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 Py_ssize_t argc;
258 PyObject *self, *func, *result;
259
260 /* Make sure that the first argument is acceptable as 'self' */
261 assert(PyTuple_Check(args));
262 argc = PyTuple_GET_SIZE(args);
263 if (argc < 1) {
264 PyErr_Format(PyExc_TypeError,
265 "descriptor '%s' of '%.100s' "
266 "object needs an argument",
267 descr_name((PyDescrObject *)descr),
268 descr->d_type->tp_name);
269 return NULL;
270 }
271 self = PyTuple_GET_ITEM(args, 0);
272 if (!PyType_Check(self)) {
273 PyErr_Format(PyExc_TypeError,
274 "descriptor '%s' requires a type "
275 "but received a '%.100s'",
276 descr_name((PyDescrObject *)descr),
277 self->ob_type->tp_name);
278 return NULL;
279 }
280 if (!PyType_IsSubtype((PyTypeObject *)self, descr->d_type)) {
281 PyErr_Format(PyExc_TypeError,
282 "descriptor '%s' "
283 "requires a subtype of '%.100s' "
284 "but received '%.100s",
285 descr_name((PyDescrObject *)descr),
286 descr->d_type->tp_name,
287 self->ob_type->tp_name);
288 return NULL;
289 }
290
291 func = PyCFunction_New(descr->d_method, self);
292 if (func == NULL)
293 return NULL;
294 args = PyTuple_GetSlice(args, 1, argc);
295 if (args == NULL) {
296 Py_DECREF(func);
297 return NULL;
298 }
299 result = PyEval_CallObjectWithKeywords(func, args, kwds);
300 Py_DECREF(func);
301 Py_DECREF(args);
302 return result;
303 }
304
305 static PyObject *
wrapperdescr_call(PyWrapperDescrObject * descr,PyObject * args,PyObject * kwds)306 wrapperdescr_call(PyWrapperDescrObject *descr, PyObject *args, PyObject *kwds)
307 {
308 Py_ssize_t argc;
309 PyObject *self, *func, *result;
310
311 /* Make sure that the first argument is acceptable as 'self' */
312 assert(PyTuple_Check(args));
313 argc = PyTuple_GET_SIZE(args);
314 if (argc < 1) {
315 PyErr_Format(PyExc_TypeError,
316 "descriptor '%.300s' of '%.100s' "
317 "object needs an argument",
318 descr_name((PyDescrObject *)descr),
319 descr->d_type->tp_name);
320 return NULL;
321 }
322 self = PyTuple_GET_ITEM(args, 0);
323 if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
324 (PyObject *)(descr->d_type))) {
325 PyErr_Format(PyExc_TypeError,
326 "descriptor '%.200s' "
327 "requires a '%.100s' object "
328 "but received a '%.100s'",
329 descr_name((PyDescrObject *)descr),
330 descr->d_type->tp_name,
331 self->ob_type->tp_name);
332 return NULL;
333 }
334
335 func = PyWrapper_New((PyObject *)descr, self);
336 if (func == NULL)
337 return NULL;
338 args = PyTuple_GetSlice(args, 1, argc);
339 if (args == NULL) {
340 Py_DECREF(func);
341 return NULL;
342 }
343 result = PyEval_CallObjectWithKeywords(func, args, kwds);
344 Py_DECREF(args);
345 Py_DECREF(func);
346 return result;
347 }
348
349 static PyObject *
method_get_doc(PyMethodDescrObject * descr,void * closure)350 method_get_doc(PyMethodDescrObject *descr, void *closure)
351 {
352 if (descr->d_method->ml_doc == NULL) {
353 Py_INCREF(Py_None);
354 return Py_None;
355 }
356 return PyString_FromString(descr->d_method->ml_doc);
357 }
358
359 static PyMemberDef descr_members[] = {
360 {"__objclass__", T_OBJECT, offsetof(PyDescrObject, d_type), READONLY},
361 {"__name__", T_OBJECT, offsetof(PyDescrObject, d_name), READONLY},
362 {0}
363 };
364
365 static PyGetSetDef method_getset[] = {
366 {"__doc__", (getter)method_get_doc},
367 {0}
368 };
369
370 static PyObject *
member_get_doc(PyMemberDescrObject * descr,void * closure)371 member_get_doc(PyMemberDescrObject *descr, void *closure)
372 {
373 if (descr->d_member->doc == NULL) {
374 Py_INCREF(Py_None);
375 return Py_None;
376 }
377 return PyString_FromString(descr->d_member->doc);
378 }
379
380 static PyGetSetDef member_getset[] = {
381 {"__doc__", (getter)member_get_doc},
382 {0}
383 };
384
385 static PyObject *
getset_get_doc(PyGetSetDescrObject * descr,void * closure)386 getset_get_doc(PyGetSetDescrObject *descr, void *closure)
387 {
388 if (descr->d_getset->doc == NULL) {
389 Py_INCREF(Py_None);
390 return Py_None;
391 }
392 return PyString_FromString(descr->d_getset->doc);
393 }
394
395 static PyGetSetDef getset_getset[] = {
396 {"__doc__", (getter)getset_get_doc},
