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/Objects/descrobject.c

https://gitlab.com/unofficial-mirrors/cpython
C | 1491 lines | 1269 code | 169 blank | 53 comment | 150 complexity | 2362ba6609b2962d5fc978b9e2324825 MD5 | raw file
   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
   6static void
   7descr_dealloc(PyDescrObject *descr)
   8{
   9    _PyObject_GC_UNTRACK(descr);
  10    Py_XDECREF(descr->d_type);
  11    Py_XDECREF(descr->d_name);
  12    Py_XDECREF(descr->d_qualname);
  13    PyObject_GC_Del(descr);
  14}
  15
  16static PyObject *
  17descr_name(PyDescrObject *descr)
  18{
  19    if (descr->d_name != NULL && PyUnicode_Check(descr->d_name))
  20        return descr->d_name;
  21    return NULL;
  22}
  23
  24static PyObject *
  25descr_repr(PyDescrObject *descr, const char *format)
  26{
  27    PyObject *name = NULL;
  28    if (descr->d_name != NULL && PyUnicode_Check(descr->d_name))
  29        name = descr->d_name;
  30
  31    return PyUnicode_FromFormat(format, name, "?", descr->d_type->tp_name);
  32}
  33
  34static PyObject *
  35method_repr(PyMethodDescrObject *descr)
  36{
  37    return descr_repr((PyDescrObject *)descr,
  38                      "<method '%V' of '%s' objects>");
  39}
  40
  41static PyObject *
  42member_repr(PyMemberDescrObject *descr)
  43{
  44    return descr_repr((PyDescrObject *)descr,
  45                      "<member '%V' of '%s' objects>");
  46}
  47
  48static PyObject *
  49getset_repr(PyGetSetDescrObject *descr)
  50{
  51    return descr_repr((PyDescrObject *)descr,
  52                      "<attribute '%V' of '%s' objects>");
  53}
  54
  55static PyObject *
  56wrapperdescr_repr(PyWrapperDescrObject *descr)
  57{
  58    return descr_repr((PyDescrObject *)descr,
  59                      "<slot wrapper '%V' of '%s' objects>");
  60}
  61
  62static int
  63descr_check(PyDescrObject *descr, PyObject *obj, PyObject **pres)
  64{
  65    if (obj == NULL) {
  66        Py_INCREF(descr);
  67        *pres = (PyObject *)descr;
  68        return 1;
  69    }
  70    if (!PyObject_TypeCheck(obj, descr->d_type)) {
  71        PyErr_Format(PyExc_TypeError,
  72                     "descriptor '%V' for '%s' objects "
  73                     "doesn't apply to '%s' object",
  74                     descr_name((PyDescrObject *)descr), "?",
  75                     descr->d_type->tp_name,
  76                     obj->ob_type->tp_name);
  77        *pres = NULL;
  78        return 1;
  79    }
  80    return 0;
  81}
  82
  83static PyObject *
  84classmethod_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
  85{
  86    /* Ensure a valid type.  Class methods ignore obj. */
  87    if (type == NULL) {
  88        if (obj != NULL)
  89            type = (PyObject *)obj->ob_type;
  90        else {
  91            /* Wot - no type?! */
  92            PyErr_Format(PyExc_TypeError,
  93                         "descriptor '%V' for type '%s' "
  94                         "needs either an object or a type",
  95                         descr_name((PyDescrObject *)descr), "?",
  96                         PyDescr_TYPE(descr)->tp_name);
  97            return NULL;
  98        }
  99    }
 100    if (!PyType_Check(type)) {
 101        PyErr_Format(PyExc_TypeError,
 102                     "descriptor '%V' for type '%s' "
 103                     "needs a type, not a '%s' as arg 2",
 104                     descr_name((PyDescrObject *)descr), "?",
 105                     PyDescr_TYPE(descr)->tp_name,
 106                     type->ob_type->tp_name);
 107        return NULL;
 108    }
 109    if (!PyType_IsSubtype((PyTypeObject *)type, PyDescr_TYPE(descr))) {
 110        PyErr_Format(PyExc_TypeError,
 111                     "descriptor '%V' for type '%s' "
 112                     "doesn't apply to type '%s'",
 113                     descr_name((PyDescrObject *)descr), "?",
 114                     PyDescr_TYPE(descr)->tp_name,
 115                     ((PyTypeObject *)type)->tp_name);
 116        return NULL;
 117    }
 118    return PyCFunction_NewEx(descr->d_method, type, NULL);
 119}
 120
 121static PyObject *
 122method_get(PyMethodDescrObject *descr, PyObject *obj, PyObject *type)
 123{
 124    PyObject *res;
 125
 126    if (descr_check((PyDescrObject *)descr, obj, &res))
 127        return res;
 128    return PyCFunction_NewEx(descr->d_method, obj, NULL);
 129}
 130
 131static PyObject *
 132member_get(PyMemberDescrObject *descr, PyObject *obj, PyObject *type)
 133{
 134    PyObject *res;
 135
 136    if (descr_check((PyDescrObject *)descr, obj, &res))
 137        return res;
 138    return PyMember_GetOne((char *)obj, descr->d_member);
 139}
 140
 141static PyObject *
 142getset_get(PyGetSetDescrObject *descr, PyObject *obj, PyObject *type)
 143{
 144    PyObject *res;
 145
 146    if (descr_check((PyDescrObject *)descr, obj, &res))
 147        return res;
 148    if (descr->d_getset->get != NULL)
 149        return descr->d_getset->get(obj, descr->d_getset->closure);
 150    PyErr_Format(PyExc_AttributeError,
 151                 "attribute '%V' of '%.100s' objects is not readable",
 152                 descr_name((PyDescrObject *)descr), "?",
 153                 PyDescr_TYPE(descr)->tp_name);
 154    return NULL;
 155}
 156
 157static PyObject *
 158wrapperdescr_get(PyWrapperDescrObject *descr, PyObject *obj, PyObject *type)
 159{
 160    PyObject *res;
 161
 162    if (descr_check((PyDescrObject *)descr, obj, &res))
 163        return res;
 164    return PyWrapper_New((PyObject *)descr, obj);
 165}
 166
 167static int
 168descr_setcheck(PyDescrObject *descr, PyObject *obj, PyObject *value,
 169               int *pres)
 170{
 171    assert(obj != NULL);
 172    if (!PyObject_TypeCheck(obj, descr->d_type)) {
 173        PyErr_Format(PyExc_TypeError,
 174                     "descriptor '%V' for '%.100s' objects "
 175                     "doesn't apply to '%.100s' object",
 176                     descr_name(descr), "?",
 177                     descr->d_type->tp_name,
 178                     obj->ob_type->tp_name);
 179        *pres = -1;
 180        return 1;
 181    }
 182    return 0;
 183}
 184
 185static int
 186member_set(PyMemberDescrObject *descr, PyObject *obj, PyObject *value)
 187{
 188    int res;
 189
 190    if (descr_setcheck((PyDescrObject *)descr, obj, value, &res))
 191        return res;
 192    return PyMember_SetOne((char *)obj, descr->d_member, value);
 193}
 194
 195static int
 196getset_set(PyGetSetDescrObject *descr, PyObject *obj, PyObject *value)
 197{
 198    int res;
 199
 200    if (descr_setcheck((PyDescrObject *)descr, obj, value, &res))
 201        return res;
 202    if (descr->d_getset->set != NULL)
 203        return descr->d_getset->set(obj, value,
 204                                    descr->d_getset->closure);
 205    PyErr_Format(PyExc_AttributeError,
 206                 "attribute '%V' of '%.100s' objects is not writable",
 207                 descr_name((PyDescrObject *)descr), "?",
 208                 PyDescr_TYPE(descr)->tp_name);
 209    return -1;
 210}
 211
 212static PyObject *
 213methoddescr_call(PyMethodDescrObject *descr, PyObject *args, PyObject *kwargs)
 214{
 215    Py_ssize_t nargs;
 216    PyObject *self, *result;
 217
 218    /* Make sure that the first argument is acceptable as 'self' */
 219    assert(PyTuple_Check(args));
