scmutil: add file object wrapper class to check ambiguity at closing
In Mercurial source tree, opening a file in "a"/"a+" mode like below
doesn't specify atomictemp=True for vfs, and this avoids file stat
ambiguity check by atomictempfile.
- writing changes out in revlog layer uses "a+" mode
- truncation in repair.strip() uses "a" mode
- truncation in transaction._playback() uses "a" mode
If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).
1. append data to revlog-style file (and close transaction)
2. discard appended data by truncation (strip or rollback)
3. append same size but different data to revlog-style file again
Therefore, cache validation doesn't work after (3) as expected.
This patch adds file object wrapper class checkambigatclosing to check
(and get rid of) ambiguity at closing. It is used by vfs in subsequent
patch.
This is a part of ExactCacheValidationPlan.
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
BTW, checkambigatclosing is tested in test-filecache.py, even though
it doesn't use filecache itself, because filecache assumes that file
stat ambiguity never occurs (and there is no another test-*.py related
to filecache).
# 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 (
cmdutil,
ui as uimod,
util,
)
cmdtable = {}
command = cmdutil.command(cmdtable)
# 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'
lastui = None
filehandles = {}
def _openlog(vfs):
path = vfs.join('blackbox.log')
if path in filehandles:
return filehandles[path]
filehandles[path] = fp = vfs('blackbox.log', 'a')
return fp
def _closelog(vfs):
path = vfs.join('blackbox.log')
fp = filehandles[path]
del filehandles[path]
fp.close()
def wrapui(ui):
class blackboxui(ui.__class__):
def __init__(self, src=None):
super(blackboxui, self).__init__(src)
if src is None:
self._partialinit()
else:
self._bbfp = getattr(src, '_bbfp', None)
self._bbinlog = False
self._bbrepo = getattr(src, '_bbrepo', None)
self._bbvfs = getattr(src, '_bbvfs', None)
def _partialinit(self):
if util.safehasattr(self, '_bbvfs'):
return
self._bbfp = None
self._bbinlog = False
self._bbrepo = None
self._bbvfs = None
def copy(self):
self._partialinit()
return self.__class__(self)
@util.propertycache
def track(self):
return self.configlist('blackbox', 'track', ['*'])
def _openlogfile(self):
def rotate(oldpath, newpath):
try:
self._bbvfs.unlink(newpath)
except OSError as err:
if err.errno != errno.ENOENT:
self.debug("warning: cannot remove '%s': %s\n" %
(newpath, err.strerror))
try:
if newpath:
self._bbvfs.rename(oldpath, newpath)
except OSError as err:
if err.errno != errno.ENOENT:
self.debug("warning: cannot rename '%s' to '%s': %s\n" %
(newpath, oldpath, err.strerror))
fp = _openlog(self._bbvfs)
maxsize = self.configbytes('blackbox', 'maxsize', 1048576)
if maxsize > 0:
st = self._bbvfs.fstat(fp)
if st.st_size >= maxsize:
path = fp.name
_closelog(self._bbvfs)
maxfiles = self.configint('blackbox', 'maxfiles', 7)
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')
fp = _openlog(self._bbvfs)
return fp
def _bbwrite(self, fmt, *args):
self._bbfp.write(fmt % args)
self._bbfp.flush()
def log(self, event, *msg, **opts):
global lastui
super(blackboxui, self).log(event, *msg, **opts)
self._partialinit()
if not '*' in self.track and not event in self.track:
return
if self._bbfp:
ui = self
elif self._bbvfs:
try:
self._bbfp = self._openlogfile()
except (IOError, OSError) as err:
self.debug('warning: cannot write to blackbox.log: %s\n' %
err.strerror)
del self._bbvfs
self._bbfp = None
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 or not ui._bbfp:
return
if not lastui or ui._bbrepo:
lastui = ui
if ui._bbinlog:
# recursion guard
return
try:
ui._bbinlog = True
date = util.datestr(None, '%Y/%m/%d %H:%M:%S')
user = util.getuser()
pid = str(util.getpid())
formattedmsg = msg[0] % msg[1:]
rev = '(unknown)'
changed = ''
if ui._bbrepo:
ctx = ui._bbrepo[None]
parents = ctx.parents()
rev = ('+'.join([hex(p.node()) for p in parents]))
if (ui.configbool('blackbox', 'dirty', False) and (
any(ui._bbrepo.status()) or
any(ctx.sub(s).dirty() for s in ctx.substate)
)):
changed = '+'
if ui.configbool('blackbox', 'logsource', False):
src = ' [%s]' % event
else:
src = ''
try:
ui._bbwrite('%s %s @%s%s (%s)%s> %s',
date, user, rev, changed, pid, src, formattedmsg)
except IOError as err:
self.debug('warning: cannot write to blackbox.log: %s\n' %
err.strerror)
finally:
ui._bbinlog = False
def setrepo(self, repo):
self._bbfp = None
self._bbinlog = False
self._bbrepo = repo
self._bbvfs = repo.vfs
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)
@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)))