// File: contracts/common/Proxy/IERCProxy.sol

pragma solidity 0.6.6;

interface IERCProxy {
    function proxyType() external pure returns (uint256 proxyTypeId);

    function implementation() external view returns (address codeAddr);
}

// File: contracts/common/Proxy/Proxy.sol

pragma solidity 0.6.6;


abstract contract Proxy is IERCProxy {
    function delegatedFwd(address _dst, bytes memory _calldata) internal {
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let result := delegatecall(
                sub(gas(), 10000),
                _dst,
                add(_calldata, 0x20),
                mload(_calldata),
                0,
                0
            )
            let size := returndatasize()

            let ptr := mload(0x40)
            returndatacopy(ptr, 0, size)

            // revert instead of invalid() bc if the underlying call failed with invalid() it already wasted gas.
            // if the call returned error data, forward it
            switch result
                case 0 {
                    revert(ptr, size)
                }
                default {
                    return(ptr, size)
                }
        }
    }

    function proxyType() external virtual override pure returns (uint256 proxyTypeId) {
        // Upgradeable proxy
        proxyTypeId = 2;
    }

    function implementation() external virtual override view returns (address);
}

// File: contracts/common/Proxy/UpgradableProxy.sol

pragma solidity 0.6.6;


contract UpgradableProxy is Proxy {
    event ProxyUpdated(address indexed _new, address indexed _old);
    event ProxyOwnerUpdate(address _new, address _old);

    bytes32 constant IMPLEMENTATION_SLOT = keccak256("matic.network.proxy.implementation");
    bytes32 constant OWNER_SLOT = keccak256("matic.network.proxy.owner");

    constructor(address _proxyTo) public {
        setProxyOwner(msg.sender);
        setImplementation(_proxyTo);
    }

    fallback() external payable {
        delegatedFwd(loadImplementation(), msg.data);
    }

    receive() external payable {
        delegatedFwd(loadImplementation(), msg.data);
    }

    modifier onlyProxyOwner() {
        require(loadProxyOwner() == msg.sender, "NOT_OWNER");
        _;
    }

    function proxyOwner() external view returns(address) {
        return loadProxyOwner();
    }

    function loadProxyOwner() internal view returns(address) {
        address _owner;
        bytes32 position = OWNER_SLOT;
        assembly {
            _owner := sload(position)
        }
        return _owner;
    }

    function implementation() external override view returns (address) {
        return loadImplementation();
    }

    function loadImplementation() internal view returns(address) {
        address _impl;
        bytes32 position = IMPLEMENTATION_SLOT;
        assembly {
            _impl := sload(position)
        }
        return _impl;
    }

    function transferProxyOwnership(address newOwner) public onlyProxyOwner {
        require(newOwner != address(0), "ZERO_ADDRESS");
        emit ProxyOwnerUpdate(newOwner, loadProxyOwner());
        setProxyOwner(newOwner);
    }

    function setProxyOwner(address newOwner) private {
        bytes32 position = OWNER_SLOT;
        assembly {
            sstore(position, newOwner)
        }
    }

    function updateImplementation(address _newProxyTo) public onlyProxyOwner {
        require(_newProxyTo != address(0x0), "INVALID_PROXY_ADDRESS");
        require(isContract(_newProxyTo), "DESTINATION_ADDRESS_IS_NOT_A_CONTRACT");

        emit ProxyUpdated(_newProxyTo, loadImplementation());
        
        setImplementation(_newProxyTo);
    }

    function updateAndCall(address _newProxyTo, bytes memory data) payable public onlyProxyOwner {
        updateImplementation(_newProxyTo);

        (bool success, bytes memory returnData) = address(this).call{value: msg.value}(data);
        require(success, string(returnData));
    }

    function setImplementation(address _newProxyTo) private {
        bytes32 position = IMPLEMENTATION_SLOT;
        assembly {
            sstore(position, _newProxyTo)
        }
    }
    
    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly {
            size := extcodesize(_target)
        }
        return size > 0;
    }
}

// File: contracts/root/RootChainManager/RootChainManagerProxy.sol

pragma solidity 0.6.6;


contract RootChainManagerProxy is UpgradableProxy {
    constructor(address _proxyTo)
        public
        UpgradableProxy(_proxyTo)
    {}
}

// File: contracts/common/Proxy/IERCProxy.sol

pragma solidity 0.6.6;

interface IERCProxy {
    function proxyType() external pure returns (uint256 proxyTypeId);

    function implementation() external view returns (address codeAddr);
}

// File: contracts/common/Proxy/Proxy.sol

pragma solidity 0.6.6;


abstract contract Proxy is IERCProxy {
    function delegatedFwd(address _dst, bytes memory _calldata) internal {
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let result := delegatecall(
                sub(gas(), 10000),
                _dst,
                add(_calldata, 0x20),
                mload(_calldata),
                0,
                0
            )
            let size := returndatasize()

            let ptr := mload(0x40)
            returndatacopy(ptr, 0, size)

            // revert instead of invalid() bc if the underlying call failed with invalid() it already wasted gas.
            // if the call returned error data, forward it
            switch result
                case 0 {
                    revert(ptr, size)
                }
                default {
                    return(ptr, size)
                }
        }
    }

    function proxyType() external virtual override pure returns (uint256 proxyTypeId) {
        // Upgradeable proxy
        proxyTypeId = 2;
    }

    function implementation() external virtual override view returns (address);
}

// File: contracts/common/Proxy/UpgradableProxy.sol

pragma solidity 0.6.6;


contract UpgradableProxy is Proxy {
    event ProxyUpdated(address indexed _new, address indexed _old);
    event ProxyOwnerUpdate(address _new, address _old);

    bytes32 constant IMPLEMENTATION_SLOT = keccak256("matic.network.proxy.implementation");
    bytes32 constant OWNER_SLOT = keccak256("matic.network.proxy.owner");

    constructor(address _proxyTo) public {
        setProxyOwner(msg.sender);
        setImplementation(_proxyTo);
    }

    fallback() external payable {
        delegatedFwd(loadImplementation(), msg.data);
    }

    receive() external payable {
        delegatedFwd(loadImplementation(), msg.data);
    }

    modifier onlyProxyOwner() {
        require(loadProxyOwner() == msg.sender, "NOT_OWNER");
        _;
    }

    function proxyOwner() external view returns(address) {
        return loadProxyOwner();
    }

    function loadProxyOwner() internal view returns(address) {
        address _owner;
        bytes32 position = OWNER_SLOT;
        assembly {
            _owner := sload(position)
        }
        return _owner;
    }

    function implementation() external override view returns (address) {
        return loadImplementation();
    }

    function loadImplementation() internal view returns(address) {
        address _impl;
        bytes32 position = IMPLEMENTATION_SLOT;
        assembly {
            _impl := sload(position)
        }
        return _impl;
    }

    function transferProxyOwnership(address newOwner) public onlyProxyOwner {
        require(newOwner != address(0), "ZERO_ADDRESS");
        emit ProxyOwnerUpdate(newOwner, loadProxyOwner());
        setProxyOwner(newOwner);
    }

    function setProxyOwner(address newOwner) private {
        bytes32 position = OWNER_SLOT;
        assembly {
            sstore(position, newOwner)
        }
    }

    function updateImplementation(address _newProxyTo) public onlyProxyOwner {
        require(_newProxyTo != address(0x0), "INVALID_PROXY_ADDRESS");
        require(isContract(_newProxyTo), "DESTINATION_ADDRESS_IS_NOT_A_CONTRACT");

        emit ProxyUpdated(_newProxyTo, loadImplementation());
        
        setImplementation(_newProxyTo);
    }

    function updateAndCall(address _newProxyTo, bytes memory data) payable public onlyProxyOwner {
        updateImplementation(_newProxyTo);

        (bool success, bytes memory returnData) = address(this).call{value: msg.value}(data);
        require(success, string(returnData));
    }

    function setImplementation(address _newProxyTo) private {
        bytes32 position = IMPLEMENTATION_SLOT;
        assembly {
            sstore(position, _newProxyTo)
        }
    }
    
    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly {
            size := extcodesize(_target)
        }
        return size > 0;
    }
}

// File: contracts/root/TokenPredicates/ERC20PredicateProxy.sol

pragma solidity 0.6.6;


contract ERC20PredicateProxy is UpgradableProxy {
    constructor(address _proxyTo)
        public
        UpgradableProxy(_proxyTo)
    {}
}

// SPDX-License-Identifier: AGPL-3.0

// File contracts/dependencies/open-zeppelin/Context.sol

pragma solidity 0.7.5;

/*
 * @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 contracts/dependencies/open-zeppelin/IERC20.sol

pragma solidity 0.7.5;

/**
 * @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 contracts/dependencies/open-zeppelin/SafeMath.sol

pragma solidity 0.7.5;

/**
 * @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, 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) {
    return sub(a, b, 'SafeMath: subtraction overflow');
  }

  /**
   * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
   * overflow (when the result is negative).
   *
   * 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);
    uint256 c = a - b;

    return c;
  }

  /**
   * @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) {
    // 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 0;
    }

    uint256 c = a * b;
    require(c / a == b, 'SafeMath: multiplication overflow');

    return c;
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts 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) {
    return div(a, b, 'SafeMath: division by zero');
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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,
    string memory errorMessage
  ) internal pure returns (uint256) {
    // Solidity only automatically asserts when dividing by 0
    require(b > 0, errorMessage);
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold

    return c;
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * Reverts 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) {
    return mod(a, b, 'SafeMath: modulo by zero');
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * Reverts with custom message 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,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b != 0, errorMessage);
    return a % b;
  }
}


// File contracts/dependencies/open-zeppelin/Address.sol

pragma solidity 0.7.5;

/**
 * @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) {
    // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
    // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
    // for accounts without code, i.e. `keccak256('')`
    bytes32 codehash;
    bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
    // solhint-disable-next-line no-inline-assembly
    assembly {
      codehash := extcodehash(account)
    }
    return (codehash != accountHash && codehash != 0x0);
  }

  /**
   * @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');
  }
}


// File contracts/dependencies/open-zeppelin/ERC20.sol

pragma solidity ^0.7.5;




/**
 * @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;
    using Address for address;

    mapping (address => uint256) private _balances;

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

    uint256 private _totalSupply;

    string internal _name;
    string internal _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() virtual public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() virtual public view 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() virtual public view returns (uint8) {
        return _decimals;
    }

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

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view 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 is 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 {
        _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 contracts/dependencies/open-zeppelin/Ownable.sol

pragma solidity 0.7.5;

/**
 * @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.
 */
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() {
    address msgSender = _msgSender();
    _owner = msgSender;
    emit OwnershipTransferred(address(0), msgSender);
  }

  /**
   * @dev Returns the address of the current owner.
   */
  function owner() public view 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 contracts/interfaces/IGovernancePowerDelegationERC20.sol

pragma solidity 0.7.5;

interface IGovernancePowerDelegationERC20 {

  enum DelegationType {
    VOTING_POWER,
    PROPOSITION_POWER
  }

  /**
   * @dev Emitted when a user delegates governance power to another user.
   *
   * @param  delegator       The delegator.
   * @param  delegatee       The delegatee.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   */
  event DelegateChanged(
    address indexed delegator,
    address indexed delegatee,
    DelegationType delegationType
  );

  /**
   * @dev Emitted when an action changes the delegated power of a user.
   *
   * @param  user            The user whose delegated power has changed.
   * @param  amount          The new amount of delegated power for the user.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   */
  event DelegatedPowerChanged(address indexed user, uint256 amount, DelegationType delegationType);

  /**
   * @dev Delegates a specific governance power to a delegatee.
   *
   * @param  delegatee       The address to delegate power to.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   */
  function delegateByType(address delegatee, DelegationType delegationType) external virtual;

  /**
   * @dev Delegates all governance powers to a delegatee.
   *
   * @param  delegatee  The user to which the power will be delegated.
   */
  function delegate(address delegatee) external virtual;

  /**
   * @dev Returns the delegatee of an user.
   *
   * @param  delegator       The address of the delegator.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   */
  function getDelegateeByType(address delegator, DelegationType delegationType)
    external
    view
    virtual
    returns (address);

  /**
   * @dev Returns the current delegated power of a user. The current power is the power delegated
   *  at the time of the last snapshot.
   *
   * @param  user            The user whose power to query.
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function getPowerCurrent(address user, DelegationType delegationType)
    external
    view
    virtual
    returns (uint256);

