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1 | // Copyright 2016 Amanieu d'Antras |
2 | // | |
3 | // Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or | |
4 | // http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or | |
5 | // http://opensource.org/licenses/MIT>, at your option. This file may not be | |
6 | // copied, modified, or distributed except according to those terms. | |
7 | ||
8 | use crate::mutex::MutexGuard; | |
9 | use crate::raw_mutex::{RawMutex, TOKEN_HANDOFF, TOKEN_NORMAL}; | |
10 | use crate::{deadlock, util}; | |
11 | use core::{ | |
12 | fmt, ptr, | |
13 | sync::atomic::{AtomicPtr, Ordering}, | |
14 | }; | |
f035d41b | 15 | use instant::Instant; |
ba9703b0 XL |
16 | use lock_api::RawMutex as RawMutex_; |
17 | use parking_lot_core::{self, ParkResult, RequeueOp, UnparkResult, DEFAULT_PARK_TOKEN}; | |
f035d41b | 18 | use std::time::Duration; |
ba9703b0 XL |
19 | |
20 | /// A type indicating whether a timed wait on a condition variable returned | |
21 | /// due to a time out or not. | |
22 | #[derive(Debug, PartialEq, Eq, Copy, Clone)] | |
23 | pub struct WaitTimeoutResult(bool); | |
24 | ||
25 | impl WaitTimeoutResult { | |
26 | /// Returns whether the wait was known to have timed out. | |
27 | #[inline] | |
28 | pub fn timed_out(self) -> bool { | |
29 | self.0 | |
30 | } | |
31 | } | |
32 | ||
33 | /// A Condition Variable | |
34 | /// | |
35 | /// Condition variables represent the ability to block a thread such that it | |
36 | /// consumes no CPU time while waiting for an event to occur. Condition | |
37 | /// variables are typically associated with a boolean predicate (a condition) | |
38 | /// and a mutex. The predicate is always verified inside of the mutex before | |
39 | /// determining that thread must block. | |
40 | /// | |
41 | /// Note that this module places one additional restriction over the system | |
42 | /// condition variables: each condvar can be used with only one mutex at a | |
43 | /// time. Any attempt to use multiple mutexes on the same condition variable | |
44 | /// simultaneously will result in a runtime panic. However it is possible to | |
45 | /// switch to a different mutex if there are no threads currently waiting on | |
46 | /// the condition variable. | |
47 | /// | |
48 | /// # Differences from the standard library `Condvar` | |
49 | /// | |
50 | /// - No spurious wakeups: A wait will only return a non-timeout result if it | |
51 | /// was woken up by `notify_one` or `notify_all`. | |
52 | /// - `Condvar::notify_all` will only wake up a single thread, the rest are | |
53 | /// requeued to wait for the `Mutex` to be unlocked by the thread that was | |
54 | /// woken up. | |
55 | /// - Only requires 1 word of space, whereas the standard library boxes the | |
56 | /// `Condvar` due to platform limitations. | |
57 | /// - Can be statically constructed (requires the `const_fn` nightly feature). | |
58 | /// - Does not require any drop glue when dropped. | |
59 | /// - Inline fast path for the uncontended case. | |
60 | /// | |
61 | /// # Examples | |
62 | /// | |
63 | /// ``` | |
64 | /// use parking_lot::{Mutex, Condvar}; | |
65 | /// use std::sync::Arc; | |
66 | /// use std::thread; | |
67 | /// | |
68 | /// let pair = Arc::new((Mutex::new(false), Condvar::new())); | |
69 | /// let pair2 = pair.clone(); | |
70 | /// | |
71 | /// // Inside of our lock, spawn a new thread, and then wait for it to start | |
72 | /// thread::spawn(move|| { | |
73 | /// let &(ref lock, ref cvar) = &*pair2; | |
74 | /// let mut started = lock.lock(); | |
75 | /// *started = true; | |
76 | /// cvar.notify_one(); | |
77 | /// }); | |
78 | /// | |
79 | /// // wait for the thread to start up | |
80 | /// let &(ref lock, ref cvar) = &*pair; | |
81 | /// let mut started = lock.lock(); | |
82 | /// if !*started { | |
83 | /// cvar.wait(&mut started); | |
84 | /// } | |
85 | /// // Note that we used an if instead of a while loop above. This is only | |
86 | /// // possible because parking_lot's Condvar will never spuriously wake up. | |
87 | /// // This means that wait() will only return after notify_one or notify_all is | |
88 | /// // called. | |
89 | /// ``` | |
90 | pub struct Condvar { | |
91 | state: AtomicPtr<RawMutex>, | |
92 | } | |
93 | ||
94 | impl Condvar { | |
95 | /// Creates a new condition variable which is ready to be waited on and | |
96 | /// notified. | |
97 | #[inline] | |
98 | pub const fn new() -> Condvar { | |
99 | Condvar { | |
100 | state: AtomicPtr::new(ptr::null_mut()), | |
101 | } | |
102 | } | |
103 | ||
104 | /// Wakes up one blocked thread on this condvar. | |
