1 | #include "Python.h" |
2 | |
3 | #include "pycore_context.h" |
4 | #include "pycore_gc.h" // _PyObject_GC_MAY_BE_TRACKED() |
5 | #include "pycore_hamt.h" |
6 | #include "pycore_object.h" |
7 | #include "pycore_pyerrors.h" |
8 | #include "pycore_pystate.h" // _PyThreadState_GET() |
9 | #include "structmember.h" // PyMemberDef |
10 | |
11 | |
12 | #define CONTEXT_FREELIST_MAXLEN 255 |
13 | |
14 | |
15 | #include "clinic/context.c.h" |
16 | /*[clinic input] |
17 | module _contextvars |
18 | [clinic start generated code]*/ |
19 | /*[clinic end generated code: output=da39a3ee5e6b4b0d input=a0955718c8b8cea6]*/ |
20 | |
21 | |
22 | #define ENSURE_Context(o, err_ret) \ |
23 | if (!PyContext_CheckExact(o)) { \ |
24 | PyErr_SetString(PyExc_TypeError, \ |
25 | "an instance of Context was expected"); \ |
26 | return err_ret; \ |
27 | } |
28 | |
29 | #define ENSURE_ContextVar(o, err_ret) \ |
30 | if (!PyContextVar_CheckExact(o)) { \ |
31 | PyErr_SetString(PyExc_TypeError, \ |
32 | "an instance of ContextVar was expected"); \ |
33 | return err_ret; \ |
34 | } |
35 | |
36 | #define ENSURE_ContextToken(o, err_ret) \ |
37 | if (!PyContextToken_CheckExact(o)) { \ |
38 | PyErr_SetString(PyExc_TypeError, \ |
39 | "an instance of Token was expected"); \ |
40 | return err_ret; \ |
41 | } |
42 | |
43 | |
44 | /////////////////////////// Context API |
45 | |
46 | |
47 | static PyContext * |
48 | context_new_empty(void); |
49 | |
50 | static PyContext * |
51 | context_new_from_vars(PyHamtObject *vars); |
52 | |
53 | static inline PyContext * |
54 | context_get(void); |
55 | |
56 | static PyContextToken * |
57 | token_new(PyContext *ctx, PyContextVar *var, PyObject *val); |
58 | |
59 | static PyContextVar * |
60 | contextvar_new(PyObject *name, PyObject *def); |
61 | |
62 | static int |
63 | contextvar_set(PyContextVar *var, PyObject *val); |
64 | |
65 | static int |
66 | contextvar_del(PyContextVar *var); |
67 | |
68 | |
69 | static struct _Py_context_state * |
70 | get_context_state(void) |
71 | { |
72 | PyInterpreterState *interp = _PyInterpreterState_GET(); |
73 | return &interp->context; |
74 | } |
75 | |
76 | |
77 | PyObject * |
78 | _PyContext_NewHamtForTests(void) |
79 | { |
80 | return (PyObject *)_PyHamt_New(); |
81 | } |
82 | |
83 | |
84 | PyObject * |
85 | PyContext_New(void) |
86 | { |
87 | return (PyObject *)context_new_empty(); |
88 | } |
89 | |
90 | |
91 | PyObject * |
92 | PyContext_Copy(PyObject * octx) |
93 | { |
94 | ENSURE_Context(octx, NULL) |
95 | PyContext *ctx = (PyContext *)octx; |
96 | return (PyObject *)context_new_from_vars(ctx->ctx_vars); |
97 | } |
98 | |
99 | |
100 | PyObject * |
101 | PyContext_CopyCurrent(void) |
102 | { |
103 | PyContext *ctx = context_get(); |
104 | if (ctx == NULL) { |
105 | return NULL; |
106 | } |
107 | |
108 | return (PyObject *)context_new_from_vars(ctx->ctx_vars); |
109 | } |
110 | |
111 | |
112 | static int |
113 | _PyContext_Enter(PyThreadState *ts, PyObject *octx) |
114 | { |
115 | ENSURE_Context(octx, -1) |
116 | PyContext *ctx = (PyContext *)octx; |
117 | |
118 | if (ctx->ctx_entered) { |
119 | _PyErr_Format(ts, PyExc_RuntimeError, |
120 | "cannot enter context: %R is already entered" , ctx); |
121 | return -1; |
122 | } |
123 | |
124 | ctx->ctx_prev = (PyContext *)ts->context; /* borrow */ |
125 | ctx->ctx_entered = 1; |
126 | |
127 | Py_INCREF(ctx); |
128 | ts->context = (PyObject *)ctx; |
129 | ts->context_ver++; |
130 | |
131 | return 0; |
132 | } |
133 | |
134 | |
135 | int |
136 | PyContext_Enter(PyObject *octx) |
137 | { |
138 | PyThreadState *ts = _PyThreadState_GET(); |
139 | assert(ts != NULL); |
140 | return _PyContext_Enter(ts, octx); |
141 | } |
142 | |
143 | |
144 | static int |
145 | _PyContext_Exit(PyThreadState *ts, PyObject *octx) |
146 | { |
147 | ENSURE_Context(octx, -1) |
148 | PyContext *ctx = (PyContext *)octx; |
149 | |
150 | if (!ctx->ctx_entered) { |
151 | PyErr_Format(PyExc_RuntimeError, |
152 | "cannot exit context: %R has not been entered" , ctx); |
153 | return -1; |
154 | } |
155 | |
156 | if (ts->context != (PyObject *)ctx) { |
157 | /* Can only happen if someone misuses the C API */ |
158 | PyErr_SetString(PyExc_RuntimeError, |
159 | "cannot exit context: thread state references " |
160 | "a different context object" ); |
161 | return -1; |
162 | } |
163 | |
164 | Py_SETREF(ts->context, (PyObject *)ctx->ctx_prev); |
165 | ts->context_ver++; |
166 | |
167 | ctx->ctx_prev = NULL; |
168 | ctx->ctx_entered = 0; |
169 | |
170 | return 0; |
171 | } |
172 | |
173 | int |
174 | PyContext_Exit(PyObject *octx) |
175 | { |
176 | PyThreadState *ts = _PyThreadState_GET(); |
177 | assert(ts != NULL); |
178 | return _PyContext_Exit(ts, octx); |
179 | } |
180 | |
181 | |
