Read only publishing option

Hello,

I have coded the 'Read only node' module and in the project review (https://www.drupal.org/node/2344695) somebody told me that this is a feature that could be in your module.

I have tested your module and I can imagine the possibility to add a new permission for each custom publishing option that allow (or not) to access the node with this particular publishing option.

For exemple, if you add a new publishing option named 'Lock' you could have 2 permission :
the 'Can access/use lock custom publishing option on node forms ' and
'Can access the node with lock custom publishing option'.

what do you think ?