Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 1 | /* ABCMeta implementation */ |
| 2 | |
| 3 | #include "Python.h" |
| 4 | #include "structmember.h" |
| 5 | #include "clinic/_abc.c.h" |
| 6 | |
| 7 | /*[clinic input] |
| 8 | module _abc |
| 9 | [clinic start generated code]*/ |
| 10 | /*[clinic end generated code: output=da39a3ee5e6b4b0d input=964f5328e1aefcda]*/ |
| 11 | |
| 12 | PyDoc_STRVAR(_abc__doc__, |
| 13 | "Module contains faster C implementation of abc.ABCMeta"); |
| 14 | |
| 15 | _Py_IDENTIFIER(__abstractmethods__); |
| 16 | _Py_IDENTIFIER(__class__); |
| 17 | _Py_IDENTIFIER(__dict__); |
| 18 | _Py_IDENTIFIER(__bases__); |
| 19 | _Py_IDENTIFIER(_abc_impl); |
| 20 | _Py_IDENTIFIER(__subclasscheck__); |
| 21 | _Py_IDENTIFIER(__subclasshook__); |
| 22 | |
| 23 | /* A global counter that is incremented each time a class is |
| 24 | registered as a virtual subclass of anything. It forces the |
| 25 | negative cache to be cleared before its next use. |
| 26 | Note: this counter is private. Use `abc.get_cache_token()` for |
| 27 | external code. */ |
| 28 | static unsigned long long abc_invalidation_counter = 0; |
| 29 | |
| 30 | /* This object stores internal state for ABCs. |
| 31 | Note that we can use normal sets for caches, |
| 32 | since they are never iterated over. */ |
| 33 | typedef struct { |
| 34 | PyObject_HEAD |
| 35 | PyObject *_abc_registry; |
| 36 | PyObject *_abc_cache; /* Normal set of weak references. */ |
| 37 | PyObject *_abc_negative_cache; /* Normal set of weak references. */ |
| 38 | unsigned long long _abc_negative_cache_version; |
| 39 | } _abc_data; |
| 40 | |
| 41 | static void |
| 42 | abc_data_dealloc(_abc_data *self) |
| 43 | { |
| 44 | Py_XDECREF(self->_abc_registry); |
| 45 | Py_XDECREF(self->_abc_cache); |
| 46 | Py_XDECREF(self->_abc_negative_cache); |
| 47 | Py_TYPE(self)->tp_free(self); |
| 48 | } |
| 49 | |
| 50 | static PyObject * |
| 51 | abc_data_new(PyTypeObject *type, PyObject *args, PyObject *kwds) |
| 52 | { |
| 53 | _abc_data *self = (_abc_data *) type->tp_alloc(type, 0); |
| 54 | if (self == NULL) { |
| 55 | return NULL; |
| 56 | } |
| 57 | |
| 58 | self->_abc_registry = NULL; |
| 59 | self->_abc_cache = NULL; |
| 60 | self->_abc_negative_cache = NULL; |
| 61 | self->_abc_negative_cache_version = abc_invalidation_counter; |
| 62 | return (PyObject *) self; |
| 63 | } |
| 64 | |
| 65 | PyDoc_STRVAR(abc_data_doc, |
| 66 | "Internal state held by ABC machinery."); |
| 67 | |
| 68 | static PyTypeObject _abc_data_type = { |
| 69 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| 70 | "_abc_data", /*tp_name*/ |
Peter Eisentraut | 0e0bc4e | 2018-09-10 18:46:08 +0200 | [diff] [blame] | 71 | sizeof(_abc_data), /*tp_basicsize*/ |
Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 72 | .tp_dealloc = (destructor)abc_data_dealloc, |
| 73 | .tp_flags = Py_TPFLAGS_DEFAULT, |
| 74 | .tp_alloc = PyType_GenericAlloc, |
| 75 | .tp_new = abc_data_new, |
| 76 | }; |
| 77 | |
| 78 | static _abc_data * |
| 79 | _get_impl(PyObject *self) |
| 80 | { |
| 81 | PyObject *impl = _PyObject_GetAttrId(self, &PyId__abc_impl); |
| 82 | if (impl == NULL) { |
| 83 | return NULL; |
| 84 | } |
| 85 | if (Py_TYPE(impl) != &_abc_data_type) { |
| 86 | PyErr_SetString(PyExc_TypeError, "_abc_impl is set to a wrong type"); |
| 87 | Py_DECREF(impl); |
| 88 | return NULL; |
| 89 | } |
