1 | #include "Python.h" |
2 | #include "pycore_object.h" // _PyObject_GET_WEAKREFS_LISTPTR() |
3 | #include "structmember.h" // PyMemberDef |
4 | |
5 | |
6 | #define GET_WEAKREFS_LISTPTR(o) \ |
7 | ((PyWeakReference **) _PyObject_GET_WEAKREFS_LISTPTR(o)) |
8 | |
9 | |
10 | Py_ssize_t |
11 | _PyWeakref_GetWeakrefCount(PyWeakReference *head) |
12 | { |
13 | Py_ssize_t count = 0; |
14 | |
15 | while (head != NULL) { |
16 | ++count; |
17 | head = head->wr_next; |
18 | } |
19 | return count; |
20 | } |
21 | |
22 | |
23 | static void |
24 | init_weakref(PyWeakReference *self, PyObject *ob, PyObject *callback) |
25 | { |
26 | self->hash = -1; |
27 | self->wr_object = ob; |
28 | self->wr_prev = NULL; |
29 | self->wr_next = NULL; |
30 | Py_XINCREF(callback); |
31 | self->wr_callback = callback; |
32 | } |
33 | |
34 | static PyWeakReference * |
35 | new_weakref(PyObject *ob, PyObject *callback) |
36 | { |
37 | PyWeakReference *result; |
38 | |
39 | result = PyObject_GC_New(PyWeakReference, &_PyWeakref_RefType); |
40 | if (result) { |
41 | init_weakref(result, ob, callback); |
42 | PyObject_GC_Track(result); |
43 | } |
44 | return result; |
45 | } |
46 | |
47 | |
48 | /* This function clears the passed-in reference and removes it from the |
49 | * list of weak references for the referent. This is the only code that |
50 | * removes an item from the doubly-linked list of weak references for an |
51 | * object; it is also responsible for clearing the callback slot. |
52 | */ |
53 | static void |
54 | clear_weakref(PyWeakReference *self) |
55 | { |
56 | PyObject *callback = self->wr_callback; |
57 | |
58 | if (self->wr_object != Py_None) { |
59 | PyWeakReference **list = GET_WEAKREFS_LISTPTR(self->wr_object); |
60 | |
61 | if (*list == self) |
62 | /* If 'self' is the end of the list (and thus self->wr_next == NULL) |
63 | then the weakref list itself (and thus the value of *list) will |
64 | end up being set to NULL. */ |
65 | *list = self->wr_next; |
66 | self->wr_object = Py_None; |
67 | if (self->wr_prev != NULL) |
68 | self->wr_prev->wr_next = self->wr_next; |
69 | if (self->wr_next != NULL) |
70 | self->wr_next->wr_prev = self->wr_prev; |
71 | self->wr_prev = NULL; |
72 | self->wr_next = NULL; |
73 | } |
74 | if (callback != NULL) { |
75 | Py_DECREF(callback); |
76 | self->wr_callback = NULL; |
77 | } |
78 | } |
79 | |
80 | /* Cyclic gc uses this to *just* clear the passed-in reference, leaving |
81 | * the callback intact and uncalled. It must be possible to call self's |
82 | * tp_dealloc() after calling this, so self has to be left in a sane enough |
83 | * state for that to work. We expect tp_dealloc to decref the callback |
84 | * then. The reason for not letting clear_weakref() decref the callback |
85 | * right now is that if the callback goes away, that may in turn trigger |
86 | * another callback (if a weak reference to the callback exists) -- running |
87 | * arbitrary Python code in the middle of gc is a disaster. The convolution |
88 | * here allows gc to delay triggering such callbacks until the world is in |
89 | * a sane state again. |
90 | */ |
91 | void |
92 | _PyWeakref_ClearRef(PyWeakReference *self) |
93 | { |
94 | PyObject *callback; |
95 | |
96 | assert(self != NULL); |
97 | assert(PyWeakref_Check(self)); |
98 | /* Preserve and restore the callback around clear_weakref. */ |
99 | callback = self->wr_callback; |
100 | self->wr_callback = NULL; |
101 | clear_weakref(self); |
102 | self->wr_callback = callback; |
103 | } |
104 | |
105 | static void |
106 | weakref_dealloc(PyObject *self) |
107 | { |
108 | PyObject_GC_UnTrack(self); |
109 | clear_weakref((PyWeakReference *) self); |
110 | Py_TYPE(self)->tp_free(self); |
111 | } |
112 | |
113 | |
114 | static int |
115 | gc_traverse(PyWeakReference *self, visitproc visit, void *arg) |
116 | { |
117 | Py_VISIT(self->wr_callback); |
118 | return 0; |
119 | } |
120 | |
121 | |
122 | static int |
123 | gc_clear(PyWeakReference *self) |
124 | { |
125 | clear_weakref(self); |
126 | return 0; |
127 | } |
128 | |
129 | |
130 | static PyObject * |
131 | weakref_call(PyWeakReference *self, PyObject *args, PyObject *kw) |
