tick 0.3.3

Provides primitives to interact with and manipulate machine time.
Documentation 
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

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

use std::time::{Duration, Instant};

use super::Clock;

/// A stopwatch that facilitates the measurement of elapsed time.
///
/// An instance of `Stopwatch` is created by calling [`Clock::stopwatch()`] or by passing
/// a [`Clock`] to the [`Stopwatch::new()`] constructor.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// use tick::Clock;
///
/// # fn measure(clock: &Clock) -> Duration {
/// let stopwatch = clock.stopwatch();
/// // Perform some operation...
/// stopwatch.elapsed()
/// # }
/// ```
#[derive(Debug)]
pub struct Stopwatch(StopwatchRepr);

#[derive(Debug)]
enum StopwatchRepr {
    #[cfg(not(any(feature = "test-util", test)))]
    System(Instant),
    #[cfg(any(feature = "test-util", test))]
    Clock(Clock, Instant),
}

impl Stopwatch {
    /// Creates a high-accuracy stopwatch that measures elapsed time.
    ///
    /// > **Note**: Consider using [`Clock::stopwatch()`] as a shortcut for creating stopwatches.
    ///
    /// # Examples
    ///
    /// ```
    /// use std::time::Duration;
    ///
    /// use tick::{Clock, Stopwatch};
    ///
    /// # fn measure(clock: &Clock) -> Duration {
    /// let stopwatch = Stopwatch::new(clock);
    /// // Perform some operation...
    /// stopwatch.elapsed()
    /// # }
    /// ```
    #[cfg_attr(
        not(any(feature = "test-util", test)),
        expect(unused_variables, reason = "intentionally not using self-references if test-util is disabled")
    )]
    #[must_use]
    pub fn new(clock: &Clock) -> Self {
        #[cfg(any(feature = "test-util", test))]
        let repr = StopwatchRepr::Clock(clock.clone(), clock.instant());

        #[cfg(not(any(feature = "test-util", test)))]
        let repr = StopwatchRepr::System(Instant::now());

        Self(repr)
    }

    /// Returns the elapsed time since the stopwatch was created.
    #[must_use]
    pub fn elapsed(&self) -> Duration {
        match &self.0 {
            #[cfg(not(any(feature = "test-util", test)))]
            StopwatchRepr::System(start) => start.elapsed(),

            #[cfg(any(feature = "test-util", test))]
            StopwatchRepr::Clock(clock, start) => clock.instant().saturating_duration_since(*start),
        }
    }
}

impl From<Stopwatch> for Instant {
    fn from(stopwatch: Stopwatch) -> Self {
        match stopwatch.0 {
            #[cfg(not(any(feature = "test-util", test)))]
            StopwatchRepr::System(start) => start,

            #[cfg(any(feature = "test-util", test))]
            StopwatchRepr::Clock(_, start) => start,
        }
    }
}

impl From<Stopwatch> for Duration {
    fn from(stopwatch: Stopwatch) -> Self {
        stopwatch.elapsed()
    }
}

#[cfg(test)]
mod test {
    use std::thread::sleep;

    use super::*;
    use crate::clock_control::ClockControl;

    #[test]
    fn assert_types() {
        static_assertions::assert_impl_all!(Stopwatch: Send, Sync);
    }

    #[test]
    fn test_stopwatch() {
        let clock = Clock::new_system_frozen();
        let watch = clock.stopwatch();

        sleep(Duration::from_millis(1));

        let elapsed = watch.elapsed();
        assert!(elapsed >= Duration::from_millis(1));
    }

    #[test]
    fn test_stopwatch_with_control() {
        let control = ClockControl::new();
        let clock = control.to_clock();

        let watch = clock.stopwatch();
        sleep(Duration::from_millis(1));
        assert_eq!(watch.elapsed(), Duration::ZERO);

        control.advance(Duration::from_secs(1));
        assert_eq!(watch.elapsed(), Duration::from_secs(1));
    }

    #[test]
    fn test_stopwatch_into_instance() {
        let clock = Clock::new_frozen();
        let watch = clock.stopwatch();

        let instant: Instant = watch.into();
        assert_eq!(instant, clock.instant());
    }

    #[test]
    fn test_stopwatch_into_duration() {
        let control = ClockControl::new();
        let clock = control.to_clock();
        let watch = clock.stopwatch();
        control.advance(Duration::from_secs(1));

        let duration: Duration = watch.into();
        assert_eq!(duration, Duration::from_secs(1));
    }
}