contrib/convert-repo

cleanup: use the deque type where appropriate

There have been quite a few places where we pop elements off the
front of a list.  This can turn O(n) algorithms into something more
like O(n**2).  Python has provided a deque type that can do this
efficiently since at least 2.4.

As an example of the difference a deque can make, it improves
perfancestors performance on a Linux repo from 0.50 seconds to 0.36.

#!/usr/bin/env python
#
# Wrapper script around the convert.py hgext extension
# for foreign SCM conversion to mercurial format.
#

import sys
from mercurial import ui, fancyopts
from hgext import convert

# Options extracted from the cmdtable
func, options, help = convert.cmdtable['convert']

# An ui instance
u = ui.ui()

opts = {}
args = []
try:
    args = list(fancyopts.fancyopts(sys.argv[1:], options, opts))
    args += [None]*(3 - len(args))
    src, dest, revmapfile = args
except (fancyopts.getopt.GetoptError, ValueError), inst:
    u.warn('Usage:\n%s\n' % help)
    sys.exit(-1)

convert.convert(u, src, dest, revmapfile, **opts)