182 | PyObject * |
183 | PyContextVar_New(const char *name, PyObject *def) |
184 | { |
185 | PyObject *pyname = PyUnicode_FromString(name); |
186 | if (pyname == NULL) { |
187 | return NULL; |
188 | } |
189 | PyContextVar *var = contextvar_new(pyname, def); |
190 | Py_DECREF(pyname); |
191 | return (PyObject *)var; |
192 | } |
193 | |
194 | |
195 | int |
196 | PyContextVar_Get(PyObject *ovar, PyObject *def, PyObject **val) |
197 | { |
198 | ENSURE_ContextVar(ovar, -1) |
199 | PyContextVar *var = (PyContextVar *)ovar; |
200 | |
201 | PyThreadState *ts = _PyThreadState_GET(); |
202 | assert(ts != NULL); |
203 | if (ts->context == NULL) { |
204 | goto not_found; |
205 | } |
206 | |
207 | if (var->var_cached != NULL && |
208 | var->var_cached_tsid == ts->id && |
209 | var->var_cached_tsver == ts->context_ver) |
210 | { |
211 | *val = var->var_cached; |
212 | goto found; |
213 | } |
214 | |
215 | assert(PyContext_CheckExact(ts->context)); |
216 | PyHamtObject *vars = ((PyContext *)ts->context)->ctx_vars; |
217 | |
218 | PyObject *found = NULL; |
219 | int res = _PyHamt_Find(vars, (PyObject*)var, &found); |
220 | if (res < 0) { |
221 | goto error; |
222 | } |
223 | if (res == 1) { |
224 | assert(found != NULL); |
225 | var->var_cached = found; /* borrow */ |
226 | var->var_cached_tsid = ts->id; |
227 | var->var_cached_tsver = ts->context_ver; |
228 | |
229 | *val = found; |
230 | goto found; |
231 | } |
232 | |
233 | not_found: |
234 | if (def == NULL) { |
235 | if (var->var_default != NULL) { |
236 | *val = var->var_default; |
237 | goto found; |
238 | } |
239 | |
240 | *val = NULL; |
241 | goto found; |
242 | } |
243 | else { |
244 | *val = def; |
245 | goto found; |
246 | } |
247 | |
248 | found: |
249 | Py_XINCREF(*val); |
250 | return 0; |
251 | |
252 | error: |
253 | *val = NULL; |
254 | return -1; |
255 | } |
256 | |
257 | |
258 | PyObject * |
259 | PyContextVar_Set(PyObject *ovar, PyObject *val) |
260 | { |
261 | ENSURE_ContextVar(ovar, NULL) |
262 | PyContextVar *var = (PyContextVar *)ovar; |
263 | |
264 | if (!PyContextVar_CheckExact(var)) { |
265 | PyErr_SetString( |
266 | PyExc_TypeError, "an instance of ContextVar was expected" ); |
267 | return NULL; |
268 | } |
269 | |
270 | PyContext *ctx = context_get(); |
271 | if (ctx == NULL) { |
272 | return NULL; |
273 | } |
274 | |
275 | PyObject *old_val = NULL; |
276 | int found = _PyHamt_Find(ctx->ctx_vars, (PyObject *)var, &old_val); |
277 | if (found < 0) { |
278 | return NULL; |
279 | } |
280 | |
281 | Py_XINCREF(old_val); |
282 | PyContextToken *tok = token_new(ctx, var, old_val); |
283 | Py_XDECREF(old_val); |
284 | |
285 | if (contextvar_set(var, val)) { |
286 | Py_DECREF(tok); |
287 | return NULL; |
288 | } |
289 | |
290 | return (PyObject *)tok; |
291 | } |
292 | |
293 | |
294 | int |
295 | PyContextVar_Reset(PyObject *ovar, PyObject *otok) |
296 | { |
297 | ENSURE_ContextVar(ovar, -1) |
298 | ENSURE_ContextToken(otok, -1) |
299 | PyContextVar *var = (PyContextVar *)ovar; |
300 | PyContextToken *tok = (PyContextToken *)otok; |
301 | |
302 | if (tok->tok_used) { |
303 | PyErr_Format(PyExc_RuntimeError, |
304 | "%R has already been used once" , tok); |
305 | return -1; |
306 | } |
307 | |
308 | if (var != tok->tok_var) { |
309 | PyErr_Format(PyExc_ValueError, |
310 | "%R was created by a different ContextVar" , tok); |
311 | return -1; |
312 | } |
313 | |
314 | PyContext *ctx = context_get(); |
315 | if (ctx != tok->tok_ctx) { |
316 | PyErr_Format(PyExc_ValueError, |
317 | "%R was created in a different Context" , tok); |
318 | return -1; |
319 | } |
320 | |
321 | tok->tok_used = 1; |
322 | |
323 | if (tok->tok_oldval == NULL) { |
324 | return contextvar_del(var); |
325 | } |
326 | else { |
327 | return contextvar_set(var, tok->tok_oldval); |
328 | } |
329 | } |
330 | |
331 | |
332 | /////////////////////////// PyContext |
333 | |
334 | /*[clinic input] |
335 | class _contextvars.Context "PyContext *" "&PyContext_Type" |
336 | [clinic start generated code]*/ |
337 | /*[clinic end generated code: output=da39a3ee5e6b4b0d input=bdf87f8e0cb580e8]*/ |
338 | |
339 | |
340 | static inline PyContext * |
341 | _context_alloc(void) |
342 | { |
343 | struct _Py_context_state *state = get_context_state(); |
344 | PyContext *ctx; |
345 | #ifdef Py_DEBUG |
346 | // _context_alloc() must not be called after _PyContext_Fini() |
347 | assert(state->numfree != -1); |
348 | #endif |
349 | if (state->numfree) { |
350 | state->numfree--; |
351 | ctx = state->freelist; |
352 | state->freelist = (PyContext *)ctx->ctx_weakreflist; |
353 | ctx->ctx_weakreflist = NULL; |
354 | _Py_NewReference((PyObject *)ctx); |
355 | } |
356 | else { |
357 | ctx = PyObject_GC_New(PyContext, &PyContext_Type); |
