blob: f509a161bb9564a6fad3a6b583da139bb75a74ab [file] [log] [blame]
// types.UnionType -- used to represent e.g. Union[int, str], int | str
#include "Python.h"
#include "pycore_object.h" // _PyObject_GC_TRACK/UNTRACK
#include "pycore_typevarobject.h" // _PyTypeAlias_Type
#include "pycore_unionobject.h"
#include "structmember.h"
static PyObject *make_union(PyObject *);
typedef struct {
PyObject_HEAD
PyObject *args;
PyObject *parameters;
} unionobject;
static void
unionobject_dealloc(PyObject *self)
{
unionobject *alias = (unionobject *)self;
_PyObject_GC_UNTRACK(self);
Py_XDECREF(alias->args);
Py_XDECREF(alias->parameters);
Py_TYPE(self)->tp_free(self);
}
static int
union_traverse(PyObject *self, visitproc visit, void *arg)
{
unionobject *alias = (unionobject *)self;
Py_VISIT(alias->args);
Py_VISIT(alias->parameters);
return 0;
}
static Py_hash_t
union_hash(PyObject *self)
{
unionobject *alias = (unionobject *)self;
PyObject *args = PyFrozenSet_New(alias->args);
if (args == NULL) {
return (Py_hash_t)-1;
}
Py_hash_t hash = PyObject_Hash(args);
Py_DECREF(args);
return hash;
}
static PyObject *
union_richcompare(PyObject *a, PyObject *b, int op)
{
if (!_PyUnion_Check(b) || (op != Py_EQ && op != Py_NE)) {
Py_RETURN_NOTIMPLEMENTED;
}
PyObject *a_set = PySet_New(((unionobject*)a)->args);
if (a_set == NULL) {
return NULL;
}
PyObject *b_set = PySet_New(((unionobject*)b)->args);
if (b_set == NULL) {
Py_DECREF(a_set);
return NULL;
}
PyObject *result = PyObject_RichCompare(a_set, b_set, op);
Py_DECREF(b_set);
Py_DECREF(a_set);
return result;
}
static int
is_same(PyObject *left, PyObject *right)
{
int is_ga = _PyGenericAlias_Check(left) && _PyGenericAlias_Check(right);
return is_ga ? PyObject_RichCompareBool(left, right, Py_EQ) : left == right;
}
static int
contains(PyObject **items, Py_ssize_t size, PyObject *obj)
{
for (int i = 0; i < size; i++) {
int is_duplicate = is_same(items[i], obj);
if (is_duplicate) { // -1 or 1
return is_duplicate;
}
}
return 0;
}
static PyObject *
merge(PyObject **items1, Py_ssize_t size1,
PyObject **items2, Py_ssize_t size2)
{
PyObject *tuple = NULL;
Py_ssize_t pos = 0;
for (int i = 0; i < size2; i++) {
PyObject *arg = items2[i];
int is_duplicate = contains(items1, size1, arg);
if (is_duplicate < 0) {
Py_XDECREF(tuple);
return NULL;
}
if (is_duplicate) {
continue;
}
if (tuple == NULL) {
tuple = PyTuple_New(size1 + size2 - i);
if (tuple == NULL) {
return NULL;
}
for (; pos < size1; pos++) {
PyObject *a = items1[pos];
PyTuple_SET_ITEM(tuple, pos, Py_NewRef(a));
}
}
PyTuple_SET_ITEM(tuple, pos, Py_NewRef(arg));
pos++;
}
if (tuple) {
(void) _PyTuple_Resize(&tuple, pos);
}
return tuple;
}
static PyObject **
get_types(PyObject **obj, Py_ssize_t *size)
{
if (*obj == Py_None) {
*obj = (PyObject *)&_PyNone_Type;
}
if (_PyUnion_Check(*obj)) {
PyObject *args = ((unionobject *) *obj)->args;
*size = PyTuple_GET_SIZE(args);
return &PyTuple_GET_ITEM(args, 0);
}
else {
*size = 1;
return obj;
}
}
static int
is_unionable(PyObject *obj)
{
if (obj == Py_None ||
PyType_Check(obj) ||
_PyGenericAlias_Check(obj) ||
_PyUnion_Check(obj) ||
Py_IS_TYPE(obj, &_PyTypeAlias_Type)) {
return 1;
}
return 0;
}
PyObject *
_Py_union_type_or(PyObject* self, PyObject* other)
{
if (!is_unionable(self) || !is_unionable(other)) {
Py_RETURN_NOTIMPLEMENTED;
}
Py_ssize_t size1, size2;
PyObject **items1 = get_types(&self, &size1);
PyObject **items2 = get_types(&other, &size2);
PyObject *tuple = merge(items1, size1, items2, size2);
if (tuple == NULL) {
if (PyErr_Occurred()) {
return NULL;
}
return Py_NewRef(self);
}
PyObject *new_union = make_union(tuple);
Py_DECREF(tuple);
return new_union;
}
static int
union_repr_item(_PyUnicodeWriter *writer, PyObject *p)
{
PyObject *qualname = NULL;
PyObject *module = NULL;
PyObject *tmp;
PyObject *r = NULL;
int err;
if (p == (PyObject *)&_PyNone_Type) {
return _PyUnicodeWriter_WriteASCIIString(writer, "None", 4);
}
if (_PyObject_LookupAttr(p, &_Py_ID(__origin__), &tmp) < 0) {
goto exit;
}
if (tmp) {
