all files / plugins/assets/ NonFiatCollateral.sol

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// SPDX-License-Identifier: BlueOak-1.0.0
pragma solidity 0.8.17;
 
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "../../libraries/Fixed.sol";
import "./FiatCollateral.sol";
 
/**
 * @title NonFiatCollateral
 * @notice Collateral plugin for a nonfiat collateral that requires default checks, such as WBTC.
 * Expected: {tok} == {ref}, {ref} is pegged to {target} or defaulting, {target} != {UoA}
 */
contract NonFiatCollateral is FiatCollateral {
    using FixLib for uint192;
    using OracleLib for AggregatorV3Interface;
 
    AggregatorV3Interface public immutable targetUnitChainlinkFeed; // {UoA/target}
    uint48 public immutable targetUnitOracleTimeout; // {s}
 
    /// @param config.chainlinkFeed Feed units: {target/ref}
    /// @param targetUnitChainlinkFeed_ Feed units: {UoA/target}
    /// @param targetUnitOracleTimeout_ {s} oracle timeout to use for targetUnitChainlinkFeed
    constructor(
        CollateralConfig memory config,
        AggregatorV3Interface targetUnitChainlinkFeed_,
        uint48 targetUnitOracleTimeout_
    ) FiatCollateral(config) {
        Erequire(address(targetUnitChainlinkFeed_) != address(0), "missing targetUnit feed");
        Erequire(targetUnitOracleTimeout_ > 0, "targetUnitOracleTimeout zero");
        targetUnitChainlinkFeed = targetUnitChainlinkFeed_;
        targetUnitOracleTimeout = targetUnitOracleTimeout_;
    }
 
    /// 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}
    function tryPrice()
        external
        view
        override
        returns (
            uint192 low,
            uint192 high,
            uint192 pegPrice
        )
    {
        pegPrice = chainlinkFeed.price(oracleTimeout); // {target/ref}
 
        // Assumption: {ref/tok} = 1; inherit from `AppreciatingFiatCollateral` if need appreciation
        // {UoA/tok} = {UoA/target} * {target/ref} * {ref/tok} (1)
        uint192 p = targetUnitChainlinkFeed.price(targetUnitOracleTimeout).mul(pegPrice);
 
        // this oracleError is already the combined total oracle error
        uint192 err = p.mul(oracleError, CEIL);
 
        low = p - err;
        high = p + err;
        // assert(low <= high); obviously true just by inspection
    }
}