[PATCH 2 of 2] Issue919: add a standard extension to recreate hardlinks between repositories
Jesse Glick
typrase at gmail.com
Thu Nov 5 15:48:22 CST 2009
# HG changeset patch
# User Jesse Glick <jesse.glick at sun.com>
# Date 1257457250 18000
# Node ID 7327f8bdbf136b4a85767f260a63c3154e68d48e
# Parent 1308731835ae484a708ec42bae6ebc692970d0f0
Issue919: add a standard extension to recreate hardlinks between repositories.
Having to run a standalone Python script from the contrib dir is a nuisance.
Also makes various improvements to locking, file discovery, etc.
Should also update: http://www.selenic.com/mercurial/wiki/index.cgi/RecreateHardlinksBetweenRepositories
diff --git a/contrib/hg-relink b/hgext/relink.py
rename from contrib/hg-relink
rename to hgext/relink.py
--- a/contrib/hg-relink
+++ b/hgext/relink.py
@@ -1,52 +1,72 @@
-#!/usr/bin/env python
+# Mercurial extension to provide 'hg relink' command
#
# Copyright (C) 2007 Brendan Cully <brendan at 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
+"""recreates hardlinks between repository clones"""
-class ConfigError(Exception): pass
+from mercurial import cmdutil, hg, util
+from mercurial.i18n import _
+import os, stat
-def usage():
- print """relink <source> <destination>
- Recreate hard links between source and destination repositories"""
+def relink(ui, repo, origin=None, **opts):
+ """recreate hardlinks between two 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)
+ When repositories are cloned locally, their data files will be hardlinked
+ so that they only use the space of a single repository.
-def collect(src):
+ Unfortunately, subsequent pulls into either repository will break hardlinks
+ for any files touched by the new changesets, even if both repositories end
+ up pulling the same changes.
+
+ Similarly, passing --rev to "hg clone" will fail to use
+ any hardlinks, falling back to a complete copy of the source repository.
+
+ This command lets you recreate those hardlinks and reclaim that wasted
+ space.
+
+ This repository will be relinked to share space with ORIGIN, which must be
+ on the same local disk. If ORIGIN is omitted, looks for "default-relink",
+ then "default", in [paths].
+
+ Do not attempt any read operations on this repository while the command is
+ running. (Both repositories will be locked against writes.)
+ """
+ lock1 = repo.lock()
+ try:
+ src = hg.repository(
+ cmdutil.remoteui(repo, opts),
+ ui.expandpath(origin or 'default-relink', origin or 'default'))
+ if not src.local():
+ raise util.Abort('must specify local origin repository')
+ ui.status(_('Relinking %s to %s\n') % (src.store.path, repo.store.path))
+ lock2 = src.lock()
+ try:
+ candidates = collect(src.store.path, ui)
+ targets = prune(candidates, repo.store.path, ui)
+ do_relink(src.store.path, repo.store.path, targets, ui)
+ finally:
+ lock2.release()
+ finally:
+ lock1.release()
+
+def collect(src, ui):
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))
+ if filename[-2:] in ('.d', '.i'):
+ st = os.stat(os.path.join(dirpath, filename))
+ if stat.S_ISREG(st.st_mode):
+ candidates.append((os.path.join(relpath, filename), st))
+ ui.status(_('Collected %d candidate storage files\n') % len(candidates))
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 prune(candidates, dst, ui):
def linkfilter(dst, st):
try:
ts = os.stat(dst)
@@ -57,9 +77,9 @@
return False
if st.st_dev != ts.st_dev:
# No point in continuing
- raise Exception('Source and destination are on different devices')
+ raise util.Abort(
+ _('Source and destination are on different devices'))
if st.st_size != ts.st_size:
- # TODO: compare revlog heads
return False
return st
@@ -68,15 +88,14 @@
tgt = os.path.join(dst, fn)
ts = linkfilter(tgt, st)
if not ts:
+ ui.debug(_('not linkable: %s\n') % fn)
continue
targets.append((fn, ts.st_size))
- df, ts = getdatafile(tgt)
- if df:
- targets.append((fn[:-1] + 'd', ts.st_size))
+ ui.status(_('Pruned down to %d probably relinkable files\n') % len(targets))
return targets
-def relink(src, dst, files):
+def do_relink(src, dst, files, ui):
def relinkfile(src, dst):
bak = dst + '.bak'
os.rename(dst, bak)
@@ -91,7 +110,10 @@
relinked = 0
savedbytes = 0
+ pos = 0
+ total = len(files)
for f, sz in files:
+ pos += 1
source = os.path.join(src, f)
tgt = os.path.join(dst, f)
sfp = file(source)
@@ -103,26 +125,23 @@
break
sin = sfp.read(CHUNKLEN)
if sin:
+ ui.debug(_('not linkable: %s\n') % f)
continue
try:
relinkfile(source, tgt)
- print 'Relinked %s' % f
+ ui.progress(_('relink'), pos, f, _(' files'), total)
relinked += 1
savedbytes += sz
except OSError, inst:
- print '%s: %s' % (tgt, str(inst))
+ ui.warn(_('%s: %s\n') % (tgt, str(inst)))
- print 'Relinked %d files (%d bytes reclaimed)' % (relinked, savedbytes)
+ ui.status(_('Relinked %d files (%d bytes reclaimed)\n') %
+ (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)
+cmdtable = {
+ 'relink': (
+ relink,
+ [],
+ _('[ORIGIN]')
+ )
+}
diff --git a/mercurial/hg.py b/mercurial/hg.py
--- a/mercurial/hg.py
+++ b/mercurial/hg.py
@@ -225,6 +225,9 @@
if src_repo.cancopy() and islocal(dest):
abspath = os.path.abspath(util.drop_scheme('file', origsource))
copy = not pull and not rev
+ if rev and not pull:
+ ui.warn(_("--rev implies --pull; "
+ "use relink extension to reclaim hardlinks\n"))
if copy:
try:
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