uv_git_types/
oid.rs

1use std::fmt::{Display, Formatter};
2use std::str::{self, FromStr};
3
4use thiserror::Error;
5
6/// Unique identity of any Git object (commit, tree, blob, tag).
7///
8/// This type's `FromStr` implementation validates that it's exactly 40 hex characters, i.e. a
9/// full-length git commit.
10///
11/// If Git's SHA-256 support becomes more widespread in the future (in particular if GitHub ever
12/// adds support), we might need to make this an enum.
13#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
14pub struct GitOid {
15    bytes: [u8; 40],
16}
17
18impl GitOid {
19    /// Return the string representation of an object ID.
20    pub fn as_str(&self) -> &str {
21        str::from_utf8(&self.bytes).unwrap()
22    }
23
24    /// Return a truncated representation, i.e., the first 16 characters of the SHA.
25    pub fn as_short_str(&self) -> &str {
26        &self.as_str()[..16]
27    }
28
29    /// Return a (very) truncated representation, i.e., the first 8 characters of the SHA.
30    pub fn as_tiny_str(&self) -> &str {
31        &self.as_str()[..8]
32    }
33}
34
35#[derive(Debug, Error, PartialEq)]
36pub enum OidParseError {
37    #[error("Object ID cannot be parsed from empty string")]
38    Empty,
39    #[error("Object ID must be exactly 40 hex characters")]
40    WrongLength,
41    #[error("Object ID must be valid hex characters")]
42    NotHex,
43}
44
45impl FromStr for GitOid {
46    type Err = OidParseError;
47
48    fn from_str(s: &str) -> Result<Self, Self::Err> {
49        if s.is_empty() {
50            return Err(OidParseError::Empty);
51        }
52
53        if s.len() != 40 {
54            return Err(OidParseError::WrongLength);
55        }
56
57        if !s.chars().all(|ch| ch.is_ascii_hexdigit()) {
58            return Err(OidParseError::NotHex);
59        }
60
61        let mut bytes = [0; 40];
62        bytes.copy_from_slice(s.as_bytes());
63        Ok(Self { bytes })
64    }
65}
66
67impl Display for GitOid {
68    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
69        write!(f, "{}", self.as_str())
70    }
71}
72
73impl serde::Serialize for GitOid {
74    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
75    where
76        S: serde::Serializer,
77    {
78        self.as_str().serialize(serializer)
79    }
80}
81
82impl<'de> serde::Deserialize<'de> for GitOid {
83    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
84    where
85        D: serde::Deserializer<'de>,
86    {
87        struct Visitor;
88
89        impl serde::de::Visitor<'_> for Visitor {
90            type Value = GitOid;
91
92            fn expecting(&self, f: &mut Formatter) -> std::fmt::Result {
93                f.write_str("a string")
94            }
95
96            fn visit_str<E: serde::de::Error>(self, v: &str) -> Result<Self::Value, E> {
97                GitOid::from_str(v).map_err(serde::de::Error::custom)
98            }
99        }
100
101        deserializer.deserialize_str(Visitor)
102    }
103}
104
105#[cfg(test)]
106mod tests {
107    use std::str::FromStr;
108
109    use super::{GitOid, OidParseError};
110
111    #[test]
112    fn git_oid() {
113        GitOid::from_str("4a23745badf5bf5ef7928f1e346e9986bd696d82").unwrap();
114        GitOid::from_str("4A23745BADF5BF5EF7928F1E346E9986BD696D82").unwrap();
115
116        assert_eq!(GitOid::from_str(""), Err(OidParseError::Empty));
117        assert_eq!(
118            GitOid::from_str(&str::repeat("a", 41)),
119            Err(OidParseError::WrongLength)
120        );
121        assert_eq!(
122            GitOid::from_str(&str::repeat("a", 39)),
123            Err(OidParseError::WrongLength)
124        );
125        assert_eq!(
126            GitOid::from_str(&str::repeat("x", 40)),
127            Err(OidParseError::NotHex)
128        );
129    }
130}
uv_git_types/oid.rs

uv_git_types/
oid.rs