397 {0}
398 };
399
400 static PyObject *
wrapperdescr_get_doc(PyWrapperDescrObject * descr,void * closure)401 wrapperdescr_get_doc(PyWrapperDescrObject *descr, void *closure)
402 {
403 if (descr->d_base->doc == NULL) {
404 Py_INCREF(Py_None);
405 return Py_None;
406 }
407 return PyString_FromString(descr->d_base->doc);
408 }
409
410 static PyGetSetDef wrapperdescr_getset[] = {
411 {"__doc__", (getter)wrapperdescr_get_doc},
412 {0}
413 };
414
415 static int
descr_traverse(PyObject * self,visitproc visit,void * arg)416 descr_traverse(PyObject *self, visitproc visit, void *arg)
417 {
418 PyDescrObject *descr = (PyDescrObject *)self;
419 Py_VISIT(descr->d_type);
420 return 0;
421 }
422
423 static PyTypeObject PyMethodDescr_Type = {
424 PyVarObject_HEAD_INIT(&PyType_Type, 0)
425 "method_descriptor",
426 sizeof(PyMethodDescrObject),
427 0,
428 (destructor)descr_dealloc, /* tp_dealloc */
429 0, /* tp_print */
430 0, /* tp_getattr */
431 0, /* tp_setattr */
432 0, /* tp_compare */
433 (reprfunc)method_repr, /* tp_repr */
434 0, /* tp_as_number */
435 0, /* tp_as_sequence */
436 0, /* tp_as_mapping */
437 0, /* tp_hash */
438 (ternaryfunc)methoddescr_call, /* tp_call */
439 0, /* tp_str */
440 PyObject_GenericGetAttr, /* tp_getattro */
441 0, /* tp_setattro */
442 0, /* tp_as_buffer */
443 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
444 0, /* tp_doc */
445 descr_traverse, /* tp_traverse */
446 0, /* tp_clear */
447 0, /* tp_richcompare */
448 0, /* tp_weaklistoffset */
449 0, /* tp_iter */
450 0, /* tp_iternext */
451 0, /* tp_methods */
452 descr_members, /* tp_members */
453 method_getset, /* tp_getset */
454 0, /* tp_base */
455 0, /* tp_dict */
456 (descrgetfunc)method_get, /* tp_descr_get */
457 0, /* tp_descr_set */
458 };
459
460 /* This is for METH_CLASS in C, not for "f = classmethod(f)" in Python! */
461 static PyTypeObject PyClassMethodDescr_Type = {
462 PyVarObject_HEAD_INIT(&PyType_Type, 0)
463 "classmethod_descriptor",
464 sizeof(PyMethodDescrObject),
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)method_repr, /* tp_repr */
472 0, /* tp_as_number */
473 0, /* tp_as_sequence */
474 0, /* tp_as_mapping */
475 0, /* tp_hash */
476 (ternaryfunc)classmethoddescr_call, /* 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 method_getset, /* tp_getset */
492 0, /* tp_base */
493 0, /* tp_dict */
494 (descrgetfunc)classmethod_get, /* tp_descr_get */
495 0, /* tp_descr_set */
496 };
497
498 PyTypeObject PyMemberDescr_Type = {
499 PyVarObject_HEAD_INIT(&PyType_Type, 0)
500 "member_descriptor",
501 sizeof(PyMemberDescrObject),
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)member_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 member_getset, /* tp_getset */
529 0, /* tp_base */
530 0, /* tp_dict */
531 (descrgetfunc)member_get, /* tp_descr_get */
532 (descrsetfunc)member_set, /* tp_descr_set */
533 };
534
535 PyTypeObject PyGetSetDescr_Type = {
536 PyVarObject_HEAD_INIT(&PyType_Type, 0)
537 "getset_descriptor",
538 sizeof(PyGetSetDescrObject),
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)getset_repr, /* tp_repr */
546 0, /* tp_as_number */
547 0, /* tp_as_sequence */
548 0, /* tp_as_mapping */
549 0, /* tp_hash */
550 0, /* 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 getset_getset, /* tp_getset */
566 0, /* tp_base */
567 0, /* tp_dict */
568 (descrgetfunc)getset_get, /* tp_descr_get */
569 (descrsetfunc)getset_set, /* tp_descr_set */
570 };
571
572 PyTypeObject PyWrapperDescr_Type = {
573 PyVarObject_HEAD_INIT(&PyType_Type, 0)
574 "wrapper_descriptor",
575 sizeof(PyWrapperDescrObject),
576 0,
577 (destructor)descr_dealloc, /* tp_dealloc */
578 0, /* tp_print */
579 0, /* tp_getattr */
580 0, /* tp_setattr */
581 0, /* tp_compare */
582 (reprfunc)wrapperdescr_repr, /* tp_repr */
583 0, /* tp_as_number */
584 0, /* tp_as_sequence */
585 0, /* tp_as_mapping */
586 0, /* tp_hash */
587 (ternaryfunc)wrapperdescr_call, /* tp_call */
588 0, /* tp_str */
589 PyObject_GenericGetAttr, /* tp_getattro */
590 0, /* tp_setattro */
591 0, /* tp_as_buffer */
592 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