  /**
   * @dev Returns the delegated power of a user at a certain block.
   *
   * @param  user            The user whose power to query.
   * @param  blockNumber     The block number at which to get the user's power.
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function getPowerAtBlock(
    address user,
    uint256 blockNumber,
    DelegationType delegationType
  )
    external
    view
    virtual
    returns (uint256);
}


// File contracts/governance/token/GovernancePowerDelegationERC20Mixin.sol

pragma solidity 0.7.5;



/**
 * @title GovernancePowerDelegationERC20Mixin
 * @author dYdX
 *
 * @dev Provides support for two types of governance powers, both endowed by the governance
 *  token, and separately delegatable. Provides functions for delegation and for querying a user's
 *  power at a certain block number.
 */
abstract contract GovernancePowerDelegationERC20Mixin is
  ERC20,
  IGovernancePowerDelegationERC20
{
  using SafeMath for uint256;

  // ============ Constants ============

  /// @notice EIP-712 typehash for delegation by signature of a specific governance power type.
  bytes32 public constant DELEGATE_BY_TYPE_TYPEHASH = keccak256(
    'DelegateByType(address delegatee,uint256 type,uint256 nonce,uint256 expiry)'
  );

  /// @notice EIP-712 typehash for delegation by signature of all governance powers.
  bytes32 public constant DELEGATE_TYPEHASH = keccak256(
    'Delegate(address delegatee,uint256 nonce,uint256 expiry)'
  );

  // ============ Structs ============

  /// @dev Snapshot of a value on a specific block, used to track voting power for proposals.
  struct Snapshot {
    uint128 blockNumber;
    uint128 value;
  }

  // ============ External Functions ============

  /**
   * @notice Delegates a specific governance power to a delegatee.
   *
   * @param  delegatee       The address to delegate power to.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   */
  function delegateByType(
    address delegatee,
    DelegationType delegationType
  )
    external
    override
  {
    _delegateByType(msg.sender, delegatee, delegationType);
  }

  /**
   * @notice Delegates all governance powers to a delegatee.
   *
   * @param  delegatee  The address to delegate power to.
   */
  function delegate(
    address delegatee
  )
    external
    override
  {
    _delegateByType(msg.sender, delegatee, DelegationType.VOTING_POWER);
    _delegateByType(msg.sender, delegatee, DelegationType.PROPOSITION_POWER);
  }

  /**
   * @notice Returns the delegatee of a user.
   *
   * @param  delegator       The address of the delegator.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   */
  function getDelegateeByType(
    address delegator,
    DelegationType delegationType
  )
    external
    override
    view
    returns (address)
  {
    (, , mapping(address => address) storage delegates) = _getDelegationDataByType(delegationType);

    return _getDelegatee(delegator, delegates);
  }

  /**
   * @notice Returns the current power of a user. The current power is the power delegated
   *  at the time of the last snapshot.
   *
   * @param  user            The user whose power to query.
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function getPowerCurrent(
    address user,
    DelegationType delegationType
  )
    external
    override
    view
    returns (uint256)
  {
    (
      mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
      mapping(address => uint256) storage snapshotsCounts,
      // delegates
    ) = _getDelegationDataByType(delegationType);

    return _searchByBlockNumber(snapshots, snapshotsCounts, user, block.number);
  }

  /**
   * @notice Returns the power of a user at a certain block.
   *
   * @param  user            The user whose power to query.
   * @param  blockNumber     The block number at which to get the user's power.
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function getPowerAtBlock(
    address user,
    uint256 blockNumber,
    DelegationType delegationType
  )
    external
    override
    view
    returns (uint256)
  {
    (
      mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
      mapping(address => uint256) storage snapshotsCounts,
      // delegates
    ) = _getDelegationDataByType(delegationType);

    return _searchByBlockNumber(snapshots, snapshotsCounts, user, blockNumber);
  }

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

  /**
   * @dev Delegates one specific power to a delegatee.
   *
   * @param  delegator       The user whose power to delegate.
   * @param  delegatee       The address to delegate power to.
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function _delegateByType(
    address delegator,
    address delegatee,
    DelegationType delegationType
  )
    internal
  {
    require(
      delegatee != address(0),
      'INVALID_DELEGATEE'
    );

    (, , mapping(address => address) storage delegates) = _getDelegationDataByType(delegationType);

    uint256 delegatorBalance = balanceOf(delegator);

    address previousDelegatee = _getDelegatee(delegator, delegates);

    delegates[delegator] = delegatee;

    _moveDelegatesByType(previousDelegatee, delegatee, delegatorBalance, delegationType);
    emit DelegateChanged(delegator, delegatee, delegationType);
  }

  /**
   * @dev Moves power from one user to another.
   *
   * @param  from            The user from which delegated power is moved.
   * @param  to              The user that will receive the delegated power.
   * @param  amount          The amount of power to be moved.
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function _moveDelegatesByType(
    address from,
    address to,
    uint256 amount,
    DelegationType delegationType
  )
    internal
  {
    if (from == to) {
      return;
    }

    (
      mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
      mapping(address => uint256) storage snapshotsCounts,
      // delegates
    ) = _getDelegationDataByType(delegationType);

    if (from != address(0)) {
      uint256 previous = 0;
      uint256 fromSnapshotsCount = snapshotsCounts[from];

      if (fromSnapshotsCount != 0) {
        previous = snapshots[from][fromSnapshotsCount - 1].value;
      } else {
        previous = balanceOf(from);
      }

      uint256 newAmount = previous.sub(amount);
      _writeSnapshot(
        snapshots,
        snapshotsCounts,
        from,
        uint128(newAmount)
      );

      emit DelegatedPowerChanged(from, newAmount, delegationType);
    }

    if (to != address(0)) {
      uint256 previous = 0;
      uint256 toSnapshotsCount = snapshotsCounts[to];
      if (toSnapshotsCount != 0) {
        previous = snapshots[to][toSnapshotsCount - 1].value;
      } else {
        previous = balanceOf(to);
      }

      uint256 newAmount = previous.add(amount);
      _writeSnapshot(
        snapshots,
        snapshotsCounts,
        to,
        uint128(newAmount)
      );

      emit DelegatedPowerChanged(to, newAmount, delegationType);
    }
  }

  /**
   * @dev Searches for a balance snapshot by block number using binary search.
   *
   * @param  snapshots        The mapping of snapshots by user.
   * @param  snapshotsCounts  The mapping of the number of snapshots by user.
   * @param  user             The user for which the snapshot is being searched.
   * @param  blockNumber      The block number being searched.
   */
  function _searchByBlockNumber(
    mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
    mapping(address => uint256) storage snapshotsCounts,
    address user,
    uint256 blockNumber
  )
    internal
    view
    returns (uint256)
  {
    require(
      blockNumber <= block.number,
      'INVALID_BLOCK_NUMBER'
    );

    uint256 snapshotsCount = snapshotsCounts[user];

    if (snapshotsCount == 0) {
      return balanceOf(user);
    }

    // First check most recent balance
    if (snapshots[user][snapshotsCount - 1].blockNumber <= blockNumber) {
      return snapshots[user][snapshotsCount - 1].value;
    }

    // Next check implicit zero balance
    if (snapshots[user][0].blockNumber > blockNumber) {
      return 0;
    }

    uint256 lower = 0;
    uint256 upper = snapshotsCount - 1;
    while (upper > lower) {
      uint256 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
      Snapshot memory snapshot = snapshots[user][center];
      if (snapshot.blockNumber == blockNumber) {
        return snapshot.value;
      } else if (snapshot.blockNumber < blockNumber) {
        lower = center;
      } else {
        upper = center - 1;
      }
    }
    return snapshots[user][lower].value;
  }

  /**
   * @dev Returns delegation data (snapshot, snapshotsCount, delegates) by delegation type.
   *
   *  Note: This mixin contract does not itself define any storage, and we require the inheriting
   *  contract to implement this method to provide access to the relevant mappings in storage.
   *  This pattern was implemented by Aave for legacy reasons and we have decided not to change it.
   *
   * @param  delegationType  The type of power (VOTING_POWER, PROPOSITION_POWER).
   */
  function _getDelegationDataByType(
    DelegationType delegationType
  )
    internal
    virtual
    view
    returns (
      mapping(address => mapping(uint256 => Snapshot)) storage, // snapshots
      mapping(address => uint256) storage, // snapshotsCount
      mapping(address => address) storage // delegates
    );

  /**
   * @dev Writes a snapshot of a user's token/power balance.
   *
   * @param  snapshots        The mapping of snapshots by user.
   * @param  snapshotsCounts  The mapping of the number of snapshots by user.
   * @param  owner            The user whose power to snapshot.
   * @param  newValue         The new balance to snapshot at the current block.
   */
  function _writeSnapshot(
    mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
    mapping(address => uint256) storage snapshotsCounts,
    address owner,
    uint128 newValue
  )
    internal
  {
    uint128 currentBlock = uint128(block.number);

    uint256 ownerSnapshotsCount = snapshotsCounts[owner];
    mapping(uint256 => Snapshot) storage ownerSnapshots = snapshots[owner];

    if (
      ownerSnapshotsCount != 0 &&
      ownerSnapshots[ownerSnapshotsCount - 1].blockNumber == currentBlock
    ) {
      // Doing multiple operations in the same block
      ownerSnapshots[ownerSnapshotsCount - 1].value = newValue;
    } else {
      ownerSnapshots[ownerSnapshotsCount] = Snapshot(currentBlock, newValue);
      snapshotsCounts[owner] = ownerSnapshotsCount + 1;
    }
  }

  /**
   * @dev Returns the delegatee of a user. If a user never performed any delegation, their
   *  delegated address will be 0x0, in which case we return the user's own address.
   *
   * @param  delegator  The address of the user for which return the delegatee.
   * @param  delegates  The mapping of delegates for a particular type of delegation.
   */
  function _getDelegatee(
    address delegator,
    mapping(address => address) storage delegates
  )
    internal
    view
    returns (address)
  {
    address previousDelegatee = delegates[delegator];

    if (previousDelegatee == address(0)) {
      return delegator;
    }

    return previousDelegatee;
  }
}


// File contracts/governance/token/DydxToken.sol

pragma solidity 0.7.5;




/**
 * @title DydxToken
 * @author dYdX
 *
 * @notice The dYdX governance token.
 */
contract DydxToken is
  GovernancePowerDelegationERC20Mixin,
  Ownable
{
  using SafeMath for uint256;

  // ============ Events ============

  /**
   * @dev Emitted when an address has been added to or removed from the token transfer allowlist.
   *
   * @param  account    Address that was added to or removed from the token transfer allowlist.
   * @param  isAllowed  True if the address was added to the allowlist, false if removed.
   */
  event TransferAllowlistUpdated(
    address account,
    bool isAllowed
  );

  /**
   * @dev Emitted when the transfer restriction timestamp is reassigned.
   *
   * @param  transfersRestrictedBefore  The new timestamp on and after which non-allowlisted
   *                                    transfers may occur.
   */
  event TransfersRestrictedBeforeUpdated(
    uint256 transfersRestrictedBefore
  );

  // ============ Constants ============

  string internal constant NAME = 'dYdX';
  string internal constant SYMBOL = 'DYDX';

  uint256 public constant INITIAL_SUPPLY = 1_000_000_000 ether;

  bytes32 public immutable DOMAIN_SEPARATOR;
  bytes public constant EIP712_VERSION = '1';
  bytes32 public constant EIP712_DOMAIN = keccak256(
    'EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'
  );
  bytes32 public constant PERMIT_TYPEHASH = keccak256(
    'Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)'
  );

  /// @notice Minimum time between mints.
  uint256 public constant MINT_MIN_INTERVAL = 365 days;

  /// @notice Cap on the percentage of the total supply that can be minted at each mint.
  ///  Denominated in percentage points (units out of 100).
  uint256 public immutable MINT_MAX_PERCENT;

  /// @notice The timestamp on and after which the transfer restriction must be lifted.
  uint256 public immutable TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN;

  // ============ Storage ============

  /// @dev Mapping from (owner) => (next valid nonce) for EIP-712 signatures.
  mapping(address => uint256) internal _nonces;

  mapping(address => mapping(uint256 => Snapshot)) public _votingSnapshots;
  mapping(address => uint256) public _votingSnapshotsCounts;
  mapping(address => address) public _votingDelegates;

  mapping(address => mapping(uint256 => Snapshot)) public _propositionPowerSnapshots;
  mapping(address => uint256) public _propositionPowerSnapshotsCounts;
  mapping(address => address) public _propositionPowerDelegates;

