ETH Price: $3,773.93 (+1.06%)
Gas: 4 Gwei

Transaction Decoder

Block:
19671429 at Apr-16-2024 11:51:47 PM +UTC
Transaction Fee:
0.000454958 ETH $1.72
Gas Used:
64,994 Gas / 7 Gwei

Emitted Events:

165 GnosisSafeProxy.0x3d0ce9bfc3ed7d6862dbb28b2dea94561fe714a1b4d019aa8af39730d1ad7c3d( 0x3d0ce9bfc3ed7d6862dbb28b2dea94561fe714a1b4d019aa8af39730d1ad7c3d, 0x0000000000000000000000001f75881dc0707b5236f739b5b64a87c211294abb, 0000000000000000000000000000000000000000000000000078cad1e25d0004 )
166 ElixirDeposit.Deposit( caller=[Sender] 0xc1849d147dc883e5b5d4923ae49234a4fe8ea1ef, amount=34000000000000004 )

Account State Difference:

  Address   Before After State Difference Code
0x1F75881D...211294Abb
0x4B4EEC1D...993f9e586 1,488.413267463852251928 Eth1,488.447267463852251932 Eth0.034000000000000004
(beaverbuild)
18.589623533363441295 Eth18.589650844537547107 Eth0.000027311174105812
0xc1849D14...4FE8ea1ef
0.544321434661219546 Eth
Nonce: 179
0.509866476661219542 Eth
Nonce: 180
0.034454958000000004

Execution Trace

ETH 0.034000000000000004 ElixirDeposit.CALL( )
  • ETH 0.034000000000000004 GnosisSafeProxy.CALL( )
    • ETH 0.034000000000000004 GnosisSafe.DELEGATECALL( )
      File 1 of 3: ElixirDeposit
      // SPDX-License-Identifier: BUSL-1.1
      pragma solidity 0.8.20;
      import {Ownable} from "openzeppelin/access/Ownable.sol";
      /// @title Elixir deposit contract
      /// @author The Elixir Team
      /// @notice This contract is used to deposit funds
      contract ElixirDeposit is Ownable {
          /*//////////////////////////////////////////////////////////////
                                      VARIABLES
          //////////////////////////////////////////////////////////////*/
          /// @notice The address of the Elixir multisig wallet with control of funds
          address public controller;
          /// @notice Mapping of address to deposited amount
          mapping(address user => uint256 amount) public deposits;
          /// @notice The pause status of deposits. True if deposits are paused.
          bool public depositsPaused;
          /*//////////////////////////////////////////////////////////////
                                       EVENTS
          //////////////////////////////////////////////////////////////*/
          /// @notice Emitted when a deposit is made.
          /// @param caller The caller of the deposit function, for which tokens are taken from.
          /// @param amount The token amount deposited.
          event Deposit(address indexed caller, uint256 indexed amount);
          /*//////////////////////////////////////////////////////////////
                                       ERRORS
          //////////////////////////////////////////////////////////////*/
          /// @notice Emitted when deposits are paused.
          error DepositsPaused();
          /// @notice Emitted when deposit fails.
          error DepositFailed();
          /*//////////////////////////////////////////////////////////////
                                      MODIFIERS
          //////////////////////////////////////////////////////////////*/
          /// @notice Reverts when deposits are paused.
          modifier whenDepositNotPaused() {
              if (depositsPaused) revert DepositsPaused();
              _;
          }
          /*//////////////////////////////////////////////////////////////
                                     CONSTRUCTOR
          //////////////////////////////////////////////////////////////*/
          /// @notice Constructor for the ElixirDeposit contract
          /// @param _owner The address of the owner of the contract
          constructor(address _owner) Ownable(_owner) {}
          /*//////////////////////////////////////////////////////////////
                                   EXTERNAL FUNCTIONS
          //////////////////////////////////////////////////////////////*/
          /// @notice Deposit funds into the contract
          function deposit() external payable whenDepositNotPaused {
              deposits[msg.sender] += msg.value;
              (bool sent,) = controller.call{value: msg.value}("");
              if (!sent) revert DepositFailed();
              emit Deposit(msg.sender, msg.value);
          }
          /// @notice Pause deposits, callable by the owner
          /// @param pauseDeposits True if deposits are to be paused, false if they are to be unpaused
          function pause(bool pauseDeposits) external onlyOwner {
              depositsPaused = pauseDeposits;
          }
          /// @notice Set controller address, callable by the owner
          /// @param _controller controller address to be set
          function setController(address _controller) external onlyOwner {
              controller = _controller;
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)
      pragma solidity ^0.8.20;
      import {Context} from "../utils/Context.sol";
      /**
       * @dev Contract module which provides a basic access control mechanism, where
       * there is an account (an owner) that can be granted exclusive access to
       * specific functions.
       *
       * The initial owner is set to the address provided by the deployer. This can
       * later be changed with {transferOwnership}.
       *
       * This module is used through inheritance. It will make available the modifier
       * `onlyOwner`, which can be applied to your functions to restrict their use to
       * the owner.
       */
      abstract contract Ownable is Context {
          address private _owner;
          /**
           * @dev The caller account is not authorized to perform an operation.
           */
          error OwnableUnauthorizedAccount(address account);
          /**
           * @dev The owner is not a valid owner account. (eg. `address(0)`)
           */
          error OwnableInvalidOwner(address owner);
          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
          /**
           * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
           */
          constructor(address initialOwner) {
              if (initialOwner == address(0)) {
                  revert OwnableInvalidOwner(address(0));
              }
              _transferOwnership(initialOwner);
          }
          /**
           * @dev Throws if called by any account other than the owner.
           */
          modifier onlyOwner() {
              _checkOwner();
              _;
          }
          /**
           * @dev Returns the address of the current owner.
           */
          function owner() public view virtual returns (address) {
              return _owner;
          }
          /**
           * @dev Throws if the sender is not the owner.
           */
          function _checkOwner() internal view virtual {
              if (owner() != _msgSender()) {
                  revert OwnableUnauthorizedAccount(_msgSender());
              }
          }
          /**
           * @dev Leaves the contract without owner. It will not be possible to call
           * `onlyOwner` functions. Can only be called by the current owner.
           *
           * NOTE: Renouncing ownership will leave the contract without an owner,
           * thereby disabling any functionality that is only available to the owner.
           */
          function renounceOwnership() public virtual onlyOwner {
              _transferOwnership(address(0));
          }
          /**
           * @dev Transfers ownership of the contract to a new account (`newOwner`).
           * Can only be called by the current owner.
           */
          function transferOwnership(address newOwner) public virtual onlyOwner {
              if (newOwner == address(0)) {
                  revert OwnableInvalidOwner(address(0));
              }
              _transferOwnership(newOwner);
          }
          /**
           * @dev Transfers ownership of the contract to a new account (`newOwner`).
           * Internal function without access restriction.
           */
          function _transferOwnership(address newOwner) internal virtual {
              address oldOwner = _owner;
              _owner = newOwner;
              emit OwnershipTransferred(oldOwner, newOwner);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)
      pragma solidity ^0.8.20;
      /**
       * @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 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) {
              return msg.sender;
          }
          function _msgData() internal view virtual returns (bytes calldata) {
              return msg.data;
          }
          function _contextSuffixLength() internal view virtual returns (uint256) {
              return 0;
          }
      }
      

