ETH Price: $3,153.31 (+3.30%)

Contract

0xb3C68a491608952Cb1257FC9909a537a0173b63B
 
Transaction Hash
Method
Block
From
To
Value
Swap And Send1190190072024-04-20 18:13:117 hrs ago1713636791IN
Hop Protocol: DAI Wrapper
0 ETH0.000002220.01033417
Swap And Send1190134552024-04-20 15:08:0710 hrs ago1713625687IN
Hop Protocol: DAI Wrapper
0 ETH0.000002470.01150578
Swap And Send1190050552024-04-20 10:28:0715 hrs ago1713608887IN
Hop Protocol: DAI Wrapper
0 ETH0.000002190.0102216
Swap And Send1190015832024-04-20 8:32:2317 hrs ago1713601943IN
Hop Protocol: DAI Wrapper
0 ETH0.00000350.01604744
Swap And Send1189643572024-04-19 11:51:3138 hrs ago1713527491IN
Hop Protocol: DAI Wrapper
0 ETH0.000015370.0714488
Swap And Send1189591422024-04-19 8:57:4140 hrs ago1713517061IN
Hop Protocol: DAI Wrapper
0 ETH0.000008340.03824691
Swap And Send1189261852024-04-18 14:39:072 days ago1713451147IN
Hop Protocol: DAI Wrapper
0 ETH0.0000130.06041563
Swap And Send1188821922024-04-17 14:12:413 days ago1713363161IN
Hop Protocol: DAI Wrapper
0 ETH0.000013110.06107153
Swap And Send1188383632024-04-16 13:51:434 days ago1713275503IN
Hop Protocol: DAI Wrapper
0 ETH0.000016910.0785671
Swap And Send1188382432024-04-16 13:47:434 days ago1713275263IN
Hop Protocol: DAI Wrapper
0 ETH0.000019730.0916663
Swap And Send1188381012024-04-16 13:42:594 days ago1713274979IN
Hop Protocol: DAI Wrapper
0 ETH0.000016170.0741177
Swap And Send1188380952024-04-16 13:42:474 days ago1713274967IN
Hop Protocol: DAI Wrapper
0 ETH0.000016440.0741815
Swap And Send1188015442024-04-15 17:24:255 days ago1713201865IN
Hop Protocol: DAI Wrapper
0 ETH0.000013410.0614561
Swap And Send1187707242024-04-15 0:17:056 days ago1713140225IN
Hop Protocol: DAI Wrapper
0 ETH0.000013540.06205332
Swap And Send1187683592024-04-14 22:58:156 days ago1713135495IN
Hop Protocol: DAI Wrapper
0 ETH0.000012850.05986491
Swap And Send1187660012024-04-14 21:39:396 days ago1713130779IN
Hop Protocol: DAI Wrapper
0 ETH0.000012850.06013606
Swap And Send1187526382024-04-14 14:14:136 days ago1713104053IN
Hop Protocol: DAI Wrapper
0 ETH0.000013020.0600524
Swap And Send1187503672024-04-14 12:58:316 days ago1713099511IN
Hop Protocol: DAI Wrapper
0 ETH0.00001310.0604335
Swap And Send1186585262024-04-12 9:57:098 days ago1712915829IN
Hop Protocol: DAI Wrapper
0 ETH0.00001330.0609056
Swap And Send1186514082024-04-12 5:59:538 days ago1712901593IN
Hop Protocol: DAI Wrapper
0 ETH0.000013220.06143566
Swap And Send1186308402024-04-11 18:34:179 days ago1712860457IN
Hop Protocol: DAI Wrapper
0 ETH0.000013140.06111429
Swap And Send1185955102024-04-10 22:56:3710 days ago1712789797IN
Hop Protocol: DAI Wrapper
0 ETH0.000013170.06035401
Swap And Send1185889522024-04-10 19:18:0110 days ago1712776681IN
Hop Protocol: DAI Wrapper
0 ETH0.000013350.06206054
Swap And Send1185874332024-04-10 18:27:2310 days ago1712773643IN
Hop Protocol: DAI Wrapper
0 ETH0.000013130.06115761
Swap And Send1185819472024-04-10 15:24:3110 days ago1712762671IN
Hop Protocol: DAI Wrapper
0 ETH0.000013330.0606181
View all transactions

Latest 25 internal transactions (View All)

Advanced mode:
Parent Txn Hash Block From To Value
1075576122023-07-30 10:46:41265 days ago1690714001
Hop Protocol: DAI Wrapper
0 ETH
1075576122023-07-30 10:46:41265 days ago1690714001
Hop Protocol: DAI Wrapper
0 ETH
1075576122023-07-30 10:46:41265 days ago1690714001
Hop Protocol: DAI Wrapper
0 ETH
1075576122023-07-30 10:46:41265 days ago1690714001
Hop Protocol: DAI Wrapper
0 ETH
1075576122023-07-30 10:46:41265 days ago1690714001
Hop Protocol: DAI Wrapper
0 ETH
1075568732023-07-30 10:22:03265 days ago1690712523
Hop Protocol: DAI Wrapper
0 ETH
1075568732023-07-30 10:22:03265 days ago1690712523
Hop Protocol: DAI Wrapper
0 ETH
1075568732023-07-30 10:22:03265 days ago1690712523
Hop Protocol: DAI Wrapper
0 ETH
1075568732023-07-30 10:22:03265 days ago1690712523
Hop Protocol: DAI Wrapper
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1075568732023-07-30 10:22:03265 days ago1690712523
Hop Protocol: DAI Wrapper
0 ETH
1075553752023-07-30 9:32:07265 days ago1690709527
Hop Protocol: DAI Wrapper
0 ETH
1075553752023-07-30 9:32:07265 days ago1690709527
Hop Protocol: DAI Wrapper
0 ETH
1075553752023-07-30 9:32:07265 days ago1690709527
Hop Protocol: DAI Wrapper
0 ETH
1075553752023-07-30 9:32:07265 days ago1690709527
Hop Protocol: DAI Wrapper
0 ETH
1075553752023-07-30 9:32:07265 days ago1690709527
Hop Protocol: DAI Wrapper
0 ETH
1075551552023-07-30 9:24:47265 days ago1690709087
Hop Protocol: DAI Wrapper
0 ETH
1075551552023-07-30 9:24:47265 days ago1690709087
Hop Protocol: DAI Wrapper
0 ETH
1075551552023-07-30 9:24:47265 days ago1690709087
Hop Protocol: DAI Wrapper
0 ETH
1075551552023-07-30 9:24:47265 days ago1690709087
Hop Protocol: DAI Wrapper
0 ETH
1075551552023-07-30 9:24:47265 days ago1690709087
Hop Protocol: DAI Wrapper
0 ETH
1075551272023-07-30 9:23:51265 days ago1690709031
Hop Protocol: DAI Wrapper
0 ETH
1075551272023-07-30 9:23:51265 days ago1690709031
Hop Protocol: DAI Wrapper
0 ETH
1075551272023-07-30 9:23:51265 days ago1690709031
Hop Protocol: DAI Wrapper
0 ETH
1075551272023-07-30 9:23:51265 days ago1690709031
Hop Protocol: DAI Wrapper
0 ETH
1075551272023-07-30 9:23:51265 days ago1690709031
Hop Protocol: DAI Wrapper
0 ETH
View All Internal Transactions

Latest 25 Deposits

L2 Txn Hash L1 Deposit Txn Value Token
0x0217e4635756f61ecc98ea16b4e8a59e3fee0566e872b34873b8452d7fd030a22024-04-14 19:23:036 days ago17131225832,000 DAI Hop Toke... (hDAI)
0x0217e4635756f61ecc98ea16b4e8a59e3fee0566e872b34873b8452d7fd030a22024-04-14 19:23:036 days ago17131225831,996.365031120272045614 Dai Stableco... (DAI)
0x93e45030820fd433c130418f07154209592e56a34d7d23420ca9790f26bf06bf2024-04-14 13:58:196 days ago17131030992,993.272515304289456419 Dai Stableco... (DAI)
0x93e45030820fd433c130418f07154209592e56a34d7d23420ca9790f26bf06bf2024-04-14 13:58:196 days ago17131030993,000 DAI Hop Toke... (hDAI)
0x6eebef14d216bb0d61b4a8d898492c0f9388fd7ed039a8cb3c10cdeb3e98c8232024-04-14 9:47:476 days ago17130880675,987.754820703042038298 Dai Stableco... (DAI)
0x6eebef14d216bb0d61b4a8d898492c0f9388fd7ed039a8cb3c10cdeb3e98c8232024-04-14 9:47:476 days ago17130880676,000 DAI Hop Toke... (hDAI)
0xb781637a6b576e9d9aed7f50fb37f19ffa37c6f9aca9e75c570a6fae5243eba22024-04-14 3:49:016 days ago1713066541772.632957492101466219 DAI Hop Toke... (hDAI)
0xb781637a6b576e9d9aed7f50fb37f19ffa37c6f9aca9e75c570a6fae5243eba22024-04-14 3:49:016 days ago1713066541771.177224696530314182 Dai Stableco... (DAI)
0x9b00cff52a90fed2c2ccd49846b129bd65b4e6e210fe410f5687d6d0d46278a42024-04-12 8:31:478 days ago171291070725,003.224457705400327096 Dai Stableco... (DAI)
0x9b00cff52a90fed2c2ccd49846b129bd65b4e6e210fe410f5687d6d0d46278a42024-04-12 8:31:478 days ago171291070725,000 DAI Hop Toke... (hDAI)
0xe49ea2d34d8036a1396b973f3bc78b2ae2ab649c1a1644b638d864ae0858e8ad2024-04-05 18:00:0915 days ago17123400095,276.689944070637878684 DAI Hop Toke... (hDAI)
0xe49ea2d34d8036a1396b973f3bc78b2ae2ab649c1a1644b638d864ae0858e8ad2024-04-05 18:00:0915 days ago17123400095,278.235428875935169304 Dai Stableco... (DAI)
0xa57350791a3290b42305e5c03b213a5e8e5a26b6e5e4ec2d9d8db897f98114a42024-04-05 8:06:5915 days ago171230441912,004.388196101278171621 Dai Stableco... (DAI)
0xa57350791a3290b42305e5c03b213a5e8e5a26b6e5e4ec2d9d8db897f98114a42024-04-05 8:06:5915 days ago171230441912,000 DAI Hop Toke... (hDAI)
0xc6ee036c9b426192cafc12dbd318164edbf0ae25156c7aaa299e895a4f5ca2372024-04-04 0:08:1517 days ago17121892953,025.686612425724762808 DAI Hop Toke... (hDAI)
0xc6ee036c9b426192cafc12dbd318164edbf0ae25156c7aaa299e895a4f5ca2372024-04-04 0:08:1517 days ago17121892953,025.239617767543059028 Dai Stableco... (DAI)
0xf95eda47fa793f4ef91586cb843fb94a662e8e4f7d4936ae59d1cfec331705f42024-03-25 8:19:3726 days ago171135477749,999.470246261815833829 Dai Stableco... (DAI)
0xf95eda47fa793f4ef91586cb843fb94a662e8e4f7d4936ae59d1cfec331705f42024-03-25 8:19:3726 days ago171135477750,000 DAI Hop Toke... (hDAI)
0x0ec20c8b464e2fbc3a75dbbf5ef9d454c4bd7082da3d66edcabfa682de0901b72024-03-25 0:16:0927 days ago17113257698,796.322599886187238174 DAI Hop Toke... (hDAI)
0x0ec20c8b464e2fbc3a75dbbf5ef9d454c4bd7082da3d66edcabfa682de0901b72024-03-25 0:16:0927 days ago17113257698,806.208712968779195507 Dai Stableco... (DAI)
0x9f8cac1fb7af38e917ff9def5af69b16a90d0509ad4812e1e0b1c3cc16eacb2a2024-03-24 14:36:1327 days ago1711290973109.086042678299984407 Dai Stableco... (DAI)
0x9f8cac1fb7af38e917ff9def5af69b16a90d0509ad4812e1e0b1c3cc16eacb2a2024-03-24 14:36:1327 days ago1711290973108.95634345151772 DAI Hop Toke... (hDAI)
0x5a4cdc275ac4fdb76cded88c11e1e89ed89bfe642957b929d746709dca12cfc22024-03-22 12:40:5329 days ago17111112534,828.965312306374942462 Dai Stableco... (DAI)
0x5a4cdc275ac4fdb76cded88c11e1e89ed89bfe642957b929d746709dca12cfc22024-03-22 12:40:5329 days ago17111112534,825 DAI Hop Toke... (hDAI)
0x976a59480c0fa441d1f401a884f2cd50c9b0f7492b1bf6af62a213a097c2fd892024-03-22 2:59:2729 days ago17110763671,000.1500225033755 DAI Hop Toke... (hDAI)
View All Deposits

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Contract Source Code Verified (Exact Match)

Contract Name:
L2_AmmWrapper

Compiler Version
v0.6.12

Optimization Enabled:
Yes with 1 runs

Other Settings:
default evmVersion

Contract Source Code (Solidity Standard Json-Input format)

File 1 of 72 : L2_AmmWrapper.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "../saddle/Swap.sol";
import "./L2_Bridge.sol";
import "../interfaces/IWETH.sol";

contract L2_AmmWrapper {

    L2_Bridge public immutable bridge;
    IERC20 public immutable l2CanonicalToken;
    bool public immutable l2CanonicalTokenIsEth;
    IERC20 public immutable hToken;
    Swap public immutable exchangeAddress;

    /// @notice When l2CanonicalTokenIsEth is true, l2CanonicalToken should be set to the WETH address
    constructor(
        L2_Bridge _bridge,
        IERC20 _l2CanonicalToken,
        bool _l2CanonicalTokenIsEth,
        IERC20 _hToken,
        Swap _exchangeAddress
    )
        public
    {
        bridge = _bridge;
        l2CanonicalToken = _l2CanonicalToken;
        l2CanonicalTokenIsEth = _l2CanonicalTokenIsEth;
        hToken = _hToken;
        exchangeAddress = _exchangeAddress;
    }

    receive() external payable {}

    /// @notice amount is the amount the user wants to send plus the Bonder fee
    function swapAndSend(
        uint256 chainId,
        address recipient,
        uint256 amount,
        uint256 bonderFee,
        uint256 amountOutMin,
        uint256 deadline,
        uint256 destinationAmountOutMin,
        uint256 destinationDeadline
    )
        public
        payable
    {
        require(amount >= bonderFee, "L2_AMM_W: Bonder fee cannot exceed amount");

        if (l2CanonicalTokenIsEth) {
            require(msg.value == amount, "L2_AMM_W: Value does not match amount");
            IWETH(address(l2CanonicalToken)).deposit{value: amount}();
        } else {
            require(l2CanonicalToken.transferFrom(msg.sender, address(this), amount), "L2_AMM_W: TransferFrom failed");
        }

        require(l2CanonicalToken.approve(address(exchangeAddress), amount), "L2_AMM_W: Approve failed");
        uint256 swapAmount = Swap(exchangeAddress).swap(
            0,
            1,
            amount,
            amountOutMin,
            deadline
        );

        bridge.send(chainId, recipient, swapAmount, bonderFee, destinationAmountOutMin, destinationDeadline);
    }

    function attemptSwap(
        address recipient,
        uint256 amount,
        uint256 amountOutMin,
        uint256 deadline
    )
        external
    {
        require(hToken.transferFrom(msg.sender, address(this), amount), "L2_AMM_W: TransferFrom failed");
        require(hToken.approve(address(exchangeAddress), amount), "L2_AMM_W: Approve failed");

        uint256 amountOut = 0;
        try Swap(exchangeAddress).swap(
            1,
            0,
            amount,
            amountOutMin,
            deadline
        ) returns (uint256 _amountOut) {
            amountOut = _amountOut;
        } catch {}

        if (amountOut == 0) {
            // Transfer hToken to recipient if swap fails
            require(hToken.transfer(recipient, amount), "L2_AMM_W: Transfer failed");
            return;
        }

        if (l2CanonicalTokenIsEth) {
            IWETH(address(l2CanonicalToken)).withdraw(amountOut);
            (bool success, ) = recipient.call{value: amountOut}(new bytes(0));
            require(success, 'L2_AMM_W: ETH transfer failed');
        } else {
            require(l2CanonicalToken.transfer(recipient, amountOut), "L2_AMM_W: Transfer failed");
        }
    }
}

File 2 of 72 : Accounting.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";

/**
 * @dev Accounting is an abstract contract that encapsulates the most critical logic in the Hop contracts.
 * The accounting system works by using two balances that can only increase `_credit` and `_debit`.
 * A bonder's available balance is the total credit minus the total debit. The contract exposes
 * two external functions that allows a bonder to stake and unstake and exposes two internal
 * functions to its child contracts that allow the child contract to add to the credit 
 * and debit balance. In addition, child contracts can override `_additionalDebit` to account
 * for any additional debit balance in an alternative way. Lastly, it exposes a modifier,
 * `requirePositiveBalance`, that can be used by child contracts to ensure the bonder does not
 * use more than its available stake.
 */

abstract contract Accounting is ReentrancyGuard {
    using SafeMath for uint256;

    mapping(address => bool) private _isBonder;

    mapping(address => uint256) private _credit;
    mapping(address => uint256) private _debit;

    event Stake (
        address indexed account,
        uint256 amount
    );

    event Unstake (
        address indexed account,
        uint256 amount
    );

    event BonderAdded (
        address indexed newBonder
    );

    event BonderRemoved (
        address indexed previousBonder
    );

    /* ========== Modifiers ========== */

    modifier onlyBonder {
        require(_isBonder[msg.sender], "ACT: Caller is not bonder");
        _;
    }

    modifier onlyGovernance {
        _requireIsGovernance();
        _;
    }

    /// @dev Used by parent contract to ensure that the Bonder is solvent at the end of the transaction.
    modifier requirePositiveBalance {
        _;
        require(getCredit(msg.sender) >= getDebitAndAdditionalDebit(msg.sender), "ACT: Not enough available credit");
    }

    /// @dev Sets the Bonder addresses
    constructor(address[] memory bonders) public {
        for (uint256 i = 0; i < bonders.length; i++) {
            require(_isBonder[bonders[i]] == false, "ACT: Cannot add duplicate bonder");
            _isBonder[bonders[i]] = true;
            emit BonderAdded(bonders[i]);
        }
    }

    /* ========== Virtual functions ========== */
    /**
     * @dev The following functions are overridden in L1_Bridge and L2_Bridge
     */
    function _transferFromBridge(address recipient, uint256 amount) internal virtual;
    function _transferToBridge(address from, uint256 amount) internal virtual;
    function _requireIsGovernance() internal virtual;

    /**
     * @dev This function can be optionally overridden by a parent contract to track any additional
     * debit balance in an alternative way.
     */
    function _additionalDebit(address /*bonder*/) internal view virtual returns (uint256) {
        this; // Silence state mutability warning without generating any additional byte code
        return 0;
    }

    /* ========== Public/external getters ========== */

    /**
     * @dev Check if address is a Bonder
     * @param maybeBonder The address being checked
     * @return true if address is a Bonder
     */
    function getIsBonder(address maybeBonder) public view returns (bool) {
        return _isBonder[maybeBonder];
    }

    /**
     * @dev Get the Bonder's credit balance
     * @param bonder The owner of the credit balance being checked
     * @return The credit balance for the Bonder
     */
    function getCredit(address bonder) public view returns (uint256) {
        return _credit[bonder];
    }

    /**
     * @dev Gets the debit balance tracked by `_debit` and does not include `_additionalDebit()`
     * @param bonder The owner of the debit balance being checked
     * @return The debit amount for the Bonder
     */
    function getRawDebit(address bonder) external view returns (uint256) {
        return _debit[bonder];
    }

    /**
     * @dev Get the Bonder's total debit
     * @param bonder The owner of the debit balance being checked
     * @return The Bonder's total debit balance
     */
    function getDebitAndAdditionalDebit(address bonder) public view returns (uint256) {
        return _debit[bonder].add(_additionalDebit(bonder));
    }

    /* ========== Bonder external functions ========== */

    /** 
     * @dev Allows the Bonder to deposit tokens and increase its credit balance
     * @param bonder The address being staked on
     * @param amount The amount being staked
     */
    function stake(address bonder, uint256 amount) external payable nonReentrant {
        require(_isBonder[bonder] == true, "ACT: Address is not bonder");
        _transferToBridge(msg.sender, amount);
        _addCredit(bonder, amount);

        emit Stake(bonder, amount);
    }

    /**
     * @dev Allows the caller to withdraw any available balance and add to their debit balance
     * @param amount The amount being unstaked
     */
    function unstake(uint256 amount) external requirePositiveBalance nonReentrant {
        _addDebit(msg.sender, amount);
        _transferFromBridge(msg.sender, amount);

        emit Unstake(msg.sender, amount);
    }

    /**
     * @dev Add Bonder to allowlist
     * @param bonder The address being added as a Bonder
     */
    function addBonder(address bonder) external onlyGovernance {
        require(_isBonder[bonder] == false, "ACT: Address is already bonder");
        _isBonder[bonder] = true;

        emit BonderAdded(bonder);
    }

    /**
     * @dev Remove Bonder from allowlist
     * @param bonder The address being removed as a Bonder
     */
    function removeBonder(address bonder) external onlyGovernance {
        require(_isBonder[bonder] == true, "ACT: Address is not bonder");
        _isBonder[bonder] = false;

        emit BonderRemoved(bonder);
    }

    /* ========== Internal functions ========== */

    function _addCredit(address bonder, uint256 amount) internal {
        _credit[bonder] = _credit[bonder].add(amount);
    }

    function _addDebit(address bonder, uint256 amount) internal {
        _debit[bonder] = _debit[bonder].add(amount);
    }
}

File 3 of 72 : SafeMath.sol
// SPDX-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 4 of 72 : ReentrancyGuard.sol
// SPDX-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 5 of 72 : Mock_Accounting.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/Accounting.sol";

contract Mock_Accounting is Accounting {
    constructor(address[] memory _bonders) public Accounting(_bonders) {}

    function _transferFromBridge(address _recipient, uint256 _amount) internal override {}
    function _transferToBridge(address _from, uint256 _amount) internal override {}
    function _requireIsGovernance() internal override {}
}

File 6 of 72 : Bridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "./Accounting.sol";
import "../libraries/Lib_MerkleTree.sol";

/**
 * @dev Bridge extends the accounting system and encapsulates the logic that is shared by both the
 * L1 and L2 Bridges. It allows to TransferRoots to be set by parent contracts and for those
 * TransferRoots to be withdrawn against. It also allows the bonder to bond and withdraw Transfers
 * directly through `bondWithdrawal` and then settle those bonds against their TransferRoot once it
 * has been set.
 */

abstract contract Bridge is Accounting {
    using Lib_MerkleTree for bytes32;

    struct TransferRoot {
        uint256 total;
        uint256 amountWithdrawn;
        uint256 createdAt;
    }

    /* ========== Events ========== */

    event Withdrew(
        bytes32 indexed transferId,
        address indexed recipient,
        uint256 amount,
        bytes32 transferNonce
    );

    event WithdrawalBonded(
        bytes32 indexed transferId,
        uint256 amount
    );

    event WithdrawalBondSettled(
        address indexed bonder,
        bytes32 indexed transferId,
        bytes32 indexed rootHash
    );

    event MultipleWithdrawalsSettled(
        address indexed bonder,
        bytes32 indexed rootHash,
        uint256 totalBondsSettled
    );

    event TransferRootSet(
        bytes32 indexed rootHash,
        uint256 totalAmount
    );

    /* ========== State ========== */

    mapping(bytes32 => TransferRoot) private _transferRoots;
    mapping(bytes32 => bool) private _spentTransferIds;
    mapping(address => mapping(bytes32 => uint256)) private _bondedWithdrawalAmounts;

    uint256 constant RESCUE_DELAY = 8 weeks;

    constructor(address[] memory bonders) public Accounting(bonders) {}

    /* ========== Public Getters ========== */

    /**
     * @dev Get the hash that represents an individual Transfer.
     * @param chainId The id of the destination chain
     * @param recipient The address receiving the Transfer
     * @param amount The amount being transferred including the `_bonderFee`
     * @param transferNonce Used to avoid transferId collisions
     * @param bonderFee The amount paid to the address that withdraws the Transfer
     * @param amountOutMin The minimum amount received after attempting to swap in the destination
     * AMM market. 0 if no swap is intended.
     * @param deadline The deadline for swapping in the destination AMM market. 0 if no
     * swap is intended.
     */
    function getTransferId(
        uint256 chainId,
        address recipient,
        uint256 amount,
        bytes32 transferNonce,
        uint256 bonderFee,
        uint256 amountOutMin,
        uint256 deadline
    )
        public
        pure
        returns (bytes32)
    {
        return keccak256(abi.encode(
            chainId,
            recipient,
            amount,
            transferNonce,
            bonderFee,
            amountOutMin,
            deadline
        ));
    }

    /**
     * @notice getChainId can be overridden by subclasses if needed for compatibility or testing purposes.
     * @dev Get the current chainId
     * @return chainId The current chainId
     */
    function getChainId() public virtual view returns (uint256 chainId) {
        this; // Silence state mutability warning without generating any additional byte code
        assembly {
            chainId := chainid()
        }
    }