593 0, /* tp_doc */
594 descr_traverse, /* tp_traverse */
595 0, /* tp_clear */
596 0, /* tp_richcompare */
597 0, /* tp_weaklistoffset */
598 0, /* tp_iter */
599 0, /* tp_iternext */
600 0, /* tp_methods */
601 descr_members, /* tp_members */
602 wrapperdescr_getset, /* tp_getset */
603 0, /* tp_base */
604 0, /* tp_dict */
605 (descrgetfunc)wrapperdescr_get, /* tp_descr_get */
606 0, /* tp_descr_set */
607 };
608
609 static PyDescrObject *
descr_new(PyTypeObject * descrtype,PyTypeObject * type,const char * name)610 descr_new(PyTypeObject *descrtype, PyTypeObject *type, const char *name)
611 {
612 PyDescrObject *descr;
613
614 descr = (PyDescrObject *)PyType_GenericAlloc(descrtype, 0);
615 if (descr != NULL) {
616 Py_XINCREF(type);
617 descr->d_type = type;
618 descr->d_name = PyString_InternFromString(name);
619 if (descr->d_name == NULL) {
620 Py_DECREF(descr);
621 descr = NULL;
622 }
623 }
624 return descr;
625 }
626
627 PyObject *
PyDescr_NewMethod(PyTypeObject * type,PyMethodDef * method)628 PyDescr_NewMethod(PyTypeObject *type, PyMethodDef *method)
629 {
630 PyMethodDescrObject *descr;
631
632 descr = (PyMethodDescrObject *)descr_new(&PyMethodDescr_Type,
633 type, method->ml_name);
634 if (descr != NULL)
635 descr->d_method = method;
636 return (PyObject *)descr;
637 }
638
639 PyObject *
PyDescr_NewClassMethod(PyTypeObject * type,PyMethodDef * method)640 PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)
641 {
642 PyMethodDescrObject *descr;
643
644 descr = (PyMethodDescrObject *)descr_new(&PyClassMethodDescr_Type,
645 type, method->ml_name);
646 if (descr != NULL)
647 descr->d_method = method;
648 return (PyObject *)descr;
649 }
650
651 PyObject *
PyDescr_NewMember(PyTypeObject * type,PyMemberDef * member)652 PyDescr_NewMember(PyTypeObject *type, PyMemberDef *member)
653 {
654 PyMemberDescrObject *descr;
655
656 descr = (PyMemberDescrObject *)descr_new(&PyMemberDescr_Type,
657 type, member->name);
658 if (descr != NULL)
659 descr->d_member = member;
660 return (PyObject *)descr;
661 }
662
663 PyObject *
PyDescr_NewGetSet(PyTypeObject * type,PyGetSetDef * getset)664 PyDescr_NewGetSet(PyTypeObject *type, PyGetSetDef *getset)
665 {
666 PyGetSetDescrObject *descr;
667
668 descr = (PyGetSetDescrObject *)descr_new(&PyGetSetDescr_Type,
669 type, getset->name);
670 if (descr != NULL)
671 descr->d_getset = getset;
672 return (PyObject *)descr;
673 }
674
675 PyObject *
PyDescr_NewWrapper(PyTypeObject * type,struct wrapperbase * base,void * wrapped)676 PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
677 {
678 PyWrapperDescrObject *descr;
679
680 descr = (PyWrapperDescrObject *)descr_new(&PyWrapperDescr_Type,
681 type, base->name);
682 if (descr != NULL) {
683 descr->d_base = base;
684 descr->d_wrapped = wrapped;
685 }
686 return (PyObject *)descr;
687 }
688
689
690 /* --- Readonly proxy for dictionaries (actually any mapping) --- */
691
692 /* This has no reason to be in this file except that adding new files is a
693 bit of a pain */
694
695 typedef struct {
696 PyObject_HEAD
697 PyObject *dict;
698 } proxyobject;
699
700 static Py_ssize_t
proxy_len(proxyobject * pp)701 proxy_len(proxyobject *pp)
702 {
703 return PyObject_Size(pp->dict);
704 }
705
706 static PyObject *
proxy_getitem(proxyobject * pp,PyObject * key)707 proxy_getitem(proxyobject *pp, PyObject *key)
708 {
709 return PyObject_GetItem(pp->dict, key);
710 }
711
712 static PyMappingMethods proxy_as_mapping = {
713 (lenfunc)proxy_len, /* mp_length */
714 (binaryfunc)proxy_getitem, /* mp_subscript */
715 0, /* mp_ass_subscript */
716 };
717
718 static int
proxy_contains(proxyobject * pp,PyObject * key)719 proxy_contains(proxyobject *pp, PyObject *key)
720 {
721 return PyDict_Contains(pp->dict, key);
722 }
723
724 static PySequenceMethods proxy_as_sequence = {
725 0, /* sq_length */
726 0, /* sq_concat */
727 0, /* sq_repeat */
728 0, /* sq_item */
729 0, /* sq_slice */
730 0, /* sq_ass_item */
731 0, /* sq_ass_slice */
732 (objobjproc)proxy_contains, /* sq_contains */
733 0, /* sq_inplace_concat */
734 0, /* sq_inplace_repeat */
735 };
