ETH Price: $4,685.18 (+6.32%)

Transaction Decoder

Block:
23130013 at Aug-13-2025 05:23:35 AM +UTC
Transaction Fee:
0.000146065528665483 ETH $0.68
Gas Used:
244,307 Gas / 0.597876969 Gwei

Emitted Events:

167 RocketTokenRETH.Transfer( from=ERC20PredicateProxy, to=[Sender] 0xc58b1934697879c122d53fdb26a3a604292e993b, value=10000000000000000 )
168 ERC20PredicateProxy.0xbb61bd1b26b3684c7c028ff1a8f6dabcac2fac8ac57b66fa6b1efb6edeab03c4( 0xbb61bd1b26b3684c7c028ff1a8f6dabcac2fac8ac57b66fa6b1efb6edeab03c4, 0x000000000000000000000000c58b1934697879c122d53fdb26a3a604292e993b, 0x000000000000000000000000ae78736cd615f374d3085123a210448e74fc6393, 000000000000000000000000000000000000000000000000002386f26fc10000 )

Account State Difference:

  Address   Before After State Difference Code
5.591626251219934959 Eth5.591626288843212959 Eth0.000000037623278
0xA0c68C63...1bFc77C77
(Polygon (Matic): Bridge)
0xae78736C...E74Fc6393
0xc58b1934...4292e993b
0.001472801259729002 Eth
Nonce: 35
0.001326735731063519 Eth
Nonce: 36
0.000146065528665483

Execution Trace

RootChainManagerProxy.3805550f( )
  • RootChainManager.exit( inputData=0xF90AA884338EB330B90120F31875E7AB62896FEE1FB97D22F5D808C71359459DB3748ED361F2851AF926399EB622157E83D360AE5549B413167F40057300F78C1C2419564C645285FDDB36663CD09AD8E51F7426B5DA6310A41AE4D05BD35E85AFF8EBF900891FAA13D74DC2C5BBA19E912FF90F21D1105C9AAAA0D3B13006635DE7E2F87F8E79B1BEBF1ACC0356DF45A9C71627F5DFF8EAF289C642327A9A3C3BE5C374062B92D28CE7888E41CDD2B909513219668B244F07456AC437C7104D42D3E74149F45523D763BB5E37999C9944140E42A9741F46E45B013F7F4490B82C99B949B7E66705825DF381C97C7FD3A7EE99FC1A0B6E47A894E54240DEEA971ED43348F6BA9C9D79232A910E270B6C9ED72BB7E967A2D58F392DF2C9CB0B09B7A00CC67AAD5FB909C07584047A62FF84689BB87DA09B17D3AB264CAF1E628F7B2855467CE08E5560EBF5BB1D3609F07BA790A76896A0728D2195314FB4E1E623F690800088D357AC0837ED568C5EEBD247810022851EB902EC02F902E80183222C6FB9010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000800000000000008000000000000000000000010000000000000000000000000008000000800000000000000000000120000000000000000000020000000000000000000800000000000000000080000010000000000000000000000000000000000080000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000004000000002004000080001000000000000000000000000000000100000000020000000004000000000000000004000000000000000000000000000000000100000F901DDF89B940266F4F08D82372CF0FCBCCC0FF74309089C74D1F863A0DDF252AD1BE2C89B69C2B068FC378DAA952BA7F163C4A11628F55A4DF523B3EFA0000000000000000000000000C58B1934697879C122D53FDB26A3A604292E993BA00000000000000000000000000000000000000000000000000000000000000000A0000000000000000000000000000000000000000000000000002386F26FC10000F9013D940000000000000000000000000000000000001010F884A04DFE1BBBCF077DDC3E01291EEA2D5C70C2B422B415D95645B9ADCFD678CB1D63A00000000000000000000000000000000000000000000000000000000000001010A0000000000000000000000000C58B1934697879C122D53FDB26A3A604292E993BA0000000000000000000000000CE7FCB674BA27A952C71061B649FB5A5746F3B2BB8A00000000000000000000000000000000000000000000000000009D3BB48991408000000000000000000000000000000000000000000000000931036886C5916B2000000000000000000000000000000000000000000003DEFB8FE8470E439C70D000000000000000000000000000000000000000000000000930662CD23C002AA000000000000000000000000000000000000000000003DEFB908582C2CD2DB15B9063EF9063BF90131A0B3ACBA67D8FA28B4E9CA18245D76775F718CB5EFFBC698EE579D2B105D3ADF29A05E34A3C7BC6FD16D3C8ED56467F58B67E7F145EFB909B829EA84393F2F802CD3A095FFD8C1E7E6FFD75012D2167DF961F4573B40F153DAEC86FBCCBBD46E9877C4A0549338AA80BCCBC8770D5757EE88AF2E143CE20E9A9E3CD9072ADDC5E0FFB162A0E7A7271CE6FC4D62F94833D974300AA3D9DE4DEB5809467945DB36470AC2DBC9A0388920512BCE6131D07B2F8532649B8F70C5341F5C0D6D14AFA8F13BCF1B3DB3A08DD12BE31E3E796CB4D9B6951A7AC2B5FBBAAC37B59CE5C399A5DE7DAF1540FAA09283AA32117E800607E2E12CF8F7818F7AA9142EFA84AAE2247D04B7772CAA70A0EBEF6321500CC8E823239BB2B4190395158C7903FE464272C91F95242A9235238080808080808080F90211A0F6494C90851F8462E1EDC32C5FFB0F457C9BBE2C43375A9C575DA3E5D30C7E03A0856DFE0EDF8DD8EED8A5A850CB0F5152F39715798DA149E6D3F90819778CB3C0A0277849C62CDF0665A8D5A5DBCAC508F9A3A5C4AEC777690D4DBC3C5C098BC1C9A039E4851DABCBD4000C7BA3ED54441E69A4395DDB64856CDF88DD96E1E7442D99A0E4AA5396B47937509FDFD0D50927AFA8E42A2F46ED4A73F7C1E5F1F8F2B8E003A0FAFA6511B7C9E3DACE7AB1BF95411C1CA236F963BC004EBA2576F821E3E31362A0ECE5B7754C5EA2FB302DFE3964ED6AFA8DEAA294E31F5CA4850C507D1D3C333CA0E957F6CBF2A8418C3CC7790B551FC8FB6CB6A9F60F9203AC6C65982F2313F69BA038390E6731EB6B3608414B59F8B04B095D84C5BFAE520AE46AECB70F08A6A788A05F03B87EBAECB936E6D76669B8B654B5524B078454E260497A552A816265D98CA0F1942FFC2F5D2F29FCA1851E0306BC2B4AA3ACD4DD8AA296FE165A94A1BD8BDCA0763A990DD279E2B29F56988790F69352DB0FA853C962887066A35CE956A80D25A0D085B1E0E7EA6BAD700302C28D87133A2269E7C29B6DADA8CC3760B590833F27A01696707C1D90D26970DA725B561256F15BDA8B23179DBF5E61313A8C07AA5D81A0837E79918560CA10242362220819B1ADC750A6BE829741C454B133CAB5AABD19A0E7667CCAD38CDFDD9A8566C57152A4406F6C974CBBB6CE8760EE1255BA93AF2E80F902F020B902EC02F902E80183222C6FB9010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000800000000000008000000000000000000000010000000000000000000000000008000000800000000000000000000120000000000000000000020000000000000000000800000000000000000080000010000000000000000000000000000000000080000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000004000000002004000080001000000000000000000000000000000100000000020000000004000000000000000004000000000000000000000000000000000100000F901DDF89B940266F4F08D82372CF0FCBCCC0FF74309089C74D1F863A0DDF252AD1BE2C89B69C2B068FC378DAA952BA7F163C4A11628F55A4DF523B3EFA0000000000000000000000000C58B1934697879C122D53FDB26A3A604292E993BA00000000000000000000000000000000000000000000000000000000000000000A0000000000000000000000000000000000000000000000000002386F26FC10000F9013D940000000000000000000000000000000000001010F884A04DFE1BBBCF077DDC3E01291EEA2D5C70C2B422B415D95645B9ADCFD678CB1D63A00000000000000000000000000000000000000000000000000000000000001010A0000000000000000000000000C58B1934697879C122D53FDB26A3A604292E993BA0000000000000000000000000CE7FCB674BA27A952C71061B649FB5A5746F3B2BB8A00000000000000000000000000000000000000000000000000009D3BB48991408000000000000000000000000000000000000000000000000931036886C5916B2000000000000000000000000000000000000000000003DEFB8FE8470E439C70D000000000000000000000000000000000000000000000000930662CD23C002AA000000000000000000000000000000000000000000003DEFB908582C2CD2DB1582001580 )
    • RootChainProxy.headerBlocks( 864990000 ) => ( root=E763F47FE08F038B4232B61F1F0045CA138C7C45E879D87F8EA0602F83C9330E, start=75129510, end=75130021, createdAt=1755038291, proposer=0x9eaD03F7136Fc6b4bDb0780B00a1c14aE5A8B6d0 )
    • ERC20PredicateProxy.8274664f( )
      • ERC20Predicate.exitTokens( 0xc58b1934697879C122d53Fdb26A3a604292e993b, rootToken=0xae78736Cd615f374D3085123A210448E74Fc6393, log=0xF89B940266F4F08D82372CF0FCBCCC0FF74309089C74D1F863A0DDF252AD1BE2C89B69C2B068FC378DAA952BA7F163C4A11628F55A4DF523B3EFA0000000000000000000000000C58B1934697879C122D53FDB26A3A604292E993BA00000000000000000000000000000000000000000000000000000000000000000A0000000000000000000000000000000000000000000000000002386F26FC10000 )
        • RocketTokenRETH.transfer( recipient=0xc58b1934697879C122d53Fdb26A3a604292e993b, amount=10000000000000000 ) => ( True )
          • RocketStorage.getUint( _key=68C110853B1F327AADB0EEB9C79B63E176A6E7EF034AD8E92CAE6824905E84A7 ) => ( r=0 )
            exit[RootChainManager (ln:313)]
            File 1 of 7: RootChainManagerProxy
            // 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 2 of 7: ERC20PredicateProxy
            // 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)
                {}
            }

