1 /* Descriptors -- a new, flexible way to describe attributes */
2
3 #include "Python.h"
4 #include "structmember.h" /* Why is this not included in Python.h? */
5
6 static void
descr_dealloc(PyDescrObject * descr)7 descr_dealloc(PyDescrObject *descr)
8 {
9 _PyObject_GC_UNTRACK(descr);
10 Py_XDECREF(descr->d_type);
11 Py_XDECREF(descr->d_name);
12 PyObject_GC_Del(descr);
13 }
14
15 static char *
descr_name(PyDescrObject * descr)16 descr_name(PyDescrObject *descr)
17 {
18 if (descr->d_name != NULL && PyString_Check(descr->d_name))
19 return PyString_AS_STRING(descr->d_name);
20 else
21 return "?";
22 }
23
24 static PyObject *
descr_repr(PyDescrObject * descr,char * format)25 descr_repr(PyDescrObject *descr, char *format)
26 {
27 return PyString_FromFormat(format, descr_name(descr),
28 descr->d_type->tp_name);
29 }
30
31 static PyObject *
method_repr(PyMethodDescrObject * descr)32 method_repr(PyMethodDescrObject *descr)
33 {
34 return descr_repr((PyDescrObject *)descr,
35 "<method '%s' of '%s' objects>");
36 }
37
38 static PyObject *
member_repr(PyMemberDescrObject * descr)39 member_repr(PyMemberDescrObject *descr)
40 {
41 return descr_repr((PyDescrObject *)descr,
42 "<member '%s' of '%s' objects>");
43 }
44
45 static PyObject *
getset_repr(PyGetSetDescrObject * descr)46 getset_repr(PyGetSetDescrObject *descr)
47 {
48 return descr_repr((PyDescrObject *)descr,
49 "<attribute '%s' of '%s' objects>");
50 }
51
52 static PyObject *
wrapperdescr_repr(PyWrapperDescrObject * descr)53 wrapperdescr_repr(PyWrapperDescrObject *descr)
54 {
55 return descr_repr((PyDescrObject *)descr,
56 "<slot wrapper '%s' of '%s' objects>");
57 }
58
59 static int
descr_check(PyDescrObject * descr,PyObject * obj,PyObject ** pres)60 descr_check(PyDescrObject *descr, PyObject *obj, PyObject **pres)
61 {
62 if (obj == NULL) {
63 Py_INCREF(descr);
64 *pres = (PyObject *)descr;
65 return 1;
66 }
67 if (!PyObject_TypeCheck(obj, descr->d_type)) {
68 PyErr_Format(PyExc_TypeError,
69 "descriptor '%s' for '%s' objects "
70 "doesn't apply to '%s' object",
71 descr_name((PyDescrObject *)descr),
72 descr->d_type->tp_name,
73 obj->ob_type->tp_name);
74 *pres = NULL;
75 return 1;
76 }
77 return 0;
78 }
79
80 static PyObject *
classmethod_get(PyMethodDescrObject * descr,PyObject * obj,PyObject * type)81 classmethod_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
82 {
83 /* Ensure a valid type. Class methods ignore obj. */
84 if (type == NULL) {
85 if (obj != NULL)
86 type = (PyObject *)obj->ob_type;
87 else {
88 /* Wot - no type?! */
89 PyErr_Format(PyExc_TypeError,
90 "descriptor '%s' for type '%s' "
91 "needs either an object or a type",
92 descr_name((PyDescrObject *)descr),
93 descr->d_type->tp_name);
94 return NULL;
95 }
96 }
97 if (!PyType_Check(type)) {
98 PyErr_Format(PyExc_TypeError,
99 "descriptor '%s' for type '%s' "
100 "needs a type, not a '%s' as arg 2",
101 descr_name((PyDescrObject *)descr),
102 descr->d_type->tp_name,
103 type->ob_type->tp_name);
104 return NULL;
105 }
106 if (!PyType_IsSubtype((PyTypeObject *)type, descr->d_type)) {
107 PyErr_Format(PyExc_TypeError,
108 "descriptor '%s' for type '%s' "
109 "doesn't apply to type '%s'",
110 descr_name((PyDescrObject *)descr),
111 descr->d_type->tp_name,
112 ((PyTypeObject *)type)->tp_name);
113 return NULL;
114 }
115 return PyCFunction_New(descr->d_method, type);
116 }
117
118 static PyObject *
method_get(PyMethodDescrObject * descr,PyObject * obj,PyObject * type)119 method_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
120 {
121 PyObject *res;
122
123 if (descr_check((PyDescrObject *)descr, obj, &res))
124 return res;
125 return PyCFunction_New(descr->d_method, obj);
126 }
127
128 static PyObject *
member_get(PyMemberDescrObject * descr,PyObject * obj,PyObject * type)129 member_get(PyMemberDescrObject *descr, PyObject *obj, PyObject *type)
130 {
131 PyObject *res;
132
133 if (descr_check((PyDescrObject *)descr, obj, &res))
134 return res;
135 return PyMember_GetOne((char *)obj, descr->d_member);
136 }
137
138 static PyObject *
getset_get(PyGetSetDescrObject * descr,PyObject * obj,PyObject * type)139 getset_get(PyGetSetDescrObject *descr, PyObject *obj, PyObject *type)
140 {
141 PyObject *res;
142
143 if (descr_check((PyDescrObject *)descr, obj, &res))
144 return res;
145 if (descr->d_getset->get != NULL)
146 return descr->d_getset->get(obj, descr->d_getset->closure);
147 PyErr_Format(PyExc_AttributeError,
148 "attribute '%.300s' of '%.100s' objects is not readable",
149 descr_name((PyDescrObject *)descr),
150 descr->d_type->tp_name);
151 return NULL;
152 }
153
154 static PyObject *
wrapperdescr_get(PyWrapperDescrObject * descr,PyObject * obj,PyObject * type)155 wrapperdescr_get(PyWrapperDescrObject *descr, PyObject *obj, PyObject *type)
156 {
157 PyObject *res;
158
159 if (descr_check((PyDescrObject *)descr, obj, &res))
160 return res;
161 return PyWrapper_New((PyObject *)descr, obj);
162 }
163
164 static int
