base transfer & refund

helix-bridge · Dec 20, 2023 · 0c458d3 · 0c458d3
1 parent 4af6387
commit 0c458d3
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Showing 4 changed files with 36 additions and 17 deletions.
diff --git a/helix-contract/contracts/mapping-token/v3/base/xTokenBacking.sol b/helix-contract/contracts/mapping-token/v3/base/xTokenBacking.sol
@@ -54,6 +54,8 @@ contract xTokenBacking is xTokenBridgeBase {
 
     // We use nonce to ensure that messages are not duplicated
     // especially in reorg scenarios, the destination chain use nonce to filter out duplicate deliveries. 
+    // nonce is user-defined, there is no requirement that it must not be repeated.
+    // But the transferId generated must not be repeated.
     function lockAndRemoteIssuing(
         uint256 _remoteChainId,
         address _originalToken,
@@ -124,8 +126,7 @@ contract xTokenBacking is xTokenBridgeBase {
         expendDailyLimit(_originalToken, _amount);
 
         bytes32 transferId = getTransferId(_nonce, block.chainid, _originalToken, _originSender, _recipient, _amount);
-        require(filledTransfers[transferId] == TRANSFER_UNFILLED, "message has been accepted");
-        filledTransfers[transferId] = TRANSFER_DELIVERED;
+        _handleTransfer(transferId);
 
         // native token do not use guard
         if (address(0) == _originalToken) {
@@ -182,12 +183,7 @@ contract xTokenBacking is xTokenBridgeBase {
     ) external payable {
         require(_originalSender == msg.sender || _recipient == msg.sender || dao == msg.sender, "invalid msgSender");
         bytes32 transferId = getTransferId(_nonce, _remoteChainId, _originalToken, _originalSender, _recipient, _amount);
-        // must not exist in successful issue list
-        uint256 filledTransfer = filledTransfers[transferId];
-        require(filledTransfer != TRANSFER_DELIVERED, "success message can't refund for failed");
-        if (filledTransfer != TRANSFER_REFUNDED) {
-            filledTransfers[transferId] = TRANSFER_REFUNDED;
-        }
+        _requestRefund(transferId);
         bytes memory unlockForFailed = encodeIssuingForUnlockFailureFromRemote(
             _originalToken,
             _originalSender,

diff --git a/helix-contract/contracts/mapping-token/v3/base/xTokenBridgeBase.sol b/helix-contract/contracts/mapping-token/v3/base/xTokenBridgeBase.sol
@@ -103,18 +103,46 @@ contract xTokenBridgeBase is Initializable, Pausable, AccessController, DailyLim
         messageId = IMessageId(service.sendService).latestSentMessageId();
     }
 
+    // request a cross-chain transfer
+    // 1. lock and remote issue
+    // 2. burn and remote unlock
+    // save the transferId if not exist, else revert
     function _requestTransfer(bytes32 _transferId) internal {
         require(requestInfos[_transferId].isRequested == false, "request exist");
         requestInfos[_transferId].isRequested = true;
     }
 
+    // receive a cross-chain refund request
+    // 1. request must be exist
+    // 2. can't repeat
     function _handleRefund(bytes32 _transferId) internal {
         RequestInfo memory requestInfo = requestInfos[_transferId];
         require(requestInfo.isRequested == true, "request not exist");
         require(requestInfo.hasRefundForFailed == false, "request has been refund");
         requestInfos[_transferId].hasRefundForFailed = true;
     }
 
+    // receive a cross-chain request
+    // must not filled
+    // fill the transfer with delivered transfer type
+    function _handleTransfer(bytes32 _transferId) internal {
+        require(filledTransfers[_transferId] == TRANSFER_UNFILLED, "!conflict");
+        filledTransfers[_transferId] = TRANSFER_DELIVERED;
+    }
+
+    // request a cross-chain refund
+    // 1. can retry
+    // 2. can't be filled by delivery
+    function _requestRefund(bytes32 _transferId) internal {
+        uint256 filledTransfer = filledTransfers[_transferId];
+        // already fill by refund, retry request
+        if (filledTransfer == TRANSFER_REFUNDED) {
+            return;
+        }
+        require(filledTransfer == TRANSFER_UNFILLED, "!conflict");
+        filledTransfers[_transferId] = TRANSFER_REFUNDED;
+    }
+
     function getTransferId(
         uint256 _nonce,
         uint256 _targetChainId,

diff --git a/helix-contract/contracts/mapping-token/v3/base/xTokenIssuing.sol b/helix-contract/contracts/mapping-token/v3/base/xTokenIssuing.sol
@@ -107,8 +107,7 @@ contract xTokenIssuing is xTokenBridgeBase {
         require(_amount > 0, "can not receive amount zero");
         expendDailyLimit(xToken, _amount);
 
-        require(filledTransfers[transferId] == TRANSFER_UNFILLED, "message has been accepted");
-        filledTransfers[transferId] = TRANSFER_DELIVERED;
+        _handleTransfer(transferId);
 
         address _guard = guard;
         if (_guard != address(0)) {
@@ -182,11 +181,7 @@ contract xTokenIssuing is xTokenBridgeBase {
     ) external payable {
         require(_originalSender == msg.sender || _recipient == msg.sender || dao == msg.sender, "invalid msgSender");
         bytes32 transferId = getTransferId(_nonce, _originalChainId, _originalToken, _originalSender, _recipient, _amount);
-        uint256 filledTransfer = filledTransfers[transferId];
-        require(filledTransfer != TRANSFER_DELIVERED, "success message can't refund for failed");
-        if (filledTransfer != TRANSFER_REFUNDED) {
-            filledTransfers[transferId] = TRANSFER_REFUNDED;
-        }
+        _requestRefund(transferId);
         bytes memory handleUnlockForFailed = encodeUnlockForIssuingFailureFromRemote(
             _originalToken,
             _originalSender,

diff --git a/helix-contract/test/6_test_xtoken_v3.js b/helix-contract/test/6_test_xtoken_v3.js
@@ -396,14 +396,14 @@ describe("xtoken tests", () => {
           nonce01,
           "1.1",
           true
-      )).to.be.revertedWith("success message can't refund for failed");
+      )).to.be.revertedWith("!conflict");
       await expect(requestRemoteIssuingForUnlockFailure(
           nativeTokenAddress,
           100,
           nonce02,
           "1.1",
           true
-      )).to.be.revertedWith("success message can't refund for failed");
+      )).to.be.revertedWith("!conflict");
 
       // lock exceed daily limit
       const nonce03 = await lockAndRemoteIssuing(