wlan_common/
timer.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use fuchsia_async as fasync;
use futures::channel::mpsc;
use futures::{FutureExt, Stream, StreamExt};

use crate::sink::UnboundedSink;

pub type ScheduledEvent<E> = (zx::MonotonicInstant, Event<E>);
pub type EventSender<E> = UnboundedSink<ScheduledEvent<E>>;
pub type EventStream<E> = mpsc::UnboundedReceiver<ScheduledEvent<E>>;
pub type EventId = u64;

// The returned timer will send scheduled timeouts to the returned EventStream.
// Note that this will not actually have any timed behavior unless events are pulled off
// the EventStream and handled asynchronously.
pub fn create_timer<E>() -> (Timer<E>, EventStream<E>) {
    let (timer_sink, time_stream) = mpsc::unbounded();
    (Timer::new(UnboundedSink::new(timer_sink)), time_stream)
}

pub fn make_async_timed_event_stream<E>(
    time_stream: impl Stream<Item = ScheduledEvent<E>>,
) -> impl Stream<Item = Event<E>> {
    time_stream
        .map(|(deadline, timed_event)| {
            fasync::Timer::new(fasync::MonotonicInstant::from_zx(deadline)).map(|_| timed_event)
        })
        .buffer_unordered(usize::max_value())
}

#[derive(Debug)]
pub struct Event<E> {
    pub id: EventId,
    pub event: E,
}

impl<E: Clone> Clone for Event<E> {
    fn clone(&self) -> Self {
        Event { id: self.id, event: self.event.clone() }
    }
}

#[derive(Debug)]
pub struct Timer<E> {
    sender: EventSender<E>,
    next_id: EventId,
}

impl<E> Timer<E> {
    pub fn new(sender: EventSender<E>) -> Self {
        Timer { sender, next_id: 0 }
    }

    /// Returns the current time according to the global executor.
    ///
    /// # Panics
    ///
    /// This function will panic if it's called when no executor is set up.
    pub fn now(&self) -> zx::MonotonicInstant {
        // We use fasync to support time manipulation in tests.
        fasync::MonotonicInstant::now().into_zx()
    }

    pub fn schedule_at(&mut self, deadline: zx::MonotonicInstant, event: E) -> EventId {
        let id = self.next_id;
        self.sender.send((deadline, Event { id, event }));
        self.next_id += 1;
        id
    }

    pub fn schedule_after(&mut self, duration: zx::MonotonicDuration, event: E) -> EventId {
        self.schedule_at(fasync::MonotonicInstant::after(duration).into_zx(), event)
    }

    pub fn schedule<EV>(&mut self, event: EV) -> EventId
    where
        EV: TimeoutDuration + Into<E>,
    {
        self.schedule_after(event.timeout_duration(), event.into())
    }
}

pub trait TimeoutDuration {
    fn timeout_duration(&self) -> zx::MonotonicDuration;
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::assert_variant;
    use fuchsia_async as fasync;

    use futures::channel::mpsc::UnboundedSender;
    use std::pin::pin;
    use std::task::Poll;

    type TestEvent = u32;
    impl TimeoutDuration for TestEvent {
        fn timeout_duration(&self) -> zx::MonotonicDuration {
            zx::MonotonicDuration::from_seconds(10)
        }
    }

    #[test]
    fn test_timer_schedule_at() {
        let _exec = fasync::TestExecutor::new();
        let (mut timer, mut time_stream) = create_timer::<TestEvent>();
        let timeout1 = zx::MonotonicInstant::after(zx::MonotonicDuration::from_seconds(5));
        let timeout2 = zx::MonotonicInstant::after(zx::MonotonicDuration::from_seconds(10));
        assert_eq!(timer.schedule_at(timeout1, 7), 0);
        assert_eq!(timer.schedule_at(timeout2, 9), 1);

        let (t1, event1) = time_stream.try_next().unwrap().expect("expect time entry");
        assert_eq!(t1, timeout1);
        assert_eq!(event1.id, 0);
        assert_eq!(event1.event, 7);

        let (t2, event2) = time_stream.try_next().unwrap().expect("expect time entry");
        assert_eq!(t2, timeout2);
        assert_eq!(event2.id, 1);
        assert_eq!(event2.event, 9);

        assert_variant!(time_stream.try_next(), Err(e) => {
            assert_eq!(e.to_string(), "receiver channel is empty")
        });
    }

    #[test]
    fn test_timer_schedule_after() {
        let _exec = fasync::TestExecutor::new();
        let (mut timer, mut time_stream) = create_timer::<TestEvent>();
        let timeout1 = zx::MonotonicDuration::from_seconds(1000);
        let timeout2 = zx::MonotonicDuration::from_seconds(5);
        assert_eq!(timer.schedule_after(timeout1, 7), 0);
        assert_eq!(timer.schedule_after(timeout2, 9), 1);

        let (t1, event1) = time_stream.try_next().unwrap().expect("expect time entry");
        assert_eq!(event1.id, 0);
        assert_eq!(event1.event, 7);

        let (t2, event2) = time_stream.try_next().unwrap().expect("expect time entry");
        assert_eq!(event2.id, 1);
        assert_eq!(event2.event, 9);

        // Confirm that the ordering of timeouts is expected. We can't check the actual
        // values since they're dependent on the system clock.
        assert!(t1.into_nanos() > t2.into_nanos());

        assert_variant!(time_stream.try_next(), Err(e) => {
            assert_eq!(e.to_string(), "receiver channel is empty")
        });
    }

    #[test]
    fn test_timer_schedule() {
        let _exec = fasync::TestExecutor::new();
        let (mut timer, mut time_stream) = create_timer::<TestEvent>();
        let start = zx::MonotonicInstant::after(zx::MonotonicDuration::from_millis(0));

        assert_eq!(timer.schedule(5u32), 0);

        let (t, event) = time_stream.try_next().unwrap().expect("expect time entry");
        assert_eq!(event.id, 0);
        assert_eq!(event.event, 5);
        assert!(start + zx::MonotonicDuration::from_seconds(10) <= t);
    }

    #[test]
    fn test_timer_stream() {
        let mut exec = fasync::TestExecutor::new_with_fake_time();
        let fut = async {
            let (timer, time_stream) = mpsc::unbounded::<ScheduledEvent<TestEvent>>();
            let mut timeout_stream = make_async_timed_event_stream(time_stream);
            let now = zx::MonotonicInstant::get();
            schedule(&timer, now + zx::MonotonicDuration::from_millis(40), 0);
            schedule(&timer, now + zx::MonotonicDuration::from_millis(10), 1);
            schedule(&timer, now + zx::MonotonicDuration::from_millis(20), 2);
            schedule(&timer, now + zx::MonotonicDuration::from_millis(30), 3);

            let mut events = vec![];
            for _ in 0u32..4 {
                let event = timeout_stream.next().await.expect("timer terminated prematurely");
                events.push(event.event);
            }
            events
        };
        let mut fut = pin!(fut);
        for _ in 0u32..4 {
            assert_eq!(Poll::Pending, exec.run_until_stalled(&mut fut));
            assert!(exec.wake_next_timer().is_some());
        }
        assert_variant!(
            exec.run_until_stalled(&mut fut),
            Poll::Ready(events) => assert_eq!(events, vec![1, 2, 3, 0]),
        );
    }

    fn schedule(
        timer: &UnboundedSender<ScheduledEvent<TestEvent>>,
        deadline: zx::MonotonicInstant,
        event: TestEvent,
    ) {
        let entry = (deadline, Event { id: 0, event });
        timer.unbounded_send(entry).expect("expect send successful");
    }
}