Hello,
My name is Michał Szulczyński, and I'm a student at Warszawska Wyższa Szkoła Informatyki in Poland. I'm on a practice at the company where Aleksander Adamowski works. As he said, I will try to implement dynamic list member 'caching'. The general idea is to "materialize" the member attribute of the dynamic group using existing static attribute values infrastructure (including indexes) and update them automatically when there is a add/modify/modrdn/delete operation on an object that matches the dynlist memberURL filter.
The operation of dynlist overlay would be identical as it is now without specifying an additional dynlist configuration option.
The plan is to, depending on the additional, optional dynlist-attrset configuration parameter, grab the dynamic list entries for that dynlist configuration from the database, and put them into a memory-resident list (which would hold all the dynamic groups that we are interested in, ie. the ones with the additional configuration option set). When there is a add/mod/modrdn/delete operation on any entry, we would check this list for a matching dynlist filter, and add/modify/delete the member attribute of the dynamic list for that entry. Much like a static group, but with automated addition/deletion to/from it, effectively making it a dynamic group. Manual updates to the member attribute would be prevented and would raise an error.
First, in addition to dynlist_info_t we would need to hold the pointer to our memory-resident dynamic group list per dynlist overlay instance. That's for speed optimization, since searching for all dynamic lists on each update operation would have a huge performance impact. As we can only hold only one backend-specific config data in Operation->o_bd->bd_info->on_bi.bi_private, we wold need to hold both pointers (dynlist_info_t and the pointer to our list) in an additional struct, and store that. But this method would mean changing much of the existing codebase, and I don't know if that would be good. If there would be another place where we could store the pointer to the dynamic group list, that would be better.
Second, I would like to know if there is a function to test whether one DN is contained in another DN (i.e. one DN is a descendant to another DN). I need this to compare the base DN of the dynamic group, and the added/modified/deleted/modrdn'ed entry (eg: if the entry DN <uid=test,l=City,ou=People,o=MyOrg> is in the dynamic group's member URL's base DN <ou=People,o=MyOrg>). I think that comparing the normalized DN's stringwise backwards from the strings' end would work, but I'm not sure.
Third: * can we do an add-or-replace with BackendDB->be_modify * when doing a LDAP_MOD_DELETE on a single attribute's value can we ignore a case where that attribute value does not exist in the entry (so we can avoid checking for its presence and save an unnecessary read operation)?
-- Michał Szulczyński Praktykant Altkom Akademia S.A. http://www.altkom.pl Warszawa, ul. Chłodna 51
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