Remove most named character references from output
[lhc/web/wiklou.git] / includes / diff / DifferenceEngine.php
index 0f03058..3364531 100644 (file)
  * @defgroup DifferenceEngine DifferenceEngine
  */
 
-/**
- * Constant to indicate diff cache compatibility.
- * Bump this when changing the diff formatting in a way that
- * fixes important bugs or such to force cached diff views to
- * clear.
- */
-define( 'MW_DIFF_VERSION', '1.11a' );
-
-/**
- * @todo document
- * @ingroup DifferenceEngine
- */
-class DifferenceEngine {
-       /**#@+
-        * @private
-        */
-       var $mOldid, $mNewid, $mTitle;
-       var $mOldtitle, $mNewtitle, $mPagetitle;
-       var $mOldtext, $mNewtext;
-       var $mOldPage, $mNewPage;
-       var $mRcidMarkPatrolled;
-       var $mOldRev, $mNewRev;
-       var $mRevisionsLoaded = false; // Have the revisions been loaded
-       var $mTextLoaded = 0; // How many text blobs have been loaded, 0, 1 or 2?
-       var $htmldiff;
-       /**#@-*/
-
-       /**
-        * Constructor
-        * @param $titleObj Title object that the diff is associated with
-        * @param $old Integer: old ID we want to show and diff with.
-        * @param $new String: either 'prev' or 'next'.
-        * @param $rcid Integer: ??? FIXME (default 0)
-        * @param $refreshCache boolean If set, refreshes the diff cache
-        * @param $htmldiff boolean If set, output using HTMLDiff instead of raw wikicode diff
-        */
-       function __construct( $titleObj = null, $old = 0, $new = 0, $rcid = 0, $refreshCache = false , $htmldiff = false) {
-               $this->mTitle = $titleObj;
-               wfDebug("DifferenceEngine old '$old' new '$new' rcid '$rcid'\n");
-
-               if ( 'prev' === $new ) {
-                       # Show diff between revision $old and the previous one.
-                       # Get previous one from DB.
-                       #
-                       $this->mNewid = intval($old);
-
-                       $this->mOldid = $this->mTitle->getPreviousRevisionID( $this->mNewid );
-
-               } elseif ( 'next' === $new ) {
-                       # Show diff between revision $old and the previous one.
-                       # Get previous one from DB.
-                       #
-                       $this->mOldid = intval($old);
-                       $this->mNewid = $this->mTitle->getNextRevisionID( $this->mOldid );
-                       if ( false === $this->mNewid ) {
-                               # if no result, NewId points to the newest old revision. The only newer
-                               # revision is cur, which is "0".
-                               $this->mNewid = 0;
-                       }
-
-               } else {
-                       $this->mOldid = intval($old);
-                       $this->mNewid = intval($new);
-               }
-               $this->mRcidMarkPatrolled = intval($rcid);  # force it to be an integer
-               $this->mRefreshCache = $refreshCache;
-               $this->htmldiff = $htmldiff;
-       }
-
-       function getTitle() {
-               return $this->mTitle;
-       }
-
-       function showDiffPage( $diffOnly = false ) {
-               global $wgUser, $wgOut, $wgUseExternalEditor, $wgUseRCPatrol, $wgEnableHtmlDiff;
-               wfProfileIn( __METHOD__ );
-
-
-               # If external diffs are enabled both globally and for the user,
-               # we'll use the application/x-external-editor interface to call
-               # an external diff tool like kompare, kdiff3, etc.
-               if($wgUseExternalEditor && $wgUser->getOption('externaldiff')) {
-                       global $wgInputEncoding,$wgServer,$wgScript,$wgLang;
-                       $wgOut->disable();
-                       header ( "Content-type: application/x-external-editor; charset=".$wgInputEncoding );
-                       $url1=$this->mTitle->getFullURL("action=raw&oldid=".$this->mOldid);
-                       $url2=$this->mTitle->getFullURL("action=raw&oldid=".$this->mNewid);
-                       $special=$wgLang->getNsText(NS_SPECIAL);
-                       $control=<<<CONTROL
-                       [Process]
-                       Type=Diff text
-                       Engine=MediaWiki
-                       Script={$wgServer}{$wgScript}
-                       Special namespace={$special}
-
-                       [File]
-                       Extension=wiki
-                       URL=$url1
-
-                       [File 2]
-                       Extension=wiki
-                       URL=$url2
-CONTROL;
-                       echo($control);
-                       return;
-               }
-
-               $wgOut->setArticleFlag( false );
-               if ( ! $this->loadRevisionData() ) {
-                       $t = $this->mTitle->getPrefixedText();
-                       $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
-                       $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
-                       $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
-                       wfProfileOut( __METHOD__ );
-                       return;
-               }
-
-               wfRunHooks( 'DiffViewHeader', array( $this, $this->mOldRev, $this->mNewRev ) );
-
-               if ( $this->mNewRev->isCurrent() ) {
-                       $wgOut->setArticleFlag( true );
-               }
-
-               # mOldid is false if the difference engine is called with a "vague" query for
-               # a diff between a version V and its previous version V' AND the version V
-               # is the first version of that article. In that case, V' does not exist.
-               if ( $this->mOldid === false ) {
-                       $this->showFirstRevision();
-                       $this->renderNewRevision();  // should we respect $diffOnly here or not?
