Yii-1.x hhvm error handler hack

Hhvm.php

<?php

/**
 * How to prevent "white page" on CHttpException and other errors
 * 
 * Instruction:
 * 1. place Hhvm.php to protected.components
 * 2. add to index.php lines:
 * 
 * define('YII_DEBUG', false);
 * define('YII_ENABLE_EXCEPTION_HANDLER', false); // disable yii exception handler
 * define('YII_ENABLE_ERROR_HANDLER', false); // disable yii error handler
 * 
 * 
 * //////
 * ///// <------ config and other code here 
 * /////
 * 
 * // init YII
 * $app = Yii::createWebApplication($config);
 * 
 * // add hhvm handlers
 * Hhvm::initSystemHandlers();
 * $app->run();
 * 
 * 3. proffit
 * 
 * 
 * @see Hhvm::initSystemHandlers
 * @author hcbogdan
 */
class Hhvm
{


    public static function handleException($exception)
	{
        // disable error capturing to avoid recursive errors
        restore_error_handler();
        restore_exception_handler();

        $category='exception.'.get_class($exception);
        if($exception instanceof CHttpException)
            $category.='.'.$exception->statusCode;
        // php <5.2 doesn't support string conversion auto-magically
        $message=$exception->__toString();
        if(isset($_SERVER['REQUEST_URI']))
            $message.="\nREQUEST_URI=".$_SERVER['REQUEST_URI'];
        if(isset($_SERVER['HTTP_REFERER']))
            $message.="\nHTTP_REFERER=".$_SERVER['HTTP_REFERER'];
        $message.="\n---";
        Yii::log($message,CLogger::LEVEL_ERROR,$category);

        $event=new CExceptionEvent(app(),$exception);
        app()->onException($event);
        if(!$event->handled)
        {
            // try an error handler
            if(($handler=app()->getErrorHandler())!==null)
                $handler->handle($event);
            else
                app()->displayException($exception);
        }
	}



    public static function handleError($code,$message,$file,$line)
	{
		if($code & error_reporting())
		{
			// disable error capturing to avoid recursive errors
			restore_error_handler();
			restore_exception_handler();


			$log="$message ($file:$line)\nStack trace:\n";
			$trace=debug_backtrace();
			// skip the first 3 stacks as they do not tell the error position
			if(count($trace)>3)
				$trace=array_slice($trace,3);
			foreach($trace as $i=>$t)
			{
				if(!isset($t['file']))
					$t['file']='unknown';
				if(!isset($t['line']))
					$t['line']=0;
				if(!isset($t['function']))
					$t['function']='unknown';
				$log.="#$i {$t['file']}({$t['line']}): ";
				if(isset($t['object']) && is_object($t['object']))
					$log.=get_class($t['object']).'->';
				$log.="{$t['function']}()\n";
			}
			if(isset($_SERVER['REQUEST_URI']))
				$log.='REQUEST_URI='.$_SERVER['REQUEST_URI'];
			Yii::log($log,CLogger::LEVEL_ERROR,'php');


			Yii::import('CErrorEvent',true);
			$event=new CErrorEvent(app(),$code,$message,$file,$line);
			app()->onError($event);
			if(!$event->handled)
			{
				// try an error handler
				if(($handler=app()->getErrorHandler())!==null)
					$handler->handle($event);
				else
					app()->displayError($code,$message,$file,$line);
			}
		}
	}



    /**
	 * Initializes the error handlers.
	 */
	public static function initSystemHandlers()
	{
        set_exception_handler('Hhvm::handleException');
        if(YII_DEBUG)
            set_error_handler('Hhvm::handleError', error_reporting());
	}

}