 220    nargs = PyTuple_GET_SIZE(args);
 221    if (nargs < 1) {
 222        PyErr_Format(PyExc_TypeError,
 223                     "descriptor '%V' of '%.100s' "
 224                     "object needs an argument",
 225                     descr_name((PyDescrObject *)descr), "?",
 226                     PyDescr_TYPE(descr)->tp_name);
 227        return NULL;
 228    }
 229    self = PyTuple_GET_ITEM(args, 0);
 230    if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
 231                                  (PyObject *)PyDescr_TYPE(descr))) {
 232        PyErr_Format(PyExc_TypeError,
 233                     "descriptor '%V' "
 234                     "requires a '%.100s' object "
 235                     "but received a '%.100s'",
 236                     descr_name((PyDescrObject *)descr), "?",
 237                     PyDescr_TYPE(descr)->tp_name,
 238                     self->ob_type->tp_name);
 239        return NULL;
 240    }
 241
 242    result = _PyMethodDef_RawFastCallDict(descr->d_method, self,
 243                                          &PyTuple_GET_ITEM(args, 1), nargs - 1,
 244                                          kwargs);
 245    result = _Py_CheckFunctionResult((PyObject *)descr, result, NULL);
 246    return result;
 247}
 248
 249// same to methoddescr_call(), but use FASTCALL convention.
 250PyObject *
 251_PyMethodDescr_FastCallKeywords(PyObject *descrobj,
 252                                PyObject **args, Py_ssize_t nargs,
 253                                PyObject *kwnames)
 254{
 255    assert(Py_TYPE(descrobj) == &PyMethodDescr_Type);
 256    PyMethodDescrObject *descr = (PyMethodDescrObject *)descrobj;
 257    PyObject *self, *result;
 258
 259    /* Make sure that the first argument is acceptable as 'self' */
 260    if (nargs < 1) {
 261        PyErr_Format(PyExc_TypeError,
 262                     "descriptor '%V' of '%.100s' "
 263                     "object needs an argument",
 264                     descr_name((PyDescrObject *)descr), "?",
 265                     PyDescr_TYPE(descr)->tp_name);
 266        return NULL;
 267    }
 268    self = args[0];
 269    if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
 270                                  (PyObject *)PyDescr_TYPE(descr))) {
 271        PyErr_Format(PyExc_TypeError,
 272                     "descriptor '%V' "
 273                     "requires a '%.100s' object "
 274                     "but received a '%.100s'",
 275                     descr_name((PyDescrObject *)descr), "?",
 276                     PyDescr_TYPE(descr)->tp_name,
 277                     self->ob_type->tp_name);
 278        return NULL;
 279    }
 280
 281    result = _PyMethodDef_RawFastCallKeywords(descr->d_method, self,
 282                                              args+1, nargs-1, kwnames);
 283    result = _Py_CheckFunctionResult((PyObject *)descr, result, NULL);
 284    return result;
 285}
 286
 287static PyObject *
 288classmethoddescr_call(PyMethodDescrObject *descr, PyObject *args,
 289                      PyObject *kwds)
 290{
 291    Py_ssize_t argc;
 292    PyObject *self, *func, *result, **stack;
 293
 294    /* Make sure that the first argument is acceptable as 'self' */
 295    assert(PyTuple_Check(args));
 296    argc = PyTuple_GET_SIZE(args);
 297    if (argc < 1) {
 298        PyErr_Format(PyExc_TypeError,
 299                     "descriptor '%V' of '%.100s' "
 300                     "object needs an argument",
 301                     descr_name((PyDescrObject *)descr), "?",
 302                     PyDescr_TYPE(descr)->tp_name);
 303        return NULL;
 304    }
 305    self = PyTuple_GET_ITEM(args, 0);
 306    if (!PyType_Check(self)) {
 307        PyErr_Format(PyExc_TypeError,
 308                     "descriptor '%V' requires a type "
 309                     "but received a '%.100s'",
 310                     descr_name((PyDescrObject *)descr), "?",
 311                     PyDescr_TYPE(descr)->tp_name,
 312                     self->ob_type->tp_name);
 313        return NULL;
 314    }
 315    if (!PyType_IsSubtype((PyTypeObject *)self, PyDescr_TYPE(descr))) {
 316        PyErr_Format(PyExc_TypeError,
 317                     "descriptor '%V' "
 318                     "requires a subtype of '%.100s' "
 319                     "but received '%.100s",
 320                     descr_name((PyDescrObject *)descr), "?",
 321                     PyDescr_TYPE(descr)->tp_name,
 322                     self->ob_type->tp_name);
 323        return NULL;
 324    }
 325
 326    func = PyCFunction_NewEx(descr->d_method, self, NULL);
 327    if (func == NULL)
 328        return NULL;
 329    stack = &PyTuple_GET_ITEM(args, 1);
 330    result = _PyObject_FastCallDict(func, stack, argc - 1, kwds);
 331    Py_DECREF(func);
 332    return result;
 333}
 334
 335static PyObject *
 336wrapperdescr_call(PyWrapperDescrObject *descr, PyObject *args, PyObject *kwds)
 337{
 338    Py_ssize_t argc;
 339    PyObject *self, *func, *result, **stack;
 340
 341    /* Make sure that the first argument is acceptable as 'self' */
 342    assert(PyTuple_Check(args));
 343    argc = PyTuple_GET_SIZE(args);
 344    if (argc < 1) {
 345        PyErr_Format(PyExc_TypeError,
 346                     "descriptor '%V' of '%.100s' "
 347                     "object needs an argument",
 348                     descr_name((PyDescrObject *)descr), "?",
 349                     PyDescr_TYPE(descr)->tp_name);
 350        return NULL;
 351    }
 352    self = PyTuple_GET_ITEM(args, 0);
 353    if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
 354                                  (PyObject *)PyDescr_TYPE(descr))) {
 355        PyErr_Format(PyExc_TypeError,
 356                     "descriptor '%V' "
 357                     "requires a '%.100s' object "
 358                     "but received a '%.100s'",
 359                     descr_name((PyDescrObject *)descr), "?",
 360                     PyDescr_TYPE(descr)->tp_name,
 361                     self->ob_type->tp_name);
 362        return NULL;
 363    }
 364
 365    func = PyWrapper_New((PyObject *)descr, self);
 366    if (func == NULL)
 367        return NULL;
 368
 369    stack = &PyTuple_GET_ITEM(args, 1);
 370    result = _PyObject_FastCallDict(func, stack, argc - 1, kwds);
 371    Py_DECREF(func);
 372    return result;
 373}
 374
 375static PyObject *
 376method_get_doc(PyMethodDescrObject *descr, void *closure)
 377{
 378    return _PyType_GetDocFromInternalDoc(descr->d_method->ml_name, descr->d_method->ml_doc);
 379}
 380
 381static PyObject *
 382method_get_text_signature(PyMethodDescrObject *descr, void *closure)
 383{
 384    return _PyType_GetTextSignatureFromInternalDoc(descr->d_method->ml_name, descr->d_method->ml_doc);
 385}
 386
 387static PyObject *
 388calculate_qualname(PyDescrObject *descr)
 389{
 390    PyObject *type_qualname, *res;
 391    _Py_IDENTIFIER(__qualname__);
 392
 393    if (descr->d_name == NULL || !PyUnicode_Check(descr->d_name)) {
 394        PyErr_SetString(PyExc_TypeError,
 395                        "<descriptor>.__name__ is not a unicode object");
 396        return NULL;
 397    }
 398
 399    type_qualname = _PyObject_GetAttrId((PyObject *)descr->d_type,
 400                                        &PyId___qualname__);
 401    if (type_qualname == NULL)
 402        return NULL;
