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953 lines (879 loc) · 25.9 KB
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Copy pathgenericaliasobject.c
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953 lines (879 loc) · 25.9 KB
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// types.GenericAlias -- used to represent e.g. list[int].
#include "Python.h"
#include "pycore_object.h"
#include "pycore_unionobject.h" // _Py_union_type_or, _PyGenericAlias_Check
#include "structmember.h" // PyMemberDef
#include <stdbool.h>
typedef struct {
PyObject_HEAD
PyObject *origin;
PyObject *args;
PyObject *parameters;
PyObject *weakreflist;
// Whether we're a starred type, e.g. *tuple[int].
bool starred;
vectorcallfunc vectorcall;
} gaobject;
typedef struct {
PyObject_HEAD
PyObject *obj; /* Set to NULL when iterator is exhausted */
} gaiterobject;
static void
ga_dealloc(PyObject *self)
{
gaobject *alias = (gaobject *)self;
_PyObject_GC_UNTRACK(self);
if (alias->weakreflist != NULL) {
PyObject_ClearWeakRefs((PyObject *)alias);
}
Py_XDECREF(alias->origin);
Py_XDECREF(alias->args);
Py_XDECREF(alias->parameters);
Py_TYPE(self)->tp_free(self);
}
static int
ga_traverse(PyObject *self, visitproc visit, void *arg)
{
gaobject *alias = (gaobject *)self;
Py_VISIT(alias->origin);
Py_VISIT(alias->args);
Py_VISIT(alias->parameters);
return 0;
}
static int
ga_repr_item(_PyUnicodeWriter *writer, PyObject *p)
{
PyObject *qualname = NULL;
PyObject *module = NULL;
PyObject *r = NULL;
PyObject *tmp;
int err;
if (p == Py_Ellipsis) {
// The Ellipsis object
r = PyUnicode_FromString("...");
goto done;
}
if (_PyObject_LookupAttr(p, &_Py_ID(__origin__), &tmp) < 0) {
goto done;
}
if (tmp != NULL) {
Py_DECREF(tmp);
if (_PyObject_LookupAttr(p, &_Py_ID(__args__), &tmp) < 0) {
goto done;
}
if (tmp != NULL) {
Py_DECREF(tmp);
// It looks like a GenericAlias
goto use_repr;
}
}
if (_PyObject_LookupAttr(p, &_Py_ID(__qualname__), &qualname) < 0) {
goto done;
}
if (qualname == NULL) {
goto use_repr;
}
if (_PyObject_LookupAttr(p, &_Py_ID(__module__), &module) < 0) {
goto done;
}
if (module == NULL || module == Py_None) {
goto use_repr;
}
// Looks like a class
if (PyUnicode_Check(module) &&
_PyUnicode_EqualToASCIIString(module, "builtins"))
{
// builtins don't need a module name
r = PyObject_Str(qualname);
goto done;
}
else {
r = PyUnicode_FromFormat("%S.%S", module, qualname);
goto done;
}
use_repr:
r = PyObject_Repr(p);
done:
Py_XDECREF(qualname);
Py_XDECREF(module);
if (r == NULL) {
// error if any of the above PyObject_Repr/PyUnicode_From* fail
err = -1;
}
else {
err = _PyUnicodeWriter_WriteStr(writer, r);
Py_DECREF(r);
}
return err;
}
static PyObject *
ga_repr(PyObject *self)
{
gaobject *alias = (gaobject *)self;
Py_ssize_t len = PyTuple_GET_SIZE(alias->args);
_PyUnicodeWriter writer;
_PyUnicodeWriter_Init(&writer);
if (alias->starred) {
if (_PyUnicodeWriter_WriteASCIIString(&writer, "*", 1) < 0) {
goto error;
}
}