descr_setcheck(PyDescrObject * descr,PyObject * obj,PyObject * value,int * pres)165 descr_setcheck(PyDescrObject *descr, PyObject *obj, PyObject *value,
166 int *pres)
167 {
168 assert(obj != NULL);
169 if (!PyObject_TypeCheck(obj, descr->d_type)) {
170 PyErr_Format(PyExc_TypeError,
171 "descriptor '%.200s' for '%.100s' objects "
172 "doesn't apply to '%.100s' object",
173 descr_name(descr),
174 descr->d_type->tp_name,
175 obj->ob_type->tp_name);
176 *pres = -1;
177 return 1;
178 }
179 return 0;
180 }
181
182 static int
member_set(PyMemberDescrObject * descr,PyObject * obj,PyObject * value)183 member_set(PyMemberDescrObject *descr, PyObject *obj, PyObject *value)
184 {
185 int res;
186
187 if (descr_setcheck((PyDescrObject *)descr, obj, value, &res))
188 return res;
189 return PyMember_SetOne((char *)obj, descr->d_member, value);
190 }
191
192 static int
getset_set(PyGetSetDescrObject * descr,PyObject * obj,PyObject * value)193 getset_set(PyGetSetDescrObject *descr, PyObject *obj, PyObject *value)
194 {
195 int res;
196
197 if (descr_setcheck((PyDescrObject *)descr, obj, value, &res))
198 return res;
199 if (descr->d_getset->set != NULL)
200 return descr->d_getset->set(obj, value,
201 descr->d_getset->closure);
202 PyErr_Format(PyExc_AttributeError,
203 "attribute '%.300s' of '%.100s' objects is not writable",
204 descr_name((PyDescrObject *)descr),
205 descr->d_type->tp_name);
206 return -1;
207 }
208
209 static PyObject *
methoddescr_call(PyMethodDescrObject * descr,PyObject * args,PyObject * kwds)210 methoddescr_call(PyMethodDescrObject *descr, PyObject *args, PyObject *kwds)
211 {
212 Py_ssize_t argc;
213 PyObject *self, *func, *result;
214
215 /* Make sure that the first argument is acceptable as 'self' */
216 assert(PyTuple_Check(args));
217 argc = PyTuple_GET_SIZE(args);
218 if (argc < 1) {
219 PyErr_Format(PyExc_TypeError,
220 "descriptor '%.300s' of '%.100s' "
221 "object needs an argument",
222 descr_name((PyDescrObject *)descr),
223 descr->d_type->tp_name);
224 return NULL;
225 }
226 self = PyTuple_GET_ITEM(args, 0);
227 if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
228 (PyObject *)(descr->d_type))) {
229 PyErr_Format(PyExc_TypeError,
230 "descriptor '%.200s' "
231 "requires a '%.100s' object "
232 "but received a '%.100s'",
233 descr_name((PyDescrObject *)descr),
234 descr->d_type->tp_name,
235 self->ob_type->tp_name);
236 return NULL;
237 }
238
239 func = PyCFunction_New(descr->d_method, self);
240 if (func == NULL)
241 return NULL;
242 args = PyTuple_GetSlice(args, 1, argc);
243 if (args == NULL) {
244 Py_DECREF(func);
245 return NULL;
246 }
247 result = PyEval_CallObjectWithKeywords(func, args, kwds);
248 Py_DECREF(args);
249 Py_DECREF(func);
250 return result;
251 }
252
253 static PyObject *
classmethoddescr_call(PyMethodDescrObject * descr,PyObject * args,PyObject * kwds)254 classmethoddescr_call(PyMethodDescrObject *descr, PyObject *args,
255 PyObject *kwds)
256 {
257 PyObject *func, *result;
258
259 func = PyCFunction_New(descr->d_method, (PyObject *)descr->d_type);
260 if (func == NULL)
261 return NULL;
262
263 result = PyEval_CallObjectWithKeywords(func, args, kwds);
264 Py_DECREF(func);
265 return result;
266 }
267
268 static PyObject *
wrapperdescr_call(PyWrapperDescrObject * descr,PyObject * args,PyObject * kwds)269 wrapperdescr_call(PyWrapperDescrObject *descr, PyObject *args, PyObject *kwds)
270 {
271 Py_ssize_t argc;
272 PyObject *self, *func, *result;
273
274 /* Make sure that the first argument is acceptable as 'self' */
275 assert(PyTuple_Check(args));
276 argc = PyTuple_GET_SIZE(args);
277 if (argc < 1) {
278 PyErr_Format(PyExc_TypeError,
279 "descriptor '%.300s' of '%.100s' "
280 "object needs an argument",
281 descr_name((PyDescrObject *)descr),
282 descr->d_type->tp_name);
283 return NULL;
284 }
285 self = PyTuple_GET_ITEM(args, 0);
286 if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
287 (PyObject *)(descr->d_type))) {
288 PyErr_Format(PyExc_TypeError,
289 "descriptor '%.200s' "
290 "requires a '%.100s' object "
291 "but received a '%.100s'",
292 descr_name((PyDescrObject *)descr),
293 descr->d_type->tp_name,
294 self->ob_type->tp_name);
295 return NULL;
296 }
297
298 func = PyWrapper_New((PyObject *)descr, self);
299 if (func == NULL)
300 return NULL;
301 args = PyTuple_GetSlice(args, 1, argc);
302 if (args == NULL) {
303 Py_DECREF(func);
304 return NULL;
305 }
306 result = PyEval_CallObjectWithKeywords(func, args, kwds);
307 Py_DECREF(args);
308 Py_DECREF(func);
309 return result;
310 }
311
312 static PyObject *
method_get_doc(PyMethodDescrObject * descr,void * closure)313 method_get_doc(PyMethodDescrObject *descr, void *closure)
314 {
315 if (descr->d_method->ml_doc == NULL) {
316 Py_INCREF(Py_None);
317 return Py_None;
318 }
319 return PyString_FromString(descr->d_method->ml_doc);
320 }
321
322 static PyMemberDef descr_members[] = {
323 {"__objclass__", T_OBJECT, offsetof(PyDescrObject, d_type), READONLY},
324 {"__name__", T_OBJECT, offsetof(PyDescrObject, d_name), READONLY},
325 {0}
326 };
327
328 static PyGetSetDef method_getset[] = {
