1 files changed, 37 insertions, 0 deletions
diff --git a/tvix/castore/src/fs/root_nodes.rs b/tvix/castore/src/fs/root_nodes.rs
new file mode 100644
index 0000000000..6609e049a1
--- /dev/null
+++ b/tvix/castore/src/fs/root_nodes.rs
@@ -0,0 +1,37 @@
+use std::collections::BTreeMap;
+
+use crate::{proto::node::Node, Error};
+use bytes::Bytes;
+use futures::stream::BoxStream;
+use tonic::async_trait;
+
+/// Provides an interface for looking up root nodes  in tvix-castore by given
+/// a lookup key (usually the basename), and optionally allow a listing.
+#[async_trait]
+pub trait RootNodes: Send + Sync {
+    /// Looks up a root CA node based on the basename of the node in the root
+    /// directory of the filesystem.
+    async fn get_by_basename(&self, name: &[u8]) -> Result<Option<Node>, Error>;
+
+    /// Lists all root CA nodes in the filesystem. An error can be returned
+    /// in case listing is not allowed
+    fn list(&self) -> BoxStream<Result<Node, Error>>;
+}
+
+#[async_trait]
+/// Implements RootNodes for something deref'ing to a BTreeMap of Nodes, where
+/// the key is the node name.
+impl<T> RootNodes for T
+where
+    T: AsRef<BTreeMap<Bytes, Node>> + Send + Sync,
+{
+    async fn get_by_basename(&self, name: &[u8]) -> Result<Option<Node>, Error> {
+        Ok(self.as_ref().get(name).cloned())
+    }
+
+    fn list(&self) -> BoxStream<Result<Node, Error>> {
+        Box::pin(tokio_stream::iter(
+            self.as_ref().iter().map(|(_, v)| Ok(v.clone())),
+        ))
+    }
+}