Contract Source Code:

pragma solidity ^0.5.16;

import "./CTokenInterfaces.sol";

/**
 * @title Compound's CErc20Delegator Contract
 * @notice CTokens which wrap an EIP-20 underlying and delegate to an implementation
 * @author Compound
 */
contract CErc20Delegator is CDelegatorInterface, CTokenAdminStorage {
    /**
     * @notice Construct a new money market
     * @param underlying_ The address of the underlying asset
     * @param comptroller_ The address of the Comptroller
     * @param interestRateModel_ The address of the interest rate model
     * @param initialExchangeRateMantissa_ The initial exchange rate, scaled by 1e18
     * @param name_ ERC-20 name of this token
     * @param symbol_ ERC-20 symbol of this token
     * @param decimals_ ERC-20 decimal precision of this token
     * @param admin_ Address of the administrator of this token
     * @param implementation_ The address of the implementation the contract delegates to
     * @param becomeImplementationData The encoded args for becomeImplementation
     */
    constructor(address underlying_,
                ComptrollerInterface comptroller_,
                InterestRateModel interestRateModel_,
                uint initialExchangeRateMantissa_,
                string memory name_,
                string memory symbol_,
                uint8 decimals_,
                address payable admin_,
                address implementation_,
                bytes memory becomeImplementationData,
                uint256 reserveFactorMantissa_,
                uint256 adminFeeMantissa_) public {
        // Creator of the contract is admin during initialization
        admin = msg.sender;

        // First delegate gets to initialize the delegator (i.e. storage contract)
        delegateTo(implementation_, abi.encodeWithSignature("initialize(address,address,address,uint256,string,string,uint8,uint256,uint256)",
                                                            underlying_,
                                                            comptroller_,
                                                            interestRateModel_,
                                                            initialExchangeRateMantissa_,
                                                            name_,
                                                            symbol_,
                                                            decimals_,
                                                            reserveFactorMantissa_,
                                                            adminFeeMantissa_));

        // New implementations always get set via the settor (post-initialize)
        _setImplementation(implementation_, false, becomeImplementationData);

        // Set the proper admin now that initialization is done
        admin = admin_;
    }

    /**
     * @notice Called by the admin to update the implementation of the delegator
     * @param implementation_ The address of the new implementation for delegation
     * @param allowResign Flag to indicate whether to call _resignImplementation on the old implementation
     * @param becomeImplementationData The encoded bytes data to be passed to _becomeImplementation
     */
    function _setImplementation(address implementation_, bool allowResign, bytes memory becomeImplementationData) public {
        require(hasAdminRights(), "CErc20Delegator::_setImplementation: Caller must be admin");

        if (allowResign) {
            delegateToImplementation(abi.encodeWithSignature("_resignImplementation()"));
        }

        address oldImplementation = implementation;
        implementation = implementation_;

        delegateToImplementation(abi.encodeWithSignature("_becomeImplementation(bytes)", becomeImplementationData));

        emit NewImplementation(oldImplementation, implementation);
    }

    /**
     * @notice Internal method to delegate execution to another contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     * @param callee The contract to delegatecall
     * @param data The raw data to delegatecall
     * @return The returned bytes from the delegatecall
     */
    function delegateTo(address callee, bytes memory data) internal returns (bytes memory) {
        (bool success, bytes memory returnData) = callee.delegatecall(data);
        assembly {
            if eq(success, 0) {
                revert(add(returnData, 0x20), returndatasize)
            }
        }
        return returnData;
    }

    /**
     * @notice Delegates execution to the implementation contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     * @param data The raw data to delegatecall
     * @return The returned bytes from the delegatecall
     */
    function delegateToImplementation(bytes memory data) public returns (bytes memory) {
        return delegateTo(implementation, data);
    }

    /**
     * @notice Delegates execution to an implementation contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     */
    function () external payable {
        require(msg.value == 0,"CErc20Delegator:fallback: cannot send value to fallback");

        // delegate all other functions to current implementation
        (bool success, ) = implementation.delegatecall(msg.data);

        assembly {
            let free_mem_ptr := mload(0x40)
            returndatacopy(free_mem_ptr, 0, returndatasize)

            switch success
            case 0 { revert(free_mem_ptr, returndatasize) }
            default { return(free_mem_ptr, returndatasize) }
        }
    }
}

pragma solidity ^0.5.16;

contract ComptrollerInterface {
    /// @notice Indicator that this is a Comptroller contract (for inspection)
    bool public constant isComptroller = true;

    /*** Assets You Are In ***/

    function enterMarkets(address[] calldata cTokens) external returns (uint[] memory);
    function exitMarket(address cToken) external returns (uint);

