1#![warn(rust_2018_idioms)]
2#![cfg(feature = "full")]
3
4use std::mem;
5use std::ops::Drop;
6use std::sync::atomic::{AtomicU32, Ordering};
7use std::time::Duration;
8use tokio::runtime;
9use tokio::sync::OnceCell;
10use tokio::sync::SetError;
11use tokio::time;
12
13#[test]
14fn drop_cell() {
15 static NUM_DROPS: AtomicU32 = AtomicU32::new(0);
16
17 struct Foo {}
18
19 let fooer = Foo {};
20
21 impl Drop for Foo {
22 fn drop(&mut self) {
23 NUM_DROPS.fetch_add(1, Ordering::Release);
24 }
25 }
26
27 {
28 let once_cell = OnceCell::new();
29 let prev = once_cell.set(fooer);
30 assert!(prev.is_ok())
31 }
32 assert!(NUM_DROPS.load(Ordering::Acquire) == 1);
33}
34
35#[test]
36fn drop_cell_new_with() {
37 static NUM_DROPS: AtomicU32 = AtomicU32::new(0);
38
39 struct Foo {}
40
41 let fooer = Foo {};
42
43 impl Drop for Foo {
44 fn drop(&mut self) {
45 NUM_DROPS.fetch_add(1, Ordering::Release);
46 }
47 }
48
49 {
50 let once_cell = OnceCell::new_with(Some(fooer));
51 assert!(once_cell.initialized());
52 }
53 assert!(NUM_DROPS.load(Ordering::Acquire) == 1);
54}
55
56#[test]
57fn drop_into_inner() {
58 static NUM_DROPS: AtomicU32 = AtomicU32::new(0);
59
60 struct Foo {}
61
62 let fooer = Foo {};
63
64 impl Drop for Foo {
65 fn drop(&mut self) {
66 NUM_DROPS.fetch_add(1, Ordering::Release);
67 }
68 }
69
70 let once_cell = OnceCell::new();
71 assert!(once_cell.set(fooer).is_ok());
72 let fooer = once_cell.into_inner();
73 let count = NUM_DROPS.load(Ordering::Acquire);
74 assert!(count == 0);
75 drop(fooer);
76 let count = NUM_DROPS.load(Ordering::Acquire);
77 assert!(count == 1);
78}
79
80#[test]
81fn drop_into_inner_new_with() {
82 static NUM_DROPS: AtomicU32 = AtomicU32::new(0);
83
84 struct Foo {}
85
86 let fooer = Foo {};
87
88 impl Drop for Foo {
89 fn drop(&mut self) {
90 NUM_DROPS.fetch_add(1, Ordering::Release);
91 }
92 }
93
94 let once_cell = OnceCell::new_with(Some(fooer));
95 let fooer = once_cell.into_inner();
96 let count = NUM_DROPS.load(Ordering::Acquire);
97 assert!(count == 0);
98 mem::drop(fooer);
99 let count = NUM_DROPS.load(Ordering::Acquire);
100 assert!(count == 1);
101}
102
103#[test]
104fn from() {
105 let cell = OnceCell::from(2);
106 assert_eq!(*cell.get().unwrap(), 2);
107}
108
109async fn func1() -> u32 {
110 5
111}
112
113async fn func2() -> u32 {
114 time::sleep(Duration::from_millis(1)).await;
115 10
116}
117
118async fn func_err() -> Result<u32, ()> {
119 Err(())
120}
121
122async fn func_ok() -> Result<u32, ()> {
123 Ok(10)
124}
125
126async fn func_panic() -> u32 {
127 time::sleep(Duration::from_millis(1)).await;
128 panic!();
129}
130
131async fn sleep_and_set() -> u32 {
132 // Simulate sleep by pausing time and waiting for another thread to
133 // resume clock when calling `set`, then finding the cell being initialized
134 // by this call
135 time::sleep(Duration::from_millis(2)).await;
136 5
137}
138
139async fn advance_time_and_set(cell: &'static OnceCell<u32>, v: u32) -> Result<(), SetError<u32>> {
140 time::advance(Duration::from_millis(1)).await;
141 cell.set(v)
142}
143
144#[test]
145fn get_or_init() {
146 let rt = runtime::Builder::new_current_thread()
147 .enable_time()
148 .start_paused(true)