            File 3 of 7: RocketTokenRETH
            // SPDX-License-Identifier: MIT
            pragma solidity >=0.6.0 <0.8.0;
            /**
             * @dev Wrappers over Solidity's arithmetic operations with added overflow
             * checks.
             *
             * Arithmetic operations in Solidity wrap on overflow. This can easily result
             * in bugs, because programmers usually assume that an overflow raises an
             * error, which is the standard behavior in high level programming languages.
             * `SafeMath` restores this intuition by reverting the transaction when an
             * operation overflows.
             *
             * Using this library instead of the unchecked operations eliminates an entire
             * class of bugs, so it's recommended to use it always.
             */
            library SafeMath {
                /**
                 * @dev Returns the addition of two unsigned integers, with an overflow flag.
                 *
                 * _Available since v3.4._
                 */
                function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    uint256 c = a + b;
                    if (c < a) return (false, 0);
                    return (true, c);
                }
                /**
                 * @dev Returns the substraction of two unsigned integers, with an overflow flag.
                 *
                 * _Available since v3.4._
                 */
                function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    if (b > a) return (false, 0);
                    return (true, a - b);
                }
                /**
                 * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
                 *
                 * _Available since v3.4._
                 */
                function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                    // benefit is lost if 'b' is also tested.
                    // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                    if (a == 0) return (true, 0);
                    uint256 c = a * b;
                    if (c / a != b) return (false, 0);
                    return (true, c);
                }
                /**
                 * @dev Returns the division of two unsigned integers, with a division by zero flag.
                 *
                 * _Available since v3.4._
                 */
                function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    if (b == 0) return (false, 0);
                    return (true, a / b);
                }
                /**
                 * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
                 *
                 * _Available since v3.4._
                 */
                function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    if (b == 0) return (false, 0);
                    return (true, a % b);
                }
                /**
                 * @dev Returns the addition of two unsigned integers, reverting on
                 * overflow.
                 *
                 * Counterpart to Solidity's `+` operator.
                 *
                 * Requirements:
                 *
                 * - Addition cannot overflow.
                 */
                function add(uint256 a, uint256 b) internal pure returns (uint256) {
                    uint256 c = a + b;
                    require(c >= a, "SafeMath: addition overflow");
                    return c;
                }
                /**
                 * @dev Returns the subtraction of two unsigned integers, reverting on
                 * overflow (when the result is negative).
                 *
                 * Counterpart to Solidity's `-` operator.
                 *
                 * Requirements:
                 *
                 * - Subtraction cannot overflow.
                 */
                function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                    require(b <= a, "SafeMath: subtraction overflow");
                    return a - b;
                }
                /**
                 * @dev Returns the multiplication of two unsigned integers, reverting on
                 * overflow.
                 *
                 * Counterpart to Solidity's `*` operator.
                 *
                 * Requirements:
                 *
                 * - Multiplication cannot overflow.
                 */
                function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                    if (a == 0) return 0;
                    uint256 c = a * b;
                    require(c / a == b, "SafeMath: multiplication overflow");
                    return c;
                }
                /**
                 * @dev Returns the integer division of two unsigned integers, reverting on
                 * division by zero. The result is rounded towards zero.
                 *
                 * Counterpart to Solidity's `/` operator. Note: this function uses a
                 * `revert` opcode (which leaves remaining gas untouched) while Solidity
                 * uses an invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function div(uint256 a, uint256 b) internal pure returns (uint256) {
                    require(b > 0, "SafeMath: division by zero");
                    return a / b;
                }
                /**
                 * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                 * reverting when dividing by zero.
                 *
                 * Counterpart to Solidity's `%` operator. This function uses a `revert`
                 * opcode (which leaves remaining gas untouched) while Solidity uses an
                 * invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                    require(b > 0, "SafeMath: modulo by zero");
                    return a % b;
                }
                /**
                 * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                 * overflow (when the result is negative).
                 *
                 * CAUTION: This function is deprecated because it requires allocating memory for the error
                 * message unnecessarily. For custom revert reasons use {trySub}.
                 *
                 * Counterpart to Solidity's `-` operator.
                 *
                 * Requirements:
                 *
                 * - Subtraction cannot overflow.
                 */
                function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                    require(b <= a, errorMessage);
                    return a - b;
                }
                /**
                 * @dev Returns the integer division of two unsigned integers, reverting with custom message on
                 * division by zero. The result is rounded towards zero.
                 *
                 * CAUTION: This function is deprecated because it requires allocating memory for the error
                 * message unnecessarily. For custom revert reasons use {tryDiv}.
                 *
                 * Counterpart to Solidity's `/` operator. Note: this function uses a
                 * `revert` opcode (which leaves remaining gas untouched) while Solidity
                 * uses an invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                    require(b > 0, errorMessage);
                    return a / b;
                }
                /**
                 * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                 * reverting with custom message when dividing by zero.
                 *
                 * CAUTION: This function is deprecated because it requires allocating memory for the error
                 * message unnecessarily. For custom revert reasons use {tryMod}.
                 *
                 * Counterpart to Solidity's `%` operator. This function uses a `revert`
                 * opcode (which leaves remaining gas untouched) while Solidity uses an
                 * invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                    require(b > 0, errorMessage);
                    return a % b;
                }
            }
            // SPDX-License-Identifier: MIT
            pragma solidity >=0.6.0 <0.8.0;
            import "../../utils/Context.sol";
            import "./IERC20.sol";
            import "../../math/SafeMath.sol";
            /**
             * @dev Implementation of the {IERC20} interface.
             *
             * This implementation is agnostic to the way tokens are created. This means
             * that a supply mechanism has to be added in a derived contract using {_mint}.
             * For a generic mechanism see {ERC20PresetMinterPauser}.
             *
             * TIP: For a detailed writeup see our guide
             * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
             * to implement supply mechanisms].
             *
             * We have followed general OpenZeppelin guidelines: functions revert instead
             * of returning `false` on failure. This behavior is nonetheless conventional
             * and does not conflict with the expectations of ERC20 applications.
             *
             * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
             * This allows applications to reconstruct the allowance for all accounts just
             * by listening to said events. Other implementations of the EIP may not emit
             * these events, as it isn't required by the specification.
             *
             * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
             * functions have been added to mitigate the well-known issues around setting
             * allowances. See {IERC20-approve}.
             */
            contract ERC20 is Context, IERC20 {
                using SafeMath for uint256;
                mapping (address => uint256) private _balances;
                mapping (address => mapping (address => uint256)) private _allowances;
                uint256 private _totalSupply;
                string private _name;
                string private _symbol;
                uint8 private _decimals;
                /**
                 * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
                 * a default value of 18.
                 *
                 * To select a different value for {decimals}, use {_setupDecimals}.
                 *
                 * All three of these values are immutable: they can only be set once during
                 * construction.
                 */
                constructor (string memory name_, string memory symbol_) public {
                    _name = name_;
                    _symbol = symbol_;
                    _decimals = 18;
                }
                /**
                 * @dev Returns the name of the token.
                 */
                function name() public view virtual returns (string memory) {
                    return _name;
                }
                /**
                 * @dev Returns the symbol of the token, usually a shorter version of the
                 * name.
                 */
                function symbol() public view virtual returns (string memory) {
                    return _symbol;
                }
                /**
                 * @dev Returns the number of decimals used to get its user representation.
                 * For example, if `decimals` equals `2`, a balance of `505` tokens should
                 * be displayed to a user as `5,05` (`505 / 10 ** 2`).
                 *
                 * Tokens usually opt for a value of 18, imitating the relationship between
                 * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
                 * called.
                 *
                 * NOTE: This information is only used for _display_ purposes: it in
                 * no way affects any of the arithmetic of the contract, including
                 * {IERC20-balanceOf} and {IERC20-transfer}.
                 */
                function decimals() public view virtual returns (uint8) {
                    return _decimals;
                }
                /**
                 * @dev See {IERC20-totalSupply}.
                 */
                function totalSupply() public view virtual override returns (uint256) {
                    return _totalSupply;
                }
                /**
                 * @dev See {IERC20-balanceOf}.
                 */
                function balanceOf(address account) public view virtual override returns (uint256) {
                    return _balances[account];
                }
                /**
                 * @dev See {IERC20-transfer}.
                 *
                 * Requirements:
                 *
                 * - `recipient` cannot be the zero address.
                 * - the caller must have a balance of at least `amount`.
                 */
                function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
                    _transfer(_msgSender(), recipient, amount);
                    return true;
                }
                /**
                 * @dev See {IERC20-allowance}.
                 */
                function allowance(address owner, address spender) public view virtual override returns (uint256) {
                    return _allowances[owner][spender];
                }
                /**
                 * @dev See {IERC20-approve}.
                 *
                 * Requirements:
                 *
                 * - `spender` cannot be the zero address.
                 */
                function approve(address spender, uint256 amount) public virtual override returns (bool) {
                    _approve(_msgSender(), spender, amount);
                    return true;
                }
                /**
                 * @dev See {IERC20-transferFrom}.
                 *
                 * Emits an {Approval} event indicating the updated allowance. This is not
                 * required by the EIP. See the note at the beginning of {ERC20}.
                 *
                 * Requirements:
                 *
                 * - `sender` and `recipient` cannot be the zero address.
                 * - `sender` must have a balance of at least `amount`.
