| # |
| # 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') |