X-Git-Url: https://git.heureux-cyclage.org/?a=blobdiff_plain;f=includes%2FDifferenceEngine.php;h=7d910aa842874ac244a152a51b8fe36b8f2960f3;hb=2104f62734f5f16f9f6d78e9782db2375c0805ad;hp=ffe3b6f47204a2926eb6a424a67cf334f1d499cd;hpb=c0e96b915273d1796a1b5180d23fa83b0739f08d;p=lhc%2Fweb%2Fwiklou.git

diff --git a/includes/DifferenceEngine.php b/includes/DifferenceEngine.php
index ffe3b6f472..7d910aa842 100644
--- a/includes/DifferenceEngine.php
+++ b/includes/DifferenceEngine.php
@@ -1,49 +1,98 @@
 <?php
-# See diff.doc
+/**
+ * See diff.doc
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 
+/** */
+require_once( 'Revision.php' );
+
+/**
+ * @todo document
+ * @access public
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class DifferenceEngine {
 	/* private */ var $mOldid, $mNewid;
-	/* private */ var $mOldtitle, $mNewtitle;
+	/* private */ var $mOldtitle, $mNewtitle, $mPagetitle;
 	/* private */ var $mOldtext, $mNewtext;
 	/* private */ var $mOldUser, $mNewUser;
 	/* private */ var $mOldComment, $mNewComment;
 	/* private */ var $mOldPage, $mNewPage;
-	
-	function DifferenceEngine( $old, $new )
+	/* private */ var $mRcidMarkPatrolled;
+
+	function DifferenceEngine( $old, $new, $rcid = 0 )
 	{
-		$this->mOldid = $old;
-		$this->mNewid = $new;
+		global $wgTitle;
+		if ( 'prev' == $new ) {
+			# Show diff between revision $old and the previous one.
+			# Get previous one from DB.
+			#
+			$this->mNewid = intval($old);
+
+			$this->mOldid = $wgTitle->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 = $wgTitle->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
 	}
 
 	function showDiffPage()
 	{
-		global $wgUser, $wgTitle, $wgOut, $wgLang;
-		$fname = "DifferenceEngine::showDiffPage";
+		global $wgUser, $wgTitle, $wgOut, $wgContLang, $wgOnlySysopsCanPatrol, $wgUseRCPatrol;
+		$fname = 'DifferenceEngine::showDiffPage';
 		wfProfileIn( $fname );
-		
+
+		# 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();
+			wfProfileOut( $fname );
+			return;
+		}
+
 		$t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
 		  "{$this->mNewid})";
-		$mtext = wfMsg( "missingarticle", $t );
+		$mtext = wfMsg( 'missingarticle', $t );
 
 		$wgOut->setArticleFlag( false );
 		if ( ! $this->loadText() ) {
-			$wgOut->setPagetitle( wfMsg( "errorpagetitle" ) );
+			$wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
 			$wgOut->addHTML( $mtext );
 			wfProfileOut( $fname );
 			return;
 		}
 		$wgOut->suppressQuickbar();
-		
+
 		$oldTitle = $this->mOldPage->getPrefixedText();
 		$newTitle = $this->mNewPage->getPrefixedText();
 		if( $oldTitle == $newTitle ) {
 			$wgOut->setPageTitle( $newTitle );
 		} else {
-			$wgOut->setPageTitle( $oldTitle . ", " . $newTitle );
+			$wgOut->setPageTitle( $oldTitle . ', ' . $newTitle );
 		}
-		$wgOut->setSubtitle( wfMsg( "difference" ) );
-		$wgOut->setRobotpolicy( "noindex,follow" );
-		
+		$wgOut->setSubtitle( wfMsg( 'difference' ) );
+		$wgOut->setRobotpolicy( 'noindex,follow' );
+
 		if ( !( $this->mOldPage->userCanRead() && $this->mNewPage->userCanRead() ) ) {
 			$wgOut->loginToUse();
 			$wgOut->output();
@@ -52,63 +101,155 @@ class DifferenceEngine {
 		}
 
 		$sk = $wgUser->getSkin();
-		$talk = $wgLang->getNsText( NS_TALK );
-		$contribs = wfMsg( "contribslink" );
-
+		$talk = $wgContLang->getNsText( NS_TALK );
+		$contribs = wfMsg( 'contribslink' );
 
 		$this->mOldComment = $sk->formatComment($this->mOldComment);
 		$this->mNewComment = $sk->formatComment($this->mNewComment);
 
+		$oldUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
+		$newUserLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mNewUser ), $this->mNewUser );
+		$oldUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ), $talk );
+		$newUTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mNewUser ), $talk );
+		$oldContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
+			'target=' . urlencode($this->mOldUser) );
+		$newContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), $contribs,
+			'target=' . urlencode($this->mNewUser) );
+		if ( !$this->mNewid && $wgUser->isAllowed('rollback') ) {
+			$rollback = '&nbsp;&nbsp;&nbsp;<strong>[' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'rollbacklink' ),
+				'action=rollback&from=' . urlencode($this->mNewUser) ) . ']</strong>';
+		} else {
+			$rollback = '';
+		}
+		if ( $wgUseRCPatrol && $this->mRcidMarkPatrolled != 0 && $wgUser->getID() != 0 &&
+		     ( $wgUser->isAllowed('rollback') || !$wgOnlySysopsCanPatrol ) )
+		{
+			$patrol = ' [' . $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'markaspatrolleddiff' ),
+				"action=markpatrolled&rcid={$this->mRcidMarkPatrolled}" ) . ']';
+		} else {
+			$patrol = '';
+		}
 
-		$oldUserLink = $sk->makeLinkObj( Title::makeTitle( NS_USER, $this->mOldUser ), $this->mOldUser );
-		$newUserLink = $sk->makeLinkObj( Title::makeTitle( NS_USER, $this->mNewUser ), $this->mNewUser );
-		$oldUTLink = $sk->makeLinkObj( Title::makeTitle( NS_USER_TALK, $this->mOldUser ), $talk );
-		$newUTLink = $sk->makeLinkObj( Title::makeTitle( NS_USER_TALK, $this->mNewUser ), $talk );
-		$oldContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, "Contributions" ), $contribs,
-			"target=" . urlencode($this->mOldUser) );
-		$newContribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, "Contributions" ), $contribs,
-			"target=" . urlencode($this->mNewUser) );
-		if ( !$this->mNewid && $wgUser->isSysop() ) {
-			$rollback = "&nbsp;&nbsp;&nbsp;<strong>[" . $sk->makeKnownLinkObj( $wgTitle, wfMsg( "rollbacklink" ),
-				"action=rollback&from=" . urlencode($this->mNewUser) ) . "]</strong>";
+		$prevlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'previousdiff' ), 'diff=prev&oldid='.$this->mOldid );
+		if ( $this->mNewid == 0 ) {
+			$nextlink = '';
 		} else {
-			$rollback = "";
+			$nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
 		}
 
