Add conversions for StorePath to harmonia

Only enabled with new feature "harmonia" due to harmonia's state of
flux.

nix-bindings-store/Cargo.toml

@@ -18,6 +18,7 @@ nix-bindings-util-sys = { path = "../nix-bindings-util-sys", version = "0.2.1" }
 nix-bindings-store-sys = { path = "../nix-bindings-store-sys", version = "0.2.1" }
 lazy_static = "1.4"
 zerocopy = "0.8"
+harmonia-store-core = { version = "0.0.0-alpha.0", optional = true }
 
 [dev-dependencies]
 ctor = "0.2"
@@ -30,6 +31,9 @@ pkg-config = "0.3"
 # Needed for version parsing in build.rs
 nix-bindings-util = { path = "../nix-bindings-util", version = "0.2.1" }
 
+[features]
+harmonia = [ "dep:harmonia-store-core" ]
+
 [lints.rust]
 warnings = "deny"
 dead-code = "allow"

nix-bindings-store/src/path/harmonia.rs

@@ -0,0 +1,65 @@
+use anyhow::{Context as _, Result};
+
+use super::{StorePath, STORE_PATH_HASH_SIZE};
+
+impl TryFrom<&harmonia_store_core::store_path::StorePath> for StorePath {
+    type Error = anyhow::Error;
+
+    fn try_from(harmonia_path: &harmonia_store_core::store_path::StorePath) -> Result<Self> {
+        let hash: &[u8; STORE_PATH_HASH_SIZE] = harmonia_path.hash().as_ref();
+        StorePath::from_parts(hash, harmonia_path.name().as_ref())
+    }
+}
+
+impl TryFrom<&StorePath> for harmonia_store_core::store_path::StorePath {
+    type Error = anyhow::Error;
+
+    fn try_from(nix_path: &StorePath) -> Result<Self> {
+        let hash = nix_path
+            .hash()
+            .context("Failed to get hash from nix StorePath")?;
+        let harmonia_hash = harmonia_store_core::store_path::StorePathHash::new(hash);
+
+        let name = nix_path
+            .name()
+            .context("Failed to get name from nix StorePath")?;
+
+        let harmonia_name: harmonia_store_core::store_path::StorePathName = name
+            .parse()
+            .context("Failed to parse name as StorePathName")?;
+
+        Ok(harmonia_store_core::store_path::StorePath::from((
+            harmonia_hash,
+            harmonia_name,
+        )))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    #[test]
+    fn store_path_round_trip_harmonia() {
+        let harmonia_path: harmonia_store_core::store_path::StorePath =
+            "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo.drv".parse().unwrap();
+
+        let nix_path: crate::path::StorePath = (&harmonia_path).try_into().unwrap();
+
+        let harmonia_round_trip: harmonia_store_core::store_path::StorePath =
+            (&nix_path).try_into().unwrap();
+
+        assert_eq!(harmonia_path, harmonia_round_trip);
+    }
+
+    #[test]
+    fn store_path_harmonia_clone() {
+        let harmonia_path: harmonia_store_core::store_path::StorePath =
+            "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo.drv".parse().unwrap();
+
+        let nix_path: crate::path::StorePath = (&harmonia_path).try_into().unwrap();
+        let cloned_path = nix_path.clone();
+
+        assert_eq!(nix_path.name().unwrap(), cloned_path.name().unwrap());
+        assert_eq!(nix_path.hash().unwrap(), cloned_path.hash().unwrap());
+    }
+}

nix-bindings-store/src/path/mod.rs

@@ -125,6 +125,9 @@ impl Drop for StorePath {
     }
 }
 
+#[cfg(all(feature = "harmonia", nix_at_least = "2.33"))]
+mod harmonia;
+
 #[cfg(test)]
 mod tests {
     use super::*;