if (ga_repr_item(&writer, alias->origin) < 0) {
goto error;
}
if (_PyUnicodeWriter_WriteASCIIString(&writer, "[", 1) < 0) {
goto error;
}
for (Py_ssize_t i = 0; i < len; i++) {
if (i > 0) {
if (_PyUnicodeWriter_WriteASCIIString(&writer, ", ", 2) < 0) {
goto error;
}
}
PyObject *p = PyTuple_GET_ITEM(alias->args, i);
if (ga_repr_item(&writer, p) < 0) {
goto error;
}
}
if (len == 0) {
// for something like tuple[()] we should print a "()"
if (_PyUnicodeWriter_WriteASCIIString(&writer, "()", 2) < 0) {
goto error;
}
}
if (_PyUnicodeWriter_WriteASCIIString(&writer, "]", 1) < 0) {
goto error;
}
return _PyUnicodeWriter_Finish(&writer);
error:
_PyUnicodeWriter_Dealloc(&writer);
return NULL;
}
// Index of item in self[:len], or -1 if not found (self is a tuple)
static Py_ssize_t
tuple_index(PyObject *self, Py_ssize_t len, PyObject *item)
{
for (Py_ssize_t i = 0; i < len; i++) {
if (PyTuple_GET_ITEM(self, i) == item) {
return i;
}
}
return -1;
}
static int
tuple_add(PyObject *self, Py_ssize_t len, PyObject *item)
{
if (tuple_index(self, len, item) < 0) {
Py_INCREF(item);
PyTuple_SET_ITEM(self, len, item);
return 1;
}
return 0;
}
static Py_ssize_t
tuple_extend(PyObject **dst, Py_ssize_t dstindex,
PyObject **src, Py_ssize_t count)
{
assert(count >= 0);
if (_PyTuple_Resize(dst, PyTuple_GET_SIZE(*dst) + count - 1) != 0) {
return -1;
}
assert(dstindex + count <= PyTuple_GET_SIZE(*dst));
for (Py_ssize_t i = 0; i < count; ++i) {
PyObject *item = src[i];
Py_INCREF(item);
PyTuple_SET_ITEM(*dst, dstindex + i, item);
}
return dstindex + count;
}
PyObject *
_Py_make_parameters(PyObject *args)
{
Py_ssize_t nargs = PyTuple_GET_SIZE(args);
Py_ssize_t len = nargs;
PyObject *parameters = PyTuple_New(len);
if (parameters == NULL)
return NULL;
Py_ssize_t iparam = 0;
for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
PyObject *t = PyTuple_GET_ITEM(args, iarg);
PyObject *subst;
if (_PyObject_LookupAttr(t, &_Py_ID(__typing_subst__), &subst) < 0) {
Py_DECREF(parameters);
return NULL;
}
if (subst) {
iparam += tuple_add(parameters, iparam, t);
Py_DECREF(subst);
}
else {
PyObject *subparams;
if (_PyObject_LookupAttr(t, &_Py_ID(__parameters__),
&subparams) < 0) {
Py_DECREF(parameters);
return NULL;
}
if (subparams && PyTuple_Check(subparams)) {
Py_ssize_t len2 = PyTuple_GET_SIZE(subparams);
Py_ssize_t needed = len2 - 1 - (iarg - iparam);
if (needed > 0) {
len += needed;
if (_PyTuple_Resize(¶meters, len) < 0) {
Py_DECREF(subparams);
Py_DECREF(parameters);
return NULL;
}
}
for (Py_ssize_t j = 0; j < len2; j++) {
PyObject *t2 = PyTuple_GET_ITEM(subparams, j);
iparam += tuple_add(parameters, iparam, t2);
}
}
Py_XDECREF(subparams);
}
}
if (iparam < len) {
if (_PyTuple_Resize(¶meters, iparam) < 0) {
Py_XDECREF(parameters);
return NULL;
}
}
return parameters;
}
/* If obj is a generic alias, substitute type variables params
with substitutions argitems. For example, if obj is list[T],
params is (T, S), and argitems is (str, int), return list[str].
