util._matcher: speed up regexp matching.
In 4babaa52badf, Benoit made a change that substantially slows matching
when a big .hgignore file is in play, because it calls into the regexp
matching engine potentially hundreds of times per file to be matched.
I've partly rolled back his change, so that we only call into the matcher
once per file, but preserved the ability to report a meaningful error
message if there's a syntax error in the regexp.
#!/bin/sh
cat >> readlink.py <<EOF
import os
import sys
for f in sys.argv[1:]:
print f, '->', os.readlink(f)
EOF
hg init a
cd a
ln -s nothing dangling
hg add dangling
hg commit -m 'add symlink' -d '0 0'
hg tip -v
hg manifest --debug
echo '% rev 0:'
python ../readlink.py dangling
rm dangling
ln -s void dangling
hg commit -m 'change symlink'
echo '% rev 1:'
python ../readlink.py dangling
echo '% modifying link'
rm dangling
ln -s empty dangling
python ../readlink.py dangling
echo '% reverting to rev 0:'
hg revert -r 0 -a
python ../readlink.py dangling
echo '% backups:'
python ../readlink.py *.orig
rm *.orig
hg up -C
echo '% copies'
hg cp -v dangling dangling2
hg st -Cmard
python ../readlink.py dangling dangling2