revlog: fix revlogio.packentry corner case
We want to store version information about the revlog in the first
entry of its index. The code in packentry was using some heuristics
to detect whether this was the first entry, but these heuristics could
fail in some cases (e.g. rev 0 was empty; rev 1 descends directly from
the nullid and is stored as a delta).
We now give the revision number to packentry to avoid heuristics.
#!/usr/bin/env python
#
# Copyright (C) 2007 Brendan Cully <brendan@kublai.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
import os, sys
class ConfigError(Exception): pass
def usage():
print """relink <source> <destination>
Recreate hard links between source and destination repositories"""
class Config:
def __init__(self, args):
if len(args) != 3:
raise ConfigError("wrong number of arguments")
self.src = os.path.abspath(args[1])
self.dst = os.path.abspath(args[2])
for d in (self.src, self.dst):
if not os.path.exists(os.path.join(d, '.hg')):
raise ConfigError("%s: not a mercurial repository" % d)
def collect(src):
seplen = len(os.path.sep)
candidates = []
for dirpath, dirnames, filenames in os.walk(src):
relpath = dirpath[len(src) + seplen:]
for filename in filenames:
if not filename.endswith('.i'):
continue
st = os.stat(os.path.join(dirpath, filename))
candidates.append((os.path.join(relpath, filename), st))
return candidates
def prune(candidates, dst):
def getdatafile(path):
if not path.endswith('.i'):
return None, None
df = path[:-1] + 'd'
try:
st = os.stat(df)
except OSError:
return None, None
return df, st
def linkfilter(dst, st):
try:
ts = os.stat(dst)
except OSError:
# Destination doesn't have this file?
return False
if st.st_ino == ts.st_ino:
return False
if st.st_dev != ts.st_dev:
# No point in continuing
raise Exception('Source and destination are on different devices')
if st.st_size != ts.st_size:
# TODO: compare revlog heads
return False
return st
targets = []
for fn, st in candidates:
tgt = os.path.join(dst, fn)
ts = linkfilter(tgt, st)
if not ts:
continue
targets.append((fn, ts.st_size))
df, ts = getdatafile(tgt)
if df:
targets.append((fn[:-1] + 'd', ts.st_size))
return targets
def relink(src, dst, files):
def relinkfile(src, dst):
bak = dst + '.bak'
os.rename(dst, bak)
try:
os.link(src, dst)
except OSError:
os.rename(bak, dst)
raise
os.remove(bak)
CHUNKLEN = 65536
relinked = 0
savedbytes = 0
for f, sz in files:
source = os.path.join(src, f)
tgt = os.path.join(dst, f)
sfp = file(source)
dfp = file(tgt)
sin = sfp.read(CHUNKLEN)
while sin:
din = dfp.read(CHUNKLEN)
if sin != din:
break
sin = sfp.read(CHUNKLEN)
if sin:
continue
try:
relinkfile(source, tgt)
print 'Relinked %s' % f
relinked += 1
savedbytes += sz
except OSError, inst:
print '%s: %s' % (tgt, str(inst))
print 'Relinked %d files (%d bytes reclaimed)' % (relinked, savedbytes)
try:
cfg = Config(sys.argv)
except ConfigError, inst:
print str(inst)
usage()
sys.exit(1)
src = os.path.join(cfg.src, '.hg')
dst = os.path.join(cfg.dst, '.hg')
candidates = collect(src)
targets = prune(candidates, dst)
relink(src, dst, targets)