-		$oldHeader = "<strong>{$this->mOldtitle}</strong><br />$oldUserLink ($oldUTLink | $oldContribs)<br />". 
-		  $this->mOldComment;
-		$newHeader = "<strong>{$this->mNewtitle}</strong><br />$newUserLink ($newUTLink | $newContribs) $rollback<br />".
-		  $this->mNewComment;
+		$oldHeader = "<strong>{$this->mOldtitle}</strong><br />$oldUserLink " .
+			"($oldUTLink | $oldContribs)<br />" . $this->mOldComment .
+			'<br />' . $prevlink;
+		$newHeader = "<strong>{$this->mNewtitle}</strong><br />$newUserLink " .
+			"($newUTLink | $newContribs) $rollback<br />" . $this->mNewComment .
+			'<br />' . $nextlink . $patrol;
 
 		DifferenceEngine::showDiff( $this->mOldtext, $this->mNewtext,
 		  $oldHeader, $newHeader );
-		$wgOut->addHTML( "<hr /><h2>{$this->mNewtitle}</h2>\n" );
+		$wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
 		$wgOut->addWikiText( $this->mNewtext );
-		
+
 		wfProfileOut( $fname );
 	}
 
-	function showDiff( $otext, $ntext, $otitle, $ntitle )
+	# Show the first revision of an article. Uses normal diff headers in contrast to normal
+	# "old revision" display style.
+	#
+	function showFirstRevision()
 	{
-		global $wgOut;
+		global $wgOut, $wgTitle, $wgUser, $wgLang;
 
-		$ota = explode( "\n", str_replace( "\r\n", "\n",
-		  htmlspecialchars( $otext ) ) );
-		$nta = explode( "\n", str_replace( "\r\n", "\n",
-		  htmlspecialchars( $ntext ) ) );
+		$fname = 'DifferenceEngine::showFirstRevision';
+		wfProfileIn( $fname );
+
+
+		$this->mOldid = $this->mNewid; # hack to make loadText() work.
+
+		# Get article text from the DB
+		#
+		if ( ! $this->loadText() ) {
+			$t = $wgTitle->getPrefixedText() . " (Diff: {$this->mOldid}, " .
+			  "{$this->mNewid})";
+			$mtext = wfMsg( 'missingarticle', $t );
+			$wgOut->setPagetitle( wfMsg( 'errorpagetitle' ) );
+			$wgOut->addHTML( $mtext );
+			wfProfileOut( $fname );
+			return;
+		}
+
+		# Check if user is allowed to look at this page. If not, bail out.
+		#
+		if ( !( $this->mOldPage->userCanRead() ) ) {
+			$wgOut->loginToUse();
+			$wgOut->output();
+			wfProfileOut( $fname );
+			exit;
+		}
 
-		$wgOut->addHTML( "<table border='0' width='98%'
-cellpadding='0' cellspacing='4px' class='diff'><tr>
-<td colspan='2' width='50%' align='center' class='diff-otitle'>
-{$otitle}</td>
-<td colspan='2' width='50%' align='center' class='diff-ntitle'>
-{$ntitle}</td>
-</tr>\n" );
+		# Prepare the header box
+		#
+		$sk = $wgUser->getSkin();
 
-		$diffs = new Diff( $ota, $nta );
-		$formatter = new TableDiffFormatter();
-		$formatter->format( $diffs );
-		$wgOut->addHTML( "</table>\n" );
+		$uTLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER_TALK, $this->mOldUser ),  $wgLang->getNsText( NS_TALK ) );
+		$userLink = $sk->makeLinkObj( Title::makeTitleSafe( NS_USER, $this->mOldUser ), $this->mOldUser );
+		$contribs = $sk->makeKnownLinkObj( Title::makeTitle( NS_SPECIAL, 'Contributions' ), wfMsg( 'contribslink' ),
+			'target=' . urlencode($this->mOldUser) );
+		$nextlink = $sk->makeKnownLinkObj( $wgTitle, wfMsg( 'nextdiff' ), 'diff=next&oldid='.$this->mNewid );
+		$header = "<div class=\"firstrevisionheader\" style=\"text-align: center\"><strong>{$this->mOldtitle}</strong><br />$userLink " .
+			"($uTLink | $contribs)<br />" . $this->mOldComment .
+			'<br />' . $nextlink. "</div>\n";
+
+		$wgOut->addHTML( $header );
+
+		$wgOut->setSubtitle( wfMsg( 'difference' ) );
+		$wgOut->setRobotpolicy( 'noindex,follow' );
+
+
+		# Show current revision
+		#
+		$wgOut->addHTML( "<hr /><h2>{$this->mPagetitle}</h2>\n" );
+		$wgOut->addWikiText( $this->mNewtext );
+
+		wfProfileOut( $fname );
+	}
+
+	function showDiff( $otext, $ntext, $otitle, $ntitle )
+	{
+		global $wgOut;
+		$wgOut->addHTML( DifferenceEngine::getDiff( $otext, $ntext, $otitle, $ntitle ) );
+	}
+	
+	function getDiff( $otext, $ntext, $otitle, $ntitle ) {
+		global $wgUseExternalDiffEngine, $wgContLang;
+		$out = "
+			<table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
+			<tr>
+				<td colspan='2' width='50%' align='center' class='diff-otitle'>{$otitle}</td>
+				<td colspan='2' width='50%' align='center' class='diff-ntitle'>{$ntitle}</td>
+			</tr>
+		";
+		$otext = $wgContLang->segmentForDiff($otext);
+		$ntext = $wgContLang->segmentForDiff($ntext);
+		$difftext='';
+		if ( $wgUseExternalDiffEngine ) {
+			# For historical reasons, external diff engine expects
+			# input text to be HTML-escaped already
+			$otext = str_replace( "\r\n", "\n", htmlspecialchars ( $otext ) );
+			$ntext = str_replace( "\r\n", "\n", htmlspecialchars ( $ntext ) );
+			if( !function_exists( 'wikidiff_do_diff' ) ) {
+				dl('php_wikidiff.so');
+			}
+			$difftext = wikidiff_do_diff( $otext, $ntext, 2 );
+		} else {
+			$ota = explode( "\n", str_replace( "\r\n", "\n", $otext ) );
+			$nta = explode( "\n", str_replace( "\r\n", "\n", $ntext ) );
+			$diffs =& new Diff( $ota, $nta );
+			$formatter =& new TableDiffFormatter();
+			$difftext = $formatter->format( $diffs );
+		}
+		$difftext = $wgContLang->unsegmentForDiff($difftext);
+		$out .= $difftext."</table>\n";
+		return $out;
 	}
 
 	# Load the text of the articles to compare.  If newid is 0, then compare
@@ -118,64 +259,50 @@ cellpadding='0' cellspacing='4px' class='diff'><tr>
 	#
 	function loadText()
 	{
-		global $wgTitle, $wgOut, $wgLang, $wgIsMySQL, $wgIsPg;
-		$fname = "DifferenceEngine::loadText";
+		global $wgTitle, $wgOut, $wgLang;
+		$fname = 'DifferenceEngine::loadText';
+
+		$dbr =& wfGetDB( DB_SLAVE );
+		if( $this->mNewid ) {
+			$this->newRev =& Revision::newFromId( $this->mNewid );
+		} else {
+			$this->newRev =& Revision::newFromTitle( $wgTitle );
+		}
 		
