refactor(tvix/castore): use Directory struct separate from proto one r/8484

This uses our own data type to deal with Directories in the castore model.

It makes some undesired states unrepresentable, removing the need for conversions and checking in various places:

 - In the protobuf, blake3 digests could have a wrong length, as proto doesn't know fixed-size fields. We now use `B3Digest`, which makes cloning cheaper, and removes the need to do size-checking everywhere.
 - In the protobuf, we had three different lists for `files`, `symlinks` and `directories`. This was mostly a protobuf size optimization, but made interacting with them a bit awkward. This has now been replaced with a list of enums, and convenience iterators to get various nodes, and add new ones.

Change-Id: I7b92691bb06d77ff3f58a5ccea94a22c16f84f04
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12057
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 4 insertions, 5 deletions

diff --git a/tvix/castore/src/directoryservice/combinators.rs b/tvix/castore/src/directoryservice/combinators.rs
index 0fdc82c16cb0..4283142231f9 100644
--- a/tvix/castore/src/directoryservice/combinators.rs
+++ b/tvix/castore/src/directoryservice/combinators.rs
@@ -7,10 +7,9 @@ use futures::TryStreamExt;
 use tonic::async_trait;
 use tracing::{instrument, trace};
 
-use super::{DirectoryGraph, DirectoryService, RootToLeavesValidator, SimplePutter};
+use super::{Directory, DirectoryGraph, DirectoryService, RootToLeavesValidator, SimplePutter};
 use crate::composition::{CompositionContext, ServiceBuilder};
 use crate::directoryservice::DirectoryPutter;
-use crate::proto;
 use crate::B3Digest;
 use crate::Error;
 
@@ -40,7 +39,7 @@ where
     DS2: DirectoryService + Clone + 'static,
 {
     #[instrument(skip(self, digest), fields(directory.digest = %digest))]
-    async fn get(&self, digest: &B3Digest) -> Result<Option<proto::Directory>, Error> {
+    async fn get(&self, digest: &B3Digest) -> Result<Option<Directory>, Error> {
         match self.near.get(digest).await? {
             Some(directory) => {
                 trace!("serving from cache");
@@ -82,7 +81,7 @@ where
     }
 
     #[instrument(skip_all)]
-    async fn put(&self, _directory: proto::Directory) -> Result<B3Digest, Error> {
+    async fn put(&self, _directory: Directory) -> Result<B3Digest, Error> {
         Err(Error::StorageError("unimplemented".to_string()))
     }
 
@@ -90,7 +89,7 @@ where
     fn get_recursive(
         &self,
         root_directory_digest: &B3Digest,
-    ) -> BoxStream<'static, Result<proto::Directory, Error>> {
+    ) -> BoxStream<'static, Result<Directory, Error>> {
         let near = self.near.clone();
         let far = self.far.clone();
         let digest = root_directory_digest.clone();