358 | if (ctx == NULL) { |
359 | return NULL; |
360 | } |
361 | } |
362 | |
363 | ctx->ctx_vars = NULL; |
364 | ctx->ctx_prev = NULL; |
365 | ctx->ctx_entered = 0; |
366 | ctx->ctx_weakreflist = NULL; |
367 | |
368 | return ctx; |
369 | } |
370 | |
371 | |
372 | static PyContext * |
373 | context_new_empty(void) |
374 | { |
375 | PyContext *ctx = _context_alloc(); |
376 | if (ctx == NULL) { |
377 | return NULL; |
378 | } |
379 | |
380 | ctx->ctx_vars = _PyHamt_New(); |
381 | if (ctx->ctx_vars == NULL) { |
382 | Py_DECREF(ctx); |
383 | return NULL; |
384 | } |
385 | |
386 | _PyObject_GC_TRACK(ctx); |
387 | return ctx; |
388 | } |
389 | |
390 | |
391 | static PyContext * |
392 | context_new_from_vars(PyHamtObject *vars) |
393 | { |
394 | PyContext *ctx = _context_alloc(); |
395 | if (ctx == NULL) { |
396 | return NULL; |
397 | } |
398 | |
399 | Py_INCREF(vars); |
400 | ctx->ctx_vars = vars; |
401 | |
402 | _PyObject_GC_TRACK(ctx); |
403 | return ctx; |
404 | } |
405 | |
406 | |
407 | static inline PyContext * |
408 | context_get(void) |
409 | { |
410 | PyThreadState *ts = _PyThreadState_GET(); |
411 | assert(ts != NULL); |
412 | PyContext *current_ctx = (PyContext *)ts->context; |
413 | if (current_ctx == NULL) { |
414 | current_ctx = context_new_empty(); |
415 | if (current_ctx == NULL) { |
416 | return NULL; |
417 | } |
418 | ts->context = (PyObject *)current_ctx; |
419 | } |
420 | return current_ctx; |
421 | } |
422 | |
423 | static int |
424 | context_check_key_type(PyObject *key) |
425 | { |
426 | if (!PyContextVar_CheckExact(key)) { |
427 | // abort(); |
428 | PyErr_Format(PyExc_TypeError, |
429 | "a ContextVar key was expected, got %R" , key); |
430 | return -1; |
431 | } |
432 | return 0; |
433 | } |
434 | |
435 | static PyObject * |
436 | context_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds) |
437 | { |
438 | if (PyTuple_Size(args) || (kwds != NULL && PyDict_Size(kwds))) { |
439 | PyErr_SetString( |
440 | PyExc_TypeError, "Context() does not accept any arguments" ); |
441 | return NULL; |
442 | } |
443 | return PyContext_New(); |
444 | } |
445 | |
446 | static int |
447 | context_tp_clear(PyContext *self) |
448 | { |
449 | Py_CLEAR(self->ctx_prev); |
450 | Py_CLEAR(self->ctx_vars); |
451 | return 0; |
452 | } |
453 | |
454 | static int |
455 | context_tp_traverse(PyContext *self, visitproc visit, void *arg) |
456 | { |
457 | Py_VISIT(self->ctx_prev); |
458 | Py_VISIT(self->ctx_vars); |
459 | return 0; |
460 | } |
461 | |
462 | static void |
463 | context_tp_dealloc(PyContext *self) |
464 | { |
465 | _PyObject_GC_UNTRACK(self); |
466 | |
467 | if (self->ctx_weakreflist != NULL) { |
468 | PyObject_ClearWeakRefs((PyObject*)self); |
469 | } |
470 | (void)context_tp_clear(self); |
471 | |
472 | struct _Py_context_state *state = get_context_state(); |
473 | #ifdef Py_DEBUG |
474 | // _context_alloc() must not be called after _PyContext_Fini() |
475 | assert(state->numfree != -1); |
476 | #endif |
477 | if (state->numfree < CONTEXT_FREELIST_MAXLEN) { |
478 | state->numfree++; |
479 | self->ctx_weakreflist = (PyObject *)state->freelist; |
480 | state->freelist = self; |
481 | } |
482 | else { |
483 | Py_TYPE(self)->tp_free(self); |
484 | } |
485 | } |
486 | |
487 | static PyObject * |
488 | context_tp_iter(PyContext *self) |
489 | { |
490 | return _PyHamt_NewIterKeys(self->ctx_vars); |
491 | } |
492 | |
493 | static PyObject * |
494 | context_tp_richcompare(PyObject *v, PyObject *w, int op) |
495 | { |
496 | if (!PyContext_CheckExact(v) || !PyContext_CheckExact(w) || |
497 | (op != Py_EQ && op != Py_NE)) |
498 | { |
499 | Py_RETURN_NOTIMPLEMENTED; |
500 | } |
501 | |
502 | int res = _PyHamt_Eq( |
503 | ((PyContext *)v)->ctx_vars, ((PyContext *)w)->ctx_vars); |
504 | if (res < 0) { |
505 | return NULL; |
506 | } |
507 | |
508 | if (op == Py_NE) { |
509 | res = !res; |
510 | } |
511 | |
512 | if (res) { |
513 | Py_RETURN_TRUE; |
514 | } |
515 | else { |
516 | Py_RETURN_FALSE; |
517 | } |
518 | } |
519 | |
520 | static Py_ssize_t |
521 | context_tp_len(PyContext *self) |
522 | { |
523 | return _PyHamt_Len(self->ctx_vars); |
524 | } |
525 | |
526 | static PyObject * |
527 | context_tp_subscript(PyContext *self, PyObject *key) |
528 | { |
529 | if (context_check_key_type(key)) { |
530 | return NULL; |
531 | } |
532 | PyObject *val = NULL; |
533 | int found = _PyHamt_Find(self->ctx_vars, key, &val); |
534 | if (found < 0) { |
535 | return NULL; |
536 | } |
537 | if (found == 0) { |
538 | PyErr_SetObject(PyExc_KeyError, key); |
539 | return NULL; |
540 | } |
541 | Py_INCREF(val); |
542 | return val; |
543 | } |
544 | |
545 | static int |
546 | context_tp_contains(PyContext *self, PyObject *key) |
547 | { |
548 | if (context_check_key_type(key)) { |