Py_DECREF(tmp);
if (_PyObject_LookupAttr(p, &_Py_ID(__args__), &tmp) < 0) {
goto exit;
}
if (tmp) {
// It looks like a GenericAlias
Py_DECREF(tmp);
goto use_repr;
}
}
if (_PyObject_LookupAttr(p, &_Py_ID(__qualname__), &qualname) < 0) {
goto exit;
}
if (qualname == NULL) {
goto use_repr;
}
if (_PyObject_LookupAttr(p, &_Py_ID(__module__), &module) < 0) {
goto exit;
}
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 exit;
}
else {
r = PyUnicode_FromFormat("%S.%S", module, qualname);
goto exit;
}
use_repr:
r = PyObject_Repr(p);
exit:
Py_XDECREF(qualname);
Py_XDECREF(module);
if (r == NULL) {
return -1;
}
err = _PyUnicodeWriter_WriteStr(writer, r);
Py_DECREF(r);
return err;
}
static PyObject *
union_repr(PyObject *self)
{
unionobject *alias = (unionobject *)self;
Py_ssize_t len = PyTuple_GET_SIZE(alias->args);
_PyUnicodeWriter writer;
_PyUnicodeWriter_Init(&writer);
for (Py_ssize_t i = 0; i < len; i++) {
if (i > 0 && _PyUnicodeWriter_WriteASCIIString(&writer, " | ", 3) < 0) {
goto error;
}
PyObject *p = PyTuple_GET_ITEM(alias->args, i);
if (union_repr_item(&writer, p) < 0) {
goto error;
}
}
return _PyUnicodeWriter_Finish(&writer);
error:
_PyUnicodeWriter_Dealloc(&writer);
return NULL;
}
static PyMemberDef union_members[] = {
{"__args__", T_OBJECT, offsetof(unionobject, args), READONLY},
{0}
};
static PyObject *
union_getitem(PyObject *self, PyObject *item)
{
unionobject *alias = (unionobject *)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_ssize_t nargs = PyTuple_GET_SIZE(newargs);
if (nargs == 0) {
res = make_union(newargs);
}
else {
res = Py_NewRef(PyTuple_GET_ITEM(newargs, 0));
for (Py_ssize_t iarg = 1; iarg < nargs; iarg++) {
PyObject *arg = PyTuple_GET_ITEM(newargs, iarg);
Py_SETREF(res, PyNumber_Or(res, arg));
if (res == NULL) {
break;
}
}
}
Py_DECREF(newargs);
return res;
}
static PyMappingMethods union_as_mapping = {
.mp_subscript = union_getitem,
};
static PyObject *
union_parameters(PyObject *self, void *Py_UNUSED(unused))
{
unionobject *alias = (unionobject *)self;
if (alias->parameters == NULL) {
alias->parameters = _Py_make_parameters(alias->args);
if (alias->parameters == NULL) {
return NULL;
}
}
return Py_NewRef(alias->parameters);
}
static PyGetSetDef union_properties[] = {
{"__parameters__", union_parameters, (setter)NULL, "Type variables in the types.UnionType.", NULL},
{0}
};
static PyNumberMethods union_as_number = {
.nb_or = _Py_union_type_or, // Add __or__ function
};
static const char* const cls_attrs[] = {
"__module__", // Required for compatibility with typing module
NULL,
};
static PyObject *
union_getattro(PyObject *self, PyObject *name)
{
unionobject *alias = (unionobject *)self;
if (PyUnicode_Check(name)) {
for (const char * const *p = cls_attrs; ; p++) {
if (*p == NULL) {
break;
}
if (_PyUnicode_EqualToASCIIString(name, *p)) {
return PyObject_GetAttr((PyObject *) Py_TYPE(alias), name);
}
}
}
return PyObject_GenericGetAttr(self, name);
}
PyObject *
_Py_union_args(PyObject *self)
{
assert(_PyUnion_Check(self));
return ((unionobject *) self)->args;
}
PyTypeObject _PyUnion_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "types.UnionType",
.tp_doc = PyDoc_STR("Represent a PEP 604 union type\n"
"\n"
"E.g. for int | str"),
.tp_basicsize = sizeof(unionobject),
.tp_dealloc = unionobject_dealloc,
.tp_alloc = PyType_GenericAlloc,
.tp_free = PyObject_GC_Del,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
.tp_traverse = union_traverse,
.tp_hash = union_hash,
.tp_getattro = union_getattro,
.tp_members = union_members,
.tp_richcompare = union_richcompare,
.tp_as_mapping = &union_as_mapping,
.tp_as_number = &union_as_number,
.tp_repr = union_repr,
.tp_getset = union_properties,
};
static PyObject *
make_union(PyObject *args)
{
assert(PyTuple_CheckExact(args));
unionobject *result = PyObject_GC_New(unionobject, &_PyUnion_Type);
if (result == NULL) {
return NULL;
}
result->parameters = NULL;
result->args = Py_NewRef(args);
_PyObject_GC_TRACK(result);
return (PyObject*)result;
}