Contract Address Details

// SPDX-License-Identifier: MIXED

// File @openzeppelin/contracts/utils/Context.sol@v3.4.2
// License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File @openzeppelin/contracts/access/Ownable.sol@v3.4.2
// License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File @openzeppelin/contracts/math/SafeMath.sol@v3.4.2
// License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) return (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}

// File @openzeppelin/contracts/utils/EnumerableSet.sol@v3.4.2
// License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// File @openzeppelin/contracts/utils/ReentrancyGuard.sol@v3.4.2
// License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor () internal {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File contracts/interfaces/IERC20.sol
// License-Identifier: MIT
pragma solidity 0.6.12;

interface IERC20 {
    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    // EIP 2612
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

// File contracts/MasterChefVoltV3.sol
// License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;





interface IMasterChef {
    struct UserInfo {
        uint256 amount; // How many LP tokens the user has provided.
        uint256 rewardDebt; // Reward debt. See explanation below.
    }

    struct PoolInfo {
        IERC20 lpToken; // Address of LP token contract.
        uint256 allocPoint; // How many allocation points assigned to this pool. VOLT to distribute per block.
        uint256 lastRewardTimestamp; // Last block number that VOLT distribution occurs.
        uint256 accVoltPerShare; // Accumulated VOLT per share, times 1e12. See below.
    }

    function poolInfo(uint256 pid) external view returns (IMasterChef.PoolInfo memory);

    function totalAllocPoint() external view returns (uint256);

    function voltPerSec() external view returns (uint256);

    function deposit(uint256 _pid, uint256 _amount) external;

    function devPercent() external view returns (uint256);

    function treasuryPercent() external view returns (uint256);

    function investorPercent() external view returns (uint256);
}

interface IRewarder {
    function onVoltReward(address user, uint256 newLpAmount) external;

    function pendingTokens(address user) external view returns (uint256 pending);

    function rewardToken() external view returns (IERC20);
}

library BoringERC20 {
    bytes4 private constant SIG_SYMBOL = 0x95d89b41; // symbol()
    bytes4 private constant SIG_NAME = 0x06fdde03; // name()
    bytes4 private constant SIG_DECIMALS = 0x313ce567; // decimals()
    bytes4 private constant SIG_TRANSFER = 0xa9059cbb; // transfer(address,uint256)
    bytes4 private constant SIG_TRANSFER_FROM = 0x23b872dd; // transferFrom(address,address,uint256)

    function returnDataToString(bytes memory data) internal pure returns (string memory) {
        if (data.length >= 64) {
            return abi.decode(data, (string));
        } else if (data.length == 32) {
            uint8 i = 0;
            while (i < 32 && data[i] != 0) {
                i++;
            }
            bytes memory bytesArray = new bytes(i);
            for (i = 0; i < 32 && data[i] != 0; i++) {
                bytesArray[i] = data[i];
            }
            return string(bytesArray);
        } else {
            return "???";
        }
    }

    /// @notice Provides a safe ERC20.symbol version which returns '???' as fallback string.
    /// @param token The address of the ERC-20 token contract.
    /// @return (string) Token symbol.
    function safeSymbol(IERC20 token) internal view returns (string memory) {
        (bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_SYMBOL));
        return success ? returnDataToString(data) : "???";
    }

    /// @notice Provides a safe ERC20.name version which returns '???' as fallback string.
    /// @param token The address of the ERC-20 token contract.
    /// @return (string) Token name.
    function safeName(IERC20 token) internal view returns (string memory) {
        (bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_NAME));
        return success ? returnDataToString(data) : "???";
    }

    /// @notice Provides a safe ERC20.decimals version which returns '18' as fallback value.
    /// @param token The address of the ERC-20 token contract.
    /// @return (uint8) Token decimals.
    function safeDecimals(IERC20 token) internal view returns (uint8) {
        (bool success, bytes memory data) = address(token).staticcall(abi.encodeWithSelector(SIG_DECIMALS));
        return success && data.length == 32 ? abi.decode(data, (uint8)) : 18;
    }

    /// @notice Provides a safe ERC20.transfer version for different ERC-20 implementations.
    /// Reverts on a failed transfer.
    /// @param token The address of the ERC-20 token.
    /// @param to Transfer tokens to.
    /// @param amount The token amount.
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 amount
    ) internal {
        (bool success, bytes memory data) = address(token).call(abi.encodeWithSelector(SIG_TRANSFER, to, amount));
        require(success && (data.length == 0 || abi.decode(data, (bool))), "BoringERC20: Transfer failed");
    }

