PropertiesChanged signal, take 2

David Zeuthen zeuthen at
Thu May 13 07:46:24 PDT 2010


On Thu, May 13, 2010 at 9:42 AM, Thiago Macieira <thiago at> wrote:
>> Anyway, the "reduction in bandwidth" thing was really just an aside.
>> The main thing I wanted to say was just that true_no_value really
>> doesn't help at all because PropertiesChanged() don't convey such
>> properties at all.
> Why not? I don't get your statement here. To me it sounds like we can support
> Lennart's request without any trouble.

My point was simply that the name of the property that changed wasn't
conveyed to the client. For example, if you don't want to push the
SMART property in PropertiesChanged() you still want to convey to
clients that the only the SMART property has changed... because
otherwise the client would need to reget all properties which might
turn out to be very expensive ... and undermine the whole idea of
caching properties in the first place!

I just sent a patch to make it possible to do this. This way
client-side proxies can reliably cache properties including letting
users know

  "I don't have a cached value of the Smart data - the server just told me
   that the property was invalidated and I haven't gotten the new value
   yet.. sorry!"

I hope this clarifies....


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