549 | return -1; |
550 | } |
551 | PyObject *val = NULL; |
552 | return _PyHamt_Find(self->ctx_vars, key, &val); |
553 | } |
554 | |
555 | |
556 | /*[clinic input] |
557 | _contextvars.Context.get |
558 | key: object |
559 | default: object = None |
560 | / |
561 | |
562 | Return the value for `key` if `key` has the value in the context object. |
563 | |
564 | If `key` does not exist, return `default`. If `default` is not given, |
565 | return None. |
566 | [clinic start generated code]*/ |
567 | |
568 | static PyObject * |
569 | _contextvars_Context_get_impl(PyContext *self, PyObject *key, |
570 | PyObject *default_value) |
571 | /*[clinic end generated code: output=0c54aa7664268189 input=c8eeb81505023995]*/ |
572 | { |
573 | if (context_check_key_type(key)) { |
574 | return NULL; |
575 | } |
576 | |
577 | PyObject *val = NULL; |
578 | int found = _PyHamt_Find(self->ctx_vars, key, &val); |
579 | if (found < 0) { |
580 | return NULL; |
581 | } |
582 | if (found == 0) { |
583 | Py_INCREF(default_value); |
584 | return default_value; |
585 | } |
586 | Py_INCREF(val); |
587 | return val; |
588 | } |
589 | |
590 | |
591 | /*[clinic input] |
592 | _contextvars.Context.items |
593 | |
594 | Return all variables and their values in the context object. |
595 | |
596 | The result is returned as a list of 2-tuples (variable, value). |
597 | [clinic start generated code]*/ |
598 | |
599 | static PyObject * |
600 | _contextvars_Context_items_impl(PyContext *self) |
601 | /*[clinic end generated code: output=fa1655c8a08502af input=00db64ae379f9f42]*/ |
602 | { |
603 | return _PyHamt_NewIterItems(self->ctx_vars); |
604 | } |
605 | |
606 | |
607 | /*[clinic input] |
608 | _contextvars.Context.keys |
609 | |
610 | Return a list of all variables in the context object. |
611 | [clinic start generated code]*/ |
612 | |
613 | static PyObject * |
614 | _contextvars_Context_keys_impl(PyContext *self) |
615 | /*[clinic end generated code: output=177227c6b63ec0e2 input=114b53aebca3449c]*/ |
616 | { |
617 | return _PyHamt_NewIterKeys(self->ctx_vars); |
618 | } |
619 | |
620 | |
621 | /*[clinic input] |
622 | _contextvars.Context.values |
623 | |
624 | Return a list of all variables' values in the context object. |
625 | [clinic start generated code]*/ |
626 | |
627 | static PyObject * |
628 | _contextvars_Context_values_impl(PyContext *self) |
629 | /*[clinic end generated code: output=d286dabfc8db6dde input=ce8075d04a6ea526]*/ |
630 | { |
631 | return _PyHamt_NewIterValues(self->ctx_vars); |
632 | } |
633 | |
634 | |
635 | /*[clinic input] |
636 | _contextvars.Context.copy |
637 | |
638 | Return a shallow copy of the context object. |
639 | [clinic start generated code]*/ |
640 | |
641 | static PyObject * |
642 | _contextvars_Context_copy_impl(PyContext *self) |
643 | /*[clinic end generated code: output=30ba8896c4707a15 input=ebafdbdd9c72d592]*/ |
644 | { |
645 | return (PyObject *)context_new_from_vars(self->ctx_vars); |
646 | } |
647 | |
648 | |
649 | static PyObject * |
650 | context_run(PyContext *self, PyObject *const *args, |
651 | Py_ssize_t nargs, PyObject *kwnames) |
652 | { |
653 | PyThreadState *ts = _PyThreadState_GET(); |
654 | |
655 | if (nargs < 1) { |
656 | _PyErr_SetString(ts, PyExc_TypeError, |
657 | "run() missing 1 required positional argument" ); |
658 | return NULL; |
659 | } |
660 | |
661 | if (_PyContext_Enter(ts, (PyObject *)self)) { |
662 | return NULL; |
663 | } |
664 | |
665 | PyObject *call_result = _PyObject_VectorcallTstate( |
666 | ts, args[0], args + 1, nargs - 1, kwnames); |
667 | |
668 | if (_PyContext_Exit(ts, (PyObject *)self)) { |
669 | return NULL; |
670 | } |
671 | |
672 | return call_result; |
673 | } |
674 | |
675 | |
676 | static PyMethodDef PyContext_methods[] = { |
677 | _CONTEXTVARS_CONTEXT_GET_METHODDEF |
678 | _CONTEXTVARS_CONTEXT_ITEMS_METHODDEF |
679 | _CONTEXTVARS_CONTEXT_KEYS_METHODDEF |
680 | _CONTEXTVARS_CONTEXT_VALUES_METHODDEF |
681 | _CONTEXTVARS_CONTEXT_COPY_METHODDEF |
682 | {"run" , (PyCFunction)(void(*)(void))context_run, METH_FASTCALL | METH_KEYWORDS, NULL}, |
683 | {NULL, NULL} |
684 | }; |
685 | |
686 | static PySequenceMethods PyContext_as_sequence = { |
687 | 0, /* sq_length */ |
688 | 0, /* sq_concat */ |
689 | 0, /* sq_repeat */ |
690 | 0, /* sq_item */ |
691 | 0, /* sq_slice */ |
692 | 0, /* sq_ass_item */ |
693 | 0, /* sq_ass_slice */ |
694 | (objobjproc)context_tp_contains, /* sq_contains */ |
695 | 0, /* sq_inplace_concat */ |
696 | 0, /* sq_inplace_repeat */ |
697 | }; |
698 | |
699 | static PyMappingMethods PyContext_as_mapping = { |
700 | (lenfunc)context_tp_len, /* mp_length */ |
701 | (binaryfunc)context_tp_subscript, /* mp_subscript */ |
702 | }; |
703 | |