| 90 | return (_abc_data *)impl; |
| 91 | } |
| 92 | |
| 93 | static int |
| 94 | _in_weak_set(PyObject *set, PyObject *obj) |
| 95 | { |
| 96 | if (set == NULL || PySet_GET_SIZE(set) == 0) { |
| 97 | return 0; |
| 98 | } |
| 99 | PyObject *ref = PyWeakref_NewRef(obj, NULL); |
| 100 | if (ref == NULL) { |
| 101 | if (PyErr_ExceptionMatches(PyExc_TypeError)) { |
| 102 | PyErr_Clear(); |
| 103 | return 0; |
| 104 | } |
| 105 | return -1; |
| 106 | } |
| 107 | int res = PySet_Contains(set, ref); |
| 108 | Py_DECREF(ref); |
| 109 | return res; |
| 110 | } |
| 111 | |
| 112 | static PyObject * |
| 113 | _destroy(PyObject *setweakref, PyObject *objweakref) |
| 114 | { |
| 115 | PyObject *set; |
| 116 | set = PyWeakref_GET_OBJECT(setweakref); |
| 117 | if (set == Py_None) { |
| 118 | Py_RETURN_NONE; |
| 119 | } |
| 120 | Py_INCREF(set); |
| 121 | if (PySet_Discard(set, objweakref) < 0) { |
| 122 | Py_DECREF(set); |
| 123 | return NULL; |
| 124 | } |
| 125 | Py_DECREF(set); |
| 126 | Py_RETURN_NONE; |
| 127 | } |
| 128 | |
| 129 | static PyMethodDef _destroy_def = { |
| 130 | "_destroy", (PyCFunction) _destroy, METH_O |
| 131 | }; |
| 132 | |
| 133 | static int |
| 134 | _add_to_weak_set(PyObject **pset, PyObject *obj) |
| 135 | { |
| 136 | if (*pset == NULL) { |
| 137 | *pset = PySet_New(NULL); |
| 138 | if (*pset == NULL) { |
| 139 | return -1; |
| 140 | } |
| 141 | } |
| 142 | |
| 143 | PyObject *set = *pset; |
| 144 | PyObject *ref, *wr; |
| 145 | PyObject *destroy_cb; |
| 146 | wr = PyWeakref_NewRef(set, NULL); |
| 147 | if (wr == NULL) { |
| 148 | return -1; |
| 149 | } |
| 150 | destroy_cb = PyCFunction_NewEx(&_destroy_def, wr, NULL); |
| 151 | if (destroy_cb == NULL) { |
| 152 | Py_DECREF(wr); |
| 153 | return -1; |
| 154 | } |
| 155 | ref = PyWeakref_NewRef(obj, destroy_cb); |
| 156 | Py_DECREF(destroy_cb); |
| 157 | if (ref == NULL) { |
| 158 | Py_DECREF(wr); |
| 159 | return -1; |
| 160 | } |
| 161 | int ret = PySet_Add(set, ref); |
| 162 | Py_DECREF(wr); |
| 163 | Py_DECREF(ref); |
| 164 | return ret; |
| 165 | } |
| 166 | |
| 167 | /*[clinic input] |
| 168 | _abc._reset_registry |
| 169 | |
| 170 | self: object |
| 171 | / |
| 172 | |
| 173 | Internal ABC helper to reset registry of a given class. |
| 174 | |
| 175 | Should be only used by refleak.py |
| 176 | [clinic start generated code]*/ |
| 177 | |
| 178 | static PyObject * |
| 179 | _abc__reset_registry(PyObject *module, PyObject *self) |
| 180 | /*[clinic end generated code: output=92d591a43566cc10 input=12a0b7eb339ac35c]*/ |
| 181 | { |
| 182 | _abc_data *impl = _get_impl(self); |
| 183 | if (impl == NULL) { |
| 184 | return NULL; |
| 185 | } |
| 186 | if (impl->_abc_registry != NULL && PySet_Clear(impl->_abc_registry) < 0) { |
| 187 | Py_DECREF(impl); |
| 188 | return NULL; |
| 189 | } |
| 190 | Py_DECREF(impl); |
| 191 | Py_RETURN_NONE; |
| 192 | } |
| 193 | |
| 194 | /*[clinic input] |
| 195 | _abc._reset_caches |
| 196 | |
| 197 | self: object |
| 198 | / |
| 199 | |
| 200 | Internal ABC helper to reset both caches of a given class. |
| 201 | |
| 202 | Should be only used by refleak.py |
| 203 | [clinic start generated code]*/ |
| 204 | |
| 205 | static PyObject * |
| 206 | _abc__reset_caches(PyObject *module, PyObject *self) |
| 207 | /*[clinic end generated code: output=f296f0d5c513f80c input=c0ac616fd8acfb6f]*/ |
| 208 | { |
| 209 | _abc_data *impl = _get_impl(self); |