  /// @notice Snapshots of the token total supply, at each block where the total supply has changed.
  mapping(uint256 => Snapshot) public _totalSupplySnapshots;

  /// @notice Number of snapshots of the token total supply.
  uint256 public _totalSupplySnapshotsCount;

  /// @notice Allowlist of addresses which may send or receive tokens while transfers are
  ///  otherwise restricted.
  mapping(address => bool) public _tokenTransferAllowlist;

  /// @notice The timestamp on and after which minting may occur.
  uint256 public _mintingRestrictedBefore;

  /// @notice The timestamp on and after which non-allowlisted transfers may occur.
  uint256 public _transfersRestrictedBefore;

  // ============ Constructor ============

  /**
   * @notice Constructor.
   *
   * @param  distributor                           The address which will receive the initial supply of tokens.
   * @param  transfersRestrictedBefore             Timestamp, before which transfers are restricted unless the
   *                                               origin or destination address is in the allowlist.
   * @param  transferRestrictionLiftedNoLaterThan  Timestamp, which is the maximum timestamp that transfer
   *                                               restrictions can be extended to.
   * @param  mintingRestrictedBefore               Timestamp, before which minting is not allowed.
   * @param  mintMaxPercent                        Cap on the percentage of the total supply that can be minted at
   *                                               each mint.
   */
  constructor(
    address distributor,
    uint256 transfersRestrictedBefore,
    uint256 transferRestrictionLiftedNoLaterThan,
    uint256 mintingRestrictedBefore,
    uint256 mintMaxPercent
  )
    ERC20(NAME, SYMBOL)
  {
    uint256 chainId;

    // solium-disable-next-line
    assembly {
      chainId := chainid()
    }

    DOMAIN_SEPARATOR = keccak256(
      abi.encode(
        EIP712_DOMAIN,
        keccak256(bytes(NAME)),
        keccak256(bytes(EIP712_VERSION)),
        chainId,
        address(this)
      )
    );

    // Validate and set parameters.
    require(
      transfersRestrictedBefore > block.timestamp,
      'TRANSFERS_RESTRICTED_BEFORE_TOO_EARLY'
    );
    require(
      transfersRestrictedBefore <= transferRestrictionLiftedNoLaterThan,
      'MAX_TRANSFER_RESTRICTION_TOO_EARLY'
    );
    require(
      mintingRestrictedBefore > block.timestamp,
      'MINTING_RESTRICTED_BEFORE_TOO_EARLY'
    );
    _transfersRestrictedBefore = transfersRestrictedBefore;
    TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN = transferRestrictionLiftedNoLaterThan;
    _mintingRestrictedBefore = mintingRestrictedBefore;
    MINT_MAX_PERCENT = mintMaxPercent;

    // Mint the initial supply.
    _mint(distributor, INITIAL_SUPPLY);

    emit TransfersRestrictedBeforeUpdated(transfersRestrictedBefore);
  }

  // ============ Other Functions ============

  /**
   * @notice Adds addresses to the token transfer allowlist. Reverts if any of the addresses
   *  already exist in the allowlist. Only callable by owner.
   *
   * @param  addressesToAdd  Addresses to add to the token transfer allowlist.
   */
  function addToTokenTransferAllowlist(
    address[] calldata addressesToAdd
  )
    external
    onlyOwner
  {
    for (uint256 i = 0; i < addressesToAdd.length; i++) {
      require(
        !_tokenTransferAllowlist[addressesToAdd[i]],
        'ADDRESS_EXISTS_IN_TRANSFER_ALLOWLIST'
      );
      _tokenTransferAllowlist[addressesToAdd[i]] = true;
      emit TransferAllowlistUpdated(addressesToAdd[i], true);
    }
  }

  /**
   * @notice Removes addresses from the token transfer allowlist. Reverts if any of the addresses
   *  don't exist in the allowlist. Only callable by owner.
   *
   * @param  addressesToRemove  Addresses to remove from the token transfer allowlist.
   */
  function removeFromTokenTransferAllowlist(
    address[] calldata addressesToRemove
  )
    external
    onlyOwner
  {
    for (uint256 i = 0; i < addressesToRemove.length; i++) {
      require(
        _tokenTransferAllowlist[addressesToRemove[i]],
        'ADDRESS_DOES_NOT_EXIST_IN_TRANSFER_ALLOWLIST'
      );
      _tokenTransferAllowlist[addressesToRemove[i]] = false;
      emit TransferAllowlistUpdated(addressesToRemove[i], false);
    }
  }

  /**
   * @notice Updates the transfer restriction. Reverts if the transfer restriction has already passed,
   *  the new transfer restriction is earlier than the previous one, or the new transfer restriction is
   *  after the maximum transfer restriction.
   *
   * @param  transfersRestrictedBefore  The timestamp on and after which non-allowlisted transfers may occur.
   */
  function updateTransfersRestrictedBefore(
    uint256 transfersRestrictedBefore
  )
    external
    onlyOwner
  {
    uint256 previousTransfersRestrictedBefore = _transfersRestrictedBefore;
    require(
      block.timestamp < previousTransfersRestrictedBefore,
      'TRANSFER_RESTRICTION_ENDED'
    );
    require(
      previousTransfersRestrictedBefore <= transfersRestrictedBefore,
      'NEW_TRANSFER_RESTRICTION_TOO_EARLY'
    );
    require(
      transfersRestrictedBefore <= TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN,
      'AFTER_MAX_TRANSFER_RESTRICTION'
    );

    _transfersRestrictedBefore = transfersRestrictedBefore;

    emit TransfersRestrictedBeforeUpdated(transfersRestrictedBefore);
  }

  /**
   * @notice Mint new tokens. Only callable by owner after the required time period has elapsed.
   *
   * @param  recipient  The address to receive minted tokens.
   * @param  amount     The number of tokens to mint.
   */
  function mint(
    address recipient,
    uint256 amount
  )
    external
    onlyOwner
  {
    require(
      block.timestamp >= _mintingRestrictedBefore,
      'MINT_TOO_EARLY'
    );
    require(
      amount <= totalSupply().mul(MINT_MAX_PERCENT).div(100),
      'MAX_MINT_EXCEEDED'
    );

    // Update the next allowed minting time.
    _mintingRestrictedBefore = block.timestamp.add(MINT_MIN_INTERVAL);

    // Mint the amount.
    _mint(recipient, amount);
  }

  /**
   * @notice Implements the permit function as specified in EIP-2612.
   *
   * @param  owner     Address of the token owner.
   * @param  spender   Address of the spender.
   * @param  value     Amount of allowance.
   * @param  deadline  Expiration timestamp for the signature.
   * @param  v         Signature param.
   * @param  r         Signature param.
   * @param  s         Signature param.
   */
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  )
    external
  {
    require(
      owner != address(0),
      'INVALID_OWNER'
    );
    require(
      block.timestamp <= deadline,
      'INVALID_EXPIRATION'
    );
    uint256 currentValidNonce = _nonces[owner];
    bytes32 digest = keccak256(
      abi.encodePacked(
        '\x19\x01',
        DOMAIN_SEPARATOR,
        keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, currentValidNonce, deadline))
      )
    );

    require(
      owner == ecrecover(digest, v, r, s),
      'INVALID_SIGNATURE'
    );
    _nonces[owner] = currentValidNonce.add(1);
    _approve(owner, spender, value);
  }

  /**
   * @notice Get the next valid nonce for EIP-712 signatures.
   *
   *  This nonce should be used when signing for any of the following functions:
   *   - permit()
   *   - delegateByTypeBySig()
   *   - delegateBySig()
   */
  function nonces(
    address owner
  )
    external
    view
    returns (uint256)
  {
    return _nonces[owner];
  }

  function transfer(
    address recipient,
    uint256 amount
  )
    public
    override
    returns (bool)
  {
    _requireTransferAllowed(_msgSender(), recipient);
    return super.transfer(recipient, amount);
  }

  function transferFrom(
    address sender,
    address recipient,
    uint256 amount
  )
    public
    override
    returns (bool)
  {
    _requireTransferAllowed(sender, recipient);
    return super.transferFrom(sender, recipient, amount);
  }

  /**
   * @dev Override _mint() to write a snapshot whenever the total supply changes.
   *
   *  These snapshots are intended to be used by the governance strategy.
   *
   *  Note that the ERC20 _burn() function is never used. If desired, an official burn mechanism
   *  could be implemented external to this contract, and accounted for in the governance strategy.
   */
  function _mint(
    address account,
    uint256 amount
  )
    internal
    override
  {
    super._mint(account, amount);

    uint256 snapshotsCount = _totalSupplySnapshotsCount;
    uint128 currentBlock = uint128(block.number);
    uint128 newValue = uint128(totalSupply());

    // Note: There is no special case for the total supply being updated multiple times in the same
    // block. That should never occur.
    _totalSupplySnapshots[snapshotsCount] = Snapshot(currentBlock, newValue);
    _totalSupplySnapshotsCount = snapshotsCount.add(1);
  }

  function _requireTransferAllowed(
    address sender,
    address recipient
  )
    view
    internal
  {
    // Compare against the constant `TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN` first
    // to avoid additional gas costs from reading from storage.
    if (
      block.timestamp < TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN &&
      block.timestamp < _transfersRestrictedBefore
    ) {
      // While transfers are restricted, a transfer is permitted if either the sender or the
      // recipient is on the allowlist.
      require(
        _tokenTransferAllowlist[sender] || _tokenTransferAllowlist[recipient],
        'NON_ALLOWLIST_TRANSFERS_DISABLED'
      );
    }
  }

  /**
   * @dev Writes a snapshot before any transfer operation, including: _transfer, _mint and _burn.
   *  - On _transfer, it writes snapshots for both 'from' and 'to'.
   *  - On _mint, only for `to`.
   *  - On _burn, only for `from`.
   *
   * @param  from    The sender.
   * @param  to      The recipient.
   * @param  amount  The amount being transfered.
   */
  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 amount
  )
    internal
    override
  {
    address votingFromDelegatee = _getDelegatee(from, _votingDelegates);
    address votingToDelegatee = _getDelegatee(to, _votingDelegates);

    _moveDelegatesByType(
      votingFromDelegatee,
      votingToDelegatee,
      amount,
      DelegationType.VOTING_POWER
    );

    address propPowerFromDelegatee = _getDelegatee(from, _propositionPowerDelegates);
    address propPowerToDelegatee = _getDelegatee(to, _propositionPowerDelegates);

    _moveDelegatesByType(
      propPowerFromDelegatee,
      propPowerToDelegatee,
      amount,
      DelegationType.PROPOSITION_POWER
    );
  }

  function _getDelegationDataByType(
    DelegationType delegationType
  )
    internal
    override
    view
    returns (
      mapping(address => mapping(uint256 => Snapshot)) storage, // snapshots
      mapping(address => uint256) storage, // snapshots count
      mapping(address => address) storage // delegatees list
    )
  {
    if (delegationType == DelegationType.VOTING_POWER) {
      return (_votingSnapshots, _votingSnapshotsCounts, _votingDelegates);
    } else {
      return (
        _propositionPowerSnapshots,
        _propositionPowerSnapshotsCounts,
        _propositionPowerDelegates
      );
    }
  }

  /**
   * @dev Delegates specific governance power from signer to `delegatee` using an EIP-712 signature.
   *
   * @param  delegatee       The address to delegate votes to.
   * @param  delegationType  The type of delegation (VOTING_POWER, PROPOSITION_POWER).
   * @param  nonce           The signer's nonce for EIP-712 signatures on this contract.
   * @param  expiry          Expiration timestamp for the signature.
   * @param  v               Signature param.
   * @param  r               Signature param.
   * @param  s               Signature param.
   */
  function delegateByTypeBySig(
    address delegatee,
    DelegationType delegationType,
    uint256 nonce,
    uint256 expiry,
    uint8 v,
    bytes32 r,
    bytes32 s
  )
    public
  {
    bytes32 structHash = keccak256(
      abi.encode(DELEGATE_BY_TYPE_TYPEHASH, delegatee, uint256(delegationType), nonce, expiry)
    );
    bytes32 digest = keccak256(abi.encodePacked('\x19\x01', DOMAIN_SEPARATOR, structHash));
    address signer = ecrecover(digest, v, r, s);
    require(
      signer != address(0),
      'INVALID_SIGNATURE'
    );
    require(
      nonce == _nonces[signer]++,
      'INVALID_NONCE'
    );
    require(
      block.timestamp <= expiry,
      'INVALID_EXPIRATION'
    );
    _delegateByType(signer, delegatee, delegationType);
  }

