/usr/share/pyshared/protocols/interfaces.py is in python-protocols 1.0a.svn20070625-5build1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 | """Implement Interfaces and define the interfaces used by the package"""
from __future__ import generators
__all__ = [
'Protocol', 'InterfaceClass', 'Interface',
'AbstractBase', 'AbstractBaseMeta',
'IAdapterFactory', 'IProtocol',
'IAdaptingProtocol', 'IOpenProtocol', 'IOpenProvider',
'IOpenImplementor', 'IImplicationListener', 'Attribute', 'Variation'
]
import api
from advice import metamethod, classicMRO, mkRef
from adapters import composeAdapters, updateWithSimplestAdapter
from adapters import NO_ADAPTER_NEEDED, DOES_NOT_SUPPORT
from types import InstanceType
# Thread locking support
try:
from thread import allocate_lock
except ImportError:
try:
from dummy_thread import allocate_lock
except ImportError:
class allocate_lock(object):
__slots__ = ()
def acquire(*args): pass
def release(*args): pass
# Trivial interface implementation
class Protocol:
"""Generic protocol w/type-based adapter registry"""
def __init__(self):
self.__adapters = {}
self.__implies = {}
self.__listeners = None
self.__lock = allocate_lock()
def getImpliedProtocols(self):
# This is messy so it can clean out weakrefs, but this method is only
# called for declaration activities and is thus not at all
# speed-critical. It's more important that we support weak refs to
# implied protocols, so that dynamically created subset protocols can
# be garbage collected.
out = []
add = out.append
self.__lock.acquire() # we might clean out dead weakrefs
try:
for k,v in self.__implies.items():
proto = k()
if proto is None:
del self.__implies[k]
else:
add((proto,v))
return out
finally:
self.__lock.release()
def addImpliedProtocol(self,proto,adapter=NO_ADAPTER_NEEDED,depth=1):
self.__lock.acquire()
try:
key = mkRef(proto)
if not updateWithSimplestAdapter(
self.__implies, key, adapter, depth
):
return self.__implies[key][0]
finally:
self.__lock.release()
# Always register implied protocol with classes, because they should
# know if we break the implication link between two protocols
for klass,(baseAdapter,d) in self.__adapters.items():
api.declareAdapterForType(
proto,composeAdapters(baseAdapter,self,adapter),klass,depth+d
)
if self.__listeners:
for listener in self.__listeners.keys(): # Must use keys()!
listener.newProtocolImplied(self, proto, adapter, depth)
return adapter
addImpliedProtocol = metamethod(addImpliedProtocol)
def registerImplementation(self,klass,adapter=NO_ADAPTER_NEEDED,depth=1):
self.__lock.acquire()
try:
if not updateWithSimplestAdapter(
self.__adapters,klass,adapter,depth
):
return self.__adapters[klass][0]
finally:
self.__lock.release()
if adapter is DOES_NOT_SUPPORT:
# Don't register non-support with implied protocols, because
# "X implies Y" and "not X" doesn't imply "not Y". In effect,
# explicitly registering DOES_NOT_SUPPORT for a type is just a
# way to "disinherit" a superclass' claim to support something.
return adapter
for proto, (extender,d) in self.getImpliedProtocols():
api.declareAdapterForType(
proto, composeAdapters(adapter,self,extender), klass, depth+d
)
return adapter
registerImplementation = metamethod(registerImplementation)
def registerObject(self, ob, adapter=NO_ADAPTER_NEEDED,depth=1):
# Object needs to be able to handle registration
if api.adapt(ob,IOpenProvider).declareProvides(self,adapter,depth):
if adapter is DOES_NOT_SUPPORT:
return # non-support doesn't imply non-support of implied
# Handle implied protocols
for proto, (extender,d) in self.getImpliedProtocols():
api.declareAdapterForObject(
proto, composeAdapters(adapter,self,extender), ob, depth+d
)
registerObject = metamethod(registerObject)
def __adapt__(self, obj):
get = self.__adapters.get
try:
typ = obj.__class__
except AttributeError:
typ = type(obj)
try:
mro = typ.__mro__
except AttributeError:
# Note: this adds 'InstanceType' and 'object' to end of MRO
mro = classicMRO(typ,extendedClassic=True)
for klass in mro:
factory=get(klass)
if factory is not None:
return factory[0](obj)
try:
from _speedups import Protocol__adapt__ as __adapt__
except ImportError:
pass
__adapt__ = metamethod(__adapt__)
def addImplicationListener(self, listener):
self.__lock.acquire()
try:
if self.__listeners is None:
from weakref import WeakKeyDictionary
self.__listeners = WeakKeyDictionary()
self.__listeners[listener] = 1
finally:
self.__lock.release()
addImplicationListener = metamethod(addImplicationListener)
def __call__(self, ob, default=api._marker):
"""Adapt to this protocol"""
return api.adapt(ob,self,default)
# Use faster __call__ method, if possible
# XXX it could be even faster if the __call__ were in the tp_call slot
# XXX directly, but Pyrex doesn't have a way to do that AFAIK.
try:
from _speedups import Protocol__call__
except ImportError:
pass
else:
from new import instancemethod
Protocol.__call__ = instancemethod(Protocol__call__, None, Protocol)
class AbstractBaseMeta(Protocol, type):
"""Metaclass for 'AbstractBase' - a protocol that's also a class
(Note that this should not be used as an explicit metaclass - always
subclass from 'AbstractBase' or 'Interface' instead.)