105 | /// | |
106 | /// Returns whether a thread was woken up. | |
107 | /// | |
108 | /// If there is a blocked thread on this condition variable, then it will | |
109 | /// be woken up from its call to `wait` or `wait_timeout`. Calls to | |
110 | /// `notify_one` are not buffered in any way. | |
111 | /// | |
112 | /// To wake up all threads, see `notify_all()`. | |
113 | /// | |
114 | /// # Examples | |
115 | /// | |
116 | /// ``` | |
117 | /// use parking_lot::Condvar; | |
118 | /// | |
119 | /// let condvar = Condvar::new(); | |
120 | /// | |
121 | /// // do something with condvar, share it with other threads | |
122 | /// | |
123 | /// if !condvar.notify_one() { | |
124 | /// println!("Nobody was listening for this."); | |
125 | /// } | |
126 | /// ``` | |
127 | #[inline] | |
128 | pub fn notify_one(&self) -> bool { | |
129 | // Nothing to do if there are no waiting threads | |
130 | let state = self.state.load(Ordering::Relaxed); | |
131 | if state.is_null() { | |
132 | return false; | |
133 | } | |
134 | ||
135 | self.notify_one_slow(state) | |
136 | } | |
137 | ||
138 | #[cold] | |
139 | fn notify_one_slow(&self, mutex: *mut RawMutex) -> bool { | |
140 | unsafe { | |
141 | // Unpark one thread and requeue the rest onto the mutex | |
142 | let from = self as *const _ as usize; | |
143 | let to = mutex as usize; | |
144 | let validate = || { | |
145 | // Make sure that our atomic state still points to the same | |
146 | // mutex. If not then it means that all threads on the current | |
147 | // mutex were woken up and a new waiting thread switched to a | |
148 | // different mutex. In that case we can get away with doing | |
149 | // nothing. | |
150 | if self.state.load(Ordering::Relaxed) != mutex { | |
151 | return RequeueOp::Abort; | |
152 | } | |
153 | ||
154 | // Unpark one thread if the mutex is unlocked, otherwise just | |
155 | // requeue everything to the mutex. This is safe to do here | |
156 | // since unlocking the mutex when the parked bit is set requires | |
157 | // locking the queue. There is the possibility of a race if the | |
158 | // mutex gets locked after we check, but that doesn't matter in | |
159 | // this case. | |
160 | if (*mutex).mark_parked_if_locked() { | |
161 | RequeueOp::RequeueOne | |
162 | } else { | |
163 | RequeueOp::UnparkOne | |
164 | } | |
165 | }; | |
166 | let callback = |_op, result: UnparkResult| { | |
167 | // Clear our state if there are no more waiting threads | |
168 | if !result.have_more_threads { | |
169 | self.state.store(ptr::null_mut(), Ordering::Relaxed); | |
170 | } | |
171 | TOKEN_NORMAL | |
172 | }; | |
173 | let res = parking_lot_core::unpark_requeue(from, to, validate, callback); | |
174 | ||
175 | res.unparked_threads + res.requeued_threads != 0 | |
176 | } | |
177 | } | |
178 | ||
179 | /// Wakes up all blocked threads on this condvar. | |
180 | /// | |
181 | /// Returns the number of threads woken up. | |
182 | /// | |
183 | /// This method will ensure that any current waiters on the condition | |
184 | /// variable are awoken. Calls to `notify_all()` are not buffered in any | |
185 | /// way. | |
186 | /// | |
187 | /// To wake up only one thread, see `notify_one()`. | |
188 | #[inline] | |
189 | pub fn notify_all(&self) -> usize { | |
190 | // Nothing to do if there are no waiting threads | |
191 | let state = self.state.load(Ordering::Relaxed); | |
192 | if state.is_null() { | |
193 | return 0; | |
194 | } | |
195 | ||
196 | self.notify_all_slow(state) | |
197 | } | |
198 | ||
199 | #[cold] | |
200 | fn notify_all_slow(&self, mutex: *mut RawMutex) -> usize { | |
201 | unsafe { | |
202 | // Unpark one thread and requeue the rest onto the mutex | |
203 | let from = self as *const _ as usize; | |
204 | let to = mutex as usize; | |
205 | let validate = || { | |
206 | // Make sure that our atomic state still points to the same | |
207 | // mutex. If not then it means that all threads on the current | |
208 | // mutex were woken up and a new waiting thread switched to a | |
209 | // different mutex. In that case we can get away with doing | |
210 | // nothing. | |
211 | if self.state.load(Ordering::Relaxed) != mutex { | |
212 | return RequeueOp::Abort; | |
213 | } | |
214 | ||
215 | // Clear our state since we are going to unpark or requeue all | |
216 | // threads. | |
217 | self.state.store(ptr::null_mut(), Ordering::Relaxed); | |
218 | ||
219 | // Unpark one thread if the mutex is unlocked, otherwise just | |
220 | // requeue everything to the mutex. This is safe to do here | |
221 | // since unlocking the mutex when the parked bit is set requires | |
