Package =TWiki::Access 
A singleton object of this class manages the access control database.
Construct a new singleton object to manage the permissions
database.
 ObjectMethod permissionsSet ($web) -> $boolean 
Are there any security restrictions for this Web
(ignoring settings on individual pages).
Return a string describing the reason why the last access control failure
occurred.
 ObjectMethod *checkAccessPermission ($action,$user,$text,$meta,$topic,$web) -> $boolean 
Check if user is allowed to access topic 
-  $action- 'VIEW', 'CHANGE', 'CREATE', etc.
-  $user- User object
-  $text- If undef or '': Read '$theWebName.$theTopicName' to check permissions
-  $meta- If undef, but$textis defined, then metadata will be parsed from$text. If defined, then metadata embedded in$textwill be ignored. Always ignored if$textis undefined. Settings in$metaoverride * Set settings in plain text.
-  $topic- Topic name to check, e.g. 'SomeTopic' *undef to check web perms only)
-  $web- Web, e.g. 'Know'
 
If the check fails, the reason can be recoveered using getReason.