    /**
     * @dev Get the TransferRoot id for a given rootHash and totalAmount
     * @param rootHash The Merkle root of the TransferRoot
     * @param totalAmount The total of all Transfers in the TransferRoot
     * @return The calculated transferRootId
     */
    function getTransferRootId(bytes32 rootHash, uint256 totalAmount) public pure returns (bytes32) {
        return keccak256(abi.encodePacked(rootHash, totalAmount));
    }

    /**
     * @dev Get the TransferRoot for a given rootHash and totalAmount
     * @param rootHash The Merkle root of the TransferRoot
     * @param totalAmount The total of all Transfers in the TransferRoot
     * @return The TransferRoot with the calculated transferRootId
     */
    function getTransferRoot(bytes32 rootHash, uint256 totalAmount) public view returns (TransferRoot memory) {
        return _transferRoots[getTransferRootId(rootHash, totalAmount)];
    }

    /**
     * @dev Get the amount bonded for the withdrawal of a transfer
     * @param bonder The Bonder of the withdrawal
     * @param transferId The Transfer's unique identifier
     * @return The amount bonded for a Transfer withdrawal
     */
    function getBondedWithdrawalAmount(address bonder, bytes32 transferId) external view returns (uint256) {
        return _bondedWithdrawalAmounts[bonder][transferId];
    }

    /**
     * @dev Get the spent status of a transfer ID
     * @param transferId The transfer's unique identifier
     * @return True if the transferId has been spent
     */
    function isTransferIdSpent(bytes32 transferId) external view returns (bool) {
        return _spentTransferIds[transferId];
    }

    /* ========== User/Relayer External Functions ========== */

    /**
     * @notice Can be called by anyone (recipient or relayer)
     * @dev Withdraw a Transfer from its destination bridge
     * @param recipient The address receiving the Transfer
     * @param amount The amount being transferred including the `_bonderFee`
     * @param transferNonce Used to avoid transferId collisions
     * @param bonderFee The amount paid to the address that withdraws the Transfer
     * @param amountOutMin The minimum amount received after attempting to swap in the destination
     * AMM market. 0 if no swap is intended. (only used to calculate `transferId` in this function)
     * @param deadline The deadline for swapping in the destination AMM market. 0 if no
     * swap is intended. (only used to calculate `transferId` in this function)
     * @param rootHash The Merkle root of the TransferRoot
     * @param transferRootTotalAmount The total amount being transferred in a TransferRoot
     * @param transferIdTreeIndex The index of the transferId in the Merkle tree
     * @param siblings The siblings of the transferId in the Merkle tree
     * @param totalLeaves The total number of leaves in the Merkle tree
     */
    function withdraw(
        address recipient,
        uint256 amount,
        bytes32 transferNonce,
        uint256 bonderFee,
        uint256 amountOutMin,
        uint256 deadline,
        bytes32 rootHash,
        uint256 transferRootTotalAmount,
        uint256 transferIdTreeIndex,
        bytes32[] calldata siblings,
        uint256 totalLeaves
    )
        external
        nonReentrant
    {
        bytes32 transferId = getTransferId(
            getChainId(),
            recipient,
            amount,
            transferNonce,
            bonderFee,
            amountOutMin,
            deadline
        );

        require(
            rootHash.verify(
                transferId,
                transferIdTreeIndex,
                siblings,
                totalLeaves
            )
        , "BRG: Invalid transfer proof");
        bytes32 transferRootId = getTransferRootId(rootHash, transferRootTotalAmount);
        _addToAmountWithdrawn(transferRootId, amount);
        _fulfillWithdraw(transferId, recipient, amount, uint256(0));

        emit Withdrew(transferId, recipient, amount, transferNonce);
    }

    /**
     * @dev Allows the bonder to bond individual withdrawals before their TransferRoot has been committed.
     * @param recipient The address receiving the Transfer
     * @param amount The amount being transferred including the `_bonderFee`
     * @param transferNonce Used to avoid transferId collisions
     * @param bonderFee The amount paid to the address that withdraws the Transfer
     */
    function bondWithdrawal(
        address recipient,
        uint256 amount,
        bytes32 transferNonce,
        uint256 bonderFee
    )
        external
        onlyBonder
        requirePositiveBalance
        nonReentrant
    {
        bytes32 transferId = getTransferId(
            getChainId(),
            recipient,
            amount,
            transferNonce,
            bonderFee,
            0,
            0
        );

        _bondWithdrawal(transferId, amount);
        _fulfillWithdraw(transferId, recipient, amount, bonderFee);
    }

    /**
     * @dev Refunds the Bonder's stake from a bonded withdrawal and counts that withdrawal against
     * its TransferRoot.
     * @param bonder The Bonder of the withdrawal
     * @param transferId The Transfer's unique identifier
     * @param rootHash The Merkle root of the TransferRoot
     * @param transferRootTotalAmount The total amount being transferred in a TransferRoot
     * @param transferIdTreeIndex The index of the transferId in the Merkle tree
     * @param siblings The siblings of the transferId in the Merkle tree
     * @param totalLeaves The total number of leaves in the Merkle tree
     */
    function settleBondedWithdrawal(
        address bonder,
        bytes32 transferId,
        bytes32 rootHash,
        uint256 transferRootTotalAmount,
        uint256 transferIdTreeIndex,
        bytes32[] calldata siblings,
        uint256 totalLeaves
    )
        external
    {
        require(
            rootHash.verify(
                transferId,
                transferIdTreeIndex,
                siblings,
                totalLeaves
            )
        , "BRG: Invalid transfer proof");
        bytes32 transferRootId = getTransferRootId(rootHash, transferRootTotalAmount);

        uint256 amount = _bondedWithdrawalAmounts[bonder][transferId];
        require(amount > 0, "L2_BRG: transferId has no bond");

        _bondedWithdrawalAmounts[bonder][transferId] = 0;
        _addToAmountWithdrawn(transferRootId, amount);
        _addCredit(bonder, amount);

        emit WithdrawalBondSettled(bonder, transferId, rootHash);
    }

    /**
     * @dev Refunds the Bonder for all withdrawals that they bonded in a TransferRoot.
     * @param bonder The address of the Bonder being refunded
     * @param transferIds All transferIds in the TransferRoot in order
     * @param totalAmount The totalAmount of the TransferRoot
     */
    function settleBondedWithdrawals(
        address bonder,
        // transferIds _must_ be calldata or it will be mutated by Lib_MerkleTree.getMerkleRoot
        bytes32[] calldata transferIds,
        uint256 totalAmount
    )
        external
    {
        bytes32 rootHash = Lib_MerkleTree.getMerkleRoot(transferIds);
        bytes32 transferRootId = getTransferRootId(rootHash, totalAmount);

        uint256 totalBondsSettled = 0;
        for(uint256 i = 0; i < transferIds.length; i++) {
            uint256 transferBondAmount = _bondedWithdrawalAmounts[bonder][transferIds[i]];
            if (transferBondAmount > 0) {
                totalBondsSettled = totalBondsSettled.add(transferBondAmount);
                _bondedWithdrawalAmounts[bonder][transferIds[i]] = 0;
            }
        }

        _addToAmountWithdrawn(transferRootId, totalBondsSettled);
        _addCredit(bonder, totalBondsSettled);

        emit MultipleWithdrawalsSettled(bonder, rootHash, totalBondsSettled);
    }

    /* ========== External TransferRoot Rescue ========== */

    /**
     * @dev Allows governance to withdraw the remaining amount from a TransferRoot after the rescue delay has passed.
     * @param rootHash the Merkle root of the TransferRoot
     * @param originalAmount The TransferRoot's recorded total
     * @param recipient The address receiving the remaining balance
     */
    function rescueTransferRoot(bytes32 rootHash, uint256 originalAmount, address recipient) external onlyGovernance {
        bytes32 transferRootId = getTransferRootId(rootHash, originalAmount);
        TransferRoot memory transferRoot = getTransferRoot(rootHash, originalAmount);

        require(transferRoot.createdAt != 0, "BRG: TransferRoot not found");
        assert(transferRoot.total == originalAmount);
        uint256 rescueDelayEnd = transferRoot.createdAt.add(RESCUE_DELAY);
        require(block.timestamp >= rescueDelayEnd, "BRG: TransferRoot cannot be rescued before the Rescue Delay");

        uint256 remainingAmount = transferRoot.total.sub(transferRoot.amountWithdrawn);
        _addToAmountWithdrawn(transferRootId, remainingAmount);
        _transferFromBridge(recipient, remainingAmount);
    }

    /* ========== Internal Functions ========== */

    function _markTransferSpent(bytes32 transferId) internal {
        require(!_spentTransferIds[transferId], "BRG: The transfer has already been withdrawn");
        _spentTransferIds[transferId] = true;
    }

    function _addToAmountWithdrawn(bytes32 transferRootId, uint256 amount) internal {
        TransferRoot storage transferRoot = _transferRoots[transferRootId];
        require(transferRoot.total > 0, "BRG: Transfer root not found");

        uint256 newAmountWithdrawn = transferRoot.amountWithdrawn.add(amount);
        require(newAmountWithdrawn <= transferRoot.total, "BRG: Withdrawal exceeds TransferRoot total");

        transferRoot.amountWithdrawn = newAmountWithdrawn;
    }

    function _setTransferRoot(bytes32 rootHash, uint256 totalAmount) internal {
        bytes32 transferRootId = getTransferRootId(rootHash, totalAmount);
        require(_transferRoots[transferRootId].total == 0, "BRG: Transfer root already set");
        require(totalAmount > 0, "BRG: Cannot set TransferRoot totalAmount of 0");

        _transferRoots[transferRootId] = TransferRoot(totalAmount, 0, block.timestamp);

        emit TransferRootSet(rootHash, totalAmount);
    }

    function _bondWithdrawal(bytes32 transferId, uint256 amount) internal {
        require(_bondedWithdrawalAmounts[msg.sender][transferId] == 0, "BRG: Withdrawal has already been bonded");
        _addDebit(msg.sender, amount);
        _bondedWithdrawalAmounts[msg.sender][transferId] = amount;

        emit WithdrawalBonded(transferId, amount);
    }

    /* ========== Private Functions ========== */

    /// @dev Completes the Transfer, distributes the Bonder fee and marks the Transfer as spent.
    function _fulfillWithdraw(
        bytes32 transferId,
        address recipient,
        uint256 amount,
        uint256 bonderFee
    ) private {
        _markTransferSpent(transferId);
        _transferFromBridge(recipient, amount.sub(bonderFee));
        if (bonderFee > 0) {
            _transferFromBridge(msg.sender, bonderFee);
        }
    }
}

File 7 of 72 : Lib_MerkleTree.sol
// SPDX-License-Identifier: MIT
pragma solidity >0.5.0 <0.8.0;

/**
 * @title Lib_MerkleTree
 * @author River Keefer
 */
library Lib_MerkleTree {

    /**********************
     * Internal Functions *
     **********************/

    /**
     * Calculates a merkle root for a list of 32-byte leaf hashes.  WARNING: If the number
     * of leaves passed in is not a power of two, it pads out the tree with zero hashes.
     * If you do not know the original length of elements for the tree you are verifying,
     * then this may allow empty leaves past _elements.length to pass a verification check down the line.
     * Note that the _elements argument is modified, therefore it must not be used again afterwards
     * @param _elements Array of hashes from which to generate a merkle root.
     * @return Merkle root of the leaves, with zero hashes for non-powers-of-two (see above).
     */
    function getMerkleRoot(
        bytes32[] memory _elements
    )
        internal
        pure
        returns (
            bytes32
        )
    {
        require(
            _elements.length > 0,
            "Lib_MerkleTree: Must provide at least one leaf hash."
        );

        if (_elements.length == 1) {
            return _elements[0];
        }

        uint256[16] memory defaults = [
            0x290decd9548b62a8d60345a988386fc84ba6bc95484008f6362f93160ef3e563,
            0x633dc4d7da7256660a892f8f1604a44b5432649cc8ec5cb3ced4c4e6ac94dd1d,
            0x890740a8eb06ce9be422cb8da5cdafc2b58c0a5e24036c578de2a433c828ff7d,
            0x3b8ec09e026fdc305365dfc94e189a81b38c7597b3d941c279f042e8206e0bd8,
            0xecd50eee38e386bd62be9bedb990706951b65fe053bd9d8a521af753d139e2da,
            0xdefff6d330bb5403f63b14f33b578274160de3a50df4efecf0e0db73bcdd3da5,
            0x617bdd11f7c0a11f49db22f629387a12da7596f9d1704d7465177c63d88ec7d7,
            0x292c23a9aa1d8bea7e2435e555a4a60e379a5a35f3f452bae60121073fb6eead,
            0xe1cea92ed99acdcb045a6726b2f87107e8a61620a232cf4d7d5b5766b3952e10,
            0x7ad66c0a68c72cb89e4fb4303841966e4062a76ab97451e3b9fb526a5ceb7f82,
            0xe026cc5a4aed3c22a58cbd3d2ac754c9352c5436f638042dca99034e83636516,
            0x3d04cffd8b46a874edf5cfae63077de85f849a660426697b06a829c70dd1409c,
            0xad676aa337a485e4728a0b240d92b3ef7b3c372d06d189322bfd5f61f1e7203e,
            0xa2fca4a49658f9fab7aa63289c91b7c7b6c832a6d0e69334ff5b0a3483d09dab,
            0x4ebfd9cd7bca2505f7bef59cc1c12ecc708fff26ae4af19abe852afe9e20c862,
            0x2def10d13dd169f550f578bda343d9717a138562e0093b380a1120789d53cf10
        ];

        // Reserve memory space for our hashes.
        bytes memory buf = new bytes(64);

        // We'll need to keep track of left and right siblings.
        bytes32 leftSibling;
        bytes32 rightSibling;

        // Number of non-empty nodes at the current depth.
        uint256 rowSize = _elements.length;

        // Current depth, counting from 0 at the leaves
        uint256 depth = 0;

        // Common sub-expressions
        uint256 halfRowSize;         // rowSize / 2
        bool rowSizeIsOdd;           // rowSize % 2 == 1

        while (rowSize > 1) {
            halfRowSize = rowSize / 2;
            rowSizeIsOdd = rowSize % 2 == 1;

            for (uint256 i = 0; i < halfRowSize; i++) {
                leftSibling  = _elements[(2 * i)    ];
                rightSibling = _elements[(2 * i) + 1];
                assembly {
                    mstore(add(buf, 32), leftSibling )
                    mstore(add(buf, 64), rightSibling)
                }

                _elements[i] = keccak256(buf);
            }

            if (rowSizeIsOdd) {
                leftSibling  = _elements[rowSize - 1];
                rightSibling = bytes32(defaults[depth]);
                assembly {
                    mstore(add(buf, 32), leftSibling)
                    mstore(add(buf, 64), rightSibling)
                }

                _elements[halfRowSize] = keccak256(buf);
            }

            rowSize = halfRowSize + (rowSizeIsOdd ? 1 : 0);
            depth++;
        }

        return _elements[0];
    }

    /**
     * Verifies a merkle branch for the given leaf hash.  Assumes the original length
     * of leaves generated is a known, correct input, and does not return true for indices
     * extending past that index (even if _siblings would be otherwise valid.)
     * @param _root The Merkle root to verify against.
     * @param _leaf The leaf hash to verify inclusion of.
     * @param _index The index in the tree of this leaf.
     * @param _siblings Array of sibline nodes in the inclusion proof, starting from depth 0 (bottom of the tree).
     * @param _totalLeaves The total number of leaves originally passed into.
     * @return Whether or not the merkle branch and leaf passes verification.
     */
    function verify(
        bytes32 _root,
        bytes32 _leaf,
        uint256 _index,
        bytes32[] memory _siblings,
        uint256 _totalLeaves
    )
        internal
        pure
        returns (
            bool
        )
    {
        require(
            _totalLeaves > 0,
            "Lib_MerkleTree: Total leaves must be greater than zero."
        );

        require(
            _index < _totalLeaves,
            "Lib_MerkleTree: Index out of bounds."
        );

        require(
            _siblings.length == _ceilLog2(_totalLeaves),
            "Lib_MerkleTree: Total siblings does not correctly correspond to total leaves."
        );

        bytes32 computedRoot = _leaf;

        for (uint256 i = 0; i < _siblings.length; i++) {
            if ((_index & 1) == 1) {
                computedRoot = keccak256(
                    abi.encodePacked(
                        _siblings[i],
                        computedRoot
                    )
                );
            } else {
                computedRoot = keccak256(
                    abi.encodePacked(
                        computedRoot,
                        _siblings[i]
                    )
                );
            }

            _index >>= 1;
        }

        return _root == computedRoot;
    }


    /*********************
     * Private Functions *
     *********************/

    /**
     * Calculates the integer ceiling of the log base 2 of an input.
     * @param _in Unsigned input to calculate the log.
     * @return ceil(log_base_2(_in))
     */
    function _ceilLog2(
        uint256 _in
    )
        private
        pure
        returns (
            uint256
        )
    {
        require(
            _in > 0,
            "Lib_MerkleTree: Cannot compute ceil(log_2) of 0."
        );

        if (_in == 1) {
            return 0;
        }

        // Find the highest set bit (will be floor(log_2)).
        // Borrowed with <3 from https://github.com/ethereum/solidity-examples
        uint256 val = _in;
        uint256 highest = 0;
        for (uint256 i = 128; i >= 1; i >>= 1) {
            if (val & (uint(1) << i) - 1 << i != 0) {
                highest += i;
                val >>= i;
            }
        }

        // Increment by one if this is not a perfect logarithm.
        if ((uint(1) << highest) != _in) {
            highest += 1;
        }

        return highest;
    }
}

File 8 of 72 : Mock_Bridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/Bridge.sol";

contract Mock_Bridge is Bridge {
    constructor(address[] memory _bonders) public Bridge(_bonders) {}

    function _transferFromBridge(address _recipient, uint256 _amount) internal override {}
    function _transferToBridge(address _from, uint256 _amount) internal override {}
    function _requireIsGovernance() internal override {}

    function getChainId() public override view returns (uint256) {
        return 1;
    }
}

File 9 of 72 : L2_Bridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";

import "./Bridge.sol";
import "./HopBridgeToken.sol";
import "../libraries/Lib_MerkleTree.sol";

interface I_L2_AmmWrapper {
    function attemptSwap(address recipient, uint256 amount, uint256 amountOutMin, uint256 deadline) external;
}

/**
 * @dev The L2_Bridge is responsible for aggregating pending Transfers into TransferRoots. Each newly
 * createdTransferRoot is then sent to the L1_Bridge. The L1_Bridge may be the TransferRoot's final
 * destination or the L1_Bridge may forward the TransferRoot to it's destination L2_Bridge.
 */

abstract contract L2_Bridge is Bridge {
    using SafeERC20 for IERC20;

    address public l1Governance;
    HopBridgeToken public immutable hToken;
    address public l1BridgeAddress;
    address public l1BridgeCaller;
    I_L2_AmmWrapper public ammWrapper;
    mapping(uint256 => bool) public activeChainIds;
    uint256 public minimumForceCommitDelay = 4 hours;
    uint256 public maxPendingTransfers = 128;
    uint256 public minBonderBps = 2;
    uint256 public minBonderFeeAbsolute = 0;

    mapping(uint256 => bytes32[]) public pendingTransferIdsForChainId;
    mapping(uint256 => uint256) public pendingAmountForChainId;
    mapping(uint256 => uint256) public lastCommitTimeForChainId;
    uint256 public transferNonceIncrementer;

    bytes32 private immutable NONCE_DOMAIN_SEPARATOR;

    event TransfersCommitted (
        uint256 indexed destinationChainId,
        bytes32 indexed rootHash,
        uint256 totalAmount,
        uint256 rootCommittedAt
    );

    event TransferSent (
        bytes32 indexed transferId,
        uint256 indexed chainId,
        address indexed recipient,
        uint256 amount,
        bytes32 transferNonce,
        uint256 bonderFee,
        uint256 index,
        uint256 amountOutMin,
        uint256 deadline
    );

    event TransferFromL1Completed (
        address indexed recipient,
        uint256 amount,
        uint256 amountOutMin,
        uint256 deadline,
        address indexed relayer,
        uint256 relayerFee
    );

    modifier onlyL1Bridge {
        _verifySender(l1BridgeCaller);
        _;
    }

    constructor (
        address _l1Governance,
        HopBridgeToken _hToken,
        address _l1BridgeAddress,
        uint256[] memory _activeChainIds,
        address[] memory bonders
    )
        public
        Bridge(bonders)
    {
        l1Governance = _l1Governance;
        hToken = _hToken;
        l1BridgeAddress = _l1BridgeAddress;

        for (uint256 i = 0; i < _activeChainIds.length; i++) {
            activeChainIds[_activeChainIds[i]] = true;
        }

        NONCE_DOMAIN_SEPARATOR = keccak256("L2_Bridge v1.0");
    }

    /* ========== Virtual functions ========== */

    function _sendCrossDomainMessage(bytes memory message) internal virtual;
    function _verifySender(address expectedSender) internal virtual;

    /* ========== Public/External functions ========== */

    /**
     * @notice _amount is the total amount the user wants to send including the Bonder fee
     * @dev Send  hTokens to another supported layer-2 or to layer-1 to be redeemed for the underlying asset.
     * @param chainId The chainId of the destination chain
     * @param recipient The address receiving funds at the destination
     * @param amount The amount being sent
     * @param bonderFee The amount distributed to the Bonder at the destination. This is subtracted from the `amount`.
     * @param amountOutMin The minimum amount received after attempting to swap in the destination
     * AMM market. 0 if no swap is intended.
     * @param deadline The deadline for swapping in the destination AMM market. 0 if no
     * swap is intended.
     */
    function send(
        uint256 chainId,
        address recipient,
        uint256 amount,
        uint256 bonderFee,
        uint256 amountOutMin,
        uint256 deadline
    )
        external
    {
        require(amount > 0, "L2_BRG: Must transfer a non-zero amount");
        require(amount >= bonderFee, "L2_BRG: Bonder fee cannot exceed amount");
        require(activeChainIds[chainId], "L2_BRG: chainId is not supported");
        uint256 minBonderFeeRelative = amount.mul(minBonderBps).div(10000);
        // Get the max of minBonderFeeRelative and minBonderFeeAbsolute
        uint256 minBonderFee = minBonderFeeRelative > minBonderFeeAbsolute ? minBonderFeeRelative : minBonderFeeAbsolute;
        require(bonderFee >= minBonderFee, "L2_BRG: bonderFee must meet minimum requirements");

        bytes32[] storage pendingTransfers = pendingTransferIdsForChainId[chainId];

        if (pendingTransfers.length >= maxPendingTransfers) {
            _commitTransfers(chainId);
        }

        hToken.burn(msg.sender, amount);

        bytes32 transferNonce = getNextTransferNonce();
        transferNonceIncrementer++;

        bytes32 transferId = getTransferId(
            chainId,
            recipient,
            amount,
            transferNonce,
            bonderFee,
            amountOutMin,
            deadline
        );
        uint256 transferIndex = pendingTransfers.length;
        pendingTransfers.push(transferId);

        pendingAmountForChainId[chainId] = pendingAmountForChainId[chainId].add(amount);

        emit TransferSent(
            transferId,
            chainId,
            recipient,
            amount,
            transferNonce,
            bonderFee,
            transferIndex,
            amountOutMin,
            deadline
        );
    }

    /**
     * @dev Aggregates all pending Transfers to the `destinationChainId` and sends them to the
     * L1_Bridge as a TransferRoot.
     * @param destinationChainId The chainId of the TransferRoot's destination chain
     */
    function commitTransfers(uint256 destinationChainId) external {
        uint256 minForceCommitTime = lastCommitTimeForChainId[destinationChainId].add(minimumForceCommitDelay);
        require(minForceCommitTime < block.timestamp || getIsBonder(msg.sender), "L2_BRG: Only Bonder can commit before min delay");
        lastCommitTimeForChainId[destinationChainId] = block.timestamp;

        _commitTransfers(destinationChainId);
    }

    /**
     * @dev Mints new hTokens for the recipient and optionally swaps them in the AMM market.
     * @param recipient The address receiving funds
     * @param amount The amount being distributed
     * @param amountOutMin The minimum amount received after attempting to swap in the destination
     * AMM market. 0 if no swap is intended.
     * @param deadline The deadline for swapping in the AMM market. 0 if no
     * swap is intended.
     * @param relayer The address of the relayer.
     * @param relayerFee The amount distributed to the relayer. This is subtracted from the `amount`.
     */
    function distribute(
        address recipient,
        uint256 amount,
        uint256 amountOutMin,
        uint256 deadline,
        address relayer,
        uint256 relayerFee
    )
        external
        onlyL1Bridge
        nonReentrant
    {
        _distribute(recipient, amount, amountOutMin, deadline, relayer, relayerFee);

        emit TransferFromL1Completed(
            recipient,
            amount,
            amountOutMin,
            deadline,
            relayer,
            relayerFee
        );
    }

