Best way to check whether working tree matches a commit's tree

Hi,

I'd like to check whether my working tree exactly matches the tree of a given commit. That is, there should not be any untracked, staged or modified files (including ignored files).

Currently, I'm doing this in two steps:

- check for success and empty output of "git status --ignored --porcelain"
- check that the output of "git rev-parse HEAD" matches the given commit

While this works, it feels sub-optimal. Is there a better / smarter way?

-- 
Sebastian Schuberth