1 | #include "Python.h" |
2 | #include "pycore_moduleobject.h" // _PyModule_GetState() |
3 | #include "structmember.h" // PyMemberDef |
4 | #include <stddef.h> // offsetof() |
5 | |
6 | typedef struct { |
7 | PyTypeObject *SimpleQueueType; |
8 | PyObject *EmptyError; |
9 | } simplequeue_state; |
10 | |
11 | static simplequeue_state * |
12 | simplequeue_get_state(PyObject *module) |
13 | { |
14 | simplequeue_state *state = _PyModule_GetState(module); |
15 | assert(state); |
16 | return state; |
17 | } |
18 | static struct PyModuleDef queuemodule; |
19 | #define simplequeue_get_state_by_type(type) \ |
20 | (simplequeue_get_state(_PyType_GetModuleByDef(type, &queuemodule))) |
21 | |
22 | typedef struct { |
23 | PyObject_HEAD |
24 | PyThread_type_lock lock; |
25 | int locked; |
26 | PyObject *lst; |
27 | Py_ssize_t lst_pos; |
28 | PyObject *weakreflist; |
29 | } simplequeueobject; |
30 | |
31 | /*[clinic input] |
32 | module _queue |
33 | class _queue.SimpleQueue "simplequeueobject *" "simplequeue_get_state_by_type(type)->SimpleQueueType" |
34 | [clinic start generated code]*/ |
35 | /*[clinic end generated code: output=da39a3ee5e6b4b0d input=0a4023fe4d198c8d]*/ |
36 | |
37 | static int |
38 | simplequeue_clear(simplequeueobject *self) |
39 | { |
40 | Py_CLEAR(self->lst); |
41 | return 0; |
42 | } |
43 | |
44 | static void |
45 | simplequeue_dealloc(simplequeueobject *self) |
46 | { |
47 | PyTypeObject *tp = Py_TYPE(self); |
48 | |
49 | PyObject_GC_UnTrack(self); |
50 | if (self->lock != NULL) { |
51 | /* Unlock the lock so it's safe to free it */ |
52 | if (self->locked > 0) |
53 | PyThread_release_lock(self->lock); |
54 | PyThread_free_lock(self->lock); |
55 | } |
56 | (void)simplequeue_clear(self); |
57 | if (self->weakreflist != NULL) |
58 | PyObject_ClearWeakRefs((PyObject *) self); |
59 | Py_TYPE(self)->tp_free(self); |
60 | Py_DECREF(tp); |
61 | } |
62 | |
63 | static int |
64 | simplequeue_traverse(simplequeueobject *self, visitproc visit, void *arg) |
65 | { |
66 | Py_VISIT(self->lst); |
67 | Py_VISIT(Py_TYPE(self)); |
68 | return 0; |
69 | } |
70 | |
71 | /*[clinic input] |
72 | @classmethod |
73 | _queue.SimpleQueue.__new__ as simplequeue_new |
74 | |
75 | Simple, unbounded, reentrant FIFO queue. |
76 | [clinic start generated code]*/ |
77 | |
78 | static PyObject * |
79 | simplequeue_new_impl(PyTypeObject *type) |
80 | /*[clinic end generated code: output=ba97740608ba31cd input=a0674a1643e3e2fb]*/ |
81 | { |
82 | simplequeueobject *self; |
83 | |
84 | self = (simplequeueobject *) type->tp_alloc(type, 0); |
85 | if (self != NULL) { |
86 | self->weakreflist = NULL; |
87 | self->lst = PyList_New(0); |
88 | self->lock = PyThread_allocate_lock(); |
89 | self->lst_pos = 0; |
90 | if (self->lock == NULL) { |
91 | Py_DECREF(self); |
92 | PyErr_SetString(PyExc_MemoryError, "can't allocate lock" ); |
93 | return NULL; |
94 | } |
95 | if (self->lst == NULL) { |
96 | Py_DECREF(self); |
97 | return NULL; |
98 | } |
99 | } |
100 | |
101 | return (PyObject *) self; |
102 | } |
103 | |
104 | /*[clinic input] |
105 | _queue.SimpleQueue.put |
106 | item: object |
107 | block: bool = True |
108 | timeout: object = None |
109 | |
110 | Put the item on the queue. |
111 | |
112 | The optional 'block' and 'timeout' arguments are ignored, as this method |
113 | never blocks. They are provided for compatibility with the Queue class. |
114 | |
115 | [clinic start generated code]*/ |
116 | |
117 | static PyObject * |
118 | _queue_SimpleQueue_put_impl(simplequeueobject *self, PyObject *item, |
119 | int block, PyObject *timeout) |