132 | { |
133 | static char *kwlist[] = {NULL}; |
134 | |
135 | if (PyArg_ParseTupleAndKeywords(args, kw, ":__call__" , kwlist)) { |
136 | PyObject *object = PyWeakref_GET_OBJECT(self); |
137 | Py_INCREF(object); |
138 | return (object); |
139 | } |
140 | return NULL; |
141 | } |
142 | |
143 | |
144 | static Py_hash_t |
145 | weakref_hash(PyWeakReference *self) |
146 | { |
147 | if (self->hash != -1) |
148 | return self->hash; |
149 | PyObject* obj = PyWeakref_GET_OBJECT(self); |
150 | if (obj == Py_None) { |
151 | PyErr_SetString(PyExc_TypeError, "weak object has gone away" ); |
152 | return -1; |
153 | } |
154 | Py_INCREF(obj); |
155 | self->hash = PyObject_Hash(obj); |
156 | Py_DECREF(obj); |
157 | return self->hash; |
158 | } |
159 | |
160 | |
161 | static PyObject * |
162 | weakref_repr(PyWeakReference *self) |
163 | { |
164 | PyObject *name, *repr; |
165 | _Py_IDENTIFIER(__name__); |
166 | PyObject* obj = PyWeakref_GET_OBJECT(self); |
167 | |
168 | if (obj == Py_None) { |
169 | return PyUnicode_FromFormat("<weakref at %p; dead>" , self); |
170 | } |
171 | |
172 | Py_INCREF(obj); |
173 | if (_PyObject_LookupAttrId(obj, &PyId___name__, &name) < 0) { |
174 | Py_DECREF(obj); |
175 | return NULL; |
176 | } |
177 | if (name == NULL || !PyUnicode_Check(name)) { |
178 | repr = PyUnicode_FromFormat( |
179 | "<weakref at %p; to '%s' at %p>" , |
180 | self, |
181 | Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name, |
182 | obj); |
183 | } |
184 | else { |
185 | repr = PyUnicode_FromFormat( |
186 | "<weakref at %p; to '%s' at %p (%U)>" , |
187 | self, |
188 | Py_TYPE(PyWeakref_GET_OBJECT(self))->tp_name, |
189 | obj, |
190 | name); |
191 | } |
192 | Py_DECREF(obj); |
193 | Py_XDECREF(name); |
194 | return repr; |
195 | } |
196 | |
197 | /* Weak references only support equality, not ordering. Two weak references |
198 | are equal if the underlying objects are equal. If the underlying object has |
199 | gone away, they are equal if they are identical. */ |
200 | |
201 | static PyObject * |
202 | weakref_richcompare(PyWeakReference* self, PyWeakReference* other, int op) |
203 | { |
204 | if ((op != Py_EQ && op != Py_NE) || |
205 | !PyWeakref_Check(self) || |
206 | !PyWeakref_Check(other)) { |
207 | Py_RETURN_NOTIMPLEMENTED; |
208 | } |
209 | if (PyWeakref_GET_OBJECT(self) == Py_None |
210 | || PyWeakref_GET_OBJECT(other) == Py_None) { |
211 | int res = (self == other); |
212 | if (op == Py_NE) |
213 | res = !res; |
214 | if (res) |
215 | Py_RETURN_TRUE; |
216 | else |
217 | Py_RETURN_FALSE; |
218 | } |
219 | PyObject* obj = PyWeakref_GET_OBJECT(self); |
220 | PyObject* other_obj = PyWeakref_GET_OBJECT(other); |
221 | Py_INCREF(obj); |
222 | Py_INCREF(other_obj); |
223 | PyObject* res = PyObject_RichCompare(obj, other_obj, op); |
224 | Py_DECREF(obj); |
225 | Py_DECREF(other_obj); |
226 | return res; |
227 | } |
228 | |
229 | /* Given the head of an object's list of weak references, extract the |
230 | * two callback-less refs (ref and proxy). Used to determine if the |
231 | * shared references exist and to determine the back link for newly |
232 | * inserted references. |
233 | */ |
234 | static void |
235 | get_basic_refs(PyWeakReference *head, |
236 | PyWeakReference **refp, PyWeakReference **proxyp) |
237 | { |
238 | *refp = NULL; |
239 | *proxyp = NULL; |
240 | |
241 | if (head != NULL && head->wr_callback == NULL) { |
242 | /* We need to be careful that the "basic refs" aren't |
243 | subclasses of the main types. That complicates this a |
244 | little. */ |
245 | if (PyWeakref_CheckRefExact(head)) { |
246 | *refp = head; |
247 | head = head->wr_next; |
248 | } |
249 | if (head != NULL |
250 | && head->wr_callback == NULL |
251 | && PyWeakref_CheckProxy(head)) { |
252 | *proxyp = head; |
253 | /* head = head->wr_next; */ |
254 | } |
255 | } |
256 | } |
257 | |
258 | /* Insert 'newref' in the list after 'prev'. Both must be non-NULL. */ |
259 | static void |
260 | insert_after(PyWeakReference *newref, PyWeakReference *prev) |
261 | { |
262 | newref->wr_prev = prev; |
263 | newref->wr_next = prev->wr_next; |
264 | if (prev->wr_next != NULL) |
265 | prev->wr_next->wr_prev = newref; |