If obj doesn't have a __parameters__ attribute or that's not
a non-empty tuple, return a new reference to obj. */
static PyObject *
subs_tvars(PyObject *obj, PyObject *params,
PyObject **argitems, Py_ssize_t nargs)
{
PyObject *subparams;
if (_PyObject_LookupAttr(obj, &_Py_ID(__parameters__), &subparams) < 0) {
return NULL;
}
if (subparams && PyTuple_Check(subparams) && PyTuple_GET_SIZE(subparams)) {
Py_ssize_t nparams = PyTuple_GET_SIZE(params);
Py_ssize_t nsubargs = PyTuple_GET_SIZE(subparams);
PyObject *subargs = PyTuple_New(nsubargs);
if (subargs == NULL) {
Py_DECREF(subparams);
return NULL;
}
Py_ssize_t j = 0;
for (Py_ssize_t i = 0; i < nsubargs; ++i) {
PyObject *arg = PyTuple_GET_ITEM(subparams, i);
Py_ssize_t iparam = tuple_index(params, nparams, arg);
if (iparam >= 0) {
PyObject *param = PyTuple_GET_ITEM(params, iparam);
arg = argitems[iparam];
if (Py_TYPE(param)->tp_iter && PyTuple_Check(arg)) { // TypeVarTuple
j = tuple_extend(&subargs, j,
&PyTuple_GET_ITEM(arg, 0),
PyTuple_GET_SIZE(arg));
if (j < 0) {
return NULL;
}
continue;
}
}
Py_INCREF(arg);
PyTuple_SET_ITEM(subargs, j, arg);
j++;
}
assert(j == PyTuple_GET_SIZE(subargs));
obj = PyObject_GetItem(obj, subargs);
Py_DECREF(subargs);
}
else {
Py_INCREF(obj);
}
Py_XDECREF(subparams);
return obj;
}
static int
_is_unpacked_typevartuple(PyObject *arg)
{
PyObject *tmp;
if (PyType_Check(arg)) { // TODO: Add test
return 0;
}
int res = _PyObject_LookupAttr(arg, &_Py_ID(__typing_is_unpacked_typevartuple__), &tmp);
if (res > 0) {
res = PyObject_IsTrue(tmp);
Py_DECREF(tmp);
}
return res;
}
static PyObject *
_unpacked_tuple_args(PyObject *arg)
{
PyObject *result;
assert(!PyType_Check(arg));
// Fast path
if (_PyGenericAlias_Check(arg) &&
((gaobject *)arg)->starred &&
((gaobject *)arg)->origin == (PyObject *)&PyTuple_Type)
{
result = ((gaobject *)arg)->args;
Py_INCREF(result);
return result;
}
if (_PyObject_LookupAttr(arg, &_Py_ID(__typing_unpacked_tuple_args__), &result) > 0) {
if (result == Py_None) {
Py_DECREF(result);
return NULL;
}
return result;
}
return NULL;
}
static PyObject *
_unpack_args(PyObject *item)
{
PyObject *newargs = PyList_New(0);
if (newargs == NULL) {
return NULL;
}
int is_tuple = PyTuple_Check(item);
Py_ssize_t nitems = is_tuple ? PyTuple_GET_SIZE(item) : 1;
PyObject **argitems = is_tuple ? &PyTuple_GET_ITEM(item, 0) : &item;
for (Py_ssize_t i = 0; i < nitems; i++) {
item = argitems[i];
if (!PyType_Check(item)) {
PyObject *subargs = _unpacked_tuple_args(item);
if (subargs != NULL &&
PyTuple_Check(subargs) &&
!(PyTuple_GET_SIZE(subargs) &&
PyTuple_GET_ITEM(subargs, PyTuple_GET_SIZE(subargs)-1) == Py_Ellipsis))
{
if (PyList_SetSlice(newargs, PY_SSIZE_T_MAX, PY_SSIZE_T_MAX, subargs) < 0) {
Py_DECREF(subargs);
Py_DECREF(newargs);
return NULL;
}
Py_DECREF(subargs);
continue;
}
Py_XDECREF(subargs);
if (PyErr_Occurred()) {
Py_DECREF(newargs);
return NULL;
}
}