222 | // locking the queue. There is the possibility of a race if the | |
223 | // mutex gets locked after we check, but that doesn't matter in | |
224 | // this case. | |
225 | if (*mutex).mark_parked_if_locked() { | |
226 | RequeueOp::RequeueAll | |
227 | } else { | |
228 | RequeueOp::UnparkOneRequeueRest | |
229 | } | |
230 | }; | |
231 | let callback = |op, result: UnparkResult| { | |
232 | // If we requeued threads to the mutex, mark it as having | |
233 | // parked threads. The RequeueAll case is already handled above. | |
234 | if op == RequeueOp::UnparkOneRequeueRest && result.requeued_threads != 0 { | |
235 | (*mutex).mark_parked(); | |
236 | } | |
237 | TOKEN_NORMAL | |
238 | }; | |
239 | let res = parking_lot_core::unpark_requeue(from, to, validate, callback); | |
240 | ||
241 | res.unparked_threads + res.requeued_threads | |
242 | } | |
243 | } | |
244 | ||
245 | /// Blocks the current thread until this condition variable receives a | |
246 | /// notification. | |
247 | /// | |
248 | /// This function will atomically unlock the mutex specified (represented by | |
249 | /// `mutex_guard`) and block the current thread. This means that any calls | |
250 | /// to `notify_*()` which happen logically after the mutex is unlocked are | |
251 | /// candidates to wake this thread up. When this function call returns, the | |
252 | /// lock specified will have been re-acquired. | |
253 | /// | |
254 | /// # Panics | |
255 | /// | |
256 | /// This function will panic if another thread is waiting on the `Condvar` | |
257 | /// with a different `Mutex` object. | |
258 | #[inline] | |
259 | pub fn wait<T: ?Sized>(&self, mutex_guard: &mut MutexGuard<'_, T>) { | |
260 | self.wait_until_internal(unsafe { MutexGuard::mutex(mutex_guard).raw() }, None); | |
261 | } | |
262 | ||
263 | /// Waits on this condition variable for a notification, timing out after | |
264 | /// the specified time instant. | |
265 | /// | |
266 | /// The semantics of this function are equivalent to `wait()` except that | |
267 | /// the thread will be blocked roughly until `timeout` is reached. This | |
268 | /// method should not be used for precise timing due to anomalies such as | |
269 | /// preemption or platform differences that may not cause the maximum | |
270 | /// amount of time waited to be precisely `timeout`. | |
271 | /// | |
272 | /// Note that the best effort is made to ensure that the time waited is | |
273 | /// measured with a monotonic clock, and not affected by the changes made to | |
274 | /// the system time. | |
275 | /// | |
276 | /// The returned `WaitTimeoutResult` value indicates if the timeout is | |
277 | /// known to have elapsed. | |
278 | /// | |
279 | /// Like `wait`, the lock specified will be re-acquired when this function | |
280 | /// returns, regardless of whether the timeout elapsed or not. | |
281 | /// | |
282 | /// # Panics | |
283 | /// | |
284 | /// This function will panic if another thread is waiting on the `Condvar` | |
285 | /// with a different `Mutex` object. | |
286 | #[inline] | |
287 | pub fn wait_until<T: ?Sized>( | |
288 | &self, | |
289 | mutex_guard: &mut MutexGuard<'_, T>, | |
290 | timeout: Instant, | |
291 | ) -> WaitTimeoutResult { | |
292 | self.wait_until_internal( | |
293 | unsafe { MutexGuard::mutex(mutex_guard).raw() }, | |
294 | Some(timeout), | |
295 | ) | |
296 | } | |
297 | ||
298 | // This is a non-generic function to reduce the monomorphization cost of | |
299 | // using `wait_until`. | |
300 | fn wait_until_internal(&self, mutex: &RawMutex, timeout: Option<Instant>) -> WaitTimeoutResult { | |
301 | unsafe { | |
302 | let result; | |
303 | let mut bad_mutex = false; | |
304 | let mut requeued = false; | |
305 | { | |
306 | let addr = self as *const _ as usize; | |
307 | let lock_addr = mutex as *const _ as *mut _; | |
308 | let validate = || { | |
309 | // Ensure we don't use two different mutexes with the same | |
310 | // Condvar at the same time. This is done while locked to | |
311 | // avoid races with notify_one | |
312 | let state = self.state.load(Ordering::Relaxed); | |
313 | if state.is_null() { | |
314 | self.state.store(lock_addr, Ordering::Relaxed); | |
315 | } else if state != lock_addr { | |
316 | bad_mutex = true; | |
317 | return false; | |
318 | } | |
319 | true | |
320 | }; | |
321 | let before_sleep = || { | |
322 | // Unlock the mutex before sleeping... | |
323 | mutex.unlock(); | |
324 | }; | |
325 | let timed_out = |k, was_last_thread| { | |
326 | // If we were requeued to a mutex, then we did not time out. | |
327 | // We'll just park ourselves on the mutex again when we try | |
