Is there a library for monitoring a git repository for any changes?

Hi git,

I want to work on a visualization program for git. I was hoping there was a library that would allow me to monitor a git repo for changes. Consider it like inotify, but for a git repository (in fact, I think it would probably have inotify under the hood).

This hypothetical library would trigger an event any time the repository was modified, i.e. any time the graph that represents history was changed.

Is there such a library? If not, is there a better way to monitor the repository so that I wouldn't need to write it myself? Would anyone else be interested if I wrote it myself?

Cheers,

Robert