Re: Support for explicitly resetting the idle timer?

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 27 Nov 2021 18:54:56 +1100
> From: Campbell Barton <ideasman42@gmail.com>
> 
> There is a package I use/maintain which implements something like 
> Firefox's auto-scroll (click-drag to scroll up/down) [0].
> 
> An issue with this is (unlike mouse wheel scrolling) using track-mouse 
> doesn't handle keyboard events in a way that resets the idle timer.
> 
> So while scrolling, idle timers may run (which can cause visible 
> stuttering).
> 
> I've worked around this by locally let binding `timer-idle-list` to nil, 
> however this back-fires if any timers are added while scrolling (rare 
> but possible), workarounds for this are possible - but they involve 
> clearing the list while scrolling then moving the contents into the real 
> `timer-idle-list` list... which as far as I can see is quite error 
> prone, especially if packages are inspecting the contents of this list.
> 
> All this complexity could be avoided if the function `timer_stop_idle` 
> in ./src/keyboard.c was exposed to elisp, this way scripts that use 
> mouse input could explicitly reset the idle timer on mouse based 
> user-interaction (when it makes sense).

The cleanest solution in this case would be to call timer_stop_idle if
Emacs is executing a command, no matter how it was invoked.  In fact,
I'm surprised that we don't stop idle timers when track-mouse invokes
commands: it sounds like a bug we should fix.