| 210 | if (impl == NULL) { |
| 211 | return NULL; |
| 212 | } |
| 213 | if (impl->_abc_cache != NULL && PySet_Clear(impl->_abc_cache) < 0) { |
| 214 | Py_DECREF(impl); |
| 215 | return NULL; |
| 216 | } |
| 217 | /* also the second cache */ |
| 218 | if (impl->_abc_negative_cache != NULL && |
| 219 | PySet_Clear(impl->_abc_negative_cache) < 0) { |
| 220 | Py_DECREF(impl); |
| 221 | return NULL; |
| 222 | } |
| 223 | Py_DECREF(impl); |
| 224 | Py_RETURN_NONE; |
| 225 | } |
| 226 | |
| 227 | /*[clinic input] |
| 228 | _abc._get_dump |
| 229 | |
| 230 | self: object |
| 231 | / |
| 232 | |
| 233 | Internal ABC helper for cache and registry debugging. |
| 234 | |
| 235 | Return shallow copies of registry, of both caches, and |
| 236 | negative cache version. Don't call this function directly, |
| 237 | instead use ABC._dump_registry() for a nice repr. |
| 238 | [clinic start generated code]*/ |
| 239 | |
| 240 | static PyObject * |
| 241 | _abc__get_dump(PyObject *module, PyObject *self) |
| 242 | /*[clinic end generated code: output=9d9569a8e2c1c443 input=2c5deb1bfe9e3c79]*/ |
| 243 | { |
| 244 | _abc_data *impl = _get_impl(self); |
| 245 | if (impl == NULL) { |
| 246 | return NULL; |
| 247 | } |
| 248 | PyObject *res = Py_BuildValue("NNNK", |
| 249 | PySet_New(impl->_abc_registry), |
| 250 | PySet_New(impl->_abc_cache), |
| 251 | PySet_New(impl->_abc_negative_cache), |
| 252 | impl->_abc_negative_cache_version); |
| 253 | Py_DECREF(impl); |
| 254 | return res; |
| 255 | } |
| 256 | |
| 257 | // Compute set of abstract method names. |
| 258 | static int |
| 259 | compute_abstract_methods(PyObject *self) |
| 260 | { |
| 261 | int ret = -1; |
| 262 | PyObject *abstracts = PyFrozenSet_New(NULL); |
| 263 | if (abstracts == NULL) { |
| 264 | return -1; |
| 265 | } |
| 266 | |
| 267 | PyObject *ns = NULL, *items = NULL, *bases = NULL; // Py_XDECREF()ed on error. |
| 268 | |
| 269 | /* Stage 1: direct abstract methods. */ |
| 270 | ns = _PyObject_GetAttrId(self, &PyId___dict__); |
| 271 | if (!ns) { |
| 272 | goto error; |
| 273 | } |
| 274 | |
| 275 | // We can't use PyDict_Next(ns) even when ns is dict because |
| 276 | // _PyObject_IsAbstract() can mutate ns. |
| 277 | items = PyMapping_Items(ns); |
| 278 | if (!items) { |
| 279 | goto error; |
| 280 | } |
| 281 | assert(PyList_Check(items)); |
| 282 | for (Py_ssize_t pos = 0; pos < PyList_GET_SIZE(items); pos++) { |
| 283 | PyObject *it = PySequence_Fast( |
| 284 | PyList_GET_ITEM(items, pos), |
| 285 | "items() returned non-iterable"); |
| 286 | if (!it) { |
| 287 | goto error; |
| 288 | } |
| 289 | if (PySequence_Fast_GET_SIZE(it) != 2) { |
| 290 | PyErr_SetString(PyExc_TypeError, |
| 291 | "items() returned item which size is not 2"); |
| 292 | Py_DECREF(it); |
| 293 | goto error; |
| 294 | } |
| 295 | |
| 296 | // borrowed |
| 297 | PyObject *key = PySequence_Fast_GET_ITEM(it, 0); |
| 298 | PyObject *value = PySequence_Fast_GET_ITEM(it, 1); |
| 299 | // items or it may be cleared while accessing __abstractmethod__ |
| 300 | // So we need to keep strong reference for key |
| 301 | Py_INCREF(key); |
| 302 | int is_abstract = _PyObject_IsAbstract(value); |
| 303 | if (is_abstract < 0 || |
| 304 | (is_abstract && PySet_Add(abstracts, key) < 0)) { |
| 305 | Py_DECREF(it); |
| 306 | Py_DECREF(key); |
| 307 | goto error; |
| 308 | } |
| 309 | Py_DECREF(key); |
