revlog: use compression engine APIs for decompression
Now that compression engines declare their header in revlog chunks
and can decompress revlog chunks, we refactor revlog.decompress()
to use them.
Making full use of the property that revlog compressor objects are
reusable, revlog instances now maintain a dict mapping an engine's
revlog header to a compressor object. This is not only a performance
optimization for engines where compressor object reuse can result in
better performance, but it also serves as a cache of header values
so we don't need to perform redundant lookups against the compression
engine manager. (Yes, I measured and the overhead of a function call
versus a dict lookup was observed.)
Replacing the previous inline lookup table with a dict lookup was
measured to make chunk reading ~2.5% slower on changelogs and ~4.5%
slower on manifests. So, the inline lookup table has been mostly
preserved so we don't lose performance. This is unfortunate. But
many decompression operations complete in microseconds, so Python
attribute lookup, dict lookup, and function calls do matter.
The impact of this change on mozilla-unified is as follows:
$ hg perfrevlogchunks -c
! chunk
! wall 1.953663 comb 1.950000 user 1.920000 sys 0.030000 (best of 6)
! wall 1.946000 comb 1.940000 user 1.910000 sys 0.030000 (best of 6)
! chunk batch
! wall 1.791075 comb 1.800000 user 1.760000 sys 0.040000 (best of 6)
! wall 1.785690 comb 1.770000 user 1.750000 sys 0.020000 (best of 6)
$ hg perfrevlogchunks -m
! chunk
! wall 2.587262 comb 2.580000 user 2.550000 sys 0.030000 (best of 4)
! wall 2.616330 comb 2.610000 user 2.560000 sys 0.050000 (best of 4)
! chunk batch
! wall 2.427092 comb 2.420000 user 2.400000 sys 0.020000 (best of 5)
! wall 2.462061 comb 2.460000 user 2.400000 sys 0.060000 (best of 4)
Changelog chunk reading is slightly faster but manifest reading is
slower. What gives?
On this repo, 99.85% of changelog entries are zlib compressed (the 'x'
header). On the manifest, 67.5% are zlib and 32.4% are '\0'. This patch
swapped the test order of 'x' and '\0' so now 'x' is tested first. This
makes changelogs faster since they almost always hit the first branch.
This makes a significant percentage of manifest '\0' chunks slower
because that code path now performs an extra test. Yes, I too can't
believe we're able to measure the impact of an if..elif with simple
string compares. I reckon this code would benefit from being written
in C...
# verify.py - repository integrity checking for Mercurial
#
# Copyright 2006, 2007 Matt Mackall <mpm@selenic.com>
#
# 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 os
from .i18n import _
from .node import (
nullid,
short,
)
from . import (
error,
revlog,
util,
)
def verify(repo):
with repo.lock():
return verifier(repo).verify()
def _normpath(f):
# under hg < 2.4, convert didn't sanitize paths properly, so a
# converted repo may contain repeated slashes
while '//' in f:
f = f.replace('//', '/')
return f
def _validpath(repo, path):
"""Returns False if a path should NOT be treated as part of a repo.
For all in-core cases, this returns True, as we have no way for a
path to be mentioned in the history but not actually be
relevant. For narrow clones, this is important because many
filelogs will be missing, and changelog entries may mention
modified files that are outside the narrow scope.
"""
return True
class verifier(object):
def __init__(self, repo):
self.repo = repo.unfiltered()
self.ui = repo.ui
self.badrevs = set()
self.errors = 0
self.warnings = 0
self.havecl = len(repo.changelog) > 0
self.havemf = len(repo.manifestlog._revlog) > 0
self.revlogv1 = repo.changelog.version != revlog.REVLOGV0
self.lrugetctx = util.lrucachefunc(repo.changectx)
self.refersmf = False
self.fncachewarned = False
def warn(self, msg):
self.ui.warn(msg + "\n")
self.warnings += 1
def err(self, linkrev, msg, filename=None):
if linkrev is not None:
self.badrevs.add(linkrev)
else:
linkrev = '?'