736
737 static PyObject *
proxy_has_key(proxyobject * pp,PyObject * key)738 proxy_has_key(proxyobject *pp, PyObject *key)
739 {
740 int res = PyDict_Contains(pp->dict, key);
741 if (res < 0)
742 return NULL;
743 return PyBool_FromLong(res);
744 }
745
746 static PyObject *
proxy_get(proxyobject * pp,PyObject * args)747 proxy_get(proxyobject *pp, PyObject *args)
748 {
749 PyObject *key, *def = Py_None;
750
751 if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &def))
752 return NULL;
753 return PyObject_CallMethod(pp->dict, "get", "(OO)", key, def);
754 }
755
756 static PyObject *
proxy_keys(proxyobject * pp)757 proxy_keys(proxyobject *pp)
758 {
759 return PyMapping_Keys(pp->dict);
760 }
761
762 static PyObject *
proxy_values(proxyobject * pp)763 proxy_values(proxyobject *pp)
764 {
765 return PyMapping_Values(pp->dict);
766 }
767
768 static PyObject *
proxy_items(proxyobject * pp)769 proxy_items(proxyobject *pp)
770 {
771 return PyMapping_Items(pp->dict);
772 }
773
774 static PyObject *
proxy_iterkeys(proxyobject * pp)775 proxy_iterkeys(proxyobject *pp)
776 {
777 return PyObject_CallMethod(pp->dict, "iterkeys", NULL);
778 }
779
780 static PyObject *
proxy_itervalues(proxyobject * pp)781 proxy_itervalues(proxyobject *pp)
782 {
783 return PyObject_CallMethod(pp->dict, "itervalues", NULL);
784 }
785
786 static PyObject *
proxy_iteritems(proxyobject * pp)787 proxy_iteritems(proxyobject *pp)
788 {
789 return PyObject_CallMethod(pp->dict, "iteritems", NULL);
790 }
791 static PyObject *
proxy_copy(proxyobject * pp)792 proxy_copy(proxyobject *pp)
793 {
794 return PyObject_CallMethod(pp->dict, "copy", NULL);
795 }
796
797 static PyMethodDef proxy_methods[] = {
798 {"has_key", (PyCFunction)proxy_has_key, METH_O,
799 PyDoc_STR("D.has_key(k) -> True if D has a key k, else False")},
800 {"get", (PyCFunction)proxy_get, METH_VARARGS,
801 PyDoc_STR("D.get(k[,d]) -> D[k] if D.has_key(k), else d."
802 " d defaults to None.")},
803 {"keys", (PyCFunction)proxy_keys, METH_NOARGS,
804 PyDoc_STR("D.keys() -> list of D's keys")},
805 {"values", (PyCFunction)proxy_values, METH_NOARGS,
806 PyDoc_STR("D.values() -> list of D's values")},
807 {"items", (PyCFunction)proxy_items, METH_NOARGS,
808 PyDoc_STR("D.items() -> list of D's (key, value) pairs, as 2-tuples")},
809 {"iterkeys", (PyCFunction)proxy_iterkeys, METH_NOARGS,
810 PyDoc_STR("D.iterkeys() -> an iterator over the keys of D")},
811 {"itervalues",(PyCFunction)proxy_itervalues, METH_NOARGS,
812 PyDoc_STR("D.itervalues() -> an iterator over the values of D")},
813 {"iteritems", (PyCFunction)proxy_iteritems, METH_NOARGS,
814 PyDoc_STR("D.iteritems() ->"
815 " an iterator over the (key, value) items of D")},
816 {"copy", (PyCFunction)proxy_copy, METH_NOARGS,
817 PyDoc_STR("D.copy() -> a shallow copy of D")},
818 {0}
819 };
820
821 static void
proxy_dealloc(proxyobject * pp)822 proxy_dealloc(proxyobject *pp)
823 {
824 _PyObject_GC_UNTRACK(pp);
825 Py_DECREF(pp->dict);
826 PyObject_GC_Del(pp);
827 }
828
829 static PyObject *
proxy_getiter(proxyobject * pp)830 proxy_getiter(proxyobject *pp)
831 {
832 return PyObject_GetIter(pp->dict);
833 }
834
835 static PyObject *
proxy_str(proxyobject * pp)836 proxy_str(proxyobject *pp)
837 {
838 return PyObject_Str(pp->dict);
839 }
840
841 static PyObject *
proxy_repr(proxyobject * pp)842 proxy_repr(proxyobject *pp)
843 {
844 PyObject *dictrepr;
845 PyObject *result;
846
847 dictrepr = PyObject_Repr(pp->dict);
848 if (dictrepr == NULL)
849 return NULL;
850 result = PyString_FromFormat("dict_proxy(%s)", PyString_AS_STRING(dictrepr));
851 Py_DECREF(dictrepr);
852 return result;
853 }
854
855 static int
proxy_traverse(PyObject * self,visitproc visit,void * arg)856 proxy_traverse(PyObject *self, visitproc visit, void *arg)
857 {
858 proxyobject *pp = (proxyobject *)self;
859 Py_VISIT(pp->dict);
860 return 0;
861 }
862
863 static int
proxy_compare(proxyobject * v,PyObject * w)864 proxy_compare(proxyobject *v, PyObject *w)
865 {
866 return PyObject_Compare(v->dict, w);
867 }
868
869 static PyObject *
proxy_richcompare(proxyobject * v,PyObject * w,int op)870 proxy_richcompare(proxyobject *v, PyObject *w, int op)
