Feat: WithdrawalRequestNFT

contracts/0.8.9/WithdrawalQueue.sol

@@ -7,7 +7,6 @@ pragma solidity 0.8.9;
 import {WithdrawalQueueBase} from "./WithdrawalQueueBase.sol";
 
 import {IERC20} from "@openzeppelin/contracts-v4.4/token/ERC20/IERC20.sol";
-import {IERC721} from "@openzeppelin/contracts-v4.4/token/ERC721/IERC721.sol";
 import {IERC20Permit} from "@openzeppelin/contracts-v4.4/token/ERC20/extensions/draft-IERC20Permit.sol";
 import {SafeCast} from "@openzeppelin/contracts-v4.4/utils/math/SafeCast.sol";
 import {SafeERC20} from "@openzeppelin/contracts-v4.4/token/ERC20/utils/SafeERC20.sol";
@@ -54,7 +53,7 @@ interface IWstETH is IERC20, IERC20Permit {
  * @title A contract for handling stETH withdrawal request queue within the Lido protocol
  * @author folkyatina
  */
-contract WithdrawalQueue is AccessControlEnumerable, WithdrawalQueueBase, Versioned {
+abstract contract WithdrawalQueue is AccessControlEnumerable, WithdrawalQueueBase, Versioned {
     using SafeCast for uint256;
     using SafeERC20 for IWstETH;
     using SafeERC20 for IStETH;
@@ -305,10 +304,35 @@ contract WithdrawalQueue is AccessControlEnumerable, WithdrawalQueueBase, Versio
     /// @param _claimWithdrawalInputs list of withdrawal request ids and hints to claim
     function claimWithdrawals(ClaimWithdrawalInput[] calldata _claimWithdrawalInputs) external {
         for (uint256 i = 0; i < _claimWithdrawalInputs.length; ++i) {
-            claimWithdrawal(_claimWithdrawalInputs[i].requestId, _claimWithdrawalInputs[i].hint);
+            _claimWithdrawalTo(_claimWithdrawalInputs[i].requestId, _claimWithdrawalInputs[i].hint, msg.sender);
+
+            _emitTransfer(msg.sender, address(0), _claimWithdrawalInputs[i].requestId);
         }
     }
 
+    ///  @notice Claim `_requestId` request and transfer locked ether to the owner
+    ///  @param _requestId request id to claim
+    ///  @param _hint hint for checkpoint index to avoid extensive search over the checkpointHistory.
+    ///   Can be found with `findClaimHint()` or `findClaimHintUnbounded()`
+    /// @param _recipient address where 
+    function claimWithdrawalTo(uint256 _requestId, uint256 _hint, address _recipient) external {
+        _claimWithdrawalTo(_requestId, _hint, _recipient);
+
+        _emitTransfer(msg.sender, address(0), _requestId);
+    }
+
+     /**
+     * @notice Claim `_requestId` request and transfer locked ether to the owner
+     * @param _requestId request id to claim
+     * @dev will use `findClaimHintUnbounded()` to find a hint, what can lead to OOG
+     * Prefer `claimWithdrawal(uint256 _requestId, uint256 _hint)` to save gas
+     */
+    function claimWithdrawal(uint256 _requestId) external {
+        _claimWithdrawalTo(_requestId, findClaimHintUnbounded(_requestId), msg.sender);
+
+        _emitTransfer(msg.sender, address(0), _requestId);
+    }
+
     /// @notice Finds the list of hints for the given `_requestIds` searching among the checkpoints with indices
     ///  in the range  `[_firstIndex, _lastIndex]`
     /// @param _requestIds ids of the requests sorted in the ascending order to get hints for
@@ -387,6 +411,8 @@ contract WithdrawalQueue is AccessControlEnumerable, WithdrawalQueueBase, Versio
         return BUNKER_MODE_SINCE_TIMESTAMP_POSITION.getStorageUint256();
     }
 
