Python code coverage for Lib/multiprocessing/sharedctypes.py

#	count	content
1	n/a	#
2	n/a	# Module which supports allocation of ctypes objects from shared memory
3	n/a	#
4	n/a	# multiprocessing/sharedctypes.py
5	n/a	#
6	n/a	# Copyright (c) 2006-2008, R Oudkerk
7	n/a	# Licensed to PSF under a Contributor Agreement.
8	n/a	#
9	n/a
10	n/a	import ctypes
11	n/a	import weakref
12	n/a
13	n/a	from . import heap
14	n/a	from . import get_context
15	n/a
16	n/a	from .context import reduction, assert_spawning
17	n/a	_ForkingPickler = reduction.ForkingPickler
18	n/a
19	n/a	__all__ = ['RawValue', 'RawArray', 'Value', 'Array', 'copy', 'synchronized']
20	n/a
21	n/a	#
22	n/a	#
23	n/a	#
24	n/a
25	n/a	typecode_to_type = {
26	n/a	'c': ctypes.c_char, 'u': ctypes.c_wchar,
27	n/a	'b': ctypes.c_byte, 'B': ctypes.c_ubyte,
28	n/a	'h': ctypes.c_short, 'H': ctypes.c_ushort,
29	n/a	'i': ctypes.c_int, 'I': ctypes.c_uint,
30	n/a	'l': ctypes.c_long, 'L': ctypes.c_ulong,
31	n/a	'f': ctypes.c_float, 'd': ctypes.c_double
32	n/a	}
33	n/a
34	n/a	#
35	n/a	#
36	n/a	#
37	n/a
38	n/a	def _new_value(type_):
39	n/a	size = ctypes.sizeof(type_)
40	n/a	wrapper = heap.BufferWrapper(size)
41	n/a	return rebuild_ctype(type_, wrapper, None)
42	n/a
43	n/a	def RawValue(typecode_or_type, *args):
44	n/a	'''
45	n/a	Returns a ctypes object allocated from shared memory
46	n/a	'''
47	n/a	type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
48	n/a	obj = _new_value(type_)
49	n/a	ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
50	n/a	obj.__init__(*args)
51	n/a	return obj
52	n/a
53	n/a	def RawArray(typecode_or_type, size_or_initializer):
54	n/a	'''
55	n/a	Returns a ctypes array allocated from shared memory
56	n/a	'''
57	n/a	type_ = typecode_to_type.get(typecode_or_type, typecode_or_type)
58	n/a	if isinstance(size_or_initializer, int):
59	n/a	type_ = type_ * size_or_initializer
60	n/a	obj = _new_value(type_)
61	n/a	ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj))
62	n/a	return obj
63	n/a	else:
64	n/a	type_ = type_ * len(size_or_initializer)
65	n/a	result = _new_value(type_)
66	n/a	result.__init__(*size_or_initializer)
67	n/a	return result
68	n/a
69	n/a	def Value(typecode_or_type, *args, lock=True, ctx=None):
70	n/a	'''
71	n/a	Return a synchronization wrapper for a Value
72	n/a	'''
73	n/a	obj = RawValue(typecode_or_type, *args)
74	n/a	if lock is False:
75	n/a	return obj
76	n/a	if lock in (True, None):
77	n/a	ctx = ctx or get_context()
78	n/a	lock = ctx.RLock()
79	n/a	if not hasattr(lock, 'acquire'):
80	n/a	raise AttributeError("'%r' has no method 'acquire'" % lock)
81	n/a	return synchronized(obj, lock, ctx=ctx)
82	n/a
83	n/a	def Array(typecode_or_type, size_or_initializer, *, lock=True, ctx=None):
84	n/a	'''
85	n/a	Return a synchronization wrapper for a RawArray
86	n/a	'''
87	n/a	obj = RawArray(typecode_or_type, size_or_initializer)
88	n/a	if lock is False:
89	n/a	return obj
90	n/a	if lock in (True, None):
91	n/a	ctx = ctx or get_context()
92	n/a	lock = ctx.RLock()
93	n/a	if not hasattr(lock, 'acquire'):
94	n/a	raise AttributeError("'%r' has no method 'acquire'" % lock)
95	n/a	return synchronized(obj, lock, ctx=ctx)
96	n/a
97	n/a	def copy(obj):
98	n/a	new_obj = _new_value(type(obj))
99	n/a	ctypes.pointer(new_obj)[0] = obj
100	n/a	return new_obj
101	n/a
102	n/a	def synchronized(obj, lock=None, ctx=None):
103	n/a	assert not isinstance(obj, SynchronizedBase), 'object already synchronized'
104	n/a	ctx = ctx or get_context()
105	n/a
106	n/a	if isinstance(obj, ctypes._SimpleCData):
107	n/a	return Synchronized(obj, lock, ctx)
108	n/a	elif isinstance(obj, ctypes.Array):
