posy 0.0.1

[wip] Python installer and package manager
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

use crate::prelude::*;

#[derive(Debug, Clone, PartialEq, Eq, Hash, SerializeDisplay, DeserializeFromStr)]
pub struct ArtifactHash {
    pub mode: String,
    pub raw_data: Vec<u8>,
}

impl ArtifactHash {
    pub fn from_hex(mode: &str, hex: &str) -> Result<ArtifactHash> {
        Ok(ArtifactHash {
            mode: mode.into(),
            raw_data: data_encoding::HEXLOWER_PERMISSIVE.decode(hex.as_bytes())?,
        })
    }

    pub fn checker<'a, T: Write>(&'a self, inner: T) -> Result<HashChecker<'a, T>> {
        let algorithm = match self.mode.as_str() {
            "sha256" => &ring::digest::SHA256,
            _ => bail!("unknown hash algorithm {}", self.mode),
        };
        let state = ring::digest::Context::new(algorithm);
        Ok(HashChecker {
            inner,
            state,
            expected: self,
        })
    }
}

impl Display for ArtifactHash {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "{}={}",
            self.mode,
            data_encoding::HEXLOWER.encode(&self.raw_data),
        )
    }
}

impl TryFrom<&str> for ArtifactHash {
    type Error = eyre::Report;

    fn try_from(value: &str) -> Result<Self, Self::Error> {
        let (mode, data) = value
            .split_once('=')
            .ok_or(eyre!("expected = in hash string {:?}", value))?;
        Ok(ArtifactHash::from_hex(mode, data)?)
    }
}

try_from_str_boilerplate!(ArtifactHash);

pub struct HashChecker<'a, T: Write> {
    inner: T,
    state: ring::digest::Context,
    expected: &'a ArtifactHash,
}

impl<'a, T: Write> HashChecker<'a, T> {
    pub fn finish(self) -> Result<T> {
        let digest = self.state.finish();
        if &self.expected.raw_data != digest.as_ref() {
            bail!("hash mismatch: {:?} != {:?}", self.expected, digest);
        }
        Ok(self.inner)
    }
}

impl<'a, T: Write> Write for HashChecker<'a, T> {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        let written = self.inner.write(&buf)?;
        self.state.update(&buf[..written]);
        Ok(written)
    }

    fn flush(&mut self) -> std::io::Result<()> {
        self.inner.flush()
    }
}

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

    #[test]
    fn test_artifact_hash() {
        let value = ArtifactHash::from_hex(
            "sha256",
            "c27c231e66336183c484fbfe080fa6cc954149366c15dc21db8b7290081ec7b8",
        )
        .unwrap();
        assert_eq!(
            value.to_string(),
            "sha256=c27c231e66336183c484fbfe080fa6cc954149366c15dc21db8b7290081ec7b8"
        );

        let json = serde_json::to_string(&value).unwrap();
        let new_value: ArtifactHash = serde_json::from_str(&json).unwrap();
        assert_eq!(value, new_value);
    }

    #[test]
    fn test_hash_checker() {
        let gold_data = b"a drop of golden sun";
        let good_hash = ArtifactHash::from_hex(
            "sha256",
            "9c7ed1509d1809656c86aa1201fde2650ec056ab79f6546ba8205f6e42cff949",
        )
        .unwrap();
        let bad_hash = ArtifactHash::from_hex(
            "sha256",
            "007ed1509d1809656c86aa1201fde2650ec056ab79f6546ba8205f6e42cff949",
        )
        .unwrap();

        let buf = Vec::<u8>::new();
        let mut good_checker = good_hash.checker(buf).unwrap();
        assert!(good_checker.write_all(gold_data).is_ok());
        assert!(good_checker.flush().is_ok());
        let unwrapped = good_checker.finish().unwrap();
        assert_eq!(unwrapped.as_slice(), gold_data);

        let buf = Vec::<u8>::new();
        let mut bad_checker = bad_hash.checker(buf).unwrap();
        assert!(bad_checker.write_all(gold_data).is_ok());
        assert!(bad_checker.flush().is_ok());
        assert!(bad_checker.finish().is_err());
    }
}