-		$oldtable=wgIsPg?'"old"':'old';
-		if ( 0 == $this->mNewid || 0 == $this->mOldid ) {
-			$wgOut->setArticleFlag( true );
-			$this->mNewtitle = wfMsg( "currentrev" );
-			$id = $wgTitle->getArticleID();
-			
-			$sql = "SELECT cur_text, cur_user_text, cur_comment FROM cur WHERE cur_id={$id}";
-			$res = wfQuery( $sql, DB_READ, $fname );
-			if ( 0 == wfNumRows( $res ) ) { return false; }
-
-			$s = wfFetchObject( $res );
-			$this->mNewPage = &$wgTitle;
-			$this->mNewtext = $s->cur_text;
-			$this->mNewUser = $s->cur_user_text;
-			$this->mNewComment = $s->cur_comment;
+		if( $this->newRev->isCurrent() ) {
+			$this->mPagetitle = htmlspecialchars( wfMsg( 'currentrev' ) );
+			$this->mNewPage = $wgTitle;
+			$newLink = $this->mNewPage->escapeLocalUrl();
+			$this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 		} else {
-			$sql = "SELECT old_namespace,old_title,old_timestamp,old_text,old_flags,old_user_text,old_comment FROM $oldtable WHERE " .
-			  "old_id={$this->mNewid}";
-
-			$res = wfQuery( $sql, DB_READ, $fname );
-			if ( 0 == wfNumRows( $res ) ) { return false; }
-
-			$s = wfFetchObject( $res );
-			$this->mNewtext = Article::getRevisionText( $s );
-
-			$t = $wgLang->timeanddate( $s->old_timestamp, true );
-			$this->mNewPage = Title::MakeTitle( $s->old_namespace, $s->old_title );
-			$this->mNewtitle = wfMsg( "revisionasof", $t );
-			$this->mNewUser = $s->old_user_text;
-			$this->mNewComment = $s->old_comment;
+			$this->mNewPage = $this->newRev->getTitle();
+			$newLink = $this->mNewPage->escapeLocalUrl ('oldid=' . $this->mNewid );
+			$t = $wgLang->timeanddate( $this->newRev->getTimestamp(), true );
+			$this->mPagetitle = htmlspecialchars( wfMsg( 'revisionasof', $t ) );
+			$this->mNewtitle = "<a href='$newLink'>{$this->mPagetitle}</a>";
 		}
-		if ( 0 == $this->mOldid ) {
-			$use_index=$wgIsMySQL?"USE INDEX (name_title_timestamp)":"";
-			$sql = "SELECT old_namespace,old_title,old_timestamp,old_text,old_flags,old_user_text,old_comment " .
-			  "FROM $oldtable $use_index WHERE " .
-			  "old_namespace=" . $this->mNewPage->getNamespace() . " AND " .
-			  "old_title='" . wfStrencode( $this->mNewPage->getDBkey() ) .
-			  "' ORDER BY inverse_timestamp LIMIT 1";
-			$res = wfQuery( $sql, DB_READ, $fname );
+		
+		if( $this->mOldid ) {
+			$this->oldRev =& Revision::newFromId( $this->mOldid );
 		} else {
-			$sql = "SELECT old_namespace,old_title,old_timestamp,old_text,old_flags,old_user_text,old_comment FROM $oldtable WHERE " .
-			  "old_id={$this->mOldid}";
-			$res = wfQuery( $sql, DB_READ, $fname );
+			$this->oldRev =& $this->newRev->getPrevious();
+			$this->mOldid = $this->oldRev->getId();
 		}
-		if ( 0 == wfNumRows( $res ) ) { return false; }
-
-		$s = wfFetchObject( $res );
-		$this->mOldPage = Title::MakeTitle( $s->old_namespace, $s->old_title );
-		$this->mOldtext = Article::getRevisionText( $s );
+			
+		$this->mOldPage = $this->oldRev->getTitle();
 
-		$t = $wgLang->timeanddate( $s->old_timestamp, true );
-		$this->mOldtitle = wfMsg( "revisionasof", $t );
-		$this->mOldUser = $s->old_user_text;
-		$this->mOldComment = $s->old_comment;
+		$t = $wgLang->timeanddate( $this->oldRev->getTimestamp(), true );
+		$oldLink = $this->mOldPage->escapeLocalUrl( 'oldid=' . $this->mOldid );
+		$this->mOldtitle = "<a href='$oldLink'>" . htmlspecialchars( wfMsg( 'revisionasof', $t ) ) . '</a>';
+		
+		$this->mNewUser = $this->newRev->getUserText();
+		$this->mNewComment = $this->newRev->getComment();
+		$this->mNewtext = $this->newRev->getText();
 		
+		$this->mOldUser = $this->oldRev->getUserText();
+		$this->mOldComment = $this->oldRev->getComment();
+		$this->mOldtext = $this->oldRev->getText();
+
 		return true;
 	}
 }
@@ -188,13 +315,19 @@ cellpadding='0' cellspacing='4px' class='diff'><tr>
 
 define('USE_ASSERTS', function_exists('assert'));
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class _DiffOp {
 	var $type;
 	var $orig;
 	var $closing;
-	
+
 	function reverse() {
-		trigger_error("pure virtual", E_USER_ERROR);
+		trigger_error('pure virtual', E_USER_ERROR);
 	}
 
 	function norig() {
@@ -206,9 +339,15 @@ class _DiffOp {
 	}
 }
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class _DiffOp_Copy extends _DiffOp {
 	var $type = 'copy';
-	
+
 	function _DiffOp_Copy ($orig, $closing = false) {
 		if (!is_array($closing))
 			$closing = $orig;
@@ -221,9 +360,15 @@ class _DiffOp_Copy extends _DiffOp {
 	}
 }
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class _DiffOp_Delete extends _DiffOp {
 	var $type = 'delete';
-	
+
 	function _DiffOp_Delete ($lines) {
 		$this->orig = $lines;
 		$this->closing = false;
@@ -234,9 +379,15 @@ class _DiffOp_Delete extends _DiffOp {
 	}
 }
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class _DiffOp_Add extends _DiffOp {
 	var $type = 'add';
-	
+
 	function _DiffOp_Add ($lines) {
 		$this->closing = $lines;
 		$this->orig = false;
@@ -247,9 +398,15 @@ class _DiffOp_Add extends _DiffOp {
 	}
 }
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class _DiffOp_Change extends _DiffOp {
 	var $type = 'change';
-	
+
 	function _DiffOp_Change ($orig, $closing) {
 		$this->orig = $orig;
 		$this->closing = $closing;
@@ -259,8 +416,8 @@ class _DiffOp_Change extends _DiffOp {
 		return new _DiffOp_Change($this->closing, $this->orig);
 	}
 }
-		
-	  
+
+
 /**
  * Class used internally by Diff to actually compute the diffs.
  *
@@ -280,10 +437,15 @@ class _DiffOp_Change extends _DiffOp {
  *
  * @author Geoffrey T. Dairiki
  * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
  */
 class _DiffEngine
 {
 	function diff ($from_lines, $to_lines) {
+		$fname = '_DiffEngine::diff';
+		wfProfileIn( $fname );
+		
 		$n_from = sizeof($from_lines);
 		$n_to = sizeof($to_lines);
 