329 {"__doc__", (getter)method_get_doc},
330 {0}
331 };
332
333 static PyObject *
member_get_doc(PyMemberDescrObject * descr,void * closure)334 member_get_doc(PyMemberDescrObject *descr, void *closure)
335 {
336 if (descr->d_member->doc == NULL) {
337 Py_INCREF(Py_None);
338 return Py_None;
339 }
340 return PyString_FromString(descr->d_member->doc);
341 }
342
343 static PyGetSetDef member_getset[] = {
344 {"__doc__", (getter)member_get_doc},
345 {0}
346 };
347
348 static PyObject *
getset_get_doc(PyGetSetDescrObject * descr,void * closure)349 getset_get_doc(PyGetSetDescrObject *descr, void *closure)
350 {
351 if (descr->d_getset->doc == NULL) {
352 Py_INCREF(Py_None);
353 return Py_None;
354 }
355 return PyString_FromString(descr->d_getset->doc);
356 }
357
358 static PyGetSetDef getset_getset[] = {
359 {"__doc__", (getter)getset_get_doc},
360 {0}
361 };
362
363 static PyObject *
wrapperdescr_get_doc(PyWrapperDescrObject * descr,void * closure)364 wrapperdescr_get_doc(PyWrapperDescrObject *descr, void *closure)
365 {
366 if (descr->d_base->doc == NULL) {
367 Py_INCREF(Py_None);
368 return Py_None;
369 }
370 return PyString_FromString(descr->d_base->doc);
371 }
372
373 static PyGetSetDef wrapperdescr_getset[] = {
374 {"__doc__", (getter)wrapperdescr_get_doc},
375 {0}
376 };
377
378 static int
descr_traverse(PyObject * self,visitproc visit,void * arg)379 descr_traverse(PyObject *self, visitproc visit, void *arg)
380 {
381 PyDescrObject *descr = (PyDescrObject *)self;
382 Py_VISIT(descr->d_type);
383 return 0;
384 }
385
386 static PyTypeObject PyMethodDescr_Type = {
387 PyVarObject_HEAD_INIT(&PyType_Type, 0)
388 "method_descriptor",
389 sizeof(PyMethodDescrObject),
390 0,
391 (destructor)descr_dealloc, /* tp_dealloc */
392 0, /* tp_print */
393 0, /* tp_getattr */
394 0, /* tp_setattr */
395 0, /* tp_compare */
396 (reprfunc)method_repr, /* tp_repr */
397 0, /* tp_as_number */
398 0, /* tp_as_sequence */
399 0, /* tp_as_mapping */
400 0, /* tp_hash */
401 (ternaryfunc)methoddescr_call, /* tp_call */
402 0, /* tp_str */
403 PyObject_GenericGetAttr, /* tp_getattro */
404 0, /* tp_setattro */
405 0, /* tp_as_buffer */
406 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
407 0, /* tp_doc */
408 descr_traverse, /* tp_traverse */
409 0, /* tp_clear */
410 0, /* tp_richcompare */
411 0, /* tp_weaklistoffset */
412 0, /* tp_iter */
413 0, /* tp_iternext */
414 0, /* tp_methods */
415 descr_members, /* tp_members */
416 method_getset, /* tp_getset */
417 0, /* tp_base */
418 0, /* tp_dict */
419 (descrgetfunc)method_get, /* tp_descr_get */
420 0, /* tp_descr_set */
421 };
422
423 /* This is for METH_CLASS in C, not for "f = classmethod(f)" in Python! */
424 static PyTypeObject PyClassMethodDescr_Type = {
425 PyVarObject_HEAD_INIT(&PyType_Type, 0)
426 "classmethod_descriptor",
427 sizeof(PyMethodDescrObject),
428 0,
429 (destructor)descr_dealloc, /* tp_dealloc */
430 0, /* tp_print */
431 0, /* tp_getattr */
432 0, /* tp_setattr */
433 0, /* tp_compare */
434 (reprfunc)method_repr, /* tp_repr */
435 0, /* tp_as_number */
436 0, /* tp_as_sequence */
437 0, /* tp_as_mapping */
438 0, /* tp_hash */
439 (ternaryfunc)classmethoddescr_call, /* tp_call */
440 0, /* tp_str */
441 PyObject_GenericGetAttr, /* tp_getattro */
442 0, /* tp_setattro */
443 0, /* tp_as_buffer */
444 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
445 0, /* tp_doc */
446 descr_traverse, /* tp_traverse */
447 0, /* tp_clear */
448 0, /* tp_richcompare */
449 0, /* tp_weaklistoffset */
450 0, /* tp_iter */
451 0, /* tp_iternext */
452 0, /* tp_methods */
453 descr_members, /* tp_members */
454 method_getset, /* tp_getset */
455 0, /* tp_base */
456 0, /* tp_dict */
457 (descrgetfunc)classmethod_get, /* tp_descr_get */
458 0, /* tp_descr_set */
459 };
460
461 PyTypeObject PyMemberDescr_Type = {
462 PyVarObject_HEAD_INIT(&PyType_Type, 0)
463 "member_descriptor",
464 sizeof(PyMemberDescrObject),
465 0,
466 (destructor)descr_dealloc, /* tp_dealloc */
467 0, /* tp_print */
468 0, /* tp_getattr */
469 0, /* tp_setattr */
470 0, /* tp_compare */
471 (reprfunc)member_repr, /* tp_repr */
472 0, /* tp_as_number */
473 0, /* tp_as_sequence */
474 0, /* tp_as_mapping */
475 0, /* tp_hash */
476 0, /* tp_call */
477 0, /* tp_str */
478 PyObject_GenericGetAttr, /* tp_getattro */
479 0, /* tp_setattro */
480 0, /* tp_as_buffer */
481 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
482 0, /* tp_doc */
483 descr_traverse, /* tp_traverse */
484 0, /* tp_clear */
485 0, /* tp_richcompare */
486 0, /* tp_weaklistoffset */
487 0, /* tp_iter */
488 0, /* tp_iternext */
489 0, /* tp_methods */
490 descr_members, /* tp_members */
491 member_getset, /* tp_getset */
492 0, /* tp_base */
493 0, /* tp_dict */
494 (descrgetfunc)member_get, /* tp_descr_get */
495 (descrsetfunc)member_set, /* tp_descr_set */
496 };
497
498 PyTypeObject PyGetSetDescr_Type = {
499 PyVarObject_HEAD_INIT(&PyType_Type, 0)
500 "getset_descriptor",
501 sizeof(PyGetSetDescrObject),
502 0,