| 310 | Py_DECREF(it); |
| 311 | } |
| 312 | |
| 313 | /* Stage 2: inherited abstract methods. */ |
| 314 | bases = _PyObject_GetAttrId(self, &PyId___bases__); |
| 315 | if (!bases) { |
| 316 | goto error; |
| 317 | } |
| 318 | if (!PyTuple_Check(bases)) { |
| 319 | PyErr_SetString(PyExc_TypeError, "__bases__ is not tuple"); |
| 320 | goto error; |
| 321 | } |
| 322 | |
| 323 | for (Py_ssize_t pos = 0; pos < PyTuple_GET_SIZE(bases); pos++) { |
| 324 | PyObject *item = PyTuple_GET_ITEM(bases, pos); // borrowed |
| 325 | PyObject *base_abstracts, *iter; |
| 326 | |
| 327 | if (_PyObject_LookupAttrId(item, &PyId___abstractmethods__, |
| 328 | &base_abstracts) < 0) { |
| 329 | goto error; |
| 330 | } |
| 331 | if (base_abstracts == NULL) { |
| 332 | continue; |
| 333 | } |
| 334 | if (!(iter = PyObject_GetIter(base_abstracts))) { |
| 335 | Py_DECREF(base_abstracts); |
| 336 | goto error; |
| 337 | } |
| 338 | Py_DECREF(base_abstracts); |
| 339 | PyObject *key, *value; |
| 340 | while ((key = PyIter_Next(iter))) { |
| 341 | if (_PyObject_LookupAttr(self, key, &value) < 0) { |
| 342 | Py_DECREF(key); |
| 343 | Py_DECREF(iter); |
| 344 | goto error; |
| 345 | } |
| 346 | if (value == NULL) { |
| 347 | Py_DECREF(key); |
| 348 | continue; |
| 349 | } |
| 350 | |
| 351 | int is_abstract = _PyObject_IsAbstract(value); |
| 352 | Py_DECREF(value); |
| 353 | if (is_abstract < 0 || |
| 354 | (is_abstract && PySet_Add(abstracts, key) < 0)) |
| 355 | { |
| 356 | Py_DECREF(key); |
| 357 | Py_DECREF(iter); |
| 358 | goto error; |
| 359 | } |
| 360 | Py_DECREF(key); |
| 361 | } |
| 362 | Py_DECREF(iter); |
| 363 | if (PyErr_Occurred()) { |
| 364 | goto error; |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | if (_PyObject_SetAttrId(self, &PyId___abstractmethods__, abstracts) < 0) { |
| 369 | goto error; |
| 370 | } |
| 371 | |
| 372 | ret = 0; |
| 373 | error: |
| 374 | Py_DECREF(abstracts); |
| 375 | Py_XDECREF(ns); |
| 376 | Py_XDECREF(items); |
| 377 | Py_XDECREF(bases); |
| 378 | return ret; |
| 379 | } |
| 380 | |
| 381 | /*[clinic input] |
| 382 | _abc._abc_init |
| 383 | |
| 384 | self: object |
| 385 | / |
| 386 | |
| 387 | Internal ABC helper for class set-up. Should be never used outside abc module. |
| 388 | [clinic start generated code]*/ |
| 389 | |
| 390 | static PyObject * |
| 391 | _abc__abc_init(PyObject *module, PyObject *self) |
| 392 | /*[clinic end generated code: output=594757375714cda1 input=8d7fe470ff77f029]*/ |
| 393 | { |
| 394 | PyObject *data; |
| 395 | if (compute_abstract_methods(self) < 0) { |
| 396 | return NULL; |
| 397 | } |
| 398 | |
| 399 | /* Set up inheritance registry. */ |
| 400 | data = abc_data_new(&_abc_data_type, NULL, NULL); |
| 401 | if (data == NULL) { |
| 402 | return NULL; |
| 403 | } |
| 404 | if (_PyObject_SetAttrId(self, &PyId__abc_impl, data) < 0) { |
| 405 | Py_DECREF(data); |
| 406 | return NULL; |
| 407 | } |
| 408 | Py_DECREF(data); |
| 409 | Py_RETURN_NONE; |
| 410 | } |
| 411 | |
| 412 | /*[clinic input] |
| 413 | _abc._abc_register |
| 414 | |
| 415 | self: object |
| 416 | subclass: object |
| 417 | / |
| 418 | |
| 419 | Internal ABC helper for subclasss registration. Should be never used outside abc module. |
| 420 | [clinic start generated code]*/ |
| 421 | |
| 422 | static PyObject * |
| 423 | _abc__abc_register_impl(PyObject *module, PyObject *self, PyObject *subclass) |
