ETH Price: $2,107.69 (+1.40%)

Transaction Decoder

Block:
21486576 at Dec-26-2024 12:15:47 PM +UTC
Transaction Fee:
0.000885156340924584 ETH $1.87
Gas Used:
118,674 Gas / 7.458721716 Gwei

Execution Trace

TransferHelper.bulkTransfer( items=, conduitKey=0000007B02230091A7ED01230072F7006A004D60A8D4E71D599B8104250F0000 ) => ( items=, conduitKey= )
  • OpenSea: Conduit.4ce34aa2( )
    • DefimonsApartments.transferFrom( from=0x3D91925C094028e6c20eA8c37A156382eA02e16E, to=0x214F85FcAeea5930e090571FE1E7873CF851cBa9, tokenId=1354 )
    • DefimonsApartments.transferFrom( from=0x3D91925C094028e6c20eA8c37A156382eA02e16E, to=0x214F85FcAeea5930e090571FE1E7873CF851cBa9, tokenId=1467 )
    • DefimonsApartments.transferFrom( from=0x3D91925C094028e6c20eA8c37A156382eA02e16E, to=0x214F85FcAeea5930e090571FE1E7873CF851cBa9, tokenId=2148 )
    • DefimonsApartments.transferFrom( from=0x3D91925C094028e6c20eA8c37A156382eA02e16E, to=0x214F85FcAeea5930e090571FE1E7873CF851cBa9, tokenId=2592 )
    • DefimonsApartments.transferFrom( from=0x3D91925C094028e6c20eA8c37A156382eA02e16E, to=0x214F85FcAeea5930e090571FE1E7873CF851cBa9, tokenId=2661 )
      bulkTransfer[TransferHelper (ln:57)]
      File 1 of 2: TransferHelper
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import { IERC721Receiver } from "../interfaces/IERC721Receiver.sol";
      import "./TransferHelperStructs.sol";
      import { ConduitInterface } from "../interfaces/ConduitInterface.sol";
      import {
          ConduitControllerInterface
      } from "../interfaces/ConduitControllerInterface.sol";
      import { Conduit } from "../conduit/Conduit.sol";
      import { ConduitTransfer } from "../conduit/lib/ConduitStructs.sol";
      import {
          TransferHelperInterface
      } from "../interfaces/TransferHelperInterface.sol";
      import { TransferHelperErrors } from "../interfaces/TransferHelperErrors.sol";
      /**
       * @title TransferHelper
       * @author stephankmin, stuckinaboot, ryanio
       * @notice TransferHelper is a utility contract for transferring
       *         ERC20/ERC721/ERC1155 items in bulk to specific recipients.
       */
      contract TransferHelper is TransferHelperInterface, TransferHelperErrors {
          // Allow for interaction with the conduit controller.
          ConduitControllerInterface internal immutable _CONDUIT_CONTROLLER;
          // Set conduit creation code and runtime code hashes as immutable arguments.
          bytes32 internal immutable _CONDUIT_CREATION_CODE_HASH;
          bytes32 internal immutable _CONDUIT_RUNTIME_CODE_HASH;
          /**
           * @dev Set the supplied conduit controller and retrieve its
           *      conduit creation code hash.
           *
           *
           * @param conduitController A contract that deploys conduits, or proxies
           *                          that may optionally be used to transfer approved
           *                          ERC20/721/1155 tokens.
           */
          constructor(address conduitController) {
              // Get the conduit creation code and runtime code hashes from the
              // supplied conduit controller and set them as an immutable.
              ConduitControllerInterface controller = ConduitControllerInterface(
                  conduitController
              );
              (_CONDUIT_CREATION_CODE_HASH, _CONDUIT_RUNTIME_CODE_HASH) = controller
                  .getConduitCodeHashes();
              // Set the supplied conduit controller as an immutable.
              _CONDUIT_CONTROLLER = controller;
          }
          /**
           * @notice Transfer multiple ERC20/ERC721/ERC1155 items to
           *         specified recipients.
           *
           * @param items      The items to transfer to an intended recipient.
           * @param conduitKey An optional conduit key referring to a conduit through
           *                   which the bulk transfer should occur.
           *
           * @return magicValue A value indicating that the transfers were successful.
           */
          function bulkTransfer(
              TransferHelperItemsWithRecipient[] calldata items,
              bytes32 conduitKey
          ) external override returns (bytes4 magicValue) {
              // Ensure that a conduit key has been supplied.
              if (conduitKey == bytes32(0)) {
                  revert InvalidConduit(conduitKey, address(0));
              }
              // Use conduit derived from supplied conduit key to perform transfers.
              _performTransfersWithConduit(items, conduitKey);
              // Return a magic value indicating that the transfers were performed.
              magicValue = this.bulkTransfer.selector;
          }
          /**
           * @notice Perform multiple transfers to specified recipients via the
           *         conduit derived from the provided conduit key.
           *
           * @param transfers  The items to transfer.
           * @param conduitKey The conduit key referring to the conduit through
           *                   which the bulk transfer should occur.
           */
          function _performTransfersWithConduit(
              TransferHelperItemsWithRecipient[] calldata transfers,
              bytes32 conduitKey
          ) internal {
              // Retrieve total number of transfers and place on stack.
              uint256 numTransfers = transfers.length;
              // Derive the conduit address from the deployer, conduit key
              // and creation code hash.
              address conduit = address(
                  uint160(
                      uint256(
                          keccak256(
                              abi.encodePacked(
                                  bytes1(0xff),
                                  address(_CONDUIT_CONTROLLER),
                                  conduitKey,
                                  _CONDUIT_CREATION_CODE_HASH
                              )
                          )
                      )
                  )
              );
              // Declare a variable to store the sum of all items across transfers.
              uint256 sumOfItemsAcrossAllTransfers;
              // Skip overflow checks: all for loops are indexed starting at zero.
              unchecked {
                  // Iterate over each transfer.
                  for (uint256 i = 0; i < numTransfers; ++i) {
                      // Retrieve the transfer in question.
                      TransferHelperItemsWithRecipient calldata transfer = transfers[
                          i
                      ];
                      // Increment totalItems by the number of items in the transfer.
                      sumOfItemsAcrossAllTransfers += transfer.items.length;
                  }
              }
              // Declare a new array in memory with length totalItems to populate with
              // each conduit transfer.
              ConduitTransfer[] memory conduitTransfers = new ConduitTransfer[](
                  sumOfItemsAcrossAllTransfers
              );
              // Declare an index for storing ConduitTransfers in conduitTransfers.
              uint256 itemIndex;
              // Skip overflow checks: all for loops are indexed starting at zero.
              unchecked {
                  // Iterate over each transfer.
                  for (uint256 i = 0; i < numTransfers; ++i) {
                      // Retrieve the transfer in question.
                      TransferHelperItemsWithRecipient calldata transfer = transfers[
                          i
                      ];
                      // Retrieve the items of the transfer in question.
                      TransferHelperItem[] calldata transferItems = transfer.items;
                      // Ensure recipient is not the zero address.
                      _checkRecipientIsNotZeroAddress(transfer.recipient);
                      // Create a boolean indicating whether validateERC721Receiver
                      // is true and recipient is a contract.
                      bool callERC721Receiver = transfer.validateERC721Receiver &&
                          transfer.recipient.code.length != 0;
                      // Retrieve the total number of items in the transfer and
                      // place on stack.
                      uint256 numItemsInTransfer = transferItems.length;
                      // Iterate over each item in the transfer to create a
                      // corresponding ConduitTransfer.
                      for (uint256 j = 0; j < numItemsInTransfer; ++j) {
                          // Retrieve the item from the transfer.
                          TransferHelperItem calldata item = transferItems[j];
                          if (item.itemType == ConduitItemType.ERC20) {
                              // Ensure that the identifier of an ERC20 token is 0.
                              if (item.identifier != 0) {
                                  revert InvalidERC20Identifier();
                              }
                          }
                          // If the item is an ERC721 token and
                          // callERC721Receiver is true...
                          if (item.itemType == ConduitItemType.ERC721) {
                              if (callERC721Receiver) {
                                  // Check if the recipient implements
                                  // onERC721Received for the given tokenId.
                                  _checkERC721Receiver(
                                      conduit,
                                      transfer.recipient,
                                      item.identifier
                                  );
                              }
                          }
                          // Create a ConduitTransfer corresponding to each
                          // TransferHelperItem.
                          conduitTransfers[itemIndex] = ConduitTransfer(
                              item.itemType,
                              item.token,
                              msg.sender,
                              transfer.recipient,
                              item.identifier,
                              item.amount
                          );
                          // Increment the index for storing ConduitTransfers.
                          ++itemIndex;
                      }
                  }
              }
              // Attempt the external call to transfer tokens via the derived conduit.
              try ConduitInterface(conduit).execute(conduitTransfers) returns (
                  bytes4 conduitMagicValue
              ) {
                  // Check if the value returned from the external call matches
                  // the conduit `execute` selector.
                  if (conduitMagicValue != ConduitInterface.execute.selector) {
                      // If the external call fails, revert with the conduit key
                      // and conduit address.
                      revert InvalidConduit(conduitKey, conduit);
                  }
              } catch Error(string memory reason) {
                  // Catch reverts with a provided reason string and
                  // revert with the reason, conduit key and conduit address.
                  revert ConduitErrorRevertString(reason, conduitKey, conduit);
              } catch (bytes memory data) {
                  // Conduits will throw a custom error when attempting to transfer
                  // native token item types or an ERC721 item amount other than 1.
                  // Bubble up these custom errors when encountered. Note that the
                  // conduit itself will bubble up revert reasons from transfers as
                  // well, meaning that these errors are not necessarily indicative of
                  // an issue with the item type or amount in cases where the same
                  // custom error signature is encountered during a conduit transfer.
                  // Set initial value of first four bytes of revert data to the mask.
                  bytes4 customErrorSelector = bytes4(0xffffffff);
                  // Utilize assembly to read first four bytes (if present) directly.
                  assembly {
                      // Combine original mask with first four bytes of revert data.
                      customErrorSelector := and(
                          mload(add(data, 0x20)), // Data begins after length offset.
                          customErrorSelector
                      )
                  }
                  // Pass through the custom error in question if the revert data is
                  // the correct length and matches an expected custom error selector.
                  if (
                      data.length == 4 &&
                      (customErrorSelector == InvalidItemType.selector ||
                          customErrorSelector == InvalidERC721TransferAmount.selector)
                  ) {
                      // "Bubble up" the revert reason.
                      assembly {
                          revert(add(data, 0x20), 0x04)
                      }
                  }
                  // Catch all other reverts from the external call to the conduit and
                  // include the conduit's raw revert reason as a data argument to a
                  // new custom error.
                  revert ConduitErrorRevertBytes(data, conduitKey, conduit);
              }
          }
          /**
           * @notice An internal function to check if a recipient address implements
           *         onERC721Received for a given tokenId. Note that this check does
           *         not adhere to the safe transfer specification and is only meant
           *         to provide an additional layer of assurance that the recipient
           *         can receive the tokens — any hooks or post-transfer checks will
           *         fail and the caller will be the transfer helper rather than the
           *         ERC721 contract. Note that the conduit is set as the operator, as
           *         it will be the caller once the transfer is performed.
           *
           * @param conduit   The conduit to provide as the operator when calling
           *                  onERC721Received.
           * @param recipient The ERC721 recipient on which to call onERC721Received.
           * @param tokenId   The ERC721 tokenId of the token being transferred.
           */
          function _checkERC721Receiver(
              address conduit,
              address recipient,
              uint256 tokenId
          ) internal {
              // Check if recipient can receive ERC721 tokens.
              try
                  IERC721Receiver(recipient).onERC721Received(
                      conduit,
                      msg.sender,
                      tokenId,
                      ""
                  )
              returns (bytes4 selector) {
                  // Check if onERC721Received selector is valid.
                  if (selector != IERC721Receiver.onERC721Received.selector) {
                      // Revert if recipient cannot accept
                      // ERC721 tokens.
                      revert InvalidERC721Recipient(recipient);
                  }
              } catch (bytes memory data) {
                  // "Bubble up" recipient's revert reason.
                  revert ERC721ReceiverErrorRevertBytes(
                      data,
                      recipient,
                      msg.sender,
                      tokenId
                  );
              } catch Error(string memory reason) {
                  // "Bubble up" recipient's revert reason.
                  revert ERC721ReceiverErrorRevertString(
                      reason,
                      recipient,
                      msg.sender,
                      tokenId
                  );
              }
          }
          /**
           * @notice An internal function that reverts if the passed-in recipient
           *         is the zero address.
           *
           * @param recipient The recipient on which to perform the check.
           */
          function _checkRecipientIsNotZeroAddress(address recipient) internal pure {
              // Revert if the recipient is the zero address.
              if (recipient == address(0x0)) {
                  revert RecipientCannotBeZeroAddress();
              }
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      interface IERC721Receiver {
          function onERC721Received(
              address operator,
              address from,
              uint256 tokenId,
              bytes calldata data
          ) external returns (bytes4);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import { ConduitItemType } from "../conduit/lib/ConduitEnums.sol";
      /**
       * @dev A TransferHelperItem specifies the itemType (ERC20/ERC721/ERC1155),
       *      token address, token identifier, and amount of the token to be
       *      transferred via the TransferHelper. For ERC20 tokens, identifier
       *      must be 0. For ERC721 tokens, amount must be 1.
       */
      struct TransferHelperItem {
          ConduitItemType itemType;
          address token;
          uint256 identifier;
          uint256 amount;
      }
      /**
       * @dev A TransferHelperItemsWithRecipient specifies the tokens to transfer
       *      via the TransferHelper, their intended recipient, and a boolean flag
       *      indicating whether onERC721Received should be called on a recipient
       *      contract.
       */
      struct TransferHelperItemsWithRecipient {
          TransferHelperItem[] items;
          address recipient;
          bool validateERC721Receiver;
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import {
          ConduitTransfer,
          ConduitBatch1155Transfer
      } from "../conduit/lib/ConduitStructs.sol";
      /**
       * @title ConduitInterface
       * @author 0age
       * @notice ConduitInterface contains all external function interfaces, events,
       *         and errors for conduit contracts.
       */
      interface ConduitInterface {
          /**
           * @dev Revert with an error when attempting to execute transfers using a
           *      caller that does not have an open channel.
           */
          error ChannelClosed(address channel);
          /**
           * @dev Revert with an error when attempting to update a channel to the
           *      current status of that channel.
           */
          error ChannelStatusAlreadySet(address channel, bool isOpen);
          /**
           * @dev Revert with an error when attempting to execute a transfer for an
           *      item that does not have an ERC20/721/1155 item type.
           */
          error InvalidItemType();
          /**
           * @dev Revert with an error when attempting to update the status of a
           *      channel from a caller that is not the conduit controller.
           */
          error InvalidController();
          /**
           * @dev Emit an event whenever a channel is opened or closed.
           *
           * @param channel The channel that has been updated.
           * @param open    A boolean indicating whether the conduit is open or not.
           */
          event ChannelUpdated(address indexed channel, bool open);
          /**
           * @notice Execute a sequence of ERC20/721/1155 transfers. Only a caller
           *         with an open channel can call this function.
           *
           * @param transfers The ERC20/721/1155 transfers to perform.
           *
           * @return magicValue A magic value indicating that the transfers were
           *                    performed successfully.
           */
          function execute(ConduitTransfer[] calldata transfers)
              external
              returns (bytes4 magicValue);
          /**
           * @notice Execute a sequence of batch 1155 transfers. Only a caller with an
           *         open channel can call this function.
           *
           * @param batch1155Transfers The 1155 batch transfers to perform.
           *
           * @return magicValue A magic value indicating that the transfers were
           *                    performed successfully.
           */
          function executeBatch1155(
              ConduitBatch1155Transfer[] calldata batch1155Transfers
          ) external returns (bytes4 magicValue);
          /**
           * @notice Execute a sequence of transfers, both single and batch 1155. Only
           *         a caller with an open channel can call this function.
           *
           * @param standardTransfers  The ERC20/721/1155 transfers to perform.
           * @param batch1155Transfers The 1155 batch transfers to perform.
           *
           * @return magicValue A magic value indicating that the transfers were
           *                    performed successfully.
           */
          function executeWithBatch1155(
              ConduitTransfer[] calldata standardTransfers,
              ConduitBatch1155Transfer[] calldata batch1155Transfers
          ) external returns (bytes4 magicValue);
          /**
           * @notice Open or close a given channel. Only callable by the controller.
           *
           * @param channel The channel to open or close.
           * @param isOpen  The status of the channel (either open or closed).
           */
          function updateChannel(address channel, bool isOpen) external;
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      /**
       * @title ConduitControllerInterface
       * @author 0age
       * @notice ConduitControllerInterface contains all external function interfaces,
       *         structs, events, and errors for the conduit controller.
       */
      interface ConduitControllerInterface {
          /**
           * @dev Track the conduit key, current owner, new potential owner, and open
           *      channels for each deployed conduit.
           */
          struct ConduitProperties {
              bytes32 key;
              address owner;
              address potentialOwner;
              address[] channels;
              mapping(address => uint256) channelIndexesPlusOne;
          }
          /**
           * @dev Emit an event whenever a new conduit is created.
           *
           * @param conduit    The newly created conduit.
           * @param conduitKey The conduit key used to create the new conduit.
