feat: add balancer v2 executor

foundry/lib/balancer-labs/v2-interfaces/contracts/standalone-utils/IwstETH.sol

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+pragma solidity >=0.7.0 <0.9.0;
+
+import "../solidity-utils/openzeppelin/IERC20.sol";
+
+import "./IstETH.sol";
+
+// solhint-disable-next-line max-line-length
+// Based on https://github.com/lidofinance/lido-dao/blob/2b46615a11dee77d4d22066f942f6c6afab9b87a/contracts/0.6.12/WstETH.sol
+
+/**
+ * @title StETH token wrapper with static balances.
+ * @dev It's an ERC20 token that represents the account's share of the total
+ * supply of stETH tokens. WstETH token's balance only changes on transfers,
+ * unlike StETH that is also changed when oracles report staking rewards and
+ * penalties. It's a "power user" token for DeFi protocols which don't
+ * support rebasable tokens.
+ *
+ * The contract is also a trustless wrapper that accepts stETH tokens and mints
+ * wstETH in return. Then the user unwraps, the contract burns user's wstETH
+ * and sends user locked stETH in return.
+ *
+ * The contract provides the staking shortcut: user can send ETH with regular
+ * transfer and get wstETH in return. The contract will send ETH to Lido submit
+ * method, staking it and wrapping the received stETH.
+ *
+ */
+interface IwstETH is IERC20 {
+    function stETH() external returns (IstETH);
+
+    /**
+     * @notice Exchanges stETH to wstETH
+     * @param _stETHAmount amount of stETH to wrap in exchange for wstETH
+     * @dev Requirements:
+     *  - `_stETHAmount` must be non-zero
+     *  - msg.sender must approve at least `_stETHAmount` stETH to this
+     *    contract.
+     *  - msg.sender must have at least `_stETHAmount` of stETH.
+     * User should first approve _stETHAmount to the WstETH contract
+     * @return Amount of wstETH user receives after wrap
+     */
+    function wrap(uint256 _stETHAmount) external returns (uint256);
+
+    /**
+     * @notice Exchanges wstETH to stETH
+     * @param _wstETHAmount amount of wstETH to uwrap in exchange for stETH
+     * @dev Requirements:
+     *  - `_wstETHAmount` must be non-zero
+     *  - msg.sender must have at least `_wstETHAmount` wstETH.
+     * @return Amount of stETH user receives after unwrap
+     */
+    function unwrap(uint256 _wstETHAmount) external returns (uint256);
+
+    /**
+     * @notice Get amount of wstETH for a given amount of stETH
+     * @param _stETHAmount amount of stETH
+     * @return Amount of wstETH for a given stETH amount
+     */
+    function getWstETHByStETH(uint256 _stETHAmount) external view returns (uint256);
+
+    /**
+     * @notice Get amount of stETH for a given amount of wstETH
+     * @param _wstETHAmount amount of wstETH
+     * @return Amount of stETH for a given wstETH amount
+     */
+    function getStETHByWstETH(uint256 _wstETHAmount) external view returns (uint256);
+
+    /**
+     * @notice Get amount of wstETH for a one stETH
+     * @return Amount of stETH for 1 wstETH
+     */
+    function stEthPerToken() external view returns (uint256);
+
+    /**
+     * @notice Get amount of stETH for a one wstETH
+     * @return Amount of wstETH for a 1 stETH
+     */
+    function tokensPerStEth() external view returns (uint256);
+}