diff --git a/framework/yii/base/ErrorHandler.php b/framework/yii/base/ErrorHandler.php
index 99428fc..41fa7f9 100644
--- a/framework/yii/base/ErrorHandler.php
+++ b/framework/yii/base/ErrorHandler.php
@@ -114,17 +114,15 @@ class ErrorHandler extends Component
 					'exception' => $exception,
 				));
 			}
+		} elseif ($exception instanceof Arrayable) {
+			$response->data = $exception;
 		} else {
-			if ($exception instanceof Arrayable) {
-				$response->data = $exception;
-			} else {
-				$response->data = array(
-					'type' => get_class($exception),
-					'name' => 'Exception',
-					'message' => $exception->getMessage(),
-					'code' => $exception->getCode(),
-				);
-			}
+			$response->data = array(
+				'type' => get_class($exception),
+				'name' => 'Exception',
+				'message' => $exception->getMessage(),
+				'code' => $exception->getCode(),
+			);
 		}
 
 		if ($exception instanceof HttpException) {
diff --git a/framework/yii/gii/CodeFile.php b/framework/yii/gii/CodeFile.php
index 628adf9..bd77df6 100644
--- a/framework/yii/gii/CodeFile.php
+++ b/framework/yii/gii/CodeFile.php
@@ -11,6 +11,7 @@ use Yii;
 use yii\base\Object;
 use yii\gii\components\TextDiff;
 use yii\helpers\Html;
+use yii\helpers\StringHelper;
 
 /**
  * CodeFile represents a code file to be generated.
@@ -142,7 +143,8 @@ class CodeFile extends Object
 		if (in_array($type, array('jpg', 'gif', 'png', 'exe'))) {
 			return false;
 		} elseif ($this->operation === self::OP_OVERWRITE) {
-			return TextDiff::compare(file_get_contents($this->path), $this->content);
+			list ($diff, $addedLines, $deletedLines) = StringHelper::diff(file($this->path), $this->content);
+			return $diff;
 		} else {
 			return '';
 		}
diff --git a/framework/yii/gii/components/TextDiff.php b/framework/yii/gii/components/TextDiff.php
deleted file mode 100644
index d8f09ec..0000000
--- a/framework/yii/gii/components/TextDiff.php
+++ /dev/null
@@ -1,30 +0,0 @@
-<?php
-/**
- * @link http://www.yiiframework.com/
- * @copyright Copyright (c) 2008 Yii Software LLC
- * @license http://www.yiiframework.com/license/
- */
-
-namespace yii\gii\components;
-
-use Yii;
-
-/**
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @since 2.0
- */
-class TextDiff
-{
-	public static function compare($lines1, $lines2)
-	{
-		if (is_string($lines1)) {
-			$lines1 = explode("\n", $lines1);
-		}
-		if (is_string($lines2)) {
-			$lines2 = explode("\n", $lines2);
-		}
-		$diff = new \Horde_Text_Diff('auto', array($lines1, $lines2));
-		$renderer = new \Horde_Text_Diff_Renderer_Inline();
-		return $renderer->render($diff);
-	}
-}
diff --git a/framework/yii/helpers/StringHelperBase.php b/framework/yii/helpers/StringHelperBase.php
index e7d1d1e..c72fabc 100644
--- a/framework/yii/helpers/StringHelperBase.php
+++ b/framework/yii/helpers/StringHelperBase.php
@@ -7,6 +7,8 @@
 
 namespace yii\helpers;
 
+use yii\base\InvalidParamException;
+
 /**
  * StringHelperBase provides concrete implementation for [[StringHelper]].
  *
@@ -66,4 +68,49 @@ class StringHelperBase
 		}
 		return $path;
 	}
+
+	/**
+	 * Compares two strings or string arrays, and return their differences.
+	 * This is a wrapper of the Horde_Text_Diff package.
+	 * @param string|array $lines1 the first string or string array to be compared. If it is a string,
+	 * it will be converted into a string array by breaking at newlines.
+	 * @param string|array $lines2 the second string or string array to be compared. If it is a string,
+	 * it will be converted into a string array by breaking at newlines.
+	 * @param string $format the output format. It must be 'context', 'inline', or 'unified'.
+	 * @param string $engine the diff engine to be used. It must be 'auto', 'native', 'shell', 'string', or 'xdiff'.
+	 * @return array the comparison result. The first element is a string representing the detailed comparison result.
+	 * The second and the third elements represent the number of added lines and deleted lines, respectively.
+	 * @throws InvalidParamException if the format or the engine is invalid.
+	 */
+	public static function diff($lines1, $lines2, $format = 'inline', $engine = 'auto')
+	{
+		if (!is_array($lines1)) {
+			$lines1 = explode("\n", $lines1);
+		}
+		if (!is_array($lines2)) {
+			$lines2 = explode("\n", $lines2);
+		}
+		switch ($format) {
+			case 'context':
+				$renderer = new \Horde_Text_Diff_Renderer_Context();
+				break;
+			case 'inline':
+				$renderer = new \Horde_Text_Diff_Renderer_Inline();
+				break;
+			case 'unified':
+				$renderer = new \Horde_Text_Diff_Renderer_Unified();
+				break;
+			default:
+				throw new InvalidParamException("Output format must be 'context', 'inline' or 'unified'.");
+		}
+		if (!in_array($engine, array('auto', 'native', 'shell', 'string', 'xdiff'))) {
+			throw new InvalidParamException("Engine must be 'auto', 'native', 'shell', 'string' or 'xdiff'.");
+		}
+		$diff = new \Horde_Text_Diff($engine, array($lines1, $lines2));
+		return array(
+			$renderer->render($diff),
+			$diff->countAddedLines(),
+			$diff->countDeletedLines(),
+		);
+	}
 }