 403
 404    if (!PyUnicode_Check(type_qualname)) {
 405        PyErr_SetString(PyExc_TypeError, "<descriptor>.__objclass__."
 406                        "__qualname__ is not a unicode object");
 407        Py_XDECREF(type_qualname);
 408        return NULL;
 409    }
 410
 411    res = PyUnicode_FromFormat("%S.%S", type_qualname, descr->d_name);
 412    Py_DECREF(type_qualname);
 413    return res;
 414}
 415
 416static PyObject *
 417descr_get_qualname(PyDescrObject *descr)
 418{
 419    if (descr->d_qualname == NULL)
 420        descr->d_qualname = calculate_qualname(descr);
 421    Py_XINCREF(descr->d_qualname);
 422    return descr->d_qualname;
 423}
 424
 425static PyObject *
 426descr_reduce(PyDescrObject *descr)
 427{
 428    PyObject *builtins;
 429    PyObject *getattr;
 430    _Py_IDENTIFIER(getattr);
 431
 432    builtins = PyEval_GetBuiltins();
 433    getattr = _PyDict_GetItemId(builtins, &PyId_getattr);
 434    return Py_BuildValue("O(OO)", getattr, PyDescr_TYPE(descr),
 435                         PyDescr_NAME(descr));
 436}
 437
 438static PyMethodDef descr_methods[] = {
 439    {"__reduce__", (PyCFunction)descr_reduce, METH_NOARGS, NULL},
 440    {NULL, NULL}
 441};
 442
 443static PyMemberDef descr_members[] = {
 444    {"__objclass__", T_OBJECT, offsetof(PyDescrObject, d_type), READONLY},
 445    {"__name__", T_OBJECT, offsetof(PyDescrObject, d_name), READONLY},
 446    {0}
 447};
 448
 449static PyGetSetDef method_getset[] = {
 450    {"__doc__", (getter)method_get_doc},
 451    {"__qualname__", (getter)descr_get_qualname},
 452    {"__text_signature__", (getter)method_get_text_signature},
 453    {0}
 454};
 455
 456static PyObject *
 457member_get_doc(PyMemberDescrObject *descr, void *closure)
 458{
 459    if (descr->d_member->doc == NULL) {
 460        Py_RETURN_NONE;
 461    }
 462    return PyUnicode_FromString(descr->d_member->doc);
 463}
 464
 465static PyGetSetDef member_getset[] = {
 466    {"__doc__", (getter)member_get_doc},
 467    {"__qualname__", (getter)descr_get_qualname},
 468    {0}
 469};
 470
 471static PyObject *
 472getset_get_doc(PyGetSetDescrObject *descr, void *closure)
 473{
 474    if (descr->d_getset->doc == NULL) {
 475        Py_RETURN_NONE;
 476    }
 477    return PyUnicode_FromString(descr->d_getset->doc);
 478}
 479
 480static PyGetSetDef getset_getset[] = {
 481    {"__doc__", (getter)getset_get_doc},
 482    {"__qualname__", (getter)descr_get_qualname},
 483    {0}
 484};
 485
 486static PyObject *
 487wrapperdescr_get_doc(PyWrapperDescrObject *descr, void *closure)
 488{
 489    return _PyType_GetDocFromInternalDoc(descr->d_base->name, descr->d_base->doc);
 490}
 491
 492static PyObject *
 493wrapperdescr_get_text_signature(PyWrapperDescrObject *descr, void *closure)
 494{
 495    return _PyType_GetTextSignatureFromInternalDoc(descr->d_base->name, descr->d_base->doc);
 496}
 497
 498static PyGetSetDef wrapperdescr_getset[] = {
 499    {"__doc__", (getter)wrapperdescr_get_doc},
 500    {"__qualname__", (getter)descr_get_qualname},
 501    {"__text_signature__", (getter)wrapperdescr_get_text_signature},
 502    {0}
 503};
 504
 505static int
 506descr_traverse(PyObject *self, visitproc visit, void *arg)
 507{
 508    PyDescrObject *descr = (PyDescrObject *)self;
 509    Py_VISIT(descr->d_type);
 510    return 0;
 511}
 512
 513PyTypeObject PyMethodDescr_Type = {
 514    PyVarObject_HEAD_INIT(&PyType_Type, 0)
 515    "method_descriptor",
 516    sizeof(PyMethodDescrObject),
 517    0,
 518    (destructor)descr_dealloc,                  /* tp_dealloc */
 519    0,                                          /* tp_print */
 520    0,                                          /* tp_getattr */
 521    0,                                          /* tp_setattr */
 522    0,                                          /* tp_reserved */
 523    (reprfunc)method_repr,                      /* tp_repr */
 524    0,                                          /* tp_as_number */
 525    0,                                          /* tp_as_sequence */
 526    0,                                          /* tp_as_mapping */
 527    0,                                          /* tp_hash */
 528    (ternaryfunc)methoddescr_call,              /* tp_call */
 529    0,                                          /* tp_str */
 530    PyObject_GenericGetAttr,                    /* tp_getattro */
 531    0,                                          /* tp_setattro */
 532    0,                                          /* tp_as_buffer */
 533    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
 534    0,                                          /* tp_doc */
 535    descr_traverse,                             /* tp_traverse */
 536    0,                                          /* tp_clear */
 537    0,                                          /* tp_richcompare */
 538    0,                                          /* tp_weaklistoffset */
 539    0,                                          /* tp_iter */
 540    0,                                          /* tp_iternext */
 541    descr_methods,                              /* tp_methods */
 542    descr_members,                              /* tp_members */
 543    method_getset,                              /* tp_getset */
 544    0,                                          /* tp_base */
 545    0,                                          /* tp_dict */
 546    (descrgetfunc)method_get,                   /* tp_descr_get */
 547    0,                                          /* tp_descr_set */
 548};
 549
 550/* This is for METH_CLASS in C, not for "f = classmethod(f)" in Python! */
 551PyTypeObject PyClassMethodDescr_Type = {
 552    PyVarObject_HEAD_INIT(&PyType_Type, 0)
 553    "classmethod_descriptor",
 554    sizeof(PyMethodDescrObject),
 555    0,
 556    (destructor)descr_dealloc,                  /* tp_dealloc */
 557    0,                                          /* tp_print */
 558    0,                                          /* tp_getattr */
 559    0,                                          /* tp_setattr */
 560    0,                                          /* tp_reserved */
 561    (reprfunc)method_repr,                      /* tp_repr */
 562    0,                                          /* tp_as_number */
 563    0,                                          /* tp_as_sequence */
 564    0,                                          /* tp_as_mapping */
 565    0,                                          /* tp_hash */
 566    (ternaryfunc)classmethoddescr_call,         /* tp_call */
 567    0,                                          /* tp_str */
 568    PyObject_GenericGetAttr,                    /* tp_getattro */
