witchcraft_metrics/
clock.rs

1// Copyright 2020 Palantir Technologies, Inc.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14use once_cell::sync::Lazy;
15use std::sync::Arc;
16use std::time::Instant;
17
18pub(crate) static SYSTEM_CLOCK: Lazy<Arc<SystemClock>> = Lazy::new(|| Arc::new(SystemClock));
19
20/// A source of monotonic time.
21pub trait Clock: 'static + Sync + Send {
22    /// Returns the current time.
23    fn now(&self) -> Instant;
24}
25
26/// A `Clock` implementation which uses the system clock.
27pub struct SystemClock;
28
29impl Clock for SystemClock {
30    #[inline]
31    fn now(&self) -> Instant {
32        Instant::now()
33    }
34}
35
36#[cfg(test)]
37pub mod test {
38    use super::*;
39    use parking_lot::Mutex;
40    use std::time::Duration;
41
42    pub struct TestClock {
43        now: Mutex<Instant>,
44    }
45
46    impl TestClock {
47        #[allow(clippy::new_without_default)]
48        pub fn new() -> TestClock {
49            TestClock {
50                now: Mutex::new(Instant::now()),
51            }
52        }
53
54        pub fn advance(&self, dur: Duration) {
55            *self.now.lock() += dur;
56        }
57    }
58
59    impl Clock for TestClock {
60        fn now(&self) -> Instant {
61            *self.now.lock()
62        }
63    }
64}
witchcraft_metrics/clock.rs

witchcraft_metrics/
clock.rs