704 | PyTypeObject PyContext_Type = { |
705 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
706 | "_contextvars.Context" , |
707 | sizeof(PyContext), |
708 | .tp_methods = PyContext_methods, |
709 | .tp_as_mapping = &PyContext_as_mapping, |
710 | .tp_as_sequence = &PyContext_as_sequence, |
711 | .tp_iter = (getiterfunc)context_tp_iter, |
712 | .tp_dealloc = (destructor)context_tp_dealloc, |
713 | .tp_getattro = PyObject_GenericGetAttr, |
714 | .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, |
715 | .tp_richcompare = context_tp_richcompare, |
716 | .tp_traverse = (traverseproc)context_tp_traverse, |
717 | .tp_clear = (inquiry)context_tp_clear, |
718 | .tp_new = context_tp_new, |
719 | .tp_weaklistoffset = offsetof(PyContext, ctx_weakreflist), |
720 | .tp_hash = PyObject_HashNotImplemented, |
721 | }; |
722 | |
723 | |
724 | /////////////////////////// ContextVar |
725 | |
726 | |
727 | static int |
728 | contextvar_set(PyContextVar *var, PyObject *val) |
729 | { |
730 | var->var_cached = NULL; |
731 | PyThreadState *ts = PyThreadState_Get(); |
732 | |
733 | PyContext *ctx = context_get(); |
734 | if (ctx == NULL) { |
735 | return -1; |
736 | } |
737 | |
738 | PyHamtObject *new_vars = _PyHamt_Assoc( |
739 | ctx->ctx_vars, (PyObject *)var, val); |
740 | if (new_vars == NULL) { |
741 | return -1; |
742 | } |
743 | |
744 | Py_SETREF(ctx->ctx_vars, new_vars); |
745 | |
746 | var->var_cached = val; /* borrow */ |
747 | var->var_cached_tsid = ts->id; |
748 | var->var_cached_tsver = ts->context_ver; |
749 | return 0; |
750 | } |
751 | |
752 | static int |
753 | contextvar_del(PyContextVar *var) |
754 | { |
755 | var->var_cached = NULL; |
756 | |
757 | PyContext *ctx = context_get(); |
758 | if (ctx == NULL) { |
759 | return -1; |
760 | } |
761 | |
762 | PyHamtObject *vars = ctx->ctx_vars; |
763 | PyHamtObject *new_vars = _PyHamt_Without(vars, (PyObject *)var); |
764 | if (new_vars == NULL) { |
765 | return -1; |
766 | } |
767 | |
768 | if (vars == new_vars) { |
769 | Py_DECREF(new_vars); |
770 | PyErr_SetObject(PyExc_LookupError, (PyObject *)var); |
771 | return -1; |
772 | } |
773 | |
774 | Py_SETREF(ctx->ctx_vars, new_vars); |
775 | return 0; |
776 | } |
777 | |
778 | static Py_hash_t |
779 | contextvar_generate_hash(void *addr, PyObject *name) |
780 | { |
781 | /* Take hash of `name` and XOR it with the object's addr. |
782 | |
783 | The structure of the tree is encoded in objects' hashes, which |
784 | means that sufficiently similar hashes would result in tall trees |
785 | with many Collision nodes. Which would, in turn, result in slower |
786 | get and set operations. |
787 | |
788 | The XORing helps to ensure that: |
789 | |
790 | (1) sequentially allocated ContextVar objects have |
791 | different hashes; |
792 | |
793 | (2) context variables with equal names have |
794 | different hashes. |
795 | */ |
796 | |
797 | Py_hash_t name_hash = PyObject_Hash(name); |
798 | if (name_hash == -1) { |
799 | return -1; |
800 | } |
801 | |
802 | Py_hash_t res = _Py_HashPointer(addr) ^ name_hash; |
803 | return res == -1 ? -2 : res; |
804 | } |
805 | |
806 | static PyContextVar * |
807 | contextvar_new(PyObject *name, PyObject *def) |
808 | { |
809 | if (!PyUnicode_Check(name)) { |
810 | PyErr_SetString(PyExc_TypeError, |
811 | "context variable name must be a str" ); |
812 | return NULL; |
813 | } |
814 | |
815 | PyContextVar *var = PyObject_GC_New(PyContextVar, &PyContextVar_Type); |
816 | if (var == NULL) { |
817 | return NULL; |
818 | } |
819 | |
820 | var->var_hash = contextvar_generate_hash(var, name); |
821 | if (var->var_hash == -1) { |
822 | Py_DECREF(var); |
823 | return NULL; |
824 | } |
825 | |
826 | Py_INCREF(name); |
827 | var->var_name = name; |
828 | |
829 | Py_XINCREF(def); |
830 | var->var_default = def; |
831 | |
832 | var->var_cached = NULL; |
833 | var->var_cached_tsid = 0; |
834 | var->var_cached_tsver = 0; |
835 | |
836 | if (_PyObject_GC_MAY_BE_TRACKED(name) || |
837 | (def != NULL && _PyObject_GC_MAY_BE_TRACKED(def))) |
838 | { |
839 | PyObject_GC_Track(var); |
840 | } |
841 | return var; |
842 | } |
843 | |
844 | |
845 | /*[clinic input] |
846 | class _contextvars.ContextVar "PyContextVar *" "&PyContextVar_Type" |
847 | [clinic start generated code]*/ |
848 | /*[clinic end generated code: output=da39a3ee5e6b4b0d input=445da935fa8883c3]*/ |
849 | |
850 | |
851 | static PyObject * |
852 | contextvar_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds) |
853 | { |
854 | static char *kwlist[] = {"" , "default" , NULL}; |
855 | PyObject *name; |
856 | PyObject *def = NULL; |
857 | |
858 | if (!PyArg_ParseTupleAndKeywords( |
859 | args, kwds, "O|$O:ContextVar" , kwlist, &name, &def)) |
860 | { |
861 | return NULL; |