-                       wfProfileOut( __METHOD__ );
-                       return;
-               }
-
-               $wgOut->suppressQuickbar();
-
-               $oldTitle = $this->mOldPage->getPrefixedText();
-               $newTitle = $this->mNewPage->getPrefixedText();
-               if( $oldTitle == $newTitle ) {
-                       $wgOut->setPageTitle( $newTitle );
-               } else {
-                       $wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
-               }
-               $wgOut->setSubtitle( wfMsg( 'difference' ) );
-               $wgOut->setRobotPolicy( 'noindex,nofollow' );
-
-               if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
-                       $wgOut->loginToUse();
-                       $wgOut->output();
-                       wfProfileOut( __METHOD__ );
-                       exit;
-               }
-
-               $sk = $wgUser->getSkin();
-
-               // Check if page is editable
-               $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
-               if ( $editable && $this->mNewRev->isCurrent() && $wgUser->isAllowed( 'rollback' ) ) {
-                       $rollback = '&nbsp;&nbsp;&nbsp;' . $sk->generateRollback( $this->mNewRev );
-               } else {
-                       $rollback = '';
-               }
-
-               // Prepare a change patrol link, if applicable
-               if( $wgUseRCPatrol && $wgUser->isAllowed( 'patrol' ) ) {
-                       // If we've been given an explicit change identifier, use it; saves time
-                       if( $this->mRcidMarkPatrolled ) {
-                               $rcid = $this->mRcidMarkPatrolled;
-                       } else {
-                               // Look for an unpatrolled change corresponding to this diff
-                               $db = wfGetDB( DB_SLAVE );
-                               $change = RecentChange::newFromConds(
-                               array(
-                               // Add redundant user,timestamp condition so we can use the existing index
-                                               'rc_user_text'  => $this->mNewRev->getRawUserText(),
-                                               'rc_timestamp' => $db->timestamp( $this->mNewRev->getTimestamp() ),
-                                               'rc_this_oldid' => $this->mNewid,
-                                               'rc_last_oldid' => $this->mOldid,
-                                               'rc_patrolled' => 0
-                               ),
-                               __METHOD__
-                               );
-                               if( $change instanceof RecentChange ) {
-                                       $rcid = $change->mAttribs['rc_id'];
-                               } else {
-                                       // None found
-                                       $rcid = 0;
-                               }
-                       }
-                       // Build the link
-                       if( $rcid ) {
-                               $patrol = ' <span class="patrollink">[' . $sk->makeKnownLinkObj(
-                               $this->mTitle,
-                               wfMsgHtml( 'markaspatrolleddiff' ),
-                                       "action=markpatrolled&rcid={$rcid}"
-                               ) . ']</span>';
-                       } else {
-                               $patrol = '';
-                       }
-               } else {
-                       $patrol = '';
-               }
-
-               $htmldiffarg = $this->htmlDiffArgument();
-               $prevlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'previousdiff' ),
-                       'diff=prev&oldid='.$this->mOldid.$htmldiffarg, '', '', 'id="differences-prevlink"' );
-               if ( $this->mNewRev->isCurrent() ) {
-                       $nextlink = '&nbsp;';
-               } else {
-                       $nextlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'nextdiff' ),
-                               'diff=next&oldid='.$this->mNewid.$htmldiffarg, '', '', 'id="differences-nextlink"' );
-               }
-
-               $oldminor = '';
-               $newminor = '';
-
-               if ($this->mOldRev->mMinorEdit == 1) {
-                       $oldminor = Xml::span( wfMsg( 'minoreditletter'), 'minor' ) . ' ';
-               }
-
-               if ($this->mNewRev->mMinorEdit == 1) {
-                       $newminor = Xml::span( wfMsg( 'minoreditletter'), 'minor' ) . ' ';
-               }
-
-               $rdel = ''; $ldel = '';
-               if( $wgUser->isAllowed( 'deleterevision' ) ) {
-                       $revdel = SpecialPage::getTitleFor( 'Revisiondelete' );
-                       if( !$this->mOldRev->userCan( Revision::DELETED_RESTRICTED ) ) {
-                               // If revision was hidden from sysops
-                               $ldel = wfMsgHtml('rev-delundel');
-                       } else {
-                               $ldel = $sk->makeKnownLinkObj( $revdel,
-                               wfMsgHtml('rev-delundel'),
-                                       'target=' . urlencode( $this->mOldRev->mTitle->getPrefixedDbkey() ) .
-                                       '&oldid=' . urlencode( $this->mOldRev->getId() ) );
-                               // Bolden oversighted content
-                               if( $this->mOldRev->isDeleted( Revision::DELETED_RESTRICTED ) )
-                               $ldel = "<strong>$ldel</strong>";
-                       }
-                       $ldel = "&nbsp;&nbsp;&nbsp;<tt>(<small>$ldel</small>)</tt> ";
-                       // We don't currently handle well changing the top revision's settings
-                       if( $this->mNewRev->isCurrent() ) {
-                               // If revision was hidden from sysops
-                               $rdel = wfMsgHtml('rev-delundel');
-                       } else if( !$this->mNewRev->userCan( Revision::DELETED_RESTRICTED ) ) {
-                               // If revision was hidden from sysops
-                               $rdel = wfMsgHtml('rev-delundel');
-                       } else {
-                               $rdel = $sk->makeKnownLinkObj( $revdel,
-                               wfMsgHtml('rev-delundel'),
-                                       'target=' . urlencode( $this->mNewRev->mTitle->getPrefixedDbkey() ) .
