Re: [Libvir] A couple of questions about the Python bindings

On Tue, Mar 27, 2007 at 12:58:08PM +0100, Richard W.M. Jones wrote: > virDomainGetUUIDString, > virDomainPinVcpu, > virNetworkGetUUIDString: > > These functions don't seem to check whether the parameters are > correct. For example, virDomainGetUUIDString doesn't check if the > buffer parameter passed from Python is large enough to take the UUID string. > > virDomainPinVcpu is just plain strange (but I guess that strangeness > eminates from the Xen implementation), but it seems possible for the > Python code to be wrong about the length of the Vcpu map (string). > Shouldn't the length be taken from the string itself? I'm pretty sure all 3 of those methods will need to be hand-written rather than letting the generator do its thing. For the GetUUIDString() functions

the C prototype has the caller pass in a pre-allocate char * - which is getting translated in Python as the caller passing in a string object. This is dumb from the python POV where we have garbage collection. The Python wrapper code should allocate the correct sized char * when calling the GetUUIDString methods & then return a python string object. For the PingVCPU method things are more complicated - in C its a large bit field, although it is represented as a char *. In python I think we need to represent it as a list of VCPU numbers. > virDomainUndefine, > virNetworkUndefine: > > It's unclear from the libvirt documentation, but it sounds as if > these functions invalidate (free) the virDomainPtr / virNetworkPtr > object passed to them. (In fact, the Xen implementation of virDomainPtr > at least _doesn't_ free it - is that a bug?) If this is the case, then > the Python bindings ought to set self._o = None. Yes, the virDomainPtr objects ought to be free'd by these two functions, so the python should clear the _o member after the calls complete. It

should also clear it after virDomainDestroy if it doesn't already.