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Differential D6537

procutil: allow callers of runbgcommand to assume the process starts
ClosedPublic

Authored by durin42 on Jun 18 2019, 9:44 AM.

Details

Reviewers
pulkit
Group Reviewers
hg-reviewers
Commits
rHGca1014ad3de4: procutil: allow callers of runbgcommand to assume the process starts
Summary

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.

Diff Detail

Repository
rHG Mercurial
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Automatic diff as part of commit; lint not applicable.
Unit
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Revision Contents
Changeset List

PathPackages
Mmercurial/utils/procutil.py (8 lines)

Diff 15577

mercurial/utils/procutil.py

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms684863.aspx # https://msdn.microsoft.com/en-us/library/windows/desktop/ms684863.aspx
# No stdlib constant exists for this value # No stdlib constant exists for this value
DETACHED_PROCESS = 0x00000008 DETACHED_PROCESS = 0x00000008
# Following creation flags might create a console GUI window. # Following creation flags might create a console GUI window.
# Using subprocess.CREATE_NEW_CONSOLE might helps. # Using subprocess.CREATE_NEW_CONSOLE might helps.
# See https://phab.mercurial-scm.org/D1701 for discussion # See https://phab.mercurial-scm.org/D1701 for discussion
_creationflags = DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP _creationflags = DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP
def runbgcommand(script, env, shell=False, stdout=None, stderr=None): def runbgcommand(
script, env, shell=False, stdout=None, stderr=None, ensurestart=True):
'''Spawn a command without waiting for it to finish.''' '''Spawn a command without waiting for it to finish.'''
# we can't use close_fds *and* redirect stdin. I'm not sure that we # 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. # need to because the detached process has no console connection.
subprocess.Popen( subprocess.Popen(
tonativestr(script), tonativestr(script),
shell=shell, env=tonativeenv(env), close_fds=True, shell=shell, env=tonativeenv(env), close_fds=True,
creationflags=_creationflags, stdout=stdout, creationflags=_creationflags, stdout=stdout,
stderr=stderr) stderr=stderr)
else: else:
def runbgcommand(cmd, env, shell=False, stdout=None, stderr=None): def runbgcommand(
cmd, env, shell=False, stdout=None, stderr=None, ensurestart=True):
'''Spawn a command without waiting for it to finish.''' '''Spawn a command without waiting for it to finish.'''
# double-fork to completely detach from the parent process # double-fork to completely detach from the parent process
# based on http://code.activestate.com/recipes/278731 # based on http://code.activestate.com/recipes/278731
pid = os.fork() pid = os.fork()
if pid: if pid:
if not ensurestart:
return
# Parent process # Parent process
(_pid, status) = os.waitpid(pid, 0) (_pid, status) = os.waitpid(pid, 0)
if os.WIFEXITED(status): if os.WIFEXITED(status):
returncode = os.WEXITSTATUS(status) returncode = os.WEXITSTATUS(status)
else: else:
returncode = -os.WTERMSIG(status) returncode = -os.WTERMSIG(status)
if returncode != 0: if returncode != 0:
# The child process's return code is 0 on success, an errno # The child process's return code is 0 on success, an errno