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 35 import sys 36 import ctypes 37 import weakref 38 39 from multiprocessing import heap, RLock 40 from multiprocessing.forking import assert_spawning, ForkingPickler 41 42 __all__ = ['RawValue', 'RawArray', 'Value', 'Array', 'copy', 'synchronized'] 43 44 # 45 # 46 # 47 48 typecode_to_type = { 49 'c': ctypes.c_char, 'u': ctypes.c_wchar, 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 } 56 57 # 58 # 59 # 60 61 def _new_value(type_): 62 size = ctypes.sizeof(type_) 63 wrapper = heap.BufferWrapper(size) 64 return rebuild_ctype(type_, wrapper, None) 65 66 def RawValue(typecode_or_type, *args): 67 ''' 68 Returns a ctypes object allocated from shared memory 69 ''' 70 type_ = typecode_to_type.get(typecode_or_type, typecode_or_type) 71 obj = _new_value(type_) 72 ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj)) 73 obj.__init__(*args) 74 return obj 75 76 def RawArray(typecode_or_type, size_or_initializer): 77 ''' 78 Returns a ctypes array allocated from shared memory 79 ''' 80 type_ = typecode_to_type.get(typecode_or_type, typecode_or_type) 81 if isinstance(size_or_initializer, (int, long)): 82 type_ = type_ * size_or_initializer 83 obj = _new_value(type_) 84 ctypes.memset(ctypes.addressof(obj), 0, ctypes.sizeof(obj)) 85 return obj 86 else: 87 type_ = type_ * len(size_or_initializer) 88 result = _new_value(type_) 89 result.__init__(*size_or_initializer) 90 return result 91 92 def Value(typecode_or_type, *args, **kwds): 93 ''' 94 Return a synchronization wrapper for a Value 95 ''' 96 lock = kwds.pop('lock', None) 97 if kwds: 98 raise ValueError('unrecognized keyword argument(s): %s' % kwds.keys()) 99 obj = RawValue(typecode_or_type, *args) 100 if lock is False: 101 return obj 102 if lock in (True, None): 103 lock = RLock() 104 if not hasattr(lock, 'acquire'): 105 raise AttributeError("'%r' has no method 'acquire'" % lock) 106 return synchronized(obj, lock) 107 108 def Array(typecode_or_type, size_or_initializer, **kwds): 109 ''' 110 Return a synchronization wrapper for a RawArray 111 ''' 112 lock = kwds.pop('lock', None) 113 if kwds: 114 raise ValueError('unrecognized keyword argument(s): %s' % kwds.keys()) 115 obj = RawArray(typecode_or_type, size_or_initializer) 116 if lock is False: 117 return obj 118 if lock in (True, None): 119 lock = RLock() 120 if not hasattr(lock, 'acquire'): 121 raise AttributeError("'%r' has no method 'acquire'" % lock) 122 return synchronized(obj, lock) 123 124 def copy(obj): 125 new_obj = _new_value(type(obj)) 126 ctypes.pointer(new_obj)[0] = obj 127 return new_obj 128 129 def synchronized(obj, lock=None): 130 assert not isinstance(obj, SynchronizedBase), 'object already synchronized' 131 132 if isinstance(obj, ctypes._SimpleCData): 133 return Synchronized(obj, lock) 134 elif isinstance(obj, ctypes.Array): 135 if obj._type_ is ctypes.c_char: 136 return SynchronizedString(obj, lock) 137 return SynchronizedArray(obj, lock) 138 else: 139 cls = type(obj) 140 try: 141 scls = class_cache[cls] 142 except KeyError: 143 names = [field[0] for field in cls._fields_] 144 d = dict((name, make_property(name)) for name in names) 145 classname = 'Synchronized' + cls.__name__ 146 scls = class_cache[cls] = type(classname, (SynchronizedBase,), d) 147 return scls(obj, lock) 148 149 # 150 # Functions for pickling/unpickling 151 # 152 153 def reduce_ctype(obj): 154 assert_spawning(obj) 155 if isinstance(obj, ctypes.Array): 156 return rebuild_ctype, (obj._type_, obj._wrapper, obj._length_) 157 else: 158 return rebuild_ctype, (type(obj), obj._wrapper, None) 159 160 def rebuild_ctype(type_, wrapper, length): 161 if length is not None: 162 type_ = type_ * length 163 ForkingPickler.register(type_, reduce_ctype) 164 obj = type_.from_address(wrapper.get_address()) 165 obj._wrapper = wrapper 166 return obj 167 168 # 169 # Function to create properties 170 # 171 172 def make_property(name): 173 try: 174 return prop_cache[name] 175 except KeyError: 176 d = {} 177 exec template % ((name,)*7) in d 178 prop_cache[name] = d[name] 179 return d[name] 180 181 template = ''' 182 def get%s(self): 183 self.acquire() 184 try: 185 return self._obj.%s 186 finally: 187 self.release() 188 def set%s(self, value): 189 self.acquire() 190 try: 191 self._obj.%s = value 192 finally: 193 self.release() 194 %s = property(get%s, set%s) 195 ''' 196 197 prop_cache = {} 198 class_cache = weakref.WeakKeyDictionary() 199 200 # 201 # Synchronized wrappers 202 # 203 204 class SynchronizedBase(object): 205 206 def __init__(self, obj, lock=None): 207 self._obj = obj 208 self._lock = lock or RLock() 209 self.acquire = self._lock.acquire 210 self.release = self._lock.release 211 212 def __reduce__(self): 213 assert_spawning(self) 214 return synchronized, (self._obj, self._lock) 215 216 def get_obj(self): 217 return self._obj 218 219 def get_lock(self): 220 return self._lock 221 222 def __repr__(self): 223 return '<%s wrapper for %s>' % (type(self).__name__, self._obj) 224 225 226 class Synchronized(SynchronizedBase): 227 value = make_property('value') 228 229 230 class SynchronizedArray(SynchronizedBase): 231 232 def __len__(self): 233 return len(self._obj) 234 235 def __getitem__(self, i): 236 self.acquire() 237 try: 238 return self._obj[i] 239 finally: 240 self.release() 241 242 def __setitem__(self, i, value): 243 self.acquire() 244 try: 245 self._obj[i] = value 246 finally: 247 self.release() 248 249 def __getslice__(self, start, stop): 250 self.acquire() 251 try: 252 return self._obj[start:stop] 253 finally: 254 self.release() 255 256 def __setslice__(self, start, stop, values): 257 self.acquire() 258 try: 259 self._obj[start:stop] = values 260 finally: 261 self.release() 262 263 264 class SynchronizedString(SynchronizedArray): 265 value = make_property('value') 266 raw = make_property('raw') 267