    /*** Policy Hooks ***/

    function mintAllowed(address cToken, address minter, uint mintAmount) external returns (uint);
    function mintWithinLimits(address cToken, uint exchangeRateMantissa, uint accountTokens, uint mintAmount) external returns (uint);
    function mintVerify(address cToken, address minter, uint mintAmount, uint mintTokens) external;

    function redeemAllowed(address cToken, address redeemer, uint redeemTokens) external returns (uint);
    function redeemVerify(address cToken, address redeemer, uint redeemAmount, uint redeemTokens) external;

    function borrowAllowed(address cToken, address borrower, uint borrowAmount) external returns (uint);
    function borrowWithinLimits(address cToken, uint accountBorrowsNew) external returns (uint);
    function borrowVerify(address cToken, address borrower, uint borrowAmount) external;

    function repayBorrowAllowed(
        address cToken,
        address payer,
        address borrower,
        uint repayAmount) external returns (uint);
    function repayBorrowVerify(
        address cToken,
        address payer,
        address borrower,
        uint repayAmount,
        uint borrowerIndex) external;

    function liquidateBorrowAllowed(
        address cTokenBorrowed,
        address cTokenCollateral,
        address liquidator,
        address borrower,
        uint repayAmount) external returns (uint);
    function liquidateBorrowVerify(
        address cTokenBorrowed,
        address cTokenCollateral,
        address liquidator,
        address borrower,
        uint repayAmount,
        uint seizeTokens) external;

    function seizeAllowed(
        address cTokenCollateral,
        address cTokenBorrowed,
        address liquidator,
        address borrower,
        uint seizeTokens) external returns (uint);
    function seizeVerify(
        address cTokenCollateral,
        address cTokenBorrowed,
        address liquidator,
        address borrower,
        uint seizeTokens) external;

    function transferAllowed(address cToken, address src, address dst, uint transferTokens) external returns (uint);
    function transferVerify(address cToken, address src, address dst, uint transferTokens) external;

    /*** Liquidity/Liquidation Calculations ***/

    function liquidateCalculateSeizeTokens(
        address cTokenBorrowed,
        address cTokenCollateral,
        uint repayAmount) external view returns (uint, uint);
}

pragma solidity ^0.5.16;

import "./IFuseFeeDistributor.sol";
import "./ComptrollerInterface.sol";
import "./InterestRateModel.sol";

contract CTokenAdminStorage {
    /**
     * @notice Administrator for Fuse
     */
    IFuseFeeDistributor internal constant fuseAdmin = IFuseFeeDistributor(0xa731585ab05fC9f83555cf9Bff8F58ee94e18F85);

    /**
     * @notice Administrator for this contract
     */
    address payable public admin;

    /**
     * @notice Whether or not the Fuse admin has admin rights
     */
    bool public fuseAdminHasRights = true;

    /**
     * @notice Whether or not the admin has admin rights
     */
    bool public adminHasRights = true;

    /**
     * @notice Returns a boolean indicating if the sender has admin rights
     */
    function hasAdminRights() internal view returns (bool) {
        return (msg.sender == admin && adminHasRights) || (msg.sender == address(fuseAdmin) && fuseAdminHasRights);
    }
}

contract CTokenStorage is CTokenAdminStorage {
    /**
     * @dev Guard variable for re-entrancy checks
     */
    bool internal _notEntered;

    /**
     * @notice EIP-20 token name for this token
     */
    string public name;

    /**
     * @notice EIP-20 token symbol for this token
     */
    string public symbol;

    /**
     * @notice EIP-20 token decimals for this token
     */
    uint8 public decimals;

    /**
     * @notice Maximum borrow rate that can ever be applied (.0005% / block)
     */
    uint internal constant borrowRateMaxMantissa = 0.0005e16;

    /**
     * @notice Maximum fraction of interest that can be set aside for reserves + fees
     */
    uint internal constant reserveFactorPlusFeesMaxMantissa = 1e18;

    /**
     * @notice Pending administrator for this contract
     */
    address payable public pendingAdmin;

    /**
     * @notice Contract which oversees inter-cToken operations
     */
    ComptrollerInterface public comptroller;

    /**
     * @notice Model which tells what the current interest rate should be
     */
    InterestRateModel public interestRateModel;

    /**
     * @notice Initial exchange rate used when minting the first CTokens (used when totalSupply = 0)
     */
    uint internal initialExchangeRateMantissa;

    /**
     * @notice Fraction of interest currently set aside for admin fees
     */
    uint public adminFeeMantissa;

    /**
     * @notice Fraction of interest currently set aside for Fuse fees
     */
    uint public fuseFeeMantissa;

    /**
     * @notice Fraction of interest currently set aside for reserves
     */
    uint public reserveFactorMantissa;

    /**
     * @notice Block number that interest was last accrued at
     */
    uint public accrualBlockNumber;