if (PyList_Append(newargs, item) < 0) {
Py_DECREF(newargs);
return NULL;
}
}
Py_SETREF(newargs, PySequence_Tuple(newargs));
return newargs;
}
PyObject *
_Py_subs_parameters(PyObject *self, PyObject *args, PyObject *parameters, PyObject *item)
{
Py_ssize_t nparams = PyTuple_GET_SIZE(parameters);
if (nparams == 0) {
return PyErr_Format(PyExc_TypeError,
"%R is not a generic class",
self);
}
item = _unpack_args(item);
for (Py_ssize_t i = 0; i < nparams; i++) {
PyObject *param = PyTuple_GET_ITEM(parameters, i);
PyObject *prepare, *tmp;
if (_PyObject_LookupAttr(param, &_Py_ID(__typing_prepare_subst__), &prepare) < 0) {
Py_DECREF(item);
return NULL;
}
if (prepare && prepare != Py_None) {
if (PyTuple_Check(item)) {
tmp = PyObject_CallFunction(prepare, "OO", self, item);
}
else {
tmp = PyObject_CallFunction(prepare, "O(O)", self, item);
}
Py_DECREF(prepare);
Py_SETREF(item, tmp);
if (item == NULL) {
return NULL;
}
}
}
int is_tuple = PyTuple_Check(item);
Py_ssize_t nitems = is_tuple ? PyTuple_GET_SIZE(item) : 1;
PyObject **argitems = is_tuple ? &PyTuple_GET_ITEM(item, 0) : &item;
if (nitems != nparams) {
Py_DECREF(item);
return PyErr_Format(PyExc_TypeError,
"Too %s arguments for %R; actual %zd, expected %zd",
nitems > nparams ? "many" : "few",
self, nitems, nparams);
}
/* Replace all type variables (specified by parameters)
with corresponding values specified by argitems.
t = list[T]; t[int] -> newargs = [int]
t = dict[str, T]; t[int] -> newargs = [str, int]
t = dict[T, list[S]]; t[str, int] -> newargs = [str, list[int]]
*/
Py_ssize_t nargs = PyTuple_GET_SIZE(args);
PyObject *newargs = PyTuple_New(nargs);
if (newargs == NULL) {
Py_DECREF(item);
return NULL;
}
for (Py_ssize_t iarg = 0, jarg = 0; iarg < nargs; iarg++) {
PyObject *arg = PyTuple_GET_ITEM(args, iarg);
int unpack = _is_unpacked_typevartuple(arg);
if (unpack < 0) {
Py_DECREF(newargs);
Py_DECREF(item);
return NULL;
}
PyObject *subst;
if (_PyObject_LookupAttr(arg, &_Py_ID(__typing_subst__), &subst) < 0) {
Py_DECREF(newargs);
Py_DECREF(item);
return NULL;
}
if (subst) {
Py_ssize_t iparam = tuple_index(parameters, nparams, arg);
assert(iparam >= 0);
arg = PyObject_CallOneArg(subst, argitems[iparam]);
Py_DECREF(subst);
}
else {
arg = subs_tvars(arg, parameters, argitems, nitems);
}
if (arg == NULL) {
Py_DECREF(newargs);
Py_DECREF(item);
return NULL;
}
if (unpack) {
jarg = tuple_extend(&newargs, jarg,
&PyTuple_GET_ITEM(arg, 0), PyTuple_GET_SIZE(arg));
Py_DECREF(arg);
if (jarg < 0) {
Py_DECREF(item);
return NULL;
}
}
else {
PyTuple_SET_ITEM(newargs, jarg, arg);
jarg++;
}
}
Py_DECREF(item);
return newargs;
}
PyDoc_STRVAR(genericalias__doc__,
"Represent a PEP 585 generic type\n"
"\n"
"E.g. for t = list[int], t.__origin__ is list and t.__args__ is (int,).");
static PyObject *
ga_getitem(PyObject *self, PyObject *item)
{
gaobject *alias = (gaobject *)self;
// Populate __parameters__ if needed.