871 {
872 return PyObject_RichCompare(v->dict, w, op);
873 }
874
875 PyTypeObject PyDictProxy_Type = {
876 PyVarObject_HEAD_INIT(&PyType_Type, 0)
877 "dictproxy", /* tp_name */
878 sizeof(proxyobject), /* tp_basicsize */
879 0, /* tp_itemsize */
880 /* methods */
881 (destructor)proxy_dealloc, /* tp_dealloc */
882 0, /* tp_print */
883 0, /* tp_getattr */
884 0, /* tp_setattr */
885 (cmpfunc)proxy_compare, /* tp_compare */
886 (reprfunc)proxy_repr, /* tp_repr */
887 0, /* tp_as_number */
888 &proxy_as_sequence, /* tp_as_sequence */
889 &proxy_as_mapping, /* tp_as_mapping */
890 0, /* tp_hash */
891 0, /* tp_call */
892 (reprfunc)proxy_str, /* tp_str */
893 PyObject_GenericGetAttr, /* tp_getattro */
894 0, /* tp_setattro */
895 0, /* tp_as_buffer */
896 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
897 0, /* tp_doc */
898 proxy_traverse, /* tp_traverse */
899 0, /* tp_clear */
900 (richcmpfunc)proxy_richcompare, /* tp_richcompare */
901 0, /* tp_weaklistoffset */
902 (getiterfunc)proxy_getiter, /* tp_iter */
903 0, /* tp_iternext */
904 proxy_methods, /* tp_methods */
905 0, /* tp_members */
906 0, /* tp_getset */
907 0, /* tp_base */
908 0, /* tp_dict */
909 0, /* tp_descr_get */
910 0, /* tp_descr_set */
911 };
912
913 PyObject *
PyDictProxy_New(PyObject * dict)914 PyDictProxy_New(PyObject *dict)
915 {
916 proxyobject *pp;
917
918 pp = PyObject_GC_New(proxyobject, &PyDictProxy_Type);
919 if (pp != NULL) {
920 Py_INCREF(dict);
921 pp->dict = dict;
922 _PyObject_GC_TRACK(pp);
923 }
924 return (PyObject *)pp;
925 }
926
927
928 /* --- Wrapper object for "slot" methods --- */
929
930 /* This has no reason to be in this file except that adding new files is a
931 bit of a pain */
932
933 typedef struct {
934 PyObject_HEAD
935 PyWrapperDescrObject *descr;
936 PyObject *self;
937 } wrapperobject;
938
939 static void
wrapper_dealloc(wrapperobject * wp)940 wrapper_dealloc(wrapperobject *wp)
941 {
942 PyObject_GC_UnTrack(wp);
943 Py_TRASHCAN_SAFE_BEGIN(wp)
944 Py_XDECREF(wp->descr);
945 Py_XDECREF(wp->self);
946 PyObject_GC_Del(wp);
947 Py_TRASHCAN_SAFE_END(wp)
948 }
949
950 static int
wrapper_compare(wrapperobject * a,wrapperobject * b)951 wrapper_compare(wrapperobject *a, wrapperobject *b)
952 {
953 if (a->descr == b->descr)
954 return PyObject_Compare(a->self, b->self);
955 else
956 return (a->descr < b->descr) ? -1 : 1;
957 }
958
959 static long
wrapper_hash(wrapperobject * wp)960 wrapper_hash(wrapperobject *wp)
961 {
962 int x, y;
963 x = _Py_HashPointer(wp->descr);
964 if (x == -1)
965 return -1;
966 y = PyObject_Hash(wp->self);
967 if (y == -1)
968 return -1;
969 x = x ^ y;
970 if (x == -1)
971 x = -2;
972 return x;
973 }
974
975 static PyObject *
wrapper_repr(wrapperobject * wp)976 wrapper_repr(wrapperobject *wp)
977 {
978 return PyString_FromFormat("<method-wrapper '%s' of %s object at %p>",
979 wp->descr->d_base->name,
980 wp->self->ob_type->tp_name,
981 wp->self);
982 }
983
984 static PyMemberDef wrapper_members[] = {
985 {"__self__", T_OBJECT, offsetof(wrapperobject, self), READONLY},
986 {0}
987 };
988
989 static PyObject *
wrapper_objclass(wrapperobject * wp)990 wrapper_objclass(wrapperobject *wp)
991 {
992 PyObject *c = (PyObject *)wp->descr->d_type;
993
994 Py_INCREF(c);
995 return c;
996 }
997
998 static PyObject *
wrapper_name(wrapperobject * wp)999 wrapper_name(wrapperobject *wp)
1000 {
1001 char *s = wp->descr->d_base->name;
1002
1003 return PyString_FromString(s);
1004 }
1005
1006 static PyObject *
wrapper_doc(wrapperobject * wp)1007 wrapper_doc(wrapperobject *wp)
1008 {
1009 char *s = wp->descr->d_base->doc;
1010
1011 if (s == NULL) {
1012 Py_INCREF(Py_None);
1013 return Py_None;
1014 }
1015 else {
1016 return PyString_FromString(s);
1017 }
1018 }
1019
1020 static PyGetSetDef wrapper_getsets[] = {
1021 {"__objclass__", (getter)wrapper_objclass},
1022 {"__name__", (getter)wrapper_name},
1023 {"__doc__", (getter)wrapper_doc},
1024 {0}
1025 };
1026
1027 static PyObject *
wrapper_call(wrapperobject * wp,PyObject * args,PyObject * kwds)1028 wrapper_call(wrapperobject *wp, PyObject *args, PyObject *kwds)
