feat(protocol): allow one-tx claim and delegation for bridged ERC20 tokens

packages/protocol/contracts/team/airdrop/ERC20Airdrop.sol

@@ -15,6 +15,7 @@
 pragma solidity 0.8.24;
 
 import "lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
+import "lib/openzeppelin-contracts-upgradeable/contracts/governance/utils/IVotesUpgradeable.sol";
 import "./MerkleClaimable.sol";
 
 /// @title ERC20Airdrop
@@ -41,8 +42,20 @@ contract ERC20Airdrop is MerkleClaimable {
         vault = _vault;
     }
 
-    function _claimWithData(bytes calldata data) internal override {
+    function _claimWithData(bytes calldata data, bytes memory extraData) internal override {
         (address user, uint256 amount) = abi.decode(data, (address, uint256));
+
+        // Transfer the token first
         IERC20(token).transferFrom(vault, user, amount);
+
+        if (extraData.length > 0) {
+            // Delegate the voting power to delegatee.
+            // Note that the signature (v,r,s) may not correspond to the user address,
+            // but since the data is provided by Taiko backend, it's not an issue even if
+            // client can change the data to call delegateBySig for another user.
+            (address delegatee, uint256 nonce, uint256 expiry, uint8 v, bytes32 r, bytes32 s) =
+                abi.decode(extraData, (address, uint256, uint256, uint8, bytes32, bytes32));
+            IVotesUpgradeable(token).delegateBySig(delegatee, nonce, expiry, v, r, s);
+        }
     }
 }

packages/protocol/contracts/team/airdrop/ERC20Airdrop2.sol

@@ -38,6 +38,7 @@ contract ERC20Airdrop2 is MerkleClaimable {
     event Withdrawn(address user, uint256 amount);
 
     error WITHDRAWALS_NOT_ONGOING();
+    error INVALID_DATA();
 
     modifier ongoingWithdrawals() {
         if (claimEnd > block.timestamp || claimEnd + withdrawalWindow < block.timestamp) {
@@ -103,7 +104,8 @@ contract ERC20Airdrop2 is MerkleClaimable {
         withdrawableAmount = timeBasedAllowance - withdrawnAmount[user];
     }
 
-    function _claimWithData(bytes calldata data) internal override {
+    function _claimWithData(bytes calldata data, bytes memory extraData) internal override {
+        if (extraData.length != 0) revert INVALID_DATA();
         (address user, uint256 amount) = abi.decode(data, (address, uint256));
         claimedAmount[user] += amount;
     }

packages/protocol/contracts/team/airdrop/ERC721Airdrop.sol

@@ -23,6 +23,8 @@ contract ERC721Airdrop is MerkleClaimable {
     address public vault;
     uint256[48] private __gap;
 
+    error INVALID_DATA();
+
     function init(
         uint64 _claimStarts,
         uint64 _claimEnds,
@@ -40,7 +42,8 @@ contract ERC721Airdrop is MerkleClaimable {
         vault = _vault;
     }
 
-    function _claimWithData(bytes calldata data) internal override {
+    function _claimWithData(bytes calldata data, bytes memory extraData) internal override {
+        if (extraData.length != 0) revert INVALID_DATA();
         (address user, uint256[] memory tokenIds) = abi.decode(data, (address, uint256[]));
 
         for (uint256 i; i < tokenIds.length; ++i) {

packages/protocol/contracts/team/airdrop/MerkleClaimable.sol

@@ -44,11 +44,33 @@ abstract contract MerkleClaimable is EssentialContract {
 
     function claim(
         bytes calldata data,
+        bytes calldata extraData,
         bytes32[] calldata proof
     )
         external
         nonReentrant
         ongoingClaim
+    {
+        _claim(data, extraData, proof);
+    }
+
+    function claim(
+        bytes calldata data,
+        bytes32[] calldata proof
+    )
+        external
+        nonReentrant
+        ongoingClaim
+    {
+        _claim(data, bytes(""), proof);
+    }
+
+    function _claim(
+        bytes calldata data,
+        bytes memory extraData,
+        bytes32[] calldata proof
+    )
+        private
     {
         bytes32 hash = keccak256(abi.encode("CLAIM_TAIKO_AIRDROP", data));
 
@@ -59,7 +81,7 @@ abstract contract MerkleClaimable is EssentialContract {
         }
 
         isClaimed[hash] = true;
-        _claimWithData(data);
+        _claimWithData(data, extraData);
         emit Claimed(hash);
     }
 
@@ -85,5 +107,5 @@ abstract contract MerkleClaimable is EssentialContract {
     }
 
     /// @dev Must revert in case of errors.
-    function _claimWithData(bytes calldata data) internal virtual;
+    function _claimWithData(bytes calldata data, bytes memory extraData) internal virtual;
 }