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, 2 insertions, 51 deletions

diff --git a/tvix/castore/src/nodes/mod.rs b/tvix/castore/src/nodes/mod.rs
index bb8e14cf856e..47f39ae8f94a 100644
--- a/tvix/castore/src/nodes/mod.rs
+++ b/tvix/castore/src/nodes/mod.rs
@@ -4,66 +4,17 @@ mod directory_node;
 mod file_node;
 mod symlink_node;
 
-use bytes::Bytes;
 pub use directory::Directory;
 pub use directory_node::DirectoryNode;
 pub use file_node::FileNode;
 pub use symlink_node::SymlinkNode;
 
 /// A Node is either a [DirectoryNode], [FileNode] or [SymlinkNode].
-/// While a Node by itself may have any name, only those matching specific requirements
-/// can can be added as entries to a [Directory] (see the documentation on [Directory] for details).
+/// Nodes themselves don't have names, what gives them names is either them
+/// being inside a [Directory], or a root node with its own name attached to it.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Node {
     Directory(DirectoryNode),
     File(FileNode),
     Symlink(SymlinkNode),
 }
-
-impl Node {
-    /// Returns the node with a new name.
-    pub fn rename(self, name: Bytes) -> Self {
-        match self {
-            Node::Directory(n) => Node::Directory(n.rename(name)),
-            Node::File(n) => Node::File(n.rename(name)),
-            Node::Symlink(n) => Node::Symlink(n.rename(name)),
-        }
-    }
-}
-
-impl PartialOrd for Node {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-impl Ord for Node {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.get_name().cmp(other.get_name())
-    }
-}
-
-/// NamedNode is implemented for [FileNode], [DirectoryNode] and [SymlinkNode]
-/// and [Node], so we can ask all of them for the name easily.
-pub trait NamedNode {
-    fn get_name(&self) -> &Bytes;
-}
-
-impl NamedNode for &Node {
-    fn get_name(&self) -> &Bytes {
-        match self {
-            Node::File(node_file) => node_file.get_name(),
-            Node::Directory(node_directory) => node_directory.get_name(),
-            Node::Symlink(node_symlink) => node_symlink.get_name(),
-        }
-    }
-}
-impl NamedNode for Node {
-    fn get_name(&self) -> &Bytes {
-        match self {
-            Node::File(node_file) => node_file.get_name(),
-            Node::Directory(node_directory) => node_directory.get_name(),
-            Node::Symlink(node_symlink) => node_symlink.get_name(),
-        }
-    }
-}