    /**
     * @notice Accumulator of the total earned interest rate since the opening of the market
     */
    uint public borrowIndex;

    /**
     * @notice Total amount of outstanding borrows of the underlying in this market
     */
    uint public totalBorrows;

    /**
     * @notice Total amount of reserves of the underlying held in this market
     */
    uint public totalReserves;

    /**
     * @notice Total amount of admin fees of the underlying held in this market
     */
    uint public totalAdminFees;

    /**
     * @notice Total amount of Fuse fees of the underlying held in this market
     */
    uint public totalFuseFees;

    /**
     * @notice Total number of tokens in circulation
     */
    uint public totalSupply;

    /**
     * @notice Official record of token balances for each account
     */
    mapping (address => uint) internal accountTokens;

    /**
     * @notice Approved token transfer amounts on behalf of others
     */
    mapping (address => mapping (address => uint)) internal transferAllowances;

    /**
     * @notice Container for borrow balance information
     * @member principal Total balance (with accrued interest), after applying the most recent balance-changing action
     * @member interestIndex Global borrowIndex as of the most recent balance-changing action
     */
    struct BorrowSnapshot {
        uint principal;
        uint interestIndex;
    }

    /**
     * @notice Mapping of account addresses to outstanding borrow balances
     */
    mapping(address => BorrowSnapshot) internal accountBorrows;
}

contract CTokenInterface is CTokenStorage {
    /**
     * @notice Indicator that this is a CToken contract (for inspection)
     */
    bool public constant isCToken = true;

    /**
     * @notice Indicator that this is or is not a CEther contract (for inspection)
     */
    bool public constant isCEther = false;


    /*** Market Events ***/

    /**
     * @notice Event emitted when interest is accrued
     */
    event AccrueInterest(uint cashPrior, uint interestAccumulated, uint borrowIndex, uint totalBorrows);

    /**
     * @notice Event emitted when tokens are minted
     */
    event Mint(address minter, uint mintAmount, uint mintTokens);

    /**
     * @notice Event emitted when tokens are redeemed
     */
    event Redeem(address redeemer, uint redeemAmount, uint redeemTokens);

    /**
     * @notice Event emitted when underlying is borrowed
     */
    event Borrow(address borrower, uint borrowAmount, uint accountBorrows, uint totalBorrows);

    /**
     * @notice Event emitted when a borrow is repaid
     */
    event RepayBorrow(address payer, address borrower, uint repayAmount, uint accountBorrows, uint totalBorrows);

    /**
     * @notice Event emitted when a borrow is liquidated
     */
    event LiquidateBorrow(address liquidator, address borrower, uint repayAmount, address cTokenCollateral, uint seizeTokens);


    /*** Admin Events ***/

    /**
     * @notice Event emitted when the Fuse admin renounces their rights
     */
    event FuseAdminRightsRenounced();

    /**
     * @notice Event emitted when the admin renounces their rights
     */
    event AdminRightsRenounced();

    /**
     * @notice Event emitted when pendingAdmin is changed
     */
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);

    /**
     * @notice Event emitted when pendingAdmin is accepted, which means admin is updated
     */
    event NewAdmin(address oldAdmin, address newAdmin);

    /**
     * @notice Event emitted when comptroller is changed
     */
    event NewComptroller(ComptrollerInterface oldComptroller, ComptrollerInterface newComptroller);

    /**
     * @notice Event emitted when interestRateModel is changed
     */
    event NewMarketInterestRateModel(InterestRateModel oldInterestRateModel, InterestRateModel newInterestRateModel);

    /**
     * @notice Event emitted when the reserve factor is changed
     */
    event NewReserveFactor(uint oldReserveFactorMantissa, uint newReserveFactorMantissa);

    /**
     * @notice Event emitted when the reserves are added
     */
    event ReservesAdded(address benefactor, uint addAmount, uint newTotalReserves);

    /**
     * @notice Event emitted when the reserves are reduced
     */
    event ReservesReduced(address admin, uint reduceAmount, uint newTotalReserves);

    /**
     * @notice Event emitted when the admin fee is changed
     */
    event NewAdminFee(uint oldAdminFeeMantissa, uint newAdminFeeMantissa);

    /**
     * @notice Event emitted when the Fuse fee is changed
     */
    event NewFuseFee(uint oldFuseFeeMantissa, uint newFuseFeeMantissa);

    /**
     * @notice EIP20 Transfer event
     */
    event Transfer(address indexed from, address indexed to, uint amount);

    /**
     * @notice EIP20 Approval event
     */
    event Approval(address indexed owner, address indexed spender, uint amount);

    /**
     * @notice Failure event
     */
    event Failure(uint error, uint info, uint detail);