328 | // to lock it later. | |
329 | requeued = k != addr; | |
330 | ||
331 | // If we were the last thread on the queue then we need to | |
332 | // clear our state. This is normally done by the | |
333 | // notify_{one,all} functions when not timing out. | |
334 | if !requeued && was_last_thread { | |
335 | self.state.store(ptr::null_mut(), Ordering::Relaxed); | |
336 | } | |
337 | }; | |
338 | result = parking_lot_core::park( | |
339 | addr, | |
340 | validate, | |
341 | before_sleep, | |
342 | timed_out, | |
343 | DEFAULT_PARK_TOKEN, | |
344 | timeout, | |
345 | ); | |
346 | } | |
347 | ||
348 | // Panic if we tried to use multiple mutexes with a Condvar. Note | |
349 | // that at this point the MutexGuard is still locked. It will be | |
350 | // unlocked by the unwinding logic. | |
351 | if bad_mutex { | |
352 | panic!("attempted to use a condition variable with more than one mutex"); | |
353 | } | |
354 | ||
355 | // ... and re-lock it once we are done sleeping | |
356 | if result == ParkResult::Unparked(TOKEN_HANDOFF) { | |
357 | deadlock::acquire_resource(mutex as *const _ as usize); | |
358 | } else { | |
359 | mutex.lock(); | |
360 | } | |
361 | ||
362 | WaitTimeoutResult(!(result.is_unparked() || requeued)) | |
363 | } | |
364 | } | |
365 | ||
366 | /// Waits on this condition variable for a notification, timing out after a | |
367 | /// specified duration. | |
368 | /// | |
369 | /// The semantics of this function are equivalent to `wait()` except that | |
370 | /// the thread will be blocked for roughly no longer than `timeout`. This | |
371 | /// method should not be used for precise timing due to anomalies such as | |
372 | /// preemption or platform differences that may not cause the maximum | |
373 | /// amount of time waited to be precisely `timeout`. | |
374 | /// | |
375 | /// Note that the best effort is made to ensure that the time waited is | |
376 | /// measured with a monotonic clock, and not affected by the changes made to | |
377 | /// the system time. | |
378 | /// | |
379 | /// The returned `WaitTimeoutResult` value indicates if the timeout is | |
380 | /// known to have elapsed. | |
381 | /// | |
382 | /// Like `wait`, the lock specified will be re-acquired when this function | |
383 | /// returns, regardless of whether the timeout elapsed or not. | |
384 | /// | |
385 | /// # Panics | |
386 | /// | |
387 | /// Panics if the given `timeout` is so large that it can't be added to the current time. | |
388 | /// This panic is not possible if the crate is built with the `nightly` feature, then a too | |
389 | /// large `timeout` becomes equivalent to just calling `wait`. | |
390 | #[inline] | |
391 | pub fn wait_for<T: ?Sized>( | |
392 | &self, | |
393 | mutex_guard: &mut MutexGuard<'_, T>, | |
394 | timeout: Duration, | |
395 | ) -> WaitTimeoutResult { | |
396 | let deadline = util::to_deadline(timeout); | |
397 | self.wait_until_internal(unsafe { MutexGuard::mutex(mutex_guard).raw() }, deadline) | |
398 | } | |
399 | } | |
400 | ||
401 | impl Default for Condvar { | |
402 | #[inline] | |
403 | fn default() -> Condvar { | |
404 | Condvar::new() | |
405 | } | |
406 | } | |
407 | ||
408 | impl fmt::Debug for Condvar { | |
409 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
410 | f.pad("Condvar { .. }") | |
411 | } | |
412 | } | |
413 | ||
414 | #[cfg(test)] | |
415 | mod tests { | |
416 | use crate::{Condvar, Mutex, MutexGuard}; | |
f035d41b | 417 | use instant::Instant; |
ba9703b0 XL |
418 | use std::sync::mpsc::channel; |
419 | use std::sync::Arc; | |
420 | use std::thread; | |
f035d41b | 421 | use std::time::Duration; |
ba9703b0 XL |
422 | |
423 | #[test] | |
424 | fn smoke() { | |
425 | let c = Condvar::new(); | |
426 | c.notify_one(); | |
427 | c.notify_all(); | |
428 | } | |
429 | ||
430 | #[test] | |
431 | fn notify_one() { | |
432 | let m = Arc::new(Mutex::new(())); | |
433 | let m2 = m.clone(); | |
434 | let c = Arc::new(Condvar::new()); | |
435 | let c2 = c.clone(); | |
436 | ||
437 | let mut g = m.lock(); | |
438 | let _t = thread::spawn(move || { | |
439 | let _g = m2.lock(); | |
440 | c2.notify_one(); | |
441 | }); | |
442 | c.wait(&mut g); | |
443 | } | |
444 | ||
445 | #[test] | |
446 | fn notify_all() { | |
447 | const N: usize = 10; | |
448 | ||
449 | let data = Arc::new((Mutex::new(0), Condvar::new())); | |
450 | let (tx, rx) = channel(); | |
451 | for _ in 0..N { | |
452 | let data = data.clone(); | |
453 | let tx = tx.clone(); | |
454 | thread::spawn(move || { | |
455 | let &(ref lock, ref cond) = &*data; | |
456 | let mut cnt = lock.lock(); | |
457 | *cnt += 1; | |