           */
          event NewConduit(address conduit, bytes32 conduitKey);
          /**
           * @dev Emit an event whenever conduit ownership is transferred.
           *
           * @param conduit       The conduit for which ownership has been
           *                      transferred.
           * @param previousOwner The previous owner of the conduit.
           * @param newOwner      The new owner of the conduit.
           */
          event OwnershipTransferred(
              address indexed conduit,
              address indexed previousOwner,
              address indexed newOwner
          );
          /**
           * @dev Emit an event whenever a conduit owner registers a new potential
           *      owner for that conduit.
           *
           * @param newPotentialOwner The new potential owner of the conduit.
           */
          event PotentialOwnerUpdated(address indexed newPotentialOwner);
          /**
           * @dev Revert with an error when attempting to create a new conduit using a
           *      conduit key where the first twenty bytes of the key do not match the
           *      address of the caller.
           */
          error InvalidCreator();
          /**
           * @dev Revert with an error when attempting to create a new conduit when no
           *      initial owner address is supplied.
           */
          error InvalidInitialOwner();
          /**
           * @dev Revert with an error when attempting to set a new potential owner
           *      that is already set.
           */
          error NewPotentialOwnerAlreadySet(
              address conduit,
              address newPotentialOwner
          );
          /**
           * @dev Revert with an error when attempting to cancel ownership transfer
           *      when no new potential owner is currently set.
           */
          error NoPotentialOwnerCurrentlySet(address conduit);
          /**
           * @dev Revert with an error when attempting to interact with a conduit that
           *      does not yet exist.
           */
          error NoConduit();
          /**
           * @dev Revert with an error when attempting to create a conduit that
           *      already exists.
           */
          error ConduitAlreadyExists(address conduit);
          /**
           * @dev Revert with an error when attempting to update channels or transfer
           *      ownership of a conduit when the caller is not the owner of the
           *      conduit in question.
           */
          error CallerIsNotOwner(address conduit);
          /**
           * @dev Revert with an error when attempting to register a new potential
           *      owner and supplying the null address.
           */
          error NewPotentialOwnerIsZeroAddress(address conduit);
          /**
           * @dev Revert with an error when attempting to claim ownership of a conduit
           *      with a caller that is not the current potential owner for the
           *      conduit in question.
           */
          error CallerIsNotNewPotentialOwner(address conduit);
          /**
           * @dev Revert with an error when attempting to retrieve a channel using an
           *      index that is out of range.
           */
          error ChannelOutOfRange(address conduit);
          /**
           * @notice Deploy a new conduit using a supplied conduit key and assigning
           *         an initial owner for the deployed conduit. Note that the first
           *         twenty bytes of the supplied conduit key must match the caller
           *         and that a new conduit cannot be created if one has already been
           *         deployed using the same conduit key.
           *
           * @param conduitKey   The conduit key used to deploy the conduit. Note that
           *                     the first twenty bytes of the conduit key must match
           *                     the caller of this contract.
           * @param initialOwner The initial owner to set for the new conduit.
           *
           * @return conduit The address of the newly deployed conduit.
           */
          function createConduit(bytes32 conduitKey, address initialOwner)
              external
              returns (address conduit);
          /**
           * @notice Open or close a channel on a given conduit, thereby allowing the
           *         specified account to execute transfers against that conduit.
           *         Extreme care must be taken when updating channels, as malicious
           *         or vulnerable channels can transfer any ERC20, ERC721 and ERC1155
           *         tokens where the token holder has granted the conduit approval.
           *         Only the owner of the conduit in question may call this function.
           *
           * @param conduit The conduit for which to open or close the channel.
           * @param channel The channel to open or close on the conduit.
           * @param isOpen  A boolean indicating whether to open or close the channel.
           */
          function updateChannel(
              address conduit,
              address channel,
              bool isOpen
          ) external;
          /**
           * @notice Initiate conduit ownership transfer by assigning a new potential
           *         owner for the given conduit. Once set, the new potential owner
           *         may call `acceptOwnership` to claim ownership of the conduit.
           *         Only the owner of the conduit in question may call this function.
           *
           * @param conduit The conduit for which to initiate ownership transfer.
           * @param newPotentialOwner The new potential owner of the conduit.
           */
          function transferOwnership(address conduit, address newPotentialOwner)
              external;
          /**
           * @notice Clear the currently set potential owner, if any, from a conduit.
           *         Only the owner of the conduit in question may call this function.
           *
           * @param conduit The conduit for which to cancel ownership transfer.
           */
          function cancelOwnershipTransfer(address conduit) external;
          /**
           * @notice Accept ownership of a supplied conduit. Only accounts that the
           *         current owner has set as the new potential owner may call this
           *         function.
           *
           * @param conduit The conduit for which to accept ownership.
           */
          function acceptOwnership(address conduit) external;
          /**
           * @notice Retrieve the current owner of a deployed conduit.
           *
           * @param conduit The conduit for which to retrieve the associated owner.
           *
           * @return owner The owner of the supplied conduit.
           */
          function ownerOf(address conduit) external view returns (address owner);
          /**
           * @notice Retrieve the conduit key for a deployed conduit via reverse
           *         lookup.
           *
           * @param conduit The conduit for which to retrieve the associated conduit
           *                key.
           *
           * @return conduitKey The conduit key used to deploy the supplied conduit.
           */
          function getKey(address conduit) external view returns (bytes32 conduitKey);
          /**
           * @notice Derive the conduit associated with a given conduit key and
           *         determine whether that conduit exists (i.e. whether it has been
           *         deployed).
           *
           * @param conduitKey The conduit key used to derive the conduit.
           *
           * @return conduit The derived address of the conduit.
           * @return exists  A boolean indicating whether the derived conduit has been
           *                 deployed or not.
           */
          function getConduit(bytes32 conduitKey)
              external
              view
              returns (address conduit, bool exists);
          /**
           * @notice Retrieve the potential owner, if any, for a given conduit. The
           *         current owner may set a new potential owner via
           *         `transferOwnership` and that owner may then accept ownership of
           *         the conduit in question via `acceptOwnership`.
           *
           * @param conduit The conduit for which to retrieve the potential owner.
           *
           * @return potentialOwner The potential owner, if any, for the conduit.
           */
          function getPotentialOwner(address conduit)
              external
              view
              returns (address potentialOwner);
          /**
           * @notice Retrieve the status (either open or closed) of a given channel on
           *         a conduit.
           *
           * @param conduit The conduit for which to retrieve the channel status.
           * @param channel The channel for which to retrieve the status.
           *
           * @return isOpen The status of the channel on the given conduit.
           */
          function getChannelStatus(address conduit, address channel)
              external
              view
              returns (bool isOpen);
          /**
           * @notice Retrieve the total number of open channels for a given conduit.
           *
           * @param conduit The conduit for which to retrieve the total channel count.
           *
           * @return totalChannels The total number of open channels for the conduit.
           */
          function getTotalChannels(address conduit)
              external
              view
              returns (uint256 totalChannels);
          /**
           * @notice Retrieve an open channel at a specific index for a given conduit.
           *         Note that the index of a channel can change as a result of other
           *         channels being closed on the conduit.
           *
           * @param conduit      The conduit for which to retrieve the open channel.
           * @param channelIndex The index of the channel in question.
           *
           * @return channel The open channel, if any, at the specified channel index.
           */
          function getChannel(address conduit, uint256 channelIndex)
              external
              view
              returns (address channel);
          /**
           * @notice Retrieve all open channels for a given conduit. Note that calling
           *         this function for a conduit with many channels will revert with
           *         an out-of-gas error.
           *
           * @param conduit The conduit for which to retrieve open channels.
           *
           * @return channels An array of open channels on the given conduit.
           */
          function getChannels(address conduit)
              external
              view
              returns (address[] memory channels);
          /**
           * @dev Retrieve the conduit creation code and runtime code hashes.
           */
          function getConduitCodeHashes()
              external
              view
              returns (bytes32 creationCodeHash, bytes32 runtimeCodeHash);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import { ConduitInterface } from "../interfaces/ConduitInterface.sol";
      import { ConduitItemType } from "./lib/ConduitEnums.sol";
      import { TokenTransferrer } from "../lib/TokenTransferrer.sol";
      import {
          ConduitTransfer,
          ConduitBatch1155Transfer
      } from "./lib/ConduitStructs.sol";
      import "./lib/ConduitConstants.sol";
      /**
       * @title Conduit
       * @author 0age
       * @notice This contract serves as an originator for "proxied" transfers. Each
       *         conduit is deployed and controlled by a "conduit controller" that can
       *         add and remove "channels" or contracts that can instruct the conduit
       *         to transfer approved ERC20/721/1155 tokens. *IMPORTANT NOTE: each
       *         conduit has an owner that can arbitrarily add or remove channels, and
       *         a malicious or negligent owner can add a channel that allows for any
       *         approved ERC20/721/1155 tokens to be taken immediately — be extremely
       *         cautious with what conduits you give token approvals to!*
       */
      contract Conduit is ConduitInterface, TokenTransferrer {
          // Set deployer as an immutable controller that can update channel statuses.
          address private immutable _controller;
          // Track the status of each channel.
          mapping(address => bool) private _channels;
          /**
           * @notice Ensure that the caller is currently registered as an open channel
           *         on the conduit.
           */
          modifier onlyOpenChannel() {
              // Utilize assembly to access channel storage mapping directly.
              assembly {
                  // Write the caller to scratch space.
                  mstore(ChannelKey_channel_ptr, caller())
                  // Write the storage slot for _channels to scratch space.
                  mstore(ChannelKey_slot_ptr, _channels.slot)
                  // Derive the position in storage of _channels[msg.sender]
                  // and check if the stored value is zero.
                  if iszero(
                      sload(keccak256(ChannelKey_channel_ptr, ChannelKey_length))
                  ) {
                      // The caller is not an open channel; revert with
                      // ChannelClosed(caller). First, set error signature in memory.
                      mstore(ChannelClosed_error_ptr, ChannelClosed_error_signature)
                      // Next, set the caller as the argument.
                      mstore(ChannelClosed_channel_ptr, caller())
                      // Finally, revert, returning full custom error with argument.
                      revert(ChannelClosed_error_ptr, ChannelClosed_error_length)
                  }
              }
              // Continue with function execution.
              _;
          }
          /**
           * @notice In the constructor, set the deployer as the controller.
           */
          constructor() {
              // Set the deployer as the controller.
              _controller = msg.sender;
          }
          /**
           * @notice Execute a sequence of ERC20/721/1155 transfers. Only a caller
           *         with an open channel can call this function. Note that channels
           *         are expected to implement reentrancy protection if desired, and
           *         that cross-channel reentrancy may be possible if the conduit has
           *         multiple open channels at once. Also note that channels are
           *         expected to implement checks against transferring any zero-amount
           *         items if that constraint is desired.
           *
           * @param transfers The ERC20/721/1155 transfers to perform.
           *
           * @return magicValue A magic value indicating that the transfers were
           *                    performed successfully.
           */
          function execute(ConduitTransfer[] calldata transfers)
              external
              override
              onlyOpenChannel
              returns (bytes4 magicValue)
          {
              // Retrieve the total number of transfers and place on the stack.
              uint256 totalStandardTransfers = transfers.length;
              // Iterate over each transfer.
              for (uint256 i = 0; i < totalStandardTransfers; ) {
                  // Retrieve the transfer in question and perform the transfer.
                  _transfer(transfers[i]);
                  // Skip overflow check as for loop is indexed starting at zero.
                  unchecked {
                      ++i;
                  }
              }
              // Return a magic value indicating that the transfers were performed.
              magicValue = this.execute.selector;
          }
          /**
           * @notice Execute a sequence of batch 1155 item transfers. Only a caller
           *         with an open channel can call this function. Note that channels
           *         are expected to implement reentrancy protection if desired, and
           *         that cross-channel reentrancy may be possible if the conduit has
           *         multiple open channels at once. Also note that channels are
           *         expected to implement checks against transferring any zero-amount
           *         items if that constraint is desired.
           *
           * @param batchTransfers The 1155 batch item transfers to perform.
           *
           * @return magicValue A magic value indicating that the item transfers were
           *                    performed successfully.
           */
          function executeBatch1155(
              ConduitBatch1155Transfer[] calldata batchTransfers
          ) external override onlyOpenChannel returns (bytes4 magicValue) {
              // Perform 1155 batch transfers. Note that memory should be considered
              // entirely corrupted from this point forward.
              _performERC1155BatchTransfers(batchTransfers);
              // Return a magic value indicating that the transfers were performed.
              magicValue = this.executeBatch1155.selector;
          }
          /**
           * @notice Execute a sequence of transfers, both single ERC20/721/1155 item
           *         transfers as well as batch 1155 item transfers. Only a caller
           *         with an open channel can call this function. Note that channels
           *         are expected to implement reentrancy protection if desired, and
           *         that cross-channel reentrancy may be possible if the conduit has
           *         multiple open channels at once. Also note that channels are
           *         expected to implement checks against transferring any zero-amount
           *         items if that constraint is desired.
           *
           * @param standardTransfers The ERC20/721/1155 item transfers to perform.
           * @param batchTransfers    The 1155 batch item transfers to perform.
           *
           * @return magicValue A magic value indicating that the item transfers were
           *                    performed successfully.
           */
          function executeWithBatch1155(
              ConduitTransfer[] calldata standardTransfers,
              ConduitBatch1155Transfer[] calldata batchTransfers
          ) external override onlyOpenChannel returns (bytes4 magicValue) {
              // Retrieve the total number of transfers and place on the stack.
              uint256 totalStandardTransfers = standardTransfers.length;
              // Iterate over each standard transfer.
              for (uint256 i = 0; i < totalStandardTransfers; ) {
                  // Retrieve the transfer in question and perform the transfer.
                  _transfer(standardTransfers[i]);
                  // Skip overflow check as for loop is indexed starting at zero.
                  unchecked {
                      ++i;
                  }
              }
              // Perform 1155 batch transfers. Note that memory should be considered
              // entirely corrupted from this point forward aside from the free memory
              // pointer having the default value.
              _performERC1155BatchTransfers(batchTransfers);
              // Return a magic value indicating that the transfers were performed.
              magicValue = this.executeWithBatch1155.selector;
          }
          /**
           * @notice Open or close a given channel. Only callable by the controller.
           *
           * @param channel The channel to open or close.
           * @param isOpen  The status of the channel (either open or closed).
           */
          function updateChannel(address channel, bool isOpen) external override {
              // Ensure that the caller is the controller of this contract.
              if (msg.sender != _controller) {
                  revert InvalidController();
              }
              // Ensure that the channel does not already have the indicated status.
              if (_channels[channel] == isOpen) {
                  revert ChannelStatusAlreadySet(channel, isOpen);
              }
              // Update the status of the channel.
              _channels[channel] = isOpen;
              // Emit a corresponding event.
              emit ChannelUpdated(channel, isOpen);
          }
          /**
           * @dev Internal function to transfer a given ERC20/721/1155 item. Note that
           *      channels are expected to implement checks against transferring any
           *      zero-amount items if that constraint is desired.
           *
           * @param item The ERC20/721/1155 item to transfer.
           */
          function _transfer(ConduitTransfer calldata item) internal {
              // Determine the transfer method based on the respective item type.
              if (item.itemType == ConduitItemType.ERC20) {
                  // Transfer ERC20 token. Note that item.identifier is ignored and
                  // therefore ERC20 transfer items are potentially malleable — this
                  // check should be performed by the calling channel if a constraint
                  // on item malleability is desired.
                  _performERC20Transfer(item.token, item.from, item.to, item.amount);
              } else if (item.itemType == ConduitItemType.ERC721) {
                  // Ensure that exactly one 721 item is being transferred.
                  if (item.amount != 1) {
                      revert InvalidERC721TransferAmount();
                  }
                  // Transfer ERC721 token.
                  _performERC721Transfer(
                      item.token,
                      item.from,
                      item.to,
                      item.identifier
                  );
              } else if (item.itemType == ConduitItemType.ERC1155) {
                  // Transfer ERC1155 token.
                  _performERC1155Transfer(
                      item.token,
                      item.from,
                      item.to,
                      item.identifier,
                      item.amount
                  );
              } else {
                  // Throw with an error.
                  revert InvalidItemType();
              }
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import { ConduitItemType } from "./ConduitEnums.sol";
      struct ConduitTransfer {
          ConduitItemType itemType;
          address token;
          address from;
          address to;
          uint256 identifier;
          uint256 amount;
      }
      struct ConduitBatch1155Transfer {
          address token;
          address from;
          address to;
          uint256[] ids;
          uint256[] amounts;
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import {
          TransferHelperItem,
          TransferHelperItemsWithRecipient
      } from "../helpers/TransferHelperStructs.sol";
      interface TransferHelperInterface {
          /**
           * @notice Transfer multiple items to a single recipient.
           *
           * @param items The items to transfer.
           * @param conduitKey  The key of the conduit performing the bulk transfer.
           */
          function bulkTransfer(
              TransferHelperItemsWithRecipient[] calldata items,
              bytes32 conduitKey
          ) external returns (bytes4);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      /**
       * @title TransferHelperErrors
       */
      interface TransferHelperErrors {
          /**
           * @dev Revert with an error when attempting to execute transfers with a
           *      NATIVE itemType.
           */
          error InvalidItemType();
          /**
           * @dev Revert with an error when an ERC721 transfer with amount other than
           *      one is attempted.
