comparison mercurial/utils/procutil.py @ 42496:ca1014ad3de4

procutil: allow callers of runbgcommand to assume the process starts

Experimentally starting the subprocess can take as much as 40ms, and
for some of our use cases that's frivolous: we know the binary will
start, and if it doesn't we'd only ever ignore it and continue
anyway. This lets those use cases be faster.

Differential Revision: https://phab.mercurial-scm.org/D6537

42495:373aeede7352

    # Following creation flags might create a console GUI window.
    # Using subprocess.CREATE_NEW_CONSOLE might helps.
    # See https://phab.mercurial-scm.org/D1701 for discussion
    _creationflags = DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP

    def runbgcommand(script, env, shell=False, stdout=None, stderr=None):
        '''Spawn a command without waiting for it to finish.'''
        # 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(
            tonativestr(script),
            shell=shell, env=tonativeenv(env), close_fds=True,
            creationflags=_creationflags, stdout=stdout,
            stderr=stderr)
else:
    def runbgcommand(cmd, env, shell=False, stdout=None, stderr=None):
        '''Spawn a command without waiting for it to finish.'''
        # double-fork to completely detach from the parent process
        # based on http://code.activestate.com/recipes/278731
        pid = os.fork()
        if pid:
            # Parent process
            (_pid, status) = os.waitpid(pid, 0)
            if os.WIFEXITED(status):
                returncode = os.WEXITSTATUS(status)
            else:

42496:ca1014ad3de4

    # Following creation flags might create a console GUI window.
    # Using subprocess.CREATE_NEW_CONSOLE might helps.
    # See https://phab.mercurial-scm.org/D1701 for discussion
    _creationflags = DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP

    def runbgcommand(
      script, env, shell=False, stdout=None, stderr=None, ensurestart=True):
        '''Spawn a command without waiting for it to finish.'''
        # 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(
            tonativestr(script),
            shell=shell, env=tonativeenv(env), close_fds=True,
            creationflags=_creationflags, stdout=stdout,
            stderr=stderr)
else:
    def runbgcommand(
      cmd, env, shell=False, stdout=None, stderr=None, ensurestart=True):
        '''Spawn a command without waiting for it to finish.'''
        # double-fork to completely detach from the parent process
        # based on http://code.activestate.com/recipes/278731
        pid = os.fork()
        if pid:
            if not ensurestart:
                return
            # Parent process
            (_pid, status) = os.waitpid(pid, 0)
            if os.WIFEXITED(status):
                returncode = os.WEXITSTATUS(status)
            else: