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
mkdir t
cd t
hg init
echo "added file1" > file1
echo "another line of text" >> file1
echo "added file2" > file2
hg add file1 file2
hg commit -m "added file1 and file2" -d "1000000 0" -u user
echo "changed file1" >> file1
hg commit -m "changed file1" -d "1000000 0" -u user
hg -q log
hg id
hg update -C 0
hg id
echo "changed file1" >> file1
hg id
hg revert --no-backup --all
hg diff
hg status
hg id
hg update
hg diff
hg status
hg id
hg update -C 0
echo "changed file1 different" >> file1
hg update
hg diff --nodates | sed -e "s/\(<<<<<<<\) .*/\1/" -e "s/\(>>>>>>>\) .*/\1/"
hg status
hg id
hg revert --no-backup --all
hg diff
hg status
hg id
hg revert -r tip --no-backup --all
hg diff
hg status
hg id
hg update -C
hg diff
hg status
hg id