mercurial/changegroup.py
author mason@suse.com
Tue, 04 Apr 2006 16:38:44 -0400
changeset 2076 d007df6daf8e
parent 1997 802e8a029d99
child 2470 fe1689273f84
permissions -rw-r--r--
Create an atomic opener that does not automatically rename on close The revlog.checkinlinesize() uses an atomic opener to replace the index file after converting it from inline to traditional .i and .d files. If this operation is interrupted, the atomic file class can overwrite a valid file with a partially written one. This patch introduces an atomic opener that does not automatically replace the destination file with the tempfile. This way an interrupted checkinlinesize() call turns into a noop.

"""
changegroup.py - Mercurial changegroup manipulation functions

 Copyright 2006 Matt Mackall <mpm@selenic.com>

This software may be used and distributed according to the terms
of the GNU General Public License, incorporated herein by reference.
"""
import struct
from i18n import gettext as _
from demandload import *
demandload(globals(), "util")

def getchunk(source):
    """get a chunk from a changegroup"""
    d = source.read(4)
    if not d:
        return ""
    l = struct.unpack(">l", d)[0]
    if l <= 4:
        return ""
    d = source.read(l - 4)
    if len(d) < l - 4:
        raise util.Abort(_("premature EOF reading chunk"
                           " (got %d bytes, expected %d)")
                          % (len(d), l - 4))
    return d

def chunkiter(source):
    """iterate through the chunks in source"""
    while 1:
        c = getchunk(source)
        if not c:
            break
        yield c

def genchunk(data):
    """build a changegroup chunk"""
    header = struct.pack(">l", len(data)+ 4)
    return "%s%s" % (header, data)

def closechunk():
    return struct.pack(">l", 0)