266 | prev->wr_next = newref; |
267 | } |
268 | |
269 | /* Insert 'newref' at the head of the list; 'list' points to the variable |
270 | * that stores the head. |
271 | */ |
272 | static void |
273 | insert_head(PyWeakReference *newref, PyWeakReference **list) |
274 | { |
275 | PyWeakReference *next = *list; |
276 | |
277 | newref->wr_prev = NULL; |
278 | newref->wr_next = next; |
279 | if (next != NULL) |
280 | next->wr_prev = newref; |
281 | *list = newref; |
282 | } |
283 | |
284 | static int |
285 | parse_weakref_init_args(const char *funcname, PyObject *args, PyObject *kwargs, |
286 | PyObject **obp, PyObject **callbackp) |
287 | { |
288 | return PyArg_UnpackTuple(args, funcname, 1, 2, obp, callbackp); |
289 | } |
290 | |
291 | static PyObject * |
292 | weakref___new__(PyTypeObject *type, PyObject *args, PyObject *kwargs) |
293 | { |
294 | PyWeakReference *self = NULL; |
295 | PyObject *ob, *callback = NULL; |
296 | |
297 | if (parse_weakref_init_args("__new__" , args, kwargs, &ob, &callback)) { |
298 | PyWeakReference *ref, *proxy; |
299 | PyWeakReference **list; |
300 | |
301 | if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) { |
302 | PyErr_Format(PyExc_TypeError, |
303 | "cannot create weak reference to '%s' object" , |
304 | Py_TYPE(ob)->tp_name); |
305 | return NULL; |
306 | } |
307 | if (callback == Py_None) |
308 | callback = NULL; |
309 | list = GET_WEAKREFS_LISTPTR(ob); |
310 | get_basic_refs(*list, &ref, &proxy); |
311 | if (callback == NULL && type == &_PyWeakref_RefType) { |
312 | if (ref != NULL) { |
313 | /* We can re-use an existing reference. */ |
314 | Py_INCREF(ref); |
315 | return (PyObject *)ref; |
316 | } |
317 | } |
318 | /* We have to create a new reference. */ |
319 | /* Note: the tp_alloc() can trigger cyclic GC, so the weakref |
320 | list on ob can be mutated. This means that the ref and |
321 | proxy pointers we got back earlier may have been collected, |
322 | so we need to compute these values again before we use |
323 | them. */ |
324 | self = (PyWeakReference *) (type->tp_alloc(type, 0)); |
325 | if (self != NULL) { |
326 | init_weakref(self, ob, callback); |
327 | if (callback == NULL && type == &_PyWeakref_RefType) { |
328 | insert_head(self, list); |
329 | } |
330 | else { |
331 | PyWeakReference *prev; |
332 | |
333 | get_basic_refs(*list, &ref, &proxy); |
334 | prev = (proxy == NULL) ? ref : proxy; |
335 | if (prev == NULL) |
336 | insert_head(self, list); |
337 | else |
338 | insert_after(self, prev); |
339 | } |
340 | } |
341 | } |
342 | return (PyObject *)self; |
343 | } |
344 | |
345 | static int |
346 | weakref___init__(PyObject *self, PyObject *args, PyObject *kwargs) |
347 | { |
348 | PyObject *tmp; |
349 | |
350 | if (!_PyArg_NoKeywords("ref" , kwargs)) |
351 | return -1; |
352 | |
353 | if (parse_weakref_init_args("__init__" , args, kwargs, &tmp, &tmp)) |
354 | return 0; |
355 | else |
356 | return -1; |
357 | } |
358 | |
359 | |
360 | static PyMemberDef weakref_members[] = { |
361 | {"__callback__" , T_OBJECT, offsetof(PyWeakReference, wr_callback), READONLY}, |
362 | {NULL} /* Sentinel */ |
363 | }; |
364 | |
365 | static PyMethodDef weakref_methods[] = { |
366 | {"__class_getitem__" , (PyCFunction)Py_GenericAlias, |
367 | METH_O|METH_CLASS, PyDoc_STR("See PEP 585" )}, |
368 | {NULL} /* Sentinel */ |
369 | }; |
370 | |
371 | PyTypeObject |
372 | _PyWeakref_RefType = { |
373 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
374 | "weakref" , |
375 | sizeof(PyWeakReference), |
376 | 0, |
377 | weakref_dealloc, /*tp_dealloc*/ |
378 | 0, /*tp_vectorcall_offset*/ |
379 | 0, /*tp_getattr*/ |
380 | 0, /*tp_setattr*/ |
381 | 0, /*tp_as_async*/ |
382 | (reprfunc)weakref_repr, /*tp_repr*/ |
383 | 0, /*tp_as_number*/ |
384 | 0, /*tp_as_sequence*/ |
385 | 0, /*tp_as_mapping*/ |
386 | (hashfunc)weakref_hash, /*tp_hash*/ |
387 | (ternaryfunc)weakref_call, /*tp_call*/ |
388 | 0, /*tp_str*/ |
389 | 0, /*tp_getattro*/ |
390 | 0, /*tp_setattro*/ |
391 | 0, /*tp_as_buffer*/ |
392 | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
393 | | Py_TPFLAGS_BASETYPE, /*tp_flags*/ |
394 | 0, /*tp_doc*/ |
