--- diff.inc.php.orig	Sun Oct 31 14:21:47 2004
+++ diff.inc.php	Sun Feb 20 23:27:42 2005
@@ -16,6 +16,7 @@
 	$action = isset($vars['action']) ? $vars['action'] : '';
 	switch ($action) {
 		case 'delete': $retval = plugin_diff_delete($page);	break;
+		case 'undo':   $retval = plugin_diff_undo($page);	break;
 		default:       $retval = plugin_diff_view($page);	break;
 	}
 	return $retval;
@@ -27,6 +28,7 @@
 	global $script, $hr;
 	global $_msg_notfound, $_msg_goto, $_msg_deleted, $_msg_addline, $_msg_delline, $_title_diff;
 	global $_title_diff_delete;
+	global $_title_diff_undo;
 
 	$r_page = rawurlencode($page);
 	$s_page = htmlspecialchars($page);
@@ -50,6 +52,7 @@
 		$diffdata = preg_replace('/^(\+)(.*)$/m', '<span class="diff_added"  > $2</span>', $diffdata);
 		$menu[] = "<li><a href=\"$script?cmd=diff&amp;action=delete&amp;page=$r_page\">" .
 			str_replace('$1', $s_page, $_title_diff_delete) . '</a></li>';
+		$menu[] = "<li><a href=\"$script?cmd=diff&amp;action=undo&amp;page=$r_page\">$_title_diff_undo</a></li>";
 		$msg = "<pre>$diffdata</pre>\n";
 	}
 	else if ($is_page) {
@@ -111,5 +114,90 @@
 EOD;
 
 	return array('msg'=>$_title_diff_delete, 'body'=>$body);
+}
+
+// 変更点を元に戻す
+function plugin_diff_undo($page)
+{
+	global $script, $vars;
+	global $_title_diff_undo;
+	global $_msg_diff_adminpass, $_btn_undo, $_msg_invalidpass;
+
+	$filename = DIFF_DIR . encode($page) . '.txt';
+	$body = '';
+	if (! is_pagename($page))     $body = "Invalid page name";
+	if (! file_exists($filename)) $body = make_pagelink($page) . "'s diff seems not found";
+	if ($body) return array('msg'=>$_title_diff_undo, 'body'=>$body);
+
+	if (isset($vars['pass'])) {
+		if (pkwk_login($vars['pass'])) {
+
+			if (file_exists($filename)) {
+				$postdata = '';
+				$diffdata = file($filename);
+				foreach($diffdata as $_line) {
+					$match = array();
+					if(preg_match('/^[\s\-](.*)$/',$_line,$match)) {
+						$postdata .= $match[1] . "\n";
+					}
+				}
+				// Create wiki text
+				file_write(DATA_DIR, $page, $postdata);
+
+				// make diff data from backup
+				$backups = get_backup($page);
+				$_olddata = array_pop($backups);
+				$count = count($backups);
+				if( $count>0 ) {
+					$olddata = join('', $_olddata['data']);
+					$predata = join('', $backups[$count]['data']);
+
+					// Create and write diff
+					$diffdata = do_diff($predata, $olddata);
+					file_write(DIFF_DIR, $page, $diffdata);
+
+					// update backup
+					$strout = '';
+					foreach($backups as $data) {
+						$strout .= PKWK_SPLITTER . ' ' . $data['time'] . "\n"; // Splitter format
+						$strout .= join('', $data['data']);
+					}
+					$strout = preg_replace("/([^\n])\n*$/", "$1\n", $strout);
+
+					$fp = _backup_fopen($page, 'wb')
+						or die_message('cannot write file ' . htmlspecialchars($realfilename) .
+						'<br />maybe permission is not writable or filename is too long');
+					_backup_fputs($fp, $strout);
+					_backup_fputs($fp, $body);
+					_backup_fclose($fp);
+				}
+				else {
+					// no backup
+					unlink($filename);
+				}
+			}
+			header('Location: ' . get_script_uri() . '?' . rawurlencode($page));
+			exit;
+
+		} else {
+			$body .= "<p><strong>$_msg_invalidpass</strong></p>\n";
+		}
+	}
+
+	$s_page = htmlspecialchars($page);
+	$body .= <<<EOD
+<p>$_msg_diff_adminpass</p>
+<form action="$script" method="post">
+ <div>
+  <input type="hidden"   name="cmd"    value="diff" />
+  <input type="hidden"   name="page"   value="$s_page" />
+  <input type="hidden"   name="action" value="undo" />
+  <input type="password" name="pass"   size="12" />
+  <input type="submit"   name="ok"     value="$_btn_undo" />
+ </div>
+</form>
+EOD;
+
+	return array('msg'=>$_title_diff_undo, 'body'=>$body);
 }
 ?>