458 | if *cnt == N { | |
459 | tx.send(()).unwrap(); | |
460 | } | |
461 | while *cnt != 0 { | |
462 | cond.wait(&mut cnt); | |
463 | } | |
464 | tx.send(()).unwrap(); | |
465 | }); | |
466 | } | |
467 | drop(tx); | |
468 | ||
469 | let &(ref lock, ref cond) = &*data; | |
470 | rx.recv().unwrap(); | |
471 | let mut cnt = lock.lock(); | |
472 | *cnt = 0; | |
473 | cond.notify_all(); | |
474 | drop(cnt); | |
475 | ||
476 | for _ in 0..N { | |
477 | rx.recv().unwrap(); | |
478 | } | |
479 | } | |
480 | ||
481 | #[test] | |
482 | fn notify_one_return_true() { | |
483 | let m = Arc::new(Mutex::new(())); | |
484 | let m2 = m.clone(); | |
485 | let c = Arc::new(Condvar::new()); | |
486 | let c2 = c.clone(); | |
487 | ||
488 | let mut g = m.lock(); | |
489 | let _t = thread::spawn(move || { | |
490 | let _g = m2.lock(); | |
491 | assert!(c2.notify_one()); | |
492 | }); | |
493 | c.wait(&mut g); | |
494 | } | |
495 | ||
496 | #[test] | |
497 | fn notify_one_return_false() { | |
498 | let m = Arc::new(Mutex::new(())); | |
499 | let c = Arc::new(Condvar::new()); | |
500 | ||
501 | let _t = thread::spawn(move || { | |
502 | let _g = m.lock(); | |
503 | assert!(!c.notify_one()); | |
504 | }); | |
505 | } | |
506 | ||
507 | #[test] | |
508 | fn notify_all_return() { | |
509 | const N: usize = 10; | |
510 | ||
511 | let data = Arc::new((Mutex::new(0), Condvar::new())); | |
512 | let (tx, rx) = channel(); | |
513 | for _ in 0..N { | |
514 | let data = data.clone(); | |
515 | let tx = tx.clone(); | |
516 | thread::spawn(move || { | |
517 | let &(ref lock, ref cond) = &*data; | |
518 | let mut cnt = lock.lock(); | |
519 | *cnt += 1; | |
520 | if *cnt == N { | |
521 | tx.send(()).unwrap(); | |
522 | } | |
523 | while *cnt != 0 { | |
524 | cond.wait(&mut cnt); | |
525 | } | |
526 | tx.send(()).unwrap(); | |
527 | }); | |
528 | } | |
529 | drop(tx); | |
530 | ||
531 | let &(ref lock, ref cond) = &*data; | |
532 | rx.recv().unwrap(); | |
533 | let mut cnt = lock.lock(); | |
534 | *cnt = 0; | |
535 | assert_eq!(cond.notify_all(), N); | |
536 | drop(cnt); | |
537 | ||
538 | for _ in 0..N { | |
539 | rx.recv().unwrap(); | |
540 | } | |
541 | ||
542 | assert_eq!(cond.notify_all(), 0); | |
543 | } | |
544 | ||
545 | #[test] | |
546 | fn wait_for() { | |
547 | let m = Arc::new(Mutex::new(())); | |
548 | let m2 = m.clone(); | |
549 | let c = Arc::new(Condvar::new()); | |
550 | let c2 = c.clone(); | |
551 | ||
552 | let mut g = m.lock(); | |
553 | let no_timeout = c.wait_for(&mut g, Duration::from_millis(1)); | |
554 | assert!(no_timeout.timed_out()); | |
555 | ||
556 | let _t = thread::spawn(move || { | |
557 | let _g = m2.lock(); | |
558 | c2.notify_one(); | |
559 | }); | |
560 | // Non-nightly panics on too large timeouts. Nightly treats it as indefinite wait. | |
561 | let very_long_timeout = if cfg!(feature = "nightly") { | |
562 | Duration::from_secs(u64::max_value()) | |
563 | } else { | |
564 | Duration::from_millis(u32::max_value() as u64) | |
565 | }; | |
566 | ||
567 | let timeout_res = c.wait_for(&mut g, very_long_timeout); | |
568 | assert!(!timeout_res.timed_out()); | |
569 | ||
570 | drop(g); | |
571 | } | |
572 | ||
573 | #[test] | |
574 | fn wait_until() { | |
575 | let m = Arc::new(Mutex::new(())); | |
576 | let m2 = m.clone(); | |
577 | let c = Arc::new(Condvar::new()); | |
578 | let c2 = c.clone(); | |
579 | ||
580 | let mut g = m.lock(); | |
581 | let no_timeout = c.wait_until(&mut g, Instant::now() + Duration::from_millis(1)); | |
582 | assert!(no_timeout.timed_out()); | |
583 | let _t = thread::spawn(move || { | |
584 | let _g = m2.lock(); | |
585 | c2.notify_one(); | |
586 | }); | |
587 | let timeout_res = c.wait_until( | |
588 | &mut g, | |
589 | Instant::now() + Duration::from_millis(u32::max_value() as u64), | |
590 | ); | |
591 | assert!(!timeout_res.timed_out()); | |
592 | drop(g); | |
593 | } | |
594 | ||
595 | #[test] | |
596 | #[should_panic] | |
597 | fn two_mutexes() { | |
598 | let m = Arc::new(Mutex::new(())); | |
599 | let m2 = m.clone(); | |
600 | let m3 = Arc::new(Mutex::new(())); | |
601 | let c = Arc::new(Condvar::new()); | |
602 | let c2 = c.clone(); | |
603 | ||
604 | // Make sure we don't leave the child thread dangling | |
605 | struct PanicGuard<'a>(&'a Condvar); | |
606 | impl<'a> Drop for PanicGuard<'a> { | |
607 | fn drop(&mut self) { | |
608 | self.0.notify_one(); | |
609 | } | |
610 | } | |
611 | ||
612 | let (tx, rx) = channel(); | |
613 | let g = m.lock(); | |
614 | let _t = thread::spawn(move || { | |
615 | let mut g = m2.lock(); | |
616 | tx.send(()).unwrap(); | |
617 | c2.wait(&mut g); | |
618 | }); | |
