better whitespace preserve fix in diffs

Ignore-this: ce1092e86cbb4911e285377233b89aa0

darcs-hash:20091119085441-6e07b-79f74d6349df87625aaaba919664879fcc440244.gz

inc/DifferenceEngine.php

@@ -978,7 +978,8 @@ class TableDiffFormatter extends DiffFormatter
 
   function _pre($text){
     $text = htmlspecialchars($text);
-    $text = str_replace(' ',' ',$text);
+    $text = str_replace('  ','  ',$text);
+    if($text{0} == ' ') $text = ' '.substr($text,1);
     return $text;
   }
 
@@ -1002,13 +1003,15 @@ class TableDiffFormatter extends DiffFormatter
   }
 
   function addedLine( $line ) {
-    $line = str_replace(' ',' ',$line);
+    $line = str_replace('  ','  ',$line);
+    if($line{0} == ' ') $line = ' '.substr($line,1);
     return '<td>+</td><td class="diff-addedline">' .
       $line.'</td>';
   }
 
   function deletedLine( $line ) {
-    $line = str_replace(' ','&nbsp;',$line);
+    $line = str_replace('  ',' &nbsp;',$line);
+    if($line{0} == ' ') $line = '&nbsp;'.substr($line,1);
     return '<td>-</td><td class="diff-deletedline">' .
       $line.'</td>';
   }
@@ -1019,7 +1022,8 @@ class TableDiffFormatter extends DiffFormatter
   }
 
   function contextLine( $line ) {
-    $line = str_replace(' ','&nbsp;',$line);
+    $line = str_replace('  ',' &nbsp;',$line);
+    if($line{0} == ' ') $line = '&nbsp;'.substr($line,1);
     return '<td> </td><td class="diff-context">'.$line.'</td>';
   }