503 (destructor)descr_dealloc, /* tp_dealloc */
504 0, /* tp_print */
505 0, /* tp_getattr */
506 0, /* tp_setattr */
507 0, /* tp_compare */
508 (reprfunc)getset_repr, /* tp_repr */
509 0, /* tp_as_number */
510 0, /* tp_as_sequence */
511 0, /* tp_as_mapping */
512 0, /* tp_hash */
513 0, /* tp_call */
514 0, /* tp_str */
515 PyObject_GenericGetAttr, /* tp_getattro */
516 0, /* tp_setattro */
517 0, /* tp_as_buffer */
518 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
519 0, /* tp_doc */
520 descr_traverse, /* tp_traverse */
521 0, /* tp_clear */
522 0, /* tp_richcompare */
523 0, /* tp_weaklistoffset */
524 0, /* tp_iter */
525 0, /* tp_iternext */
526 0, /* tp_methods */
527 descr_members, /* tp_members */
528 getset_getset, /* tp_getset */
529 0, /* tp_base */
530 0, /* tp_dict */
531 (descrgetfunc)getset_get, /* tp_descr_get */
532 (descrsetfunc)getset_set, /* tp_descr_set */
533 };
534
535 PyTypeObject PyWrapperDescr_Type = {
536 PyVarObject_HEAD_INIT(&PyType_Type, 0)
537 "wrapper_descriptor",
538 sizeof(PyWrapperDescrObject),
539 0,
540 (destructor)descr_dealloc, /* tp_dealloc */
541 0, /* tp_print */
542 0, /* tp_getattr */
543 0, /* tp_setattr */
544 0, /* tp_compare */
545 (reprfunc)wrapperdescr_repr, /* tp_repr */
546 0, /* tp_as_number */
547 0, /* tp_as_sequence */
548 0, /* tp_as_mapping */
549 0, /* tp_hash */
550 (ternaryfunc)wrapperdescr_call, /* tp_call */
551 0, /* tp_str */
552 PyObject_GenericGetAttr, /* tp_getattro */
553 0, /* tp_setattro */
554 0, /* tp_as_buffer */
555 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
556 0, /* tp_doc */
557 descr_traverse, /* tp_traverse */
558 0, /* tp_clear */
559 0, /* tp_richcompare */
560 0, /* tp_weaklistoffset */
561 0, /* tp_iter */
562 0, /* tp_iternext */
563 0, /* tp_methods */
564 descr_members, /* tp_members */
565 wrapperdescr_getset, /* tp_getset */
566 0, /* tp_base */
567 0, /* tp_dict */
568 (descrgetfunc)wrapperdescr_get, /* tp_descr_get */
569 0, /* tp_descr_set */
570 };
571
572 static PyDescrObject *
descr_new(PyTypeObject * descrtype,PyTypeObject * type,const char * name)573 descr_new(PyTypeObject *descrtype, PyTypeObject *type, const char *name)
574 {
575 PyDescrObject *descr;
576
577 descr = (PyDescrObject *)PyType_GenericAlloc(descrtype, 0);
578 if (descr != NULL) {
579 Py_XINCREF(type);
580 descr->d_type = type;
581 descr->d_name = PyString_InternFromString(name);
582 if (descr->d_name == NULL) {
583 Py_DECREF(descr);
584 descr = NULL;
585 }
586 }
587 return descr;
588 }
589
590 PyObject *
PyDescr_NewMethod(PyTypeObject * type,PyMethodDef * method)591 PyDescr_NewMethod(PyTypeObject *type, PyMethodDef *method)
592 {
593 PyMethodDescrObject *descr;
594
595 descr = (PyMethodDescrObject *)descr_new(&PyMethodDescr_Type,
596 type, method->ml_name);
597 if (descr != NULL)
598 descr->d_method = method;
599 return (PyObject *)descr;
600 }
601
602 PyObject *
PyDescr_NewClassMethod(PyTypeObject * type,PyMethodDef * method)603 PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)
604 {
605 PyMethodDescrObject *descr;
606
607 descr = (PyMethodDescrObject *)descr_new(&PyClassMethodDescr_Type,
608 type, method->ml_name);
609 if (descr != NULL)
610 descr->d_method = method;
611 return (PyObject *)descr;
612 }
613
614 PyObject *
PyDescr_NewMember(PyTypeObject * type,PyMemberDef * member)615 PyDescr_NewMember(PyTypeObject *type, PyMemberDef *member)
616 {
617 PyMemberDescrObject *descr;
618
619 descr = (PyMemberDescrObject *)descr_new(&PyMemberDescr_Type,
620 type, member->name);
621 if (descr != NULL)
622 descr->d_member = member;
623 return (PyObject *)descr;
624 }
625
626 PyObject *
PyDescr_NewGetSet(PyTypeObject * type,PyGetSetDef * getset)627 PyDescr_NewGetSet(PyTypeObject *type, PyGetSetDef *getset)
628 {
629 PyGetSetDescrObject *descr;
630
631 descr = (PyGetSetDescrObject *)descr_new(&PyGetSetDescr_Type,
632 type, getset->name);
633 if (descr != NULL)
634 descr->d_getset = getset;
635 return (PyObject *)descr;
636 }
637
638 PyObject *
PyDescr_NewWrapper(PyTypeObject * type,struct wrapperbase * base,void * wrapped)639 PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
640 {
641 PyWrapperDescrObject *descr;
642
643 descr = (PyWrapperDescrObject *)descr_new(&PyWrapperDescr_Type,
644 type, base->name);
645 if (descr != NULL) {
646 descr->d_base = base;
647 descr->d_wrapped = wrapped;
648 }
649 return (PyObject *)descr;
650 }
651
652
653 /* --- Readonly proxy for dictionaries (actually any mapping) --- */
654
655 /* This has no reason to be in this file except that adding new files is a
656 bit of a pain */
657
658 typedef struct {
659 PyObject_HEAD
660 PyObject *dict;
661 } proxyobject;
662
663 static Py_ssize_t
proxy_len(proxyobject * pp)664 proxy_len(proxyobject *pp)
665 {
666 return PyObject_Size(pp->dict);
667 }
668
669 static PyObject *
proxy_getitem(proxyobject * pp,PyObject * key)670 proxy_getitem(proxyobject *pp, PyObject *key)
671 {
672 return PyObject_GetItem(pp->dict, key);
673 }
674
675 static PyMappingMethods proxy_as_mapping = {