      File 2 of 3: GnosisSafeProxy
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      
      /// @title IProxy - Helper interface to access masterCopy of the Proxy on-chain
      /// @author Richard Meissner - <[email protected]>
      interface IProxy {
          function masterCopy() external view returns (address);
      }
      
      /// @title GnosisSafeProxy - Generic proxy contract allows to execute all transactions applying the code of a master contract.
      /// @author Stefan George - <[email protected]>
      /// @author Richard Meissner - <[email protected]>
      contract GnosisSafeProxy {
          // singleton always needs to be first declared variable, to ensure that it is at the same location in the contracts to which calls are delegated.
          // To reduce deployment costs this variable is internal and needs to be retrieved via `getStorageAt`
          address internal singleton;
      
          /// @dev Constructor function sets address of singleton contract.
          /// @param _singleton Singleton address.
          constructor(address _singleton) {
              require(_singleton != address(0), "Invalid singleton address provided");
              singleton = _singleton;
          }
      
          /// @dev Fallback function forwards all transactions and returns all received return data.
          fallback() external payable {
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  let _singleton := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
                  // 0xa619486e == keccak("masterCopy()"). The value is right padded to 32-bytes with 0s
                  if eq(calldataload(0), 0xa619486e00000000000000000000000000000000000000000000000000000000) {
                      mstore(0, _singleton)
                      return(0, 0x20)
                  }
                  calldatacopy(0, 0, calldatasize())
                  let success := delegatecall(gas(), _singleton, 0, calldatasize(), 0, 0)
                  returndatacopy(0, 0, returndatasize())
                  if eq(success, 0) {
                      revert(0, returndatasize())
                  }
                  return(0, returndatasize())
              }
          }
      }
      
      /// @title Proxy Factory - Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
      /// @author Stefan George - <[email protected]>
      contract GnosisSafeProxyFactory {
          event ProxyCreation(GnosisSafeProxy proxy, address singleton);
      
          /// @dev Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
          /// @param singleton Address of singleton contract.
          /// @param data Payload for message call sent to new proxy contract.
          function createProxy(address singleton, bytes memory data) public returns (GnosisSafeProxy proxy) {
              proxy = new GnosisSafeProxy(singleton);
              if (data.length > 0)
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      if eq(call(gas(), proxy, 0, add(data, 0x20), mload(data), 0, 0), 0) {
                          revert(0, 0)
                      }
                  }
              emit ProxyCreation(proxy, singleton);
          }
      
          /// @dev Allows to retrieve the runtime code of a deployed Proxy. This can be used to check that the expected Proxy was deployed.
          function proxyRuntimeCode() public pure returns (bytes memory) {
              return type(GnosisSafeProxy).runtimeCode;
          }
      
          /// @dev Allows to retrieve the creation code used for the Proxy deployment. With this it is easily possible to calculate predicted address.
          function proxyCreationCode() public pure returns (bytes memory) {
              return type(GnosisSafeProxy).creationCode;
          }
      
          /// @dev Allows to create new proxy contact using CREATE2 but it doesn't run the initializer.
          ///      This method is only meant as an utility to be called from other methods
          /// @param _singleton Address of singleton contract.
          /// @param initializer Payload for message call sent to new proxy contract.
          /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
          function deployProxyWithNonce(
              address _singleton,
              bytes memory initializer,
              uint256 saltNonce
          ) internal returns (GnosisSafeProxy proxy) {
              // If the initializer changes the proxy address should change too. Hashing the initializer data is cheaper than just concatinating it
              bytes32 salt = keccak256(abi.encodePacked(keccak256(initializer), saltNonce));
              bytes memory deploymentData = abi.encodePacked(type(GnosisSafeProxy).creationCode, uint256(uint160(_singleton)));
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  proxy := create2(0x0, add(0x20, deploymentData), mload(deploymentData), salt)
              }
              require(address(proxy) != address(0), "Create2 call failed");
          }
      
          /// @dev Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
          /// @param _singleton Address of singleton contract.
          /// @param initializer Payload for message call sent to new proxy contract.
          /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
          function createProxyWithNonce(
              address _singleton,
              bytes memory initializer,
              uint256 saltNonce
          ) public returns (GnosisSafeProxy proxy) {
              proxy = deployProxyWithNonce(_singleton, initializer, saltNonce);
              if (initializer.length > 0)
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      if eq(call(gas(), proxy, 0, add(initializer, 0x20), mload(initializer), 0, 0), 0) {
                          revert(0, 0)
                      }
                  }
              emit ProxyCreation(proxy, _singleton);
          }
      
          /// @dev Allows to create new proxy contact, execute a message call to the new proxy and call a specified callback within one transaction
          /// @param _singleton Address of singleton contract.
          /// @param initializer Payload for message call sent to new proxy contract.
          /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
          /// @param callback Callback that will be invoced after the new proxy contract has been successfully deployed and initialized.
          function createProxyWithCallback(
              address _singleton,
              bytes memory initializer,
              uint256 saltNonce,
              IProxyCreationCallback callback
          ) public returns (GnosisSafeProxy proxy) {
              uint256 saltNonceWithCallback = uint256(keccak256(abi.encodePacked(saltNonce, callback)));
              proxy = createProxyWithNonce(_singleton, initializer, saltNonceWithCallback);
              if (address(callback) != address(0)) callback.proxyCreated(proxy, _singleton, initializer, saltNonce);
          }
      