msg = "%s: %s" % (linkrev, msg)
if filename:
msg = "%s@%s" % (filename, msg)
self.ui.warn(" " + msg + "\n")
self.errors += 1
def exc(self, linkrev, msg, inst, filename=None):
if not str(inst):
inst = repr(inst)
self.err(linkrev, "%s: %s" % (msg, inst), filename)
def checklog(self, obj, name, linkrev):
if not len(obj) and (self.havecl or self.havemf):
self.err(linkrev, _("empty or missing %s") % name)
return
d = obj.checksize()
if d[0]:
self.err(None, _("data length off by %d bytes") % d[0], name)
if d[1]:
self.err(None, _("index contains %d extra bytes") % d[1], name)
if obj.version != revlog.REVLOGV0:
if not self.revlogv1:
self.warn(_("warning: `%s' uses revlog format 1") % name)
elif self.revlogv1:
self.warn(_("warning: `%s' uses revlog format 0") % name)
def checkentry(self, obj, i, node, seen, linkrevs, f):
lr = obj.linkrev(obj.rev(node))
if lr < 0 or (self.havecl and lr not in linkrevs):
if lr < 0 or lr >= len(self.repo.changelog):
msg = _("rev %d points to nonexistent changeset %d")
else:
msg = _("rev %d points to unexpected changeset %d")
self.err(None, msg % (i, lr), f)
if linkrevs:
if f and len(linkrevs) > 1:
try:
# attempt to filter down to real linkrevs
linkrevs = [l for l in linkrevs
if self.lrugetctx(l)[f].filenode() == node]
except Exception:
pass
self.warn(_(" (expected %s)") % " ".join(map(str, linkrevs)))
lr = None # can't be trusted
try:
p1, p2 = obj.parents(node)
if p1 not in seen and p1 != nullid:
self.err(lr, _("unknown parent 1 %s of %s") %
(short(p1), short(node)), f)
if p2 not in seen and p2 != nullid:
self.err(lr, _("unknown parent 2 %s of %s") %
(short(p2), short(node)), f)
except Exception as inst:
self.exc(lr, _("checking parents of %s") % short(node), inst, f)
if node in seen:
self.err(lr, _("duplicate revision %d (%d)") % (i, seen[node]), f)
seen[node] = i
return lr
def verify(self):
repo = self.repo
ui = repo.ui
if not repo.url().startswith('file:'):
raise error.Abort(_("cannot verify bundle or remote repos"))
if os.path.exists(repo.sjoin("journal")):
ui.warn(_("abandoned transaction found - run hg recover\n"))
if ui.verbose or not self.revlogv1:
ui.status(_("repository uses revlog format %d\n") %
(self.revlogv1 and 1 or 0))
mflinkrevs, filelinkrevs = self._verifychangelog()
filenodes = self._verifymanifest(mflinkrevs)
del mflinkrevs
self._crosscheckfiles(filelinkrevs, filenodes)
totalfiles, filerevisions = self._verifyfiles(filenodes, filelinkrevs)
ui.status(_("%d files, %d changesets, %d total revisions\n") %
(totalfiles, len(repo.changelog), filerevisions))
if self.warnings:
ui.warn(_("%d warnings encountered!\n") % self.warnings)
if self.fncachewarned:
ui.warn(_('hint: run "hg debugrebuildfncache" to recover from '
'corrupt fncache\n'))
if self.errors:
ui.warn(_("%d integrity errors encountered!\n") % self.errors)
if self.badrevs:
ui.warn(_("(first damaged changeset appears to be %d)\n")
% min(self.badrevs))
return 1
def _verifychangelog(self):
ui = self.ui
repo = self.repo
cl = repo.changelog
ui.status(_("checking changesets\n"))
mflinkrevs = {}
filelinkrevs = {}
seen = {}
self.checklog(cl, "changelog", 0)
total = len(repo)
for i in repo:
ui.progress(_('checking'), i, total=total, unit=_('changesets'))
n = cl.node(i)
self.checkentry(cl, i, n, seen, [i], "changelog")
try:
changes = cl.read(n)
if changes[0] != nullid:
mflinkrevs.setdefault(changes[0], []).append(i)
self.refersmf = True
for f in changes[3]:
if _validpath(repo, f):
filelinkrevs.setdefault(_normpath(f), []).append(i)
except Exception as inst:
self.refersmf = True
self.exc(i, _("unpacking changeset %s") % short(n), inst)
ui.progress(_('checking'), None)
return mflinkrevs, filelinkrevs
def _verifymanifest(self, mflinkrevs, dir="", storefiles=None,
progress=None):
repo = self.repo
ui = self.ui
mfl = self.repo.manifestlog
mf = mfl._revlog.dirlog(dir)
if not dir:
self.ui.status(_("checking manifests\n"))
filenodes = {}
subdirnodes = {}
seen = {}
label = "manifest"
if dir:
label = dir
revlogfiles = mf.files()
storefiles.difference_update(revlogfiles)
if progress: # should be true since we're in a subdirectory
progress()
if self.refersmf:
# Do not check manifest if there are only changelog entries with
# null manifests.
self.checklog(mf, label, 0)
total = len(mf)
for i in mf:
if not dir:
ui.progress(_('checking'), i, total=total, unit=_('manifests'))
n = mf.node(i)
lr = self.checkentry(mf, i, n, seen, mflinkrevs.get(n, []), label)
if n in mflinkrevs:
del mflinkrevs[n]
elif dir:
self.err(lr, _("%s not in parent-directory manifest") %
short(n), label)
else:
self.err(lr, _("%s not in changesets") % short(n), label)
try:
mfdelta = mfl.get(dir, n).readdelta(shallow=True)
for f, fn, fl in mfdelta.iterentries():
if not f:
self.err(lr, _("entry without name in manifest"))
elif f == "/dev/null": # ignore this in very old repos
continue
fullpath = dir + _normpath(f)
if not _validpath(repo, fullpath):
continue
if fl == 't':
subdirnodes.setdefault(fullpath + '/', {}).setdefault(
fn, []).append(lr)
else:
filenodes.setdefault(fullpath, {}).setdefault(fn, lr)
except Exception as inst:
self.exc(lr, _("reading delta %s") % short(n), inst, label)
if not dir:
ui.progress(_('checking'), None)
if self.havemf:
for c, m in sorted([(c, m) for m in mflinkrevs
for c in mflinkrevs[m]]):
if dir:
self.err(c, _("parent-directory manifest refers to unknown "
"revision %s") % short(m), label)
else:
self.err(c, _("changeset refers to unknown revision %s") %
short(m), label)
if not dir and subdirnodes:
self.ui.status(_("checking directory manifests\n"))
storefiles = set()
subdirs = set()
revlogv1 = self.revlogv1
for f, f2, size in repo.store.datafiles():
if not f:
self.err(None, _("cannot decode filename '%s'") % f2)
elif (size > 0 or not revlogv1) and f.startswith('meta/'):
storefiles.add(_normpath(f))
subdirs.add(os.path.dirname(f))
subdircount = len(subdirs)
currentsubdir = [0]
def progress():
currentsubdir[0] += 1
ui.progress(_('checking'), currentsubdir[0], total=subdircount,
unit=_('manifests'))
for subdir, linkrevs in subdirnodes.iteritems():
subdirfilenodes = self._verifymanifest(linkrevs, subdir, storefiles,
progress)
for f, onefilenodes in subdirfilenodes.iteritems():
filenodes.setdefault(f, {}).update(onefilenodes)
if not dir and subdirnodes:
ui.progress(_('checking'), None)
for f in sorted(storefiles):
self.warn(_("warning: orphan revlog '%s'") % f)
return filenodes
def _crosscheckfiles(self, filelinkrevs, filenodes):
repo = self.repo
ui = self.ui
ui.status(_("crosschecking files in changesets and manifests\n"))
total = len(filelinkrevs) + len(filenodes)
count = 0
if self.havemf:
for f in sorted(filelinkrevs):
count += 1
ui.progress(_('crosschecking'), count, total=total)
if f not in filenodes:
lr = filelinkrevs[f][0]
self.err(lr, _("in changeset but not in manifest"), f)
if self.havecl:
for f in sorted(filenodes):
count += 1
ui.progress(_('crosschecking'), count, total=total)
if f not in filelinkrevs:
try:
fl = repo.file(f)