619 | drop(g); | |
620 | rx.recv().unwrap(); | |
621 | let _g = m.lock(); | |
622 | let _guard = PanicGuard(&*c); | |
623 | c.wait(&mut m3.lock()); | |
624 | } | |
625 | ||
626 | #[test] | |
627 | fn two_mutexes_disjoint() { | |
628 | let m = Arc::new(Mutex::new(())); | |
629 | let m2 = m.clone(); | |
630 | let m3 = Arc::new(Mutex::new(())); | |
631 | let c = Arc::new(Condvar::new()); | |
632 | let c2 = c.clone(); | |
633 | ||
634 | let mut g = m.lock(); | |
635 | let _t = thread::spawn(move || { | |
636 | let _g = m2.lock(); | |
637 | c2.notify_one(); | |
638 | }); | |
639 | c.wait(&mut g); | |
640 | drop(g); | |
641 | ||
642 | let _ = c.wait_for(&mut m3.lock(), Duration::from_millis(1)); | |
643 | } | |
644 | ||
645 | #[test] | |
646 | fn test_debug_condvar() { | |
647 | let c = Condvar::new(); | |
648 | assert_eq!(format!("{:?}", c), "Condvar { .. }"); | |
649 | } | |
650 | ||
651 | #[test] | |
652 | fn test_condvar_requeue() { | |
653 | let m = Arc::new(Mutex::new(())); | |
654 | let m2 = m.clone(); | |
655 | let c = Arc::new(Condvar::new()); | |
656 | let c2 = c.clone(); | |
657 | let t = thread::spawn(move || { | |
658 | let mut g = m2.lock(); | |
659 | c2.wait(&mut g); | |
660 | }); | |
661 | ||
662 | let mut g = m.lock(); | |
663 | while !c.notify_one() { | |
664 | // Wait for the thread to get into wait() | |
665 | MutexGuard::bump(&mut g); | |
5869c6ff XL |
666 | // Yield, so the other thread gets a chance to do something. |
667 | // (At least Miri needs this, because it doesn't preempt threads.) | |
668 | thread::yield_now(); | |
ba9703b0 XL |
669 | } |
670 | // The thread should have been requeued to the mutex, which we wake up now. | |
671 | drop(g); | |
672 | t.join().unwrap(); | |
673 | } | |
674 | ||
675 | #[test] | |
676 | fn test_issue_129() { | |
677 | let locks = Arc::new((Mutex::new(()), Condvar::new())); | |
678 | ||
679 | let (tx, rx) = channel(); | |
680 | for _ in 0..4 { | |
681 | let locks = locks.clone(); | |
682 | let tx = tx.clone(); | |
683 | thread::spawn(move || { | |
684 | let mut guard = locks.0.lock(); | |
685 | locks.1.wait(&mut guard); | |
686 | locks.1.wait_for(&mut guard, Duration::from_millis(1)); | |
687 | locks.1.notify_one(); | |
688 | tx.send(()).unwrap(); | |
689 | }); | |
690 | } | |
691 | ||
692 | thread::sleep(Duration::from_millis(100)); | |
693 | locks.1.notify_one(); | |
694 | ||
695 | for _ in 0..4 { | |
696 | assert_eq!(rx.recv_timeout(Duration::from_millis(500)), Ok(())); | |
697 | } | |
698 | } | |
699 | } | |
700 | ||
701 | /// This module contains an integration test that is heavily inspired from WebKit's own integration | |
702 | /// tests for it's own Condvar. | |
703 | #[cfg(test)] | |
704 | mod webkit_queue_test { | |
705 | use crate::{Condvar, Mutex, MutexGuard}; | |
706 | use std::{collections::VecDeque, sync::Arc, thread, time::Duration}; | |
707 | ||
708 | #[derive(Clone, Copy)] | |
709 | enum Timeout { | |
710 | Bounded(Duration), | |
711 | Forever, | |
712 | } | |
713 | ||
714 | #[derive(Clone, Copy)] | |
715 | enum NotifyStyle { | |
716 | One, | |
717 | All, | |
718 | } | |
719 | ||
720 | struct Queue { | |
721 | items: VecDeque<usize>, | |
722 | should_continue: bool, | |
723 | } | |
724 | ||
725 | impl Queue { | |
726 | fn new() -> Self { | |
727 | Self { | |
728 | items: VecDeque::new(), | |
729 | should_continue: true, | |
730 | } | |
731 | } | |
732 | } | |
733 | ||
734 | fn wait<T: ?Sized>( | |
735 | condition: &Condvar, | |
736 | lock: &mut MutexGuard<'_, T>, | |
737 | predicate: impl Fn(&mut MutexGuard<'_, T>) -> bool, | |
738 | timeout: &Timeout, | |
739 | ) { | |
740 | while !predicate(lock) { | |
741 | match timeout { | |
742 | Timeout::Forever => condition.wait(lock), | |
743 | Timeout::Bounded(bound) => { | |
744 | condition.wait_for(lock, *bound); | |
745 | } | |
746 | } | |
747 | } | |
748 | } | |
749 | ||
750 | fn notify(style: NotifyStyle, condition: &Condvar, should_notify: bool) { | |
751 | match style { | |
752 | NotifyStyle::One => { | |
753 | condition.notify_one(); | |
754 | } | |
755 | NotifyStyle::All => { | |
756 | if should_notify { | |
757 | condition.notify_all(); | |
758 | } | |
759 | } | |
760 | } | |
761 | } | |
762 | ||
763 | fn run_queue_test( | |
764 | num_producers: usize, | |
765 | num_consumers: usize, | |
766 | max_queue_size: usize, | |
767 | messages_per_producer: usize, | |
768 | notify_style: NotifyStyle, | |
769 | timeout: Timeout, | |
770 | delay: Duration, | |
771 | ) { | |
772 | let input_queue = Arc::new(Mutex::new(Queue::new())); | |
773 | let empty_condition = Arc::new(Condvar::new()); | |