          /// @dev Allows to get the address for a new proxy contact created via `createProxyWithNonce`
          ///      This method is only meant for address calculation purpose when you use an initializer that would revert,
          ///      therefore the response is returned with a revert. When calling this method set `from` to the address of the proxy factory.
          /// @param _singleton Address of singleton contract.
          /// @param initializer Payload for message call sent to new proxy contract.
          /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
          function calculateCreateProxyWithNonceAddress(
              address _singleton,
              bytes calldata initializer,
              uint256 saltNonce
          ) external returns (GnosisSafeProxy proxy) {
              proxy = deployProxyWithNonce(_singleton, initializer, saltNonce);
              revert(string(abi.encodePacked(proxy)));
          }
      }
      
      interface IProxyCreationCallback {
          function proxyCreated(
              GnosisSafeProxy proxy,
              address _singleton,
              bytes calldata initializer,
              uint256 saltNonce
          ) external;
      }

      File 3 of 3: GnosisSafe
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      import "./base/ModuleManager.sol";
      import "./base/OwnerManager.sol";
      import "./base/FallbackManager.sol";
      import "./base/GuardManager.sol";
      import "./common/EtherPaymentFallback.sol";
      import "./common/Singleton.sol";
      import "./common/SignatureDecoder.sol";
      import "./common/SecuredTokenTransfer.sol";
      import "./common/StorageAccessible.sol";
      import "./interfaces/ISignatureValidator.sol";
      import "./external/GnosisSafeMath.sol";
      /// @title Gnosis Safe - A multisignature wallet with support for confirmations using signed messages based on ERC191.
      /// @author Stefan George - <[email protected]>
      /// @author Richard Meissner - <[email protected]>
      contract GnosisSafe is
          EtherPaymentFallback,
          Singleton,
          ModuleManager,
          OwnerManager,
          SignatureDecoder,
          SecuredTokenTransfer,
          ISignatureValidatorConstants,
          FallbackManager,
          StorageAccessible,
          GuardManager
      {
          using GnosisSafeMath for uint256;
          string public constant VERSION = "1.3.0";
          // keccak256(
          //     "EIP712Domain(uint256 chainId,address verifyingContract)"
          // );
          bytes32 private constant DOMAIN_SEPARATOR_TYPEHASH = 0x47e79534a245952e8b16893a336b85a3d9ea9fa8c573f3d803afb92a79469218;
          // keccak256(
          //     "SafeTx(address to,uint256 value,bytes data,uint8 operation,uint256 safeTxGas,uint256 baseGas,uint256 gasPrice,address gasToken,address refundReceiver,uint256 nonce)"
          // );
          bytes32 private constant SAFE_TX_TYPEHASH = 0xbb8310d486368db6bd6f849402fdd73ad53d316b5a4b2644ad6efe0f941286d8;
          event SafeSetup(address indexed initiator, address[] owners, uint256 threshold, address initializer, address fallbackHandler);
          event ApproveHash(bytes32 indexed approvedHash, address indexed owner);
          event SignMsg(bytes32 indexed msgHash);
          event ExecutionFailure(bytes32 txHash, uint256 payment);
          event ExecutionSuccess(bytes32 txHash, uint256 payment);
          uint256 public nonce;
          bytes32 private _deprecatedDomainSeparator;
          // Mapping to keep track of all message hashes that have been approve by ALL REQUIRED owners
          mapping(bytes32 => uint256) public signedMessages;
          // Mapping to keep track of all hashes (message or transaction) that have been approve by ANY owners
          mapping(address => mapping(bytes32 => uint256)) public approvedHashes;
          // This constructor ensures that this contract can only be used as a master copy for Proxy contracts
          constructor() {
              // By setting the threshold it is not possible to call setup anymore,
              // so we create a Safe with 0 owners and threshold 1.
              // This is an unusable Safe, perfect for the singleton
              threshold = 1;
          }
          /// @dev Setup function sets initial storage of contract.
          /// @param _owners List of Safe owners.
          /// @param _threshold Number of required confirmations for a Safe transaction.
          /// @param to Contract address for optional delegate call.
          /// @param data Data payload for optional delegate call.
          /// @param fallbackHandler Handler for fallback calls to this contract
          /// @param paymentToken Token that should be used for the payment (0 is ETH)
          /// @param payment Value that should be paid
          /// @param paymentReceiver Adddress that should receive the payment (or 0 if tx.origin)
          function setup(
              address[] calldata _owners,
              uint256 _threshold,
              address to,
              bytes calldata data,
              address fallbackHandler,
              address paymentToken,
              uint256 payment,
              address payable paymentReceiver
          ) external {
              // setupOwners checks if the Threshold is already set, therefore preventing that this method is called twice
              setupOwners(_owners, _threshold);
              if (fallbackHandler != address(0)) internalSetFallbackHandler(fallbackHandler);
              // As setupOwners can only be called if the contract has not been initialized we don't need a check for setupModules
              setupModules(to, data);
              if (payment > 0) {
                  // To avoid running into issues with EIP-170 we reuse the handlePayment function (to avoid adjusting code of that has been verified we do not adjust the method itself)
                  // baseGas = 0, gasPrice = 1 and gas = payment => amount = (payment + 0) * 1 = payment
                  handlePayment(payment, 0, 1, paymentToken, paymentReceiver);
              }
              emit SafeSetup(msg.sender, _owners, _threshold, to, fallbackHandler);
          }
          /// @dev Allows to execute a Safe transaction confirmed by required number of owners and then pays the account that submitted the transaction.
          ///      Note: The fees are always transferred, even if the user transaction fails.
          /// @param to Destination address of Safe transaction.
          /// @param value Ether value of Safe transaction.
          /// @param data Data payload of Safe transaction.
          /// @param operation Operation type of Safe transaction.
          /// @param safeTxGas Gas that should be used for the Safe transaction.
          /// @param baseGas Gas costs that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
          /// @param gasPrice Gas price that should be used for the payment calculation.
          /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
          /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
          /// @param signatures Packed signature data ({bytes32 r}{bytes32 s}{uint8 v})
          function execTransaction(
              address to,
              uint256 value,
              bytes calldata data,
              Enum.Operation operation,
              uint256 safeTxGas,
              uint256 baseGas,
              uint256 gasPrice,
              address gasToken,
              address payable refundReceiver,
              bytes memory signatures
          ) public payable virtual returns (bool success) {
              bytes32 txHash;
              // Use scope here to limit variable lifetime and prevent `stack too deep` errors
              {
                  bytes memory txHashData =
                      encodeTransactionData(
                          // Transaction info
                          to,
                          value,
                          data,
                          operation,
                          safeTxGas,
                          // Payment info
                          baseGas,
                          gasPrice,
                          gasToken,
                          refundReceiver,
                          // Signature info
                          nonce
                      );
                  // Increase nonce and execute transaction.
                  nonce++;
                  txHash = keccak256(txHashData);
                  checkSignatures(txHash, txHashData, signatures);
              }
              address guard = getGuard();
