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, 9 insertions, 11 deletions

diff --git a/tvix/castore/src/fs/mod.rs b/tvix/castore/src/fs/mod.rs
index b565ed60ac42..4a6ca88d73fd 100644
--- a/tvix/castore/src/fs/mod.rs
+++ b/tvix/castore/src/fs/mod.rs
@@ -15,11 +15,9 @@ use self::{
     inode_tracker::InodeTracker,
     inodes::{DirectoryInodeData, InodeData},
 };
-use crate::proto as castorepb;
 use crate::{
     blobservice::{BlobReader, BlobService},
-    directoryservice::DirectoryService,
-    proto::{node::Node, NamedNode},
+    directoryservice::{DirectoryService, NamedNode, Node},
     B3Digest,
 };
 use bstr::ByteVec;
@@ -198,13 +196,13 @@ where
                 let children = {
                     let mut inode_tracker = self.inode_tracker.write();
 
-                    let children: Vec<(u64, castorepb::node::Node)> = directory
+                    let children: Vec<(u64, Node)> = directory
                         .nodes()
                         .map(|child_node| {
-                            let (inode_data, _) = InodeData::from_node(child_node.clone());
+                            let (inode_data, _) = InodeData::from_node(child_node);
 
                             let child_ino = inode_tracker.put(inode_data);
-                            (child_ino, child_node)
+                            (child_ino, child_node.clone())
                         })
                         .collect();
 
@@ -287,7 +285,7 @@ where
 
                 // insert the (sparse) inode data and register in
                 // self.root_nodes.
-                let (inode_data, name) = InodeData::from_node(root_node);
+                let (inode_data, name) = InodeData::from_node(&root_node);
                 let ino = inode_tracker.put(inode_data.clone());
                 root_nodes.insert(name, ino);
 
@@ -468,7 +466,7 @@ where
                     io::Error::from_raw_os_error(libc::EIO)
                 })?;
 
-                let (inode_data, name) = InodeData::from_node(root_node);
+                let (inode_data, name) = InodeData::from_node(&root_node);
 
                 // obtain the inode, or allocate a new one.
                 let ino = self.get_inode_for_root_name(&name).unwrap_or_else(|| {
@@ -498,7 +496,7 @@ where
         Span::current().record("directory.digest", parent_digest.to_string());
 
         for (i, (ino, child_node)) in children.into_iter().skip(offset as usize).enumerate() {
-            let (inode_data, name) = InodeData::from_node(child_node);
+            let (inode_data, name) = InodeData::from_node(&child_node);
 
             // the second parameter will become the "offset" parameter on the next call.
             let written = add_entry(fuse_backend_rs::api::filesystem::DirEntry {
@@ -555,7 +553,7 @@ where
                     io::Error::from_raw_os_error(libc::EPERM)
                 })?;
 
-                let (inode_data, name) = InodeData::from_node(root_node);
+                let (inode_data, name) = InodeData::from_node(&root_node);
 
                 // obtain the inode, or allocate a new one.
                 let ino = self.get_inode_for_root_name(&name).unwrap_or_else(|| {
@@ -588,7 +586,7 @@ where
         Span::current().record("directory.digest", parent_digest.to_string());
 
         for (i, (ino, child_node)) in children.into_iter().skip(offset as usize).enumerate() {
-            let (inode_data, name) = InodeData::from_node(child_node);
+            let (inode_data, name) = InodeData::from_node(&child_node);
 
             // the second parameter will become the "offset" parameter on the next call.
             let written = add_entry(