feat(tvix/castore/directory/traverse): use castore Paths r/8066

This switches from using std::path::Path to using castore paths.

We can drop some error handling in descend_to, as absolute (or redundant)
paths are not representable.

We however now need to convert from a std::path::Path to our
representation, and decide to accept .. canonicalization, as paths in
EvalIO might contain this. Dealing .. to hop into another store path, if
we encounter this, should be dealt with in a previous step.

Change-Id: I5e94693808420c5d56587c68731252b54755bf93
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11575
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: Connor Brewster <cbrewster@hey.com>
Tested-by: BuildkiteCI

2 files changed, 17 insertions, 52 deletions

diff --git a/tvix/castore/src/directoryservice/traverse.rs b/tvix/castore/src/directoryservice/traverse.rs
index 573581edbd..8a668c868c 100644
--- a/tvix/castore/src/directoryservice/traverse.rs
+++ b/tvix/castore/src/directoryservice/traverse.rs
@@ -1,30 +1,20 @@
 use super::DirectoryService;
-use crate::{proto::NamedNode, B3Digest, Error};
-use std::os::unix::ffi::OsStrExt;
+use crate::{proto::NamedNode, B3Digest, Error, Path};
 use tracing::{instrument, warn};
 
 /// This descends from a (root) node to the given (sub)path, returning the Node
 /// at that path, or none, if there's nothing at that path.
-#[instrument(skip(directory_service))]
+#[instrument(skip(directory_service, path), fields(%path))]
 pub async fn descend_to<DS>(
     directory_service: DS,
     root_node: crate::proto::node::Node,
-    path: &std::path::Path,
+    path: impl AsRef<Path> + std::fmt::Display,
 ) -> Result<Option<crate::proto::node::Node>, Error>
 where
     DS: AsRef<dyn DirectoryService>,
 {
-    // strip a possible `/` prefix from the path.
-    let path = {
-        if path.starts_with("/") {
-            path.strip_prefix("/").unwrap()
-        } else {
-            path
-        }
-    };
-
     let mut cur_node = root_node;
-    let mut it = path.components();
+    let mut it = path.as_ref().components();
 
     loop {
         match it.next() {
@@ -59,9 +49,8 @@ where
                                 // look for first_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.
-                                let child_node = directory.nodes().find(|n| {
-                                    n.get_name() == first_component.as_os_str().as_bytes()
-                                });
+                                let child_node =
+                                    directory.nodes().find(|n| n.get_name() == first_component);
 
                                 match child_node {
                                     // child node not found means there's no such element inside the directory.
@@ -85,11 +74,10 @@ where
 
 #[cfg(test)]
 mod tests {
-    use std::path::PathBuf;
-
     use crate::{
         directoryservice,
         fixtures::{DIRECTORY_COMPLICATED, DIRECTORY_WITH_KEEP},
+        PathBuf,
     };
 
     use super::descend_to;
@@ -132,7 +120,7 @@ mod tests {
             let resp = descend_to(
                 &directory_service,
                 node_directory_complicated.clone(),
-                &PathBuf::from(""),
+                "".parse::<PathBuf>().unwrap(),
             )
             .await
             .expect("must succeed");
@@ -145,7 +133,7 @@ mod tests {
             let resp = descend_to(
                 &directory_service,
                 node_directory_complicated.clone(),
-                &PathBuf::from("keep"),
+                "keep".parse::<PathBuf>().unwrap(),
             )
             .await
             .expect("must succeed");
@@ -158,7 +146,7 @@ mod tests {
             let resp = descend_to(
                 &directory_service,
                 node_directory_complicated.clone(),
-                &PathBuf::from("keep/.keep"),
+                "keep/.keep".parse::<PathBuf>().unwrap(),
             )
             .await
             .expect("must succeed");
@@ -166,25 +154,12 @@ mod tests {
             assert_eq!(Some(node_file_keep.clone()), resp);
         }
 
-        // traversal to `keep/.keep` should return the node for the .keep file
-        {
-            let resp = descend_to(
-                &directory_service,
-                node_directory_complicated.clone(),
-                &PathBuf::from("/keep/.keep"),
-            )
-            .await
-            .expect("must succeed");
-
-            assert_eq!(Some(node_file_keep), resp);
-        }
-
         // traversal to `void` should return None (doesn't exist)
         {
             let resp = descend_to(
                 &directory_service,
                 node_directory_complicated.clone(),
-                &PathBuf::from("void"),
+                "void".parse::<PathBuf>().unwrap(),
             )
             .await
             .expect("must succeed");
@@ -192,12 +167,12 @@ mod tests {
             assert_eq!(None, resp);
         }
 
-        // traversal to `void` should return None (doesn't exist)
+        // traversal to `v/oid` should return None (doesn't exist)
         {
             let resp = descend_to(
                 &directory_service,
                 node_directory_complicated.clone(),
-                &PathBuf::from("//v/oid"),
+                "v/oid".parse::<PathBuf>().unwrap(),
             )
             .await
             .expect("must succeed");
@@ -211,25 +186,12 @@ mod tests {
             let resp = descend_to(
                 &directory_service,
                 node_directory_complicated.clone(),
-                &PathBuf::from("keep/.keep/foo"),
+                "keep/.keep/foo".parse::<PathBuf>().unwrap(),
             )
             .await
             .expect("must succeed");
 
             assert_eq!(None, resp);
         }
-
-        // traversal to a subpath of '/' should return the root node.
-        {
-            let resp = descend_to(
-                &directory_service,
-                node_directory_complicated.clone(),
-                &PathBuf::from("/"),
-            )
-            .await
-            .expect("must succeed");
-
-            assert_eq!(Some(node_directory_complicated), resp);
-        }
     }
 }
diff --git a/tvix/glue/src/tvix_store_io.rs b/tvix/glue/src/tvix_store_io.rs
index 1f709906de..7daefffe82 100644
--- a/tvix/glue/src/tvix_store_io.rs
+++ b/tvix/glue/src/tvix_store_io.rs
@@ -305,6 +305,9 @@ impl TvixStoreIO {
         };
 
         // now with the root_node and sub_path, descend to the node requested.
+        // We convert sub_path to the castore model here.
+        let sub_path = tvix_castore::PathBuf::from_host_path(sub_path, true)?;
+
         directoryservice::descend_to(&self.directory_service, root_node, sub_path)
             .await
             .map_err(|e| std::io::Error::new(io::ErrorKind::Other, e))