wingfoil 3.0.1

graph based stream processing framework
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

use crate::types::*;

use derive_new::new;

use std::rc::Rc;

#[derive(new)]
pub(crate) struct FoldStream<IN: Element, OUT: Element> {
    upstream: Rc<dyn Stream<IN>>,
    func: Box<dyn Fn(&mut OUT, IN)>,
    #[new(default)]
    value: OUT,
}

impl<IN: Element, OUT: Element> MutableNode for FoldStream<IN, OUT> {
    fn cycle(&mut self, _state: &mut GraphState) -> anyhow::Result<bool> {
        (self.func)(&mut self.value, self.upstream.peek_value());
        Ok(true)
    }
    fn upstreams(&self) -> UpStreams {
        UpStreams::new(vec![self.upstream.clone().as_node()], vec![])
    }
}

impl<IN: Element, OUT: Element> StreamPeekRef<OUT> for FoldStream<IN, OUT> {
    fn peek_ref(&self) -> &OUT {
        &self.value
    }
}

#[cfg(test)]
mod tests {

    use crate::graph::*;
    use crate::nodes::*;
    use crate::time::NanoTime;
    use std::time::Duration;

    #[test]
    fn fold_sum_works() {
        let f = |a: &mut u64, b: u64| {
            *a += b;
        };
        let reduced = ticker(Duration::from_nanos(100)).count().fold(Box::new(f));
        let captured = reduced.clone().collect();
        assert_eq!(reduced.peek_value(), 0);
        captured
            .run(RunMode::HistoricalFrom(NanoTime::ZERO), RunFor::Cycles(4))
            .unwrap();
        let expected = vec![
            ValueAt {
                value: 1,
                time: NanoTime::new(0),
            }, // 0 + 1 = 1
            ValueAt {
                value: 3,
                time: NanoTime::new(100),
            }, // 1 + 2 = 3
            ValueAt {
                value: 6,
                time: NanoTime::new(200),
            }, // 3 + 3 = 6
            ValueAt {
                value: 10,
                time: NanoTime::new(300),
            }, // 6 + 4 = 10
        ];
        assert_eq!(expected, captured.peek_value());
        assert_eq!(10, reduced.peek_value());
    }

    #[test]
    fn fold_collect_works() {
        let f = |a: &mut Vec<u64>, b: u64| {
            a.push(b);
        };
        let reduced = ticker(Duration::from_nanos(100)).count().fold(Box::new(f));
        let captured = reduced.clone().collect();
        assert!(reduced.peek_value().is_empty());
        captured
            .run(RunMode::HistoricalFrom(NanoTime::ZERO), RunFor::Cycles(4))
            .unwrap();
        let expected = vec![
            ValueAt {
                value: vec![1],
                time: NanoTime::new(0),
            },
            ValueAt {
                value: vec![1, 2],
                time: NanoTime::new(100),
            },
            ValueAt {
                value: vec![1, 2, 3],
                time: NanoTime::new(200),
            },
            ValueAt {
                value: vec![1, 2, 3, 4],
                time: NanoTime::new(300),
            },
        ];
        assert_eq!(expected, captured.peek_value());
        assert_eq!(vec![1, 2, 3, 4], reduced.peek_value());
    }

    #[test]
    fn count() {
        let count = ticker(Duration::from_nanos(100)).count();
        let captured = count.clone().collect();
        assert_eq!(count.peek_value(), 0);
        captured
            .run(RunMode::HistoricalFrom(NanoTime::ZERO), RunFor::Cycles(3))
            .unwrap();
        let expected = vec![
            ValueAt {
                value: 1,
                time: NanoTime::new(0),
            },
            ValueAt {
                value: 2,
                time: NanoTime::new(100),
            },
            ValueAt {
                value: 3,
                time: NanoTime::new(200),
            },
        ];
        assert_eq!(expected, captured.peek_value());
        assert_eq!(3, count.peek_value());
    }
}