Choose appropriate datastructures for references

wnfs-wg · Aug 25, 2023 · b3c51ae · b3c51ae
1 parent cad84c8
commit b3c51ae
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Showing 4 changed files with 5 additions and 6 deletions.
diff --git a/car-mirror/src/common.rs b/car-mirror/src/common.rs
@@ -207,13 +207,12 @@ pub async fn block_receive(
 /// This will error out if
 /// - the codec is not supported
 /// - the block can't be parsed.
-pub fn references(cid: Cid, block: impl AsRef<[u8]>) -> Result<Vec<Cid>> {
+pub fn references<E: Extend<Cid>>(cid: Cid, block: impl AsRef<[u8]>, mut refs: E) -> Result<E> {
     let codec: IpldCodec = cid
         .codec()
         .try_into()
         .map_err(|_| anyhow!("Unsupported codec in Cid: {cid}"))?;
 
-    let mut refs = Vec::new();
     <Ipld as References<IpldCodec>>::references(codec, &mut Cursor::new(block), &mut refs)?;
     Ok(refs)
 }

diff --git a/car-mirror/src/dag_walk.rs b/car-mirror/src/dag_walk.rs
@@ -76,7 +76,7 @@ impl DagWalk {
         // - skip Raw CIDs. They can't have further links (but needs adjustment to this function's return type)
         // - run multiple `get_block` calls concurrently
         let block = store.get_block(&cid).await?;
-        for ref_cid in references(cid, &block)? {
+        for ref_cid in references(cid, &block, HashSet::new())? {
             if !self.visited.contains(&ref_cid) {
                 self.frontier.push_front(ref_cid);
             }
@@ -112,7 +112,7 @@ impl DagWalk {
     /// Skip a node from the traversal for now.
     pub fn skip_walking(&mut self, block: (Cid, Bytes)) -> Result<()> {
         let (cid, bytes) = block;
-        let refs = references(cid, bytes)?;
+        let refs = references(cid, bytes, HashSet::new())?;
         self.visited.insert(cid);
         self.frontier
             .retain(|frontier_cid| !refs.contains(frontier_cid));

diff --git a/car-mirror/src/test_utils/blockstore_utils.rs b/car-mirror/src/test_utils/blockstore_utils.rs
@@ -37,7 +37,7 @@ pub fn dag_to_dot(
 
     for (cid, ipld) in blocks {
         let bytes = encode(&ipld)?;
-        let refs = references(cid, bytes)?;
+        let refs = references(cid, bytes, Vec::new())?;
         for to_cid in refs {
             print_truncated_string(writer, cid.to_string())?;
             write!(writer, " -> ")?;

diff --git a/car-mirror/src/test_utils/local_utils.rs b/car-mirror/src/test_utils/local_utils.rs
@@ -24,7 +24,7 @@ pub(crate) async fn get_cid_at_approx_path(
     let mut working_cid = root;
     for nth in path {
         let block = store.get_block(&working_cid).await?;
-        let refs = references(working_cid, block)?;
+        let refs = references(working_cid, block, Vec::new())?;
         if refs.is_empty() {
             break;
         }