Mercurial > hg
view mercurial/changegroup.py @ 12296:d7fff529d85d
clone: only use stream when we understand the revlog format
This patch fixes issues with stream cloning in the presense of parentdelta,
lwcopy and similar additions that change the interpretation of the revlog
format, or the format itself.
Currently, the stream capability is sent like this:
stream=<version of changelog>
But the client doesn't actually check the version number; also, it only checks
the changelog and it doesn't capture the interpretation-changes and
flag-changes in parentdelta and lwcopy.
This patch removes the 'stream' capability whenever we use a non-basic revlog
format, to prevent old clients from receiving incorrect data. In those cases,
a new capability called 'streamreqs' is added instead. Instead of a revlog
version, it comes with a list of revlog-format relevant requirements, which
are a subset of the repository requirements, excluding things that are not
relevant for stream.
New clients use this to determine whether or not they can stream. Old clients
only look for the 'stream' capability, as always. New servers will still send
this when serving old repositories.
author | Sune Foldager <cryo@cyanite.org> |
---|---|
date | Wed, 15 Sep 2010 11:06:22 +0200 |
parents | bcc7139521b7 |
children | 7458de933f26 |
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# 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 or any later version. from i18n import _ import util import struct, os, bz2, zlib, tempfile def getchunk(source): """return the next chunk from changegroup 'source' as a string""" 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, progress=None): """iterate through the chunks in source, yielding a sequence of chunks (strings)""" while 1: c = getchunk(source) if not c: break elif progress is not None: progress() yield c def chunkheader(length): """return a changegroup chunk header (string)""" return struct.pack(">l", length + 4) def closechunk(): """return a changegroup chunk header (string) for a zero-length chunk""" 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 collector(cl, mmfs, files): # Gather information about changeset nodes going out in a bundle. # We want to gather manifests needed and filelogs affected. def collect(node): c = cl.read(node) files.update(c[3]) mmfs.setdefault(c[0], node) return collect # 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 decompressor(fh, alg): if alg == 'UN': return fh elif alg == 'GZ': def generator(f): zd = zlib.decompressobj() for chunk in f: yield zd.decompress(chunk) elif alg == 'BZ': def generator(f): zd = bz2.BZ2Decompressor() zd.decompress("BZ") for chunk in util.filechunkiter(f, 4096): yield zd.decompress(chunk) else: raise util.Abort("unknown bundle compression '%s'" % alg) return generator(fh) class unbundle10(object): def __init__(self, fh, alg): self._stream = util.chunkbuffer(decompressor(fh, alg)) self._type = alg def compressed(self): return self._type != 'UN' def read(self, l): return self._stream.read(l) def readbundle(fh, fname): header = fh.read(6) if not fname: fname = "stream" if not header.startswith('HG') and header.startswith('\0'): # headerless bundle, clean things up def fixup(f, h): yield h for x in f: yield x fh = fixup(fh, header) header = "HG10UN" magic, version, alg = header[0:2], header[2:4], header[4:6] if magic != 'HG': raise util.Abort(_('%s: not a Mercurial bundle') % fname) if version != '10': raise util.Abort(_('%s: unknown bundle version %s') % (fname, version)) return unbundle10(fh, alg)