862 | } |
863 | |
864 | return (PyObject *)contextvar_new(name, def); |
865 | } |
866 | |
867 | static int |
868 | contextvar_tp_clear(PyContextVar *self) |
869 | { |
870 | Py_CLEAR(self->var_name); |
871 | Py_CLEAR(self->var_default); |
872 | self->var_cached = NULL; |
873 | self->var_cached_tsid = 0; |
874 | self->var_cached_tsver = 0; |
875 | return 0; |
876 | } |
877 | |
878 | static int |
879 | contextvar_tp_traverse(PyContextVar *self, visitproc visit, void *arg) |
880 | { |
881 | Py_VISIT(self->var_name); |
882 | Py_VISIT(self->var_default); |
883 | return 0; |
884 | } |
885 | |
886 | static void |
887 | contextvar_tp_dealloc(PyContextVar *self) |
888 | { |
889 | PyObject_GC_UnTrack(self); |
890 | (void)contextvar_tp_clear(self); |
891 | Py_TYPE(self)->tp_free(self); |
892 | } |
893 | |
894 | static Py_hash_t |
895 | contextvar_tp_hash(PyContextVar *self) |
896 | { |
897 | return self->var_hash; |
898 | } |
899 | |
900 | static PyObject * |
901 | contextvar_tp_repr(PyContextVar *self) |
902 | { |
903 | _PyUnicodeWriter writer; |
904 | |
905 | _PyUnicodeWriter_Init(&writer); |
906 | |
907 | if (_PyUnicodeWriter_WriteASCIIString( |
908 | &writer, "<ContextVar name=" , 17) < 0) |
909 | { |
910 | goto error; |
911 | } |
912 | |
913 | PyObject *name = PyObject_Repr(self->var_name); |
914 | if (name == NULL) { |
915 | goto error; |
916 | } |
917 | if (_PyUnicodeWriter_WriteStr(&writer, name) < 0) { |
918 | Py_DECREF(name); |
919 | goto error; |
920 | } |
921 | Py_DECREF(name); |
922 | |
923 | if (self->var_default != NULL) { |
924 | if (_PyUnicodeWriter_WriteASCIIString(&writer, " default=" , 9) < 0) { |
925 | goto error; |
926 | } |
927 | |
928 | PyObject *def = PyObject_Repr(self->var_default); |
929 | if (def == NULL) { |
930 | goto error; |
931 | } |
932 | if (_PyUnicodeWriter_WriteStr(&writer, def) < 0) { |
933 | Py_DECREF(def); |
934 | goto error; |
935 | } |
936 | Py_DECREF(def); |
937 | } |
938 | |
939 | PyObject *addr = PyUnicode_FromFormat(" at %p>" , self); |
940 | if (addr == NULL) { |
941 | goto error; |
942 | } |
943 | if (_PyUnicodeWriter_WriteStr(&writer, addr) < 0) { |
944 | Py_DECREF(addr); |
945 | goto error; |
946 | } |
947 | Py_DECREF(addr); |
948 | |
949 | return _PyUnicodeWriter_Finish(&writer); |
950 | |
951 | error: |
952 | _PyUnicodeWriter_Dealloc(&writer); |
953 | return NULL; |
954 | } |
955 | |
956 | |
957 | /*[clinic input] |
958 | _contextvars.ContextVar.get |
959 | default: object = NULL |
960 | / |
961 | |
962 | Return a value for the context variable for the current context. |
963 | |
964 | If there is no value for the variable in the current context, the method will: |
965 | * return the value of the default argument of the method, if provided; or |
966 | * return the default value for the context variable, if it was created |
967 | with one; or |
968 | * raise a LookupError. |
969 | [clinic start generated code]*/ |
970 | |
971 | static PyObject * |
972 | _contextvars_ContextVar_get_impl(PyContextVar *self, PyObject *default_value) |
973 | /*[clinic end generated code: output=0746bd0aa2ced7bf input=30aa2ab9e433e401]*/ |
974 | { |
975 | if (!PyContextVar_CheckExact(self)) { |
976 | PyErr_SetString( |
977 | PyExc_TypeError, "an instance of ContextVar was expected" ); |
978 | return NULL; |
979 | } |
980 | |
981 | PyObject *val; |
982 | if (PyContextVar_Get((PyObject *)self, default_value, &val) < 0) { |
983 | return NULL; |
984 | } |
985 | |
986 | if (val == NULL) { |
987 | PyErr_SetObject(PyExc_LookupError, (PyObject *)self); |
988 | return NULL; |
989 | } |
990 | |
991 | return val; |
992 | } |
993 | |
994 | /*[clinic input] |
995 | _contextvars.ContextVar.set |
996 | value: object |
997 | / |
998 | |
999 | Call to set a new value for the context variable in the current context. |
1000 | |
1001 | The required value argument is the new value for the context variable. |
1002 | |
1003 | Returns a Token object that can be used to restore the variable to its previous |
1004 | value via the `ContextVar.reset()` method. |
1005 | [clinic start generated code]*/ |
1006 | |
1007 | static PyObject * |
1008 | _contextvars_ContextVar_set(PyContextVar *self, PyObject *value) |
1009 | /*[clinic end generated code: output=446ed5e820d6d60b input=c0a6887154227453]*/ |
1010 | { |
1011 | return PyContextVar_Set((PyObject *)self, value); |
1012 | } |
1013 | |
1014 | /*[clinic input] |
1015 | _contextvars.ContextVar.reset |
1016 | token: object |
1017 | / |
1018 | |
1019 | Reset the context variable. |
1020 | |
1021 | The variable is reset to the value it had before the `ContextVar.set()` that |
1022 | created the token was used. |
1023 | [clinic start generated code]*/ |
1024 | |
1025 | static PyObject * |
