GNU bug report logs -
#38011
27.0.50; [PATCH] WIP on allowing Gnus backends to return header data directly
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Message #8 received at submit <at> debbugs.gnu.org (full text, mbox):
Eric Abrahamsen <eric <at> ericabrahamsen.net> writes:
> This patch provides the possibility for backends to return their own
> headers (ie a list of vectors), though it doesn't actually change any of
> the backends to do that -- that will be another patch.
Great!
> I have one question at this stage: the 'nov or 'headers value gets
> stored into the `gnus-headers-retrieved-by' variable. That variable is
> later checked in a couple of places like so:
>
> (when (and gnus-fetch-old-headers
> (eq gnus-headers-retrieved-by 'nov))
> (if (eq gnus-fetch-old-headers 'invisible)
> (gnus-build-all-threads)
> (gnus-build-old-threads)))
>
> If the variable is 'headers, the `gnus-build-*-threads' functions don't
> get called at all.
>
> What's the difference between 'nov and 'headers, and why can we build
> threads in one case and not the other? If backends were to return their
> own headers, what value should they return?
It's not about threading per se, but about displaying information about
already-read articles (or more precisely -- about articles not in the
set that was requested). Threads are build no matter how the backend
delivers the data.
If nn-*retrieve-headers supports NOV fetching, then certain Gnus
variables about filling in threads with "old" articles is switched on,
because fetching extra NOV headers is fast (you just say "fetch 100-150"
instead of "fetch 100-110,120-130,150"). With the backends that fetch
head by head, this is slow, so it's not done.
It's basically a distinction between NNTP and almost all the other
backends.
--
(domestic pets only, the antidote for overdose, milk.)
bloggy blog: http://lars.ingebrigtsen.no
This bug report was last modified 4 years and 143 days ago.
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