1 // types.UnionType -- used to represent e.g. Union[int, str], int | str
2 #include "Python.h"
3 #include "pycore_object.h" // _PyObject_GC_TRACK/UNTRACK
4 #include "pycore_typevarobject.h" // _PyTypeAlias_Type
5 #include "pycore_unionobject.h"
6 #include "structmember.h"
7
8
9 static PyObject *make_union(PyObject *);
10
11
12 typedef struct {
13 PyObject_HEAD
14 PyObject *args;
15 PyObject *parameters;
16 } unionobject;
17
18 static void
19 unionobject_dealloc(PyObject *self)
20 {
21 unionobject *alias = (unionobject *)self;
22
23 _PyObject_GC_UNTRACK(self);
24
25 Py_XDECREF(alias->args);
26 Py_XDECREF(alias->parameters);
27 Py_TYPE(self)->tp_free(self);
28 }
29
30 static int
31 union_traverse(PyObject *self, visitproc visit, void *arg)
32 {
33 unionobject *alias = (unionobject *)self;
34 Py_VISIT(alias->args);
35 Py_VISIT(alias->parameters);
36 return 0;
37 }
38
39 static Py_hash_t
40 union_hash(PyObject *self)
41 {
42 unionobject *alias = (unionobject *)self;
43 PyObject *args = PyFrozenSet_New(alias->args);
44 if (args == NULL) {
45 return (Py_hash_t)-1;
46 }
47 Py_hash_t hash = PyObject_Hash(args);
48 Py_DECREF(args);
49 return hash;
50 }
51
52 static PyObject *
53 union_richcompare(PyObject *a, PyObject *b, int op)
54 {
55 if (!_PyUnion_Check(b) || (op != Py_EQ && op != Py_NE)) {
56 Py_RETURN_NOTIMPLEMENTED;
57 }
58
59 PyObject *a_set = PySet_New(((unionobject*)a)->args);
60 if (a_set == NULL) {
61 return NULL;
62 }
63 PyObject *b_set = PySet_New(((unionobject*)b)->args);
64 if (b_set == NULL) {
65 Py_DECREF(a_set);
66 return NULL;
67 }
68 PyObject *result = PyObject_RichCompare(a_set, b_set, op);
69 Py_DECREF(b_set);
70 Py_DECREF(a_set);
71 return result;
72 }
73
74 static int
75 is_same(PyObject *left, PyObject *right)
76 {
77 int is_ga = _PyGenericAlias_Check(left) && _PyGenericAlias_Check(right);
78 return is_ga ? PyObject_RichCompareBool(left, right, Py_EQ) : left == right;
79 }
80
81 static int
82 contains(PyObject **items, Py_ssize_t size, PyObject *obj)
83 {
84 for (int i = 0; i < size; i++) {
85 int is_duplicate = is_same(items[i], obj);
86 if (is_duplicate) { // -1 or 1
87 return is_duplicate;
88 }
89 }
90 return 0;
91 }
92
93 static PyObject *
94 merge(PyObject **items1, Py_ssize_t size1,
95 PyObject **items2, Py_ssize_t size2)
96 {
97 PyObject *tuple = NULL;
98 Py_ssize_t pos = 0;
99
100 for (int i = 0; i < size2; i++) {
101 PyObject *arg = items2[i];
102 int is_duplicate = contains(items1, size1, arg);
103 if (is_duplicate < 0) {
104 Py_XDECREF(tuple);
105 return NULL;
106 }
107 if (is_duplicate) {
108 continue;
109 }
110
111 if (tuple == NULL) {
112 tuple = PyTuple_New(size1 + size2 - i);
113 if (tuple == NULL) {
114 return NULL;
115 }
116 for (; pos < size1; pos++) {
117 PyObject *a = items1[pos];
118 PyTuple_SET_ITEM(tuple, pos, Py_NewRef(a));
119 }
120 }
121 PyTuple_SET_ITEM(tuple, pos, Py_NewRef(arg));
122 pos++;
123 }
124
125 if (tuple) {
126 (void) _PyTuple_Resize(&tuple, pos);
127 }
128 return tuple;
129 }
130
131 static PyObject **
132 get_types(PyObject **obj, Py_ssize_t *size)
133 {
134 if (*obj == Py_None) {
135 *obj = (PyObject *)&_PyNone_Type;
136 }
137 if (_PyUnion_Check(*obj)) {
138 PyObject *args = ((unionobject *) *obj)->args;
139 *size = PyTuple_GET_SIZE(args);
140 return &PyTuple_GET_ITEM(args, 0);
