view contrib/rewrite-log @ 8330:7de68012f86e

Windows: improve performance via buffered I/O

The posixfile_nt code hits the win32 file API directly, which
essentially amounts to performing a system call for every read and
write. This is slow.

We add a C extension that lets us use a Python file object instead,
but preserve our desired POSIX-like semantics (the ability to rename
or delete a file that is being accessed).

If the C extension is not available (e.g. in a VPS environment
without a compiler), we fall back to the posixfile_nt code.

#!/usr/bin/env python
import sys, os
from mercurial import revlog, transaction, node, util

f = sys.argv[1]

r1 = revlog.revlog(util.opener(os.getcwd(), audit=False), f + ".i", f + ".d")
r2 = revlog.revlog(util.opener(os.getcwd(), audit=False), f + ".i2", f + ".d2")

tr = transaction.transaction(sys.stderr.write, 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")