-                                       '&oldid=' . urlencode( $this->mNewRev->getId() ) );
-                               // Bolden oversighted content
-                               if( $this->mNewRev->isDeleted( Revision::DELETED_RESTRICTED ) )
-                               $rdel = "<strong>$rdel</strong>";
-                       }
-                       $rdel = "&nbsp;&nbsp;&nbsp;<tt>(<small>$rdel</small>)</tt> ";
-               }
-
-               $oldHeader = '<div id="mw-diff-otitle1"><strong>'.$this->mOldtitle.'</strong></div>' .
-                       '<div id="mw-diff-otitle2">' . $sk->revUserTools( $this->mOldRev, true ) . "</div>" .
-                       '<div id="mw-diff-otitle3">' . $oldminor . $sk->revComment( $this->mOldRev, !$diffOnly, true ) . $ldel . "</div>" .
-                       '<div id="mw-diff-otitle4">' . $prevlink .'</div>';
-               $newHeader = '<div id="mw-diff-ntitle1"><strong>'.$this->mNewtitle.'</strong></div>' .
-                       '<div id="mw-diff-ntitle2">' . $sk->revUserTools( $this->mNewRev, true ) . " $rollback</div>" .
-                       '<div id="mw-diff-ntitle3">' . $newminor . $sk->revComment( $this->mNewRev, !$diffOnly, true ) . $rdel . "</div>" .
-                       '<div id="mw-diff-ntitle4">' . $nextlink . $patrol . '</div>';
-
-               if( $wgEnableHtmlDiff && $this->htmldiff) {
-                       $multi = $this->getMultiNotice();
-                       $wgOut->addHTML('<div class="diff-switchtype">'.$sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'wikicodecomparison' ),
-                       'diff='.$this->mNewid.'&oldid='.$this->mOldid.'&htmldiff=0', '', '', 'id="differences-switchtype"' ).'</div>');
-                       $wgOut->addHTML( $this->addHeader( '', $oldHeader, $newHeader, $multi ) );
-                       $this->renderHtmlDiff();
-               } else {
-                       if($wgEnableHtmlDiff){
-                               $wgOut->addHTML('<div class="diff-switchtype">'.$sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'visualcomparison' ),
-                               'diff='.$this->mNewid.'&oldid='.$this->mOldid.'&htmldiff=1', '', '', 'id="differences-switchtype"' ).'</div>');
-                       }
-                       $this->showDiff( $oldHeader, $newHeader );
-                       if( !$diffOnly ) {
-                               $this->renderNewRevision();
-                       }
-               }
-               wfProfileOut( __METHOD__ );
-       }
-
-       /**
-        * Show the new revision of the page.
-        */
-       function renderNewRevision() {
-               global $wgOut;
-               wfProfileIn( __METHOD__ );
-
-               $wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
-               #add deleted rev tag if needed
-               if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
-                       $wgOut->addWikiMsg( 'rev-deleted-text-permission' );
-               } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
-                       $wgOut->addWikiMsg( 'rev-deleted-text-view' );
-               }
-
-               if( !$this->mNewRev->isCurrent() ) {
-                       $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
-               }
-
-               $this->loadNewText();
-               if( is_object( $this->mNewRev ) ) {
-                       $wgOut->setRevisionId( $this->mNewRev->getId() );
-               }
-
-               if ($this->mTitle->isCssJsSubpage() || $this->mTitle->isCssOrJsPage()) {
-                       // Stolen from Article::view --AG 2007-10-11
-
-                       // Give hooks a chance to customise the output
-                       if( wfRunHooks( 'ShowRawCssJs', array( $this->mNewtext, $this->mTitle, $wgOut ) ) ) {
-                               // Wrap the whole lot in a <pre> and don't parse
-                               $m = array();
-                               preg_match( '!\.(css|js)$!u', $this->mTitle->getText(), $m );
-                               $wgOut->addHtml( "<pre class=\"mw-code mw-{$m[1]}\" dir=\"ltr\">\n" );
-                               $wgOut->addHtml( htmlspecialchars( $this->mNewtext ) );
-                               $wgOut->addHtml( "\n</pre>\n" );
-                       }
-               } else
-               $wgOut->addWikiTextTidy( $this->mNewtext );
-
-               if( !$this->mNewRev->isCurrent() ) {
-                       $wgOut->parserOptions()->setEditSection( $oldEditSectionSetting );
-               }
-
-               wfProfileOut( __METHOD__ );
-       }
-
-
-       function renderHtmlDiff() {
-               global $wgOut, $wgTitle, $wgParser, $wgDebugComments;
-               wfProfileIn( __METHOD__ );
-
-               $this->showDiffStyle();
-
-               $wgOut->addHTML( '<h2>'.wfMsgHtml( 'visual-comparison' )."</h2>\n" );
-               #add deleted rev tag if needed
-               if( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
-                       $wgOut->addWikiMsg( 'rev-deleted-text-permission' );
-               } else if( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
-                       $wgOut->addWikiMsg( 'rev-deleted-text-view' );
-               }
-
-               if( !$this->mNewRev->isCurrent() ) {
-                       $oldEditSectionSetting = $wgOut->parserOptions()->setEditSection( false );
-               }
-
-               $this->loadText();
-
-               // Old revision
-               if( is_object( $this->mOldRev ) ) {
-                       $wgOut->setRevisionId( $this->mOldRev->getId() );
-               }
-
-               $popts = $wgOut->parserOptions();
-               $oldTidy = $popts->setTidy( true );
-               $popts->setEditSection( false );
-
-               $parserOutput = $wgParser->parse( $this->mOldtext, $wgTitle, $popts, true, true, $wgOut->getRevisionId() );
-               $popts->setTidy( $oldTidy );
-
-               //only for new?