774 | let full_condition = Arc::new(Condvar::new()); | |
775 | ||
776 | let output_vec = Arc::new(Mutex::new(vec![])); | |
777 | ||
778 | let consumers = (0..num_consumers) | |
779 | .map(|_| { | |
780 | consumer_thread( | |
781 | input_queue.clone(), | |
782 | empty_condition.clone(), | |
783 | full_condition.clone(), | |
784 | timeout, | |
785 | notify_style, | |
786 | output_vec.clone(), | |
787 | max_queue_size, | |
788 | ) | |
789 | }) | |
790 | .collect::<Vec<_>>(); | |
791 | let producers = (0..num_producers) | |
792 | .map(|_| { | |
793 | producer_thread( | |
794 | messages_per_producer, | |
795 | input_queue.clone(), | |
796 | empty_condition.clone(), | |
797 | full_condition.clone(), | |
798 | timeout, | |
799 | notify_style, | |
800 | max_queue_size, | |
801 | ) | |
802 | }) | |
803 | .collect::<Vec<_>>(); | |
804 | ||
805 | thread::sleep(delay); | |
806 | ||
807 | for producer in producers.into_iter() { | |
808 | producer.join().expect("Producer thread panicked"); | |
809 | } | |
810 | ||
811 | { | |
812 | let mut input_queue = input_queue.lock(); | |
813 | input_queue.should_continue = false; | |
814 | } | |
815 | empty_condition.notify_all(); | |
816 | ||
817 | for consumer in consumers.into_iter() { | |
818 | consumer.join().expect("Consumer thread panicked"); | |
819 | } | |
820 | ||
821 | let mut output_vec = output_vec.lock(); | |
822 | assert_eq!(output_vec.len(), num_producers * messages_per_producer); | |
823 | output_vec.sort(); | |
824 | for msg_idx in 0..messages_per_producer { | |
825 | for producer_idx in 0..num_producers { | |
826 | assert_eq!(msg_idx, output_vec[msg_idx * num_producers + producer_idx]); | |
827 | } | |
828 | } | |
829 | } | |
830 | ||
831 | fn consumer_thread( | |
832 | input_queue: Arc<Mutex<Queue>>, | |
833 | empty_condition: Arc<Condvar>, | |
834 | full_condition: Arc<Condvar>, | |
835 | timeout: Timeout, | |
836 | notify_style: NotifyStyle, | |
837 | output_queue: Arc<Mutex<Vec<usize>>>, | |
838 | max_queue_size: usize, | |
839 | ) -> thread::JoinHandle<()> { | |
840 | thread::spawn(move || loop { | |
841 | let (should_notify, result) = { | |
842 | let mut queue = input_queue.lock(); | |
843 | wait( | |
844 | &*empty_condition, | |
845 | &mut queue, | |
846 | |state| -> bool { !state.items.is_empty() || !state.should_continue }, | |
847 | &timeout, | |
848 | ); | |
849 | if queue.items.is_empty() && !queue.should_continue { | |
850 | return; | |
851 | } | |
852 | let should_notify = queue.items.len() == max_queue_size; | |
853 | let result = queue.items.pop_front(); | |
854 | std::mem::drop(queue); | |
855 | (should_notify, result) | |
856 | }; | |
857 | notify(notify_style, &*full_condition, should_notify); | |
858 | ||
859 | if let Some(result) = result { | |
860 | output_queue.lock().push(result); | |
861 | } | |
862 | }) | |
863 | } | |
864 | ||
865 | fn producer_thread( | |
866 | num_messages: usize, | |
867 | queue: Arc<Mutex<Queue>>, | |
868 | empty_condition: Arc<Condvar>, | |
869 | full_condition: Arc<Condvar>, | |
870 | timeout: Timeout, | |
871 | notify_style: NotifyStyle, | |
872 | max_queue_size: usize, | |
873 | ) -> thread::JoinHandle<()> { | |
874 | thread::spawn(move || { | |
875 | for message in 0..num_messages { | |
876 | let should_notify = { | |
877 | let mut queue = queue.lock(); | |
878 | wait( | |
879 | &*full_condition, | |
880 | &mut queue, | |
881 | |state| state.items.len() < max_queue_size, | |
882 | &timeout, | |
883 | ); | |
884 | let should_notify = queue.items.is_empty(); | |
885 | queue.items.push_back(message); | |
886 | std::mem::drop(queue); | |
887 | should_notify | |
888 | }; | |
889 | notify(notify_style, &*empty_condition, should_notify); | |
890 | } | |
891 | }) | |
892 | } | |
893 | ||
894 | macro_rules! run_queue_tests { | |
895 | ( $( $name:ident( | |
896 | num_producers: $num_producers:expr, | |
897 | num_consumers: $num_consumers:expr, | |
898 | max_queue_size: $max_queue_size:expr, | |
899 | messages_per_producer: $messages_per_producer:expr, | |
900 | notification_style: $notification_style:expr, | |
901 | timeout: $timeout:expr, | |
902 | delay_seconds: $delay_seconds:expr); | |
903 | )* ) => { | |
904 | $(#[test] | |
905 | fn $name() { | |
906 | let delay = Duration::from_secs($delay_seconds); | |
907 | run_queue_test( | |
908 | $num_producers, | |
909 | $num_consumers, | |
910 | $max_queue_size, | |
911 | $messages_per_producer, | |
912 | $notification_style, | |
913 | $timeout, | |
914 | delay, | |
915 | ); | |
916 | })* | |
917 | }; | |
918 | } | |
919 | ||
920 | run_queue_tests! { | |
921 | sanity_check_queue( | |
922 | num_producers: 1, | |
