feat: approval support (#195)

Signed-off-by: Mariusz Jasuwienas <[email protected]>
hashgraph · Jan 23, 2025 · 15bf8a5 · 15bf8a5
1 parent 30e486a
commit 15bf8a5
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Showing 3 changed files with 68 additions and 60 deletions.
diff --git a/contracts/HtsSystemContract.sol b/contracts/HtsSystemContract.sol
@@ -45,7 +45,7 @@ contract HtsSystemContract is IHederaTokenService, IERC20Events, IERC721Events {
 
     function cryptoTransfer(TransferList memory transferList, TokenTransferList[] memory tokenTransfers)
         htsCall external returns (int64 responseCode) {
-        _cryptoHbarTransfer(transferList);
+        _cryptoHbarTransfers(transferList);
         for (uint256 tokenIndex = 0; tokenIndex < tokenTransfers.length; tokenIndex++) {
             require(tokenTransfers[tokenIndex].token != address(0), "cryptoTransfer: invalid token");
             uint256 validFungibleTransfersCount = 0;
@@ -927,7 +927,69 @@ contract HtsSystemContract is IHederaTokenService, IERC20Events, IERC721Events {
         emit ApprovalForAll(sender, operator, approved);
     }
 
-    function _cryptoHbarTransfer(TransferList memory transferList) internal virtual {
-        require(transferList.transfers.length == 0, "cryptoTransfer: hbar transfer is not supported");
+    function _cryptoHbarTransfers(TransferList memory transferList) internal {
+        int64 hbarBalance = 0;
+        for (uint256 i = 0; i < transferList.transfers.length; i++) {
+            // HBAR approval
+            if (transferList.transfers[i].isApproval) {
+                require(transferList.transfers[i].amount > 0, "cryptoTransfer: invalid amount");
+                hbarBalance += transferList.transfers[i].amount;
+                _approve(
+                    msg.sender,
+                    transferList.transfers[i].accountID,
+                    uint256(uint64(-transferList.transfers[i].amount))
+                );
+                continue;
+            }
+            require(transferList.transfers[i].amount != 0, "cryptoTransfer: invalid amount");
+
+            // HBAR transfer from
+            if (transferList.transfers[i].amount < 0) {
+                uint256 fromAmount = uint256(uint64(-transferList.transfers[i].amount));
+                require(
+                    fromAmount <= transferList.transfers[i].accountID.balance,
+                    "cryptoTransfer: insufficient balance"
+                );
+
+                // HBAR transferring as owner
+                if (transferList.transfers[i].accountID == msg.sender) {
+                    _updateHbarBalanceOnAccount(
+                        transferList.transfers[i].accountID,
+                        transferList.transfers[i].accountID.balance - fromAmount
+                    );
+                    continue;
+                }
+                // HBAR transferring from someone else's account
+                uint256 allowance = __allowance(transferList.transfers[i].accountID, msg.sender);
+                require(
+                    allowance >= transferList.transfers[i].accountID.balance,
+                    "cryptoTransfer: insufficient allowance"
+                );
+                _updateHbarBalanceOnAccount(
+                    transferList.transfers[i].accountID,
+                    transferList.transfers[i].accountID.balance - fromAmount
+                );
+                unchecked {
+                    _approve(
+                        transferList.transfers[i].accountID,
+                        msg.sender,
+                        allowance - transferList.transfers[i].accountID.balance
+                    );
+                }
+                continue;
+            }
+
+            // HBAR transfer to
+            uint256 toAmount = uint256(uint64(transferList.transfers[i].amount));
+            _updateHbarBalanceOnAccount(
+                transferList.transfers[i].accountID,
+                transferList.transfers[i].accountID.balance + toAmount
+            );
+        }
+        require(hbarBalance == 0, "cryptoTransfer: unmatched hbar transfers ");
+    }
+
+    function _updateHbarBalanceOnAccount(address account, uint256 newBalance) internal virtual {
+        revert("cryptoTransfer: hbar transfer on non-payable method is not supported");
     }
 }
diff --git a/contracts/HtsSystemContractJson.sol b/contracts/HtsSystemContractJson.sol
@@ -474,34 +474,7 @@ contract HtsSystemContractJson is HtsSystemContract {
         return address(bytes20(keccak256(abi.encode(address(this)))));
     }
 