              {
                  if (guard != address(0)) {
                      Guard(guard).checkTransaction(
                          // Transaction info
                          to,
                          value,
                          data,
                          operation,
                          safeTxGas,
                          // Payment info
                          baseGas,
                          gasPrice,
                          gasToken,
                          refundReceiver,
                          // Signature info
                          signatures,
                          msg.sender
                      );
                  }
              }
              // We require some gas to emit the events (at least 2500) after the execution and some to perform code until the execution (500)
              // We also include the 1/64 in the check that is not send along with a call to counteract potential shortings because of EIP-150
              require(gasleft() >= ((safeTxGas * 64) / 63).max(safeTxGas + 2500) + 500, "GS010");
              // Use scope here to limit variable lifetime and prevent `stack too deep` errors
              {
                  uint256 gasUsed = gasleft();
                  // If the gasPrice is 0 we assume that nearly all available gas can be used (it is always more than safeTxGas)
                  // We only substract 2500 (compared to the 3000 before) to ensure that the amount passed is still higher than safeTxGas
                  success = execute(to, value, data, operation, gasPrice == 0 ? (gasleft() - 2500) : safeTxGas);
                  gasUsed = gasUsed.sub(gasleft());
                  // If no safeTxGas and no gasPrice was set (e.g. both are 0), then the internal tx is required to be successful
                  // This makes it possible to use `estimateGas` without issues, as it searches for the minimum gas where the tx doesn't revert
                  require(success || safeTxGas != 0 || gasPrice != 0, "GS013");
                  // We transfer the calculated tx costs to the tx.origin to avoid sending it to intermediate contracts that have made calls
                  uint256 payment = 0;
                  if (gasPrice > 0) {
                      payment = handlePayment(gasUsed, baseGas, gasPrice, gasToken, refundReceiver);
                  }
                  if (success) emit ExecutionSuccess(txHash, payment);
                  else emit ExecutionFailure(txHash, payment);
              }
              {
                  if (guard != address(0)) {
                      Guard(guard).checkAfterExecution(txHash, success);
                  }
              }
          }
          function handlePayment(
              uint256 gasUsed,
              uint256 baseGas,
              uint256 gasPrice,
              address gasToken,
              address payable refundReceiver
          ) private returns (uint256 payment) {
              // solhint-disable-next-line avoid-tx-origin
              address payable receiver = refundReceiver == address(0) ? payable(tx.origin) : refundReceiver;
              if (gasToken == address(0)) {
                  // For ETH we will only adjust the gas price to not be higher than the actual used gas price
                  payment = gasUsed.add(baseGas).mul(gasPrice < tx.gasprice ? gasPrice : tx.gasprice);
                  require(receiver.send(payment), "GS011");
              } else {
                  payment = gasUsed.add(baseGas).mul(gasPrice);
                  require(transferToken(gasToken, receiver, payment), "GS012");
              }
          }
          /**
           * @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
           * @param dataHash Hash of the data (could be either a message hash or transaction hash)
           * @param data That should be signed (this is passed to an external validator contract)
           * @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
           */
          function checkSignatures(
              bytes32 dataHash,
              bytes memory data,
              bytes memory signatures
          ) public view {
              // Load threshold to avoid multiple storage loads
              uint256 _threshold = threshold;
              // Check that a threshold is set
              require(_threshold > 0, "GS001");
              checkNSignatures(dataHash, data, signatures, _threshold);
          }
          /**
           * @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
           * @param dataHash Hash of the data (could be either a message hash or transaction hash)
           * @param data That should be signed (this is passed to an external validator contract)
           * @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
           * @param requiredSignatures Amount of required valid signatures.
           */
          function checkNSignatures(
              bytes32 dataHash,
              bytes memory data,
              bytes memory signatures,
              uint256 requiredSignatures
          ) public view {
              // Check that the provided signature data is not too short
              require(signatures.length >= requiredSignatures.mul(65), "GS020");
              // There cannot be an owner with address 0.
              address lastOwner = address(0);
              address currentOwner;
              uint8 v;
              bytes32 r;
              bytes32 s;
              uint256 i;
              for (i = 0; i < requiredSignatures; i++) {
                  (v, r, s) = signatureSplit(signatures, i);
                  if (v == 0) {
                      // If v is 0 then it is a contract signature
                      // When handling contract signatures the address of the contract is encoded into r
                      currentOwner = address(uint160(uint256(r)));
                      // Check that signature data pointer (s) is not pointing inside the static part of the signatures bytes
                      // This check is not completely accurate, since it is possible that more signatures than the threshold are send.
                      // Here we only check that the pointer is not pointing inside the part that is being processed
                      require(uint256(s) >= requiredSignatures.mul(65), "GS021");
                      // Check that signature data pointer (s) is in bounds (points to the length of data -> 32 bytes)
                      require(uint256(s).add(32) <= signatures.length, "GS022");
                      // Check if the contract signature is in bounds: start of data is s + 32 and end is start + signature length
                      uint256 contractSignatureLen;
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          contractSignatureLen := mload(add(add(signatures, s), 0x20))
                      }
                      require(uint256(s).add(32).add(contractSignatureLen) <= signatures.length, "GS023");
                      // Check signature
                      bytes memory contractSignature;
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          // The signature data for contract signatures is appended to the concatenated signatures and the offset is stored in s
                          contractSignature := add(add(signatures, s), 0x20)
                      }
                      require(ISignatureValidator(currentOwner).isValidSignature(data, contractSignature) == EIP1271_MAGIC_VALUE, "GS024");
                  } else if (v == 1) {
                      // If v is 1 then it is an approved hash
                      // When handling approved hashes the address of the approver is encoded into r
                      currentOwner = address(uint160(uint256(r)));
                      // Hashes are automatically approved by the sender of the message or when they have been pre-approved via a separate transaction
                      require(msg.sender == currentOwner || approvedHashes[currentOwner][dataHash] != 0, "GS025");
                  } else if (v > 30) {
                      // If v > 30 then default va (27,28) has been adjusted for eth_sign flow
                      // To support eth_sign and similar we adjust v and hash the messageHash with the Ethereum message prefix before applying ecrecover
                      currentOwner = ecrecover(keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      32", dataHash)), v - 4, r, s);
                  } else {
                      // Default is the ecrecover flow with the provided data hash
                      // Use ecrecover with the messageHash for EOA signatures