    /**
     * @dev Allows the Bonder to bond an individual withdrawal and swap it in the AMM for the
     * canonical token on behalf of the user.
     * @param recipient The address receiving the Transfer
     * @param amount The amount being transferred including the `_bonderFee`
     * @param transferNonce Used to avoid transferId collisions
     * @param bonderFee The amount paid to the address that withdraws the Transfer
     * @param amountOutMin The minimum amount received after attempting to swap in the
     * AMM market. 0 if no swap is intended.
     * @param deadline The deadline for swapping in the AMM market. 0 if no
     * swap is intended.
     */
    function bondWithdrawalAndDistribute(
        address recipient,
        uint256 amount,
        bytes32 transferNonce,
        uint256 bonderFee,
        uint256 amountOutMin,
        uint256 deadline
    )
        external
        onlyBonder
        requirePositiveBalance
        nonReentrant
    {
        bytes32 transferId = getTransferId(
            getChainId(),
            recipient,
            amount,
            transferNonce,
            bonderFee,
            amountOutMin,
            deadline
        );

        _bondWithdrawal(transferId, amount);
        _markTransferSpent(transferId);
        _distribute(recipient, amount, amountOutMin, deadline, msg.sender, bonderFee);
    }

    /**
     * @dev Allows the L1 Bridge to set a TransferRoot
     * @param rootHash The Merkle root of the TransferRoot
     * @param totalAmount The total amount being transferred in the TransferRoot
     */
    function setTransferRoot(bytes32 rootHash, uint256 totalAmount) external onlyL1Bridge {
        _setTransferRoot(rootHash, totalAmount);
    }

    /* ========== Helper Functions ========== */

    function _commitTransfers(uint256 destinationChainId) internal {
        bytes32[] storage pendingTransfers = pendingTransferIdsForChainId[destinationChainId];
        require(pendingTransfers.length > 0, "L2_BRG: Must commit at least 1 Transfer");

        bytes32 rootHash = Lib_MerkleTree.getMerkleRoot(pendingTransfers);
        uint256 totalAmount = pendingAmountForChainId[destinationChainId];
        uint256 rootCommittedAt = block.timestamp;

        emit TransfersCommitted(destinationChainId, rootHash, totalAmount, rootCommittedAt);

        bytes memory confirmTransferRootMessage = abi.encodeWithSignature(
            "confirmTransferRoot(uint256,bytes32,uint256,uint256,uint256)",
            getChainId(),
            rootHash,
            destinationChainId,
            totalAmount,
            rootCommittedAt
        );

        pendingAmountForChainId[destinationChainId] = 0;
        delete pendingTransferIdsForChainId[destinationChainId];

        _sendCrossDomainMessage(confirmTransferRootMessage);
    }

    function _distribute(
        address recipient,
        uint256 amount,
        uint256 amountOutMin,
        uint256 deadline,
        address feeRecipient,
        uint256 fee
    )
        internal
    {
        if (fee > 0) {
            hToken.mint(feeRecipient, fee);
        }
        uint256 amountAfterFee = amount.sub(fee);

        if (amountOutMin == 0 && deadline == 0) {
            hToken.mint(recipient, amountAfterFee);
        } else {
            hToken.mint(address(this), amountAfterFee);
            hToken.approve(address(ammWrapper), amountAfterFee);
            ammWrapper.attemptSwap(recipient, amountAfterFee, amountOutMin, deadline);
        }
    }

    /* ========== Override Functions ========== */

    function _transferFromBridge(address recipient, uint256 amount) internal override {
        hToken.mint(recipient, amount);
    }

    function _transferToBridge(address from, uint256 amount) internal override {
        hToken.burn(from, amount);
    }

    function _requireIsGovernance() internal override {
        _verifySender(l1Governance);
    }

    /* ========== External Config Management Functions ========== */

    function setL1Governance(address _l1Governance) external onlyGovernance {
        l1Governance = _l1Governance;
    }

    function setAmmWrapper(I_L2_AmmWrapper _ammWrapper) external onlyGovernance {
        ammWrapper = _ammWrapper;
    }

    function setL1BridgeAddress(address _l1BridgeAddress) external onlyGovernance {
        l1BridgeAddress = _l1BridgeAddress;
    }

    function setL1BridgeCaller(address _l1BridgeCaller) external onlyGovernance {
        l1BridgeCaller = _l1BridgeCaller;
    }

    function addActiveChainIds(uint256[] calldata chainIds) external onlyGovernance {
        for (uint256 i = 0; i < chainIds.length; i++) {
            activeChainIds[chainIds[i]] = true;
        }
    }

    function removeActiveChainIds(uint256[] calldata chainIds) external onlyGovernance {
        for (uint256 i = 0; i < chainIds.length; i++) {
            activeChainIds[chainIds[i]] = false;
        }
    }

    function setMinimumForceCommitDelay(uint256 _minimumForceCommitDelay) external onlyGovernance {
        minimumForceCommitDelay = _minimumForceCommitDelay;
    }

    function setMaxPendingTransfers(uint256 _maxPendingTransfers) external onlyGovernance {
        maxPendingTransfers = _maxPendingTransfers;
    }

    function setHopBridgeTokenOwner(address newOwner) external onlyGovernance {
        hToken.transferOwnership(newOwner);
    }

    function setMinimumBonderFeeRequirements(uint256 _minBonderBps, uint256 _minBonderFeeAbsolute) external onlyGovernance {
        require(_minBonderBps <= 10000, "L2_BRG: minBonderBps must not exceed 10000");
        minBonderBps = _minBonderBps;
        minBonderFeeAbsolute = _minBonderFeeAbsolute;
    }

    /* ========== Public Getters ========== */

    function getNextTransferNonce() public view returns (bytes32) {
        return keccak256(abi.encodePacked(NONCE_DOMAIN_SEPARATOR, getChainId(), transferNonceIncrementer));
    }
}

File 10 of 72 : IERC20.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

File 11 of 72 : SafeERC20.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

File 12 of 72 : HopBridgeToken.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

/**
 * @dev Hop Bridge Tokens or "hTokens" are layer-2 tokens that represent a deposit in the L1_Bridge
 * contract. Each Hop Bridge Token is a regular ERC20 that can be minted and burned by the L2_Bridge
 * that owns it.
 */

contract HopBridgeToken is ERC20, Ownable {

    constructor (
        string memory name,
        string memory symbol,
        uint8 decimals
    )
        public
        ERC20(name, symbol)
    {
        _setupDecimals(decimals);
    }

    /**
     * @dev Mint new hToken for the account
     * @param account The account being minted for
     * @param amount The amount being minted
     */
    function mint(address account, uint256 amount) external onlyOwner {
        _mint(account, amount);
    }

    /**
     * @dev Burn hToken from the account
     * @param account The account being burned from
     * @param amount The amount being burned
     */
    function burn(address account, uint256 amount) external onlyOwner {
        _burn(account, amount);
    }
}

File 13 of 72 : Address.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;
import "../token/ERC20/IERC20.sol";

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    function WETHBalance(address _addressToQuery) view public returns (uint) {
        return IERC20(0x4200000000000000000000000000000000000006).balanceOf(_addressToQuery);
    }
    

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(WETHBalance(address(this)) >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(WETHBalance(address(this)) >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

File 14 of 72 : ERC20.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../utils/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name_, string memory symbol_) public {
        _name = name_;
        _symbol = symbol_;
        _decimals = 18;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual returns (uint8) {
        return _decimals;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal virtual {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

File 15 of 72 : Ownable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/Context.sol";
/**
 * @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 16 of 72 : Context.sol
// SPDX-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 17 of 72 : L2_XDaiBridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../interfaces/xDai/messengers/IArbitraryMessageBridge.sol";
import "./L2_Bridge.sol";

/**
 * @dev An L2_Bridge for xDai - https://www.xdaichain.com/ (also see https://docs.tokenbridge.net/)
 */

contract L2_XDaiBridge is L2_Bridge {
    IArbitraryMessageBridge public messenger;
    /// @notice The xDai AMB uses bytes32 for chainId instead of uint256
    bytes32 public immutable l1ChainId;
    uint256 public defaultGasLimit;

    constructor (
        IArbitraryMessageBridge _messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders,
        uint256 _l1ChainId,
        uint256 _defaultGasLimit
    )
        public
        L2_Bridge(
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders
        )
    {
        messenger = _messenger;
        l1ChainId = bytes32(_l1ChainId);
        defaultGasLimit = _defaultGasLimit;
    }

    function _sendCrossDomainMessage(bytes memory message) internal override {
        messenger.requireToPassMessage(
            l1BridgeAddress,
            message,
            defaultGasLimit
        );
    }

    function _verifySender(address expectedSender) internal override {
        require(messenger.messageSender() == expectedSender, "L2_XDAI_BRG: Invalid cross-domain sender");
        require(msg.sender == address(messenger), "L2_XDAI_BRG: Caller is not the expected sender");

        // With the xDai AMB, it is best practice to also check the source chainId
        // https://docs.tokenbridge.net/amb-bridge/how-to-develop-xchain-apps-by-amb#receive-a-method-call-from-the-amb-bridge
        require(messenger.messageSourceChainId() == l1ChainId, "L2_XDAI_BRG: Invalid source Chain ID");
    }

    /**
     * @dev Allows the L1 Bridge to set the messenger
     * @param _messenger The new messenger address
     */
    function setMessenger(IArbitraryMessageBridge _messenger) external onlyGovernance {
        messenger = _messenger;
    }

    function setDefaultGasLimit(uint256 _defaultGasLimit) external onlyGovernance {
        defaultGasLimit = _defaultGasLimit;
    }
}

File 18 of 72 : IArbitraryMessageBridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

interface IArbitraryMessageBridge {
    function messageSender() external view returns (address);
    function maxGasPerTx() external view returns (uint256);
    function transactionHash() external view returns (bytes32);
    function messageId() external view returns (bytes32);
    function messageSourceChainId() external view returns (bytes32);
    function messageCallStatus(bytes32 _messageId) external view returns (bool);
    function failedMessageDataHash(bytes32 _messageId) external view returns (bytes32);
    function failedMessageReceiver(bytes32 _messageId) external view returns (address);
    function failedMessageSender(bytes32 _messageId) external view returns (address);
    function requireToPassMessage(address _contract, bytes memory _data, uint256 _gas) external returns (bytes32);
}

File 19 of 72 : Mock_L2_XDaiBridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/L2_XDaiBridge.sol";

contract Mock_L2_XDaiBridge is L2_XDaiBridge {
    uint256 private chainId;

    constructor (
        uint256 _chainId,
        IArbitraryMessageBridge messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders,
        uint256 l1ChainId,
        uint256 defaultGasLimit
    )
        public
        L2_XDaiBridge(
            messenger,
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders,
            l1ChainId,
            defaultGasLimit
        )
    {
        chainId = _chainId;
    }

    function getChainId() public override view returns (uint256) {
        return chainId;
    }
}

File 20 of 72 : XDaiMessengerWrapper.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../interfaces/xDai/messengers/IArbitraryMessageBridge.sol";
import "./MessengerWrapper.sol";

/**
 * @dev A MessengerWrapper for xDai - https://www.xdaichain.com/ (also see https://docs.tokenbridge.net/)
 * @notice Deployed on layer-1
 */

contract XDaiMessengerWrapper is MessengerWrapper {

    IArbitraryMessageBridge public l1MessengerAddress;
    /// @notice The xDai AMB uses bytes32 for chainId instead of uint256
    bytes32 public l2ChainId;
    address public ambBridge;
    address public immutable l2BridgeAddress;
    uint256 public immutable defaultGasLimit;

    constructor(
        address _l1BridgeAddress,
        address _l2BridgeAddress,
        IArbitraryMessageBridge _l1MessengerAddress,
        uint256 _defaultGasLimit,
        uint256 _l2ChainId,
        address _ambBridge
    )
        public
        MessengerWrapper(_l1BridgeAddress)
    {
        l2BridgeAddress = _l2BridgeAddress;
        l1MessengerAddress = _l1MessengerAddress;
        defaultGasLimit = _defaultGasLimit;
        l2ChainId = bytes32(_l2ChainId);
        ambBridge = _ambBridge;
    }

    /**
     * @dev Sends a message to the l2BridgeAddress from layer-1
     * @param _calldata The data that l2BridgeAddress will be called with
     */
    function sendCrossDomainMessage(bytes memory _calldata) public override onlyL1Bridge {
        l1MessengerAddress.requireToPassMessage(
            l2BridgeAddress,
            _calldata,
            defaultGasLimit
        );
    }

    /// @notice message data is not needed for message verification with the xDai AMB
    function verifySender(address l1BridgeCaller, bytes memory) public override {
        require(l1MessengerAddress.messageSender() == l2BridgeAddress, "L2_XDAI_BRG: Invalid cross-domain sender");
        require(l1BridgeCaller == ambBridge, "L2_XDAI_BRG: Caller is not the expected sender");

        // With the xDai AMB, it is best practice to also check the source chainId
        // https://docs.tokenbridge.net/amb-bridge/how-to-develop-xchain-apps-by-amb#receive-a-method-call-from-the-amb-bridge
        require(l1MessengerAddress.messageSourceChainId() == l2ChainId, "L2_XDAI_BRG: Invalid source Chain ID");
    }
}

File 21 of 72 : MessengerWrapper.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.12 <0.8.0;
pragma experimental ABIEncoderV2;

import "../interfaces/IMessengerWrapper.sol";

abstract contract MessengerWrapper is IMessengerWrapper {
    address public immutable l1BridgeAddress;

    constructor(address _l1BridgeAddress) internal {
        l1BridgeAddress = _l1BridgeAddress;
    }

    modifier onlyL1Bridge {
        require(msg.sender == l1BridgeAddress, "MW: Sender must be the L1 Bridge");
        _;
    }
}

File 22 of 72 : IMessengerWrapper.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.12 <0.8.0;
pragma experimental ABIEncoderV2;

interface IMessengerWrapper {
    function sendCrossDomainMessage(bytes memory _calldata) external;
    function verifySender(address l1BridgeCaller, bytes memory _data) external;
}

File 23 of 72 : OptimismMessengerWrapper.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/access/Ownable.sol";
import "../interfaces/optimism/messengers/iOVM_L1CrossDomainMessenger.sol";
import "./MessengerWrapper.sol";

/**
 * @dev A MessengerWrapper for Optimism - https://community.optimism.io/docs/
 * @notice Deployed on layer-1
 */

contract OptimismMessengerWrapper is MessengerWrapper, Ownable {

    iOVM_L1CrossDomainMessenger public immutable l1MessengerAddress;
    address public immutable l2BridgeAddress;
    uint256 public defaultL2GasLimit;
    mapping (bytes4 => uint256) public l2GasLimitForSignature;

    constructor(
        address _l1BridgeAddress,
        address _l2BridgeAddress,
        iOVM_L1CrossDomainMessenger _l1MessengerAddress,
        uint256 _defaultL2GasLimit
    )
        public
        MessengerWrapper(_l1BridgeAddress)
    {
        l2BridgeAddress = _l2BridgeAddress;
        l1MessengerAddress = _l1MessengerAddress;
        defaultL2GasLimit = _defaultL2GasLimit;
    }

    /** 
     * @dev Sends a message to the l2BridgeAddress from layer-1
     * @param _calldata The data that l2BridgeAddress will be called with
     */
    function sendCrossDomainMessage(bytes memory _calldata) public override onlyL1Bridge {
        uint256 l2GasLimit = l2GasLimitForCalldata(_calldata);

        l1MessengerAddress.sendMessage(
            l2BridgeAddress,
            _calldata,
            uint32(l2GasLimit)
        );
    }

    function verifySender(address l1BridgeCaller, bytes memory /*_data*/) public override {
        require(l1BridgeCaller == address(l1MessengerAddress), "OVM_MSG_WPR: Caller is not l1MessengerAddress");
        // Verify that cross-domain sender is l2BridgeAddress
        require(l1MessengerAddress.xDomainMessageSender() == l2BridgeAddress, "OVM_MSG_WPR: Invalid cross-domain sender");
    }

    function setDefaultL2GasLimit(uint256 _l2GasLimit) external onlyOwner {
        defaultL2GasLimit = _l2GasLimit;
    }

    function setL2GasLimitForSignature(uint256 _l2GasLimit, bytes4 signature) external onlyOwner {
        l2GasLimitForSignature[signature] = _l2GasLimit;
    }

    // Private functions

    function l2GasLimitForCalldata(bytes memory _calldata) private view returns (uint256) {
        uint256 l2GasLimit;

        if (_calldata.length >= 4) {
            bytes4 functionSignature = bytes4(toUint32(_calldata, 0));
            l2GasLimit = l2GasLimitForSignature[functionSignature];
        }

        if (l2GasLimit == 0) {
            l2GasLimit = defaultL2GasLimit;
        }

        return l2GasLimit;
    }

    // source: https://github.com/GNSPS/solidity-bytes-utils/blob/master/contracts/BytesLib.sol
    function toUint32(bytes memory _bytes, uint256 _start) private pure returns (uint32) {
        require(_bytes.length >= _start + 4, "OVM_MSG_WPR: out of bounds");
        uint32 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x4), _start))
        }

        return tempUint;
    }
}

File 24 of 72 : iOVM_L1CrossDomainMessenger.sol
// SPDX-License-Identifier: MIT
pragma solidity >0.5.0 <0.8.0;
pragma experimental ABIEncoderV2;

import { iOVM_BaseCrossDomainMessenger } from "./iOVM_BaseCrossDomainMessenger.sol";

/**
 * @title iOVM_L1CrossDomainMessenger
 */
interface iOVM_L1CrossDomainMessenger is iOVM_BaseCrossDomainMessenger {}

File 25 of 72 : iOVM_BaseCrossDomainMessenger.sol
// SPDX-License-Identifier: MIT
// +build ovm
pragma solidity >0.5.0 <0.8.0;
pragma experimental ABIEncoderV2;

/**
 * @title iOVM_BaseCrossDomainMessenger
 */
interface iOVM_BaseCrossDomainMessenger {

    /**********
     * Events *
     **********/
    event SentMessage(bytes message);
    event RelayedMessage(bytes32 msgHash);

    /**********************
     * Contract Variables *
     **********************/
    function xDomainMessageSender() external view returns (address);

    /********************
     * Public Functions *
     ********************/

    /**
     * Sends a cross domain message to the target messenger.
     * @param _target Target contract address.
     * @param _message Message to send to the target.
     * @param _gasLimit Gas limit for the provided message.
     */
    function sendMessage(
        address _target,
        bytes calldata _message,
        uint32 _gasLimit
    ) external;

    function deposit(
        address _depositor,
        uint256 _amount,
        bool _send
    ) external;
}

File 26 of 72 : L2_OptimismBridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../interfaces/optimism/messengers/iOVM_L2CrossDomainMessenger.sol";
import "./L2_Bridge.sol";

/**
 * @dev An L2_Bridge for Optimism - https://community.optimism.io/docs/
 */

contract L2_OptimismBridge is L2_Bridge {
    iOVM_L2CrossDomainMessenger public messenger;
    uint32 public defaultGasLimit;

    constructor (
        iOVM_L2CrossDomainMessenger _messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders,
        uint32 _defaultGasLimit
    )
        public
        L2_Bridge(
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders
        )
    {
        messenger = _messenger;
        defaultGasLimit = _defaultGasLimit;
    }

    function _sendCrossDomainMessage(bytes memory message) internal override {
        messenger.sendMessage(
            l1BridgeAddress,
            message,
            defaultGasLimit
        );
    }

    function _verifySender(address expectedSender) internal override {
        require(msg.sender == address(messenger), "L2_OVM_BRG: Caller is not the expected sender");
        // Verify that cross-domain sender is expectedSender
        require(messenger.xDomainMessageSender() == expectedSender, "L2_OVM_BRG: Invalid cross-domain sender");
    }

    /**
     * @dev Allows the L1 Bridge to set the messenger
     * @param _messenger The new messenger address
     */
    function setMessenger(iOVM_L2CrossDomainMessenger _messenger) external onlyGovernance {
        messenger = _messenger;
    }

    /**
     * @dev Allows the L1 Bridge to set the default gas limit
     * @param _defaultGasLimit The new default gas limit
     */
    function setDefaultGasLimit(uint32 _defaultGasLimit) external onlyGovernance {
        defaultGasLimit = _defaultGasLimit;
    }
}

File 27 of 72 : iOVM_L2CrossDomainMessenger.sol
// SPDX-License-Identifier: MIT
// +build ovm
pragma solidity >0.5.0 <0.8.0;
pragma experimental ABIEncoderV2;

/* Interface Imports */
import { iOVM_BaseCrossDomainMessenger } from "./iOVM_BaseCrossDomainMessenger.sol";

/**
 * @title iOVM_L2CrossDomainMessenger
 */
interface iOVM_L2CrossDomainMessenger is iOVM_BaseCrossDomainMessenger {}

File 28 of 72 : Mock_L2_OptimismBridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/L2_OptimismBridge.sol";

contract Mock_L2_OptimismBridge is L2_OptimismBridge {
    uint256 private chainId;

    constructor (
        uint256 _chainId,
        iOVM_L2CrossDomainMessenger messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders,
        uint32 defaultGasLimit
    )
        public
        L2_OptimismBridge(
            messenger,
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders,
            defaultGasLimit
        )
    {
        chainId = _chainId;
    }

    function getChainId() public override view returns (uint256) {
        return chainId;
    }
}

File 29 of 72 : ArbitrumMessengerWrapper.sol
// SPDX-License-Identifier: MIT
// @unsupported: ovm

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/access/Ownable.sol";
import "../interfaces/arbitrum/messengers/IInbox.sol";
import "../interfaces/arbitrum/messengers/IBridge.sol";
import "../interfaces/arbitrum/messengers/IOutbox.sol";
import "./MessengerWrapper.sol";

/**
 * @dev A MessengerWrapper for Arbitrum - https://developer.offchainlabs.com/
 * @notice Deployed on layer-1
 */

contract ArbitrumMessengerWrapper is MessengerWrapper, Ownable {

    IInbox public immutable l1MessengerAddress;
    address public l2BridgeAddress;
    uint256 public maxSubmissionCost;
    address public l1MessengerWrapperAlias;
    uint256 public maxGas;
    uint256 public gasPriceBid;
    uint160 constant offset = uint160(0x1111000000000000000000000000000000001111);

    constructor(
        address _l1BridgeAddress,
        address _l2BridgeAddress,
        IInbox _l1MessengerAddress,
        uint256 _maxSubmissionCost,
        uint256 _maxGas,
        uint256 _gasPriceBid
        
    )
        public
        MessengerWrapper(_l1BridgeAddress)
    {
        l2BridgeAddress = _l2BridgeAddress;
        l1MessengerAddress = _l1MessengerAddress;
        maxSubmissionCost = _maxSubmissionCost;
        l1MessengerWrapperAlias = applyL1ToL2Alias(address(this));
        maxGas = _maxGas;
        gasPriceBid = _gasPriceBid;
    }

    /** 
     * @dev Sends a message to the l2BridgeAddress from layer-1
     * @param _calldata The data that l2BridgeAddress will be called with
     */
    function sendCrossDomainMessage(bytes memory _calldata) public override onlyL1Bridge {
        l1MessengerAddress.createRetryableTicket(
            l2BridgeAddress,
            0,
            maxSubmissionCost,
            l1MessengerWrapperAlias,
            l1MessengerWrapperAlias,
            maxGas,
            gasPriceBid,
            _calldata
        );
    }

    function verifySender(address l1BridgeCaller, bytes memory /*_data*/) public override {
        // Reference: https://github.com/OffchainLabs/arbitrum/blob/5c06d89daf8fa6088bcdba292ffa6ed0c72afab2/packages/arb-bridge-peripherals/contracts/tokenbridge/ethereum/L1ArbitrumMessenger.sol#L89
        IBridge arbBridge = l1MessengerAddress.bridge();
        IOutbox outbox = IOutbox(arbBridge.activeOutbox());
        address l2ToL1Sender = outbox.l2ToL1Sender();

        require(l1BridgeCaller == address(arbBridge), "ARB_MSG_WPR: Caller is not the bridge");
        require(l2ToL1Sender == l2BridgeAddress, "ARB_MSG_WPR: Invalid cross-domain sender");
    }

    /**
     * @dev Claim funds that exist on the l2 messenger wrapper alias address
     * @notice Do not use state variables here as this is to be used when passing in precise values
     */
    function claimL2Funds(
        address _recipient,
        uint256 _l2CallValue,
        uint256 _maxSubmissionCost,
        uint256 _maxGas,
        uint256 _gasPriceBid
    )
        public
        onlyOwner
    {
        l1MessengerAddress.createRetryableTicket(
            _recipient,
            _l2CallValue,
            _maxSubmissionCost,
            _recipient,
            _recipient,
            _maxGas,
            _gasPriceBid,
            ""
        );
    }

    /// @notice Utility function that converts the msg.sender viewed in the L2 to the
    /// address in the L1 that submitted a tx to the inbox
    /// @param l1Address L2 address as viewed in msg.sender
    /// @return The address in the L1 that triggered the tx to L2
    function applyL1ToL2Alias(address l1Address) internal pure returns (address) {
        return address(uint160(l1Address) + offset);
    }

    /* ========== External Config Management Functions ========== */

    function setMaxSubmissionCost(uint256 _newMaxSubmissionCost) external onlyOwner {
        maxSubmissionCost = _newMaxSubmissionCost;
    }

    function setL1MessengerWrapperAlias(address _newL1MessengerWrapperAlias) external onlyOwner {
        l1MessengerWrapperAlias = _newL1MessengerWrapperAlias;
    }

    function setMaxGas(uint256 _newMaxGas) external onlyOwner {
        maxGas = _newMaxGas;
    }

    function setGasPriceBid(uint256 _newGasPriceBid) external onlyOwner {
        gasPriceBid = _newGasPriceBid;
    }
}

