gix_hash/
kind.rs

1use std::str::FromStr;
2
3use crate::{oid, Kind, ObjectId};
4
5#[cfg(feature = "sha1")]
6use crate::{SIZE_OF_SHA1_DIGEST, SIZE_OF_SHA1_HEX_DIGEST};
7
8#[cfg(feature = "sha256")]
9use crate::{SIZE_OF_SHA256_DIGEST, SIZE_OF_SHA256_HEX_DIGEST};
10
11impl TryFrom<u8> for Kind {
12    type Error = u8;
13
14    fn try_from(value: u8) -> Result<Self, Self::Error> {
15        Ok(match value {
16            #[cfg(feature = "sha1")]
17            1 => Kind::Sha1,
18            #[cfg(feature = "sha256")]
19            2 => Kind::Sha256,
20            unknown => return Err(unknown),
21        })
22    }
23}
24
25impl FromStr for Kind {
26    type Err = String;
27
28    fn from_str(s: &str) -> Result<Self, Self::Err> {
29        Ok(match s {
30            #[cfg(feature = "sha1")]
31            "sha1" | "SHA1" | "SHA-1" => Kind::Sha1,
32            #[cfg(feature = "sha256")]
33            "sha256" | "SHA256" | "SHA-256" => Kind::Sha256,
34            other => return Err(other.into()),
35        })
36    }
37}
38
39impl std::fmt::Display for Kind {
40    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
41        match self {
42            #[cfg(feature = "sha1")]
43            Kind::Sha1 => f.write_str("sha1"),
44            #[cfg(feature = "sha256")]
45            Kind::Sha256 => f.write_str("sha256"),
46        }
47    }
48}
49
50impl Kind {
51    /// Returns the shortest hash we support.
52    #[inline]
53    pub const fn shortest() -> Self {
54        #[cfg(all(not(feature = "sha1"), feature = "sha256"))]
55        {
56            Self::Sha256
57        }
58        #[cfg(feature = "sha1")]
59        {
60            Self::Sha1
61        }
62    }
63
64    /// Returns the longest hash we support.
65    #[inline]
66    pub const fn longest() -> Self {
67        #[cfg(feature = "sha256")]
68        {
69            Self::Sha256
70        }
71        #[cfg(all(not(feature = "sha256"), feature = "sha1"))]
72        {
73            Self::Sha1
74        }
75    }
76
77    /// Returns a buffer suitable to hold the longest possible hash in hex.
78    #[inline]
79    pub const fn hex_buf() -> [u8; Kind::longest().len_in_hex()] {
80        [0u8; Kind::longest().len_in_hex()]
81    }
82
83    /// Returns a buffer suitable to hold the longest possible hash as raw bytes.
84    #[inline]
85    pub const fn buf() -> [u8; Kind::longest().len_in_bytes()] {
86        [0u8; Kind::longest().len_in_bytes()]
87    }
88
89    /// Returns the amount of bytes needed to encode this instance as hexadecimal characters.
90    #[inline]
91    pub const fn len_in_hex(&self) -> usize {
92        match self {
93            #[cfg(feature = "sha1")]
94            Kind::Sha1 => SIZE_OF_SHA1_HEX_DIGEST,
95            #[cfg(feature = "sha256")]
96            Kind::Sha256 => SIZE_OF_SHA256_HEX_DIGEST,
97        }
98    }
99
100    /// Returns the amount of bytes taken up by the hash of this instance.
101    #[inline]
102    pub const fn len_in_bytes(&self) -> usize {
103        match self {
104            #[cfg(feature = "sha1")]
105            Kind::Sha1 => SIZE_OF_SHA1_DIGEST,
106            #[cfg(feature = "sha256")]
107            Kind::Sha256 => SIZE_OF_SHA256_DIGEST,
108        }
109    }
110
111    /// Returns the kind of hash that would fit the given `hex_len`, or `None` if there is no fitting hash.
112    /// Note that `0` as `hex_len` up to 40 always yields SHA-1 while anything in the range 41..64
113    /// always yields SHA-256 if it is enabled.
114    #[inline]
115    pub const fn from_hex_len(hex_len: usize) -> Option<Self> {
116        Some(match hex_len {
117            #[cfg(feature = "sha1")]
118            0..=SIZE_OF_SHA1_HEX_DIGEST => Kind::Sha1,
119            #[cfg(feature = "sha256")]
120            0..=SIZE_OF_SHA256_HEX_DIGEST => Kind::Sha256,
121            _ => return None,
122        })
123    }
124
125    /// Converts a size in bytes as obtained by `Kind::len_in_bytes()` into the corresponding hash kind, if possible.
126    ///
127    /// **Panics** if the hash length doesn't match a known hash.
128    ///
129    /// NOTE that this method isn't public as it shouldn't be encouraged to assume all hashes have the same length.
130    /// However, if there should be such a thing, our `oid` implementation will have to become an enum and it's pretty breaking
131    /// to the way it's currently being used as auto-dereffing doesn't work anymore. Let's hope it won't happen.
132    // TODO: make 'const' once Rust 1.57 is more readily available in projects using 'gitoxide'.
133    #[inline]
134    pub(crate) fn from_len_in_bytes(bytes: usize) -> Self {
135        match bytes {
136            #[cfg(feature = "sha1")]
137            SIZE_OF_SHA1_DIGEST => Kind::Sha1,
138            #[cfg(feature = "sha256")]
139            SIZE_OF_SHA256_DIGEST => Kind::Sha256,
140            _ => panic!("BUG: must be called only with valid hash lengths produced by len_in_bytes()"),
141        }
142    }
143
144    /// Create a shared null-id of our hash kind.
145    #[inline]
146    pub fn null_ref(&self) -> &'static oid {
147        match self {
148            #[cfg(feature = "sha1")]
149            Kind::Sha1 => oid::null_sha1(),
150            #[cfg(feature = "sha256")]
151            Kind::Sha256 => oid::null_sha256(),
152        }
153    }
154
155    /// Create an owned null-id of our hash kind.
156    #[inline]
157    pub const fn null(&self) -> ObjectId {
158        match self {
159            #[cfg(feature = "sha1")]
160            Kind::Sha1 => ObjectId::null_sha1(),
161            #[cfg(feature = "sha256")]
162            Kind::Sha256 => ObjectId::null_sha256(),
163        }
164    }
165
166    /// The hash of an empty blob.
167    #[inline]
168    pub const fn empty_blob(&self) -> ObjectId {
169        ObjectId::empty_blob(*self)
170    }
171
172    /// The hash of an empty tree.
173    #[inline]
174    pub const fn empty_tree(&self) -> ObjectId {
175        ObjectId::empty_tree(*self)
176    }
177}
gix_hash/kind.rs

gix_hash/
kind.rs
