bug#32729: Xemacs 23 times as fast as GNU Emacs

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Sun, 13 Oct 2019 19:24:58 +0200
> Cc: Kevin Layer <layer@franz.com>, "Benninghofen,
>  Benjamin Dr." <benjamin.benninghofen@airbus.com>, 32729@debbugs.gnu.org,
>  32728@debbugs.gnu.org
> 
> It is unfortunate that stuff like this makes Emacs hang, though.  It'd
> be nice if Emacs had a "OK, we just give up" mode if the buffer is too
> intractable, where "too intractable" may be, for instance, if it finds a
> line that's longer than a few megabytes, perhaps?
> 
> I don't know what "just give up" would entail, though.  Just put point
> at the start of the buffer and refuse to scroll or do anything?  Just
> about anything would be better than the current situation where you have
> to kill Emacs if you're playing with (some) binary files and try to
> display the buffer.

The problem is exactly to decide what to do when you "give up" in a
way that will still get you a functional editor that can display
something reasonable.