#![no_std]
//! This is a `no_std` crate which carries the struct [`Oid`] that represents
//! Git object identifiers. Currently, only SHA-1 digests are supported.
//!
//! # Feature Flags
//!
//! The default features are `sha1` and `std`.
//!
//! ## `sha1`
//!
//! Enabled by default, since SHA-1 is commonly used. Currently, this feature is
//! also *required* to build the crate. In the future, after support for other
//! hashes is added, it might become possible to build the crate without support
//! for SHA-1.
//!
//! ## `std`
//!
//! [`Hash`]: ::doc_std::hash::Hash
//!
//! Enabled by default, since it is expected that most dependents will use the
//! standard library.
//!
//! Provides an implementation of [`Hash`].
//!
//! ## `git2`
//!
//! [`git2::Oid`]: ::git2::Oid
//!
//! Provides conversions to/from [`git2::Oid`].
//!
//! Note that as of version 0.19.0,
//!
//! ## `gix`
//!
//! [`ObjectId`]: ::gix_hash::ObjectId
//!
//! Provides conversions to/from [`ObjectId`].
//!
//! ## `schemars`
//!
//! [`JsonSchema`]: ::schemars::JsonSchema
//!
//! Provides an implementation of [`JsonSchema`].
//!
//! ## `serde`
//!
//! [`Serialize`]: ::serde::ser::Serialize
//! [`Deserialize`]: ::serde::de::Deserialize
//!
//! Provides implementations of [`Serialize`] and [`Deserialize`].
//!
//! ## `qcheck`
//!
//! [`qcheck::Arbitrary`]: ::qcheck::Arbitrary
//!
//! Provides an implementation of [`qcheck::Arbitrary`].
//!
//! ## `radicle-git-ref-format`
//!
//! [`radicle_git_ref_format::Component`]: ::radicle_git_ref_format::Component
//! [`radicle_git_ref_format::RefString`]: ::radicle_git_ref_format::RefString
//!
//! Conversion to [`radicle_git_ref_format::Component`]
//! (and also [`radicle_git_ref_format::RefString`]).
#[cfg(doc)]
extern crate std as doc_std;
extern crate alloc;
// Remove this once other hashes (e.g., SHA-256, and potentially others)
// are supported, and this crate can build without [`Oid::Sha1`].
#[cfg(not(feature = "sha1"))]
compile_error!("The `sha1` feature is required.");
#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Copy)]
#[non_exhaustive]
pub enum Oid {
Sha1([u8; Self::LEN_SHA1]),
}
/// Conversions to/from SHA-1.
// Note that we deliberately do not implement `From<[u8; 20]>` and `Into<[u8; 20]>`,
// for forwards compatibility: What if another hash with digests of the same
// length becomes popular?
impl Oid {
/// The length of a SHA-1 object identifier in bytes.
pub const LEN_SHA1: usize = 20;
/// A SHA-1 object identifier with all digest bytes set to zero.
/// This is sometimes used as a sentinel value to indicate the absence of
/// an object.
/// To compare whether an object identifier is zero, prefer the method
/// [`Oid::is_zero`] over checking equality with this constant.
pub const ZERO_SHA1: Self = Self::Sha1([0u8; Self::LEN_SHA1]);
pub fn from_sha1(digest: [u8; Self::LEN_SHA1]) -> Self {
Self::Sha1(digest)
}
pub fn into_sha1(&self) -> Option<[u8; Self::LEN_SHA1]> {
match self {
Oid::Sha1(digest) => Some(*digest),
}
}
}
/// Interaction with zero.
impl Oid {
/// Test whether all bytes in this object identifier are zero.
/// See also [`::git2::Oid::is_zero`].
pub fn is_zero(&self) -> bool {
match self {
Oid::Sha1(array) => array.iter().all(|b| *b == 0),
}
}
}
impl AsRef<[u8]> for Oid {
fn as_ref(&self) -> &[u8] {
match self {
Oid::Sha1(array) => array,
}
}
}
impl From<Oid> for alloc::boxed::Box<[u8]> {
fn from(oid: Oid) -> Self {
match oid {
Oid::Sha1(array) => alloc::boxed::Box::new(array),
}
}
}
pub mod str {
use super::Oid;
use core::str;
/// Length of the string representation of a SHA-1 digest in hexadecimal notation.