    /// @notice Provides a safe ERC20.transferFrom version for different ERC-20 implementations.
    /// Reverts on a failed transfer.
    /// @param token The address of the ERC-20 token.
    /// @param from Transfer tokens from.
    /// @param to Transfer tokens to.
    /// @param amount The token amount.
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 amount
    ) internal {
        (bool success, bytes memory data) = address(token).call(
            abi.encodeWithSelector(SIG_TRANSFER_FROM, from, to, amount)
        );
        require(success && (data.length == 0 || abi.decode(data, (bool))), "BoringERC20: TransferFrom failed");
    }
}

/// @notice The (older) MasterChefVoltV2 contract gives out a constant number of VOLT tokens per block.
/// It is the only address with minting rights for VOLT.
/// The idea for this MasterChefVoltV3 (MCJV3) contract is therefore to be the owner of a dummy token
/// that is deposited into the MasterChefVoltV2 (MCJV2) contract.
/// The allocation point for this pool on MCJV3 is the total allocation point for all pools that receive double incentives.
contract MasterChefVoltV3 is Ownable, ReentrancyGuard {
    using SafeMath for uint256;
    using BoringERC20 for IERC20;
    using EnumerableSet for EnumerableSet.AddressSet;

    /// @notice Info of each MCJV3 user.
    /// `amount` LP token amount the user has provided.
    /// `rewardDebt` The amount of VOLT entitled to the user.
    struct UserInfo {
        uint256 amount;
        uint256 rewardDebt;
    }

    /// @notice Info of each MCJV3 pool.
    /// `allocPoint` The amount of allocation points assigned to the pool.
    /// Also known as the amount of VOLT to distribute per block.
    struct PoolInfo {
        IERC20 lpToken;
        uint256 accVoltPerShare;
        uint256 lastRewardTimestamp;
        uint256 allocPoint;
        IRewarder rewarder;
    }

    /// @notice Address of MCJV2 contract.
    IMasterChef public immutable MASTER_CHEF_V2;
    /// @notice Address of VOLT contract.
    IERC20 public immutable VOLT;
    /// @notice The index of MCJV3 master pool in MCJV2
    uint256 public immutable MASTER_PID;
    /// @notice Info of each MCJV3 pool.
    PoolInfo[] public poolInfo;
    // Set of all LP tokens that have been added as pools
    EnumerableSet.AddressSet private lpTokens;
    /// @notice Info of each user that stakes LP tokens.
    mapping(uint256 => mapping(address => UserInfo)) public userInfo;
    /// @dev Total allocation points. Must be the sum of all allocation points in all pools.
    uint256 public totalAllocPoint;
    uint256 private constant ACC_TOKEN_PRECISION = 1e18;

    event Add(uint256 indexed pid, uint256 allocPoint, IERC20 indexed lpToken, IRewarder indexed rewarder);
    event Set(uint256 indexed pid, uint256 allocPoint, IRewarder indexed rewarder, bool overwrite);
    event Deposit(address indexed user, uint256 indexed pid, uint256 amount);
    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event UpdatePool(uint256 indexed pid, uint256 lastRewardTimestamp, uint256 lpSupply, uint256 accVoltPerShare);
    event Harvest(address indexed user, uint256 indexed pid, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event Init();

    /// @param _MASTER_CHEF_V2 The VoltSwap MCJV2 contract address.
    /// @param _volt The VOLT token contract address.
    /// @param _MASTER_PID The pool ID of the dummy token on the base MCJV2 contract.
    constructor(
        IMasterChef _MASTER_CHEF_V2,
        IERC20 _volt,
        uint256 _MASTER_PID
    ) public {
        MASTER_CHEF_V2 = _MASTER_CHEF_V2;
        VOLT = _volt;
        MASTER_PID = _MASTER_PID;
    }

    /// @notice Deposits a dummy token to `MASTER_CHEF_V2` MCJV2. This is required because MCJV2 holds the minting rights for VOLT.
    /// Any balance of transaction sender in `dummyToken` is transferred.
    /// The allocation point for the pool on MCJV2 is the total allocation point for all pools that receive double incentives.
    /// @param dummyToken The address of the ERC-20 token to deposit into MCJV2.
    function init(IERC20 dummyToken) external onlyOwner {
        uint256 balance = dummyToken.balanceOf(msg.sender);
        require(balance != 0, "MasterChefV2: Balance must exceed 0");
        dummyToken.safeTransferFrom(msg.sender, address(this), balance);
        dummyToken.approve(address(MASTER_CHEF_V2), balance);
        MASTER_CHEF_V2.deposit(MASTER_PID, balance);
        emit Init();
    }

    /// @notice Returns the number of MCJV3 pools.
    function poolLength() external view returns (uint256 pools) {
        pools = poolInfo.length;
    }