  /**
   * @dev Delegates both governance powers from signer to `delegatee` using an EIP-712 signature.
   *
   * @param  delegatee  The address to delegate votes to.
   * @param  nonce      The signer's nonce for EIP-712 signatures on this contract.
   * @param  expiry     Expiration timestamp for the signature.
   * @param  v          Signature param.
   * @param  r          Signature param.
   * @param  s          Signature param.
   */
  function delegateBySig(
    address delegatee,
    uint256 nonce,
    uint256 expiry,
    uint8 v,
    bytes32 r,
    bytes32 s
  )
    public
  {
    bytes32 structHash = keccak256(abi.encode(DELEGATE_TYPEHASH, delegatee, nonce, expiry));
    bytes32 digest = keccak256(abi.encodePacked('\x19\x01', DOMAIN_SEPARATOR, structHash));
    address signer = ecrecover(digest, v, r, s);
    require(
      signer != address(0),
      'INVALID_SIGNATURE'
    );
    require(
      nonce == _nonces[signer]++,
      'INVALID_NONCE'
    );
    require(
      block.timestamp <= expiry,
      'INVALID_EXPIRATION'
    );
    _delegateByType(signer, delegatee, DelegationType.VOTING_POWER);
    _delegateByType(signer, delegatee, DelegationType.PROPOSITION_POWER);
  }
}

/**
Matic network contracts
*/

pragma solidity ^0.5.2;


contract Ownable {
    address private _owner;

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

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

library SafeMath {
    /**
     * @dev Multiplies two unsigned integers, reverts on overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (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-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two unsigned integers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

contract StateSender is Ownable {
    using SafeMath for uint256;

    uint256 public counter;
    mapping(address => address) public registrations;

    event NewRegistration(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event RegistrationUpdated(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event StateSynced(
        uint256 indexed id,
        address indexed contractAddress,
        bytes data
    );

    modifier onlyRegistered(address receiver) {
        require(registrations[receiver] == msg.sender, "Invalid sender");
        _;
    }

    function syncState(address receiver, bytes calldata data)
        external
        onlyRegistered(receiver)
    {
        counter = counter.add(1);
        emit StateSynced(counter, receiver, data);
    }

    // register new contract for state sync
    function register(address sender, address receiver) public {
        require(
            isOwner() || registrations[receiver] == msg.sender,
            "StateSender.register: Not authorized to register"
        );
        registrations[receiver] = sender;
        if (registrations[receiver] == address(0)) {
            emit NewRegistration(msg.sender, sender, receiver);
        } else {
            emit RegistrationUpdated(msg.sender, sender, receiver);
        }
    }
}