@@ -293,7 +455,7 @@ class _DiffEngine
 		unset($this->seq);
 		unset($this->in_seq);
 		unset($this->lcs);
-		 
+
 		// Skip leading common lines.
 		for ($skip = 0; $skip < $n_from && $skip < $n_to; $skip++) {
 			if ($from_lines[$skip] != $to_lines[$skip])
@@ -307,7 +469,7 @@ class _DiffEngine
 				break;
 			$this->xchanged[$xi] = $this->ychanged[$yi] = false;
 		}
-		
+
 		// Ignore lines which do not exist in both files.
 		for ($xi = $skip; $xi < $n_from - $endskip; $xi++)
 			$xhash[$from_lines[$xi]] = 1;
@@ -359,7 +521,7 @@ class _DiffEngine
 			$add = array();
 			while ($yi < $n_to && $this->ychanged[$yi])
 				$add[] = $to_lines[$yi++];
-			
+
 			if ($delete && $add)
 				$edits[] = new _DiffOp_Change($delete, $add);
 			elseif ($delete)
@@ -367,9 +529,10 @@ class _DiffEngine
 			elseif ($add)
 				$edits[] = new _DiffOp_Add($add);
 		}
+		wfProfileOut( $fname );
 		return $edits;
 	}
-	
+
 
 	/* Divide the Largest Common Subsequence (LCS) of the sequences
 	 * [XOFF, XLIM) and [YOFF, YLIM) into NCHUNKS approximately equally
@@ -388,102 +551,111 @@ class _DiffEngine
 	 * of the portions it is going to specify.
 	 */
 	function _diag ($xoff, $xlim, $yoff, $ylim, $nchunks) {
-	$flip = false;
-	
-	if ($xlim - $xoff > $ylim - $yoff) {
-		// Things seems faster (I'm not sure I understand why)
-			// when the shortest sequence in X.
-			$flip = true;
-		list ($xoff, $xlim, $yoff, $ylim)
-		= array( $yoff, $ylim, $xoff, $xlim);
+		$fname = '_DiffEngine::_diag';
+		wfProfileIn( $fname );
+		$flip = false;
+
+		if ($xlim - $xoff > $ylim - $yoff) {
+			// Things seems faster (I'm not sure I understand why)
+				// when the shortest sequence in X.
+				$flip = true;
+			list ($xoff, $xlim, $yoff, $ylim)
+			= array( $yoff, $ylim, $xoff, $xlim);
 		}
 
-	if ($flip)
-		for ($i = $ylim - 1; $i >= $yoff; $i--)
-		$ymatches[$this->xv[$i]][] = $i;
-	else
-		for ($i = $ylim - 1; $i >= $yoff; $i--)
-		$ymatches[$this->yv[$i]][] = $i;
-
-	$this->lcs = 0;
-	$this->seq[0]= $yoff - 1;
-	$this->in_seq = array();
-	$ymids[0] = array();
+		if ($flip)
+			for ($i = $ylim - 1; $i >= $yoff; $i--)
+				$ymatches[$this->xv[$i]][] = $i;
+		else
+			for ($i = $ylim - 1; $i >= $yoff; $i--)
+				$ymatches[$this->yv[$i]][] = $i;
 	
-	$numer = $xlim - $xoff + $nchunks - 1;
-	$x = $xoff;
-	for ($chunk = 0; $chunk < $nchunks; $chunk++) {
-		if ($chunk > 0)
-		for ($i = 0; $i <= $this->lcs; $i++)
-			$ymids[$i][$chunk-1] = $this->seq[$i];
-
-		$x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
-		for ( ; $x < $x1; $x++) {
+		$this->lcs = 0;
+		$this->seq[0]= $yoff - 1;
+		$this->in_seq = array();
+		$ymids[0] = array();
+	
+		$numer = $xlim - $xoff + $nchunks - 1;
+		$x = $xoff;
+		for ($chunk = 0; $chunk < $nchunks; $chunk++) {
+			wfProfileIn( "$fname-chunk" );
+			if ($chunk > 0)
+				for ($i = 0; $i <= $this->lcs; $i++)
+					$ymids[$i][$chunk-1] = $this->seq[$i];
+	
+			$x1 = $xoff + (int)(($numer + ($xlim-$xoff)*$chunk) / $nchunks);
+			for ( ; $x < $x1; $x++) {
 				$line = $flip ? $this->yv[$x] : $this->xv[$x];
-				if (empty($ymatches[$line]))
-			continue;
-		$matches = $ymatches[$line];
+					if (empty($ymatches[$line]))
+						continue;
+				$matches = $ymatches[$line];
 				reset($matches);
-		while (list ($junk, $y) = each($matches))
-			if (empty($this->in_seq[$y])) {
-			$k = $this->_lcs_pos($y);
-			USE_ASSERTS && assert($k > 0);
-			$ymids[$k] = $ymids[$k-1];
-			break;
+				while (list ($junk, $y) = each($matches))
+					if (empty($this->in_seq[$y])) {
+						$k = $this->_lcs_pos($y);
+						USE_ASSERTS && 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]);
-			// Optimization: this is a common case:
-			//	next match is just replacing previous match.
-			$this->in_seq[$this->seq[$k]] = false;
-			$this->seq[$k] = $y;
-			$this->in_seq[$y] = 1;
-					}
-			else if (empty($this->in_seq[$y])) {
-			$k = $this->_lcs_pos($y);
-			USE_ASSERTS && assert($k > 0);
-			$ymids[$k] = $ymids[$k-1];
+				while (list ($junk, $y) = each($matches)) {
+					if ($y > $this->seq[$k-1]) {
+						USE_ASSERTS && 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;
+						$this->seq[$k] = $y;
+						$this->in_seq[$y] = 1;
+					} else if (empty($this->in_seq[$y])) {
+						$k = $this->_lcs_pos($y);
+						USE_ASSERTS && assert($k > 0);
+						$ymids[$k] = $ymids[$k-1];
 					}
 				}
 			}
+			wfProfileOut( "$fname-chunk" );
 		}
-
-	$seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
-	$ymid = $ymids[$this->lcs];
-	for ($n = 0; $n < $nchunks - 1; $n++) {
-		$x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
-		$y1 = $ymid[$n] + 1;
-		$seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
+	
+		$seps[] = $flip ? array($yoff, $xoff) : array($xoff, $yoff);
+		$ymid = $ymids[$this->lcs];
+		for ($n = 0; $n < $nchunks - 1; $n++) {
+			$x1 = $xoff + (int)(($numer + ($xlim - $xoff) * $n) / $nchunks);
+			$y1 = $ymid[$n] + 1;
+			$seps[] = $flip ? array($y1, $x1) : array($x1, $y1);
 		}
-	$seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
-
-	return array($this->lcs, $seps);
+		$seps[] = $flip ? array($ylim, $xlim) : array($xlim, $ylim);
+	
+		wfProfileOut( $fname );
+		return array($this->lcs, $seps);
 	}
 