if (alias->parameters == NULL) {
alias->parameters = _Py_make_parameters(alias->args);
if (alias->parameters == NULL) {
return NULL;
}
}
PyObject *newargs = _Py_subs_parameters(self, alias->args, alias->parameters, item);
if (newargs == NULL) {
return NULL;
}
PyObject *res = Py_GenericAlias(alias->origin, newargs);
((gaobject *)res)->starred = alias->starred;
Py_DECREF(newargs);
return res;
}
static PyMappingMethods ga_as_mapping = {
.mp_subscript = ga_getitem,
};
static Py_hash_t
ga_hash(PyObject *self)
{
gaobject *alias = (gaobject *)self;
// TODO: Hash in the hash for the origin
Py_hash_t h0 = PyObject_Hash(alias->origin);
if (h0 == -1) {
return -1;
}
Py_hash_t h1 = PyObject_Hash(alias->args);
if (h1 == -1) {
return -1;
}
return h0 ^ h1;
}
static inline PyObject *
set_orig_class(PyObject *obj, PyObject *self)
{
if (obj != NULL) {
if (PyObject_SetAttr(obj, &_Py_ID(__orig_class__), self) < 0) {
if (!PyErr_ExceptionMatches(PyExc_AttributeError) &&
!PyErr_ExceptionMatches(PyExc_TypeError))
{
Py_DECREF(obj);
return NULL;
}
PyErr_Clear();
}
}
return obj;
}
static PyObject *
ga_call(PyObject *self, PyObject *args, PyObject *kwds)
{
gaobject *alias = (gaobject *)self;
PyObject *obj = PyObject_Call(alias->origin, args, kwds);
return set_orig_class(obj, self);
}
static PyObject *
ga_vectorcall(PyObject *self, PyObject *const *args,
size_t nargsf, PyObject *kwnames)
{
gaobject *alias = (gaobject *) self;
PyObject *obj = PyVectorcall_Function(alias->origin)(alias->origin, args, nargsf, kwnames);
return set_orig_class(obj, self);
}
static const char* const attr_exceptions[] = {
"__origin__",
"__args__",
"__unpacked__",
"__parameters__",
"__typing_unpacked_tuple_args__",
"__mro_entries__",
"__reduce_ex__", // needed so we don't look up object.__reduce_ex__
"__reduce__",
"__copy__",
"__deepcopy__",
NULL,
};
static PyObject *
ga_getattro(PyObject *self, PyObject *name)
{
gaobject *alias = (gaobject *)self;
if (PyUnicode_Check(name)) {
for (const char * const *p = attr_exceptions; ; p++) {
if (*p == NULL) {
return PyObject_GetAttr(alias->origin, name);
}
if (_PyUnicode_EqualToASCIIString(name, *p)) {
break;
}
}
}
return PyObject_GenericGetAttr(self, name);
}
static PyObject *
ga_richcompare(PyObject *a, PyObject *b, int op)
{
if (!_PyGenericAlias_Check(b) ||
(op != Py_EQ && op != Py_NE))
{
Py_RETURN_NOTIMPLEMENTED;
}
if (op == Py_NE) {
PyObject *eq = ga_richcompare(a, b, Py_EQ);
if (eq == NULL)
return NULL;
Py_DECREF(eq);
if (eq == Py_True) {
Py_RETURN_FALSE;
}
else {
Py_RETURN_TRUE;
}
}
gaobject *aa = (gaobject *)a;
gaobject *bb = (gaobject *)b;
if (aa->starred != bb->starred) {
Py_RETURN_FALSE;
}
int eq = PyObject_RichCompareBool(aa->origin, bb->origin, Py_EQ);
if (eq < 0) {
return NULL;
}
if (!eq) {
Py_RETURN_FALSE;
}
return PyObject_RichCompare(aa->args, bb->args, Py_EQ);
}
static PyObject *
ga_mro_entries(PyObject *self, PyObject *args)
{