                 * - the caller must have allowance for ``sender``'s tokens of at least
                 * `amount`.
                 */
                function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
                    _transfer(sender, recipient, amount);
                    _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
                    return true;
                }
                /**
                 * @dev Atomically increases the allowance granted to `spender` by the caller.
                 *
                 * This is an alternative to {approve} that can be used as a mitigation for
                 * problems described in {IERC20-approve}.
                 *
                 * Emits an {Approval} event indicating the updated allowance.
                 *
                 * Requirements:
                 *
                 * - `spender` cannot be the zero address.
                 */
                function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
                    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
                    return true;
                }
                /**
                 * @dev Atomically decreases the allowance granted to `spender` by the caller.
                 *
                 * This is an alternative to {approve} that can be used as a mitigation for
                 * problems described in {IERC20-approve}.
                 *
                 * Emits an {Approval} event indicating the updated allowance.
                 *
                 * Requirements:
                 *
                 * - `spender` cannot be the zero address.
                 * - `spender` must have allowance for the caller of at least
                 * `subtractedValue`.
                 */
                function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
                    _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
                    return true;
                }
                /**
                 * @dev Moves tokens `amount` from `sender` to `recipient`.
                 *
                 * This is internal function is equivalent to {transfer}, and can be used to
                 * e.g. implement automatic token fees, slashing mechanisms, etc.
                 *
                 * Emits a {Transfer} event.
                 *
                 * Requirements:
                 *
                 * - `sender` cannot be the zero address.
                 * - `recipient` cannot be the zero address.
                 * - `sender` must have a balance of at least `amount`.
                 */
                function _transfer(address sender, address recipient, uint256 amount) internal virtual {
                    require(sender != address(0), "ERC20: transfer from the zero address");
                    require(recipient != address(0), "ERC20: transfer to the zero address");
                    _beforeTokenTransfer(sender, recipient, amount);
                    _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
                    _balances[recipient] = _balances[recipient].add(amount);
                    emit Transfer(sender, recipient, amount);
                }
                /** @dev Creates `amount` tokens and assigns them to `account`, increasing
                 * the total supply.
                 *
                 * Emits a {Transfer} event with `from` set to the zero address.
                 *
                 * Requirements:
                 *
                 * - `to` cannot be the zero address.
                 */
                function _mint(address account, uint256 amount) internal virtual {
                    require(account != address(0), "ERC20: mint to the zero address");
                    _beforeTokenTransfer(address(0), account, amount);
                    _totalSupply = _totalSupply.add(amount);
                    _balances[account] = _balances[account].add(amount);
                    emit Transfer(address(0), account, amount);
                }
                /**
                 * @dev Destroys `amount` tokens from `account`, reducing the
                 * total supply.
                 *
                 * Emits a {Transfer} event with `to` set to the zero address.
                 *
                 * Requirements:
                 *
                 * - `account` cannot be the zero address.
                 * - `account` must have at least `amount` tokens.
                 */
                function _burn(address account, uint256 amount) internal virtual {
                    require(account != address(0), "ERC20: burn from the zero address");
                    _beforeTokenTransfer(account, address(0), amount);
                    _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
                    _totalSupply = _totalSupply.sub(amount);
                    emit Transfer(account, address(0), amount);
                }
                /**
                 * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
                 *
                 * This internal function is equivalent to `approve`, and can be used to
                 * e.g. set automatic allowances for certain subsystems, etc.
                 *
                 * Emits an {Approval} event.
                 *
                 * Requirements:
                 *
                 * - `owner` cannot be the zero address.
                 * - `spender` cannot be the zero address.
                 */
                function _approve(address owner, address spender, uint256 amount) internal virtual {
                    require(owner != address(0), "ERC20: approve from the zero address");
                    require(spender != address(0), "ERC20: approve to the zero address");
                    _allowances[owner][spender] = amount;
                    emit Approval(owner, spender, amount);
                }
                /**
                 * @dev Sets {decimals} to a value other than the default one of 18.
                 *
                 * WARNING: This function should only be called from the constructor. Most
                 * applications that interact with token contracts will not expect
                 * {decimals} to ever change, and may work incorrectly if it does.
                 */
                function _setupDecimals(uint8 decimals_) internal virtual {
                    _decimals = decimals_;
                }
                /**
                 * @dev Hook that is called before any transfer of tokens. This includes
                 * minting and burning.
                 *
                 * Calling conditions:
                 *
                 * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
                 * will be to transferred to `to`.
                 * - when `from` is zero, `amount` tokens will be minted for `to`.
                 * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
                 * - `from` and `to` are never both zero.
                 *
                 * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
                 */
                function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
            }
            // SPDX-License-Identifier: MIT
            pragma solidity >=0.6.0 <0.8.0;
            /**
             * @dev Interface of the ERC20 standard as defined in the EIP.
             */
            interface IERC20 {
                /**
                 * @dev Returns the amount of tokens in existence.
                 */
                function totalSupply() external view returns (uint256);
                /**
                 * @dev Returns the amount of tokens owned by `account`.
                 */
                function balanceOf(address account) external view returns (uint256);
                /**
                 * @dev Moves `amount` tokens from the caller's account to `recipient`.
                 *
                 * Returns a boolean value indicating whether the operation succeeded.
                 *
                 * Emits a {Transfer} event.
                 */
                function transfer(address recipient, uint256 amount) external returns (bool);
                /**
                 * @dev Returns the remaining number of tokens that `spender` will be
                 * allowed to spend on behalf of `owner` through {transferFrom}. This is
                 * zero by default.
                 *
                 * This value changes when {approve} or {transferFrom} are called.
                 */
                function allowance(address owner, address spender) external view returns (uint256);
                /**
                 * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                 *
                 * Returns a boolean value indicating whether the operation succeeded.
                 *
                 * IMPORTANT: Beware that changing an allowance with this method brings the risk
                 * that someone may use both the old and the new allowance by unfortunate
                 * transaction ordering. One possible solution to mitigate this race
                 * condition is to first reduce the spender's allowance to 0 and set the
                 * desired value afterwards:
                 * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                 *
                 * Emits an {Approval} event.
                 */
                function approve(address spender, uint256 amount) external returns (bool);
                /**
                 * @dev Moves `amount` tokens from `sender` to `recipient` using the
                 * allowance mechanism. `amount` is then deducted from the caller's
                 * allowance.
                 *
                 * Returns a boolean value indicating whether the operation succeeded.
                 *
                 * Emits a {Transfer} event.
                 */
                function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                /**
                 * @dev Emitted when `value` tokens are moved from one account (`from`) to
                 * another (`to`).
                 *
                 * Note that `value` may be zero.
                 */
                event Transfer(address indexed from, address indexed to, uint256 value);
                /**
                 * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                 * a call to {approve}. `value` is the new allowance.
                 */
                event Approval(address indexed owner, address indexed spender, uint256 value);
            }
            // SPDX-License-Identifier: MIT
            pragma solidity >=0.6.0 <0.8.0;
            /*
             * @dev Provides information about the current execution context, including the
             * sender of the transaction and its data. While these are generally available
             * via msg.sender and msg.data, they should not be accessed in such a direct
             * manner, since when dealing with GSN meta-transactions the account sending and
             * paying for execution may not be the actual sender (as far as an application
             * is concerned).
             *
             * This contract is only required for intermediate, library-like contracts.
             */
            abstract contract Context {
                function _msgSender() internal view virtual returns (address payable) {
                    return msg.sender;
                }
                function _msgData() internal view virtual returns (bytes memory) {
                    this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
                    return msg.data;
                }
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            import "../interface/RocketStorageInterface.sol";
            /// @title Base settings / modifiers for each contract in Rocket Pool
            /// @author David Rugendyke
            abstract contract RocketBase {
                // Calculate using this as the base
                uint256 constant calcBase = 1 ether;
                // Version of the contract
                uint8 public version;
                // The main storage contract where primary persistant storage is maintained
                RocketStorageInterface rocketStorage = RocketStorageInterface(0);
                /*** Modifiers **********************************************************/
                /**
                * @dev Throws if called by any sender that doesn't match a Rocket Pool network contract
                */
                modifier onlyLatestNetworkContract() {
                    require(getBool(keccak256(abi.encodePacked("contract.exists", msg.sender))), "Invalid or outdated network contract");
                    _;
                }
                /**
                * @dev Throws if called by any sender that doesn't match one of the supplied contract or is the latest version of that contract
                */
                modifier onlyLatestContract(string memory _contractName, address _contractAddress) {
                    require(_contractAddress == getAddress(keccak256(abi.encodePacked("contract.address", _contractName))), "Invalid or outdated contract");
                    _;
                }
                /**
                * @dev Throws if called by any sender that isn't a registered node
                */
                modifier onlyRegisteredNode(address _nodeAddress) {
                    require(getBool(keccak256(abi.encodePacked("node.exists", _nodeAddress))), "Invalid node");
                    _;
                }
                /**
                * @dev Throws if called by any sender that isn't a trusted node DAO member
                */
                modifier onlyTrustedNode(address _nodeAddress) {
                    require(getBool(keccak256(abi.encodePacked("dao.trustednodes.", "member", _nodeAddress))), "Invalid trusted node");
                    _;
                }
                /**
                * @dev Throws if called by any sender that isn't a registered minipool
                */
                modifier onlyRegisteredMinipool(address _minipoolAddress) {
                    require(getBool(keccak256(abi.encodePacked("minipool.exists", _minipoolAddress))), "Invalid minipool");
                    _;
                }
                
