internals: refactor wire protocol documentation
Upcoming work will introduce a new version of the HTTP and SSH
transports. The differences will be significant enough to consider
them new transports. So, we now attach a version number to each
transport.
In addition, having the handshake documented after the transport
and in a single shared section made it harder to follow the flow
of the connection. The handshake documentation is now moved to the
protocol section it describes. We now have a generic section about
the purpose of the handshake, which was rewritten significantly.
Differential Revision: https://phab.mercurial-scm.org/D2060
# 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 __future__ import absolute_import
import errno
import hashlib
from .i18n import _
from .node import (
hex,
short,
)
from . import (
bundle2,
changegroup,
discovery,
error,
exchange,
obsolete,
obsutil,
util,
)
def _bundle(repo, bases, heads, node, suffix, compress=True, obsolescence=True):
"""create a bundle with the specified revisions as a backup"""
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
allcommits = repo.set('%ln::%ln', bases, heads)
allhashes = sorted(c.hex() for c in allcommits)
totalhash = hashlib.sha1(''.join(allhashes)).digest()
name = "%s/%s-%s-%s.hg" % (backupdir, short(node),
hex(totalhash[:4]), suffix)
cgversion = changegroup.localversion(repo)
comp = None
if cgversion != '01':
bundletype = "HG20"
if compress:
comp = 'BZ'
elif compress:
bundletype = "HG10BZ"
else:
bundletype = "HG10UN"
outgoing = discovery.outgoing(repo, missingroots=bases, missingheads=heads)
contentopts = {
'cg.version': cgversion,
'obsolescence': obsolescence,
'phases': True,
}
return bundle2.writenewbundle(repo.ui, repo, 'strip', name, bundletype,
outgoing, contentopts, vfs, compression=comp)
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 _collectrevlog(revlog, striprev):
_, brokenset = revlog.getstrippoint(striprev)
return [revlog.linkrev(r) for r in brokenset]
def _collectmanifest(repo, striprev):
return _collectrevlog(repo.manifestlog._revlog, striprev)
def _collectbrokencsets(repo, files, striprev):
"""return the changesets which will be broken by the truncation"""
s = set()
s.update(_collectmanifest(repo, striprev))
for fname in files:
s.update(_collectrevlog(repo.file(fname), striprev))
return s
def strip(ui, repo, nodelist, backup=True, topic='backup'):
# This function requires the caller to lock the repo, but it operates
# within a transaction of its own, and thus requires there to be no current
# transaction when it is called.
if repo.currenttransaction() is not None:
raise error.ProgrammingError('cannot strip from inside a transaction')
# 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)
files = _collectfiles(repo, striprev)
saverevs = _collectbrokencsets(repo, files, striprev)
# 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)
saveheads = set(saverevs)
for r in cl.revs(start=striprev + 1):
if any(p in tostrip for p in cl.parentrevs(r)):
tostrip.add(r)
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]
stripobsidx = obsmarkers = ()
if repo.ui.configbool('devel', 'strip-obsmarkers'):
obsmarkers = obsutil.exclusivemarkers(repo, stripbases)
if obsmarkers:
stripobsidx = [i for i, m in enumerate(repo.obsstore)
if m in obsmarkers]
# 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
node = nodelist[-1]
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))
tmpbundlefile = None
if saveheads:
# do not compress temporary bundle if we remove it from disk later
#
# We do not include obsolescence, it might re-introduce prune markers
# we are trying to strip. This is harmless since the stripped markers
# are already backed up and we did not touched the markers for the
# saved changesets.
tmpbundlefile = _bundle(repo, savebases, saveheads, node, 'temp',
compress=False, obsolescence=False)
try:
with repo.transaction("strip") as tr:
offset = len(tr.entries)
tr.startgroup()
cl.strip(striprev, tr)
stripmanifest(repo, striprev, tr, files)
for fn in files:
repo.file(fn).strip(striprev, tr)
tr.endgroup()
for i in xrange(offset, len(tr.entries)):
file, troffset, ignore = tr.entries[i]
with repo.svfs(file, 'a', checkambig=True) as fp:
fp.truncate(troffset)
if troffset == 0:
repo.store.markremoved(file)
deleteobsmarkers(repo.obsstore, stripobsidx)
del repo.obsstore
repo.invalidatevolatilesets()
repo._phasecache.filterunknown(repo)
if tmpbundlefile:
ui.note(_("adding branch\n"))
f = vfs.open(tmpbundlefile, "rb")
gen = exchange.readbundle(ui, f, tmpbundlefile, vfs)
if not repo.ui.verbose:
# silence internal shuffling chatter
repo.ui.pushbuffer()
tmpbundleurl = 'bundle:' + vfs.join(tmpbundlefile)
txnname = 'strip'
if not isinstance(gen, bundle2.unbundle20):
txnname = "strip\n%s" % util.hidepassword(tmpbundleurl)
with repo.transaction(txnname) as tr:
bundle2.applybundle(repo, gen, tr, source='strip',
url=tmpbundleurl)
if not repo.ui.verbose:
repo.ui.popbuffer()
f.close()
with repo.transaction('repair') as tr:
bmchanges = [(m, repo[newbmtarget].node()) for m in updatebm]
bm.applychanges(repo, tr, bmchanges)
# remove undo files
for undovfs, undofile in repo.undofiles():
try:
undovfs.unlink(undofile)
except OSError as e:
if e.errno != errno.ENOENT:
ui.warn(_('error removing %s: %s\n') %
(undovfs.join(undofile), str(e)))
except: # re-raises
if backupfile:
ui.warn(_("strip failed, backup bundle stored in '%s'\n")
% vfs.join(backupfile))
if tmpbundlefile:
ui.warn(_("strip failed, unrecovered changes stored in '%s'\n")
% vfs.join(tmpbundlefile))
ui.warn(_("(fix the problem, then recover the changesets with "
"\"hg unbundle '%s'\")\n") % vfs.join(tmpbundlefile))
raise
else:
if tmpbundlefile:
# Remove temporary bundle only if there were no exceptions
vfs.unlink(tmpbundlefile)
repo.destroyed()
# return the backup file path (or None if 'backup' was False) so
# extensions can use it
return backupfile
def safestriproots(ui, repo, nodes):
"""return list of roots of nodes where descendants are covered by nodes"""
torev = repo.unfiltered().changelog.rev
revs = set(torev(n) for n in nodes)
# tostrip = wanted - unsafe = wanted - ancestors(orphaned)
# orphaned = affected - wanted
# affected = descendants(roots(wanted))
# wanted = revs
tostrip = set(repo.revs('%ld-(::((roots(%ld)::)-%ld))', revs, revs, revs))
notstrip = revs - tostrip
if notstrip:
nodestr = ', '.join(sorted(short(repo[n].node()) for n in notstrip))
ui.warn(_('warning: orphaned descendants detected, '
'not stripping %s\n') % nodestr)
return [c.node() for c in repo.set('roots(%ld)', tostrip)]
class stripcallback(object):
"""used as a transaction postclose callback"""
def __init__(self, ui, repo, backup, topic):
self.ui = ui
self.repo = repo
self.backup = backup
self.topic = topic or 'backup'
self.nodelist = []
def addnodes(self, nodes):
self.nodelist.extend(nodes)
def __call__(self, tr):
roots = safestriproots(self.ui, self.repo, self.nodelist)
if roots:
strip(self.ui, self.repo, roots, self.backup, self.topic)
def delayedstrip(ui, repo, nodelist, topic=None):
"""like strip, but works inside transaction and won't strip irreverent revs
nodelist must explicitly contain all descendants. Otherwise a warning will
be printed that some nodes are not stripped.
Always do a backup. The last non-None "topic" will be used as the backup
topic name. The default backup topic name is "backup".
