revlog: change generaldelta delta parent heuristic
The old generaldelta heuristic was "if p1 (or p2) was closer than the last full text,
use it, otherwise use prev". This was problematic when a repo contained multiple
branches that were very different. If commits to branch A were pushed, and the
last full text was branch B, it would generate a fulltext. Then if branch B was
pushed, it would generate another fulltext. The problem is that the last
fulltext (and delta'ing against `prev` in general) has no correlation with the
contents of the incoming revision, and therefore will always have degenerate
cases.
According to the blame, that algorithm was chosen to minimize the chain length.
Since there is already code that protects against that (the delta-vs-fulltext
code), and since it has been improved since the original generaldelta algorithm
went in (2011), I believe the chain length criteria will still be preserved.
The new algorithm always diffs against p1 (or p2 if it's closer), unless the
resulting delta will fail the delta-vs-fulltext check, in which case we delta
against prev.
Some before and after stats on manifest.d size.
internal large repo
old heuristic - 2.0 GB
new heuristic - 1.2 GB
mozilla-central
old heuristic - 242 MB
new heuristic - 261 MB
The regression in mozilla central is due to the new heuristic choosing p2r as
the delta when it's closer to the tip. Switching the algorithm to always prefer
p1r brings the size back down (242 MB). This is result of the way in which
mozilla does merges and pushes, and the result could easily swing the other
direction in other repos (depending on if they merge X into Y or Y into X), but
will never be as degenerate as before.
I future patch will address the regression by introducing an optional, even more
aggressive delta heuristic which will knock the mozilla manifest size down
dramatically.
# Copyright 2005, 2006 Benoit Boissinot <benoit.boissinot@ens-lyon.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''commands to sign and verify changesets'''
import os, tempfile, binascii
from mercurial import util, commands, match, cmdutil
from mercurial import node as hgnode
from mercurial.i18n import _
cmdtable = {}
command = cmdutil.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'internal' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'internal'
class gpg(object):
def __init__(self, path, key=None):
self.path = path
self.key = (key and " --local-user \"%s\"" % key) or ""
def sign(self, data):
gpgcmd = "%s --sign --detach-sign%s" % (self.path, self.key)
return util.filter(data, gpgcmd)
def verify(self, data, sig):
""" returns of the good and bad signatures"""
sigfile = datafile = None
try:
# create temporary files
fd, sigfile = tempfile.mkstemp(prefix="hg-gpg-", suffix=".sig")
fp = os.fdopen(fd, 'wb')
fp.write(sig)
fp.close()
fd, datafile = tempfile.mkstemp(prefix="hg-gpg-", suffix=".txt")
fp = os.fdopen(fd, 'wb')
fp.write(data)
fp.close()
gpgcmd = ("%s --logger-fd 1 --status-fd 1 --verify "
"\"%s\" \"%s\"" % (self.path, sigfile, datafile))
ret = util.filter("", gpgcmd)
finally:
for f in (sigfile, datafile):
try:
if f:
os.unlink(f)
except OSError:
pass
keys = []
key, fingerprint = None, None
for l in ret.splitlines():
# see DETAILS in the gnupg documentation
# filter the logger output
if not l.startswith("[GNUPG:]"):
continue
l = l[9:]
if l.startswith("VALIDSIG"):
# fingerprint of the primary key
fingerprint = l.split()[10]
elif l.startswith("ERRSIG"):
key = l.split(" ", 3)[:2]
key.append("")
fingerprint = None
elif (l.startswith("GOODSIG") or
l.startswith("EXPSIG") or
l.startswith("EXPKEYSIG") or
l.startswith("BADSIG")):
if key is not None:
keys.append(key + [fingerprint])
key = l.split(" ", 2)
fingerprint = None
if key is not None:
keys.append(key + [fingerprint])
return keys
def newgpg(ui, **opts):
"""create a new gpg instance"""
gpgpath = ui.config("gpg", "cmd", "gpg")
gpgkey = opts.get('key')
if not gpgkey:
gpgkey = ui.config("gpg", "key", None)
return gpg(gpgpath, gpgkey)
def sigwalk(repo):
"""
walk over every sigs, yields a couple
((node, version, sig), (filename, linenumber))
"""
def parsefile(fileiter, context):
ln = 1
for l in fileiter:
if not l:
continue
yield (l.split(" ", 2), (context, ln))
ln += 1
# read the heads
fl = repo.file(".hgsigs")
for r in reversed(fl.heads()):
fn = ".hgsigs|%s" % hgnode.short(r)
for item in parsefile(fl.read(r).splitlines(), fn):
yield item
try:
# read local signatures
fn = "localsigs"
for item in parsefile(repo.vfs(fn), fn):
yield item
except IOError:
pass
def getkeys(ui, repo, mygpg, sigdata, context):
"""get the keys who signed a data"""
fn, ln = context
node, version, sig = sigdata
prefix = "%s:%d" % (fn, ln)
node = hgnode.bin(node)
data = node2txt(repo, node, version)