-               //$wgOut->addParserOutputNoText( $parserOutput );
-               $oldHtml = $parserOutput->getText();
-               wfRunHooks( 'OutputPageBeforeHTML', array( &$wgOut, &$oldHtml ) );
-
-               // New revision
-               if( is_object( $this->mNewRev ) ) {
-                       $wgOut->setRevisionId( $this->mNewRev->getId() );
-               }
-
-               $popts = $wgOut->parserOptions();
-               $oldTidy = $popts->setTidy( true );
-
-               $parserOutput = $wgParser->parse( $this->mNewtext, $wgTitle, $popts, true, true, $wgOut->getRevisionId() );
-               $popts->setTidy( $oldTidy );
-
-               $wgOut->addParserOutputNoText( $parserOutput );
-               $newHtml = $parserOutput->getText();
-               wfRunHooks( 'OutputPageBeforeHTML', array( &$wgOut, &$newHtml ) );
-
-               unset($parserOutput, $popts);
-
-               $differ = new HTMLDiffer(new DelegatingContentHandler($wgOut));
-               $differ->htmlDiff($oldHtml, $newHtml);
-               if ( $wgDebugComments ) {
-                       $wgOut->addHtml( "\n<!-- HtmlDiff Debug Output:\n" . HTMLDiffer::getDebugOutput() . " End Debug -->" );
-               }
-
-               wfProfileOut( __METHOD__ );
-       }
-
-       /**
-        * Show the first revision of an article. Uses normal diff headers in
-        * contrast to normal "old revision" display style.
-        */
-       function showFirstRevision() {
-               global $wgOut, $wgUser;
-               wfProfileIn( __METHOD__ );
-
-               # Get article text from the DB
-               #
-               if ( ! $this->loadNewText() ) {
-                       $t = $this->mTitle->getPrefixedText();
-                       $d = wfMsgExt( 'missingarticle-diff', array( 'escape' ), $this->mOldid, $this->mNewid );
-                       $wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
-                       $wgOut->addWikiMsg( 'missing-article', "<nowiki>$t</nowiki>", $d );
-                       wfProfileOut( __METHOD__ );
-                       return;
-               }
-               if ( $this->mNewRev->isCurrent() ) {
-                       $wgOut->setArticleFlag( true );
-               }
-
-               # Check if user is allowed to look at this page. If not, bail out.
-               #
-               if ( !( $this->mTitle->userCanRead() ) ) {
-                       $wgOut->loginToUse();
-                       $wgOut->output();
-                       wfProfileOut( __METHOD__ );
-                       exit;
-               }
-
-               # Prepare the header box
-               #
-               $sk = $wgUser->getSkin();
-
-               $nextlink = $sk->makeKnownLinkObj( $this->mTitle, wfMsgHtml( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid.$this->htmlDiffArgument(), '', '', 'id="differences-nextlink"' );
-               $header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />" .
-               $sk->revUserTools( $this->mNewRev ) . "<br />" .
-               $sk->revComment( $this->mNewRev ) . "<br />" .
-               $nextlink . "</div>\n";
-
-               $wgOut->addHTML( $header );
-
-               $wgOut->setSubtitle( wfMsg( 'difference' ) );
-               $wgOut->setRobotPolicy( 'noindex,nofollow' );
-
-               wfProfileOut( __METHOD__ );
-       }
-
-       function htmlDiffArgument(){
-               global $wgEnableHtmlDiff;
-               if($wgEnableHtmlDiff){
-                       if($this->htmldiff){
-                               return '&htmldiff=1';
-                       }else{
-                               return '&htmldiff=0';
-                       }
-               }else{
-                       return '';
-               }
-       }
-
-       /**
-        * Get the diff text, send it to $wgOut
-        * Returns false if the diff could not be generated, otherwise returns true
-        */
-       function showDiff( $otitle, $ntitle ) {
-               global $wgOut;
-               $diff = $this->getDiff( $otitle, $ntitle );
-               if ( $diff === false ) {
-                       $wgOut->addWikiMsg( 'missing-article', "<nowiki>(fixme, bug)</nowiki>", '' );
-                       return false;
-               } else {
-                       $this->showDiffStyle();
-                       $wgOut->addHTML( $diff );
-                       return true;
-               }
-       }
-
-       /**
-        * Add style sheets and supporting JS for diff display.
-        */
-       function showDiffStyle() {
-               global $wgStylePath, $wgStyleVersion, $wgOut;
-               $wgOut->addStyle( 'common/diff.css' );
-
-               // JS is needed to detect old versions of Mozilla to work around an annoyance bug.
