feat(trie): SparseStateTrie::update_account (#12954)

crates/trie/common/src/constants.rs

@@ -0,0 +1,24 @@
+/// The maximum size of RLP encoded trie account in bytes.
+/// 2 (header) + 4 * 1 (field lens) + 8 (nonce) + 32 * 3 (balance, storage root, code hash)
+pub const TRIE_ACCOUNT_RLP_MAX_SIZE: usize = 110;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::TrieAccount;
+    use alloy_primitives::{B256, U256};
+    use alloy_rlp::Encodable;
+
+    #[test]
+    fn account_rlp_max_size() {
+        let account = TrieAccount {
+            nonce: u64::MAX,
+            balance: U256::MAX,
+            storage_root: B256::from_slice(&[u8::MAX; 32]),
+            code_hash: B256::from_slice(&[u8::MAX; 32]),
+        };
+        let mut encoded = Vec::new();
+        account.encode(&mut encoded);
+        assert_eq!(encoded.len(), TRIE_ACCOUNT_RLP_MAX_SIZE);
+    }
+}

crates/trie/common/src/lib.rs

@@ -11,6 +11,10 @@
 /// The implementation of hash builder.
 pub mod hash_builder;
 
+/// Constants related to the trie computation.
+mod constants;
+pub use constants::*;
+
 mod account;
 pub use account::TrieAccount;