676 (lenfunc)proxy_len, /* mp_length */
677 (binaryfunc)proxy_getitem, /* mp_subscript */
678 0, /* mp_ass_subscript */
679 };
680
681 static int
proxy_contains(proxyobject * pp,PyObject * key)682 proxy_contains(proxyobject *pp, PyObject *key)
683 {
684 return PyDict_Contains(pp->dict, key);
685 }
686
687 static PySequenceMethods proxy_as_sequence = {
688 0, /* sq_length */
689 0, /* sq_concat */
690 0, /* sq_repeat */
691 0, /* sq_item */
692 0, /* sq_slice */
693 0, /* sq_ass_item */
694 0, /* sq_ass_slice */
695 (objobjproc)proxy_contains, /* sq_contains */
696 0, /* sq_inplace_concat */
697 0, /* sq_inplace_repeat */
698 };
699
700 static PyObject *
proxy_has_key(proxyobject * pp,PyObject * key)701 proxy_has_key(proxyobject *pp, PyObject *key)
702 {
703 int res = PyDict_Contains(pp->dict, key);
704 if (res < 0)
705 return NULL;
706 return PyBool_FromLong(res);
707 }
708
709 static PyObject *
proxy_get(proxyobject * pp,PyObject * args)710 proxy_get(proxyobject *pp, PyObject *args)
711 {
712 PyObject *key, *def = Py_None;
713
714 if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &def))
715 return NULL;
716 return PyObject_CallMethod(pp->dict, "get", "(OO)", key, def);
717 }
718
719 static PyObject *
proxy_keys(proxyobject * pp)720 proxy_keys(proxyobject *pp)
721 {
722 return PyMapping_Keys(pp->dict);
723 }
724
725 static PyObject *
proxy_values(proxyobject * pp)726 proxy_values(proxyobject *pp)
727 {
728 return PyMapping_Values(pp->dict);
729 }
730
731 static PyObject *
proxy_items(proxyobject * pp)732 proxy_items(proxyobject *pp)
733 {
734 return PyMapping_Items(pp->dict);
735 }
736
737 static PyObject *
proxy_iterkeys(proxyobject * pp)738 proxy_iterkeys(proxyobject *pp)
739 {
740 return PyObject_CallMethod(pp->dict, "iterkeys", NULL);
741 }
742
743 static PyObject *
proxy_itervalues(proxyobject * pp)744 proxy_itervalues(proxyobject *pp)
745 {
746 return PyObject_CallMethod(pp->dict, "itervalues", NULL);
747 }
748
749 static PyObject *
proxy_iteritems(proxyobject * pp)750 proxy_iteritems(proxyobject *pp)
751 {
752 return PyObject_CallMethod(pp->dict, "iteritems", NULL);
753 }
754 static PyObject *
proxy_copy(proxyobject * pp)755 proxy_copy(proxyobject *pp)
756 {
757 return PyObject_CallMethod(pp->dict, "copy", NULL);
758 }
759
760 static PyMethodDef proxy_methods[] = {
761 {"has_key", (PyCFunction)proxy_has_key, METH_O,
762 PyDoc_STR("D.has_key(k) -> True if D has a key k, else False")},
763 {"get", (PyCFunction)proxy_get, METH_VARARGS,
764 PyDoc_STR("D.get(k[,d]) -> D[k] if D.has_key(k), else d."
765 " d defaults to None.")},
766 {"keys", (PyCFunction)proxy_keys, METH_NOARGS,
767 PyDoc_STR("D.keys() -> list of D's keys")},
768 {"values", (PyCFunction)proxy_values, METH_NOARGS,
769 PyDoc_STR("D.values() -> list of D's values")},
770 {"items", (PyCFunction)proxy_items, METH_NOARGS,
771 PyDoc_STR("D.items() -> list of D's (key, value) pairs, as 2-tuples")},
772 {"iterkeys", (PyCFunction)proxy_iterkeys, METH_NOARGS,
773 PyDoc_STR("D.iterkeys() -> an iterator over the keys of D")},
774 {"itervalues",(PyCFunction)proxy_itervalues, METH_NOARGS,
775 PyDoc_STR("D.itervalues() -> an iterator over the values of D")},
776 {"iteritems", (PyCFunction)proxy_iteritems, METH_NOARGS,
777 PyDoc_STR("D.iteritems() ->"
778 " an iterator over the (key, value) items of D")},
779 {"copy", (PyCFunction)proxy_copy, METH_NOARGS,
780 PyDoc_STR("D.copy() -> a shallow copy of D")},
781 {0}
782 };
783
784 static void
proxy_dealloc(proxyobject * pp)785 proxy_dealloc(proxyobject *pp)
786 {
787 _PyObject_GC_UNTRACK(pp);
788 Py_DECREF(pp->dict);
789 PyObject_GC_Del(pp);
790 }
791
792 static PyObject *
proxy_getiter(proxyobject * pp)793 proxy_getiter(proxyobject *pp)
794 {
795 return PyObject_GetIter(pp->dict);
796 }
797
798 static PyObject *
proxy_str(proxyobject * pp)799 proxy_str(proxyobject *pp)
800 {
801 return PyObject_Str(pp->dict);
802 }
803
804 static int
proxy_traverse(PyObject * self,visitproc visit,void * arg)805 proxy_traverse(PyObject *self, visitproc visit, void *arg)
806 {
807 proxyobject *pp = (proxyobject *)self;
808 Py_VISIT(pp->dict);
809 return 0;
810 }
811
812 static int
proxy_compare(proxyobject * v,PyObject * w)813 proxy_compare(proxyobject *v, PyObject *w)
814 {
815 return PyObject_Compare(v->dict, w);
816 }
817
818 static PyObject *
proxy_richcompare(proxyobject * v,PyObject * w,int op)819 proxy_richcompare(proxyobject *v, PyObject *w, int op)
820 {
821 return PyObject_RichCompare(v->dict, w, op);
822 }
823
824 PyTypeObject PyDictProxy_Type = {
825 PyVarObject_HEAD_INIT(&PyType_Type, 0)
826 "dictproxy", /* tp_name */
827 sizeof(proxyobject), /* tp_basicsize */
828 0, /* tp_itemsize */
829 /* methods */
830 (destructor)proxy_dealloc, /* tp_dealloc */
831 0, /* tp_print */
832 0, /* tp_getattr */
833 0, /* tp_setattr */
834 (cmpfunc)proxy_compare, /* tp_compare */
835 0, /* tp_repr */
836 0, /* tp_as_number */
837 &proxy_as_sequence, /* tp_as_sequence */
838 &proxy_as_mapping, /* tp_as_mapping */
839 0, /* tp_hash */
