tests/test-context.py

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.)

import os
from mercurial import hg, ui, context, encoding

u = ui.ui()

repo = hg.repository(u, 'test1', create=1)
os.chdir('test1')

# create 'foo' with fixed time stamp
f = open('foo', 'w')
f.write('foo\n')
f.close()
os.utime('foo', (1000, 1000))

# add+commit 'foo'
repo[None].add(['foo'])
repo.commit(text='commit1', date="0 0")

print "workingfilectx.date =", repo[None]['foo'].date()

# test memctx with non-ASCII commit message

def filectxfn(repo, memctx, path):
    return context.memfilectx("foo", "")

ctx = context.memctx(repo, ['tip', None],
                     encoding.tolocal("Gr\xc3\xbcezi!"),
                     ["foo"], filectxfn)
ctx.commit()
for enc in "ASCII", "Latin-1", "UTF-8":
    encoding.encoding = enc
    print "%-8s: %s" % (enc, repo["tip"].description())