indicator 0.4.4

Abstractions for stream aggregation, we call them `Indicator` s.
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

#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};

use core::cmp::{Ord, Ordering, PartialOrd};
use time::OffsetDateTime;

use crate::TickValue;

#[cfg(feature = "serde")]
mod rfc3339 {
    use serde::{Deserializer, Serializer};
    use time::{serde::rfc3339, OffsetDateTime};

    /// Serialize an [`Option<OffsetDateTime>`] using the well-known RFC3339 format.
    pub(super) fn serialize<S: Serializer>(
        datetime: &Option<OffsetDateTime>,
        serializer: S,
    ) -> Result<S::Ok, S::Error> {
        match datetime {
            Some(datetime) => rfc3339::serialize(datetime, serializer),
            None => serializer.serialize_none(),
        }
    }

    /// Deserialize an [`OffsetDateTime`] from its RFC3339 representation.
    pub(super) fn deserialize<'a, D: Deserializer<'a>>(
        deserializer: D,
    ) -> Result<Option<OffsetDateTime>, D::Error> {
        struct Visitor;

        impl<'de> serde::de::Visitor<'de> for Visitor {
            type Value = Option<OffsetDateTime>;

            fn expecting(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
                write!(f, "a optional timestamp str in RFC3339 format")
            }

            fn visit_none<E>(self) -> Result<Self::Value, E>
            where
                E: serde::de::Error,
            {
                Ok(None)
            }

            fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
            where
                D: Deserializer<'de>,
            {
                Ok(Some(rfc3339::deserialize(deserializer)?))
            }
        }

        deserializer.deserialize_option(Visitor)
    }
}

/// A tick in time.
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Tick(#[cfg_attr(feature = "serde", serde(with = "rfc3339"))] Option<OffsetDateTime>);

impl Tick {
    /// "The Big Bang" tick.
    pub const BIG_BANG: Tick = Tick(None);

    /// Create a new tick.
    pub fn new(ts: OffsetDateTime) -> Self {
        Self(Some(ts))
    }

    /// Get the timestamp.
    pub fn ts(&self) -> Option<&OffsetDateTime> {
        self.0.as_ref()
    }

    /// With value.
    pub fn with_value<T>(self, value: T) -> TickValue<T> {
        TickValue { tick: self, value }
    }
}

impl From<OffsetDateTime> for Tick {
    fn from(value: OffsetDateTime) -> Self {
        Self::new(value)
    }
}

impl PartialOrd for Tick {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl Ord for Tick {
    fn cmp(&self, other: &Self) -> Ordering {
        match (self.0.as_ref(), other.0.as_ref()) {
            (Some(lhs), Some(rhs)) => lhs.cmp(rhs),
            (Some(_), None) => Ordering::Greater,
            (None, Some(_)) => Ordering::Less,
            (None, None) => Ordering::Equal,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_big_bang() {
        assert_eq!(Tick::BIG_BANG, Tick::BIG_BANG);
    }

    #[cfg(feature = "serde")]
    #[test]
    fn serialize_tick() {
        use time::macros::datetime;

        let tick = Tick::BIG_BANG;
        assert_eq!(serde_json::to_string(&tick).unwrap(), r#"null"#);

        let tick = Tick::new(datetime!(2022-09-26 01:23:45 +06:54));
        assert_eq!(
            serde_json::to_string(&tick).unwrap(),
            r#""2022-09-26T01:23:45+06:54""#
        );
    }

    #[cfg(feature = "serde")]
    #[test]
    fn deserialize_tick() {
        use time::macros::datetime;

        let tick = serde_json::from_str::<Tick>(r#"null"#).unwrap();
        assert_eq!(tick, Tick::BIG_BANG);

        let tick = serde_json::from_str::<Tick>(r#""2022-09-26T01:23:45+06:54""#).unwrap();
        assert_eq!(tick, Tick::new(datetime!(2022-09-26 01:23:45 +06:54)),);
    }
}