"""
tr = repo.currenttransaction()
if not tr:
nodes = safestriproots(ui, repo, nodelist)
return strip(ui, repo, nodes, True, topic)
# transaction postclose callbacks are called in alphabet order.
# use '\xff' as prefix so we are likely to be called last.
callback = tr.getpostclose('\xffstrip')
if callback is None:
callback = stripcallback(ui, repo, True, topic)
tr.addpostclose('\xffstrip', callback)
if topic:
callback.topic = topic
callback.addnodes(nodelist)
def stripmanifest(repo, striprev, tr, files):
revlog = repo.manifestlog._revlog
revlog.strip(striprev, tr)
striptrees(repo, tr, striprev, files)
def striptrees(repo, tr, striprev, files):
if 'treemanifest' in repo.requirements: # safe but unnecessary
# otherwise
for unencoded, encoded, size in repo.store.datafiles():
if (unencoded.startswith('meta/') and
unencoded.endswith('00manifest.i')):
dir = unencoded[5:-12]
repo.manifestlog._revlog.dirlog(dir).strip(striprev, tr)
def rebuildfncache(ui, repo):
"""Rebuilds the fncache file from repo history.
Missing entries will be added. Extra entries will be removed.
"""
repo = repo.unfiltered()
if 'fncache' not in repo.requirements:
ui.warn(_('(not rebuilding fncache because repository does not '
'support fncache)\n'))
return
with repo.lock():
fnc = repo.store.fncache
# Trigger load of fncache.
if 'irrelevant' in fnc:
pass
oldentries = set(fnc.entries)
newentries = set()
seenfiles = set()
repolen = len(repo)
for rev in repo:
ui.progress(_('rebuilding'), rev, total=repolen,
unit=_('changesets'))
ctx = repo[rev]
for f in ctx.files():
# This is to minimize I/O.
if f in seenfiles:
continue
seenfiles.add(f)
i = 'data/%s.i' % f
d = 'data/%s.d' % f
if repo.store._exists(i):
newentries.add(i)
if repo.store._exists(d):
newentries.add(d)
ui.progress(_('rebuilding'), None)
if 'treemanifest' in repo.requirements: # safe but unnecessary otherwise
for dir in util.dirs(seenfiles):
i = 'meta/%s/00manifest.i' % dir
d = 'meta/%s/00manifest.d' % dir
if repo.store._exists(i):
newentries.add(i)
if repo.store._exists(d):
newentries.add(d)
addcount = len(newentries - oldentries)
removecount = len(oldentries - newentries)
for p in sorted(oldentries - newentries):
ui.write(_('removing %s\n') % p)
for p in sorted(newentries - oldentries):
ui.write(_('adding %s\n') % p)
if addcount or removecount:
ui.write(_('%d items added, %d removed from fncache\n') %
(addcount, removecount))
fnc.entries = newentries
fnc._dirty = True
with repo.transaction('fncache') as tr:
fnc.write(tr)
else:
ui.write(_('fncache already up to date\n'))
def stripbmrevset(repo, mark):
"""
The revset to strip when strip is called with -B mark
Needs to live here so extensions can use it and wrap it even when strip is
not enabled or not present on a box.
"""
return repo.revs("ancestors(bookmark(%s)) - "
"ancestors(head() and not bookmark(%s)) - "
"ancestors(bookmark() and not bookmark(%s))",
mark, mark, mark)
def deleteobsmarkers(obsstore, indices):
"""Delete some obsmarkers from obsstore and return how many were deleted
'indices' is a list of ints which are the indices
of the markers to be deleted.
Every invocation of this function completely rewrites the obsstore file,
skipping the markers we want to be removed. The new temporary file is
created, remaining markers are written there and on .close() this file
gets atomically renamed to obsstore, thus guaranteeing consistency."""
if not indices:
# we don't want to rewrite the obsstore with the same content
return
left = []
current = obsstore._all
n = 0
for i, m in enumerate(current):
if i in indices:
n += 1
continue
left.append(m)
newobsstorefile = obsstore.svfs('obsstore', 'w', atomictemp=True)
for bytes in obsolete.encodemarkers(left, True, obsstore._version):
newobsstorefile.write(bytes)
newobsstorefile.close()
return n