feat: Store::realise, Store::add_derivation, Store::derivation_from_json

rust/nix-bindings-store/src/derivation.rs

@@ -0,0 +1,21 @@
+use nix_bindings_bindgen_raw as raw;
+use std::ptr::NonNull;
+
+/// A Nix derivation
+pub struct Derivation {
+    pub(crate) inner: NonNull<raw::derivation>,
+}
+
+impl Derivation {
+    pub(crate) fn new_raw(inner: NonNull<raw::derivation>) -> Self {
+        Derivation { inner }
+    }
+}
+
+impl Drop for Derivation {
+    fn drop(&mut self) {
+        unsafe {
+            raw::derivation_free(self.inner.as_ptr());
+        }
+    }
+}