feat: add block_body_indices for BlockchainProvider2

crates/chain-state/src/in_memory.rs

@@ -207,7 +207,7 @@ impl CanonicalInMemoryState {
         Self { inner: Arc::new(inner) }
     }
 
-    /// Returns the block hash corresponding to the given number
+    /// Returns the block hash corresponding to the given number.
     pub fn hash_by_number(&self, number: u64) -> Option<B256> {
         self.inner.in_memory_state.hash_by_number(number)
     }

crates/storage/errors/src/provider.rs

@@ -100,8 +100,11 @@ pub enum ProviderError {
     #[error("unknown block {0}")]
     UnknownBlockHash(B256),
     /// Thrown when we were unable to find a state for a block hash.
-    #[error("no state found for block {0}")]
+    #[error("no state found for block hash {0}")]
     StateForHashNotFound(B256),
+    /// Thrown when we were unable to find a state for a block number.
+    #[error("no state found for block number {0}")]
+    StateForNumberNotFound(u64),
     /// Unable to find the block number for a given transaction index.
     #[error("unable to find the block number for a given transaction index")]
     BlockNumberForTransactionIndexNotFound,

crates/storage/provider/src/providers/blockchain_provider.rs

@@ -428,7 +428,33 @@ where
         &self,
         number: BlockNumber,
     ) -> ProviderResult<Option<StoredBlockBodyIndices>> {
-        self.database.block_body_indices(number)
+        if let Some(indices) = self.database.block_body_indices(number)? {
+            Ok(Some(indices))
+        } else if let Some(state) = self.canonical_in_memory_state.state_by_number(number) {
+            // we have to construct the stored indices for the in memory blocks
+            //
+            // To calculate this we will fetch the anchor block and walk forward from all parents
+            let mut parent_chain = state.parent_state_chain();
+            parent_chain.reverse();
+            let anchor_num = state.anchor().number;
+            let mut stored_indices = self
+                .database
+                .block_body_indices(anchor_num)?
+                .ok_or_else(|| ProviderError::BlockBodyIndicesNotFound(anchor_num))?;
+
+            for state in parent_chain {
+                let txs = state.block().block.body.len() as u64;
+                if state.block().block().number == number {
+                    stored_indices.tx_count = txs;
+                } else {
+                    stored_indices.first_tx_num += txs;
+                }
+            }
+
+            Ok(Some(stored_indices))
+        } else {
+            Ok(None)
+        }
     }
 
     /// Returns the block with senders with matching number or hash from database.