oid: New crate

For further details on the crate see its documentation in
`crates/radicle-oid/src/lib.rs`.

Changes to `crates/radicle{,-crypto}/Cargo.toml` are to preserve the
default features of their dependencies `serde` and `schemars`,
which are disabled to support `radicle-oid` being `no_std`.

Cargo.lock

@@ -2960,6 +2960,19 @@ dependencies = [
  "winpipe",
 ]
 
+[[package]]
+name = "radicle-oid"
+version = "0.1.0"
+dependencies = [
+ "git2",
+ "gix-hash",
+ "qcheck",
+ "qcheck-macros",
+ "radicle-git-ref-format",
+ "schemars",
+ "serde",
+]
+
 [[package]]
 name = "radicle-protocol"
 version = "0.4.0"

Cargo.toml

@@ -29,6 +29,7 @@ cyphernet = "0.5.2"
 dunce = "1.0.5"
 fastrand = { version = "2.0.0", default-features = false }
 git-ref-format-core = { version = "0.3.0", default-features = false }
+git-ref-format = { version = "0.3.0", default-features = false }
 git2 = { version = "0.19.0", default-features = false }
 human-panic = "2"
 itertools = "0.14"
@@ -49,14 +50,16 @@ radicle-crypto = { version = "0.14", path = "crates/radicle-crypto" }
 radicle-dag = { version = "0.10", path = "crates/radicle-dag" }
 radicle-fetch = { version = "0.16", path = "crates/radicle-fetch" }
 radicle-git-ext = { version = "0.8", default-features = false }
+radicle-git-ref-format = { version = "0.1.0", path = "crates/radicle-git-ref-format", default-features = false }
 radicle-node = { version = "0.16", path = "crates/radicle-node" }
+radicle-oid = { version = "0.1.0", path = "crates/radicle-oid", default-features = false }
 radicle-protocol = { version = "0.4", path = "crates/radicle-protocol" }
 radicle-signals = { version = "0.11", path = "crates/radicle-signals" }
 radicle-ssh = { version = "0.10", path = "crates/radicle-ssh", default-features = false }
 radicle-systemd = { version = "0.11", path = "crates/radicle-systemd" }
 radicle-term = { version = "0.16", path = "crates/radicle-term" }
-schemars = { version = "1.0.4" }
+schemars = { version = "1.0.4", default-features = false }
-serde = "1.0"
+serde = { version = "1.0", default-features = false }
 serde_json = "1.0"
 shlex = "1.1.0"
 signature = "2.2"

crates/radicle-crypto/Cargo.toml

@@ -25,7 +25,7 @@ multibase = { workspace = true }
 qcheck = { workspace = true, optional = true }
 git-ref-format-core = { workspace = true, optional = true }
 radicle-ssh = { workspace = true, optional = true }
-serde = { workspace = true, features = ["derive"] }
+serde = { workspace = true, features = ["derive", "std"] }
 signature = { workspace = true }
 sqlite = { workspace = true, features = ["bundled"], optional = true }
 ssh-key = { version = "0.6.3", default-features = false, features = ["std", "encryption", "getrandom"], optional = true }

crates/radicle-oid/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+name = "radicle-oid"
+description = "Radicle representation of Git object identifiers"
+homepage.workspace = true
+repository.workspace = true
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+keywords = ["radicle", "git", "oid"]
+rust-version.workspace = true
+
+# For documentation of features refer to the module documentation in `./lib.rs`
+[features]
+default = ["sha1", "std"]
+gix = ["dep:gix-hash"]
+std = []
+sha1 = []
+
+[dependencies]
+git2 = { workspace = true, optional = true, default-features = false }
+gix-hash = { version = "0.15.1", optional = true, default-features = false }
+qcheck = { workspace = true, optional = true, default-features = false }
+radicle-git-ref-format = { workspace = true, optional = true, default-features = false }
+schemars = { workspace = true, optional = true, default-features = false }
+serde = { workspace = true, optional = true, default-features = false }
+
+[dev-dependencies]
+git2 = { workspace = true }
+gix-hash = { version = "0.15.1" }
+qcheck = { workspace = true }
+qcheck-macros = { workspace = true }

crates/radicle-oid/src/lib.rs

@@ -0,0 +1,575 @@
+#![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.");
+
+const SHA1_DIGEST_LEN: usize = 20;
+
+#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Copy)]
+#[non_exhaustive]
+pub enum Oid {
+    Sha1([u8; SHA1_DIGEST_LEN]),
+}
+
+/// 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 {
+    pub fn from_sha1(digest: [u8; SHA1_DIGEST_LEN]) -> Self {
+        Self::Sha1(digest)
+    }
+
+    pub fn into_sha1(&self) -> Option<[u8; SHA1_DIGEST_LEN]> {
+        match self {
+            Oid::Sha1(digest) => Some(*digest),
+        }
+    }
+
+    pub fn sha1_zero() -> Self {
+        Self::Sha1([0u8; SHA1_DIGEST_LEN])
+    }
+}
+
+/// 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(ref array) => array.iter().all(|b| *b == 0),
+        }
+    }
+}
+
+impl AsRef<[u8]> for Oid {
+    fn as_ref(&self) -> &[u8] {
+        match self {
+            Oid::Sha1(ref 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, SHA1_DIGEST_LEN};
+    use core::str;
+
+    /// Length of the string representation of a SHA-1 digest in hexadecimal notation.
+    pub(super) const SHA1_DIGEST_STR_LEN: usize = SHA1_DIGEST_LEN * 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; SHA1_DIGEST_LEN];
+            for i in 0..SHA1_DIGEST_LEN {
+                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::sha1_zero()
+            );
+        }
+
+        #[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::sha1_zero().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) {
+                state.write(self.as_ref());
+            }
+        }
+    }
+}
+
+#[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),
+            }
+        }
+    }
+
+    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,
+            }
+        }
+    }
+
+    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::sha1_zero() == 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::sha1_zero() == 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 {
+                let slice = [0u8; SHA1_DIGEST_LEN];
+                g.fill(slice);
+                Self::Sha1(slice)
+            }
+        }
+    }
+}
+
+#[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 {
+                        use crate::str::SHA1_DIGEST_STR_LEN;
+                        write!(f, "a Git object identifier (SHA-1 digest in hexadecimal notation; {SHA1_DIGEST_STR_LEN} characters; {SHA1_DIGEST_LEN} bytes)")
+                    }
+
+                    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::{json_schema, JsonSchema, Schema, SchemaGenerator};
+
+    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, SHA1_DIGEST_LEN};
+            json_schema!({
+                "description": format!("A Git object identifier (SHA-1 digest in hexadecimal notation; {SHA1_DIGEST_STR_LEN} characters; {SHA1_DIGEST_LEN} bytes)"),
+                "type": "string",
+                "maxLength": SHA1_DIGEST_STR_LEN,
+                "minLength": SHA1_DIGEST_STR_LEN,
+                "pattern":  format!("^[0-9a-fA-F]{{{SHA1_DIGEST_STR_LEN}}}$"),
+            })
+        }
+    }
+}

crates/radicle/Cargo.toml

@@ -36,7 +36,7 @@ radicle-cob = { workspace = true }
 radicle-crypto = { workspace = true, features = ["git-ref-format-core", "ssh", "sqlite", "cyphernet"] }
 radicle-git-ext = { workspace = true, features = ["serde"] }
 radicle-ssh = { workspace = true }
-schemars = { workspace = true, optional = true }
+schemars = { workspace = true, optional = true, features = ["derive", "std"] }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true, features = ["preserve_order"] }
 serde-untagged = "0.1.7"