revlog: ignore empty trailing chunks when reading segments
When a merge commit creates an empty diff in the revlog, its offset may still
be quite far from the end of the previous chunk.
Skipping these empty chunks may reduce read size significantly.
In most cases, there is no gain, and in some cases, little gain.
On my clone of pypy, `hg manifest` reads 65% less bytes (96140 i/o 275943) for
revision 4260 by ignoring the only empty trailing diff.
For revision 2229, 35% (34557 i/o 53435)
Sadly, this is difficult to reproduce, as hg clone can make its own different
structure every time.
# blackbox.py - log repository events to a file for post-mortem debugging
#
# Copyright 2010 Nicolas Dumazet
# Copyright 2013 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""log repository events to a blackbox for debugging
Logs event information to .hg/blackbox.log to help debug and diagnose problems.
The events that get logged can be configured via the blackbox.track config key.
Examples::
[blackbox]
track = *
# dirty is *EXPENSIVE* (slow);
# each log entry indicates `+` if the repository is dirty, like :hg:`id`.
dirty = True
# record the source of log messages
logsource = True
[blackbox]
track = command, commandfinish, commandexception, exthook, pythonhook
[blackbox]
track = incoming
[blackbox]
# limit the size of a log file
maxsize = 1.5 MB
# rotate up to N log files when the current one gets too big
maxfiles = 3
"""
from __future__ import absolute_import
import errno
import re
from mercurial.i18n import _
from mercurial.node import hex
from mercurial import (
registrar,
ui as uimod,
util,
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' 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 = 'ships-with-hg-core'
cmdtable = {}
command = registrar.command(cmdtable)
configtable = {}
configitem = registrar.configitem(configtable)
configitem('blackbox', 'dirty',
default=False,
)
configitem('blackbox', 'maxsize',
default='1 MB',
)
configitem('blackbox', 'logsource',
default=False,
)
configitem('blackbox', 'maxfiles',
default=7,
)
configitem('blackbox', 'track',
default=lambda: ['*'],
)
lastui = None
def _openlogfile(ui, vfs):
def rotate(oldpath, newpath):
try:
vfs.unlink(newpath)
except OSError as err:
if err.errno != errno.ENOENT:
ui.debug("warning: cannot remove '%s': %s\n" %
(newpath, err.strerror))
try:
if newpath:
vfs.rename(oldpath, newpath)
except OSError as err:
if err.errno != errno.ENOENT:
ui.debug("warning: cannot rename '%s' to '%s': %s\n" %
(newpath, oldpath, err.strerror))
maxsize = ui.configbytes('blackbox', 'maxsize')
name = 'blackbox.log'
if maxsize > 0:
try:
st = vfs.stat(name)
except OSError:
pass
else:
if st.st_size >= maxsize:
path = vfs.join(name)
maxfiles = ui.configint('blackbox', 'maxfiles')
for i in xrange(maxfiles - 1, 1, -1):
rotate(oldpath='%s.%d' % (path, i - 1),
newpath='%s.%d' % (path, i))
rotate(oldpath=path,
newpath=maxfiles > 0 and path + '.1')
return vfs(name, 'a')
def wrapui(ui):
class blackboxui(ui.__class__):
@property
def _bbvfs(self):
vfs = None
repo = getattr(self, '_bbrepo', None)
if repo:
vfs = repo.vfs
if not vfs.isdir('.'):
vfs = None
return vfs
@util.propertycache
def track(self):
return self.configlist('blackbox', 'track')
def log(self, event, *msg, **opts):
global lastui
super(blackboxui, self).log(event, *msg, **opts)
if not '*' in self.track and not event in self.track:
return
if self._bbvfs:
ui = self
else:
# certain ui instances exist outside the context of
# a repo, so just default to the last blackbox that
# was seen.
ui = lastui
if not ui:
return
vfs = ui._bbvfs
if not vfs:
return
repo = getattr(ui, '_bbrepo', None)
if not lastui or repo:
lastui = ui
if getattr(ui, '_bbinlog', False):
# recursion and failure guard
return
ui._bbinlog = True
default = self.configdate('devel', 'default-date')
date = util.datestr(default, '%Y/%m/%d %H:%M:%S')
user = util.getuser()
pid = '%d' % util.getpid()
formattedmsg = msg[0] % msg[1:]
rev = '(unknown)'
changed = ''
if repo:
ctx = repo[None]
parents = ctx.parents()
rev = ('+'.join([hex(p.node()) for p in parents]))
if (ui.configbool('blackbox', 'dirty') and
ctx.dirty(missing=True, merge=False, branch=False)):
changed = '+'
if ui.configbool('blackbox', 'logsource'):
src = ' [%s]' % event
else:
src = ''
try:
fmt = '%s %s @%s%s (%s)%s> %s'
args = (date, user, rev, changed, pid, src, formattedmsg)
with _openlogfile(ui, vfs) as fp:
fp.write(fmt % args)
except (IOError, OSError) as err:
self.debug('warning: cannot write to blackbox.log: %s\n' %
err.strerror)
# do not restore _bbinlog intentionally to avoid failed
# logging again
else:
ui._bbinlog = False
def setrepo(self, repo):
self._bbrepo = repo
ui.__class__ = blackboxui
uimod.ui = blackboxui
def uisetup(ui):
wrapui(ui)
def reposetup(ui, repo):
# During 'hg pull' a httppeer repo is created to represent the remote repo.
# It doesn't have a .hg directory to put a blackbox in, so we don't do
# the blackbox setup for it.
if not repo.local():
return
if util.safehasattr(ui, 'setrepo'):
ui.setrepo(repo)
# Set lastui even if ui.log is not called. This gives blackbox a
# fallback place to log.
global lastui
if lastui is None:
lastui = ui
repo._wlockfreeprefix.add('blackbox.log')
@command('^blackbox',
[('l', 'limit', 10, _('the number of events to show')),
],
_('hg blackbox [OPTION]...'))
def blackbox(ui, repo, *revs, **opts):
'''view the recent repository events
'''
if not repo.vfs.exists('blackbox.log'):
return
limit = opts.get('limit')
fp = repo.vfs('blackbox.log', 'r')
lines = fp.read().split('\n')
count = 0
output = []
for line in reversed(lines):
if count >= limit:
break
# count the commands by matching lines like: 2013/01/23 19:13:36 root>
if re.match('^\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2} .*> .*', line):
count += 1
output.append(line)
ui.status('\n'.join(reversed(output)))