141 }
142 else {
143 *size = 1;
144 return obj;
145 }
146 }
147
148 static int
149 is_unionable(PyObject *obj)
150 {
151 if (obj == Py_None ||
152 PyType_Check(obj) ||
153 _PyGenericAlias_Check(obj) ||
154 _PyUnion_Check(obj) ||
155 Py_IS_TYPE(obj, &_PyTypeAlias_Type)) {
156 return 1;
157 }
158 return 0;
159 }
160
161 PyObject *
162 _Py_union_type_or(PyObject* self, PyObject* other)
163 {
164 if (!is_unionable(self) || !is_unionable(other)) {
165 Py_RETURN_NOTIMPLEMENTED;
166 }
167
168 Py_ssize_t size1, size2;
169 PyObject **items1 = get_types(&self, &size1);
170 PyObject **items2 = get_types(&other, &size2);
171 PyObject *tuple = merge(items1, size1, items2, size2);
172 if (tuple == NULL) {
173 if (PyErr_Occurred()) {
174 return NULL;
175 }
176 return Py_NewRef(self);
177 }
178
179 PyObject *new_union = make_union(tuple);
180 Py_DECREF(tuple);
181 return new_union;
182 }
183
184 static int
185 union_repr_item(_PyUnicodeWriter *writer, PyObject *p)
186 {
187 PyObject *qualname = NULL;
188 PyObject *module = NULL;
189 PyObject *tmp;
190 PyObject *r = NULL;
191 int err;
192
193 if (p == (PyObject *)&_PyNone_Type) {
194 return _PyUnicodeWriter_WriteASCIIString(writer, "None", 4);
195 }
196
197 if (_PyObject_LookupAttr(p, &_Py_ID(__origin__), &tmp) < 0) {
198 goto exit;
199 }
200
201 if (tmp) {
202 Py_DECREF(tmp);
203 if (_PyObject_LookupAttr(p, &_Py_ID(__args__), &tmp) < 0) {
204 goto exit;
205 }
206 if (tmp) {
207 // It looks like a GenericAlias
208 Py_DECREF(tmp);
209 goto use_repr;
210 }
211 }
212
213 if (_PyObject_LookupAttr(p, &_Py_ID(__qualname__), &qualname) < 0) {
214 goto exit;
215 }
216 if (qualname == NULL) {
217 goto use_repr;
218 }
219 if (_PyObject_LookupAttr(p, &_Py_ID(__module__), &module) < 0) {
220 goto exit;
221 }
222 if (module == NULL || module == Py_None) {
223 goto use_repr;
224 }
225
226 // Looks like a class
227 if (PyUnicode_Check(module) &&
228 _PyUnicode_EqualToASCIIString(module, "builtins"))
229 {
230 // builtins don't need a module name
231 r = PyObject_Str(qualname);
232 goto exit;
233 }
234 else {
235 r = PyUnicode_FromFormat("%S.%S", module, qualname);
236 goto exit;
237 }
238
239 use_repr:
240 r = PyObject_Repr(p);
241 exit:
242 Py_XDECREF(qualname);
243 Py_XDECREF(module);
244 if (r == NULL) {
245 return -1;
246 }
247 err = _PyUnicodeWriter_WriteStr(writer, r);
248 Py_DECREF(r);
249 return err;
250 }
251
252 static PyObject *
253 union_repr(PyObject *self)
254 {
255 unionobject *alias = (unionobject *)self;
256 Py_ssize_t len = PyTuple_GET_SIZE(alias->args);
257
258 _PyUnicodeWriter writer;
259 _PyUnicodeWriter_Init(&writer);
260 for (Py_ssize_t i = 0; i < len; i++) {
261 if (i > 0 && _PyUnicodeWriter_WriteASCIIString(&writer, " | ", 3) < 0) {
262 goto error;
263 }
264 PyObject *p = PyTuple_GET_ITEM(alias->args, i);
265 if (union_repr_item(&writer, p) < 0) {
266 goto error;
267 }
268 }
269 return _PyUnicodeWriter_Finish(&writer);
270 error:
271 _PyUnicodeWriter_Dealloc(&writer);
272 return NULL;
273 }
274
275 static PyMemberDef union_members[] = {
276 {"__args__", T_OBJECT, offsetof(unionobject, args), READONLY},
277 {0}
278 };
279
280 static PyObject *
281 union_getitem(PyObject *self, PyObject *item)
282 {
283 unionobject *alias = (unionobject *)self;
284 // Populate __parameters__ if needed.
