ref: 412cbf67f18c6ce5eab580ee81b06b983d6e1ff2
dir: /sys/lib/python/mercurial/changegroup.py/
# 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 version 2, incorporated herein by reference.
from i18n import _
import util
import struct, os, bz2, zlib, 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 chunkheader(length):
"""build a changegroup chunk header"""
return struct.pack(">l", length + 4)
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()),
}
# hgweb uses this list to communicate its preferred type
bundlepriority = ['HG10GZ', 'HG10BZ', 'HG10UN']
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
# a changegroup has at least 2 chunkiters (changelog and manifest).
# after that, an empty chunkiter is the end of the changegroup
empty = False
count = 0
while not empty or count <= 2:
empty = True
count += 1
for chunk in chunkiter(cg):
empty = False
fh.write(z.compress(chunkheader(len(chunk))))
pos = 0
while pos < len(chunk):
next = pos + 2**20
fh.write(z.compress(chunk[pos:next]))
pos = next
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 unbundle(header, fh):
if header == 'HG10UN':
return fh
elif not header.startswith('HG'):
# old client with uncompressed bundle
def generator(f):
yield header
for chunk in f:
yield chunk
elif header == 'HG10GZ':
def generator(f):
zd = zlib.decompressobj()
for chunk in f:
yield zd.decompress(chunk)
elif 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))
def readbundle(fh, fname):
header = fh.read(6)
if not header.startswith('HG'):
raise util.Abort(_('%s: not a Mercurial bundle file') % fname)
if not header.startswith('HG10'):
raise util.Abort(_('%s: unknown bundle version') % fname)
elif header not in bundletypes:
raise util.Abort(_('%s: unknown bundle compression type') % fname)
return unbundle(header, fh)