                      currentOwner = ecrecover(dataHash, v, r, s);
                  }
                  require(currentOwner > lastOwner && owners[currentOwner] != address(0) && currentOwner != SENTINEL_OWNERS, "GS026");
                  lastOwner = currentOwner;
              }
          }
          /// @dev Allows to estimate a Safe transaction.
          ///      This method is only meant for estimation purpose, therefore the call will always revert and encode the result in the revert data.
          ///      Since the `estimateGas` function includes refunds, call this method to get an estimated of the costs that are deducted from the safe with `execTransaction`
          /// @param to Destination address of Safe transaction.
          /// @param value Ether value of Safe transaction.
          /// @param data Data payload of Safe transaction.
          /// @param operation Operation type of Safe transaction.
          /// @return Estimate without refunds and overhead fees (base transaction and payload data gas costs).
          /// @notice Deprecated in favor of common/StorageAccessible.sol and will be removed in next version.
          function requiredTxGas(
              address to,
              uint256 value,
              bytes calldata data,
              Enum.Operation operation
          ) external returns (uint256) {
              uint256 startGas = gasleft();
              // We don't provide an error message here, as we use it to return the estimate
              require(execute(to, value, data, operation, gasleft()));
              uint256 requiredGas = startGas - gasleft();
              // Convert response to string and return via error message
              revert(string(abi.encodePacked(requiredGas)));
          }
          /**
           * @dev Marks a hash as approved. This can be used to validate a hash that is used by a signature.
           * @param hashToApprove The hash that should be marked as approved for signatures that are verified by this contract.
           */
          function approveHash(bytes32 hashToApprove) external {
              require(owners[msg.sender] != address(0), "GS030");
              approvedHashes[msg.sender][hashToApprove] = 1;
              emit ApproveHash(hashToApprove, msg.sender);
          }
          /// @dev Returns the chain id used by this contract.
          function getChainId() public view returns (uint256) {
              uint256 id;
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  id := chainid()
              }
              return id;
          }
          function domainSeparator() public view returns (bytes32) {
              return keccak256(abi.encode(DOMAIN_SEPARATOR_TYPEHASH, getChainId(), this));
          }
          /// @dev Returns the bytes that are hashed to be signed by owners.
          /// @param to Destination address.
          /// @param value Ether value.
          /// @param data Data payload.
          /// @param operation Operation type.
          /// @param safeTxGas Gas that should be used for the safe transaction.
          /// @param baseGas Gas costs for that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
          /// @param gasPrice Maximum gas price that should be used for this transaction.
          /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
          /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
          /// @param _nonce Transaction nonce.
          /// @return Transaction hash bytes.
          function encodeTransactionData(
              address to,
              uint256 value,
              bytes calldata data,
              Enum.Operation operation,
              uint256 safeTxGas,
              uint256 baseGas,
              uint256 gasPrice,
              address gasToken,
              address refundReceiver,
              uint256 _nonce
          ) public view returns (bytes memory) {
              bytes32 safeTxHash =
                  keccak256(
                      abi.encode(
                          SAFE_TX_TYPEHASH,
                          to,
                          value,
                          keccak256(data),
                          operation,
                          safeTxGas,
                          baseGas,
                          gasPrice,
                          gasToken,
                          refundReceiver,
                          _nonce
                      )
                  );
              return abi.encodePacked(bytes1(0x19), bytes1(0x01), domainSeparator(), safeTxHash);
          }
          /// @dev Returns hash to be signed by owners.
          /// @param to Destination address.
          /// @param value Ether value.
          /// @param data Data payload.
          /// @param operation Operation type.
          /// @param safeTxGas Fas that should be used for the safe transaction.
          /// @param baseGas Gas costs for data used to trigger the safe transaction.
          /// @param gasPrice Maximum gas price that should be used for this transaction.
          /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
          /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
          /// @param _nonce Transaction nonce.
          /// @return Transaction hash.
          function getTransactionHash(
              address to,
              uint256 value,
              bytes calldata data,
              Enum.Operation operation,
              uint256 safeTxGas,
              uint256 baseGas,
              uint256 gasPrice,
              address gasToken,
              address refundReceiver,
              uint256 _nonce
          ) public view returns (bytes32) {
              return keccak256(encodeTransactionData(to, value, data, operation, safeTxGas, baseGas, gasPrice, gasToken, refundReceiver, _nonce));
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      import "../common/Enum.sol";
      /// @title Executor - A contract that can execute transactions
      /// @author Richard Meissner - <[email protected]>
      contract Executor {
          function execute(
              address to,
              uint256 value,
              bytes memory data,
              Enum.Operation operation,
              uint256 txGas
          ) internal returns (bool success) {
              if (operation == Enum.Operation.DelegateCall) {
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      success := delegatecall(txGas, to, add(data, 0x20), mload(data), 0, 0)
                  }
              } else {
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      success := call(txGas, to, value, add(data, 0x20), mload(data), 0, 0)
                  }
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      import "../common/SelfAuthorized.sol";
      /// @title Fallback Manager - A contract that manages fallback calls made to this contract
      /// @author Richard Meissner - <[email protected]>
      contract FallbackManager is SelfAuthorized {
          event ChangedFallbackHandler(address handler);
          // keccak256("fallback_manager.handler.address")
          bytes32 internal constant FALLBACK_HANDLER_STORAGE_SLOT = 0x6c9a6c4a39284e37ed1cf53d337577d14212a4870fb976a4366c693b939918d5;
          function internalSetFallbackHandler(address handler) internal {
              bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  sstore(slot, handler)
              }
          }
          /// @dev Allows to add a contract to handle fallback calls.
          ///      Only fallback calls without value and with data will be forwarded.
          ///      This can only be done via a Safe transaction.
          /// @param handler contract to handle fallbacks calls.
          function setFallbackHandler(address handler) public authorized {
              internalSetFallbackHandler(handler);
              emit ChangedFallbackHandler(handler);
          }
          // solhint-disable-next-line payable-fallback,no-complex-fallback
          fallback() external {
              bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  let handler := sload(slot)
                  if iszero(handler) {
                      return(0, 0)
                  }
                  calldatacopy(0, 0, calldatasize())
                  // The msg.sender address is shifted to the left by 12 bytes to remove the padding
                  // Then the address without padding is stored right after the calldata
                  mstore(calldatasize(), shl(96, caller()))
                  // Add 20 bytes for the address appended add the end
                  let success := call(gas(), handler, 0, 0, add(calldatasize(), 20), 0, 0)
