79 lines
1.8 KiB
Python
79 lines
1.8 KiB
Python
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import sys
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import threading
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__all__ = ['Popen', 'get_spawning_popen', 'set_spawning_popen',
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'assert_spawning']
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#
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# Check that the current thread is spawning a child process
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#
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_tls = threading.local()
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def get_spawning_popen():
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return getattr(_tls, 'spawning_popen', None)
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def set_spawning_popen(popen):
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_tls.spawning_popen = popen
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def assert_spawning(obj):
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if get_spawning_popen() is None:
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raise RuntimeError(
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'%s objects should only be shared between processes'
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' through inheritance' % type(obj).__name__
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)
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#
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#
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#
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_Popen = None
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def Popen(process_obj):
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if _Popen is None:
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set_start_method()
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return _Popen(process_obj)
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def get_start_method():
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if _Popen is None:
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set_start_method()
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return _Popen.method
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def set_start_method(meth=None, *, start_helpers=True):
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global _Popen
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try:
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modname = _method_to_module[meth]
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__import__(modname)
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except (KeyError, ImportError):
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raise ValueError('could not use start method %r' % meth)
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module = sys.modules[modname]
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if start_helpers:
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module.Popen.ensure_helpers_running()
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_Popen = module.Popen
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if sys.platform == 'win32':
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_method_to_module = {
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None: 'multiprocessing.popen_spawn_win32',
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'spawn': 'multiprocessing.popen_spawn_win32',
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}
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def get_all_start_methods():
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return ['spawn']
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else:
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_method_to_module = {
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None: 'multiprocessing.popen_fork',
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'fork': 'multiprocessing.popen_fork',
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'spawn': 'multiprocessing.popen_spawn_posix',
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'forkserver': 'multiprocessing.popen_forkserver',
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}
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def get_all_start_methods():
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from . import reduction
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if reduction.HAVE_SEND_HANDLE:
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return ['fork', 'spawn', 'forkserver']
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else:
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return ['fork', 'spawn']
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