RE: Overlays configuration (Was: commit: ldap/ configure)

["Pierangelo Masarati" <ando@sys-net.it>]

>> -----Original Message-----
>> From: owner-openldap-devel@OpenLDAP.org
>> [mailto:owner-openldap-devel@OpenLDAP.org]On Behalf Of Pierangelo
>> Masarati
>
>> I've thought a bit more on this; for each backend, I'd allow:
>>
>> user_no|no|auto|yes|mod|user_yes|user_mod
>>
>> but only advertize
>>
>> no|auto|yes|mod
>>
>> and only use no|yes as defaults
>>
>> with either no|auto|yes used as default.
>> When the user picks any of no|yes|mod,
>> the user_* from should be assigned to the
>> configure var.
>>
>> - auto|yes|mod means specific backend build
>>   is allowed not to take place if requirements
>>   are not met without global build failure;
>> - no|user_no means specific backend build
>>   must not even be attempted
>> - user_yes|user_mod means global build must
>>   fail if specific backend requirements are
>>   not met.
>>
>> --enable-backends should take the values
>> no|yes|mod, where:
>> - no means promote all yes to no
>> - yes means promote all no to yes
>> - mod means promote all yes|no to mod
>>
>> As a consequence, --enable-backends replaces
>> backends' defaults with other legal default
>> values, does not affect specific explicit
>> backend enables and causes enabled backends to
>> compile only if requirements are met.
>>
>> If there's no objection, I'd start coding this.
>
> Hm, I need to think some more about this.
>
> There are only two default states: no and yes, but not mod.
> There are three user states: no, yes, and mod.
> I think there are also two auto states: auto,yes and auto,mod. Currently
> none of our backends default to an auto.
>
> To me, using enable-backends=no means "turn all backends off" which of
> course is senseless because then slapd cannot be built. You're treating
> it as "turn all default-yes backends to user-no" which I guess is more
> useful, but less intuitive.

Mmmmh, I guess I stated it badly; I'm treating enable-backends=no
to turning all backends to "no"; this should only be used in
conjunction with enable-<somebackend>=yes.  If more than one defaults
to yes, or if we add "auto" (which I encourage), then someone could
desire: disable all those that default to "yes" or "auto", except those
that are explicitly enabled.

>
> Then, enable-backends=yes in light of this discussion would mean set all
> default-no backends to auto,yes, and enable-backends=mod would mean turn
> all default-yes and default-no backends to mod.
>
> Does that follow?

More or less, yes.  This would be exactly the opposite of "=no", i.e.
enable all those that would default to no.  The important distinction, is
that those enabled by enable-backends should be build only if possible. 
I.e., if I don't have libiodbc installed, and I enable all backends, I
don't want the build to fail because back-sql cannot be built.  I simply
want it to be skipped (maybe with a warning) but all else be built.

p.

-- 
Pierangelo Masarati
mailto:pierangelo.masarati@sys-net.it