gaobject *alias = (gaobject *)self;
return PyTuple_Pack(1, alias->origin);
}
static PyObject *
ga_instancecheck(PyObject *self, PyObject *Py_UNUSED(ignored))
{
PyErr_SetString(PyExc_TypeError,
"isinstance() argument 2 cannot be a parameterized generic");
return NULL;
}
static PyObject *
ga_subclasscheck(PyObject *self, PyObject *Py_UNUSED(ignored))
{
PyErr_SetString(PyExc_TypeError,
"issubclass() argument 2 cannot be a parameterized generic");
return NULL;
}
static PyObject *
ga_reduce(PyObject *self, PyObject *Py_UNUSED(ignored))
{
gaobject *alias = (gaobject *)self;
if (alias->starred) {
PyObject *tmp = Py_GenericAlias(alias->origin, alias->args);
if (tmp != NULL) {
Py_SETREF(tmp, PyObject_GetIter(tmp));
}
if (tmp == NULL) {
return NULL;
}
return Py_BuildValue("N(N)", _PyEval_GetBuiltin(&_Py_ID(next)), tmp);
}
return Py_BuildValue("O(OO)", Py_TYPE(alias),
alias->origin, alias->args);
}
static PyObject *
ga_dir(PyObject *self, PyObject *Py_UNUSED(ignored))
{
gaobject *alias = (gaobject *)self;
PyObject *dir = PyObject_Dir(alias->origin);
if (dir == NULL) {
return NULL;
}
PyObject *dir_entry = NULL;
for (const char * const *p = attr_exceptions; ; p++) {
if (*p == NULL) {
break;
}
else {
dir_entry = PyUnicode_FromString(*p);
if (dir_entry == NULL) {
goto error;
}
int contains = PySequence_Contains(dir, dir_entry);
if (contains < 0) {
goto error;
}
if (contains == 0 && PyList_Append(dir, dir_entry) < 0) {
goto error;
}
Py_CLEAR(dir_entry);
}
}
return dir;
error:
Py_DECREF(dir);
Py_XDECREF(dir_entry);
return NULL;
}
static PyMethodDef ga_methods[] = {
{"__mro_entries__", ga_mro_entries, METH_O},
{"__instancecheck__", ga_instancecheck, METH_O},
{"__subclasscheck__", ga_subclasscheck, METH_O},
{"__reduce__", ga_reduce, METH_NOARGS},
{"__dir__", ga_dir, METH_NOARGS},
{0}
};
static PyMemberDef ga_members[] = {
{"__origin__", T_OBJECT, offsetof(gaobject, origin), READONLY},
{"__args__", T_OBJECT, offsetof(gaobject, args), READONLY},
{"__unpacked__", T_BOOL, offsetof(gaobject, starred), READONLY},
{0}
};
static PyObject *
ga_parameters(PyObject *self, void *unused)
{
gaobject *alias = (gaobject *)self;
if (alias->parameters == NULL) {
alias->parameters = _Py_make_parameters(alias->args);
if (alias->parameters == NULL) {
return NULL;
}
}
Py_INCREF(alias->parameters);
return alias->parameters;
}
static PyObject *
ga_unpacked_tuple_args(PyObject *self, void *unused)
{
gaobject *alias = (gaobject *)self;
if (alias->starred && alias->origin == (PyObject *)&PyTuple_Type) {
Py_INCREF(alias->args);
return alias->args;
}
Py_RETURN_NONE;
}
static PyGetSetDef ga_properties[] = {
{"__parameters__", ga_parameters, (setter)NULL, "Type variables in the GenericAlias.", NULL},
{"__typing_unpacked_tuple_args__", ga_unpacked_tuple_args, (setter)NULL, NULL},
{0}
};
/* A helper function to create GenericAlias' args tuple and set its attributes.
* Returns 1 on success, 0 on failure.
