findrenames: Optimise "addremove -s100" by matching files by their SHA1 hashes.
We speed up 'findrenames' for the usecase when a user specifies they
want a similarity of 100% by matching files by their exact SHA1 hash
value. This reduces the number of comparisons required to find exact
matches from O(n^2) to O(n).
While it would be nice if we could just use mercurial's pre-calculated
SHA1 hash for existing files, this hash includes the file's ancestor
information making it unsuitable for our purposes. Instead, we calculate
the hash of old content from scratch.
The following benchmarks were taken on the current head of crew:
addremove 100% similarity:
rm -rf *; hg up -C; mv tests tests.new
hg --time addremove -s100 --dry-run
before: real 176.350 secs (user 128.890+0.000 sys 47.430+0.000)
after: real 2.130 secs (user 1.890+0.000 sys 0.240+0.000)
addremove 75% similarity:
rm -rf *; hg up -C; mv tests tests.new; \
for i in tests.new/*; do echo x >> $i; done
hg --time addremove -s75 --dry-run
before: real 264.560 secs (user 215.130+0.000 sys 49.410+0.000)
after: real 218.710 secs (user 172.790+0.000 sys 45.870+0.000)
#!/bin/sh
# some implementations of cp can't create hardlinks
cat > cp.py <<EOF
from mercurial import util
import sys
util.copyfiles(sys.argv[1], sys.argv[2], hardlink=True)
EOF
# test hardlinking outside hg
mkdir x
echo foo > x/a
python cp.py x y
echo bar >> y/a
echo % no diff if hardlink
diff x/a y/a
# test mq hardlinking
echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH
echo % init
hg init a
cd a
hg qimport -n foo - << EOF
# HG changeset patch
# Date 1 0
diff -r 2588a8b53d66 a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/a Wed Jul 23 15:54:29 2008 +0200
@@ -0,0 +1,1 @@
+a
EOF
hg qpush
cd ..
python cp.py a b
cd b
hg qimport -n bar - << EOF
# HG changeset patch
# Date 2 0
diff -r 2588a8b53d66 a
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/b Wed Jul 23 15:54:29 2008 +0200
@@ -0,0 +1,1 @@
+b
EOF
hg qpush
cat .hg/patches/status
echo %
cat .hg/patches/series
echo %%%
cat ../a/.hg/patches/status
echo %
cat ../a/.hg/patches/series
# test tags hardlinking
hg qdel -r qbase:qtip
hg tag -l lfoo
hg tag foo
cd ..
python cp.py b c
cd c
hg tag -l -r 0 lbar
hg tag -r 0 bar
echo %%%
cat .hgtags
echo %
cat .hg/localtags
echo %%%
cat ../b/.hgtags
echo %
cat ../b/.hg/localtags