           */
          error InvalidERC721TransferAmount();
          /**
           * @dev Revert with an error when attempting to execute an ERC721 transfer
           *      to an invalid recipient.
           */
          error InvalidERC721Recipient(address recipient);
          /**
           * @dev Revert with an error when a call to a ERC721 receiver reverts with
           *      bytes data.
           */
          error ERC721ReceiverErrorRevertBytes(
              bytes reason,
              address receiver,
              address sender,
              uint256 identifier
          );
          /**
           * @dev Revert with an error when a call to a ERC721 receiver reverts with
           *      string reason.
           */
          error ERC721ReceiverErrorRevertString(
              string reason,
              address receiver,
              address sender,
              uint256 identifier
          );
          /**
           * @dev Revert with an error when an ERC20 token has an invalid identifier.
           */
          error InvalidERC20Identifier();
          /**
           * @dev Revert with an error if the recipient is the zero address.
           */
          error RecipientCannotBeZeroAddress();
          /**
           * @dev Revert with an error when attempting to fill an order referencing an
           *      invalid conduit (i.e. one that has not been deployed).
           */
          error InvalidConduit(bytes32 conduitKey, address conduit);
          /**
           * @dev Revert with an error when a call to a conduit reverts with a
           *      reason string.
           */
          error ConduitErrorRevertString(
              string reason,
              bytes32 conduitKey,
              address conduit
          );
          /**
           * @dev Revert with an error when a call to a conduit reverts with bytes
           *      data.
           */
          error ConduitErrorRevertBytes(
              bytes reason,
              bytes32 conduitKey,
              address conduit
          );
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      enum ConduitItemType {
          NATIVE, // unused
          ERC20,
          ERC721,
          ERC1155
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      import "./TokenTransferrerConstants.sol";
      import {
          TokenTransferrerErrors
      } from "../interfaces/TokenTransferrerErrors.sol";
      import { ConduitBatch1155Transfer } from "../conduit/lib/ConduitStructs.sol";
      /**
       * @title TokenTransferrer
       * @author 0age
       * @custom:coauthor d1ll0n
       * @custom:coauthor transmissions11
       * @notice TokenTransferrer is a library for performing optimized ERC20, ERC721,
       *         ERC1155, and batch ERC1155 transfers, used by both Seaport as well as
       *         by conduits deployed by the ConduitController. Use great caution when
       *         considering these functions for use in other codebases, as there are
       *         significant side effects and edge cases that need to be thoroughly
       *         understood and carefully addressed.
       */
      contract TokenTransferrer is TokenTransferrerErrors {
          /**
           * @dev Internal function to transfer ERC20 tokens from a given originator
           *      to a given recipient. Sufficient approvals must be set on the
           *      contract performing the transfer.
           *
           * @param token      The ERC20 token to transfer.
           * @param from       The originator of the transfer.
           * @param to         The recipient of the transfer.
           * @param amount     The amount to transfer.
           */
          function _performERC20Transfer(
              address token,
              address from,
              address to,
              uint256 amount
          ) internal {
              // Utilize assembly to perform an optimized ERC20 token transfer.
              assembly {
                  // The free memory pointer memory slot will be used when populating
                  // call data for the transfer; read the value and restore it later.
                  let memPointer := mload(FreeMemoryPointerSlot)
                  // Write call data into memory, starting with function selector.
                  mstore(ERC20_transferFrom_sig_ptr, ERC20_transferFrom_signature)
                  mstore(ERC20_transferFrom_from_ptr, from)
                  mstore(ERC20_transferFrom_to_ptr, to)
                  mstore(ERC20_transferFrom_amount_ptr, amount)
                  // Make call & copy up to 32 bytes of return data to scratch space.
                  // Scratch space does not need to be cleared ahead of time, as the
                  // subsequent check will ensure that either at least a full word of
                  // return data is received (in which case it will be overwritten) or
                  // that no data is received (in which case scratch space will be
                  // ignored) on a successful call to the given token.
                  let callStatus := call(
                      gas(),
                      token,
                      0,
                      ERC20_transferFrom_sig_ptr,
                      ERC20_transferFrom_length,
                      0,
                      OneWord
                  )
                  // Determine whether transfer was successful using status & result.
                  let success := and(
                      // Set success to whether the call reverted, if not check it
                      // either returned exactly 1 (can't just be non-zero data), or
                      // had no return data.
                      or(
                          and(eq(mload(0), 1), gt(returndatasize(), 31)),
                          iszero(returndatasize())
                      ),
                      callStatus
                  )
                  // Handle cases where either the transfer failed or no data was
                  // returned. Group these, as most transfers will succeed with data.
                  // Equivalent to `or(iszero(success), iszero(returndatasize()))`
                  // but after it's inverted for JUMPI this expression is cheaper.
                  if iszero(and(success, iszero(iszero(returndatasize())))) {
                      // If the token has no code or the transfer failed: Equivalent
                      // to `or(iszero(success), iszero(extcodesize(token)))` but
                      // after it's inverted for JUMPI this expression is cheaper.
                      if iszero(and(iszero(iszero(extcodesize(token))), success)) {
                          // If the transfer failed:
                          if iszero(success) {
                              // If it was due to a revert:
                              if iszero(callStatus) {
                                  // If it returned a message, bubble it up as long as
                                  // sufficient gas remains to do so:
                                  if returndatasize() {
                                      // Ensure that sufficient gas is available to
                                      // copy returndata while expanding memory where
                                      // necessary. Start by computing the word size
                                      // of returndata and allocated memory. Round up
                                      // to the nearest full word.
                                      let returnDataWords := div(
                                          add(returndatasize(), AlmostOneWord),
                                          OneWord
                                      )
                                      // Note: use the free memory pointer in place of
                                      // msize() to work around a Yul warning that
                                      // prevents accessing msize directly when the IR
                                      // pipeline is activated.
                                      let msizeWords := div(memPointer, OneWord)
                                      // Next, compute the cost of the returndatacopy.
                                      let cost := mul(CostPerWord, returnDataWords)
                                      // Then, compute cost of new memory allocation.
                                      if gt(returnDataWords, msizeWords) {
                                          cost := add(
                                              cost,
                                              add(
                                                  mul(
                                                      sub(
                                                          returnDataWords,
                                                          msizeWords
                                                      ),
                                                      CostPerWord
                                                  ),
                                                  div(
                                                      sub(
                                                          mul(
                                                              returnDataWords,
                                                              returnDataWords
                                                          ),
                                                          mul(msizeWords, msizeWords)
                                                      ),
                                                      MemoryExpansionCoefficient
                                                  )
                                              )
                                          )
                                      }
                                      // Finally, add a small constant and compare to
                                      // gas remaining; bubble up the revert data if
                                      // enough gas is still available.
                                      if lt(add(cost, ExtraGasBuffer), gas()) {
                                          // Copy returndata to memory; overwrite
                                          // existing memory.
                                          returndatacopy(0, 0, returndatasize())
                                          // Revert, specifying memory region with
                                          // copied returndata.
                                          revert(0, returndatasize())
                                      }
                                  }
                                  // Otherwise revert with a generic error message.
                                  mstore(
                                      TokenTransferGenericFailure_error_sig_ptr,
                                      TokenTransferGenericFailure_error_signature
                                  )
                                  mstore(
                                      TokenTransferGenericFailure_error_token_ptr,
                                      token
                                  )
                                  mstore(
                                      TokenTransferGenericFailure_error_from_ptr,
                                      from
                                  )
                                  mstore(TokenTransferGenericFailure_error_to_ptr, to)
                                  mstore(TokenTransferGenericFailure_error_id_ptr, 0)
                                  mstore(
                                      TokenTransferGenericFailure_error_amount_ptr,
                                      amount
                                  )
                                  revert(
                                      TokenTransferGenericFailure_error_sig_ptr,
                                      TokenTransferGenericFailure_error_length
                                  )
                              }
                              // Otherwise revert with a message about the token
                              // returning false or non-compliant return values.
                              mstore(
                                  BadReturnValueFromERC20OnTransfer_error_sig_ptr,
                                  BadReturnValueFromERC20OnTransfer_error_signature
                              )
                              mstore(
                                  BadReturnValueFromERC20OnTransfer_error_token_ptr,
                                  token
                              )
                              mstore(
                                  BadReturnValueFromERC20OnTransfer_error_from_ptr,
                                  from
                              )
                              mstore(
                                  BadReturnValueFromERC20OnTransfer_error_to_ptr,
                                  to
                              )
                              mstore(
                                  BadReturnValueFromERC20OnTransfer_error_amount_ptr,
                                  amount
                              )
                              revert(
                                  BadReturnValueFromERC20OnTransfer_error_sig_ptr,
                                  BadReturnValueFromERC20OnTransfer_error_length
                              )
                          }
                          // Otherwise, revert with error about token not having code:
                          mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                          mstore(NoContract_error_token_ptr, token)
                          revert(NoContract_error_sig_ptr, NoContract_error_length)
                      }
                      // Otherwise, the token just returned no data despite the call
                      // having succeeded; no need to optimize for this as it's not
                      // technically ERC20 compliant.
                  }
                  // Restore the original free memory pointer.
                  mstore(FreeMemoryPointerSlot, memPointer)
                  // Restore the zero slot to zero.
                  mstore(ZeroSlot, 0)
              }
          }
          /**
           * @dev Internal function to transfer an ERC721 token from a given
           *      originator to a given recipient. Sufficient approvals must be set on
           *      the contract performing the transfer. Note that this function does
           *      not check whether the receiver can accept the ERC721 token (i.e. it
           *      does not use `safeTransferFrom`).
           *
           * @param token      The ERC721 token to transfer.
           * @param from       The originator of the transfer.
           * @param to         The recipient of the transfer.
           * @param identifier The tokenId to transfer.
           */
          function _performERC721Transfer(
              address token,
              address from,
              address to,
              uint256 identifier
          ) internal {
              // Utilize assembly to perform an optimized ERC721 token transfer.
              assembly {
                  // If the token has no code, revert.
                  if iszero(extcodesize(token)) {
                      mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                      mstore(NoContract_error_token_ptr, token)
                      revert(NoContract_error_sig_ptr, NoContract_error_length)
                  }
                  // The free memory pointer memory slot will be used when populating
                  // call data for the transfer; read the value and restore it later.
                  let memPointer := mload(FreeMemoryPointerSlot)
                  // Write call data to memory starting with function selector.
                  mstore(ERC721_transferFrom_sig_ptr, ERC721_transferFrom_signature)
                  mstore(ERC721_transferFrom_from_ptr, from)
                  mstore(ERC721_transferFrom_to_ptr, to)
                  mstore(ERC721_transferFrom_id_ptr, identifier)
                  // Perform the call, ignoring return data.
                  let success := call(
                      gas(),
                      token,
                      0,
                      ERC721_transferFrom_sig_ptr,
                      ERC721_transferFrom_length,
                      0,
                      0
                  )
                  // If the transfer reverted:
                  if iszero(success) {
                      // If it returned a message, bubble it up as long as sufficient
                      // gas remains to do so:
                      if returndatasize() {
                          // Ensure that sufficient gas is available to copy
                          // returndata while expanding memory where necessary. Start
                          // by computing word size of returndata & allocated memory.
                          // Round up to the nearest full word.
                          let returnDataWords := div(
                              add(returndatasize(), AlmostOneWord),
                              OneWord
                          )
                          // Note: use the free memory pointer in place of msize() to
                          // work around a Yul warning that prevents accessing msize
                          // directly when the IR pipeline is activated.
                          let msizeWords := div(memPointer, OneWord)
                          // Next, compute the cost of the returndatacopy.
                          let cost := mul(CostPerWord, returnDataWords)
                          // Then, compute cost of new memory allocation.
                          if gt(returnDataWords, msizeWords) {
                              cost := add(
                                  cost,
                                  add(
                                      mul(
                                          sub(returnDataWords, msizeWords),
                                          CostPerWord
                                      ),
                                      div(
                                          sub(
                                              mul(returnDataWords, returnDataWords),
                                              mul(msizeWords, msizeWords)
                                          ),
                                          MemoryExpansionCoefficient
                                      )
                                  )
                              )
                          }
                          // Finally, add a small constant and compare to gas
                          // remaining; bubble up the revert data if enough gas is
                          // still available.
                          if lt(add(cost, ExtraGasBuffer), gas()) {
                              // Copy returndata to memory; overwrite existing memory.
                              returndatacopy(0, 0, returndatasize())
                              // Revert, giving memory region with copied returndata.
                              revert(0, returndatasize())
                          }
                      }
                      // Otherwise revert with a generic error message.
                      mstore(
                          TokenTransferGenericFailure_error_sig_ptr,
                          TokenTransferGenericFailure_error_signature
                      )
                      mstore(TokenTransferGenericFailure_error_token_ptr, token)
                      mstore(TokenTransferGenericFailure_error_from_ptr, from)
                      mstore(TokenTransferGenericFailure_error_to_ptr, to)
                      mstore(TokenTransferGenericFailure_error_id_ptr, identifier)
                      mstore(TokenTransferGenericFailure_error_amount_ptr, 1)
                      revert(
                          TokenTransferGenericFailure_error_sig_ptr,
                          TokenTransferGenericFailure_error_length
                      )
                  }
                  // Restore the original free memory pointer.
                  mstore(FreeMemoryPointerSlot, memPointer)
                  // Restore the zero slot to zero.
                  mstore(ZeroSlot, 0)
              }
          }
          /**
           * @dev Internal function to transfer ERC1155 tokens from a given
           *      originator to a given recipient. Sufficient approvals must be set on
           *      the contract performing the transfer and contract recipients must
           *      implement the ERC1155TokenReceiver interface to indicate that they
           *      are willing to accept the transfer.
           *
           * @param token      The ERC1155 token to transfer.
           * @param from       The originator of the transfer.
           * @param to         The recipient of the transfer.
           * @param identifier The id to transfer.
           * @param amount     The amount to transfer.
           */
          function _performERC1155Transfer(
              address token,
              address from,
              address to,
              uint256 identifier,
              uint256 amount
          ) internal {
              // Utilize assembly to perform an optimized ERC1155 token transfer.
              assembly {
                  // If the token has no code, revert.
                  if iszero(extcodesize(token)) {
                      mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                      mstore(NoContract_error_token_ptr, token)
                      revert(NoContract_error_sig_ptr, NoContract_error_length)
                  }
                  // The following memory slots will be used when populating call data
                  // for the transfer; read the values and restore them later.
                  let memPointer := mload(FreeMemoryPointerSlot)
                  let slot0x80 := mload(Slot0x80)
                  let slot0xA0 := mload(Slot0xA0)
                  let slot0xC0 := mload(Slot0xC0)
                  // Write call data into memory, beginning with function selector.
                  mstore(
                      ERC1155_safeTransferFrom_sig_ptr,
                      ERC1155_safeTransferFrom_signature
                  )
                  mstore(ERC1155_safeTransferFrom_from_ptr, from)
                  mstore(ERC1155_safeTransferFrom_to_ptr, to)
                  mstore(ERC1155_safeTransferFrom_id_ptr, identifier)
                  mstore(ERC1155_safeTransferFrom_amount_ptr, amount)
                  mstore(
                      ERC1155_safeTransferFrom_data_offset_ptr,
                      ERC1155_safeTransferFrom_data_length_offset
                  )
                  mstore(ERC1155_safeTransferFrom_data_length_ptr, 0)
                  // Perform the call, ignoring return data.
                  let success := call(
                      gas(),
                      token,
                      0,
                      ERC1155_safeTransferFrom_sig_ptr,
                      ERC1155_safeTransferFrom_length,
                      0,
                      0
                  )
                  // If the transfer reverted:
                  if iszero(success) {
                      // If it returned a message, bubble it up as long as sufficient
                      // gas remains to do so:
                      if returndatasize() {
                          // Ensure that sufficient gas is available to copy
                          // returndata while expanding memory where necessary. Start
                          // by computing word size of returndata & allocated memory.
                          // Round up to the nearest full word.
                          let returnDataWords := div(
                              add(returndatasize(), AlmostOneWord),
                              OneWord
                          )
                          // Note: use the free memory pointer in place of msize() to
                          // work around a Yul warning that prevents accessing msize
                          // directly when the IR pipeline is activated.
                          let msizeWords := div(memPointer, OneWord)
                          // Next, compute the cost of the returndatacopy.
                          let cost := mul(CostPerWord, returnDataWords)
                          // Then, compute cost of new memory allocation.
                          if gt(returnDataWords, msizeWords) {
                              cost := add(
                                  cost,
                                  add(
                                      mul(
                                          sub(returnDataWords, msizeWords),
                                          CostPerWord
                                      ),
                                      div(
                                          sub(
                                              mul(returnDataWords, returnDataWords),
                                              mul(msizeWords, msizeWords)
                                          ),
                                          MemoryExpansionCoefficient
                                      )
                                  )
                              )
                          }
                          // Finally, add a small constant and compare to gas
                          // remaining; bubble up the revert data if enough gas is
                          // still available.
                          if lt(add(cost, ExtraGasBuffer), gas()) {
                              // Copy returndata to memory; overwrite existing memory.
                              returndatacopy(0, 0, returndatasize())
                              // Revert, giving memory region with copied returndata.
