callout on property change

[Joe Shaw]

On Tue, 2004-04-20 at 12:56 -0400, Robert Love wrote:
> Hello, guys.
> 
> I added callout-on-property-change, because we need it to do lots of
> things, such as a replacement for ifplugd (take action on link change).
> See attached patch.

Looks good to me.

> Couple of design decisions:

These all seem fine to me.  I don't think property add/remove is too
interesting either.  Presumably if someone needs to act on it, they
could do it when the device or a capability is added.
        
>         - However, VALUE is currently hardcoded to foo until I write
>         hal_property_to_string().

This should be fixed before checking it in, though. ;)  There's already
hal_property_get_as_string() (although _to_string() is a better name,
for sure).  So you can just use that if you're dealing with
HalPropertys.  Otherwise, you can just write
hal_device_property_to_string() (or whatever) which just gets the
HalProperty and calls hal_property_to_string() on it.  The other
hal_device_property functions do that, so you can just use one of those
as a template.

> I know there were some concerns about properties changing too often for
> a callout to remain sane.  In my testing, however, there were
> surprisingly few property-modified callouts occurring - perhaps since I
> only report when a property changes (as opposed to add/remove)?  During
> my testing, the only property change callouts I saw were me pulling out
> my ethernet cable to test.  So who knows.

I think they were mostly my natural worry reflex kicking in.  I'm glad
to see it's not really an issue either way.

Joe


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