1# 2# Module which supports allocation of ctypes objects from shared memory 3# 4# multiprocessing/sharedctypes.py 5# 6# Copyright (c) 2006-2008, R Oudkerk 7# All rights reserved. 8# 9# Redistribution and use in source and binary forms, with or without 10# modification, are permitted provided that the following conditions 11# are met: 12# 13# 1. Redistributions of source code must retain the above copyright 14# notice, this list of conditions and the following disclaimer. 15# 2. Redistributions in binary form must reproduce the above copyright 16# notice, this list of conditions and the following disclaimer in the 17# documentation and/or other materials provided with the distribution. 18# 3. Neither the name of author nor the names of any contributors may be 19# used to endorse or promote products derived from this software 20# without specific prior written permission. 21# 22# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND 23# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 26# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32# SUCH DAMAGE. 33# 34 35import sys 36import ctypes 37import weakref 38 39from multiprocessing import heap, RLock 40from multiprocessing.forking import assert_spawning, ForkingPickler 41 42__all__ = ['RawValue', 'RawArray', 'Value', 'Array', 'copy', 'synchronized'] 43 44# 45# 46# 47 48typecode_to_type = { 49 'c': ctypes.c_char, 50 'b': ctypes.c_byte, 'B': ctypes.c_ubyte, 51 'h': ctypes.c_short, 'H': ctypes.c_ushort, 52 'i': ctypes.c_int, 'I': ctypes.c_uint, 53 'l': ctypes.c_long, 'L': ctypes.c_ulong, 54 'f': ctypes.c_float, 'd': ctypes.c_double 55 } 56try: 57 typecode_to_type['u'] = ctypes.c_wchar 58except AttributeError: 59 pass 60 61 62# 63# 64# 65 66def _new_value(type_): 67 size = ctypes.sizeof(type_) 68 wrapper = heap.BufferWrapper(size) 69 return rebuild_ctype(type_, wrapper, None) 70 71def RawValue(typecode_or_type, *args): 72 ''' 73 Returns a ctypes object allocated from shared memory 74 ''' 75 type_ = typecode_to_type.get(typecode_or_type, typecode_or_type) 76 obj = _new_value(type_) 77 ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj)) 78 obj.__init__(*args) 79 return obj 80 81def RawArray(typecode_or_type, size_or_initializer): 82 ''' 83 Returns a ctypes array allocated from shared memory 84 ''' 85 type_ = typecode_to_type.get(typecode_or_type, typecode_or_type) 86 if isinstance(size_or_initializer, (int, long)): 87 type_ = type_ * size_or_initializer 88 obj = _new_value(type_) 89 ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj)) 90 return obj 91 else: 92 type_ = type_ * len(size_or_initializer) 93 result = _new_value(type_) 94 result.__init__(*size_or_initializer) 95 return result 96 97def Value(typecode_or_type, *args, **kwds): 98 ''' 99 Return a synchronization wrapper for a Value 100 ''' 101 lock = kwds.pop('lock', None) 102 if kwds: 103 raise ValueError('unrecognized keyword argument(s): %s' % kwds.keys()) 104 obj = RawValue(typecode_or_type, *args) 105 if lock is False: 106 return obj 107 if lock in (True, None): 108 lock = RLock() 109 if not hasattr(lock, 'acquire'): 110 raise AttributeError("'%r' has no method 'acquire'" % lock) 111 return synchronized(obj, lock) 112 113def Array(typecode_or_type, size_or_initializer, **kwds): 114 ''' 115 Return a synchronization wrapper for a RawArray 116 ''' 117 lock = kwds.pop('lock', None) 118 if kwds: 119 raise ValueError('unrecognized keyword argument(s): %s' % kwds.keys()) 120 obj = RawArray(typecode_or_type, size_or_initializer) 121 if lock is False: 