                /**
                * @dev Throws if called by any account other than a guardian account (temporary account allowed access to settings before DAO is fully enabled)
                */
                modifier onlyGuardian() {
                    require(msg.sender == rocketStorage.getGuardian(), "Account is not a temporary guardian");
                    _;
                }
                /*** Methods **********************************************************/
                /// @dev Set the main Rocket Storage address
                constructor(RocketStorageInterface _rocketStorageAddress) {
                    // Update the contract address
                    rocketStorage = RocketStorageInterface(_rocketStorageAddress);
                }
                /// @dev Get the address of a network contract by name
                function getContractAddress(string memory _contractName) internal view returns (address) {
                    // Get the current contract address
                    address contractAddress = getAddress(keccak256(abi.encodePacked("contract.address", _contractName)));
                    // Check it
                    require(contractAddress != address(0x0), "Contract not found");
                    // Return
                    return contractAddress;
                }
                /// @dev Get the address of a network contract by name (returns address(0x0) instead of reverting if contract does not exist)
                function getContractAddressUnsafe(string memory _contractName) internal view returns (address) {
                    // Get the current contract address
                    address contractAddress = getAddress(keccak256(abi.encodePacked("contract.address", _contractName)));
                    // Return
                    return contractAddress;
                }
                /// @dev Get the name of a network contract by address
                function getContractName(address _contractAddress) internal view returns (string memory) {
                    // Get the contract name
                    string memory contractName = getString(keccak256(abi.encodePacked("contract.name", _contractAddress)));
                    // Check it
                    require(bytes(contractName).length > 0, "Contract not found");
                    // Return
                    return contractName;
                }
                /// @dev Get revert error message from a .call method
                function getRevertMsg(bytes memory _returnData) internal pure returns (string memory) {
                    // If the _res length is less than 68, then the transaction failed silently (without a revert message)
                    if (_returnData.length < 68) return "Transaction reverted silently";
                    assembly {
                        // Slice the sighash.
                        _returnData := add(_returnData, 0x04)
                    }
                    return abi.decode(_returnData, (string)); // All that remains is the revert string
                }
                /*** Rocket Storage Methods ****************************************/
                // Note: Unused helpers have been removed to keep contract sizes down
                /// @dev Storage get methods
                function getAddress(bytes32 _key) internal view returns (address) { return rocketStorage.getAddress(_key); }
                function getUint(bytes32 _key) internal view returns (uint) { return rocketStorage.getUint(_key); }
                function getString(bytes32 _key) internal view returns (string memory) { return rocketStorage.getString(_key); }
                function getBytes(bytes32 _key) internal view returns (bytes memory) { return rocketStorage.getBytes(_key); }
                function getBool(bytes32 _key) internal view returns (bool) { return rocketStorage.getBool(_key); }
                function getInt(bytes32 _key) internal view returns (int) { return rocketStorage.getInt(_key); }
                function getBytes32(bytes32 _key) internal view returns (bytes32) { return rocketStorage.getBytes32(_key); }
                /// @dev Storage set methods
                function setAddress(bytes32 _key, address _value) internal { rocketStorage.setAddress(_key, _value); }
                function setUint(bytes32 _key, uint _value) internal { rocketStorage.setUint(_key, _value); }
                function setString(bytes32 _key, string memory _value) internal { rocketStorage.setString(_key, _value); }
                function setBytes(bytes32 _key, bytes memory _value) internal { rocketStorage.setBytes(_key, _value); }
                function setBool(bytes32 _key, bool _value) internal { rocketStorage.setBool(_key, _value); }
                function setInt(bytes32 _key, int _value) internal { rocketStorage.setInt(_key, _value); }
                function setBytes32(bytes32 _key, bytes32 _value) internal { rocketStorage.setBytes32(_key, _value); }
                /// @dev Storage delete methods
                function deleteAddress(bytes32 _key) internal { rocketStorage.deleteAddress(_key); }
                function deleteUint(bytes32 _key) internal { rocketStorage.deleteUint(_key); }
                function deleteString(bytes32 _key) internal { rocketStorage.deleteString(_key); }
                function deleteBytes(bytes32 _key) internal { rocketStorage.deleteBytes(_key); }
                function deleteBool(bytes32 _key) internal { rocketStorage.deleteBool(_key); }
                function deleteInt(bytes32 _key) internal { rocketStorage.deleteInt(_key); }
                function deleteBytes32(bytes32 _key) internal { rocketStorage.deleteBytes32(_key); }
                /// @dev Storage arithmetic methods
                function addUint(bytes32 _key, uint256 _amount) internal { rocketStorage.addUint(_key, _amount); }
                function subUint(bytes32 _key, uint256 _amount) internal { rocketStorage.subUint(_key, _amount); }
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
            import "../RocketBase.sol";
            import "../../interface/deposit/RocketDepositPoolInterface.sol";
            import "../../interface/network/RocketNetworkBalancesInterface.sol";
            import "../../interface/token/RocketTokenRETHInterface.sol";
            import "../../interface/dao/protocol/settings/RocketDAOProtocolSettingsNetworkInterface.sol";
            // rETH is a tokenised stake in the Rocket Pool network
            // rETH is backed by ETH (subject to liquidity) at a variable exchange rate
            contract RocketTokenRETH is RocketBase, ERC20, RocketTokenRETHInterface {
                // Libs
                using SafeMath for uint;
                // Events
                event EtherDeposited(address indexed from, uint256 amount, uint256 time);
                event TokensMinted(address indexed to, uint256 amount, uint256 ethAmount, uint256 time);
                event TokensBurned(address indexed from, uint256 amount, uint256 ethAmount, uint256 time);
                // Construct with our token details
                constructor(RocketStorageInterface _rocketStorageAddress) RocketBase(_rocketStorageAddress) ERC20("Rocket Pool ETH", "rETH") {
                    // Version
                    version = 1;
                }
                // Receive an ETH deposit from a minipool or generous individual
                receive() external payable {
                    // Emit ether deposited event
                    emit EtherDeposited(msg.sender, msg.value, block.timestamp);
                }
                // Calculate the amount of ETH backing an amount of rETH
                function getEthValue(uint256 _rethAmount) override public view returns (uint256) {
                    // Get network balances
                    RocketNetworkBalancesInterface rocketNetworkBalances = RocketNetworkBalancesInterface(getContractAddress("rocketNetworkBalances"));
                    uint256 totalEthBalance = rocketNetworkBalances.getTotalETHBalance();
                    uint256 rethSupply = rocketNetworkBalances.getTotalRETHSupply();
                    // Use 1:1 ratio if no rETH is minted
                    if (rethSupply == 0) { return _rethAmount; }
                    // Calculate and return
                    return _rethAmount.mul(totalEthBalance).div(rethSupply);
                }
                // Calculate the amount of rETH backed by an amount of ETH
                function getRethValue(uint256 _ethAmount) override public view returns (uint256) {
                    // Get network balances
                    RocketNetworkBalancesInterface rocketNetworkBalances = RocketNetworkBalancesInterface(getContractAddress("rocketNetworkBalances"));
                    uint256 totalEthBalance = rocketNetworkBalances.getTotalETHBalance();
                    uint256 rethSupply = rocketNetworkBalances.getTotalRETHSupply();
                    // Use 1:1 ratio if no rETH is minted
                    if (rethSupply == 0) { return _ethAmount; }
                    // Check network ETH balance
                    require(totalEthBalance > 0, "Cannot calculate rETH token amount while total network balance is zero");
                    // Calculate and return
                    return _ethAmount.mul(rethSupply).div(totalEthBalance);
                }
                // Get the current ETH : rETH exchange rate
                // Returns the amount of ETH backing 1 rETH
                function getExchangeRate() override external view returns (uint256) {
                    return getEthValue(1 ether);
                }
                // Get the total amount of collateral available
                // Includes rETH contract balance & excess deposit pool balance
                function getTotalCollateral() override public view returns (uint256) {
                    RocketDepositPoolInterface rocketDepositPool = RocketDepositPoolInterface(getContractAddress("rocketDepositPool"));
                    return rocketDepositPool.getExcessBalance().add(address(this).balance);
                }
                // Get the current ETH collateral rate
                // Returns the portion of rETH backed by ETH in the contract as a fraction of 1 ether
                function getCollateralRate() override public view returns (uint256) {
                    uint256 totalEthValue = getEthValue(totalSupply());
                    if (totalEthValue == 0) { return calcBase; }
                    return calcBase.mul(address(this).balance).div(totalEthValue);
                }
                // Deposit excess ETH from deposit pool
                // Only accepts calls from the RocketDepositPool contract
                function depositExcess() override external payable onlyLatestContract("rocketDepositPool", msg.sender) {
                    // Emit ether deposited event
                    emit EtherDeposited(msg.sender, msg.value, block.timestamp);
                }
                // Mint rETH
                // Only accepts calls from the RocketDepositPool contract
                function mint(uint256 _ethAmount, address _to) override external onlyLatestContract("rocketDepositPool", msg.sender) {
                    // Get rETH amount
                    uint256 rethAmount = getRethValue(_ethAmount);
                    // Check rETH amount
                    require(rethAmount > 0, "Invalid token mint amount");
                    // Update balance & supply
                    _mint(_to, rethAmount);
                    // Emit tokens minted event
                    emit TokensMinted(_to, rethAmount, _ethAmount, block.timestamp);
                }
                // Burn rETH for ETH
                function burn(uint256 _rethAmount) override external {
                    // Check rETH amount
                    require(_rethAmount > 0, "Invalid token burn amount");
                    require(balanceOf(msg.sender) >= _rethAmount, "Insufficient rETH balance");
                    // Get ETH amount
                    uint256 ethAmount = getEthValue(_rethAmount);
                    // Get & check ETH balance
                    uint256 ethBalance = getTotalCollateral();
                    require(ethBalance >= ethAmount, "Insufficient ETH balance for exchange");
                    // Update balance & supply
                    _burn(msg.sender, _rethAmount);
                    // Withdraw ETH from deposit pool if required
                    withdrawDepositCollateral(ethAmount);
                    // Transfer ETH to sender
                    msg.sender.transfer(ethAmount);
                    // Emit tokens burned event
                    emit TokensBurned(msg.sender, _rethAmount, ethAmount, block.timestamp);
                }
                // Withdraw ETH from the deposit pool for collateral if required
                function withdrawDepositCollateral(uint256 _ethRequired) private {
                    // Check rETH contract balance
                    uint256 ethBalance = address(this).balance;
                    if (ethBalance >= _ethRequired) { return; }
                    // Withdraw
                    RocketDepositPoolInterface rocketDepositPool = RocketDepositPoolInterface(getContractAddress("rocketDepositPool"));
                    rocketDepositPool.withdrawExcessBalance(_ethRequired.sub(ethBalance));
                }
                // Sends any excess ETH from this contract to the deposit pool (as determined by target collateral rate)
                function depositExcessCollateral() external override {
                    // Load contracts
                    RocketDAOProtocolSettingsNetworkInterface rocketDAOProtocolSettingsNetwork = RocketDAOProtocolSettingsNetworkInterface(getContractAddress("rocketDAOProtocolSettingsNetwork"));
                    RocketDepositPoolInterface rocketDepositPool = RocketDepositPoolInterface(getContractAddress("rocketDepositPool"));
                    // Get collateral and target collateral rate
                    uint256 collateralRate = getCollateralRate();
                    uint256 targetCollateralRate = rocketDAOProtocolSettingsNetwork.getTargetRethCollateralRate();
                    // Check if we are in excess
                    if (collateralRate > targetCollateralRate) {
                        // Calculate our target collateral in ETH
                        uint256 targetCollateral = address(this).balance.mul(targetCollateralRate).div(collateralRate);
                        // If we have excess
                        if (address(this).balance > targetCollateral) {
                            // Send that excess to deposit pool
                            uint256 excessCollateral = address(this).balance.sub(targetCollateral);
                            rocketDepositPool.recycleExcessCollateral{value: excessCollateral}();
                        }
                    }
                }
                // This is called by the base ERC20 contract before all transfer, mint, and burns
                function _beforeTokenTransfer(address from, address, uint256) internal override {
                    // Don't run check if this is a mint transaction
                    if (from != address(0)) {
                        // Check which block the user's last deposit was
                        bytes32 key = keccak256(abi.encodePacked("user.deposit.block", from));
                        uint256 lastDepositBlock = getUint(key);
                        if (lastDepositBlock > 0) {
                            // Ensure enough blocks have passed
                            uint256 depositDelay = getUint(keccak256(abi.encodePacked(keccak256("dao.protocol.setting.network"), "network.reth.deposit.delay")));
                            uint256 blocksPassed = block.number.sub(lastDepositBlock);
                            require(blocksPassed > depositDelay, "Not enough time has passed since deposit");
                            // Clear the state as it's no longer necessary to check this until another deposit is made
                            deleteUint(key);
                        }
                    }
                }
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            interface RocketStorageInterface {
                // Deploy status
                function getDeployedStatus() external view returns (bool);
                // Guardian
                function getGuardian() external view returns(address);
                function setGuardian(address _newAddress) external;
                function confirmGuardian() external;
                // Getters
                function getAddress(bytes32 _key) external view returns (address);
                function getUint(bytes32 _key) external view returns (uint);
                function getString(bytes32 _key) external view returns (string memory);
                function getBytes(bytes32 _key) external view returns (bytes memory);
                function getBool(bytes32 _key) external view returns (bool);
                function getInt(bytes32 _key) external view returns (int);
                function getBytes32(bytes32 _key) external view returns (bytes32);
                // Setters
                function setAddress(bytes32 _key, address _value) external;
                function setUint(bytes32 _key, uint _value) external;
                function setString(bytes32 _key, string calldata _value) external;
                function setBytes(bytes32 _key, bytes calldata _value) external;
                function setBool(bytes32 _key, bool _value) external;
                function setInt(bytes32 _key, int _value) external;
                function setBytes32(bytes32 _key, bytes32 _value) external;
                // Deleters
                function deleteAddress(bytes32 _key) external;
                function deleteUint(bytes32 _key) external;
                function deleteString(bytes32 _key) external;
                function deleteBytes(bytes32 _key) external;
                function deleteBool(bytes32 _key) external;
                function deleteInt(bytes32 _key) external;
                function deleteBytes32(bytes32 _key) external;
                // Arithmetic
                function addUint(bytes32 _key, uint256 _amount) external;
                function subUint(bytes32 _key, uint256 _amount) external;
                // Protected storage
                function getNodeWithdrawalAddress(address _nodeAddress) external view returns (address);
                function getNodePendingWithdrawalAddress(address _nodeAddress) external view returns (address);
                function setWithdrawalAddress(address _nodeAddress, address _newWithdrawalAddress, bool _confirm) external;
                function confirmWithdrawalAddress(address _nodeAddress) external;
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            interface RocketDAOProtocolSettingsNetworkInterface {
                function getNodeConsensusThreshold() external view returns (uint256);
                function getSubmitBalancesEnabled() external view returns (bool);
                function getSubmitBalancesFrequency() external view returns (uint256);
                function getSubmitPricesEnabled() external view returns (bool);
                function getSubmitPricesFrequency() external view returns (uint256);
                function getMinimumNodeFee() external view returns (uint256);
                function getTargetNodeFee() external view returns (uint256);
                function getMaximumNodeFee() external view returns (uint256);
                function getNodeFeeDemandRange() external view returns (uint256);
                function getTargetRethCollateralRate() external view returns (uint256);
                function getRethDepositDelay() external view returns (uint256);
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            interface RocketDepositPoolInterface {
                function getBalance() external view returns (uint256);
                function getExcessBalance() external view returns (uint256);
                function deposit() external payable;
                function recycleDissolvedDeposit() external payable;
                function recycleExcessCollateral() external payable;
                function recycleLiquidatedStake() external payable;
                function assignDeposits() external;
                function withdrawExcessBalance(uint256 _amount) external;
                function getUserLastDepositBlock(address _address) external view returns (uint256);
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            interface RocketNetworkBalancesInterface {
                function getBalancesBlock() external view returns (uint256);
                function getLatestReportableBlock() external view returns (uint256);
                function getTotalETHBalance() external view returns (uint256);
                function getStakingETHBalance() external view returns (uint256);
                function getTotalRETHSupply() external view returns (uint256);
                function getETHUtilizationRate() external view returns (uint256);
                function submitBalances(uint256 _block, uint256 _total, uint256 _staking, uint256 _rethSupply) external;
                function executeUpdateBalances(uint256 _block, uint256 _totalEth, uint256 _stakingEth, uint256 _rethSupply) external;
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
            interface RocketTokenRETHInterface is IERC20 {
                function getEthValue(uint256 _rethAmount) external view returns (uint256);
                function getRethValue(uint256 _ethAmount) external view returns (uint256);
                function getExchangeRate() external view returns (uint256);
                function getTotalCollateral() external view returns (uint256);
                function getCollateralRate() external view returns (uint256);
                function depositExcess() external payable;
                function depositExcessCollateral() external;
                function mint(uint256 _ethAmount, address _to) external;
                function burn(uint256 _rethAmount) external;
            }
            

