roundcubemail/program/lib/Roundcube/rcube_plugin_api.php
public function is_processing($hook = null)
    {
        return count($this->exec_stack) > 0 && (!$hook || in_array($hook, $this->exec_stack));
    }
public function is_processing($hook = null)
    {
        return count($this->exec_stack) > 0 && (!$hook || in_array($hook, $this->exec_stack));
    }
public function is_processing ( $ hook = null ) { return count ( $ this -> exec_stack ) > 0 && ( ! $ hook || in_array ( $ hook , $ this -> exec_stack ) ) ; }
Check if a plugin hook is currently processing.
Mainly used to prevent loops and recursion.

@param string $hook Hook to check (optional)

@return boolean True if any/the given hook is currently processed, otherwise false
Check if a plugin hook is currently processing . Mainly used to prevent loops and recursion .