mercurial/changegroup.py
author Colin McMillen <mcmillen@cs.cmu.edu>
Sun, 30 Apr 2006 22:43:41 +0200
changeset 2168 dd4ec4576cc8
parent 1997 802e8a029d99
child 2470 fe1689273f84
permissions -rw-r--r--
Proper check to see if zip dest needs to be wrapped in tellable From hgweb, calling archival.zipit fails with the error message "Illegal seek". This happens because sys.stdout.tell() throws an exception: Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/mercurial/archival.py", line 99, in addfile self.z.writestr(i, data) File "/usr/lib/python2.4/zipfile.py", line 468, in writestr zinfo.header_offset = self.fp.tell() # Start of header bytes Checking whether hasattr(dest, 'tell') is insufficient, because sys.stdout has a tell() method; you just can't call it. This patch instead determines whether a fileobj is tellable by trying to tell(), wrapping the fileobj if an exception is generated.

"""
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)