            File 4 of 7: RootChainManager
            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;
                }
            }
            

            File 5 of 7: RootChainProxy
            // File: contracts/common/governance/IGovernance.sol
            
            pragma solidity ^0.5.2;
            
            
            interface IGovernance {
                function update(address target, bytes calldata data) external;
            }
            
            // File: contracts/common/governance/Governable.sol
            
            pragma solidity ^0.5.2;
            
            
            contract Governable {
                IGovernance public governance;
            
                constructor(address _governance) public {
                    governance = IGovernance(_governance);
                }
            
                modifier onlyGovernance() {
                    require(msg.sender == address(governance), "Only governance contract is authorized");
                    _;
                }
            }
            
            // File: contracts/root/withdrawManager/IWithdrawManager.sol
            
            pragma solidity ^0.5.2;
            
            
            contract IWithdrawManager {
                function createExitQueue(address token) external;
            
                function verifyInclusion(
                    bytes calldata data,
                    uint8 offset,
                    bool verifyTxInclusion
                ) external view returns (uint256 age);
            
                function addExitToQueue(
                    address exitor,
                    address childToken,
                    address rootToken,
                    uint256 exitAmountOrTokenId,
                    bytes32 txHash,
                    bool isRegularExit,
                    uint256 priority
                ) external;
            
                function addInput(
                    uint256 exitId,
                    uint256 age,
                    address utxoOwner,
                    address token
                ) external;
            
                function challengeExit(
                    uint256 exitId,
                    uint256 inputId,
                    bytes calldata challengeData,
                    address adjudicatorPredicate
                ) external;
            }
            
            // File: contracts/common/Registry.sol
            
            pragma solidity ^0.5.2;
            
            
            contract Registry is Governable {
                // @todo hardcode constants
                bytes32 private constant WETH_TOKEN = keccak256("wethToken");
                bytes32 private constant DEPOSIT_MANAGER = keccak256("depositManager");
                bytes32 private constant STAKE_MANAGER = keccak256("stakeManager");
                bytes32 private constant VALIDATOR_SHARE = keccak256("validatorShare");
                bytes32 private constant WITHDRAW_MANAGER = keccak256("withdrawManager");
                bytes32 private constant CHILD_CHAIN = keccak256("childChain");
                bytes32 private constant STATE_SENDER = keccak256("stateSender");
                bytes32 private constant SLASHING_MANAGER = keccak256("slashingManager");
            
                address public erc20Predicate;
                address public erc721Predicate;
            
                mapping(bytes32 => address) public contractMap;
                mapping(address => address) public rootToChildToken;
                mapping(address => address) public childToRootToken;
                mapping(address => bool) public proofValidatorContracts;
                mapping(address => bool) public isERC721;
            
                enum Type {Invalid, ERC20, ERC721, Custom}
                struct Predicate {
                    Type _type;
                }
                mapping(address => Predicate) public predicates;
            
                event TokenMapped(address indexed rootToken, address indexed childToken);
                event ProofValidatorAdded(address indexed validator, address indexed from);
                event ProofValidatorRemoved(address indexed validator, address indexed from);
                event PredicateAdded(address indexed predicate, address indexed from);
                event PredicateRemoved(address indexed predicate, address indexed from);
                event ContractMapUpdated(bytes32 indexed key, address indexed previousContract, address indexed newContract);
            
                constructor(address _governance) public Governable(_governance) {}
            
                function updateContractMap(bytes32 _key, address _address) external onlyGovernance {
                    emit ContractMapUpdated(_key, contractMap[_key], _address);
                    contractMap[_key] = _address;
                }
            
                /**
                 * @dev Map root token to child token
                 * @param _rootToken Token address on the root chain
                 * @param _childToken Token address on the child chain
                 * @param _isERC721 Is the token being mapped ERC721
                 */
                function mapToken(
                    address _rootToken,
                    address _childToken,
                    bool _isERC721
                ) external onlyGovernance {
                    require(_rootToken != address(0x0) && _childToken != address(0x0), "INVALID_TOKEN_ADDRESS");
                    rootToChildToken[_rootToken] = _childToken;
                    childToRootToken[_childToken] = _rootToken;
                    isERC721[_rootToken] = _isERC721;
                    IWithdrawManager(contractMap[WITHDRAW_MANAGER]).createExitQueue(_rootToken);
                    emit TokenMapped(_rootToken, _childToken);
                }
            
                function addErc20Predicate(address predicate) public onlyGovernance {
                    require(predicate != address(0x0), "Can not add null address as predicate");
                    erc20Predicate = predicate;
                    addPredicate(predicate, Type.ERC20);
                }
            
                function addErc721Predicate(address predicate) public onlyGovernance {
                    erc721Predicate = predicate;
                    addPredicate(predicate, Type.ERC721);
                }
            
                function addPredicate(address predicate, Type _type) public onlyGovernance {
                    require(predicates[predicate]._type == Type.Invalid, "Predicate already added");
                    predicates[predicate]._type = _type;
                    emit PredicateAdded(predicate, msg.sender);
                }
            
                function removePredicate(address predicate) public onlyGovernance {
                    require(predicates[predicate]._type != Type.Invalid, "Predicate does not exist");
                    delete predicates[predicate];
                    emit PredicateRemoved(predicate, msg.sender);
                }
            
                function getValidatorShareAddress() public view returns (address) {
                    return contractMap[VALIDATOR_SHARE];
                }
            
                function getWethTokenAddress() public view returns (address) {
                    return contractMap[WETH_TOKEN];
                }
            
                function getDepositManagerAddress() public view returns (address) {
                    return contractMap[DEPOSIT_MANAGER];
                }
            
                function getStakeManagerAddress() public view returns (address) {
                    return contractMap[STAKE_MANAGER];
                }
            
                function getSlashingManagerAddress() public view returns (address) {
                    return contractMap[SLASHING_MANAGER];
                }
            
                function getWithdrawManagerAddress() public view returns (address) {
                    return contractMap[WITHDRAW_MANAGER];
                }
            
                function getChildChainAndStateSender() public view returns (address, address) {
                    return (contractMap[CHILD_CHAIN], contractMap[STATE_SENDER]);
                }
            
                function isTokenMapped(address _token) public view returns (bool) {
                    return rootToChildToken[_token] != address(0x0);
                }
            
                function isTokenMappedAndIsErc721(address _token) public view returns (bool) {
                    require(isTokenMapped(_token), "TOKEN_NOT_MAPPED");
                    return isERC721[_token];
                }
            
                function isTokenMappedAndGetPredicate(address _token) public view returns (address) {
                    if (isTokenMappedAndIsErc721(_token)) {
                        return erc721Predicate;
                    }
                    return erc20Predicate;
                }
            
                function isChildTokenErc721(address childToken) public view returns (bool) {
                    address rootToken = childToRootToken[childToken];
                    require(rootToken != address(0x0), "Child token is not mapped");
                    return isERC721[rootToken];
                }
            }
            
            // File: openzeppelin-solidity/contracts/ownership/Ownable.sol
            
            pragma solidity ^0.5.2;
            
            
            /**
             * @title Ownable
             * @dev The Ownable contract has an owner address, and provides basic authorization control
             * functions, this simplifies the implementation of "user permissions".
             */
            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;
                }
            }
            
            // File: contracts/common/misc/ProxyStorage.sol
            
            pragma solidity ^0.5.2;
            
            
            contract ProxyStorage is Ownable {
                address internal proxyTo;
            }
            
            // File: contracts/common/mixin/ChainIdMixin.sol
            
            pragma solidity ^0.5.2;
            
            
            contract ChainIdMixin {
                bytes public constant networkId = hex"89";
                uint256 public constant CHAINID = 137;
            }
            
            // File: contracts/root/RootChainStorage.sol
            
            pragma solidity ^0.5.2;
            
            
            contract RootChainHeader {
                event NewHeaderBlock(
                    address indexed proposer,
                    uint256 indexed headerBlockId,
                    uint256 indexed reward,
                    uint256 start,
                    uint256 end,
                    bytes32 root
                );
                // housekeeping event
                event ResetHeaderBlock(address indexed proposer, uint256 indexed headerBlockId);
                struct HeaderBlock {
                    bytes32 root;
                    uint256 start;
                    uint256 end;
                    uint256 createdAt;
                    address proposer;
                }
            }
            
            
            contract RootChainStorage is ProxyStorage, RootChainHeader, ChainIdMixin {
                bytes32 public heimdallId;
                uint8 public constant VOTE_TYPE = 2;
            
                uint16 internal constant MAX_DEPOSITS = 10000;
                uint256 public _nextHeaderBlock = MAX_DEPOSITS;
                uint256 internal _blockDepositId = 1;
                mapping(uint256 => HeaderBlock) public headerBlocks;
                Registry internal registry;
            }
            
            // File: contracts/common/misc/ERCProxy.sol
            
            /*
             * SPDX-License-Identitifer:    MIT
             */
            
            pragma solidity ^0.5.2;
            
            
            // See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-897.md
            
            interface ERCProxy {
                function proxyType() external pure returns (uint256 proxyTypeId);
            
                function implementation() external view returns (address codeAddr);
            }
            
            // File: contracts/common/misc/DelegateProxy.sol
            
            pragma solidity ^0.5.2;
            
            
            contract DelegateProxy is ERCProxy {
                function proxyType() external pure returns (uint256 proxyTypeId) {
                    // Upgradeable proxy
                    proxyTypeId = 2;
                }
            
                function implementation() external view returns (address);
            
                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)
                            }
                    }
                }
            }
            
            // File: contracts/common/misc/Proxy.sol
            
            pragma solidity ^0.5.2;
            
