93 lines
3.6 KiB
Solidity
93 lines
3.6 KiB
Solidity
// 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);
|
|
}
|