840 0, /* tp_call */
841 (reprfunc)proxy_str, /* tp_str */
842 PyObject_GenericGetAttr, /* tp_getattro */
843 0, /* tp_setattro */
844 0, /* tp_as_buffer */
845 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
846 0, /* tp_doc */
847 proxy_traverse, /* tp_traverse */
848 0, /* tp_clear */
849 (richcmpfunc)proxy_richcompare, /* tp_richcompare */
850 0, /* tp_weaklistoffset */
851 (getiterfunc)proxy_getiter, /* tp_iter */
852 0, /* tp_iternext */
853 proxy_methods, /* tp_methods */
854 0, /* tp_members */
855 0, /* tp_getset */
856 0, /* tp_base */
857 0, /* tp_dict */
858 0, /* tp_descr_get */
859 0, /* tp_descr_set */
860 };
861
862 PyObject *
PyDictProxy_New(PyObject * dict)863 PyDictProxy_New(PyObject *dict)
864 {
865 proxyobject *pp;
866
867 pp = PyObject_GC_New(proxyobject, &PyDictProxy_Type);
868 if (pp != NULL) {
869 Py_INCREF(dict);
870 pp->dict = dict;
871 _PyObject_GC_TRACK(pp);
872 }
873 return (PyObject *)pp;
874 }
875
876
877 /* --- Wrapper object for "slot" methods --- */
878
879 /* This has no reason to be in this file except that adding new files is a
880 bit of a pain */
881
882 typedef struct {
883 PyObject_HEAD
884 PyWrapperDescrObject *descr;
885 PyObject *self;
886 } wrapperobject;
887
888 static void
wrapper_dealloc(wrapperobject * wp)889 wrapper_dealloc(wrapperobject *wp)
890 {
891 PyObject_GC_UnTrack(wp);
892 Py_TRASHCAN_SAFE_BEGIN(wp)
893 Py_XDECREF(wp->descr);
894 Py_XDECREF(wp->self);
895 PyObject_GC_Del(wp);
896 Py_TRASHCAN_SAFE_END(wp)
897 }
898
899 static int
wrapper_compare(wrapperobject * a,wrapperobject * b)900 wrapper_compare(wrapperobject *a, wrapperobject *b)
901 {
902 if (a->descr == b->descr)
903 return PyObject_Compare(a->self, b->self);
904 else
905 return (a->descr < b->descr) ? -1 : 1;
906 }
907
908 static long
wrapper_hash(wrapperobject * wp)909 wrapper_hash(wrapperobject *wp)
910 {
911 int x, y;
912 x = _Py_HashPointer(wp->descr);
913 if (x == -1)
914 return -1;
915 y = PyObject_Hash(wp->self);
916 if (y == -1)
917 return -1;
918 x = x ^ y;
919 if (x == -1)
920 x = -2;
921 return x;
922 }
923
924 static PyObject *
wrapper_repr(wrapperobject * wp)925 wrapper_repr(wrapperobject *wp)
926 {
927 return PyString_FromFormat("<method-wrapper '%s' of %s object at %p>",
928 wp->descr->d_base->name,
929 wp->self->ob_type->tp_name,
930 wp->self);
931 }
932
933 static PyMemberDef wrapper_members[] = {
934 {"__self__", T_OBJECT, offsetof(wrapperobject, self), READONLY},
935 {0}
936 };
937
938 static PyObject *
wrapper_objclass(wrapperobject * wp)939 wrapper_objclass(wrapperobject *wp)
940 {
941 PyObject *c = (PyObject *)wp->descr->d_type;
942
943 Py_INCREF(c);
944 return c;
945 }
946
947 static PyObject *
wrapper_name(wrapperobject * wp)948 wrapper_name(wrapperobject *wp)
949 {
950 char *s = wp->descr->d_base->name;
951
952 return PyString_FromString(s);
953 }
954
955 static PyObject *
wrapper_doc(wrapperobject * wp)956 wrapper_doc(wrapperobject *wp)
957 {
958 char *s = wp->descr->d_base->doc;
959
960 if (s == NULL) {
961 Py_INCREF(Py_None);
962 return Py_None;
963 }
964 else {
965 return PyString_FromString(s);
966 }
967 }
968
969 static PyGetSetDef wrapper_getsets[] = {
970 {"__objclass__", (getter)wrapper_objclass},
971 {"__name__", (getter)wrapper_name},
972 {"__doc__", (getter)wrapper_doc},
973 {0}
974 };
975
976 static PyObject *
wrapper_call(wrapperobject * wp,PyObject * args,PyObject * kwds)977 wrapper_call(wrapperobject *wp, PyObject *args, PyObject *kwds)
978 {
979 wrapperfunc wrapper = wp->descr->d_base->wrapper;
980 PyObject *self = wp->self;
981
982 if (wp->descr->d_base->flags & PyWrapperFlag_KEYWORDS) {
983 wrapperfunc_kwds wk = (wrapperfunc_kwds)wrapper;
984 return (*wk)(self, args, wp->descr->d_wrapped, kwds);
985 }
986
987 if (kwds != NULL && (!PyDict_Check(kwds) || PyDict_Size(kwds) != 0)) {
988 PyErr_Format(PyExc_TypeError,
989 "wrapper %s doesn't take keyword arguments",
990 wp->descr->d_base->name);
991 return NULL;
992 }
993 return (*wrapper)(self, args, wp->descr->d_wrapped);
994 }
995
996 static int
wrapper_traverse(PyObject * self,visitproc visit,void * arg)997 wrapper_traverse(PyObject *self, visitproc visit, void *arg)
998 {
999 wrapperobject *wp = (wrapperobject *)self;
1000 Py_VISIT(wp->descr);
1001 Py_VISIT(wp->self);
1002 return 0;
1003 }
1004
1005 static PyTypeObject wrappertype = {
1006 PyVarObject_HEAD_INIT(&PyType_Type, 0)
1007 "method-wrapper", /* tp_name */
1008 sizeof(wrapperobject), /* tp_basicsize */
1009 0, /* tp_itemsize */
1010 /* methods */
1011 (destructor)wrapper_dealloc, /* tp_dealloc */
1012 0, /* tp_print */
1013 0, /* tp_getattr */
1014 0, /* tp_setattr */
1015 (cmpfunc)wrapper_compare, /* tp_compare */
1016 (reprfunc)wrapper_repr, /* tp_repr */
1017 0, /* tp_as_number */
1018 0, /* tp_as_sequence */
1019 0, /* tp_as_mapping */
1020 (hashfunc)wrapper_hash, /* tp_hash */
1021 (ternaryfunc)wrapper_call, /* tp_call */
1022 0, /* tp_str */
1023 PyObject_GenericGetAttr, /* tp_getattro */
1024 0, /* tp_setattro */
1025 0, /* tp_as_buffer */
