matcher: use re2 bindings if available
There are two sets of Python re2 bindings available on the internet;
this code works with both.
Using re2 can greatly improve "hg status" performance when a .hgignore
file becomes even modestly complex.
Example: "hg status" on a clean tree with 134K files, where "hg
debugignore" reports a regexp 4256 bytes in size.
no .hgignore: 1.76 sec
Python re: 2.79
re2: 1.82
The overhead of regexp matching drops from 1.03 seconds with stock
re to 0.06 with re2.
(For comparison, a git repo with the same contents and .gitignore
file runs "git status -s" in 1.71 seconds, i.e. only slightly faster
than hg with re2.)
$ "$TESTDIR/hghave" inotify || exit 80
$ hg init
$ touch a b c d e f
$ echo "[extensions]" >> $HGRCPATH
$ echo "inotify=" >> $HGRCPATH
inserve
$ hg inserve -d --pid-file=hg.pid 2>&1
$ cat hg.pid >> "$DAEMON_PIDS"
$ hg ci -Am m
adding a
adding b
adding c
adding d
adding e
adding f
adding hg.pid
let the daemon finish its stuff
$ sleep 1
eed to test all file opperations
$ hg rm a
$ rm b
$ echo c >> c
$ touch g
$ hg add g
$ hg mv e h
$ hg status
M c
A g
A h
R a
R e
! b
$ sleep 1
Are we able to kill the service? if not, the service died on some error
$ kill `cat hg.pid`