File 30 of 72 : IInbox.sol
// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./IBridge.sol";

interface IInbox {
    function sendL2Message(bytes calldata messageData) external returns (uint256);
    function bridge() external view returns (IBridge);
    function createRetryableTicket(
        address destAddr,
        uint256 l2CallValue,
        uint256 maxSubmissionCost,
        address excessFeeRefundAddress,
        address callValueRefundAddress,
        uint256 maxGas,
        uint256 gasPriceBid,
        bytes calldata data
    ) external payable returns (uint256);
}

File 31 of 72 : IBridge.sol
// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface IBridge {
    function activeOutbox() external view returns (address);
}

File 32 of 72 : IOutbox.sol
// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface IOutbox {
    function l2ToL1Sender() external view returns (address);
}

File 33 of 72 : mockArbitrum_L1_ERC20_Bridge.sol
//SPDX-License-Identifier: Unlicense
// @unsupported: ovm
pragma solidity >0.6.0 <0.8.0;

import { MockERC20 } from "../MockERC20.sol";
import { IInbox } from "../../interfaces/arbitrum/messengers//IInbox.sol";

contract Arbitrum_L1_ERC20_Bridge {
    IInbox public messenger;
    event Deposit(address indexed _sender, uint256 _amount);

    constructor (
        address _messenger
    ) public {
        messenger = IInbox(_messenger);
    }

    function deposit(
        address _l1TokenAddress,
        address _l2TokenAddress,
        address _depositor,
        uint256 _amount
    ) public {
        MockERC20(_l1TokenAddress).transferFrom(
            _depositor,
            address(this),
            _amount
        );

        // generate encoded calldata to be executed on L2
        bytes memory message = abi.encodeWithSignature(
            "mint(address,uint256)",
            _depositor,
            _amount
        );

        uint256 maxGas = 100000000000;
        messenger.createRetryableTicket(
            _l2TokenAddress,
            0,
            0,
            tx.origin,
            address(0),
            maxGas,
            0,
            message
        );

        emit Deposit(_depositor, _amount);
    }

    function withdraw(
        address _l1TokenAddress,
        address _withdrawer,
        uint256 _amount
    ) public {
        MockERC20(_l1TokenAddress).transfer(_withdrawer, _amount);
    }
}

File 34 of 72 : MockERC20.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MockERC20 is ERC20 {
    constructor(string memory _name, string memory _symbol) public ERC20(_name, _symbol) {}

    function mint(address _recipient, uint256 _amount) public {
        _mint(_recipient, _amount);
    }

    function burn(address _recipient, uint256 _amount) public {
        _burn(_recipient, _amount);
    }
}

File 35 of 72 : mockOVM_L2_ERC20_Bridge.sol
//SPDX-License-Identifier: Unlicense
pragma solidity >0.6.0 <0.8.0;

import { MockERC20 } from "../MockERC20.sol";
import { iAbs_BaseCrossDomainMessenger } from "@eth-optimism/contracts/build/contracts/iOVM/bridge/messaging/iAbs_BaseCrossDomainMessenger.sol";

contract OVM_L2_ERC20_Bridge {
    address public l1ERC20BridgeAddress;
    iAbs_BaseCrossDomainMessenger public l2Messenger;

    constructor (
        address _l2Messenger,
        address _l1ERC20BridgeAddress
    ) public {
        l2Messenger = iAbs_BaseCrossDomainMessenger(_l2Messenger);
        l1ERC20BridgeAddress = _l1ERC20BridgeAddress;
    }

    function withdraw(address _l1TokenAddress, address _l2TokenAddress, uint256 _amount) public {
        MockERC20(_l2TokenAddress).burn(msg.sender, _amount);

        // generate encoded calldata to be executed on L1
        bytes memory message = abi.encodeWithSignature(
            "withdraw(address,address,uint256)",
            _l1TokenAddress,
            msg.sender,
            _amount
        );

        // send the message over to the L1CrossDomainMessenger
        uint32 gasLimit = 2500000;
        l2Messenger.sendMessage(l1ERC20BridgeAddress, message, gasLimit);
    }
}

File 36 of 72 : iAbs_BaseCrossDomainMessenger.sol
// SPDX-License-Identifier: MIT
pragma solidity >0.5.0 <0.8.0;
pragma experimental ABIEncoderV2;

/**
 * @title iAbs_BaseCrossDomainMessenger
 */
interface iAbs_BaseCrossDomainMessenger {

    /**********
     * Events *
     **********/
    event SentMessage(bytes message);
    event RelayedMessage(bytes32 msgHash);

    /**********************
     * Contract Variables *
     **********************/
    function xDomainMessageSender() external view returns (address);

    /********************
     * Public Functions *
     ********************/

    /**
     * Sends a cross domain message to the target messenger.
     * @param _target Target contract address.
     * @param _message Message to send to the target.
     * @param _gasLimit Gas limit for the provided message.
     */
    function sendMessage(
        address _target,
        bytes calldata _message,
        uint32 _gasLimit
    ) external;
}

File 37 of 72 : mockOVM_L1_ERC20_Bridge.sol
//SPDX-License-Identifier: Unlicense
pragma solidity >0.6.0 <0.8.0;

import { MockERC20 } from "../MockERC20.sol";
import { iAbs_BaseCrossDomainMessenger } from "@eth-optimism/contracts/build/contracts/iOVM/bridge/messaging/iAbs_BaseCrossDomainMessenger.sol";

contract OVM_L1_ERC20_Bridge {
    iAbs_BaseCrossDomainMessenger public messenger;
    event Deposit(address indexed _sender, uint256 _amount);

    constructor (
        address _messenger
    ) public {
        messenger = iAbs_BaseCrossDomainMessenger(_messenger);
    }

    function deposit(
        address _l1TokenAddress,
        address _l2TokenAddress,
        address _depositor,
        uint256 _amount
    ) public {
        MockERC20(_l1TokenAddress).transferFrom(
            _depositor,
            address(this),
            _amount
        );

        // generate encoded calldata to be executed on L2
        bytes memory message = abi.encodeWithSignature(
            "mint(address,uint256)",
            _depositor,
            _amount
        );

        uint32 gasLimit = 9000000;
        messenger.sendMessage(_l2TokenAddress, message, gasLimit);

        emit Deposit(_depositor, _amount);
    }

    function withdraw(
        address _l1TokenAddress,
        address _withdrawer,
        uint256 _amount
    ) public {
        MockERC20(_l1TokenAddress).transfer(_withdrawer, _amount);
    }
}

File 38 of 72 : mockArbitrum_L2_ERC20_Bridge.sol
//SPDX-License-Identifier: Unlicense
pragma solidity >0.6.0 <0.8.0;

import { MockERC20 } from "../MockERC20.sol";
import { IArbSys } from "../../interfaces/arbitrum/messengers/IArbSys.sol";

contract Arbitrum_L2_ERC20_Bridge {
    address public l1ERC20BridgeAddress;
    IArbSys public l2Messenger;

    constructor (
        address _l2Messenger,
        address _l1ERC20BridgeAddress
    ) public {
        l2Messenger = IArbSys(_l2Messenger);
        l1ERC20BridgeAddress = _l1ERC20BridgeAddress;
    }

    function withdraw(address _l1TokenAddress, address _l2TokenAddress, uint256 _amount) public {
        MockERC20(_l2TokenAddress).burn(msg.sender, _amount);

        // generate encoded calldata to be executed on L1
        bytes memory message = abi.encodeWithSignature(
            "withdraw(address,address,uint256)",
            _l1TokenAddress,
            msg.sender,
            _amount
        );

        l2Messenger.sendTxToL1(
            l1ERC20BridgeAddress,
            message
        );
    }
}

File 39 of 72 : IArbSys.sol
// SPDX-License-Identifier: Apache-2.0

pragma solidity >=0.4.21 <0.7.0;

interface IArbSys {
    function sendTxToL1(address destAddr, bytes calldata calldataForL1) external payable;
}

File 40 of 72 : L2_ArbitrumBridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../interfaces/arbitrum/messengers/IArbSys.sol";
import "./L2_Bridge.sol";

/**
 * @dev An L2_Bridge for Arbitrum - https://developer.offchainlabs.com/
 */

contract L2_ArbitrumBridge is L2_Bridge {
    IArbSys public messenger;

    constructor (
        IArbSys _messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders
    )
        public
        L2_Bridge(
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders
        )
    {
        messenger = _messenger;
    }

    function _sendCrossDomainMessage(bytes memory message) internal override {
        messenger.sendTxToL1(
            l1BridgeAddress,
            message
        );
    }

    function _verifySender(address expectedSender) internal override {
        require(msg.sender == expectedSender, "L2_ARB_BRG: Caller is not the expected sender");
    }

    /**
     * @dev Allows the L1 Bridge to set the messenger
     * @param _messenger The new messenger address
     */
    function setMessenger(IArbSys _messenger) external onlyGovernance {
        messenger = _messenger;
    }
}

File 41 of 72 : Mock_L2_ArbitrumBridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/L2_ArbitrumBridge.sol";

contract Mock_L2_ArbitrumBridge is L2_ArbitrumBridge {
    uint256 private chainId;

    constructor (
        uint256 _chainId,
        IArbSys messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders
    )
        public
        L2_ArbitrumBridge(
            messenger,
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders
        )
    {
        chainId = _chainId;
    }

    function getChainId() public override view returns (uint256) {
        return chainId;
    }
}

File 42 of 72 : ISwapGuarded.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "./IAllowlist.sol";

interface ISwapGuarded {
    // pool data view functions
    function getA() external view returns (uint256);

    function getAllowlist() external view returns (IAllowlist);

    function getToken(uint8 index) external view returns (IERC20);

    function getTokenIndex(address tokenAddress) external view returns (uint8);

    function getTokenBalance(uint8 index) external view returns (uint256);

    function getVirtualPrice() external view returns (uint256);

    function isGuarded() external view returns (bool);

    // min return calculation functions
    function calculateSwap(
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx
    ) external view returns (uint256);

    function calculateTokenAmount(uint256[] calldata amounts, bool deposit)
        external
        view
        returns (uint256);

    function calculateRemoveLiquidity(uint256 amount)
        external
        view
        returns (uint256[] memory);

    function calculateRemoveLiquidityOneToken(
        uint256 tokenAmount,
        uint8 tokenIndex
    ) external view returns (uint256 availableTokenAmount);

    // state modifying functions
    function swap(
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx,
        uint256 minDy,
        uint256 deadline
    ) external returns (uint256);

    function addLiquidity(
        uint256[] calldata amounts,
        uint256 minToMint,
        uint256 deadline,
        bytes32[] calldata merkleProof
    ) external returns (uint256);

    function removeLiquidity(
        uint256 amount,
        uint256[] calldata minAmounts,
        uint256 deadline
    ) external returns (uint256[] memory);

    function removeLiquidityOneToken(
        uint256 tokenAmount,
        uint8 tokenIndex,
        uint256 minAmount,
        uint256 deadline
    ) external returns (uint256);

    function removeLiquidityImbalance(
        uint256[] calldata amounts,
        uint256 maxBurnAmount,
        uint256 deadline
    ) external returns (uint256);

    // withdraw fee update function
    function updateUserWithdrawFee(address recipient, uint256 transferAmount)
        external;
}

File 43 of 72 : IAllowlist.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

interface IAllowlist {
    function getPoolAccountLimit(address poolAddress)
        external
        view
        returns (uint256);

    function getPoolCap(address poolAddress) external view returns (uint256);

    function verifyAddress(address account, bytes32[] calldata merkleProof)
        external
        returns (bool);
}

File 44 of 72 : ISwap.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "./IAllowlist.sol";

interface ISwap {
    // pool data view functions
    function getA() external view returns (uint256);

    function getAllowlist() external view returns (IAllowlist);

    function getToken(uint8 index) external view returns (IERC20);

    function getTokenIndex(address tokenAddress) external view returns (uint8);

    function getTokenBalance(uint8 index) external view returns (uint256);

    function getVirtualPrice() external view returns (uint256);

    function isGuarded() external view returns (bool);

    // min return calculation functions
    function calculateSwap(
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx
    ) external view returns (uint256);

    function calculateTokenAmount(uint256[] calldata amounts, bool deposit)
        external
        view
        returns (uint256);

    function calculateRemoveLiquidity(uint256 amount)
        external
        view
        returns (uint256[] memory);

    function calculateRemoveLiquidityOneToken(
        uint256 tokenAmount,
        uint8 tokenIndex
    ) external view returns (uint256 availableTokenAmount);

    // state modifying functions
    function initialize(
        IERC20[] memory pooledTokens,
        uint8[] memory decimals,
        string memory lpTokenName,
        string memory lpTokenSymbol,
        uint256 a,
        uint256 fee,
        uint256 adminFee,
        uint256 withdrawFee
    ) external;

    function swap(
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx,
        uint256 minDy,
        uint256 deadline
    ) external returns (uint256);

    function addLiquidity(
        uint256[] calldata amounts,
        uint256 minToMint,
        uint256 deadline
    ) external returns (uint256);

    function removeLiquidity(
        uint256 amount,
        uint256[] calldata minAmounts,
        uint256 deadline
    ) external returns (uint256[] memory);

    function removeLiquidityOneToken(
        uint256 tokenAmount,
        uint8 tokenIndex,
        uint256 minAmount,
        uint256 deadline
    ) external returns (uint256);

    function removeLiquidityImbalance(
        uint256[] calldata amounts,
        uint256 maxBurnAmount,
        uint256 deadline
    ) external returns (uint256);

    // withdraw fee update function
    function updateUserWithdrawFee(address recipient, uint256 transferAmount)
        external;
}

File 45 of 72 : ISwapFlashLoan.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "./ISwap.sol";

interface ISwapFlashLoan is ISwap {
    function flashLoan(
        address receiver,
        IERC20 token,
        uint256 amount,
        bytes memory params
    ) external;
}

File 46 of 72 : LPToken.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts/token/ERC20/ERC20Burnable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "./interfaces/ISwap.sol";

/**
 * @title Liquidity Provider Token
 * @notice This token is an ERC20 detailed token with added capability to be minted by the owner.
 * It is used to represent user's shares when providing liquidity to swap contracts.
 */
contract LPToken is ERC20Burnable, Ownable {
    using SafeMath for uint256;

    // Address of the swap contract that owns this LP token. When a user adds liquidity to the swap contract,
    // they receive a proportionate amount of this LPToken.
    ISwap public swap;

    /**
     * @notice Deploys LPToken contract with given name, symbol, and decimals
     * @dev the caller of this constructor will become the owner of this contract
     * @param name_ name of this token
     * @param symbol_ symbol of this token
     * @param decimals_ number of decimals this token will be based on
     */
    constructor(
        string memory name_,
        string memory symbol_,
        uint8 decimals_
    ) public ERC20(name_, symbol_) {
        _setupDecimals(decimals_);
        swap = ISwap(_msgSender());
    }

    /**
     * @notice Mints the given amount of LPToken to the recipient.
     * @dev only owner can call this mint function
     * @param recipient address of account to receive the tokens
     * @param amount amount of tokens to mint
     */
    function mint(address recipient, uint256 amount) external onlyOwner {
        require(amount != 0, "amount == 0");
        _mint(recipient, amount);
    }

    /**
     * @dev Overrides ERC20._beforeTokenTransfer() which get called on every transfers including
     * minting and burning. This ensures that swap.updateUserWithdrawFees are called everytime.
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal override(ERC20) {
        super._beforeTokenTransfer(from, to, amount);
        swap.updateUserWithdrawFee(to, amount);
    }
}

File 47 of 72 : ERC20Burnable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../../utils/Context.sol";
import "./ERC20.sol";

/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    using SafeMath for uint256;

    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(account, amount);
    }
}

File 48 of 72 : SwapUtils.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "./LPToken.sol";
import "./MathUtils.sol";

/**
 * @title SwapUtils library
 * @notice A library to be used within Swap.sol. Contains functions responsible for custody and AMM functionalities.
 * @dev Contracts relying on this library must initialize SwapUtils.Swap struct then use this library
 * for SwapUtils.Swap struct. Note that this library contains both functions called by users and admins.
 * Admin functions should be protected within contracts using this library.
 */
library SwapUtils {
    using SafeERC20 for IERC20;
    using SafeMath for uint256;
    using MathUtils for uint256;

    /*** EVENTS ***/

    event TokenSwap(
        address indexed buyer,
        uint256 tokensSold,
        uint256 tokensBought,
        uint128 soldId,
        uint128 boughtId
    );
    event AddLiquidity(
        address indexed provider,
        uint256[] tokenAmounts,
        uint256[] fees,
        uint256 invariant,
        uint256 lpTokenSupply
    );
    event RemoveLiquidity(
        address indexed provider,
        uint256[] tokenAmounts,
        uint256 lpTokenSupply
    );
    event RemoveLiquidityOne(
        address indexed provider,
        uint256 lpTokenAmount,
        uint256 lpTokenSupply,
        uint256 boughtId,
        uint256 tokensBought
    );
    event RemoveLiquidityImbalance(
        address indexed provider,
        uint256[] tokenAmounts,
        uint256[] fees,
        uint256 invariant,
        uint256 lpTokenSupply
    );
    // event NewAdminFee(uint256 newAdminFee);
    // event NewSwapFee(uint256 newSwapFee);
    // event NewWithdrawFee(uint256 newWithdrawFee);
    // event RampA(
    //     uint256 oldA,
    //     uint256 newA,
    //     uint256 initialTime,
    //     uint256 futureTime
    // );
    // event StopRampA(uint256 currentA, uint256 time);

    struct Swap {
        // variables around the ramp management of A,
        // the amplification coefficient * n * (n - 1)
        // see https://www.curve.fi/stableswap-paper.pdf for details
        uint256 initialA;
        uint256 futureA;
        uint256 initialATime;
        uint256 futureATime;
        // fee calculation
        uint256 swapFee;
        uint256 adminFee;
        uint256 defaultWithdrawFee;
        LPToken lpToken;
        // contract references for all tokens being pooled
        IERC20[] pooledTokens;
        // multipliers for each pooled token's precision to get to POOL_PRECISION_DECIMALS
        // for example, TBTC has 18 decimals, so the multiplier should be 1. WBTC
        // has 8, so the multiplier should be 10 ** 18 / 10 ** 8 => 10 ** 10
        uint256[] tokenPrecisionMultipliers;
        // the pool balance of each token, in the token's precision
        // the contract's actual token balance might differ
        uint256[] balances;
        mapping(address => uint256) depositTimestamp;
        mapping(address => uint256) withdrawFeeMultiplier;
    }

    // Struct storing variables used in calculations in the
    // calculateWithdrawOneTokenDY function to avoid stack too deep errors
    struct CalculateWithdrawOneTokenDYInfo {
        uint256 d0;
        uint256 d1;
        uint256 newY;
        uint256 feePerToken;
        uint256 preciseA;
    }

    // Struct storing variables used in calculation in addLiquidity function
    // to avoid stack too deep error
    struct AddLiquidityInfo {
        uint256 d0;
        uint256 d1;
        uint256 d2;
        uint256 preciseA;
    }

    // Struct storing variables used in calculation in removeLiquidityImbalance function
    // to avoid stack too deep error
    struct RemoveLiquidityImbalanceInfo {
        uint256 d0;
        uint256 d1;
        uint256 d2;
        uint256 preciseA;
    }

    // the precision all pools tokens will be converted to
    uint8 public constant POOL_PRECISION_DECIMALS = 18;

    // the denominator used to calculate admin and LP fees. For example, an
    // LP fee might be something like tradeAmount.mul(fee).div(FEE_DENOMINATOR)
    uint256 private constant FEE_DENOMINATOR = 10**10;

    // Max swap fee is 1% or 100bps of each swap
    uint256 public constant MAX_SWAP_FEE = 10**8;

    // Max adminFee is 100% of the swapFee
    // adminFee does not add additional fee on top of swapFee
    // Instead it takes a certain % of the swapFee. Therefore it has no impact on the
    // users but only on the earnings of LPs
    uint256 public constant MAX_ADMIN_FEE = 10**10;

    // Max withdrawFee is 1% of the value withdrawn
    // Fee will be redistributed to the LPs in the pool, rewarding
    // long term providers.
    uint256 public constant MAX_WITHDRAW_FEE = 10**8;

    // Constant value used as max loop limit
    uint256 private constant MAX_LOOP_LIMIT = 256;

    // Constant values used in ramping A calculations
    uint256 public constant A_PRECISION = 100;
    uint256 public constant MAX_A = 10**6;
    uint256 private constant MAX_A_CHANGE = 2;
    uint256 private constant MIN_RAMP_TIME = 14 days;

    /*** VIEW & PURE FUNCTIONS ***/

    /**
     * @notice Return A, the amplification coefficient * n * (n - 1)
     * @dev See the StableSwap paper for details
     * @param self Swap struct to read from
     * @return A parameter
     */
    function getA(Swap storage self) external view returns (uint256) {
        return _getA(self);
    }

    /**
     * @notice Return A, the amplification coefficient * n * (n - 1)
     * @dev See the StableSwap paper for details
     * @param self Swap struct to read from
     * @return A parameter
     */
    function _getA(Swap storage self) internal view returns (uint256) {
        return _getAPrecise(self).div(A_PRECISION);
    }

    /**
     * @notice Return A in its raw precision
     * @dev See the StableSwap paper for details
     * @param self Swap struct to read from
     * @return A parameter in its raw precision form
     */
    function getAPrecise(Swap storage self) external view returns (uint256) {
        return _getAPrecise(self);
    }

    /**
     * @notice Calculates and returns A based on the ramp settings
     * @dev See the StableSwap paper for details
     * @param self Swap struct to read from
     * @return A parameter in its raw precision form
     */
    function _getAPrecise(Swap storage self) internal view returns (uint256) {
        uint256 t1 = self.futureATime; // time when ramp is finished
        uint256 a1 = self.futureA; // final A value when ramp is finished

        if (block.timestamp < t1) {
            uint256 t0 = self.initialATime; // time when ramp is started
            uint256 a0 = self.initialA; // initial A value when ramp is started
            if (a1 > a0) {
                // a0 + (a1 - a0) * (block.timestamp - t0) / (t1 - t0)
                return
                    a0.add(
                        a1.sub(a0).mul(block.timestamp.sub(t0)).div(t1.sub(t0))
                    );
            } else {
                // a0 - (a0 - a1) * (block.timestamp - t0) / (t1 - t0)
                return
                    a0.sub(
                        a0.sub(a1).mul(block.timestamp.sub(t0)).div(t1.sub(t0))
                    );
            }
        } else {
            return a1;
        }
    }

    /**
     * @notice Retrieves the timestamp of last deposit made by the given address
     * @param self Swap struct to read from
     * @return timestamp of last deposit
     */
    function getDepositTimestamp(Swap storage self, address user)
        external
        view
        returns (uint256)
    {
        return self.depositTimestamp[user];
    }

    /**
     * @notice Calculate the dy, the amount of selected token that user receives and
     * the fee of withdrawing in one token
     * @param account the address that is withdrawing
     * @param tokenAmount the amount to withdraw in the pool's precision
     * @param tokenIndex which token will be withdrawn
     * @param self Swap struct to read from
     * @return the amount of token user will receive and the associated swap fee
     */
    function calculateWithdrawOneToken(
        Swap storage self,
        address account,
        uint256 tokenAmount,
        uint8 tokenIndex
    ) public view returns (uint256, uint256) {
        uint256 dy;
        uint256 newY;

        (dy, newY) = calculateWithdrawOneTokenDY(self, tokenIndex, tokenAmount);

        // dy_0 (without fees)
        // dy, dy_0 - dy

        uint256 dySwapFee =
            _xp(self)[tokenIndex]
                .sub(newY)
                .div(self.tokenPrecisionMultipliers[tokenIndex])
                .sub(dy);

        dy = dy
            .mul(
            FEE_DENOMINATOR.sub(calculateCurrentWithdrawFee(self, account))
        )
            .div(FEE_DENOMINATOR);

        return (dy, dySwapFee);
    }

    /**
     * @notice Calculate the dy of withdrawing in one token
     * @param self Swap struct to read from
     * @param tokenIndex which token will be withdrawn
     * @param tokenAmount the amount to withdraw in the pools precision
     * @return the d and the new y after withdrawing one token
     */
    function calculateWithdrawOneTokenDY(
        Swap storage self,
        uint8 tokenIndex,
        uint256 tokenAmount
    ) internal view returns (uint256, uint256) {
        require(
            tokenIndex < self.pooledTokens.length,
            "Token index out of range"
        );