                              revert(0, returndatasize())
                          }
                      }
                      // Otherwise revert with a generic error message.
                      mstore(
                          TokenTransferGenericFailure_error_sig_ptr,
                          TokenTransferGenericFailure_error_signature
                      )
                      mstore(TokenTransferGenericFailure_error_token_ptr, token)
                      mstore(TokenTransferGenericFailure_error_from_ptr, from)
                      mstore(TokenTransferGenericFailure_error_to_ptr, to)
                      mstore(TokenTransferGenericFailure_error_id_ptr, identifier)
                      mstore(TokenTransferGenericFailure_error_amount_ptr, amount)
                      revert(
                          TokenTransferGenericFailure_error_sig_ptr,
                          TokenTransferGenericFailure_error_length
                      )
                  }
                  mstore(Slot0x80, slot0x80) // Restore slot 0x80.
                  mstore(Slot0xA0, slot0xA0) // Restore slot 0xA0.
                  mstore(Slot0xC0, slot0xC0) // Restore slot 0xC0.
                  // Restore the original free memory pointer.
                  mstore(FreeMemoryPointerSlot, memPointer)
                  // Restore the zero slot to zero.
                  mstore(ZeroSlot, 0)
              }
          }
          /**
           * @dev Internal function to transfer ERC1155 tokens from a given
           *      originator to a given recipient. Sufficient approvals must be set on
           *      the contract performing the transfer and contract recipients must
           *      implement the ERC1155TokenReceiver interface to indicate that they
           *      are willing to accept the transfer. NOTE: this function is not
           *      memory-safe; it will overwrite existing memory, restore the free
           *      memory pointer to the default value, and overwrite the zero slot.
           *      This function should only be called once memory is no longer
           *      required and when uninitialized arrays are not utilized, and memory
           *      should be considered fully corrupted (aside from the existence of a
           *      default-value free memory pointer) after calling this function.
           *
           * @param batchTransfers The group of 1155 batch transfers to perform.
           */
          function _performERC1155BatchTransfers(
              ConduitBatch1155Transfer[] calldata batchTransfers
          ) internal {
              // Utilize assembly to perform optimized batch 1155 transfers.
              assembly {
                  let len := batchTransfers.length
                  // Pointer to first head in the array, which is offset to the struct
                  // at each index. This gets incremented after each loop to avoid
                  // multiplying by 32 to get the offset for each element.
                  let nextElementHeadPtr := batchTransfers.offset
                  // Pointer to beginning of the head of the array. This is the
                  // reference position each offset references. It's held static to
                  // let each loop calculate the data position for an element.
                  let arrayHeadPtr := nextElementHeadPtr
                  // Write the function selector, which will be reused for each call:
                  // safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)
                  mstore(
                      ConduitBatch1155Transfer_from_offset,
                      ERC1155_safeBatchTransferFrom_signature
                  )
                  // Iterate over each batch transfer.
                  for {
                      let i := 0
                  } lt(i, len) {
                      i := add(i, 1)
                  } {
                      // Read the offset to the beginning of the element and add
                      // it to pointer to the beginning of the array head to get
                      // the absolute position of the element in calldata.
                      let elementPtr := add(
                          arrayHeadPtr,
                          calldataload(nextElementHeadPtr)
                      )
                      // Retrieve the token from calldata.
                      let token := calldataload(elementPtr)
                      // If the token has no code, revert.
                      if iszero(extcodesize(token)) {
                          mstore(NoContract_error_sig_ptr, NoContract_error_signature)
                          mstore(NoContract_error_token_ptr, token)
                          revert(NoContract_error_sig_ptr, NoContract_error_length)
                      }
                      // Get the total number of supplied ids.
                      let idsLength := calldataload(
                          add(elementPtr, ConduitBatch1155Transfer_ids_length_offset)
                      )
                      // Determine the expected offset for the amounts array.
                      let expectedAmountsOffset := add(
                          ConduitBatch1155Transfer_amounts_length_baseOffset,
                          mul(idsLength, OneWord)
                      )
                      // Validate struct encoding.
                      let invalidEncoding := iszero(
                          and(
                              // ids.length == amounts.length
                              eq(
                                  idsLength,
                                  calldataload(add(elementPtr, expectedAmountsOffset))
                              ),
                              and(
                                  // ids_offset == 0xa0
                                  eq(
                                      calldataload(
                                          add(
                                              elementPtr,
                                              ConduitBatch1155Transfer_ids_head_offset
                                          )
                                      ),
                                      ConduitBatch1155Transfer_ids_length_offset
                                  ),
                                  // amounts_offset == 0xc0 + ids.length*32
                                  eq(
                                      calldataload(
                                          add(
                                              elementPtr,
                                              ConduitBatchTransfer_amounts_head_offset
                                          )
                                      ),
                                      expectedAmountsOffset
                                  )
                              )
                          )
                      )
                      // Revert with an error if the encoding is not valid.
                      if invalidEncoding {
                          mstore(
                              Invalid1155BatchTransferEncoding_ptr,
                              Invalid1155BatchTransferEncoding_selector
                          )
                          revert(
                              Invalid1155BatchTransferEncoding_ptr,
                              Invalid1155BatchTransferEncoding_length
                          )
                      }
                      // Update the offset position for the next loop
                      nextElementHeadPtr := add(nextElementHeadPtr, OneWord)
                      // Copy the first section of calldata (before dynamic values).
                      calldatacopy(
                          BatchTransfer1155Params_ptr,
                          add(elementPtr, ConduitBatch1155Transfer_from_offset),
                          ConduitBatch1155Transfer_usable_head_size
                      )
                      // Determine size of calldata required for ids and amounts. Note
                      // that the size includes both lengths as well as the data.
                      let idsAndAmountsSize := add(TwoWords, mul(idsLength, TwoWords))
                      // Update the offset for the data array in memory.
                      mstore(
                          BatchTransfer1155Params_data_head_ptr,
                          add(
                              BatchTransfer1155Params_ids_length_offset,
                              idsAndAmountsSize
                          )
                      )
                      // Set the length of the data array in memory to zero.
                      mstore(
                          add(
                              BatchTransfer1155Params_data_length_basePtr,
                              idsAndAmountsSize
                          ),
                          0
                      )
                      // Determine the total calldata size for the call to transfer.
                      let transferDataSize := add(
                          BatchTransfer1155Params_calldata_baseSize,
                          idsAndAmountsSize
                      )
                      // Copy second section of calldata (including dynamic values).
                      calldatacopy(
                          BatchTransfer1155Params_ids_length_ptr,
                          add(elementPtr, ConduitBatch1155Transfer_ids_length_offset),
                          idsAndAmountsSize
                      )
                      // Perform the call to transfer 1155 tokens.
                      let success := call(
                          gas(),
                          token,
                          0,
                          ConduitBatch1155Transfer_from_offset, // Data portion start.
                          transferDataSize, // Location of the length of callData.
                          0,
                          0
                      )
                      // If the transfer reverted:
                      if iszero(success) {
                          // If it returned a message, bubble it up as long as
                          // sufficient gas remains to do so:
                          if returndatasize() {
                              // Ensure that sufficient gas is available to copy
                              // returndata while expanding memory where necessary.
                              // Start by computing word size of returndata and
                              // allocated memory. Round up to the nearest full word.
                              let returnDataWords := div(
                                  add(returndatasize(), AlmostOneWord),
                                  OneWord
                              )
                              // Note: use transferDataSize in place of msize() to
                              // work around a Yul warning that prevents accessing
                              // msize directly when the IR pipeline is activated.
                              // The free memory pointer is not used here because
                              // this function does almost all memory management
                              // manually and does not update it, and transferDataSize
                              // should be the largest memory value used (unless a
                              // previous batch was larger).
                              let msizeWords := div(transferDataSize, OneWord)
                              // Next, compute the cost of the returndatacopy.
                              let cost := mul(CostPerWord, returnDataWords)
                              // Then, compute cost of new memory allocation.
                              if gt(returnDataWords, msizeWords) {
                                  cost := add(
                                      cost,
                                      add(
                                          mul(
                                              sub(returnDataWords, msizeWords),
                                              CostPerWord
                                          ),
                                          div(
                                              sub(
                                                  mul(
                                                      returnDataWords,
                                                      returnDataWords
                                                  ),
                                                  mul(msizeWords, msizeWords)
                                              ),
                                              MemoryExpansionCoefficient
                                          )
                                      )
                                  )
                              }
                              // Finally, add a small constant and compare to gas
                              // remaining; bubble up the revert data if enough gas is
                              // still available.
                              if lt(add(cost, ExtraGasBuffer), gas()) {
                                  // Copy returndata to memory; overwrite existing.
                                  returndatacopy(0, 0, returndatasize())
                                  // Revert with memory region containing returndata.
                                  revert(0, returndatasize())
                              }
                          }
                          // Set the error signature.
                          mstore(
                              0,
                              ERC1155BatchTransferGenericFailure_error_signature
                          )
                          // Write the token.
                          mstore(ERC1155BatchTransferGenericFailure_token_ptr, token)
                          // Increase the offset to ids by 32.
                          mstore(
                              BatchTransfer1155Params_ids_head_ptr,
                              ERC1155BatchTransferGenericFailure_ids_offset
                          )
                          // Increase the offset to amounts by 32.
                          mstore(
                              BatchTransfer1155Params_amounts_head_ptr,
                              add(
                                  OneWord,
                                  mload(BatchTransfer1155Params_amounts_head_ptr)
                              )
                          )
                          // Return modified region. The total size stays the same as
                          // `token` uses the same number of bytes as `data.length`.
                          revert(0, transferDataSize)
                      }
                  }
                  // Reset the free memory pointer to the default value; memory must
                  // be assumed to be dirtied and not reused from this point forward.
                  // Also note that the zero slot is not reset to zero, meaning empty
                  // arrays cannot be safely created or utilized until it is restored.
                  mstore(FreeMemoryPointerSlot, DefaultFreeMemoryPointer)
              }
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      // error ChannelClosed(address channel)
      uint256 constant ChannelClosed_error_signature = (
          0x93daadf200000000000000000000000000000000000000000000000000000000
      );
      uint256 constant ChannelClosed_error_ptr = 0x00;
      uint256 constant ChannelClosed_channel_ptr = 0x4;
      uint256 constant ChannelClosed_error_length = 0x24;
      // For the mapping:
      // mapping(address => bool) channels
      // The position in storage for a particular account is:
      // keccak256(abi.encode(account, channels.slot))
      uint256 constant ChannelKey_channel_ptr = 0x00;
      uint256 constant ChannelKey_slot_ptr = 0x20;
      uint256 constant ChannelKey_length = 0x40;
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      /*
       * -------------------------- Disambiguation & Other Notes ---------------------
       *    - The term "head" is used as it is in the documentation for ABI encoding,
       *      but only in reference to dynamic types, i.e. it always refers to the
       *      offset or pointer to the body of a dynamic type. In calldata, the head
       *      is always an offset (relative to the parent object), while in memory,
       *      the head is always the pointer to the body. More information found here:
       *      https://docs.soliditylang.org/en/v0.8.14/abi-spec.html#argument-encoding
       *        - Note that the length of an array is separate from and precedes the
       *          head of the array.
       *
       *    - The term "body" is used in place of the term "head" used in the ABI
       *      documentation. It refers to the start of the data for a dynamic type,
       *      e.g. the first word of a struct or the first word of the first element
       *      in an array.
       *
       *    - The term "pointer" is used to describe the absolute position of a value
       *      and never an offset relative to another value.
       *        - The suffix "_ptr" refers to a memory pointer.
       *        - The suffix "_cdPtr" refers to a calldata pointer.
       *
       *    - The term "offset" is used to describe the position of a value relative
       *      to some parent value. For example, OrderParameters_conduit_offset is the
       *      offset to the "conduit" value in the OrderParameters struct relative to
       *      the start of the body.
       *        - Note: Offsets are used to derive pointers.
       *
       *    - Some structs have pointers defined for all of their fields in this file.
       *      Lines which are commented out are fields that are not used in the
       *      codebase but have been left in for readability.
       */
      uint256 constant AlmostOneWord = 0x1f;
      uint256 constant OneWord = 0x20;
      uint256 constant TwoWords = 0x40;
      uint256 constant ThreeWords = 0x60;
      uint256 constant FreeMemoryPointerSlot = 0x40;
      uint256 constant ZeroSlot = 0x60;
      uint256 constant DefaultFreeMemoryPointer = 0x80;
      uint256 constant Slot0x80 = 0x80;
      uint256 constant Slot0xA0 = 0xa0;
      uint256 constant Slot0xC0 = 0xc0;
      // abi.encodeWithSignature("transferFrom(address,address,uint256)")
      uint256 constant ERC20_transferFrom_signature = (
          0x23b872dd00000000000000000000000000000000000000000000000000000000
      );
      uint256 constant ERC20_transferFrom_sig_ptr = 0x0;
      uint256 constant ERC20_transferFrom_from_ptr = 0x04;
      uint256 constant ERC20_transferFrom_to_ptr = 0x24;
      uint256 constant ERC20_transferFrom_amount_ptr = 0x44;
      uint256 constant ERC20_transferFrom_length = 0x64; // 4 + 32 * 3 == 100
      // abi.encodeWithSignature(
      //     "safeTransferFrom(address,address,uint256,uint256,bytes)"
      // )
      uint256 constant ERC1155_safeTransferFrom_signature = (
          0xf242432a00000000000000000000000000000000000000000000000000000000
      );
      uint256 constant ERC1155_safeTransferFrom_sig_ptr = 0x0;
      uint256 constant ERC1155_safeTransferFrom_from_ptr = 0x04;
      uint256 constant ERC1155_safeTransferFrom_to_ptr = 0x24;
      uint256 constant ERC1155_safeTransferFrom_id_ptr = 0x44;
      uint256 constant ERC1155_safeTransferFrom_amount_ptr = 0x64;
      uint256 constant ERC1155_safeTransferFrom_data_offset_ptr = 0x84;
      uint256 constant ERC1155_safeTransferFrom_data_length_ptr = 0xa4;
      uint256 constant ERC1155_safeTransferFrom_length = 0xc4; // 4 + 32 * 6 == 196
      uint256 constant ERC1155_safeTransferFrom_data_length_offset = 0xa0;
      // abi.encodeWithSignature(
      //     "safeBatchTransferFrom(address,address,uint256[],uint256[],bytes)"
      // )
      uint256 constant ERC1155_safeBatchTransferFrom_signature = (
          0x2eb2c2d600000000000000000000000000000000000000000000000000000000
      );
      bytes4 constant ERC1155_safeBatchTransferFrom_selector = bytes4(
          bytes32(ERC1155_safeBatchTransferFrom_signature)
      );
      uint256 constant ERC721_transferFrom_signature = ERC20_transferFrom_signature;
      uint256 constant ERC721_transferFrom_sig_ptr = 0x0;
      uint256 constant ERC721_transferFrom_from_ptr = 0x04;
      uint256 constant ERC721_transferFrom_to_ptr = 0x24;
      uint256 constant ERC721_transferFrom_id_ptr = 0x44;
      uint256 constant ERC721_transferFrom_length = 0x64; // 4 + 32 * 3 == 100
      // abi.encodeWithSignature("NoContract(address)")
      uint256 constant NoContract_error_signature = (
          0x5f15d67200000000000000000000000000000000000000000000000000000000
      );
      uint256 constant NoContract_error_sig_ptr = 0x0;
      uint256 constant NoContract_error_token_ptr = 0x4;
      uint256 constant NoContract_error_length = 0x24; // 4 + 32 == 36
      // abi.encodeWithSignature(
      //     "TokenTransferGenericFailure(address,address,address,uint256,uint256)"
      // )
      uint256 constant TokenTransferGenericFailure_error_signature = (
          0xf486bc8700000000000000000000000000000000000000000000000000000000
      );
      uint256 constant TokenTransferGenericFailure_error_sig_ptr = 0x0;
      uint256 constant TokenTransferGenericFailure_error_token_ptr = 0x4;
      uint256 constant TokenTransferGenericFailure_error_from_ptr = 0x24;
      uint256 constant TokenTransferGenericFailure_error_to_ptr = 0x44;
      uint256 constant TokenTransferGenericFailure_error_id_ptr = 0x64;
      uint256 constant TokenTransferGenericFailure_error_amount_ptr = 0x84;
      // 4 + 32 * 5 == 164
      uint256 constant TokenTransferGenericFailure_error_length = 0xa4;
      // abi.encodeWithSignature(
      //     "BadReturnValueFromERC20OnTransfer(address,address,address,uint256)"
      // )
      uint256 constant BadReturnValueFromERC20OnTransfer_error_signature = (
          0x9889192300000000000000000000000000000000000000000000000000000000
      );
      uint256 constant BadReturnValueFromERC20OnTransfer_error_sig_ptr = 0x0;
      uint256 constant BadReturnValueFromERC20OnTransfer_error_token_ptr = 0x4;
      uint256 constant BadReturnValueFromERC20OnTransfer_error_from_ptr = 0x24;
      uint256 constant BadReturnValueFromERC20OnTransfer_error_to_ptr = 0x44;
      uint256 constant BadReturnValueFromERC20OnTransfer_error_amount_ptr = 0x64;
      // 4 + 32 * 4 == 132
      uint256 constant BadReturnValueFromERC20OnTransfer_error_length = 0x84;
      uint256 constant ExtraGasBuffer = 0x20;
      uint256 constant CostPerWord = 3;
      uint256 constant MemoryExpansionCoefficient = 0x200;
      // Values are offset by 32 bytes in order to write the token to the beginning
      // in the event of a revert
      uint256 constant BatchTransfer1155Params_ptr = 0x24;
      uint256 constant BatchTransfer1155Params_ids_head_ptr = 0x64;
      uint256 constant BatchTransfer1155Params_amounts_head_ptr = 0x84;
      uint256 constant BatchTransfer1155Params_data_head_ptr = 0xa4;
      uint256 constant BatchTransfer1155Params_data_length_basePtr = 0xc4;
      uint256 constant BatchTransfer1155Params_calldata_baseSize = 0xc4;
      uint256 constant BatchTransfer1155Params_ids_length_ptr = 0xc4;
      uint256 constant BatchTransfer1155Params_ids_length_offset = 0xa0;
      uint256 constant BatchTransfer1155Params_amounts_length_baseOffset = 0xc0;
      uint256 constant BatchTransfer1155Params_data_length_baseOffset = 0xe0;
      uint256 constant ConduitBatch1155Transfer_usable_head_size = 0x80;
      uint256 constant ConduitBatch1155Transfer_from_offset = 0x20;
      uint256 constant ConduitBatch1155Transfer_ids_head_offset = 0x60;
      uint256 constant ConduitBatch1155Transfer_amounts_head_offset = 0x80;
      uint256 constant ConduitBatch1155Transfer_ids_length_offset = 0xa0;
      uint256 constant ConduitBatch1155Transfer_amounts_length_baseOffset = 0xc0;
      uint256 constant ConduitBatch1155Transfer_calldata_baseSize = 0xc0;
      // Note: abbreviated version of above constant to adhere to line length limit.
      uint256 constant ConduitBatchTransfer_amounts_head_offset = 0x80;
      uint256 constant Invalid1155BatchTransferEncoding_ptr = 0x00;
      uint256 constant Invalid1155BatchTransferEncoding_length = 0x04;
      uint256 constant Invalid1155BatchTransferEncoding_selector = (
          0xeba2084c00000000000000000000000000000000000000000000000000000000
      );
      uint256 constant ERC1155BatchTransferGenericFailure_error_signature = (
          0xafc445e200000000000000000000000000000000000000000000000000000000
      );
      uint256 constant ERC1155BatchTransferGenericFailure_token_ptr = 0x04;
      uint256 constant ERC1155BatchTransferGenericFailure_ids_offset = 0xc0;
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.7;
      /**
       * @title TokenTransferrerErrors
       */
      interface TokenTransferrerErrors {
          /**
           * @dev Revert with an error when an ERC721 transfer with amount other than
           *      one is attempted.
