Taxonomy access user

At first sight, you may think it's just another fork of already available module on drupal.org like taxonomy_access or tac_lite. First one is a taxonomy control access based on roles, second one is a taxonomy control access based on users. But both of those modules miss the - according to me essential - inheritance notion :
if you have access to one term, you don't automatically have access to the children nodes. My module does take care about inheritance and this way permit a powerfull user access control.

Description:
For this description, I will try to illustrate the module with the following term scheme:
1 (root) -> 2 -> 4
-> 5 -> 7
-> 3 -> 6

The basic idea of inheritance is : if you have access to one term then you may access all children terms.

So I provided 4 different grant access for this module:
- grant_view
Which controls whether the user may view nodes associated to this term
- grant_update
Which controls whether the user may add nodes associated to this term or edit
them
- grant_delete
Which controls whether the user may delete nodes associated to this term
- grant_admin
Which is the most particular grant out of the four.

The last grant access (grant_admin) permits a user to "delegate" control of an access over a term to another user : if a lambda use has the grant_admin over the term 2, he may grant view to another user to terms 2, 4, 5 or 7.

So now you are familiar with the possible grant access, if the user lambda have grant_view on the term 1, then he may view nodes associated with the term 1, 2, 3, 4, 5, 6 and/or 7. The only record in the database about the grant access is about the term 1. To reach this goal in a reasonnable amount of time and with simple queries, I
used SQL functions in the DBMS.

Yet another feature of this module is the ability to restrain access to a subtree while he still have access to the other part. For example, if i set grant_view = 1 to the term 1 to the user lambda and grant_view = -1 to the term 2, then the user may view terms 1, 3 and 6 while access to terms 2, 4, 5 and 7 would be denied. The default value
is 0 and it's the value which permits inheritance.

This module also provides a UI to administer the module, views and views handler for specific fields. It is also tested with simpletest, some work on code coverage has been done.

This module could have multiple applications :
- An e-commerce website where a department supervisor may edit nodes associated to his department or delegate rights to his employees
- An news website where the person in charge of the sport section may only create articles in his own section or may delegate access to the golf area to one specific person.