Contract Address Details

// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.12;

import "@openzeppelin/contracts-upgradeable/proxy/Initializable.sol";

import "../external/compound/PriceOracle.sol";
import "../external/compound/CToken.sol";
import "../external/compound/CErc20.sol";

import "./BasePriceOracle.sol";

/**
 * @title MasterPriceOracle
 * @notice Use a combination of price oracles.
 * @dev Implements `PriceOracle`.
 * @author David Lucid <david@rari.capital> (https://github.com/davidlucid)
 */
contract MasterPriceOracle is Initializable, PriceOracle, BasePriceOracle {
    /**
     * @dev Maps underlying token addresses to `PriceOracle` contracts (can be `BasePriceOracle` contracts too).
     */
    mapping(address => PriceOracle) public oracles;

    /**
     * @dev Default/fallback `PriceOracle`.
     */
    PriceOracle public defaultOracle;

    /**
     * @dev The administrator of this `MasterPriceOracle`.
     */
    address public admin;

    /**
     * @dev Controls if `admin` can overwrite existing assignments of oracles to underlying tokens.
     */
    bool internal noAdminOverwrite;

    /**
     * @dev Returns a boolean indicating if `admin` can overwrite existing assignments of oracles to underlying tokens.
     */
    function canAdminOverwrite() external view returns (bool) {
        return !noAdminOverwrite;
    }

    /**
     * @dev Event emitted when `admin` is changed.
     */
    event NewAdmin(address oldAdmin, address newAdmin);

    /**
     * @dev Event emitted when the default oracle is changed.
     */
    event NewDefaultOracle(address oldOracle, address newOracle);

    /**
     * @dev Event emitted when an underlying token's oracle is changed.
     */
    event NewOracle(address underlying, address oldOracle, address newOracle);

    /**
     * @dev Constructor to initialize state variables.
     * @param underlyings The underlying ERC20 token addresses to link to `_oracles`.
     * @param _oracles The `PriceOracle` contracts to be assigned to `underlyings`.
     * @param _defaultOracle The default `PriceOracle` contract to use.
     * @param _admin The admin who can assign oracles to underlying tokens.
     * @param _canAdminOverwrite Controls if `admin` can overwrite existing assignments of oracles to underlying tokens.
     */
    function initialize(address[] memory underlyings, PriceOracle[] memory _oracles, PriceOracle _defaultOracle, address _admin, bool _canAdminOverwrite) external initializer {
        // Input validation
        require(underlyings.length == _oracles.length, "Lengths of both arrays must be equal.");

        // Initialize state variables
        for (uint256 i = 0; i < underlyings.length; i++) {
            address underlying = underlyings[i];
            PriceOracle newOracle = _oracles[i];
            oracles[underlying] = newOracle;
            emit NewOracle(underlying, address(0), address(newOracle));
        }

        defaultOracle = _defaultOracle;
        admin = _admin;
        noAdminOverwrite = !_canAdminOverwrite;
    }

    /**
     * @dev Sets `_oracles` for `underlyings`.
     */
    function add(address[] calldata underlyings, PriceOracle[] calldata _oracles) external onlyAdmin {
        // Input validation
        require(underlyings.length > 0 && underlyings.length == _oracles.length, "Lengths of both arrays must be equal and greater than 0.");

        // Assign oracles to underlying tokens
        for (uint256 i = 0; i < underlyings.length; i++) {
            address underlying = underlyings[i];
            address oldOracle = address(oracles[underlying]);
            if (noAdminOverwrite) require(oldOracle == address(0), "Admin cannot overwrite existing assignments of oracles to underlying tokens.");
            PriceOracle newOracle = _oracles[i];
            oracles[underlying] = newOracle;
            emit NewOracle(underlying, oldOracle, address(newOracle));
        }
    }

    /**
     * @dev Changes the admin and emits an event.
     */
    function setDefaultOracle(PriceOracle newOracle) external onlyAdmin {
        PriceOracle oldOracle = defaultOracle;
        defaultOracle = newOracle;
        emit NewDefaultOracle(address(oldOracle), address(newOracle));
    }

    /**
     * @dev Changes the admin and emits an event.
     */
    function changeAdmin(address newAdmin) external onlyAdmin {
        address oldAdmin = admin;
        admin = newAdmin;
        emit NewAdmin(oldAdmin, newAdmin);
    }

    /**
     * @dev Modifier that checks if `msg.sender == admin`.
     */
    modifier onlyAdmin {
        require(msg.sender == admin, "Sender is not the admin.");
        _;
    }

    /**
     * @notice Returns the price in ETH of the token underlying `cToken`.
     * @dev Implements the `PriceOracle` interface for Fuse pools (and Compound v2).
     * @return Price in ETH of the token underlying `cToken`, scaled by `10 ** (36 - underlyingDecimals)`.
     */
    function getUnderlyingPrice(CToken cToken) external override view returns (uint) {
        // Get underlying ERC20 token address
        address underlying = address(CErc20(address(cToken)).underlying());

        // Return 1e18 for WETH
        if (underlying == 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2) return 1e18;

        // Get underlying price from assigned oracle
        PriceOracle oracle = oracles[underlying];
        if (address(oracle) != address(0)) return oracle.getUnderlyingPrice(cToken);
        if (address(defaultOracle) != address(0)) return defaultOracle.getUnderlyingPrice(cToken);
        revert("Price oracle not found for this underlying token address.");
    }

    /**
     * @dev Attempts to return the price in ETH of `underlying` (implements `BasePriceOracle`).
     */
    function price(address underlying) external override view returns (uint) {
        // Return 1e18 for WETH
        if (underlying == 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2) return 1e18;

        // Get underlying price from assigned oracle
        PriceOracle oracle = oracles[underlying];
        if (address(oracle) != address(0)) return BasePriceOracle(address(oracle)).price(underlying);
        if (address(defaultOracle) != address(0)) return BasePriceOracle(address(defaultOracle)).price(underlying);
        revert("Price oracle not found for this underlying token address.");
    }
}