tests/md5sum.py

branchmap: Save changectx creation during update

The newly introduced `branchmap` function allows us to skip the
creation of changectx objects. This speeds up the construction of
the branchmap.

On the mozilla repository (117293 changesets, 15490 mutable)

Before:
  ! impactable 19.9
  ! mutable 0.576
  ! unserved 3.16

After:
  ! impactable 7.03 (2.8x faster)
  ! mutable 0.352 (1.6x)
  ! unserved 1.15 (2.7x)

On the cpython repository (81418 changesets, 6418 mutable)

Before:
  ! impactable 15.9
  ! mutable 0.451
  ! unserved 0.861

After:
  ! impactable 6.55 (2.4x faster)
  ! mutable 0.170 (2.6x faster)
  ! unserved 0.289 (2.9x faster)

On the pypy repository (58852 changesets)

Before:
  ! impactable 13.6

After:
  ! impactable 6.17 (2.2x faster)

On my Mercurial repository (18295 changesets, 2210 mutable)

Before:
  ! impactable 23.9
  ! mutable 0.368
  ! unserved 0.057

After:
  ! impactable 1.31 (18x faster)
  ! mutable 0.042 (8.7x)
  ! unserved 0.025 (2.2x)

#!/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.

import sys, os

try:
    from hashlib import md5
except ImportError:
    from md5 import 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, msg:
        sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
        sys.exit(1)

    m = md5()
    try:
        while True:
            data = fp.read(8192)
            if not data:
                break
            m.update(data)
    except IOError, 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)