clean up

fix/src/nix_utils.rs

@@ -0,0 +1,21 @@
+use nix_compat::store_path::compress_hash;
+use sha2::{Digest as _, Sha256};
+
+pub fn sha256_hex(data: &[u8]) -> String {
+    let mut hasher = Sha256::new();
+    hasher.update(data);
+    hex::encode(hasher.finalize())
+}
+
+pub fn make_store_path(store_dir: &str, ty: &str, hash_hex: &str, name: &str) -> String {
+    let s = format!("{}:sha256:{}:{}:{}", ty, hash_hex, store_dir, name);
+
+    let mut hasher = Sha256::new();
+    hasher.update(s.as_bytes());
+    let hash: [u8; 32] = hasher.finalize().into();
+
+    let compressed = compress_hash::<20>(&hash);
+    let encoded = nix_compat::nixbase32::encode(&compressed);
+
+    format!("{}/{}-{}", store_dir, encoded, name)
+}