        // Get the current D, then solve the stableswap invariant
        // y_i for D - tokenAmount
        uint256[] memory xp = _xp(self);
        CalculateWithdrawOneTokenDYInfo memory v =
            CalculateWithdrawOneTokenDYInfo(0, 0, 0, 0, 0);
        v.preciseA = _getAPrecise(self);
        v.d0 = getD(xp, v.preciseA);
        v.d1 = v.d0.sub(tokenAmount.mul(v.d0).div(self.lpToken.totalSupply()));

        require(tokenAmount <= xp[tokenIndex], "Withdraw exceeds available");

        v.newY = getYD(v.preciseA, tokenIndex, xp, v.d1);

        uint256[] memory xpReduced = new uint256[](xp.length);

        v.feePerToken = _feePerToken(self);
        for (uint256 i = 0; i < self.pooledTokens.length; i++) {
            uint256 xpi = xp[i];
            // if i == tokenIndex, dxExpected = xp[i] * d1 / d0 - newY
            // else dxExpected = xp[i] - (xp[i] * d1 / d0)
            // xpReduced[i] -= dxExpected * fee / FEE_DENOMINATOR
            xpReduced[i] = xpi.sub(
                (
                    (i == tokenIndex)
                        ? xpi.mul(v.d1).div(v.d0).sub(v.newY)
                        : xpi.sub(xpi.mul(v.d1).div(v.d0))
                )
                    .mul(v.feePerToken)
                    .div(FEE_DENOMINATOR)
            );
        }

        uint256 dy =
            xpReduced[tokenIndex].sub(
                getYD(v.preciseA, tokenIndex, xpReduced, v.d1)
            );
        dy = dy.sub(1).div(self.tokenPrecisionMultipliers[tokenIndex]);

        return (dy, v.newY);
    }

    /**
     * @notice Calculate the price of a token in the pool with given
     * precision-adjusted balances and a particular D.
     *
     * @dev This is accomplished via solving the invariant iteratively.
     * See the StableSwap paper and Curve.fi implementation for further details.
     *
     * x_1**2 + x1 * (sum' - (A*n**n - 1) * D / (A * n**n)) = D ** (n + 1) / (n ** (2 * n) * prod' * A)
     * x_1**2 + b*x_1 = c
     * x_1 = (x_1**2 + c) / (2*x_1 + b)
     *
     * @param a the amplification coefficient * n * (n - 1). See the StableSwap paper for details.
     * @param tokenIndex Index of token we are calculating for.
     * @param xp a precision-adjusted set of pool balances. Array should be
     * the same cardinality as the pool.
     * @param d the stableswap invariant
     * @return the price of the token, in the same precision as in xp
     */
    function getYD(
        uint256 a,
        uint8 tokenIndex,
        uint256[] memory xp,
        uint256 d
    ) internal pure returns (uint256) {
        uint256 numTokens = xp.length;
        require(tokenIndex < numTokens, "Token not found");

        uint256 c = d;
        uint256 s;
        uint256 nA = a.mul(numTokens);

        for (uint256 i = 0; i < numTokens; i++) {
            if (i != tokenIndex) {
                s = s.add(xp[i]);
                c = c.mul(d).div(xp[i].mul(numTokens));
                // If we were to protect the division loss we would have to keep the denominator separate
                // and divide at the end. However this leads to overflow with large numTokens or/and D.
                // c = c * D * D * D * ... overflow!
            }
        }
        c = c.mul(d).mul(A_PRECISION).div(nA.mul(numTokens));

        uint256 b = s.add(d.mul(A_PRECISION).div(nA));
        uint256 yPrev;
        uint256 y = d;
        for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) {
            yPrev = y;
            y = y.mul(y).add(c).div(y.mul(2).add(b).sub(d));
            if (y.within1(yPrev)) {
                return y;
            }
        }
        revert("Approximation did not converge");
    }

    /**
     * @notice Get D, the StableSwap invariant, based on a set of balances and a particular A.
     * @param xp a precision-adjusted set of pool balances. Array should be the same cardinality
     * as the pool.
     * @param a the amplification coefficient * n * (n - 1) in A_PRECISION.
     * See the StableSwap paper for details
     * @return the invariant, at the precision of the pool
     */
    function getD(uint256[] memory xp, uint256 a)
        internal
        pure
        returns (uint256)
    {
        uint256 numTokens = xp.length;
        uint256 s;
        for (uint256 i = 0; i < numTokens; i++) {
            s = s.add(xp[i]);
        }
        if (s == 0) {
            return 0;
        }

        uint256 prevD;
        uint256 d = s;
        uint256 nA = a.mul(numTokens);

        for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) {
            uint256 dP = d;
            for (uint256 j = 0; j < numTokens; j++) {
                dP = dP.mul(d).div(xp[j].mul(numTokens));
                // If we were to protect the division loss we would have to keep the denominator separate
                // and divide at the end. However this leads to overflow with large numTokens or/and D.
                // dP = dP * D * D * D * ... overflow!
            }
            prevD = d;
            d = nA.mul(s).div(A_PRECISION).add(dP.mul(numTokens)).mul(d).div(
                nA.sub(A_PRECISION).mul(d).div(A_PRECISION).add(
                    numTokens.add(1).mul(dP)
                )
            );
            if (d.within1(prevD)) {
                return d;
            }
        }

        // Convergence should occur in 4 loops or less. If this is reached, there may be something wrong
        // with the pool. If this were to occur repeatedly, LPs should withdraw via `removeLiquidity()`
        // function which does not rely on D.
        revert("D does not converge");
    }

    /**
     * @notice Get D, the StableSwap invariant, based on self Swap struct
     * @param self Swap struct to read from
     * @return The invariant, at the precision of the pool
     */
    function getD(Swap storage self) internal view returns (uint256) {
        return getD(_xp(self), _getAPrecise(self));
    }

    /**
     * @notice Given a set of balances and precision multipliers, return the
     * precision-adjusted balances.
     *
     * @param balances an array of token balances, in their native precisions.
     * These should generally correspond with pooled tokens.
     *
     * @param precisionMultipliers an array of multipliers, corresponding to
     * the amounts in the balances array. When multiplied together they
     * should yield amounts at the pool's precision.
     *
     * @return an array of amounts "scaled" to the pool's precision
     */
    function _xp(
        uint256[] memory balances,
        uint256[] memory precisionMultipliers
    ) internal pure returns (uint256[] memory) {
        uint256 numTokens = balances.length;
        require(
            numTokens == precisionMultipliers.length,
            "Balances must match multipliers"
        );
        uint256[] memory xp = new uint256[](numTokens);
        for (uint256 i = 0; i < numTokens; i++) {
            xp[i] = balances[i].mul(precisionMultipliers[i]);
        }
        return xp;
    }

    /**
     * @notice Return the precision-adjusted balances of all tokens in the pool
     * @param self Swap struct to read from
     * @param balances array of balances to scale
     * @return balances array "scaled" to the pool's precision, allowing
     * them to be more easily compared.
     */
    function _xp(Swap storage self, uint256[] memory balances)
        internal
        view
        returns (uint256[] memory)
    {
        return _xp(balances, self.tokenPrecisionMultipliers);
    }

    /**
     * @notice Return the precision-adjusted balances of all tokens in the pool
     * @param self Swap struct to read from
     * @return the pool balances "scaled" to the pool's precision, allowing
     * them to be more easily compared.
     */
    function _xp(Swap storage self) internal view returns (uint256[] memory) {
        return _xp(self.balances, self.tokenPrecisionMultipliers);
    }

    /**
     * @notice Get the virtual price, to help calculate profit
     * @param self Swap struct to read from
     * @return the virtual price, scaled to precision of POOL_PRECISION_DECIMALS
     */
    function getVirtualPrice(Swap storage self)
        external
        view
        returns (uint256)
    {
        uint256 d = getD(_xp(self), _getAPrecise(self));
        uint256 supply = self.lpToken.totalSupply();
        if (supply > 0) {
            return
                d.mul(10**uint256(ERC20(self.lpToken).decimals())).div(supply);
        }
        return 0;
    }

    /**
     * @notice Calculate the new balances of the tokens given the indexes of the token
     * that is swapped from (FROM) and the token that is swapped to (TO).
     * This function is used as a helper function to calculate how much TO token
     * the user should receive on swap.
     *
     * @param self Swap struct to read from
     * @param tokenIndexFrom index of FROM token
     * @param tokenIndexTo index of TO token
     * @param x the new total amount of FROM token
     * @param xp balances of the tokens in the pool
     * @return the amount of TO token that should remain in the pool
     */
    function getY(
        Swap storage self,
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 x,
        uint256[] memory xp
    ) internal view returns (uint256) {
        uint256 numTokens = self.pooledTokens.length;
        require(
            tokenIndexFrom != tokenIndexTo,
            "Can't compare token to itself"
        );
        require(
            tokenIndexFrom < numTokens && tokenIndexTo < numTokens,
            "Tokens must be in pool"
        );

        uint256 a = _getAPrecise(self);
        uint256 d = getD(xp, a);
        uint256 c = d;
        uint256 s;
        uint256 nA = numTokens.mul(a);

        uint256 _x;
        for (uint256 i = 0; i < numTokens; i++) {
            if (i == tokenIndexFrom) {
                _x = x;
            } else if (i != tokenIndexTo) {
                _x = xp[i];
            } else {
                continue;
            }
            s = s.add(_x);
            c = c.mul(d).div(_x.mul(numTokens));
            // If we were to protect the division loss we would have to keep the denominator separate
            // and divide at the end. However this leads to overflow with large numTokens or/and D.
            // c = c * D * D * D * ... overflow!
        }
        c = c.mul(d).mul(A_PRECISION).div(nA.mul(numTokens));
        uint256 b = s.add(d.mul(A_PRECISION).div(nA));
        uint256 yPrev;
        uint256 y = d;

        // iterative approximation
        for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) {
            yPrev = y;
            y = y.mul(y).add(c).div(y.mul(2).add(b).sub(d));
            if (y.within1(yPrev)) {
                return y;
            }
        }
        revert("Approximation did not converge");
    }

    /**
     * @notice Externally calculates a swap between two tokens.
     * @param self Swap struct to read from
     * @param tokenIndexFrom the token to sell
     * @param tokenIndexTo the token to buy
     * @param dx the number of tokens to sell. If the token charges a fee on transfers,
     * use the amount that gets transferred after the fee.
     * @return dy the number of tokens the user will get
     */
    function calculateSwap(
        Swap storage self,
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx
    ) external view returns (uint256 dy) {
        (dy, ) = _calculateSwap(self, tokenIndexFrom, tokenIndexTo, dx);
    }

    /**
     * @notice Internally calculates a swap between two tokens.
     *
     * @dev The caller is expected to transfer the actual amounts (dx and dy)
     * using the token contracts.
     *
     * @param self Swap struct to read from
     * @param tokenIndexFrom the token to sell
     * @param tokenIndexTo the token to buy
     * @param dx the number of tokens to sell. If the token charges a fee on transfers,
     * use the amount that gets transferred after the fee.
     * @return dy the number of tokens the user will get
     * @return dyFee the associated fee
     */
    function _calculateSwap(
        Swap storage self,
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx
    ) internal view returns (uint256 dy, uint256 dyFee) {
        uint256[] memory xp = _xp(self);
        require(
            tokenIndexFrom < xp.length && tokenIndexTo < xp.length,
            "Token index out of range"
        );
        uint256 x =
            dx.mul(self.tokenPrecisionMultipliers[tokenIndexFrom]).add(
                xp[tokenIndexFrom]
            );
        uint256 y = getY(self, tokenIndexFrom, tokenIndexTo, x, xp);
        dy = xp[tokenIndexTo].sub(y).sub(1);
        dyFee = dy.mul(self.swapFee).div(FEE_DENOMINATOR);
        dy = dy.sub(dyFee).div(self.tokenPrecisionMultipliers[tokenIndexTo]);
    }

    /**
     * @notice A simple method to calculate amount of each underlying
     * tokens that is returned upon burning given amount of
     * LP tokens
     *
     * @param account the address that is removing liquidity. required for withdraw fee calculation
     * @param amount the amount of LP tokens that would to be burned on
     * withdrawal
     * @return array of amounts of tokens user will receive
     */
    function calculateRemoveLiquidity(
        Swap storage self,
        address account,
        uint256 amount
    ) external view returns (uint256[] memory) {
        return _calculateRemoveLiquidity(self, account, amount);
    }

    function _calculateRemoveLiquidity(
        Swap storage self,
        address account,
        uint256 amount
    ) internal view returns (uint256[] memory) {
        uint256 totalSupply = self.lpToken.totalSupply();
        require(amount <= totalSupply, "Cannot exceed total supply");

        uint256 feeAdjustedAmount =
            amount
                .mul(
                FEE_DENOMINATOR.sub(calculateCurrentWithdrawFee(self, account))
            )
                .div(FEE_DENOMINATOR);

        uint256[] memory amounts = new uint256[](self.pooledTokens.length);

        for (uint256 i = 0; i < self.pooledTokens.length; i++) {
            amounts[i] = self.balances[i].mul(feeAdjustedAmount).div(
                totalSupply
            );
        }
        return amounts;
    }

    /**
     * @notice Calculate the fee that is applied when the given user withdraws.
     * Withdraw fee decays linearly over 4 weeks.
     * @param user address you want to calculate withdraw fee of
     * @return current withdraw fee of the user
     */
    function calculateCurrentWithdrawFee(Swap storage self, address user)
        public
        view
        returns (uint256)
    {
        uint256 endTime = self.depositTimestamp[user].add(4 weeks);
        if (endTime > block.timestamp) {
            uint256 timeLeftover = endTime.sub(block.timestamp);
            return
                self
                    .defaultWithdrawFee
                    .mul(self.withdrawFeeMultiplier[user])
                    .mul(timeLeftover)
                    .div(4 weeks)
                    .div(FEE_DENOMINATOR);
        }
        return 0;
    }

    /**
     * @notice A simple method to calculate prices from deposits or
     * withdrawals, excluding fees but including slippage. This is
     * helpful as an input into the various "min" parameters on calls
     * to fight front-running
     *
     * @dev This shouldn't be used outside frontends for user estimates.
     *
     * @param self Swap struct to read from
     * @param account address of the account depositing or withdrawing tokens
     * @param amounts an array of token amounts to deposit or withdrawal,
     * corresponding to pooledTokens. The amount should be in each
     * pooled token's native precision. If a token charges a fee on transfers,
     * use the amount that gets transferred after the fee.
     * @param deposit whether this is a deposit or a withdrawal
     * @return if deposit was true, total amount of lp token that will be minted and if
     * deposit was false, total amount of lp token that will be burned
     */
    function calculateTokenAmount(
        Swap storage self,
        address account,
        uint256[] calldata amounts,
        bool deposit
    ) external view returns (uint256) {
        uint256 numTokens = self.pooledTokens.length;
        uint256 a = _getAPrecise(self);
        uint256 d0 = getD(_xp(self, self.balances), a);
        uint256[] memory balances1 = self.balances;
        for (uint256 i = 0; i < numTokens; i++) {
            if (deposit) {
                balances1[i] = balances1[i].add(amounts[i]);
            } else {
                balances1[i] = balances1[i].sub(
                    amounts[i],
                    "Cannot withdraw more than available"
                );
            }
        }
        uint256 d1 = getD(_xp(self, balances1), a);
        uint256 totalSupply = self.lpToken.totalSupply();

        if (deposit) {
            return d1.sub(d0).mul(totalSupply).div(d0);
        } else {
            return
                d0.sub(d1).mul(totalSupply).div(d0).mul(FEE_DENOMINATOR).div(
                    FEE_DENOMINATOR.sub(
                        calculateCurrentWithdrawFee(self, account)
                    )
                );
        }
    }

    /**
     * @notice return accumulated amount of admin fees of the token with given index
     * @param self Swap struct to read from
     * @param index Index of the pooled token
     * @return admin balance in the token's precision
     */
    function getAdminBalance(Swap storage self, uint256 index)
        external
        view
        returns (uint256)
    {
        require(index < self.pooledTokens.length, "Token index out of range");
        return
            self.pooledTokens[index].balanceOf(address(this)).sub(
                self.balances[index]
            );
    }

    /**
     * @notice internal helper function to calculate fee per token multiplier used in
     * swap fee calculations
     * @param self Swap struct to read from
     */
    function _feePerToken(Swap storage self) internal view returns (uint256) {
        return
            self.swapFee.mul(self.pooledTokens.length).div(
                self.pooledTokens.length.sub(1).mul(4)
            );
    }

    /*** STATE MODIFYING FUNCTIONS ***/

    /**
     * @notice swap two tokens in the pool
     * @param self Swap struct to read from and write to
     * @param tokenIndexFrom the token the user wants to sell
     * @param tokenIndexTo the token the user wants to buy
     * @param dx the amount of tokens the user wants to sell
     * @param minDy the min amount the user would like to receive, or revert.
     * @return amount of token user received on swap
     */
    function swap(
        Swap storage self,
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx,
        uint256 minDy
    ) external returns (uint256) {
        require(
            dx <= self.pooledTokens[tokenIndexFrom].balanceOf(msg.sender),
            "Cannot swap more than you own"
        );

        // Transfer tokens first to see if a fee was charged on transfer
        uint256 beforeBalance =
            self.pooledTokens[tokenIndexFrom].balanceOf(address(this));
        self.pooledTokens[tokenIndexFrom].safeTransferFrom(
            msg.sender,
            address(this),
            dx
        );

        // Use the actual transferred amount for AMM math
        uint256 transferredDx =
            self.pooledTokens[tokenIndexFrom].balanceOf(address(this)).sub(
                beforeBalance
            );

        (uint256 dy, uint256 dyFee) =
            _calculateSwap(self, tokenIndexFrom, tokenIndexTo, transferredDx);
        require(dy >= minDy, "Swap didn't result in min tokens");

        uint256 dyAdminFee =
            dyFee.mul(self.adminFee).div(FEE_DENOMINATOR).div(
                self.tokenPrecisionMultipliers[tokenIndexTo]
            );

        self.balances[tokenIndexFrom] = self.balances[tokenIndexFrom].add(
            transferredDx
        );
        self.balances[tokenIndexTo] = self.balances[tokenIndexTo].sub(dy).sub(
            dyAdminFee
        );

        self.pooledTokens[tokenIndexTo].safeTransfer(msg.sender, dy);

        emit TokenSwap(
            msg.sender,
            transferredDx,
            dy,
            tokenIndexFrom,
            tokenIndexTo
        );

        return dy;
    }

    /**
     * @notice Add liquidity to the pool
     * @param self Swap struct to read from and write to
     * @param amounts the amounts of each token to add, in their native precision
     * @param minToMint the minimum LP tokens adding this amount of liquidity
     * should mint, otherwise revert. Handy for front-running mitigation
     * allowed addresses. If the pool is not in the guarded launch phase, this parameter will be ignored.
     * @return amount of LP token user received
     */
    function addLiquidity(
        Swap storage self,
        uint256[] memory amounts,
        uint256 minToMint
    ) external returns (uint256) {
        require(
            amounts.length == self.pooledTokens.length,
            "Amounts must match pooled tokens"
        );

        uint256[] memory fees = new uint256[](self.pooledTokens.length);

        // current state
        AddLiquidityInfo memory v = AddLiquidityInfo(0, 0, 0, 0);
        uint256 totalSupply = self.lpToken.totalSupply();

        if (totalSupply != 0) {
            v.d0 = getD(self);
        }
        uint256[] memory newBalances = self.balances;

        for (uint256 i = 0; i < self.pooledTokens.length; i++) {
            require(
                totalSupply != 0 || amounts[i] > 0,
                "Must supply all tokens in pool"
            );

            // Transfer tokens first to see if a fee was charged on transfer
            if (amounts[i] != 0) {
                uint256 beforeBalance =
                    self.pooledTokens[i].balanceOf(address(this));
                self.pooledTokens[i].safeTransferFrom(
                    msg.sender,
                    address(this),
                    amounts[i]
                );

                // Update the amounts[] with actual transfer amount
                amounts[i] = self.pooledTokens[i].balanceOf(address(this)).sub(
                    beforeBalance
                );
            }

            newBalances[i] = self.balances[i].add(amounts[i]);
        }

        // invariant after change
        v.preciseA = _getAPrecise(self);
        v.d1 = getD(_xp(self, newBalances), v.preciseA);
        require(v.d1 > v.d0, "D should increase");

        // updated to reflect fees and calculate the user's LP tokens
        v.d2 = v.d1;
        if (totalSupply != 0) {
            uint256 feePerToken = _feePerToken(self);
            for (uint256 i = 0; i < self.pooledTokens.length; i++) {
                uint256 idealBalance = v.d1.mul(self.balances[i]).div(v.d0);
                fees[i] = feePerToken
                    .mul(idealBalance.difference(newBalances[i]))
                    .div(FEE_DENOMINATOR);
                self.balances[i] = newBalances[i].sub(
                    fees[i].mul(self.adminFee).div(FEE_DENOMINATOR)
                );
                newBalances[i] = newBalances[i].sub(fees[i]);
            }
            v.d2 = getD(_xp(self, newBalances), v.preciseA);
        } else {
            // the initial depositor doesn't pay fees
            self.balances = newBalances;
        }

        uint256 toMint;
        if (totalSupply == 0) {
            toMint = v.d1;
        } else {
            toMint = v.d2.sub(v.d0).mul(totalSupply).div(v.d0);
        }

        require(toMint >= minToMint, "Couldn't mint min requested");

        // mint the user's LP tokens
        self.lpToken.mint(msg.sender, toMint);

        emit AddLiquidity(
            msg.sender,
            amounts,
            fees,
            v.d1,
            totalSupply.add(toMint)
        );

        return toMint;
    }

    /**
     * @notice Update the withdraw fee for `user`. If the user is currently
     * not providing liquidity in the pool, sets to default value. If not, recalculate
     * the starting withdraw fee based on the last deposit's time & amount relative
     * to the new deposit.
     *
     * @param self Swap struct to read from and write to
     * @param user address of the user depositing tokens
     * @param toMint amount of pool tokens to be minted
     */
    function updateUserWithdrawFee(
        Swap storage self,
        address user,
        uint256 toMint
    ) external {
        _updateUserWithdrawFee(self, user, toMint);
    }

    function _updateUserWithdrawFee(
        Swap storage self,
        address user,
        uint256 toMint
    ) internal {
        // If token is transferred to address 0 (or burned), don't update the fee.
        if (user == address(0)) {
            return;
        }
        if (self.defaultWithdrawFee == 0) {
            // If current fee is set to 0%, set multiplier to FEE_DENOMINATOR
            self.withdrawFeeMultiplier[user] = FEE_DENOMINATOR;
        } else {
            // Otherwise, calculate appropriate discount based on last deposit amount
            uint256 currentFee = calculateCurrentWithdrawFee(self, user);
            uint256 currentBalance = self.lpToken.balanceOf(user);

            // ((currentBalance * currentFee) + (toMint * defaultWithdrawFee)) * FEE_DENOMINATOR /
            // ((toMint + currentBalance) * defaultWithdrawFee)
            self.withdrawFeeMultiplier[user] = currentBalance
                .mul(currentFee)
                .add(toMint.mul(self.defaultWithdrawFee))
                .mul(FEE_DENOMINATOR)
                .div(toMint.add(currentBalance).mul(self.defaultWithdrawFee));
        }
        self.depositTimestamp[user] = block.timestamp;
    }

    /**
     * @notice Burn LP tokens to remove liquidity from the pool.
     * @dev Liquidity can always be removed, even when the pool is paused.
     * @param self Swap struct to read from and write to
     * @param amount the amount of LP tokens to burn
     * @param minAmounts the minimum amounts of each token in the pool
     * acceptable for this burn. Useful as a front-running mitigation
     * @return amounts of tokens the user received
     */
    function removeLiquidity(
        Swap storage self,
        uint256 amount,
        uint256[] calldata minAmounts
    ) external returns (uint256[] memory) {
        require(amount <= self.lpToken.balanceOf(msg.sender), ">LP.balanceOf");
        require(
            minAmounts.length == self.pooledTokens.length,
            "minAmounts must match poolTokens"
        );

        uint256[] memory amounts =
            _calculateRemoveLiquidity(self, msg.sender, amount);

        for (uint256 i = 0; i < amounts.length; i++) {
            require(amounts[i] >= minAmounts[i], "amounts[i] < minAmounts[i]");
            self.balances[i] = self.balances[i].sub(amounts[i]);
            self.pooledTokens[i].safeTransfer(msg.sender, amounts[i]);
        }

        self.lpToken.burnFrom(msg.sender, amount);

        emit RemoveLiquidity(msg.sender, amounts, self.lpToken.totalSupply());

        return amounts;
    }

    /**
     * @notice Remove liquidity from the pool all in one token.
     * @param self Swap struct to read from and write to
     * @param tokenAmount the amount of the lp tokens to burn
     * @param tokenIndex the index of the token you want to receive
     * @param minAmount the minimum amount to withdraw, otherwise revert
     * @return amount chosen token that user received
     */
    function removeLiquidityOneToken(
        Swap storage self,
        uint256 tokenAmount,
        uint8 tokenIndex,
        uint256 minAmount
    ) external returns (uint256) {
        uint256 totalSupply = self.lpToken.totalSupply();
        uint256 numTokens = self.pooledTokens.length;
        require(
            tokenAmount <= self.lpToken.balanceOf(msg.sender),
            ">LP.balanceOf"
        );
        require(tokenIndex < numTokens, "Token not found");

        uint256 dyFee;
        uint256 dy;