            
            contract Proxy is ProxyStorage, DelegateProxy {
                event ProxyUpdated(address indexed _new, address indexed _old);
                event OwnerUpdate(address _prevOwner, address _newOwner);
            
                constructor(address _proxyTo) public {
                    updateImplementation(_proxyTo);
                }
            
                function() external payable {
                    // require(currentContract != 0, "If app code has not been set yet, do not call");
                    // Todo: filter out some calls or handle in the end fallback
                    delegatedFwd(proxyTo, msg.data);
                }
            
                function implementation() external view returns (address) {
                    return proxyTo;
                }
            
                function updateImplementation(address _newProxyTo) public onlyOwner {
                    require(_newProxyTo != address(0x0), "INVALID_PROXY_ADDRESS");
                    require(isContract(_newProxyTo), "DESTINATION_ADDRESS_IS_NOT_A_CONTRACT");
                    emit ProxyUpdated(_newProxyTo, proxyTo);
                    proxyTo = _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/RootChainProxy.sol
            
            pragma solidity ^0.5.2;
            
            
            contract RootChainProxy is Proxy, RootChainStorage {
                constructor(
                    address _proxyTo,
                    address _registry,
                    string memory _heimdallId
                ) public Proxy(_proxyTo) {
                    registry = Registry(_registry);
                    heimdallId = keccak256(abi.encodePacked(_heimdallId));
                }
            }

            File 6 of 7: ERC20Predicate
            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;
                }
            }
            