                  returndatacopy(0, 0, returndatasize())
                  if iszero(success) {
                      revert(0, returndatasize())
                  }
                  return(0, returndatasize())
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      import "../common/Enum.sol";
      import "../common/SelfAuthorized.sol";
      interface Guard {
          function checkTransaction(
              address to,
              uint256 value,
              bytes memory data,
              Enum.Operation operation,
              uint256 safeTxGas,
              uint256 baseGas,
              uint256 gasPrice,
              address gasToken,
              address payable refundReceiver,
              bytes memory signatures,
              address msgSender
          ) external;
          function checkAfterExecution(bytes32 txHash, bool success) external;
      }
      /// @title Fallback Manager - A contract that manages fallback calls made to this contract
      /// @author Richard Meissner - <[email protected]>
      contract GuardManager is SelfAuthorized {
          event ChangedGuard(address guard);
          // keccak256("guard_manager.guard.address")
          bytes32 internal constant GUARD_STORAGE_SLOT = 0x4a204f620c8c5ccdca3fd54d003badd85ba500436a431f0cbda4f558c93c34c8;
          /// @dev Set a guard that checks transactions before execution
          /// @param guard The address of the guard to be used or the 0 address to disable the guard
          function setGuard(address guard) external authorized {
              bytes32 slot = GUARD_STORAGE_SLOT;
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  sstore(slot, guard)
              }
              emit ChangedGuard(guard);
          }
          function getGuard() internal view returns (address guard) {
              bytes32 slot = GUARD_STORAGE_SLOT;
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  guard := sload(slot)
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      import "../common/Enum.sol";
      import "../common/SelfAuthorized.sol";
      import "./Executor.sol";
      /// @title Module Manager - A contract that manages modules that can execute transactions via this contract
      /// @author Stefan George - <[email protected]>
      /// @author Richard Meissner - <[email protected]>
      contract ModuleManager is SelfAuthorized, Executor {
          event EnabledModule(address module);
          event DisabledModule(address module);
          event ExecutionFromModuleSuccess(address indexed module);
          event ExecutionFromModuleFailure(address indexed module);
          address internal constant SENTINEL_MODULES = address(0x1);
          mapping(address => address) internal modules;
          function setupModules(address to, bytes memory data) internal {
              require(modules[SENTINEL_MODULES] == address(0), "GS100");
              modules[SENTINEL_MODULES] = SENTINEL_MODULES;
              if (to != address(0))
                  // Setup has to complete successfully or transaction fails.
                  require(execute(to, 0, data, Enum.Operation.DelegateCall, gasleft()), "GS000");
          }
          /// @dev Allows to add a module to the whitelist.
          ///      This can only be done via a Safe transaction.
          /// @notice Enables the module `module` for the Safe.
          /// @param module Module to be whitelisted.
          function enableModule(address module) public authorized {
              // Module address cannot be null or sentinel.
              require(module != address(0) && module != SENTINEL_MODULES, "GS101");
              // Module cannot be added twice.
              require(modules[module] == address(0), "GS102");
              modules[module] = modules[SENTINEL_MODULES];
              modules[SENTINEL_MODULES] = module;
              emit EnabledModule(module);
          }
          /// @dev Allows to remove a module from the whitelist.
          ///      This can only be done via a Safe transaction.
          /// @notice Disables the module `module` for the Safe.
          /// @param prevModule Module that pointed to the module to be removed in the linked list
          /// @param module Module to be removed.
          function disableModule(address prevModule, address module) public authorized {
              // Validate module address and check that it corresponds to module index.
              require(module != address(0) && module != SENTINEL_MODULES, "GS101");
              require(modules[prevModule] == module, "GS103");
              modules[prevModule] = modules[module];
              modules[module] = address(0);
              emit DisabledModule(module);
          }
          /// @dev Allows a Module to execute a Safe transaction without any further confirmations.
          /// @param to Destination address of module transaction.
          /// @param value Ether value of module transaction.
          /// @param data Data payload of module transaction.
          /// @param operation Operation type of module transaction.
          function execTransactionFromModule(
              address to,
              uint256 value,
              bytes memory data,
              Enum.Operation operation
          ) public virtual returns (bool success) {
              // Only whitelisted modules are allowed.
              require(msg.sender != SENTINEL_MODULES && modules[msg.sender] != address(0), "GS104");
              // Execute transaction without further confirmations.
              success = execute(to, value, data, operation, gasleft());
              if (success) emit ExecutionFromModuleSuccess(msg.sender);
              else emit ExecutionFromModuleFailure(msg.sender);
          }
          /// @dev Allows a Module to execute a Safe transaction without any further confirmations and return data
          /// @param to Destination address of module transaction.
          /// @param value Ether value of module transaction.
          /// @param data Data payload of module transaction.
          /// @param operation Operation type of module transaction.
          function execTransactionFromModuleReturnData(
              address to,
              uint256 value,
              bytes memory data,
              Enum.Operation operation
          ) public returns (bool success, bytes memory returnData) {
              success = execTransactionFromModule(to, value, data, operation);
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  // Load free memory location
                  let ptr := mload(0x40)
                  // We allocate memory for the return data by setting the free memory location to
                  // current free memory location + data size + 32 bytes for data size value
                  mstore(0x40, add(ptr, add(returndatasize(), 0x20)))
                  // Store the size
                  mstore(ptr, returndatasize())
                  // Store the data
                  returndatacopy(add(ptr, 0x20), 0, returndatasize())
                  // Point the return data to the correct memory location
                  returnData := ptr
              }
          }
          /// @dev Returns if an module is enabled
          /// @return True if the module is enabled
          function isModuleEnabled(address module) public view returns (bool) {
              return SENTINEL_MODULES != module && modules[module] != address(0);
          }
          /// @dev Returns array of modules.
          /// @param start Start of the page.
          /// @param pageSize Maximum number of modules that should be returned.
          /// @return array Array of modules.
          /// @return next Start of the next page.
          function getModulesPaginated(address start, uint256 pageSize) external view returns (address[] memory array, address next) {
              // Init array with max page size
              array = new address[](pageSize);
              // Populate return array
              uint256 moduleCount = 0;
              address currentModule = modules[start];
              while (currentModule != address(0x0) && currentModule != SENTINEL_MODULES && moduleCount < pageSize) {
                  array[moduleCount] = currentModule;
                  currentModule = modules[currentModule];
                  moduleCount++;
              }
              next = currentModule;
              // Set correct size of returned array
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  mstore(array, moduleCount)
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      import "../common/SelfAuthorized.sol";