| 424 | /*[clinic end generated code: output=7851e7668c963524 input=ca589f8c3080e67f]*/ |
| 425 | { |
| 426 | if (!PyType_Check(subclass)) { |
| 427 | PyErr_SetString(PyExc_TypeError, "Can only register classes"); |
| 428 | return NULL; |
| 429 | } |
| 430 | int result = PyObject_IsSubclass(subclass, self); |
| 431 | if (result > 0) { |
| 432 | Py_INCREF(subclass); |
| 433 | return subclass; /* Already a subclass. */ |
| 434 | } |
| 435 | if (result < 0) { |
| 436 | return NULL; |
| 437 | } |
| 438 | /* Subtle: test for cycles *after* testing for "already a subclass"; |
| 439 | this means we allow X.register(X) and interpret it as a no-op. */ |
| 440 | result = PyObject_IsSubclass(self, subclass); |
| 441 | if (result > 0) { |
| 442 | /* This would create a cycle, which is bad for the algorithm below. */ |
| 443 | PyErr_SetString(PyExc_RuntimeError, "Refusing to create an inheritance cycle"); |
| 444 | return NULL; |
| 445 | } |
| 446 | if (result < 0) { |
| 447 | return NULL; |
| 448 | } |
| 449 | _abc_data *impl = _get_impl(self); |
| 450 | if (impl == NULL) { |
| 451 | return NULL; |
| 452 | } |
| 453 | if (_add_to_weak_set(&impl->_abc_registry, subclass) < 0) { |
| 454 | Py_DECREF(impl); |
| 455 | return NULL; |
| 456 | } |
| 457 | Py_DECREF(impl); |
| 458 | |
| 459 | /* Invalidate negative cache */ |
| 460 | abc_invalidation_counter++; |
| 461 | |
| 462 | Py_INCREF(subclass); |
| 463 | return subclass; |
| 464 | } |
| 465 | |
| 466 | |
| 467 | /*[clinic input] |
| 468 | _abc._abc_instancecheck |
| 469 | |
| 470 | self: object |
| 471 | instance: object |
| 472 | / |
| 473 | |
| 474 | Internal ABC helper for instance checks. Should be never used outside abc module. |
| 475 | [clinic start generated code]*/ |
| 476 | |
| 477 | static PyObject * |
| 478 | _abc__abc_instancecheck_impl(PyObject *module, PyObject *self, |
| 479 | PyObject *instance) |
| 480 | /*[clinic end generated code: output=b8b5148f63b6b56f input=a4f4525679261084]*/ |
| 481 | { |
| 482 | PyObject *subtype, *result = NULL, *subclass = NULL; |
| 483 | _abc_data *impl = _get_impl(self); |
| 484 | if (impl == NULL) { |
| 485 | return NULL; |
| 486 | } |
| 487 | |
| 488 | subclass = _PyObject_GetAttrId(instance, &PyId___class__); |
| 489 | if (subclass == NULL) { |
| 490 | Py_DECREF(impl); |
| 491 | return NULL; |
| 492 | } |
| 493 | /* Inline the cache checking. */ |
| 494 | int incache = _in_weak_set(impl->_abc_cache, subclass); |
| 495 | if (incache < 0) { |
| 496 | goto end; |
| 497 | } |
| 498 | if (incache > 0) { |
| 499 | result = Py_True; |
| 500 | Py_INCREF(result); |
| 501 | goto end; |
| 502 | } |
| 503 | subtype = (PyObject *)Py_TYPE(instance); |
| 504 | if (subtype == subclass) { |
| 505 | if (impl->_abc_negative_cache_version == abc_invalidation_counter) { |
| 506 | incache = _in_weak_set(impl->_abc_negative_cache, subclass); |
| 507 | if (incache < 0) { |
| 508 | goto end; |
| 509 | } |
| 510 | if (incache > 0) { |
| 511 | result = Py_False; |
| 512 | Py_INCREF(result); |
| 513 | goto end; |
| 514 | } |
| 515 | } |
| 516 | /* Fall back to the subclass check. */ |
| 517 | result = _PyObject_CallMethodIdObjArgs(self, &PyId___subclasscheck__, |
| 518 | subclass, NULL); |
| 519 | goto end; |
| 520 | } |
| 521 | result = _PyObject_CallMethodIdObjArgs(self, &PyId___subclasscheck__, |
| 522 | subclass, NULL); |
| 523 | if (result == NULL) { |