1026 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
1027 0, /* tp_doc */
1028 wrapper_traverse, /* tp_traverse */
1029 0, /* tp_clear */
1030 0, /* tp_richcompare */
1031 0, /* tp_weaklistoffset */
1032 0, /* tp_iter */
1033 0, /* tp_iternext */
1034 0, /* tp_methods */
1035 wrapper_members, /* tp_members */
1036 wrapper_getsets, /* tp_getset */
1037 0, /* tp_base */
1038 0, /* tp_dict */
1039 0, /* tp_descr_get */
1040 0, /* tp_descr_set */
1041 };
1042
1043 PyObject *
PyWrapper_New(PyObject * d,PyObject * self)1044 PyWrapper_New(PyObject *d, PyObject *self)
1045 {
1046 wrapperobject *wp;
1047 PyWrapperDescrObject *descr;
1048
1049 assert(PyObject_TypeCheck(d, &PyWrapperDescr_Type));
1050 descr = (PyWrapperDescrObject *)d;
1051 assert(_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
1052 (PyObject *)(descr->d_type)));
1053
1054 wp = PyObject_GC_New(wrapperobject, &wrappertype);
1055 if (wp != NULL) {
1056 Py_INCREF(descr);
1057 wp->descr = descr;
1058 Py_INCREF(self);
1059 wp->self = self;
1060 _PyObject_GC_TRACK(wp);
1061 }
1062 return (PyObject *)wp;
1063 }
1064
1065
1066 /* A built-in 'property' type */
1067
1068 /*
1069 class property(object):
1070
1071 def __init__(self, fget=None, fset=None, fdel=None, doc=None):
1072 if doc is None and fget is not None and hasattr(fget, "__doc__"):
1073 doc = fget.__doc__
1074 self.__get = fget
1075 self.__set = fset
1076 self.__del = fdel
1077 self.__doc__ = doc
1078
1079 def __get__(self, inst, type=None):
1080 if inst is None:
1081 return self
1082 if self.__get is None:
1083 raise AttributeError, "unreadable attribute"
1084 return self.__get(inst)
1085
1086 def __set__(self, inst, value):
1087 if self.__set is None:
1088 raise AttributeError, "can't set attribute"
1089 return self.__set(inst, value)
1090
1091 def __delete__(self, inst):
1092 if self.__del is None:
1093 raise AttributeError, "can't delete attribute"
1094 return self.__del(inst)
1095
1096 */
1097
1098 typedef struct {
1099 PyObject_HEAD
1100 PyObject *prop_get;
1101 PyObject *prop_set;
1102 PyObject *prop_del;
1103 PyObject *prop_doc;
1104 int getter_doc;
1105 } propertyobject;
1106
1107 static PyObject * property_copy(PyObject *, PyObject *, PyObject *,
1108 PyObject *);
1109
1110 static PyMemberDef property_members[] = {
1111 {"fget", T_OBJECT, offsetof(propertyobject, prop_get), READONLY},
1112 {"fset", T_OBJECT, offsetof(propertyobject, prop_set), READONLY},
1113 {"fdel", T_OBJECT, offsetof(propertyobject, prop_del), READONLY},
1114 {"__doc__", T_OBJECT, offsetof(propertyobject, prop_doc), READONLY},
1115 {0}
1116 };
1117
1118
1119 PyDoc_STRVAR(getter_doc,
1120 "Descriptor to change the getter on a property.");
1121
1122 static PyObject *
property_getter(PyObject * self,PyObject * getter)1123 property_getter(PyObject *self, PyObject *getter)
1124 {
1125 return property_copy(self, getter, NULL, NULL);
1126 }
1127
1128
1129 PyDoc_STRVAR(setter_doc,
1130 "Descriptor to change the setter on a property.");
1131
1132 static PyObject *
property_setter(PyObject * self,PyObject * setter)1133 property_setter(PyObject *self, PyObject *setter)
1134 {
1135 return property_copy(self, NULL, setter, NULL);
1136 }
1137
1138
1139 PyDoc_STRVAR(deleter_doc,
1140 "Descriptor to change the deleter on a property.");
1141
1142 static PyObject *
property_deleter(PyObject * self,PyObject * deleter)1143 property_deleter(PyObject *self, PyObject *deleter)
1144 {
1145 return property_copy(self, NULL, NULL, deleter);
1146 }
1147
1148
1149 static PyMethodDef property_methods[] = {
1150 {"getter", property_getter, METH_O, getter_doc},
1151 {"setter", property_setter, METH_O, setter_doc},
1152 {"deleter", property_deleter, METH_O, deleter_doc},
1153 {0}
1154 };
1155
1156
1157 static void
property_dealloc(PyObject * self)1158 property_dealloc(PyObject *self)
1159 {
1160 propertyobject *gs = (propertyobject *)self;
1161
1162 _PyObject_GC_UNTRACK(self);
1163 Py_XDECREF(gs->prop_get);
1164 Py_XDECREF(gs->prop_set);
1165 Py_XDECREF(gs->prop_del);
1166 Py_XDECREF(gs->prop_doc);
1167 self->ob_type->tp_free(self);
1168 }
1169
1170 static PyObject *
property_descr_get(PyObject * self,PyObject * obj,PyObject * type)1171 property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
1172 {
1173 propertyobject *gs = (propertyobject *)self;
1174
1175 if (obj == NULL || obj == Py_None) {
1176 Py_INCREF(self);
1177 return self;
1178 }
1179 if (gs->prop_get == NULL) {
1180 PyErr_SetString(PyExc_AttributeError, "unreadable attribute");
1181 return NULL;
1182 }
1183 return PyObject_CallFunction(gs->prop_get, "(O)", obj);
1184 }
1185
1186 static int
property_descr_set(PyObject * self,PyObject * obj,PyObject * value)1187 property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
1188 {
1189 propertyobject *gs = (propertyobject *)self;
1190 PyObject *func, *res;
1191
1192 if (value == NULL)
1193 func = gs->prop_del;
1194 else
1195 func = gs->prop_set;
1196 if (func == NULL) {
1197 PyErr_SetString(PyExc_AttributeError,
1198 value == NULL ?