      /// @title OwnerManager - Manages a set of owners and a threshold to perform actions.
      /// @author Stefan George - <[email protected]>
      /// @author Richard Meissner - <[email protected]>
      contract OwnerManager is SelfAuthorized {
          event AddedOwner(address owner);
          event RemovedOwner(address owner);
          event ChangedThreshold(uint256 threshold);
          address internal constant SENTINEL_OWNERS = address(0x1);
          mapping(address => address) internal owners;
          uint256 internal ownerCount;
          uint256 internal threshold;
          /// @dev Setup function sets initial storage of contract.
          /// @param _owners List of Safe owners.
          /// @param _threshold Number of required confirmations for a Safe transaction.
          function setupOwners(address[] memory _owners, uint256 _threshold) internal {
              // Threshold can only be 0 at initialization.
              // Check ensures that setup function can only be called once.
              require(threshold == 0, "GS200");
              // Validate that threshold is smaller than number of added owners.
              require(_threshold <= _owners.length, "GS201");
              // There has to be at least one Safe owner.
              require(_threshold >= 1, "GS202");
              // Initializing Safe owners.
              address currentOwner = SENTINEL_OWNERS;
              for (uint256 i = 0; i < _owners.length; i++) {
                  // Owner address cannot be null.
                  address owner = _owners[i];
                  require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this) && currentOwner != owner, "GS203");
                  // No duplicate owners allowed.
                  require(owners[owner] == address(0), "GS204");
                  owners[currentOwner] = owner;
                  currentOwner = owner;
              }
              owners[currentOwner] = SENTINEL_OWNERS;
              ownerCount = _owners.length;
              threshold = _threshold;
          }
          /// @dev Allows to add a new owner to the Safe and update the threshold at the same time.
          ///      This can only be done via a Safe transaction.
          /// @notice Adds the owner `owner` to the Safe and updates the threshold to `_threshold`.
          /// @param owner New owner address.
          /// @param _threshold New threshold.
          function addOwnerWithThreshold(address owner, uint256 _threshold) public authorized {
              // Owner address cannot be null, the sentinel or the Safe itself.
              require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this), "GS203");
              // No duplicate owners allowed.
              require(owners[owner] == address(0), "GS204");
              owners[owner] = owners[SENTINEL_OWNERS];
              owners[SENTINEL_OWNERS] = owner;
              ownerCount++;
              emit AddedOwner(owner);
              // Change threshold if threshold was changed.
              if (threshold != _threshold) changeThreshold(_threshold);
          }
          /// @dev Allows to remove an owner from the Safe and update the threshold at the same time.
          ///      This can only be done via a Safe transaction.
          /// @notice Removes the owner `owner` from the Safe and updates the threshold to `_threshold`.
          /// @param prevOwner Owner that pointed to the owner to be removed in the linked list
          /// @param owner Owner address to be removed.
          /// @param _threshold New threshold.
          function removeOwner(
              address prevOwner,
              address owner,
              uint256 _threshold
          ) public authorized {
              // Only allow to remove an owner, if threshold can still be reached.
              require(ownerCount - 1 >= _threshold, "GS201");
              // Validate owner address and check that it corresponds to owner index.
              require(owner != address(0) && owner != SENTINEL_OWNERS, "GS203");
              require(owners[prevOwner] == owner, "GS205");
              owners[prevOwner] = owners[owner];
              owners[owner] = address(0);
              ownerCount--;
              emit RemovedOwner(owner);
              // Change threshold if threshold was changed.
              if (threshold != _threshold) changeThreshold(_threshold);
          }
          /// @dev Allows to swap/replace an owner from the Safe with another address.
          ///      This can only be done via a Safe transaction.
          /// @notice Replaces the owner `oldOwner` in the Safe with `newOwner`.
          /// @param prevOwner Owner that pointed to the owner to be replaced in the linked list
          /// @param oldOwner Owner address to be replaced.
          /// @param newOwner New owner address.
          function swapOwner(
              address prevOwner,
              address oldOwner,
              address newOwner
          ) public authorized {
              // Owner address cannot be null, the sentinel or the Safe itself.
              require(newOwner != address(0) && newOwner != SENTINEL_OWNERS && newOwner != address(this), "GS203");
              // No duplicate owners allowed.
              require(owners[newOwner] == address(0), "GS204");
              // Validate oldOwner address and check that it corresponds to owner index.
              require(oldOwner != address(0) && oldOwner != SENTINEL_OWNERS, "GS203");
              require(owners[prevOwner] == oldOwner, "GS205");
              owners[newOwner] = owners[oldOwner];
              owners[prevOwner] = newOwner;
              owners[oldOwner] = address(0);
              emit RemovedOwner(oldOwner);
              emit AddedOwner(newOwner);
          }
          /// @dev Allows to update the number of required confirmations by Safe owners.
          ///      This can only be done via a Safe transaction.
          /// @notice Changes the threshold of the Safe to `_threshold`.
          /// @param _threshold New threshold.
          function changeThreshold(uint256 _threshold) public authorized {
              // Validate that threshold is smaller than number of owners.
              require(_threshold <= ownerCount, "GS201");
              // There has to be at least one Safe owner.
              require(_threshold >= 1, "GS202");
              threshold = _threshold;
              emit ChangedThreshold(threshold);
          }
          function getThreshold() public view returns (uint256) {
              return threshold;
          }
          function isOwner(address owner) public view returns (bool) {
              return owner != SENTINEL_OWNERS && owners[owner] != address(0);
          }
          /// @dev Returns array of owners.
          /// @return Array of Safe owners.
          function getOwners() public view returns (address[] memory) {
              address[] memory array = new address[](ownerCount);
              // populate return array
              uint256 index = 0;
              address currentOwner = owners[SENTINEL_OWNERS];
              while (currentOwner != SENTINEL_OWNERS) {
                  array[index] = currentOwner;
                  currentOwner = owners[currentOwner];
                  index++;
              }
              return array;
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title Enum - Collection of enums
      /// @author Richard Meissner - <[email protected]>
      contract Enum {
          enum Operation {Call, DelegateCall}
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title EtherPaymentFallback - A contract that has a fallback to accept ether payments
      /// @author Richard Meissner - <[email protected]>
      contract EtherPaymentFallback {
          event SafeReceived(address indexed sender, uint256 value);
          /// @dev Fallback function accepts Ether transactions.
          receive() external payable {
              emit SafeReceived(msg.sender, msg.value);
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title SecuredTokenTransfer - Secure token transfer
      /// @author Richard Meissner - <[email protected]>
      contract SecuredTokenTransfer {
          /// @dev Transfers a token and returns if it was a success
          /// @param token Token that should be transferred
          /// @param receiver Receiver to whom the token should be transferred
          /// @param amount The amount of tokens that should be transferred
          function transferToken(
              address token,
              address receiver,
              uint256 amount
