rustdis 0.1.1

A partial Redis server implementation intended purely for educational purposes
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

use std::sync::{Arc, Mutex};

use crate::commands::executable::Executable;
use crate::commands::CommandParser;
use crate::frame::Frame;
use crate::store::Store;
use crate::Error;

/// Increment the string representing a floating point number stored at key by the specified
/// increment. By using a negative increment value, the result is that the value stored at the key
/// is decremented (by the obvious properties of addition). If the key does not exist, it is set to
/// 0 before performing the operation.
///
/// Ref: <https://redis.io/docs/latest/commands/incrbyfloat/>
///
/// TODO:
/// * Handle overflow errors.
/// * The precision of the output is fixed at 17 digits after the decimal point regardless of the
///   actual internal precision of the computation.
/// * Both the value already contained in the string key and the increment argument can be
///   optionally provided in exponential notation.

#[derive(Debug, PartialEq)]
pub struct IncrByFloat {
    pub key: String,
    pub increment: f64,
}

impl Executable for IncrByFloat {
    fn exec(self, store: Arc<Mutex<Store>>) -> Result<Frame, Error> {
        let res = store.lock().unwrap().incr_by(&self.key, self.increment);

        match res {
            Ok(res) => Ok(Frame::Simple(res.to_string())),
            Err(msg) => Ok(Frame::Error(msg.to_string())),
        }
    }
}

impl TryFrom<&mut CommandParser> for IncrByFloat {
    type Error = Error;

    fn try_from(parser: &mut CommandParser) -> Result<Self, Self::Error> {
        let key = parser.next_string()?;
        let increment = parser.next_float()?;

        Ok(Self { key, increment })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::commands::Command;
    use bytes::Bytes;

    #[test]
    fn existing_key() {
        let store = Arc::new(Mutex::new(Store::new()));

        let frame = Frame::Array(vec![
            Frame::Bulk(Bytes::from("INCRBYFLOAT")),
            Frame::Bulk(Bytes::from("key1")),
            Frame::Bulk(Bytes::from("0.1")),
        ]);
        let cmd = Command::try_from(frame).unwrap();

        assert_eq!(
            cmd,
            Command::IncrByFloat(IncrByFloat {
                key: "key1".to_string(),
                increment: 0.1,
            })
        );

        store
            .lock()
            .unwrap()
            .set(String::from("key1"), Bytes::from("10.50"));

        let result = cmd.exec(store.clone()).unwrap();

        assert_eq!(result, Frame::Simple("10.6".to_string()));
        assert_eq!(
            store.lock().unwrap().get("key1"),
            Some(&Bytes::from("10.6"))
        );
    }

    #[test]
    fn non_existing_key() {
        let store = Arc::new(Mutex::new(Store::new()));

        let frame = Frame::Array(vec![
            Frame::Bulk(Bytes::from("INCRBYFLOAT")),
            Frame::Bulk(Bytes::from("key1")),
            Frame::Integer(10),
        ]);
        let cmd = Command::try_from(frame).unwrap();

        assert_eq!(
            cmd,
            Command::IncrByFloat(IncrByFloat {
                key: "key1".to_string(),
                increment: 10.00,
            })
        );

        let result = cmd.exec(store.clone()).unwrap();

        assert_eq!(result, Frame::Simple("10".to_string()));
        assert_eq!(store.lock().unwrap().get("key1"), Some(&Bytes::from("10")));
    }

    #[test]
    fn invalid_key_type() {
        let store = Arc::new(Mutex::new(Store::new()));

        let frame = Frame::Array(vec![
            Frame::Bulk(Bytes::from("INCRBYFLOAT")),
            Frame::Bulk(Bytes::from("key1")),
            Frame::Integer(10),
        ]);
        let cmd = Command::try_from(frame).unwrap();

        assert_eq!(
            cmd,
            Command::IncrByFloat(IncrByFloat {
                key: "key1".to_string(),
                increment: 10.00,
            })
        );

        store
            .lock()
            .unwrap()
            .set(String::from("key1"), Bytes::from("value"));

        let result = cmd.exec(store.clone()).unwrap();

        assert_eq!(
            result,
            Frame::Error("value is not of the correct type or out of range".to_string())
        );

        assert_eq!(
            store.lock().unwrap().get("key1"),
            Some(&Bytes::from("value"))
        );
    }
}