sig = binascii.a2b_base64(sig)
keys = mygpg.verify(data, sig)
validkeys = []
# warn for expired key and/or sigs
for key in keys:
if key[0] == "ERRSIG":
ui.write(_("%s Unknown key ID \"%s\"\n")
% (prefix, shortkey(ui, key[1][:15])))
continue
if key[0] == "BADSIG":
ui.write(_("%s Bad signature from \"%s\"\n") % (prefix, key[2]))
continue
if key[0] == "EXPSIG":
ui.write(_("%s Note: Signature has expired"
" (signed by: \"%s\")\n") % (prefix, key[2]))
elif key[0] == "EXPKEYSIG":
ui.write(_("%s Note: This key has expired"
" (signed by: \"%s\")\n") % (prefix, key[2]))
validkeys.append((key[1], key[2], key[3]))
return validkeys
@command("sigs", [], _('hg sigs'))
def sigs(ui, repo):
"""list signed changesets"""
mygpg = newgpg(ui)
revs = {}
for data, context in sigwalk(repo):
node, version, sig = data
fn, ln = context
try:
n = repo.lookup(node)
except KeyError:
ui.warn(_("%s:%d node does not exist\n") % (fn, ln))
continue
r = repo.changelog.rev(n)
keys = getkeys(ui, repo, mygpg, data, context)
if not keys:
continue
revs.setdefault(r, [])
revs[r].extend(keys)
for rev in sorted(revs, reverse=True):
for k in revs[rev]:
r = "%5d:%s" % (rev, hgnode.hex(repo.changelog.node(rev)))
ui.write("%-30s %s\n" % (keystr(ui, k), r))
@command("sigcheck", [], _('hg sigcheck REV'))
def check(ui, repo, rev):
"""verify all the signatures there may be for a particular revision"""
mygpg = newgpg(ui)
rev = repo.lookup(rev)
hexrev = hgnode.hex(rev)
keys = []
for data, context in sigwalk(repo):
node, version, sig = data
if node == hexrev:
k = getkeys(ui, repo, mygpg, data, context)
if k:
keys.extend(k)
if not keys:
ui.write(_("no valid signature for %s\n") % hgnode.short(rev))
return
# print summary
ui.write("%s is signed by:\n" % hgnode.short(rev))
for key in keys:
ui.write(" %s\n" % keystr(ui, key))
def keystr(ui, key):
"""associate a string to a key (username, comment)"""
keyid, user, fingerprint = key
comment = ui.config("gpg", fingerprint, None)
if comment:
return "%s (%s)" % (user, comment)
else:
return user
@command("sign",
[('l', 'local', None, _('make the signature local')),
('f', 'force', None, _('sign even if the sigfile is modified')),
('', 'no-commit', None, _('do not commit the sigfile after signing')),
('k', 'key', '',
_('the key id to sign with'), _('ID')),
('m', 'message', '',
_('use text as commit message'), _('TEXT')),
('e', 'edit', False, _('invoke editor on commit messages')),
] + commands.commitopts2,
_('hg sign [OPTION]... [REV]...'))
def sign(ui, repo, *revs, **opts):
"""add a signature for the current or given revision
If no revision is given, the parent of the working directory is used,
or tip if no revision is checked out.
The ``gpg.cmd`` config setting can be used to specify the command
to run. A default key can be specified with ``gpg.key``.
See :hg:`help dates` for a list of formats valid for -d/--date.
"""
mygpg = newgpg(ui, **opts)
sigver = "0"
sigmessage = ""
date = opts.get('date')
if date:
opts['date'] = util.parsedate(date)
if revs:
nodes = [repo.lookup(n) for n in revs]
else:
nodes = [node for node in repo.dirstate.parents()
if node != hgnode.nullid]
if len(nodes) > 1:
raise util.Abort(_('uncommitted merge - please provide a '
'specific revision'))
if not nodes:
nodes = [repo.changelog.tip()]
for n in nodes:
hexnode = hgnode.hex(n)
ui.write(_("signing %d:%s\n") % (repo.changelog.rev(n),
hgnode.short(n)))
# build data
data = node2txt(repo, n, sigver)
sig = mygpg.sign(data)
if not sig:
raise util.Abort(_("error while signing"))
sig = binascii.b2a_base64(sig)
sig = sig.replace("\n", "")
sigmessage += "%s %s %s\n" % (hexnode, sigver, sig)
# write it
if opts['local']:
repo.vfs.append("localsigs", sigmessage)
return
if not opts["force"]:
msigs = match.exact(repo.root, '', ['.hgsigs'])
if any(repo.status(match=msigs, unknown=True, ignored=True)):
raise util.Abort(_("working copy of .hgsigs is changed "),
hint=_("please commit .hgsigs manually"))
sigsfile = repo.wfile(".hgsigs", "ab")
sigsfile.write(sigmessage)
sigsfile.close()
if '.hgsigs' not in repo.dirstate:
repo[None].add([".hgsigs"])
if opts["no_commit"]:
return
message = opts['message']
if not message:
# we don't translate commit messages
message = "\n".join(["Added signature for changeset %s"
% hgnode.short(n)
for n in nodes])
try:
editor = cmdutil.getcommiteditor(editform='gpg.sign', **opts)
repo.commit(message, opts['user'], opts['date'], match=msigs,
editor=editor)
except ValueError as inst:
raise util.Abort(str(inst))
def shortkey(ui, key):
if len(key) != 16:
ui.debug("key ID \"%s\" format error\n" % key)
return key
return key[-8:]
def node2txt(repo, node, ver):
"""map a manifest into some text"""
if ver == "0":
return "%s\n" % hgnode.hex(node)
else:
raise util.Abort(_("unknown signature version"))