Re: is there a possibility for gnus to download data without blocking?

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Wayne Harris <wharris1@protonmail.com> writes:

> Is there a possibility for gnus to download data without blocking?
> Wouldn't it be nice to be able to keep using EMACS while Gnus is
> downloading?
>
> Is it a limitation of EMACS itself?  If so, is there any plans for
> supporting such things in the future?  Wouldn't it be nice?

It would be lovely! There are a few issues: Emacs is single-threaded,
though it has the ability to continue execution while waiting on IO from
an external process. So theoretically we can already "download data
without blocking". In fact, Gnus already does this in a limited way:
when you hit "g", it starts an async external process for each of your
servers (each that involves an external process, anyway), then polls
each one until they're all done, and then continues with updating its
state.

That means there's really only a benefit when you have multiple servers
that can overlap their IO, and you're still going to wait as long as the
longest server takes.

In theory we could have a Gnus that fires off all the servers and then
returns control to the user immediately, but that would involve handling
out-of-band returns as they came in from the servers, and Gnus would
have to be structured very differently than it is now to manage that.

Eric