ref: c57c8919e303aaad512a5e603f60d4be22d6afea
dir: /sys/src/cmd/hg/contrib/hg-relink/
#!/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 version 2, 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)