[libvirt] About node device enumeration problem

Hi all, I saw two sets of node device enumeration implementation in libvirt-0.7.4 source code: 1.libudev implementation 2.HAL-based implementation I want to know which kind is used in libvirt.if both are used, which kinds solution is better? in my opinion,their abstract layer is different,HAL-based implementation may be flexible, by contrast, libudev implementation may be with better performance.whether plan to merge them or reserve a kind of implementation? thank you very much.I would be most grateful for any response . Best Regards, Alex Jia