120 | /*[clinic end generated code: output=4333136e88f90d8b input=6e601fa707a782d5]*/ |
121 | { |
122 | /* BEGIN GIL-protected critical section */ |
123 | if (PyList_Append(self->lst, item) < 0) |
124 | return NULL; |
125 | if (self->locked) { |
126 | /* A get() may be waiting, wake it up */ |
127 | self->locked = 0; |
128 | PyThread_release_lock(self->lock); |
129 | } |
130 | /* END GIL-protected critical section */ |
131 | Py_RETURN_NONE; |
132 | } |
133 | |
134 | /*[clinic input] |
135 | _queue.SimpleQueue.put_nowait |
136 | item: object |
137 | |
138 | Put an item into the queue without blocking. |
139 | |
140 | This is exactly equivalent to `put(item)` and is only provided |
141 | for compatibility with the Queue class. |
142 | |
143 | [clinic start generated code]*/ |
144 | |
145 | static PyObject * |
146 | _queue_SimpleQueue_put_nowait_impl(simplequeueobject *self, PyObject *item) |
147 | /*[clinic end generated code: output=0990536715efb1f1 input=36b1ea96756b2ece]*/ |
148 | { |
149 | return _queue_SimpleQueue_put_impl(self, item, 0, Py_None); |
150 | } |
151 | |
152 | static PyObject * |
153 | simplequeue_pop_item(simplequeueobject *self) |
154 | { |
155 | Py_ssize_t count, n; |
156 | PyObject *item; |
157 | |
158 | n = PyList_GET_SIZE(self->lst); |
159 | assert(self->lst_pos < n); |
160 | |
161 | item = PyList_GET_ITEM(self->lst, self->lst_pos); |
162 | Py_INCREF(Py_None); |
163 | PyList_SET_ITEM(self->lst, self->lst_pos, Py_None); |
164 | self->lst_pos += 1; |
165 | count = n - self->lst_pos; |
166 | if (self->lst_pos > count) { |
167 | /* The list is more than 50% empty, reclaim space at the beginning */ |
168 | if (PyList_SetSlice(self->lst, 0, self->lst_pos, NULL)) { |
169 | /* Undo pop */ |
170 | self->lst_pos -= 1; |
171 | PyList_SET_ITEM(self->lst, self->lst_pos, item); |
172 | return NULL; |
173 | } |
174 | self->lst_pos = 0; |
175 | } |
176 | return item; |
177 | } |
178 | |
179 | /*[clinic input] |
180 | _queue.SimpleQueue.get |
181 | |
182 | cls: defining_class |
183 | / |
184 | block: bool = True |
185 | timeout: object = None |
186 | |
187 | Remove and return an item from the queue. |
188 | |
189 | If optional args 'block' is true and 'timeout' is None (the default), |
190 | block if necessary until an item is available. If 'timeout' is |
191 | a non-negative number, it blocks at most 'timeout' seconds and raises |
192 | the Empty exception if no item was available within that time. |
193 | Otherwise ('block' is false), return an item if one is immediately |
194 | available, else raise the Empty exception ('timeout' is ignored |
195 | in that case). |
196 | |
197 | [clinic start generated code]*/ |
198 | |
199 | static PyObject * |
200 | _queue_SimpleQueue_get_impl(simplequeueobject *self, PyTypeObject *cls, |
201 | int block, PyObject *timeout) |
202 | /*[clinic end generated code: output=1969aefa7db63666 input=5fc4d56b9a54757e]*/ |
203 | { |
204 | _PyTime_t endtime = 0; |
205 | _PyTime_t timeout_val; |
206 | PyObject *item; |
207 | PyLockStatus r; |
208 | PY_TIMEOUT_T microseconds; |
209 | |
210 | if (block == 0) { |
211 | /* Non-blocking */ |
212 | microseconds = 0; |
213 | } |
214 | else if (timeout != Py_None) { |
215 | /* With timeout */ |
216 | if (_PyTime_FromSecondsObject(&timeout_val, |
217 | timeout, _PyTime_ROUND_CEILING) < 0) |
218 | return NULL; |
219 | if (timeout_val < 0) { |
220 | PyErr_SetString(PyExc_ValueError, |
221 | "'timeout' must be a non-negative number" ); |
222 | return NULL; |
223 | } |
224 | microseconds = _PyTime_AsMicroseconds(timeout_val, |
225 | _PyTime_ROUND_CEILING); |
226 | if (microseconds >= PY_TIMEOUT_MAX) { |
