From a6ac896a2e8f4c7b81241b8c7ffb1215221f9154 Mon Sep 17 00:00:00 2001
From: HAOYUatHZ <37070449+HAOYUatHZ@users.noreply.github.com>
Date: Tue, 24 Oct 2023 16:06:16 +0800
Subject: [PATCH] rollup: add `rollup/withdrawtrie` package (#543)

---
 rollup/withdrawtrie/withdraw_trie.go | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 rollup/withdrawtrie/withdraw_trie.go

diff --git a/rollup/withdrawtrie/withdraw_trie.go b/rollup/withdrawtrie/withdraw_trie.go
new file mode 100644
index 0000000000..22e51139a4
--- /dev/null
+++ b/rollup/withdrawtrie/withdraw_trie.go
@@ -0,0 +1,18 @@
+package withdrawtrie
+
+import (
+    "github.com/scroll-tech/go-ethereum/common"
+    "github.com/scroll-tech/go-ethereum/rollup/rcfg"
+)
+
+// StateDB represents the StateDB interface
+// required to get withdraw trie root
+type StateDB interface {
+    GetState(common.Address, common.Hash) common.Hash
+}
+
+// ReadWTRSlot reads WithdrawTrieRoot slot in L2MessageQueue predeploy, i.e., `messageRoot`
+// in contracts/src/libraries/common/AppendOnlyMerkleTree.sol
+func ReadWTRSlot(addr common.Address, state StateDB) common.Hash {
+    return state.GetState(addr, rcfg.WithdrawTrieRootSlot)
+}