1029 {
1030 wrapperfunc wrapper = wp->descr->d_base->wrapper;
1031 PyObject *self = wp->self;
1032
1033 if (wp->descr->d_base->flags & PyWrapperFlag_KEYWORDS) {
1034 wrapperfunc_kwds wk = (wrapperfunc_kwds)wrapper;
1035 return (*wk)(self, args, wp->descr->d_wrapped, kwds);
1036 }
1037
1038 if (kwds != NULL && (!PyDict_Check(kwds) || PyDict_Size(kwds) != 0)) {
1039 PyErr_Format(PyExc_TypeError,
1040 "wrapper %s doesn't take keyword arguments",
1041 wp->descr->d_base->name);
1042 return NULL;
1043 }
1044 return (*wrapper)(self, args, wp->descr->d_wrapped);
1045 }
1046
1047 static int
wrapper_traverse(PyObject * self,visitproc visit,void * arg)1048 wrapper_traverse(PyObject *self, visitproc visit, void *arg)
1049 {
1050 wrapperobject *wp = (wrapperobject *)self;
1051 Py_VISIT(wp->descr);
1052 Py_VISIT(wp->self);
1053 return 0;
1054 }
1055
1056 static PyTypeObject wrappertype = {
1057 PyVarObject_HEAD_INIT(&PyType_Type, 0)
1058 "method-wrapper", /* tp_name */
1059 sizeof(wrapperobject), /* tp_basicsize */
1060 0, /* tp_itemsize */
1061 /* methods */
1062 (destructor)wrapper_dealloc, /* tp_dealloc */
1063 0, /* tp_print */
1064 0, /* tp_getattr */
1065 0, /* tp_setattr */
1066 (cmpfunc)wrapper_compare, /* tp_compare */
1067 (reprfunc)wrapper_repr, /* tp_repr */
1068 0, /* tp_as_number */
1069 0, /* tp_as_sequence */
1070 0, /* tp_as_mapping */
1071 (hashfunc)wrapper_hash, /* tp_hash */
1072 (ternaryfunc)wrapper_call, /* tp_call */
1073 0, /* tp_str */
1074 PyObject_GenericGetAttr, /* tp_getattro */
1075 0, /* tp_setattro */
1076 0, /* tp_as_buffer */
1077 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
1078 0, /* tp_doc */
1079 wrapper_traverse, /* tp_traverse */
1080 0, /* tp_clear */
1081 0, /* tp_richcompare */
1082 0, /* tp_weaklistoffset */
1083 0, /* tp_iter */
1084 0, /* tp_iternext */
1085 0, /* tp_methods */
1086 wrapper_members, /* tp_members */
1087 wrapper_getsets, /* tp_getset */
1088 0, /* tp_base */
1089 0, /* tp_dict */
1090 0, /* tp_descr_get */
1091 0, /* tp_descr_set */
1092 };
1093
1094 PyObject *
PyWrapper_New(PyObject * d,PyObject * self)1095 PyWrapper_New(PyObject *d, PyObject *self)
1096 {
1097 wrapperobject *wp;
1098 PyWrapperDescrObject *descr;
1099
1100 assert(PyObject_TypeCheck(d, &PyWrapperDescr_Type));
1101 descr = (PyWrapperDescrObject *)d;
1102 assert(_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
1103 (PyObject *)(descr->d_type)));
1104
1105 wp = PyObject_GC_New(wrapperobject, &wrappertype);
1106 if (wp != NULL) {
1107 Py_INCREF(descr);
1108 wp->descr = descr;
1109 Py_INCREF(self);
1110 wp->self = self;
1111 _PyObject_GC_TRACK(wp);
1112 }
1113 return (PyObject *)wp;
1114 }
1115
1116
1117 /* A built-in 'property' type */
1118
1119 /*
1120 class property(object):
1121
1122 def __init__(self, fget=None, fset=None, fdel=None, doc=None):
1123 if doc is None and fget is not None and hasattr(fget, "__doc__"):
1124 doc = fget.__doc__
1125 self.__get = fget
1126 self.__set = fset
1127 self.__del = fdel
1128 self.__doc__ = doc
1129
1130 def __get__(self, inst, type=None):
1131 if inst is None:
1132 return self
1133 if self.__get is None:
1134 raise AttributeError, "unreadable attribute"
1135 return self.__get(inst)
1136
1137 def __set__(self, inst, value):
1138 if self.__set is None:
1139 raise AttributeError, "can't set attribute"
1140 return self.__set(inst, value)
1141
1142 def __delete__(self, inst):
1143 if self.__del is None:
1144 raise AttributeError, "can't delete attribute"
1145 return self.__del(inst)
1146
1147 */
1148
1149 typedef struct {
1150 PyObject_HEAD
1151 PyObject *prop_get;
1152 PyObject *prop_set;
1153 PyObject *prop_del;
1154 PyObject *prop_doc;
1155 int getter_doc;
1156 } propertyobject;
1157
1158 static PyObject * property_copy(PyObject *, PyObject *, PyObject *,
1159 PyObject *);
1160
1161 static PyMemberDef property_members[] = {
1162 {"fget", T_OBJECT, offsetof(propertyobject, prop_get), READONLY},
1163 {"fset", T_OBJECT, offsetof(propertyobject, prop_set), READONLY},
1164 {"fdel", T_OBJECT, offsetof(propertyobject, prop_del), READONLY},
