bug#58118: 29.0.50; Follow #target links in eww without re-rendering page

[Lars Ingebrigtsen <larsi@gnus.org>]

Visuwesh <visuweshm@gmail.com> writes:

> eww-follow-link currently follows #target links in the same URL by
> re-rendering the page.  Whilst this is fine for small HTML files, the
> 1.9M HTML file that I'm currently visiting takes a couple seconds to
> render.

That's a regression, I think -- following #target links used to work
without re-rendering.  (At least it did at one point.)

> I see that eww-display-html follows #target links by a text property
> search, why don't we do the same in eww-follow-link as well?  I have one
> question though: what do we about non-existent #targets?  Chrome and
> Firefox seem to not scroll when I add a non-existent #target to the
> current URL and say RET, and it seems to specially handle #top to mean
> to go to the top even if the HTML has no hits for "#top".  Should we
> handle the special #top target?

Sure, makes sense.

> +        (setq match (text-property-search-forward 'shr-target-id target #'member))
> +        (if match
> +            (goto-char (prop-match-beginning match))

This is more conveniently expressed as

(when-let ((text-property-search-forward 'shr-target-id target #'member))
  (goto-char (prop-match-beginning match)))