revisionbranchcache: fall back to slow path if starting readonly (
issue4531)
Transitioning to Mercurial versions with revision branch cache could be slow as
long as all operations were readonly (revset queries) and the cache would be
populated but not written back.
Instead, fall back to using the consistently slow path when readonly and the
cache doesn't exist yet. That avoids the overhead of populating the cache
without writing it back.
If not readonly, it will still populate all missing entries initially. That
avoids repeated writing of the cache file with small updates, and it also makes
sure a fully populated cache available for the readonly operations.
# repair.py - functions for repository repair for mercurial
#
# Copyright 2005, 2006 Chris Mason <mason@suse.com>
# Copyright 2007 Matt Mackall
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from mercurial import changegroup, exchange, util, bundle2
from mercurial.node import short, hex
from mercurial.i18n import _
import errno
def _bundle(repo, bases, heads, node, suffix, compress=True):
"""create a bundle with the specified revisions as a backup"""
usebundle2 = (repo.ui.config('experimental', 'bundle2-exp') and
repo.ui.config('experimental', 'strip-bundle2-version'))
if usebundle2:
cgversion = repo.ui.config('experimental', 'strip-bundle2-version')
if cgversion not in changegroup.packermap:
repo.ui.warn(_('unknown strip-bundle2-version value %r; ' +
'should be one of %r\n') %
(cgversion, sorted(changegroup.packermap.keys()),))
cgversion = '01'
usebundle2 = False
else:
cgversion = '01'
cg = changegroup.changegroupsubset(repo, bases, heads, 'strip',
version=cgversion)
backupdir = "strip-backup"
vfs = repo.vfs
if not vfs.isdir(backupdir):
vfs.mkdir(backupdir)
# Include a hash of all the nodes in the filename for uniqueness
hexbases = (hex(n) for n in bases)
hexheads = (hex(n) for n in heads)
allcommits = repo.set('%ls::%ls', hexbases, hexheads)
allhashes = sorted(c.hex() for c in allcommits)
totalhash = util.sha1(''.join(allhashes)).hexdigest()
name = "%s/%s-%s-%s.hg" % (backupdir, short(node), totalhash[:8], suffix)
if usebundle2:
bundletype = "HG2Y"
elif compress:
bundletype = "HG10BZ"
else:
bundletype = "HG10UN"
return changegroup.writebundle(repo.ui, cg, name, bundletype, vfs)
def _collectfiles(repo, striprev):
"""find out the filelogs affected by the strip"""
files = set()
for x in xrange(striprev, len(repo)):
files.update(repo[x].files())
return sorted(files)
def _collectbrokencsets(repo, files, striprev):
"""return the changesets which will be broken by the truncation"""
s = set()
def collectone(revlog):
_, brokenset = revlog.getstrippoint(striprev)
s.update([revlog.linkrev(r) for r in brokenset])
collectone(repo.manifest)
for fname in files:
collectone(repo.file(fname))
return s
def strip(ui, repo, nodelist, backup=True, topic='backup'):
# Simple way to maintain backwards compatibility for this
# argument.
if backup in ['none', 'strip']:
backup = False
repo = repo.unfiltered()
repo.destroying()
cl = repo.changelog
# TODO handle undo of merge sets
if isinstance(nodelist, str):
nodelist = [nodelist]
striplist = [cl.rev(node) for node in nodelist]
striprev = min(striplist)
# Some revisions with rev > striprev may not be descendants of striprev.
# We have to find these revisions and put them in a bundle, so that
# we can restore them after the truncations.
# To create the bundle we use repo.changegroupsubset which requires
# the list of heads and bases of the set of interesting revisions.
# (head = revision in the set that has no descendant in the set;
# base = revision in the set that has no ancestor in the set)
tostrip = set(striplist)
for rev in striplist:
for desc in cl.descendants([rev]):
tostrip.add(desc)
files = _collectfiles(repo, striprev)
saverevs = _collectbrokencsets(repo, files, striprev)
# compute heads
saveheads = set(saverevs)
for r in xrange(striprev + 1, len(cl)):
if r not in tostrip:
saverevs.add(r)
saveheads.difference_update(cl.parentrevs(r))
saveheads.add(r)
saveheads = [cl.node(r) for r in saveheads]
# compute base nodes
if saverevs:
descendants = set(cl.descendants(saverevs))
saverevs.difference_update(descendants)
savebases = [cl.node(r) for r in saverevs]
stripbases = [cl.node(r) for r in tostrip]
# For a set s, max(parents(s) - s) is the same as max(heads(::s - s)), but
# is much faster
newbmtarget = repo.revs('max(parents(%ld) - (%ld))', tostrip, tostrip)
if newbmtarget:
newbmtarget = repo[newbmtarget.first()].node()
else:
newbmtarget = '.'
bm = repo._bookmarks
updatebm = []
for m in bm:
rev = repo[bm[m]].rev()
if rev in tostrip:
updatebm.append(m)
# create a changegroup for all the branches we need to keep
backupfile = None
vfs = repo.vfs
if backup:
backupfile = _bundle(repo, stripbases, cl.heads(), node, topic)
repo.ui.status(_("saved backup bundle to %s\n") %
vfs.join(backupfile))
repo.ui.log("backupbundle", "saved backup bundle to %s\n",
vfs.join(backupfile))
if saveheads or savebases:
# do not compress partial bundle if we remove it from disk later
chgrpfile = _bundle(repo, savebases, saveheads, node, 'temp',
compress=False)
mfst = repo.manifest
tr = repo.transaction("strip")
offset = len(tr.entries)
try:
tr.startgroup()
cl.strip(striprev, tr)
mfst.strip(striprev, tr)
for fn in files:
repo.file(fn).strip(striprev, tr)
tr.endgroup()
try:
for i in xrange(offset, len(tr.entries)):
file, troffset, ignore = tr.entries[i]
repo.svfs(file, 'a').truncate(troffset)
if troffset == 0:
repo.store.markremoved(file)
tr.close()
except: # re-raises
tr.abort()
raise
if saveheads or savebases:
ui.note(_("adding branch\n"))
f = vfs.open(chgrpfile, "rb")
gen = exchange.readbundle(ui, f, chgrpfile, vfs)
if not repo.ui.verbose:
# silence internal shuffling chatter
repo.ui.pushbuffer()
if isinstance(gen, bundle2.unbundle20):
tr = repo.transaction('strip')
try:
bundle2.processbundle(repo, gen, lambda: tr)
tr.close()
finally:
tr.release()
else:
changegroup.addchangegroup(repo, gen, 'strip',
'bundle:' + vfs.join(chgrpfile),
True)
if not repo.ui.verbose:
repo.ui.popbuffer()
f.close()
# remove undo files
for undovfs, undofile in repo.undofiles():
try:
undovfs.unlink(undofile)
except OSError, e:
if e.errno != errno.ENOENT:
ui.warn(_('error removing %s: %s\n') %
(undovfs.join(undofile), str(e)))
for m in updatebm:
bm[m] = repo[newbmtarget].node()
bm.write()
except: # re-raises
if backupfile:
ui.warn(_("strip failed, full bundle stored in '%s'\n")
% vfs.join(backupfile))
elif saveheads:
ui.warn(_("strip failed, partial bundle stored in '%s'\n")
% vfs.join(chgrpfile))
raise
else:
if saveheads or savebases:
# Remove partial backup only if there were no exceptions
vfs.unlink(chgrpfile)
repo.destroyed()