match: add visitchildrenset complement to visitdir...
match: add visitchildrenset complement to visitdir
`visitdir(d)` lets a caller query whether the directory is part of the matcher.
It can receive a response of 'all' (yes, and all children, you can stop calling
visitdir now), False (no, and no children either), or True (yes, either
something in this directory or a child is part of the matcher).
`visitchildrenset(d)` augments that by instead of returning True, it returns a
list of items to actually investigate. With this, code can be modified from:
for f in self.all_items:
if match.visitdir(self.dir + '/' + f):
<do stuff>
to be:
for f in self.all_items.intersect(match.visitchildrenset(self.dir)):
<do stuff>
use of this function can provide significant performance improvements,
especially when using narrow (so that the matcher is much smaller than the stuff
we see on disk) and/or treemanifests (so that we can avoid loading manifests for
trees that aren't part of the matcher).
Differential Revision:
https://phab.mercurial-scm.org/D4130