pub(super) const SHA1_DIGEST_STR_LEN: usize = Oid::LEN_SHA1 * 2;
impl str::FromStr for Oid {
type Err = error::ParseOidError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
use error::ParseOidError::*;
let len = s.len();
if len != SHA1_DIGEST_STR_LEN {
return Err(Len(len));
}
let mut bytes = [0u8; Oid::LEN_SHA1];
for i in 0..Oid::LEN_SHA1 {
bytes[i] = u8::from_str_radix(&s[i * 2..=i * 2 + 1], 16)
.map_err(|source| At { index: i, source })?;
}
Ok(Self::Sha1(bytes))
}
}
pub mod error {
use core::{fmt, num};
use super::SHA1_DIGEST_STR_LEN;
pub enum ParseOidError {
Len(usize),
At {
index: usize,
source: num::ParseIntError,
},
}
impl fmt::Display for ParseOidError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
use ParseOidError::*;
match self {
Len(len) => {
write!(f, "invalid length (have {len}, want {SHA1_DIGEST_STR_LEN})")
}
At { index, source } => write!(
f,
"parse error at byte {index} (characters {} and {}): {source}",
index * 2,
index * 2 + 1
),
}
}
}
impl fmt::Debug for ParseOidError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(self, f)
}
}
impl core::error::Error for ParseOidError {
fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
match self {
ParseOidError::At { source, .. } => Some(source),
_ => None,
}
}
}
}
pub use error::ParseOidError;
#[cfg(test)]
mod test {
use super::*;
use alloc::string::ToString;
use qcheck_macros::quickcheck;
#[test]
fn fixture() {
assert_eq!(
"123456789abcdef0123456789abcdef012345678"
.parse::<Oid>()
.unwrap(),
Oid::from_sha1([
0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78,
])
);
}
#[test]
fn zero() {
assert_eq!(
"0000000000000000000000000000000000000000"
.parse::<Oid>()
.unwrap(),
Oid::ZERO_SHA1
);
}
#[quickcheck]
fn git2_roundtrip(oid: Oid) {
let other = git2::Oid::from(oid);
let other = other.to_string();
let other = other.parse::<Oid>().unwrap();
assert_eq!(oid, other);
}
#[quickcheck]
fn gix_roundrip(oid: Oid) {
let other = gix_hash::ObjectId::from(oid);
let other = other.to_string();
let other = other.parse::<Oid>().unwrap();
assert_eq!(oid, other);
}
}
}
mod fmt {
use alloc::format;
use core::fmt;
use super::Oid;
impl fmt::Display for Oid {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Oid::Sha1(digest) =>
// SAFETY (for all 20 blocks below): The length of `digest` is
// known to be `SHA1_DIGEST_LEN`, which is 20.
// The indices below are manually verified to not be out of bounds.
format!(
"{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}{:02x}",
unsafe { digest.get_unchecked(0) },
unsafe { digest.get_unchecked(1) },
unsafe { digest.get_unchecked(2) },
unsafe { digest.get_unchecked(3) },
unsafe { digest.get_unchecked(4) },
unsafe { digest.get_unchecked(5) },
unsafe { digest.get_unchecked(6) },
unsafe { digest.get_unchecked(7) },
unsafe { digest.get_unchecked(8) },
unsafe { digest.get_unchecked(9) },
unsafe { digest.get_unchecked(10) },
unsafe { digest.get_unchecked(11) },
unsafe { digest.get_unchecked(12) },
unsafe { digest.get_unchecked(13) },
unsafe { digest.get_unchecked(14) },
unsafe { digest.get_unchecked(15) },
unsafe { digest.get_unchecked(16) },
unsafe { digest.get_unchecked(17) },
unsafe { digest.get_unchecked(18) },
unsafe { digest.get_unchecked(19) },
).fmt(f)
}
}
}
impl fmt::Debug for Oid {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(self, f)
}
}
#[cfg(test)]
mod test {
use super::*;
use alloc::string::ToString;
use qcheck_macros::quickcheck;
#[test]
fn fixture() {
assert_eq!(
Oid::from_sha1([
0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78, 0x9a,
0xbc, 0xde, 0xf0, 0x12, 0x34, 0x56, 0x78,
])
.to_string(),
"123456789abcdef0123456789abcdef012345678"
);
}
#[test]
fn zero() {
assert_eq!(
Oid::ZERO_SHA1.to_string(),
"0000000000000000000000000000000000000000"
);
}
#[quickcheck]
fn git2(oid: Oid) {
assert_eq!(oid.to_string(), git2::Oid::from(oid).to_string());
}
#[quickcheck]
fn gix(oid: Oid) {
assert_eq!(oid.to_string(), gix_hash::ObjectId::from(oid).to_string());
}
}
}
#[cfg(feature = "std")]
mod std {
extern crate std;
use super::Oid;
mod hash {
use std::hash;
use super::*;
#[allow(clippy::derived_hash_with_manual_eq)]
impl hash::Hash for Oid {
