lock: block signal interrupt while making a lock file
On Windows where symlink isn't supported, util.makelock() could leave an empty
file if interrupted immediately after os.open(). This empty lock never dies
as it has no process id recorded.
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
# an interrupt may occur here
os.write(ld, info)
os.close(ld)
This was a long-standing bug of TortoiseHg which runs a command-server and
kills it by CTRL_C_EVENT, reported by random Windows users.
https://bitbucket.org/tortoisehg/thg/issues/4873/#comment-
43591129
At first, I tried to fix makelock() to clean up a stale lock file, which
turned out to be hard because any instructions may be interrupted by a
signal.
ld = None
try:
# CALL_FUNCTION # os.open(...)
# an interrupt may occur here
# STORE_FAST # ld = ...
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
os.write(ld, info)
...
return True
except:
if ld:
...
os.unlink(pathname)
return False
So I decided to block signals by temporarily replacing the signal handlers
so makelcok() and held = 1 will never be interrupted.
Many thanks to Fernando Najera for investigating the issue.
# Copyright 2009, Alexander Solovyov <piranha@piranha.org.ua>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""extend schemes with shortcuts to repository swarms
This extension allows you to specify shortcuts for parent URLs with a
lot of repositories to act like a scheme, for example::
[schemes]
py = http://code.python.org/hg/
After that you can use it like::
hg clone py://trunk/
Additionally there is support for some more complex schemas, for
example used by Google Code::
[schemes]
gcode = http://{1}.googlecode.com/hg/
The syntax is taken from Mercurial templates, and you have unlimited
number of variables, starting with ``{1}`` and continuing with
``{2}``, ``{3}`` and so on. This variables will receive parts of URL
supplied, split by ``/``. Anything not specified as ``{part}`` will be
just appended to an URL.
For convenience, the extension adds these schemes by default::
[schemes]
py = http://hg.python.org/
bb = https://bitbucket.org/
bb+ssh = ssh://hg@bitbucket.org/
gcode = https://{1}.googlecode.com/hg/
kiln = https://{1}.kilnhg.com/Repo/
You can override a predefined scheme by defining a new scheme with the
same name.
"""
from __future__ import absolute_import
import os
import re
from mercurial.i18n import _
from mercurial import (
error,
extensions,
hg,
pycompat,
registrar,
templater,
util,
)
cmdtable = {}
command = registrar.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'
_partre = re.compile(br'\{(\d+)\}')
class ShortRepository(object):
def __init__(self, url, scheme, templater):
self.scheme = scheme
self.templater = templater
self.url = url
try:
self.parts = max(map(int, _partre.findall(self.url)))
except ValueError:
self.parts = 0
def __repr__(self):
return '<ShortRepository: %s>' % self.scheme
def instance(self, ui, url, create):
url = self.resolve(url)
return hg._peerlookup(url).instance(ui, url, create)
def resolve(self, url):
# Should this use the util.url class, or is manual parsing better?
try:
url = url.split('://', 1)[1]
except IndexError:
raise error.Abort(_("no '://' in scheme url '%s'") % url)
parts = url.split('/', self.parts)
if len(parts) > self.parts:
tail = parts[-1]
parts = parts[:-1]
else:
tail = ''
context = dict(('%d' % (i + 1), v) for i, v in enumerate(parts))
return ''.join(self.templater.process(self.url, context)) + tail
def hasdriveletter(orig, path):
if path:
for scheme in schemes:
if path.startswith(scheme + ':'):
return False
return orig(path)
schemes = {
'py': 'http://hg.python.org/',
'bb': 'https://bitbucket.org/',
'bb+ssh': 'ssh://hg@bitbucket.org/',
'gcode': 'https://{1}.googlecode.com/hg/',
'kiln': 'https://{1}.kilnhg.com/Repo/'
}
def extsetup(ui):
schemes.update(dict(ui.configitems('schemes')))
t = templater.engine(lambda x: x)
for scheme, url in schemes.items():
if (pycompat.iswindows and len(scheme) == 1 and scheme.isalpha()
and os.path.exists('%s:\\' % scheme)):
raise error.Abort(_('custom scheme %s:// conflicts with drive '
'letter %s:\\\n') % (scheme, scheme.upper()))
hg.schemes[scheme] = ShortRepository(url, scheme, t)
extensions.wrapfunction(util, 'hasdriveletter', hasdriveletter)
@command('debugexpandscheme', norepo=True)
def expandscheme(ui, url, **opts):
"""given a repo path, provide the scheme-expanded path
"""
repo = hg._peerlookup(url)
if isinstance(repo, ShortRepository):
url = repo.resolve(url)
ui.write(url + '\n')