Moved fields corresponding to role entries to the ACL_ROLE class.

from the grant role to role graph.

resets the initial role access bits.

Also called show grants before and after set role. Unfortunately the role
privileges printing are not implemented yet.

The testcase checks to see if the privileges are set accordingly to a newly
created user. This is the most general usecase.

The testcase checks to see if the create user command sets the is_role column
to 'N' by default

SET ROLE NONE;

separate function.

as well as only set privileges in the update() function.

the current user via the current security_context

roles

Renaming a user via RENAME USER command causes either the user columns
to update, or the role columns.

The function now handles user updates/deletions correctly.

Also fixed a bug regarding the HASH iteration. It previously got
the stop condition from a different hashtable and this caused errors
when the hash sizes were different.

consistent.

The logic is not complete yet.

no longer valid entries in the roles_mappings HASH. This job will be delegated
to handle_grant_* functions

It will only hold _valid_ entries for as long as it held in memory. Any change
regarding acl_users or acl_roles in memory should update the structure
immediately. This is why the rebuild_roles_mappings no longer removes invalid
entries.

In order to keep things consistent with the existing code, the following jobs
are assigned to each function:

The role of rebuild_roles_mappings is to recreate the links between users and
roles. Any other updates are to be done in the functions:

handle_grant_*

This change prepares the code for the next step, which is cascading updates.

function