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

use std::str::FromStr;
use thiserror::Error as ThisError;

#[derive(Debug, ThisError)]
pub enum Error {
    #[error("Invalid version - {0}")]
    MalformedVersion(String),
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
/// Structure representing API version used to determine compatibility between a client and a server.
pub struct ApiVersion {
    major: usize,
    minor: usize,
    patch: usize,
}

impl ApiVersion {
    pub const fn new(major: usize, minor: usize, patch: usize) -> Self {
        Self {
            major,
            minor,
            patch,
        }
    }

    pub fn major(&self) -> usize {
        self.major
    }

    pub fn minor(&self) -> usize {
        self.minor
    }

    pub fn patch(&self) -> usize {
        self.patch
    }

    pub fn make_endpoint(&self, ep: impl AsRef<str>) -> String {
        let ep = ep.as_ref();
        format!(
            "/v{}{}{}",
            self,
            if !ep.starts_with('/') { "/" } else { "" },
            ep
        )
    }
}

impl std::fmt::Display for ApiVersion {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}.{}", self.major, self.minor)
    }
}

impl From<usize> for ApiVersion {
    fn from(v: usize) -> Self {
        ApiVersion {
            major: v,
            minor: 0,
            patch: 0,
        }
    }
}

impl From<(usize, usize)> for ApiVersion {
    fn from(v: (usize, usize)) -> Self {
        ApiVersion {
            major: v.0,
            minor: v.1,
            patch: 0,
        }
    }
}

impl From<(usize, usize, usize)> for ApiVersion {
    fn from(v: (usize, usize, usize)) -> Self {
        ApiVersion {
            major: v.0,
            minor: v.1,
            patch: v.2,
        }
    }
}

impl FromStr for ApiVersion {
    type Err = Error;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let mut elems = s.split('.');
        macro_rules! parse_or_err {
            ($s:expr) => {
                if let Some(it) = elems.next() {
                    match it.parse::<usize>() {
                        Ok(it) => it,
                        Err(e) => return Err(Error::MalformedVersion(e.to_string())),
                    }
                } else {
                    return Err(Error::MalformedVersion($s.to_string()));
                }
            };
        }
        let major = parse_or_err!("expected major version");
        let minor = parse_or_err!("expected minor version");
        let patch = parse_or_err!("expected patch version");

        if elems.next().is_some() {
            return Err(Error::MalformedVersion(
                "unexpected extra tokens".to_string(),
            ));
        }

        Ok(Self {
            major,
            minor,
            patch,
        })
    }
}