| 524 | goto end; |
| 525 | } |
| 526 | |
| 527 | switch (PyObject_IsTrue(result)) { |
| 528 | case -1: |
| 529 | Py_DECREF(result); |
| 530 | result = NULL; |
| 531 | break; |
| 532 | case 0: |
| 533 | Py_DECREF(result); |
| 534 | result = _PyObject_CallMethodIdObjArgs(self, &PyId___subclasscheck__, |
| 535 | subtype, NULL); |
| 536 | break; |
| 537 | case 1: // Nothing to do. |
| 538 | break; |
| 539 | default: |
| 540 | Py_UNREACHABLE(); |
| 541 | } |
| 542 | |
| 543 | end: |
| 544 | Py_XDECREF(impl); |
| 545 | Py_XDECREF(subclass); |
| 546 | return result; |
| 547 | } |
| 548 | |
| 549 | |
| 550 | // Return -1 when exception occured. |
| 551 | // Return 1 when result is set. |
| 552 | // Return 0 otherwise. |
| 553 | static int subclasscheck_check_registry(_abc_data *impl, PyObject *subclass, |
| 554 | PyObject **result); |
| 555 | |
| 556 | /*[clinic input] |
| 557 | _abc._abc_subclasscheck |
| 558 | |
| 559 | self: object |
| 560 | subclass: object |
| 561 | / |
| 562 | |
| 563 | Internal ABC helper for subclasss checks. Should be never used outside abc module. |
| 564 | [clinic start generated code]*/ |
| 565 | |
| 566 | static PyObject * |
| 567 | _abc__abc_subclasscheck_impl(PyObject *module, PyObject *self, |
| 568 | PyObject *subclass) |
| 569 | /*[clinic end generated code: output=b56c9e4a530e3894 input=1d947243409d10b8]*/ |
| 570 | { |
jab | 40472dd | 2018-03-23 00:26:06 +1300 | [diff] [blame] | 571 | if (!PyType_Check(subclass)) { |
| 572 | PyErr_SetString(PyExc_TypeError, "issubclass() arg 1 must be a class"); |
| 573 | return NULL; |
| 574 | } |
| 575 | |
INADA Naoki | f757b72 | 2018-03-22 21:52:42 +0900 | [diff] [blame] | 576 | PyObject *ok, *subclasses = NULL, *result = NULL; |
Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 577 | Py_ssize_t pos; |
| 578 | int incache; |
| 579 | _abc_data *impl = _get_impl(self); |
| 580 | if (impl == NULL) { |
| 581 | return NULL; |
| 582 | } |
| 583 | |
| 584 | /* 1. Check cache. */ |
| 585 | incache = _in_weak_set(impl->_abc_cache, subclass); |
| 586 | if (incache < 0) { |
| 587 | goto end; |
| 588 | } |
| 589 | if (incache > 0) { |
| 590 | result = Py_True; |
| 591 | goto end; |
| 592 | } |
| 593 | |
| 594 | /* 2. Check negative cache; may have to invalidate. */ |
| 595 | if (impl->_abc_negative_cache_version < abc_invalidation_counter) { |
| 596 | /* Invalidate the negative cache. */ |
| 597 | if (impl->_abc_negative_cache != NULL && |
| 598 | PySet_Clear(impl->_abc_negative_cache) < 0) |
| 599 | { |
| 600 | goto end; |
| 601 | } |
| 602 | impl->_abc_negative_cache_version = abc_invalidation_counter; |
| 603 | } |
| 604 | else { |
| 605 | incache = _in_weak_set(impl->_abc_negative_cache, subclass); |
| 606 | if (incache < 0) { |
| 607 | goto end; |
| 608 | } |
| 609 | if (incache > 0) { |
| 610 | result = Py_False; |
| 611 | goto end; |
| 612 | } |
| 613 | } |
| 614 | |
| 615 | /* 3. Check the subclass hook. */ |
| 616 | ok = _PyObject_CallMethodIdObjArgs((PyObject *)self, &PyId___subclasshook__, |
| 617 | subclass, NULL); |
| 618 | if (ok == NULL) { |
| 619 | goto end; |
| 620 | } |
| 621 | if (ok == Py_True) { |
| 622 | Py_DECREF(ok); |
| 623 | if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) { |
| 624 | goto end; |
| 625 | } |
| 626 | result = Py_True; |
| 627 | goto end; |
| 628 | } |
| 629 | if (ok == Py_False) { |
| 630 | Py_DECREF(ok); |
