Re: MIME parts not saved

[Katsumi Yamaoka <yamaoka@jpl.org>]

Dan Christensen wrote:
> Katsumi Yamaoka <yamaoka@jpl.org> writes:
>> Now a temporary file will be deleted by a timer 10 seconds after
>> launching xdg-open.

> There's already logic to delay deletion in mm-display-external, although
> for some reason it is only used in certain situations.  Maybe your
> change can be merged with the existing code?

Why I didn't use `mm-postponed-undisplay-list' was that a data
file is made read-only (i.e., not editable) and a viewer doesn't
need the file all the while it is running.  However, given even
a 30 seconds delay is not enough, I think we should not stick to
the speediness of deleting the file.

> I find that even a 30 second delay is not enough sometimes, as
> certain viewers notice the deletion and stop displaying the file.

I can imagin it; even in a fast machine, ooffice or equivalent
takes a long time for starting up.  Moreover, Gnus will never
know what program xdg-open and the like launches nor when the
program finishes.  So, we may have to keep all temporary files
from being deleted.

> So I think it would be convenient to have a variable which indicates
> that temporary files should be left forever, to be cleaned up as
> other files in /tmp are.

Hm, if it is boolean and defaults to nil (deleting), I don't
think a user will find it and alter the value.  Instead, how
about deleting temporary files at the next time Gnus starts?
That is:

o Save a list of files to be deleted in "$TMP/.mm-temp-files" when
  Gnus exits.
o Try to delete those files when Gnus starts.  If it fails on
  deleting of some files, schedule them to delete again.

This way will be helpful also for Emacs on Windows and Cygwin.