        (dy, dyFee) = calculateWithdrawOneToken(
            self,
            msg.sender,
            tokenAmount,
            tokenIndex
        );

        require(dy >= minAmount, "dy < minAmount");

        self.balances[tokenIndex] = self.balances[tokenIndex].sub(
            dy.add(dyFee.mul(self.adminFee).div(FEE_DENOMINATOR))
        );
        self.lpToken.burnFrom(msg.sender, tokenAmount);
        self.pooledTokens[tokenIndex].safeTransfer(msg.sender, dy);

        emit RemoveLiquidityOne(
            msg.sender,
            tokenAmount,
            totalSupply,
            tokenIndex,
            dy
        );

        return dy;
    }

    /**
     * @notice Remove liquidity from the pool, weighted differently than the
     * pool's current balances.
     *
     * @param self Swap struct to read from and write to
     * @param amounts how much of each token to withdraw
     * @param maxBurnAmount the max LP token provider is willing to pay to
     * remove liquidity. Useful as a front-running mitigation.
     * @return actual amount of LP tokens burned in the withdrawal
     */
    function removeLiquidityImbalance(
        Swap storage self,
        uint256[] memory amounts,
        uint256 maxBurnAmount
    ) public returns (uint256) {
        require(
            amounts.length == self.pooledTokens.length,
            "Amounts should match pool tokens"
        );
        require(
            maxBurnAmount <= self.lpToken.balanceOf(msg.sender) &&
                maxBurnAmount != 0,
            ">LP.balanceOf"
        );

        RemoveLiquidityImbalanceInfo memory v =
            RemoveLiquidityImbalanceInfo(0, 0, 0, 0);

        uint256 tokenSupply = self.lpToken.totalSupply();
        uint256 feePerToken = _feePerToken(self);

        uint256[] memory balances1 = self.balances;

        v.preciseA = _getAPrecise(self);
        v.d0 = getD(_xp(self), v.preciseA);
        for (uint256 i = 0; i < self.pooledTokens.length; i++) {
            balances1[i] = balances1[i].sub(
                amounts[i],
                "Cannot withdraw more than available"
            );
        }
        v.d1 = getD(_xp(self, balances1), v.preciseA);
        uint256[] memory fees = new uint256[](self.pooledTokens.length);

        for (uint256 i = 0; i < self.pooledTokens.length; i++) {
            uint256 idealBalance = v.d1.mul(self.balances[i]).div(v.d0);
            uint256 difference = idealBalance.difference(balances1[i]);
            fees[i] = feePerToken.mul(difference).div(FEE_DENOMINATOR);
            self.balances[i] = balances1[i].sub(
                fees[i].mul(self.adminFee).div(FEE_DENOMINATOR)
            );
            balances1[i] = balances1[i].sub(fees[i]);
        }

        v.d2 = getD(_xp(self, balances1), v.preciseA);

        uint256 tokenAmount = v.d0.sub(v.d2).mul(tokenSupply).div(v.d0);
        require(tokenAmount != 0, "Burnt amount cannot be zero");
        tokenAmount = tokenAmount.add(1).mul(FEE_DENOMINATOR).div(
            FEE_DENOMINATOR.sub(calculateCurrentWithdrawFee(self, msg.sender))
        );

        require(tokenAmount <= maxBurnAmount, "tokenAmount > maxBurnAmount");

        self.lpToken.burnFrom(msg.sender, tokenAmount);

        for (uint256 i = 0; i < self.pooledTokens.length; i++) {
            self.pooledTokens[i].safeTransfer(msg.sender, amounts[i]);
        }

        emit RemoveLiquidityImbalance(
            msg.sender,
            amounts,
            fees,
            v.d1,
            tokenSupply.sub(tokenAmount)
        );

        return tokenAmount;
    }

    // /**
    //  * @notice withdraw all admin fees to a given address
    //  * @param self Swap struct to withdraw fees from
    //  * @param to Address to send the fees to
    //  */
    // function withdrawAdminFees(Swap storage self, address to) external {
    //     for (uint256 i = 0; i < self.pooledTokens.length; i++) {
    //         IERC20 token = self.pooledTokens[i];
    //         uint256 balance =
    //             token.balanceOf(address(this)).sub(self.balances[i]);
    //         if (balance != 0) {
    //             token.safeTransfer(to, balance);
    //         }
    //     }
    // }

    // /**
    //  * @notice Sets the admin fee
    //  * @dev adminFee cannot be higher than 100% of the swap fee
    //  * @param self Swap struct to update
    //  * @param newAdminFee new admin fee to be applied on future transactions
    //  */
    // function setAdminFee(Swap storage self, uint256 newAdminFee) external {
    //     require(newAdminFee <= MAX_ADMIN_FEE, "Fee is too high");
    //     self.adminFee = newAdminFee;

    //     emit NewAdminFee(newAdminFee);
    // }

    // /**
    //  * @notice update the swap fee
    //  * @dev fee cannot be higher than 1% of each swap
    //  * @param self Swap struct to update
    //  * @param newSwapFee new swap fee to be applied on future transactions
    //  */
    // function setSwapFee(Swap storage self, uint256 newSwapFee) external {
    //     require(newSwapFee <= MAX_SWAP_FEE, "Fee is too high");
    //     self.swapFee = newSwapFee;

    //     emit NewSwapFee(newSwapFee);
    // }

    // /**
    //  * @notice update the default withdraw fee. This also affects deposits made in the past as well.
    //  * @param self Swap struct to update
    //  * @param newWithdrawFee new withdraw fee to be applied
    //  */
    // function setDefaultWithdrawFee(Swap storage self, uint256 newWithdrawFee)
    //     external
    // {
    //     require(newWithdrawFee <= MAX_WITHDRAW_FEE, "Fee is too high");
    //     self.defaultWithdrawFee = newWithdrawFee;

    //     emit NewWithdrawFee(newWithdrawFee);
    // }

    // /**
    //  * @notice Start ramping up or down A parameter towards given futureA_ and futureTime_
    //  * Checks if the change is too rapid, and commits the new A value only when it falls under
    //  * the limit range.
    //  * @param self Swap struct to update
    //  * @param futureA_ the new A to ramp towards
    //  * @param futureTime_ timestamp when the new A should be reached
    //  */
    // function rampA(
    //     Swap storage self,
    //     uint256 futureA_,
    //     uint256 futureTime_
    // ) external {
    //     require(
    //         block.timestamp >= self.initialATime.add(1 days),
    //         "Wait 1 day before starting ramp"
    //     );
    //     require(
    //         futureTime_ >= block.timestamp.add(MIN_RAMP_TIME),
    //         "Insufficient ramp time"
    //     );
    //     require(
    //         futureA_ > 0 && futureA_ < MAX_A,
    //         "futureA_ must be > 0 and < MAX_A"
    //     );

    //     uint256 initialAPrecise = _getAPrecise(self);
    //     uint256 futureAPrecise = futureA_.mul(A_PRECISION);

    //     if (futureAPrecise < initialAPrecise) {
    //         require(
    //             futureAPrecise.mul(MAX_A_CHANGE) >= initialAPrecise,
    //             "futureA_ is too small"
    //         );
    //     } else {
    //         require(
    //             futureAPrecise <= initialAPrecise.mul(MAX_A_CHANGE),
    //             "futureA_ is too large"
    //         );
    //     }

    //     self.initialA = initialAPrecise;
    //     self.futureA = futureAPrecise;
    //     self.initialATime = block.timestamp;
    //     self.futureATime = futureTime_;

    //     emit RampA(
    //         initialAPrecise,
    //         futureAPrecise,
    //         block.timestamp,
    //         futureTime_
    //     );
    // }

    // /**
    //  * @notice Stops ramping A immediately. Once this function is called, rampA()
    //  * cannot be called for another 24 hours
    //  * @param self Swap struct to update
    //  */
    // function stopRampA(Swap storage self) external {
    //     require(self.futureATime > block.timestamp, "Ramp is already stopped");
    //     uint256 currentA = _getAPrecise(self);

    //     self.initialA = currentA;
    //     self.futureA = currentA;
    //     self.initialATime = block.timestamp;
    //     self.futureATime = block.timestamp;

    //     emit StopRampA(currentA, block.timestamp);
    // }
}

File 49 of 72 : MathUtils.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

// import "@openzeppelin/contracts/math/SafeMath.sol";

/**
 * @title MathUtils library
 * @notice A library to be used in conjunction with SafeMath. Contains functions for calculating
 * differences between two uint256.
 */
library MathUtils {
    /**
     * @notice Compares a and b and returns true if the difference between a and b
     *         is less than 1 or equal to each other.
     * @param a uint256 to compare with
     * @param b uint256 to compare with
     * @return True if the difference between a and b is less than 1 or equal,
     *         otherwise return false
     */
    function within1(uint256 a, uint256 b) external pure returns (bool) {
        return (_difference(a, b) <= 1);
    }

    /**
     * @notice Calculates absolute difference between a and b
     * @param a uint256 to compare with
     * @param b uint256 to compare with
     * @return Difference between a and b
     */
    function difference(uint256 a, uint256 b) external pure returns (uint256) {
        return _difference(a, b);
    }

    /**
     * @notice Calculates absolute difference between a and b
     * @param a uint256 to compare with
     * @param b uint256 to compare with
     * @return Difference between a and b
     */
    function _difference(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a > b) {
            return a - b;
        }
        return b - a;
    }
}

File 50 of 72 : Swap.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
// import "./OwnerPausableUpgradeable.sol";
import "./SwapUtils.sol";
import "./MathUtils.sol";

/**
 * @title Swap - A StableSwap implementation in solidity.
 * @notice This contract is responsible for custody of closely pegged assets (eg. group of stablecoins)
 * and automatic market making system. Users become an LP (Liquidity Provider) by depositing their tokens
 * in desired ratios for an exchange of the pool token that represents their share of the pool.
 * Users can burn pool tokens and withdraw their share of token(s).
 *
 * Each time a swap between the pooled tokens happens, a set fee incurs which effectively gets
 * distributed to the LPs.
 *
 * In case of emergencies, admin can pause additional deposits, swaps, or single-asset withdraws - which
 * stops the ratio of the tokens in the pool from changing.
 * Users can always withdraw their tokens via multi-asset withdraws.
 *
 * @dev Most of the logic is stored as a library `SwapUtils` for the sake of reducing contract's
 * deployment size.
 */
contract Swap is ReentrancyGuardUpgradeable {
    using SafeERC20 for IERC20;
    using SafeMath for uint256;
    using MathUtils for uint256;
    using SwapUtils for SwapUtils.Swap;

    // Struct storing data responsible for automatic market maker functionalities. In order to
    // access this data, this contract uses SwapUtils library. For more details, see SwapUtils.sol
    SwapUtils.Swap public swapStorage;

    // True if the contract is initialized.
    bool private initialized = false;

    // Maps token address to an index in the pool. Used to prevent duplicate tokens in the pool.
    // getTokenIndex function also relies on this mapping to retrieve token index.
    mapping(address => uint8) private tokenIndexes;

    /*** EVENTS ***/

    // events replicated from SwapUtils to make the ABI easier for dumb
    // clients
    event TokenSwap(
        address indexed buyer,
        uint256 tokensSold,
        uint256 tokensBought,
        uint128 soldId,
        uint128 boughtId
    );
    event AddLiquidity(
        address indexed provider,
        uint256[] tokenAmounts,
        uint256[] fees,
        uint256 invariant,
        uint256 lpTokenSupply
    );
    event RemoveLiquidity(
        address indexed provider,
        uint256[] tokenAmounts,
        uint256 lpTokenSupply
    );
    event RemoveLiquidityOne(
        address indexed provider,
        uint256 lpTokenAmount,
        uint256 lpTokenSupply,
        uint256 boughtId,
        uint256 tokensBought
    );
    event RemoveLiquidityImbalance(
        address indexed provider,
        uint256[] tokenAmounts,
        uint256[] fees,
        uint256 invariant,
        uint256 lpTokenSupply
    );
    event NewAdminFee(uint256 newAdminFee);
    event NewSwapFee(uint256 newSwapFee);
    event NewWithdrawFee(uint256 newWithdrawFee);
    event RampA(
        uint256 oldA,
        uint256 newA,
        uint256 initialTime,
        uint256 futureTime
    );
    event StopRampA(uint256 currentA, uint256 time);

    /**
     * @notice Initializes this Swap contract with the given parameters.
     * This will also deploy the LPToken that represents users
     * LP position. The owner of LPToken will be this contract - which means
     * only this contract is allowed to mint new tokens.
     *
     * @param _pooledTokens an array of ERC20s this pool will accept
     * @param decimals the decimals to use for each pooled token,
     * eg 8 for WBTC. Cannot be larger than POOL_PRECISION_DECIMALS
     * @param lpTokenName the long-form name of the token to be deployed
     * @param lpTokenSymbol the short symbol for the token to be deployed
     * @param _a the amplification coefficient * n * (n - 1). See the
     * StableSwap paper for details
     * @param _fee default swap fee to be initialized with
     * @param _adminFee default adminFee to be initialized with
     * @param _withdrawFee default withdrawFee to be initialized with
     */
    function initialize(
        IERC20[] memory _pooledTokens,
        uint8[] memory decimals,
        string memory lpTokenName,
        string memory lpTokenSymbol,
        uint256 _a,
        uint256 _fee,
        uint256 _adminFee,
        uint256 _withdrawFee
    ) public virtual initializer {
        // __OwnerPausable_init();
        __ReentrancyGuard_init();
        // Check _pooledTokens and precisions parameter
        require(_pooledTokens.length > 1, "_pooledTokens.length <= 1");
        require(_pooledTokens.length <= 32, "_pooledTokens.length > 32");
        require(
            _pooledTokens.length == decimals.length,
            "_pooledTokens decimals mismatch"
        );

        uint256[] memory precisionMultipliers = new uint256[](decimals.length);

        for (uint8 i = 0; i < _pooledTokens.length; i++) {
            if (i > 0) {
                // Check if index is already used. Check if 0th element is a duplicate.
                require(
                    tokenIndexes[address(_pooledTokens[i])] == 0 &&
                        _pooledTokens[0] != _pooledTokens[i],
                    "Duplicate tokens"
                );
            }
            require(
                address(_pooledTokens[i]) != address(0),
                "The 0 address isn't an ERC-20"
            );
            require(
                decimals[i] <= SwapUtils.POOL_PRECISION_DECIMALS,
                "Token decimals exceeds max"
            );
            precisionMultipliers[i] =
                10 **
                    uint256(SwapUtils.POOL_PRECISION_DECIMALS).sub(
                        uint256(decimals[i])
                    );
            tokenIndexes[address(_pooledTokens[i])] = i;
        }

        // Check _a, _fee, _adminFee, _withdrawFee parameters
        require(_a < SwapUtils.MAX_A, "_a exceeds maximum");
        require(_fee < SwapUtils.MAX_SWAP_FEE, "_fee exceeds maximum");
        require(
            _adminFee < SwapUtils.MAX_ADMIN_FEE,
            "_adminFee exceeds maximum"
        );
        require(
            _withdrawFee < SwapUtils.MAX_WITHDRAW_FEE,
            "_withdrawFee exceeds maximum"
        );

        // Initialize swapStorage struct
        swapStorage.lpToken = new LPToken(
            lpTokenName,
            lpTokenSymbol,
            SwapUtils.POOL_PRECISION_DECIMALS
        );
        swapStorage.pooledTokens = _pooledTokens;
        swapStorage.tokenPrecisionMultipliers = precisionMultipliers;
        swapStorage.balances = new uint256[](_pooledTokens.length);
        swapStorage.initialA = _a.mul(SwapUtils.A_PRECISION);
        swapStorage.futureA = _a.mul(SwapUtils.A_PRECISION);
        swapStorage.initialATime = 0;
        swapStorage.futureATime = 0;
        swapStorage.swapFee = _fee;
        swapStorage.adminFee = _adminFee;
        swapStorage.defaultWithdrawFee = _withdrawFee;
    }

    /*** MODIFIERS ***/

    /**
     * @notice Modifier to check deadline against current timestamp
     * @param deadline latest timestamp to accept this transaction
     */
    modifier deadlineCheck(uint256 deadline) {
        require(block.timestamp <= deadline, "Deadline not met");
        _;
    }

    /*** VIEW FUNCTIONS ***/

    /**
     * @notice Return A, the amplification coefficient * n * (n - 1)
     * @dev See the StableSwap paper for details
     * @return A parameter
     */
    function getA() external view returns (uint256) {
        return swapStorage.getA();
    }

    /**
     * @notice Return A in its raw precision form
     * @dev See the StableSwap paper for details
     * @return A parameter in its raw precision form
     */
    function getAPrecise() external view returns (uint256) {
        return swapStorage.getAPrecise();
    }

    /**
     * @notice Return address of the pooled token at given index. Reverts if tokenIndex is out of range.
     * @param index the index of the token
     * @return address of the token at given index
     */
    function getToken(uint8 index) public view returns (IERC20) {
        require(index < swapStorage.pooledTokens.length, "Out of range");
        return swapStorage.pooledTokens[index];
    }

    /**
     * @notice Return the index of the given token address. Reverts if no matching
     * token is found.
     * @param tokenAddress address of the token
     * @return the index of the given token address
     */
    function getTokenIndex(address tokenAddress) public view returns (uint8) {
        uint8 index = tokenIndexes[tokenAddress];
        require(
            address(getToken(index)) == tokenAddress,
            "Token does not exist"
        );
        return index;
    }

    /**
     * @notice Return timestamp of last deposit of given address
     * @return timestamp of the last deposit made by the given address
     */
    function getDepositTimestamp(address user) external view returns (uint256) {
        return swapStorage.getDepositTimestamp(user);
    }

    /**
     * @notice Return current balance of the pooled token at given index
     * @param index the index of the token
     * @return current balance of the pooled token at given index with token's native precision
     */
    function getTokenBalance(uint8 index) external view returns (uint256) {
        require(index < swapStorage.pooledTokens.length, "Index out of range");
        return swapStorage.balances[index];
    }

    /**
     * @notice Get the virtual price, to help calculate profit
     * @return the virtual price, scaled to the POOL_PRECISION_DECIMALS
     */
    function getVirtualPrice() external view returns (uint256) {
        return swapStorage.getVirtualPrice();
    }

    /**
     * @notice Calculate amount of tokens you receive on swap
     * @param tokenIndexFrom the token the user wants to sell
     * @param tokenIndexTo the token the user wants to buy
     * @param dx the amount of tokens the user wants to sell. If the token charges
     * a fee on transfers, use the amount that gets transferred after the fee.
     * @return amount of tokens the user will receive
     */
    function calculateSwap(
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx
    ) external view returns (uint256) {
        return swapStorage.calculateSwap(tokenIndexFrom, tokenIndexTo, dx);
    }

    /**
     * @notice A simple method to calculate prices from deposits or
     * withdrawals, excluding fees but including slippage. This is
     * helpful as an input into the various "min" parameters on calls
     * to fight front-running
     *
     * @dev This shouldn't be used outside frontends for user estimates.
     *
     * @param account address that is depositing or withdrawing tokens
     * @param amounts an array of token amounts to deposit or withdrawal,
     * corresponding to pooledTokens. The amount should be in each
     * pooled token's native precision. If a token charges a fee on transfers,
     * use the amount that gets transferred after the fee.
     * @param deposit whether this is a deposit or a withdrawal
     * @return token amount the user will receive
     */
    function calculateTokenAmount(
        address account,
        uint256[] calldata amounts,
        bool deposit
    ) external view returns (uint256) {
        return swapStorage.calculateTokenAmount(account, amounts, deposit);
    }

    /**
     * @notice A simple method to calculate amount of each underlying
     * tokens that is returned upon burning given amount of LP tokens
     * @param account the address that is withdrawing tokens
     * @param amount the amount of LP tokens that would be burned on withdrawal
     * @return array of token balances that the user will receive
     */
    function calculateRemoveLiquidity(address account, uint256 amount)
        external
        view
        returns (uint256[] memory)
    {
        return swapStorage.calculateRemoveLiquidity(account, amount);
    }

    /**
     * @notice Calculate the amount of underlying token available to withdraw
     * when withdrawing via only single token
     * @param account the address that is withdrawing tokens
     * @param tokenAmount the amount of LP token to burn
     * @param tokenIndex index of which token will be withdrawn
     * @return availableTokenAmount calculated amount of underlying token
     * available to withdraw
     */
    function calculateRemoveLiquidityOneToken(
        address account,
        uint256 tokenAmount,
        uint8 tokenIndex
    ) external view returns (uint256 availableTokenAmount) {
        (availableTokenAmount, ) = swapStorage.calculateWithdrawOneToken(
            account,
            tokenAmount,
            tokenIndex
        );
    }

    /**
     * @notice Calculate the fee that is applied when the given user withdraws. The withdraw fee
     * decays linearly over period of 4 weeks. For example, depositing and withdrawing right away
     * will charge you the full amount of withdraw fee. But withdrawing after 4 weeks will charge you
     * no additional fees.
     * @dev returned value should be divided by FEE_DENOMINATOR to convert to correct decimals
     * @param user address you want to calculate withdraw fee of
     * @return current withdraw fee of the user
     */
    function calculateCurrentWithdrawFee(address user)
        external
        view
        returns (uint256)
    {
        return swapStorage.calculateCurrentWithdrawFee(user);
    }

    /**
     * @notice This function reads the accumulated amount of admin fees of the token with given index
     * @param index Index of the pooled token
     * @return admin's token balance in the token's precision
     */
    function getAdminBalance(uint256 index) external view returns (uint256) {
        return swapStorage.getAdminBalance(index);
    }

    /*** STATE MODIFYING FUNCTIONS ***/

    /**
     * @notice Swap two tokens using this pool
     * @param tokenIndexFrom the token the user wants to swap from
     * @param tokenIndexTo the token the user wants to swap to
     * @param dx the amount of tokens the user wants to swap from
     * @param minDy the min amount the user would like to receive, or revert.
     * @param deadline latest timestamp to accept this transaction
     */
    function swap(
        uint8 tokenIndexFrom,
        uint8 tokenIndexTo,
        uint256 dx,
        uint256 minDy,
        uint256 deadline
    )
        external
        nonReentrant
        // whenNotPaused
        deadlineCheck(deadline)
        returns (uint256)
    {
        return swapStorage.swap(tokenIndexFrom, tokenIndexTo, dx, minDy);
    }

    /**
     * @notice Add liquidity to the pool with the given amounts of tokens
     * @param amounts the amounts of each token to add, in their native precision
     * @param minToMint the minimum LP tokens adding this amount of liquidity
     * should mint, otherwise revert. Handy for front-running mitigation
     * @param deadline latest timestamp to accept this transaction
     * @return amount of LP token user minted and received
     */
    function addLiquidity(
        uint256[] calldata amounts,
        uint256 minToMint,
        uint256 deadline
    )
        external
        nonReentrant
        // whenNotPaused
        deadlineCheck(deadline)
        returns (uint256)
    {
        return swapStorage.addLiquidity(amounts, minToMint);
    }

    /**
     * @notice Burn LP tokens to remove liquidity from the pool. Withdraw fee that decays linearly
     * over period of 4 weeks since last deposit will apply.
     * @dev Liquidity can always be removed, even when the pool is paused.
     * @param amount the amount of LP tokens to burn
     * @param minAmounts the minimum amounts of each token in the pool
     *        acceptable for this burn. Useful as a front-running mitigation
     * @param deadline latest timestamp to accept this transaction
     * @return amounts of tokens user received
     */
    function removeLiquidity(
        uint256 amount,
        uint256[] calldata minAmounts,
        uint256 deadline
    ) external nonReentrant deadlineCheck(deadline) returns (uint256[] memory) {
        return swapStorage.removeLiquidity(amount, minAmounts);
    }

    /**
     * @notice Remove liquidity from the pool all in one token. Withdraw fee that decays linearly
     * over period of 4 weeks since last deposit will apply.
     * @param tokenAmount the amount of the token you want to receive
     * @param tokenIndex the index of the token you want to receive
     * @param minAmount the minimum amount to withdraw, otherwise revert
     * @param deadline latest timestamp to accept this transaction
     * @return amount of chosen token user received
     */
    function removeLiquidityOneToken(
        uint256 tokenAmount,
        uint8 tokenIndex,
        uint256 minAmount,
        uint256 deadline
    )
        external
        nonReentrant
        // whenNotPaused
        deadlineCheck(deadline)
        returns (uint256)
    {
        return
            swapStorage.removeLiquidityOneToken(
                tokenAmount,
                tokenIndex,
                minAmount
            );
    }

    /**
     * @notice Remove liquidity from the pool, weighted differently than the
     * pool's current balances. Withdraw fee that decays linearly
     * over period of 4 weeks since last deposit will apply.
     * @param amounts how much of each token to withdraw
     * @param maxBurnAmount the max LP token provider is willing to pay to
     * remove liquidity. Useful as a front-running mitigation.
     * @param deadline latest timestamp to accept this transaction
     * @return amount of LP tokens burned
     */
    function removeLiquidityImbalance(
        uint256[] calldata amounts,
        uint256 maxBurnAmount,
        uint256 deadline
    )
        external
        nonReentrant
        // whenNotPaused
        deadlineCheck(deadline)
        returns (uint256)
    {
        return swapStorage.removeLiquidityImbalance(amounts, maxBurnAmount);
    }