           */
          error InvalidERC721TransferAmount();
          /**
           * @dev Revert with an error when attempting to fulfill an order where an
           *      item has an amount of zero.
           */
          error MissingItemAmount();
          /**
           * @dev Revert with an error when attempting to fulfill an order where an
           *      item has unused parameters. This includes both the token and the
           *      identifier parameters for native transfers as well as the identifier
           *      parameter for ERC20 transfers. Note that the conduit does not
           *      perform this check, leaving it up to the calling channel to enforce
           *      when desired.
           */
          error UnusedItemParameters();
          /**
           * @dev Revert with an error when an ERC20, ERC721, or ERC1155 token
           *      transfer reverts.
           *
           * @param token      The token for which the transfer was attempted.
           * @param from       The source of the attempted transfer.
           * @param to         The recipient of the attempted transfer.
           * @param identifier The identifier for the attempted transfer.
           * @param amount     The amount for the attempted transfer.
           */
          error TokenTransferGenericFailure(
              address token,
              address from,
              address to,
              uint256 identifier,
              uint256 amount
          );
          /**
           * @dev Revert with an error when a batch ERC1155 token transfer reverts.
           *
           * @param token       The token for which the transfer was attempted.
           * @param from        The source of the attempted transfer.
           * @param to          The recipient of the attempted transfer.
           * @param identifiers The identifiers for the attempted transfer.
           * @param amounts     The amounts for the attempted transfer.
           */
          error ERC1155BatchTransferGenericFailure(
              address token,
              address from,
              address to,
              uint256[] identifiers,
              uint256[] amounts
          );
          /**
           * @dev Revert with an error when an ERC20 token transfer returns a falsey
           *      value.
           *
           * @param token      The token for which the ERC20 transfer was attempted.
           * @param from       The source of the attempted ERC20 transfer.
           * @param to         The recipient of the attempted ERC20 transfer.
           * @param amount     The amount for the attempted ERC20 transfer.
           */
          error BadReturnValueFromERC20OnTransfer(
              address token,
              address from,
              address to,
              uint256 amount
          );
          /**
           * @dev Revert with an error when an account being called as an assumed
           *      contract does not have code and returns no data.
           *
           * @param account The account that should contain code.
           */
          error NoContract(address account);
          /**
           * @dev Revert with an error when attempting to execute an 1155 batch
           *      transfer using calldata not produced by default ABI encoding or with
           *      different lengths for ids and amounts arrays.
           */
          error Invalid1155BatchTransferEncoding();
      }
      

      File 2 of 2: DefimonsApartments
      //SPDX-License-Identifier: MIT
      pragma solidity ^0.8.13;
      import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
      import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
      import {MerkleProof} from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
      import {Math} from "@openzeppelin/contracts/utils/math/Math.sol";
      import {ONFT721} from "../Omnichain/token/onft/ONFT721.sol";
      /**
                                                                                                                                                                                                                                                               
                                                                                                                                                                                                                                                                
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       */
      contract DefimonsApartments is ONFT721 {
          //
          // Using Statements
          //
          using MerkleProof for bytes32[];
          using SafeERC20 for IERC20;
          //
          // Constants
          //
          uint16 public constant MAX_MINT = 9500;
          //
          // Errors
          //
          error InvalidSaleInterval(uint256 start, uint256 finish);
          error InvalidWhitelistRoot();
          error SaleNotFound(uint256 saleId);
          error ZeroMintQuantity();
          error NotInSalePhase(
              uint256 saleId,
              uint256 start,
              uint256 finish,
              uint256 current
          );
          error UserNotWhitelistedOrWrongProof(
              uint256 saleId,
              address user,
              bytes32[] proof
          );
          error WrongValueSentForMint(
              uint256 saleId,
              uint256 value,
              uint256 price,
              uint8 quantity
          );
          error MaximumSaleLimitReached(uint256 saleId, address user, uint8 limit);
          error MaximumSupplyReached();
          //
          // Events
          //
          event LogSetURI(string newURI);
          event LogSaleCreated(
              uint256 indexed saleId,
              uint64 start,
              uint64 finish,
              uint8 limit,
              uint64 price,
              bool whitelist,
              bytes32 root
          );
          event LogSaleEdited(
              uint256 indexed saleId,
              uint64 start,
              uint64 finish,
              uint8 limit,
              uint64 price,
              bool whitelist,
              bytes32 root
          );
          event LogSale(uint256 indexed saleId, address indexed to, uint256 quantity);
          //
          // Structs
          //
          /// Defines the parameters for a sale period.
          /// This is created by the contract's Sale Admin.
          /// A sale period has a start time, finish time, mint price, mint limit and a merkle root.
          /// The root parameter indicates the current sale's merkle root (0 for public sales).
          /// The whitelist boolean is 'true' for all whitelist mint periods and 'false' for public mints.
          /// A sale is active when block.timestamp in interval [start, finish].
          /// The price indicates how much a user has to pay for one NFT in this period.
          /// The limit specifies how many NFTs a user can mint during this period.
          struct Sale {
              bytes32 root;
              bool whitelist;
              uint64 start;
              uint64 finish;
              uint64 price;
              uint8 limit;
          }
          //
          // State
          //
          /// Base NFT metadata URI.
          string private _URI;
          /// Id of the next NFT id to mint (sequential id).
          uint256 public nextToMint = 1;
          /// List of sale phases.
          Sale[] private _sales;
          /// Mapping of the quantity of NFTs minted to each address.
          /// Used to track and cap how many tokens an address is allowed to mint per round.
          /// current sale id => user address => number of NFTs minted
          mapping(uint256 => mapping(address => uint256)) private _minted;
          //
          // ERC721
          //
          /// @dev See {IERC721Metadata-tokenURI}.
          function _baseURI() internal view override returns (string memory) {
              return _URI;
          }
          //
          // Constructor
          //
          constructor(
              string memory _name,
              string memory _symbol,
              address _lzEndpoint,
              string memory _initialURI
          ) ONFT721(_name, _symbol, _lzEndpoint) {
              setURI(_initialURI);
          }
          //
          // Owner API
          //
          function setURI(string memory _newURI) public onlyOwner {
              _URI = _newURI;
              emit LogSetURI(_newURI);
          }
          /// @notice Adds a new sale period.
          /// @dev Can only be called by the contract owner.
          /// @param _start The start of the sale.
          /// @param _finish The end of the sale.
          /// @param _limit The maximum number of NFTs an account can mint during this period.
          /// @param _price The price of each NFT during this period.
          /// @param _whitelist Whether the sale is a whitelist sale
          /// @param _root When adding a whitelist sale, this parameter defines the merkle root to be used for verification.
          function addSale(
              uint64 _start,
              uint64 _finish,
              uint8 _limit,
              uint64 _price,
              bool _whitelist,
              bytes32 _root
          ) external onlyOwner {
              _validateSaleParams(_start, _finish, _whitelist, _root);
              Sale memory sale = Sale({
                  start: _start,
                  finish: _finish,
                  limit: _limit,
                  price: _price,
                  whitelist: _whitelist,
                  root: _root
              });
              _sales.push(sale);
              emit LogSaleCreated(
                  _sales.length - 1,
                  _start,
                  _finish,
                  _limit,
                  _price,
                  _whitelist,
                  _root
              );
          }
          /// @notice Edits a Sale Phase
          /// @dev Can only be called by the contract owner.
          /// @param _saleId The unique ID of the sale to be edited
          /// @param _start The new start time we want the sale to have
          /// @param _finish The new end time we want the sale to have
          /// @param _limit The new limit of NFTs we want the sale to have
          /// @param _price The new price we want the NFTs to have
          /// @param _whitelist Whether it is a whitelist sale.
          /// @param _root Defines the root to be used for whitelist verification.
          /// If we want any Sale parameter to stay unchanged, send the same value as a parameter to the function
          function editSale(
              uint256 _saleId,
              uint64 _start,
              uint64 _finish,
              uint8 _limit,
              uint64 _price,
              bool _whitelist,
              bytes32 _root
          ) external onlyOwner {
              _validateSaleParams(_start, _finish, _whitelist, _root);
              if (_saleId >= _sales.length) revert SaleNotFound(_saleId);
              Sale storage sale = _sales[_saleId];
              sale.start = _start;
              sale.finish = _finish;
              sale.limit = _limit;
              sale.price = _price;
              sale.whitelist = _whitelist;
              sale.root = _root;
              emit LogSaleEdited(
                  _saleId,
                  _start,
                  _finish,
                  _limit,
                  _price,
                  _whitelist,
                  _root
              );
          }
          /// @notice Withdraws any ETH sent to this contract.
          /// @dev Only callable by this contract's owner.
          /// @param _to The address to withdraw to.
          /// @param _amount The amount of ETH (in Wei) to withdraw.
          function withdrawEther(address _to, uint256 _amount) external onlyOwner {
              payable(_to).transfer(_amount);
          }
          /// Withdraws any ERC20 tokens sent to the contract.
          /// @dev only callable by the owner.
          /// @param _token The ERC20 token to withdraw
          /// @param _to The address to withdraw to.
          /// @param _amount The amount to withdraw
          function withdrawERC20(
              address _token,
              address _to,
              uint256 _amount
          ) external onlyOwner {
              IERC20(_token).safeTransfer(_to, _amount);
          }
          //
          // Public Read API
          //
          function getSale(uint256 _saleId) external view returns (Sale memory) {
              return _sales[_saleId];
          }
          function getSalesCount() external view returns (uint256) {
              return _sales.length;
          }
          function isSaleActive(uint256 _saleId) external view returns (bool) {
              Sale memory sale = _sales[_saleId];
              return block.timestamp >= sale.start && block.timestamp <= sale.finish;
          }
          function getMintedAmount(uint256 _saleId, address _user)
              external
              view
              returns (uint256)
          {
              return _minted[_saleId][_user];
          }
          //
          // Public Write API
          //
          function saleMint(
              uint256 _saleId,
              address _user,
              uint8 _quantity,
              bytes32[] calldata _proof
          ) external payable {
              // check if sale is registered and quantity is grater than zero
              if (_saleId >= _sales.length) revert SaleNotFound(_saleId);
              if (_quantity == 0) revert ZeroMintQuantity();
              Sale memory sale = _sales[_saleId];
              if (block.timestamp < sale.start || block.timestamp > sale.finish)
                  revert NotInSalePhase(
                      _saleId,
                      sale.start,
                      sale.finish,
                      block.timestamp
                  );
              // validate whitelist
              if (sale.whitelist) {
                  bytes32 leaf = keccak256(abi.encodePacked(_user));
                  if (!_verify(sale.root, _proof, leaf))
                      revert UserNotWhitelistedOrWrongProof(_saleId, _user, _proof);
              }
              // validate ETH amount send to contract
              if (msg.value != _quantity * sale.price) {
                  revert WrongValueSentForMint(
                      _saleId,
                      msg.value,
                      sale.price,
                      _quantity
                  );
              }
              // validate individual mint limit
              uint256 availableUser = sale.limit - _minted[_saleId][_user];
              if (availableUser < _quantity) {
                  revert MaximumSaleLimitReached(_saleId, _user, sale.limit);
              }
              // validate total mint limit
              uint256 mintedBefore = nextToMint;
              uint256 availableTotal = 1 + MAX_MINT - mintedBefore;
              if (availableTotal == 0) {
                  revert MaximumSupplyReached();
              }
              // bound the quantity to mint and increase mint count
              uint256 quantityToMint = Math.min(availableTotal, _quantity);
              _minted[_saleId][_user] += quantityToMint;
              nextToMint += quantityToMint;
              // mint NFTs
              for (uint256 i = 0; i < quantityToMint; ) {
                  _mint(_user, mintedBefore + i);
                  unchecked {
                      ++i;
                  }
              }
              // emit sale event
              emit LogSale(_saleId, _user, quantityToMint);
              // refund leftover eth to buyer
              if (quantityToMint < _quantity) {
                  // can fail when minting through a contract
                  payable(msg.sender).transfer(
                      sale.price * (_quantity - quantityToMint)
                  );
              }
          }
          //
          // Internal
          //
          function _validateSaleParams(
              uint64 _start,
              uint64 _finish,
              bool _whitelist,
              bytes32 _root
          ) internal pure {
              if (_start > _finish) revert InvalidSaleInterval(_start, _finish);
              if (_whitelist && _root == bytes32(0)) revert InvalidWhitelistRoot();
          }
          /// @notice Internal merkle proof verification.
          /// @dev Verify that `proof` is valid and `leaf` occurs in the merkle tree with root hash `merkleRoot`.
          /// @param root The Merkle Tree Root to be used for verification
          /// @param proof The merkle proof.
          /// @param leaf The leaf node to find.
          function _verify(
              bytes32 root,
              bytes32[] calldata proof,
              bytes32 leaf
          ) internal pure returns (bool verified) {
              verified = proof.verify(root, leaf);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev Interface of the ERC20 standard as defined in the EIP.
       */
      interface IERC20 {
          /**
           * @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);
          /**
           * @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 `to`.
           *
           * Returns a boolean value indicating whether the operation succeeded.
           *
           * Emits a {Transfer} event.
           */
          function transfer(address to, 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 `from` to `to` 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 from,
              address to,
              uint256 amount
          ) external returns (bool);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)
      pragma solidity ^0.8.0;
      import "../IERC20.sol";
      import "../extensions/draft-IERC20Permit.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 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'
              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) + value;
              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
          }
          function safeDecreaseAllowance(
              IERC20 token,
              address spender,
              uint256 value
          ) internal {
              unchecked {
                  uint256 oldAllowance = token.allowance(address(this), spender);
                  require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
                  uint256 newAllowance = oldAllowance - value;
                  _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
              }
          }
          function safePermit(
              IERC20Permit token,
              address owner,
              address spender,
              uint256 value,
              uint256 deadline,
              uint8 v,
              bytes32 r,
              bytes32 s
          ) internal {
              uint256 nonceBefore = token.nonces(owner);
              token.permit(owner, spender, value, deadline, v, r, s);
              uint256 nonceAfter = token.nonces(owner);
              require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
          }
          /**
           * @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
                  require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (utils/cryptography/MerkleProof.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev These functions deal with verification of Merkle Tree proofs.
       *
       * The proofs can be generated using the JavaScript library
       * https://github.com/miguelmota/merkletreejs[merkletreejs].
       * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
       *
       * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
       *
       * WARNING: You should avoid using leaf values that are 64 bytes long prior to
       * hashing, or use a hash function other than keccak256 for hashing leaves.
       * This is because the concatenation of a sorted pair of internal nodes in
       * the merkle tree could be reinterpreted as a leaf value.
       */
      library MerkleProof {
          /**
           * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
           * defined by `root`. For this, a `proof` must be provided, containing
           * sibling hashes on the branch from the leaf to the root of the tree. Each
           * pair of leaves and each pair of pre-images are assumed to be sorted.