pragma solidity 0.6.6;
import {SafeMath} from "@openzeppelin/contracts/math/SafeMath.sol";
import {IRootChainManager} from "./IRootChainManager.sol";
import {RootChainManagerStorage} from "./RootChainManagerStorage.sol";
import {IStateSender} from "../StateSender/IStateSender.sol";
import {ICheckpointManager} from "../ICheckpointManager.sol";
import {RLPReader} from "../../lib/RLPReader.sol";
import {ExitPayloadReader} from "../../lib/ExitPayloadReader.sol";
import {MerklePatriciaProof} from "../../lib/MerklePatriciaProof.sol";
import {Merkle} from "../../lib/Merkle.sol";
import {ITokenPredicate} from "../TokenPredicates/ITokenPredicate.sol";
import {Initializable} from "../../common/Initializable.sol";
import {NativeMetaTransaction} from "../../common/NativeMetaTransaction.sol";
import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
import {AccessControlMixin} from "../../common/AccessControlMixin.sol";
import {ContextMixin} from "../../common/ContextMixin.sol";
contract RootChainManager is
    IRootChainManager,
    Initializable,
    AccessControl, // included to match old storage layout while upgrading
    RootChainManagerStorage, // created to match old storage layout while upgrading
    AccessControlMixin,
    NativeMetaTransaction,
    ContextMixin
{
    using ExitPayloadReader for bytes;
    using ExitPayloadReader for ExitPayloadReader.ExitPayload;
    using ExitPayloadReader for ExitPayloadReader.Log;
    using ExitPayloadReader for ExitPayloadReader.Receipt;
    using Merkle for bytes32;
    using SafeMath for uint256;
    // maybe DEPOSIT and MAP_TOKEN can be reduced to bytes4
    bytes32 public constant DEPOSIT = keccak256("DEPOSIT");
    bytes32 public constant MAP_TOKEN = keccak256("MAP_TOKEN");
    address public constant ETHER_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    bytes32 public constant MAPPER_ROLE = keccak256("MAPPER_ROLE");
    constructor() public {
        // Disable initializer on implementation contract
        _disableInitializer();
    }
    function _msgSender()
        internal
        override
        view
        returns (address payable sender)
    {
        return ContextMixin.msgSender();
    }
    /**
     * @notice Deposit ether by directly sending to the contract
     * The account sending ether receives WETH on child chain
     */
    receive() external payable {
        _depositEtherFor(_msgSender());
    }
    /**
     * @notice Initialize the contract after it has been proxified
     * @dev meant to be called once immediately after deployment
     * @param _owner the account that should be granted admin role
     */
    function initialize(
        address _owner
    )
        external
        initializer
    {
        _initializeEIP712("RootChainManager");
        _setupContractId("RootChainManager");
        _setupRole(DEFAULT_ADMIN_ROLE, _owner);
        _setupRole(MAPPER_ROLE, _owner);
    }
    // adding seperate function setupContractId since initialize is already called with old implementation
    function setupContractId()
        external
        only(DEFAULT_ADMIN_ROLE)
    {
        _setupContractId("RootChainManager");
    }
    // adding seperate function initializeEIP712 since initialize is already called with old implementation
    function initializeEIP712()
        external
        only(DEFAULT_ADMIN_ROLE)
    {
        _setDomainSeperator("RootChainManager");
    }
    /**
     * @notice Set the state sender, callable only by admins
     * @dev This should be the state sender from plasma contracts
     * It is used to send bytes from root to child chain
     * @param newStateSender address of state sender contract
     */
    function setStateSender(address newStateSender)
        external
        only(DEFAULT_ADMIN_ROLE)
    {
        require(newStateSender != address(0), "RootChainManager: BAD_NEW_STATE_SENDER");
        _stateSender = IStateSender(newStateSender);
    }
    /**
     * @notice Get the address of contract set as state sender
     * @return The address of state sender contract
     */
    function stateSenderAddress() external view returns (address) {
        return address(_stateSender);
    }
    /**
     * @notice Set the checkpoint manager, callable only by admins
     * @dev This should be the plasma contract responsible for keeping track of checkpoints
     * @param newCheckpointManager address of checkpoint manager contract
     */
    function setCheckpointManager(address newCheckpointManager)
        external
        only(DEFAULT_ADMIN_ROLE)
    {
        require(newCheckpointManager != address(0), "RootChainManager: BAD_NEW_CHECKPOINT_MANAGER");
        _checkpointManager = ICheckpointManager(newCheckpointManager);
    }
    /**
     * @notice Get the address of contract set as checkpoint manager
     * @return The address of checkpoint manager contract
     */
    function checkpointManagerAddress() external view returns (address) {
        return address(_checkpointManager);
    }
    /**
     * @notice Set the child chain manager, callable only by admins
     * @dev This should be the contract responsible to receive deposit bytes on child chain
     * @param newChildChainManager address of child chain manager contract
     */
    function setChildChainManagerAddress(address newChildChainManager)
        external
        only(DEFAULT_ADMIN_ROLE)
    {
        require(newChildChainManager != address(0x0), "RootChainManager: INVALID_CHILD_CHAIN_ADDRESS");
        childChainManagerAddress = newChildChainManager;
    }
    /**
     * @notice Register a token predicate address against its type, callable only by ADMIN
     * @dev A predicate is a contract responsible to process the token specific logic while locking or exiting tokens
     * @param tokenType bytes32 unique identifier for the token type
     * @param predicateAddress address of token predicate address
     */
    function registerPredicate(bytes32 tokenType, address predicateAddress)
        external
        override
        only(DEFAULT_ADMIN_ROLE)
    {
        typeToPredicate[tokenType] = predicateAddress;
        emit PredicateRegistered(tokenType, predicateAddress);
    }
    /**
     * @notice Map a token to enable its movement via the PoS Portal, callable only by mappers
     * @param rootToken address of token on root chain
     * @param childToken address of token on child chain
     * @param tokenType bytes32 unique identifier for the token type
     */
    function mapToken(
        address rootToken,
        address childToken,
        bytes32 tokenType
    ) external override only(MAPPER_ROLE) {
        // explicit check if token is already mapped to avoid accidental remaps
        require(
            rootToChildToken[rootToken] == address(0) &&
            childToRootToken[childToken] == address(0),
            "RootChainManager: ALREADY_MAPPED"
        );
        _mapToken(rootToken, childToken, tokenType);
    }
    /**
     * @notice Clean polluted token mapping
     * @param rootToken address of token on root chain. Since rename token was introduced later stage,
     * clean method is used to clean pollulated mapping
     */
    function cleanMapToken(
        address rootToken,
        address childToken
    ) external override only(DEFAULT_ADMIN_ROLE) {
        rootToChildToken[rootToken] = address(0);
        childToRootToken[childToken] = address(0);
        tokenToType[rootToken] = bytes32(0);
        emit TokenMapped(rootToken, childToken, tokenToType[rootToken]);
    }
    /**
     * @notice Remap a token that has already been mapped, properly cleans up old mapping
     * Callable only by ADMIN
     * @param rootToken address of token on root chain
     * @param childToken address of token on child chain
     * @param tokenType bytes32 unique identifier for the token type
     */
    function remapToken(
        address rootToken,
        address childToken,
        bytes32 tokenType
    ) external override only(DEFAULT_ADMIN_ROLE) {
        // cleanup old mapping
        address oldChildToken = rootToChildToken[rootToken];
        address oldRootToken = childToRootToken[childToken];
        if (rootToChildToken[oldRootToken] != address(0)) {
            rootToChildToken[oldRootToken] = address(0);
            tokenToType[oldRootToken] = bytes32(0);
        }
        if (childToRootToken[oldChildToken] != address(0)) {
            childToRootToken[oldChildToken] = address(0);
        }
        _mapToken(rootToken, childToken, tokenType);
    }
    function _mapToken(
        address rootToken,
        address childToken,
        bytes32 tokenType
    ) private {
        require(
            typeToPredicate[tokenType] != address(0x0),
            "RootChainManager: TOKEN_TYPE_NOT_SUPPORTED"
        );
        rootToChildToken[rootToken] = childToken;
        childToRootToken[childToken] = rootToken;
        tokenToType[rootToken] = tokenType;
        emit TokenMapped(rootToken, childToken, tokenType);
        bytes memory syncData = abi.encode(rootToken, childToken, tokenType);
        _stateSender.syncState(
            childChainManagerAddress,
            abi.encode(MAP_TOKEN, syncData)
        );
    }
    /**
     * @notice Move ether from root to child chain, accepts ether transfer
     * Keep in mind this ether cannot be used to pay gas on child chain
     * Use Matic tokens deposited using plasma mechanism for that
     * @param user address of account that should receive WETH on child chain
     */
    function depositEtherFor(address user) external override payable {
        _depositEtherFor(user);
    }
    /**
     * @notice Move tokens from root to child chain
     * @dev This mechanism supports arbitrary tokens as long as its predicate has been registered and the token is mapped
     * @param user address of account that should receive this deposit on child chain
     * @param rootToken address of token that is being deposited
     * @param depositData bytes data that is sent to predicate and child token contracts to handle deposit
     */
    function depositFor(
        address user,
        address rootToken,
        bytes calldata depositData
    ) external override {
        require(
            rootToken != ETHER_ADDRESS,
            "RootChainManager: INVALID_ROOT_TOKEN"
        );
        _depositFor(user, rootToken, depositData);
    }
    function _depositEtherFor(address user) private {
        bytes memory depositData = abi.encode(msg.value);
        _depositFor(user, ETHER_ADDRESS, depositData);
        // payable(typeToPredicate[tokenToType[ETHER_ADDRESS]]).transfer(msg.value);
        // transfer doesn't work as expected when receiving contract is proxified so using call
        (bool success, /* bytes memory data */) = typeToPredicate[tokenToType[ETHER_ADDRESS]].call{value: msg.value}("");
        if (!success) {
            revert("RootChainManager: ETHER_TRANSFER_FAILED");
        }
    }
    function _depositFor(
        address user,
        address rootToken,
        bytes memory depositData
    ) private {
        bytes32 tokenType = tokenToType[rootToken];
        require(
            rootToChildToken[rootToken] != address(0x0) &&
               tokenType != 0,
            "RootChainManager: TOKEN_NOT_MAPPED"
        );
        address predicateAddress = typeToPredicate[tokenType];
        require(
            predicateAddress != address(0),
            "RootChainManager: INVALID_TOKEN_TYPE"
        );
        require(
            user != address(0),
            "RootChainManager: INVALID_USER"
        );
        ITokenPredicate(predicateAddress).lockTokens(
            _msgSender(),
            user,
            rootToken,
            depositData
        );
        bytes memory syncData = abi.encode(user, rootToken, depositData);
        _stateSender.syncState(
            childChainManagerAddress,
            abi.encode(DEPOSIT, syncData)
        );
    }
    /**
     * @notice exit tokens by providing proof
     * @dev This function verifies if the transaction actually happened on child chain
     * the transaction log is then sent to token predicate to handle it accordingly
     *
     * @param inputData RLP encoded data of the reference tx containing following list of fields
     *  0 - headerNumber - Checkpoint header block number containing the reference tx
     *  1 - blockProof - Proof that the block header (in the child chain) is a leaf in the submitted merkle root
     *  2 - blockNumber - Block number containing the reference tx on child chain
     *  3 - blockTime - Reference tx block time
     *  4 - txRoot - Transactions root of block
     *  5 - receiptRoot - Receipts root of block
     *  6 - receipt - Receipt of the reference transaction
     *  7 - receiptProof - Merkle proof of the reference receipt
     *  8 - branchMask - 32 bits denoting the path of receipt in merkle tree
     *  9 - receiptLogIndex - Log Index to read from the receipt
     */
    function exit(bytes calldata inputData) external override {
        ExitPayloadReader.ExitPayload memory payload = inputData.toExitPayload();
        bytes memory branchMaskBytes = payload.getBranchMaskAsBytes();
        // checking if exit has already been processed
        // unique exit is identified using hash of (blockNumber, branchMask, receiptLogIndex)
        bytes32 exitHash = keccak256(
            abi.encodePacked(
                payload.getBlockNumber(),
                // first 2 nibbles are dropped while generating nibble array
                // this allows branch masks that are valid but bypass exitHash check (changing first 2 nibbles only)
                // so converting to nibble array and then hashing it
                MerklePatriciaProof._getNibbleArray(branchMaskBytes),
                payload.getReceiptLogIndex()
            )
        );
        require(
            processedExits[exitHash] == false,
            "RootChainManager: EXIT_ALREADY_PROCESSED"
        );
        processedExits[exitHash] = true;
        ExitPayloadReader.Receipt memory receipt = payload.getReceipt();
        ExitPayloadReader.Log memory log = receipt.getLog();
        // log should be emmited only by the child token
        address rootToken = childToRootToken[log.getEmitter()];
        require(
            rootToken != address(0),
            "RootChainManager: TOKEN_NOT_MAPPED"
        );
        address predicateAddress = typeToPredicate[
            tokenToType[rootToken]
        ];
        // branch mask can be maximum 32 bits
        require(
            payload.getBranchMaskAsUint() &
            0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000 ==
            0,
            "RootChainManager: INVALID_BRANCH_MASK"
        );
        // verify receipt inclusion
        require(
            MerklePatriciaProof.verify(
                receipt.toBytes(),
                branchMaskBytes,
                payload.getReceiptProof(),
                payload.getReceiptRoot()
            ),
            "RootChainManager: INVALID_PROOF"
        );
        // verify checkpoint inclusion
        _checkBlockMembershipInCheckpoint(
            payload.getBlockNumber(),
            payload.getBlockTime(),
            payload.getTxRoot(),
            payload.getReceiptRoot(),
            payload.getHeaderNumber(),
            payload.getBlockProof()
        );
        ITokenPredicate(predicateAddress).exitTokens(
            _msgSender(),
            rootToken,
            log.toRlpBytes()
        );
    }
    function _checkBlockMembershipInCheckpoint(
        uint256 blockNumber,
        uint256 blockTime,
        bytes32 txRoot,
        bytes32 receiptRoot,
        uint256 headerNumber,
        bytes memory blockProof
    ) private view {
        (
            bytes32 headerRoot,
            uint256 startBlock,
            ,
            ,
        ) = _checkpointManager.headerBlocks(headerNumber);
        require(
            keccak256(
                abi.encodePacked(blockNumber, blockTime, txRoot, receiptRoot)
            )
                .checkMembership(
                blockNumber.sub(startBlock),
                headerRoot,
                blockProof
            ),
            "RootChainManager: INVALID_HEADER"
        );
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
 * @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, 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) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * 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);
        uint256 c = a - b;
        return c;
    }
    /**
     * @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) {
        // 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 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts 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) {
        return div(a, b, "SafeMath: division by zero");
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts 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) {
        return mod(a, b, "SafeMath: modulo by zero");
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}
pragma solidity 0.6.6;
interface IRootChainManager {
    event TokenMapped(
        address indexed rootToken,
        address indexed childToken,
        bytes32 indexed tokenType
    );
    event PredicateRegistered(
        bytes32 indexed tokenType,
        address indexed predicateAddress
    );
    function registerPredicate(bytes32 tokenType, address predicateAddress)
        external;
    function mapToken(
        address rootToken,
        address childToken,
        bytes32 tokenType
    ) external;
    function cleanMapToken(
        address rootToken,
        address childToken
    ) external;
    function remapToken(
        address rootToken,
        address childToken,
        bytes32 tokenType
    ) external;
    function depositEtherFor(address user) external payable;
    function depositFor(
        address user,
        address rootToken,
        bytes calldata depositData
    ) external;
    function exit(bytes calldata inputData) external;
}
pragma solidity 0.6.6;
import {IStateSender} from "../StateSender/IStateSender.sol";
import {ICheckpointManager} from "../ICheckpointManager.sol";
abstract contract RootChainManagerStorage {
    mapping(bytes32 => address) public typeToPredicate;
    mapping(address => address) public rootToChildToken;
    mapping(address => address) public childToRootToken;
    mapping(address => bytes32) public tokenToType;
    mapping(bytes32 => bool) public processedExits;
    IStateSender internal _stateSender;
    ICheckpointManager internal _checkpointManager;
    address public childChainManagerAddress;
}
pragma solidity 0.6.6;
interface IStateSender {
    function syncState(address receiver, bytes calldata data) external;
}
pragma solidity 0.6.6;
contract ICheckpointManager {
    struct HeaderBlock {
        bytes32 root;
        uint256 start;
        uint256 end;
        uint256 createdAt;
        address proposer;
    }
    /**
     * @notice mapping of checkpoint header numbers to block details
     * @dev These checkpoints are submited by plasma contracts
     */
    mapping(uint256 => HeaderBlock) public headerBlocks;
}
/*
 * @author Hamdi Allam [email protected]
 * Please reach out with any questions or concerns
 * https://github.com/hamdiallam/Solidity-RLP/blob/e681e25a376dbd5426b509380bc03446f05d0f97/contracts/RLPReader.sol
 */
pragma solidity 0.6.6;
library RLPReader {
    uint8 constant STRING_SHORT_START = 0x80;
    uint8 constant STRING_LONG_START  = 0xb8;
    uint8 constant LIST_SHORT_START   = 0xc0;
    uint8 constant LIST_LONG_START    = 0xf8;
    uint8 constant WORD_SIZE = 32;
    struct RLPItem {
        uint len;
        uint memPtr;
    }
    struct Iterator {
        RLPItem item;   // Item that's being iterated over.
        uint nextPtr;   // Position of the next item in the list.
    }
    /*
    * @dev Returns the next element in the iteration. Reverts if it has not next element.
    * @param self The iterator.
    * @return The next element in the iteration.
    */
    function next(Iterator memory self) internal pure returns (RLPItem memory) {
        require(hasNext(self));
        uint ptr = self.nextPtr;
        uint itemLength = _itemLength(ptr);
        self.nextPtr = ptr + itemLength;
        return RLPItem(itemLength, ptr);
    }
    /*
    * @dev Returns true if the iteration has more elements.
    * @param self The iterator.
    * @return true if the iteration has more elements.
    */
    function hasNext(Iterator memory self) internal pure returns (bool) {
        RLPItem memory item = self.item;
        return self.nextPtr < item.memPtr + item.len;
    }
    /*
    * @param item RLP encoded bytes
    */
    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
        uint memPtr;
        assembly {
            memPtr := add(item, 0x20)
        }
        return RLPItem(item.length, memPtr);
    }
    /*
    * @dev Create an iterator. Reverts if item is not a list.
    * @param self The RLP item.
    * @return An 'Iterator' over the item.
    */
    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
        require(isList(self));
        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }
    /*
    * @param the RLP item.
    */
    function rlpLen(RLPItem memory item) internal pure returns (uint) {
        return item.len;
    }
    /*
     * @param the RLP item.
     * @return (memPtr, len) pair: location of the item's payload in memory.
     */
    function payloadLocation(RLPItem memory item) internal pure returns (uint, uint) {
        uint offset = _payloadOffset(item.memPtr);
        uint memPtr = item.memPtr + offset;
        uint len = item.len - offset; // data length
        return (memPtr, len);
    }
    /*
    * @param the RLP item.
    */
    function payloadLen(RLPItem memory item) internal pure returns (uint) {
        (, uint len) = payloadLocation(item);
        return len;
    }
    /*
    * @param the RLP item containing the encoded list.
    */
    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
        require(isList(item));
        uint items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);
        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint dataLen;
        for (uint i = 0; i < items; i++) {
            dataLen = _itemLength(memPtr);
            result[i] = RLPItem(dataLen, memPtr); 
            memPtr = memPtr + dataLen;
        }
        require(memPtr - item.memPtr == item.len, "Wrong total length.");
        return result;
    }
    // @return indicator whether encoded payload is a list. negate this function call for isData.
    function isList(RLPItem memory item) internal pure returns (bool) {
        if (item.len == 0) return false;
        uint8 byte0;
        uint memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }
        if (byte0 < LIST_SHORT_START)
            return false;
        return true;
    }
    /*
     * @dev A cheaper version of keccak256(toRlpBytes(item)) that avoids copying memory.
     * @return keccak256 hash of RLP encoded bytes.
     */
    function rlpBytesKeccak256(RLPItem memory item) internal pure returns (bytes32) {
        uint256 ptr = item.memPtr;
        uint256 len = item.len;
        bytes32 result;
        assembly {
            result := keccak256(ptr, len)
        }
        return result;
    }
    /*
     * @dev A cheaper version of keccak256(toBytes(item)) that avoids copying memory.
     * @return keccak256 hash of the item payload.
     */
    function payloadKeccak256(RLPItem memory item) internal pure returns (bytes32) {
        (uint memPtr, uint len) = payloadLocation(item);
        bytes32 result;
        assembly {
            result := keccak256(memPtr, len)
        }
        return result;
    }
    /** RLPItem conversions into data types **/
    // @returns raw rlp encoding in bytes
    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
        bytes memory result = new bytes(item.len);
        if (result.length == 0) return result;
        
        uint ptr;
        assembly {
            ptr := add(0x20, result)
        }
        copy(item.memPtr, ptr, item.len);
        return result;
    }
    // any non-zero byte except "0x80" is considered true
    function toBoolean(RLPItem memory item) internal pure returns (bool) {
        require(item.len == 1);
        uint result;
        uint memPtr = item.memPtr;
        assembly {
            result := byte(0, mload(memPtr))
        }
        // SEE Github Issue #5.
        // Summary: Most commonly used RLP libraries (i.e Geth) will encode
        // "0" as "0x80" instead of as "0". We handle this edge case explicitly
        // here.
        if (result == 0 || result == STRING_SHORT_START) {
            return false;
        } else {
            return true;
        }
    }
    function toAddress(RLPItem memory item) internal pure returns (address) {
        // 1 byte for the length prefix
        require(item.len == 21);
        return address(toUint(item));
    }
    function toUint(RLPItem memory item) internal pure returns (uint) {
        require(item.len > 0 && item.len <= 33);
        (uint memPtr, uint len) = payloadLocation(item);
        uint result;
        assembly {
            result := mload(memPtr)
            // shfit to the correct location if neccesary
            if lt(len, 32) {
                result := div(result, exp(256, sub(32, len)))
            }
        }
        return result;
    }
    // enforces 32 byte length
    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
        // one byte prefix
        require(item.len == 33);
        uint result;
        uint memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }
        return result;
    }
    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
        require(item.len > 0);
        (uint memPtr, uint len) = payloadLocation(item);
        bytes memory result = new bytes(len);
        uint destPtr;
        assembly {
            destPtr := add(0x20, result)
        }
        copy(memPtr, destPtr, len);
        return result;
    }
    /*
    * Private Helpers
    */
    // @return number of payload items inside an encoded list.
    function numItems(RLPItem memory item) private pure returns (uint) {
        if (item.len == 0) return 0;
        uint count = 0;
        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint endPtr = item.memPtr + item.len;
        while (currPtr < endPtr) {
           currPtr = currPtr + _itemLength(currPtr); // skip over an item
           count++;
        }
        return count;
    }
    // @return entire rlp item byte length
    function _itemLength(uint memPtr) private pure returns (uint) {
        uint itemLen;
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }
        if (byte0 < STRING_SHORT_START)
            itemLen = 1;
        
        else if (byte0 < STRING_LONG_START)
            itemLen = byte0 - STRING_SHORT_START + 1;
        else if (byte0 < LIST_SHORT_START) {
            assembly {
                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
                memPtr := add(memPtr, 1) // skip over the first byte
                