 	function _lcs_pos ($ypos) {
-	$end = $this->lcs;
-	if ($end == 0 || $ypos > $this->seq[$end]) {
-		$this->seq[++$this->lcs] = $ypos;
-		$this->in_seq[$ypos] = 1;
-		return $this->lcs;
+		$fname = '_DiffEngine::_lcs_pos';
+		wfProfileIn( $fname );
+		
+		$end = $this->lcs;
+		if ($end == 0 || $ypos > $this->seq[$end]) {
+			$this->seq[++$this->lcs] = $ypos;
+			$this->in_seq[$ypos] = 1;
+			wfProfileOut( $fname );
+			return $this->lcs;
 		}
 
-	$beg = 1;
-	while ($beg < $end) {
-		$mid = (int)(($beg + $end) / 2);
-		if ( $ypos > $this->seq[$mid] )
-		$beg = $mid + 1;
-		else
-		$end = $mid;
+		$beg = 1;
+		while ($beg < $end) {
+			$mid = (int)(($beg + $end) / 2);
+			if ( $ypos > $this->seq[$mid] )
+				$beg = $mid + 1;
+			else
+				$end = $mid;
 		}
-
-	USE_ASSERTS && assert($ypos != $this->seq[$end]);
-
-	$this->in_seq[$this->seq[$end]] = false;
-	$this->seq[$end] = $ypos;
-	$this->in_seq[$ypos] = 1;
-	return $end;
+	
+		USE_ASSERTS && assert($ypos != $this->seq[$end]);
+	
+		$this->in_seq[$this->seq[$end]] = false;
+		$this->seq[$end] = $ypos;
+		$this->in_seq[$ypos] = 1;
+		wfProfileOut( $fname );
+		return $end;
 	}
 
 	/* Find LCS of two sequences.
@@ -498,48 +670,51 @@ class _DiffEngine
 	 * All line numbers are origin-0 and discarded lines are not counted.
 	 */
 	function _compareseq ($xoff, $xlim, $yoff, $ylim) {
-	// Slide down the bottom initial diagonal.
-	while ($xoff < $xlim && $yoff < $ylim
+		$fname = '_DiffEngine::_compareseq';
+		wfProfileIn( $fname );
+		
+		// Slide down the bottom initial diagonal.
+		while ($xoff < $xlim && $yoff < $ylim
 			   && $this->xv[$xoff] == $this->yv[$yoff]) {
-		++$xoff;
-		++$yoff;
+			++$xoff;
+			++$yoff;
 		}
 
-	// Slide up the top initial diagonal.
-	while ($xlim > $xoff && $ylim > $yoff
+		// Slide up the top initial diagonal.
+		while ($xlim > $xoff && $ylim > $yoff
 			   && $this->xv[$xlim - 1] == $this->yv[$ylim - 1]) {
-		--$xlim;
-		--$ylim;
+			--$xlim;
+			--$ylim;
 		}
 
-	if ($xoff == $xlim || $yoff == $ylim)
-		$lcs = 0;
-	else {
-		// This is ad hoc but seems to work well.
-		//$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
-		//$nchunks = max(2,min(8,(int)$nchunks));
-		$nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
-		list ($lcs, $seps)
-		= $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
+		if ($xoff == $xlim || $yoff == $ylim)
+			$lcs = 0;
+		else {
+			// This is ad hoc but seems to work well.
+			//$nchunks = sqrt(min($xlim - $xoff, $ylim - $yoff) / 2.5);
+			//$nchunks = max(2,min(8,(int)$nchunks));
+			$nchunks = min(7, $xlim - $xoff, $ylim - $yoff) + 1;
+			list ($lcs, $seps)
+			= $this->_diag($xoff,$xlim,$yoff, $ylim,$nchunks);
 		}
 
-	if ($lcs == 0) {
-		// X and Y sequences have no common subsequence:
-		// mark all changed.
-		while ($yoff < $ylim)
-		$this->ychanged[$this->yind[$yoff++]] = 1;
-		while ($xoff < $xlim)
-		$this->xchanged[$this->xind[$xoff++]] = 1;
-		}
-	else {
-		// Use the partitions to split this problem into subproblems.
-		reset($seps);
-		$pt1 = $seps[0];
-		while ($pt2 = next($seps)) {
-		$this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
-		$pt1 = $pt2;
+		if ($lcs == 0) {
+			// X and Y sequences have no common subsequence:
+			// mark all changed.
+			while ($yoff < $ylim)
+				$this->ychanged[$this->yind[$yoff++]] = 1;
+			while ($xoff < $xlim)
+				$this->xchanged[$this->xind[$xoff++]] = 1;
+		} else {
+			// Use the partitions to split this problem into subproblems.
+			reset($seps);
+			$pt1 = $seps[0];
+			while ($pt2 = next($seps)) {
+				$this->_compareseq ($pt1[0], $pt2[0], $pt1[1], $pt2[1]);
+				$pt1 = $pt2;
 			}
 		}
+		wfProfileOut( $fname );
 	}
 
 	/* Adjust inserts/deletes of identical lines to join changes
@@ -555,117 +730,124 @@ class _DiffEngine
 	 * This is extracted verbatim from analyze.c (GNU diffutils-2.7).
 	 */
 	function _shift_boundaries ($lines, &$changed, $other_changed) {
-	$i = 0;
-	$j = 0;
-
-	USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
-	$len = sizeof($lines);
-	$other_len = sizeof($other_changed);
-
-	while (1) {
-		/*
-		 * Scan forwards to find beginning of another run of changes.
-		 * Also keep track of the corresponding point in the other file.
-		 *
-		 * Throughout this code, $i and $j are adjusted together so that
-		 * the first $i elements of $changed and the first $j elements
-		 * of $other_changed both contain the same number of zeros
-		 * (unchanged lines).
-		 * Furthermore, $j is always kept so that $j == $other_len or
-		 * $other_changed[$j] == false.
-		 */
-		while ($j < $other_len && $other_changed[$j])
-		$j++;
-		
-		while ($i < $len && ! $changed[$i]) {
-		USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
-		$i++; $j++;
-		while ($j < $other_len && $other_changed[$j])
-			$j++;
+		$fname = '_DiffEngine::_shift_boundaries';
+		wfProfileIn( $fname );
+		$i = 0;
+		$j = 0;
+	
+		USE_ASSERTS && assert('sizeof($lines) == sizeof($changed)');
+		$len = sizeof($lines);
+		$other_len = sizeof($other_changed);
+	
+		while (1) {
+			/*
+			 * Scan forwards to find beginning of another run of changes.
+			 * Also keep track of the corresponding point in the other file.
+			 *
+			 * Throughout this code, $i and $j are adjusted together so that
+			 * the first $i elements of $changed and the first $j elements
+			 * of $other_changed both contain the same number of zeros
+			 * (unchanged lines).
+			 * Furthermore, $j is always kept so that $j == $other_len or
+			 * $other_changed[$j] == false.
+			 */
+			while ($j < $other_len && $other_changed[$j])
+				$j++;
+	
+			while ($i < $len && ! $changed[$i]) {
+				USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
+				$i++; $j++;
+				while ($j < $other_len && $other_changed[$j])
+					$j++;
 			}
 			