395 | (traverseproc)gc_traverse, /*tp_traverse*/ |
396 | (inquiry)gc_clear, /*tp_clear*/ |
397 | (richcmpfunc)weakref_richcompare, /*tp_richcompare*/ |
398 | 0, /*tp_weaklistoffset*/ |
399 | 0, /*tp_iter*/ |
400 | 0, /*tp_iternext*/ |
401 | weakref_methods, /*tp_methods*/ |
402 | weakref_members, /*tp_members*/ |
403 | 0, /*tp_getset*/ |
404 | 0, /*tp_base*/ |
405 | 0, /*tp_dict*/ |
406 | 0, /*tp_descr_get*/ |
407 | 0, /*tp_descr_set*/ |
408 | 0, /*tp_dictoffset*/ |
409 | weakref___init__, /*tp_init*/ |
410 | PyType_GenericAlloc, /*tp_alloc*/ |
411 | weakref___new__, /*tp_new*/ |
412 | PyObject_GC_Del, /*tp_free*/ |
413 | }; |
414 | |
415 | |
416 | static int |
417 | proxy_checkref(PyWeakReference *proxy) |
418 | { |
419 | if (PyWeakref_GET_OBJECT(proxy) == Py_None) { |
420 | PyErr_SetString(PyExc_ReferenceError, |
421 | "weakly-referenced object no longer exists" ); |
422 | return 0; |
423 | } |
424 | return 1; |
425 | } |
426 | |
427 | |
428 | /* If a parameter is a proxy, check that it is still "live" and wrap it, |
429 | * replacing the original value with the raw object. Raises ReferenceError |
430 | * if the param is a dead proxy. |
431 | */ |
432 | #define UNWRAP(o) \ |
433 | if (PyWeakref_CheckProxy(o)) { \ |
434 | if (!proxy_checkref((PyWeakReference *)o)) \ |
435 | return NULL; \ |
436 | o = PyWeakref_GET_OBJECT(o); \ |
437 | } |
438 | |
439 | #define WRAP_UNARY(method, generic) \ |
440 | static PyObject * \ |
441 | method(PyObject *proxy) { \ |
442 | UNWRAP(proxy); \ |
443 | Py_INCREF(proxy); \ |
444 | PyObject* res = generic(proxy); \ |
445 | Py_DECREF(proxy); \ |
446 | return res; \ |
447 | } |
448 | |
449 | #define WRAP_BINARY(method, generic) \ |
450 | static PyObject * \ |
451 | method(PyObject *x, PyObject *y) { \ |
452 | UNWRAP(x); \ |
453 | UNWRAP(y); \ |
454 | Py_INCREF(x); \ |
455 | Py_INCREF(y); \ |
456 | PyObject* res = generic(x, y); \ |
457 | Py_DECREF(x); \ |
458 | Py_DECREF(y); \ |
459 | return res; \ |
460 | } |
461 | |
462 | /* Note that the third arg needs to be checked for NULL since the tp_call |
463 | * slot can receive NULL for this arg. |
464 | */ |
465 | #define WRAP_TERNARY(method, generic) \ |
466 | static PyObject * \ |
467 | method(PyObject *proxy, PyObject *v, PyObject *w) { \ |
468 | UNWRAP(proxy); \ |
469 | UNWRAP(v); \ |
470 | if (w != NULL) \ |
471 | UNWRAP(w); \ |
472 | Py_INCREF(proxy); \ |
473 | Py_INCREF(v); \ |
474 | Py_XINCREF(w); \ |
475 | PyObject* res = generic(proxy, v, w); \ |
476 | Py_DECREF(proxy); \ |
477 | Py_DECREF(v); \ |
478 | Py_XDECREF(w); \ |
479 | return res; \ |
480 | } |
481 | |
482 | #define WRAP_METHOD(method, special) \ |
483 | static PyObject * \ |
484 | method(PyObject *proxy, PyObject *Py_UNUSED(ignored)) { \ |
485 | _Py_IDENTIFIER(special); \ |
486 | UNWRAP(proxy); \ |
487 | Py_INCREF(proxy); \ |
488 | PyObject* res = _PyObject_CallMethodIdNoArgs(proxy, &PyId_##special); \ |
489 | Py_DECREF(proxy); \ |
490 | return res; \ |
491 | } |
492 | |
493 | |
494 | /* direct slots */ |
495 | |
496 | WRAP_BINARY(proxy_getattr, PyObject_GetAttr) |
497 | WRAP_UNARY(proxy_str, PyObject_Str) |
498 | WRAP_TERNARY(proxy_call, PyObject_Call) |
499 | |
500 | static PyObject * |
501 | proxy_repr(PyWeakReference *proxy) |
502 | { |
503 | return PyUnicode_FromFormat( |
504 | "<weakproxy at %p to %s at %p>" , |
505 | proxy, |
506 | Py_TYPE(PyWeakref_GET_OBJECT(proxy))->tp_name, |
507 | PyWeakref_GET_OBJECT(proxy)); |
508 | } |
509 | |
510 | |
511 | static int |
512 | proxy_setattr(PyWeakReference *proxy, PyObject *name, PyObject *value) |
513 | { |
514 | if (!proxy_checkref(proxy)) |
515 | return -1; |
516 | PyObject *obj = PyWeakref_GET_OBJECT(proxy); |
517 | Py_INCREF(obj); |
518 | int res = PyObject_SetAttr(obj, name, value); |
519 | Py_DECREF(obj); |
520 | return res; |
521 | } |
522 | |
523 | static PyObject * |
524 | proxy_richcompare(PyObject *proxy, PyObject *v, int op) |
525 | { |
526 | UNWRAP(proxy); |
527 | UNWRAP(v); |
528 | return PyObject_RichCompare(proxy, v, op); |
529 | } |
530 | |
531 | /* number slots */ |
532 | WRAP_BINARY(proxy_add, PyNumber_Add) |
533 | WRAP_BINARY(proxy_sub, PyNumber_Subtract) |
