feat: add block root slot index

crates/net/p2p/src/req_resp/handlers.rs

@@ -1,4 +1,4 @@
-use std::collections::{HashMap, HashSet};
+use std::collections::HashSet;
 
 use ethlambda_storage::Store;
 use libp2p::{PeerId, request_response};
@@ -269,29 +269,10 @@ fn canonical_blocks_by_range(store: &Store, start_slot: u64, count: u64) -> Vec<
         return Vec::new();
     };
 
-    let mut roots_by_slot = HashMap::new();
-    let mut current_root = store.head().expect("head block exists");
-
-    while !current_root.is_zero() {
-        let Ok(Some(header)) = store.get_block_header(&current_root) else {
-            break;
-        };
-
-        if header.slot < start_slot {
-            break;
-        }
-
-        if header.slot <= end_slot {
-            roots_by_slot.insert(header.slot, current_root);
-        }
-
-        current_root = header.parent_root;
-    }
-
     (start_slot..=end_slot)
         .filter_map(|slot| {
-            let root = roots_by_slot.get(&slot)?;
-            store.get_signed_block(root).ok().flatten()
+            let root = store.get_block_root_by_slot(slot)?;
+            store.get_signed_block(&root).ok().flatten()
         })
         .collect()
 }

crates/storage/src/api/tables.rs

@@ -10,6 +10,8 @@ pub enum Table {
     /// Stored separately from blocks because the genesis block has no signatures.
     /// All other blocks must have an entry in this table.
     BlockSignatures,
+    /// Canonical block index: slot -> block root
+    BlockRoots,
     /// State storage: H256 -> State
     ///
     /// Holds full-state snapshots only: the bootstrap anchor plus one anchor per
@@ -32,10 +34,11 @@ pub enum Table {
 }
 
 /// All table variants.
-pub const ALL_TABLES: [Table; 7] = [
+pub const ALL_TABLES: [Table; 8] = [
     Table::BlockHeaders,
     Table::BlockBodies,
     Table::BlockSignatures,
+    Table::BlockRoots,
     Table::States,
     Table::StateDiffs,
     Table::Metadata,
@@ -49,6 +52,7 @@ impl Table {
             Table::BlockHeaders => "block_headers",
             Table::BlockBodies => "block_bodies",
             Table::BlockSignatures => "block_signatures",
+            Table::BlockRoots => "block_roots",
             Table::States => "states",
             Table::StateDiffs => "state_diffs",
             Table::Metadata => "metadata",