setup.py: use bytes literals
The b() helper was needed because Python < 2.6 didn't support bytes
literals (b''). Now that we don't support Python < 2.6, we no longer
need this helper.
merge: rework manifestmerge to use a matcher
This opens the door to working slightly more closely with the manifest
type and letting it optimize out some of the diff comparisons for us,
and also makes life significantly easier for narrowhg.
merge: restate calculateupdates in terms of a matcher
Once we get a matcher down into manifestmerge, we can make narrowhg
work more easily and potentially let manifest.match().diff() do less
work in manifestmerge.
merge: have merge.update use a matcher instead of partial fn
This is relatively rarely used functionality, but migrating this to a
matcher will make future work on narrow clones more feasible.
treemanifest: don't iterate entire matching submanifests on match()
Before
2773540c3650 (match: remove unnecessary optimization where
visitdir() returns 'all', 2015-05-06), match.visitdir() used to return
the special value 'all' to indicate that it was known that all
subdirectories would also be included in the match. The purpose for
that value was to avoid calling the matcher on all the paths. It
turned out that calling the matcher was not a problem, so the special
return value was removed and the code was simplified. However, if we
use the same special value for not just avoiding calling the matcher
on each file, but to avoid iterating over each file, it's a much
bigger win. On commands like
hg st --rev .^ --rev . dom/
we run the matcher (dom/) on the two manifests, then diff the narrowed
manifest. If the size of the match is much larger than the size of the
diff, this is wasteful. In the above case, we would end up iterating
over the 15k-or-so files in dom/ for each of the manifests, only to
later discover that they are mostly the same. This means that runningt
the command above is usually slower than getting the status for the
entire repo, because that code avoids calling treemanifest.match() and
only calls treemanifest.diff(), which loads only what's needed for the
diff.
Let's fix this by reintroducing the 'all' value in match.visitdir()
and making treemanifest.match() return a lazy copy of the manifest
from dom/ and down (in the above case). This speeds up the above
command on the Firefox repo from 0.357s to 0.137s (best of 5). The
wider the match, the bigger the speedup.