histedit: replace various nodes lists with replacement graph (and issue3582)
This changeset rewrites the change tracking logic of histedit to record every
operation it does. Tracked operations record the full list of "old" node that
will eventually be removed to the list of new nodes that replace it. Operations
on temporary nodes are tracked too. Dropped changesets are also recorded as an
"old" node replacement by nothing. This logic is similar to the obsolescence
marker one and will be used for this purpose in later commit.
This new logic implies a big amount of change in the histedit code base.
histedit action functions now always return a tuple of
(new-ctx, [list of rewriting operations])
The old `created`, `replaced` and `tmpnodes` are no longer returned and stored
during histedit operation. When such information is necessary it is computed
from the replacement graph. This computation is done in the `processreplacement`
function.
The `replacemap` is also dropped. It is computed at the end of the command from the
graph. The `bootstrapcontinue` methods are altered to compute this different kind of
information.
This new mechanism requires much less information to be written on disk.
Note:
This changes allows a more accurate bookmark movement. bookmark on dropped
changeset are now move of their parent (or replacement of their parent)
instead of their children.
This fix issue3582
# 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 _
from node import nullrev
import mdiff, util
import struct, os, bz2, zlib, tempfile
_BUNDLE10_DELTA_HEADER = "20s20s20s20s"
def readexactly(stream, n):
'''read n bytes from stream.read and abort if less was available'''
s = stream.read(n)
if len(s) < n:
raise util.Abort(_("stream ended unexpectedly"
" (got %d bytes, expected %d)")
% (len(s), n))
return s
def getchunk(stream):
"""return the next chunk from stream as a string"""
d = readexactly(stream, 4)
l = struct.unpack(">l", d)[0]
if l <= 4:
if l:
raise util.Abort(_("invalid chunk length %d") % l)
return ""
return readexactly(stream, l - 4)
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), # only when using unbundle on ssh and old http servers
# since the unification ssh accepts a header but there
# is no capability signaling it.
"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 chunkgroup is the end of the changegroup
# a changegroup has at least 2 chunkgroups (changelog and manifest).
# after that, an empty chunkgroup is the end of the changegroup
empty = False
count = 0
while not empty or count <= 2:
empty = True
count += 1
while True:
chunk = getchunk(cg)
if not chunk:
break
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 util.filechunkiter(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 util.chunkbuffer(generator(fh))
class unbundle10(object):
deltaheader = _BUNDLE10_DELTA_HEADER
deltaheadersize = struct.calcsize(deltaheader)
def __init__(self, fh, alg):
self._stream = decompressor(fh, alg)
self._type = alg
self.callback = None
def compressed(self):
return self._type != 'UN'
def read(self, l):
return self._stream.read(l)
def seek(self, pos):
return self._stream.seek(pos)
def tell(self):
return self._stream.tell()
def close(self):
return self._stream.close()
def chunklength(self):
d = readexactly(self._stream, 4)
l = struct.unpack(">l", d)[0]
if l <= 4:
if l:
raise util.Abort(_("invalid chunk length %d") % l)
return 0
if self.callback:
self.callback()
return l - 4
def changelogheader(self):
"""v10 does not have a changelog header chunk"""
return {}
def manifestheader(self):
"""v10 does not have a manifest header chunk"""
return {}
def filelogheader(self):
"""return the header of the filelogs chunk, v10 only has the filename"""
l = self.chunklength()
if not l:
return {}
fname = readexactly(self._stream, l)
return dict(filename=fname)
def _deltaheader(self, headertuple, prevnode):
node, p1, p2, cs = headertuple
if prevnode is None:
deltabase = p1
else:
deltabase = prevnode
return node, p1, p2, deltabase, cs
def deltachunk(self, prevnode):
l = self.chunklength()
if not l:
return {}
headerdata = readexactly(self._stream, self.deltaheadersize)
header = struct.unpack(self.deltaheader, headerdata)
delta = readexactly(self._stream, l - self.deltaheadersize)
node, p1, p2, deltabase, cs = self._deltaheader(header, prevnode)
return dict(node=node, p1=p1, p2=p2, cs=cs,
deltabase=deltabase, delta=delta)
class headerlessfixup(object):
def __init__(self, fh, h):
self._h = h
self._fh = fh
def read(self, n):
if self._h:
d, self._h = self._h[:n], self._h[n:]
if len(d) < n:
d += readexactly(self._fh, n - len(d))
return d
return readexactly(self._fh, n)
def readbundle(fh, fname):
header = readexactly(fh, 6)
if not fname:
fname = "stream"
if not header.startswith('HG') and header.startswith('\0'):
fh = headerlessfixup(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)
class bundle10(object):
deltaheader = _BUNDLE10_DELTA_HEADER
def __init__(self, lookup):
self._lookup = lookup
def close(self):
return closechunk()
def fileheader(self, fname):
return chunkheader(len(fname)) + fname
def revchunk(self, revlog, rev, prev):
node = revlog.node(rev)
p1, p2 = revlog.parentrevs(rev)
base = prev
prefix = ''
if base == nullrev:
delta = revlog.revision(node)
prefix = mdiff.trivialdiffheader(len(delta))
else:
delta = revlog.revdiff(base, rev)
linknode = self._lookup(revlog, node)
p1n, p2n = revlog.parents(node)
basenode = revlog.node(base)
meta = self.builddeltaheader(node, p1n, p2n, basenode, linknode)
meta += prefix
l = len(meta) + len(delta)
yield chunkheader(l)
yield meta
yield delta
def builddeltaheader(self, node, p1n, p2n, basenode, linknode):
# do nothing with basenode, it is implicitly the previous one in HG10
return struct.pack(self.deltaheader, node, p1n, p2n, linknode)