534 | WRAP_BINARY(proxy_mul, PyNumber_Multiply) |
535 | WRAP_BINARY(proxy_floor_div, PyNumber_FloorDivide) |
536 | WRAP_BINARY(proxy_true_div, PyNumber_TrueDivide) |
537 | WRAP_BINARY(proxy_mod, PyNumber_Remainder) |
538 | WRAP_BINARY(proxy_divmod, PyNumber_Divmod) |
539 | WRAP_TERNARY(proxy_pow, PyNumber_Power) |
540 | WRAP_UNARY(proxy_neg, PyNumber_Negative) |
541 | WRAP_UNARY(proxy_pos, PyNumber_Positive) |
542 | WRAP_UNARY(proxy_abs, PyNumber_Absolute) |
543 | WRAP_UNARY(proxy_invert, PyNumber_Invert) |
544 | WRAP_BINARY(proxy_lshift, PyNumber_Lshift) |
545 | WRAP_BINARY(proxy_rshift, PyNumber_Rshift) |
546 | WRAP_BINARY(proxy_and, PyNumber_And) |
547 | WRAP_BINARY(proxy_xor, PyNumber_Xor) |
548 | WRAP_BINARY(proxy_or, PyNumber_Or) |
549 | WRAP_UNARY(proxy_int, PyNumber_Long) |
550 | WRAP_UNARY(proxy_float, PyNumber_Float) |
551 | WRAP_BINARY(proxy_iadd, PyNumber_InPlaceAdd) |
552 | WRAP_BINARY(proxy_isub, PyNumber_InPlaceSubtract) |
553 | WRAP_BINARY(proxy_imul, PyNumber_InPlaceMultiply) |
554 | WRAP_BINARY(proxy_ifloor_div, PyNumber_InPlaceFloorDivide) |
555 | WRAP_BINARY(proxy_itrue_div, PyNumber_InPlaceTrueDivide) |
556 | WRAP_BINARY(proxy_imod, PyNumber_InPlaceRemainder) |
557 | WRAP_TERNARY(proxy_ipow, PyNumber_InPlacePower) |
558 | WRAP_BINARY(proxy_ilshift, PyNumber_InPlaceLshift) |
559 | WRAP_BINARY(proxy_irshift, PyNumber_InPlaceRshift) |
560 | WRAP_BINARY(proxy_iand, PyNumber_InPlaceAnd) |
561 | WRAP_BINARY(proxy_ixor, PyNumber_InPlaceXor) |
562 | WRAP_BINARY(proxy_ior, PyNumber_InPlaceOr) |
563 | WRAP_UNARY(proxy_index, PyNumber_Index) |
564 | WRAP_BINARY(proxy_matmul, PyNumber_MatrixMultiply) |
565 | WRAP_BINARY(proxy_imatmul, PyNumber_InPlaceMatrixMultiply) |
566 | |
567 | static int |
568 | proxy_bool(PyWeakReference *proxy) |
569 | { |
570 | PyObject *o = PyWeakref_GET_OBJECT(proxy); |
571 | if (!proxy_checkref(proxy)) { |
572 | return -1; |
573 | } |
574 | Py_INCREF(o); |
575 | int res = PyObject_IsTrue(o); |
576 | Py_DECREF(o); |
577 | return res; |
578 | } |
579 | |
580 | static void |
581 | proxy_dealloc(PyWeakReference *self) |
582 | { |
583 | if (self->wr_callback != NULL) |
584 | PyObject_GC_UnTrack((PyObject *)self); |
585 | clear_weakref(self); |
586 | PyObject_GC_Del(self); |
587 | } |
588 | |
589 | /* sequence slots */ |
590 | |
591 | static int |
592 | proxy_contains(PyWeakReference *proxy, PyObject *value) |
593 | { |
594 | if (!proxy_checkref(proxy)) |
595 | return -1; |
596 | |
597 | PyObject *obj = PyWeakref_GET_OBJECT(proxy); |
598 | Py_INCREF(obj); |
599 | int res = PySequence_Contains(obj, value); |
600 | Py_DECREF(obj); |
601 | return res; |
602 | } |
603 | |
604 | /* mapping slots */ |
605 | |
606 | static Py_ssize_t |
607 | proxy_length(PyWeakReference *proxy) |
608 | { |
609 | if (!proxy_checkref(proxy)) |
610 | return -1; |
611 | |
612 | PyObject *obj = PyWeakref_GET_OBJECT(proxy); |
613 | Py_INCREF(obj); |
614 | Py_ssize_t res = PyObject_Length(obj); |
615 | Py_DECREF(obj); |
616 | return res; |
617 | } |
618 | |
619 | WRAP_BINARY(proxy_getitem, PyObject_GetItem) |
620 | |
621 | static int |
622 | proxy_setitem(PyWeakReference *proxy, PyObject *key, PyObject *value) |
623 | { |
624 | if (!proxy_checkref(proxy)) |
625 | return -1; |
626 | |
627 | PyObject *obj = PyWeakref_GET_OBJECT(proxy); |
628 | Py_INCREF(obj); |
629 | int res; |
630 | if (value == NULL) { |
631 | res = PyObject_DelItem(obj, key); |
632 | } else { |
633 | res = PyObject_SetItem(obj, key, value); |
634 | } |
635 | Py_DECREF(obj); |
636 | return res; |
637 | } |
638 | |
639 | /* iterator slots */ |
640 | |
641 | static PyObject * |
642 | proxy_iter(PyWeakReference *proxy) |
643 | { |
644 | if (!proxy_checkref(proxy)) |
645 | return NULL; |
646 | PyObject *obj = PyWeakref_GET_OBJECT(proxy); |
647 | Py_INCREF(obj); |
648 | PyObject* res = PyObject_GetIter(obj); |
649 | Py_DECREF(obj); |
650 | return res; |
651 | } |
652 | |
653 | static PyObject * |
654 | proxy_iternext(PyWeakReference *proxy) |
655 | { |
656 | if (!proxy_checkref(proxy)) |
657 | return NULL; |
658 | |
659 | PyObject *obj = PyWeakref_GET_OBJECT(proxy); |
660 | if (!PyIter_Check(obj)) { |
661 | PyErr_Format(PyExc_TypeError, |