122 return obj 123 if lock in (True, None): 124 lock = RLock() 125 if not hasattr(lock, 'acquire'): 126 raise AttributeError("'%r' has no method 'acquire'" % lock) 127 return synchronized(obj, lock) 128 129def copy(obj): 130 new_obj = _new_value(type(obj)) 131 ctypes.pointer(new_obj)[0] = obj 132 return new_obj 133 134def synchronized(obj, lock=None): 135 assert not isinstance(obj, SynchronizedBase), 'object already synchronized' 136 137 if isinstance(obj, ctypes._SimpleCData): 138 return Synchronized(obj, lock) 139 elif isinstance(obj, ctypes.Array): 140 if obj._type_ is ctypes.c_char: 141 return SynchronizedString(obj, lock) 142 return SynchronizedArray(obj, lock) 143 else: 144 cls = type(obj) 145 try: 146 scls = class_cache[cls] 147 except KeyError: 148 names = [field[0] for field in cls._fields_] 149 d = dict((name, make_property(name)) for name in names) 150 classname = 'Synchronized' + cls.__name__ 151 scls = class_cache[cls] = type(classname, (SynchronizedBase,), d) 152 return scls(obj, lock) 153 154# 155# Functions for pickling/unpickling 156# 157 158def reduce_ctype(obj): 159 assert_spawning(obj) 160 if isinstance(obj, ctypes.Array): 161 return rebuild_ctype, (obj._type_, obj._wrapper, obj._length_) 162 else: 163 return rebuild_ctype, (type(obj), obj._wrapper, None) 164 165def rebuild_ctype(type_, wrapper, length): 166 if length is not None: 167 type_ = type_ * length 168 ForkingPickler.register(type_, reduce_ctype) 169 obj = type_.from_address(wrapper.get_address()) 170 obj._wrapper = wrapper 171 return obj 172 173# 174# Function to create properties 175# 176 177def make_property(name): 178 try: 179 return prop_cache[name] 180 except KeyError: 181 d = {} 182 exec template % ((name,)*7) in d 183 prop_cache[name] = d[name] 184 return d[name] 185 186template = ''' 187def get%s(self): 188 self.acquire() 189 try: 190 return self._obj.%s 191 finally: 192 self.release() 193def set%s(self, value): 194 self.acquire() 195 try: 196 self._obj.%s = value 197 finally: 198 self.release() 199%s = property(get%s, set%s) 200''' 201 202prop_cache = {} 203class_cache = weakref.WeakKeyDictionary() 204 205# 206# Synchronized wrappers 207# 208 209class SynchronizedBase(object): 210 211 def __init__(self, obj, lock=None): 212 self._obj = obj 213 self._lock = lock or RLock() 214 self.acquire = self._lock.acquire 215 self.release = self._lock.release 216 217 def __reduce__(self): 218 assert_spawning(self) 219 return synchronized, (self._obj, self._lock) 220 221 def get_obj(self): 222 return self._obj 223 224 def get_lock(self): 225 return self._lock 226 227 def __repr__(self): 228 return '<%s wrapper for %s>' % (type(self).__name__, self._obj) 229 230 231class Synchronized(SynchronizedBase): 232 value = make_property('value') 233 234 235class SynchronizedArray(SynchronizedBase): 236 237 def __len__(self): 238 return len(self._obj) 239 240 def __getitem__(self, i): 241 self.acquire() 242 try: 243 return self._obj[i] 244 finally: 245 self.release() 246 247 def __setitem__(self, i, value): 248 self.acquire() 249 try: 250 self._obj[i] = value 251 finally: 252 self.release() 253 254 def __getslice__(self, start, stop): 255 self.acquire() 256 try: 257 return self._obj[start:stop] 258 finally: 259 self.release() 260 261 def __setslice__(self, start, stop, values): 262 self.acquire() 263 try: 264 self._obj[start:stop] = values 265 finally: 266 self.release() 267 268 269class SynchronizedString(SynchronizedArray): 270 value = make_property('value') 271 raw = make_property('raw') 272