refactor(tvix/castore): remove `name` from Nodes r/8504

Nodes only have names if they're contained inside a Directory, or if
they're a root node and have something else possibly giving them a name
externally.

This removes all `name` fields in the three different Nodes, and instead
maintains it inside a BTreeMap inside the Directory.

It also removes the NamedNode trait (they don't have a get_name()), as
well as Node::rename(self, name), and all [Partial]Ord implementations
for Node (as they don't have names to use for sorting).

The `nodes()`, `directories()`, `files()` iterators inside a `Directory`
now return a tuple of Name and Node, as does the RootNodesProvider.

The different {Directory,File,Symlink}Node struct constructors got
simpler, and the {Directory,File}Node ones became infallible - as
there's no more possibility to represent invalid state.

The proto structs stayed the same - there's now from_name_and_node and
into_name_and_node to convert back and forth between the two `Node`
structs.

Some further cleanups:

The error types for Node validation were renamed. Everything related to
names is now in the DirectoryError (not yet happy about the naming)

There's some leftover cleanups to do:
 - There should be a from_(sorted_)iter and into_iter in Directory, so
   we can construct and deconstruct in one go.
   That should also enable us to implement conversions from and to the
   proto representation that moves, rather than clones.

 - The BuildRequest and PathInfo structs are still proto-based, so we
   still do a bunch of conversions back and forth there (and have some
   ugly expect there). There's not much point for error handling here,
   this will be moved to stricter types in a followup CL.

Change-Id: I7369a8e3a426f44419c349077cb4fcab2044ebb6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12205
Tested-by: BuildkiteCI
Reviewed-by: yuka <yuka@yuka.dev>
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: benjaminedwardwebb <benjaminedwardwebb@gmail.com>
Reviewed-by: Connor Brewster <cbrewster@hey.com>

4 files changed, 33 insertions, 20 deletions

diff --git a/tvix/store/src/pathinfoservice/fs/mod.rs b/tvix/store/src/pathinfoservice/fs/mod.rs
index 9a991a41d28d..7a46e1fc8fa5 100644
--- a/tvix/store/src/pathinfoservice/fs/mod.rs
+++ b/tvix/store/src/pathinfoservice/fs/mod.rs
@@ -3,7 +3,7 @@ use futures::StreamExt;
 use tonic::async_trait;
 use tvix_castore::fs::{RootNodes, TvixStoreFs};
 use tvix_castore::{blobservice::BlobService, directoryservice::DirectoryService};
-use tvix_castore::{Error, Node, ValidateNodeError};
+use tvix_castore::{Error, Node};
 
 use super::PathInfoService;
 
@@ -58,25 +58,31 @@ where
             .get(*store_path.digest())
             .await?
             .map(|path_info| {
-                path_info
+                let node = path_info
                     .node
                     .as_ref()
                     .expect("missing root node")
-                    .try_into()
-                    .map_err(|e: ValidateNodeError| Error::StorageError(e.to_string()))
+                    .to_owned();
+
+                match node.into_name_and_node() {
+                    Ok((_name, node)) => Ok(node),
+                    Err(e) => Err(Error::StorageError(e.to_string())),
+                }
             })
             .transpose()?)
     }
 
-    fn list(&self) -> BoxStream<Result<Node, Error>> {
+    fn list(&self) -> BoxStream<Result<(bytes::Bytes, Node), Error>> {
         Box::pin(self.0.as_ref().list().map(|result| {
             result.and_then(|path_info| {
-                path_info
+                let node = path_info
                     .node
                     .as_ref()
                     .expect("missing root node")
-                    .try_into()
-                    .map_err(|e: ValidateNodeError| Error::StorageError(e.to_string()))
+                    .to_owned();
+
+                node.into_name_and_node()
+                    .map_err(|e| Error::StorageError(e.to_string()))
             })
         }))
     }
diff --git a/tvix/store/src/pathinfoservice/grpc.rs b/tvix/store/src/pathinfoservice/grpc.rs
index 187d9a148472..7510ccd911f0 100644
--- a/tvix/store/src/pathinfoservice/grpc.rs
+++ b/tvix/store/src/pathinfoservice/grpc.rs
@@ -132,9 +132,10 @@ where
         let path_info = self
             .grpc_client
             .clone()
-            .calculate_nar(tvix_castore::proto::Node {
-                node: Some(root_node.into()),
-            })
+            .calculate_nar(tvix_castore::proto::Node::from_name_and_node(
+                "".into(),
+                root_node.to_owned(),
+            ))
             .await
             .map_err(|e| Error::StorageError(e.to_string()))?
             .into_inner();
diff --git a/tvix/store/src/pathinfoservice/lru.rs b/tvix/store/src/pathinfoservice/lru.rs
index 3a7f01eb70ac..695c04636089 100644
--- a/tvix/store/src/pathinfoservice/lru.rs
+++ b/tvix/store/src/pathinfoservice/lru.rs
@@ -108,11 +108,17 @@ mod test {
             let mut p = PATHINFO_1.clone();
             let root_node = p.node.as_mut().unwrap();
             if let castorepb::Node { node: Some(node) } = root_node {
-                let n = node.to_owned();
-                *node = (&tvix_castore::Node::try_from(&n)
-                    .unwrap()
-                    .rename("11111111111111111111111111111111-dummy2".into()))
-                    .into();
+                match node {
+                    castorepb::node::Node::Directory(n) => {
+                        n.name = "11111111111111111111111111111111-dummy2".into()
+                    }
+                    castorepb::node::Node::File(n) => {
+                        n.name = "11111111111111111111111111111111-dummy2".into()
+                    }
+                    castorepb::node::Node::Symlink(n) => {
+                        n.name = "11111111111111111111111111111111-dummy2".into()
+                    }
+                }
             } else {
                 unreachable!()
             }
diff --git a/tvix/store/src/pathinfoservice/nix_http.rs b/tvix/store/src/pathinfoservice/nix_http.rs
index c10b97857ea1..5f1eed1a0a9f 100644
--- a/tvix/store/src/pathinfoservice/nix_http.rs
+++ b/tvix/store/src/pathinfoservice/nix_http.rs
@@ -228,10 +228,10 @@ where
         }
 
         Ok(Some(PathInfo {
-            node: Some(castorepb::Node {
-                // set the name of the root node to the digest-name of the store path.
-                node: Some((&root_node.rename(narinfo.store_path.to_string().into())).into()),
-            }),
+            node: Some(castorepb::Node::from_name_and_node(
+                narinfo.store_path.to_string().into(),
+                root_node,
+            )),
             references: pathinfo.references,
             narinfo: pathinfo.narinfo,
         }))