OnTokenTransferAdapter (#7)

* Implement `OnTokenTransferAdapter` that rewrites 667 hooks as ERC-1363

* documentation

* Update OnTokenTransferAdapter.sol

contracts/token/OnTokenTransferAdapter.sol

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import {IERC1363Receiver} from "@openzeppelin/contracts/interfaces/IERC1363Receiver.sol";
+
+/**
+ * @dev This contract exposes the 667 `onTokenTransfer` hook on top of {IERC1363Receiver-onTransferReceived}.
+ *
+ * Inheriting from this adapter makes your `ERC1363Receiver` contract automatically compatible with tokens, such as
+ * Chainlink's Link, that implement the 667 interface for transferAndCall.
+ */
+abstract contract OnTokenTransferAdapter is IERC1363Receiver {
+    function onTokenTransfer(address from, uint256 amount, bytes calldata data) public virtual returns (bool) {
+        // Rewrite call as IERC1363.onTransferReceived
+        // This uses delegate call to keep the correct sender (token contracts)
+        //
+        // Note that since 667 doesn't implement `transferFromAndCall`, this hook was called by a simple
+        // `transferAndCall` and thus the operator is necessarily the `from` address.
+        (bool success, bytes memory returndata) = address(this).delegatecall(
+            abi.encodeCall(IERC1363Receiver.onTransferReceived, (from, from, amount, data))
+        );
+        // check success and return as boolean
+        return
+            success &&
+            returndata.length >= 0x20 &&
+            abi.decode(returndata, (bytes4)) == IERC1363Receiver.onTransferReceived.selector;
+    }
+}