1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
import sys
import threading
__all__ = ['Popen', 'get_spawning_popen', 'set_spawning_popen',
'assert_spawning']
#
# Check that the current thread is spawning a child process
#
_tls = threading.local()
def get_spawning_popen():
return getattr(_tls, 'spawning_popen', None)
def set_spawning_popen(popen):
_tls.spawning_popen = popen
def assert_spawning(obj):
if get_spawning_popen() is None:
raise RuntimeError(
'%s objects should only be shared between processes'
' through inheritance' % type(obj).__name__
)
#
#
#
_Popen = None
def Popen(process_obj):
if _Popen is None:
set_start_method()
return _Popen(process_obj)
def get_start_method():
if _Popen is None:
set_start_method()
return _Popen.method
def set_start_method(meth=None, *, start_helpers=True):
global _Popen
try:
modname = _method_to_module[meth]
__import__(modname)
except (KeyError, ImportError):
raise ValueError('could not use start method %r' % meth)
module = sys.modules[modname]
if start_helpers:
module.Popen.ensure_helpers_running()
_Popen = module.Popen
if sys.platform == 'win32':
_method_to_module = {
None: 'multiprocessing.popen_spawn_win32',
'spawn': 'multiprocessing.popen_spawn_win32',
}
def get_all_start_methods():
return ['spawn']
else:
_method_to_module = {
None: 'multiprocessing.popen_fork',
'fork': 'multiprocessing.popen_fork',
'spawn': 'multiprocessing.popen_spawn_posix',
'forkserver': 'multiprocessing.popen_forkserver',
}
def get_all_start_methods():
from . import reduction
if reduction.HAVE_SEND_HANDLE:
return ['fork', 'spawn', 'forkserver']
else:
return ['fork', 'spawn']
|
