Fix caching of MIME config

* in get_mimes(): was missing isset() test
* in Email->_mimes_types(): static cache of reference was noneffective

refs 6ef498b

Author: vlakoff

system/core/Common.php

@@ -304,15 +304,22 @@ function config_item($item)
 	 */
 	function &get_mimes()
 	{
-		static $_mimes = array();
+		static $_mimes;
 
-		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))
+		if (empty($_mimes))
 		{
-			$_mimes = include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');
-		}
-		elseif (file_exists(APPPATH.'config/mimes.php'))
-		{
-			$_mimes = include(APPPATH.'config/mimes.php');
+			if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))
+			{
+				$_mimes = include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');
+			}
+			elseif (file_exists(APPPATH.'config/mimes.php'))
+			{
+				$_mimes = include(APPPATH.'config/mimes.php');
+			}
+			else
+			{
+				$_mimes = array();
+			}
 		}
 
 		return $_mimes;

system/libraries/Email.php

@@ -2234,15 +2234,18 @@ protected function _set_error_message($msg, $val = '')
 	 */
 	protected function _mime_types($ext = '')
 	{
-		static $mimes;
+		static $_mimes;
 
 		$ext = strtolower($ext);
 
-		if ( ! is_array($mimes))
+		if (empty($_mimes))
 		{
-			$mimes =& get_mimes();
+			// references cannot be directly assigned to static variables, so we use an array
+			$_mimes[0] =& get_mimes();
 		}
 
+		$mimes =& $_mimes[0];
+
 		if (isset($mimes[$ext]))
 		{
 			return is_array($mimes[$ext])