do add/sub lt hash

accounts-db/src/accounts_db.rs

@@ -7979,8 +7979,12 @@ impl AccountsDb {
             HashMap<Pubkey, (Option<AccountSharedData>, Option<AccountLTHash>)>,
         >,
     ) {
-        // we are assuming it was easy to lookup a hash for everything written in `slot` when we were calculating the delta hash. So, caller passes in `pubkey_hash`
-        // note we don't need rewrites in `pubkey_hash`. these accounts had the same hash before and after. So, we only have to consider what was written that changed.
+        // We are assuming it was easy to lookup a hash for everything written
+        // in `slot` when we were calculating the delta hash. So, caller passes
+        // in `pubkey_hash`. Note we don't need rewrites in `pubkey_hash`. these
+        // accounts had the same hash before and after. So, we only have to
+        // consider what was written that changed.
+        let curr_ancestor = ancestors.clone();
         ancestors.remove(&slot);
         let old_written_accounts = old_written_accounts.read().unwrap();
         // if we want to look it up ourselves: let (hashes, _scan_us, _accumulate) = self.get_pubkey_hash_for_slot(slot);
@@ -7995,15 +7999,19 @@ impl AccountsDb {
                 }
             })
             .collect::<Vec<_>>();
+
         pubkey_hash
             .into_iter()
             .zip(old.into_iter())
-            .for_each(|((k, new_hash), old_hash)| {
+            .for_each(|((k, _new_hash), old_hash)| {
                 if let Some(old) = old_hash {
                     // todo if old == new, then we can avoid this update altogether
-                    // todo subtract accumulated_accounts_hash -= old_hash
+                    accumulated_accounts_hash.sub(&old);
                 }
-                // todo add accumulated_accounts_hash += new_hash
+                let new = self
+                    .load_with_fixed_root(&curr_ancestors, &k)
+                    .map(|(account, _)| Self::lt_hash_account(&account, &k));
+                accumulated_accounts_hash.add(&new);
             });
     }