227 | PyErr_SetString(PyExc_OverflowError, |
228 | "timeout value is too large" ); |
229 | return NULL; |
230 | } |
231 | endtime = _PyTime_GetMonotonicClock() + timeout_val; |
232 | } |
233 | else { |
234 | /* Infinitely blocking */ |
235 | microseconds = -1; |
236 | } |
237 | |
238 | /* put() signals the queue to be non-empty by releasing the lock. |
239 | * So we simply try to acquire the lock in a loop, until the condition |
240 | * (queue non-empty) becomes true. |
241 | */ |
242 | while (self->lst_pos == PyList_GET_SIZE(self->lst)) { |
243 | /* First a simple non-blocking try without releasing the GIL */ |
244 | r = PyThread_acquire_lock_timed(self->lock, 0, 0); |
245 | if (r == PY_LOCK_FAILURE && microseconds != 0) { |
246 | Py_BEGIN_ALLOW_THREADS |
247 | r = PyThread_acquire_lock_timed(self->lock, microseconds, 1); |
248 | Py_END_ALLOW_THREADS |
249 | } |
250 | if (r == PY_LOCK_INTR && Py_MakePendingCalls() < 0) { |
251 | return NULL; |
252 | } |
253 | if (r == PY_LOCK_FAILURE) { |
254 | PyObject *module = PyType_GetModule(cls); |
255 | simplequeue_state *state = simplequeue_get_state(module); |
256 | /* Timed out */ |
257 | PyErr_SetNone(state->EmptyError); |
258 | return NULL; |
259 | } |
260 | self->locked = 1; |
261 | /* Adjust timeout for next iteration (if any) */ |
262 | if (endtime > 0) { |
263 | timeout_val = endtime - _PyTime_GetMonotonicClock(); |
264 | microseconds = _PyTime_AsMicroseconds(timeout_val, _PyTime_ROUND_CEILING); |
265 | } |
266 | } |
267 | /* BEGIN GIL-protected critical section */ |
268 | assert(self->lst_pos < PyList_GET_SIZE(self->lst)); |
269 | item = simplequeue_pop_item(self); |
270 | if (self->locked) { |
271 | PyThread_release_lock(self->lock); |
272 | self->locked = 0; |
273 | } |
274 | /* END GIL-protected critical section */ |
275 | |
276 | return item; |
277 | } |
278 | |
279 | /*[clinic input] |
280 | _queue.SimpleQueue.get_nowait |
281 | |
282 | cls: defining_class |
283 | / |
284 | |
285 | Remove and return an item from the queue without blocking. |
286 | |
287 | Only get an item if one is immediately available. Otherwise |
288 | raise the Empty exception. |
289 | [clinic start generated code]*/ |
290 | |
291 | static PyObject * |
292 | _queue_SimpleQueue_get_nowait_impl(simplequeueobject *self, |
293 | PyTypeObject *cls) |
294 | /*[clinic end generated code: output=620c58e2750f8b8a input=842f732bf04216d3]*/ |
295 | { |
296 | return _queue_SimpleQueue_get_impl(self, cls, 0, Py_None); |
297 | } |
298 | |
299 | /*[clinic input] |
300 | _queue.SimpleQueue.empty -> bool |
301 | |
302 | Return True if the queue is empty, False otherwise (not reliable!). |
303 | [clinic start generated code]*/ |
304 | |
305 | static int |
306 | _queue_SimpleQueue_empty_impl(simplequeueobject *self) |
307 | /*[clinic end generated code: output=1a02a1b87c0ef838 input=1a98431c45fd66f9]*/ |
308 | { |
309 | return self->lst_pos == PyList_GET_SIZE(self->lst); |
310 | } |
311 | |
312 | /*[clinic input] |
313 | _queue.SimpleQueue.qsize -> Py_ssize_t |
314 | |
315 | Return the approximate size of the queue (not reliable!). |
316 | [clinic start generated code]*/ |
317 | |
318 | static Py_ssize_t |
319 | _queue_SimpleQueue_qsize_impl(simplequeueobject *self) |
320 | /*[clinic end generated code: output=f9dcd9d0a90e121e input=7a74852b407868a1]*/ |
321 | { |
322 | return PyList_GET_SIZE(self->lst) - self->lst_pos; |
323 | } |
324 | |
325 | static int |
326 | queue_traverse(PyObject *m, visitproc visit, void *arg) |
327 | { |
328 | simplequeue_state *state = simplequeue_get_state(m); |