662 | "Weakref proxy referenced a non-iterator '%.200s' object" , |
663 | Py_TYPE(obj)->tp_name); |
664 | return NULL; |
665 | } |
666 | Py_INCREF(obj); |
667 | PyObject* res = PyIter_Next(obj); |
668 | Py_DECREF(obj); |
669 | return res; |
670 | } |
671 | |
672 | |
673 | WRAP_METHOD(proxy_bytes, __bytes__) |
674 | WRAP_METHOD(proxy_reversed, __reversed__) |
675 | |
676 | |
677 | static PyMethodDef proxy_methods[] = { |
678 | {"__bytes__" , proxy_bytes, METH_NOARGS}, |
679 | {"__reversed__" , proxy_reversed, METH_NOARGS}, |
680 | {NULL, NULL} |
681 | }; |
682 | |
683 | |
684 | static PyNumberMethods proxy_as_number = { |
685 | proxy_add, /*nb_add*/ |
686 | proxy_sub, /*nb_subtract*/ |
687 | proxy_mul, /*nb_multiply*/ |
688 | proxy_mod, /*nb_remainder*/ |
689 | proxy_divmod, /*nb_divmod*/ |
690 | proxy_pow, /*nb_power*/ |
691 | proxy_neg, /*nb_negative*/ |
692 | proxy_pos, /*nb_positive*/ |
693 | proxy_abs, /*nb_absolute*/ |
694 | (inquiry)proxy_bool, /*nb_bool*/ |
695 | proxy_invert, /*nb_invert*/ |
696 | proxy_lshift, /*nb_lshift*/ |
697 | proxy_rshift, /*nb_rshift*/ |
698 | proxy_and, /*nb_and*/ |
699 | proxy_xor, /*nb_xor*/ |
700 | proxy_or, /*nb_or*/ |
701 | proxy_int, /*nb_int*/ |
702 | 0, /*nb_reserved*/ |
703 | proxy_float, /*nb_float*/ |
704 | proxy_iadd, /*nb_inplace_add*/ |
705 | proxy_isub, /*nb_inplace_subtract*/ |
706 | proxy_imul, /*nb_inplace_multiply*/ |
707 | proxy_imod, /*nb_inplace_remainder*/ |
708 | proxy_ipow, /*nb_inplace_power*/ |
709 | proxy_ilshift, /*nb_inplace_lshift*/ |
710 | proxy_irshift, /*nb_inplace_rshift*/ |
711 | proxy_iand, /*nb_inplace_and*/ |
712 | proxy_ixor, /*nb_inplace_xor*/ |
713 | proxy_ior, /*nb_inplace_or*/ |
714 | proxy_floor_div, /*nb_floor_divide*/ |
715 | proxy_true_div, /*nb_true_divide*/ |
716 | proxy_ifloor_div, /*nb_inplace_floor_divide*/ |
717 | proxy_itrue_div, /*nb_inplace_true_divide*/ |
718 | proxy_index, /*nb_index*/ |
719 | proxy_matmul, /*nb_matrix_multiply*/ |
720 | proxy_imatmul, /*nb_inplace_matrix_multiply*/ |
721 | }; |
722 | |
723 | static PySequenceMethods proxy_as_sequence = { |
724 | (lenfunc)proxy_length, /*sq_length*/ |
725 | 0, /*sq_concat*/ |
726 | 0, /*sq_repeat*/ |
727 | 0, /*sq_item*/ |
728 | 0, /*sq_slice*/ |
729 | 0, /*sq_ass_item*/ |
730 | 0, /*sq_ass_slice*/ |
731 | (objobjproc)proxy_contains, /* sq_contains */ |
732 | }; |
733 | |
734 | static PyMappingMethods proxy_as_mapping = { |
735 | (lenfunc)proxy_length, /*mp_length*/ |
736 | proxy_getitem, /*mp_subscript*/ |
737 | (objobjargproc)proxy_setitem, /*mp_ass_subscript*/ |
738 | }; |
739 | |
740 | |
741 | PyTypeObject |
742 | _PyWeakref_ProxyType = { |
743 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
744 | "weakproxy" , |
745 | sizeof(PyWeakReference), |
746 | 0, |
747 | /* methods */ |
748 | (destructor)proxy_dealloc, /* tp_dealloc */ |
749 | 0, /* tp_vectorcall_offset */ |
750 | 0, /* tp_getattr */ |
751 | 0, /* tp_setattr */ |
752 | 0, /* tp_as_async */ |
753 | (reprfunc)proxy_repr, /* tp_repr */ |
754 | &proxy_as_number, /* tp_as_number */ |
755 | &proxy_as_sequence, /* tp_as_sequence */ |
756 | &proxy_as_mapping, /* tp_as_mapping */ |
757 | // Notice that tp_hash is intentionally omitted as proxies are "mutable" (when the reference dies). |
758 | 0, /* tp_hash */ |
759 | 0, /* tp_call */ |
760 | proxy_str, /* tp_str */ |
761 | proxy_getattr, /* tp_getattro */ |
762 | (setattrofunc)proxy_setattr, /* tp_setattro */ |
763 | 0, /* tp_as_buffer */ |
764 | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */ |
765 | 0, /* tp_doc */ |
766 | (traverseproc)gc_traverse, /* tp_traverse */ |
767 | (inquiry)gc_clear, /* tp_clear */ |
768 | proxy_richcompare, /* tp_richcompare */ |
769 | 0, /* tp_weaklistoffset */ |
770 | (getiterfunc)proxy_iter, /* tp_iter */ |
771 | (iternextfunc)proxy_iternext, /* tp_iternext */ |
772 | proxy_methods, /* tp_methods */ |
773 | }; |
774 | |
775 | |
776 | PyTypeObject |
777 | _PyWeakref_CallableProxyType = { |
778 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
779 | "weakcallableproxy" , |
780 | sizeof(PyWeakReference), |
781 | 0, |
782 | /* methods */ |
783 | (destructor)proxy_dealloc, /* tp_dealloc */ |