285 if (alias->parameters == NULL) {
286 alias->parameters = _Py_make_parameters(alias->args);
287 if (alias->parameters == NULL) {
288 return NULL;
289 }
290 }
291
292 PyObject *newargs = _Py_subs_parameters(self, alias->args, alias->parameters, item);
293 if (newargs == NULL) {
294 return NULL;
295 }
296
297 PyObject *res;
298 Py_ssize_t nargs = PyTuple_GET_SIZE(newargs);
299 if (nargs == 0) {
300 res = make_union(newargs);
301 }
302 else {
303 res = Py_NewRef(PyTuple_GET_ITEM(newargs, 0));
304 for (Py_ssize_t iarg = 1; iarg < nargs; iarg++) {
305 PyObject *arg = PyTuple_GET_ITEM(newargs, iarg);
306 Py_SETREF(res, PyNumber_Or(res, arg));
307 if (res == NULL) {
308 break;
309 }
310 }
311 }
312 Py_DECREF(newargs);
313 return res;
314 }
315
316 static PyMappingMethods union_as_mapping = {
317 .mp_subscript = union_getitem,
318 };
319
320 static PyObject *
321 union_parameters(PyObject *self, void *Py_UNUSED(unused))
322 {
323 unionobject *alias = (unionobject *)self;
324 if (alias->parameters == NULL) {
325 alias->parameters = _Py_make_parameters(alias->args);
326 if (alias->parameters == NULL) {
327 return NULL;
328 }
329 }
330 return Py_NewRef(alias->parameters);
331 }
332
333 static PyGetSetDef union_properties[] = {
334 {"__parameters__", union_parameters, (setter)NULL, "Type variables in the types.UnionType.", NULL},
335 {0}
336 };
337
338 static PyNumberMethods union_as_number = {
339 .nb_or = _Py_union_type_or, // Add __or__ function
340 };
341
342 static const char* const cls_attrs[] = {
343 "__module__", // Required for compatibility with typing module
344 NULL,
345 };
346
347 static PyObject *
348 union_getattro(PyObject *self, PyObject *name)
349 {
350 unionobject *alias = (unionobject *)self;
351 if (PyUnicode_Check(name)) {
352 for (const char * const *p = cls_attrs; ; p++) {
353 if (*p == NULL) {
354 break;
355 }
356 if (_PyUnicode_EqualToASCIIString(name, *p)) {
357 return PyObject_GetAttr((PyObject *) Py_TYPE(alias), name);
358 }
359 }
360 }
361 return PyObject_GenericGetAttr(self, name);
362 }
363
364 PyObject *
365 _Py_union_args(PyObject *self)
366 {
367 assert(_PyUnion_Check(self));
368 return ((unionobject *) self)->args;
369 }
370
371 PyTypeObject _PyUnion_Type = {
372 PyVarObject_HEAD_INIT(&PyType_Type, 0)
373 .tp_name = "types.UnionType",
374 .tp_doc = PyDoc_STR("Represent a PEP 604 union type\n"
375 "\n"
376 "E.g. for int | str"),
377 .tp_basicsize = sizeof(unionobject),
378 .tp_dealloc = unionobject_dealloc,
379 .tp_alloc = PyType_GenericAlloc,
380 .tp_free = PyObject_GC_Del,
381 .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
382 .tp_traverse = union_traverse,
383 .tp_hash = union_hash,
384 .tp_getattro = union_getattro,
385 .tp_members = union_members,
386 .tp_richcompare = union_richcompare,
387 .tp_as_mapping = &union_as_mapping,
388 .tp_as_number = &union_as_number,
389 .tp_repr = union_repr,
390 .tp_getset = union_properties,
391 };
392
393 static PyObject *
394 make_union(PyObject *args)
395 {
396 assert(PyTuple_CheckExact(args));
397
398 unionobject *result = PyObject_GC_New(unionobject, &_PyUnion_Type);
399 if (result == NULL) {
400 return NULL;
401 }
402
403 result->parameters = NULL;
404 result->args = Py_NewRef(args);
405 _PyObject_GC_TRACK(result);
406 return (PyObject*)result;
407 }