329 | Py_VISIT(state->SimpleQueueType); |
330 | Py_VISIT(state->EmptyError); |
331 | return 0; |
332 | } |
333 | |
334 | static int |
335 | queue_clear(PyObject *m) |
336 | { |
337 | simplequeue_state *state = simplequeue_get_state(m); |
338 | Py_CLEAR(state->SimpleQueueType); |
339 | Py_CLEAR(state->EmptyError); |
340 | return 0; |
341 | } |
342 | |
343 | static void |
344 | queue_free(void *m) |
345 | { |
346 | queue_clear((PyObject *)m); |
347 | } |
348 | |
349 | #include "clinic/_queuemodule.c.h" |
350 | |
351 | |
352 | static PyMethodDef simplequeue_methods[] = { |
353 | _QUEUE_SIMPLEQUEUE_EMPTY_METHODDEF |
354 | _QUEUE_SIMPLEQUEUE_GET_METHODDEF |
355 | _QUEUE_SIMPLEQUEUE_GET_NOWAIT_METHODDEF |
356 | _QUEUE_SIMPLEQUEUE_PUT_METHODDEF |
357 | _QUEUE_SIMPLEQUEUE_PUT_NOWAIT_METHODDEF |
358 | _QUEUE_SIMPLEQUEUE_QSIZE_METHODDEF |
359 | {"__class_getitem__" , (PyCFunction)Py_GenericAlias, |
360 | METH_O|METH_CLASS, PyDoc_STR("See PEP 585" )}, |
361 | {NULL, NULL} /* sentinel */ |
362 | }; |
363 | |
364 | static struct PyMemberDef simplequeue_members[] = { |
365 | {"__weaklistoffset__" , T_PYSSIZET, offsetof(simplequeueobject, weakreflist), READONLY}, |
366 | {NULL}, |
367 | }; |
368 | |
369 | static PyType_Slot simplequeue_slots[] = { |
370 | {Py_tp_dealloc, simplequeue_dealloc}, |
371 | {Py_tp_doc, (void *)simplequeue_new__doc__}, |
372 | {Py_tp_traverse, simplequeue_traverse}, |
373 | {Py_tp_clear, simplequeue_clear}, |
374 | {Py_tp_members, simplequeue_members}, |
375 | {Py_tp_methods, simplequeue_methods}, |
376 | {Py_tp_new, simplequeue_new}, |
377 | {0, NULL}, |
378 | }; |
379 | |
380 | static PyType_Spec simplequeue_spec = { |
381 | .name = "_queue.SimpleQueue" , |
382 | .basicsize = sizeof(simplequeueobject), |
383 | .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC | |
384 | Py_TPFLAGS_IMMUTABLETYPE), |
385 | .slots = simplequeue_slots, |
386 | }; |
387 | |
388 | |
389 | /* Initialization function */ |
390 | |
391 | PyDoc_STRVAR(queue_module_doc, |
392 | "C implementation of the Python queue module.\n\ |
393 | This module is an implementation detail, please do not use it directly." ); |
394 | |
395 | static int |
396 | queuemodule_exec(PyObject *module) |
397 | { |
398 | simplequeue_state *state = simplequeue_get_state(module); |
399 | |
400 | state->EmptyError = PyErr_NewExceptionWithDoc( |
401 | "_queue.Empty" , |
402 | "Exception raised by Queue.get(block=0)/get_nowait()." , |
403 | NULL, NULL); |
404 | if (state->EmptyError == NULL) { |
405 | return -1; |
406 | } |
407 | if (PyModule_AddObjectRef(module, "Empty" , state->EmptyError) < 0) { |
408 | return -1; |
409 | } |
410 | |
411 | state->SimpleQueueType = (PyTypeObject *)PyType_FromModuleAndSpec( |
412 | module, &simplequeue_spec, NULL); |
413 | if (state->SimpleQueueType == NULL) { |
414 | return -1; |
415 | } |
416 | if (PyModule_AddType(module, state->SimpleQueueType) < 0) { |
417 | return -1; |
418 | } |
419 | |
420 | return 0; |
421 | } |
422 | |
423 | static PyModuleDef_Slot queuemodule_slots[] = { |
424 | {Py_mod_exec, queuemodule_exec}, |
425 | {0, NULL} |
426 | }; |
427 | |
428 | |
429 | static struct PyModuleDef queuemodule = { |
430 | .m_base = PyModuleDef_HEAD_INIT, |
431 | .m_name = "_queue" , |
432 | .m_doc = queue_module_doc, |
433 | .m_size = sizeof(simplequeue_state), |
434 | .m_slots = queuemodule_slots, |
435 | .m_traverse = queue_traverse, |
436 | .m_clear = queue_clear, |
437 | .m_free = queue_free, |
438 | }; |
439 | |
440 | |
441 | PyMODINIT_FUNC |
442 | PyInit__queue(void) |
443 | { |
444 | return PyModuleDef_Init(&queuemodule); |
445 | } |
446 | |