plckit 0.1.2

Kit for PLCs and real-time micro-services
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
157
158
159
160
161
162
163
164
165
166

use bma_ts::Monotonic;
use std::{ops::Deref, time::Duration};

pub struct TtlCell<T> {
    value: Option<T>,
    ttl: Duration,
    set_at: Monotonic,
}

impl<T> TtlCell<T> {
    #[inline]
    pub fn new(ttl: Duration) -> Self {
        Self {
            value: None,
            ttl,
            set_at: Monotonic::now(),
        }
    }
    #[inline]
    pub fn new_with_value(ttl: Duration, value: T) -> Self {
        Self {
            value: Some(value),
            ttl,
            set_at: Monotonic::now(),
        }
    }
    #[inline]
    pub fn replace(&mut self, value: T) -> Option<T> {
        let prev = self.value.replace(value);
        let result = if self.expired() { None } else { prev };
        self.touch();
        result
    }
    #[inline]
    pub fn set(&mut self, value: T) {
        self.value = Some(value);
        self.touch();
    }
    #[inline]
    pub fn clear(&mut self) {
        self.value = None;
    }
    #[inline]
    pub fn as_ref(&self) -> Option<&T> {
        if self.expired() {
            None
        } else {
            self.value.as_ref()
        }
    }
    #[inline]
    pub fn as_ref_with<'a, O>(
        &'a self,
        other: &'a TtlCell<O>,
        max_time_delta: Duration,
    ) -> Option<(&T, &O)> {
        let maybe_first = self.as_ref();
        let maybe_second = other.as_ref();
        if let Some(first) = maybe_first {
            if let Some(second) = maybe_second {
                if self.set_at.abs_diff(other.set_at) <= max_time_delta {
                    return Some((first, second));
                }
            }
        }
        None
    }
    #[inline]
    pub fn take(&mut self) -> Option<T> {
        if self.expired() {
            None
        } else {
            self.value.take()
        }
    }
    #[inline]
    pub fn take_with<O>(
        &mut self,
        other: &mut TtlCell<O>,
        max_time_delta: Duration,
    ) -> Option<(T, O)> {
        let maybe_first = self.take();
        let maybe_second = other.take();
        if let Some(first) = maybe_first {
            if let Some(second) = maybe_second {
                if self.set_at.abs_diff(other.set_at) <= max_time_delta {
                    return Some((first, second));
                }
            }
        }
        None
    }
    #[inline]
    pub fn as_deref(&self) -> Option<&T::Target>
    where
        T: Deref,
    {
        match self.as_ref() {
            Some(t) => Some(&**t),
            None => None,
        }
    }
    #[inline]
    pub fn expired(&self) -> bool {
        self.set_at.elapsed() > self.ttl
    }
    #[inline]
    pub fn touch(&mut self) {
        self.set_at = Monotonic::now();
    }
    #[inline]
    pub fn set_at(&self) -> Monotonic {
        self.set_at
    }
}

#[cfg(test)]
mod test {
    use std::{thread, time::Duration};

    use super::TtlCell;

    #[test]
    fn test_get_set() {
        let ttl = Duration::from_millis(10);
        let mut opt = TtlCell::new_with_value(ttl, 25);
        thread::sleep(ttl / 2);
        assert_eq!(opt.as_ref().copied(), Some(25));
        thread::sleep(ttl);
        assert_eq!(opt.as_ref().copied(), None);
        opt.set(30);
        thread::sleep(ttl / 2);
        assert_eq!(opt.as_ref().copied(), Some(30));
        thread::sleep(ttl);
        assert_eq!(opt.as_ref().copied(), None);
    }
    #[test]
    fn test_take_replace() {
        let ttl = Duration::from_millis(10);
        let mut opt = TtlCell::new_with_value(ttl, 25);
        thread::sleep(ttl / 2);
        assert_eq!(opt.take(), Some(25));
        assert_eq!(opt.as_ref().copied(), None);
        opt.set(30);
        thread::sleep(ttl / 2);
        assert_eq!(opt.replace(29), Some(30));
        assert_eq!(opt.as_ref().copied(), Some(29));
        thread::sleep(ttl);
        assert_eq!(opt.as_ref().copied(), None);
    }
    #[test]
    fn test_take_with() {
        let mut first = TtlCell::new_with_value(Duration::from_secs(1), 25);
        thread::sleep(Duration::from_millis(10));
        let mut second = TtlCell::new_with_value(Duration::from_secs(1), 25);
        assert!(first
            .take_with(&mut second, Duration::from_millis(100))
            .is_some());
        let mut first = TtlCell::new_with_value(Duration::from_secs(1), 25);
        thread::sleep(Duration::from_millis(100));
        let mut second = TtlCell::new_with_value(Duration::from_secs(1), 25);
        assert!(first
            .take_with(&mut second, Duration::from_millis(50))
            .is_none());
    }
}