            File 7 of 7: RocketStorage
            // SPDX-License-Identifier: MIT
            pragma solidity >=0.6.0 <0.8.0;
            /**
             * @dev Wrappers over Solidity's arithmetic operations with added overflow
             * checks.
             *
             * Arithmetic operations in Solidity wrap on overflow. This can easily result
             * in bugs, because programmers usually assume that an overflow raises an
             * error, which is the standard behavior in high level programming languages.
             * `SafeMath` restores this intuition by reverting the transaction when an
             * operation overflows.
             *
             * Using this library instead of the unchecked operations eliminates an entire
             * class of bugs, so it's recommended to use it always.
             */
            library SafeMath {
                /**
                 * @dev Returns the addition of two unsigned integers, with an overflow flag.
                 *
                 * _Available since v3.4._
                 */
                function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    uint256 c = a + b;
                    if (c < a) return (false, 0);
                    return (true, c);
                }
                /**
                 * @dev Returns the substraction of two unsigned integers, with an overflow flag.
                 *
                 * _Available since v3.4._
                 */
                function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    if (b > a) return (false, 0);
                    return (true, a - b);
                }
                /**
                 * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
                 *
                 * _Available since v3.4._
                 */
                function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                    // benefit is lost if 'b' is also tested.
                    // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                    if (a == 0) return (true, 0);
                    uint256 c = a * b;
                    if (c / a != b) return (false, 0);
                    return (true, c);
                }
                /**
                 * @dev Returns the division of two unsigned integers, with a division by zero flag.
                 *
                 * _Available since v3.4._
                 */
                function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    if (b == 0) return (false, 0);
                    return (true, a / b);
                }
                /**
                 * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
                 *
                 * _Available since v3.4._
                 */
                function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                    if (b == 0) return (false, 0);
                    return (true, a % b);
                }
                /**
                 * @dev Returns the addition of two unsigned integers, reverting on
                 * overflow.
                 *
                 * Counterpart to Solidity's `+` operator.
                 *
                 * Requirements:
                 *
                 * - Addition cannot overflow.
                 */
                function add(uint256 a, uint256 b) internal pure returns (uint256) {
                    uint256 c = a + b;
                    require(c >= a, "SafeMath: addition overflow");
                    return c;
                }
                /**
                 * @dev Returns the subtraction of two unsigned integers, reverting on
                 * overflow (when the result is negative).
                 *
                 * Counterpart to Solidity's `-` operator.
                 *
                 * Requirements:
                 *
                 * - Subtraction cannot overflow.
                 */
                function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                    require(b <= a, "SafeMath: subtraction overflow");
                    return a - b;
                }
                /**
                 * @dev Returns the multiplication of two unsigned integers, reverting on
                 * overflow.
                 *
                 * Counterpart to Solidity's `*` operator.
                 *
                 * Requirements:
                 *
                 * - Multiplication cannot overflow.
                 */
                function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                    if (a == 0) return 0;
                    uint256 c = a * b;
                    require(c / a == b, "SafeMath: multiplication overflow");
                    return c;
                }
                /**
                 * @dev Returns the integer division of two unsigned integers, reverting on
                 * division by zero. The result is rounded towards zero.
                 *
                 * Counterpart to Solidity's `/` operator. Note: this function uses a
                 * `revert` opcode (which leaves remaining gas untouched) while Solidity
                 * uses an invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function div(uint256 a, uint256 b) internal pure returns (uint256) {
                    require(b > 0, "SafeMath: division by zero");
                    return a / b;
                }
                /**
                 * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                 * reverting when dividing by zero.
                 *
                 * Counterpart to Solidity's `%` operator. This function uses a `revert`
                 * opcode (which leaves remaining gas untouched) while Solidity uses an
                 * invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                    require(b > 0, "SafeMath: modulo by zero");
                    return a % b;
                }
                /**
                 * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                 * overflow (when the result is negative).
                 *
                 * CAUTION: This function is deprecated because it requires allocating memory for the error
                 * message unnecessarily. For custom revert reasons use {trySub}.
                 *
                 * Counterpart to Solidity's `-` operator.
                 *
                 * Requirements:
                 *
                 * - Subtraction cannot overflow.
                 */
                function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                    require(b <= a, errorMessage);
                    return a - b;
                }
                /**
                 * @dev Returns the integer division of two unsigned integers, reverting with custom message on
                 * division by zero. The result is rounded towards zero.
                 *
                 * CAUTION: This function is deprecated because it requires allocating memory for the error
                 * message unnecessarily. For custom revert reasons use {tryDiv}.
                 *
                 * Counterpart to Solidity's `/` operator. Note: this function uses a
                 * `revert` opcode (which leaves remaining gas untouched) while Solidity
                 * uses an invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                    require(b > 0, errorMessage);
                    return a / b;
                }
                /**
                 * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                 * reverting with custom message when dividing by zero.
                 *
                 * CAUTION: This function is deprecated because it requires allocating memory for the error
                 * message unnecessarily. For custom revert reasons use {tryMod}.
                 *
                 * Counterpart to Solidity's `%` operator. This function uses a `revert`
                 * opcode (which leaves remaining gas untouched) while Solidity uses an
                 * invalid opcode to revert (consuming all remaining gas).
                 *
                 * Requirements:
                 *
                 * - The divisor cannot be zero.
                 */
                function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                    require(b > 0, errorMessage);
                    return a % b;
                }
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            import "../interface/RocketStorageInterface.sol";
            import "@openzeppelin/contracts/math/SafeMath.sol";
            /// @title The primary persistent storage for Rocket Pool
            /// @author David Rugendyke
            contract RocketStorage is RocketStorageInterface {
                // Events
                event NodeWithdrawalAddressSet(address indexed node, address indexed withdrawalAddress, uint256 time);
                event GuardianChanged(address oldGuardian, address newGuardian);
                // Libraries
                using SafeMath for uint256;
                // Storage maps
                mapping(bytes32 => string)     private stringStorage;
                mapping(bytes32 => bytes)      private bytesStorage;
                mapping(bytes32 => uint256)    private uintStorage;
                mapping(bytes32 => int256)     private intStorage;
                mapping(bytes32 => address)    private addressStorage;
                mapping(bytes32 => bool)       private booleanStorage;
                mapping(bytes32 => bytes32)    private bytes32Storage;
                // Protected storage (not accessible by network contracts)
                mapping(address => address)    private withdrawalAddresses;
                mapping(address => address)    private pendingWithdrawalAddresses;
                // Guardian address
                address guardian;
                address newGuardian;
                // Flag storage has been initialised
                bool storageInit = false;
                /// @dev Only allow access from the latest version of a contract in the Rocket Pool network after deployment
                modifier onlyLatestRocketNetworkContract() {
                    if (storageInit == true) {
                        // Make sure the access is permitted to only contracts in our Dapp
                        require(booleanStorage[keccak256(abi.encodePacked("contract.exists", msg.sender))], "Invalid or outdated network contract");
                    } else {
                        // Only Dapp and the guardian account are allowed access during initialisation.
                        // tx.origin is only safe to use in this case for deployment since no external contracts are interacted with
                        require((
                            booleanStorage[keccak256(abi.encodePacked("contract.exists", msg.sender))] || tx.origin == guardian
                        ), "Invalid or outdated network contract attempting access during deployment");
                    }
                    _;
                }
                /// @dev Construct RocketStorage
                constructor() {
                    // Set the guardian upon deployment
                    guardian = msg.sender;
                }
                // Get guardian address
                function getGuardian() external override view returns (address) {
                    return guardian;
                }
                // Transfers guardianship to a new address
                function setGuardian(address _newAddress) external override {
                    // Check tx comes from current guardian
                    require(msg.sender == guardian, "Is not guardian account");
                    // Store new address awaiting confirmation
                    newGuardian = _newAddress;
                }
                // Confirms change of guardian
                function confirmGuardian() external override {
                    // Check tx came from new guardian address
                    require(msg.sender == newGuardian, "Confirmation must come from new guardian address");
                    // Store old guardian for event
                    address oldGuardian = guardian;
                    // Update guardian and clear storage
                    guardian = newGuardian;
                    delete newGuardian;
                    // Emit event
                    emit GuardianChanged(oldGuardian, guardian);
                }