    /// @notice Add a new LP to the pool. Can only be called by the owner.
    /// DO NOT add the same LP token more than once. Rewards will be messed up if you do.
    /// @param allocPoint AP of the new pool.
    /// @param _lpToken Address of the LP ERC-20 token.
    /// @param _rewarder Address of the rewarder delegate.
    function add(
        uint256 allocPoint,
        IERC20 _lpToken,
        IRewarder _rewarder
    ) external onlyOwner {
        require(!lpTokens.contains(address(_lpToken)), "add: LP already added");
        // Sanity check to ensure _lpToken is an ERC20 token
        _lpToken.balanceOf(address(this));
        // Sanity check if we add a rewarder
        if (address(_rewarder) != address(0)) {
            _rewarder.onVoltReward(address(0), 0);
        }

        uint256 lastRewardTimestamp = block.timestamp;
        totalAllocPoint = totalAllocPoint.add(allocPoint);

        poolInfo.push(
            PoolInfo({
                lpToken: _lpToken,
                allocPoint: allocPoint,
                lastRewardTimestamp: lastRewardTimestamp,
                accVoltPerShare: 0,
                rewarder: _rewarder
            })
        );
        lpTokens.add(address(_lpToken));
        emit Add(poolInfo.length.sub(1), allocPoint, _lpToken, _rewarder);
    }

    /// @notice Update the given pool's VOLT allocation point and `IRewarder` contract. Can only be called by the owner.
    /// @param _pid The index of the pool. See `poolInfo`.
    /// @param _allocPoint New AP of the pool.
    /// @param _rewarder Address of the rewarder delegate.
    /// @param overwrite True if _rewarder should be `set`. Otherwise `_rewarder` is ignored.
    function set(
        uint256 _pid,
        uint256 _allocPoint,
        IRewarder _rewarder,
        bool overwrite
    ) external onlyOwner {
        PoolInfo memory pool = poolInfo[_pid];
        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);
        pool.allocPoint = _allocPoint;
        if (overwrite) {
            _rewarder.onVoltReward(address(0), 0); // sanity check
            pool.rewarder = _rewarder;
        }
        poolInfo[_pid] = pool;
        emit Set(_pid, _allocPoint, overwrite ? _rewarder : pool.rewarder, overwrite);
    }

    /// @notice View function to see pending VOLT on frontend.
    /// @param _pid The index of the pool. See `poolInfo`.
    /// @param _user Address of user.
    /// @return pendingVolt VOLT reward for a given user.
    //          bonusTokenAddress The address of the bonus reward.
    //          bonusTokenSymbol The symbol of the bonus token.
    //          pendingBonusToken The amount of bonus rewards pending.
    function pendingTokens(uint256 _pid, address _user)
        external
        view
        returns (
            uint256 pendingVolt,
            address bonusTokenAddress,
            string memory bonusTokenSymbol,
            uint256 pendingBonusToken
        )
    {
        PoolInfo memory pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][_user];
        uint256 accVoltPerShare = pool.accVoltPerShare;
        uint256 lpSupply = pool.lpToken.balanceOf(address(this));
        if (block.timestamp > pool.lastRewardTimestamp && lpSupply != 0) {
            uint256 secondsElapsed = block.timestamp.sub(pool.lastRewardTimestamp);
            uint256 voltReward = secondsElapsed.mul(voltPerSec()).mul(pool.allocPoint).div(totalAllocPoint);
            accVoltPerShare = accVoltPerShare.add(voltReward.mul(ACC_TOKEN_PRECISION).div(lpSupply));
        }
        pendingVolt = user.amount.mul(accVoltPerShare).div(ACC_TOKEN_PRECISION).sub(user.rewardDebt);

        // If it's a double reward farm, we return info about the bonus token
        if (address(pool.rewarder) != address(0)) {
            bonusTokenAddress = address(pool.rewarder.rewardToken());
            bonusTokenSymbol = IERC20(pool.rewarder.rewardToken()).safeSymbol();
            pendingBonusToken = pool.rewarder.pendingTokens(_user);
        }
    }

    /// @notice Update reward variables for all pools. Be careful of gas spending!
    /// @param pids Pool IDs of all to be updated. Make sure to update all active pools.
    function massUpdatePools(uint256[] calldata pids) external {
        uint256 len = pids.length;
        for (uint256 i = 0; i < len; ++i) {
            updatePool(pids[i]);
        }
    }

    /// @notice Calculates and returns the `amount` of VOLT per block.
    function voltPerSec() public view returns (uint256 amount) {
        uint256 total = 1000;
        uint256 lpPercent = total.sub(MASTER_CHEF_V2.devPercent()).sub(MASTER_CHEF_V2.treasuryPercent()).sub(
            MASTER_CHEF_V2.investorPercent()
        );
        uint256 lpShare = MASTER_CHEF_V2.voltPerSec().mul(lpPercent).div(total);
        amount = lpShare.mul(MASTER_CHEF_V2.poolInfo(MASTER_PID).allocPoint).div(MASTER_CHEF_V2.totalAllocPoint());
    }

