bisect: avoid copying ancestor list for non-merge commits
During a bisection, hg needs to compute a list of all ancestors for every
candidate commit. This is accomplished via a bottom-up traversal of the set of
candidates, during which each revision's ancestor list is populated using the
ancestor list of its parent(s). Previously, this involved copying the entire
list, which could be very long in if the bisection range was large.
To help improve this, we can observe that each candidate commit is visited
exactly once, at which point its ancestor list is copied into its children's
lists and then dropped. In the case of non-merge commits, a commit's ancestor
list consists exactly of its parent's list plus itself. This means that we can
trivially reuse the parent's existing list for one of its non-merge children,
which avoids copying entirely if that commit is the parent's only child. This
makes bisections over linear ranges of commits much faster.
During some informal testing in the large publicly-available `mozilla-central`
repository, this noticeably sped up bisections over large ranges of history:
Setup:
$ cd mozilla-central
$ hg bisect --reset
$ hg bisect --good 0
$ hg log -r tip -T '{rev}\n'
628417
Test:
$ time hg bisect --bad tip --noupdate
Before:
real 3m35.927s
user 3m35.553s
sys 0m0.319s
After:
real 1m41.142s
user 1m40.810s
sys 0m0.285s
# server.py - utility and factory of server
#
# Copyright 2005-2007 Olivia Mackall <olivia@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.
import os
from .i18n import _
from .pycompat import open
from . import (
chgserver,
cmdutil,
commandserver,
error,
hgweb,
pycompat,
util,
)
from .utils import (
procutil,
urlutil,
)
def runservice(
opts,
parentfn=None,
initfn=None,
runfn=None,
logfile=None,
runargs=None,
appendpid=False,
):
'''Run a command as a service.'''
postexecargs = {}
if opts[b'daemon_postexec']:
for inst in opts[b'daemon_postexec']:
if inst.startswith(b'unlink:'):
postexecargs[b'unlink'] = inst[7:]
elif inst.startswith(b'chdir:'):
postexecargs[b'chdir'] = inst[6:]
elif inst != b'none':
raise error.Abort(
_(b'invalid value for --daemon-postexec: %s') % inst
)
# When daemonized on Windows, redirect stdout/stderr to the lockfile (which
# gets cleaned up after the child is up and running), so that the parent can
# read and print the error if this child dies early. See 594dd384803c. On
# other platforms, the child can write to the parent's stdio directly, until
# it is redirected prior to runfn().
if pycompat.iswindows and opts[b'daemon_postexec']:
if b'unlink' in postexecargs and os.path.exists(
postexecargs[b'unlink']
):
procutil.stdout.flush()
procutil.stderr.flush()
fd = os.open(
postexecargs[b'unlink'], os.O_WRONLY | os.O_APPEND | os.O_BINARY
)
try:
os.dup2(fd, procutil.stdout.fileno())
os.dup2(fd, procutil.stderr.fileno())
finally:
os.close(fd)
def writepid(pid):
if opts[b'pid_file']:
if appendpid:
mode = b'ab'
else:
mode = b'wb'
fp = open(opts[b'pid_file'], mode)
fp.write(b'%d\n' % pid)
fp.close()
if opts[b'daemon'] and not opts[b'daemon_postexec']:
# Signal child process startup with file removal
lockfd, lockpath = pycompat.mkstemp(prefix=b'hg-service-')
os.close(lockfd)
try:
if not runargs:
runargs = procutil.hgcmd() + pycompat.sysargv[1:]
runargs.append(b'--daemon-postexec=unlink:%s' % lockpath)
# Don't pass --cwd to the child process, because we've already
# changed directory.
for i in range(1, len(runargs)):
if runargs[i].startswith(b'--cwd='):
del runargs[i]
break
elif runargs[i].startswith(b'--cwd'):
del runargs[i : i + 2]
break
def condfn():
return not os.path.exists(lockpath)
pid = procutil.rundetached(runargs, condfn)
if pid < 0:
# If the daemonized process managed to write out an error msg,
# report it.
if pycompat.iswindows and os.path.exists(lockpath):
with open(lockpath, b'rb') as log:
for line in log:
procutil.stderr.write(line)
raise error.Abort(_(b'child process failed to start'))
writepid(pid)
finally:
util.tryunlink(lockpath)
if parentfn:
return parentfn(pid)
else:
return
if initfn:
initfn()
if not opts[b'daemon']:
writepid(procutil.getpid())
if opts[b'daemon_postexec']:
try:
os.setsid()
except AttributeError:
pass
if b'chdir' in postexecargs:
os.chdir(postexecargs[b'chdir'])
procutil.hidewindow()
procutil.stdout.flush()
procutil.stderr.flush()
nullfd = os.open(os.devnull, os.O_RDWR)
logfilefd = nullfd
if logfile:
logfilefd = os.open(
logfile, os.O_RDWR | os.O_CREAT | os.O_APPEND, 0o666
)
os.dup2(nullfd, procutil.stdin.fileno())
os.dup2(logfilefd, procutil.stdout.fileno())
os.dup2(logfilefd, procutil.stderr.fileno())
stdio = (
procutil.stdin.fileno(),
procutil.stdout.fileno(),
procutil.stderr.fileno(),
)
if nullfd not in stdio:
os.close(nullfd)
if logfile and logfilefd not in stdio:
os.close(logfilefd)
# Only unlink after redirecting stdout/stderr, so Windows doesn't
# complain about a sharing violation.
if b'unlink' in postexecargs:
os.unlink(postexecargs[b'unlink'])
if runfn:
return runfn()
_cmdservicemap = {
b'chgunix': chgserver.chgunixservice,
b'pipe': commandserver.pipeservice,
b'unix': commandserver.unixforkingservice,
}
def _createcmdservice(ui, repo, opts):
mode = opts[b'cmdserver']
try:
servicefn = _cmdservicemap[mode]
except KeyError:
raise error.Abort(_(b'unknown mode %s') % mode)
commandserver.setuplogging(ui, repo)
return servicefn(ui, repo, opts)
def _createhgwebservice(ui, repo, opts):
# this way we can check if something was given in the command-line
if opts.get(b'port'):
opts[b'port'] = urlutil.getport(opts.get(b'port'))
alluis = {ui}
if repo:
baseui = repo.baseui
alluis.update([repo.baseui, repo.ui])
else:
baseui = ui
webconf = opts.get(b'web_conf') or opts.get(b'webdir_conf')
if webconf:
if opts.get(b'subrepos'):
raise error.Abort(_(b'--web-conf cannot be used with --subrepos'))
# load server settings (e.g. web.port) to "copied" ui, which allows
# hgwebdir to reload webconf cleanly
servui = ui.copy()
servui.readconfig(webconf, sections=[b'web'])
alluis.add(servui)
elif opts.get(b'subrepos'):
servui = ui
# If repo is None, hgweb.createapp() already raises a proper abort
# message as long as webconf is None.
if repo:
webconf = dict()
cmdutil.addwebdirpath(repo, b"", webconf)
else:
servui = ui
optlist = (
b"name templates style address port prefix ipv6"
b" accesslog errorlog certificate encoding"
)
for o in optlist.split():
val = opts.get(o, b'')
if val in (None, b''): # should check against default options instead
continue
for u in alluis:
u.setconfig(b"web", o, val, b'serve')
app = hgweb.createapp(baseui, repo, webconf)
return hgweb.httpservice(servui, app, opts)
def createservice(ui, repo, opts):
if opts[b"cmdserver"]:
return _createcmdservice(ui, repo, opts)
else:
return _createhgwebservice(ui, repo, opts)