-               $wgOut->addScript( "<script type=\"text/javascript\" src=\"$wgStylePath/common/diff.js?$wgStyleVersion\"></script>" );
-       }
-
-       /**
-        * Get complete diff table, including header
-        *
-        * @param Title $otitle Old title
-        * @param Title $ntitle New title
-        * @return mixed
-        */
-       function getDiff( $otitle, $ntitle ) {
-               $body = $this->getDiffBody();
-               if ( $body === false ) {
-                       return false;
-               } else {
-                       $multi = $this->getMultiNotice();
-                       return $this->addHeader( $body, $otitle, $ntitle, $multi );
-               }
-       }
-
-       /**
-        * Get the diff table body, without header
-        *
-        * @return mixed
-        */
-       function getDiffBody() {
-               global $wgMemc;
-               wfProfileIn( __METHOD__ );
-               // Check if the diff should be hidden from this user
-               if ( $this->mOldRev && !$this->mOldRev->userCan(Revision::DELETED_TEXT) ) {
-                       return '';
-               } else if ( $this->mNewRev && !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
-                       return '';
-               }
-               // Cacheable?
-               $key = false;
-               if ( $this->mOldid && $this->mNewid ) {
-                       $key = wfMemcKey( 'diff', 'version', MW_DIFF_VERSION, 'oldid', $this->mOldid, 'newid', $this->mNewid );
-                       // Try cache
-                       if ( !$this->mRefreshCache ) {
-                               $difftext = $wgMemc->get( $key );
-                               if ( $difftext ) {
-                                       wfIncrStats( 'diff_cache_hit' );
-                                       $difftext = $this->localiseLineNumbers( $difftext );
-                                       $difftext .= "\n<!-- diff cache key $key -->\n";
-                                       wfProfileOut( __METHOD__ );
-                                       return $difftext;
-                               }
-                       } // don't try to load but save the result
-               }
-
-               // Loadtext is permission safe, this just clears out the diff
-               if ( !$this->loadText() ) {
-                       wfProfileOut( __METHOD__ );
-                       return false;
-               }
-
-               $difftext = $this->generateDiffBody( $this->mOldtext, $this->mNewtext );
-
-               // Save to cache for 7 days
-               if ( $key !== false && $difftext !== false ) {
-                       wfIncrStats( 'diff_cache_miss' );
-                       $wgMemc->set( $key, $difftext, 7*86400 );
-               } else {
-                       wfIncrStats( 'diff_uncacheable' );
-               }
-               // Replace line numbers with the text in the user's language
-               if ( $difftext !== false ) {
-                       $difftext = $this->localiseLineNumbers( $difftext );
-               }
-               wfProfileOut( __METHOD__ );
-               return $difftext;
-       }
-
-       /**
-        * Generate a diff, no caching
-        * $otext and $ntext must be already segmented
-        */
-       function generateDiffBody( $otext, $ntext ) {
-               global $wgExternalDiffEngine, $wgContLang;
-
-               $otext = str_replace( "\r\n", "\n", $otext );
-               $ntext = str_replace( "\r\n", "\n", $ntext );
-
-               if ( $wgExternalDiffEngine == 'wikidiff' ) {
-                       # For historical reasons, external diff engine expects
-                       # input text to be HTML-escaped already
-                       $otext = htmlspecialchars ( $wgContLang->segmentForDiff( $otext ) );
-                       $ntext = htmlspecialchars ( $wgContLang->segmentForDiff( $ntext ) );
-                       if( !function_exists( 'wikidiff_do_diff' ) ) {
-                               dl('php_wikidiff.so');
-                       }
-                       return $wgContLang->unsegementForDiff( wikidiff_do_diff( $otext, $ntext, 2 ) ) .
-                       $this->debug( 'wikidiff1' );
-               }
-
-               if ( $wgExternalDiffEngine == 'wikidiff2' ) {
-                       # Better external diff engine, the 2 may some day be dropped
-                       # This one does the escaping and segmenting itself
-                       if ( !function_exists( 'wikidiff2_do_diff' ) ) {
-                               wfProfileIn( __METHOD__ . "-dl" );
-                               @dl('php_wikidiff2.so');
-                               wfProfileOut( __METHOD__ . "-dl" );
-                       }
-                       if ( function_exists( 'wikidiff2_do_diff' ) ) {
-                               wfProfileIn( 'wikidiff2_do_diff' );
-                               $text = wikidiff2_do_diff( $otext, $ntext, 2 );
-                               $text .= $this->debug( 'wikidiff2' );
-                               wfProfileOut( 'wikidiff2_do_diff' );
-                               return $text;
-                       }
-               }
-               if ( $wgExternalDiffEngine != 'wikidiff3' && $wgExternalDiffEngine !== false ) {
-                       # Diff via the shell
-                       global $wgTmpDirectory;
-                       $tempName1 = tempnam( $wgTmpDirectory, 'diff_' );
-                       $tempName2 = tempnam( $wgTmpDirectory, 'diff_' );
-
-                       $tempFile1 = fopen( $tempName1, "w" );
-                       if ( !$tempFile1 ) {
-                               wfProfileOut( __METHOD__ );
-                               return false;
-                       }
-                       $tempFile2 = fopen( $tempName2, "w" );
-                       if ( !$tempFile2 ) {
-                               wfProfileOut( __METHOD__ );
-                               return false;
-                       }
-                       fwrite( $tempFile1, $otext );
-                       fwrite( $tempFile2, $ntext );
-                       fclose( $tempFile1 );
-                       fclose( $tempFile2 );
-                       $cmd = wfEscapeShellArg( $wgExternalDiffEngine, $tempName1, $tempName2 );
-                       wfProfileIn( __METHOD__ . "-shellexec" );
-                       $difftext = wfShellExec( $cmd );
-                       $difftext .= $this->debug( "external $wgExternalDiffEngine" );
-                       wfProfileOut( __METHOD__ . "-shellexec" );
-                       unlink( $tempName1 );
-                       unlink( $tempName2 );
-                       return $difftext;
-               }
-
-               # Native PHP diff
-               $ota = explode( "\n", $wgContLang->segmentForDiff( $otext ) );
-               $nta = explode( "\n", $wgContLang->segmentForDiff( $ntext ) );
-               $diffs = new Diff( $ota, $nta );
-               $formatter = new TableDiffFormatter();
-               return $wgContLang->unsegmentForDiff( $formatter->format( $diffs ) ) .