    /*** ADMIN FUNCTIONS ***/

    /**
     * @notice Updates the user withdraw fee. This function can only be called by
     * the pool token. Should be used to update the withdraw fee on transfer of pool tokens.
     * Transferring your pool token will reset the 4 weeks period. If the recipient is already
     * holding some pool tokens, the withdraw fee will be discounted in respective amounts.
     * @param recipient address of the recipient of pool token
     * @param transferAmount amount of pool token to transfer
     */
    function updateUserWithdrawFee(address recipient, uint256 transferAmount)
        external
    {
        require(
            msg.sender == address(swapStorage.lpToken),
            "Only callable by pool token"
        );
        swapStorage.updateUserWithdrawFee(recipient, transferAmount);
    }

    // /**
    //  * @notice Withdraw all admin fees to the contract owner
    //  */
    // function withdrawAdminFees() external onlyOwner {
    //     swapStorage.withdrawAdminFees(owner());
    // }

    // /**
    //  * @notice Update the admin fee. Admin fee takes portion of the swap fee.
    //  * @param newAdminFee new admin fee to be applied on future transactions
    //  */
    // function setAdminFee(uint256 newAdminFee) external onlyOwner {
    //     swapStorage.setAdminFee(newAdminFee);
    // }

    // /**
    //  * @notice Update the swap fee to be applied on swaps
    //  * @param newSwapFee new swap fee to be applied on future transactions
    //  */
    // function setSwapFee(uint256 newSwapFee) external onlyOwner {
    //     swapStorage.setSwapFee(newSwapFee);
    // }

    // /**
    //  * @notice Update the withdraw fee. This fee decays linearly over 4 weeks since
    //  * user's last deposit.
    //  * @param newWithdrawFee new withdraw fee to be applied on future deposits
    //  */
    // function setDefaultWithdrawFee(uint256 newWithdrawFee) external onlyOwner {
    //     swapStorage.setDefaultWithdrawFee(newWithdrawFee);
    // }

    // /**
    //  * @notice Start ramping up or down A parameter towards given futureA and futureTime
    //  * Checks if the change is too rapid, and commits the new A value only when it falls under
    //  * the limit range.
    //  * @param futureA the new A to ramp towards
    //  * @param futureTime timestamp when the new A should be reached
    //  */
    // function rampA(uint256 futureA, uint256 futureTime) external onlyOwner {
    //     swapStorage.rampA(futureA, futureTime);
    // }

    // /**
    //  * @notice Stop ramping A immediately. Reverts if ramp A is already stopped.
    //  */
    // function stopRampA() external onlyOwner {
    //     swapStorage.stopRampA();
    // }
}

File 51 of 72 : ReentrancyGuardUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;
import "../proxy/Initializable.sol";

/**
 * @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 ReentrancyGuardUpgradeable is Initializable {
    // 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;

    function __ReentrancyGuard_init() internal initializer {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal initializer {
        _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;
    }
    uint256[49] private __gap;
}

File 52 of 72 : Initializable.sol
// SPDX-License-Identifier: MIT

// solhint-disable-next-line compiler-version
pragma solidity >=0.4.24 <0.8.0;

import "../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 */
abstract contract Initializable {

    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }

    /// @dev Returns true if and only if the function is running in the constructor
    function _isConstructor() private view returns (bool) {
        return !AddressUpgradeable.isContract(address(this));
    }
}

File 53 of 72 : AddressUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

File 54 of 72 : OwnerPausableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/PausableUpgradeable.sol";

/**
 * @title OwnerPausable
 * @notice An ownable contract allows the owner to pause and unpause the
 * contract without a delay.
 * @dev Only methods using the provided modifiers will be paused.
 */
abstract contract OwnerPausableUpgradeable is
    OwnableUpgradeable,
    PausableUpgradeable
{
    function __OwnerPausable_init() internal initializer {
        __Context_init_unchained();
        __Ownable_init_unchained();
        __Pausable_init_unchained();
    }

    /**
     * @notice Pause the contract. Revert if already paused.
     */
    function pause() external onlyOwner {
        PausableUpgradeable._pause();
    }

    /**
     * @notice Unpause the contract. Revert if already unpaused.
     */
    function unpause() external onlyOwner {
        PausableUpgradeable._unpause();
    }
}

File 55 of 72 : OwnableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/ContextUpgradeable.sol";
import "../proxy/Initializable.sol";
/**
 * @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 OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal initializer {
        __Context_init_unchained();
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal initializer {
        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;
    }
    uint256[49] private __gap;
}

File 56 of 72 : PausableUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./ContextUpgradeable.sol";
import "../proxy/Initializable.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    function __Pausable_init() internal initializer {
        __Context_init_unchained();
        __Pausable_init_unchained();
    }

    function __Pausable_init_unchained() internal initializer {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(paused(), "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
    uint256[49] private __gap;
}

File 57 of 72 : ContextUpgradeable.sol
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;
import "../proxy/Initializable.sol";

/*
 * @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 ContextUpgradeable is Initializable {
    function __Context_init() internal initializer {
        __Context_init_unchained();
    }

    function __Context_init_unchained() internal initializer {
    }
    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;
    }
    uint256[50] private __gap;
}

File 58 of 72 : MockMessenger.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "../interfaces/polygon/messengers/IPolygonFxChild.sol";

import "./BytesLib.sol";

abstract contract MockMessenger {
    using SafeERC20 for IERC20;
    using BytesLib for bytes;

    struct Message {
        address target;
        bytes message;
        address sender;
    }

    Message public nextMessage;
    IERC20 public canonicalToken;

    /**
     * Chain specific params
     */

    // Optimism
    address public xDomainMessageSender;

    // XDai
    address public messageSender;
    bytes32 public messageSourceChainId = 0x000000000000000000000000000000000000000000000000000000000000002a;

    constructor(IERC20 _canonicalToken) public {
        canonicalToken = _canonicalToken;
    }

    function relayNextMessage() public {
        messageSender = nextMessage.sender;
        xDomainMessageSender = nextMessage.sender;

        // Use sender address to signify where the message is coming from 
        bool isFromPolygonL1 = nextMessage.sender == address(1);

        if (isFromPolygonL1) {
            uint256 stateId = 0;
            IPolygonFxChild(nextMessage.target).onStateReceive(stateId, nextMessage.message);
        } else {
            (bool success, bytes memory res) = nextMessage.target.call(nextMessage.message);
            require(success, _getRevertMsgFromRes(res));
        }
    }

    function receiveMessage(
        address _target,
        bytes memory _message,
        address _sender
    )
        public
    {
        nextMessage = Message(
            _target,
            _message,
            _sender
        );
    }

    function _getRevertMsgFromRes(bytes memory _res) internal pure returns (string memory) {
        // If the _res length is less than 68, then the transaction failed silently (without a revert message)
        if (_res.length < 68) return 'BA: Transaction reverted silently';
        bytes memory revertData = _res.slice(4, _res.length - 4); // Remove the selector which is the first 4 bytes
        return abi.decode(revertData, (string)); // All that remains is the revert string
    }
}

File 59 of 72 : IPolygonFxChild.sol
// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

interface IPolygonFxChild {
    function onStateReceive(uint256 stateId, bytes calldata _data) external;
}

File 60 of 72 : BytesLib.sol
// SPDX-License-Identifier: Unlicense
/*
 * @title Solidity Bytes Arrays Utils
 * @author Gonçalo Sá <[email protected]>
 *
 * @dev Bytes tightly packed arrays utility library for ethereum contracts written in Solidity.
 *      The library lets you concatenate, slice and type cast bytes arrays both in memory and storage.
 */
pragma solidity >=0.5.0 <0.7.0;


library BytesLib {
    function concat(
        bytes memory _preBytes,
        bytes memory _postBytes
    )
        internal
        pure
        returns (bytes memory)
    {
        bytes memory tempBytes;

        assembly {
            // Get a location of some free memory and store it in tempBytes as
            // Solidity does for memory variables.
            tempBytes := mload(0x40)

            // Store the length of the first bytes array at the beginning of
            // the memory for tempBytes.
            let length := mload(_preBytes)
            mstore(tempBytes, length)

            // Maintain a memory counter for the current write location in the
            // temp bytes array by adding the 32 bytes for the array length to
            // the starting location.
            let mc := add(tempBytes, 0x20)
            // Stop copying when the memory counter reaches the length of the
            // first bytes array.
            let end := add(mc, length)

            for {
                // Initialize a copy counter to the start of the _preBytes data,
                // 32 bytes into its memory.
                let cc := add(_preBytes, 0x20)
            } lt(mc, end) {
                // Increase both counters by 32 bytes each iteration.
                mc := add(mc, 0x20)
                cc := add(cc, 0x20)
            } {
                // Write the _preBytes data into the tempBytes memory 32 bytes
                // at a time.
                mstore(mc, mload(cc))
            }

            // Add the length of _postBytes to the current length of tempBytes
            // and store it as the new length in the first 32 bytes of the
            // tempBytes memory.
            length := mload(_postBytes)
            mstore(tempBytes, add(length, mload(tempBytes)))

            // Move the memory counter back from a multiple of 0x20 to the
            // actual end of the _preBytes data.
            mc := end
            // Stop copying when the memory counter reaches the new combined
            // length of the arrays.
            end := add(mc, length)

            for {
                let cc := add(_postBytes, 0x20)
            } lt(mc, end) {
                mc := add(mc, 0x20)
                cc := add(cc, 0x20)
            } {
                mstore(mc, mload(cc))
            }

            // Update the free-memory pointer by padding our last write location
            // to 32 bytes: add 31 bytes to the end of tempBytes to move to the
            // next 32 byte block, then round down to the nearest multiple of
            // 32. If the sum of the length of the two arrays is zero then add
            // one before rounding down to leave a blank 32 bytes (the length block with 0).
            mstore(0x40, and(
              add(add(end, iszero(add(length, mload(_preBytes)))), 31),
              not(31) // Round down to the nearest 32 bytes.
            ))
        }

        return tempBytes;
    }

    function concatStorage(bytes storage _preBytes, bytes memory _postBytes) internal {
        assembly {
            // Read the first 32 bytes of _preBytes storage, which is the length
            // of the array. (We don't need to use the offset into the slot
            // because arrays use the entire slot.)
            let fslot := sload(_preBytes_slot)
            // Arrays of 31 bytes or less have an even value in their slot,
            // while longer arrays have an odd value. The actual length is
            // the slot divided by two for odd values, and the lowest order
            // byte divided by two for even values.
            // If the slot is even, bitwise and the slot with 255 and divide by
            // two to get the length. If the slot is odd, bitwise and the slot
            // with -1 and divide by two.
            let slength := div(and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)), 2)
            let mlength := mload(_postBytes)
            let newlength := add(slength, mlength)
            // slength can contain both the length and contents of the array
            // if length < 32 bytes so let's prepare for that
            // v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage
            switch add(lt(slength, 32), lt(newlength, 32))
            case 2 {
                // Since the new array still fits in the slot, we just need to
                // update the contents of the slot.
                // uint256(bytes_storage) = uint256(bytes_storage) + uint256(bytes_memory) + new_length
                sstore(
                    _preBytes_slot,
                    // all the modifications to the slot are inside this
                    // next block
                    add(
                        // we can just add to the slot contents because the
                        // bytes we want to change are the LSBs
                        fslot,
                        add(
                            mul(
                                div(
                                    // load the bytes from memory
                                    mload(add(_postBytes, 0x20)),
                                    // zero all bytes to the right
                                    exp(0x100, sub(32, mlength))
                                ),
                                // and now shift left the number of bytes to
                                // leave space for the length in the slot
                                exp(0x100, sub(32, newlength))
                            ),
                            // increase length by the double of the memory
                            // bytes length
                            mul(mlength, 2)
                        )
                    )
                )
            }
            case 1 {
                // The stored value fits in the slot, but the combined value
                // will exceed it.
                // get the keccak hash to get the contents of the array
                mstore(0x0, _preBytes_slot)
                let sc := add(keccak256(0x0, 0x20), div(slength, 32))

                // save new length
                sstore(_preBytes_slot, add(mul(newlength, 2), 1))

                // The contents of the _postBytes array start 32 bytes into
                // the structure. Our first read should obtain the `submod`
                // bytes that can fit into the unused space in the last word
                // of the stored array. To get this, we read 32 bytes starting
                // from `submod`, so the data we read overlaps with the array
                // contents by `submod` bytes. Masking the lowest-order
                // `submod` bytes allows us to add that value directly to the
                // stored value.

                let submod := sub(32, slength)
                let mc := add(_postBytes, submod)
                let end := add(_postBytes, mlength)
                let mask := sub(exp(0x100, submod), 1)

                sstore(
                    sc,
                    add(
                        and(
                            fslot,
                            0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff00
                        ),
                        and(mload(mc), mask)
                    )
                )

                for {
                    mc := add(mc, 0x20)
                    sc := add(sc, 1)
                } lt(mc, end) {
                    sc := add(sc, 1)
                    mc := add(mc, 0x20)
                } {
                    sstore(sc, mload(mc))
                }

                mask := exp(0x100, sub(mc, end))

                sstore(sc, mul(div(mload(mc), mask), mask))
            }
            default {
                // get the keccak hash to get the contents of the array
                mstore(0x0, _preBytes_slot)
                // Start copying to the last used word of the stored array.
                let sc := add(keccak256(0x0, 0x20), div(slength, 32))

                // save new length
                sstore(_preBytes_slot, add(mul(newlength, 2), 1))

                // Copy over the first `submod` bytes of the new data as in
                // case 1 above.
                let slengthmod := mod(slength, 32)
                let mlengthmod := mod(mlength, 32)
                let submod := sub(32, slengthmod)
                let mc := add(_postBytes, submod)
                let end := add(_postBytes, mlength)
                let mask := sub(exp(0x100, submod), 1)

                sstore(sc, add(sload(sc), and(mload(mc), mask)))

                for {
                    sc := add(sc, 1)
                    mc := add(mc, 0x20)
                } lt(mc, end) {
                    sc := add(sc, 1)
                    mc := add(mc, 0x20)
                } {
                    sstore(sc, mload(mc))
                }

                mask := exp(0x100, sub(mc, end))

                sstore(sc, mul(div(mload(mc), mask), mask))
            }
        }
    }

    function slice(
        bytes memory _bytes,
        uint256 _start,
        uint256 _length
    )
        internal
        pure
        returns (bytes memory)
    {
        require(_length + 31 >= _length, "slice_overflow");
        require(_start + _length >= _start, "slice_overflow");
        require(_bytes.length >= _start + _length, "slice_outOfBounds");

        bytes memory tempBytes;

        assembly {
            switch iszero(_length)
            case 0 {
                // Get a location of some free memory and store it in tempBytes as
                // Solidity does for memory variables.
                tempBytes := mload(0x40)

                // The first word of the slice result is potentially a partial
                // word read from the original array. To read it, we calculate
                // the length of that partial word and start copying that many
                // bytes into the array. The first word we copy will start with
                // data we don't care about, but the last `lengthmod` bytes will
                // land at the beginning of the contents of the new array. When
                // we're done copying, we overwrite the full first word with
                // the actual length of the slice.
                let lengthmod := and(_length, 31)

                // The multiplication in the next line is necessary
                // because when slicing multiples of 32 bytes (lengthmod == 0)
                // the following copy loop was copying the origin's length
                // and then ending prematurely not copying everything it should.
                let mc := add(add(tempBytes, lengthmod), mul(0x20, iszero(lengthmod)))
                let end := add(mc, _length)

                for {
                    // The multiplication in the next line has the same exact purpose
                    // as the one above.
                    let cc := add(add(add(_bytes, lengthmod), mul(0x20, iszero(lengthmod))), _start)
                } lt(mc, end) {
                    mc := add(mc, 0x20)
                    cc := add(cc, 0x20)
                } {
                    mstore(mc, mload(cc))
                }

                mstore(tempBytes, _length)

                //update free-memory pointer
                //allocating the array padded to 32 bytes like the compiler does now
                mstore(0x40, and(add(mc, 31), not(31)))
            }
            //if we want a zero-length slice let's just return a zero-length array
            default {
                tempBytes := mload(0x40)
                //zero out the 32 bytes slice we are about to return
                //we need to do it because Solidity does not garbage collect
                mstore(tempBytes, 0)

                mstore(0x40, add(tempBytes, 0x20))
            }
        }

        return tempBytes;
    }

    function toAddress(bytes memory _bytes, uint256 _start) internal pure returns (address) {
        require(_start + 20 >= _start, "toAddress_overflow");
        require(_bytes.length >= _start + 20, "toAddress_outOfBounds");
        address tempAddress;

        assembly {
            tempAddress := div(mload(add(add(_bytes, 0x20), _start)), 0x1000000000000000000000000)
        }

        return tempAddress;
    }

    function toUint8(bytes memory _bytes, uint256 _start) internal pure returns (uint8) {
        require(_start + 1 >= _start, "toUint8_overflow");
        require(_bytes.length >= _start + 1 , "toUint8_outOfBounds");
        uint8 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x1), _start))
        }

        return tempUint;
    }

    function toUint16(bytes memory _bytes, uint256 _start) internal pure returns (uint16) {
        require(_start + 2 >= _start, "toUint16_overflow");
        require(_bytes.length >= _start + 2, "toUint16_outOfBounds");
        uint16 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x2), _start))
        }

        return tempUint;
    }

    function toUint32(bytes memory _bytes, uint256 _start) internal pure returns (uint32) {
        require(_start + 4 >= _start, "toUint32_overflow");
        require(_bytes.length >= _start + 4, "toUint32_outOfBounds");
        uint32 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x4), _start))
        }

        return tempUint;
    }

    function toUint64(bytes memory _bytes, uint256 _start) internal pure returns (uint64) {
        require(_start + 8 >= _start, "toUint64_overflow");
        require(_bytes.length >= _start + 8, "toUint64_outOfBounds");
        uint64 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x8), _start))
        }

        return tempUint;
    }

    function toUint96(bytes memory _bytes, uint256 _start) internal pure returns (uint96) {
        require(_start + 12 >= _start, "toUint96_overflow");
        require(_bytes.length >= _start + 12, "toUint96_outOfBounds");
        uint96 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0xc), _start))
        }

        return tempUint;
    }

    function toUint128(bytes memory _bytes, uint256 _start) internal pure returns (uint128) {
        require(_start + 16 >= _start, "toUint128_overflow");
        require(_bytes.length >= _start + 16, "toUint128_outOfBounds");
        uint128 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x10), _start))
        }

        return tempUint;
    }

    function toUint256(bytes memory _bytes, uint256 _start) internal pure returns (uint256) {
        require(_start + 32 >= _start, "toUint256_overflow");
        require(_bytes.length >= _start + 32, "toUint256_outOfBounds");
        uint256 tempUint;

        assembly {
            tempUint := mload(add(add(_bytes, 0x20), _start))
        }

        return tempUint;
    }

    function toBytes32(bytes memory _bytes, uint256 _start) internal pure returns (bytes32) {
        require(_start + 32 >= _start, "toBytes32_overflow");
        require(_bytes.length >= _start + 32, "toBytes32_outOfBounds");
        bytes32 tempBytes32;

        assembly {
            tempBytes32 := mload(add(add(_bytes, 0x20), _start))
        }

        return tempBytes32;
    }

    function equal(bytes memory _preBytes, bytes memory _postBytes) internal pure returns (bool) {
        bool success = true;

        assembly {
            let length := mload(_preBytes)

            // if lengths don't match the arrays are not equal
            switch eq(length, mload(_postBytes))
            case 1 {
                // cb is a circuit breaker in the for loop since there's
                //  no said feature for inline assembly loops
                // cb = 1 - don't breaker
                // cb = 0 - break
                let cb := 1

                let mc := add(_preBytes, 0x20)
                let end := add(mc, length)

                for {
                    let cc := add(_postBytes, 0x20)
                // the next line is the loop condition:
                // while(uint256(mc < end) + cb == 2)
                } eq(add(lt(mc, end), cb), 2) {
                    mc := add(mc, 0x20)
                    cc := add(cc, 0x20)
                } {
                    // if any of these checks fails then arrays are not equal
                    if iszero(eq(mload(mc), mload(cc))) {
                        // unsuccess:
                        success := 0
                        cb := 0
                    }
                }
            }
            default {
                // unsuccess:
                success := 0
            }
        }

        return success;
    }

    function equalStorage(
        bytes storage _preBytes,
        bytes memory _postBytes
    )
        internal
        view
        returns (bool)
    {
        bool success = true;

        assembly {
            // we know _preBytes_offset is 0
            let fslot := sload(_preBytes_slot)
            // Decode the length of the stored array like in concatStorage().
            let slength := div(and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)), 2)
            let mlength := mload(_postBytes)

            // if lengths don't match the arrays are not equal
            switch eq(slength, mlength)
            case 1 {
                // slength can contain both the length and contents of the array
                // if length < 32 bytes so let's prepare for that
                // v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage
                if iszero(iszero(slength)) {
                    switch lt(slength, 32)
                    case 1 {
                        // blank the last byte which is the length
                        fslot := mul(div(fslot, 0x100), 0x100)

                        if iszero(eq(fslot, mload(add(_postBytes, 0x20)))) {
                            // unsuccess:
                            success := 0
                        }
                    }
                    default {
                        // cb is a circuit breaker in the for loop since there's
                        //  no said feature for inline assembly loops
                        // cb = 1 - don't breaker
                        // cb = 0 - break
                        let cb := 1

                        // get the keccak hash to get the contents of the array
                        mstore(0x0, _preBytes_slot)
                        let sc := keccak256(0x0, 0x20)

                        let mc := add(_postBytes, 0x20)
                        let end := add(mc, mlength)

                        // the next line is the loop condition:
                        // while(uint256(mc < end) + cb == 2)
                        for {} eq(add(lt(mc, end), cb), 2) {
                            sc := add(sc, 1)
                            mc := add(mc, 0x20)
                        } {
                            if iszero(eq(sload(sc), mload(mc))) {
                                // unsuccess:
                                success := 0
                                cb := 0
                            }
                        }
                    }
                }
            }
            default {
                // unsuccess:
                success := 0
            }
        }

        return success;
    }
}

File 61 of 72 : Mock_L2_Messenger.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "./MockMessenger.sol";
import "./Mock_L1_Messenger.sol";

contract Mock_L2_Messenger is MockMessenger {

    Mock_L1_Messenger public targetMessenger;
    // This should be the PolygonMessengerWrapper
    address public polygonTarget;

    constructor (IERC20 _canonicalToken) public MockMessenger(_canonicalToken) {}

    function setTargetMessenger(address _targetMessenger) public {
        targetMessenger = Mock_L1_Messenger(_targetMessenger);
    }

    function setPolygonTarget(address _polygonTarget) public {
        polygonTarget = _polygonTarget;
    }

    /* ========== Arbitrum ========== */

    function sendTxToL1(
        address _destAddr,
        bytes calldata _calldataForL1
    )
        external
        payable
    {
        targetMessenger.receiveMessage(
            _destAddr,
            _calldataForL1,
            msg.sender
        );
    }


    /* ========== Optimism ========== */

    function sendMessage(
        address _target,
        bytes calldata _message,
        uint32 /* _gasLimit */
    )
        public
    {
        targetMessenger.receiveMessage(
            _target,
            _message,
            msg.sender
        );
    }

    /* ========== xDai ========== */

    function requireToPassMessage(
        address _target,
        bytes calldata _message,
        uint256 /* _gasLimit */
    )
        public
        returns (bytes32)
    {
        targetMessenger.receiveMessage(
            _target,
            _message,
            msg.sender
        );

        return bytes32(0);
    }

    /* ========== Polygon ========== */

    // Polygon L2 to L1 messaging is event-based
}

File 62 of 72 : Mock_L1_Messenger.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "./MockMessenger.sol";
import "./Mock_L2_Messenger.sol";

contract Mock_L1_Messenger is MockMessenger {

    Mock_L2_Messenger public targetMessenger;

    constructor (IERC20 _canonicalToken) public MockMessenger(_canonicalToken) {}

    function setTargetMessenger(address _targetMessenger) public {
        targetMessenger = Mock_L2_Messenger(_targetMessenger);
    }

    /* ========== Arbitrum ========== */

    function createRetryableTicket(
        address _destAddr,
        uint256 /* _arbTxCallValue */,
        uint256 /* _maxSubmissionCost */,
        address /* _submissionRefundAddress */,
        address /* _valueRefundAddress */,
        uint256 /* _maxGas */,
        uint256 /* _gasPriceBid */,
        bytes calldata _data
    )
        external
        payable
        returns (uint256)
    {
        targetMessenger.receiveMessage(
            _destAddr,
            _data,
            msg.sender
        );
    }

    /* ========== Optimism ========== */

    function sendMessage(
        address _target,
        bytes calldata _message,
        uint32 /* _gasLimit */
    )
        public
    {
        targetMessenger.receiveMessage(
            _target,
            _message,
            msg.sender
        );
    }

    /* ========== xDai ========== */

    function requireToPassMessage(
        address _target,
        bytes calldata _message,
        uint256 /* _gasLimit */
    )
        public
        returns (bytes32)
    {
        targetMessenger.receiveMessage(
            _target,
            _message,
            msg.sender
        );

        return bytes32('0');
    }

    /* ========== Polygon ========== */

    function syncState(
        address _fxChild,
        bytes memory _message
    )
        external
    {
        targetMessenger.receiveMessage(
            _fxChild,
            _message,
            address(1)
        );
    }

    function syncStateCanonicalToken(
        address _target,
        bytes memory _message
    )
        public
    {
        targetMessenger.receiveMessage(
            _target,
            _message,
            msg.sender
        );
    }
}

