mercurial/changegroup.py
author Thomas Arendsen Hein <thomas@intevation.de>
Sat, 04 Aug 2007 22:25:12 +0200
changeset 5067 3d35c8cb5eb4
parent 3932 e0793314360e
child 5370 61462e7d62ed
permissions -rw-r--r--
Simplify/correct finding the hg executable (fixes issue644) Simply use find_exe('hg') as the default value for $HG and require to manually set it if you have special requirements. While the default will not always be 100% correct (i.e. the identical hg version) for many users it is and for the others the hg executable found in the PATH should do most things correctly. Developers or other users with multiple installs can set $HG or run something like util.set_hgexecutable in their shell or python scripts. Additionally util.hgexecutable() is now available so extensions can access the value with a public interface, too.

"""
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.
"""

from i18n import _
import struct, os, bz2, zlib, util, tempfile

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)

class nocompress(object):
    def compress(self, x):
        return x
    def flush(self):
        return ""

bundletypes = {
    "": ("", nocompress),
    "HG10UN": ("HG10UN", nocompress),
    "HG10BZ": ("HG10", lambda: bz2.BZ2Compressor()),
    "HG10GZ": ("HG10GZ", lambda: zlib.compressobj()),
}

def writebundle(cg, filename, bundletype):
    """Write a bundle file and return its filename.

    Existing files will not be overwritten.
    If no filename is specified, a temporary file is created.
    bz2 compression can be turned off.
    The bundle file will be deleted in case of errors.
    """

    fh = None
    cleanup = None
    try:
        if filename:
            fh = open(filename, "wb")
        else:
            fd, filename = tempfile.mkstemp(prefix="hg-bundle-", suffix=".hg")
            fh = os.fdopen(fd, "wb")
        cleanup = filename

        header, compressor = bundletypes[bundletype]
        fh.write(header)
        z = compressor()

        # parse the changegroup data, otherwise we will block
        # in case of sshrepo because we don't know the end of the stream

        # an empty chunkiter is the end of the changegroup
        empty = False
        while not empty:
            empty = True
            for chunk in chunkiter(cg):
                empty = False
                fh.write(z.compress(genchunk(chunk)))
            fh.write(z.compress(closechunk()))
        fh.write(z.flush())
        cleanup = None
        return filename
    finally:
        if fh is not None:
            fh.close()
        if cleanup is not None:
            os.unlink(cleanup)

def readbundle(fh, fname):
    header = fh.read(6)
    if not header.startswith("HG"):
        raise util.Abort(_("%s: not a Mercurial bundle file") % fname)
    elif not header.startswith("HG10"):
        raise util.Abort(_("%s: unknown bundle version") % fname)

    if header == "HG10BZ":
        def generator(f):
            zd = bz2.BZ2Decompressor()
            zd.decompress("BZ")
            for chunk in util.filechunkiter(f, 4096):
                yield zd.decompress(chunk)
        return util.chunkbuffer(generator(fh))
    elif header == "HG10UN":
        return fh

    raise util.Abort(_("%s: unknown bundle compression type")
                     % fname)