/usr/lib/python3.7/multiprocessing/sharedctypes.py is in libpython3.7-stdlib 3.7.0~b3-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 | #
# Module which supports allocation of ctypes objects from shared memory
#
# multiprocessing/sharedctypes.py
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#
import ctypes
import weakref
from . import heap
from . import get_context
from .context import reduction, assert_spawning
_ForkingPickler = reduction.ForkingPickler
__all__ = ['RawValue', 'RawArray', 'Value', 'Array', 'copy', 'synchronized']
#
#
#
typecode_to_type = {
'c': ctypes.c_char, 'u': ctypes.c_wchar,
'b': ctypes.c_byte, 'B': ctypes.c_ubyte,
'h': ctypes.c_short, 'H': ctypes.c_ushort,
'i': ctypes.c_int, 'I': ctypes.c_uint,
'l': ctypes.c_long, 'L': ctypes.c_ulong,
'q': ctypes.c_longlong, 'Q': ctypes.c_ulonglong,
'f': ctypes.c_float, 'd': ctypes.c_double
}
#
#
#
def _new_value(type_):
size = ctypes.sizeof(type_)
wrapper = heap.BufferWrapper(size)
return rebuild_ctype(type_, wrapper, None)
def RawValue(typecode_or_type, *args):
'''
Returns a ctypes object allocated from shared memory
'''
type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
obj = _new_value(type_)
ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
obj.__init__(*args)
return obj
def RawArray(typecode_or_type, size_or_initializer):
'''
Returns a ctypes array allocated from shared memory
'''
type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
if isinstance(size_or_initializer, int):
type_ = type_ * size_or_initializer
obj = _new_value(type_)
ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
return obj
else:
type_ = type_ * len(size_or_initializer)
result = _new_value(type_)
result.__init__(*size_or_initializer)
return result
def Value(typecode_or_type, *args, lock=True, ctx=None):
'''
Return a synchronization wrapper for a Value
'''
obj = RawValue(typecode_or_type, *args)
if lock is False:
return obj
if lock in (True, None):
ctx = ctx or get_context()
lock = ctx.RLock()
if not hasattr(lock, 'acquire'):
raise AttributeError("%r has no method 'acquire'" % lock)
return synchronized(obj, lock, ctx=ctx)
def Array(typecode_or_type, size_or_initializer, *, lock=True, ctx=None):
'''
Return a synchronization wrapper for a RawArray
'''
obj = RawArray(typecode_or_type, size_or_initializer)
if lock is False:
return obj
if lock in (True, None):
ctx = ctx or get_context()
lock = ctx.RLock()
if not hasattr(lock, 'acquire'):
raise AttributeError("%r has no method 'acquire'" % lock)
return synchronized(obj, lock, ctx=ctx)
def copy(obj):
new_obj = _new_value(type(obj))
ctypes.pointer(new_obj)[0] = obj
return new_obj
def synchronized(obj, lock=None, ctx=None):
assert not isinstance(obj, SynchronizedBase), 'object already synchronized'
ctx = ctx or get_context()
if isinstance(obj, ctypes._SimpleCData):
return Synchronized(obj, lock, ctx)
elif isinstance(obj, ctypes.Array):
if obj._type_ is ctypes.c_char:
return SynchronizedString(obj, lock, ctx)
return SynchronizedArray(obj, lock, ctx)
else:
cls = type(obj)
try:
scls = class_cache[cls]
except KeyError:
names = [field[0] for field in cls._fields_]
d = {name: make_property(name) for name in names}
classname = 'Synchronized' + cls.__name__
scls = class_cache[cls] = type(classname, (SynchronizedBase,), d)
return scls(obj, lock, ctx)
#
# Functions for pickling/unpickling
#
def reduce_ctype(obj):
assert_spawning(obj)
if isinstance(obj, ctypes.Array):
return rebuild_ctype, (obj._type_, obj._wrapper, obj._length_)
else:
return rebuild_ctype, (type(obj), obj._wrapper, None)
def rebuild_ctype(type_, wrapper, length):
if length is not None:
type_ = type_ * length
_ForkingPickler.register(type_, reduce_ctype)
buf = wrapper.create_memoryview()
obj = type_.from_buffer(buf)
obj._wrapper = wrapper
return obj
#
# Function to create properties
#
def make_property(name):
try:
return prop_cache[name]
except KeyError:
d = {}
exec(template % ((name,)*7), d)
prop_cache[name] = d[name]
return d[name]
template = '''
def get%s(self):
self.acquire()
try:
return self._obj.%s
finally:
self.release()
def set%s(self, value):
self.acquire()
try:
self._obj.%s = value
finally:
self.release()
%s = property(get%s, set%s)
'''
prop_cache = {}
class_cache = weakref.WeakKeyDictionary()
#
# Synchronized wrappers
#
class SynchronizedBase(object):
def __init__(self, obj, lock=None, ctx=None):
self._obj = obj
if lock:
self._lock = lock
else:
ctx = ctx or get_context(force=True)
self._lock = ctx.RLock()
self.acquire = self._lock.acquire
self.release = self._lock.release
def __enter__(self):
return self._lock.__enter__()
def __exit__(self, *args):
return self._lock.__exit__(*args)
def __reduce__(self):
assert_spawning(self)
return synchronized, (self._obj, self._lock)
def get_obj(self):
return self._obj
def get_lock(self):
return self._lock
def __repr__(self):
return '<%s wrapper for %s>' % (type(self).__name__, self._obj)
class Synchronized(SynchronizedBase):
value = make_property('value')
class SynchronizedArray(SynchronizedBase):
def __len__(self):
return len(self._obj)
def __getitem__(self, i):
with self:
return self._obj[i]
def __setitem__(self, i, value):
with self:
self._obj[i] = value
def __getslice__(self, start, stop):
with self:
return self._obj[start:stop]
def __setslice__(self, start, stop, values):
with self:
self._obj[start:stop] = values
class SynchronizedString(SynchronizedArray):
value = make_property('value')
raw = make_property('raw')
|