1165 {"__doc__", T_OBJECT, offsetof(propertyobject, prop_doc), READONLY},
1166 {0}
1167 };
1168
1169
1170 PyDoc_STRVAR(getter_doc,
1171 "Descriptor to change the getter on a property.");
1172
1173 static PyObject *
property_getter(PyObject * self,PyObject * getter)1174 property_getter(PyObject *self, PyObject *getter)
1175 {
1176 return property_copy(self, getter, NULL, NULL);
1177 }
1178
1179
1180 PyDoc_STRVAR(setter_doc,
1181 "Descriptor to change the setter on a property.");
1182
1183 static PyObject *
property_setter(PyObject * self,PyObject * setter)1184 property_setter(PyObject *self, PyObject *setter)
1185 {
1186 return property_copy(self, NULL, setter, NULL);
1187 }
1188
1189
1190 PyDoc_STRVAR(deleter_doc,
1191 "Descriptor to change the deleter on a property.");
1192
1193 static PyObject *
property_deleter(PyObject * self,PyObject * deleter)1194 property_deleter(PyObject *self, PyObject *deleter)
1195 {
1196 return property_copy(self, NULL, NULL, deleter);
1197 }
1198
1199
1200 static PyMethodDef property_methods[] = {
1201 {"getter", property_getter, METH_O, getter_doc},
1202 {"setter", property_setter, METH_O, setter_doc},
1203 {"deleter", property_deleter, METH_O, deleter_doc},
1204 {0}
1205 };
1206
1207
1208 static void
property_dealloc(PyObject * self)1209 property_dealloc(PyObject *self)
1210 {
1211 propertyobject *gs = (propertyobject *)self;
1212
1213 _PyObject_GC_UNTRACK(self);
1214 Py_XDECREF(gs->prop_get);
1215 Py_XDECREF(gs->prop_set);
1216 Py_XDECREF(gs->prop_del);
1217 Py_XDECREF(gs->prop_doc);
1218 self->ob_type->tp_free(self);
1219 }
1220
1221 static PyObject *
property_descr_get(PyObject * self,PyObject * obj,PyObject * type)1222 property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
1223 {
1224 propertyobject *gs = (propertyobject *)self;
1225
1226 if (obj == NULL || obj == Py_None) {
1227 Py_INCREF(self);
1228 return self;
1229 }
1230 if (gs->prop_get == NULL) {
1231 PyErr_SetString(PyExc_AttributeError, "unreadable attribute");
1232 return NULL;
1233 }
1234 return PyObject_CallFunction(gs->prop_get, "(O)", obj);
1235 }
1236
1237 static int
property_descr_set(PyObject * self,PyObject * obj,PyObject * value)1238 property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
1239 {
1240 propertyobject *gs = (propertyobject *)self;
1241 PyObject *func, *res;
1242
1243 if (value == NULL)
1244 func = gs->prop_del;
1245 else
1246 func = gs->prop_set;
1247 if (func == NULL) {
1248 PyErr_SetString(PyExc_AttributeError,
1249 value == NULL ?
1250 "can't delete attribute" :
1251 "can't set attribute");
1252 return -1;
1253 }
1254 if (value == NULL)
1255 res = PyObject_CallFunction(func, "(O)", obj);
1256 else
1257 res = PyObject_CallFunction(func, "(OO)", obj, value);
1258 if (res == NULL)
1259 return -1;
1260 Py_DECREF(res);
1261 return 0;
1262 }
1263
1264 static PyObject *
property_copy(PyObject * old,PyObject * get,PyObject * set,PyObject * del)1265 property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del)
1266 {
1267 propertyobject *pold = (propertyobject *)old;
1268 PyObject *new, *type, *doc;
1269
1270 type = PyObject_Type(old);
1271 if (type == NULL)
1272 return NULL;
1273
1274 if (get == NULL || get == Py_None) {
1275 Py_XDECREF(get);
1276 get = pold->prop_get ? pold->prop_get : Py_None;
1277 }
1278 if (set == NULL || set == Py_None) {
1279 Py_XDECREF(set);
1280 set = pold->prop_set ? pold->prop_set : Py_None;
1281 }
1282 if (del == NULL || del == Py_None) {
1283 Py_XDECREF(del);
1284 del = pold->prop_del ? pold->prop_del : Py_None;
1285 }
1286 if (pold->getter_doc && get != Py_None) {
1287 /* make _init use __doc__ from getter */
1288 doc = Py_None;
1289 }
1290 else {
1291 doc = pold->prop_doc ? pold->prop_doc : Py_None;
1292 }
1293
1294 new = PyObject_CallFunction(type, "OOOO", get, set, del, doc);
1295 Py_DECREF(type);
1296 if (new == NULL)
1297 return NULL;
1298 return new;
1299 }
1300
1301 static int
property_init(PyObject * self,PyObject * args,PyObject * kwds)1302 property_init(PyObject *self, PyObject *args, PyObject *kwds)
1303 {
1304 PyObject *get = NULL, *set = NULL, *del = NULL, *doc = NULL;