           */
          function verify(
              bytes32[] memory proof,
              bytes32 root,
              bytes32 leaf
          ) internal pure returns (bool) {
              return processProof(proof, leaf) == root;
          }
          /**
           * @dev Calldata version of {verify}
           *
           * _Available since v4.7._
           */
          function verifyCalldata(
              bytes32[] calldata proof,
              bytes32 root,
              bytes32 leaf
          ) internal pure returns (bool) {
              return processProofCalldata(proof, leaf) == root;
          }
          /**
           * @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
           * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
           * hash matches the root of the tree. When processing the proof, the pairs
           * of leafs & pre-images are assumed to be sorted.
           *
           * _Available since v4.4._
           */
          function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
              bytes32 computedHash = leaf;
              for (uint256 i = 0; i < proof.length; i++) {
                  computedHash = _hashPair(computedHash, proof[i]);
              }
              return computedHash;
          }
          /**
           * @dev Calldata version of {processProof}
           *
           * _Available since v4.7._
           */
          function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
              bytes32 computedHash = leaf;
              for (uint256 i = 0; i < proof.length; i++) {
                  computedHash = _hashPair(computedHash, proof[i]);
              }
              return computedHash;
          }
          /**
           * @dev Returns true if the `leaves` can be proved to be a part of a Merkle tree defined by
           * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
           *
           * _Available since v4.7._
           */
          function multiProofVerify(
              bytes32[] memory proof,
              bool[] memory proofFlags,
              bytes32 root,
              bytes32[] memory leaves
          ) internal pure returns (bool) {
              return processMultiProof(proof, proofFlags, leaves) == root;
          }
          /**
           * @dev Calldata version of {multiProofVerify}
           *
           * _Available since v4.7._
           */
          function multiProofVerifyCalldata(
              bytes32[] calldata proof,
              bool[] calldata proofFlags,
              bytes32 root,
              bytes32[] memory leaves
          ) internal pure returns (bool) {
              return processMultiProofCalldata(proof, proofFlags, leaves) == root;
          }
          /**
           * @dev Returns the root of a tree reconstructed from `leaves` and the sibling nodes in `proof`,
           * consuming from one or the other at each step according to the instructions given by
           * `proofFlags`.
           *
           * _Available since v4.7._
           */
          function processMultiProof(
              bytes32[] memory proof,
              bool[] memory proofFlags,
              bytes32[] memory leaves
          ) internal pure returns (bytes32 merkleRoot) {
              // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
              // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
              // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
              // the merkle tree.
              uint256 leavesLen = leaves.length;
              uint256 totalHashes = proofFlags.length;
              // Check proof validity.
              require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");
              // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
              // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
              bytes32[] memory hashes = new bytes32[](totalHashes);
              uint256 leafPos = 0;
              uint256 hashPos = 0;
              uint256 proofPos = 0;
              // At each step, we compute the next hash using two values:
              // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
              //   get the next hash.
              // - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
              //   `proof` array.
              for (uint256 i = 0; i < totalHashes; i++) {
                  bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
                  bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
                  hashes[i] = _hashPair(a, b);
              }
              if (totalHashes > 0) {
                  return hashes[totalHashes - 1];
              } else if (leavesLen > 0) {
                  return leaves[0];
              } else {
                  return proof[0];
              }
          }
          /**
           * @dev Calldata version of {processMultiProof}
           *
           * _Available since v4.7._
           */
          function processMultiProofCalldata(
              bytes32[] calldata proof,
              bool[] calldata proofFlags,
              bytes32[] memory leaves
          ) internal pure returns (bytes32 merkleRoot) {
              // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
              // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
              // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
              // the merkle tree.
              uint256 leavesLen = leaves.length;
              uint256 totalHashes = proofFlags.length;
              // Check proof validity.
              require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");
              // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
              // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
              bytes32[] memory hashes = new bytes32[](totalHashes);
              uint256 leafPos = 0;
              uint256 hashPos = 0;
              uint256 proofPos = 0;
              // At each step, we compute the next hash using two values:
              // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
              //   get the next hash.
              // - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
              //   `proof` array.
              for (uint256 i = 0; i < totalHashes; i++) {
                  bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
                  bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
                  hashes[i] = _hashPair(a, b);
              }
              if (totalHashes > 0) {
                  return hashes[totalHashes - 1];
              } else if (leavesLen > 0) {
                  return leaves[0];
              } else {
                  return proof[0];
              }
          }
          function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
              return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
          }
          function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
              /// @solidity memory-safe-assembly
              assembly {
                  mstore(0x00, a)
                  mstore(0x20, b)
                  value := keccak256(0x00, 0x40)
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (utils/math/Math.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev Standard math utilities missing in the Solidity language.
       */
      library Math {
          enum Rounding {
              Down, // Toward negative infinity
              Up, // Toward infinity
              Zero // Toward zero
          }
          /**
           * @dev Returns the largest of two numbers.
           */
          function max(uint256 a, uint256 b) internal pure returns (uint256) {
              return a >= b ? a : b;
          }
          /**
           * @dev Returns the smallest of two numbers.
           */
          function min(uint256 a, uint256 b) internal pure returns (uint256) {
              return a < b ? a : b;
          }
          /**
           * @dev Returns the average of two numbers. The result is rounded towards
           * zero.
           */
          function average(uint256 a, uint256 b) internal pure returns (uint256) {
              // (a + b) / 2 can overflow.
              return (a & b) + (a ^ b) / 2;
          }
          /**
           * @dev Returns the ceiling of the division of two numbers.
           *
           * This differs from standard division with `/` in that it rounds up instead
           * of rounding down.
           */
          function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
              // (a + b - 1) / b can overflow on addition, so we distribute.
              return a == 0 ? 0 : (a - 1) / b + 1;
          }
          /**
           * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
           * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
           * with further edits by Uniswap Labs also under MIT license.
           */
          function mulDiv(
              uint256 x,
              uint256 y,
              uint256 denominator
          ) internal pure returns (uint256 result) {
              unchecked {
                  // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
                  // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
                  // variables such that product = prod1 * 2^256 + prod0.
                  uint256 prod0; // Least significant 256 bits of the product
                  uint256 prod1; // Most significant 256 bits of the product
                  assembly {
                      let mm := mulmod(x, y, not(0))
                      prod0 := mul(x, y)
                      prod1 := sub(sub(mm, prod0), lt(mm, prod0))
                  }
                  // Handle non-overflow cases, 256 by 256 division.
                  if (prod1 == 0) {
                      return prod0 / denominator;
                  }
                  // Make sure the result is less than 2^256. Also prevents denominator == 0.
                  require(denominator > prod1);
                  ///////////////////////////////////////////////
                  // 512 by 256 division.
                  ///////////////////////////////////////////////
                  // Make division exact by subtracting the remainder from [prod1 prod0].
                  uint256 remainder;
                  assembly {
                      // Compute remainder using mulmod.
                      remainder := mulmod(x, y, denominator)
                      // Subtract 256 bit number from 512 bit number.
                      prod1 := sub(prod1, gt(remainder, prod0))
                      prod0 := sub(prod0, remainder)
                  }
                  // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
                  // See https://cs.stackexchange.com/q/138556/92363.
                  // Does not overflow because the denominator cannot be zero at this stage in the function.
                  uint256 twos = denominator & (~denominator + 1);
                  assembly {
                      // Divide denominator by twos.
                      denominator := div(denominator, twos)
                      // Divide [prod1 prod0] by twos.
                      prod0 := div(prod0, twos)
                      // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                      twos := add(div(sub(0, twos), twos), 1)
                  }
                  // Shift in bits from prod1 into prod0.
                  prod0 |= prod1 * twos;
                  // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
                  // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
                  // four bits. That is, denominator * inv = 1 mod 2^4.
                  uint256 inverse = (3 * denominator) ^ 2;
                  // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
                  // in modular arithmetic, doubling the correct bits in each step.
                  inverse *= 2 - denominator * inverse; // inverse mod 2^8
                  inverse *= 2 - denominator * inverse; // inverse mod 2^16
                  inverse *= 2 - denominator * inverse; // inverse mod 2^32
                  inverse *= 2 - denominator * inverse; // inverse mod 2^64
                  inverse *= 2 - denominator * inverse; // inverse mod 2^128
                  inverse *= 2 - denominator * inverse; // inverse mod 2^256
                  // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
                  // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
                  // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
                  // is no longer required.
                  result = prod0 * inverse;
                  return result;
              }
          }
          /**
           * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
           */
          function mulDiv(
              uint256 x,
              uint256 y,
              uint256 denominator,
              Rounding rounding
          ) internal pure returns (uint256) {
              uint256 result = mulDiv(x, y, denominator);
              if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
                  result += 1;
              }
              return result;
          }
          /**
           * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
           *
           * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
           */
          function sqrt(uint256 a) internal pure returns (uint256) {
              if (a == 0) {
                  return 0;
              }
              // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
              // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
              // `msb(a) <= a < 2*msb(a)`.
              // We also know that `k`, the position of the most significant bit, is such that `msb(a) = 2**k`.
              // This gives `2**k < a <= 2**(k+1)` → `2**(k/2) <= sqrt(a) < 2 ** (k/2+1)`.
              // Using an algorithm similar to the msb computation, we are able to compute `result = 2**(k/2)` which is a
              // good first approximation of `sqrt(a)` with at least 1 correct bit.
              uint256 result = 1;
              uint256 x = a;
              if (x >> 128 > 0) {
                  x >>= 128;
                  result <<= 64;
              }
              if (x >> 64 > 0) {
                  x >>= 64;
                  result <<= 32;
              }
              if (x >> 32 > 0) {
                  x >>= 32;
                  result <<= 16;
              }
              if (x >> 16 > 0) {
                  x >>= 16;
                  result <<= 8;
              }
              if (x >> 8 > 0) {
                  x >>= 8;
                  result <<= 4;
              }
              if (x >> 4 > 0) {
                  x >>= 4;
                  result <<= 2;
              }
              if (x >> 2 > 0) {
                  result <<= 1;
              }
              // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
              // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
              // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
              // into the expected uint128 result.
              unchecked {
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  result = (result + a / result) >> 1;
                  return min(result, a / result);
              }
          }
          /**
           * @notice Calculates sqrt(a), following the selected rounding direction.
           */
          function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
              uint256 result = sqrt(a);
              if (rounding == Rounding.Up && result * result < a) {
                  result += 1;
              }
              return result;
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./IONFT721.sol";
      import "./ONFT721Core.sol";
      import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
      import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
      // NOTE: this ONFT contract has no public minting logic.
      // must implement your own minting logic in child classes
      contract ONFT721 is ONFT721Core, ERC721, IERC721Receiver, IONFT721 {
          constructor(string memory _name, string memory _symbol, address _lzEndpoint) ERC721(_name, _symbol) ONFT721Core(_lzEndpoint) {}
          function supportsInterface(bytes4 interfaceId) public view virtual override(ONFT721Core, ERC721, IERC165) returns (bool) {
              return interfaceId == type(IONFT721).interfaceId || super.supportsInterface(interfaceId);
          }
          function _debitFrom(address _from, uint16, bytes memory, uint _tokenId) internal virtual override {
              require(_isApprovedOrOwner(_msgSender(), _tokenId), "ONFT721: not owner nor approved");
              require(ERC721.ownerOf(_tokenId) == _from, "ONFT721: incorrect owner");
              _burn(_tokenId);
          }
          function _creditTo(uint16, address _toAddress, uint _tokenId) internal virtual override {
              _safeMint(_toAddress, _tokenId);
          }
          function onERC721Received(address _operator, address, uint, bytes memory) public virtual override returns (bytes4) {
              // only allow `this` to tranfser token from others
              if (_operator != address(this)) return bytes4(0);
              return IERC721Receiver.onERC721Received.selector;
          }
          /// @notice Checks if there is a payload waiting to be delivered.
          function hasStoredPayload(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (bool) {
              return lzEndpoint.hasStoredPayload(_srcChainId, _srcAddress);
          }
          /// @notice Retries to send a payload in case an error occurs on receiving chain.
          /// @dev In case an error occurs on receiving chain, the message is stuck in the pipeline until this function is called.
          /// Reason for message failing once contracts are stet up correctly is usually running out of gas.
          /// retry this message with a higher amount of gas.
          /// Info on retriving stored payload: https://layerzero.gitbook.io/docs/guides/error-messages/storedpayload-detection
          /// @param _srcChainId The source chain ID
          /// @param _srcAddress The source address
          /// @param _payload Message payload. THis can be retrieved from etherscan:
          function retryPayload(
              uint16 _srcChainId, 
              bytes calldata _srcAddress, 
              bytes calldata _payload) external payable {
              lzEndpoint.retryPayload(_srcChainId, _srcAddress, _payload);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
       * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
       *
       * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
       * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
       * need to send a transaction, and thus is not required to hold Ether at all.
       */
      interface IERC20Permit {
          /**
           * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
           * given ``owner``'s signed approval.
           *
           * IMPORTANT: The same issues {IERC20-approve} has related to transaction
           * ordering also apply here.
           *
           * Emits an {Approval} event.
           *
           * Requirements:
           *
           * - `spender` cannot be the zero address.
           * - `deadline` must be a timestamp in the future.
           * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
           * over the EIP712-formatted function arguments.
           * - the signature must use ``owner``'s current nonce (see {nonces}).
           *
           * For more information on the signature format, see the
           * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
           * section].
           */
          function permit(
              address owner,
              address spender,
              uint256 value,
              uint256 deadline,
              uint8 v,
              bytes32 r,
              bytes32 s
          ) external;
          /**
           * @dev Returns the current nonce for `owner`. This value must be
           * included whenever a signature is generated for {permit}.
           *
           * Every successful call to {permit} increases ``owner``'s nonce by one. This
           * prevents a signature from being used multiple times.
           */
          function nonces(address owner) external view returns (uint256);
          /**
           * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
           */
          // solhint-disable-next-line func-name-mixedcase
          function DOMAIN_SEPARATOR() external view returns (bytes32);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)
      pragma solidity ^0.8.1;
      /**
       * @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
           * ====
           *
           * [IMPORTANT]
           * ====
           * You shouldn't rely on `isContract` to protect against flash loan attacks!
           *
           * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
           * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
           * constructor.
           * ====
           */
          function isContract(address account) internal view returns (bool) {
              // This method relies on extcodesize/address.code.length, which returns 0
              // for contracts in construction, since the code is only stored at the end
              // of the constructor execution.
              return account.code.length > 0;
          }
          /**
           * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
           * `recipient`, forwarding all available gas and reverting on errors.
           *
           * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
           * of certain opcodes, possibly making contracts go over the 2300 gas limit
           * imposed by `transfer`, making them unable to receive funds via
           * `transfer`. {sendValue} removes this limitation.
           *
           * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
           *
           * IMPORTANT: because control is transferred to `recipient`, care must be
           * taken to not create reentrancy vulnerabilities. Consider using
           * {ReentrancyGuard} or the
           * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
           */
          function sendValue(address payable recipient, uint256 amount) internal {
              require(address(this).balance >= amount, "Address: insufficient balance");
              (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 functionCallWithValue(target, data, 0, "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");
              (bool success, bytes memory returndata) = target.call{value: value}(data);
              return verifyCallResultFromTarget(target, success, returndata, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but performing a static call.
           *
           * _Available since v3.3._
           */
          function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
              return functionStaticCall(target, data, "Address: low-level static call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
           * but performing a static call.
           *
           * _Available since v3.3._
           */
          function functionStaticCall(
              address target,
              bytes memory data,
              string memory errorMessage
          ) internal view returns (bytes memory) {
              (bool success, bytes memory returndata) = target.staticcall(data);
              return verifyCallResultFromTarget(target, success, returndata, errorMessage);
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
           * but performing a delegate call.
           *
           * _Available since v3.4._
           */
          function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
              return functionDelegateCall(target, data, "Address: low-level delegate call failed");
          }
          /**
           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
           * but performing a delegate call.
           *
           * _Available since v3.4._
           */
          function functionDelegateCall(
              address target,
              bytes memory data,
              string memory errorMessage
          ) internal returns (bytes memory) {
              (bool success, bytes memory returndata) = target.delegatecall(data);
              return verifyCallResultFromTarget(target, success, returndata, errorMessage);
          }
          /**
           * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
           * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
           *
           * _Available since v4.8._
           */
          function verifyCallResultFromTarget(
              address target,
              bool success,
              bytes memory returndata,
              string memory errorMessage
          ) internal view returns (bytes memory) {
              if (success) {
                  if (returndata.length == 0) {
                      // only check isContract if the call was successful and the return data is empty
                      // otherwise we already know that it was a contract
                      require(isContract(target), "Address: call to non-contract");
                  }
                  return returndata;
              } else {
                  _revert(returndata, errorMessage);
              }
          }
          /**
           * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
           * revert reason or using the provided one.
