TWiki::Access
$action
- 'VIEW', 'CHANGE', 'CREATE', etc.
$user
- User object
$text
- If undef or '': Read '$theWebName.$theTopicName' to check permissions
$topic
- Topic name to check, e.g. 'SomeTopic' *undef to check web perms only)
$web
- Web, e.g. 'Know'