dexorder

lib_openzeppelin_contracts/contracts/mocks/ERC3156FlashBorrowerMock.sol

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+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import {IERC20} from "../token/ERC20/IERC20.sol";
+import {IERC3156FlashBorrower} from "../interfaces/IERC3156.sol";
+import {Address} from "../utils/Address.sol";
+
+/**
+ * @dev WARNING: this IERC3156FlashBorrower mock implementation is for testing purposes ONLY.
+ * Writing a secure flash lock borrower is not an easy task, and should be done with the utmost care.
+ * This is not an example of how it should be done, and no pattern present in this mock should be considered secure.
+ * Following best practices, always have your contract properly audited before using them to manipulate important funds on
+ * live networks.
+ */
+contract ERC3156FlashBorrowerMock is IERC3156FlashBorrower {
+    bytes32 internal constant _RETURN_VALUE = keccak256("ERC3156FlashBorrower.onFlashLoan");
+
+    bool immutable _enableApprove;
+    bool immutable _enableReturn;
+
+    event BalanceOf(address token, address account, uint256 value);
+    event TotalSupply(address token, uint256 value);
+
+    constructor(bool enableReturn, bool enableApprove) {
+        _enableApprove = enableApprove;
+        _enableReturn = enableReturn;
+    }
+
+    function onFlashLoan(
+        address /*initiator*/,
+        address token,
+        uint256 amount,
+        uint256 fee,
+        bytes calldata data
+    ) public returns (bytes32) {
+        require(msg.sender == token);
+
+        emit BalanceOf(token, address(this), IERC20(token).balanceOf(address(this)));
+        emit TotalSupply(token, IERC20(token).totalSupply());
+
+        if (data.length > 0) {
+            // WARNING: This code is for testing purposes only! Do not use.
+            Address.functionCall(token, data);
+        }
+
+        if (_enableApprove) {
+            IERC20(token).approve(token, amount + fee);
+        }
+
+        return _enableReturn ? _RETURN_VALUE : bytes32(0);
+    }
+}