rewrite-log

http server: support persistent connections.

only "hg serve" affected yet.  http server running cgi script will not
use persistent connections.  support for fastcgi will help that.

clients that support keepalive can use one tcp connection for all
commands during clone and pull.  this makes latency of binary search
during pull much lower over wan.

if server does not know content-length, it will force connection to
close at end.  right fix is to use chunked transfer-encoding but this is
easier and does not hurt performance. only command that is affected is
"changegroup" which is always last command during a pull.

#!/usr/bin/env python
import sys, os
from mercurial import hg

f = sys.argv[1]

r1 = hg.revlog(open, f + ".i", f + ".d")
r2 = hg.revlog(open, f + ".i2", f + ".d2")

tr = hg.transaction(open, "journal")

for i in xrange(r1.count()):
    n = r1.node(i)
    p1, p2 = r1.parents(n)
    l = r1.linkrev(n)
    t = r1.revision(n)
    n2 = r2.addrevision(t, tr, l, p1, p2)
tr.close()

os.rename(f + ".i", f + ".i.old")
os.rename(f + ".d", f + ".d.old")
os.rename(f + ".i2", f + ".i")
os.rename(f + ".d2", f + ".d")