149 .build()
150 .unwrap();
151
152 static ONCE: OnceCell<u32> = OnceCell::const_new();
153
154 rt.block_on(async {
155 let handle1 = rt.spawn(async { ONCE.get_or_init(func1).await });
156 let handle2 = rt.spawn(async { ONCE.get_or_init(func2).await });
157
158 time::advance(Duration::from_millis(1)).await;
159 time::resume();
160
161 let result1 = handle1.await.unwrap();
162 let result2 = handle2.await.unwrap();
163
164 assert_eq!(*result1, 5);
165 assert_eq!(*result2, 5);
166 });
167}
168
169#[test]
170fn get_or_init_panic() {
171 let rt = runtime::Builder::new_current_thread()
172 .enable_time()
173 .build()
174 .unwrap();
175
176 static ONCE: OnceCell<u32> = OnceCell::const_new();
177
178 rt.block_on(async {
179 time::pause();
180
181 let handle1 = rt.spawn(async { ONCE.get_or_init(func1).await });
182 let handle2 = rt.spawn(async { ONCE.get_or_init(func_panic).await });
183
184 time::advance(Duration::from_millis(1)).await;
185
186 let result1 = handle1.await.unwrap();
187 let result2 = handle2.await.unwrap();
188
189 assert_eq!(*result1, 5);
190 assert_eq!(*result2, 5);
191 });
192}
193
194#[test]
195fn set_and_get() {
196 let rt = runtime::Builder::new_current_thread()
197 .enable_time()
198 .build()
199 .unwrap();
200
201 static ONCE: OnceCell<u32> = OnceCell::const_new();
202
203 rt.block_on(async {
204 let _ = rt.spawn(async { ONCE.set(5) }).await;
205 let value = ONCE.get().unwrap();
206 assert_eq!(*value, 5);
207 });
208}
209
210#[test]
211fn get_uninit() {
212 static ONCE: OnceCell<u32> = OnceCell::const_new();
213 let uninit = ONCE.get();
214 assert!(uninit.is_none());
215}
216
217#[test]
218fn set_twice() {
219 static ONCE: OnceCell<u32> = OnceCell::const_new();
220
221 let first = ONCE.set(5);
222 assert_eq!(first, Ok(()));
223 let second = ONCE.set(6);
224 assert!(second.err().unwrap().is_already_init_err());
225}
226
227#[test]
228fn set_while_initializing() {
229 let rt = runtime::Builder::new_current_thread()
230 .enable_time()
231 .build()
232 .unwrap();
233
234 static ONCE: OnceCell<u32> = OnceCell::const_new();
235
236 rt.block_on(async {
237 time::pause();
238
239 let handle1 = rt.spawn(async { ONCE.get_or_init(sleep_and_set).await });
240 let handle2 = rt.spawn(async { advance_time_and_set(&ONCE, 10).await });
241
242 time::advance(Duration::from_millis(2)).await;
243
244 let result1 = handle1.await.unwrap();
245 let result2 = handle2.await.unwrap();
246
247 assert_eq!(*result1, 5);
248 assert!(result2.err().unwrap().is_initializing_err());
249 });
250}
251
252#[test]
253fn get_or_try_init() {
254 let rt = runtime::Builder::new_current_thread()
255 .enable_time()
256 .start_paused(true)
257 .build()
258 .unwrap();
259
260 static ONCE: OnceCell<u32> = OnceCell::const_new();
261
262 rt.block_on(async {
263 let handle1 = rt.spawn(async { ONCE.get_or_try_init(func_err).await });
264 let handle2 = rt.spawn(async { ONCE.get_or_try_init(func_ok).await });
265
266 time::advance(Duration::from_millis(1)).await;
267 time::resume();
268
269 let result1 = handle1.await.unwrap();
270 assert!(result1.is_err());
271
272 let result2 = handle2.await.unwrap();
273 assert_eq!(*result2.unwrap(), 10);
274 });
275}
276