                // Set this as being deployed now
                function getDeployedStatus() external override view returns (bool) {
                    return storageInit;
                }
                // Set this as being deployed now
                function setDeployedStatus() external {
                    // Only guardian can lock this down
                    require(msg.sender == guardian, "Is not guardian account");
                    // Set it now
                    storageInit = true;
                }
                // Protected storage
                // Get a node's withdrawal address
                function getNodeWithdrawalAddress(address _nodeAddress) public override view returns (address) {
                    // If no withdrawal address has been set, return the nodes address
                    address withdrawalAddress = withdrawalAddresses[_nodeAddress];
                    if (withdrawalAddress == address(0)) {
                        return _nodeAddress;
                    }
                    return withdrawalAddress;
                }
                // Get a node's pending withdrawal address
                function getNodePendingWithdrawalAddress(address _nodeAddress) external override view returns (address) {
                    return pendingWithdrawalAddresses[_nodeAddress];
                }
                // Set a node's withdrawal address
                function setWithdrawalAddress(address _nodeAddress, address _newWithdrawalAddress, bool _confirm) external override {
                    // Check new withdrawal address
                    require(_newWithdrawalAddress != address(0x0), "Invalid withdrawal address");
                    // Confirm the transaction is from the node's current withdrawal address
                    address withdrawalAddress = getNodeWithdrawalAddress(_nodeAddress);
                    require(withdrawalAddress == msg.sender, "Only a tx from a node's withdrawal address can update it");
                    // Update immediately if confirmed
                    if (_confirm) {
                        updateWithdrawalAddress(_nodeAddress, _newWithdrawalAddress);
                    }
                    // Set pending withdrawal address if not confirmed
                    else {
                        pendingWithdrawalAddresses[_nodeAddress] = _newWithdrawalAddress;
                    }
                }
                // Confirm a node's new withdrawal address
                function confirmWithdrawalAddress(address _nodeAddress) external override {
                    // Get node by pending withdrawal address
                    require(pendingWithdrawalAddresses[_nodeAddress] == msg.sender, "Confirmation must come from the pending withdrawal address");
                    delete pendingWithdrawalAddresses[_nodeAddress];
                    // Update withdrawal address
                    updateWithdrawalAddress(_nodeAddress, msg.sender);
                }
                // Update a node's withdrawal address
                function updateWithdrawalAddress(address _nodeAddress, address _newWithdrawalAddress) private {
                    // Set new withdrawal address
                    withdrawalAddresses[_nodeAddress] = _newWithdrawalAddress;
                    // Emit withdrawal address set event
                    emit NodeWithdrawalAddressSet(_nodeAddress, _newWithdrawalAddress, block.timestamp);
                }
                /// @param _key The key for the record
                function getAddress(bytes32 _key) override external view returns (address r) {
                    return addressStorage[_key];
                }
                /// @param _key The key for the record
                function getUint(bytes32 _key) override external view returns (uint256 r) {
                    return uintStorage[_key];
                }
                /// @param _key The key for the record
                function getString(bytes32 _key) override external view returns (string memory) {
                    return stringStorage[_key];
                }
                /// @param _key The key for the record
                function getBytes(bytes32 _key) override external view returns (bytes memory) {
                    return bytesStorage[_key];
                }
                /// @param _key The key for the record
                function getBool(bytes32 _key) override external view returns (bool r) {
                    return booleanStorage[_key];
                }
                /// @param _key The key for the record
                function getInt(bytes32 _key) override external view returns (int r) {
                    return intStorage[_key];
                }
                /// @param _key The key for the record
                function getBytes32(bytes32 _key) override external view returns (bytes32 r) {
                    return bytes32Storage[_key];
                }
                /// @param _key The key for the record
                function setAddress(bytes32 _key, address _value) onlyLatestRocketNetworkContract override external {
                    addressStorage[_key] = _value;
                }
                /// @param _key The key for the record
                function setUint(bytes32 _key, uint _value) onlyLatestRocketNetworkContract override external {
                    uintStorage[_key] = _value;
                }
                /// @param _key The key for the record
                function setString(bytes32 _key, string calldata _value) onlyLatestRocketNetworkContract override external {
                    stringStorage[_key] = _value;
                }
                /// @param _key The key for the record
                function setBytes(bytes32 _key, bytes calldata _value) onlyLatestRocketNetworkContract override external {
                    bytesStorage[_key] = _value;
                }
                /// @param _key The key for the record
                function setBool(bytes32 _key, bool _value) onlyLatestRocketNetworkContract override external {
                    booleanStorage[_key] = _value;
                }
                /// @param _key The key for the record
                function setInt(bytes32 _key, int _value) onlyLatestRocketNetworkContract override external {
                    intStorage[_key] = _value;
                }
                /// @param _key The key for the record
                function setBytes32(bytes32 _key, bytes32 _value) onlyLatestRocketNetworkContract override external {
                    bytes32Storage[_key] = _value;
                }
                /// @param _key The key for the record
                function deleteAddress(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete addressStorage[_key];
                }
                /// @param _key The key for the record
                function deleteUint(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete uintStorage[_key];
                }
                /// @param _key The key for the record
                function deleteString(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete stringStorage[_key];
                }
                /// @param _key The key for the record
                function deleteBytes(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete bytesStorage[_key];
                }
                /// @param _key The key for the record
                function deleteBool(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete booleanStorage[_key];
                }
                /// @param _key The key for the record
                function deleteInt(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete intStorage[_key];
                }
                /// @param _key The key for the record
                function deleteBytes32(bytes32 _key) onlyLatestRocketNetworkContract override external {
                    delete bytes32Storage[_key];
                }
                /// @param _key The key for the record
                /// @param _amount An amount to add to the record's value
                function addUint(bytes32 _key, uint256 _amount) onlyLatestRocketNetworkContract override external {
                    uintStorage[_key] = uintStorage[_key].add(_amount);
                }
                /// @param _key The key for the record
                /// @param _amount An amount to subtract from the record's value
                function subUint(bytes32 _key, uint256 _amount) onlyLatestRocketNetworkContract override external {
                    uintStorage[_key] = uintStorage[_key].sub(_amount);
                }
            }
            /**
              *       .
              *      / \\
              *     |.'.|
              *     |'.'|
              *   ,'|   |`.
              *  |,-'-|-'-.|
              *   __|_| |         _        _      _____           _
              *  | ___ \\|        | |      | |    | ___ \\         | |
              *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
              *  |    // _ \\ / __| |/ / _ \\ __|  |  __/ _ \\ / _ \\| |
              *  | |\\ \\ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
              *  \\_| \\_\\___/ \\___|_|\\_\\___|\\__|  \\_|  \\___/ \\___/|_|
              * +---------------------------------------------------+
              * |    DECENTRALISED STAKING PROTOCOL FOR ETHEREUM    |
              * +---------------------------------------------------+
              *
              *  Rocket Pool is a first-of-its-kind Ethereum staking pool protocol, designed to
              *  be community-owned, decentralised, and trustless.
              *
              *  For more information about Rocket Pool, visit https://rocketpool.net
              *
              *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
              *
              */
            pragma solidity 0.7.6;
            // SPDX-License-Identifier: GPL-3.0-only
            interface RocketStorageInterface {
                // Deploy status
                function getDeployedStatus() external view returns (bool);
                // Guardian
                function getGuardian() external view returns(address);
                function setGuardian(address _newAddress) external;
                function confirmGuardian() external;
                // Getters
                function getAddress(bytes32 _key) external view returns (address);
                function getUint(bytes32 _key) external view returns (uint);
                function getString(bytes32 _key) external view returns (string memory);
                function getBytes(bytes32 _key) external view returns (bytes memory);
                function getBool(bytes32 _key) external view returns (bool);
                function getInt(bytes32 _key) external view returns (int);
                function getBytes32(bytes32 _key) external view returns (bytes32);
                // Setters
                function setAddress(bytes32 _key, address _value) external;
                function setUint(bytes32 _key, uint _value) external;
                function setString(bytes32 _key, string calldata _value) external;
                function setBytes(bytes32 _key, bytes calldata _value) external;
                function setBool(bytes32 _key, bool _value) external;
                function setInt(bytes32 _key, int _value) external;
                function setBytes32(bytes32 _key, bytes32 _value) external;
                // Deleters
                function deleteAddress(bytes32 _key) external;
                function deleteUint(bytes32 _key) external;
                function deleteString(bytes32 _key) external;
                function deleteBytes(bytes32 _key) external;
                function deleteBool(bytes32 _key) external;
                function deleteInt(bytes32 _key) external;
                function deleteBytes32(bytes32 _key) external;
                // Arithmetic
                function addUint(bytes32 _key, uint256 _amount) external;
                function subUint(bytes32 _key, uint256 _amount) external;
                // Protected storage
                function getNodeWithdrawalAddress(address _nodeAddress) external view returns (address);
                function getNodePendingWithdrawalAddress(address _nodeAddress) external view returns (address);
                function setWithdrawalAddress(address _nodeAddress, address _newWithdrawalAddress, bool _confirm) external;
                function confirmWithdrawalAddress(address _nodeAddress) external;
            }