 569    0,                                          /* tp_setattro */
 570    0,                                          /* tp_as_buffer */
 571    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
 572    0,                                          /* tp_doc */
 573    descr_traverse,                             /* tp_traverse */
 574    0,                                          /* tp_clear */
 575    0,                                          /* tp_richcompare */
 576    0,                                          /* tp_weaklistoffset */
 577    0,                                          /* tp_iter */
 578    0,                                          /* tp_iternext */
 579    descr_methods,                              /* tp_methods */
 580    descr_members,                              /* tp_members */
 581    method_getset,                              /* tp_getset */
 582    0,                                          /* tp_base */
 583    0,                                          /* tp_dict */
 584    (descrgetfunc)classmethod_get,              /* tp_descr_get */
 585    0,                                          /* tp_descr_set */
 586};
 587
 588PyTypeObject PyMemberDescr_Type = {
 589    PyVarObject_HEAD_INIT(&PyType_Type, 0)
 590    "member_descriptor",
 591    sizeof(PyMemberDescrObject),
 592    0,
 593    (destructor)descr_dealloc,                  /* tp_dealloc */
 594    0,                                          /* tp_print */
 595    0,                                          /* tp_getattr */
 596    0,                                          /* tp_setattr */
 597    0,                                          /* tp_reserved */
 598    (reprfunc)member_repr,                      /* tp_repr */
 599    0,                                          /* tp_as_number */
 600    0,                                          /* tp_as_sequence */
 601    0,                                          /* tp_as_mapping */
 602    0,                                          /* tp_hash */
 603    0,                                          /* tp_call */
 604    0,                                          /* tp_str */
 605    PyObject_GenericGetAttr,                    /* tp_getattro */
 606    0,                                          /* tp_setattro */
 607    0,                                          /* tp_as_buffer */
 608    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
 609    0,                                          /* tp_doc */
 610    descr_traverse,                             /* tp_traverse */
 611    0,                                          /* tp_clear */
 612    0,                                          /* tp_richcompare */
 613    0,                                          /* tp_weaklistoffset */
 614    0,                                          /* tp_iter */
 615    0,                                          /* tp_iternext */
 616    descr_methods,                              /* tp_methods */
 617    descr_members,                              /* tp_members */
 618    member_getset,                              /* tp_getset */
 619    0,                                          /* tp_base */
 620    0,                                          /* tp_dict */
 621    (descrgetfunc)member_get,                   /* tp_descr_get */
 622    (descrsetfunc)member_set,                   /* tp_descr_set */
 623};
 624
 625PyTypeObject PyGetSetDescr_Type = {
 626    PyVarObject_HEAD_INIT(&PyType_Type, 0)
 627    "getset_descriptor",
 628    sizeof(PyGetSetDescrObject),
 629    0,
 630    (destructor)descr_dealloc,                  /* tp_dealloc */
 631    0,                                          /* tp_print */
 632    0,                                          /* tp_getattr */
 633    0,                                          /* tp_setattr */
 634    0,                                          /* tp_reserved */
 635    (reprfunc)getset_repr,                      /* tp_repr */
 636    0,                                          /* tp_as_number */
 637    0,                                          /* tp_as_sequence */
 638    0,                                          /* tp_as_mapping */
 639    0,                                          /* tp_hash */
 640    0,                                          /* tp_call */
 641    0,                                          /* tp_str */
 642    PyObject_GenericGetAttr,                    /* tp_getattro */
 643    0,                                          /* tp_setattro */
 644    0,                                          /* tp_as_buffer */
 645    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
 646    0,                                          /* tp_doc */
 647    descr_traverse,                             /* tp_traverse */
 648    0,                                          /* tp_clear */
 649    0,                                          /* tp_richcompare */
 650    0,                                          /* tp_weaklistoffset */
 651    0,                                          /* tp_iter */
 652    0,                                          /* tp_iternext */
 653    0,                                          /* tp_methods */
 654    descr_members,                              /* tp_members */
 655    getset_getset,                              /* tp_getset */
 656    0,                                          /* tp_base */
 657    0,                                          /* tp_dict */
 658    (descrgetfunc)getset_get,                   /* tp_descr_get */
 659    (descrsetfunc)getset_set,                   /* tp_descr_set */
 660};
 661
 662PyTypeObject PyWrapperDescr_Type = {
 663    PyVarObject_HEAD_INIT(&PyType_Type, 0)
 664    "wrapper_descriptor",
 665    sizeof(PyWrapperDescrObject),
 666    0,
 667    (destructor)descr_dealloc,                  /* tp_dealloc */
 668    0,                                          /* tp_print */
 669    0,                                          /* tp_getattr */
 670    0,                                          /* tp_setattr */
 671    0,                                          /* tp_reserved */
 672    (reprfunc)wrapperdescr_repr,                /* tp_repr */
 673    0,                                          /* tp_as_number */
 674    0,                                          /* tp_as_sequence */
 675    0,                                          /* tp_as_mapping */
 676    0,                                          /* tp_hash */
 677    (ternaryfunc)wrapperdescr_call,             /* tp_call */
 678    0,                                          /* tp_str */
 679    PyObject_GenericGetAttr,                    /* tp_getattro */