109	n/a	if obj._type_ is ctypes.c_char:
110	n/a	return SynchronizedString(obj, lock, ctx)
111	n/a	return SynchronizedArray(obj, lock, ctx)
112	n/a	else:
113	n/a	cls = type(obj)
114	n/a	try:
115	n/a	scls = class_cache[cls]
116	n/a	except KeyError:
117	n/a	names = [field[0] for field in cls._fields_]
118	n/a	d = dict((name, make_property(name)) for name in names)
119	n/a	classname = 'Synchronized' + cls.__name__
120	n/a	scls = class_cache[cls] = type(classname, (SynchronizedBase,), d)
121	n/a	return scls(obj, lock, ctx)
122	n/a
123	n/a	#
124	n/a	# Functions for pickling/unpickling
125	n/a	#
126	n/a
127	n/a	def reduce_ctype(obj):
128	n/a	assert_spawning(obj)
129	n/a	if isinstance(obj, ctypes.Array):
130	n/a	return rebuild_ctype, (obj._type_, obj._wrapper, obj._length_)
131	n/a	else:
132	n/a	return rebuild_ctype, (type(obj), obj._wrapper, None)
133	n/a
134	n/a	def rebuild_ctype(type_, wrapper, length):
135	n/a	if length is not None:
136	n/a	type_ = type_ * length
137	n/a	_ForkingPickler.register(type_, reduce_ctype)
138	n/a	buf = wrapper.create_memoryview()
139	n/a	obj = type_.from_buffer(buf)
140	n/a	obj._wrapper = wrapper
141	n/a	return obj
142	n/a
143	n/a	#
144	n/a	# Function to create properties
145	n/a	#
146	n/a
147	n/a	def make_property(name):
148	n/a	try:
149	n/a	return prop_cache[name]
150	n/a	except KeyError:
151	n/a	d = {}
152	n/a	exec(template % ((name,)*7), d)
153	n/a	prop_cache[name] = d[name]
154	n/a	return d[name]
155	n/a
156	n/a	template = '''
157	n/a	def get%s(self):
158	n/a	self.acquire()
159	n/a	try:
160	n/a	return self._obj.%s
161	n/a	finally:
162	n/a	self.release()
163	n/a	def set%s(self, value):
164	n/a	self.acquire()
165	n/a	try:
166	n/a	self._obj.%s = value
167	n/a	finally:
168	n/a	self.release()
169	n/a	%s = property(get%s, set%s)
170	n/a	'''
171	n/a
172	n/a	prop_cache = {}
173	n/a	class_cache = weakref.WeakKeyDictionary()
174	n/a
175	n/a	#
176	n/a	# Synchronized wrappers
177	n/a	#
178	n/a
179	n/a	class SynchronizedBase(object):
180	n/a
181	n/a	def __init__(self, obj, lock=None, ctx=None):
182	n/a	self._obj = obj
183	n/a	if lock:
184	n/a	self._lock = lock
185	n/a	else:
186	n/a	ctx = ctx or get_context(force=True)
187	n/a	self._lock = ctx.RLock()
188	n/a	self.acquire = self._lock.acquire
189	n/a	self.release = self._lock.release
190	n/a
191	n/a	def __enter__(self):
192	n/a	return self._lock.__enter__()
193	n/a
194	n/a	def __exit__(self, *args):
195	n/a	return self._lock.__exit__(*args)
196	n/a
197	n/a	def __reduce__(self):
198	n/a	assert_spawning(self)
199	n/a	return synchronized, (self._obj, self._lock)
200	n/a
201	n/a	def get_obj(self):
202	n/a	return self._obj
203	n/a
204	n/a	def get_lock(self):
205	n/a	return self._lock
206	n/a
207	n/a	def __repr__(self):
208	n/a	return '<%s wrapper for %s>' % (type(self).__name__, self._obj)
209	n/a
210	n/a
211	n/a	class Synchronized(SynchronizedBase):
212	n/a	value = make_property('value')
213	n/a
214	n/a
215	n/a	class SynchronizedArray(SynchronizedBase):
216	n/a
217	n/a	def __len__(self):
218	n/a	return len(self._obj)
219	n/a
220	n/a	def __getitem__(self, i):
221	n/a	with self:
222	n/a	return self._obj[i]
223	n/a
224	n/a	def __setitem__(self, i, value):
225	n/a	with self:
226	n/a	self._obj[i] = value
227	n/a
228	n/a	def __getslice__(self, start, stop):
229	n/a	with self:
230	n/a	return self._obj[start:stop]
231	n/a
232	n/a	def __setslice__(self, start, stop, values):
233	n/a	with self:
234	n/a	self._obj[start:stop] = values
235	n/a
236	n/a
237	n/a	class SynchronizedString(SynchronizedArray):
238	n/a	value = make_property('value')
239	n/a	raw = make_property('raw')