Improved comments in memcached cache driver.

system/cache/driver/file.php

 <?php namespace System\Cache\Driver;
 
-class File implements \System\Cache\Driver {
+class Memcached implements \System\Cache\Driver {
 
 	/**
 	 * All of the loaded cache items.
@@ -34,25 +34,14 @@ class File implements \System\Cache\Driver {
 			return $this->items[$key];
 		}
 
-		if ( ! file_exists(APP_PATH.'cache/'.$key))
-		{
-			return $default;
-		}
+		$cache = \System\Memcached::instance()->get(\System\Config::get('cache.key').$key);
 
-		$cache = file_get_contents(APP_PATH.'cache/'.$key);
-
-		// --------------------------------------------------
-		// Has the cache expired? The UNIX expiration time
-		// is stored at the beginning of the file.
-		// --------------------------------------------------
-		if (time() >= substr($cache, 0, 10))
+		if ($cache === false)
 		{
-			$this->forget($key);
-
 			return $default;
 		}
 
-		return $this->items[$key] = unserialize(substr($cache, 10));
+		return $this->items[$key] = $cache;
 	}
 
 	/**
@@ -65,7 +54,7 @@ class File implements \System\Cache\Driver {
 	 */
 	public function put($key, $value, $minutes)
 	{
-		file_put_contents(APP_PATH.'cache/'.$key, (time() + ($minutes * 60)).serialize($value), LOCK_EX);
+		\System\Memcached::instance()->set(\System\Config::get('cache.key').$key, $value, 0, $minutes * 60);
 	}
 
 	/**
@@ -76,7 +65,7 @@ class File implements \System\Cache\Driver {
 	 */
 	public function forget($key)
 	{
-		@unlink(APP_PATH.'cache/'.$key);
+		\System\Memcached::instance()->delete(\System\Config::get('cache.key').$key);
 	}
 
 }
\ No newline at end of file