-               $this->debug();
-       }
-
-       /**
-        * Generate a debug comment indicating diff generating time,
-        * server node, and generator backend.
-        */
-       protected function debug( $generator="internal" ) {
-               global $wgShowHostnames, $wgNodeName;
-               $data = array( $generator );
-               if( $wgShowHostnames ) {
-                       $data[] = $wgNodeName;
-               }
-               $data[] = wfTimestamp( TS_DB );
-               return "<!-- diff generator: " .
-               implode( " ",
-               array_map(
-                                       "htmlspecialchars",
-               $data ) ) .
-                       " -->\n";
-       }
-
-       /**
-        * Replace line numbers with the text in the user's language
-        */
-       function localiseLineNumbers( $text ) {
-               return preg_replace_callback( '/<!--LINE (\d+)-->/',
-               array( &$this, 'localiseLineNumbersCb' ), $text );
-       }
-
-       function localiseLineNumbersCb( $matches ) {
-               global $wgLang;
-               return wfMsgExt( 'lineno', array('parseinline'), $wgLang->formatNum( $matches[1] ) );
-       }
-
-
-       /**
-        * If there are revisions between the ones being compared, return a note saying so.
-        */
-       function getMultiNotice() {
-               if ( !is_object($this->mOldRev) || !is_object($this->mNewRev) )
-               return '';
-
-               if( !$this->mOldPage->equals( $this->mNewPage ) ) {
-                       // Comparing two different pages? Count would be meaningless.
-                       return '';
-               }
-
-               $oldid = $this->mOldRev->getId();
-               $newid = $this->mNewRev->getId();
-               if ( $oldid > $newid ) {
-                       $tmp = $oldid; $oldid = $newid; $newid = $tmp;
-               }
-
-               $n = $this->mTitle->countRevisionsBetween( $oldid, $newid );
-               if ( !$n )
-               return '';
-
-               return wfMsgExt( 'diff-multi', array( 'parseinline' ), $n );
-       }
-
-
-       /**
-        * Add the header to a diff body
-        */
-       static function addHeader( $diff, $otitle, $ntitle, $multi = '' ) {
-               $header = "
-               <table class='diff'>
-               <col class='diff-marker' />
-               <col class='diff-content' />
-               <col class='diff-marker' />
-               <col class='diff-content' />
-               <tr valign='top'>
-               <td colspan='2' class='diff-otitle'>{$otitle}</td>
-               <td colspan='2' class='diff-ntitle'>{$ntitle}</td>
-               </tr>
-               ";
-
-               if ( $multi != '' )
-               $header .= "<tr><td colspan='4' align='center' class='diff-multi'>{$multi}</td></tr>";
-
-               return $header . $diff . "</table>";
-       }
-
-       /**
-        * Use specified text instead of loading from the database
-        */
-       function setText( $oldText, $newText ) {
-               $this->mOldtext = $oldText;
-               $this->mNewtext = $newText;
-               $this->mTextLoaded = 2;
-       }
-
-       /**
-        * Load revision metadata for the specified articles. If newid is 0, then compare
-        * the old article in oldid to the current article; if oldid is 0, then
-        * compare the current article to the immediately previous one (ignoring the
-        * value of newid).
-        *
-        * If oldid is false, leave the corresponding revision object set
-        * to false. This is impossible via ordinary user input, and is provided for
-        * API convenience.