-		if ($i == $len)
-		break;
-
-		$start = $i;
-
-		// Find the end of this run of changes.
-		while (++$i < $len && $changed[$i])
-		continue;
-
-		do {
-		/*
-		 * Record the length of this run of changes, so that
-		 * we can later determine whether the run has grown.
-		 */
-		$runlength = $i - $start;
-
-		/*
-		 * Move the changed region back, so long as the
-		 * previous unchanged line matches the last changed one.
-		 * This merges with previous changed regions.
-		 */
-		while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
-			$changed[--$start] = 1;
-			$changed[--$i] = false;
-			while ($start > 0 && $changed[$start - 1])
-			$start--;
-			USE_ASSERTS && assert('$j > 0');
-			while ($other_changed[--$j])
-			continue;
-			USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
+			if ($i == $len)
+				break;
+			
+			$start = $i;
+			
+			// Find the end of this run of changes.
+			while (++$i < $len && $changed[$i])
+				continue;
+			
+			do {
+				/*
+				 * Record the length of this run of changes, so that
+				 * we can later determine whether the run has grown.
+				 */
+				$runlength = $i - $start;
+				
+				/*
+				 * Move the changed region back, so long as the
+				 * previous unchanged line matches the last changed one.
+				 * This merges with previous changed regions.
+				 */
+				while ($start > 0 && $lines[$start - 1] == $lines[$i - 1]) {
+					$changed[--$start] = 1;
+					$changed[--$i] = false;
+					while ($start > 0 && $changed[$start - 1])
+						$start--;
+					USE_ASSERTS && assert('$j > 0');
+					while ($other_changed[--$j])
+						continue;
+					USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 				}
-
-		/*
-		 * Set CORRESPONDING to the end of the changed run, at the last
-		 * point where it corresponds to a changed run in the other file.
-		 * CORRESPONDING == LEN means no such point has been found.
-		 */
-		$corresponding = $j < $other_len ? $i : $len;
-
-		/*
-		 * Move the changed region forward, so long as the
-		 * first changed line matches the following unchanged one.
-		 * This merges with following changed regions.
-		 * Do this second, so that if there are no merges,
-		 * the changed region is moved forward as far as possible.
-		 */
-		while ($i < $len && $lines[$start] == $lines[$i]) {
-			$changed[$start++] = false;
-			$changed[$i++] = 1;
-			while ($i < $len && $changed[$i])
-			$i++;
-
-			USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
-			$j++;
-			if ($j < $other_len && $other_changed[$j]) {
-			$corresponding = $i;
-			while ($j < $other_len && $other_changed[$j])
-				$j++;
+	
+				/*
+				 * Set CORRESPONDING to the end of the changed run, at the last
+				 * point where it corresponds to a changed run in the other file.
+				 * CORRESPONDING == LEN means no such point has been found.
+				 */
+				$corresponding = $j < $other_len ? $i : $len;
+		
+				/*
+				 * Move the changed region forward, so long as the
+				 * first changed line matches the following unchanged one.
+				 * This merges with following changed regions.
+				 * Do this second, so that if there are no merges,
+				 * the changed region is moved forward as far as possible.
+				 */
+				while ($i < $len && $lines[$start] == $lines[$i]) {
+					$changed[$start++] = false;
+					$changed[$i++] = 1;
+					while ($i < $len && $changed[$i])
+						$i++;
+		
+					USE_ASSERTS && assert('$j < $other_len && ! $other_changed[$j]');
+					$j++;
+					if ($j < $other_len && $other_changed[$j]) {
+						$corresponding = $i;
+						while ($j < $other_len && $other_changed[$j])
+							$j++;
 					}
 				}
 			} while ($runlength != $i - $start);
-
-		/*
-		 * If possible, move the fully-merged run of changes
-		 * back to a corresponding run in the other file.
-		 */
-		while ($corresponding < $i) {
-		$changed[--$start] = 1;
-		$changed[--$i] = 0;
-		USE_ASSERTS && assert('$j > 0');
-		while ($other_changed[--$j])
-			continue;
-		USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
+	
+			/*
+			 * If possible, move the fully-merged run of changes
+			 * back to a corresponding run in the other file.
+			 */
+			while ($corresponding < $i) {
+				$changed[--$start] = 1;
+				$changed[--$i] = 0;
+				USE_ASSERTS && assert('$j > 0');
+				while ($other_changed[--$j])
+					continue;
+				USE_ASSERTS && assert('$j >= 0 && !$other_changed[$j]');
 			}
 		}
+		wfProfileOut( $fname );
 	}
 }
 
 /**
  * Class representing a 'diff' between two sequences of strings.
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
  */
-class Diff 
+class Diff
 {
 	var $edits;
 
@@ -694,12 +876,12 @@ class Diff
 	 *				  original diff.
 	 */
 	function reverse () {
-	$rev = $this;
+		$rev = $this;
 		$rev->edits = array();
 		foreach ($this->edits as $edit) {
 			$rev->edits[] = $edit->reverse();
 		}
-	return $rev;
+		return $rev;
 	}
 
 	/**
@@ -714,7 +896,7 @@ class Diff
 		}
 		return true;
 	}
-  
+
 	/**
 	 * Compute the length of the Longest Common Subsequence (LCS).
 	 *
@@ -723,12 +905,12 @@ class Diff
 	 * @return int The length of the LCS.
 	 */
 	function lcs () {
-	$lcs = 0;
+		$lcs = 0;
 		foreach ($this->edits as $edit) {
 			if ($edit->type == 'copy')
 				$lcs += sizeof($edit->orig);
 		}
-	return $lcs;
+		return $lcs;
 	}
 
 	/**
@@ -741,7 +923,7 @@ class Diff
 	 */
 	function orig() {
 		$lines = array();
-		
+
 		foreach ($this->edits as $edit) {
 			if ($edit->orig)
 				array_splice($lines, sizeof($lines), 0, $edit->orig);
@@ -759,7 +941,7 @@ class Diff
 	 */
 	function closing() {
 		$lines = array();
-		
+
 		foreach ($this->edits as $edit) {
 			if ($edit->closing)
 				array_splice($lines, sizeof($lines), 0, $edit->closing);
@@ -768,11 +950,13 @@ class Diff
 	}
 