           *
           * _Available since v4.3._
           */
          function verifyCallResult(
              bool success,
              bytes memory returndata,
              string memory errorMessage
          ) internal pure returns (bytes memory) {
              if (success) {
                  return returndata;
              } else {
                  _revert(returndata, errorMessage);
              }
          }
          function _revert(bytes memory returndata, string memory errorMessage) private pure {
              // 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
                  /// @solidity memory-safe-assembly
                  assembly {
                      let returndata_size := mload(returndata)
                      revert(add(32, returndata), returndata_size)
                  }
              } else {
                  revert(errorMessage);
              }
          }
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./IONFT721Core.sol";
      import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
      /**
       * @dev Interface of the ONFT standard
       */
      interface IONFT721 is IONFT721Core, IERC721 {
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./IONFT721Core.sol";
      import "../../lzApp/NonblockingLzApp.sol";
      import "@openzeppelin/contracts/utils/introspection/ERC165.sol";
      abstract contract ONFT721Core is NonblockingLzApp, ERC165, IONFT721Core {
          constructor(address _lzEndpoint) NonblockingLzApp(_lzEndpoint) {}
          function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
              return interfaceId == type(IONFT721Core).interfaceId || super.supportsInterface(interfaceId);
          }
          function estimateSendFee(uint16 _dstChainId, bytes memory _toAddress, uint _tokenId, bool _useZro, bytes memory _adapterParams) public view virtual override returns (uint nativeFee, uint zroFee) {
              // mock the payload for send()
              bytes memory payload = abi.encode(_toAddress, _tokenId);
              return lzEndpoint.estimateFees(_dstChainId, address(this), payload, _useZro, _adapterParams);
          }
          function send(uint16 _dstChainId, bytes memory _toAddress, uint _tokenId, address payable _refundAddress, address _zroPaymentAddress, bytes memory _adapterParams) public payable virtual override {
              _send(msg.sender, _dstChainId, _toAddress, _tokenId, _refundAddress, _zroPaymentAddress, _adapterParams);
          }
          function _send(address _from, uint16 _dstChainId, bytes memory _toAddress, uint _tokenId, address payable _refundAddress, address _zroPaymentAddress, bytes memory _adapterParams) internal virtual {
              _debitFrom(_from, _dstChainId, _toAddress, _tokenId);
              bytes memory payload = abi.encode(_toAddress, _tokenId);
              _lzSend(_dstChainId, payload, _refundAddress, _zroPaymentAddress, _adapterParams);
              uint64 nonce = lzEndpoint.getOutboundNonce(_dstChainId, address(this));
              emit SendToChain(_from, _dstChainId, _toAddress, _tokenId, nonce);
          }
          function _nonblockingLzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) internal virtual override {
              // decode and load the toAddress
              (bytes memory toAddressBytes, uint tokenId) = abi.decode(_payload, (bytes, uint));
              address toAddress;
              assembly {
                  toAddress := mload(add(toAddressBytes, 20))
              }
              _creditTo(_srcChainId, toAddress, tokenId);
              emit ReceiveFromChain(_srcChainId, _srcAddress, toAddress, tokenId, _nonce);
          }
          function _debitFrom(address _from, uint16 _dstChainId, bytes memory _toAddress, uint _tokenId) internal virtual;
          function _creditTo(uint16 _srcChainId, address _toAddress, uint _tokenId) internal virtual;
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)
      pragma solidity ^0.8.0;
      /**
       * @title ERC721 token receiver interface
       * @dev Interface for any contract that wants to support safeTransfers
       * from ERC721 asset contracts.
       */
      interface IERC721Receiver {
          /**
           * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
           * by `operator` from `from`, this function is called.
           *
           * It must return its Solidity selector to confirm the token transfer.
           * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
           *
           * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
           */
          function onERC721Received(
              address operator,
              address from,
              uint256 tokenId,
              bytes calldata data
          ) external returns (bytes4);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/ERC721.sol)
      pragma solidity ^0.8.0;
      import "./IERC721.sol";
      import "./IERC721Receiver.sol";
      import "./extensions/IERC721Metadata.sol";
      import "../../utils/Address.sol";
      import "../../utils/Context.sol";
      import "../../utils/Strings.sol";
      import "../../utils/introspection/ERC165.sol";
      /**
       * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
       * the Metadata extension, but not including the Enumerable extension, which is available separately as
       * {ERC721Enumerable}.
       */
      contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
          using Address for address;
          using Strings for uint256;
          // Token name
          string private _name;
          // Token symbol
          string private _symbol;
          // Mapping from token ID to owner address
          mapping(uint256 => address) private _owners;
          // Mapping owner address to token count
          mapping(address => uint256) private _balances;
          // Mapping from token ID to approved address
          mapping(uint256 => address) private _tokenApprovals;
          // Mapping from owner to operator approvals
          mapping(address => mapping(address => bool)) private _operatorApprovals;
          /**
           * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
           */
          constructor(string memory name_, string memory symbol_) {
              _name = name_;
              _symbol = symbol_;
          }
          /**
           * @dev See {IERC165-supportsInterface}.
           */
          function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
              return
                  interfaceId == type(IERC721).interfaceId ||
                  interfaceId == type(IERC721Metadata).interfaceId ||
                  super.supportsInterface(interfaceId);
          }
          /**
           * @dev See {IERC721-balanceOf}.
           */
          function balanceOf(address owner) public view virtual override returns (uint256) {
              require(owner != address(0), "ERC721: address zero is not a valid owner");
              return _balances[owner];
          }
          /**
           * @dev See {IERC721-ownerOf}.
           */
          function ownerOf(uint256 tokenId) public view virtual override returns (address) {
              address owner = _owners[tokenId];
              require(owner != address(0), "ERC721: invalid token ID");
              return owner;
          }
          /**
           * @dev See {IERC721Metadata-name}.
           */
          function name() public view virtual override returns (string memory) {
              return _name;
          }
          /**
           * @dev See {IERC721Metadata-symbol}.
           */
          function symbol() public view virtual override returns (string memory) {
              return _symbol;
          }
          /**
           * @dev See {IERC721Metadata-tokenURI}.
           */
          function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
              _requireMinted(tokenId);
              string memory baseURI = _baseURI();
              return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
          }
          /**
           * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
           * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
           * by default, can be overridden in child contracts.
           */
          function _baseURI() internal view virtual returns (string memory) {
              return "";
          }
          /**
           * @dev See {IERC721-approve}.
           */
          function approve(address to, uint256 tokenId) public virtual override {
              address owner = ERC721.ownerOf(tokenId);
              require(to != owner, "ERC721: approval to current owner");
              require(
                  _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
                  "ERC721: approve caller is not token owner or approved for all"
              );
              _approve(to, tokenId);
          }
          /**
           * @dev See {IERC721-getApproved}.
           */
          function getApproved(uint256 tokenId) public view virtual override returns (address) {
              _requireMinted(tokenId);
              return _tokenApprovals[tokenId];
          }
          /**
           * @dev See {IERC721-setApprovalForAll}.
           */
          function setApprovalForAll(address operator, bool approved) public virtual override {
              _setApprovalForAll(_msgSender(), operator, approved);
          }
          /**
           * @dev See {IERC721-isApprovedForAll}.
           */
          function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
              return _operatorApprovals[owner][operator];
          }
          /**
           * @dev See {IERC721-transferFrom}.
           */
          function transferFrom(
              address from,
              address to,
              uint256 tokenId
          ) public virtual override {
              //solhint-disable-next-line max-line-length
              require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
              _transfer(from, to, tokenId);
          }
          /**
           * @dev See {IERC721-safeTransferFrom}.
           */
          function safeTransferFrom(
              address from,
              address to,
              uint256 tokenId
          ) public virtual override {
              safeTransferFrom(from, to, tokenId, "");
          }
          /**
           * @dev See {IERC721-safeTransferFrom}.
           */
          function safeTransferFrom(
              address from,
              address to,
              uint256 tokenId,
              bytes memory data
          ) public virtual override {
              require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner or approved");
              _safeTransfer(from, to, tokenId, data);
          }
          /**
           * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
           * are aware of the ERC721 protocol to prevent tokens from being forever locked.
           *
           * `data` is additional data, it has no specified format and it is sent in call to `to`.
           *
           * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
           * implement alternative mechanisms to perform token transfer, such as signature-based.
           *
           * Requirements:
           *
           * - `from` cannot be the zero address.
           * - `to` cannot be the zero address.
           * - `tokenId` token must exist and be owned by `from`.
           * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
           *
           * Emits a {Transfer} event.
           */
          function _safeTransfer(
              address from,
              address to,
              uint256 tokenId,
              bytes memory data
          ) internal virtual {
              _transfer(from, to, tokenId);
              require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
          }
          /**
           * @dev Returns whether `tokenId` exists.
           *
           * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
           *
           * Tokens start existing when they are minted (`_mint`),
           * and stop existing when they are burned (`_burn`).
           */
          function _exists(uint256 tokenId) internal view virtual returns (bool) {
              return _owners[tokenId] != address(0);
          }
          /**
           * @dev Returns whether `spender` is allowed to manage `tokenId`.
           *
           * Requirements:
           *
           * - `tokenId` must exist.
           */
          function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
              address owner = ERC721.ownerOf(tokenId);
              return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
          }
          /**
           * @dev Safely mints `tokenId` and transfers it to `to`.
           *
           * Requirements:
           *
           * - `tokenId` must not exist.
           * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
           *
           * Emits a {Transfer} event.
           */
          function _safeMint(address to, uint256 tokenId) internal virtual {
              _safeMint(to, tokenId, "");
          }
          /**
           * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
           * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
           */
          function _safeMint(
              address to,
              uint256 tokenId,
              bytes memory data
          ) internal virtual {
              _mint(to, tokenId);
              require(
                  _checkOnERC721Received(address(0), to, tokenId, data),
                  "ERC721: transfer to non ERC721Receiver implementer"
              );
          }
          /**
           * @dev Mints `tokenId` and transfers it to `to`.
           *
           * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
           *
           * Requirements:
           *
           * - `tokenId` must not exist.
           * - `to` cannot be the zero address.
           *
           * Emits a {Transfer} event.
           */
          function _mint(address to, uint256 tokenId) internal virtual {
              require(to != address(0), "ERC721: mint to the zero address");
              require(!_exists(tokenId), "ERC721: token already minted");
              _beforeTokenTransfer(address(0), to, tokenId);
              _balances[to] += 1;
              _owners[tokenId] = to;
              emit Transfer(address(0), to, tokenId);
              _afterTokenTransfer(address(0), to, tokenId);
          }
          /**
           * @dev Destroys `tokenId`.
           * The approval is cleared when the token is burned.
           * This is an internal function that does not check if the sender is authorized to operate on the token.
           *
           * Requirements:
           *
           * - `tokenId` must exist.
           *
           * Emits a {Transfer} event.
           */
          function _burn(uint256 tokenId) internal virtual {
              address owner = ERC721.ownerOf(tokenId);
              _beforeTokenTransfer(owner, address(0), tokenId);
              // Clear approvals
              delete _tokenApprovals[tokenId];
              _balances[owner] -= 1;
              delete _owners[tokenId];
              emit Transfer(owner, address(0), tokenId);
              _afterTokenTransfer(owner, address(0), tokenId);
          }
          /**
           * @dev Transfers `tokenId` from `from` to `to`.
           *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
           *
           * Requirements:
           *
           * - `to` cannot be the zero address.
           * - `tokenId` token must be owned by `from`.
           *
           * Emits a {Transfer} event.
           */
          function _transfer(
              address from,
              address to,
              uint256 tokenId
          ) internal virtual {
              require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
              require(to != address(0), "ERC721: transfer to the zero address");
              _beforeTokenTransfer(from, to, tokenId);
              // Clear approvals from the previous owner
              delete _tokenApprovals[tokenId];
              _balances[from] -= 1;
              _balances[to] += 1;
              _owners[tokenId] = to;
              emit Transfer(from, to, tokenId);
              _afterTokenTransfer(from, to, tokenId);
          }
          /**
           * @dev Approve `to` to operate on `tokenId`
           *
           * Emits an {Approval} event.
           */
          function _approve(address to, uint256 tokenId) internal virtual {
              _tokenApprovals[tokenId] = to;
              emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
          }
          /**
           * @dev Approve `operator` to operate on all of `owner` tokens
           *
           * Emits an {ApprovalForAll} event.
           */
          function _setApprovalForAll(
              address owner,
              address operator,
              bool approved
          ) internal virtual {
              require(owner != operator, "ERC721: approve to caller");
              _operatorApprovals[owner][operator] = approved;
              emit ApprovalForAll(owner, operator, approved);
          }
          /**
           * @dev Reverts if the `tokenId` has not been minted yet.
           */
          function _requireMinted(uint256 tokenId) internal view virtual {
              require(_exists(tokenId), "ERC721: invalid token ID");
          }
          /**
           * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
           * The call is not executed if the target address is not a contract.
           *
           * @param from address representing the previous owner of the given token ID
           * @param to target address that will receive the tokens
           * @param tokenId uint256 ID of the token to be transferred
           * @param data bytes optional data to send along with the call
           * @return bool whether the call correctly returned the expected magic value
           */
          function _checkOnERC721Received(
              address from,
              address to,
              uint256 tokenId,
              bytes memory data
          ) private returns (bool) {
              if (to.isContract()) {
                  try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                      return retval == IERC721Receiver.onERC721Received.selector;
                  } catch (bytes memory reason) {
                      if (reason.length == 0) {
                          revert("ERC721: transfer to non ERC721Receiver implementer");
                      } else {
                          /// @solidity memory-safe-assembly
                          assembly {
                              revert(add(32, reason), mload(reason))
                          }
                      }
                  }
              } else {
                  return true;
              }
          }
          /**
           * @dev Hook that is called before any token transfer. This includes minting
           * and burning.
           *
           * Calling conditions:
           *
           * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
           * transferred to `to`.
           * - When `from` is zero, `tokenId` will be minted for `to`.
           * - When `to` is zero, ``from``'s `tokenId` 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 tokenId
          ) internal virtual {}
          /**
           * @dev Hook that is called after any transfer of tokens. This includes
           * minting and burning.
           *
           * Calling conditions:
           *
           * - when `from` and `to` are both non-zero.
           * - `from` and `to` are never both zero.
           *
           * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
           */
          function _afterTokenTransfer(
              address from,
              address to,
              uint256 tokenId
          ) internal virtual {}
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "@openzeppelin/contracts/utils/introspection/IERC165.sol";
      /**
       * @dev Interface of the ONFT Core standard
       */
      interface IONFT721Core is IERC165 {
          /**
           * @dev estimate send token `_tokenId` to (`_dstChainId`, `_toAddress`)
           * _dstChainId - L0 defined chain id to send tokens too
           * _toAddress - dynamic bytes array which contains the address to whom you are sending tokens to on the dstChain
           * _tokenId - token Id to transfer
           * _useZro - indicates to use zro to pay L0 fees
           * _adapterParams - flexible bytes array to indicate messaging adapter services in L0
           */
          function estimateSendFee(uint16 _dstChainId, bytes calldata _toAddress, uint _tokenId, bool _useZro, bytes calldata _adapterParams) external view returns (uint nativeFee, uint zroFee);
          /**
           * @dev send token `_tokenId` to (`_dstChainId`, `_toAddress`) from `_from`
           * `_toAddress` can be any size depending on the `dstChainId`.
           * `_zroPaymentAddress` set to address(0x0) if not paying in ZRO (LayerZero Token)
           * `_adapterParams` is a flexible bytes array to indicate messaging adapter services
           */
          function send(uint16 _dstChainId, bytes calldata _toAddress, uint _tokenId, address payable _refundAddress, address _zroPaymentAddress, bytes calldata _adapterParams) external payable;
          /**
           * @dev Emitted when `_tokenId` are moved from the `_sender` to (`_dstChainId`, `_toAddress`)
           * `_nonce` is the outbound nonce from
           */
          event SendToChain(address indexed _sender, uint16 indexed _dstChainId, bytes indexed _toAddress, uint _tokenId, uint64 _nonce);
          /**
           * @dev Emitted when `_tokenId` are sent from `_srcChainId` to the `_toAddress` at this chain. `_nonce` is the inbound nonce.
           */
          event ReceiveFromChain(uint16 indexed _srcChainId, bytes indexed _srcAddress, address indexed _toAddress, uint _tokenId, uint64 _nonce);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)
      pragma solidity ^0.8.0;
      import "../../utils/introspection/IERC165.sol";
      /**
       * @dev Required interface of an ERC721 compliant contract.
       */
      interface IERC721 is IERC165 {
          /**
           * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
           */
          event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
          /**
           * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
           */
          event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
          /**
           * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
           */
          event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
          /**
           * @dev Returns the number of tokens in ``owner``'s account.
           */
          function balanceOf(address owner) external view returns (uint256 balance);
          /**
           * @dev Returns the owner of the `tokenId` token.
           *
           * Requirements:
           *
           * - `tokenId` must exist.
           */
          function ownerOf(uint256 tokenId) external view returns (address owner);
          /**
           * @dev Safely transfers `tokenId` token from `from` to `to`.
           *
           * Requirements:
           *
           * - `from` cannot be the zero address.
           * - `to` cannot be the zero address.
           * - `tokenId` token must exist and be owned by `from`.
           * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
           * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
           *
           * Emits a {Transfer} event.
           */
          function safeTransferFrom(
              address from,
              address to,
              uint256 tokenId,
              bytes calldata data
          ) external;
          /**
           * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
           * are aware of the ERC721 protocol to prevent tokens from being forever locked.
           *
           * Requirements:
           *
           * - `from` cannot be the zero address.
           * - `to` cannot be the zero address.
           * - `tokenId` token must exist and be owned by `from`.
           * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
           * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
           *
           * Emits a {Transfer} event.
