Re: Canceling pending getUserMedia() call

On Mon, Apr 27, 2015 at 6:53 AM, Harald Alvestrand <harald@alvestrand.no>
wrote:

> Den 27. april 2015 14:15, skrev Jan-Ivar Bruaroey:
> > What happened to "a more general discussion [...] about permissions and
> > what APIs we should offer around them"? - We seem to have moved on to
> > where to stick the API (which is irresistible, so I'll jump in).
>
> There is a whole shiny new document out:
>
> https://w3c.github.io/permissions/
>
> This neatly sidesteps the whole question of how to request a permission
> you don't have, but does offer a way to query whether a prompt will be
> displayed if you try to ask for the permission.
>
> It also fails to cover the case of access to non-global objects.
>
> Still, it's an indication that this discussion is happening elsewhere.
>
> > Can we sidestep the whole fetch debate with:
> > navigator.mediaDevices.cancelOutstandingGumRequests() ?
> >
> > Making promises cancellable is a terrible idea, because a promise can be
> > passed around to several functions without granting control to any of
> > them. Nevermind that any function acting on said control would affect
> > all the other ones (action-at-a-distance). Control has to live upstream
> > in the tree, and it's not for the recipient of a promise to break,
> > resolve or reject it.
> >
> > The only other approach I though had legs was the cancellableToken
> > (because inputs and outputs: Promise is an output, control should be an
> > input. As tempting as it is to overload the returned object, it'll muck
> > up the first wrapper that comes along), especially the promise-version
> > Martin suggested, but hopefully we wont need such fine control here.
>
> So I have two questions, one administrative and one technical:
>
> 1) Do we need this to have a viable 1.0 specification?
>

Well, I think it depends if you expect promises to eventually be
cancellable.
If you do, then we can just publish 1.0 and wait.



> 2) If "yes", does cancelOutstandingRequests seem like a good idea?
>

No.

-Ekr