Re: Image cache

[Stefan Monnier <monnier@iro.umontreal.ca>]

> One certainly doesn't want to do a stat on _every_ reference, as stats
> can be expensive (and the thumbs package will tend to use lots of
> images); I think there would have to be some sort of counter/timer,
> e.g., only stat if more than 30 seconds since the last stat.  However
> as the stat info would give you time information anyway, that should
> be relatively straightforward.

The timeout is fairly arbitrary, so it's invariably turn out to be
unnecessarily short for half the cases and too long for the other half.

I much prefer an explicit way to force a check, which can be used in
create-image.  And in those rare cases where the image may change without
Emacs being directly involved, then a run-with-idle-timer can implement
the timeout.


        Stefan