1026 | _contextvars_ContextVar_reset(PyContextVar *self, PyObject *token) |
1027 | /*[clinic end generated code: output=d4ee34d0742d62ee input=ebe2881e5af4ffda]*/ |
1028 | { |
1029 | if (!PyContextToken_CheckExact(token)) { |
1030 | PyErr_Format(PyExc_TypeError, |
1031 | "expected an instance of Token, got %R" , token); |
1032 | return NULL; |
1033 | } |
1034 | |
1035 | if (PyContextVar_Reset((PyObject *)self, token)) { |
1036 | return NULL; |
1037 | } |
1038 | |
1039 | Py_RETURN_NONE; |
1040 | } |
1041 | |
1042 | |
1043 | static PyMemberDef PyContextVar_members[] = { |
1044 | {"name" , T_OBJECT, offsetof(PyContextVar, var_name), READONLY}, |
1045 | {NULL} |
1046 | }; |
1047 | |
1048 | static PyMethodDef PyContextVar_methods[] = { |
1049 | _CONTEXTVARS_CONTEXTVAR_GET_METHODDEF |
1050 | _CONTEXTVARS_CONTEXTVAR_SET_METHODDEF |
1051 | _CONTEXTVARS_CONTEXTVAR_RESET_METHODDEF |
1052 | {"__class_getitem__" , (PyCFunction)Py_GenericAlias, |
1053 | METH_O|METH_CLASS, PyDoc_STR("See PEP 585" )}, |
1054 | {NULL, NULL} |
1055 | }; |
1056 | |
1057 | PyTypeObject PyContextVar_Type = { |
1058 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
1059 | "_contextvars.ContextVar" , |
1060 | sizeof(PyContextVar), |
1061 | .tp_methods = PyContextVar_methods, |
1062 | .tp_members = PyContextVar_members, |
1063 | .tp_dealloc = (destructor)contextvar_tp_dealloc, |
1064 | .tp_getattro = PyObject_GenericGetAttr, |
1065 | .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, |
1066 | .tp_traverse = (traverseproc)contextvar_tp_traverse, |
1067 | .tp_clear = (inquiry)contextvar_tp_clear, |
1068 | .tp_new = contextvar_tp_new, |
1069 | .tp_free = PyObject_GC_Del, |
1070 | .tp_hash = (hashfunc)contextvar_tp_hash, |
1071 | .tp_repr = (reprfunc)contextvar_tp_repr, |
1072 | }; |
1073 | |
1074 | |
1075 | /////////////////////////// Token |
1076 | |
1077 | static PyObject * get_token_missing(void); |
1078 | |
1079 | |
1080 | /*[clinic input] |
1081 | class _contextvars.Token "PyContextToken *" "&PyContextToken_Type" |
1082 | [clinic start generated code]*/ |
1083 | /*[clinic end generated code: output=da39a3ee5e6b4b0d input=338a5e2db13d3f5b]*/ |
1084 | |
1085 | |
1086 | static PyObject * |
1087 | token_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds) |
1088 | { |
1089 | PyErr_SetString(PyExc_RuntimeError, |
1090 | "Tokens can only be created by ContextVars" ); |
1091 | return NULL; |
1092 | } |
1093 | |
1094 | static int |
1095 | token_tp_clear(PyContextToken *self) |
1096 | { |
1097 | Py_CLEAR(self->tok_ctx); |
1098 | Py_CLEAR(self->tok_var); |
1099 | Py_CLEAR(self->tok_oldval); |
1100 | return 0; |
1101 | } |
1102 | |
1103 | static int |
1104 | token_tp_traverse(PyContextToken *self, visitproc visit, void *arg) |
1105 | { |
1106 | Py_VISIT(self->tok_ctx); |
1107 | Py_VISIT(self->tok_var); |
1108 | Py_VISIT(self->tok_oldval); |
1109 | return 0; |
1110 | } |
1111 | |
1112 | static void |
1113 | token_tp_dealloc(PyContextToken *self) |
1114 | { |
1115 | PyObject_GC_UnTrack(self); |
1116 | (void)token_tp_clear(self); |
1117 | Py_TYPE(self)->tp_free(self); |
1118 | } |
1119 | |
1120 | static PyObject * |
1121 | token_tp_repr(PyContextToken *self) |
1122 | { |
1123 | _PyUnicodeWriter writer; |
1124 | |
1125 | _PyUnicodeWriter_Init(&writer); |
1126 | |
1127 | if (_PyUnicodeWriter_WriteASCIIString(&writer, "<Token" , 6) < 0) { |
1128 | goto error; |
1129 | } |
1130 | |
1131 | if (self->tok_used) { |
1132 | if (_PyUnicodeWriter_WriteASCIIString(&writer, " used" , 5) < 0) { |
1133 | goto error; |
1134 | } |
1135 | } |
1136 | |
1137 | if (_PyUnicodeWriter_WriteASCIIString(&writer, " var=" , 5) < 0) { |
1138 | goto error; |
1139 | } |
1140 | |
1141 | PyObject *var = PyObject_Repr((PyObject *)self->tok_var); |
1142 | if (var == NULL) { |
1143 | goto error; |
1144 | } |
1145 | if (_PyUnicodeWriter_WriteStr(&writer, var) < 0) { |
1146 | Py_DECREF(var); |
1147 | goto error; |
1148 | } |
1149 | Py_DECREF(var); |
1150 | |
1151 | PyObject *addr = PyUnicode_FromFormat(" at %p>" , self); |
1152 | if (addr == NULL) { |
1153 | goto error; |
1154 | } |
1155 | if (_PyUnicodeWriter_WriteStr(&writer, addr) < 0) { |
1156 | Py_DECREF(addr); |
1157 | goto error; |
1158 | } |
1159 | Py_DECREF(addr); |
1160 | |
1161 | return _PyUnicodeWriter_Finish(&writer); |
1162 | |
1163 | error: |
1164 | _PyUnicodeWriter_Dealloc(&writer); |
1165 | return NULL; |
1166 | } |
1167 | |
1168 | static PyObject * |
1169 | token_get_var(PyContextToken *self, void *Py_UNUSED(ignored)) |
1170 | { |
1171 | Py_INCREF(self->tok_var); |
1172 | return (PyObject *)self->tok_var; |
1173 | } |
1174 | |
1175 | static PyObject * |
1176 | token_get_old_value(PyContextToken *self, void *Py_UNUSED(ignored)) |
1177 | { |
