[MERGE] 4% improvement to commit's common case

[Robert Collins]

The common case for commit is most files unchanged, the same number of
paths. The PointlessCommit check currently takes > 4% of the time for an
incremental commit. This code changes the commit builder interface to
return information about whether a change has been recorded for a given
file, and saves 4% on current bzr.dev incremental commits.

This has one flaw at the moment - it uses inventory._byid for delete
detection, which may not work all that well in the future. For now
though its a significant improvement, and IMO worth doing - we can
refactor to not use _byid by a couple of different routes, but that
doesn't need to block this patch - because its not clear to me that
_byid shouldn't be used within bzrlib :).

-Rob
-- 
GPG key available at: <http://www.robertcollins.net/keys.txt>.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bzr-mail-KoCMIO.patch
Type: text/x-patch
Size: 16332 bytes
Desc: not available
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20070920/59d16da6/attachment.bin 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : https://lists.ubuntu.com/archives/bazaar/attachments/20070920/59d16da6/attachment.pgp