 	/**
-	 * Check a Diff for validity. 
+	 * Check a Diff for validity.
 	 *
 	 * This is here only for debugging purposes.
 	 */
 	function _check ($from_lines, $to_lines) {
+		$fname = 'Diff::_check';
+		wfProfileIn( $fname );
 		if (serialize($from_lines) != serialize($this->orig()))
 			trigger_error("Reconstructed original doesn't match", E_USER_ERROR);
 		if (serialize($to_lines) != serialize($this->closing()))
@@ -793,15 +977,19 @@ class Diff
 		}
 
 		$lcs = $this->lcs();
-		trigger_error("Diff okay: LCS = $lcs", E_USER_NOTICE);
+		trigger_error('Diff okay: LCS = '.$lcs, E_USER_NOTICE);
+		wfProfileOut( $fname );
 	}
 }
-			
+
 /**
  * FIXME: bad name.
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
  */
-class MappedDiff
-extends Diff
+class MappedDiff extends Diff
 {
 	/**
 	 * Constructor.
@@ -828,10 +1016,12 @@ extends Diff
 	 */
 	function MappedDiff($from_lines, $to_lines,
 						$mapped_from_lines, $mapped_to_lines) {
-
+		$fname = 'MappedDiff::MappedDiff';
+		wfProfileIn( $fname );
+		
 		assert(sizeof($from_lines) == sizeof($mapped_from_lines));
 		assert(sizeof($to_lines) == sizeof($mapped_to_lines));
-		
+
 		$this->Diff($mapped_from_lines, $mapped_to_lines);
 
 		$xi = $yi = 0;
@@ -841,13 +1031,14 @@ extends Diff
 				$orig = array_slice($from_lines, $xi, sizeof($orig));
 				$xi += sizeof($orig);
 			}
-			
+
 			$closing = &$this->edits[$i]->closing;
 			if (is_array($closing)) {
 				$closing = array_slice($to_lines, $yi, sizeof($closing));
 				$yi += sizeof($closing);
 			}
 		}
+		wfProfileOut( $fname );
 	}
 }
 
@@ -857,6 +1048,10 @@ extends Diff
  * This class formats the diff in classic diff format.
  * It is intended that this class be customized via inheritance,
  * to obtain fancier outputs.
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
  */
 class DiffFormatter
 {
@@ -883,6 +1078,8 @@ class DiffFormatter
 	 * @return string The formatted output.
 	 */
 	function format($diff) {
+		$fname = 'DiffFormatter::format';
+		wfProfileIn( $fname );
 
 		$xi = $yi = 1;
 		$block = false;
@@ -935,10 +1132,14 @@ class DiffFormatter
 						  $y0, $yi - $y0,
 						  $block);
 
-		return $this->_end_diff();
+		$end = $this->_end_diff();
+		wfProfileOut( $fname );
+		return $end;
 	}
 
 	function _block($xbeg, $xlen, $ybeg, $ylen, &$edits) {
+		$fname = 'DiffFormatter::_block';
+		wfProfileIn( $fname );
 		$this->_start_block($this->_block_header($xbeg, $xlen, $ybeg, $ylen));
 		foreach ($edits as $edit) {
 			if ($edit->type == 'copy')
@@ -950,9 +1151,10 @@ class DiffFormatter
 			elseif ($edit->type == 'change')
 				$this->_changed($edit->orig, $edit->closing);
 			else
-				trigger_error("Unknown edit type", E_USER_ERROR);
+				trigger_error('Unknown edit type', E_USER_ERROR);
 		}
 		$this->_end_block();
+		wfProfileOut( $fname );
 	}
 
 	function _start_diff() {
@@ -973,11 +1175,11 @@ class DiffFormatter
 
 		return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg;
 	}
-	
+
 	function _start_block($header) {
 		echo $header;
 	}
-	
+
 	function _end_block() {
 	}
 
@@ -985,16 +1187,16 @@ class DiffFormatter
 		foreach ($lines as $line)
 			echo "$prefix $line\n";
 	}
-	
+
 	function _context($lines) {
 		$this->_lines($lines);
 	}
 
 	function _added($lines) {
-		$this->_lines($lines, ">");
+		$this->_lines($lines, '>');
 	}
 	function _deleted($lines) {
-		$this->_lines($lines, "<");
+		$this->_lines($lines, '<');
 	}
 
 	function _changed($orig, $closing) {
@@ -1007,11 +1209,17 @@ class DiffFormatter
 
 /**
  *	Additions by Axel Boldt follow, partly taken from diff.php, phpwiki-1.3.3
- * 
+ *
  */
 
-define('NBSP', "\xA0");			// iso-8859-x non-breaking space.
+define('NBSP', '&#160;');			// iso-8859-x non-breaking space.
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class _HWLDF_WordAccumulator {
 	function _HWLDF_WordAccumulator () {
 		$this->_lines = array();
@@ -1022,22 +1230,26 @@ class _HWLDF_WordAccumulator {
 
 	function _flushGroup ($new_tag) {
 		if ($this->_group !== '') {
-	  if ($this->_tag == 'mark') 
-			$this->_line .= "<font color=\"red\">$this->_group</font>";
-	  else
-		$this->_line .= $this->_group;
-	}
+			if ($this->_tag == 'mark')
+				$this->_line .= '<span class="diffchange">' .
+					htmlspecialchars ( $this->_group ) . '</span>';
+			else
+				$this->_line .= htmlspecialchars ( $this->_group );
+		}
 		$this->_group = '';
 		$this->_tag = $new_tag;
 	}
-	
+
 	function _flushLine ($new_tag) {
 		$this->_flushGroup($new_tag);
 		if ($this->_line != '')
-			$this->_lines[] = $this->_line;
+			array_push ( $this->_lines, $this->_line );
+		else
+			# make empty lines visible by inserting an NBSP
+			array_push ( $this->_lines, NBSP );
 		$this->_line = '';
 	}
-				
+
 	function addWords ($words, $tag = '') {
 		if ($tag != $this->_tag)
 			$this->_flushGroup($tag);
@@ -1047,7 +1259,6 @@ class _HWLDF_WordAccumulator {
 			if ($word == '')
 				continue;
 			if ($word[0] == "\n") {
-				$this->_group .= NBSP;
 				$this->_flushLine($tag);
 				$word = substr($word, 1);
 			}
@@ -1062,56 +1273,79 @@ class _HWLDF_WordAccumulator {
 	}
 }
 
+/**
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
+ */
 class WordLevelDiff extends MappedDiff
 {
 	function WordLevelDiff ($orig_lines, $closing_lines) {
+		$fname = 'WordLevelDiff::WordLevelDiff';
+		wfProfileIn( $fname );
+		
 		list ($orig_words, $orig_stripped) = $this->_split($orig_lines);
 		list ($closing_words, $closing_stripped) = $this->_split($closing_lines);
 