1178 | if (self->tok_oldval == NULL) { |
1179 | return get_token_missing(); |
1180 | } |
1181 | |
1182 | Py_INCREF(self->tok_oldval); |
1183 | return self->tok_oldval; |
1184 | } |
1185 | |
1186 | static PyGetSetDef PyContextTokenType_getsetlist[] = { |
1187 | {"var" , (getter)token_get_var, NULL, NULL}, |
1188 | {"old_value" , (getter)token_get_old_value, NULL, NULL}, |
1189 | {NULL} |
1190 | }; |
1191 | |
1192 | static PyMethodDef PyContextTokenType_methods[] = { |
1193 | {"__class_getitem__" , (PyCFunction)Py_GenericAlias, |
1194 | METH_O|METH_CLASS, PyDoc_STR("See PEP 585" )}, |
1195 | {NULL} |
1196 | }; |
1197 | |
1198 | PyTypeObject PyContextToken_Type = { |
1199 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
1200 | "_contextvars.Token" , |
1201 | sizeof(PyContextToken), |
1202 | .tp_methods = PyContextTokenType_methods, |
1203 | .tp_getset = PyContextTokenType_getsetlist, |
1204 | .tp_dealloc = (destructor)token_tp_dealloc, |
1205 | .tp_getattro = PyObject_GenericGetAttr, |
1206 | .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, |
1207 | .tp_traverse = (traverseproc)token_tp_traverse, |
1208 | .tp_clear = (inquiry)token_tp_clear, |
1209 | .tp_new = token_tp_new, |
1210 | .tp_free = PyObject_GC_Del, |
1211 | .tp_hash = PyObject_HashNotImplemented, |
1212 | .tp_repr = (reprfunc)token_tp_repr, |
1213 | }; |
1214 | |
1215 | static PyContextToken * |
1216 | token_new(PyContext *ctx, PyContextVar *var, PyObject *val) |
1217 | { |
1218 | PyContextToken *tok = PyObject_GC_New(PyContextToken, &PyContextToken_Type); |
1219 | if (tok == NULL) { |
1220 | return NULL; |
1221 | } |
1222 | |
1223 | Py_INCREF(ctx); |
1224 | tok->tok_ctx = ctx; |
1225 | |
1226 | Py_INCREF(var); |
1227 | tok->tok_var = var; |
1228 | |
1229 | Py_XINCREF(val); |
1230 | tok->tok_oldval = val; |
1231 | |
1232 | tok->tok_used = 0; |
1233 | |
1234 | PyObject_GC_Track(tok); |
1235 | return tok; |
1236 | } |
1237 | |
1238 | |
1239 | /////////////////////////// Token.MISSING |
1240 | |
1241 | |
1242 | static PyObject *_token_missing; |
1243 | |
1244 | |
1245 | typedef struct { |
1246 | PyObject_HEAD |
1247 | } PyContextTokenMissing; |
1248 | |
1249 | |
1250 | static PyObject * |
1251 | context_token_missing_tp_repr(PyObject *self) |
1252 | { |
1253 | return PyUnicode_FromString("<Token.MISSING>" ); |
1254 | } |
1255 | |
1256 | |
1257 | PyTypeObject PyContextTokenMissing_Type = { |
1258 | PyVarObject_HEAD_INIT(&PyType_Type, 0) |
1259 | "Token.MISSING" , |
1260 | sizeof(PyContextTokenMissing), |
1261 | .tp_getattro = PyObject_GenericGetAttr, |
1262 | .tp_flags = Py_TPFLAGS_DEFAULT, |
1263 | .tp_repr = context_token_missing_tp_repr, |
1264 | }; |
1265 | |
1266 | |
1267 | static PyObject * |
1268 | get_token_missing(void) |
1269 | { |
1270 | if (_token_missing != NULL) { |
1271 | Py_INCREF(_token_missing); |
1272 | return _token_missing; |
1273 | } |
1274 | |
1275 | _token_missing = (PyObject *)PyObject_New( |
1276 | PyContextTokenMissing, &PyContextTokenMissing_Type); |
1277 | if (_token_missing == NULL) { |
1278 | return NULL; |
1279 | } |
1280 | |
1281 | Py_INCREF(_token_missing); |
1282 | return _token_missing; |
1283 | } |
1284 | |
1285 | |
1286 | /////////////////////////// |
1287 | |
1288 | |
1289 | void |
1290 | _PyContext_ClearFreeList(PyInterpreterState *interp) |
1291 | { |
1292 | struct _Py_context_state *state = &interp->context; |
1293 | for (; state->numfree; state->numfree--) { |
1294 | PyContext *ctx = state->freelist; |
1295 | state->freelist = (PyContext *)ctx->ctx_weakreflist; |
1296 | ctx->ctx_weakreflist = NULL; |
1297 | PyObject_GC_Del(ctx); |
1298 | } |
1299 | } |
1300 | |
1301 | |
1302 | void |
1303 | _PyContext_Fini(PyInterpreterState *interp) |
1304 | { |
1305 | if (_Py_IsMainInterpreter(interp)) { |
1306 | Py_CLEAR(_token_missing); |
1307 | } |
1308 | _PyContext_ClearFreeList(interp); |
1309 | #ifdef Py_DEBUG |
1310 | struct _Py_context_state *state = &interp->context; |
1311 | state->numfree = -1; |
1312 | #endif |
1313 | _PyHamt_Fini(); |
1314 | } |
1315 | |
1316 | |
1317 | int |
1318 | _PyContext_Init(void) |
1319 | { |
1320 | if (!_PyHamt_Init()) { |
1321 | return 0; |
1322 | } |
1323 | |
1324 | if ((PyType_Ready(&PyContext_Type) < 0) || |
1325 | (PyType_Ready(&PyContextVar_Type) < 0) || |
1326 | (PyType_Ready(&PyContextToken_Type) < 0) || |
1327 | (PyType_Ready(&PyContextTokenMissing_Type) < 0)) |
1328 | { |
1329 | return 0; |
1330 | } |
1331 | |
1332 | PyObject *missing = get_token_missing(); |
1333 | if (PyDict_SetItemString( |
1334 | PyContextToken_Type.tp_dict, "MISSING" , missing)) |
1335 | { |
1336 | Py_DECREF(missing); |
1337 | return 0; |
1338 | } |
1339 | Py_DECREF(missing); |
1340 | |
1341 | return 1; |
1342 | } |
1343 | |