1199 "can't delete attribute" :
1200 "can't set attribute");
1201 return -1;
1202 }
1203 if (value == NULL)
1204 res = PyObject_CallFunction(func, "(O)", obj);
1205 else
1206 res = PyObject_CallFunction(func, "(OO)", obj, value);
1207 if (res == NULL)
1208 return -1;
1209 Py_DECREF(res);
1210 return 0;
1211 }
1212
1213 static PyObject *
property_copy(PyObject * old,PyObject * get,PyObject * set,PyObject * del)1214 property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del)
1215 {
1216 propertyobject *pold = (propertyobject *)old;
1217 PyObject *new, *type, *doc;
1218
1219 type = PyObject_Type(old);
1220 if (type == NULL)
1221 return NULL;
1222
1223 if (get == NULL || get == Py_None) {
1224 Py_XDECREF(get);
1225 get = pold->prop_get ? pold->prop_get : Py_None;
1226 }
1227 if (set == NULL || set == Py_None) {
1228 Py_XDECREF(set);
1229 set = pold->prop_set ? pold->prop_set : Py_None;
1230 }
1231 if (del == NULL || del == Py_None) {
1232 Py_XDECREF(del);
1233 del = pold->prop_del ? pold->prop_del : Py_None;
1234 }
1235 if (pold->getter_doc && get != Py_None) {
1236 /* make _init use __doc__ from getter */
1237 doc = Py_None;
1238 }
1239 else {
1240 doc = pold->prop_doc ? pold->prop_doc : Py_None;
1241 }
1242
1243 new = PyObject_CallFunction(type, "OOOO", get, set, del, doc);
1244 Py_DECREF(type);
1245 if (new == NULL)
1246 return NULL;
1247 return new;
1248 }
1249
1250 static int
property_init(PyObject * self,PyObject * args,PyObject * kwds)1251 property_init(PyObject *self, PyObject *args, PyObject *kwds)
1252 {
1253 PyObject *get = NULL, *set = NULL, *del = NULL, *doc = NULL;
1254 static char *kwlist[] = {"fget", "fset", "fdel", "doc", 0};
1255 propertyobject *prop = (propertyobject *)self;
1256
1257 if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOOO:property",
1258 kwlist, &get, &set, &del, &doc))
1259 return -1;
1260
1261 if (get == Py_None)
1262 get = NULL;
1263 if (set == Py_None)
1264 set = NULL;
1265 if (del == Py_None)
1266 del = NULL;
1267
1268 Py_XINCREF(get);
1269 Py_XINCREF(set);
1270 Py_XINCREF(del);
1271 Py_XINCREF(doc);
1272
1273 prop->prop_get = get;
1274 prop->prop_set = set;
1275 prop->prop_del = del;
1276 prop->prop_doc = doc;
1277 prop->getter_doc = 0;
1278
1279 /* if no docstring given and the getter has one, use that one */
1280 if ((doc == NULL || doc == Py_None) && get != NULL) {
1281 PyObject *get_doc = PyObject_GetAttrString(get, "__doc__");
1282 if (get_doc) {
1283 if (Py_TYPE(self) == &PyProperty_Type) {
1284 Py_XDECREF(prop->prop_doc);
1285 prop->prop_doc = get_doc;
1286 }
1287 else {
1288 /* If this is a property subclass, put __doc__
1289 in dict of the subclass instance instead,
1290 otherwise it gets shadowed by __doc__ in the
1291 class's dict. */
1292 int err = PyObject_SetAttrString(self, "__doc__", get_doc);
1293 Py_DECREF(get_doc);
1294 if (err < 0)
1295 return -1;
1296 }
1297 prop->getter_doc = 1;
1298 }
1299 else if (PyErr_ExceptionMatches(PyExc_Exception)) {
1300 PyErr_Clear();
1301 }
1302 else {
1303 return -1;
1304 }
1305 }
1306
1307 return 0;
1308 }
1309
1310 PyDoc_STRVAR(property_doc,
1311 "property(fget=None, fset=None, fdel=None, doc=None) -> property attribute\n"
1312 "\n"
1313 "fget is a function to be used for getting an attribute value, and likewise\n"
1314 "fset is a function for setting, and fdel a function for del'ing, an\n"
1315 "attribute. Typical use is to define a managed attribute x:\n"
1316 "class C(object):\n"
1317 " def getx(self): return self._x\n"
1318 " def setx(self, value): self._x = value\n"
1319 " def delx(self): del self._x\n"
1320 " x = property(getx, setx, delx, \"I'm the 'x' property.\")\n"
1321 "\n"
1322 "Decorators make defining new properties or modifying existing ones easy:\n"
1323 "class C(object):\n"
1324 " @property\n"
1325 " def x(self): return self._x\n"
1326 " @x.setter\n"
1327 " def x(self, value): self._x = value\n"
1328 " @x.deleter\n"
1329 " def x(self): del self._x\n"
1330 );
1331
1332 static int
property_traverse(PyObject * self,visitproc visit,void * arg)1333 property_traverse(PyObject *self, visitproc visit, void *arg)
1334 {
1335 propertyobject *pp = (propertyobject *)self;
1336 Py_VISIT(pp->prop_get);
1337 Py_VISIT(pp->prop_set);
1338 Py_VISIT(pp->prop_del);
1339 Py_VISIT(pp->prop_doc);
1340 return 0;
1341 }
1342
1343 PyTypeObject PyProperty_Type = {
1344 PyVarObject_HEAD_INIT(&PyType_Type, 0)
1345 "property", /* tp_name */
1346 sizeof(propertyobject), /* tp_basicsize */
1347 0, /* tp_itemsize */
1348 /* methods */
1349 property_dealloc, /* tp_dealloc */
1350 0, /* tp_print */
1351 0, /* tp_getattr */
1352 0, /* tp_setattr */
1353 0, /* tp_compare */
1354 0, /* tp_repr */
1355 0, /* tp_as_number */
1356 0, /* tp_as_sequence */
1357 0, /* tp_as_mapping */
1358 0, /* tp_hash */
1359 0, /* tp_call */
1360 0, /* tp_str */
1361 PyObject_GenericGetAttr, /* tp_getattro */
1362 0, /* tp_setattro */
1363 0, /* tp_as_buffer */
1364 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
1365 Py_TPFLAGS_BASETYPE, /* tp_flags */
1366 property_doc, /* tp_doc */
1367 property_traverse, /* tp_traverse */
1368 0, /* tp_clear */
1369 0, /* tp_richcompare */
1370 0, /* tp_weaklistoffset */
1371 0, /* tp_iter */
1372 0, /* tp_iternext */
1373 property_methods, /* tp_methods */
1374 property_members, /* tp_members */
1375 0, /* tp_getset */
1376 0, /* tp_base */
1377 0, /* tp_dict */
1378 property_descr_get, /* tp_descr_get */
1379 property_descr_set, /* tp_descr_set */
1380 0, /* tp_dictoffset */
1381 property_init, /* tp_init */
1382 PyType_GenericAlloc, /* tp_alloc */
1383 PyType_GenericNew, /* tp_new */
1384 PyObject_GC_Del, /* tp_free */
1385 };
1386