    /// @notice Update reward variables of the given pool.
    /// @param pid The index of the pool. See `poolInfo`.
    function updatePool(uint256 pid) public {
        PoolInfo memory pool = poolInfo[pid];
        if (block.timestamp > pool.lastRewardTimestamp) {
            uint256 lpSupply = pool.lpToken.balanceOf(address(this));
            if (lpSupply > 0) {
                uint256 secondsElapsed = block.timestamp.sub(pool.lastRewardTimestamp);
                uint256 voltReward = secondsElapsed.mul(voltPerSec()).mul(pool.allocPoint).div(totalAllocPoint);
                pool.accVoltPerShare = pool.accVoltPerShare.add((voltReward.mul(ACC_TOKEN_PRECISION).div(lpSupply)));
            }
            pool.lastRewardTimestamp = block.timestamp;
            poolInfo[pid] = pool;
            emit UpdatePool(pid, pool.lastRewardTimestamp, lpSupply, pool.accVoltPerShare);
        }
    }

    /// @notice Deposit LP tokens to MCJV3 for VOLT allocation.
    /// @param pid The index of the pool. See `poolInfo`.
    /// @param amount LP token amount to deposit.
    function deposit(uint256 pid, uint256 amount) external nonReentrant {
        harvestFromMasterChef();
        updatePool(pid);
        PoolInfo memory pool = poolInfo[pid];
        UserInfo storage user = userInfo[pid][msg.sender];

        if (user.amount > 0) {
            // Harvest VOLT
            uint256 pending = user.amount.mul(pool.accVoltPerShare).div(ACC_TOKEN_PRECISION).sub(user.rewardDebt);
            VOLT.safeTransfer(msg.sender, pending);
            emit Harvest(msg.sender, pid, pending);
        }

        uint256 balanceBefore = pool.lpToken.balanceOf(address(this));
        pool.lpToken.safeTransferFrom(msg.sender, address(this), amount);
        uint256 receivedAmount = pool.lpToken.balanceOf(address(this)).sub(balanceBefore);

        // Effects
        user.amount = user.amount.add(receivedAmount);
        user.rewardDebt = user.amount.mul(pool.accVoltPerShare).div(ACC_TOKEN_PRECISION);

        // Interactions
        IRewarder _rewarder = pool.rewarder;
        if (address(_rewarder) != address(0)) {
            _rewarder.onVoltReward(msg.sender, user.amount);
        }

        emit Deposit(msg.sender, pid, receivedAmount);
    }

    /// @notice Withdraw LP tokens from MCJV3.
    /// @param pid The index of the pool. See `poolInfo`.
    /// @param amount LP token amount to withdraw.
    function withdraw(uint256 pid, uint256 amount) external nonReentrant {
        harvestFromMasterChef();
        updatePool(pid);
        PoolInfo memory pool = poolInfo[pid];
        UserInfo storage user = userInfo[pid][msg.sender];

        if (user.amount > 0) {
            // Harvest VOLT
            uint256 pending = user.amount.mul(pool.accVoltPerShare).div(ACC_TOKEN_PRECISION).sub(user.rewardDebt);
            VOLT.safeTransfer(msg.sender, pending);
            emit Harvest(msg.sender, pid, pending);
        }

        // Effects
        user.amount = user.amount.sub(amount);
        user.rewardDebt = user.amount.mul(pool.accVoltPerShare).div(ACC_TOKEN_PRECISION);

        // Interactions
        IRewarder _rewarder = pool.rewarder;
        if (address(_rewarder) != address(0)) {
            _rewarder.onVoltReward(msg.sender, user.amount);
        }

        pool.lpToken.safeTransfer(msg.sender, amount);

        emit Withdraw(msg.sender, pid, amount);
    }

    /// @notice Harvests VOLT from `MASTER_CHEF_V2` MCJV2 and pool `MASTER_PID` to this MCJV3 contract.
    function harvestFromMasterChef() public {
        MASTER_CHEF_V2.deposit(MASTER_PID, 0);
    }

    /// @notice Withdraw without caring about rewards. EMERGENCY ONLY.
    /// @param pid The index of the pool. See `poolInfo`.
    function emergencyWithdraw(uint256 pid) external nonReentrant {
        PoolInfo memory pool = poolInfo[pid];
        UserInfo storage user = userInfo[pid][msg.sender];
        uint256 amount = user.amount;
        user.amount = 0;
        user.rewardDebt = 0;

        IRewarder _rewarder = pool.rewarder;
        if (address(_rewarder) != address(0)) {
            _rewarder.onVoltReward(msg.sender, 0);
        }

        // Note: transfer can fail or succeed if `amount` is zero.
        pool.lpToken.safeTransfer(msg.sender, amount);
        emit EmergencyWithdraw(msg.sender, pid, amount);
    }
}