--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/relink.py Thu Nov 05 17:38:03 2009 -0500
@@ -0,0 +1,149 @@
+# Mercurial extension to provide 'hg relink' command
+#
+# 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.
+
+"""recreates hardlinks between repository clones"""
+
+from mercurial import cmdutil, hg, util
+from mercurial.i18n import _
+import os, stat
+
+def relink(ui, repo, origin=None, **opts):
+ """recreate hardlinks between two repositories
+
+ When repositories are cloned locally, their data files will be hardlinked
+ so that they only use the space of a single repository.
+
+ 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.)
+ """
+ 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))
+ locallock = repo.lock()
+ try:
+ remotelock = 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:
+ remotelock.release()
+ finally:
+ locallock.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[-2:] in ('.d', '.i'):
+ continue
+ st = os.stat(os.path.join(dirpath, filename))
+ if not stat.S_ISREG(st.st_mode):
+ continue
+ candidates.append((os.path.join(relpath, filename), st))
+
+ ui.status(_('collected %d candidate storage files\n') % len(candidates))
+ return candidates
+
+def prune(candidates, dst, ui):
+ 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 util.Abort(
+ _('source and destination are on different devices'))
+ if st.st_size != ts.st_size:
+ return False
+ return st
+
+ targets = []
+ for fn, st in candidates:
+ 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))
+
+ ui.status(_('pruned down to %d probably relinkable files\n') % len(targets))
+ return targets
+
+def do_relink(src, dst, files, ui):
+ 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
+
+ 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)
+ dfp = file(tgt)
+ sin = sfp.read(CHUNKLEN)
+ while sin:
+ din = dfp.read(CHUNKLEN)
+ if sin != din:
+ break
+ sin = sfp.read(CHUNKLEN)
+ if sin:
+ ui.debug(_('not linkable: %s\n') % f)
+ continue
+ try:
+ relinkfile(source, tgt)
+ ui.progress(_('relink'), pos, f, _(' files'), total)
+ relinked += 1
+ savedbytes += sz
+ except OSError, inst:
+ ui.warn(_('%s: %s\n') % (tgt, str(inst)))
+
+ ui.status(_('relinked %d files (%d bytes reclaimed)\n') %
+ (relinked, savedbytes))
+
+cmdtable = {
+ 'relink': (
+ relink,
+ [],
+ _('[ORIGIN]')
+ )
+}