 680    0,                                          /* tp_setattro */
 681    0,                                          /* tp_as_buffer */
 682    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
 683    0,                                          /* tp_doc */
 684    descr_traverse,                             /* tp_traverse */
 685    0,                                          /* tp_clear */
 686    0,                                          /* tp_richcompare */
 687    0,                                          /* tp_weaklistoffset */
 688    0,                                          /* tp_iter */
 689    0,                                          /* tp_iternext */
 690    descr_methods,                              /* tp_methods */
 691    descr_members,                              /* tp_members */
 692    wrapperdescr_getset,                        /* tp_getset */
 693    0,                                          /* tp_base */
 694    0,                                          /* tp_dict */
 695    (descrgetfunc)wrapperdescr_get,             /* tp_descr_get */
 696    0,                                          /* tp_descr_set */
 697};
 698
 699static PyDescrObject *
 700descr_new(PyTypeObject *descrtype, PyTypeObject *type, const char *name)
 701{
 702    PyDescrObject *descr;
 703
 704    descr = (PyDescrObject *)PyType_GenericAlloc(descrtype, 0);
 705    if (descr != NULL) {
 706        Py_XINCREF(type);
 707        descr->d_type = type;
 708        descr->d_name = PyUnicode_InternFromString(name);
 709        if (descr->d_name == NULL) {
 710            Py_DECREF(descr);
 711            descr = NULL;
 712        }
 713        else {
 714            descr->d_qualname = NULL;
 715        }
 716    }
 717    return descr;
 718}
 719
 720PyObject *
 721PyDescr_NewMethod(PyTypeObject *type, PyMethodDef *method)
 722{
 723    PyMethodDescrObject *descr;
 724
 725    descr = (PyMethodDescrObject *)descr_new(&PyMethodDescr_Type,
 726                                             type, method->ml_name);
 727    if (descr != NULL)
 728        descr->d_method = method;
 729    return (PyObject *)descr;
 730}
 731
 732PyObject *
 733PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)
 734{
 735    PyMethodDescrObject *descr;
 736
 737    descr = (PyMethodDescrObject *)descr_new(&PyClassMethodDescr_Type,
 738                                             type, method->ml_name);
 739    if (descr != NULL)
 740        descr->d_method = method;
 741    return (PyObject *)descr;
 742}
 743
 744PyObject *
 745PyDescr_NewMember(PyTypeObject *type, PyMemberDef *member)
 746{
 747    PyMemberDescrObject *descr;
 748
 749    descr = (PyMemberDescrObject *)descr_new(&PyMemberDescr_Type,
 750                                             type, member->name);
 751    if (descr != NULL)
 752        descr->d_member = member;
 753    return (PyObject *)descr;
 754}
 755
 756PyObject *
 757PyDescr_NewGetSet(PyTypeObject *type, PyGetSetDef *getset)
 758{
 759    PyGetSetDescrObject *descr;
 760
 761    descr = (PyGetSetDescrObject *)descr_new(&PyGetSetDescr_Type,
 762                                             type, getset->name);
 763    if (descr != NULL)
 764        descr->d_getset = getset;
 765    return (PyObject *)descr;
 766}
 767
 768PyObject *
 769PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
 770{
 771    PyWrapperDescrObject *descr;
 772
 773    descr = (PyWrapperDescrObject *)descr_new(&PyWrapperDescr_Type,
 774                                             type, base->name);
 775    if (descr != NULL) {
 776        descr->d_base = base;
 777        descr->d_wrapped = wrapped;
 778    }
 779    return (PyObject *)descr;
 780}
 781
 782
 783/* --- mappingproxy: read-only proxy for mappings --- */
 784
 785/* This has no reason to be in this file except that adding new files is a
 786   bit of a pain */
 787
 788typedef struct {
 789    PyObject_HEAD
 790    PyObject *mapping;
 791} mappingproxyobject;
 792
 793static Py_ssize_t
 794mappingproxy_len(mappingproxyobject *pp)
 795{
 796    return PyObject_Size(pp->mapping);
 797}
 798
 799static PyObject *
 800mappingproxy_getitem(mappingproxyobject *pp, PyObject *key)
 801{
 802    return PyObject_GetItem(pp->mapping, key);
 803}
 804
 805static PyMappingMethods mappingproxy_as_mapping = {
 806    (lenfunc)mappingproxy_len,                  /* mp_length */
 807    (binaryfunc)mappingproxy_getitem,           /* mp_subscript */
 808    0,                                          /* mp_ass_subscript */
 809};
 810
 811static int
 812mappingproxy_contains(mappingproxyobject *pp, PyObject *key)
 813{
 814    if (PyDict_CheckExact(pp->mapping))
 815        return PyDict_Contains(pp->mapping, key);
 816    else
 817        return PySequence_Contains(pp->mapping, key);
 818}
 819
 820static PySequenceMethods mappingproxy_as_sequence = {
 821    0,                                          /* sq_length */
 822    0,                                          /* sq_concat */
 823    0,                                          /* sq_repeat */
 824    0,                                          /* sq_item */
 825    0,                                          /* sq_slice */
 826    0,                                          /* sq_ass_item */
 827    0,                                          /* sq_ass_slice */
 828    (objobjproc)mappingproxy_contains,                 /* sq_contains */
 829    0,                                          /* sq_inplace_concat */
 830    0,                                          /* sq_inplace_repeat */
 831};
 832
 833static PyObject *
 834mappingproxy_get(mappingproxyobject *pp, PyObject *args)
 835{
 836    PyObject *key, *def = Py_None;
 837    _Py_IDENTIFIER(get);
 838
 839    if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &def))
 840        return NULL;
 841    return _PyObject_CallMethodIdObjArgs(pp->mapping, &PyId_get,
 842                                         key, def, NULL);
 843}
 844
 845static PyObject *
 846mappingproxy_keys(mappingproxyobject *pp)
 847{
 848    _Py_IDENTIFIER(keys);
 849    return _PyObject_CallMethodId(pp->mapping, &PyId_keys, NULL);
 850}
 851
 852static PyObject *
 853mappingproxy_values(mappingproxyobject *pp)
 854{
 855    _Py_IDENTIFIER(values);
 856    return _PyObject_CallMethodId(pp->mapping, &PyId_values, NULL);
 857}
 858
 859static PyObject *
 860mappingproxy_items(mappingproxyobject *pp)
 861{
 862    _Py_IDENTIFIER(items);
 863    return _PyObject_CallMethodId(pp->mapping, &PyId_items, NULL);
 864}
 865
 866static PyObject *
 867mappingproxy_copy(mappingproxyobject *pp)
 868{
 869    _Py_IDENTIFIER(copy);
 870    return _PyObject_CallMethodId(pp->mapping, &PyId_copy, NULL);
