blob: 9edb6d23725d718bfb605f7da9928bf4854062e1 [file] [log] [blame]
// 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
typedef struct {
PyObject_HEAD
PyObject *origin;
PyObject *args;
PyObject *parameters;
PyObject* weakreflist;
} gaobject;
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)
{
_Py_IDENTIFIER(__module__);
_Py_IDENTIFIER(__qualname__);
_Py_IDENTIFIER(__origin__);
_Py_IDENTIFIER(__args__);
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_LookupAttrId(p, &PyId___origin__, &tmp) < 0) {
goto done;
}
if (tmp != NULL) {
Py_DECREF(tmp);
if (_PyObject_LookupAttrId(p, &PyId___args__, &tmp) < 0) {
goto done;
}
if (tmp != NULL) {
Py_DECREF(tmp);
// It looks like a GenericAlias
goto use_repr;
}
}
if (_PyObject_LookupAttrId(p, &PyId___qualname__, &qualname) < 0) {
goto done;
}
if (qualname == NULL) {
goto use_repr;
}
if (_PyObject_LookupAttrId(p, &PyId___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 (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;
}
// isinstance(obj, TypeVar) without importing typing.py.
// Returns -1 for errors.
static int
is_typevar(PyObject *obj)
{
PyTypeObject *type = Py_TYPE(obj);
if (strcmp(type->tp_name, "TypeVar") != 0) {
return 0;
}
PyObject *module = PyObject_GetAttrString((PyObject *)type, "__module__");
if (module == NULL) {
return -1;
}
int res = PyUnicode_Check(module)
&& _PyUnicode_EqualToASCIIString(module, "typing");
Py_DECREF(module);
return res;
}
// 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;
}
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);
if (PyType_Check(t)) {
continue;
}
int typevar = is_typevar(t);
if (typevar < 0) {
Py_DECREF(parameters);
return NULL;
}
if (typevar) {
iparam += tuple_add(parameters, iparam, t);
}
else {
_Py_IDENTIFIER(__parameters__);
PyObject *subparams;
if (_PyObject_LookupAttrId(t, &PyId___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(&parameters, 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(&parameters, 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)
{
if (PyType_Check(obj)) {
Py_INCREF(obj);
return obj;
}
_Py_IDENTIFIER(__parameters__);
PyObject *subparams;
if (_PyObject_LookupAttrId(obj, &PyId___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;
}
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) {
arg = argitems[iparam];
}
Py_INCREF(arg);
PyTuple_SET_ITEM(subargs, i, arg);
}
obj = PyObject_GetItem(obj, subargs);
Py_DECREF(subargs);
}
else {
Py_INCREF(obj);
}
Py_XDECREF(subparams);
return obj;
}
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,
"There are no type variables left in %R",
self);
}
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) {
return PyErr_Format(PyExc_TypeError,
"Too %s arguments for %R",
nitems > nparams ? "many" : "few",
self);
}
/* 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) {
return NULL;
}
for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
PyObject *arg = PyTuple_GET_ITEM(args, iarg);
int typevar = is_typevar(arg);
if (typevar < 0) {
Py_DECREF(newargs);
return NULL;
}
if (typevar) {
Py_ssize_t iparam = tuple_index(parameters, nparams, arg);
assert(iparam >= 0);
arg = argitems[iparam];
Py_INCREF(arg);
}
else {
arg = subs_tvars(arg, parameters, argitems);
if (arg == NULL) {
Py_DECREF(newargs);
return NULL;
}
}
PyTuple_SET_ITEM(newargs, iarg, arg);
}
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);
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 PyObject *
ga_call(PyObject *self, PyObject *args, PyObject *kwds)
{
gaobject *alias = (gaobject *)self;
PyObject *obj = PyObject_Call(alias->origin, args, kwds);
if (obj != NULL) {
if (PyObject_SetAttrString(obj, "__orig_class__", self) < 0) {
if (!PyErr_ExceptionMatches(PyExc_AttributeError) &&
!PyErr_ExceptionMatches(PyExc_TypeError))
{
Py_DECREF(obj);
return NULL;
}
PyErr_Clear();
}
}
return obj;
}
static const char* const attr_exceptions[] = {
"__origin__",
"__args__",
"__parameters__",
"__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;
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;
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},
{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 PyGetSetDef ga_properties[] = {
{"__parameters__", ga_parameters, (setter)NULL, "Type variables in the GenericAlias.", 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;
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
};
// 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,
.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,
};
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;
}