                /* 32 byte word size */
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }
        else if (byte0 < LIST_LONG_START) {
            itemLen = byte0 - LIST_SHORT_START + 1;
        } 
        else {
            assembly {
                let byteLen := sub(byte0, 0xf7)
                memPtr := add(memPtr, 1)
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }
        return itemLen;
    }
    // @return number of bytes until the data
    function _payloadOffset(uint memPtr) private pure returns (uint) {
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }
        if (byte0 < STRING_SHORT_START) 
            return 0;
        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
            return 1;
        else if (byte0 < LIST_SHORT_START)  // being explicit
            return byte0 - (STRING_LONG_START - 1) + 1;
        else
            return byte0 - (LIST_LONG_START - 1) + 1;
    }
    /*
    * @param src Pointer to source
    * @param dest Pointer to destination
    * @param len Amount of memory to copy from the source
    */
    function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;
        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }
            src += WORD_SIZE;
            dest += WORD_SIZE;
        }
        if (len > 0) {
            // left over bytes. Mask is used to remove unwanted bytes from the word
            uint mask = 256 ** (WORD_SIZE - len) - 1;
            assembly {
                let srcpart := and(mload(src), not(mask)) // zero out src
                let destpart := and(mload(dest), mask) // retrieve the bytes
                mstore(dest, or(destpart, srcpart))
            }
        }
    }
}
pragma solidity 0.6.6;
import { RLPReader } from "./RLPReader.sol";
library ExitPayloadReader {
  using RLPReader for bytes;
  using RLPReader for RLPReader.RLPItem;
  uint8 constant WORD_SIZE = 32;
  struct ExitPayload {
    RLPReader.RLPItem[] data;
  }
  struct Receipt {
    RLPReader.RLPItem[] data;
    bytes raw;
    uint256 logIndex;
  }
  struct Log {
    RLPReader.RLPItem data;
    RLPReader.RLPItem[] list;
  }
  struct LogTopics {
    RLPReader.RLPItem[] data;
  }
  // copy paste of private copy() from RLPReader to avoid changing of existing contracts
  function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;
        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }
            src += WORD_SIZE;
            dest += WORD_SIZE;
        }
        // left over bytes. Mask is used to remove unwanted bytes from the word
        uint mask = 256 ** (WORD_SIZE - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask)) // zero out src
            let destpart := and(mload(dest), mask) // retrieve the bytes
            mstore(dest, or(destpart, srcpart))
        }
    }
  function toExitPayload(bytes memory data)
        internal
        pure
        returns (ExitPayload memory)
    {
        RLPReader.RLPItem[] memory payloadData = data
            .toRlpItem()
            .toList();
        return ExitPayload(payloadData);
    }
    function getHeaderNumber(ExitPayload memory payload) internal pure returns(uint256) {
      return payload.data[0].toUint();
    }
    function getBlockProof(ExitPayload memory payload) internal pure returns(bytes memory) {
      return payload.data[1].toBytes();
    }
    function getBlockNumber(ExitPayload memory payload) internal pure returns(uint256) {
      return payload.data[2].toUint();
    }
    function getBlockTime(ExitPayload memory payload) internal pure returns(uint256) {
      return payload.data[3].toUint();
    }
    function getTxRoot(ExitPayload memory payload) internal pure returns(bytes32) {
      return bytes32(payload.data[4].toUint());
    }
    function getReceiptRoot(ExitPayload memory payload) internal pure returns(bytes32) {
      return bytes32(payload.data[5].toUint());
    }
    function getReceipt(ExitPayload memory payload) internal pure returns(Receipt memory receipt) {
      receipt.raw = payload.data[6].toBytes();
      RLPReader.RLPItem memory receiptItem = receipt.raw.toRlpItem();
      if (receiptItem.isList()) {
          // legacy tx
          receipt.data = receiptItem.toList();
      } else {
          // pop first byte before parsting receipt
          bytes memory typedBytes = receipt.raw;
          bytes memory result = new bytes(typedBytes.length - 1);
          uint256 srcPtr;
          uint256 destPtr;
          assembly {
              srcPtr := add(33, typedBytes)
              destPtr := add(0x20, result)
          }
          copy(srcPtr, destPtr, result.length);
          receipt.data = result.toRlpItem().toList();
      }
      receipt.logIndex = getReceiptLogIndex(payload);
      return receipt;
    }
    function getReceiptProof(ExitPayload memory payload) internal pure returns(bytes memory) {
      return payload.data[7].toBytes();
    }
    function getBranchMaskAsBytes(ExitPayload memory payload) internal pure returns(bytes memory) {
      return payload.data[8].toBytes();
    }
    function getBranchMaskAsUint(ExitPayload memory payload) internal pure returns(uint256) {
      return payload.data[8].toUint();
    }
    function getReceiptLogIndex(ExitPayload memory payload) internal pure returns(uint256) {
      return payload.data[9].toUint();
    }
    
