all files / plugins/assets/rocket-eth/ RethCollateral.sol

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// SPDX-License-Identifier: BlueOak-1.0.0
pragma solidity 0.8.17;
 
import "@openzeppelin/contracts/utils/math/Math.sol";
import "../../../libraries/Fixed.sol";
import "../AppreciatingFiatCollateral.sol";
import "../OracleLib.sol";
import "./IReth.sol";
 
/**
 * @title RethCollateral
 * @notice Collateral plugin for Rocket-Pool ETH,
 * tok = rETH
 * ref = ETH
 * tar = ETH
 * UoA = USD
 */
contract RethCollateral is AppreciatingFiatCollateral {
    using OracleLib for AggregatorV3Interface;
    using FixLib for uint192;
 
    AggregatorV3Interface public immutable refPerTokChainlinkFeed;
    uint48 public immutable refPerTokChainlinkTimeout;
 
    /// @param config.chainlinkFeed Feed units: {UoA/ref}
    constructor(
        CollateralConfig memory config,
        uint192 revenueHiding,
        AggregatorV3Interface _refPerTokChainlinkFeed,
        uint48 _refPerTokChainlinkTimeout
    ) AppreciatingFiatCollateral(config, revenueHiding) {
        Erequire(address(_refPerTokChainlinkFeed) != address(0), "missing refPerTok feed");
        Erequire(_refPerTokChainlinkTimeout != 0, "refPerTokChainlinkTimeout zero");
        refPerTokChainlinkFeed = _refPerTokChainlinkFeed;
        refPerTokChainlinkTimeout = _refPerTokChainlinkTimeout;
    }
 
    /// Can revert, used by other contract functions in order to catch errors
    /// @return low {UoA/tok} The low price estimate
    /// @return high {UoA/tok} The high price estimate
    /// @return pegPrice {target/ref} The actual price observed in the peg
    function tryPrice()
        external
        view
        override
        returns (
            uint192 low,
            uint192 high,
            uint192 pegPrice
        )
    {
        // {UoA/tok} = {UoA/ref} * {ref/tok}
        uint192 p = chainlinkFeed.price(oracleTimeout).mul(
            refPerTokChainlinkFeed.price(refPerTokChainlinkTimeout)
        );
        uint192 err = p.mul(oracleError, CEIL);
 
        high = p + err;
        low = p - err;
        // assert(low <= high); obviously true just by inspection
 
        pegPrice = targetPerRef(); // {target/ref} ETH/ETH is always 1
    }
 
    /// @return {ref/tok} Quantity of whole reference units per whole collateral tokens
    function _underlyingRefPerTok() internal view override returns (uint192) {
        return _safeWrap(IReth(address(erc20)).getExchangeRate());
    }
}