speed up relink script

[Matt Mackall]

On Fri, Mar 23, 2007 at 12:04:14PM -0700, Brendan Cully wrote:
> It's better if collect skips .d files, and you don't do any reading at
> all (eg the md5) until after the prune phase. I doubt the md5 is
> needed - directly comparing the indexes is probably enough. I don't
> think the head-comparing stuff is about speed - it's about possibly
> relinking even more files.

For comparing two (or more!) repos, you really don't want to seek back
and forth between them comparing single files at a time. Hence, storing
hashes of all the indices in one pass.

-- 
Mathematics is the supreme nostalgia of our time.