    // Receipt methods
    function toBytes(Receipt memory receipt) internal pure returns(bytes memory) {
        return receipt.raw;
    }
    function getLog(Receipt memory receipt) internal pure returns(Log memory) {
        RLPReader.RLPItem memory logData = receipt.data[3].toList()[receipt.logIndex];
        return Log(logData, logData.toList());
    }
    // Log methods
    function getEmitter(Log memory log) internal pure returns(address) {
      return RLPReader.toAddress(log.list[0]);
    }
    function getTopics(Log memory log) internal pure returns(LogTopics memory) {
        return LogTopics(log.list[1].toList());
    }
    function getData(Log memory log) internal pure returns(bytes memory) {
        return log.list[2].toBytes();
    }
    function toRlpBytes(Log memory log) internal pure returns(bytes memory) {
      return log.data.toRlpBytes();
    }
    // LogTopics methods
    function getField(LogTopics memory topics, uint256 index) internal pure returns(RLPReader.RLPItem memory) {
      return topics.data[index];
    }
}
/*
 * @title MerklePatriciaVerifier
 * @author Sam Mayo ([email protected])
 *
 * @dev Library for verifing merkle patricia proofs.
 */
pragma solidity 0.6.6;
import {RLPReader} from "./RLPReader.sol";
library MerklePatriciaProof {
    /*
     * @dev Verifies a merkle patricia proof.
     * @param value The terminating value in the trie.
     * @param encodedPath The path in the trie leading to value.
     * @param rlpParentNodes The rlp encoded stack of nodes.
     * @param root The root hash of the trie.
     * @return The boolean validity of the proof.
     */
    function verify(
        bytes memory value,
        bytes memory encodedPath,
        bytes memory rlpParentNodes,
        bytes32 root
    ) internal pure returns (bool) {
        RLPReader.RLPItem memory item = RLPReader.toRlpItem(rlpParentNodes);
        RLPReader.RLPItem[] memory parentNodes = RLPReader.toList(item);
        bytes memory currentNode;
        RLPReader.RLPItem[] memory currentNodeList;
        bytes32 nodeKey = root;
        uint256 pathPtr = 0;
        bytes memory path = _getNibbleArray(encodedPath);
        if (path.length == 0) {
            return false;
        }
        for (uint256 i = 0; i < parentNodes.length; i++) {
            if (pathPtr > path.length) {
                return false;
            }
            currentNode = RLPReader.toRlpBytes(parentNodes[i]);
            if (nodeKey != keccak256(currentNode)) {
                return false;
            }
            currentNodeList = RLPReader.toList(parentNodes[i]);
            if (currentNodeList.length == 17) {
                if (pathPtr == path.length) {
                    if (
                        keccak256(RLPReader.toBytes(currentNodeList[16])) ==
                        keccak256(value)
                    ) {
                        return true;
                    } else {
                        return false;
                    }
                }
                uint8 nextPathNibble = uint8(path[pathPtr]);
                if (nextPathNibble > 16) {
                    return false;
                }
                nodeKey = bytes32(
                    RLPReader.toUintStrict(currentNodeList[nextPathNibble])
                );
                pathPtr += 1;
            } else if (currentNodeList.length == 2) {
                bytes memory nodeValue = RLPReader.toBytes(currentNodeList[0]);
                uint256 traversed = _nibblesToTraverse(
                    nodeValue,
                    path,
                    pathPtr
                );
                //enforce correct nibble
                bytes1 prefix = _getNthNibbleOfBytes(0, nodeValue);
                if (pathPtr + traversed == path.length) {
                    //leaf node
                    if (
                        keccak256(RLPReader.toBytes(currentNodeList[1])) == keccak256(value) && 
                        (prefix == bytes1(uint8(2)) || prefix == bytes1(uint8(3)))
                    ) {
                        return true;
                    } else {
                        return false;
                    }
                }
                //extension node
                if (traversed == 0 || (prefix != bytes1(uint8(0)) && prefix != bytes1(uint8(1)))) {
                    return false;
                }
                pathPtr += traversed;
                nodeKey = bytes32(RLPReader.toUintStrict(currentNodeList[1]));
            } else {
                return false;
            }
        }
        return false; // default
    }
    function _nibblesToTraverse(
        bytes memory encodedPartialPath,
        bytes memory path,
        uint256 pathPtr
    ) private pure returns (uint256) {
        uint256 len = 0;
        // encodedPartialPath has elements that are each two hex characters (1 byte), but partialPath
        // and slicedPath have elements that are each one hex character (1 nibble)
        bytes memory partialPath = _getNibbleArray(encodedPartialPath);
        bytes memory slicedPath = new bytes(partialPath.length);
        // pathPtr counts nibbles in path
        // partialPath.length is a number of nibbles
        for (uint256 i = pathPtr; i < pathPtr + partialPath.length; i++) {
            bytes1 pathNibble = path[i];
            slicedPath[i - pathPtr] = pathNibble;
        }
        if (keccak256(partialPath) == keccak256(slicedPath)) {
            len = partialPath.length;
        } else {
            len = 0;
        }
        return len;
    }
    // bytes b must be hp encoded
    function _getNibbleArray(bytes memory b)
        internal
        pure
        returns (bytes memory)
    {
        bytes memory nibbles = "";
        if (b.length > 0) {
            uint8 offset;
            uint8 hpNibble = uint8(_getNthNibbleOfBytes(0, b));
            if (hpNibble == 1 || hpNibble == 3) {
                nibbles = new bytes(b.length * 2 - 1);
                bytes1 oddNibble = _getNthNibbleOfBytes(1, b);
                nibbles[0] = oddNibble;
                offset = 1;
            } else {
                nibbles = new bytes(b.length * 2 - 2);
                offset = 0;
            }
            for (uint256 i = offset; i < nibbles.length; i++) {
                nibbles[i] = _getNthNibbleOfBytes(i - offset + 2, b);
            }
        }
        return nibbles;
    }
    function _getNthNibbleOfBytes(uint256 n, bytes memory str)
        private
        pure
        returns (bytes1)
    {
        return
            bytes1(
                n % 2 == 0 ? uint8(str[n / 2]) / 0x10 : uint8(str[n / 2]) % 0x10
            );
    }
}
pragma solidity 0.6.6;
library Merkle {
    function checkMembership(
        bytes32 leaf,
        uint256 index,
        bytes32 rootHash,
        bytes memory proof
    ) internal pure returns (bool) {
        require(proof.length % 32 == 0, "Invalid proof length");
        uint256 proofHeight = proof.length / 32;
        // Proof of size n means, height of the tree is n+1.
        // In a tree of height n+1, max #leafs possible is 2 ^ n
        require(index < 2 ** proofHeight, "Leaf index is too big");
        bytes32 proofElement;
        bytes32 computedHash = leaf;
        for (uint256 i = 32; i <= proof.length; i += 32) {
            assembly {
                proofElement := mload(add(proof, i))
            }
            if (index % 2 == 0) {
                computedHash = keccak256(
                    abi.encodePacked(computedHash, proofElement)
                );
            } else {
                computedHash = keccak256(
                    abi.encodePacked(proofElement, computedHash)
                );
            }
            index = index / 2;
        }
        return computedHash == rootHash;
    }
}
pragma solidity 0.6.6;
import {RLPReader} from "../../lib/RLPReader.sol";
/// @title Token predicate interface for all pos portal predicates
/// @notice Abstract interface that defines methods for custom predicates
interface ITokenPredicate {
    /**
     * @notice Deposit tokens into pos portal
     * @dev When `depositor` deposits tokens into pos portal, tokens get locked into predicate contract.
     * @param depositor Address who wants to deposit tokens
     * @param depositReceiver Address (address) who wants to receive tokens on side chain
     * @param rootToken Token which gets deposited
     * @param depositData Extra data for deposit (amount for ERC20, token id for ERC721 etc.) [ABI encoded]
     */
    function lockTokens(
        address depositor,
        address depositReceiver,
        address rootToken,
        bytes calldata depositData
    ) external;
    /**
     * @notice Validates and processes exit while withdraw process
     * @dev Validates exit log emitted on sidechain. Reverts if validation fails.
     * @dev Processes withdraw based on custom logic. Example: transfer ERC20/ERC721, mint ERC721 if mintable withdraw
     * @param sender unused for polygon predicates, being kept for abi compatability
     * @param rootToken Token which gets withdrawn
     * @param logRLPList Valid sidechain log for data like amount, token id etc.
     */
    function exitTokens(
        address sender,
        address rootToken,
        bytes calldata logRLPList
    ) external;
}
pragma solidity 0.6.6;
contract Initializable {
    bool inited = false;
    modifier initializer() {
        require(!inited, "already inited");
        _;
        inited = true;
    }
    function _disableInitializer() internal {
        inited = true;
    }
}
pragma solidity 0.6.6;
/**
 * @notice DISCLAIMER:
 * Do not use NativeMetaTransaction and ContextMixin together with OpenZeppelin's "multicall"
 * nor any other form of self delegatecall!
 * Risk of address spoofing attacks.
 * Read more: https://blog.openzeppelin.com/arbitrary-address-spoofing-vulnerability-erc2771context-multicall-public-disclosure
 */
import {SafeMath} from "@openzeppelin/contracts/math/SafeMath.sol";
import {EIP712Base} from "./EIP712Base.sol";
contract NativeMetaTransaction is EIP712Base {
    using SafeMath for uint256;
    bytes32 private constant META_TRANSACTION_TYPEHASH = keccak256(
        bytes(
            "MetaTransaction(uint256 nonce,address from,bytes functionSignature)"
        )
    );
    event MetaTransactionExecuted(
        address indexed userAddress,
        address payable indexed relayerAddress,
        bytes functionSignature
    );
    mapping(address => uint256) nonces;
    /*
     * Meta transaction structure.
     * No point of including value field here as if user is doing value transfer then he has the funds to pay for gas
     * He should call the desired function directly in that case.
     */
    struct MetaTransaction {
        uint256 nonce;
        address from;
        bytes functionSignature;
    }
    function executeMetaTransaction(
        address userAddress,
        bytes calldata functionSignature,
        bytes32 sigR,
        bytes32 sigS,
        uint8 sigV
    ) external payable returns (bytes memory) {
        MetaTransaction memory metaTx = MetaTransaction({
            nonce: nonces[userAddress],
            from: userAddress,
            functionSignature: functionSignature
        });
        require(
            verify(userAddress, metaTx, sigR, sigS, sigV),
            "Signer and signature do not match"
        );
        // increase nonce for user (to avoid re-use)
        ++nonces[userAddress];
        emit MetaTransactionExecuted(
            userAddress,
            msg.sender,
            functionSignature
        );
        // Append userAddress and relayer address at the end to extract it from calling context
        (bool success, bytes memory returnData) = address(this).call(
            abi.encodePacked(functionSignature, userAddress)
        );
        require(success, "Function call not successful");
        return returnData;
    }
    function getNonce(address user) external view returns (uint256 nonce) {
        nonce = nonces[user];
    }
    function hashMetaTransaction(MetaTransaction memory metaTx)
        internal
        pure
        returns (bytes32)
    {
        return
            keccak256(
                abi.encode(
                    META_TRANSACTION_TYPEHASH,
                    metaTx.nonce,
                    metaTx.from,
                    keccak256(metaTx.functionSignature)
                )
            );
    }
    function verify(
        address signer,
        MetaTransaction memory metaTx,
        bytes32 sigR,
        bytes32 sigS,
        uint8 sigV
    ) internal view returns (bool) {
        require(signer != address(0), "NativeMetaTransaction: INVALID_SIGNER");
        return
            signer ==
            ecrecover(
                toTypedMessageHash(hashMetaTransaction(metaTx)),
                sigV,
                sigR,
                sigS
            );
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "../utils/EnumerableSet.sol";
import "../utils/Address.sol";
import "../GSN/Context.sol";
/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;
    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }
    mapping (bytes32 => RoleData) private _roles;
    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }
    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");
        _grantRole(role, account);
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");
        _revokeRole(role, account);
    }
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");
        _revokeRole(role, account);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }
    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
        _roles[role].adminRole = adminRole;
    }
    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }
    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}
pragma solidity 0.6.6;
import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
contract AccessControlMixin is AccessControl {
    string private _revertMsg;
    function _setupContractId(string memory contractId) internal {
        _revertMsg = string(abi.encodePacked(contractId, ": INSUFFICIENT_PERMISSIONS"));
    }
    modifier only(bytes32 role) {
        require(
            hasRole(role, _msgSender()),
            _revertMsg
        );
        _;
    }
}
pragma solidity 0.6.6;
/**
 * @notice DISCLAIMER:
 * Do not use NativeMetaTransaction and ContextMixin together with OpenZeppelin's "multicall"
 * nor any other form of self delegatecall!
 * Risk of address spoofing attacks.
 * Read more: https://blog.openzeppelin.com/arbitrary-address-spoofing-vulnerability-erc2771context-multicall-public-disclosure
 */
abstract contract ContextMixin {
    function msgSender()
        internal
        view
        returns (address payable sender)
    {
        if (msg.sender == address(this)) {
            bytes memory array = msg.data;
            uint256 index = msg.data.length;
            assembly {
                // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those.
                sender := and(
                    mload(add(array, index)),
                    0xffffffffffffffffffffffffffffffffffffffff
                )
            }
        } else {
            sender = msg.sender;
        }
        return sender;
    }
}
pragma solidity 0.6.6;
import {Initializable} from "./Initializable.sol";
contract EIP712Base is Initializable {
    struct EIP712Domain {
        string name;
        string version;
        address verifyingContract;
        bytes32 salt;
    }
    string constant public ERC712_VERSION = "1";
    bytes32 internal constant EIP712_DOMAIN_TYPEHASH = keccak256(
        bytes(
            "EIP712Domain(string name,string version,address verifyingContract,bytes32 salt)"
        )
    );
    bytes32 internal domainSeperator;
    // supposed to be called once while initializing.
    // one of the contractsa that inherits this contract follows proxy pattern
    // so it is not possible to do this in a constructor
    function _initializeEIP712(
        string memory name
    )
        internal
        initializer
    {
        _setDomainSeperator(name);
    }
    function _setDomainSeperator(string memory name) internal {
        domainSeperator = keccak256(
            abi.encode(
                EIP712_DOMAIN_TYPEHASH,
                keccak256(bytes(name)),
                keccak256(bytes(ERC712_VERSION)),
                address(this),
                bytes32(getChainId())
            )
        );
    }
    function getDomainSeperator() public view returns (bytes32) {
        return domainSeperator;
    }
    function getChainId() public pure returns (uint256) {
        uint256 id;
        assembly {
            id := chainid()
        }
        return id;
    }
    /**
     * Accept message hash and returns hash message in EIP712 compatible form
     * So that it can be used to recover signer from signature signed using EIP712 formatted data
     * https://eips.ethereum.org/EIPS/eip-712
     * "\\\\x19" makes the encoding deterministic
     * "\\\\x01" is the version byte to make it compatible to EIP-191
     */
    function toTypedMessageHash(bytes32 messageHash)
        internal
        view
        returns (bytes32)
    {
        return
            keccak256(
                abi.encodePacked("\\x19\\x01", getDomainSeperator(), messageHash)
            );
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.0.0, only sets of type `address` (`AddressSet`) and `uint256`
 * (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.
    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];
        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.
            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;
            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.
            bytes32 lastvalue = set._values[lastIndex];
            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based
            // Delete the slot where the moved value was stored
            set._values.pop();
            // Delete the index for the deleted slot
            delete set._indexes[value];
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }
   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }
    // AddressSet
    struct AddressSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(value)));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(value)));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(value)));
    }
    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint256(_at(set._inner, index)));
    }
    // UintSet
    struct UintSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.2;
/**
 * @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) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }
    /**
     * @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");
        return _functionCallWithValue(target, data, value, errorMessage);
    }
    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        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);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/*
 * @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;
    }
}