          ) internal returns (bool transferred) {
              // 0xa9059cbb - keccack("transfer(address,uint256)")
              bytes memory data = abi.encodeWithSelector(0xa9059cbb, receiver, amount);
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  // We write the return value to scratch space.
                  // See https://docs.soliditylang.org/en/v0.7.6/internals/layout_in_memory.html#layout-in-memory
                  let success := call(sub(gas(), 10000), token, 0, add(data, 0x20), mload(data), 0, 0x20)
                  switch returndatasize()
                      case 0 {
                          transferred := success
                      }
                      case 0x20 {
                          transferred := iszero(or(iszero(success), iszero(mload(0))))
                      }
                      default {
                          transferred := 0
                      }
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title SelfAuthorized - authorizes current contract to perform actions
      /// @author Richard Meissner - <[email protected]>
      contract SelfAuthorized {
          function requireSelfCall() private view {
              require(msg.sender == address(this), "GS031");
          }
          modifier authorized() {
              // This is a function call as it minimized the bytecode size
              requireSelfCall();
              _;
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title SignatureDecoder - Decodes signatures that a encoded as bytes
      /// @author Richard Meissner - <[email protected]>
      contract SignatureDecoder {
          /// @dev divides bytes signature into `uint8 v, bytes32 r, bytes32 s`.
          /// @notice Make sure to peform a bounds check for @param pos, to avoid out of bounds access on @param signatures
          /// @param pos which signature to read. A prior bounds check of this parameter should be performed, to avoid out of bounds access
          /// @param signatures concatenated rsv signatures
          function signatureSplit(bytes memory signatures, uint256 pos)
              internal
              pure
              returns (
                  uint8 v,
                  bytes32 r,
                  bytes32 s
              )
          {
              // The signature format is a compact form of:
              //   {bytes32 r}{bytes32 s}{uint8 v}
              // Compact means, uint8 is not padded to 32 bytes.
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  let signaturePos := mul(0x41, pos)
                  r := mload(add(signatures, add(signaturePos, 0x20)))
                  s := mload(add(signatures, add(signaturePos, 0x40)))
                  // Here we are loading the last 32 bytes, including 31 bytes
                  // of 's'. There is no 'mload8' to do this.
                  //
                  // 'byte' is not working due to the Solidity parser, so lets
                  // use the second best option, 'and'
                  v := and(mload(add(signatures, add(signaturePos, 0x41))), 0xff)
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title Singleton - Base for singleton contracts (should always be first super contract)
      ///         This contract is tightly coupled to our proxy contract (see `proxies/GnosisSafeProxy.sol`)
      /// @author Richard Meissner - <[email protected]>
      contract Singleton {
          // singleton always needs to be first declared variable, to ensure that it is at the same location as in the Proxy contract.
          // It should also always be ensured that the address is stored alone (uses a full word)
          address private singleton;
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /// @title StorageAccessible - generic base contract that allows callers to access all internal storage.
      /// @notice See https://github.com/gnosis/util-contracts/blob/bb5fe5fb5df6d8400998094fb1b32a178a47c3a1/contracts/StorageAccessible.sol
      contract StorageAccessible {
          /**
           * @dev Reads `length` bytes of storage in the currents contract
           * @param offset - the offset in the current contract's storage in words to start reading from
           * @param length - the number of words (32 bytes) of data to read
           * @return the bytes that were read.
           */
          function getStorageAt(uint256 offset, uint256 length) public view returns (bytes memory) {
              bytes memory result = new bytes(length * 32);
              for (uint256 index = 0; index < length; index++) {
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      let word := sload(add(offset, index))
                      mstore(add(add(result, 0x20), mul(index, 0x20)), word)
                  }
              }
              return result;
          }
          /**
           * @dev Performs a delegetecall on a targetContract in the context of self.
           * Internally reverts execution to avoid side effects (making it static).
           *
           * This method reverts with data equal to `abi.encode(bool(success), bytes(response))`.
           * Specifically, the `returndata` after a call to this method will be:
           * `success:bool || response.length:uint256 || response:bytes`.
           *
           * @param targetContract Address of the contract containing the code to execute.
           * @param calldataPayload Calldata that should be sent to the target contract (encoded method name and arguments).
           */
          function simulateAndRevert(address targetContract, bytes memory calldataPayload) external {
              // solhint-disable-next-line no-inline-assembly
              assembly {
                  let success := delegatecall(gas(), targetContract, add(calldataPayload, 0x20), mload(calldataPayload), 0, 0)
                  mstore(0x00, success)
                  mstore(0x20, returndatasize())
                  returndatacopy(0x40, 0, returndatasize())
                  revert(0, add(returndatasize(), 0x40))
              }
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      /**
       * @title GnosisSafeMath
       * @dev Math operations with safety checks that revert on error
       * Renamed from SafeMath to GnosisSafeMath to avoid conflicts
       * TODO: remove once open zeppelin update to solc 0.5.0
       */
      library GnosisSafeMath {
          /**
           * @dev Multiplies two numbers, reverts on overflow.
           */
          function mul(uint256 a, uint256 b) internal pure returns (uint256) {
              // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
              // benefit is lost if 'b' is also tested.
              // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
              if (a == 0) {
                  return 0;
              }
              uint256 c = a * b;
              require(c / a == b);
              return c;
          }
          /**
           * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
           */
          function sub(uint256 a, uint256 b) internal pure returns (uint256) {
              require(b <= a);
              uint256 c = a - b;
              return c;
          }
          /**
           * @dev Adds two numbers, reverts on overflow.
           */
          function add(uint256 a, uint256 b) internal pure returns (uint256) {
              uint256 c = a + b;
              require(c >= a);
              return c;
          }
          /**
           * @dev Returns the largest of two numbers.
           */
          function max(uint256 a, uint256 b) internal pure returns (uint256) {
              return a >= b ? a : b;
          }
      }
      // SPDX-License-Identifier: LGPL-3.0-only
      pragma solidity >=0.7.0 <0.9.0;
      contract ISignatureValidatorConstants {
          // bytes4(keccak256("isValidSignature(bytes,bytes)")
          bytes4 internal constant EIP1271_MAGIC_VALUE = 0x20c13b0b;
      }
      abstract contract ISignatureValidator is ISignatureValidatorConstants {
          /**
           * @dev Should return whether the signature provided is valid for the provided data
           * @param _data Arbitrary length data signed on the behalf of address(this)
           * @param _signature Signature byte array associated with _data
           *
           * MUST return the bytes4 magic value 0x20c13b0b when function passes.
           * MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
           * MUST allow external calls
           */
          function isValidSignature(bytes memory _data, bytes memory _signature) public view virtual returns (bytes4);
      }