784 | 0, /* tp_vectorcall_offset */ |
785 | 0, /* tp_getattr */ |
786 | 0, /* tp_setattr */ |
787 | 0, /* tp_as_async */ |
788 | (unaryfunc)proxy_repr, /* tp_repr */ |
789 | &proxy_as_number, /* tp_as_number */ |
790 | &proxy_as_sequence, /* tp_as_sequence */ |
791 | &proxy_as_mapping, /* tp_as_mapping */ |
792 | 0, /* tp_hash */ |
793 | proxy_call, /* tp_call */ |
794 | proxy_str, /* tp_str */ |
795 | proxy_getattr, /* tp_getattro */ |
796 | (setattrofunc)proxy_setattr, /* tp_setattro */ |
797 | 0, /* tp_as_buffer */ |
798 | Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */ |
799 | 0, /* tp_doc */ |
800 | (traverseproc)gc_traverse, /* tp_traverse */ |
801 | (inquiry)gc_clear, /* tp_clear */ |
802 | proxy_richcompare, /* tp_richcompare */ |
803 | 0, /* tp_weaklistoffset */ |
804 | (getiterfunc)proxy_iter, /* tp_iter */ |
805 | (iternextfunc)proxy_iternext, /* tp_iternext */ |
806 | }; |
807 | |
808 | |
809 | |
810 | PyObject * |
811 | PyWeakref_NewRef(PyObject *ob, PyObject *callback) |
812 | { |
813 | PyWeakReference *result = NULL; |
814 | PyWeakReference **list; |
815 | PyWeakReference *ref, *proxy; |
816 | |
817 | if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) { |
818 | PyErr_Format(PyExc_TypeError, |
819 | "cannot create weak reference to '%s' object" , |
820 | Py_TYPE(ob)->tp_name); |
821 | return NULL; |
822 | } |
823 | list = GET_WEAKREFS_LISTPTR(ob); |
824 | get_basic_refs(*list, &ref, &proxy); |
825 | if (callback == Py_None) |
826 | callback = NULL; |
827 | if (callback == NULL) |
828 | /* return existing weak reference if it exists */ |
829 | result = ref; |
830 | if (result != NULL) |
831 | Py_INCREF(result); |
832 | else { |
833 | /* Note: new_weakref() can trigger cyclic GC, so the weakref |
834 | list on ob can be mutated. This means that the ref and |
835 | proxy pointers we got back earlier may have been collected, |
836 | so we need to compute these values again before we use |
837 | them. */ |
838 | result = new_weakref(ob, callback); |
839 | if (result != NULL) { |
840 | get_basic_refs(*list, &ref, &proxy); |
841 | if (callback == NULL) { |
842 | if (ref == NULL) |
843 | insert_head(result, list); |
844 | else { |
845 | /* Someone else added a ref without a callback |
846 | during GC. Return that one instead of this one |
847 | to avoid violating the invariants of the list |
848 | of weakrefs for ob. */ |
849 | Py_DECREF(result); |
850 | Py_INCREF(ref); |
851 | result = ref; |
852 | } |
853 | } |
854 | else { |
855 | PyWeakReference *prev; |
856 | |
857 | prev = (proxy == NULL) ? ref : proxy; |
858 | if (prev == NULL) |
859 | insert_head(result, list); |
860 | else |
861 | insert_after(result, prev); |
862 | } |
863 | } |
864 | } |
865 | return (PyObject *) result; |
866 | } |
867 | |
868 | |
869 | PyObject * |
870 | PyWeakref_NewProxy(PyObject *ob, PyObject *callback) |
871 | { |
872 | PyWeakReference *result = NULL; |
873 | PyWeakReference **list; |
874 | PyWeakReference *ref, *proxy; |
875 | |
876 | if (!PyType_SUPPORTS_WEAKREFS(Py_TYPE(ob))) { |
877 | PyErr_Format(PyExc_TypeError, |
878 | "cannot create weak reference to '%s' object" , |
879 | Py_TYPE(ob)->tp_name); |
880 | return NULL; |
881 | } |
882 | list = GET_WEAKREFS_LISTPTR(ob); |
883 | get_basic_refs(*list, &ref, &proxy); |
884 | if (callback == Py_None) |
885 | callback = NULL; |
886 | if (callback == NULL) |
887 | /* attempt to return an existing weak reference if it exists */ |
888 | result = proxy; |
889 | if (result != NULL) |
890 | Py_INCREF(result); |
891 | else { |
892 | /* Note: new_weakref() can trigger cyclic GC, so the weakref |
893 | list on ob can be mutated. This means that the ref and |
894 | proxy pointers we got back earlier may have been collected, |
895 | so we need to compute these values again before we use |
896 | them. */ |
897 | result = new_weakref(ob, callback); |
898 | if (result != NULL) { |
899 | PyWeakReference *prev; |
900 | |
901 | if (PyCallable_Check(ob)) { |
902 | Py_SET_TYPE(result, &_PyWeakref_CallableProxyType); |
903 | } |
904 | else { |
905 | Py_SET_TYPE(result, &_PyWeakref_ProxyType); |
906 | } |