| 631 | if (_add_to_weak_set(&impl->_abc_negative_cache, subclass) < 0) { |
| 632 | goto end; |
| 633 | } |
| 634 | result = Py_False; |
| 635 | goto end; |
| 636 | } |
| 637 | if (ok != Py_NotImplemented) { |
| 638 | Py_DECREF(ok); |
| 639 | PyErr_SetString(PyExc_AssertionError, "__subclasshook__ must return either" |
| 640 | " False, True, or NotImplemented"); |
| 641 | goto end; |
| 642 | } |
| 643 | Py_DECREF(ok); |
| 644 | |
INADA Naoki | f757b72 | 2018-03-22 21:52:42 +0900 | [diff] [blame] | 645 | /* 4. Check if it's a direct subclass. */ |
| 646 | PyObject *mro = ((PyTypeObject *)subclass)->tp_mro; |
| 647 | assert(PyTuple_Check(mro)); |
| 648 | for (pos = 0; pos < PyTuple_GET_SIZE(mro); pos++) { |
| 649 | PyObject *mro_item = PyTuple_GET_ITEM(mro, pos); |
INADA Naoki | c65bf3f | 2018-03-23 18:19:34 +0900 | [diff] [blame] | 650 | assert(mro_item != NULL); |
INADA Naoki | f757b72 | 2018-03-22 21:52:42 +0900 | [diff] [blame] | 651 | if ((PyObject *)self == mro_item) { |
| 652 | if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) { |
Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 653 | goto end; |
| 654 | } |
INADA Naoki | f757b72 | 2018-03-22 21:52:42 +0900 | [diff] [blame] | 655 | result = Py_True; |
| 656 | goto end; |
Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 657 | } |
| 658 | } |
| 659 | |
| 660 | /* 5. Check if it's a subclass of a registered class (recursive). */ |
| 661 | if (subclasscheck_check_registry(impl, subclass, &result)) { |
| 662 | // Exception occured or result is set. |
| 663 | goto end; |
| 664 | } |
| 665 | |
| 666 | /* 6. Check if it's a subclass of a subclass (recursive). */ |
| 667 | subclasses = PyObject_CallMethod(self, "__subclasses__", NULL); |
Alexey Izbyshev | cdbf50c | 2018-08-20 23:04:19 +0300 | [diff] [blame] | 668 | if (subclasses == NULL) { |
| 669 | goto end; |
| 670 | } |
Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 671 | if (!PyList_Check(subclasses)) { |
| 672 | PyErr_SetString(PyExc_TypeError, "__subclasses__() must return a list"); |
| 673 | goto end; |
| 674 | } |
| 675 | for (pos = 0; pos < PyList_GET_SIZE(subclasses); pos++) { |
| 676 | PyObject *scls = PyList_GET_ITEM(subclasses, pos); |
| 677 | Py_INCREF(scls); |
| 678 | int r = PyObject_IsSubclass(subclass, scls); |
| 679 | Py_DECREF(scls); |
| 680 | if (r > 0) { |
| 681 | if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) { |
| 682 | goto end; |
| 683 | } |
| 684 | result = Py_True; |
| 685 | goto end; |
| 686 | } |
| 687 | if (r < 0) { |
| 688 | goto end; |
| 689 | } |
| 690 | } |
| 691 | |
| 692 | /* No dice; update negative cache. */ |
| 693 | if (_add_to_weak_set(&impl->_abc_negative_cache, subclass) < 0) { |
| 694 | goto end; |
| 695 | } |
| 696 | result = Py_False; |
| 697 | |
| 698 | end: |
INADA Naoki | fc7df0e | 2018-03-07 16:27:01 +0900 | [diff] [blame] | 699 | Py_DECREF(impl); |
Ivan Levkivskyi | 03e3c34 | 2018-02-18 12:41:58 +0000 | [diff] [blame] | 700 | Py_XDECREF(subclasses); |
| 701 | Py_XINCREF(result); |
| 702 | return result; |
| 703 | } |
| 704 | |
| 705 | |
| 706 | static int |
| 707 | subclasscheck_check_registry(_abc_data *impl, PyObject *subclass, |
| 708 | PyObject **result) |
| 709 | { |
| 710 | // Fast path: check subclass is in weakref directly. |
| 711 | int ret = _in_weak_set(impl->_abc_registry, subclass); |
| 712 | if (ret < 0) { |
| 713 | *result = NULL; |