 871}
 872
 873/* WARNING: mappingproxy methods must not give access
 874            to the underlying mapping */
 875
 876static PyMethodDef mappingproxy_methods[] = {
 877    {"get",       (PyCFunction)mappingproxy_get,        METH_VARARGS,
 878     PyDoc_STR("D.get(k[,d]) -> D[k] if k in D, else d."
 879               "  d defaults to None.")},
 880    {"keys",      (PyCFunction)mappingproxy_keys,       METH_NOARGS,
 881     PyDoc_STR("D.keys() -> list of D's keys")},
 882    {"values",    (PyCFunction)mappingproxy_values,     METH_NOARGS,
 883     PyDoc_STR("D.values() -> list of D's values")},
 884    {"items",     (PyCFunction)mappingproxy_items,      METH_NOARGS,
 885     PyDoc_STR("D.items() -> list of D's (key, value) pairs, as 2-tuples")},
 886    {"copy",      (PyCFunction)mappingproxy_copy,       METH_NOARGS,
 887     PyDoc_STR("D.copy() -> a shallow copy of D")},
 888    {0}
 889};
 890
 891static void
 892mappingproxy_dealloc(mappingproxyobject *pp)
 893{
 894    _PyObject_GC_UNTRACK(pp);
 895    Py_DECREF(pp->mapping);
 896    PyObject_GC_Del(pp);
 897}
 898
 899static PyObject *
 900mappingproxy_getiter(mappingproxyobject *pp)
 901{
 902    return PyObject_GetIter(pp->mapping);
 903}
 904
 905static PyObject *
 906mappingproxy_str(mappingproxyobject *pp)
 907{
 908    return PyObject_Str(pp->mapping);
 909}
 910
 911static PyObject *
 912mappingproxy_repr(mappingproxyobject *pp)
 913{
 914    return PyUnicode_FromFormat("mappingproxy(%R)", pp->mapping);
 915}
 916
 917static int
 918mappingproxy_traverse(PyObject *self, visitproc visit, void *arg)
 919{
 920    mappingproxyobject *pp = (mappingproxyobject *)self;
 921    Py_VISIT(pp->mapping);
 922    return 0;
 923}
 924
 925static PyObject *
 926mappingproxy_richcompare(mappingproxyobject *v, PyObject *w, int op)
 927{
 928    return PyObject_RichCompare(v->mapping, w, op);
 929}
 930
 931static int
 932mappingproxy_check_mapping(PyObject *mapping)
 933{
 934    if (!PyMapping_Check(mapping)
 935        || PyList_Check(mapping)
 936        || PyTuple_Check(mapping)) {
 937        PyErr_Format(PyExc_TypeError,
 938                    "mappingproxy() argument must be a mapping, not %s",
 939                    Py_TYPE(mapping)->tp_name);
 940        return -1;
 941    }
 942    return 0;
 943}
 944
 945static PyObject*
 946mappingproxy_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 947{
 948    static char *kwlist[] = {"mapping", NULL};
 949    PyObject *mapping;
 950    mappingproxyobject *mappingproxy;
 951
 952    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:mappingproxy",
 953                                     kwlist, &mapping))
 954        return NULL;
 955
 956    if (mappingproxy_check_mapping(mapping) == -1)
 957        return NULL;
 958
 959    mappingproxy = PyObject_GC_New(mappingproxyobject, &PyDictProxy_Type);
 960    if (mappingproxy == NULL)
 961        return NULL;
 962    Py_INCREF(mapping);
 963    mappingproxy->mapping = mapping;
 964    _PyObject_GC_TRACK(mappingproxy);
 965    return (PyObject *)mappingproxy;
 966}
 967
 968PyTypeObject PyDictProxy_Type = {
 969    PyVarObject_HEAD_INIT(&PyType_Type, 0)
 970    "mappingproxy",                             /* tp_name */
 971    sizeof(mappingproxyobject),                 /* tp_basicsize */
 972    0,                                          /* tp_itemsize */
 973    /* methods */
 974    (destructor)mappingproxy_dealloc,           /* tp_dealloc */
 975    0,                                          /* tp_print */
 976    0,                                          /* tp_getattr */
 977    0,                                          /* tp_setattr */
 978    0,                                          /* tp_reserved */
 979    (reprfunc)mappingproxy_repr,                /* tp_repr */
 980    0,                                          /* tp_as_number */
 981    &mappingproxy_as_sequence,                  /* tp_as_sequence */
 982    &mappingproxy_as_mapping,                   /* tp_as_mapping */
 983    0,                                          /* tp_hash */
 984    0,                                          /* tp_call */
 985    (reprfunc)mappingproxy_str,                 /* tp_str */
 986    PyObject_GenericGetAttr,                    /* tp_getattro */
 987    0,                                          /* tp_setattro */
 988    0,                                          /* tp_as_buffer */
 989    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
 990    0,                                          /* tp_doc */
 991    mappingproxy_traverse,                      /* tp_traverse */
 992    0,                                          /* tp_clear */
 993    (richcmpfunc)mappingproxy_richcompare,      /* tp_richcompare */
 994    0,                                          /* tp_weaklistoffset */
 995    (getiterfunc)mappingproxy_getiter,          /* tp_iter */
 996    0,                                          /* tp_iternext */
 997    mappingproxy_methods,                       /* tp_methods */
 998    0,                                          /* tp_members */
 999    0,                                          /* tp_getset */
1000    0,                                          /* tp_base */
1001    0,                                          /* tp_dict */
1002    0,                                          /* tp_descr_get */
1003    0,                                          /* tp_descr_set */
1004    0,                                          /* tp_dictoffset */
1005    0,                                          /* tp_init */
1006    0,                                          /* tp_alloc */
1007    mappingproxy_new,                           /* tp_new */
1008};
1009
1010PyObject *
1011PyDictProxy_New(PyObject *mapping)
1012{
1013    mappingproxyobject *pp;
1014
1015    if (mappingproxy_check_mapping(mapping) == -1)
1016        return NULL;
1017
1018    pp = PyObject_GC_New(mappingproxyobject, &PyDictProxy_Type);
1019    if (pp != NULL) {
1020        Py_INCREF(mapping);
1021        pp->mapping = mapping;
1022        _PyObject_GC_TRACK(pp);
1023    }
1024    return (PyObject *)pp;
1025}
1026
1027
1028/* --- Wrapper object for "slot" methods --- */
1029
1030/* This has no reason to be in this file except that adding new files is a
1031   bit of a pain */
1032
1033typedef struct {
1034    PyObject_HEAD
1035    PyWrapperDescrObject *descr;
1036    PyObject *self;
1037} wrapperobject;
1038
1039#define Wrapper_Check(v) (Py_TYPE(v) == &_PyMethodWrapper_Type)
1040
1041static void
1042wrapper_dealloc(wrapperobject *wp)
1043{
1044    PyObject_GC_UnTrack(wp);
1045    Py_TRASHCAN_SAFE_BEGIN(wp)
1046    Py_XDECREF(wp->descr);
1047    Py_XDECREF(wp->self);
1048    PyObject_GC_Del(wp);
1049    Py_TRASHCAN_SAFE_END(wp)
1050}
1051
1052#define TEST_COND(cond) ((cond) ? Py_True : Py_False)
1053
1054static PyObject *
1055wrapper_richcompare(PyObject *a, PyObject *b, int op)
1056{
1057    intptr_t result;
1058    PyObject *v;