*/
static inline int
setup_ga(gaobject *alias, PyObject *origin, PyObject *args) {
if (!PyTuple_Check(args)) {
args = PyTuple_Pack(1, args);
if (args == NULL) {
return 0;
}
}
else {
Py_INCREF(args);
}
Py_INCREF(origin);
alias->origin = origin;
alias->args = args;
alias->parameters = NULL;
alias->weakreflist = NULL;
if (PyVectorcall_Function(origin) != NULL) {
alias->vectorcall = ga_vectorcall;
}
else {
alias->vectorcall = NULL;
}
return 1;
}
static PyObject *
ga_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
if (!_PyArg_NoKeywords("GenericAlias", kwds)) {
return NULL;
}
if (!_PyArg_CheckPositional("GenericAlias", PyTuple_GET_SIZE(args), 2, 2)) {
return NULL;
}
PyObject *origin = PyTuple_GET_ITEM(args, 0);
PyObject *arguments = PyTuple_GET_ITEM(args, 1);
gaobject *self = (gaobject *)type->tp_alloc(type, 0);
if (self == NULL) {
return NULL;
}
if (!setup_ga(self, origin, arguments)) {
Py_DECREF(self);
return NULL;
}
return (PyObject *)self;
}
static PyNumberMethods ga_as_number = {
.nb_or = _Py_union_type_or, // Add __or__ function
};
static PyObject *
ga_iternext(gaiterobject *gi) {
if (gi->obj == NULL) {
PyErr_SetNone(PyExc_StopIteration);
return NULL;
}
gaobject *alias = (gaobject *)gi->obj;
PyObject *starred_alias = Py_GenericAlias(alias->origin, alias->args);
if (starred_alias == NULL) {
return NULL;
}
((gaobject *)starred_alias)->starred = true;
Py_SETREF(gi->obj, NULL);
return starred_alias;
}
static void
ga_iter_dealloc(gaiterobject *gi) {
PyObject_GC_UnTrack(gi);
Py_XDECREF(gi->obj);
PyObject_GC_Del(gi);
}
static int
ga_iter_traverse(gaiterobject *gi, visitproc visit, void *arg)
{
Py_VISIT(gi->obj);
return 0;
}
static int
ga_iter_clear(PyObject *self) {
gaiterobject *gi = (gaiterobject *)self;
Py_CLEAR(gi->obj);
return 0;
}
static PyObject *
ga_iter_reduce(PyObject *self, PyObject *Py_UNUSED(ignored))
{
gaiterobject *gi = (gaiterobject *)self;
return Py_BuildValue("N(O)", _PyEval_GetBuiltin(&_Py_ID(iter)), gi->obj);
}
static PyMethodDef ga_iter_methods[] = {
{"__reduce__", ga_iter_reduce, METH_NOARGS},
{0}
};
// gh-91632: _Py_GenericAliasIterType is exported to be cleared
// in _PyTypes_FiniTypes.
PyTypeObject _Py_GenericAliasIterType = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "generic_alias_iterator",
.tp_basicsize = sizeof(gaiterobject),
.tp_iter = PyObject_SelfIter,
.tp_iternext = (iternextfunc)ga_iternext,
.tp_traverse = (traverseproc)ga_iter_traverse,
.tp_methods = ga_iter_methods,
.tp_dealloc = (destructor)ga_iter_dealloc,
.tp_clear = (inquiry)ga_iter_clear,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
};
static PyObject *
ga_iter(PyObject *self) {
gaiterobject *gi = PyObject_GC_New(gaiterobject, &_Py_GenericAliasIterType);
if (gi == NULL) {
return NULL;
}
gi->obj = Py_NewRef(self);
PyObject_GC_Track(gi);
return (PyObject *)gi;
}
// TODO:
// - argument clinic?
// - cache?
PyTypeObject Py_GenericAliasType = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "types.GenericAlias",
.tp_doc = genericalias__doc__,
.tp_basicsize = sizeof(gaobject),
.tp_dealloc = ga_dealloc,
.tp_repr = ga_repr,
.tp_as_number = &ga_as_number, // allow X | Y of GenericAlias objs
.tp_as_mapping = &ga_as_mapping,
.tp_hash = ga_hash,
.tp_call = ga_call,
.tp_getattro = ga_getattro,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_VECTORCALL,
.tp_traverse = ga_traverse,
.tp_richcompare = ga_richcompare,
.tp_weaklistoffset = offsetof(gaobject, weakreflist),
.tp_methods = ga_methods,
.tp_members = ga_members,
.tp_alloc = PyType_GenericAlloc,
.tp_new = ga_new,
.tp_free = PyObject_GC_Del,
.tp_getset = ga_properties,
.tp_iter = (getiterfunc)ga_iter,
.tp_vectorcall_offset = offsetof(gaobject, vectorcall),
};
PyObject *
Py_GenericAlias(PyObject *origin, PyObject *args)
{
gaobject *alias = (gaobject*) PyType_GenericAlloc(
(PyTypeObject *)&Py_GenericAliasType, 0);
if (alias == NULL) {
return NULL;
}
if (!setup_ga(alias, origin, args)) {
Py_DECREF(alias);
return NULL;
}
return (PyObject *)alias;
}