1305 static char *kwlist[] = {"fget", "fset", "fdel", "doc", 0};
1306 propertyobject *prop = (propertyobject *)self;
1307
1308 if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOOO:property",
1309 kwlist, &get, &set, &del, &doc))
1310 return -1;
1311
1312 if (get == Py_None)
1313 get = NULL;
1314 if (set == Py_None)
1315 set = NULL;
1316 if (del == Py_None)
1317 del = NULL;
1318
1319 Py_XINCREF(get);
1320 Py_XINCREF(set);
1321 Py_XINCREF(del);
1322 Py_XINCREF(doc);
1323
1324 prop->prop_get = get;
1325 prop->prop_set = set;
1326 prop->prop_del = del;
1327 prop->prop_doc = doc;
1328 prop->getter_doc = 0;
1329
1330 /* if no docstring given and the getter has one, use that one */
1331 if ((doc == NULL || doc == Py_None) && get != NULL) {
1332 PyObject *get_doc = PyObject_GetAttrString(get, "__doc__");
1333 if (get_doc) {
1334 if (Py_TYPE(self) == &PyProperty_Type) {
1335 Py_XSETREF(prop->prop_doc, get_doc);
1336 }
1337 else {
1338 /* If this is a property subclass, put __doc__
1339 in dict of the subclass instance instead,
1340 otherwise it gets shadowed by __doc__ in the
1341 class's dict. */
1342 int err = PyObject_SetAttrString(self, "__doc__", get_doc);
1343 Py_DECREF(get_doc);
1344 if (err < 0)
1345 return -1;
1346 }
1347 prop->getter_doc = 1;
1348 }
1349 else if (PyErr_ExceptionMatches(PyExc_Exception)) {
1350 PyErr_Clear();
1351 }
1352 else {
1353 return -1;
1354 }
1355 }
1356
1357 return 0;
1358 }
1359
1360 PyDoc_STRVAR(property_doc,
1361 "property(fget=None, fset=None, fdel=None, doc=None) -> property attribute\n"
1362 "\n"
1363 "fget is a function to be used for getting an attribute value, and likewise\n"
1364 "fset is a function for setting, and fdel a function for del'ing, an\n"
1365 "attribute. Typical use is to define a managed attribute x:\n\n"
1366 "class C(object):\n"
1367 " def getx(self): return self._x\n"
1368 " def setx(self, value): self._x = value\n"
1369 " def delx(self): del self._x\n"
1370 " x = property(getx, setx, delx, \"I'm the 'x' property.\")\n"
1371 "\n"
1372 "Decorators make defining new properties or modifying existing ones easy:\n\n"
1373 "class C(object):\n"
1374 " @property\n"
1375 " def x(self):\n"
1376 " \"I am the 'x' property.\"\n"
1377 " return self._x\n"
1378 " @x.setter\n"
1379 " def x(self, value):\n"
1380 " self._x = value\n"
1381 " @x.deleter\n"
1382 " def x(self):\n"
1383 " del self._x\n"
1384 );
1385
1386 static int
property_traverse(PyObject * self,visitproc visit,void * arg)1387 property_traverse(PyObject *self, visitproc visit, void *arg)
1388 {
1389 propertyobject *pp = (propertyobject *)self;
1390 Py_VISIT(pp->prop_get);
1391 Py_VISIT(pp->prop_set);
1392 Py_VISIT(pp->prop_del);
1393 Py_VISIT(pp->prop_doc);
1394 return 0;
1395 }
1396
1397 PyTypeObject PyProperty_Type = {
1398 PyVarObject_HEAD_INIT(&PyType_Type, 0)
1399 "property", /* tp_name */
1400 sizeof(propertyobject), /* tp_basicsize */
1401 0, /* tp_itemsize */
1402 /* methods */
1403 property_dealloc, /* tp_dealloc */
1404 0, /* tp_print */
1405 0, /* tp_getattr */
1406 0, /* tp_setattr */
1407 0, /* tp_compare */
1408 0, /* tp_repr */
1409 0, /* tp_as_number */
1410 0, /* tp_as_sequence */
1411 0, /* tp_as_mapping */
1412 0, /* tp_hash */
1413 0, /* tp_call */
1414 0, /* tp_str */
1415 PyObject_GenericGetAttr, /* tp_getattro */
1416 0, /* tp_setattro */
1417 0, /* tp_as_buffer */
1418 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
1419 Py_TPFLAGS_BASETYPE, /* tp_flags */
1420 property_doc, /* tp_doc */
1421 property_traverse, /* tp_traverse */
1422 0, /* tp_clear */
1423 0, /* tp_richcompare */
1424 0, /* tp_weaklistoffset */
1425 0, /* tp_iter */
1426 0, /* tp_iternext */
1427 property_methods, /* tp_methods */
1428 property_members, /* tp_members */
1429 0, /* tp_getset */
1430 0, /* tp_base */
1431 0, /* tp_dict */
1432 property_descr_get, /* tp_descr_get */
1433 property_descr_set, /* tp_descr_set */
1434 0, /* tp_dictoffset */
1435 property_init, /* tp_init */
1436 PyType_GenericAlloc, /* tp_alloc */
1437 PyType_GenericNew, /* tp_new */
1438 PyObject_GC_Del, /* tp_free */
1439 };
1440