+    function _emitTransfer(address from, address to, uint256 _requestId) internal virtual; 
+
     /// @dev internal initialization helper. Doesn't check provided addresses intentionally
     function _initialize(address _admin, address _pauser, address _resumer, address _finalizer) internal {
         _initializeQueue();
@@ -409,7 +435,9 @@ contract WithdrawalQueue is AccessControlEnumerable, WithdrawalQueueBase, Versio
 
         uint256 amountOfShares = STETH.getSharesByPooledEth(_amountOfStETH);
 
-        return _enqueue(_amountOfStETH.toUint128(), amountOfShares.toUint128(), _owner);
+        requestId = _enqueue(_amountOfStETH.toUint128(), amountOfShares.toUint128(), _owner);
+
+        _emitTransfer(address(0), _owner, requestId);
     }
 
     function _requestWithdrawalWstETH(uint256 _amountOfWstETH, address _owner) internal returns (uint256 requestId) {
@@ -418,7 +446,9 @@ contract WithdrawalQueue is AccessControlEnumerable, WithdrawalQueueBase, Versio
 
         uint256 amountOfShares = STETH.getSharesByPooledEth(amountOfStETH);
 
-        return _enqueue(amountOfStETH.toUint128(), amountOfShares.toUint128(), _owner);
+        requestId = _enqueue(amountOfStETH.toUint128(), amountOfShares.toUint128(), _owner);
+
+        _emitTransfer(address(0), _owner, requestId);
     }
 
     function _checkWithdrawalRequestInput(uint256 _amountOfStETH, address _owner) internal view returns (address) {

contracts/0.8.9/WithdrawalQueueBase.sol

@@ -75,13 +75,13 @@ abstract contract WithdrawalQueueBase {
         uint256 indexed from, uint256 indexed to, uint256 amountOfETHLocked, uint256 sharesBurned, uint256 timestamp
     );
     event WithdrawalClaimed(
-        uint256 indexed requestId, address indexed receiver, address initiator, uint256 amountOfETH
+        uint256 indexed requestId, address owner, address indexed receiver, uint256 amountOfETH
     );
-    event WithdrawalRequestTransferred(uint256 indexed requestId, address newOwner, address oldOwner);
-
+
     error ZeroAmountOfETH();
     error ZeroShareRate();
     error ZeroTimestamp();
+    error ZeroRecipient();
     error InvalidOwner(address _owner, address _sender);
     error InvalidOwnerAddress(address _owner);
     error InvalidRequestId(uint256 _requestId);
@@ -93,7 +93,7 @@ abstract contract WithdrawalQueueBase {
     error CantSendValueRecipientMayHaveReverted();
     error SafeCastValueDoesNotFit(uint16 maximumBitSize);
 
-    /// @notice id of the last request. Equals to the length of the queue
+    /// @notice id of the last request.
     function getLastRequestId() public view returns (uint256) {
         return LAST_REQUEST_ID_POSITION.getStorageUint256();
     }
@@ -133,7 +133,7 @@ abstract contract WithdrawalQueueBase {
      * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
      */
     function getWithdrawalRequests(address _owner) external view returns (uint256[] memory requestsIds) {
-        return _getRequestByOwner()[_owner].values();
+        return _getRequestsByOwner()[_owner].values();
     }
 
     struct WithdrawalRequestStatus {
@@ -275,14 +275,17 @@ abstract contract WithdrawalQueueBase {
      * @param _hint hint for checkpoint index to avoid extensive search over the checkpointHistory.
      *  Can be found with `findClaimHint()` or `findClaimHintUnbounded()`
      */
-    function claimWithdrawal(uint256 _requestId, uint256 _hint) public {
+    function _claimWithdrawalTo(uint256 _requestId, uint256 _hint, address _recipient) internal {
         if (_hint == 0) revert InvalidHint(_hint);
+
         if (_requestId > getLastFinalizedRequestId()) revert RequestNotFinalized(_requestId);
         uint256 lastCheckpointIndex = getLastCheckpointIndex();
         if (_hint > lastCheckpointIndex) revert InvalidHint(_hint);
 
