notify_future/
lib.rs

1use std::future::Future;
2use std::sync::{Mutex, Arc};
3use std::pin::Pin;
4use std::task::{Poll, Context, Waker};
5
6struct NotifyFutureState<RESULT> {
7    waker: Option<Waker>,
8    result: Option<RESULT>,
9}
10
11impl <RESULT> NotifyFutureState<RESULT> {
12    pub fn new() -> Arc<Mutex<NotifyFutureState<RESULT>>> {
13        Arc::new(Mutex::new(NotifyFutureState {
14            waker: None,
15            result: None
16        }))
17    }
18
19    pub fn set_complete(state: &Arc<Mutex<NotifyFutureState<RESULT>>>, result: RESULT) {
20        let mut state = state.lock().unwrap();
21        state.result = Some(result);
22        if state.waker.is_some() {
23            state.waker.take().unwrap().wake();
24        }
25    }
26}
27
28#[deprecated(
29    since = "0.2.1",
30    note = "Please use Notify instead"
31)]
32pub struct NotifyFuture<RESULT> {
33    state:Arc<Mutex<NotifyFutureState<RESULT>>>
34}
35
36impl<RESULT> Clone for NotifyFuture<RESULT> {
37    fn clone(&self) -> Self {
38        Self {
39            state: self.state.clone()
40        }
41    }
42}
43
44impl <RESULT> NotifyFuture<RESULT> {
45    pub fn new() -> Self {
46        Self{
47            state: NotifyFutureState::new()
48        }
49    }
50
51    pub fn set_complete(&self, result: RESULT) {
52        NotifyFutureState::set_complete(&self.state, result);
53    }
54}
55
56impl <RESULT> Future for NotifyFuture<RESULT> {
57    type Output = RESULT;
58
59    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
60        let mut state = self.state.lock().unwrap();
61        if state.result.is_some() {
62            return Poll::Ready(state.result.take().unwrap());
63        }
64
65        if state.waker.is_none() {
66            state.waker = Some(cx.waker().clone());
67        }
68        Poll::Pending
69    }
70}
71
72pub struct Notify<RESULT> {
73    state: Arc<Mutex<NotifyFutureState<RESULT>>>
74}
75
76impl<RESULT> Notify<RESULT> {
77    pub fn new() -> (Self, NotifyWaiter<RESULT>) {
78        let state = NotifyFutureState::new();
79        (Self {
80            state: state.clone()
81        }, NotifyWaiter::new(state))
82    }
83
84    pub fn notify(self, result: RESULT) {
85        NotifyFutureState::set_complete(&self.state, result);
86    }
87}
88
89pub struct NotifyWaiter<RESULT> {
90    state: Arc<Mutex<NotifyFutureState<RESULT>>>
91}
92
93impl<RESULT> NotifyWaiter<RESULT> {
94    pub(crate) fn new(state: Arc<Mutex<NotifyFutureState<RESULT>>>) -> Self {
95        Self {
96            state
97        }
98    }
99}
100
101impl <RESULT> Future for NotifyWaiter<RESULT> {
102    type Output = RESULT;
103
104    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
105        let mut state = self.state.lock().unwrap();
106        if state.result.is_some() {
107            return Poll::Ready(state.result.take().unwrap());
108        }
109
110        if state.waker.is_none() || !state.waker.as_ref().unwrap().will_wake(cx.waker()) {
111            state.waker = Some(cx.waker().clone());
112        }
113        Poll::Pending
114    }
115}
116
117#[cfg(test)]
118mod test {
119    use std::time::Duration;
120    use crate::{Notify, NotifyFuture};
121
122    #[test]
123    fn test() {
124        async_std::task::block_on(async {
125            let notify_future = NotifyFuture::<u32>::new();
126            let tmp_future = notify_future.clone();
127            async_std::task::spawn(async move {
128                async_std::task::sleep(Duration::from_secs(3)).await;
129                tmp_future.set_complete(1);
130            });
131            let ret = notify_future.await;
132            assert_eq!(ret, 1);
133        });
134    }
135
136    #[test]
137    fn test2() {
138        async_std::task::block_on(async {
139            let (notify, waiter) = Notify::<u32>::new();
140            async_std::task::spawn(async move {
141                async_std::task::sleep(Duration::from_secs(3)).await;
142                notify.notify(1);
143            });
144            let ret = waiter.await;
145            assert_eq!(ret, 1);
146        });
147    }
148}
notify_future/lib.rs

notify_future/
lib.rs
