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>

1 files changed, 18 insertions, 15 deletions

diff --git a/tvix/castore/src/directoryservice/traverse.rs b/tvix/castore/src/directoryservice/traverse.rs
index ff667e0f65c0..de2ea33c7f9d 100644
--- a/tvix/castore/src/directoryservice/traverse.rs
+++ b/tvix/castore/src/directoryservice/traverse.rs
@@ -1,4 +1,4 @@
-use crate::{directoryservice::DirectoryService, Error, NamedNode, Node, Path};
+use crate::{directoryservice::DirectoryService, Error, Node, Path};
 use tracing::{instrument, warn};
 
 /// This descends from a (root) node to the given (sub)path, returning the Node
@@ -37,9 +37,10 @@ where
                     })?;
 
                 // look for the component in the [Directory].
-                // FUTUREWORK: as the nodes() iterator returns in a sorted fashion, we
-                // could stop as soon as e.name is larger than the search string.
-                if let Some(child_node) = directory.nodes().find(|n| n.get_name() == component) {
+                if let Some((_child_name, child_node)) = directory
+                    .nodes()
+                    .find(|(name, _node)| name.as_ref() == component)
+                {
                     // child node found, update prev_node to that and continue.
                     parent_node = child_node.clone();
                 } else {
@@ -81,21 +82,23 @@ mod tests {
         handle.close().await.expect("must upload");
 
         // construct the node for DIRECTORY_COMPLICATED
-        let node_directory_complicated = Node::Directory(
-            DirectoryNode::new(
-                "doesntmatter".into(),
-                DIRECTORY_COMPLICATED.digest(),
-                DIRECTORY_COMPLICATED.size(),
-            )
-            .unwrap(),
-        );
+        let node_directory_complicated = Node::Directory(DirectoryNode::new(
+            DIRECTORY_COMPLICATED.digest(),
+            DIRECTORY_COMPLICATED.size(),
+        ));
 
         // construct the node for DIRECTORY_COMPLICATED
-        let node_directory_with_keep =
-            Node::Directory(DIRECTORY_COMPLICATED.directories().next().unwrap().clone());
+        let node_directory_with_keep = Node::Directory(
+            DIRECTORY_COMPLICATED
+                .directories()
+                .next()
+                .unwrap()
+                .1
+                .clone(),
+        );
 
         // construct the node for the .keep file
-        let node_file_keep = Node::File(DIRECTORY_WITH_KEEP.files().next().unwrap().clone());
+        let node_file_keep = Node::File(DIRECTORY_WITH_KEEP.files().next().unwrap().1.clone());
 
         // traversal to an empty subpath should return the root node.
         {