         WithdrawalRequest storage request = _getQueue()[_requestId];
         if (request.claimed) revert RequestAlreadyClaimed(_requestId);
+        if (msg.sender != request.owner) revert InvalidOwner(request.owner, msg.sender);
+        if (_recipient == address(0)) _recipient = request.owner;
 
         request.claimed = true;
 
@@ -303,44 +306,9 @@ abstract contract WithdrawalQueueBase {
 
         _setLockedEtherAmount(getLockedEtherAmount() - ethWithDiscount);
 
-        _sendValue(request.owner, ethWithDiscount);
-
-        emit WithdrawalClaimed(_requestId, request.owner, msg.sender, ethWithDiscount);
-    }
-
-    /**
-     * @notice Claim `_requestId` request and transfer locked ether to the owner
-     * @param _requestId request id to claim
-     * @dev will use `findClaimHintUnbounded()` to find a hint, what can lead to OOG
-     * Prefer `claimWithdrawal(uint256 _requestId, uint256 _hint)` to save gas
-     */
-    function claimWithdrawal(uint256 _requestId) external {
-        claimWithdrawal(_requestId, findClaimHintUnbounded(_requestId));
-    }
-
-    /**
-     * @notice Transfer the right to claim withdrawal request to `_newRecipient`
-     * @dev should be called by the old recipient
-     * @param _requestId id of the request subject to change
-     * @param _newOwner new owner address for withdrawal request
-     */
-    function transfer(uint256 _requestId, address _newOwner) external {
-        if (_newOwner == address(0)) revert InvalidOwnerAddress(_newOwner);
-        if (_newOwner == msg.sender) revert InvalidOwnerAddress(_newOwner);
-        if (_requestId == 0) revert InvalidRequestId(_requestId);
-        if (_requestId > getLastRequestId()) revert InvalidRequestId(_requestId);
-
-        WithdrawalRequest storage request = _getQueue()[_requestId];
-
-        if (request.owner != msg.sender) revert InvalidOwner(request.owner, msg.sender);
-        if (request.claimed) revert RequestAlreadyClaimed(_requestId);
-
-        request.owner = payable(_newOwner);
-
-        _getRequestByOwner()[_newOwner].add(_requestId);
-        _getRequestByOwner()[msg.sender].remove(_requestId);
+        _sendValue(payable(_recipient), ethWithDiscount);
 
-        emit WithdrawalRequestTransferred(_requestId, _newOwner, msg.sender);
+        emit WithdrawalClaimed(_requestId, msg.sender, _recipient, ethWithDiscount);
     }
 
     /**
@@ -457,7 +425,7 @@ abstract contract WithdrawalQueueBase {
         _setLastRequestId(requestId);
         _getQueue()[requestId] =
             WithdrawalRequest(cumulativeStETH, cumulativeShares, payable(_owner), uint64(block.number), false);
-        _getRequestByOwner()[_owner].add(requestId);
+        _getRequestsByOwner()[_owner].add(requestId);
 
         emit WithdrawalRequested(requestId, msg.sender, _owner, _amountOfStETH, _amountOfShares);
     }
@@ -535,14 +503,14 @@ abstract contract WithdrawalQueueBase {
         }
     }
 
-    function _getRequestByOwner()
+    function _getRequestsByOwner()
         internal
         pure
-        returns (mapping(address => EnumerableSet.UintSet) storage requestsByRecipient)
+        returns (mapping(address => EnumerableSet.UintSet) storage requestsByOwner)
     {
         bytes32 position = REQUEST_BY_OWNER_POSITION;
         assembly {
-            requestsByRecipient.slot := position
+            requestsByOwner.slot := position
         }
     }