status: prefer relative paths in Rust code
… when the repository root is under the current directory,
so the kernel needs to traverse fewer directory in every call
to `read_dir` or `symlink_metadata`.
Better yet would be to use libc functions like `openat` and `fstatat`
to remove such repeated traversals entirely, but the standard library
does not provide APIs based on those.
Maybe with a crate like https://crates.io/crates/openat instead?
Benchmarks of `rhg status` show that this patch is neutral in some configurations,
and makes the command up to ~20% faster in others.
Below is semi-arbitrary subset of results. The four numeric columns are:
time (in seconds) with this changeset’s parent, time with this changeset,
time difference (negative is better), time ratio (less than 1 is better).
```
mercurial-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.0061 -> 0.0059: -0.0002 (0.97)
mercurial-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0029 -> 0.0028: -0.0001 (0.97)
mozilla-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.2110 -> 0.2102: -0.0007 (1.00)
mozilla-dirstate-v2 | default-copies-clean.ignored.pbr | 0.0489 -> 0.0401: -0.0088 (0.82)
mozilla-dirstate-v2 | default-copies-clean.no-iu.pbr | 0.0479 -> 0.0393: -0.0085 (0.82)
mozilla-dirstate-v2 | default-copies-large.all.pbr | 0.1262 -> 0.1210: -0.0051 (0.96)
mozilla-dirstate-v2 | default-copies-small.ignored-unknown.pbr | 0.1262 -> 0.1200: -0.0062 (0.95)
mozilla-dirstate-v2 | default-copies-small.ignored.pbr | 0.0536 -> 0.0417: -0.0119 (0.78)
mozilla-dirstate-v2 | default-copies-small.no-iu.pbr | 0.0482 -> 0.0393: -0.0089 (0.81)
mozilla-dirstate-v2 | default-plain-clean.ignored.pbr | 0.0518 -> 0.0402: -0.0116 (0.78)
mozilla-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0481 -> 0.0392: -0.0088 (0.82)
mozilla-dirstate-v2 | default-plain-large.all.pbr | 0.1271 -> 0.1218: -0.0052 (0.96)
mozilla-dirstate-v2 | default-plain-small.ignored-unknown.pbr | 0.1225 -> 0.1202: -0.0022 (0.98)
mozilla-dirstate-v2 | default-plain-small.ignored.pbr | 0.0510 -> 0.0418: -0.0092 (0.82)
mozilla-dirstate-v2 | default-plain-small.no-iu.pbr | 0.0480 -> 0.0394: -0.0086 (0.82)
netbeans-dirstate-v1 | default-plain-clean.no-iu.pbr | 0.1442 -> 0.1422: -0.0020 (0.99)
netbeans-dirstate-v2 | default-plain-clean.no-iu.pbr | 0.0325 -> 0.0282: -0.0043 (0.87)
```
Differential Revision: https://phab.mercurial-scm.org/D12175
from __future__ import absolute_import
from __future__ import print_function
from mercurial import minifileset
def check(text, truecases, falsecases):
f = minifileset.compile(text)
for args in truecases:
if not f(*args):
print('unexpected: %r should include %r' % (text, args))
for args in falsecases:
if f(*args):
print('unexpected: %r should exclude %r' % (text, args))
check(b'all()', [(b'a.php', 123), (b'b.txt', 0)], [])
check(b'none()', [], [(b'a.php', 123), (b'b.txt', 0)])
check(b'!!!!((!(!!all())))', [], [(b'a.php', 123), (b'b.txt', 0)])
check(
b'"path:a" & (**.b | **.c)', [(b'a/b.b', 0), (b'a/c.c', 0)], [(b'b/c.c', 0)]
)
check(
b'(path:a & **.b) | **.c', [(b'a/b.b', 0), (b'a/c.c', 0), (b'b/c.c', 0)], []
)
check(
b'**.bin - size("<20B")', [(b'b.bin', 21)], [(b'a.bin', 11), (b'b.txt', 21)]
)
check(
b'!!**.bin or size(">20B") + "path:bin" or !size(">10")',
[(b'a.bin', 11), (b'b.txt', 21), (b'bin/abc', 11)],
[(b'a.notbin', 11), (b'b.txt', 11), (b'bin2/abc', 11)],
)
check(
b'(**.php and size(">10KB")) | **.zip | ("path:bin" & !"path:bin/README") '
b' | size(">1M")',
[(b'a.php', 15000), (b'a.zip', 0), (b'bin/a', 0), (b'bin/README', 1e7)],
[(b'a.php', 5000), (b'b.zip2', 0), (b't/bin/a', 0), (b'bin/README', 1)],
)