tests/md5sum.py

hidden: use _domainancestors to compute revs revealed by dynamic blocker

The complexity of computing the revealed changesets is now 'O(revealed)'.
This massively speeds up the computation on large repository. Moving it to the
millisecond range.

Below are timing from two Mozilla repositories with different contents:

1) mozilla repository with:
 * 400667 changesets
 * 35 hidden changesets (first rev-268334)
 * 288 visible drafts
 * obsolete working copy (dynamicblockers),

Before:
! visible
! wall 0.030247 comb 0.030000 user 0.030000 sys 0.000000 (best of 100)

After:
! visible
! wall 0.000585 comb 0.000000 user 0.000000 sys 0.000000 (best of 4221)

The timing above include the computation of obsolete changeset:
! obsolete
! wall 0.000396 comb 0.000000 user 0.000000 sys 0.000000 (best of 6816)

So adjusted time give 30ms before versus 0.2ms after. A 150x speedup.

2) mozilla repository with:
 * 405645 changesets
 * 4312 hidden changesets (first rev-326004)
 * 264 visible drafts
 * obsolete working copy (dynamicblockers),

Before:
! visible
! wall 0.168658 comb 0.170000 user 0.170000 sys 0.000000 (best of 48)

After
! visible
! wall 0.008612 comb 0.010000 user 0.010000 sys 0.000000 (best of 325)

The timing above include the computation of obsolete changeset:
! obsolete
! wall 0.006408 comb 0.010000 user 0.010000 sys 0.000000 (best of 404)

So adjusted time give 160ms before versus 2ms after. A 75x speedup.

#!/usr/bin/env python
#
# Based on python's Tools/scripts/md5sum.py
#
# This software may be used and distributed according to the terms
# of the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2, which is
# GPL-compatible.

from __future__ import absolute_import

import os
import sys

try:
    import hashlib
    md5 = hashlib.md5
except ImportError:
    import md5
    md5 = md5.md5

try:
    import msvcrt
    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

for filename in sys.argv[1:]:
    try:
        fp = open(filename, 'rb')
    except IOError as msg:
        sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
        sys.exit(1)

    m = md5()
    try:
        for data in iter(lambda: fp.read(8192), ''):
            m.update(data)
    except IOError as msg:
        sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
        sys.exit(1)
    sys.stdout.write('%s  %s\n' % (m.hexdigest(), filename))

sys.exit(0)