-        */
-       function loadRevisionData() {
-               global $wgLang;
-               if ( $this->mRevisionsLoaded ) {
-                       return true;
-               } else {
-                       // Whether it succeeds or fails, we don't want to try again
-                       $this->mRevisionsLoaded = true;
-               }
-
-               // Load the new revision object
-               $this->mNewRev = $this->mNewid
-               ? Revision::newFromId( $this->mNewid )
-               : Revision::newFromTitle( $this->mTitle );
-               if( !$this->mNewRev instanceof Revision )
-               return false;
-
-               // Update the new revision ID in case it was 0 (makes life easier doing UI stuff)
-               $this->mNewid = $this->mNewRev->getId();
-
-               // Check if page is editable
-               $editable = $this->mNewRev->getTitle()->userCan( 'edit' );
-
-               // Set assorted variables
-               $timestamp = $wgLang->timeanddate( $this->mNewRev->getTimestamp(), true );
-               $this->mNewPage = $this->mNewRev->getTitle();
-               if( $this->mNewRev->isCurrent() ) {
-                       $newLink = $this->mNewPage->escapeLocalUrl( 'oldid=' . $this->mNewid );
-                       $this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
-                       $newEdit = $this->mNewPage->escapeLocalUrl( 'action=edit' );
-
-                       $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a> ($timestamp)";
-                       $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
-
-               } else {
-                       $newLink = $this->mNewPage->escapeLocalUrl( 'oldid=' . $this->mNewid );
-                       $newEdit = $this->mNewPage->escapeLocalUrl( 'action=edit&oldid=' . $this->mNewid );
-                       $this->mPagetitle = wfMsgHTML( 'revisionasof', $timestamp );
-
-                       $this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
-                       $this->mNewtitle .= " (<a href='$newEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
-               }
-               if ( !$this->mNewRev->userCan(Revision::DELETED_TEXT) ) {
-                       $this->mNewtitle = "<span class='history-deleted'>{$this->mPagetitle}</span>";
-               } else if ( $this->mNewRev->isDeleted(Revision::DELETED_TEXT) ) {
-                       $this->mNewtitle = '<span class="history-deleted">'.$this->mNewtitle.'</span>';
-               }
-
-               // Load the old revision object
-               $this->mOldRev = false;
-               if( $this->mOldid ) {
-                       $this->mOldRev = Revision::newFromId( $this->mOldid );
-               } elseif ( $this->mOldid === 0 ) {
-                       $rev = $this->mNewRev->getPrevious();
-                       if( $rev ) {
-                               $this->mOldid = $rev->getId();
-                               $this->mOldRev = $rev;
-                       } else {
-                               // No previous revision; mark to show as first-version only.
-                               $this->mOldid = false;
-                               $this->mOldRev = false;
-                       }
-               }/* elseif ( $this->mOldid === false ) leave mOldRev false; */
-
-               if( is_null( $this->mOldRev ) ) {
-                       return false;
-               }
-
-               if ( $this->mOldRev ) {
-                       $this->mOldPage = $this->mOldRev->getTitle();
-
-                       $t = $wgLang->timeanddate( $this->mOldRev->getTimestamp(), true );
-                       $oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
-                       $oldEdit = $this->mOldPage->escapeLocalUrl( 'action=edit&oldid=' . $this->mOldid );
-                       $this->mOldPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
-
-                       $this->mOldtitle = "<a href='$oldLink'>{$this->mOldPagetitle}</a>"
-                       . " (<a href='$oldEdit'>" . wfMsgHtml( $editable ? 'editold' : 'viewsourceold' ) . "</a>)";
-                       // Add an "undo" link
-                       $newUndo = $this->mNewPage->escapeLocalUrl( 'action=edit&undoafter=' . $this->mOldid . '&undo=' . $this->mNewid);
-                       if( $editable && !$this->mOldRev->isDeleted( Revision::DELETED_TEXT ) && !$this->mNewRev->isDeleted( Revision::DELETED_TEXT ) ) {
-                               $this->mNewtitle .= " (<a href='$newUndo'>" . htmlspecialchars( wfMsg( 'editundo' ) ) . "</a>)";
-                       }
-
-                       if( !$this->mOldRev->userCan( Revision::DELETED_TEXT ) ) {
-                               $this->mOldtitle = '<span class="history-deleted">' . $this->mOldPagetitle . '</span>';
-                       } else if( $this->mOldRev->isDeleted( Revision::DELETED_TEXT ) ) {
-                               $this->mOldtitle = '<span class="history-deleted">' . $this->mOldtitle . '</span>';
-                       }
-               }
-
-               return true;
-       }
-
-       /**
-        * Load the text of the revisions, as well as revision data.
-        */
-       function loadText() {
-               if ( $this->mTextLoaded == 2 ) {
-                       return true;
-               } else {
-                       // Whether it succeeds or fails, we don't want to try again
-                       $this->mTextLoaded = 2;
-               }
-
-               if ( !$this->loadRevisionData() ) {
-                       return false;
-               }
-               if ( $this->mOldRev ) {
-                       $this->mOldtext = $this->mOldRev->revText();
-                       if ( $this->mOldtext === false ) {
-                               return false;
-                       }
-               }
-               if ( $this->mNewRev ) {
-                       $this->mNewtext = $this->mNewRev->revText();
-                       if ( $this->mNewtext === false ) {
-                               return false;
-                       }
-               }
-               return true;
-       }
-
-       /**
-        * Load the text of the new revision, not the old one
-        */
-       function loadNewText() {
-               if ( $this->mTextLoaded >= 1 ) {
-                       return true;
-               } else {
-                       $this->mTextLoaded = 1;
-               }
-               if ( !$this->loadRevisionData() ) {
-                       return false;
-               }
-               $this->mNewtext = $this->mNewRev->getText();
-               return true;
-       }
-
-
-}
-
 // A PHP diff engine for phpwiki. (Taken from phpwiki-1.3.3)
 //
 // Copyright (C) 2000, 2001 Geoffrey T. Dairiki <dairiki@dairiki.org>
 // You may copy this code freely under the conditions of the GPL.