-    function _cryptoHbarTransfer(TransferList memory transferList) internal override {
-        int64 hbarBalance = 0;
-        for (uint256 hbarIndex = 0; hbarIndex < transferList.transfers.length; hbarIndex++) {
-            require(transferList.transfers[hbarIndex].amount != 0, "cryptoTransfer: invalid amount");
-            require(!transferList.transfers[hbarIndex].isApproval, "cryptoTransfer: hbar approval is not supported");
-            hbarBalance += transferList.transfers[hbarIndex].amount;
-            if (transferList.transfers[hbarIndex].amount < 0) {
-                require(
-                    transferList.transfers[hbarIndex].accountID == msg.sender,
-                    "cryptoTransfer: hbar transfer allowed only from the msg sender account, approved transfers are not supported"
-                );
-                uint256 fromAmount = uint256(uint64(-transferList.transfers[hbarIndex].amount));
-                require(
-                    fromAmount <= transferList.transfers[hbarIndex].accountID.balance,
-                    "cryptoTransfer: insufficient balance"
-                );
-                vm.deal(
-                    transferList.transfers[hbarIndex].accountID,
-                    transferList.transfers[hbarIndex].accountID.balance - fromAmount
-                );
-                continue;
-            }
-            uint256 toAmount = uint256(uint64(transferList.transfers[hbarIndex].amount));
-            vm.deal(
-                transferList.transfers[hbarIndex].accountID,
-                transferList.transfers[hbarIndex].accountID.balance + toAmount
-            );
-        }
-        require(hbarBalance == 0, "cryptoTransfer: unmatched hbar transfers ");
+    function _updateHbarBalanceOnAccount(address account, uint256 newBalance) internal override {
+        vm.deal(account, newBalance);
     }
 }
diff --git a/test/HTS.t.sol b/test/HTS.t.sol
@@ -946,7 +946,7 @@ contract HTSTest is Test, TestSetup {
         transferList.transfers[1] = transfer2;
         vm.deal(owner, hbarToRecipient);
         vm.deal(sender, hbarToRecipient);
-        vm.expectRevert("cryptoTransfer: hbar transfer allowed only from the msg sender account, approved transfers are not supported");
+        vm.expectRevert("cryptoTransfer: insufficient allowance");
         vm.prank(owner);
         IHederaTokenService(HTS_ADDRESS).cryptoTransfer(
             transferList,
@@ -980,31 +980,4 @@ contract HTSTest is Test, TestSetup {
             new IHederaTokenService.TokenTransferList[](0)
         );
     }
-
-    function test_HTS_cryptoTransfer_test_reject_hbar_approval() external {
-        address owner = 0x4D1c823b5f15bE83FDf5adAF137c2a9e0E78fE15;
-        address recipient = makeAddr("recipient");
-        uint256 hbarToRecipient = 1 ether;
-        IHederaTokenService.AccountAmount memory transfer1 = IHederaTokenService.AccountAmount(
-            owner,
-            -int64(uint64(hbarToRecipient)),
-            false
-        );
-        IHederaTokenService.AccountAmount memory transfer2 = IHederaTokenService.AccountAmount(
-            recipient,
-            int64(uint64(hbarToRecipient)),
-            true
-        );
-        IHederaTokenService.TransferList memory transferList;
-        transferList.transfers = new IHederaTokenService.AccountAmount[](2);
-        transferList.transfers[0] = transfer1;
-        transferList.transfers[1] = transfer2;
-        vm.deal(owner, hbarToRecipient);
-        vm.expectRevert("cryptoTransfer: hbar approval is not supported");
-        vm.prank(owner);
-        IHederaTokenService(HTS_ADDRESS).cryptoTransfer(
-            transferList,
-            new IHederaTokenService.TokenTransferList[](0)
-        );
-    }
 }