uv_git_types/
oid.rs

1use std::fmt::{Debug, 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, and normalizes the object ID to lowercase.
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(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
35impl Debug for GitOid {
36    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
37        write!(f, "GitOid(\"{}\")", self.as_str())
38    }
39}
40
41#[derive(Debug, Error, PartialEq)]
42pub enum OidParseError {
43    #[error("Object ID cannot be parsed from empty string")]
44    Empty,
45    #[error("Object ID must be exactly 40 hex characters")]
46    WrongLength,
47    #[error("Object ID must be valid hex characters")]
48    NotHex,
49}
50
51impl FromStr for GitOid {
52    type Err = OidParseError;
53
54    fn from_str(s: &str) -> Result<Self, Self::Err> {
55        if s.is_empty() {
56            return Err(OidParseError::Empty);
57        }
58
59        if s.len() != 40 {
60            return Err(OidParseError::WrongLength);
61        }
62
63        if !s.chars().all(|ch| ch.is_ascii_hexdigit()) {
64            return Err(OidParseError::NotHex);
65        }
66
67        let mut bytes = [0; 40];
68        bytes.copy_from_slice(s.as_bytes());
69        bytes.make_ascii_lowercase();
70        Ok(Self { bytes })
71    }
72}
73
74impl Display for GitOid {
75    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
76        write!(f, "{}", self.as_str())
77    }
78}
79
80impl serde::Serialize for GitOid {
81    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
82    where
83        S: serde::Serializer,
84    {
85        self.as_str().serialize(serializer)
86    }
87}
88
89impl<'de> serde::Deserialize<'de> for GitOid {
90    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
91    where
92        D: serde::Deserializer<'de>,
93    {
94        struct Visitor;
95
96        impl serde::de::Visitor<'_> for Visitor {
97            type Value = GitOid;
98
99            fn expecting(&self, f: &mut Formatter) -> std::fmt::Result {
100                f.write_str("a string")
101            }
102
103            fn visit_str<E: serde::de::Error>(self, v: &str) -> Result<Self::Value, E> {
104                GitOid::from_str(v).map_err(serde::de::Error::custom)
105            }
106        }
107
108        deserializer.deserialize_str(Visitor)
109    }
110}
111
112#[cfg(test)]
113mod tests {
114    use std::str::FromStr;
115
116    use super::{GitOid, OidParseError};
117
118    #[test]
119    fn git_oid() -> Result<(), OidParseError> {
120        assert_eq!(
121            GitOid::from_str("4a23745badf5bf5ef7928f1e346e9986bd696d82")?,
122            GitOid::from_str("4A23745BADF5BF5EF7928F1E346E9986BD696D82")?
123        );
124
125        assert_eq!(GitOid::from_str(""), Err(OidParseError::Empty));
126        assert_eq!(
127            GitOid::from_str(&str::repeat("a", 41)),
128            Err(OidParseError::WrongLength)
129        );
130        assert_eq!(
131            GitOid::from_str(&str::repeat("a", 39)),
132            Err(OidParseError::WrongLength)
133        );
134        assert_eq!(
135            GitOid::from_str(&str::repeat("x", 40)),
136            Err(OidParseError::NotHex)
137        );
138
139        Ok(())
140    }
141}
uv_git_types/oid.rs

uv_git_types/
oid.rs