 //
 
-define('USE_ASSERTS', function_exists('assert'));
-
 /**
  * @todo document
  * @private
@@ -1028,8 +151,8 @@ class _DiffEngine {
                $edits = array();
                $xi = $yi = 0;
                while ($xi < $n_from || $yi < $n_to) {
-                       USE_ASSERTS && assert($yi < $n_to || $this->xchanged[$xi]);
-                       USE_ASSERTS && assert($xi < $n_from || $this->ychanged[$yi]);
+                       assert($yi < $n_to || $this->xchanged[$xi]);
+                       assert($xi < $n_from || $this->ychanged[$yi]);
 
                        // Skip matching "snake".
                        $copy = array();
@@ -1191,13 +314,13 @@ class _DiffEngine {
                                while (list ($junk, $y) = each($matches))
                                if (empty($this->in_seq[$y])) {
                                        $k = $this->_lcs_pos($y);
-                                       USE_ASSERTS && assert($k > 0);
+                                       assert($k > 0);
                                        $ymids[$k] = $ymids[$k-1];
                                        break;
                                }
                                while (list ( /* $junk */, $y) = each($matches)) {
                                        if ($y > $this->seq[$k-1]) {
-                                               USE_ASSERTS && assert($y < $this->seq[$k]);
+                                               assert($y < $this->seq[$k]);
                                                // Optimization: this is a common case:
                                                //      next match is just replacing previous match.
                                                $this->in_seq[$this->seq[$k]] = false;
@@ -1205,7 +328,7 @@ class _DiffEngine {
                                                $this->in_seq[$y] = 1;
                                        } else if (empty($this->in_seq[$y])) {
                                                $k = $this->_lcs_pos($y);
-                                               USE_ASSERTS && assert($k > 0);
+                                               assert($k > 0);
                                                $ymids[$k] = $ymids[$k-1];
                                        }
                                }
@@ -1241,7 +364,7 @@ class _DiffEngine {
                        $end = $mid;
                }
 
-               USE_ASSERTS && assert($ypos != $this->seq[$end]);
+               assert($ypos != $this->seq[$end]);
 
                $this->in_seq[$this->seq[$end]] = false;
                $this->seq[$end] = $ypos;
@@ -1321,7 +444,7 @@ class _DiffEngine {
                $i = 0;
                $j = 0;
 
-               USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
+               assert('sizeof($lines) == sizeof($changed)');
                $len = sizeof($lines);
                $other_len = sizeof($other_changed);
 
@@ -1341,7 +464,7 @@ class _DiffEngine {
                        $j++;
 
                        while ($i < $len && ! $changed[$i]) {
-                               USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
+                               assert('$j < $other_len && ! $other_changed[$j]');
                                $i++; $j++;
                                while ($j < $other_len && $other_changed[$j])
                                $j++;
@@ -1373,10 +496,10 @@ class _DiffEngine {
                                        $changed[--$i] = false;
                                        while ($start > 0 && $changed[$start - 1])
                                        $start--;
-                                       USE_ASSERTS && assert('$j > 0');
+                                       assert('$j > 0');
                                        while ($other_changed[--$j])
                                        continue;
-                                       USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
+                                       assert('$j >= 0 && !$other_changed[$j]');
                                }
 
                                /*
@@ -1399,7 +522,7 @@ class _DiffEngine {
                                        while ($i < $len && $changed[$i])
                                        $i++;
 
-                                       USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
+                                       assert('$j < $other_len && ! $other_changed[$j]');
                                        $j++;
                                        if ($j < $other_len && $other_changed[$j]) {
                                                $corresponding = $i;
@@ -1416,10 +539,10 @@ class _DiffEngine {
                        while ($corresponding < $i) {
                                $changed[--$start] = 1;
                                $changed[--$i] = 0;
-                               USE_ASSERTS && assert('$j > 0');
+                               assert('$j > 0');
                                while ($other_changed[--$j])
                                continue;
-                               USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
+                               assert('$j >= 0 && !$other_changed[$j]');
                        }
                }
                wfProfileOut( __METHOD__ );
@@ -2018,9 +1141,9 @@ class TableDiffFormatter extends DiffFormatter {
        }
 
        public static function escapeWhiteSpace( $msg ) {
-               $msg = preg_replace( '/^ /m', '&nbsp; ', $msg );
-               $msg = preg_replace( '/ $/m', ' &nbsp;', $msg );
-               $msg = preg_replace( '/  /', '&nbsp; ', $msg );
+               $msg = preg_replace( '/^ /m', '&#160; ', $msg );
+               $msg = preg_replace( '/ $/m', ' &#160;', $msg );
+               $msg = preg_replace( '/  /', '&#160; ', $msg );
                return $msg;
        }
 
@@ -2064,7 +1187,7 @@ class TableDiffFormatter extends DiffFormatter {
        }
 
        function emptyLine() {
-               return '<td colspan="2">&nbsp;</td>';
+               return '<td colspan="2">&#160;</td>';
        }
 
        function _added( $lines ) {
@@ -2112,4 +1235,4 @@ class TableDiffFormatter extends DiffFormatter {
                }
                wfProfileOut( __METHOD__ );
        }
-}
\ No newline at end of file
+}