907 | get_basic_refs(*list, &ref, &proxy); |
908 | if (callback == NULL) { |
909 | if (proxy != NULL) { |
910 | /* Someone else added a proxy without a callback |
911 | during GC. Return that one instead of this one |
912 | to avoid violating the invariants of the list |
913 | of weakrefs for ob. */ |
914 | Py_DECREF(result); |
915 | result = proxy; |
916 | Py_INCREF(result); |
917 | goto skip_insert; |
918 | } |
919 | prev = ref; |
920 | } |
921 | else |
922 | prev = (proxy == NULL) ? ref : proxy; |
923 | |
924 | if (prev == NULL) |
925 | insert_head(result, list); |
926 | else |
927 | insert_after(result, prev); |
928 | skip_insert: |
929 | ; |
930 | } |
931 | } |
932 | return (PyObject *) result; |
933 | } |
934 | |
935 | |
936 | PyObject * |
937 | PyWeakref_GetObject(PyObject *ref) |
938 | { |
939 | if (ref == NULL || !PyWeakref_Check(ref)) { |
940 | PyErr_BadInternalCall(); |
941 | return NULL; |
942 | } |
943 | return PyWeakref_GET_OBJECT(ref); |
944 | } |
945 | |
946 | /* Note that there's an inlined copy-paste of handle_callback() in gcmodule.c's |
947 | * handle_weakrefs(). |
948 | */ |
949 | static void |
950 | handle_callback(PyWeakReference *ref, PyObject *callback) |
951 | { |
952 | PyObject *cbresult = PyObject_CallOneArg(callback, (PyObject *)ref); |
953 | |
954 | if (cbresult == NULL) |
955 | PyErr_WriteUnraisable(callback); |
956 | else |
957 | Py_DECREF(cbresult); |
958 | } |
959 | |
960 | /* This function is called by the tp_dealloc handler to clear weak references. |
961 | * |
962 | * This iterates through the weak references for 'object' and calls callbacks |
963 | * for those references which have one. It returns when all callbacks have |
964 | * been attempted. |
965 | */ |
966 | void |
967 | PyObject_ClearWeakRefs(PyObject *object) |
968 | { |
969 | PyWeakReference **list; |
970 | |
971 | if (object == NULL |
972 | || !PyType_SUPPORTS_WEAKREFS(Py_TYPE(object)) |
973 | || Py_REFCNT(object) != 0) |
974 | { |
975 | PyErr_BadInternalCall(); |
976 | return; |
977 | } |
978 | list = GET_WEAKREFS_LISTPTR(object); |
979 | /* Remove the callback-less basic and proxy references */ |
980 | if (*list != NULL && (*list)->wr_callback == NULL) { |
981 | clear_weakref(*list); |
982 | if (*list != NULL && (*list)->wr_callback == NULL) |
983 | clear_weakref(*list); |
984 | } |
985 | if (*list != NULL) { |
986 | PyWeakReference *current = *list; |
987 | Py_ssize_t count = _PyWeakref_GetWeakrefCount(current); |
988 | PyObject *err_type, *err_value, *err_tb; |
989 | |
990 | PyErr_Fetch(&err_type, &err_value, &err_tb); |
991 | if (count == 1) { |
992 | PyObject *callback = current->wr_callback; |
993 | |
994 | current->wr_callback = NULL; |
995 | clear_weakref(current); |
996 | if (callback != NULL) { |
997 | if (Py_REFCNT((PyObject *)current) > 0) { |
998 | handle_callback(current, callback); |
999 | } |
1000 | Py_DECREF(callback); |
1001 | } |
1002 | } |
1003 | else { |
1004 | PyObject *tuple; |
1005 | Py_ssize_t i = 0; |
1006 | |
1007 | tuple = PyTuple_New(count * 2); |
1008 | if (tuple == NULL) { |
1009 | _PyErr_ChainExceptions(err_type, err_value, err_tb); |
1010 | return; |
1011 | } |
1012 | |
1013 | for (i = 0; i < count; ++i) { |
1014 | PyWeakReference *next = current->wr_next; |
1015 | |
1016 | if (Py_REFCNT((PyObject *)current) > 0) { |
1017 | Py_INCREF(current); |
1018 | PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current); |
1019 | PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback); |
1020 | } |
1021 | else { |
1022 | Py_DECREF(current->wr_callback); |
1023 | } |
1024 | current->wr_callback = NULL; |
1025 | clear_weakref(current); |
1026 | current = next; |
1027 | } |
1028 | for (i = 0; i < count; ++i) { |
1029 | PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1); |
1030 | |
1031 | /* The tuple may have slots left to NULL */ |
1032 | if (callback != NULL) { |
1033 | PyObject *item = PyTuple_GET_ITEM(tuple, i * 2); |
1034 | handle_callback((PyWeakReference *)item, callback); |
1035 | } |
1036 | } |
1037 | Py_DECREF(tuple); |
1038 | } |
1039 | assert(!PyErr_Occurred()); |
1040 | PyErr_Restore(err_type, err_value, err_tb); |
1041 | } |
1042 | } |
1043 | |