fn hash<H: hash::Hasher>(&self, state: &mut H) {
let bytes: &[u8] = self.as_ref();
std::hash::Hash::hash(bytes, state)
}
}
}
}
#[cfg(any(feature = "gix", test))]
mod gix {
use gix_hash::ObjectId as Other;
use super::Oid;
impl From<Other> for Oid {
fn from(other: Other) -> Self {
match other {
Other::Sha1(digest) => Self::Sha1(digest),
_ => unimplemented!("conversion from {other:?} into radicle_oid::Oid"),
}
}
}
impl From<Oid> for Other {
fn from(oid: Oid) -> Other {
match oid {
Oid::Sha1(digest) => Other::Sha1(digest),
}
}
}
impl core::cmp::PartialEq<Other> for Oid {
fn eq(&self, other: &Other) -> bool {
match (self, other) {
(Oid::Sha1(a), Other::Sha1(b)) => a == b,
_ => unimplemented!("conversion from {other:?} into radicle_oid::Oid"),
}
}
}
impl AsRef<gix_hash::oid> for Oid {
fn as_ref(&self) -> &gix_hash::oid {
match self {
Oid::Sha1(digest) => gix_hash::oid::from_bytes_unchecked(digest),
}
}
}
#[cfg(test)]
mod test {
use super::*;
use gix_hash::Kind;
#[test]
fn zero() {
assert!(Oid::ZERO_SHA1 == Other::null(Kind::Sha1));
}
}
}
#[cfg(any(feature = "git2", test))]
mod git2 {
use ::git2::Oid as Other;
use super::*;
const EXPECT: &str = "git2::Oid must be exactly 20 bytes long";
impl From<Other> for Oid {
fn from(other: Other) -> Self {
Self::Sha1(other.as_bytes().try_into().expect(EXPECT))
}
}
impl From<Oid> for Other {
fn from(oid: Oid) -> Self {
match oid {
Oid::Sha1(array) => Other::from_bytes(&array).expect(EXPECT),
}
}
}
impl From<&Oid> for Other {
fn from(oid: &Oid) -> Self {
match oid {
Oid::Sha1(array) => Other::from_bytes(array).expect(EXPECT),
}
}
}
impl core::cmp::PartialEq<Other> for Oid {
fn eq(&self, other: &Other) -> bool {
other.as_bytes() == AsRef::<[u8]>::as_ref(&self)
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn zero() {
assert!(Oid::ZERO_SHA1 == Other::zero());
}
}
}
#[cfg(any(test, feature = "qcheck"))]
mod test {
mod qcheck {
use ::qcheck::{Arbitrary, Gen};
use crate::*;
impl Arbitrary for Oid {
fn arbitrary(g: &mut Gen) -> Self {
Self::Sha1(<[u8; Oid::LEN_SHA1]>::arbitrary(g))
}
}
}
}
#[cfg(feature = "serde")]
mod serde {
mod ser {
use ::serde::ser;
use crate::*;
impl ser::Serialize for Oid {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: ser::Serializer,
{
serializer.collect_str(self)
}
}
}
mod de {
use core::fmt;
use ::serde::de;
use crate::*;
impl<'de> de::Deserialize<'de> for Oid {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: de::Deserializer<'de>,
{
struct OidVisitor;
impl<'de> de::Visitor<'de> for OidVisitor {
type Value = Oid;
fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(
f,
"a Git object identifier (SHA-1 digest in hexadecimal notation; {} characters; {} bytes)",
crate::str::SHA1_DIGEST_STR_LEN,
Oid::LEN_SHA1
)
}
fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
where
E: de::Error,
{
s.parse().map_err(de::Error::custom)
}
}
deserializer.deserialize_str(OidVisitor)
}
}
}
}
#[cfg(feature = "radicle-git-ref-format")]
mod radicle_git_ref_format {
use ::radicle_git_ref_format::{Component, RefString};
use super::*;
impl From<&Oid> for Component<'_> {
fn from(id: &Oid) -> Self {
Component::from_refstr(RefString::from(id))
.expect("Git object identifiers are valid component strings")
}
}
impl From<&Oid> for RefString {
fn from(id: &Oid) -> Self {
RefString::try_from(alloc::format!("{id}"))
.expect("Git object identifiers are valid reference strings")
}
}
}
#[cfg(feature = "schemars")]
mod schemars {
use alloc::{borrow::Cow, format};
use ::schemars::{JsonSchema, Schema, SchemaGenerator, json_schema};
use super::Oid;
impl JsonSchema for Oid {
fn schema_name() -> Cow<'static, str> {
"Oid".into()
}
fn schema_id() -> Cow<'static, str> {
concat!(module_path!(), "::Oid").into()
}
fn json_schema(_: &mut SchemaGenerator) -> Schema {
use crate::str::SHA1_DIGEST_STR_LEN;
json_schema!({
"description": format!(
"A Git object identifier (SHA-1 digest in hexadecimal notation; {SHA1_DIGEST_STR_LEN} characters; {} bytes)",
Oid::LEN_SHA1,
),
"type": "string",
"maxLength": SHA1_DIGEST_STR_LEN,
"minLength": SHA1_DIGEST_STR_LEN,
"pattern": format!("^[0-9a-fA-F]{{{SHA1_DIGEST_STR_LEN}}}$"),
})
}
}
}