Mercurial > hg
view hgext/logtoprocess.py @ 30446:b324b4e431e5
posix: give checkexec a fast path; keep the check files and test read only
Before, Mercurial would create a new temporary file every time, stat it, change
its exec mode, stat it again, and delete it. Most of this dance was done to
handle the rare and not-so-essential case of VFAT mounts on unix. The cost of
that was paid by the much more common and important case of using normal file
systems.
Instead, try to create and preserve .hg/cache/checkisexec and
.hg/cache/checknoexec with and without exec flag set. If the files exist and
have correct exec flags set, we can conclude that that file system supports the
exec flag. Best case, the whole exec check can thus be done with two stat
calls. Worst case, we delete the wrong files and check as usual. That will be
because temporary loss of exec bit or on file systems without support for the
exec bit. In that case we check as we did before, with the additional overhead
of one extra stat call.
It is possible that this different test algorithm in some cases on odd file
systems will give different behaviour. Again, I think it will be rare and
special cases and I think it is worth the risk.
test-clone.t happens to show the situation where checkisexec is left behind
from the old style check, while checknoexec only will be created next time a
exec check will be performed.
author | Mads Kiilerich <madski@unity3d.com> |
---|---|
date | Wed, 14 Jan 2015 01:15:26 +0100 |
parents | 318a24b52eeb |
children | 1c5cbf28f007 |
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# logtoprocess.py - send ui.log() data to a subprocess # # Copyright 2016 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. """Send ui.log() data to a subprocess (EXPERIMENTAL) This extension lets you specify a shell command per ui.log() event, sending all remaining arguments to as environment variables to that command. Each positional argument to the method results in a `MSG[N]` key in the environment, starting at 1 (so `MSG1`, `MSG2`, etc.). Each keyword argument is set as a `OPT_UPPERCASE_KEY` variable (so the key is uppercased, and prefixed with `OPT_`). The original event name is passed in the `EVENT` environment variable, and the process ID of mercurial is given in `HGPID`. So given a call `ui.log('foo', 'bar', 'baz', spam='eggs'), a script configured for the `foo` event can expect an environment with `MSG1=bar`, `MSG2=baz`, and `OPT_SPAM=eggs`. Scripts are configured in the `[logtoprocess]` section, each key an event name. For example:: [logtoprocess] commandexception = echo "$MSG2$MSG3" > /var/log/mercurial_exceptions.log would log the warning message and traceback of any failed command dispatch. Scripts are run asynchronously as detached daemon processes; mercurial will not ensure that they exit cleanly. """ from __future__ import absolute_import import itertools import os import platform import subprocess import sys # 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' def uisetup(ui): if platform.system() == 'Windows': # no fork on Windows, but we can create a detached process # https://msdn.microsoft.com/en-us/library/windows/desktop/ms684863.aspx # No stdlib constant exists for this value DETACHED_PROCESS = 0x00000008 _creationflags = DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP def runshellcommand(script, env): # we can't use close_fds *and* redirect stdin. I'm not sure that we # need to because the detached process has no console connection. subprocess.Popen( script, shell=True, env=env, close_fds=True, creationflags=_creationflags) else: def runshellcommand(script, env): # double-fork to completely detach from the parent process # based on http://code.activestate.com/recipes/278731 pid = os.fork() if pid: # parent return # subprocess.Popen() forks again, all we need to add is # flag the new process as a new session. if sys.version_info < (3, 2): newsession = {'preexec_fn': os.setsid} else: newsession = {'start_new_session': True} try: # connect stdin to devnull to make sure the subprocess can't # muck up that stream for mercurial. subprocess.Popen( script, shell=True, stdin=open(os.devnull, 'r'), env=env, close_fds=True, **newsession) finally: # mission accomplished, this child needs to exit and not # continue the hg process here. os._exit(0) class logtoprocessui(ui.__class__): def log(self, event, *msg, **opts): """Map log events to external commands Arguments are passed on as environment variables. """ script = self.config('logtoprocess', event) if script: if msg: # try to format the log message given the remaining # arguments try: # Python string formatting with % either uses a # dictionary *or* tuple, but not both. If we have # keyword options, assume we need a mapping. formatted = msg[0] % (opts or msg[1:]) except (TypeError, KeyError): # Failed to apply the arguments, ignore formatted = msg[0] messages = (formatted,) + msg[1:] else: messages = msg # positional arguments are listed as MSG[N] keys in the # environment msgpairs = ( ('MSG{0:d}'.format(i), str(m)) for i, m in enumerate(messages, 1)) # keyword arguments get prefixed with OPT_ and uppercased optpairs = ( ('OPT_{0}'.format(key.upper()), str(value)) for key, value in opts.iteritems()) env = dict(itertools.chain(os.environ.items(), msgpairs, optpairs), EVENT=event, HGPID=str(os.getpid())) # Connect stdin to /dev/null to prevent child processes messing # with mercurial's stdin. runshellcommand(script, env) return super(logtoprocessui, self).log(event, *msg, **opts) # Replace the class for this instance and all clones created from it: ui.__class__ = logtoprocessui