage()->text();
                }

                // If we reach this point, there's no applicable auto-summary for our
                // case, so our auto-summary is empty.
                return '';
        }

        public function getAutoDeleteReason( Title $title, &$hasHistory ) {
                $dbw = wfGetDB( DB_MASTER );

                // Get the last revision
                $rev = Revision::newFromTitle( $title );

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

                // Get the article's contents
                $content = $rev->getContent();
                $blank = false;

                // If the page is blank, use the text from the previous revision,
                // which can only be blank if there's a move/import/protect dummy
                // revision involved
                if ( !$content || $content->isEmpty() ) {
                        $prev = $rev->getPrevious();

                        if ( $prev ) {
                                $rev = $prev;
                                $content = $rev->getContent();
                                $blank = true;
                        }
                }

                $this->checkModelID( $rev->getContentModel() );

                // Find out if there was only one contributor
                // Only scan the last 20 revisions
                $res = $dbw->select( 'revision', 'rev_user_text',
                        array(
                                'rev_page' => $title->getArticleID(),
                                $dbw->bitAnd( 'rev_deleted', Revision::DELETED_USER ) . ' = 0'
                        ),
                        __METHOD__,
                        array( 'LIMIT' => 20 )
                );

                if ( $res === false ) {
                        // This page has no revisions, which is very weird
                        return false;
                }

                $hasHistory = ( $res->numRows() > 1 );
                $row = $dbw->fetchObject( $res );

                if ( $row ) { // $row is false if the only contributor is hidden
                        $onlyAuthor = $row->rev_user_text;
                        // Try to find a second contributor
                        foreach ( $res as $row ) {
                                if ( $row->rev_user_text != $onlyAuthor ) { // Bug 22999
                                        $onlyAuthor = false;
                                        break;
                                }
                        }
                } else {
                        $onlyAuthor = false;
                }

                // Generate the summary with a '$1' placeholder
                if ( $blank ) {
                        // The current revision is blank and the one before is also
                        // blank. It's just not our lucky day
                        $reason = wfMessage( 'exbeforeblank', '$1' )->inContentLanguage()->text();
                } else {
                        if ( $onlyAuthor ) {
                                $reason = wfMessage(
                                        'excontentauthor',
                                        '$1',
                                        $onlyAuthor
                                )->inContentLanguage()->text();
                        } else {
                                $reason = wfMessage( 'excontent', '$1' )->inContentLanguage()->text();
                        }
                }

                if ( $reason == '-' ) {
                        // Allow these UI messages to be blanked out cleanly
                        return '';
                }

                // Max content length = max comment length - length of the comment (excl. $1)
                $text = $content ? $content->getTextForSummary( 255 - ( strlen( $reason ) - 2 ) ) : '';

                // Now replace the '$1' placeholder
                $reason = str_replace( '$1', $text, $reason );

                return $reason;
        }

        public function getUndoContent( Revision $current, Revision $undo, Revision $undoafter ) {
                $cur_content = $current->getContent();

                if ( empty( $cur_content ) ) {
                        return false; // no page
                }

                $undo_content = $undo->getContent();
                $undoafter_content = $undoafter->getContent();

                $this->checkModelID( $cur_content->getModel() );
                $this->checkModelID( $undo_content->getModel() );
                $this->checkModelID( $undoafter_content->getModel() );

                if ( $cur_content->equals( $undo_content ) ) {
                        // No use doing a merge if it's just a straight revert.
                        return $undoafter_content;
                }

                $undone_content = $this->merge3( $undo_content, $undoafter_content, $cur_content );

                return $undone_content;
        }

        public function makeParserOptions( $context ) {
                global $wgContLang;

                if ( $context instanceof IContextSource ) {
                        $options = ParserOptions::newFromContext( $context );
                } elseif ( $context instanceof User ) { // settings per user (even anons)
                        $options = ParserOptions::newFromUser( $context );
                } elseif ( $context === 'canonical' ) { // canonical settings
                        $options = ParserOptions::newFromUserAndLang( new User, $wgContLang );
                } else {
                        throw new MWException( "Bad context for parser options: $context" );
                }

                $options->enableLimitReport(); // show inclusion/loop reports
                $options->setTidy( true ); // fix bad HTML

                return $options;
        }

        public function isParserCacheSupported() {
                return false;
        }

        public function supportsSections() {
                return false;
        }

        public static function deprecated( $func, $version, $component = false ) {
                if ( self::$enableDeprecationWarnings ) {
                        wfDeprecated( $func, $version, $component, 3 );
                }
        }

        public static function runLegacyHooks( $event, $args = array(),
                        $warn = null ) {

                if ( $warn === null ) {
                        $warn = self::$enableDeprecationWarnings;
                }

                if ( !Hooks::isRegistered( $event ) ) {
                        return true; // nothing to do here
                }

                if ( $warn ) {
                        // Log information about which handlers are registered for the legacy hook,
                        // so we can find and fix them.

                        $handlers = Hooks::getHandlers( $event );
                        $handlerInfo = array();

                        wfSuppressWarnings();

                        foreach ( $handlers as $handler ) {
                                $info = '';

                                if ( is_array( $handler ) ) {
                                        if ( is_object( $handler[0] ) ) {
                                                $info = get_class( $handler[0] );
                                        } else {
                                                $info = $handler[0];
                                        }

                                        if ( isset( $handler[1] ) ) {
                                                $info .= '::' . $handler[1];
                                        }
                                } else if ( is_object( $handler ) ) {
                                        $info = get_class( $handler[0] );
                                        $info .= '::on' . $event;
                                } else {
                                        $info = $handler;
                                }

                                $handlerInfo[] = $info;
                        }

                        wfRestoreWarnings();

                        wfWarn( "Using obsolete hook $event via ContentHandler::runLegacyHooks()! Handlers: " . implode(', ', $handlerInfo), 2 );
                }

                // convert Content objects to text
                $contentObjects = array();
                $contentTexts = array();

                foreach ( $args as $k => $v ) {
                        if ( $v instanceof Content ) {
                                /* @var Content $v */

                                $contentObjects[$k] = $v;

                                $v = $v->serialize();
                                $contentTexts[ $k ] = $v;
                                $args[ $k ] = $v;
                        }
                }

                // call the hook functions
                $ok = wfRunHooks( $event, $args );

                // see if the hook changed the text
                foreach ( $contentTexts as $k => $orig ) {
                        /* @var Content $content */

                        $modified = $args[ $k ];
                        $content = $contentObjects[$k];

                        if ( $modified !== $orig ) {
                                // text was changed, create updated Content object
                                $content = $content->getContentHandler()->unserializeContent( $modified );
                        }

                        $args[ $k ] = $content;
                }

                return $ok;
        }
}