From 3fca385791f1bd1390d0c66e820105a57cf977d2 Mon Sep 17 00:00:00 2001
From: Zheng Zhu <zhengzhu@users.mediawiki.org>
Date: Sun, 5 Dec 2004 02:17:21 +0000
Subject: [PATCH] Treat each Chinese character as a single word when diffing,
 and glue them back together afterward. This gives much more readable diff for
 zh.

---
 includes/DifferenceEngine.php | 13 ++++++++-----
 languages/Language.php        | 11 ++++++++++-
 languages/LanguageLatin1.php  |  8 ++++++++
 languages/LanguageZh.php      | 15 ++++++++++++++-
 4 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/includes/DifferenceEngine.php b/includes/DifferenceEngine.php
index a4793f7703..4c6017ef43 100644
--- a/includes/DifferenceEngine.php
+++ b/includes/DifferenceEngine.php
@@ -215,7 +215,7 @@ class DifferenceEngine {
 	}
 	
 	function getDiff( $otext, $ntext, $otitle, $ntitle ) {
-		global $wgUseExternalDiffEngine;
+		global $wgUseExternalDiffEngine, $wgContLang;
 		$out = "
 			<table border='0' width='98%' cellpadding='0' cellspacing='4' class='diff'>
 			<tr>
@@ -223,7 +223,9 @@ class DifferenceEngine {
 				<td colspan='2' width='50%' align='center' class='diff-ntitle'>{$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
@@ -232,15 +234,16 @@ class DifferenceEngine {
 			if( !function_exists( 'wikidiff_do_diff' ) ) {
 				dl('php_wikidiff.so');
 			}
-			$out .= wikidiff_do_diff( $otext, $ntext, 2 );
+			$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();
-			$out .= $formatter->format( $diffs );
+			$difftext = $formatter->format( $diffs );
 		}
-		$out .= "</table>\n";
+		$difftext = $wgContLang->unsegmentForDiff($difftext);
+		$out .= $difftext."</table>\n";
 		return $out;
 	}
 
diff --git a/languages/Language.php b/languages/Language.php
index 55e37eae69..98abf3cf39 100644
--- a/languages/Language.php
+++ b/languages/Language.php
@@ -2038,7 +2038,16 @@ class Language {
 		return $word;
 	}
 
-	
+	# languages like Chinese need to be segmented in order for the diff
+	# to be of any use
+	function segmentForDiff( $text ) {
+		return $text;
+	}
+	# and unsegment to show the result
+	function unsegmentForDiff( $text ) {
+		return $text;
+	}
+
 	# convert text to different variants of a language. the automatic
 	# conversion is done in autoConvert(). here we parse the text 
 	# marked with -{}-, which specifies special conversions of the 
diff --git a/languages/LanguageLatin1.php b/languages/LanguageLatin1.php
index e031007e4d..9a54330bd3 100644
--- a/languages/LanguageLatin1.php
+++ b/languages/LanguageLatin1.php
@@ -263,6 +263,14 @@ class LanguageLatin1 {
 		return $this->lang->getPreferredVariant();
 	}
 
+	function segmentForDiff( $text ) {
+		return $text;
+	}
+
+	function unsegmentForDiff( $text ) {
+		return $text;
+	}
+
 	function convert( $text, $isTitle=false ) {
 		return utf8_decode( $this->lang->convert( utf8_encode( $text ), $isTitle ) );
 	}
diff --git a/languages/LanguageZh.php b/languages/LanguageZh.php
index e24af2649d..38cdcb7e55 100644
--- a/languages/LanguageZh.php
+++ b/languages/LanguageZh.php
@@ -55,7 +55,20 @@ class LanguageZh extends LanguageZh_cn {
 		return $this->mZhLanguageCode;
 	}
 	
-	
+	# this should give much better diff info
+	function segmentForDiff( $text ) {
+		return preg_replace(
+			"/([\\xc0-\\xff][\\x80-\\xbf]*)/e",
+			"' ' .\"$1\"", $text);
+	}
+
+	function unsegmentForDiff( $text ) {
+		return preg_replace(
+			"/ ([\\xc0-\\xff][\\x80-\\xbf]*)/e",
+			"\"$1\"", $text);
+	}
+
+
 	
 	function autoConvert($text, $toVariant=false) {
 		if(!$toVariant) 
-- 
2.20.1