pragma solidity 0.6.6;
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import {AccessControlMixin} from "../../common/AccessControlMixin.sol";
import {RLPReader} from "../../lib/RLPReader.sol";
import {ITokenPredicate} from "./ITokenPredicate.sol";
import {Initializable} from "../../common/Initializable.sol";
contract ERC20Predicate is ITokenPredicate, AccessControlMixin, Initializable {
    using RLPReader for bytes;
    using RLPReader for RLPReader.RLPItem;
    using SafeERC20 for IERC20;
    bytes32 public constant MANAGER_ROLE = keccak256("MANAGER_ROLE");
    bytes32 public constant TOKEN_TYPE = keccak256("ERC20");
    bytes32 public constant TRANSFER_EVENT_SIG = 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;
    event LockedERC20(
        address indexed depositor,
        address indexed depositReceiver,
        address indexed rootToken,
        uint256 amount
    );
    event ExitedERC20(
        address indexed exitor,
        address indexed rootToken,
        uint256 amount
    );
    constructor() public {
        // Disable initializer on implementation contract
        _disableInitializer();
    }
    function initialize(address _owner) external initializer {
        _setupContractId("ERC20Predicate");
        _setupRole(DEFAULT_ADMIN_ROLE, _owner);
        _setupRole(MANAGER_ROLE, _owner);
    }
    /**
     * @notice Lock ERC20 tokens for deposit, callable only by manager
     * @param depositor Address who wants to deposit tokens
     * @param depositReceiver Address (address) who wants to receive tokens on child chain
     * @param rootToken Token which gets deposited
     * @param depositData ABI encoded amount
     */
    function lockTokens(
        address depositor,
        address depositReceiver,
        address rootToken,
        bytes calldata depositData
    )
        external
        override
        only(MANAGER_ROLE)
    {
        uint256 amount = abi.decode(depositData, (uint256));
        emit LockedERC20(depositor, depositReceiver, rootToken, amount);
        IERC20(rootToken).safeTransferFrom(depositor, address(this), amount);
    }
    /**
     * @notice Validates log signature, from and to address
     * then sends the correct amount to withdrawer
     * callable only by manager
     * @notice address unused, being kept for abi compatability
     * @param rootToken Token which gets withdrawn
     * @param log Valid ERC20 burn log from child chain
     */
    function exitTokens(
        address,
        address rootToken,
        bytes calldata log
    )
        external
        override
        only(MANAGER_ROLE)
    {
        RLPReader.RLPItem[] memory logRLPList = log.toRlpItem().toList();
        RLPReader.RLPItem[] memory logTopicRLPList = logRLPList[1].toList(); // topics
        require(
            bytes32(logTopicRLPList[0].toUint()) == TRANSFER_EVENT_SIG, // topic0 is event sig
            "ERC20Predicate: INVALID_SIGNATURE"
        );
        address withdrawer = address(logTopicRLPList[1].toUint()); // topic1 is from address
        require(
            address(logTopicRLPList[2].toUint()) == address(0), // topic2 is to address
            "ERC20Predicate: INVALID_RECEIVER"
        );
        uint256 amount = logRLPList[2].toUint(); // log data field is the amount
        IERC20(rootToken).safeTransfer(
            withdrawer,
            amount
        );
        emit ExitedERC20(withdrawer, rootToken, amount);
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
 * @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);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
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");
        }
    }
}
pragma solidity 0.6.6;
import {AccessControl} from "@openzeppelin/contracts/access/AccessControl.sol";
contract AccessControlMixin is AccessControl {
    string private _revertMsg;
    function _setupContractId(string memory contractId) internal {
        _revertMsg = string(abi.encodePacked(contractId, ": INSUFFICIENT_PERMISSIONS"));
    }
    modifier only(bytes32 role) {
        require(
            hasRole(role, _msgSender()),
            _revertMsg
        );
        _;
    }
}
/*
 * @author Hamdi Allam [email protected]
 * Please reach out with any questions or concerns
 * https://github.com/hamdiallam/Solidity-RLP/blob/e681e25a376dbd5426b509380bc03446f05d0f97/contracts/RLPReader.sol
 */
pragma solidity 0.6.6;
library RLPReader {
    uint8 constant STRING_SHORT_START = 0x80;
    uint8 constant STRING_LONG_START  = 0xb8;
    uint8 constant LIST_SHORT_START   = 0xc0;
    uint8 constant LIST_LONG_START    = 0xf8;
    uint8 constant WORD_SIZE = 32;
    struct RLPItem {
        uint len;
        uint memPtr;
    }
    struct Iterator {
        RLPItem item;   // Item that's being iterated over.
        uint nextPtr;   // Position of the next item in the list.
    }
    /*
    * @dev Returns the next element in the iteration. Reverts if it has not next element.
    * @param self The iterator.
    * @return The next element in the iteration.
    */
    function next(Iterator memory self) internal pure returns (RLPItem memory) {
        require(hasNext(self));
        uint ptr = self.nextPtr;
        uint itemLength = _itemLength(ptr);
        self.nextPtr = ptr + itemLength;
        return RLPItem(itemLength, ptr);
    }
    /*
    * @dev Returns true if the iteration has more elements.
    * @param self The iterator.
    * @return true if the iteration has more elements.
    */
    function hasNext(Iterator memory self) internal pure returns (bool) {
        RLPItem memory item = self.item;
        return self.nextPtr < item.memPtr + item.len;
    }
    /*
    * @param item RLP encoded bytes
    */
    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
        uint memPtr;
        assembly {
            memPtr := add(item, 0x20)
        }
        return RLPItem(item.length, memPtr);
    }
    /*
    * @dev Create an iterator. Reverts if item is not a list.
    * @param self The RLP item.
    * @return An 'Iterator' over the item.
    */
    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
        require(isList(self));
        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }
    /*
    * @param the RLP item.
    */
    function rlpLen(RLPItem memory item) internal pure returns (uint) {
        return item.len;
    }
    /*
     * @param the RLP item.
     * @return (memPtr, len) pair: location of the item's payload in memory.
     */
    function payloadLocation(RLPItem memory item) internal pure returns (uint, uint) {
        uint offset = _payloadOffset(item.memPtr);
        uint memPtr = item.memPtr + offset;
        uint len = item.len - offset; // data length
        return (memPtr, len);
    }
    /*
    * @param the RLP item.
    */
    function payloadLen(RLPItem memory item) internal pure returns (uint) {
        (, uint len) = payloadLocation(item);
        return len;
    }
    /*
    * @param the RLP item containing the encoded list.
    */
    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
        require(isList(item));
        uint items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);
        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint dataLen;
        for (uint i = 0; i < items; i++) {
            dataLen = _itemLength(memPtr);
            result[i] = RLPItem(dataLen, memPtr); 
            memPtr = memPtr + dataLen;
        }
        require(memPtr - item.memPtr == item.len, "Wrong total length.");
        return result;
    }
    // @return indicator whether encoded payload is a list. negate this function call for isData.
    function isList(RLPItem memory item) internal pure returns (bool) {
        if (item.len == 0) return false;
        uint8 byte0;
        uint memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }
        if (byte0 < LIST_SHORT_START)
            return false;
        return true;
    }
    /*
     * @dev A cheaper version of keccak256(toRlpBytes(item)) that avoids copying memory.
     * @return keccak256 hash of RLP encoded bytes.
     */
    function rlpBytesKeccak256(RLPItem memory item) internal pure returns (bytes32) {
        uint256 ptr = item.memPtr;
        uint256 len = item.len;
        bytes32 result;
        assembly {
            result := keccak256(ptr, len)
        }
        return result;
    }
    /*
     * @dev A cheaper version of keccak256(toBytes(item)) that avoids copying memory.
     * @return keccak256 hash of the item payload.
     */
    function payloadKeccak256(RLPItem memory item) internal pure returns (bytes32) {
        (uint memPtr, uint len) = payloadLocation(item);
        bytes32 result;
        assembly {
            result := keccak256(memPtr, len)
        }
        return result;
    }
    /** RLPItem conversions into data types **/
    // @returns raw rlp encoding in bytes
    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
        bytes memory result = new bytes(item.len);
        if (result.length == 0) return result;
        
        uint ptr;
        assembly {
            ptr := add(0x20, result)
        }
        copy(item.memPtr, ptr, item.len);
        return result;
    }
    // any non-zero byte except "0x80" is considered true
    function toBoolean(RLPItem memory item) internal pure returns (bool) {
        require(item.len == 1);
        uint result;
        uint memPtr = item.memPtr;
        assembly {
            result := byte(0, mload(memPtr))
        }
        // SEE Github Issue #5.
        // Summary: Most commonly used RLP libraries (i.e Geth) will encode
        // "0" as "0x80" instead of as "0". We handle this edge case explicitly
        // here.
        if (result == 0 || result == STRING_SHORT_START) {
            return false;
        } else {
            return true;
        }
    }
    function toAddress(RLPItem memory item) internal pure returns (address) {
        // 1 byte for the length prefix
        require(item.len == 21);
        return address(toUint(item));
    }
    function toUint(RLPItem memory item) internal pure returns (uint) {
        require(item.len > 0 && item.len <= 33);
        (uint memPtr, uint len) = payloadLocation(item);
        uint result;
        assembly {
            result := mload(memPtr)
            // shfit to the correct location if neccesary
            if lt(len, 32) {
                result := div(result, exp(256, sub(32, len)))
            }
        }
        return result;
    }
    // enforces 32 byte length
    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
        // one byte prefix
        require(item.len == 33);
        uint result;
        uint memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }
        return result;
    }
    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
        require(item.len > 0);
        (uint memPtr, uint len) = payloadLocation(item);
        bytes memory result = new bytes(len);
        uint destPtr;
        assembly {
            destPtr := add(0x20, result)
        }
        copy(memPtr, destPtr, len);
        return result;
    }
    /*
    * Private Helpers
    */
    // @return number of payload items inside an encoded list.
    function numItems(RLPItem memory item) private pure returns (uint) {
        if (item.len == 0) return 0;
        uint count = 0;
        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint endPtr = item.memPtr + item.len;
        while (currPtr < endPtr) {
           currPtr = currPtr + _itemLength(currPtr); // skip over an item
           count++;
        }
        return count;
    }
    // @return entire rlp item byte length
    function _itemLength(uint memPtr) private pure returns (uint) {
        uint itemLen;
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }
        if (byte0 < STRING_SHORT_START)
            itemLen = 1;
        
        else if (byte0 < STRING_LONG_START)
            itemLen = byte0 - STRING_SHORT_START + 1;
        else if (byte0 < LIST_SHORT_START) {
            assembly {
                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
                memPtr := add(memPtr, 1) // skip over the first byte
                
                /* 32 byte word size */
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }
        else if (byte0 < LIST_LONG_START) {
            itemLen = byte0 - LIST_SHORT_START + 1;
        } 
        else {
            assembly {
                let byteLen := sub(byte0, 0xf7)
                memPtr := add(memPtr, 1)
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }
        return itemLen;
    }
    // @return number of bytes until the data
    function _payloadOffset(uint memPtr) private pure returns (uint) {
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }
        if (byte0 < STRING_SHORT_START) 
            return 0;
        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
            return 1;
        else if (byte0 < LIST_SHORT_START)  // being explicit
            return byte0 - (STRING_LONG_START - 1) + 1;
        else
            return byte0 - (LIST_LONG_START - 1) + 1;
    }
    /*
    * @param src Pointer to source
    * @param dest Pointer to destination
    * @param len Amount of memory to copy from the source
    */
    function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;
        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }
            src += WORD_SIZE;
            dest += WORD_SIZE;
        }
        if (len > 0) {
            // left over bytes. Mask is used to remove unwanted bytes from the word
            uint mask = 256 ** (WORD_SIZE - len) - 1;
            assembly {
                let srcpart := and(mload(src), not(mask)) // zero out src
                let destpart := and(mload(dest), mask) // retrieve the bytes
                mstore(dest, or(destpart, srcpart))
            }
        }
    }
}
pragma solidity 0.6.6;
import {RLPReader} from "../../lib/RLPReader.sol";
/// @title Token predicate interface for all pos portal predicates
/// @notice Abstract interface that defines methods for custom predicates
interface ITokenPredicate {
    /**
     * @notice Deposit tokens into pos portal
     * @dev When `depositor` deposits tokens into pos portal, tokens get locked into predicate contract.
     * @param depositor Address who wants to deposit tokens
     * @param depositReceiver Address (address) who wants to receive tokens on side chain
     * @param rootToken Token which gets deposited
     * @param depositData Extra data for deposit (amount for ERC20, token id for ERC721 etc.) [ABI encoded]
     */
    function lockTokens(
        address depositor,
        address depositReceiver,
        address rootToken,
        bytes calldata depositData
    ) external;
    /**
     * @notice Validates and processes exit while withdraw process
     * @dev Validates exit log emitted on sidechain. Reverts if validation fails.
     * @dev Processes withdraw based on custom logic. Example: transfer ERC20/ERC721, mint ERC721 if mintable withdraw
     * @param sender unused for polygon predicates, being kept for abi compatability
     * @param rootToken Token which gets withdrawn
     * @param logRLPList Valid sidechain log for data like amount, token id etc.
     */
    function exitTokens(
        address sender,
        address rootToken,
        bytes calldata logRLPList
    ) external;
}
pragma solidity 0.6.6;
contract Initializable {
    bool inited = false;
    modifier initializer() {
        require(!inited, "already inited");
        _;
        inited = true;
    }
    function _disableInitializer() internal {
        inited = true;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
 * @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, 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) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * 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);
        uint256 c = a - b;
        return c;
    }
    /**
     * @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) {
        // 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 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts 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) {
        return div(a, b, "SafeMath: division by zero");
    }
    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts 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) {
        return mod(a, b, "SafeMath: modulo by zero");
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.2;
/**
 * @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) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }
    /**
     * @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");
        return _functionCallWithValue(target, data, value, errorMessage);
    }
    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        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);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "../utils/EnumerableSet.sol";
import "../utils/Address.sol";
import "../GSN/Context.sol";
/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;
    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }
    mapping (bytes32 => RoleData) private _roles;
    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }
    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");
        _grantRole(role, account);
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");
        _revokeRole(role, account);
    }
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");
        _revokeRole(role, account);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }
    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
        _roles[role].adminRole = adminRole;
    }
    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }
    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.0.0, only sets of type `address` (`AddressSet`) and `uint256`
 * (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.
    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];
        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.
            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;
            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.
            bytes32 lastvalue = set._values[lastIndex];
            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based
            // Delete the slot where the moved value was stored
            set._values.pop();
            // Delete the index for the deleted slot
            delete set._indexes[value];
            return true;
        } else {
            return false;
        }
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }
   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }
    // AddressSet
    struct AddressSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(value)));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(value)));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(value)));
    }
    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint256(_at(set._inner, index)));
    }
    // UintSet
    struct UintSet {
        Set _inner;
    }
    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }
    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }
    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }
    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }
   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/*
 * @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;
    }
}