"""
def __init__(self, __name__, __bases__, __dict__):
type.__init__(self, __name__, __bases__, __dict__)
Protocol.__init__(self)
for b in __bases__:
if isinstance(b,AbstractBaseMeta) and b.__bases__<>(object,):
self.addImpliedProtocol(b)
def __setattr__(self,attr,val):
# We could probably support changing __bases__, as long as we checked
# that no bases are *removed*. But it'd be a pain, since we'd
# have to do callbacks, remove entries from our __implies registry,
# etc. So just punt for now.
if attr=='__bases__':
raise TypeError(
"Can't change interface __bases__", self
)
type.__setattr__(self,attr,val)
__call__ = type.__call__
class AbstractBase(object):
"""Base class for a protocol that's a class"""
__metaclass__ = AbstractBaseMeta
class InterfaceClass(AbstractBaseMeta):
"""Metaclass for 'Interface' - a non-instantiable protocol
(Note that this should not be used as an explicit metaclass - always
subclass from 'AbstractBase' or 'Interface' instead.)
"""
def __call__(self, *__args, **__kw):
if self.__init__ is Interface.__init__:
return Protocol.__call__(self,*__args, **__kw)
else:
return type.__call__(self,*__args, **__kw)
def getBases(self):
return [
b for b in self.__bases__
if isinstance(b,AbstractBaseMeta) and b.__bases__<>(object,)
]
class Interface(object):
__metaclass__ = InterfaceClass
class Variation(Protocol):
"""A variation of a base protocol - "inherits" the base's adapters
See the 'LocalProtocol' example in the reference manual for more info.
"""
def __init__(self, baseProtocol, context = None):
self.baseProtocol = baseProtocol
self.context = context
# Note: Protocol is a ``classic'' class, so we don't use super()
Protocol.__init__(self)
api.declareAdapterForProtocol(self,NO_ADAPTER_NEEDED,baseProtocol)
def __repr__(self):
if self.context is None:
return "Variation(%r)" % self.baseProtocol
return "Variation(%r,%r)" % (self.baseProtocol, self.context)
# Semi-backward compatible 'interface.Attribute'
class Attribute(object):
"""Attribute declaration; should we get rid of this?"""
def __init__(self,doc,name=None,value=None):
self.__doc__ = doc
self.name = name
self.value = value
def __get__(self,ob,typ=None):
if ob is None:
return self
if not self.name:
raise NotImplementedError("Abstract attribute")
try:
return ob.__dict__[self.name]
except KeyError:
return self.value
def __set__(self,ob,val):
if not self.name:
raise NotImplementedError("Abstract attribute")
ob.__dict__[self.name] = val
def __delete__(self,ob):
if not self.name:
raise NotImplementedError("Abstract attribute")
del ob.__dict__[self.name]
def __repr__(self):
return "Attribute: %s" % self.__doc__
# Interfaces and adapters for declaring protocol/type/object relationships
class IAdapterFactory(Interface):
"""Callable that can adapt an object to a protocol"""
def __call__(ob):
"""Return an implementation of protocol for 'ob'"""
class IProtocol(Interface):
"""Object usable as a protocol by 'adapt()'"""
def __hash__():
"""Protocols must be usable as dictionary keys"""
def __eq__(other):
"""Protocols must be comparable with == and !="""
def __ne__(other):
"""Protocols must be comparable with == and !="""
class IAdaptingProtocol(IProtocol):
"""A protocol that potentially knows how to adapt some object to itself"""
def __adapt__(ob):
"""Return 'ob' adapted to protocol, or 'None'"""
class IConformingObject(Interface):
"""An object that potentially knows how to adapt to a protocol"""
def __conform__(protocol):
"""Return an implementation of 'protocol' for self, or 'None'"""
class IOpenProvider(Interface):
"""An object that can be told how to adapt to protocols"""
def declareProvides(protocol, adapter=NO_ADAPTER_NEEDED, depth=1):
"""Register 'adapter' as providing 'protocol' for this object
Return a true value if the provided adapter is the "shortest path" to
'protocol' for the object, or false if a shorter path already existed.
"""
class IOpenImplementor(Interface):
"""Object/type that can be told how its instances adapt to protocols"""
def declareClassImplements(protocol, adapter=NO_ADAPTER_NEEDED, depth=1):
"""Register 'adapter' as implementing 'protocol' for instances"""
class IOpenProtocol(IAdaptingProtocol):
"""A protocol that be told what it implies, and what supports it
Note that these methods are for the use of the declaration APIs only,
and you should NEVER call them directly."""
def addImpliedProtocol(proto, adapter=NO_ADAPTER_NEEDED, depth=1):
"""'adapter' provides conversion from this protocol to 'proto'"""
def registerImplementation(klass, adapter=NO_ADAPTER_NEEDED, depth=1):
"""'adapter' provides protocol for instances of klass"""
def registerObject(ob, adapter=NO_ADAPTER_NEEDED, depth=1):
"""'adapter' provides protocol for 'ob' directly"""
def addImplicationListener(listener):
"""Notify 'listener' whenever protocol has new implied protocol"""
class IImplicationListener(Interface):
def newProtocolImplied(srcProto, destProto, adapter, depth):
"""'srcProto' now implies 'destProto' via 'adapter' at 'depth'"""
|