-		
+
 		$this->MappedDiff($orig_words, $closing_words,
 						  $orig_stripped, $closing_stripped);
+		wfProfileOut( $fname );
 	}
 
 	function _split($lines) {
-		// FIXME: fix POSIX char class.
-#		 if (!preg_match_all('/ ( [^\S\n]+ | [[:alnum:]]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
+		$fname = 'WordLevelDiff::_split';
+		wfProfileIn( $fname );
 		if (!preg_match_all('/ ( [^\S\n]+ | [0-9_A-Za-z\x80-\xff]+ | . ) (?: (?!< \n) [^\S\n])? /xs',
 							implode("\n", $lines),
 							$m)) {
+			wfProfileOut( $fname );
 			return array(array(''), array(''));
 		}
+		wfProfileOut( $fname );
 		return array($m[0], $m[1]);
 	}
 
 	function orig () {
+		$fname = 'WordLevelDiff::orig';
+		wfProfileIn( $fname );
 		$orig = new _HWLDF_WordAccumulator;
-		
+
 		foreach ($this->edits as $edit) {
 			if ($edit->type == 'copy')
 				$orig->addWords($edit->orig);
 			elseif ($edit->orig)
 				$orig->addWords($edit->orig, 'mark');
 		}
-		return $orig->getLines();
+		$lines = $orig->getLines();
+		wfProfileOut( $fname );
+		return $lines;
 	}
 
 	function closing () {
+		$fname = 'WordLevelDiff::closing';
+		wfProfileIn( $fname );
 		$closing = new _HWLDF_WordAccumulator;
-		
+
 		foreach ($this->edits as $edit) {
 			if ($edit->type == 'copy')
 				$closing->addWords($edit->closing);
 			elseif ($edit->closing)
 				$closing->addWords($edit->closing, 'mark');
 		}
-		return $closing->getLines();
+		$lines = $closing->getLines();
+		wfProfileOut( $fname );
+		return $lines;
 	}
 }
 
 /**
  *	Wikipedia Table style diff formatter.
- * 
+ * @todo document
+ * @access private
+ * @package MediaWiki 
+ * @subpackage DifferenceEngine
  */
 class TableDiffFormatter extends DiffFormatter
 {
@@ -1119,81 +1353,89 @@ class TableDiffFormatter extends DiffFormatter
 		$this->leading_context_lines = 2;
 		$this->trailing_context_lines = 2;
 	}
-	
+
 	function _block_header( $xbeg, $xlen, $ybeg, $ylen ) {
-		$l1 = wfMsg( "lineno", $xbeg );
-		$l2 = wfMsg( "lineno", $ybeg );
+		$l1 = wfMsg( 'lineno', $xbeg );
+		$l2 = wfMsg( 'lineno', $ybeg );
 
-		$r = "<tr><td colspan='2' align='left'><strong>{$l1}</strong></td>\n" .
-		  "<td colspan='2' align='left'><strong>{$l2}</strong></td></tr>\n";
+		$r = '<tr><td colspan="2" align="left"><strong>'.$l1."</strong></td>\n" .
+		  '<td colspan="2" align="left"><strong>'.$l2."</strong></td></tr>\n";
 		return $r;
 	}
 
 	function _start_block( $header ) {
 		global $wgOut;
-		$wgOut->addHTML( $header );
+		echo $header;
 	}
 
 	function _end_block() {
 	}
 
-	function _lines( $lines, $prefix=' ', $color="white" ) {
+	function _lines( $lines, $prefix=' ', $color='white' ) {
 	}
 
+	# HTML-escape parameter before calling this
 	function addedLine( $line ) {
-		return "<td>+</td><td class='diff-addedline'>" .
-		  "<small>{$line}</small></td>";
+		return "<td>+</td><td class='diff-addedline'>{$line}</td>";
 	}
 
+	# HTML-escape parameter before calling this
 	function deletedLine( $line ) {
-		return "<td>-</td><td class='diff-deletedline'>" .
-		  "<small>{$line}</small></td>";
+		return "<td>-</td><td class='diff-deletedline'>{$line}</td>";
 	}
 
-	function emptyLine() {
-		return "<td colspan='2'>&nbsp;</td>";
+	# HTML-escape parameter before calling this
+	function contextLine( $line ) {
+		return "<td> </td><td class='diff-context'>{$line}</td>";
 	}
 
-	function contextLine( $line ) {
-		return "<td> </td><td class='diff-context'><small>{$line}</small></td>";
+	function emptyLine() {
+		return '<td colspan="2">&nbsp;</td>';
 	}
-	
-	function _added($lines) {
-		global $wgOut;
+
+	function _added( $lines ) {
 		foreach ($lines as $line) {
-			$wgOut->addHTML( "<tr>" . $this->emptyLine() .
-			  $this->addedLine( $line ) . "</tr>\n" );
+			echo '<tr>' . $this->emptyLine() .
+				$this->addedLine( htmlspecialchars ( $line ) ) . "</tr>\n";
 		}
 	}
 
 	function _deleted($lines) {
-		global $wgOut;
 		foreach ($lines as $line) {
-			$wgOut->addHTML( "<tr>" . $this->deletedLine( $line ) .
-			  $this->emptyLine() . "</tr>\n" );
+			echo '<tr>' . $this->deletedLine( htmlspecialchars ( $line ) ) .
+			  $this->emptyLine() . "</tr>\n";
 		}
 	}
 
 	function _context( $lines ) {
-		global $wgOut;
 		foreach ($lines as $line) {
-			$wgOut->addHTML( "<tr>" . $this->contextLine( $line ) .
-			  $this->contextLine( $line ) . "</tr>\n" );
+			echo '<tr>' .
+				$this->contextLine( htmlspecialchars ( $line ) ) .
+				$this->contextLine( htmlspecialchars ( $line ) ) . "</tr>\n";
 		}
 	}
 
 	function _changed( $orig, $closing ) {
-		global $wgOut;
+		$fname = 'TableDiffFormatter::_changed';
+		wfProfileIn( $fname );
+		
 		$diff = new WordLevelDiff( $orig, $closing );
 		$del = $diff->orig();
 		$add = $diff->closing();
 
+		# Notice that WordLevelDiff returns HTML-escaped output.
+		# Hence, we will be calling addedLine/deletedLine without HTML-escaping.
+
 		while ( $line = array_shift( $del ) ) {
 			$aline = array_shift( $add );
-			$wgOut->addHTML( "<tr>" . $this->deletedLine( $line ) .
-			  $this->addedLine( $aline ) . "</tr>\n" );
+			echo '<tr>' . $this->deletedLine( $line ) .
+				$this->addedLine( $aline ) . "</tr>\n";
+		}
+		foreach ($add as $line) {	# If any leftovers
+			echo '<tr>' . $this->emptyLine() .
+				$this->addedLine( $line ) . "</tr>\n";
 		}
-		$this->_added( $add ); # If any leftovers
+		wfProfileOut( $fname );
 	}
 }