File 63 of 72 : Mock_L1_CanonicalBridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";

import "./Mock_L1_Messenger.sol";

contract Mock_L1_CanonicalBridge {
    using SafeERC20 for IERC20;

    IERC20 public canonicalToken;
    Mock_L1_Messenger public messenger;

    constructor (
        IERC20 _canonicalToken,
        Mock_L1_Messenger _messenger
    )
         public
    {
        canonicalToken = _canonicalToken;
        messenger = _messenger;
    }

    function sendMessage(
        address _target,
        bytes memory _message
    )
        public
    {
        messenger.sendMessage(
            _target,
            _message,
            uint32(0)
        );
    }

    /// @notice Polygon has a different messenger for each token
    function sendTokens(
        address _target,
        address _recipient,
        uint256 _amount,
        bool isPolygon
    )
        public
    {
        bytes memory mintCalldata = abi.encodeWithSignature("mint(address,uint256)", _recipient, _amount);

        canonicalToken.safeTransferFrom(msg.sender, address(this), _amount);

        if (isPolygon) {
            messenger.syncStateCanonicalToken(_target, mintCalldata);
        } else {
            sendMessage(_target, mintCalldata);
        }
    }
}

File 64 of 72 : IWETH.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint value) external returns (bool);
    function withdraw(uint) external;
}

File 65 of 72 : L1_ERC20_Bridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "./L1_Bridge.sol";

/**
 * @dev A L1_Bridge that uses an ERC20 as the canonical token
 */

contract L1_ERC20_Bridge is L1_Bridge {
    using SafeERC20 for IERC20;

    IERC20 public immutable l1CanonicalToken;

    constructor (IERC20 _l1CanonicalToken, address[] memory bonders, address _governance) public L1_Bridge(bonders, _governance) {
        l1CanonicalToken = _l1CanonicalToken;
    }

    /* ========== Override Functions ========== */

    function _transferFromBridge(address recipient, uint256 amount) internal override {
        l1CanonicalToken.safeTransfer(recipient, amount);
    }

    function _transferToBridge(address from, uint256 amount) internal override {
        l1CanonicalToken.safeTransferFrom(from, address(this), amount);
    }
}

File 66 of 72 : L1_Bridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "./Bridge.sol";
import "../interfaces/IMessengerWrapper.sol";

/**
 * @dev L1_Bridge is responsible for the bonding and challenging of TransferRoots. All TransferRoots
 * originate in the L1_Bridge through `bondTransferRoot` and are propagated up to destination L2s.
 */

abstract contract L1_Bridge is Bridge {

    struct TransferBond {
        address bonder;
        uint256 createdAt;
        uint256 totalAmount;
        uint256 challengeStartTime;
        address challenger;
        bool challengeResolved;
    }

    /* ========== State ========== */

    mapping(uint256 => mapping(bytes32 => uint256)) public transferRootCommittedAt;
    mapping(bytes32 => TransferBond) public transferBonds;
    mapping(uint256 => mapping(address => uint256)) public timeSlotToAmountBonded;
    mapping(uint256 => uint256) public chainBalance;

    /* ========== Config State ========== */

    address public governance;
    mapping(uint256 => IMessengerWrapper) public crossDomainMessengerWrappers;
    mapping(uint256 => bool) public isChainIdPaused;
    uint256 public challengePeriod = 1 days;
    uint256 public challengeResolutionPeriod = 10 days;
    uint256 public minTransferRootBondDelay = 15 minutes;
    
    uint256 public constant CHALLENGE_AMOUNT_DIVISOR = 10;
    uint256 public constant TIME_SLOT_SIZE = 4 hours;

    /* ========== Events ========== */

    event TransferSentToL2(
        uint256 indexed chainId,
        address indexed recipient,
        uint256 amount,
        uint256 amountOutMin,
        uint256 deadline,
        address indexed relayer,
        uint256 relayerFee
    );

    event TransferRootBonded (
        bytes32 indexed root,
        uint256 amount
    );

    event TransferRootConfirmed(
        uint256 indexed originChainId,
        uint256 indexed destinationChainId,
        bytes32 indexed rootHash,
        uint256 totalAmount
    );

    event TransferBondChallenged(
        bytes32 indexed transferRootId,
        bytes32 indexed rootHash,
        uint256 originalAmount
    );

    event ChallengeResolved(
        bytes32 indexed transferRootId,
        bytes32 indexed rootHash,
        uint256 originalAmount
    );

    /* ========== Modifiers ========== */

    modifier onlyL2Bridge(uint256 chainId) {
        IMessengerWrapper messengerWrapper = crossDomainMessengerWrappers[chainId];
        messengerWrapper.verifySender(msg.sender, msg.data);
        _;
    }

    constructor (address[] memory bonders, address _governance) public Bridge(bonders) {
        governance = _governance;
    }

    /* ========== Send Functions ========== */

    /**
     * @notice `amountOutMin` and `deadline` should be 0 when no swap is intended at the destination.
     * @notice `amount` is the total amount the user wants to send including the relayer fee
     * @dev Send tokens to a supported layer-2 to mint hToken and optionally swap the hToken in the
     * AMM at the destination.
     * @param chainId The chainId of the destination chain
     * @param recipient The address receiving funds at the destination
     * @param amount The amount being sent
     * @param amountOutMin The minimum amount received after attempting to swap in the destination
     * AMM market. 0 if no swap is intended.
     * @param deadline The deadline for swapping in the destination AMM market. 0 if no
     * swap is intended.
     * @param relayer The address of the relayer at the destination.
     * @param relayerFee The amount distributed to the relayer at the destination. This is subtracted from the `amount`.
     */
    function sendToL2(
        uint256 chainId,
        address recipient,
        uint256 amount,
        uint256 amountOutMin,
        uint256 deadline,
        address relayer,
        uint256 relayerFee
    )
        external
        payable
    {
        IMessengerWrapper messengerWrapper = crossDomainMessengerWrappers[chainId];
        require(messengerWrapper != IMessengerWrapper(0), "L1_BRG: chainId not supported");
        require(isChainIdPaused[chainId] == false, "L1_BRG: Sends to this chainId are paused");
        require(amount > 0, "L1_BRG: Must transfer a non-zero amount");
        require(amount >= relayerFee, "L1_BRG: Relayer fee cannot exceed amount");

        _transferToBridge(msg.sender, amount);

        bytes memory message = abi.encodeWithSignature(
            "distribute(address,uint256,uint256,uint256,address,uint256)",
            recipient,
            amount,
            amountOutMin,
            deadline,
            relayer,
            relayerFee
        );

        chainBalance[chainId] = chainBalance[chainId].add(amount);
        messengerWrapper.sendCrossDomainMessage(message);

        emit TransferSentToL2(
            chainId,
            recipient,
            amount,
            amountOutMin,
            deadline,
            relayer,
            relayerFee
        );
    }

    /* ========== TransferRoot Functions ========== */

    /**
     * @dev Setting a TransferRoot is a two step process.
     * @dev   1. The TransferRoot is bonded with `bondTransferRoot`. Withdrawals can now begin on L1
     * @dev      and recipient L2's
     * @dev   2. The TransferRoot is confirmed after `confirmTransferRoot` is called by the l2 bridge
     * @dev      where the TransferRoot originated.
     */

    /**
     * @dev Used by the Bonder to bond a TransferRoot and propagate it up to destination L2s
     * @param rootHash The Merkle root of the TransferRoot Merkle tree
     * @param destinationChainId The id of the destination chain
     * @param totalAmount The amount destined for the destination chain
     */
    function bondTransferRoot(
        bytes32 rootHash,
        uint256 destinationChainId,
        uint256 totalAmount
    )
        external
        onlyBonder
        requirePositiveBalance
    {
        bytes32 transferRootId = getTransferRootId(rootHash, totalAmount);
        require(transferRootCommittedAt[destinationChainId][transferRootId] == 0, "L1_BRG: TransferRoot has already been confirmed");
        require(transferBonds[transferRootId].createdAt == 0, "L1_BRG: TransferRoot has already been bonded");

        uint256 currentTimeSlot = getTimeSlot(block.timestamp);
        uint256 bondAmount = getBondForTransferAmount(totalAmount);
        timeSlotToAmountBonded[currentTimeSlot][msg.sender] = timeSlotToAmountBonded[currentTimeSlot][msg.sender].add(bondAmount);

        transferBonds[transferRootId] = TransferBond(
            msg.sender,
            block.timestamp,
            totalAmount,
            uint256(0),
            address(0),
            false
        );

        _distributeTransferRoot(rootHash, destinationChainId, totalAmount);

        emit TransferRootBonded(rootHash, totalAmount);
    }

    /**
     * @dev Used by an L2 bridge to confirm a TransferRoot via cross-domain message. Once a TransferRoot
     * has been confirmed, any challenge against that TransferRoot can be resolved as unsuccessful.
     * @param originChainId The id of the origin chain
     * @param rootHash The Merkle root of the TransferRoot Merkle tree
     * @param destinationChainId The id of the destination chain
     * @param totalAmount The amount destined for each destination chain
     * @param rootCommittedAt The block timestamp when the TransferRoot was committed on its origin chain
     */
    function confirmTransferRoot(
        uint256 originChainId,
        bytes32 rootHash,
        uint256 destinationChainId,
        uint256 totalAmount,
        uint256 rootCommittedAt
    )
        external
        onlyL2Bridge(originChainId)
    {
        bytes32 transferRootId = getTransferRootId(rootHash, totalAmount);
        require(transferRootCommittedAt[destinationChainId][transferRootId] == 0, "L1_BRG: TransferRoot already confirmed");
        require(rootCommittedAt > 0, "L1_BRG: rootCommittedAt must be greater than 0");
        transferRootCommittedAt[destinationChainId][transferRootId] = rootCommittedAt;
        chainBalance[originChainId] = chainBalance[originChainId].sub(totalAmount, "L1_BRG: Amount exceeds chainBalance. This indicates a layer-2 failure.");

        // If the TransferRoot was never bonded, distribute the TransferRoot.
        TransferBond storage transferBond = transferBonds[transferRootId];
        if (transferBond.createdAt == 0) {
            _distributeTransferRoot(rootHash, destinationChainId, totalAmount);
        }

        emit TransferRootConfirmed(originChainId, destinationChainId, rootHash, totalAmount);
    }

    function _distributeTransferRoot(
        bytes32 rootHash,
        uint256 chainId,
        uint256 totalAmount
    )
        internal
    {
        // Set TransferRoot on recipient Bridge
        if (chainId == getChainId()) {
            // Set L1 TransferRoot
            _setTransferRoot(rootHash, totalAmount);
        } else {
            chainBalance[chainId] = chainBalance[chainId].add(totalAmount);

            IMessengerWrapper messengerWrapper = crossDomainMessengerWrappers[chainId];
            require(messengerWrapper != IMessengerWrapper(0), "L1_BRG: chainId not supported");

            // Set L2 TransferRoot
            bytes memory setTransferRootMessage = abi.encodeWithSignature(
                "setTransferRoot(bytes32,uint256)",
                rootHash,
                totalAmount
            );
            messengerWrapper.sendCrossDomainMessage(setTransferRootMessage);
        }
    }

    /* ========== External TransferRoot Challenges ========== */

    /**
     * @dev Challenge a TransferRoot believed to be fraudulent
     * @param rootHash The Merkle root of the TransferRoot Merkle tree
     * @param originalAmount The total amount bonded for this TransferRoot
     * @param destinationChainId The id of the destination chain
     */
    function challengeTransferBond(bytes32 rootHash, uint256 originalAmount, uint256 destinationChainId) external payable {
        bytes32 transferRootId = getTransferRootId(rootHash, originalAmount);
        TransferBond storage transferBond = transferBonds[transferRootId];

        require(transferRootCommittedAt[destinationChainId][transferRootId] == 0, "L1_BRG: TransferRoot has already been confirmed");
        require(transferBond.createdAt != 0, "L1_BRG: TransferRoot has not been bonded");
        uint256 challengePeriodEnd = transferBond.createdAt.add(challengePeriod);
        require(challengePeriodEnd >= block.timestamp, "L1_BRG: TransferRoot cannot be challenged after challenge period");
        require(transferBond.challengeStartTime == 0, "L1_BRG: TransferRoot already challenged");

        transferBond.challengeStartTime = block.timestamp;
        transferBond.challenger = msg.sender;

        // Move amount from timeSlotToAmountBonded to debit
        uint256 timeSlot = getTimeSlot(transferBond.createdAt);
        uint256 bondAmount = getBondForTransferAmount(originalAmount);
        address bonder = transferBond.bonder;
        timeSlotToAmountBonded[timeSlot][bonder] = timeSlotToAmountBonded[timeSlot][bonder].sub(bondAmount);

        _addDebit(transferBond.bonder, bondAmount);

        // Get stake for challenge
        uint256 challengeStakeAmount = getChallengeAmountForTransferAmount(originalAmount);
        _transferToBridge(msg.sender, challengeStakeAmount);

        emit TransferBondChallenged(transferRootId, rootHash, originalAmount);
    }

    /**
     * @dev Resolve a challenge after the `challengeResolutionPeriod` has passed
     * @param rootHash The Merkle root of the TransferRoot Merkle tree
     * @param originalAmount The total amount originally bonded for this TransferRoot
     * @param destinationChainId The id of the destination chain
     */
    function resolveChallenge(bytes32 rootHash, uint256 originalAmount, uint256 destinationChainId) external {
        bytes32 transferRootId = getTransferRootId(rootHash, originalAmount);
        TransferBond storage transferBond = transferBonds[transferRootId];

        require(transferBond.challengeStartTime != 0, "L1_BRG: TransferRoot has not been challenged");
        require(block.timestamp > transferBond.challengeStartTime.add(challengeResolutionPeriod), "L1_BRG: Challenge period has not ended");
        require(transferBond.challengeResolved == false, "L1_BRG: TransferRoot already resolved");
        transferBond.challengeResolved = true;

        uint256 challengeStakeAmount = getChallengeAmountForTransferAmount(originalAmount);

        if (transferRootCommittedAt[destinationChainId][transferRootId] > 0) {
            // Invalid challenge

            if (transferBond.createdAt > transferRootCommittedAt[destinationChainId][transferRootId].add(minTransferRootBondDelay)) {
                // Credit the bonder back with the bond amount plus the challenger's stake
                _addCredit(transferBond.bonder, getBondForTransferAmount(originalAmount).add(challengeStakeAmount));
            } else {
                // If the TransferRoot was bonded before it was committed, the challenger and Bonder
                // get their stake back. This discourages Bonders from tricking challengers into
                // challenging a valid TransferRoots that haven't yet been committed. It also ensures
                // that Bonders are not punished if a TransferRoot is bonded too soon in error.

                // Return the challenger's stake
                _addCredit(transferBond.challenger, challengeStakeAmount);
                // Credit the bonder back with the bond amount
                _addCredit(transferBond.bonder, getBondForTransferAmount(originalAmount));
            }
        } else {
            // Valid challenge
            // Burn 25% of the challengers stake
            _transferFromBridge(address(0xdead), challengeStakeAmount.mul(1).div(4));
            // Reward challenger with the remaining 75% of their stake plus 100% of the Bonder's stake
            _addCredit(transferBond.challenger, challengeStakeAmount.mul(7).div(4));
        }

        emit ChallengeResolved(transferRootId, rootHash, originalAmount);
    }

    /* ========== Override Functions ========== */

    function _additionalDebit(address bonder) internal view override returns (uint256) {
        uint256 currentTimeSlot = getTimeSlot(block.timestamp);
        uint256 bonded = 0;

        uint256 numTimeSlots = challengePeriod / TIME_SLOT_SIZE;
        for (uint256 i = 0; i < numTimeSlots; i++) {
            bonded = bonded.add(timeSlotToAmountBonded[currentTimeSlot - i][bonder]);
        }

        return bonded;
    }

    function _requireIsGovernance() internal override {
        require(governance == msg.sender, "L1_BRG: Caller is not the owner");
    }

    /* ========== External Config Management Setters ========== */

    function setGovernance(address _newGovernance) external onlyGovernance {
        require(_newGovernance != address(0), "L1_BRG: _newGovernance cannot be address(0)");
        governance = _newGovernance;
    }

    function setCrossDomainMessengerWrapper(uint256 chainId, IMessengerWrapper _crossDomainMessengerWrapper) external onlyGovernance {
        crossDomainMessengerWrappers[chainId] = _crossDomainMessengerWrapper;
    }

    function setChainIdDepositsPaused(uint256 chainId, bool isPaused) external onlyGovernance {
        isChainIdPaused[chainId] = isPaused;
    }

    function setChallengePeriod(uint256 _challengePeriod) external onlyGovernance {
        require(_challengePeriod % TIME_SLOT_SIZE == 0, "L1_BRG: challengePeriod must be divisible by TIME_SLOT_SIZE");

        challengePeriod = _challengePeriod;
    }

    function setChallengeResolutionPeriod(uint256 _challengeResolutionPeriod) external onlyGovernance {
        challengeResolutionPeriod = _challengeResolutionPeriod;
    }

    function setMinTransferRootBondDelay(uint256 _minTransferRootBondDelay) external onlyGovernance {
        minTransferRootBondDelay = _minTransferRootBondDelay;
    }

    /* ========== Public Getters ========== */

    function getBondForTransferAmount(uint256 amount) public pure returns (uint256) {
        // Bond covers amount plus a bounty to pay a potential challenger
        return amount.add(getChallengeAmountForTransferAmount(amount));
    }

    function getChallengeAmountForTransferAmount(uint256 amount) public pure returns (uint256) {
        // Bond covers amount plus a bounty to pay a potential challenger
        return amount.div(CHALLENGE_AMOUNT_DIVISOR);
    }

    function getTimeSlot(uint256 time) public pure returns (uint256) {
        return time / TIME_SLOT_SIZE;
    }
}

File 67 of 72 : Mock_L1_ERC20_Bridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/L1_ERC20_Bridge.sol";

contract Mock_L1_ERC20_Bridge is L1_ERC20_Bridge {

    constructor (IERC20 _canonicalToken, address[] memory _bonders, address _governance) public L1_ERC20_Bridge(_canonicalToken, _bonders, _governance) {}

    function getChainId() public override view returns (uint256) {
        return 1;
    }
}

File 68 of 72 : L1_ETH_Bridge.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "./L1_Bridge.sol";

/**
 * @dev A L1_Bridge that uses an ETH as the canonical token
 */

contract L1_ETH_Bridge is L1_Bridge {
    constructor (address[] memory bonders, address _governance) public L1_Bridge(bonders, _governance) {}

    /* ========== Override Functions ========== */

    function _transferFromBridge(address recipient, uint256 amount) internal override {
        (bool success, ) = recipient.call{value: amount}(new bytes(0));
        require(success, 'L1_ETH_BRG: ETH transfer failed');
    }

    function _transferToBridge(address /*from*/, uint256 amount) internal override {
        require(msg.value == amount, "L1_ETH_BRG: Value does not match amount");
    }
}

File 69 of 72 : Mock_L1_ETH_Bridge.sol
// SPDX-License-Identifier: UNLICENSED

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../bridges/L1_ETH_Bridge.sol";

contract Mock_L1_ETH_Bridge is L1_ETH_Bridge {

    constructor (address[] memory _bonders, address _governance) public L1_ETH_Bridge(_bonders, _governance) {}

    function getChainId() public override view returns (uint256) {
        return 1;
    }
}

File 70 of 72 : L2_PolygonBridge.sol
// SPDX-License-Identifier: MIT
// @unsupported: ovm

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "./L2_Bridge.sol";
import "../interfaces/polygon/messengers/I_L2_PolygonMessengerProxy.sol";

/**
 * @dev An L2_Bridge for Polygon - https://docs.matic.network/docs
 */

contract L2_PolygonBridge is L2_Bridge {
    I_L2_PolygonMessengerProxy public messengerProxy;

    event L1_BridgeMessage(bytes data);

    constructor (
        I_L2_PolygonMessengerProxy _messengerProxy,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory activeChainIds,
        address[] memory bonders
    )
        public
        L2_Bridge(
            l1Governance,
            hToken,
            l1BridgeAddress,
            activeChainIds,
            bonders
        )
    {
        messengerProxy = _messengerProxy;
    }

    function _sendCrossDomainMessage(bytes memory message) internal override {
        messengerProxy.sendCrossDomainMessage(message);
    }

    function _verifySender(address expectedSender) internal override {
        require(msg.sender == address(messengerProxy), "L2_PLGN_BRG: Caller is not the expected sender");
        // Verify that cross-domain sender is expectedSender
        require(messengerProxy.xDomainMessageSender() == expectedSender, "L2_PLGN_BRG: Invalid cross-domain sender");
    }

    /**
     * @dev Allows the L1 Bridge to set the messengerProxy proxy
     * @param _messengerProxy The new messengerProxy address
     */
    function setMessengerProxy(I_L2_PolygonMessengerProxy _messengerProxy) external onlyGovernance {
        messengerProxy = _messengerProxy;
    }
}

File 71 of 72 : I_L2_PolygonMessengerProxy.sol
// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

interface I_L2_PolygonMessengerProxy {
    function sendCrossDomainMessage(bytes memory _calldata) external;
    function xDomainMessageSender() external view returns (address);
    function processMessageFromRoot(
        bytes calldata message
    ) external;
}

File 72 of 72 : Mock_L2_PolygonBridge.sol
// SPDX-License-Identifier: UNLICENSED
// @unsupported: ovm

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import "../interfaces/polygon/messengers/I_L2_PolygonMessengerProxy.sol";
import "../bridges/L2_PolygonBridge.sol";

contract Mock_L2_PolygonBridge is L2_PolygonBridge {
    uint256 private chainId;

    constructor (
        uint256 _chainId,
        I_L2_PolygonMessengerProxy messenger,
        address l1Governance,
        HopBridgeToken hToken,
        address l1BridgeAddress,
        uint256[] memory supportedChainIds,
        address[] memory bonders
    )
        public
        L2_PolygonBridge(
            messenger,
            l1Governance,
            hToken,
            l1BridgeAddress,
            supportedChainIds,
            bonders
        )
    {
        chainId = _chainId;
    }

    function getChainId() public override view returns (uint256) {
        return chainId;
    }
}

Settings
{
  "optimizer": {
    "enabled": true,
    "runs": 1
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "abi"
      ]
    }
  },
  "libraries": {}
}

Contract Security Audit

Contract ABI

[{"inputs":[{"internalType":"contract L2_Bridge","name":"_bridge","type":"address"},{"internalType":"contract IERC20","name":"_l2CanonicalToken","type":"address"},{"internalType":"bool","name":"_l2CanonicalTokenIsEth","type":"bool"},{"internalType":"contract IERC20","name":"_hToken","type":"address"},{"internalType":"contract Swap","name":"_exchangeAddress","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"attemptSwap","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"bridge","outputs":[{"internalType":"contract L2_Bridge","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"exchangeAddress","outputs":[{"internalType":"contract Swap","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"hToken","outputs":[{"internalType":"contract IERC20","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"l2CanonicalToken","outputs":[{"internalType":"contract IERC20","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"l2CanonicalTokenIsEth","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"chainId","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"},{"internalType":"uint256","name":"bonderFee","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint256","name":"destinationAmountOutMin","type":"uint256"},{"internalType":"uint256","name":"destinationDeadline","type":"uint256"}],"name":"swapAndSend","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]

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Deployed Bytecode

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Constructor Arguments (ABI-Encoded and is the last bytes of the Contract Creation Code above)

0000000000000000000000007191061d5d4c60f598214cc6913502184baddf18000000000000000000000000da10009cbd5d07dd0cecc66161fc93d7c9000da1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000056900d66d74cb14e3c86895789901c9135c95b16000000000000000000000000f181ed90d6cfac84b8073fdea6d34aa744b41810

-----Decoded View---------------
Arg [0] : _bridge (address): 0x7191061D5d4C60f598214cC6913502184BAddf18
Arg [1] : _l2CanonicalToken (address): 0xDA10009cBd5D07dd0CeCc66161FC93D7c9000da1
Arg [2] : _l2CanonicalTokenIsEth (bool): False
Arg [3] : _hToken (address): 0x56900d66D74Cb14E3c86895789901C9135c95b16
Arg [4] : _exchangeAddress (address): 0xF181eD90D6CfaC84B8073FdEA6D34Aa744B41810

-----Encoded View---------------
5 Constructor Arguments found :
Arg [0] : 0000000000000000000000007191061d5d4c60f598214cc6913502184baddf18
Arg [1] : 000000000000000000000000da10009cbd5d07dd0cecc66161fc93d7c9000da1
Arg [2] : 0000000000000000000000000000000000000000000000000000000000000000
Arg [3] : 00000000000000000000000056900d66d74cb14e3c86895789901c9135c95b16
Arg [4] : 000000000000000000000000f181ed90d6cfac84b8073fdea6d34aa744b41810


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A contract address hosts a smart contract, which is a set of code stored on the blockchain that runs when predetermined conditions are met. Learn more about addresses in our Knowledge Base.