CometCore.sol

// SPDX-License-Identifier: BUSL-1.1
pragma solidity 0.8.15;

import "./CometConfiguration.sol";
import "./CometStorage.sol";
import "./CometMath.sol";

abstract contract CometCore is CometConfiguration, CometStorage, CometMath {
    struct AssetInfo {
        uint8 offset;
        address asset;
        address priceFeed;
        uint64 scale;
        uint64 borrowCollateralFactor;
        uint64 liquidateCollateralFactor;
        uint64 liquidationFactor;
        uint128 supplyCap;
    }

    /** Internal constants **/

    /// @dev The max number of assets this contract is hardcoded to support
    ///  Do not change this variable without updating all the fields throughout the contract,
    //    including the size of UserBasic.assetsIn and corresponding integer conversions.
    uint8 internal constant MAX_ASSETS = 15;

    /// @dev The max number of decimals base token can have
    ///  Note this cannot just be increased arbitrarily.
    uint8 internal constant MAX_BASE_DECIMALS = 18;

    /// @dev The max value for a collateral factor (1)
    uint64 internal constant MAX_COLLATERAL_FACTOR = FACTOR_SCALE;

    /// @dev Offsets for specific actions in the pause flag bit array
    uint8 internal constant PAUSE_SUPPLY_OFFSET = 0;
    uint8 internal constant PAUSE_TRANSFER_OFFSET = 1;
    uint8 internal constant PAUSE_WITHDRAW_OFFSET = 2;
    uint8 internal constant PAUSE_ABSORB_OFFSET = 3;
    uint8 internal constant PAUSE_BUY_OFFSET = 4;

    /// @dev The decimals required for a price feed
    uint8 internal constant PRICE_FEED_DECIMALS = 8;

    /// @dev 365 days * 24 hours * 60 minutes * 60 seconds
    uint64 internal constant SECONDS_PER_YEAR = 31_536_000;

    /// @dev The scale for base tracking accrual
    uint64 internal constant BASE_ACCRUAL_SCALE = 1e6;

    /// @dev The scale for base index (depends on time/rate scales, not base token)
    uint64 internal constant BASE_INDEX_SCALE = 1e15;

    /// @dev The scale for prices (in USD)
    uint64 internal constant PRICE_SCALE = uint64(10 ** PRICE_FEED_DECIMALS);

    /// @dev The scale for factors
    uint64 internal constant FACTOR_SCALE = 1e18;

    /// @dev The storage slot for reentrancy guard flags
    bytes32 internal constant REENTRANCY_GUARD_FLAG_SLOT = bytes32(keccak256("comet.reentrancy.guard"));

    /// @dev The reentrancy guard statuses
    uint256 internal constant REENTRANCY_GUARD_NOT_ENTERED = 0;
    uint256 internal constant REENTRANCY_GUARD_ENTERED = 1;

    /**
     * @notice Determine if the manager has permission to act on behalf of the owner
     * @param owner The owner account
     * @param manager The manager account
     * @return Whether or not the manager has permission
     */
    function hasPermission(address owner, address manager) public view returns (bool) {
        return owner == manager || isAllowed[owner][manager];
    }

    /**
     * @dev The positive present supply balance if positive or the negative borrow balance if negative
     */
    function presentValue(int104 principalValue_) internal view returns (int256) {
        if (principalValue_ >= 0) {
            return signed256(presentValueSupply(baseSupplyIndex, uint104(principalValue_)));
        } else {
            return -signed256(presentValueBorrow(baseBorrowIndex, uint104(-principalValue_)));
        }
    }

    /**
     * @dev The principal amount projected forward by the supply index
     */
    function presentValueSupply(uint64 baseSupplyIndex_, uint104 principalValue_) internal pure returns (uint256) {
        return uint256(principalValue_) * baseSupplyIndex_ / BASE_INDEX_SCALE;
    }

    /**
     * @dev The principal amount projected forward by the borrow index
     */
    function presentValueBorrow(uint64 baseBorrowIndex_, uint104 principalValue_) internal pure returns (uint256) {
        return uint256(principalValue_) * baseBorrowIndex_ / BASE_INDEX_SCALE;
    }

    /**
     * @dev The positive principal if positive or the negative principal if negative
     */
    function principalValue(int256 presentValue_) internal view returns (int104) {
        if (presentValue_ >= 0) {
            return signed104(principalValueSupply(baseSupplyIndex, uint256(presentValue_)));
        } else {
            return -signed104(principalValueBorrow(baseBorrowIndex, uint256(-presentValue_)));
        }
    }

    /**
     * @dev The present value projected backward by the supply index (rounded down)
     *  Note: This will overflow (revert) at 2^104/1e18=~20 trillion principal for assets with 18 decimals.
     */
    function principalValueSupply(uint64 baseSupplyIndex_, uint256 presentValue_) internal pure returns (uint104) {
        return safe104((presentValue_ * BASE_INDEX_SCALE) / baseSupplyIndex_);
    }

    /**
     * @dev The present value projected backward by the borrow index (rounded up)
     *  Note: This will overflow (revert) at 2^104/1e18=~20 trillion principal for assets with 18 decimals.
     */
    function principalValueBorrow(uint64 baseBorrowIndex_, uint256 presentValue_) internal pure returns (uint104) {
        return safe104((presentValue_ * BASE_INDEX_SCALE + baseBorrowIndex_ - 1) / baseBorrowIndex_);
    }
}