| 714 | return -1; |
| 715 | } |
| 716 | if (ret > 0) { |
| 717 | *result = Py_True; |
| 718 | return 1; |
| 719 | } |
| 720 | |
| 721 | if (impl->_abc_registry == NULL) { |
| 722 | return 0; |
| 723 | } |
| 724 | Py_ssize_t registry_size = PySet_Size(impl->_abc_registry); |
| 725 | if (registry_size == 0) { |
| 726 | return 0; |
| 727 | } |
| 728 | // Weakref callback may remove entry from set. |
| 729 | // So we take snapshot of registry first. |
| 730 | PyObject **copy = PyMem_Malloc(sizeof(PyObject*) * registry_size); |
| 731 | PyObject *key; |
| 732 | Py_ssize_t pos = 0; |
| 733 | Py_hash_t hash; |
| 734 | Py_ssize_t i = 0; |
| 735 | |
| 736 | while (_PySet_NextEntry(impl->_abc_registry, &pos, &key, &hash)) { |
| 737 | Py_INCREF(key); |
| 738 | copy[i++] = key; |
| 739 | } |
| 740 | assert(i == registry_size); |
| 741 | |
| 742 | for (i = 0; i < registry_size; i++) { |
| 743 | PyObject *rkey = PyWeakref_GetObject(copy[i]); |
| 744 | if (rkey == NULL) { |
| 745 | // Someone inject non-weakref type in the registry. |
| 746 | ret = -1; |
| 747 | break; |
| 748 | } |
| 749 | if (rkey == Py_None) { |
| 750 | continue; |
| 751 | } |
| 752 | Py_INCREF(rkey); |
| 753 | int r = PyObject_IsSubclass(subclass, rkey); |
| 754 | Py_DECREF(rkey); |
| 755 | if (r < 0) { |
| 756 | ret = -1; |
| 757 | break; |
| 758 | } |
| 759 | if (r > 0) { |
| 760 | if (_add_to_weak_set(&impl->_abc_cache, subclass) < 0) { |
| 761 | ret = -1; |
| 762 | break; |
| 763 | } |
| 764 | *result = Py_True; |
| 765 | ret = 1; |
| 766 | break; |
| 767 | } |
| 768 | } |
| 769 | |
| 770 | for (i = 0; i < registry_size; i++) { |
| 771 | Py_DECREF(copy[i]); |
| 772 | } |
| 773 | PyMem_Free(copy); |
| 774 | return ret; |
| 775 | } |
| 776 | |
| 777 | /*[clinic input] |
| 778 | _abc.get_cache_token |
| 779 | |
| 780 | Returns the current ABC cache token. |
| 781 | |
| 782 | The token is an opaque object (supporting equality testing) identifying the |
| 783 | current version of the ABC cache for virtual subclasses. The token changes |
| 784 | with every call to register() on any ABC. |
| 785 | [clinic start generated code]*/ |
| 786 | |
| 787 | static PyObject * |
| 788 | _abc_get_cache_token_impl(PyObject *module) |
| 789 | /*[clinic end generated code: output=c7d87841e033dacc input=70413d1c423ad9f9]*/ |
| 790 | { |
| 791 | return PyLong_FromUnsignedLongLong(abc_invalidation_counter); |
| 792 | } |
| 793 | |
| 794 | static struct PyMethodDef module_functions[] = { |
| 795 | _ABC_GET_CACHE_TOKEN_METHODDEF |
| 796 | _ABC__ABC_INIT_METHODDEF |
| 797 | _ABC__RESET_REGISTRY_METHODDEF |
| 798 | _ABC__RESET_CACHES_METHODDEF |
| 799 | _ABC__GET_DUMP_METHODDEF |
| 800 | _ABC__ABC_REGISTER_METHODDEF |
| 801 | _ABC__ABC_INSTANCECHECK_METHODDEF |
| 802 | _ABC__ABC_SUBCLASSCHECK_METHODDEF |
| 803 | {NULL, NULL} /* sentinel */ |
| 804 | }; |
| 805 | |
| 806 | static struct PyModuleDef _abcmodule = { |
| 807 | PyModuleDef_HEAD_INIT, |
| 808 | "_abc", |
| 809 | _abc__doc__, |
| 810 | -1, |
| 811 | module_functions, |
| 812 | NULL, |
| 813 | NULL, |
| 814 | NULL, |
| 815 | NULL |
| 816 | }; |
| 817 | |
| 818 | |
| 819 | PyMODINIT_FUNC |
| 820 | PyInit__abc(void) |
| 821 | { |
| 822 | if (PyType_Ready(&_abc_data_type) < 0) { |
| 823 | return NULL; |
| 824 | } |
| 825 | _abc_data_type.tp_doc = abc_data_doc; |
| 826 | |
| 827 | return PyModule_Create(&_abcmodule); |
| 828 | } |