[libvirt] new API to get list of *all* interfaces matching a MAC

[Daniel P. Berrange]

On Tue, Aug 25, 2009 at 04:04:44PM +0200, Daniel Veillard wrote:
> On Tue, Aug 25, 2009 at 10:15:05AM +0100, Daniel P. Berrange wrote:
> > On Mon, Aug 24, 2009 at 03:24:13PM -0400, Laine Stump wrote:
> > > (This probably seems like overanalysis of a simple problem. That's what 
> > > I'm best at ;-)
> > > 
> > > Due to oversight, the function virInterfaceLookupByMACString() can only 
> > > return a single interface, but it's possible that a host may have more 
> > > than one interface with the same MAC. Since the API had already been 
> > > released by the time we realized this, the existing function will remain 
> > > and a new one added that can return a list of interfaces. This new API 
> > > will need to deal with the fact that the list length is effectively 
> > > unbounded. I can see three ways of dealing with this, and want to learn 
> > > which is preferred by others before spending time on the implementation.
> > 
> > I'm rather wondering why exactly we need another API. 
> 
>  Basically to be able to obsolete the broken one, and explain in the
> documentation the function limitation and suggest using the new one.
> Way simpler to explain than suggesting doing the full extract and leave
> the user filter.

I don't buy that argument. We have a clear split between vir*Lookup*
methods returning a single object, and vir*List* methods giving back
multiple objects, which is consistent across all the APIs. I don't
think we need to do a specialcase for network interfaces, for something
that'll rarely be an issue in the real world. The existing behaviour
is easy to understand & document & deal with from applicaton code as 
it is.

Daniel
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