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import fcntl
import io
import os
from . import popen
from . import popen_fork
from . import reduction
from . import spawn
from . import util
from . import current_process
__all__ = ['Popen']
#
# Wrapper for an fd used while launching a process
#
class _DupFd(object):
def __init__(self, fd):
self.fd = fd
def detach(self):
return self.fd
#
# Start child process using a fresh interpreter
#
class Popen(popen_fork.Popen):
method = 'spawn'
DupFd = _DupFd
def __init__(self, process_obj):
self._fds = []
super().__init__(process_obj)
def duplicate_for_child(self, fd):
self._fds.append(fd)
return fd
def _launch(self, process_obj):
tracker_fd = current_process()._config['semaphore_tracker_fd']
self._fds.append(tracker_fd)
prep_data = spawn.get_preparation_data(process_obj._name)
fp = io.BytesIO()
popen.set_spawning_popen(self)
try:
reduction.dump(prep_data, fp)
reduction.dump(process_obj, fp)
finally:
popen.set_spawning_popen(None)
parent_r = child_w = child_r = parent_w = None
try:
parent_r, child_w = util.pipe()
child_r, parent_w = util.pipe()
cmd = spawn.get_command_line() + [str(child_r)]
self._fds.extend([child_r, child_w])
self.pid = util.spawnv_passfds(spawn.get_executable(),
cmd, self._fds)
self.sentinel = parent_r
with open(parent_w, 'wb', closefd=False) as f:
f.write(fp.getbuffer())
finally:
if parent_r is not None:
util.Finalize(self, os.close, (parent_r,))
for fd in (child_r, child_w, parent_w):
if fd is not None:
os.close(fd)
@staticmethod
def ensure_helpers_running():
from . import semaphore_tracker
semaphore_tracker.ensure_running()
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