feature: beacon sidecar iterator

crates/rpc-types-beacon/src/sidecar.rs

@@ -1,15 +1,60 @@
 use crate::header::Header;
-use alloy_eips::eip4844::{Blob, Bytes48};
+use alloy_eips::eip4844::{Blob, BlobTransactionSidecar, Bytes48};
 use alloy_primitives::{Bytes, B256};
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, DisplayFromStr};
+use std::vec::IntoIter;
 
 /// Bundle of blobs for a given block
 #[serde_as]
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct BeaconBlobBundle {
     /// Vec of individual blob data
-    pub data: Vec<BlobData>,
+    data: Vec<BlobData>,
+}
+
+/// Yields an iterator for BlobData
+impl IntoIterator for BeaconBlobBundle {
+    type Item = BlobData;
+    type IntoIter = IntoIter<BlobData>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.data.into_iter()
+    }
+}
+
+/// Intermediate type for BlobTransactionSidecar matching
+#[derive(Debug, Clone)]
+pub struct SidecarIterator {
+    pub iter: IntoIter<BlobData>,
+}
+
+impl Iterator for SidecarIterator {
+    type Item = BlobData;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}
+
+impl SidecarIterator {
+    pub fn new(bundle: BeaconBlobBundle) -> Self {
+        SidecarIterator { iter: bundle.into_iter() }
+    }
+
+    /// Returns a BlobTransactionSidecar of len num_hashes.
+    pub fn next_sidecar(&mut self, num_hashes: usize) -> Option<BlobTransactionSidecar> {
+        let mut blobs = Vec::with_capacity(num_hashes);
+        let mut commitments = Vec::with_capacity(num_hashes);
+        let mut proofs = Vec::with_capacity(num_hashes);
+        for _ in 0..num_hashes {
+            let next = self.next()?;
+            blobs.push(*next.blob);
+            commitments.push(next.kzg_commitment);
+            proofs.push(next.kzg_proof);
+        }
+        Some(BlobTransactionSidecar { blobs, commitments, proofs })
+    }
 }
 
 /// Individual Blob data that belongs to a 4844 transaction.
@@ -32,7 +77,7 @@ pub struct BlobData {
     pub kzg_commitment_inclusion_proof: Vec<B256>,
 }
 
-// Helper function to deserialize boxed blobs
+/// Helper function to deserialize boxed blobs
 fn deserialize_blob<'de, D>(deserializer: D) -> Result<Box<Blob>, D::Error>
 where
     D: serde::de::Deserializer<'de>,
@@ -48,7 +93,7 @@ where
 mod tests {
     use super::*;
 
-    // Should deserialise json containing 6 blobs
+    /// Should deserialise json containing 6 blobs
     #[test]
     fn serde_sidecar_bundle() {
         let s = include_str!("examples/sidecar.json");