Cleaned state root commitments crate (#132)

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Next release
 
+- fix(root): Cleaned state root commitments crate
 - fix(hash): declare tx v0 hash computation
 - perf(db): db contract history parallel fetching and batching
 - remove RuntimeApi on RPC

crates/client/sync/src/commitments/classes.rs

@@ -0,0 +1,58 @@
+use blockifier::state::cached_state::CommitmentStateDiff;
+use mc_db::storage_handler::{self, DeoxysStorageError};
+use mp_felt::Felt252Wrapper;
+use mp_hashers::poseidon::PoseidonHasher;
+use mp_hashers::HasherT;
+use rayon::prelude::*;
+use starknet_ff::FieldElement;
+
+// "CONTRACT_CLASS_LEAF_V0"
+const CONTRACT_CLASS_HASH_VERSION: FieldElement =
+    FieldElement::from_mont([9331882290187415277, 12057587991035439952, 18444375821049509847, 115292049744600508]);
+
+/// Calculates the class trie root
+///
+/// # Arguments
+///
+/// * `csd`          - Commitment state diff for the current block.
+/// * `bonsai_class` - Bonsai db used to store class hashes.
+/// * `block_number` - The current block number.
+///
+/// # Returns
+///
+/// The class root.
+pub fn class_trie_root(csd: &CommitmentStateDiff, block_number: u64) -> Result<Felt252Wrapper, DeoxysStorageError> {
+    let mut handler_class = storage_handler::class_trie_mut();
+
+    let updates = csd
+        .class_hash_to_compiled_class_hash
+        .iter()
+        .par_bridge()
+        .map(|(class_hash, compiled_class_hash)| {
+            let compiled_class_hash = FieldElement::from_bytes_be(&compiled_class_hash.0.0).unwrap();
+
+            let hash = PoseidonHasher::hash_elements(CONTRACT_CLASS_HASH_VERSION, compiled_class_hash);
+
+            (class_hash, hash)
+        })
+        .collect::<Vec<_>>();
+
+    handler_class.init()?;
+    handler_class.update(updates)?;
+    handler_class.commit(block_number)?;
+
+    Ok(handler_class.root()?.into())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_contract_class_hash_version() {
+        assert_eq!(
+            CONTRACT_CLASS_HASH_VERSION,
+            FieldElement::from_byte_slice_be("CONTRACT_CLASS_LEAF_V0".as_bytes()).unwrap(),
+        );
+    }
+}