1059    PyWrapperDescrObject *a_descr, *b_descr;
1060
1061    assert(a != NULL && b != NULL);
1062
1063    /* both arguments should be wrapperobjects */
1064    if (!Wrapper_Check(a) || !Wrapper_Check(b)) {
1065        v = Py_NotImplemented;
1066        Py_INCREF(v);
1067        return v;
1068    }
1069
1070    /* compare by descriptor address; if the descriptors are the same,
1071       compare by the objects they're bound to */
1072    a_descr = ((wrapperobject *)a)->descr;
1073    b_descr = ((wrapperobject *)b)->descr;
1074    if (a_descr == b_descr) {
1075        a = ((wrapperobject *)a)->self;
1076        b = ((wrapperobject *)b)->self;
1077        return PyObject_RichCompare(a, b, op);
1078    }
1079
1080    result = a_descr - b_descr;
1081    switch (op) {
1082    case Py_EQ:
1083        v = TEST_COND(result == 0);
1084        break;
1085    case Py_NE:
1086        v = TEST_COND(result != 0);
1087        break;
1088    case Py_LE:
1089        v = TEST_COND(result <= 0);
1090        break;
1091    case Py_GE:
1092        v = TEST_COND(result >= 0);
1093        break;
1094    case Py_LT:
1095        v = TEST_COND(result < 0);
1096        break;
1097    case Py_GT:
1098        v = TEST_COND(result > 0);
1099        break;
1100    default:
1101        PyErr_BadArgument();
1102        return NULL;
1103    }
1104    Py_INCREF(v);
1105    return v;
1106}
1107
1108static Py_hash_t
1109wrapper_hash(wrapperobject *wp)
1110{
1111    Py_hash_t x, y;
1112    x = _Py_HashPointer(wp->descr);
1113    if (x == -1)
1114        return -1;
1115    y = PyObject_Hash(wp->self);
1116    if (y == -1)
1117        return -1;
1118    x = x ^ y;
1119    if (x == -1)
1120        x = -2;
1121    return x;
1122}
1123
1124static PyObject *
1125wrapper_repr(wrapperobject *wp)
1126{
1127    return PyUnicode_FromFormat("<method-wrapper '%s' of %s object at %p>",
1128                               wp->descr->d_base->name,
1129                               wp->self->ob_type->tp_name,
1130                               wp->self);
1131}
1132
1133static PyObject *
1134wrapper_reduce(wrapperobject *wp)
1135{
1136    PyObject *builtins;
1137    PyObject *getattr;
1138    _Py_IDENTIFIER(getattr);
1139
1140    builtins = PyEval_GetBuiltins();
1141    getattr = _PyDict_GetItemId(builtins, &PyId_getattr);
1142    return Py_BuildValue("O(OO)", getattr, wp->self, PyDescr_NAME(wp->descr));
1143}
1144
1145static PyMethodDef wrapper_methods[] = {
1146    {"__reduce__", (PyCFunction)wrapper_reduce, METH_NOARGS, NULL},
1147    {NULL, NULL}
1148};
1149
1150static PyMemberDef wrapper_members[] = {
1151    {"__self__", T_OBJECT, offsetof(wrapperobject, self), READONLY},
1152    {0}
1153};
1154
1155static PyObject *
1156wrapper_objclass(wrapperobject *wp)
1157{
1158    PyObject *c = (PyObject *)PyDescr_TYPE(wp->descr);
1159
1160    Py_INCREF(c);
1161    return c;
1162}
1163
1164static PyObject *
1165wrapper_name(wrapperobject *wp)
1166{
1167    const char *s = wp->descr->d_base->name;
1168
1169    return PyUnicode_FromString(s);
1170}
1171
1172static PyObject *
1173wrapper_doc(wrapperobject *wp, void *closure)
1174{
1175    return _PyType_GetDocFromInternalDoc(wp->descr->d_base->name, wp->descr->d_base->doc);
1176}
1177
1178static PyObject *
1179wrapper_text_signature(wrapperobject *wp, void *closure)
1180{
1181    return _PyType_GetTextSignatureFromInternalDoc(wp->descr->d_base->name, wp->descr->d_base->doc);
1182}
1183
1184static PyObject *
1185wrapper_qualname(wrapperobject *wp)
1186{
1187    return descr_get_qualname((PyDescrObject *)wp->descr);
1188}
1189
1190static PyGetSetDef wrapper_getsets[] = {
1191    {"__objclass__", (getter)wrapper_objclass},
1192    {"__name__", (getter)wrapper_name},
1193    {"__qualname__", (getter)wrapper_qualname},
1194    {"__doc__", (getter)wrapper_doc},
1195    {"__text_signature__", (getter)wrapper_text_signature},
1196    {0}
1197};
1198
1199static PyObject *
1200wrapper_call(wrapperobject *wp, PyObject *args, PyObject *kwds)
1201{
1202    wrapperfunc wrapper = wp->descr->d_base->wrapper;
1203    PyObject *self = wp->self;
1204
1205    if (wp->descr->d_base->flags & PyWrapperFlag_KEYWORDS) {
1206        wrapperfunc_kwds wk = (wrapperfunc_kwds)wrapper;
1207        return (*wk)(self, args, wp->descr->d_wrapped, kwds);
1208    }
1209
1210    if (kwds != NULL && (!PyDict_Check(kwds) || PyDict_GET_SIZE(kwds) != 0)) {
1211        PyErr_Format(PyExc_TypeError,
1212                     "wrapper %s doesn't take keyword arguments",
1213                     wp->descr->d_base->name);
1214        return NULL;
1215    }
1216    return (*wrapper)(self, args, wp->descr->d_wrapped);
1217}
1218
1219static int
1220wrapper_traverse(PyObject *self, visitproc visit, void *arg)
1221{
1222    wrapperobject *wp = (wrapperobject *)self;
1223    Py_VISIT(wp->descr);
1224    Py_VISIT(wp->self);
1225    return 0;
1226}
1227
1228PyTypeObject _PyMethodWrapper_Type = {
1229    PyVarObject_HEAD_INIT(&PyType_Type, 0)
1230    "method-wrapper",                           /* tp_name */
1231    sizeof(wrapperobject),                      /* tp_basicsize */
1232    0,                                          /* tp_itemsize */
1233    /* methods */
1234    (destructor)wrapper_dealloc,                /* tp_dealloc */
1235    0,                                          /* tp_print */
1236    0,                                          /* tp_getattr */
1237    0,                                          /* tp_setattr */
1238    0,                                          /* tp_reserved */
1239    (reprfunc)wrapper_repr,                     /* tp_repr */
1240    0,                                          /* tp_as_number */
1241    0,                                          /* tp_as_sequence */
1242    0,                                          /* tp_as_mapping */
1243    (hashfunc)wrapper_hash,                     /* tp_hash */
1244    (ternaryfunc)wrapper_call,                  /* tp_call */
1245    0,                                          /* tp_str */
1246    PyObject_GenericGetAttr,                    /* tp_getattro */
1247    0,                                          /* tp_setattro */
1248    0,                                          /* tp_as_buffer */
1249    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
1250    0,                                          /* tp_doc */
1251    wrapper_traverse,                           /* tp_traverse */
1252    0,                                          /* tp_clear */
1253    wrapper_richcompare,                        /* tp_richcompare */
1254    0,                                          /* tp_weaklistoffset */
1255    0,                                          /* tp_iter */
1256    0,                                          /* tp_iternext */
1257    wrapper_methods,                            /* tp_methods */
1258    wrapper_members,                            /* tp_members */
1259    wrapper_getsets,                            /* tp_getset */
1260    0,                                          /* tp_base */
