Format once

[arrdem]

This patch fixes #55, by inlining the valid-format? check and tweaking diff generation so that files are never read or formatted twice. This gives the expected 50% speedup.

before:

lein cljfmt fix src/clj 772.30s user 1.78s system 101% cpu 12:41.43 total

after:

lein cljfmt fix src/clj 396.35s user 1.40s system 103% cpu 6:23.34 total

merges cleanly with #54

[weavejester]

Thanks for the patch! Looking at your commits, it seems like 79307f2 has no purpose without 12052b7, so I think those two should be squashed together.

So perhaps we start with 4df8fc6, but let's change the commit message to simply:

Don't reformat files twice in fix

The "how" is obvious from the diff, I think, so there's no need to explain it in the commit message.

Then we combine 79307f2 and 12052b7 into one, perhaps with the message:

Don't reformat files twice in check

Again, I think the diff explains the "how".

You also should remove the valid-format? function, since it's no longer necessary after 12052b7.

[arrdem]

Done and done.