feat/implement ERC721 deposit/withdraw

contracts/mainnet/connectors/basic-ERC721/events.sol

@@ -0,0 +1,14 @@
+pragma solidity ^0.7.0;
+
+contract Events {
+    event LogDepositERC721(
+        address indexed erc721,
+        address from,
+        uint256 tokenId
+    );
+    event LogWithdrawERC721(
+        address indexed erc721,
+        uint256 tokenId,
+        address indexed to
+    );
+}

contracts/mainnet/connectors/basic-ERC721/main.sol

@@ -0,0 +1,58 @@
+pragma solidity ^0.7.0;
+
+/**
+ * @title Basic.
+ * @dev Deposit & Withdraw from DSA.
+ */
+import {IERC721} from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
+
+import {DSMath} from "../../common/math.sol";
+import {Basic} from "../../common/basic.sol";
+import {Events} from "./events.sol";
+
+abstract contract BasicResolver is Events, DSMath, Basic {
+    /**
+     * @dev Deposit Assets To Smart Account.
+     * @notice Deposit a ERC721 token to DSA
+     * @param token The address of the token to deposit.
+     * @param tokenId The id of token to deposit.
+     */
+    function depositERC721(address token, uint256 tokenId)
+        public
+        payable
+        returns (string memory _eventName, bytes memory _eventParam)
+    {
+        IERC721 tokenContract = IERC721(token);
+        tokenContract.safeTransferFrom(msg.sender, address(this), tokenId);
+
+        _eventName = "LogDepositERC721(address,address,uint256)";
+        _eventParam = abi.encode(token, msg.sender, tokenId);
+    }
+
+    /**
+     * @dev Withdraw Assets To Smart Account.
+     * @notice Withdraw a ERC721 token from DSA
+     * @param token The address of the token to deposit.
+     * @param tokenId The id of token to deposit.
+     * @param to The address to receive the token upon withdrawal
+     */
+    function withdrawERC721(
+        address token,
+        uint256 tokenId,
+        address payable to
+    )
+        public
+        payable
+        returns (string memory _eventName, bytes memory _eventParam)
+    {
+        IERC721 tokenContract = IERC721(token);
+        tokenContract.safeTransferFrom(address(this), to, tokenId);
+
+        _eventName = "LogWithdrawERC721(address,uint256,address)";
+        _eventParam = abi.encode(token, tokenId, to);
+    }
+}
+
+contract ConnectV2Basic is BasicResolver {
+    string public constant name = "BASIC-ERC721-A";
+}