    /*** User Interface ***/

    function transfer(address dst, uint amount) external returns (bool);
    function transferFrom(address src, address dst, uint amount) external returns (bool);
    function approve(address spender, uint amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function balanceOfUnderlying(address owner) external returns (uint);
    function getAccountSnapshot(address account) external view returns (uint, uint, uint, uint);
    function borrowRatePerBlock() external view returns (uint);
    function supplyRatePerBlock() external view returns (uint);
    function totalBorrowsCurrent() external returns (uint);
    function borrowBalanceCurrent(address account) external returns (uint);
    function borrowBalanceStored(address account) public view returns (uint);
    function exchangeRateCurrent() public returns (uint);
    function exchangeRateStored() public view returns (uint);
    function getCash() external view returns (uint);
    function accrueInterest() public returns (uint);
    function seize(address liquidator, address borrower, uint seizeTokens) external returns (uint);


    /*** Admin Functions ***/

    function _setPendingAdmin(address payable newPendingAdmin) external returns (uint);
    function _acceptAdmin() external returns (uint);
    function _setComptroller(ComptrollerInterface newComptroller) public returns (uint);
    function _setReserveFactor(uint newReserveFactorMantissa) external returns (uint);
    function _reduceReserves(uint reduceAmount) external returns (uint);
    function _setInterestRateModel(InterestRateModel newInterestRateModel) public returns (uint);
}

contract CErc20Storage {
    /**
     * @notice Underlying asset for this CToken
     */
    address public underlying;
}

contract CErc20Interface is CErc20Storage {

    /*** User Interface ***/

    function mint(uint mintAmount) external returns (uint);
    function redeem(uint redeemTokens) external returns (uint);
    function redeemUnderlying(uint redeemAmount) external returns (uint);
    function borrow(uint borrowAmount) external returns (uint);
    function repayBorrow(uint repayAmount) external returns (uint);
    function repayBorrowBehalf(address borrower, uint repayAmount) external returns (uint);
    function liquidateBorrow(address borrower, uint repayAmount, CTokenInterface cTokenCollateral) external returns (uint);


    /*** Admin Functions ***/

    function _addReserves(uint addAmount) external returns (uint);
}

contract CEtherInterface is CErc20Storage {
    /**
     * @notice Indicator that this is a CEther contract (for inspection)
     */
    bool public constant isCEther = true;
}

contract CDelegationStorage {
    /**
     * @notice Implementation address for this contract
     */
    address public implementation;
}

contract CDelegatorInterface is CDelegationStorage {
    /**
     * @notice Emitted when implementation is changed
     */
    event NewImplementation(address oldImplementation, address newImplementation);

    /**
     * @notice Called by the admin to update the implementation of the delegator
     * @param implementation_ The address of the new implementation for delegation
     * @param allowResign Flag to indicate whether to call _resignImplementation on the old implementation
     * @param becomeImplementationData The encoded bytes data to be passed to _becomeImplementation
     */
    function _setImplementation(address implementation_, bool allowResign, bytes memory becomeImplementationData) public;
}

contract CDelegateInterface is CDelegationStorage {
    /**
     * @notice Called by the delegator on a delegate to initialize it for duty
     * @dev Should revert if any issues arise which make it unfit for delegation
     * @param data The encoded bytes data for any initialization
     */
    function _becomeImplementation(bytes memory data) public;

    /**
     * @notice Called by the delegator on a delegate to forfeit its responsibility
     */
    function _resignImplementation() public;
}

pragma solidity ^0.5.16;

interface IFuseFeeDistributor {
    function minBorrowEth() external view returns (uint256);
    function maxSupplyEth() external view returns (uint256);
    function maxUtilizationRate() external view returns (uint256);
    function interestFeeRate() external view returns (uint256);
    function () external payable;
}

pragma solidity ^0.5.16;

/**
  * @title Compound's InterestRateModel Interface
  * @author Compound
  */
contract InterestRateModel {
    /// @notice Indicator that this is an InterestRateModel contract (for inspection)
    bool public constant isInterestRateModel = true;

    /**
      * @notice Calculates the current borrow interest rate per block
      * @param cash The total amount of cash the market has
      * @param borrows The total amount of borrows the market has outstanding
      * @param reserves The total amnount of reserves the market has
      * @return The borrow rate per block (as a percentage, and scaled by 1e18)
      */
    function getBorrowRate(uint cash, uint borrows, uint reserves) external view returns (uint);

    /**
      * @notice Calculates the current supply interest rate per block
      * @param cash The total amount of cash the market has
      * @param borrows The total amount of borrows the market has outstanding
      * @param reserves The total amnount of reserves the market has
      * @param reserveFactorMantissa The current reserve factor the market has
      * @return The supply rate per block (as a percentage, and scaled by 1e18)
      */
    function getSupplyRate(uint cash, uint borrows, uint reserves, uint reserveFactorMantissa) external view returns (uint);

}