           */
          function safeTransferFrom(
              address from,
              address to,
              uint256 tokenId
          ) external;
          /**
           * @dev Transfers `tokenId` token from `from` to `to`.
           *
           * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
           *
           * Requirements:
           *
           * - `from` cannot be the zero address.
           * - `to` cannot be the zero address.
           * - `tokenId` token must be owned by `from`.
           * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
           *
           * Emits a {Transfer} event.
           */
          function transferFrom(
              address from,
              address to,
              uint256 tokenId
          ) external;
          /**
           * @dev Gives permission to `to` to transfer `tokenId` token to another account.
           * The approval is cleared when the token is transferred.
           *
           * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
           *
           * Requirements:
           *
           * - The caller must own the token or be an approved operator.
           * - `tokenId` must exist.
           *
           * Emits an {Approval} event.
           */
          function approve(address to, uint256 tokenId) external;
          /**
           * @dev Approve or remove `operator` as an operator for the caller.
           * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
           *
           * Requirements:
           *
           * - The `operator` cannot be the caller.
           *
           * Emits an {ApprovalForAll} event.
           */
          function setApprovalForAll(address operator, bool _approved) external;
          /**
           * @dev Returns the account approved for `tokenId` token.
           *
           * Requirements:
           *
           * - `tokenId` must exist.
           */
          function getApproved(uint256 tokenId) external view returns (address operator);
          /**
           * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
           *
           * See {setApprovalForAll}
           */
          function isApprovedForAll(address owner, address operator) external view returns (bool);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "./LzApp.sol";
      /*
       * the default LayerZero messaging behaviour is blocking, i.e. any failed message will block the channel
       * this abstract class try-catch all fail messages and store locally for future retry. hence, non-blocking
       * NOTE: if the srcAddress is not configured properly, it will still block the message pathway from (srcChainId, srcAddress)
       */
      abstract contract NonblockingLzApp is LzApp {
          constructor(address _endpoint) LzApp(_endpoint) {}
          mapping(uint16 => mapping(bytes => mapping(uint64 => bytes32))) public failedMessages;
          event MessageFailed(uint16 _srcChainId, bytes _srcAddress, uint64 _nonce, bytes _payload);
          // overriding the virtual function in LzReceiver
          function _blockingLzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) internal virtual override {
              // try-catch all errors/exceptions
              try this.nonblockingLzReceive(_srcChainId, _srcAddress, _nonce, _payload) {
                  // do nothing
              } catch {
                  // error / exception
                  failedMessages[_srcChainId][_srcAddress][_nonce] = keccak256(_payload);
                  emit MessageFailed(_srcChainId, _srcAddress, _nonce, _payload);
              }
          }
          function nonblockingLzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) public virtual {
              // only internal transaction
              require(_msgSender() == address(this), "LzReceiver: caller must be LzApp");
              _nonblockingLzReceive(_srcChainId, _srcAddress, _nonce, _payload);
          }
          //@notice override this function
          function _nonblockingLzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) internal virtual;
          function retryMessage(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes calldata _payload) public payable virtual {
              // assert there is message to retry
              bytes32 payloadHash = failedMessages[_srcChainId][_srcAddress][_nonce];
              require(payloadHash != bytes32(0), "LzReceiver: no stored message");
              require(keccak256(_payload) == payloadHash, "LzReceiver: invalid payload");
              // clear the stored message
              failedMessages[_srcChainId][_srcAddress][_nonce] = bytes32(0);
              // execute the message. revert if it fails again
              _nonblockingLzReceive(_srcChainId, _srcAddress, _nonce, _payload);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
      pragma solidity ^0.8.0;
      import "./IERC165.sol";
      /**
       * @dev Implementation of the {IERC165} interface.
       *
       * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
       * for the additional interface id that will be supported. For example:
       *
       * ```solidity
       * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
       *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
       * }
       * ```
       *
       * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
       */
      abstract contract ERC165 is IERC165 {
          /**
           * @dev See {IERC165-supportsInterface}.
           */
          function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
              return interfaceId == type(IERC165).interfaceId;
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
      pragma solidity ^0.8.0;
      import "../IERC721.sol";
      /**
       * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
       * @dev See https://eips.ethereum.org/EIPS/eip-721
       */
      interface IERC721Metadata is IERC721 {
          /**
           * @dev Returns the token collection name.
           */
          function name() external view returns (string memory);
          /**
           * @dev Returns the token collection symbol.
           */
          function symbol() external view returns (string memory);
          /**
           * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
           */
          function tokenURI(uint256 tokenId) external view returns (string memory);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
      pragma solidity ^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 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;
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev String operations.
       */
      library Strings {
          bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
          uint8 private constant _ADDRESS_LENGTH = 20;
          /**
           * @dev Converts a `uint256` to its ASCII `string` decimal representation.
           */
          function toString(uint256 value) internal pure returns (string memory) {
              // Inspired by OraclizeAPI's implementation - MIT licence
              // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
              if (value == 0) {
                  return "0";
              }
              uint256 temp = value;
              uint256 digits;
              while (temp != 0) {
                  digits++;
                  temp /= 10;
              }
              bytes memory buffer = new bytes(digits);
              while (value != 0) {
                  digits -= 1;
                  buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
                  value /= 10;
              }
              return string(buffer);
          }
          /**
           * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
           */
          function toHexString(uint256 value) internal pure returns (string memory) {
              if (value == 0) {
                  return "0x00";
              }
              uint256 temp = value;
              uint256 length = 0;
              while (temp != 0) {
                  length++;
                  temp >>= 8;
              }
              return toHexString(value, length);
          }
          /**
           * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
           */
          function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
              bytes memory buffer = new bytes(2 * length + 2);
              buffer[0] = "0";
              buffer[1] = "x";
              for (uint256 i = 2 * length + 1; i > 1; --i) {
                  buffer[i] = _HEX_SYMBOLS[value & 0xf];
                  value >>= 4;
              }
              require(value == 0, "Strings: hex length insufficient");
              return string(buffer);
          }
          /**
           * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
           */
          function toHexString(address addr) internal pure returns (string memory) {
              return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev Interface of the ERC165 standard, as defined in the
       * https://eips.ethereum.org/EIPS/eip-165[EIP].
       *
       * Implementers can declare support of contract interfaces, which can then be
       * queried by others ({ERC165Checker}).
       *
       * For an implementation, see {ERC165}.
       */
      interface IERC165 {
          /**
           * @dev Returns true if this contract implements the interface defined by
           * `interfaceId`. See the corresponding
           * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
           * to learn more about how these ids are created.
           *
           * This function call must use less than 30 000 gas.
           */
          function supportsInterface(bytes4 interfaceId) external view returns (bool);
      }
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.0;
      import "@openzeppelin/contracts/access/Ownable.sol";
      import "../interfaces/ILayerZeroReceiver.sol";
      import "../interfaces/ILayerZeroUserApplicationConfig.sol";
      import "../interfaces/ILayerZeroEndpoint.sol";
      /*
       * a generic LzReceiver implementation
       */
      abstract contract LzApp is Ownable, ILayerZeroReceiver, ILayerZeroUserApplicationConfig {
          ILayerZeroEndpoint public immutable lzEndpoint;
          mapping(uint16 => bytes) public trustedRemoteLookup;
          event SetTrustedRemote(uint16 _srcChainId, bytes _srcAddress);
          constructor(address _endpoint) {
              lzEndpoint = ILayerZeroEndpoint(_endpoint);
          }
          function lzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) public virtual override {
              // lzReceive must be called by the endpoint for security
              require(_msgSender() == address(lzEndpoint), "LzReceiver: !endpoint");
              bytes memory trustedRemote = trustedRemoteLookup[_srcChainId];
              // if will still block the message pathway from (srcChainId, srcAddress). should not receive message from untrusted remote.
              require(_srcAddress.length == trustedRemote.length && keccak256(_srcAddress) == keccak256(trustedRemote), "LzReceiver: invalid source");
              _blockingLzReceive(_srcChainId, _srcAddress, _nonce, _payload);
          }
          // abstract function - the default behaviour of LayerZero is blocking. See: NonblockingLzApp if you dont need to enforce ordered messaging
          function _blockingLzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) internal virtual;
          function _lzSend(uint16 _dstChainId, bytes memory _payload, address payable _refundAddress, address _zroPaymentAddress, bytes memory _adapterParams) internal virtual {
              bytes memory trustedRemote = trustedRemoteLookup[_dstChainId];
              require(trustedRemote.length != 0, "LzSend: !trusted source.");
              lzEndpoint.send{value: msg.value}(_dstChainId, trustedRemote, _payload, _refundAddress, _zroPaymentAddress, _adapterParams);
          }
          //---------------------------UserApplication config----------------------------------------
          function getConfig(uint16 _version, uint16 _chainId, address, uint _configType) external view returns (bytes memory) {
              return lzEndpoint.getConfig(_version, _chainId, address(this), _configType);
          }
          // generic config for LayerZero user Application
          function setConfig(uint16 _version, uint16 _chainId, uint _configType, bytes calldata _config) external override onlyOwner {
              lzEndpoint.setConfig(_version, _chainId, _configType, _config);
          }
          function setSendVersion(uint16 _version) external override onlyOwner {
              lzEndpoint.setSendVersion(_version);
          }
          function setReceiveVersion(uint16 _version) external override onlyOwner {
              lzEndpoint.setReceiveVersion(_version);
          }
          function forceResumeReceive(uint16 _srcChainId, bytes calldata _srcAddress) external override onlyOwner {
              lzEndpoint.forceResumeReceive(_srcChainId, _srcAddress);
          }
          // allow owner to set it multiple times.
          function setTrustedRemote(uint16 _srcChainId, bytes calldata _srcAddress) external onlyOwner {
              trustedRemoteLookup[_srcChainId] = _srcAddress;
              emit SetTrustedRemote(_srcChainId, _srcAddress);
          }
          //--------------------------- VIEW FUNCTION ----------------------------------------
          function isTrustedRemote(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (bool) {
              bytes memory trustedSource = trustedRemoteLookup[_srcChainId];
              return keccak256(trustedSource) == keccak256(_srcAddress);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
      pragma solidity ^0.8.0;
      import "../utils/Context.sol";
      /**
       * @dev Contract module which provides a basic access control mechanism, where
       * there is an account (an owner) that can be granted exclusive access to
       * specific functions.
       *
       * By default, the owner account will be the one that deploys the contract. This
       * can later be changed with {transferOwnership}.
       *
       * This module is used through inheritance. It will make available the modifier
       * `onlyOwner`, which can be applied to your functions to restrict their use to
       * the owner.
       */
      abstract contract Ownable is Context {
          address private _owner;
          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
          /**
           * @dev Initializes the contract setting the deployer as the initial owner.
           */
          constructor() {
              _transferOwnership(_msgSender());
          }
          /**
           * @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 {
              require(owner() == _msgSender(), "Ownable: caller is not the owner");
          }
          /**
           * @dev Leaves the contract without owner. It will not be possible to call
           * `onlyOwner` functions anymore. Can only be called by the current owner.
           *
           * NOTE: Renouncing ownership will leave the contract without an owner,
           * thereby removing any functionality that is only available to the owner.
           */
          function renounceOwnership() public virtual onlyOwner {
              _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 {
              require(newOwner != address(0), "Ownable: new owner is the zero address");
              _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
      pragma solidity >=0.8.0;
      interface ILayerZeroReceiver {
          // @notice LayerZero endpoint will invoke this function to deliver the message on the destination
          // @param _srcChainId - the source endpoint identifier
          // @param _srcAddress - the source sending contract address from the source chain
          // @param _nonce - the ordered message nonce
          // @param _payload - the signed payload is the UA bytes has encoded to be sent
          function lzReceive(uint16 _srcChainId, bytes calldata _srcAddress, uint64 _nonce, bytes calldata _payload) external;
      }
      // SPDX-License-Identifier: MIT
      pragma solidity >=0.8.0;
      interface ILayerZeroUserApplicationConfig {
          // @notice set the configuration of the LayerZero messaging library of the specified version
          // @param _version - messaging library version
          // @param _chainId - the chainId for the pending config change
          // @param _configType - type of configuration. every messaging library has its own convention.
          // @param _config - configuration in the bytes. can encode arbitrary content.
          function setConfig(uint16 _version, uint16 _chainId, uint _configType, bytes calldata _config) external;
          // @notice set the send() LayerZero messaging library version to _version
          // @param _version - new messaging library version
          function setSendVersion(uint16 _version) external;
          // @notice set the lzReceive() LayerZero messaging library version to _version
          // @param _version - new messaging library version
          function setReceiveVersion(uint16 _version) external;
          // @notice Only when the UA needs to resume the message flow in blocking mode and clear the stored payload
          // @param _srcChainId - the chainId of the source chain
          // @param _srcAddress - the contract address of the source contract at the source chain
          function forceResumeReceive(uint16 _srcChainId, bytes calldata _srcAddress) external;
      }
      // SPDX-License-Identifier: MIT
      pragma solidity >=0.8.0;
      import "./ILayerZeroUserApplicationConfig.sol";
      interface ILayerZeroEndpoint is ILayerZeroUserApplicationConfig {
          // @notice send a LayerZero message to the specified address at a LayerZero endpoint.
          // @param _dstChainId - the destination chain identifier
          // @param _destination - the address on destination chain (in bytes). address length/format may vary by chains
          // @param _payload - a custom bytes payload to send to the destination contract
          // @param _refundAddress - if the source transaction is cheaper than the amount of value passed, refund the additional amount to this address
          // @param _zroPaymentAddress - the address of the ZRO token holder who would pay for the transaction
          // @param _adapterParams - parameters for custom functionality. e.g. receive airdropped native gas from the relayer on destination
          function send(uint16 _dstChainId, bytes calldata _destination, bytes calldata _payload, address payable _refundAddress, address _zroPaymentAddress, bytes calldata _adapterParams) external payable;
          // @notice used by the messaging library to publish verified payload
          // @param _srcChainId - the source chain identifier
          // @param _srcAddress - the source contract (as bytes) at the source chain
          // @param _dstAddress - the address on destination chain
          // @param _nonce - the unbound message ordering nonce
          // @param _gasLimit - the gas limit for external contract execution
          // @param _payload - verified payload to send to the destination contract
          function receivePayload(uint16 _srcChainId, bytes calldata _srcAddress, address _dstAddress, uint64 _nonce, uint _gasLimit, bytes calldata _payload) external;
          // @notice get the inboundNonce of a lzApp from a source chain which could be EVM or non-EVM chain
          // @param _srcChainId - the source chain identifier
          // @param _srcAddress - the source chain contract address
          function getInboundNonce(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (uint64);
          // @notice get the outboundNonce from this source chain which, consequently, is always an EVM
          // @param _srcAddress - the source chain contract address
          function getOutboundNonce(uint16 _dstChainId, address _srcAddress) external view returns (uint64);
          // @notice gets a quote in source native gas, for the amount that send() requires to pay for message delivery
          // @param _dstChainId - the destination chain identifier
          // @param _userApplication - the user app address on this EVM chain
          // @param _payload - the custom message to send over LayerZero
          // @param _payInZRO - if false, user app pays the protocol fee in native token
          // @param _adapterParam - parameters for the adapter service, e.g. send some dust native token to dstChain
          function estimateFees(uint16 _dstChainId, address _userApplication, bytes calldata _payload, bool _payInZRO, bytes calldata _adapterParam) external view returns (uint nativeFee, uint zroFee);
          // @notice get this Endpoint's immutable source identifier
          function getChainId() external view returns (uint16);
          // @notice the interface to retry failed message on this Endpoint destination
          // @param _srcChainId - the source chain identifier
          // @param _srcAddress - the source chain contract address
          // @param _payload - the payload to be retried
          function retryPayload(uint16 _srcChainId, bytes calldata _srcAddress, bytes calldata _payload) external;
          // @notice query if any STORED payload (message blocking) at the endpoint.
          // @param _srcChainId - the source chain identifier
          // @param _srcAddress - the source chain contract address
          function hasStoredPayload(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (bool);
          // @notice query if the _libraryAddress is valid for sending msgs.
          // @param _userApplication - the user app address on this EVM chain
          function getSendLibraryAddress(address _userApplication) external view returns (address);
          // @notice query if the _libraryAddress is valid for receiving msgs.
          // @param _userApplication - the user app address on this EVM chain
          function getReceiveLibraryAddress(address _userApplication) external view returns (address);
          // @notice query if the non-reentrancy guard for send() is on
          // @return true if the guard is on. false otherwise
          function isSendingPayload() external view returns (bool);
          // @notice query if the non-reentrancy guard for receive() is on
          // @return true if the guard is on. false otherwise
          function isReceivingPayload() external view returns (bool);
          // @notice get the configuration of the LayerZero messaging library of the specified version
          // @param _version - messaging library version
          // @param _chainId - the chainId for the pending config change
          // @param _userApplication - the contract address of the user application
          // @param _configType - type of configuration. every messaging library has its own convention.
          function getConfig(uint16 _version, uint16 _chainId, address _userApplication, uint _configType) external view returns (bytes memory);
          // @notice get the send() LayerZero messaging library version
          // @param _userApplication - the contract address of the user application
          function getSendVersion(address _userApplication) external view returns (uint16);
          // @notice get the lzReceive() LayerZero messaging library version
          // @param _userApplication - the contract address of the user application
          function getReceiveVersion(address _userApplication) external view returns (uint16);
      }