refactor(tvix/castore): drop {Directory,File,Symlink}Node r/8505

Add a `SymlinkTarget` type to represent validated symlink targets.
With this, no invalid states are representable, so we can make `Node` be
just an enum of all three kind of types, and allow access to these
fields directly.

Change-Id: I20bdd480c8d5e64a827649f303c97023b7e390f2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12216
Reviewed-by: benjaminedwardwebb <benjaminedwardwebb@gmail.com>
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: Connor Brewster <cbrewster@hey.com>
Tested-by: BuildkiteCI

4 files changed, 64 insertions, 62 deletions

diff --git a/tvix/store/src/import.rs b/tvix/store/src/import.rs
index e279bb4c04c2..f2f38f538604 100644
--- a/tvix/store/src/import.rs
+++ b/tvix/store/src/import.rs
@@ -29,27 +29,27 @@ impl From<CAHash> for nar_info::Ca {
 
 pub fn log_node(name: &[u8], node: &Node, path: &Path) {
     match node {
-        Node::Directory(directory_node) => {
+        Node::Directory { digest, .. } => {
             debug!(
                 path = ?path,
                 name = %name.as_bstr(),
-                digest = %directory_node.digest(),
+                digest = %digest,
                 "import successful",
             )
         }
-        Node::File(file_node) => {
+        Node::File { digest, .. } => {
             debug!(
                 path = ?path,
                 name = %name.as_bstr(),
-                digest = %file_node.digest(),
+                digest = %digest,
                 "import successful"
             )
         }
-        Node::Symlink(symlink_node) => {
+        Node::Symlink { target } => {
             debug!(
                 path = ?path,
                 name = %name.as_bstr(),
-                target = ?symlink_node.target(),
+                target = ?target,
                 "import successful"
             )
         }
diff --git a/tvix/store/src/nar/import.rs b/tvix/store/src/nar/import.rs
index 71ab9bd588cd..b9a15fe71384 100644
--- a/tvix/store/src/nar/import.rs
+++ b/tvix/store/src/nar/import.rs
@@ -174,7 +174,7 @@ mod test {
         DIRECTORY_COMPLICATED, DIRECTORY_WITH_KEEP, EMPTY_BLOB_DIGEST, HELLOWORLD_BLOB_CONTENTS,
         HELLOWORLD_BLOB_DIGEST,
     };
-    use tvix_castore::{Directory, DirectoryNode, FileNode, Node, SymlinkNode};
+    use tvix_castore::{Directory, Node};
 
     use crate::tests::fixtures::{
         blob_service, directory_service, NAR_CONTENTS_COMPLICATED, NAR_CONTENTS_HELLOWORLD,
@@ -196,7 +196,9 @@ mod test {
         .expect("must parse");
 
         assert_eq!(
-            Node::Symlink(SymlinkNode::new("/nix/store/somewhereelse".into(),).unwrap()),
+            Node::Symlink {
+                target: "/nix/store/somewhereelse".try_into().unwrap()
+            },
             root_node
         );
     }
@@ -216,11 +218,11 @@ mod test {
         .expect("must parse");
 
         assert_eq!(
-            Node::File(FileNode::new(
-                HELLOWORLD_BLOB_DIGEST.clone(),
-                HELLOWORLD_BLOB_CONTENTS.len() as u64,
-                false,
-            )),
+            Node::File {
+                digest: HELLOWORLD_BLOB_DIGEST.clone(),
+                size: HELLOWORLD_BLOB_CONTENTS.len() as u64,
+                executable: false,
+            },
             root_node
         );
 
@@ -243,10 +245,10 @@ mod test {
         .expect("must parse");
 
         assert_eq!(
-            Node::Directory(DirectoryNode::new(
-                DIRECTORY_COMPLICATED.digest(),
-                DIRECTORY_COMPLICATED.size(),
-            )),
+            Node::Directory {
+                digest: DIRECTORY_COMPLICATED.digest(),
+                size: DIRECTORY_COMPLICATED.size()
+            },
             root_node,
         );
 
diff --git a/tvix/store/src/nar/renderer.rs b/tvix/store/src/nar/renderer.rs
index d83ef9c354f6..84c73c981cf0 100644
--- a/tvix/store/src/nar/renderer.rs
+++ b/tvix/store/src/nar/renderer.rs
@@ -82,7 +82,7 @@ where
 /// The contents in NAR serialization are writen to the passed [AsyncWrite].
 pub async fn write_nar<W, BS, DS>(
     mut w: W,
-    proto_root_node: &Node,
+    root_node: &Node,
     blob_service: BS,
     directory_service: DS,
 ) -> Result<(), RenderError>
@@ -98,7 +98,7 @@ where
 
     walk_node(
         nar_root_node,
-        proto_root_node,
+        root_node,
         b"",
         blob_service,
         directory_service,
@@ -122,15 +122,17 @@ where
     DS: DirectoryService + Send,
 {
     match castore_node {
-        Node::Symlink(symlink_node) => {
+        Node::Symlink { target, .. } => {
             nar_node
-                .symlink(symlink_node.target())
+                .symlink(target.as_ref())
                 .await
                 .map_err(RenderError::NARWriterError)?;
         }
-        Node::File(proto_file_node) => {
-            let digest = proto_file_node.digest();
-
+        Node::File {
+            digest,
+            size,
+            executable,
+        } => {
             let mut blob_reader = match blob_service
                 .open_read(digest)
                 .await
@@ -144,24 +146,20 @@ where
             }?;
 
             nar_node
-                .file(
-                    proto_file_node.executable(),
-                    proto_file_node.size(),
-                    &mut blob_reader,
-                )
+                .file(*executable, *size, &mut blob_reader)
                 .await
                 .map_err(RenderError::NARWriterError)?;
         }
-        Node::Directory(directory_node) => {
+        Node::Directory { digest, .. } => {
             // look it up with the directory service
             match directory_service
-                .get(directory_node.digest())
+                .get(digest)
                 .await
                 .map_err(|e| RenderError::StoreError(e.into()))?
             {
                 // if it's None, that's an error!
                 None => Err(RenderError::DirectoryNotFound(
-                    directory_node.digest().clone(),
+                    digest.clone(),
                     bytes::Bytes::copy_from_slice(name),
                 ))?,
                 Some(directory) => {
diff --git a/tvix/store/src/tests/nar_renderer.rs b/tvix/store/src/tests/nar_renderer.rs
index fafcaf39e1e7..03eaa28aaac8 100644
--- a/tvix/store/src/tests/nar_renderer.rs
+++ b/tvix/store/src/tests/nar_renderer.rs
@@ -10,7 +10,7 @@ use std::sync::Arc;
 use tokio::io::sink;
 use tvix_castore::blobservice::BlobService;
 use tvix_castore::directoryservice::DirectoryService;
-use tvix_castore::{DirectoryNode, FileNode, Node, SymlinkNode};
+use tvix_castore::Node;
 
 #[rstest]
 #[tokio::test]
@@ -22,7 +22,9 @@ async fn single_symlink(
 
     write_nar(
         &mut buf,
-        &Node::Symlink(SymlinkNode::new("/nix/store/somewhereelse".into()).unwrap()),
+        &Node::Symlink {
+            target: "/nix/store/somewhereelse".try_into().unwrap(),
+        },
         // don't put anything in the stores, as we don't actually do any requests.
         blob_service,
         directory_service,
@@ -42,11 +44,11 @@ async fn single_file_missing_blob(
 ) {
     let e = write_nar(
         sink(),
-        &Node::File(FileNode::new(
-            HELLOWORLD_BLOB_DIGEST.clone(),
-            HELLOWORLD_BLOB_CONTENTS.len() as u64,
-            false,
-        )),
+        &Node::File {
+            digest: HELLOWORLD_BLOB_DIGEST.clone(),
+            size: HELLOWORLD_BLOB_CONTENTS.len() as u64,
+            executable: false,
+        },
         // the blobservice is empty intentionally, to provoke the error.
         blob_service,
         directory_service,
@@ -86,11 +88,11 @@ async fn single_file_wrong_blob_size(
     // Test with a root FileNode of a too big size
     let e = write_nar(
         sink(),
-        &Node::File(FileNode::new(
-            HELLOWORLD_BLOB_DIGEST.clone(),
-            42, // <- note the wrong size here!
-            false,
-        )),
+        &Node::File {
+            digest: HELLOWORLD_BLOB_DIGEST.clone(),
+            size: 42, // <- note the wrong size here!
+            executable: false,
+        },
         blob_service.clone(),
         directory_service.clone(),
     )
@@ -107,11 +109,11 @@ async fn single_file_wrong_blob_size(
     // Test with a root FileNode of a too small size
     let e = write_nar(
         sink(),
-        &Node::File(FileNode::new(
-            HELLOWORLD_BLOB_DIGEST.clone(),
-            2, // <- note the wrong size here!
-            false,
-        )),
+        &Node::File {
+            digest: HELLOWORLD_BLOB_DIGEST.clone(),
+            size: 2, // <- note the wrong size here!
+            executable: false,
+        },
         blob_service,
         directory_service,
     )
@@ -147,11 +149,11 @@ async fn single_file(
 
     write_nar(
         &mut buf,
-        &Node::File(FileNode::new(
-            HELLOWORLD_BLOB_DIGEST.clone(),
-            HELLOWORLD_BLOB_CONTENTS.len() as u64,
-            false,
-        )),
+        &Node::File {
+            digest: HELLOWORLD_BLOB_DIGEST.clone(),
+            size: HELLOWORLD_BLOB_CONTENTS.len() as u64,
+            executable: false,
+        },
         blob_service,
         directory_service,
     )
@@ -189,10 +191,10 @@ async fn test_complicated(
 
     write_nar(
         &mut buf,
-        &Node::Directory(DirectoryNode::new(
-            DIRECTORY_COMPLICATED.digest(),
-            DIRECTORY_COMPLICATED.size(),
-        )),
+        &Node::Directory {
+            digest: DIRECTORY_COMPLICATED.digest(),
+            size: DIRECTORY_COMPLICATED.size(),
+        },
         blob_service.clone(),
         directory_service.clone(),
     )
@@ -203,10 +205,10 @@ async fn test_complicated(
 
     // ensure calculate_nar does return the correct sha256 digest and sum.
     let (nar_size, nar_digest) = calculate_size_and_sha256(
-        &Node::Directory(DirectoryNode::new(
-            DIRECTORY_COMPLICATED.digest(),
-            DIRECTORY_COMPLICATED.size(),
-        )),
+        &Node::Directory {
+            digest: DIRECTORY_COMPLICATED.digest(),
+            size: DIRECTORY_COMPLICATED.size(),
+        },
         blob_service,
         directory_service,
     )