lr = min([fl.linkrev(fl.rev(n)) for n in filenodes[f]])
except Exception:
lr = None
self.err(lr, _("in manifest but not in changeset"), f)
ui.progress(_('crosschecking'), None)
def _verifyfiles(self, filenodes, filelinkrevs):
repo = self.repo
ui = self.ui
lrugetctx = self.lrugetctx
revlogv1 = self.revlogv1
havemf = self.havemf
ui.status(_("checking files\n"))
storefiles = set()
for f, f2, size in repo.store.datafiles():
if not f:
self.err(None, _("cannot decode filename '%s'") % f2)
elif (size > 0 or not revlogv1) and f.startswith('data/'):
storefiles.add(_normpath(f))
files = sorted(set(filenodes) | set(filelinkrevs))
total = len(files)
revisions = 0
for i, f in enumerate(files):
ui.progress(_('checking'), i, item=f, total=total, unit=_('files'))
try:
linkrevs = filelinkrevs[f]
except KeyError:
# in manifest but not in changelog
linkrevs = []
if linkrevs:
lr = linkrevs[0]
else:
lr = None
try:
fl = repo.file(f)
except error.RevlogError as e:
self.err(lr, _("broken revlog! (%s)") % e, f)
continue
for ff in fl.files():
try:
storefiles.remove(ff)
except KeyError:
self.warn(_(" warning: revlog '%s' not in fncache!") % ff)
self.fncachewarned = True
self.checklog(fl, f, lr)
seen = {}
rp = None
for i in fl:
revisions += 1
n = fl.node(i)
lr = self.checkentry(fl, i, n, seen, linkrevs, f)
if f in filenodes:
if havemf and n not in filenodes[f]:
self.err(lr, _("%s not in manifests") % (short(n)), f)
else:
del filenodes[f][n]
# verify contents
try:
l = len(fl.read(n))
rp = fl.renamed(n)
if l != fl.size(i):
if len(fl.revision(n)) != fl.size(i):
self.err(lr, _("unpacked size is %s, %s expected") %
(l, fl.size(i)), f)
except error.CensoredNodeError:
# experimental config: censor.policy
if ui.config("censor", "policy", "abort") == "abort":
self.err(lr, _("censored file data"), f)
except Exception as inst:
self.exc(lr, _("unpacking %s") % short(n), inst, f)
# check renames
try:
if rp:
if lr is not None and ui.verbose:
ctx = lrugetctx(lr)
found = False
for pctx in ctx.parents():
if rp[0] in pctx:
found = True
break
if not found:
self.warn(_("warning: copy source of '%s' not"
" in parents of %s") % (f, ctx))
fl2 = repo.file(rp[0])
if not len(fl2):
self.err(lr, _("empty or missing copy source "
"revlog %s:%s") % (rp[0], short(rp[1])), f)
elif rp[1] == nullid:
ui.note(_("warning: %s@%s: copy source"
" revision is nullid %s:%s\n")
% (f, lr, rp[0], short(rp[1])))
else:
fl2.rev(rp[1])
except Exception as inst:
self.exc(lr, _("checking rename of %s") % short(n), inst, f)
# cross-check
if f in filenodes:
fns = [(v, k) for k, v in filenodes[f].iteritems()]
for lr, node in sorted(fns):
self.err(lr, _("manifest refers to unknown revision %s") %
short(node), f)
ui.progress(_('checking'), None)
for f in sorted(storefiles):
self.warn(_("warning: orphan revlog '%s'") % f)
return len(files), revisions