923 | num_consumers: 1, | |
924 | max_queue_size: 1, | |
925 | messages_per_producer: 100_000, | |
926 | notification_style: NotifyStyle::All, | |
927 | timeout: Timeout::Bounded(Duration::from_secs(1)), | |
928 | delay_seconds: 0 | |
929 | ); | |
930 | sanity_check_queue_timeout( | |
931 | num_producers: 1, | |
932 | num_consumers: 1, | |
933 | max_queue_size: 1, | |
934 | messages_per_producer: 100_000, | |
935 | notification_style: NotifyStyle::All, | |
936 | timeout: Timeout::Forever, | |
937 | delay_seconds: 0 | |
938 | ); | |
939 | new_test_without_timeout_5( | |
940 | num_producers: 1, | |
941 | num_consumers: 5, | |
942 | max_queue_size: 1, | |
943 | messages_per_producer: 100_000, | |
944 | notification_style: NotifyStyle::All, | |
945 | timeout: Timeout::Forever, | |
946 | delay_seconds: 0 | |
947 | ); | |
948 | one_producer_one_consumer_one_slot( | |
949 | num_producers: 1, | |
950 | num_consumers: 1, | |
951 | max_queue_size: 1, | |
952 | messages_per_producer: 100_000, | |
953 | notification_style: NotifyStyle::All, | |
954 | timeout: Timeout::Forever, | |
955 | delay_seconds: 0 | |
956 | ); | |
957 | one_producer_one_consumer_one_slot_timeout( | |
958 | num_producers: 1, | |
959 | num_consumers: 1, | |
960 | max_queue_size: 1, | |
961 | messages_per_producer: 100_000, | |
962 | notification_style: NotifyStyle::All, | |
963 | timeout: Timeout::Forever, | |
964 | delay_seconds: 1 | |
965 | ); | |
966 | one_producer_one_consumer_hundred_slots( | |
967 | num_producers: 1, | |
968 | num_consumers: 1, | |
969 | max_queue_size: 100, | |
970 | messages_per_producer: 1_000_000, | |
971 | notification_style: NotifyStyle::All, | |
972 | timeout: Timeout::Forever, | |
973 | delay_seconds: 0 | |
974 | ); | |
975 | ten_producers_one_consumer_one_slot( | |
976 | num_producers: 10, | |
977 | num_consumers: 1, | |
978 | max_queue_size: 1, | |
979 | messages_per_producer: 10000, | |
980 | notification_style: NotifyStyle::All, | |
981 | timeout: Timeout::Forever, | |
982 | delay_seconds: 0 | |
983 | ); | |
984 | ten_producers_one_consumer_hundred_slots_notify_all( | |
985 | num_producers: 10, | |
986 | num_consumers: 1, | |
987 | max_queue_size: 100, | |
988 | messages_per_producer: 10000, | |
989 | notification_style: NotifyStyle::All, | |
990 | timeout: Timeout::Forever, | |
991 | delay_seconds: 0 | |
992 | ); | |
993 | ten_producers_one_consumer_hundred_slots_notify_one( | |
994 | num_producers: 10, | |
995 | num_consumers: 1, | |
996 | max_queue_size: 100, | |
997 | messages_per_producer: 10000, | |
998 | notification_style: NotifyStyle::One, | |
999 | timeout: Timeout::Forever, | |
1000 | delay_seconds: 0 | |
1001 | ); | |
1002 | one_producer_ten_consumers_one_slot( | |
1003 | num_producers: 1, | |
1004 | num_consumers: 10, | |
1005 | max_queue_size: 1, | |
1006 | messages_per_producer: 10000, | |
1007 | notification_style: NotifyStyle::All, | |
1008 | timeout: Timeout::Forever, | |
1009 | delay_seconds: 0 | |
1010 | ); | |
1011 | one_producer_ten_consumers_hundred_slots_notify_all( | |
1012 | num_producers: 1, | |
1013 | num_consumers: 10, | |
1014 | max_queue_size: 100, | |
1015 | messages_per_producer: 100_000, | |
1016 | notification_style: NotifyStyle::All, | |
1017 | timeout: Timeout::Forever, | |
1018 | delay_seconds: 0 | |
1019 | ); | |
1020 | one_producer_ten_consumers_hundred_slots_notify_one( | |
1021 | num_producers: 1, | |
1022 | num_consumers: 10, | |
1023 | max_queue_size: 100, | |
1024 | messages_per_producer: 100_000, | |
1025 | notification_style: NotifyStyle::One, | |
1026 | timeout: Timeout::Forever, | |
1027 | delay_seconds: 0 | |
1028 | ); | |
1029 | ten_producers_ten_consumers_one_slot( | |
1030 | num_producers: 10, | |
1031 | num_consumers: 10, | |
1032 | max_queue_size: 1, | |
1033 | messages_per_producer: 50000, | |
1034 | notification_style: NotifyStyle::All, | |
1035 | timeout: Timeout::Forever, | |
1036 | delay_seconds: 0 | |
1037 | ); | |
1038 | ten_producers_ten_consumers_hundred_slots_notify_all( | |
1039 | num_producers: 10, | |
1040 | num_consumers: 10, | |
1041 | max_queue_size: 100, | |
1042 | messages_per_producer: 50000, | |
1043 | notification_style: NotifyStyle::All, | |
1044 | timeout: Timeout::Forever, | |
1045 | delay_seconds: 0 | |
1046 | ); | |
1047 | ten_producers_ten_consumers_hundred_slots_notify_one( | |
1048 | num_producers: 10, | |
1049 | num_consumers: 10, | |
1050 | max_queue_size: 100, | |
1051 | messages_per_producer: 50000, | |
1052 | notification_style: NotifyStyle::One, | |
1053 | timeout: Timeout::Forever, | |
1054 | delay_seconds: 0 | |
1055 | ); | |
1056 | } | |
1057 | } |