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.
$ hg init repo
$ cd repo
$ i=0; while [ "$i" -lt 213 ]; do echo a >> a; i=`expr $i + 1`; done
$ hg add a
$ cp a b
$ hg add b
Wide diffstat:
$ hg diff --stat
a | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
b | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 426 insertions(+), 0 deletions(-)
diffstat width:
$ COLUMNS=24 hg diff --config ui.interactive=true --stat
a | 213 ++++++++++++++
b | 213 ++++++++++++++
2 files changed, 426 insertions(+), 0 deletions(-)
$ hg ci -m adda
$ cat >> a <<EOF
> a
> a
> a
> EOF
Narrow diffstat:
$ hg diff --stat
a | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
$ hg ci -m appenda
>>> open("c", "wb").write("\0")
$ touch d
$ hg add c d
Binary diffstat:
$ hg diff --stat
c | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
Binary git diffstat:
$ hg diff --stat --git
c | Bin
d | 0
2 files changed, 0 insertions(+), 0 deletions(-)
$ hg ci -m createb
>>> open("file with spaces", "wb").write("\0")
$ hg add "file with spaces"
Filename with spaces diffstat:
$ hg diff --stat
file with spaces | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
Filename with spaces git diffstat:
$ hg diff --stat --git
file with spaces | Bin
1 files changed, 0 insertions(+), 0 deletions(-)
diffstat within directories:
$ hg rm -f 'file with spaces'
$ mkdir dir1 dir2
$ echo new1 > dir1/new
$ echo new2 > dir2/new
$ hg add dir1/new dir2/new
$ hg diff --stat
dir1/new | 1 +
dir2/new | 1 +
2 files changed, 2 insertions(+), 0 deletions(-)
$ hg diff --stat --root dir1
new | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
$ hg diff --stat --root dir1 dir2
warning: dir2 not inside relative root dir1
$ hg diff --stat --root dir1 -I dir1/old
$ cd dir1
$ hg diff --stat .
dir1/new | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
$ hg diff --stat --root .
new | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
$ hg diff --stat --root ../dir1 ../dir2
warning: ../dir2 not inside relative root . (glob)
$ hg diff --stat --root . -I old
$ cd ..