1261    0,                                          /* tp_dict */
1262    0,                                          /* tp_descr_get */
1263    0,                                          /* tp_descr_set */
1264};
1265
1266PyObject *
1267PyWrapper_New(PyObject *d, PyObject *self)
1268{
1269    wrapperobject *wp;
1270    PyWrapperDescrObject *descr;
1271
1272    assert(PyObject_TypeCheck(d, &PyWrapperDescr_Type));
1273    descr = (PyWrapperDescrObject *)d;
1274    assert(_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
1275                                    (PyObject *)PyDescr_TYPE(descr)));
1276
1277    wp = PyObject_GC_New(wrapperobject, &_PyMethodWrapper_Type);
1278    if (wp != NULL) {
1279        Py_INCREF(descr);
1280        wp->descr = descr;
1281        Py_INCREF(self);
1282        wp->self = self;
1283        _PyObject_GC_TRACK(wp);
1284    }
1285    return (PyObject *)wp;
1286}
1287
1288
1289/* A built-in 'property' type */
1290
1291/*
1292class property(object):
1293
1294    def __init__(self, fget=None, fset=None, fdel=None, doc=None):
1295        if doc is None and fget is not None and hasattr(fget, "__doc__"):
1296            doc = fget.__doc__
1297        self.__get = fget
1298        self.__set = fset
1299        self.__del = fdel
1300        self.__doc__ = doc
1301
1302    def __get__(self, inst, type=None):
1303        if inst is None:
1304            return self
1305        if self.__get is None:
1306            raise AttributeError, "unreadable attribute"
1307        return self.__get(inst)
1308
1309    def __set__(self, inst, value):
1310        if self.__set is None:
1311            raise AttributeError, "can't set attribute"
1312        return self.__set(inst, value)
1313
1314    def __delete__(self, inst):
1315        if self.__del is None:
1316            raise AttributeError, "can't delete attribute"
1317        return self.__del(inst)
1318
1319*/
1320
1321typedef struct {
1322    PyObject_HEAD
1323    PyObject *prop_get;
1324    PyObject *prop_set;
1325    PyObject *prop_del;
1326    PyObject *prop_doc;
1327    int getter_doc;
1328} propertyobject;
1329
1330static PyObject * property_copy(PyObject *, PyObject *, PyObject *,
1331                                  PyObject *);
1332
1333static PyMemberDef property_members[] = {
1334    {"fget", T_OBJECT, offsetof(propertyobject, prop_get), READONLY},
1335    {"fset", T_OBJECT, offsetof(propertyobject, prop_set), READONLY},
1336    {"fdel", T_OBJECT, offsetof(propertyobject, prop_del), READONLY},
1337    {"__doc__",  T_OBJECT, offsetof(propertyobject, prop_doc), 0},
1338    {0}
1339};
1340
1341
1342PyDoc_STRVAR(getter_doc,
1343             "Descriptor to change the getter on a property.");
1344
1345static PyObject *
1346property_getter(PyObject *self, PyObject *getter)
1347{
1348    return property_copy(self, getter, NULL, NULL);
1349}
1350
1351
1352PyDoc_STRVAR(setter_doc,
1353             "Descriptor to change the setter on a property.");
1354
1355static PyObject *
1356property_setter(PyObject *self, PyObject *setter)
1357{
1358    return property_copy(self, NULL, setter, NULL);
1359}
1360
1361
1362PyDoc_STRVAR(deleter_doc,
1363             "Descriptor to change the deleter on a property.");
1364
1365static PyObject *
1366property_deleter(PyObject *self, PyObject *deleter)
1367{
1368    return property_copy(self, NULL, NULL, deleter);
1369}
1370
1371
1372static PyMethodDef property_methods[] = {
1373    {"getter", property_getter, METH_O, getter_doc},
1374    {"setter", property_setter, METH_O, setter_doc},
1375    {"deleter", property_deleter, METH_O, deleter_doc},
1376    {0}
1377};
1378
1379
1380static void
1381property_dealloc(PyObject *self)
1382{
1383    propertyobject *gs = (propertyobject *)self;
1384
1385    _PyObject_GC_UNTRACK(self);
1386    Py_XDECREF(gs->prop_get);
1387    Py_XDECREF(gs->prop_set);
1388    Py_XDECREF(gs->prop_del);
1389    Py_XDECREF(gs->prop_doc);
1390    self->ob_type->tp_free(self);
1391}
1392
1393static PyObject *
1394property_descr_get(PyObject *self, PyObject *obj, PyObject *type)
1395{
1396    static PyObject * volatile cached_args = NULL;
1397    PyObject *args;
1398    PyObject *ret;
1399    propertyobject *gs = (propertyobject *)self;
1400
1401    if (obj == NULL || obj == Py_None) {
1402        Py_INCREF(self);
1403        return self;
1404    }
1405    if (gs->prop_get == NULL) {
1406        PyErr_SetString(PyExc_AttributeError, "unreadable attribute");
1407        return NULL;
1408    }
1409    args = cached_args;
1410    cached_args = NULL;
1411    if (!args) {
1412        args = PyTuple_New(1);
1413        if (!args)
1414            return NULL;
1415        _PyObject_GC_UNTRACK(args);
1416    }
1417    Py_INCREF(obj);
1418    PyTuple_SET_ITEM(args, 0, obj);
1419    ret = PyObject_Call(gs->prop_get, args, NULL);
1420    if (cached_args == NULL && Py_REFCNT(args) == 1) {
1421        assert(Py_SIZE(args) == 1);
1422        assert(PyTuple_GET_ITEM(args, 0) == obj);
1423        cached_args = args;
1424        Py_DECREF(obj);
1425    }
1426    else {
1427        assert(Py_REFCNT(args) >= 1);
1428        _PyObject_GC_TRACK(args);
1429        Py_DECREF(args);
1430    }
1431    return ret;
1432}
1433
1434static int
1435property_descr_set(PyObject *self, PyObject *obj, PyObject *value)
1436{
1437    propertyobject *gs = (propertyobject *)self;
1438    PyObject *func, *res;
1439
1440    if (value == NULL)
1441        func = gs->prop_del;
1442    else
1443        func = gs->prop_set;
1444    if (func == NULL) {
1445        PyErr_SetString(PyExc_AttributeError,
1446                        value == NULL ?
1447                        "can't delete attribute" :
1448                "can't set attribute");
1449        return -1;
1450    }
1451    if (value == NULL)
1452        res = PyObject_CallFunctionObjArgs(func, obj, NULL);
1453    else
1454        res = PyObject_CallFunctionObjArgs(func, obj, value, NULL);
1455    if (res == NULL)
1456        return -1;
1457    Py_DECREF(res);
1458    return 0;
1459}
1460
1461static PyObject *
1462property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del)
1463{
1464    propertyobject *pold = (propertyobject *)old;
1465    PyObject *new, *type, *doc;
1466
1467    type = PyObject_Type(old);
1468    if (type == NULL)
1469        return NULL;
1470
1471    if (get == NULL || get == Py_None) {
1472        Py_XDECREF(get);
1473        get = pold->prop_get ? pold->prop_get : Py_None;
1474    }
1475    if (set == NULL || set == Py_None) {
1476        Py_XDECREF(set);
1477        set = pold->prop_set ? pold->prop_set : Py_None;
1478    }
1479    if (del == NULL || del == Py_None) {
1480        Py_XDECREF(del);
1481        del = pold->prop_del ? pold->prop_del : Py_None;
1482    }
1483    if (pold->getter_doc && get != Py_None) {
1484        /* make _init use __doc__ from getter */
1485        doc = Py_None;
1486    }
1487    else {
1488        doc = pold->prop_doc ? pold->prop_doc : Py_None;
1489    }
1490
1491    new =  PyObj